JP2008010027A - Light source unit for heat assisted magnetic recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means in a thin film magnetic head having a structure where the mounting surface and the ABS are orthogonal, that can prevent the oscillation property of the light source from degrading by the reflected return light by installing the light source apart from the ABS and also prevent the production yield of the whole head from falling by the defect rate of the light source and the installation position errors. <P>SOLUTION: This light source unit has a unit substrate having an adhering surface on the slider at the side opposite to the ABS, a propagation layer provided on the element forming surface orthogonal to the adhering surface of the unit substrate, a dugout formed on the surface opposite to the adhering surface of the unit substrate, a light source provided in this dugout, a lens, and a light path changer. The light source is set inclined so that the light emitted from it proceeds in a direction tilted from the direction perpendicular to the element forming surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a light source unit including a light source such as a laser diode, a thin film magnetic head including the light source unit, and a thin film magnetic head, which are constituent elements of a thin film magnetic head that writes signals by a thermally assisted magnetic recording method. The present invention relates to a head gimbal assembly (HGA) provided and a magnetic disk device provided with the HGA.

  As the recording density of magnetic disk devices increases, further improvements in performance of thin film magnetic heads are required. As a thin film magnetic head, a composite thin film magnetic head having a structure in which a magnetoresistive (MR) effect element for reading and an electromagnetic coil element for writing are stacked is widely used. Data signals are read from and written to a magnetic disk.

  Generally, a magnetic recording medium is a discontinuous body in which magnetic fine particles are aggregated, and each magnetic fine particle has a single magnetic domain structure. Here, one recording bit is composed of a plurality of magnetic fine particles. Therefore, in order to increase the recording density, the magnetic fine particles must be made smaller to reduce the irregularities at the boundaries of the recording bits. However, if the magnetic fine particles are made smaller, a decrease in the thermal stability of magnetization accompanying volume reduction becomes a problem.

A measure of the thermal stability of magnetization is given by K _U V / k _B T. Here, K _U is the magnetic anisotropy energy, V the magnetic microparticle volume of one magnetic particle, k _B the Boltzmann constant, T is the absolute temperature. Making the magnetic fine particles smaller means exactly reducing V, and if it is left as it is, K _U V / k _B T becomes smaller and thermal stability is impaired. As a countermeasure to this problem, it is conceivable to increase the K _U simultaneously, increase in K _U results in an increase in the coercive force of the recording medium. On the other hand, the write magnetic field strength by the magnetic head is almost determined by the saturation magnetic flux density of the soft magnetic material constituting the magnetic pole in the head. Therefore, if the coercive force exceeds an allowable value determined from the limit of the write magnetic field strength, writing becomes impossible.

As a first method for solving the problem of the thermal stability of magnetization, a transition from the in-plane magnetic recording method to the perpendicular magnetic recording method can be considered. In the perpendicular magnetic recording medium, the recording layer thickness can be increased, and as a result, V can be increased to improve the thermal stability. As a second method, use of patterned media can be considered. In normal magnetic recording, as described above, one recording bit is composed of N magnetic fine particles and recorded, but using a patterned medium, one recording bit is set as one area of volume NV. As a result, the thermal stability index becomes K _U NV / k _B T, and the thermal stability is dramatically improved.

Further, as a third method for solving the thermal stability problem, while using a large magnetic material K _U, by applying heat to the recording medium immediately before the write magnetic field is applied, the write to reduce the coercive force A so-called heat-assisted magnetic recording system has been proposed. This method is roughly classified into a magnetic dominant recording method and an optical dominant recording method. In the magnetic dominant recording method, the main subject of writing is an electromagnetic coil element, and the radiation diameter of light is larger than the track width (recording width). On the other hand, in the optical dominant recording method, the main subject of writing is the light emitting portion, and the light emission diameter is substantially the same as the track width (recording width). That is, the magnetic dominant recording method gives the spatial resolution to the magnetic field, whereas the optical dominant recording method gives the spatial resolution to the light.

  In this thermally assisted magnetic recording system, as a light emitting part for irradiating a recording medium with light, in Patent Document 1, a metal scatterer having a shape such as a cone formed on a substrate, and the scatterer A near-field optical probe including a film made of a dielectric or the like formed around the periphery of the substrate is disclosed. In Patent Document 2, a head using a solid immersion lens in a recording / reproducing apparatus is disclosed. Further, in Patent Document 3, a scatterer constituting a near-field optical probe is formed in contact with the main magnetic pole of a single magnetic pole write head for perpendicular magnetic recording so that the irradiated surface is perpendicular to the recording medium. The configuration is disclosed. Further, Non-Patent Document 1 discloses a U-shaped near-field optical probe formed on a quartz slider. Furthermore, Non-Patent Document 2 discloses a grating in which a diffraction grating that transmits light well is abutted against a diffraction grating that transmits little light.

  As described above, various light emitting portions have been proposed in practice, but what is very important in realizing heat-assisted magnetic recording is that this is provided near the air bearing surface (ABS) of the head. This is means for supplying laser light to the light emitting section.

  For example, the techniques disclosed in Patent Documents 4 and 5 use an optical fiber for supplying laser light. Here, Patent Document 4 discloses a configuration in which a metal film having pinholes is provided on an end face of an optical fiber or the like cut obliquely. Patent Document 5 discloses an optical flying head provided with a movable mirror for appropriately directing laser light emitted from an optical fiber to a lens optical system.

  On the other hand, the techniques disclosed in Patent Document 6 and Patent Document 3 use a semiconductor laser element provided in the head for supplying laser light. Here, Patent Document 6 discloses a configuration in which heat assist is performed by irradiating light from a built-in laser element portion to a minute optical aperture facing a medium. Patent Document 3 discloses a configuration in which a laser element is provided near the ABS or above a head element, and the laser beam is irradiated to a scatterer constituting the above-mentioned near-field light probe.

  Here, an optical fiber as a laser beam supply means is compared with a semiconductor laser element provided in the head. When an optical fiber is used, it is not necessary to form a complicated structure like a semiconductor laser inside the head, and fine near-field light having a desired intensity can be obtained relatively easily. However, when the optical fiber is fixed to the head, it is necessary to bend the optical fiber considerably. In particular, the allowable bending radius is large in a glass fiber, and bending is difficult. In the case of a plastic fiber, the allowable bending radius is reduced to some extent, but the loss is high and the propagation efficiency is lowered.

  In addition, when using an optical fiber, the optical fiber that jumps out of the head may be shaken, adversely affecting the flying characteristics of the slider, or if the head is placed between magnetic disks, there is a risk of contact. There is. In addition, a very large loss occurs at the joint between the optical fiber end and the light source, waveguide layer, or the like. On the other hand, when the semiconductor laser is provided in the head, such a problem does not occur, and the laser beam can be supplied with a relatively low loss without greatly affecting the flying characteristics.

JP 2001-255254 A JP-A-10-162444 JP 2004-158067 A JP 2000-173093 A Japanese translation of PCT publication No. 2002-511176 JP 2001-283404 A ShintaroMiyanishi et al. “Near-field Assisted Magnetic Recording” IEEE TRANSACTIONS ONMAGNETICS, 2005, Vol. 41, No. 10, p. 2817-2821 Koji Shono and Mitsuga Oshiki “Current Status and Issues of Thermally Assisted Magnetic Recording” Journal of Japan Society of Applied Magnetics, 2005, Vol. 29, No. 1, p. 5-13

  However, even when a light source such as a semiconductor laser is used to introduce light, the production rate of the head is reduced due to the defect rate of the light source and the installation position error, and the laser oscillation operation is unstable due to reflected return light, etc. Was a problem.

  In general, in a diode chip of a semiconductor laser, it is very difficult to perform nondestructive evaluation of characteristics such as output, laser beam divergence angle, and lifetime. Therefore, when the semiconductor laser is provided in the head, the characteristics are evaluated after the semiconductor laser is installed on the slider or the like, and the quality is determined. Furthermore, despite the fact that it is quite difficult to properly adjust the delicate positional relationship between the semiconductor laser and other optical elements, particularly where near-field light is generated, the position of the semiconductor laser once installed is Change is almost impossible. Therefore, in practice, it is very difficult to eliminate or reduce an error in the installation position of the semiconductor laser, particularly a manufacturing error related to the positional relationship with other optical elements.

  As a result, the yield of the magnetic head, the yield of the semiconductor laser itself, and the yield related to the installation position of the semiconductor laser all affect the manufacturing yield of the entire head, and the yield of the entire head is significantly reduced. End up.

  Considering the problem of installation of the light source on the slider, for example, as disclosed in Patent Document 3, in order to appropriately irradiate light to the scatterer, the light source is extremely applied to the recording medium near the head end surface. When it is installed at a close position, there is a possibility that the light source position is in contact with the recording medium, which is very undesirable from the viewpoint of the reliability of the apparatus.

  On the other hand, for example, according to the technique described in Non-Patent Document 1, light can be incident in a state where a light source such as a semiconductor laser is away from the medium surface. In this case, the light converged from the optical pickup head is directly incident on the near-field optical probe. However, this technique is based on the premise that the integrated surface of the near-field optical probe and the medium facing surface coincide with each other, and the general thin film magnetic field in which the integrated surface and the medium facing surface (ABS) are perpendicular to each other. Unlike the configuration of the head, the affinity is not good. That is, for example, it is very difficult to apply to a thin film magnetic head provided with a vertical conduction type giant magnetoresistive (CPP (Current Perpendicular to Plain) -GMR) effect element or an electromagnetic coil element for perpendicular magnetic recording.

  In addition, when the semiconductor laser is mounted on the head in a state of being away from the medium surface, there are usually many interfaces with different refractive indexes on the optical path, and a part of the laser beam is reflected at this interface. Then, it returns to the semiconductor laser as reflected return light. In particular, the light emitted from the light emitting end of the semiconductor laser is reflected at a considerable rate on the incident surface when entering the head, and can be a large reflected return light. As a result, the oscillation operation of the semiconductor laser becomes unstable and the oscillation characteristics deteriorate.

  Accordingly, an object of the present invention is to prevent a decrease in oscillation characteristics of a light source due to reflected return light in a thin film magnetic head having a structure in which an integration surface and ABS are perpendicular to each other, after the light source is installed at a position away from the ABS. Further, it is an object to provide a means capable of avoiding a decrease in the manufacturing yield of the entire head due to an error of a defective light source and an installation position.

  Another object of the present invention is to provide a thin film magnetic head using such means, an HGA equipped with the thin film magnetic head, and a magnetic disk drive equipped with the HGA.

  Before describing the present invention, the terms used in the specification are defined. In the laminated structure of the magnetic head elements formed on the integration surface of the substrate, the component on the substrate side of the reference layer is assumed to be “below” or “below” the reference layer, and the reference layer It is assumed that the component on the side in which the layers are stacked is “above” or “above” the reference layer.

  According to the present invention, the unit substrate having an adhesive surface bonded to the surface of the slider opposite to the ABS, and the adhesive surface of the unit substrate are provided on the element forming surface perpendicular to each other. The propagation layer including the optical path of the recording light, the pit formed on the surface opposite to the bonding surface of the unit substrate, and the radiated light for heat-assisted magnetic recording provided in the digging A light source, a lens unit provided in the propagation layer for adjusting the propagation of light, and an optical path changing unit provided in the propagation layer for directing the light toward the end surface of the propagation layer on the bonding surface side Thus, a light source unit for thermally assisted magnetic recording is provided in which the light source is tilted so that light emitted from the light source proceeds in a direction inclined from a direction perpendicular to the element formation surface.

  The laser light emitted from the light source installed in such a manner proceeds in a direction inclined from a direction perpendicular to the element formation surface, and obliquely (with an incident angle greater than zero) on the side surface (incident side surface) of the digging ) Incident. Therefore, the reflected part of the laser light incident on the incident side surface proceeds with a reflection angle that is the same as the incident angle described above, and therefore does not return to the light source and does not become so-called reflected return light. As a result, instability of the oscillation operation of the light source is avoided, and the oscillation characteristics are maintained well.

  Further, when a thin film magnetic head is manufactured by combining the light source unit according to the present invention and a slider, for example, if the characteristics of the light source unit are evaluated in advance and only non-defective products are used for manufacturing the thin film magnetic head, the head manufacturing is performed. The yield of the entire head at that time is almost the manufacturing yield of the slider, and a reduction in the manufacturing yield of the entire head due to the defective product rate of the light source unit can be avoided.

  Furthermore, since the light source unit according to the present invention is adhered to the surface of the slider opposite to the ABS, the light source can always be installed at a position away from the ABS. Furthermore, by using such a light source unit, it is possible to make the slider have light having an appropriate traveling direction and adjusted propagation. That is, in a thin film magnetic head having a structure in which the integration surface and the ABS are perpendicular, light having an appropriate size and direction can be reliably supplied. As a result, heat-assisted magnetic recording with high heating efficiency of the magnetic recording medium can be realized.

  Also, in the light source unit according to the present invention, the light source is inclined and installed such that the bottom surface portion on the light exit end side of the light source is separated from the bottom surface of the dugout than the bottom surface portion on the side opposite to the light output end of the light source. It is preferable that In this case, the digging is formed on the surface opposite to the bonding surface of the unit substrate and the propagation layer, extends to both the unit substrate and the propagation layer, and further, at the bottom of the portion extending to the propagation layer. A pedestal is provided, and it is preferable that the light source is installed in an inclined manner so that the bottom surface portion on the light output end side is placed on the pedestal. Here, it is preferable that the light source is installed with the bottom side opposite to the light exit end of the light source being in contact with the bottom surface of the dug. Furthermore, it is preferable that the light source is installed with the upper side opposite to the light exit end of the light source being in contact with the side surface of the digging.

  When a light source is mounted on a digging with such a pedestal, the installation position and inclination of the light source are determined by the position of the pedestal and the height of the top surface, the position of the bottom that is in contact with the bottom of the digging, and the side of the digging. It is determined by the position of the upper side. Here, since the dimensions of the excavation including the pedestal can be controlled with a predetermined accuracy by using a fine processing technique, the light source can be installed with a predetermined accuracy with respect to the position and the inclination. As a result, it is possible to prevent a decrease in the manufacturing yield of the entire head due to an error in the installation position of the light source while preventing a decrease in the oscillation characteristics of the light source due to the reflected return light.

  In the light source unit according to the present invention, it is preferable that the light source is a laser diode having a light emitting end directed to the propagation layer. In this case, it is preferable that the unit substrate has conductivity and the electrode forming the bottom surface of the laser diode is electrically connected to the unit substrate. Furthermore, it is preferable that at least one drive terminal electrode for a laser diode is provided on a surface opposite to the bonding surface of the unit substrate.

  Furthermore, in the light source unit according to the present invention, it is preferable that the optical path changing portion is a prism portion formed obliquely with respect to the element formation surface of the unit substrate and having the propagation layer as a reflection surface. Moreover, it is preferable that the lens unit is provided at a position on the optical path before the light reaches the optical path changing unit. Further, it is preferable that the lens unit is a diffractive optical element unit.

  Further, in the light source unit according to the present invention, the light emitted from the end surface on the adhesion surface side of the propagation layer has a direction perpendicular to the adhesion surface, and further the light whose propagation is adjusted, for example, aligned in parallel. Preferably, the light is focused or focused.

  According to the present invention, there is further provided a unit processing bar in which individual chips after separation become the light source unit described above by being cut and separated.

According to the present invention, furthermore, the slider substrate having the ABS and the integrated surface perpendicular to the ABS, the magnetic head element formed on the integrated surface, and the light received from the end surface on the opposite side of the ABS to the ABS. A slider having a waveguide layer for propagating toward the slider end surface on the side, and a covering layer formed on the integrated surface so as to cover the magnetic head element and the waveguide layer;
The adhesive surface is in contact with the surface of the slider opposite to the ABS, so that light emitted from the end surface of the propagation layer on the adhesive surface side propagates through the waveguide layer and reaches the slider end surface on the ABS side. There is provided a thin film magnetic head comprising the light source unit described above fixed in position.

  In the thin film magnetic head according to the present invention, the slider is provided at a position in contact with the ABS end face of the waveguide layer or at a position close to the end face. When the data signal is written by generating near-field light. It is preferable to further include a near-field light generator having an end reaching the slider end surface on the ABS side for heating the magnetic recording medium.

  Further, according to the present invention, the thin film magnetic head described above, a support mechanism for supporting the thin film magnetic head, a signal line for the magnetic head element, and a power supply line for the light source are provided. An HGA is provided.

  Further, according to the present invention, at least one such HGA is provided, and at least one magnetic recording medium, and writing and reading operations performed by the thin film magnetic head on the at least one magnetic recording medium are controlled. In addition, a magnetic disk device further provided with a recording / reproducing and light emission control circuit for controlling the light emission operation of the light source is provided.

  According to the light source unit for thermally assisted magnetic recording according to the present invention, the thin film magnetic head including the light source unit, the HGA including the thin film magnetic head, and the magnetic disk device including the HGA, the integration surface and the ABS are perpendicular to each other. In the head configuration, the light source can be installed at a position away from the ABS, and the deterioration of the oscillation characteristics of the light source due to the reflected return light can be prevented. Further, the entire head due to the defective product rate of the light source and the installation position error can be prevented. A decrease in manufacturing yield can be avoided.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail, referring an accompanying drawing. In the drawings, the same elements are denoted by the same reference numerals. In addition, the dimensional ratios in the components in the drawings and between the components are arbitrary for easy viewing of the drawings.

  FIG. 1 is a perspective view schematically showing a configuration of a main part in an embodiment of a magnetic disk device and an HGA according to the present invention. Here, in the perspective view of the HGA, the side facing the surface of the magnetic disk of the HGA is displayed facing up.

  In the figure, 10 is a magnetic disk which is a plurality of magnetic recording media rotating around the rotation axis of the spindle motor 11, 12 is an assembly carriage device for positioning the thin film magnetic head 21 on the track, and 13 is A recording / reproducing and light emission control circuit for controlling writing and reading operations of the thin-film magnetic head 21 and for controlling a laser diode as a light source for generating laser light for heat-assisted magnetic recording, which will be described in detail later, are shown. Yes.

  The assembly carriage device 12 is provided with a plurality of drive arms 14. These drive arms 14 can be angularly swung about a pivot bearing shaft 16 by a voice coil motor (VCM) 15 and are stacked in a direction along the shaft 16. An HGA 17 is attached to the tip of each drive arm 14. Each HGA 17 is provided with a thin film magnetic head 21 so as to face the surface of each magnetic disk 10. The magnetic disk 10, the drive arm 14, the HGA 17, and the thin film magnetic head 21 may be singular.

  The HGA 17 is configured by fixing a thin film magnetic head 21 to the tip of the suspension 20 and further electrically connecting one end of a wiring member 203 to a terminal electrode of the thin film magnetic head 21. The suspension 20 includes a load beam 200, an elastic flexure 201 fixed and supported on the load beam 200, a base plate 202 provided at the base of the load beam 200, and a lead conductor provided on the flexure 201. And a wiring member 203 composed of connection pads electrically connected to both ends thereof.

  It is obvious that the suspension structure in the HGA 17 of the present invention is not limited to the structure described above. Although not shown, a head driving IC chip may be mounted in the middle of the suspension 20.

  FIG. 2 is a perspective view showing an embodiment of the thin film magnetic head 21 according to the present invention.

  According to FIG. 2, the thin film magnetic head 21 includes a slider 22 having a magnetic head element 32 for writing and reading data signals, and a light source unit 23 having a laser diode 40 serving as a light source for thermally assisted magnetic recording. However, it has a configuration in which the respective back surface 2201 and the bonding surface 2300 are brought into contact with each other and bonded and fixed. Here, the back surface 2201 of the slider 22 is the surface of the slider 22 opposite to the ABS 2200.

  The slider 22 reads a data signal formed on a slider substrate 220 having an ABS 2200 which is a medium facing surface processed so as to obtain an appropriate flying height, and an integrated surface 2202 perpendicular to the ABS 2200 of the slider substrate 220. A magnetic head element 32 composed of an MR effect element 33 and an electromagnetic coil element 34 for writing a data signal, a waveguide layer 35 provided between the MR effect element 33 and the electromagnetic coil element 34, and a magnetic disk An integrated surface 2202 so as to cover the near-field light generator 36 for generating near-field light for heating the recording layer portion, and the MR effect element 33, the electromagnetic coil element 34, the waveguide layer 35, and the near-field light generator 36. The MR effect element 33 and the electromagnetic coil element 34 that are exposed from the layer surface of the cover layer 38 formed on the cover layer 38 are exposed to 2 Each and a total of four signal electrodes 37 are connected.

  One end of the MR effect element 33, the electromagnetic coil element 34, and the near-field light generating unit 36 reaches the slider end surface 221 on the ABS 2200 side. Here, the slider end surface 221 is a surface of the slider 22 on the ABS 2200 side and a portion other than the ABS 2200. During the actual writing or reading operation, the thin film magnetic head 21 floats hydrodynamically on the surface of the rotating magnetic disk with a predetermined flying height. At this time, the MR effect element 33 and the end of the electromagnetic coil element 34 are opposed to the magnetic disk through a minute spacing, whereby reading by sensing the data signal magnetic field and writing by applying the data signal magnetic field are performed.

  Here, when the data signal is written, the laser light propagating from the light source unit 23 through the waveguide layer 35 irradiates the near-field light generating unit 36, and by this irradiation, the slider end surface of the near-field light generating unit 36. Near-field light is generated from the end reaching 221. With this near-field light, heat-assisted magnetic recording can be performed as described later.

  The waveguide layer 35 has two side surfaces 351 that are curved along a parabola and that are opposite to each other in the track width direction, and are aligned in parallel to the incident surface 352 that reaches the slider end surface 222 opposite to the ABS 2200. The reflected laser light 39 can be condensed on the condensing surface 350 which is the end surface on the slider end surface 221 side by reflection on the both side surfaces 351. The slider end surface 222 is a surface on the side opposite to the ABS 2200 of the slider 22 and is a surface other than the back surface 2201. Further, the near-field light generating part 36 is in contact with a fine near-field light gap part 361 whose one end is in contact with the condensing surface 350 of the waveguide layer 35 and whose other end reaches the slider end face 221. Are provided with two opposing metal layers 360 that face each other through the near-field light gap portion 361. In the near-field light generating part 36, the near-field light gap part 361 and the opposing metal layer 360 sandwiching the fine near-field light gap part 361 realize a so-called “bow tie type” structure. In this “bow tie type” structure, a very strong electric field concentration occurs at the center.

  The electric field strength of this near-field light is orders of magnitude stronger than that of incident light, and this very strong near-field light rapidly heats the opposing local portion of the magnetic disk surface. As a result, the coercive force of this local portion is reduced to a size that allows writing by a write magnetic field, so that even if a high coercivity magnetic disk for high-density recording is used, writing by the electromagnetic coil element 34 is possible. Become. The near-field light is present in a region from the slider end surface 221 toward the surface of the magnetic disk up to the width or the layer thickness of the near-field light gap portion 361 described above in the track width direction. Accordingly, in the present situation where the flying height is 10 nm or less, the near-field light can sufficiently reach the recording layer portion. Further, the width of the near-field light generated in this way is approximately the same as the above-described width or layer thickness, and the electric field intensity of the near-field light is exponentially in a region greater than this width or layer thickness. Since it attenuates, the recording layer portion of the magnetic disk can be heated very locally.

  Similarly, according to FIG. 2, the light source unit 23 is provided on a unit substrate 230 having an adhesive surface 2300 bonded to the back surface 2201 of the slider 22 and an element forming surface 2302, and is emitted from a laser diode 40 described later. The propagation layer 41 for propagating the laser light to the end surface 410 on its own adhesion surface side and the unit upper surface 2301 opposite to the unit substrate adhesion surface 2300 and the propagation layer 41 adhesion Formed on the end surface 411 opposite to the surface 2300, extending to both the unit substrate 230 and the propagation layer 41, and disposed in the recess 45, and laser light for heat-assisted magnetic recording Of the laser light emitted from the laser diode 40, which is provided in the propagation layer 41. A diffractive optical element part 42 as a lens part for adjustment and a propagation layer 41 are provided on the propagation layer 41 and formed obliquely with respect to the element formation surface 2302. Are provided with a prism portion 43 as an optical path changing portion for directing the laser beam toward the end face 410, and drive terminal electrodes 440 and 441 for the laser diode 40.

  Here, the excavation 45 includes a pedestal 453 at the bottom of the portion extending to the propagation layer 41. The pedestal 453 is provided with the incident side surface 451 on which the laser beam emitted from the laser diode 40 is incident in the trench 45, and has a stepped shape. The laser diode 40 is inclined and installed such that the bottom surface portion on the light output end 400 side of the laser diode 40 is placed on the base 453. In addition, the laser diode 40 is installed such that an end of the bottom surface 401 opposite to the light output end 400, that is, a bottom side 4010 opposite to the light output end 400, contacts the bottom surface 450 of the digging 45. In other words, the laser diode 40 is inclined and installed such that the bottom surface portion on the light exit end 400 side of the laser diode 40 is farther from the bottom surface 450 of the digging 45 than the bottom surface portion opposite to the light exit end 400. ing.

  As a result, the laser light emitted from the light emitting end 400 of the laser diode 40 travels in a direction inclined from a direction perpendicular to the element formation surface 2302 and enters the incident side surface 451 obliquely (with an incident angle greater than zero). And propagates in the propagation layer 41. At this time, since the propagation layer 41 has a larger refractive index than the atmosphere in the magnetic disk device (refractive index n is about 1), the laser light is refracted at the incident side surface 451 at a refractive angle larger than the incident angle. The refraction proceeds in a direction away from the end surface 410 of the propagation layer 41 on the adhesion surface 2300 side at a larger angle.

  In addition, the portion of the laser light incident on the incident side surface 451 is reflected and travels at a reflection angle that is the same as the incident angle described above, and therefore does not return to the light exit end 400 and does not become reflected return light. As a result, instability of the oscillation operation of the laser diode 40 is avoided, and the oscillation characteristics are maintained well.

  Further, the laser light spreads centering on the traveling direction as it propagates through the propagation layer 41, but it passes through the diffractive optical element part 42 provided in the propagation layer 41, and is collimated or focused. Converted to light. The laser light whose propagation is adjusted in this way reaches the reflection surface 430 of the prism portion 43 and is totally reflected on the same surface, whereby the traveling direction thereof is changed. Thereafter, the laser light propagates to the end surface 410 on the adhesion surface 2300 side of the propagation layer 41, is emitted from the end surface 410, and propagates to the end surface 352 of the waveguide layer 35 in a direction parallel to the layer surface of the same layer. Incident as light.

  Although the configuration of the slider 22 and the light source unit 23 has been described above, the thin film magnetic head 21 has a configuration in which the slider 22 and the light source unit 23 are combined, and is manufactured by combining them after forming each. be able to. Therefore, for example, if the characteristics of the light source unit are evaluated in advance and only non-defective products are used for the production of thin film magnetic heads, the production yield of the entire head at the time of head production will be substantially the production yield of the slider, resulting in a defective product of the light source unit. It is possible to avoid a decrease in the manufacturing yield of the entire head due to the rate.

  Further, since the light source unit 23 is adhered to the back surface 2201 of the slider 22 opposite to the ABS 2200, the laser diode 40 can always be installed at a position away from the ABS 2200.

  Further, by using such a light source unit 23, as described above, the laser beam propagating in the direction parallel to the layer surface of the same layer can be made incident on the end surface 352 of the waveguide layer 35 of the slider 22. That is, in the thin film magnetic head 21 having a configuration in which the integration surface 2202 and the ABS 2200 are perpendicular, laser light having an appropriate size and direction can be reliably supplied. As a result, heat-assisted magnetic recording with high heating efficiency of the recording layer of the magnetic disk can be realized.

  The sizes of the slider 22 and the light source unit 23 are arbitrary. For example, the slider 22 may be a so-called femto slider having a width in the track width direction of 700 μm × length (depth) 850 μm × thickness 230 μm. In this case, the light source unit 23 may be one size smaller than this, for example, a width of 650 μm in the track width direction × a length (depth) of 700 μm × a thickness of 180 μm. Actually, for example, a typical size of a laser diode that is usually used is about 250 μm wide × 250 μm long (depth) × 65 μm thick. For example, the unit upper surface 2301 (and the propagation layer) of the light source unit 23 of this size. It is sufficiently possible to form a recess 45 having a base 453 on which the laser diode 40 of this size can be inclined and installed on the end face 411) of 41.

  At this time, if the depth of the upper surface of the pedestal 453 from the unit upper surface 2301 is made deeper by several μm than 65 μm, the upper surface of the laser diode 40 can be made equal to or lower than the unit upper surface 2301. However, the depth of the dig 45 may be about 30 μm, for example, and the upper surface portion of the laser diode 40 on the light output end 400 side may be slightly protruded. Further, by reducing the size of the light source unit 23 within a range in which the laser diode 40 can be installed, a larger number of light source units 23 can be obtained from one substrate wafer.

  Further, in the spot of the laser beam reaching the end surface 410 of the propagation layer 41, the diameter in the track width direction can be set to about 5 to 40 μm, for example, and the diameter orthogonal to the diameter can be set to about 1 to 6 μm, for example. On the other hand, the thickness of the waveguide layer 35 that receives this laser light can be set to about 1 to 6 μm, for example, and the width in the track width direction at the end face 352 of the waveguide layer 35 can be set to about 50 to 500 μm, for example. When the size is set as described above, the light emitted from the end surface 410 of the propagation layer 41 propagates through the waveguide layer 35 and reaches the slider end surface 221 (near-field light generating unit 36) on the ABS 2200 side. When aligning the positions of the slider 22 and the light source unit 23, the alignment in the track width direction can be performed relatively easily as compared with the alignment in the direction perpendicular to the track width direction.

  Further, in the optical adjustment of the entire thin film magnetic head 21, before the alignment of the slider 22 and the light source unit 23 described above, the installation position and inclination of the laser diode 40 in the digging 45 in the light source unit 23. Need to be adjusted. Actually, the diffractive optical element part 42, the prism part 43, etc. are formed with a predetermined accuracy using a thin film micromachining technique or a precision machining technique, so that the installation position and inclination of the laser diode 40 with respect to these optical systems can be determined. Accuracy is very important. Here, the excavation 45 has a structure that improves the accuracy of the installation position by providing the pedestal 453, and details will be described later with reference to another drawing.

  In this embodiment, the pedestal 453 is used to install the laser diode 40 as a light source at an angle, but the laser light emitted from the laser diode 40 is viewed from a direction perpendicular to the element formation surface 2302. Other installation means may be used as long as it can be installed so as to proceed in an inclined direction. For example, a stand for installation that is independent from the propagation layer 41 may be provided on the bottom surface 450 of the trench 45.

As another embodiment regarding the slider 22, the condensing surface 350 of the waveguide layer 35 is exposed from the slider end surface 221 without providing the near-field light generating portion 36 in the slider 22, and collected on the magnetic disk. The magnetic disk may be heated by irradiating the irradiated laser beam. In this case, for example, by heating the magnetic disk only when the use environment of the magnetic disk device is low, to it is also preferable to keep the coercive force H _C of at least room temperature, then irradiated continuously with the laser beam on the magnetic disk It is also preferable to maintain the magnetic disk at a high temperature of, for example, 100 ° C. or higher.

  3A is a cross-sectional view taken along the line AA of FIG. 2, schematically showing the configuration of the main part of the thin-film magnetic head 21 shown in FIG. 2, and FIG. 4 is a plan view showing the shape of the end of the slider end surface 221 of the near-field light generating unit 36. FIG.

  First, components of the slider 22 of the thin film magnetic head 21 will be described.

In the slider 22 of FIG. 3A, reference numeral 220 denotes a slider substrate made of AlTiC (Al ₂ O ₃ —TiC) or the like, and has an ABS 2200 facing the surface of the magnetic disk. An MR effect element 33 for reading, an electromagnetic coil element 34 for writing, and a coating layer 38 for protecting these elements are formed on the integrated surface 2202 which is one side surface of the slider substrate 220 with the ABS 2200 as the bottom surface. Is mainly formed.

  The MR effect element 33 includes an MR multilayer 332, and a lower shield layer 330 and an upper shield layer 334 disposed at positions sandwiching the multilayer. The lower shield layer 330 and the upper shield layer 334 may be made of, for example, NiFe, CoFeNi, CoFe, FeN, or FeZrN having a thickness of about 0.5 to 3 μm formed by a pattern plating method including a frame plating method. it can.

  The MR multilayer 332 is composed of a current in plain (CIP) giant magnetoresistive (GMR) multilayer film, a vertical current type (CPP (Current Perpendicular to Plain)) GMR multilayer film, or a tunnel. It includes a magnetoresistive (TMR (Tunnel Magneto Resistive)) multilayer film and senses a signal magnetic field from a magnetic disk with very high sensitivity. The upper and lower shield layers 334 and 330 prevent the MR multilayer 332 from being affected by an external magnetic field that causes noise.

  When the MR multilayer 332 includes a CIP-GMR multilayer film, insulating upper and lower shield gap layers are provided between the upper and lower shield layers 334 and 330 and the MR multilayer 332, respectively. Further, an MR lead conductor layer for supplying a sense current to the MR multilayer 332 and taking out a reproduction output is formed. On the other hand, when the MR multilayer 332 includes a CPP-GMR multilayer film or a TMR multilayer film, the upper and lower shield layers 334 and 330 also function as upper and lower electrode layers, respectively. In this case, the upper and lower shield gap layers and the MR lead conductor layer are unnecessary and are omitted. Although not shown, an insulating layer is formed between the shield layers on the opposite side of the slider end surface 221 of the MR multilayer 332, and an insulating layer is formed on both sides of the MR multilayer 332 in the track width direction. Alternatively, a bias insulating layer and a hard bias layer made of a ferromagnetic material for applying a longitudinal bias magnetic field for stabilizing the magnetic domain are formed.

  When the MR multilayer 332 includes, for example, a TMR effect multilayer film, the antiferromagnetic layer having a thickness of about 5 to 15 nm made of IrMn, PtMn, NiMn, RuRhMn, and the like, and CoFe that is a ferromagnetic material, for example, or Ru A magnetization pinned layer composed of two layers of CoFe or the like with a nonmagnetic metal layer or the like sandwiched therebetween and the magnetization direction of which is pinned by an antiferromagnetic layer, and a thickness of 0.5 to 1 nm made of, for example, Al or AlCu A tunnel barrier layer made of a non-magnetic dielectric material in which a metal film of a degree is oxidized by oxygen introduced into the vacuum apparatus or by natural oxidation, and a CoFe having a thickness of about 1 nm, for example, a ferromagnetic material, A magnetization free layer that is composed of a two-layer film of about 4 nm of NiFe or the like and that forms a tunnel exchange coupling with the magnetization fixed layer via the tunnel barrier layer is sequentially laminated. Have a structure.

  The electromagnetic coil element 34 is for perpendicular magnetic recording, and includes a main magnetic pole layer 340, a gap layer 341, a coil layer 342, a coil insulating layer 343, and an auxiliary magnetic pole layer 344. The main magnetic pole layer 340 is a magnetic path for guiding the magnetic flux induced by the coil layer 342 while converging it to the recording layer of the magnetic disk on which writing is performed. Here, the length (thickness) in the layer thickness direction of the end portion 340a on the slider end surface 221 side of the main magnetic pole layer 340 is smaller than the other portions. As a result, it is possible to generate a fine write magnetic field corresponding to an increase in recording density.

  The end portion on the slider end surface 221 side of the auxiliary magnetic pole layer 344 is a trailing shield portion having a wider layer cross section than the other portion of the auxiliary magnetic pole layer 344. The trailing shield portion faces the ABS side end of the main magnetic pole layer 340 via the gap layer. By providing such a trailing shield part, the magnetic field gradient becomes steeper between the end part of the trailing shield part in the vicinity of the slider end surface 221 and the end part of the main magnetic pole layer 340. As a result, the jitter of the signal output is reduced, and the error rate at the time of reading can be reduced.

Here, the main magnetic pole layer 340 has, for example, a total thickness of about 0.01 μm to about 0.5 μm at the end on the ABS side, and a total thickness of other than this end is about 0.5 μm to about 3 μm. 0.0 μm, for example, an alloy composed of any two or three of Ni, Fe and Co formed by using a frame plating method, a sputtering method or the like, or an alloy to which a predetermined element is added based on these alloys Etc. The gap layer 341 is made of, for example, Al ₂ O ₃ (alumina), DLC, or the like formed by using, for example, a sputtering method, a CVD method, or the like with a thickness of about 0.01 μm to about 0.5 μm. The coil layer 342 is made of, for example, Cu or the like having a thickness of about 0.5 μm to about 3 μm and formed using, for example, a frame plating method. The coil insulating layer 343 is composed of, for example, a heat-cured resist layer having a thickness of about 0.1 μm to about 5 μm. The auxiliary magnetic pole layer 344 is, for example, an alloy having a thickness of about 0.5 μm to about 5 μm and formed of any two or three of Ni, Fe, and Co, for example, using a frame plating method, a sputtering method, or the like. Or an alloy containing these as a main component and a predetermined element added.

The waveguide layer 35 is located between the MR effect element 33 and the electromagnetic coil element 34 and extends in parallel with the integration surface 2202. However, the thickness of the waveguide layer 35 toward the slider end surface 221 is near the slider end surface 221. It also has a tapered shape in the vertical direction. The waveguide layer 35 is made of a dielectric material having a refractive index n higher than that of the material forming the covering layer 38, for example, using a sputtering method or the like. For example, when the covering layer 38 is made of SiO ₂ (n = 1.5), the waveguide layer 35 may be made of Al ₂ O ₃ (n = 1.63). Furthermore, when the coating layer 38 is formed of Al ₂ O ₃ (n = 1.63), the waveguide layer 35 includes Ta ₂ O ₅ (n = 2.16), Nb ₂ O ₅ (n = 2.33), TiO (n = 2.3 to 2.55), or TiO ₂ (n = 2.3 to 2.55). By configuring the waveguide layer 35 with such a material, not only the good optical properties of the material itself but also the total reflection conditions at the interface are adjusted, so that the propagation loss of the laser light is reduced and the near field is reduced. Light generation efficiency is improved.

  In FIG. 3A, the near-field light gap part 361 of the near-field light generating part 36 is formed of the same dielectric material as that of the waveguide layer 35. Further, the counter metal layer 360 of the near-field light generator 36, which is not shown in FIG. 3A and shown in FIG. 2, is made of Au, Pd, Pt, Rh, Ir, or any of these. It is made of a conductive material such as an alloy composed of several combinations or an alloy containing Al, Cu or the like.

  The width and layer thickness of the near-field light gap 361 in the track width direction are sufficiently smaller than the wavelength of the incident laser light, and are about 10 nm to about 300 nm and about 10 nm to about 200 nm, respectively. The length of the near-field light gap 361 in the direction perpendicular to the slider end surface 221 is, for example, about 10 to 500 nm. The width in the track width direction at the end face 352 of the waveguide layer 35 is, for example, about 50 to 500 μm.

  3B, on the slider end surface 221, the generation end 361a of the near-field light gap 361 is close to the end 340b of the main magnetic pole layer 340 of the electromagnetic coil element 34, and the leading side of the end 340b. Is located. The shape of the generating end 361a is a regular trapezoid having a short side on the trailing side.

  Here, the near-field light generally has the strongest intensity in the vicinity of the short side on the trailing side having the narrowest width, although it depends on the wavelength of the incident laser light and the shape of the waveguide layer 35. That is, in the heat assist operation for heating the recording layer portion of the magnetic disk, the vicinity of the short side on the trailing side is the main heating operation portion.

  The shape of the end 340b of the main magnetic pole layer 340 is an inverted trapezoid having a long side on the trailing side. That is, the side surface of the end portion 340a of the main magnetic pole layer 340 is provided with a bevel angle so that unnecessary writing or the like is not exerted on the adjacent track due to the influence of the skew angle generated by driving with the rotary actuator. The size of the bevel angle is, for example, about 15 °. Actually, the write magnetic field is mainly generated in the vicinity of the long side on the trailing side, and the width of the write track is determined by the length of the long side.

  According to the arrangement and shape of the generation end 361a of the near-field light gap 361 and the end 340b of the main magnetic pole layer 340 described above, the vicinity of the short side on the trailing side of the generation end 361a which is the main heating action portion However, since it is at a position very close to the end 340b of the main magnetic pole layer, which is the writing portion, immediately after the heat is applied to the recording layer portion of the magnetic disk, the writing magnetic field can be applied with almost no gap. As a result, a stable writing operation by heat assist can be surely executed.

  An inter-element shield layer 48 is formed between the MR effect element 33, the waveguide layer 35, and the near-field light generator 36. The inter-element shield layer 48 plays a role of blocking the MR effect element 33 from the magnetic field generated by the electromagnetic coil element 34 and preventing external noise during reading. Further, a backing coil portion may be further formed between the inter-element shield layer 48 and the waveguide layer 35. The backing coil section generates a magnetic flux that is generated from the electromagnetic coil element 34 and cancels the magnetic flux loop passing through the upper and lower electrode layers of the MR effect element 33, and is a wide adjacent track that is an unnecessary write or erase operation on the magnetic disk. This is intended to suppress the erasing (WAIT) phenomenon. Note that the coil layer 342 is one layer in FIG. 3A, but may be two or more layers or a helical coil.

  Further, the electromagnetic coil element 34 may be used for longitudinal magnetic recording. In this case, instead of the main magnetic pole layer 340 and the auxiliary magnetic pole layer 344, a lower magnetic pole layer and an upper magnetic pole layer are provided, and a write gap sandwiched between ends of the lower magnetic pole layer and the upper magnetic pole layer on the slider end surface 221 side. A layer is provided. Writing is performed by a leakage magnetic field from the position of the write gap layer.

  Next, components of the light source unit 23 of the thin film magnetic head 21 will be described.

In the light source unit 23 of FIG. 3A, reference numeral 230 denotes a unit substrate made of AlTiC (Al ₂ O ₃ —TiC) or the like, and has a bonding surface 2300 bonded to the back surface 2201 of the slider substrate 220. . A propagation layer 41 is provided on an element formation surface 2302 that is one side surface when the adhesive surface 2300 is used as a bottom surface. The propagation layer 41 is provided with a diffractive optical element portion 42 and a prism portion 43. In addition, the laser diode 40 is inclined and installed in a dug 45 having a base 453 formed on the unit substrate 230 and the propagation layer 41.

The propagation layer 41 includes an optical path from the light output end 400 of the laser diode 40 to the end face 410 of the laser diode 40 via the diffractive optical element portion 42 and the prism portion 43. The diffractive optical element 42 is an optical lens having an ordinary curved surface, on which remove the material of the multiple of wavelength for the lens thickness direction, and the 2 ^-n-th power of the height of the wave units (n-1) This is a lens pattern approximated by a staircase structure of individual layers.

As will be described later, when the trench 45 having the base 453 is formed by etching, a material having a lower etching rate than the constituent material of the unit substrate 230 is selected as the constituent material of the propagation layer 41. The For example, when the unit substrate 230 is made of Altic and an ion milling method is used as the etching means, for example, AlN or the like can be selected as the constituent material of the propagation layer 41. In the case of forming a Horikomi 45 having a base 453, for example by machining or the like other means, as the material of the propagation layer _{41, SiO 2, Al 2 O} 3, TiO 2 , etc. it may be selectable.

Further, the diffractive optical element portion 42 will be described in detail later with reference to other drawings. However, the diffractive optical element portion 42 has a refractive index n higher than that of the material forming the propagation layer 41, and is formed by using, for example, a sputtering method. It is made of a dielectric material. For example, when the propagation layer 41 is made of SiO ₂ (n = 1.5) or AlN (n = 1.55), the diffractive optical element unit 42 is made of Al ₂ O ₃ (n = 1.63). It may be formed from. Further, when the propagation layer 41 is made of Al ₂ O ₃ (n = 1.63), the diffractive optical element unit 42 is composed of Ta ₂ O ₅ (n = 2.16), Nb ₂ O ₅ (n = 2.33), TiO (n = 2.3 to 2.55), or TiO ₂ (n = 2.3 to 2.55). Since the diffractive optical element unit 42 has a higher refractive index than the propagation layer 41, the laser light passing through the diffractive optical element unit 42 is adjusted to parallel light or focused light by the lens action based on refraction at the interface. The In addition, the thickness of the propagation layer 41 is, for example, about 30 to 60 μm, and the thickness of the diffractive optical element portion 42 depends on the wavelength of the laser beam as described later, but is, for example, about 0.5 to 5 μm. is there.

The prism portion 43 is formed obliquely with respect to the element formation surface 2302 and changes the traveling direction of the laser light with the layer surface of the propagation layer 41 as the reflection surface 430. For example, when laser beams aligned in parallel by the diffractive optical element unit 42 are incident on the reflecting surface 430 of the prism unit 43 at an incident angle greater than the critical angle, the laser beam is totally reflected by the reflecting surface 430 and is parallel. The traveling direction is changed in the direction of the end face 410 while being aligned. Actually, even if the propagation layer 41 is formed of any one of SiO ₂ (n = 1.5), AlN (n = 1.55), or Al ₂ O ₃ (n = 1.63), the magnetic disk drive Since this has a refractive index larger than the atmosphere (refractive index n is about 1), such total reflection is possible.

Here, a case where the laser light emitted from the laser diode 40 is refracted at the incident side surface 451 and proceeds in a direction further away from the end face 410 of the propagation layer 41 via the diffractive optical element portion 42 will be described. Also in this case, the flat reflection surface 430 is formed in a state inclined by a predetermined angle θ _P so that the side on the end surface 410 side is farthest from the element formation surface 2302, so that The laser beam can be, for example, a laser beam having a direction perpendicular to the bonding surface 2300 (ABS 2200). The predetermined angle θ _P for obtaining such laser light is the installation angle θ _O of the laser diode 40 (the direction of the laser light emitted from the light _output end 400), the refractive index of the atmosphere in the magnetic disk device, And the refractive index of the propagation layer 41 and the like. Incidentally, the installation angle theta _O of the laser diode 40, in order to reliably prevent reflection of return, for example, may be set to about 5 to 15 degrees (deg).

  FIGS. 4A to 4C are schematic views showing the structure of the trench 45 provided with the pedestal 453, the laser diode 40, and the mounting method of the laser diode 40 to the trench 45. FIG.

According to FIG. 4A, the laser diode 40 may have the same structure as that normally used for optical disk storage, for example, an n-electrode 40a, an n-GaAs substrate 40b, an n-InGaAlP cladding layer 40c, a first InGaAlP guide layer 40d, an active layer 40e made of multiple quantum wells (InGaP / InGaAlP), a second InGaAlP guide layer 40f, a p-InGaAlP cladding layer 40g, ^* It has a structure in which an n-GaAs current blocking layer 40h, a p-GaAs contact layer 40i, and a p-electrode 40j are sequentially stacked. Reflective films 50 and 51 made of SiO ₂ , Al ₂ O ₃ or the like for exciting oscillation due to total reflection are formed before and after the cleavage planes of these multilayer structures, and the emitted light from which laser light is emitted At the end 400, an opening is provided at the position of the active layer 40e in one reflective film 50.

The wavelength λ _L of the emitted laser light is, for example, about 600 to 650 nm. However, when providing the near-field light generating part 36 in the slider 22 (FIG. 2), it should be noted that there is an appropriate excitation wavelength according to the metal material of the counter metal layer 360 (FIG. 2). For example, when Au is used for the counter metal layer 360, the wavelength λ _{L of the} laser light is preferably near 600 nm. Further, the excitation wavelength depends not only on the type of the metal material but also on the dimension (length) of the metal material. Even with the same material, when the length of the metal pattern is large, the excitation wavelength tends to be long.

  As described above, the size of the laser diode 40 is, for example, about 250 μm wide × 250 μm long (depth) × 65 μm thick. Here, the width of the laser diode 40 can be reduced to, for example, about 100 μm, with the interval between the opposing ends of the current blocking layer 40 h as a lower limit. However, the length of the laser diode 40 is an amount related to the current density and cannot be made so small. In any case, it is preferable that the laser diode 40 has a considerable size in consideration of handling during mounting.

  In driving the laser diode 40, a power source in the magnetic disk device can be used. Actually, the magnetic disk device usually has a power supply of about 2 V, for example, and has a sufficient voltage for the laser oscillation operation. The power consumption of the laser diode 40 is, for example, about several tens of mW, and can be sufficiently covered by the power supply in the magnetic disk device.

  According to FIG. 4 (B), the dug 45 formed in the unit substrate 230 and the propagation layer 41 includes a pedestal 453, a bottom surface 450, and an incident side surface 451 on which laser light from the laser diode 40 is incident. The side surface 452 is opposite to the incident side surface 451 (opposite the incident side surface 451 in the direction perpendicular to the element formation surface 2302).

  The laser diode 40 is mounted in such a manner that the bottom surface portion on the light emitting end 400 side is placed on the pedestal 453 in such a trench 45, and one electrode forming the bottom surface 401 is 1 of lead-free solder. It is fixed while being electrically connected to the bottom surface 450 of the dug 45 by soldering with the AuSn alloy 52, which is one of them. Here, since the unit substrate 230 is made of, for example, Altic and has conductivity, the laser diode 40 and the drive terminal electrode 440 are electrically connected. In actual fixing, for example, an AuSn alloy deposition film having a thickness of about 1 μm is formed on the bottom surface 450 of the trench 45, and then the laser diode 40 is pressed against the base 453 and the bottom surface 450 with an appropriate force. In addition, heating up to about 200 to 300 ° C. with a hot plate or the like may be performed under a hot air blower. Note that the electrode connected to the bottom surface 450 of the trench 45 may be the n-electrode 40a or the p-electrode 40j. Here, when soldering with the above-described AuSn alloy, the light source unit is heated to a high temperature of about 300 ° C., for example. According to the present invention, the light source unit is manufactured separately from the slider. The magnetic head element in the slider is not affected by this high temperature.

  Further, according to FIG. 4B, the laser diode 40 is installed with the bottom side 4010 opposite to the light emitting end 400 of the laser diode 40 being in contact with the bottom surface 450 of the dug 45. Therefore, the installation position and inclination of the laser diode 40 can be controlled by determining the height of the pedestal 453 and the bottom portion of the base on the pedestal 453. As a result, the installation position and inclination accuracy of the laser diode 40 with respect to the optical system such as the diffractive optical element unit 42 and the prism unit 43 are sufficiently high. Actually, in the alignment of the laser diode 40 in the trench 45, as in the case of aligning the positions of the slider 22 and the light source unit 23, the in-plane direction on the surface having the perpendicular in the track width direction is the track width direction. Although higher accuracy is required, this accuracy is ensured by providing a pedestal 453 having a predetermined upper surface height and determining the bottom surface portion of the laser diode 40 on the pedestal 453.

  Of course, the installation form of the digging and the laser diode is not limited to the above-described embodiment. For example, as shown in FIG. 4C, the laser diode 40 excavates an end side of the upper surface 402 portion opposite to the light emitting end 400, that is, an upper side 4020 opposite to the light emitting end 400. 53 may be placed against the side surface 532 opposite to the incident side surface 531.

  In this case, the installation position and inclination of the laser diode 40 are determined by the position of the pedestal 533 and the height of the upper surface thereof, the position of the base 4010 that contacts the bottom surface 530, and the position of the upper side 4020 that contacts the side surface 532. In practice, the trench 53 including the pedestal 533 can be formed using a photolithographic method, an ion milling method, a reactive ion etching (RIE) method, or the like, as will be described later. The error can be suppressed to be sufficiently small, for example, about ± 0.2 to 1.0 μm. Therefore, since the dimensions of the trench 53 including the pedestal 533 can be controlled with a predetermined accuracy in this way, the laser diode 40 can be installed with a predetermined accuracy with respect to position and inclination. As a result, it is possible to prevent a decrease in the manufacturing yield of the entire head due to an error in the installation position of the laser diode while preventing a decrease in the oscillation characteristics of the laser diode due to the reflected return light.

  The drive terminal electrode 440 is formed on a base layer made of Ta, Ti or the like having a thickness of about 10 nm provided on the unit upper surface 2301 of the unit substrate 230, and has a thickness of about 1 to 3 μm, for example, sputtering. It is composed of layers of Au, Cu, etc. by the method. The drive terminal electrode 441 is formed on a base layer made of Ta, Ti or the like having a thickness of about 10 nm provided on the other non-soldered electrode of the laser diode 40, and has a thickness of 1 It is composed of a layer of Au, Cu or the like by about 3 μm, for example, by sputtering.

  The laser diode 40 and the drive terminal electrodes 440 and 441 described above are naturally not limited to the above-described embodiment. For example, the laser diode 40 uses other semiconductor materials such as a GaAlAs system. Other configurations may be used. Further, it is possible to use other brazing material for soldering the electrodes of the laser diode 40. Furthermore, the drive terminal electrode may be formed by insulating both electrodes of the laser diode 40 from the unit substrate. Furthermore, the laser diode 40 may be formed by epitaxially growing a semiconductor material directly on the unit substrate.

  FIG. 5A is a schematic diagram for explaining the principle of the diffractive optical element unit 42, and FIGS. 5B and 5C are diagrams illustrating the light source unit 23 of the propagation layer 41 including the diffractive optical element unit 42. It is sectional drawing by a surface parallel to the unit upper surface 2301.

First, the principle of the diffractive optical element unit 42 will be described. First, in an optical convex lens having a normal curved surface as in the cross section shown in FIG. 5 (A-1), the wavelength of the laser light in the lens thickness direction as in the cross section shown in FIG. 5 (A-2). Delete multiple materials. Next, as shown in the cross section of FIG. 5A-3, for example, a stepped structure including three layers with the height of a quarter wavelength of the laser light as a unit is illustrated in FIG. 5A-2. Approximate the cross section discretely. In general, the number of layers of the staircase structure is (n−1) when the height of the wavelength is the power of 2− ⁿ . The staircase structure portion having a cross section as shown in FIG. 5A-3 is the diffractive optical element portion 42, which is equivalent to the lens having the cross section shown in FIG. 5A-1. It will have a function.

  According to FIG. 5B, the diffractive optical element unit 42 is formed by appropriately stacking annular first, second, and third diffraction grating layers 420, 421, and 422 stacked in parallel to the integration surface. A laminate pattern having a cross section corresponding to FIG. The thickness of the diffractive optical element portion 42 can be reduced to be equal to or less than the wavelength of the laser light at the center portion thereof. That is, the diffractive optical element portion 42 can be made thin in a planar shape using a thin film microfabrication technique, and thus is very suitable for adjusting the propagation of the light source unit. Note that the diffractive optical element portion 42 in the figure is a case where the height of the quarter wavelength of the laser beam is set as a unit as described above, but it is natural that the diffractive optical element portion 42 has a height of ½ wavelength, 1/8 wavelength or the like. A diffractive optical element portion may be formed in units of thickness.

Here, a method of forming the diffractive optical element portion 42 will be described. In FIG. 5B, on the first propagation layer 41a formed on the element formation surface 2302 of the unit substrate 230 and made of, for example, sputtering using AlN or the like, for example, sputtering or the like. Is used to form a TiO ₂ film having a predetermined thickness. Next, after a predetermined pattern made of NiFe or the like is formed on the TiO ₂ film, for example, etching using an RIE method using a chlorine-based gas is performed using the pattern of NiFe or the like as a mask, and the first diffraction grating Layer 420 is formed. Next, the second diffraction grating layer 421 and the third diffraction grating layer 422 are sequentially stacked to form the diffractive optical element unit 42 by using a method similar to the method of forming the first diffraction grating layer 420. Complete the formation. Thereafter, an AlN film or the like is formed using a sputtering method or the like so as to cover the formed diffractive optical element portion 42, and then this film surface is formed using a chemical mechanical polishing (CMP) method or the like. By flattening to form the second propagation layer 41b, the formation of the propagation layer 41 is completed.

  According to FIG. 5C, the diffractive optical element unit is an optical system in which a first diffractive optical element unit 60 and a second diffractive optical element unit 61 are combined. The first diffractive optical element portion 60 plays a role of adjusting the spread of the laser beam in the track width direction, and extends in a direction perpendicular to the adhesive surface 2300 (FIG. 2) (direction perpendicular to the drawing sheet). It is a pattern. The second diffractive optical element portion 61 plays a role of adjusting the spread of the laser light in the direction perpendicular to the bonding surface 2300 (the direction perpendicular to the paper surface of the drawing), and has a pattern extending in the track width direction. Yes. In this way, by combining two or even three or more diffractive optical element portions, it is possible to obtain laser light whose propagation is adjusted to a desired shape.

  6 (A) to 6 (D) are cross-sectional views corresponding to the cross section taken along the line AA of FIG. 2, showing another embodiment of the light source unit according to the present invention.

  According to FIG. 6A, the diffractive optical element portion 71 is formed on the propagation layer 70, but is not on the optical path connecting the laser diode 40 and the prism portion 43 as in the embodiment of FIG. The laser beam is provided at a position on the optical path that is reached after total reflection at the prism portion 43. Also in this embodiment, the laser light reaching the end surface 700 of the propagation layer 70 can be light aligned in an appropriate direction, for example, a direction perpendicular to the end surface 700.

  According to FIG. 6B, in this embodiment, there is no prism portion as in the embodiment of FIG. 2, and the propagation layer 77 is provided with a grating coupler portion 78 as an optical path changing portion. It has been. The grating coupler unit 78 receives the laser beam emitted from the laser diode 40 and passed through the diffractive optical element unit 42 and aligned in parallel by the light receiving unit 780, and the core layer 781 extends in the traveling direction. Change the direction. Therefore, for example, when the core layer 781 extends parallel to the element formation surface 2302 and reaches the end surface 770 of the propagation layer 77, the laser light whose traveling direction is changed propagates in the core layer 781. Thus, the light is perpendicular to the end face 770 of the propagation layer 77 and aligned in parallel.

  At this time, the laser light is emitted obliquely from the inclined laser diode 40 and further refracted at the incident side surface 451 so that the laser beam has a slightly inclined direction rather than perpendicular to the direction in which the core layer 781 extends (element formation surface 2302). , Enters the light receiving unit 780. Also in this case, by appropriately configuring the light receiving unit 780, the traveling direction of the laser light can be set to the direction in which the core layer 781 extends. As described above, even in the embodiment in which the grating coupler unit is used as the optical path changing unit, it is possible to obtain parallel aligned laser beams having appropriate directions. The configuration of the grating coupler unit will be described later in detail with reference to another drawing.

  According to FIG. 6C, the propagation layer 79 is provided only with a grating coupler 80 as a lens part and an optical path changing part. The grating coupler unit 80 incorporates a structure that has an effect as a collimator in the light receiving unit 800, and after the laser light emitted from the laser diode 40 is received by the light receiving unit 800 of the grating coupler unit 80, The light receiving unit 800 is aligned in parallel, and the traveling direction is further changed to the direction in which the core layer 801 extends. As a result, it is possible to obtain laser beams that are perpendicular to the end face 790 of the propagation layer 79 and aligned in parallel. As described above, even in the embodiment in which the grating coupler unit is used as the lens unit and the optical path changing unit, it is possible to obtain parallel aligned laser beams having appropriate directions without providing any other diffractive optical element unit or the like. It becomes possible.

According to FIG. 6D, the propagation layer 81 has a two-layer structure of a lower propagation layer 810 and an upper propagation layer 811, and the digging 82 is formed extending over the unit substrate 230 and the lower propagation layer 810. ing. The pedestal 823 includes a lower propagation layer 810. In such a configuration, for example, the unit substrate 230 is made of Altic, ion milling is used as an etching means for forming the trench 82, and the constituent material of the lower propagation layer 810 is AlN. This is realized when the constituent material of the upper propagation layer 811 is Al ₂ O ₃ . Here, since the constituent material of the lower propagation layer 810 is AlN having a lower etching rate than that of Altic, the pedestal 823 can be more reliably formed. It is also possible to select other materials according to the height of the material. On the other hand, the constituent material of the upper propagation layer 811 is Al ₂ O ₃ , but when forming the diffractive optical element portion or the like in the upper propagation layer 811, as described above, a material having a higher refractive index than this constituent material is used. Since there are various types, the choice of forming material is expanded.

  FIG. 7 is a cross-sectional view corresponding to the cross section along line AA of FIG.

According to FIG. 7, the grating coupler unit 78 includes a light receiving unit 780, a core layer 781, and first and second cladding layers 782 and 783. The light receiving unit 780 includes first, second, and third light receiving layers 7800, 7801, and 7802, which are predetermined fine pattern layers made of, for example, TiO ₂ (refractive index n = 2.3 to 2.55). The first clad layer 782 is sequentially laminated at a predetermined interval. The core layer 781 is made of, for example, SiO ₂ whose refractive index is adjusted to n = 1.51, and extends in parallel to the element formation surface 2302, and an end 781 a of the core layer 781 is an end surface 770 of the propagation layer 77. Reached vertically. The first and second cladding layers 782 and 783 are made of, for example, SiO ₂ whose refractive index is adjusted to n = 1.46 smaller than that of the core layer, and the light receiving unit 780 and the core layer are formed by both layers. It is formed at a position sandwiching 781. Note that the propagation layer 77 may also be used in place of the first and second cladding layers 782 and 783. In this case, the refractive index of the propagation layer 77 is set to be smaller than the refractive indexes of the light receiving unit 780 and the core layer 781.

  The first, second, and third light receiving layers 7800, 7801, and 7802 of the light receiving unit 780 are patterns having a rectangular cross section that extends in the track width direction (direction perpendicular to the paper surface of the drawing), respectively, and are incident lasers. It has a size and positional relationship according to the incident direction and wavelength of light.

  By using the grating coupler 78 having the above-described configuration as the optical path changing unit, the traveling direction of the laser beam 82 obliquely incident on the light receiving unit 780 is changed, and this laser beam is propagated in the core layer 781. The laser beam 83 can be emitted as a laser beam 83 that is perpendicular to the end surface 770 of the propagation layer 77 and aligned in parallel. Here, the output ratio between the incident laser beam 82 and the emitted laser beam 83 can be increased to about 60 to 80%. In addition, it can be understood that the grating coupler unit is very suitable as an optical path changing unit of the light source unit because it can be made small in a planar shape using a thin film microfabrication technique.

  8A to 8I are schematic views showing an embodiment of a method for manufacturing the light source unit 23 and the thin film magnetic head 21 according to the present invention.

  According to FIG. 8A, first, the dielectric film 90 and the diffractive optical element portion 42 to be the propagation layer 41 are formed on the substrate wafer to be the unit substrate. Here, as the constituent material of the dielectric film 90, a material having a lower etching rate in the etching means used for forming the digging than the constituent material of the unit substrate 230 is selected.

Next, the unit wafer 91 on which the dielectric film 90 and the diffractive optical element unit 42 are formed is cut by bonding to a cutting / separating jig using a resin or the like, and a row in which a plurality of diffractive optical element units 42 are arranged is formed. A unit processing bar 92 including one is cut out. Next, as shown in FIG. 8B, the edge of the dielectric film 90 of the unit processing bar 92 is pressed against a polishing means such as a grindstone at a predetermined angle for polishing. The polished surface at this time becomes the reflecting surface 430. The angle θ _P (FIG. 3) of the reflecting surface 430 is controlled by a predetermined angle to be pressed during polishing.

  Next, as shown in FIG. 8C, after a photoresist pattern 93 is formed on the surface that becomes the unit upper surface 2301 in the unit processing bar 92, a pedestal 453 is provided by an ion milling method or the like, or by an RIE method or the like. A trench 45 is formed. At this time, as described above, since the constituent material of the dielectric film 90 has an etching rate smaller than that of the constituent material of the unit substrate 230, the top surface of the dielectric film 90 is higher than the bottom surface of the etched unit substrate. By having the pedestal 453, the base 453 is formed. In addition, you may perform formation of the digging 45 (FIG.8 (C)) before formation of the reflective surface 430 (FIG.8 (B)).

  Next, as shown in FIG. 8D, the laser diode 40 is mounted on the trench 45 in the unit processing bar 94 in which the trench 45 is formed. At this time, the laser diode 40 is tilted and placed on the pedestal 453 formed with the bottom surface portion on the light exit end 400 side. Thereafter, as shown in FIG. 8E, drive terminal electrodes 440 and 441 for the laser diode 40 are formed. Finally, the unit processing bar 94 is bonded to a cutting jig using resin or the like, grooving processing is performed, and then the cutting processing is performed, so that the unit processing bar 94 is as shown in FIG. The light source unit 23 is separated into chips. Thus, the manufacturing process of the light source unit 23 is completed.

  Here, the characteristic inspection of the laser diode 40 mounted on the light source unit 23 is performed, and only the light source unit 23 in which the mounted laser diode 40 is determined to be non-defective in this inspection is used in the subsequent manufacturing process. Also good. In the characteristic inspection, for example, an inspection probe is brought into contact with the drive terminal electrodes 440 and 441 to actually drive the laser diode 40, and an end surface 410 on the adhesion surface side of the propagation layer 41 using a light receiving element such as a photodiode. It can be implemented by detecting the laser light emitted from.

  Thereafter, as shown in FIG. 8G, the separated light source unit 23 and the already manufactured slider 22 are bonded to each other with the back surface 2201 and the bonding surface 2300 being in contact with each other. At this time, for example, a UV curable resin is applied to the adhesive surface 2300 and / or the back surface 2201, and then the both surfaces are brought into contact with each other for alignment, and then the contact surface portion is irradiated with ultraviolet rays to be bonded and fixed. Good.

  Further, as shown in FIG. 8H, before the unit processing bar 94 is cut and separated, the unit processing bar 94 and the slider processing bar 95 formed in the slider machining process are aligned. Similarly, bonding and fixing may be performed, and then, as shown in FIG. 8 (I), the thin film magnetic heads 21 may be cut and separated. In this case, at least the widths of the slider 22 and the light source unit 23 in the track width direction are set to be the same. Thus, the manufacturing process of the thin film magnetic head 21 is completed.

  Before the unit processing bar 94 and the slider processing bar 95 are fixed, a characteristic inspection of the laser diode 40 mounted on the unit processing bar 94 is performed. In this inspection, all the laser diodes 40 mounted are regarded as non-defective products. Only the determined unit processing bar 94 may be used in the subsequent manufacturing process.

  All the embodiments described above are illustrative of the present invention and are not intended to be limiting, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

1 is a perspective view schematically showing a configuration of a main part in an embodiment of a magnetic disk device and an HGA according to the present invention. 1 is a perspective view showing an embodiment of a thin film magnetic head according to the present invention. 2 is a cross-sectional view taken along the line AA in FIG. 2 schematically showing the configuration of the main part of the thin film magnetic head shown in FIG. 2, and a plan view showing the shape of the end of the magnetic head element and the slider end face of the near-field light generator. It is. It is the schematic which shows the structure of the excavation provided with the base, and the structure of a laser diode, and the mounting method to the excavation of a laser diode. It is the schematic for demonstrating the principle of a diffractive optical element part, and sectional drawing by the surface parallel to the unit upper surface of the light source unit of the propagation layer containing a diffractive optical element part. It is sectional drawing equivalent to the AA sectional view of FIG. 2 which shows other embodiment about the light source unit by this invention. FIG. 3 is a cross-sectional view corresponding to a cross section taken along line AA of FIG. 2, showing a configuration of a grating coupler unit. It is the schematic which shows one Embodiment of the manufacturing method of the light source unit and thin film magnetic head by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic disk 11 Spindle motor 12 Assembly carriage apparatus 13 Recording / reproduction | regeneration and light emission control circuit 14 Drive arm 15 Voice coil motor (VCM)
16 Pivot bearing shaft 17 Head gimbal assembly (HGA)
20 Suspension 200 Load beam 201 Flexure 202 Base plate 203 Wiring member 21 Thin film magnetic head 22 Slider 220 Slider substrate 2200 ABS
2201 Rear surface 2202 Integrated surface 221, 222 Slider end surface 23 Light source unit 230 Unit substrate 2300 Adhesive surface 2301 Unit upper surface 2302 Element formation surface 32 Magnetic head element 33 MR effect element 330 Lower shield layer 332 MR laminate 334 Upper shield layer 34 Electromagnetic coil element 340 Main magnetic pole layer 340a End portion 341 Gap layer 342 Coil layer 343 Coil insulation layer 344 Auxiliary magnetic pole layer 35 Waveguide layer 350 Condensing surface 351 Side surface 352 End surface 36 Near-field light generating portion 360 Opposing metal layer 361 Near-field light gap portion 37 Signal terminal electrode 38 Cover layer 39 Laser light 40 Laser diode 400 Output end 401 Bottom surface 4010 Bottom side 402 Top surface 4020 Top side 41, 70, 77, 79, 81 Propagation layer 410, 411, 700, 770 790 End face 42, 60, 61, 71 Diffractive optical element part 43 Prism part 430 Reflective surface 440, 441 Drive terminal electrode 45, 53, 82 Excavation 450, 530 Bottom face 451, 531 Incident side face 452, 532 Side face 453, 533, 823 Base 48 Inter-element shield layer 50, 51 Reflective film 52 AuSn alloy 78, 80 Grating coupler portion 780, 800 Light receiving portion 781, 801 Core layer 782, 783 Clad layer 810 Lower propagation layer 811 Upper propagation layer 82, 83 Laser light 90 Dielectric Body film 91 Unit wafer 92, 94 Unit processing bar 93 Photoresist pattern 95 Slider processing bar

Claims (17)

The unit substrate having an adhesive surface bonded to the surface opposite to the air bearing surface of the slider, and the adhesive surface of the unit substrate are provided on the element formation surface perpendicular to each other, and the light for heat-assisted magnetic recording is provided. A propagation layer including an optical path; a trench formed on a surface of the unit substrate opposite to the bonding surface; a light source provided in the trench to emit the light; and provided in the propagation layer. And a lens part for adjusting the propagation of the light, and an optical path changing part provided in the propagation layer for directing the light to the end face on the adhesion surface side of the propagation layer,
The light source unit for heat-assisted magnetic recording, wherein the light source is installed at an angle so that light emitted from the light source travels in a direction inclined from a direction perpendicular to the element formation surface.   The light source is inclined and installed such that the bottom surface portion on the light output end side of the light source is further away from the bottom surface of the digging than the bottom surface portion on the side opposite to the light output end of the light source. The light source unit according to claim 1.   The digging is formed on a surface of the unit substrate and the propagation layer opposite to the adhesion surface, and extends to both the unit substrate and the propagation layer, and further to the propagation layer. The light source unit according to claim 2, further comprising a pedestal at a bottom of the portion, wherein the light source is installed in an inclined manner in such a manner that the bottom portion on the light output end side is placed on the pedestal.   The light source unit according to any one of claims 1 to 3, wherein the light source is installed with a base opposite to a light exit end of the light source being placed against a bottom surface of the trench.   4. The light source unit according to claim 1, wherein the light source is installed with an upper side opposite to a light exit end of the light source being placed against a side surface of the trench. 5.   The light source unit according to claim 1, wherein the light source is a laser diode having a light emitting end directed to the propagation layer.   The light source unit according to claim 6, wherein the unit substrate has conductivity, and an electrode forming a bottom surface of the laser diode is electrically connected to the unit substrate.   8. The light source unit according to claim 6, wherein at least one drive terminal electrode for the laser diode is provided on a surface opposite to the bonding surface of the unit substrate.   9. The optical path changing portion according to claim 1, wherein the optical path changing portion is a prism portion formed obliquely with respect to an element formation surface of the unit substrate and having a reflection surface as a layer surface of the propagation layer. The light source unit according to item.   The light source unit according to claim 1, wherein the lens unit is provided at a position on the optical path before the light reaches the optical path changing unit.   The light source unit according to claim 1, wherein the lens unit is a diffractive optical element unit.   12. The light according to claim 1, wherein the light emitted from the end face on the adhesion surface side of the propagation layer is light aligned in parallel and having a direction perpendicular to the adhesion surface. Light source unit.   13. A unit processing bar, wherein each chip after separation becomes the light source unit according to claim 1 by being cut and separated. A slider substrate having the air bearing surface and an integrated surface perpendicular to the air bearing surface; a magnetic head element formed on the integrated surface; and the light receiving surface from its own end surface opposite to the air bearing surface. A slider having a waveguide layer for propagating toward the slider end surface on the side, and a coating layer formed on the integrated surface so as to cover the magnetic head element and the waveguide layer;
The adhesive surface is in contact with the surface opposite to the air bearing surface of the slider, and light emitted from the end surface on the adhesive surface side of the propagation layer propagates through the waveguide layer to the air bearing surface side. A thin film magnetic head comprising: the light source unit according to claim 1, wherein the light source unit is fixed so as to reach an end face of the slider.   The slider is provided at a position in contact with or close to the end surface on the air bearing surface side of the waveguide layer, and generates a near-field light to heat the magnetic recording medium when writing a data signal. 15. The thin film magnetic head according to claim 14, further comprising a near-field light generator having an end reaching the slider end surface on the air bearing surface side.   16. The thin film magnetic head according to claim 14, comprising a support mechanism for supporting the thin film magnetic head, a signal line for the magnetic head element, and a power supply line for the light source. And head gimbal assembly.   At least one head gimbal assembly according to claim 16, controlling at least one magnetic recording medium, and writing and reading operations performed by the thin film magnetic head on the at least one magnetic recording medium; A magnetic disk drive further comprising a recording / reproducing and light emission control circuit for controlling the light emission operation of the light source.

Images