JP2008146750A - Optical member sticking method for semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a satisfied sticking strength as to a semiconductor device by improving adhesion, specially to suppress a stripping to be generated at the mounting operation by a solder, or to suppress a decrease of adhesion when a stress due to a thermal distortion is repeatedly added. <P>SOLUTION: In a resin package seating 1, SiO<SB>2</SB>filler is forcibly exposed as a filling agent containing other than an epoxy resin. Since the SiO<SB>2</SB>filler has an OH group on the surface, a strengthen sticking is obtained by hydrogen bond with an acrylic adhesive 2. The adhesion is improved in such a manner that the SiO<SB>2</SB>filler is exposed by a surface treatment of a resin face of the package seating 1 with a blast process, etc., and the stripping to be generated at the mounting operation by a solder or the decrease of adhesion when the stress due to the thermal distortion is repeatedly added, can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical member bonding method for bonding an optical member to a constituent member in a semiconductor device in which the constituent member is filled with a filler.

A hologram unit that is one of semiconductor devices includes a semiconductor laser element that irradiates a recording medium with laser light, an optical member lens that diffracts reflected light from the recording medium in the laser light emitted from the semiconductor laser element, and a semiconductor A semiconductor laser device including a package base that accommodates a laser element, wherein the package base and the optical member lens are bonded via an adhesive.
JP 2003-77160 A

  By the way, when a hologram lens, which is an optical member, is mounted on a package base via an acrylic adhesive, the adhesion between the acrylic adhesive and the package base mainly composed of an epoxy resin is poor. In addition to not being able to obtain a sufficient adhesion strength after bonding, there has been a problem of a peeling phenomenon that occurs during solder mounting, or a decrease in adhesion when repeated thermal strain stress is applied. In particular, in-vehicle hologram lenses are required to have high quality, and although resistance on the temperature cycle is required, it is difficult to ensure the high resistance.

  The present invention solves the problems of the prior art and provides an optical member bonding method for a semiconductor device that can adhere an optical member to a constituent member in a semiconductor device with good adhesion and can obtain sufficient adhesive strength. Objective.

  In order to achieve the above object, there is provided an optical member bonding method in which an optical member is bonded to the component member in a semiconductor device in which a resin component member is filled with a filler, and the component member is subjected to a blasting process. After the filler is exposed from the surface of the constituent member, the optical member is bonded to the constituent member with an adhesive. With this configuration, the mechanical strength of the resin constituent member is increased in the atmosphere. By forcibly exposing the filler as a filler that is filled to prevent moisture absorption of the filler, the filler is firmly bonded by hydrogen bonding with the acrylic adhesive. For this reason, the adhesiveness of the adhesive part is greatly improved. For example, the peeling phenomenon that occurs at the interface between the resin surface and the adhesive, which may occur during solder mounting, or the adhesiveness when repeated thermal strain stress is applied. The decline in sex is suppressed.

According to the present invention, in a package base that is a component of a semiconductor device, in addition to an epoxy resin that is a molded resin material, for the purpose of preventing mechanical strength and moisture absorption in the atmosphere, for example, a filler and a filler of SiO ₂ based as, by forcibly exposing the filler (SiO _2), since the SiO ₂ has an OH group which is a polar group on the surface thereof, an acrylic-based adhesive It becomes possible to bond firmly by hydrogen bonding with an agent or the like.

  In order to expose the filler, it can be exposed by a surface treatment on the resin surface of a constituent member such as a blasting process, whereby in the present invention, the adhesiveness of the adhesive portion is greatly improved, and there is a concern of occurrence during solder mounting. It is possible to suppress the peeling phenomenon that occurs at the interface between the resin surface of the package base and the adhesive, or the decrease in adhesion when repeated thermal strain stress is applied.

  This makes it possible to improve the quality to the level required for in-vehicle use in a hologram unit that is often applied to in-vehicle use.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a hologram unit, which is an example of a semiconductor device, for explaining an embodiment of an optical member bonding method for a semiconductor device according to the present invention.

  In FIG. 1, a hologram unit 7 has a lens 3, which is an optical member, bonded to a resin surface of a package base 1 with an adhesive 2. The package base 1 is provided with a die pad 6 at the center, and leads 4 are formed on the outer periphery for mounting. A semiconductor laser element 5 is mounted on the die pad 6 by die bonding.

  2A and 2B are explanatory views schematically showing the surface of the package base 1 in the hologram unit 7.

As shown in FIG. 2A, the SiO ₂ filler 11 as a filler is hardly exposed before performing surface treatment such as blast treatment, that is, immediately after molding, when viewed per unit area. On the other hand, when surface treatment such as blast treatment is performed, the SiO ₂ filler 11 as the filler can be exposed on the resin surface of the package base 1 as shown in FIG.

Blasting is generally performed with the expectation of an anchor effect in close contact with the adhesive by removing the release agent remaining on the resin surface, removing dirt, or forcibly forming irregularities. There are many. In addition to this, the present embodiment is novel in that it focuses on the exposure rate of the SiO ₂ filler 11 as a filler and the adhesiveness to the adhesive 2.

In general, silica SiO ₂ is often used as a filler material as a filler, and since the surface has a polar group such as an OH group, strong adhesion to the adhesive 2 is expected. . In particular, when acrylic is used as the adhesive 2, O in the carbonyl group C—O in the adhesive 2 and H of the OH group have high adhesion due to hydrogen bonding. This is probably because the hydrogen H bonded to the atom O having a large electronegativity attracts electrons and is positively charged to develop an electrostatic attractive force. In order to utilize this characteristic, it is possible to improve the adhesion to the adhesive 2 by exposing the SiO ₂ filler 11 as the filler to the resin surface of the package base 1 as described above.

When the SiO ₂ filler 11 as a filler is not exposed, that is, when an acrylic adhesive is mainly adhered from the C element and the H element to the epoxy resin surface, the adhesion in a state having no polar group Therefore, it becomes a bond mainly composed of van der Waals force, it adheres with very low adhesion, and there is a concern that solder heat resistance is weak, such as peeling phenomenon due to heat treatment in mounting . Furthermore, there is a concern about quality such that the resistance to the temperature cycle test which is a repeated thermal strain stress test is extremely weak. When the adhesive 2 is acrylic, the acrylic generally has a large linear expansion coefficient, which is 1 even when compared with the lens 3 that is an optical member used for the hologram unit 7 and the epoxy resin of the package base 1. There is a difference in digits, and the stress generated between materials when a temperature cycle test or the like is performed is expected to be larger than that of a general adhesive, so that a higher adhesion strength is required.

FIG. 3 is an explanatory diagram that graphs the exposure rate of the SiO ₂ filler 11 that is a filler per unit area on the resin surface of the package base 1 depending on the pressure of the blast treatment.

The higher the blasting pressure, the higher the exposure rate of the SiO ₂ filler 11 that is the filler in proportion. When blasting is not performed, the exposure rate per unit area is less than 1%, whereas when blasting is performed, it exceeds 1%, and as the blasting pressure is further increased, the exposure rate tends to increase. It can be seen. As the pressure is increased, the exposure rate is improved and adhesion with the adhesive 2 is expected to be improved. However, it is necessary to verify the influence on other parts.

  For example, when the blast processing is performed on the metal surface of the lead 4 or the die pad 6, the wire bonding property for the inner lead part, the die bonding property to the die pad 6 part is deteriorated, and the lead 4 part is not mounted. It is necessary to carefully consider compatibility with solder, so-called deterioration of solderability.

If the exposure rate per unit area of the SiO ₂ filler 11 as a filler is set to 2% or more by optimizing the blasting conditions, the quality requirement level for in-vehicle use in the adhesion between the package base 1 and the adhesive 2 It is possible to ensure the durability of 1000 cycles of the temperature cycle test (−40 ° C. to 85 ° C.).

As in the present embodiment, when adhered by the adhesive 2, the case of using the acrylic adhesive, by hydrogen bonding with OH groups of the exposed SiO ₂ filler 11 surface is the filler, SiO ₂ filler 11 It has been verified that the adhesive strength is 1.5 times or more than the bond due to intermolecular force when the surface is not exposed.

The mechanism by which the SiO ₂ filler 11 serving as the filler is exposed by the blast treatment is as described above. As a method for managing the exposure rate of the SiO ₂ filler 11 serving as the filler, there is a confirmation method using SEM / EDX. is there.

  However, when the method is applied to an actual mass production process, it can be easily estimated that a great amount of man-hours and time are generated. As a result of examining an alternative management method, the blasting pressure and the metal surface of the die pad 6 are examined. There was a strong correlation with the surface roughness, and the higher the blasting pressure, the larger the surface roughness tended to be almost linear.

  In the present embodiment, by providing a standard for the roughness of the metal surface of the die pad 6 and managing the process, it is possible to manage the die pad 6 with high accuracy and without much man-hours. Since the roughness of the resin surface of the package base 1 is originally molded, it is not flat with respect to the metal surface of the die pad 6, so the variation is large and it is not suitable for process management. However, since various methods can be considered for the blast treatment, the surface roughness (average roughness Ra measured value) of the metal surface of the die pad 6 is determined by changing the conditions of various parameters such as slurry concentration, bead shape, water pressure, blast area area, etc. It is necessary to determine the roughness management standard after verifying the correlation between the blast condition and the blast condition.

As a method of exposing the SiO ₂ filler 11 is filler, in addition to blasting, with fuming nitric acid which can dissolve the resin surface of the package base 1-chemically, chemically SiO ₂ system by etching It is considered possible to expose the SiO ₂ filler 11 by exposing the filler 11 or by physically scraping the resin surface of the package base 1 by several μm.

Furthermore, it is a method in which only the resin component is ashed by O ₂ ashing treatment on the resin surface of the package base 1 to expose the SiO ₂ filler 11 as the filler, or a filler in the resin material used for the package base 1. The effect of improving the adhesiveness is also expected by increasing the content of the SiO ₂ filler 11 to the limit at which the various characteristics of the resin can satisfy the desired characteristics.

In any method, when the exposure rate per unit area of the SiO ₂ filler 11 as a filler is 2% or more, 1000 cycles of a temperature cycle test (−40 ° C. to 85 ° C.) which is a quality requirement level of a vehicle-mounted one. Resistance can be ensured.

Moreover, the adhesion improvement effect by exposing the SiO ₂ filler 11 as the filler does not necessarily need to be the filler filler, and the acrylic resin as the adhesive 2 is applied to the resin surface of the package base 1 in the hologram unit 7. The present invention can be applied to uses other than bonding the lens 3 that is an optical member using the.

  The present invention is applied as a method of adhering an optical member to a component which is a molding resin in various semiconductor devices such as a hologram unit, using an acrylic adhesive, particularly in a hologram unit that is often applied to in-vehicle applications. It is possible and effective to improve the quality to the in-vehicle requirement level.

Sectional drawing of the hologram unit which is an example of the semiconductor device for demonstrating embodiment of the optical member adhesion method with respect to the semiconductor device which concerns on this invention (A), (b) is explanatory drawing which showed the surface of the package base in the hologram unit of this embodiment typically Diagram graph of the exposure rate of SiO ₂ filler per unit area, depending on the pressure of the blast processing in the resin surface of the package base according to the present embodiment

Explanation of symbols

1 Package base 2 Adhesive 3 Optical member (lens)
4 Lead 5 Semiconductor laser element 6 Die pad 7 Hologram unit 11 Filler (SiO ₂ filler)

Claims (5)

  An optical member bonding method in which an optical member is bonded to the component member in a semiconductor device in which a resin component member is filled with a filler, wherein the component member is subjected to a blasting process from a surface of the component member An optical member bonding method for a semiconductor device, comprising: exposing an optical member to the component member with an adhesive after exposing the filler. _{2. The} optical device for a semiconductor device according to claim 1, wherein an etching process, an O ₂ ashing process, and a surface polishing process are employed as the blasting process, and a filler that is a filler is exposed on the surface of the molding resin of the constituent member. Member adhesion method.   3. The method of bonding an optical member to a semiconductor device according to claim 1, wherein the constituent member has a filler content in the molded resin and a filler exposure rate per unit area of the resin surface of 1% or more. 4. The optical member adhesion to a semiconductor device according to claim 1, wherein an acrylic adhesive is used as the adhesive and is hydrogen-bonded to an OH group on the exposed SiO ₂ filler surface. Method.   The blasting pressure for the blasting treatment with respect to the molding resin surface of the constituent member is calculated from the measured value of the average roughness Ra on the metal frame surface incorporated in the pedestal containing the semiconductor element or the die pad surface on which the semiconductor element is mounted. An optical member bonding method for a semiconductor device according to claim 1 or 2.

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