JP2009176926A - Through wiring substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a through wiring substrate, capable of forming a reform part on a device in which an electrode pad, a wiring layer, and the like have been completed, being applicable to an actual device. <P>SOLUTION: The manufacturing method is for a through wiring substrate 1 that is equipped with a through wiring 7 where fine holes 5 arranged inside a substrate 2 are packed with conductors 6. The manufacturing method comprises at least following steps in order: a step A in which a conductive layer 3 is formed on one surface of the substrate 2; a step B in which laser beam 10 is radiated to the other surface side of the substrate 2 to form a reform part 4 in which one is connected to the conductive layer 3 while the other is communicated with a position different from the conductive layer 3; a step C in which the reform part 4 is removed to form the fine hole 5; and a step D in which the fine hole 5 is packed with the conductors 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a through wiring substrate having through wiring that enables high-density mounting of electronic devices, optical devices, MEMS devices, etc., or SiP (system in package) for systematizing these devices in one package, and It relates to the manufacturing method.

  In recent years, with the enhancement of functions of electronic devices such as mobile phones, electronic devices and the like used for them have been required to have higher speed and higher functions. In order to realize this, not only the speed of the device itself by miniaturization and the like, but also the development of technology for the speed and density of the device package is indispensable.

  As technologies for realizing high-density mounting, three-dimensional mounting in which chips are stacked by mounting fine through electrodes on a chip and system in package (SiP) using a through electrode substrate on which through electrodes are formed have been proposed. Research and development of through-electrode formation technology and through-electrode substrate formation technology for realizing these mounting technologies are being actively conducted. As a technique for forming micropores, a technique for forming micropores by modifying the inside of a substrate with a laser or the like and removing the modified portion by etching has been studied (for example, see Patent Document 1).

However, in putting the above-described through wiring and its manufacturing method into practical use, for example, (1) a method of forming a modified portion and a through wiring for a device that has already been formed with electrode pads, wiring layers, and the like, (2) Formation of through wiring to electrodes that are not resistant to acidic chemicals such as Al pads normally used in devices, (3) Devices that have already been formed with electrode pads, wiring layers, etc. There are some technical problems to be solved, such as fabrication of through wiring at a process temperature not exceeding the heat-resistant temperature, and it has been difficult to realize them unless these are solved.
JP 2006-303360 A

The present invention has been devised in view of such a conventional situation, and it is possible to form a modified portion with respect to a device in which an electrode pad, a wiring layer or the like has already been formed, It is a first object to provide a method of manufacturing a through wiring substrate that can be applied to an actual device.
A second object of the present invention is to provide a through wiring substrate having a through wiring with a higher degree of freedom that can realize miniaturization, high functionality, and high-density mounting of the device itself.

A method for manufacturing a through wiring board according to claim 1 of the present invention is a method for manufacturing a through wiring board having a through wiring in which a fine hole disposed inside the board is filled with a conductor, Step A for forming a conductive layer on one side, laser beam irradiation from the other side of the substrate, one connected to the conductive layer, and the other connected to a position different from the conductive layer. It is characterized in that it comprises at least a process B for forming a mass part, a process C for removing the modified part to form the fine holes, and a process D for filling the fine holes with a conductor.
According to a second aspect of the present invention, there is provided a method for manufacturing a through wiring substrate according to the first aspect of the present invention, in the step B, while recognizing position information using a microscope having a light source in a wavelength region that transmits the substrate. A reforming part is formed.
According to a third aspect of the present invention, there is provided a through wiring substrate manufacturing method according to the first aspect, wherein the conductive layer has a plurality of layers, and at least one layer is made of an acid resistant material.
According to a fourth aspect of the present invention, there is provided a through wiring substrate manufacturing method according to the first aspect, wherein the modified portion is removed by an etching method using an acid solution in the step C.
According to a fifth aspect of the present invention, in the method for manufacturing a through wiring substrate according to the first aspect, in the step D, the conductor is filled at a temperature lower than at least the heat resistant temperature of the substrate and the conductive layer. It is characterized by.
A through wiring board according to a sixth aspect of the present invention is manufactured using the manufacturing method according to any one of the first to fifth aspects.

  In the present invention, a conductive layer is formed on one surface of a substrate, and laser light is irradiated from the other surface side of the substrate, so that an actual device in which a conductive layer such as an electrode pad or a wiring layer is already formed is used. However, the modified portion can be formed. A method of manufacturing a through wiring substrate capable of forming a through wiring having a complicated structure bent or branched inside the substrate by removing the modified portion and then filling the formed fine holes with a conductor. Can be provided.

  Further, in the present invention, by using the manufacturing method according to any one of claims 1 to 5, it has a through wiring having a complicated structure bent or branched inside the substrate, It is possible to provide a through wiring substrate having a through wiring with a higher degree of freedom, which can realize miniaturization, high functionality, and high-density mounting of the device itself.

  Hereinafter, an embodiment of a through wiring board and a manufacturing method thereof according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a configuration example of the through wiring board of the present invention.
The through wiring substrate 1 includes a substrate 2, a conductive layer 3 disposed on one surface 2 a of the substrate 2, and a through wiring 7 in which a conductor 6 is filled in a fine hole 5 disposed inside the substrate 2. It is equipped with.
The through wiring board 1 of the present invention is manufactured by using the manufacturing method of the present invention as described below. Accordingly, the through wiring substrate 1 has the through wiring 7 having a complicated structure bent or branched inside the substrate 2. As a result, the through wiring substrate 1 of the present invention has a through wiring with a higher degree of freedom that can realize miniaturization, high functionality, and high-density mounting of the device itself.

Next, the manufacturing method of the penetration wiring board of the present invention is explained.
FIG. 2 is a schematic cross-sectional view showing the method of manufacturing the through wiring board of the present invention in the order of steps.
In the manufacturing method of the through wiring board according to the present invention, the step A of forming the conductive layer 3 on the one surface 2a of the substrate 2 is irradiated with laser light from the other surface 2b side of the substrate 2, and one is the conductive layer. 3, a process B for forming a modified portion 4 that is connected to a position different from that of the conductive layer 3, and a process C for removing the modified portion 4 to form the micropore 5. And a step D of filling the fine holes 5 with a conductor 6 in order.

In the present invention, the conductive layer 3 is formed on one surface 2a of the substrate 2 and the laser light is irradiated from the other surface 2b side of the substrate 2, so that the conductive layer 3 such as an electrode pad or a wiring layer is already formed. The reforming part 4 can be formed also for the actual device. Thereafter, the modified portion 4 is removed, and the fine hole 5 is filled with the conductor 6, whereby the through wiring 7 having a complicated structure bent or branched inside the substrate 2 can be formed.
Hereinafter, it demonstrates in order of a process. In the following description, specific numerical values and the like are described, but the present invention is not limited to this example.

(1) First, as shown in FIG. 2A, a substrate 2 is prepared, and a conductive layer 3 is formed on one surface 2a of the substrate 2 [step A].
In this embodiment, a glass (quartz) substrate 2 having a thickness of 500 μm is used as the substrate 2 on which the through wiring 7 is formed.
The substrate 2 is not limited to a quartz substrate, and for example, an insulating substrate such as sapphire or silicon (Si) or other component glass substrate containing an alkali component can be used, and its thickness is also 50 μm. It can set suitably to about several mm.

  First, the conductive layer 3 is formed on the substrate 2. The conductive layer 3 may constitute an electrode pad or a wiring layer such as an electric circuit. The method for forming the conductive layer 3 is not particularly limited, but the conductive layer 3 can be formed by vacuum deposition, sputtering, plating, or the like. This can also be formed in a device manufacturing process to which the through wiring 7 is applied.

The conductive layer 3 preferably includes a plurality of layers, and at least one layer is made of an acid resistant material. Thereby, it is possible to prevent the conductive layer 3 from being damaged when the modified portion 4 is etched using an acid solution in the post-process [Step C].
In this embodiment, as the conductive layer 3, an Au (300 nm) / Ti (50 nm) thin film in which titanium (Ti) and gold (Au) having strong acid resistance are both laminated is used, and this is patterned, so that one way Produced an electrode pad of 100 μm.

  The conductive layer 3 can be made of another acid-resistant metal such as Pt, or a conductor other than metal such as polysilicon. In addition, since at least one layer only needs to be made of a material with strong acid resistance, a structure in which the above-mentioned thin film with strong acid resistance and another thin film with low acid resistance, for example, a thin film made of aluminum (Al) or the like are laminated. It may be. Furthermore, the thickness of each layer can also be set appropriately from several tens of nm to about 1 μm.

(2) Next, as shown in FIG. 2B, the laser beam 10 is irradiated from the other surface (the surface opposite to the surface 2a on which the conductive layer 3 is formed) 2b of the substrate 2, Is connected to the conductive layer 3, and the modified portion 4 is connected to the other side at a position different from the conductive layer 3 [Step B].
The modified portion 4 is formed in the substrate 2 by irradiating at least a portion of the substrate 2 where the microhole 5 is to be formed with the laser beam 10. The substrate 2 is modified by irradiating laser light from a surface 2b opposite to the surface 2a on which the conductive layer 3 is formed. As a result, it is possible to modify the interior of the substrate 2 on which the conductive layer 3 such as an electrode pad or a wiring layer already formed exists. Further, it is possible to form the modified portion 4 and thus the fine hole 5 so as to be connected to the conductive layer 3.

  In this embodiment, a femtosecond laser having a wavelength of 800 nm transparent to a quartz substrate, a pulse width of 250 fs, and an average output of 800 mW is used as a light source of the laser beam 10, and the laser is focused on the inside of the substrate 2. The modified portion 4 having a diameter of, for example, several μm to several tens of μm was formed by irradiating the beam and scanning the focal point from the surface 2b side of the substrate 2 toward the inside.

  At this time, the modified portion 4 having various shapes can be formed by controlling the focal point and the substrate position. In the present invention, the modified portion 4 is formed so that one is connected to the conductive layer 3 and the other is open to any surface of the substrate 2. Here, as an example, a crank-shaped reforming section 4A (4) and a Y-shaped reforming section 4B (4) are formed. Thereby, the through wiring 7 can be formed in the conductive layer 3 such as an electrode pad or a wiring layer. As a result, the present invention can be applied to actual devices.

  In addition, using a microscope having a light source (here, halogen light) in a wavelength region that transmits the substrate 2, the position information is recognized by observing the inside of the substrate 2 and the conductive layer 3, and the focus scanning is controlled. However, it is preferable to form the modified portion 4. Thereby, the modification part 4 can be formed so as to be connected to the conductive layer 3.

  The laser beam 10 may have a different wavelength, pulse width, and average output depending on the material to be modified. The modification direction is also focused on the vicinity of the conductive layer 3 in advance. The substrate 2 may be modified from the inside toward the surface.

(3) Next, as shown in FIG. 2 (c), the modified portion 4 is removed to form micropores 5 [step C].
Next, the board | substrate 2 in which the modification part 4 was formed is immersed in the predetermined chemical | medical solution put in the container. Thereby, the modified portion 4 is wet-etched with the chemical solution and removed from the substrate 2. As a result, the micropore 5 is formed in the portion where the modified portion 4 is present. In this example, an acid solution mainly composed of a hydrofluoric acid (HF) solution having a concentration of 10 Wt% was used as the chemical solution. As a result, only the modified portion 4 can be selectively etched, and the micropores 5 can be formed.

  This etching utilizes the phenomenon that the modified portion 4 is etched very quickly (tens of times) compared to the non-modified portion 4, and as a result, the fine holes 5 having a shape caused by the modified portion 4. Can be formed. In the present embodiment, crank-shaped fine holes 5A (5) and Y-shaped fine holes 5B (5) were formed. The hole diameter of the fine holes 5 was 50 μm.

  The chemical solution is not limited to hydrofluoric acid, and for example, a hydrofluoric acid-based mixed acid obtained by adding an appropriate amount of nitric acid or the like to hydrofluoric acid can be used. Further, the hole diameter of the fine hole 5 can be appropriately set from about 10 μm to about 300 μm according to the use of the through wiring 7. Further, the fine holes 5 to be formed may be either those that penetrate the substrate 2 or those that do not penetrate. By the method described above, the fine holes 5 having a three-dimensional free structure can be formed inside the substrate 2.

  At this time, the conductive layer 3 includes a plurality of layers, and at least one layer is made of an acid-resistant material, so that the conductive layer 3 is damaged when the modified portion 4 is etched using an acid solution. Can be prevented. However, the portion having no acid resistance on the substrate 2 can be protected by applying the resist or the like and then performing the etching. Furthermore, the diameter of the micropore 5 can also be set as appropriate from several μm to several hundred μm.

  In addition, about the formation method of the micropore which removes the modified part by etching after modifying a part of the quartz substrate with laser light, for example, “Functional Materials” February 2003, pages 44 to 51, etc. Is disclosed.

(4) Next, as shown in FIG. 2A, the fine holes 5 are filled with a conductor 6 [step D].
By filling the inside of the minute hole 5 with the conductor 6, the through wiring 7 is formed.
In this example, gold tin (Au 80 wt% -Sn 20 wt%) was used as the conductor 6 and filled inside the fine holes 5 by a molten metal filling method. The molten metal filling method is a method in which molten metal is poured into the micro holes 5 using a pressure difference, and the inside of the micro holes 5 having a complicated shape can be filled in a short time with good airtightness. In this embodiment, the crank-shaped through wiring 7A (7) and the Y-shaped through wiring 7B (7) are formed.

  Here, the filling of the conductor 6 is preferably performed at a temperature lower than at least the heat resistance temperature of the substrate 2 and the conductive layer 3. In this embodiment, gold tin (Au 80 wt% -Sn 20 wt%) having a melting point of about 280 ° C. is used as the filling metal, so that the process temperature is lower than the heat resistance temperature of other constituent materials such as Al. Can do. As a result, the through wiring 7 can be formed without causing thermal damage to the constituent members.

  In this example, gold tin (Au—Sn) was used as the conductor 6, but the present invention is not limited to this, and gold-tin alloys having different compositions, tin (Sn), indium (In) In addition, a solder such as a tin lead (Sn—Pb) group, a tin (Sn) group, a lead (Pb) group, a gold (Au) group, an indium (In) group, or an aluminum (Al) group is used. be able to.

  Also, although the molten metal suction method is used as the filling method, the present invention is not limited to this, and depending on the shape of the fine hole 5, the metal filling by the plating method, the filling of the conductive paste by the stamping method, the CVD, etc. Carbon nanotube filling can be utilized.

The conductor 6 does not need to be completely filled in the microhole 5, but a package such as a MEMS device often requires airtightness. Therefore, it is preferable for applications such as the through wiring board 1 and the like. It is preferable that the inside of the fine hole 5 is completely filled.
Through the above steps, the through wiring substrate 1 as shown in FIG. 1 can be obtained.

  According to the method for manufacturing a through wiring board of the present invention as described above, even a device in which a conductive layer 3 such as an electrode pad or a wiring layer has already been formed is complicatedly bent or branched inside the board 2. The through wiring 7 having a structure can be formed.

  Thereby, the through wiring board 1 of the present invention manufactured by the manufacturing method of the present invention has a through wiring 7 with a higher degree of freedom that can realize miniaturization, high functionality, and high density mounting of the device itself. It will have.

  In application to an actual device, it is possible to provide a small semiconductor package that can be flip-chip mounted on a printed circuit board or the like by forming bumps such as solder so as to be electrically connected to the through wiring 7. It becomes possible. FIG. 3 shows a schematic cross-sectional view when a solder bump 8 electrically connected to the through wiring 7 is formed as an example.

  As mentioned above, although the penetration wiring board and its manufacturing method of this invention were demonstrated, this invention is not limited to this, In the range which does not deviate from the meaning of invention, it can change suitably.

  The present invention can be widely applied to a through wiring substrate having the through wiring 7 and a manufacturing method thereof.

Sectional drawing which shows an example of the penetration wiring board which concerns on this invention. Sectional drawing which shows an example of the manufacturing method of the penetration wiring board shown in FIG. 1 in order of a process. Sectional drawing which shows the state in which the solder bump was formed in the penetration wiring board shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Through wiring board, 2 Substrate, 3 Conductive layer, 4 Modified part, 5 Fine hole, 6 Conductor, 7 Through wiring, 8 Solder bump, 10 Laser light.

Claims (6)

A method of manufacturing a through wiring board having a through wiring in which conductors are filled in fine holes arranged inside the board,
Forming a conductive layer on one surface of the substrate;
Irradiating a laser beam from the other surface side of the substrate, one of which is connected to the conductive layer, and the other is a step B of forming a modified portion connected to a position different from the conductive layer;
Removing the modified portion and forming the micropores; and
And a step D of filling the fine holes with a conductor at least in order.   2. The through wiring substrate according to claim 1, wherein in the step B, the modified portion is formed while recognizing position information using a microscope having a light source in a wavelength region that transmits the substrate. Method.   The method for manufacturing a through wiring substrate according to claim 1, wherein the conductive layer includes a plurality of layers, and at least one layer is made of an acid resistant material.   The method for manufacturing a through wiring substrate according to claim 1, wherein in the step C, the modified portion is removed using an etching method using an acid solution.   2. The method of manufacturing a through wiring substrate according to claim 1, wherein in the step D, the conductor is filled at a temperature lower than at least a heat resistant temperature of the substrate and the conductive layer.   A through wiring substrate manufactured using the manufacturing method according to claim 1.

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