JP2006287085A - Method for manufacturing wiring substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a wiring substrate with high productivity wherein a hole is mechanically formed in a silicon wafer using a drill. <P>SOLUTION: First through-holes 3 having a large diameter are mechanically formed in a silicon wafer 1 using a drill, and the first through-holes are filled with resin material 4. Thereafter, second through-holes 5 having a small diameter are mechanically formed in the resin material using a drill, and wiring that electrically connects the front face and the rear face of the silicon wafer is formed in the second through-holes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wiring board. Specifically, the present invention relates to a wiring board used for connection between electronic components, and particularly to a method for manufacturing a very high density wiring board for mounting a semiconductor chip.

  With recent advances in semiconductor technology, functions mounted on semiconductor chips tend to increase, and the number of input / output terminals of a semiconductor chip has reached several hundred to several thousand pins. On the other hand, semiconductor chip process rules continue to shrink, and the arrangement of input and output terminals is the dominant factor determining the area of the semiconductor chip. For this reason, in order to reduce the cost of the semiconductor chip, the pitch of the input / output terminals tends to be reduced to reduce the area of the semiconductor chip.

  On the other hand, for semiconductor packages, the method of connecting the input / output terminals of a semiconductor chip and external terminals with a gold wire has been generally used, but in recent years, the electrical parasitic component of the gold wire has increased the speed of the semiconductor chip. A semiconductor package with so-called face-down mounting, in which metal protrusions are formed on the input / output terminals of the semiconductor chip, and the semiconductor chip is connected to the wiring board via the metal protrusions, so that the semiconductor package operates at high speed. It has come to be used for chip applications.

  In the case of performing face-down mounting, a wiring pitch equal to or less than the pitch of the input / output terminals of the semiconductor chip is required for the wiring board on which face-down mounting is performed. However, the wiring pitch of a general organic substrate or ceramic substrate is currently limited to about 100 μm, and it is difficult to cope with further narrowing of the input / output terminals of the semiconductor chip.

  Therefore, in recent years, a semiconductor substrate such as a silicon substrate has attracted attention as a substrate for a semiconductor package (for example, see Patent Document 1). By using a semiconductor substrate, it is possible to use a semiconductor process, and because very fine wiring can be formed using the semiconductor process, it is possible to reduce the pitch of input / output terminals of a semiconductor chip. It is possible to respond sufficiently.

JP 2004-79701 A

  By the way, in a substrate on which a semiconductor chip is mounted, an external electrode is generally formed on the surface opposite to the mounting surface of the semiconductor chip. In the case of a semiconductor substrate, formation of a through hole for obtaining conduction between the front and back sides. Is very difficult. For example, an attempt to form a through hole by RIE (Reactive Ion Etching) is not suitable for mass production because it requires a very long etching time. It is also possible to mechanically form a hole with a drill, but it is difficult to form a hole having a diameter of 1 mm or less, and the wall surface of the hole becomes very rough, so that the wall surface of the hole is insulated. Is very difficult.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a wiring board with high productivity.

  In order to achieve the above object, a method of manufacturing a wiring board according to the present invention includes a step of forming a first through hole in a semiconductor substrate, a step of filling the first through hole with an insulating material, Forming a second through hole having a diameter smaller than the diameter of the first through hole in the insulating material filled in the first through hole; and a surface of the semiconductor substrate in the second through hole. Forming a wiring for electrically connecting the back surface.

  Further, the method for manufacturing a wiring board according to the present invention includes a step of forming an insulating layer on the front and back surfaces of a semiconductor substrate, a step of forming a first through hole in the semiconductor substrate, and an insulation to the first through hole. Filling the material, forming a second through hole having a diameter smaller than that of the first through hole in the insulating material filled in the first through hole, and a surface of the insulating layer And a step of forming a conductive layer on the wall surface of the second through hole, and a step of etching the conductive layer formed on the surface of the insulating layer to form a wiring pattern.

  Further, the method for manufacturing a wiring board according to the present invention includes a step of forming an insulating layer on the front and back surfaces of a semiconductor substrate, a step of forming a first through hole in the semiconductor substrate, and an insulation to the first through hole. Filling the material, forming a second through hole having a diameter smaller than the diameter of the first through hole in the insulating material filled in the first through hole, and the second through hole. A step of filling the hole with a conductive material, a step of forming a conductive layer on the surface of the insulating layer, and a step of etching the conductive layer to form a wiring pattern.

  The method for manufacturing a wiring board according to the present invention includes a step of forming an insulating layer on the front and back surfaces of a semiconductor substrate, a step of forming a through hole in the semiconductor substrate, and a step of filling the through hole with an insulating material. Forming a first conductive layer on the back surface of the semiconductor substrate in which the through hole is filled with the insulating material, and having a diameter smaller than the diameter of the through hole in the insulating material filled in the through hole Forming a conductive material in the hole, forming a second conductive layer on the surface of the semiconductor substrate filled with the conductive material in the hole, and the first conductive Forming a wiring pattern by etching the layer and the second conductive layer.

  Here, after the first through hole having a large diameter is formed in the semiconductor substrate, the first through hole is filled with an insulating material such as a resin material, and the insulating material filled in the first through hole has a diameter. By forming the small second through-hole, that is, after forming the first through-hole having a large diameter in the semiconductor substrate in which it is difficult to form the through-hole having a small diameter, the first through-hole has a small diameter. By filling the insulating material capable of forming the through hole and forming the second through hole having a small diameter in the insulating material, the through hole can be formed in the semiconductor substrate with high productivity.

  In the method for manufacturing a wiring board to which the present invention is applied, the through hole having a small diameter can be formed in the semiconductor substrate with high productivity, so that the productivity of the wiring board can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings to facilitate understanding of the present invention.
FIG. 1 is a schematic cross-sectional view for explaining an example of a method for producing a silicon double-sided wiring board, which is an example of a method for producing a wiring board to which the present invention is applied.
In the manufacturing method shown here, first, as shown in FIG. 1A, the insulating layer 2 made of a resin material having a thickness of about 5 to 10 μm is formed on both the front and back surfaces of the silicon wafer 1 by spin coating or printing. Form.

  Here, the insulating layer may be any material as long as the insulation between the semiconductor substrate and a wiring pattern to be described later can be ensured, and is not necessarily a resin material, for example, an inorganic layer such as a silicon nitride film. There may be. Similarly, as long as insulation can be ensured, the film thickness is not necessarily 5 to 10 μm, and the formation method of the insulation film is not limited to the spin coating method or the printing method. In order to ensure the insulation, it is desirable that the thickness is about 5 to 10 μm, and an organic layer such as a resin is more easily 5 to 10 μm than an inorganic layer such as a silicon nitride film. Such a thickness can be formed.

  Next, as shown in FIG.1 (b), the 1st through-hole 3 is formed in the silicon wafer in which the insulating layer was formed by the machining by a drill.

  Here, in the present embodiment, the case where the first through hole is formed by machining with a drill has been described as an example, but the method of forming the first through hole is not necessarily limited to machining with a drill. There is no need, and the first through hole may be formed by laser processing or RIE. In consideration of productivity, it is preferable to form the first through hole by machining with a drill.

  Subsequently, as shown in FIG. 1C, the resin material 4 is completely filled into the first through holes by screen printing, and mechanical polishing is performed after the resin material is filled.

  Here, the screen printing method is not necessarily required as long as the resin material can be filled in the first through hole. The resin material is preferably filled so as to be flush with the surface of the insulating layer. According to the screen printing method, the resin material is formed so as to protrude from the surface of the insulating layer. By polishing the convex portion of the resin material by performing mechanical polishing after filling, the resin material can be flush with the surface of the insulating layer.

  In this embodiment, the first through hole is filled with a resin material as an insulating material. However, the resin material filled in the first through hole is not necessarily a resin material, and any insulating material can be used. May be. In consideration of easy handling and low cost, it is preferable to use a resin material as the insulating material.

  Next, as shown in FIG.1 (d), the 2nd through-hole 5 with a diameter smaller than a 1st through-hole is formed in a resin material by the machining by a drill inside a 1st through-hole. .

  Here, in the present embodiment, as in the case of forming the first through hole, the case where the second through hole is formed by machining with a drill has been described as an example. The forming method is not necessarily limited to machining by a drill, and the second through hole may be formed by laser processing or the like. In consideration of productivity, it is preferable to form the second through hole by machining with a drill, like the first through hole described above. Moreover, when the resin material with which the 1st through-hole was filled is a resin material which has optical resolution, it is also possible to form a 2nd through-hole by exposure process and image development processing.

  Next, as shown in FIG. 1E, after applying a plating catalyst (not shown) on the insulating layers on the front and back surfaces of the silicon wafer and the entire wall surface of the second through hole, chemical copper plating treatment and electrolytic copper are performed. By conducting a plating process, the conductive layer 6 is formed on the insulating layers on the front and back surfaces of the silicon wafer and on the entire wall surface of the second through hole.

  In this embodiment, the resin material is not filled after the conductive layer is formed. However, in consideration of the resist application operation described later, the resin material is formed in the second through-hole by screen printing or the like after the conductive layer is formed. Is more preferable.

  Subsequently, as shown in FIG. 1 (f), an etching resist 7 is formed on the insulating layers on the front and back surfaces of the silicon wafer by using a spin coating method, a printing method, a laminating method, and the like. By performing development processing, the conductive layer is etched to form a wiring pattern 8, and the etching resist is removed to obtain a double-sided wiring board 9 based on a silicon wafer as shown in FIG. Can do.

  In this embodiment, the conductive layer is formed by performing the chemical copper plating process and the electrolytic copper plating process, and then the etching process is performed to form the wiring pattern. However, the wiring pattern is formed by any method. There may be. Specifically, for example, a plating catalyst is provided on the front and back insulating layers of the silicon wafer and the entire wall surface of the second through hole, and after performing only the chemical copper plating treatment, a pattern resist layer is formed, and exposure treatment and After forming a pattern groove in the pattern resist layer by performing development processing, and forming a conductive layer by performing copper plating on the pattern groove formed in the pattern resist layer and the wall surface of the second through hole by electrolytic copper plating processing Alternatively, the wiring pattern may be formed by removing the pattern resist layer and removing the portion of the chemical copper plating covered with the pattern resist layer.

FIG. 2 is a schematic cross-sectional view for explaining another example of the method for producing a silicon double-sided wiring board, which is another example of the method for producing a wiring board to which the present invention is applied.
In the manufacturing method shown here, first, the insulating layer is formed on the front and back surfaces of the silicon wafer, the first through hole is formed, the resin material is filled, and the second through is performed in the same manner as the above-described silicon double-sided wiring board manufacturing method. A hole is formed (see FIG. 2A).

  Next, as shown in FIG. 2B, the second through hole is filled with the conductive paste 10 by screen printing, and mechanical polishing is performed after filling the conductive paste.

  Here, the screen printing method is not necessarily required as long as the conductive paste can be filled in the second through hole. The conductive paste is preferably filled so as to be flush with the surface of the insulating layer. According to the screen printing method, the conductive paste is formed so as to protrude from the surface of the insulating layer. The conductive paste can be made flush with the surface of the insulating layer by polishing the portion of the conductive paste that has become convex after mechanical filling.

Subsequently, as shown in FIG. 2C, the conductive layer 6 is formed by performing a sputtering process and an electrolytic copper plating process on the entire insulating layer on the front and back surfaces of the silicon wafer.
In this embodiment, the electrolytic copper plating process is performed after the sputtering process to ensure the thickness of the wiring layer. However, depending on the thickness of the wiring layer, the conductive layer may be formed only by the sputtering process. .

  Next, as shown in FIG. 2 (d), an etching resist 7 is formed on the front and back insulating layers of the silicon wafer by using a spin coating method, a printing method, a laminating method, and the like. By performing development processing, the conductive layer is etched to form a wiring pattern 8, and the etching resist is removed to obtain a double-sided wiring board 9 based on a silicon wafer as shown in FIG. Can do.

  In this embodiment, the conductive layer is formed by performing the sputtering process and the electrolytic copper plating process, and then the etching process is performed to form the wiring pattern. However, the wiring pattern forming method is any method. Also good. Specifically, for example, a pattern resist layer is formed after performing only a sputtering process on the entire front and back insulating layers of the silicon wafer, and a pattern groove is formed in the pattern resist layer by performing an exposure process and a development process, After forming a conductive layer by applying copper plating to the pattern groove formed in the pattern resist layer by the electrolytic copper plating process, the pattern resist layer was removed, and the part covered by the pattern resist layer was formed by the sputtering process The wiring pattern may be formed by removing the conductive layer.

FIG. 3 is a schematic cross-sectional view for explaining still another example of the method for manufacturing a silicon double-sided wiring board, which is still another example of the method for manufacturing a wiring board to which the present invention is applied.
Here, in the manufacturing method shown, first, an insulating layer is formed on the front and back surfaces of a silicon wafer, a first through hole is formed, and a resin material is filled in the same manner as in the above-described silicon double-sided wiring board manufacturing method (see FIG. 3 (a).)

  Next, as shown in FIG. 3B, the first conductive layer 6a is formed on the insulating layer on the back surface of the silicon wafer by performing a sputtering process and an electrolytic copper plating process.

  Subsequently, as shown in FIG. 3C, a hole 12 having a diameter smaller than that of the first through hole is formed on the inner side of the first through hole by laser processing or the like from the surface side of the silicon wafer. Until the first conductive layer is reached.

Here, in this embodiment, laser processing has been described as an example, but the hole forming method is not limited to laser processing. In addition, when using laser processing, it is possible to form a hole at a higher speed than machining by a drill, and it is possible to form a minute hole compared to machining by a drill.
Further, since it is possible to selectively perforate only the resin material without perforating the first conductive layer, it is preferable to use a carbon dioxide gas laser as the laser. Even other lasers can be selectively drilled by adjusting the intensity of the laser. Furthermore, when the resin material is a photo-resolving resin, it is possible to form holes by exposure processing and development processing.

  Next, as shown in FIG. 3D, the hole is filled with the conductive material 11. As a method for filling the conductive material, for example, a method of performing an electrolytic copper plating process, a method of filling a hole with a conductive paste, or the like can be considered. Here, although the method of filling the hole with the conductive paste is excellent in economic efficiency, the conductive paste has a high resistance value. Therefore, when a higher performance (low resistance) wiring board is required, electrolytic copper plating is used. It is preferable to fill the hole with a conductive material by treatment.

Further, as shown in FIG. 3E, the second conductive layer 6b is formed by performing a sputtering process and an electrolytic copper plating process on the entire surface of the silicon wafer.
In this embodiment, the electrolytic copper plating process is performed after the sputtering process to ensure the thickness of the wiring layer. However, depending on the thickness of the wiring layer, the conductive layer may be formed only by the sputtering process. .

  Next, as shown in FIG. 3F, a spin coating method and a printing method. Etching resist 7 is formed on the front and back insulating layers of the silicon wafer using a laminating method and the like, and the conductive layer is etched by performing exposure processing and development processing on the etching resist to form a wiring pattern 8. By removing the resist, a double-sided wiring board 9 based on a silicon wafer as shown in FIG. 3G can be obtained.

  In this embodiment, the conductive layer is formed by performing the sputtering process and the electrolytic copper plating process, and then the etching process is performed to form the wiring pattern. However, the wiring pattern forming method is any method. The other points are the same as the other example of the method for manufacturing the silicon double-sided wiring board described above.

In the above-described silicon double-sided wiring board manufacturing method, the through-hole (first through-hole) of the silicon wafer is formed larger than the through-hole (second through-hole, hole) for conduction between the front and back of the wiring board. Therefore, it is possible to cope with mechanical processing, and a significant improvement in productivity can be expected as compared with a conventional RIE drilling operation.
In addition, since a through hole (second through hole, hole) having a diameter smaller than 1 mm can be easily formed, a high-density silicon double-sided wiring board is realized.

It is typical sectional drawing for demonstrating an example of the manufacturing method of a silicon double-sided wiring board. It is typical sectional drawing for demonstrating another example of the manufacturing method of a silicon double-sided wiring board. It is typical sectional drawing for demonstrating another example of the manufacturing method of a silicon double-sided wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon wafer 2 Insulating layer 3 1st through-hole 4 Resin material 5 2nd through-hole 6 Conductive layer 6a 1st conductive layer 6b 2nd conductive layer 7 Etching resist 8 Wiring pattern 9 Double-sided wiring board 10 Conductive paste 11 Conductive material 12 hole

Claims (6)

Forming a first through hole in the semiconductor substrate;
Filling the first through hole with an insulating material;
Forming a second through hole having a diameter smaller than the diameter of the first through hole in the insulating material filled in the first through hole;
Forming a wiring for electrically connecting the front and back surfaces of the semiconductor substrate in the second through-hole. A method of manufacturing a wiring substrate, comprising: The method for manufacturing a wiring board according to claim 1, wherein the insulating material is a resin material. Forming an insulating layer on the front and back surfaces of the semiconductor substrate;
Forming a first through hole in the semiconductor substrate;
Filling the first through hole with an insulating material;
Forming a second through hole having a diameter smaller than the diameter of the first through hole in the insulating material filled in the first through hole;
Forming a conductive layer on the surface of the insulating layer and the wall surface of the second through hole;
And a step of performing an etching process on the conductive layer formed on the surface of the insulating layer to form a wiring pattern. Forming an insulating layer on the front and back surfaces of the semiconductor substrate;
Forming a first through hole in the semiconductor substrate;
Filling the first through hole with an insulating material;
Forming a second through hole having a diameter smaller than the diameter of the first through hole in the insulating material filled in the first through hole;
Filling the second through hole with a conductive material;
Forming a conductive layer on the surface of the insulating layer;
And a step of etching the conductive layer to form a wiring pattern. A method of manufacturing a wiring board, comprising: Forming an insulating layer on the front and back surfaces of the semiconductor substrate;
Forming a through hole in the semiconductor substrate;
Filling the through hole with an insulating material;
A first conductive layer is formed on the back surface of the semiconductor substrate in which the insulating material is filled in the through hole, and a hole portion having a diameter smaller than the diameter of the through hole is formed in the insulating material filled in the through hole. Forming, and
Filling the hole with a conductive material;
Forming a second conductive layer on the surface of the semiconductor substrate in which the hole is filled with a conductive material;
A method of forming a wiring pattern by performing an etching process on the first conductive layer and the second conductive layer. The method for manufacturing a wiring board according to claim 5, wherein the hole is filled with a conductive material by electrolytic plating.

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