JP2007067031A - Method of manufacturing wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of efficiently and inexpensively manufacturing a wiring board having a through conductor wiring. <P>SOLUTION: This method has a substrate preparing process of preparing a substrate in which at least a substrate surface and a through hole internal surface are made of an insulator; conductive supporter preparing process of preparing a conductive supporter; photoresist layer forming process of forming a photoresist layer on the one side surface of the substrate or the conductive supporter; exposure processing process of executing exposure processing for the photoresist layer; substrate-conductive supporter joining process of joining the substrate and the conductive supporter via the photoresist layer; conductive supporter exposing process of executing development processing and removing the photoresist layer positioned on the lower side of a through hole opening of the substrate to expose one part of the conductive supporter; and metal film forming process of forming a metal film on the through hole by an electroplating method using the conductive supporter as a cathode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wiring board, and more particularly, to a method for manufacturing a wiring board that can efficiently manufacture a wiring board having a through conductor wiring used for three-dimensional mounting.

  Conventionally, in research and development of semiconductor systems, a technology that can realize high-speed mounting has attracted attention. As a technique for achieving high-speed mounting of a semiconductor system, a three-dimensional mounting technique is known in which a plurality of substrates on which semiconductor circuits are formed are stacked and connected in a three-dimensional direction.

  By using this three-dimensional mounting technology to create a semiconductor system, not only will the degree of freedom of wiring design be expanded, but the length of the wiring can be shortened compared to the conventional planar system LSI, resulting in higher frequencies. Correspondence becomes possible.

  In order to produce a substrate having such a through-conductor wiring, after forming a non-through hole, a metal film is formed by a so-called bottom-up plating method, or as reported by Kondo et al. A method is known in which a hole is formed and then attached to a conductive substrate and then performed by a through mask plating method. The latter process is significantly shortened compared to the former.

  The outline of the latter technique proposed by Kondo et al. Is as follows. First, a substrate provided with a through hole is bonded to a copper foil with an adhesive using a vacuum laminator. Then, the adhesive in the through hole portion is selectively removed by dry etching. Electroplating with copper foil as the cathode while the bottom is conductive only causes the plating to deposit from only the bottom, so that voids and seams are not easily formed, and copper is deposited inside the through hole at high speed with simple plating. it can. Thereafter, polishing is performed from the back surface, and unnecessary portions including the copper foil are removed.

  However, the above method requires a step of selectively removing the adhesive in the through hole portion by dry etching. Dry etching has a high apparatus cost and a long processing time. For this reason, there exists a possibility of causing the deterioration of process time and process cost. Further, since dry etching is isotropic etching, an overhang is generated in the resin layer, so that an electroplating film is not sufficiently formed in that portion, and a so-called nest may be formed. In addition, when copper foil is used as a conductive support for electroplating, the adhesive strength is high with the copper plating film inside the deposited through-hole, so the substrate and the copper foil are integrated, and the separation is Have difficulty. For this reason, a polishing process from the back surface is also indispensable.

Proceedings of the 13th Microelectronics Symposium, published by Japan Institute of Electronics Packaging, October 16, 2003, pp. 260-263

  The present invention was devised in such an actual state, and an object of the present invention is to provide a method capable of efficiently and inexpensively manufacturing a wiring board having a through conductor wiring.

  In order to solve such a problem, the present invention provides a substrate having a through-hole, wherein the substrate is an insulator at least on the surface and the inner surface of the through-hole is an insulator. A method of manufacturing a wiring board in which a metal film is formed by electroplating, which comprises a substrate having a through hole, at least a substrate surface and an inner surface of the through hole being an insulator. Substrate preparation step, conductive support preparation step for preparing a conductive support, a photoresist layer formation step for forming a photoresist layer on one surface of the substrate or the conductive support, and an exposure process for the photoresist layer An exposure processing step, a substrate-conductive support bonding step for bonding the substrate and the conductive support through a photoresist layer, and a development process, and are positioned below the through-hole opening of the substrate. Fo Removing the resist layer to expose a part of the conductive support; and a metal film forming step of forming a metal in the through hole by electroplating using the conductive support as a cathode; It is comprised so that it may have.

  As a preferred embodiment of the present invention, the photoresist layer in the photoresist layer forming step is composed of a negative resist.

  As a preferred embodiment of the present invention, the photoresist layer in the exposure processing step is exposed in a closed loop shape around the periphery of the through hole.

  As a preferred embodiment of the present invention, the inner path portion of the closed path exposed in the exposure processing step is substantially the same size as the size of the through hole.

  Further, as a preferred aspect of the present invention, closed-circuit exposure along the periphery of the through hole in the exposure processing step is performed through a photomask.

  As a preferred embodiment of the present invention, the photoresist layer in the photoresist layer forming step is composed of a positive resist, the exposure processing step is performed after the substrate-conductive support bonding step, and the exposure processing step. The exposure process is performed from above the substrate (through hole opening side) using the substrate as a mask.

  As a preferred embodiment of the present invention, the photoresist layer in the exposure processing step is exposed to a size substantially the same as the size of the through hole.

  As a preferred embodiment of the present invention, the photoresist layer is composed of a dry film resist.

  As a preferred embodiment of the present invention, at least the surface of the conductive support is composed of stainless steel, titanium, aluminum, chromium, or a metal plate mainly composed of any of the above metals.

  According to the method for manufacturing a wiring board of the present invention, since a photoresist layer having a through hole with high accuracy by photolithography is formed, plating defects are unlikely to occur. Further, it can be formed in a short time by a simple process with an inexpensive facility.

  Moreover, since the electroconductive support body used as a plating cathode and a plating film peel easily, a grinding | polishing process is unnecessary and it can form in a further short time. Furthermore, since bumps can be formed simultaneously, it can be formed in a shorter time.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  The present invention is a method for manufacturing a wiring board in which a metal film is formed by electroplating in a through hole of a substrate having at least a surface thereof made of an insulator and an inner surface of the through hole being an insulator.

  Such a method of manufacturing a wiring board includes: (1) a substrate preparation step of preparing a substrate having a through hole, at least the substrate surface and the inner surface of the through hole being an insulator; and (2) a conductive support. (3) a photoresist layer forming step for forming a photoresist layer on one surface of the substrate or the conductive support; and (4) an exposure process for exposing the photoresist layer. A processing step; (5) a substrate-conductive support bonding step in which the substrate and the conductive support are bonded via a photoresist layer; and (6) performing a development process under the through hole opening of the substrate. Removing the photoresist layer located on the side to expose a part of the conductive support; and (7) forming a metal in the through hole by electroplating using the conductive support as a cathode. Forming a metal film, Configured to have.

FIG. 1 sequentially shows a process chart over time in the first embodiment of the present invention.
Hereinafter, each step will be described in detail.

(1) Substrate Preparation Step First, a substrate 10 having a through hole 15 is prepared as shown in FIG. The hole shape (horizontal cross-sectional shape in the drawing) of the through hole 15 may be an ellipse or various polygons as well as a circle and a regular square.

  A method for opening the through hole 15 in the substrate 10 may be a known method. For example, a method of forming a through hole 15 by reactive ion etching after providing an etching mask on one side of a silicon substrate can be exemplified. Other known penetration methods such as mechanical drilling, laser processing, wet etching, etc. can also be used.

  The substrate 10 according to the present invention is configured such that both the substrate surface 10a and the inner surface 15a of the through hole 15 are insulators. In order to form such an insulator structure, if the substrate 10 itself is made of an insulator, it can be easily realized simply by drilling. On the other hand, when the material of the substrate 10 itself has conductivity, a process of forming an insulating layer on the surface of the substrate and in the through hole is performed by a known method. For example, when the substrate 10 is silicon, a silicon oxide insulator film is formed on the surface of the substrate and in the through hole by a thermal oxidation method. Such an insulator film can also be formed by an anodic oxidation method or coating.

  FIG. 1A illustrates a substrate 10 in which an electrically conductive substrate is used and an insulator is formed on the surface 10 a and the inner surface 15 a of the through hole 15. In the following description of the process, the explanation is made in the case where this type of substrate 10 is used.

(2) Conductive support body preparation process The conductive support body 40 is prepared.

  The conductive support 40 is bonded to the substrate 10 via a photoresist layer in a substrate-conductive support bonding process described later (see FIG. 1C).

  The conductive support 40 is preferably a metal plate having at least the surface thereof made mainly of stainless steel, titanium, aluminum, chromium, or the metal. In particular, it is desirable to select a material with low adhesion strength in relation to the electroplating film described later.

(3) Photoresist Layer Forming Step As shown in FIG. 1B, a photoresist layer 20 is formed on one surface (the lower flat surface in FIG. 1B) of the substrate 10.

  The photoresist in the present invention means not only resins having a sensitivity to ultraviolet rays or visible rays having a wavelength of 300 to 500 nm, but also general resins that can be reacted and patterned by far ultraviolet rays, X-rays, electron beams, and the like. . A liquid resist can also be used, but since it is necessary to form it so as to cover the end of the through-hole 15, it is preferable to use a film-like dry film resist having a certain degree of adhesiveness. When a dry film resist is used, it is preferably bonded to the substrate 10 in a heated state.

  There are usually two types of dry film resists: negative resists and positive resists. In the process shown in FIG. 1, a negative resist is used, and in the process shown in FIG. 2 described later, a positive resist is used.

(4) Exposure Process Step Next, an exposure process is performed on a predetermined portion of the photoresist layer 20. That is, as shown in the overall view of FIG. 1B, an exposure process is performed on a predetermined portion of the photoresist layer 20 through a separately prepared photomask 30.

  The exposure pattern shown in FIG. 1B is exposed in a closed loop shape around the end 15 e of the through hole 15. The closed circuit shape is constituted by a band-shaped closed circuit having a substantially constant width. For example, if the shape of the end portion 15e of the through hole 15 is circular, exposure is performed so as to form a ring-shaped belt-like closed circuit along this shape.

  In the present invention, if a desired pattern is formed in the photoresist layer 20, the object of the invention is achieved. For this reason, the exposure pattern by the photomask 30 does not have to be substantially the same as the hole diameter of the end 15e of the through hole 15, and can be large or small depending on the element design. However, in order to prevent the formation of a nest during plating film formation performed in the subsequent process, the inner path portion of the closed circuit exposed in this exposure processing process is the size of the through hole 15, that is, the through hole 15. It is desirable that the size is substantially the same as the size of the end portion 15e. More specifically, it may be within plus or minus 200 μm, preferably within 50 μm with respect to the pore diameter.

  In particular, in the process shown in FIG. 1, it is preferable to use a negative resist as described above, and to expose on a ring centering on the through hole if the through hole is circular. This is because the negative resist undergoes a polymerization reaction upon exposure, and the adhesive strength between the support and the exposed photoresist layer is reduced.

  When all the portions other than the peripheral portion of the through hole 15 are exposed, almost the entire bonding portion undergoes a polymerization reaction, and therefore, the conductive support 40 and the substrate 10 to be bonded through the photoresist layer 20 in a later step. Peeling may occur between the two. By providing an exposed portion in a donut shape only around the through-hole 15, the resist in the through-hole 15 portion is dissolved by the developer used in the subsequent development processing, but the exposed portion 22 exists around the periphery ( The dissolution reaction does not proceed beyond that (see FIG. 1C). In addition, since the exposed photoresist is a part, the adhesive strength is still maintained between the conductive support and the substrate, and peeling does not easily occur.

  The term donut shape used in the present invention does not mean only a double ring state, as is clear from the above-mentioned meaning, but a square or polygonal 2 can be used as long as the effect of the present invention is achieved. A pattern in a heavy state or a pattern state in which the inner periphery is circular and the outer periphery is polygonal is also included.

(5) Substrate-conductive support bonding step A substrate-conductive support bonding step for bonding the substrate 10 and the conductive support 40 via the photoresist layer 20 is performed after the exposure processing step. .

  That is, as shown in FIG. 1C, an operation of bonding the substrate 10 and the conductive support 40 together through the photoresist layer 20 is performed. As the bonding operation, a known method such as a so-called thermocompression bonding method or a vacuum laminating method can be used.

  The donut-shaped dot region 22 (grained region 22) in the photoresist layer in FIG. 1C has undergone a polymerization reaction due to the exposure process as described above, and the developer in the post-development development process It shows that it is no longer dissolved.

  As described above, the conductive support 40 is preferably a metal plate having at least the surface thereof made of stainless steel, titanium, aluminum, chromium, or the metal as a main component. In particular, it is desirable to select a material with low adhesion strength in relation to the electroplating film described later.

(6) Conductive Support Exposure Step Next, the development of the conductive support is performed to remove the photoresist layer located below the through-hole opening of the substrate and expose a part of the conductive support. A process is performed.

  That is, after the substrate 10 and the conductive support 40 are bonded together via the photoresist layer 20, development is performed so that the developer enters the through hole 15. As a result, only the resist 21 (see FIG. 1C) at the bottom of the through-hole 15 that is not exposed to light and is in contact with the developer dissolves, and a part 41 of the conductive support (see FIG. 1D). ) Is exposed to the state shown in FIG.

  As shown in FIG. 1D, in the present invention, since the photoresist is patterned by resist exposure using photolithography, the resist side surface 22a after development is substantially vertical, which is an example of a comparative method. There is no overhang such as patterning by the etching process. For this reason, the patterning accuracy in the present invention is extremely high.

(7) Metal film forming step Next, a metal film forming step is performed in which a metal is formed in the through hole by electroplating using the bonded conductive support 40 as a cathode.

  That is, as shown in FIG. 1E, by performing electroplating using the conductive support 40 as a cathode, a metal 50 as a conductor is formed on the inside of the through hole and the portion 21 where the resist is removed. And filled. The conductor metal 50 is preferably copper, gold, platinum, nickel, tin, or an alloy containing these as a main component. It is particularly preferable to use copper. This is because it is inexpensive and has low resistance.

  Next, the resist 20 is stripped from the substrate 10 using a stripping solution or the like. As a result, as shown in FIG. 1F, the conductive support 40 is removed from the substrate 10, and the wiring substrate 1 is completed.

  In the present invention, since a photoresist layer having a through hole with high accuracy by photolithography is formed, plating defects do not occur. Moreover, since the electroconductive support body 40 used as a plating cathode and a plating film (metal 50) peel easily, a grinding | polishing process is unnecessary and it can form in a further short time.

  Further, in a preferred embodiment of the present invention, bumps 50a and 50b that are convex from the surface of the wiring board are provided on one or both sides of the metal 50 filled in the through hole 15 (FIG. 1F). reference). This is because the plating film (metal 50) is also deposited on the patterned lower portion 50a of the resist on the lower surface of the substrate, and the upper surface of the substrate is convex with a so-called mushroom bump shape 50b. Because it is. If necessary, the surface can be polished to obtain a bump base (lower structure for bump formation) with a smooth surface having a uniform height. Further, a barrier metal such as nickel can be formed on the bump, and a solder bump can be formed.

<Modification of First Embodiment>
As described above, in the first embodiment based on the flow of FIG. 1, first, a photoresist layer 20 is formed on one surface of the substrate 10, and a predetermined exposure process is performed on the photoresist layer 20. The substrate 10 and the conductive support 40 are bonded via the resist layer 20.

  However, in addition to this mode, the following procedure may be used to change the joining order. That is, first, a photoresist layer 20 is first formed on one surface of the conductive support 40, a predetermined exposure process is performed on the photoresist layer 20, and then the substrate 10 is interposed via the photoresist layer 20. And the conductive support 40 may be bonded together. As a result, the same state as in FIG. 1C is formed from either approach. However, in the latter case, for example, it is necessary to perform alignment between the conductive support 40 after exposure and the substrate 10 using an alignment mark or the like.

  Next, an example of the second embodiment of the present invention will be described with reference to FIG.

  Also in this manufacturing method, as in the first embodiment described above, the substrate and the conductive support are joined using a photoresist, and the photoresist is exposed and developed to develop a photo under the substrate through hole. A constituent requirement for dissolving and removing the resist layer is provided.

  However, in the embodiment shown in FIG. 2, the positive resist is used and the exposure process can be performed by using the substrate having a through hole as a photomask without using a separately prepared photomask. And different.

Hereinafter, each step will be described in detail.
(2-1) Substrate Preparation Step First, the substrate 10 having the through holes 15 is prepared as shown in FIG.
The details of the process are the same as those described in the case of the embodiment of FIG.

(2-2) Conductive support body preparation process The conductive support body 40 is prepared.
The conductive support 40 is bonded to the substrate 10 through a photoresist layer in a substrate-conductive support bonding process described later (see FIG. 2B).

  The details of the process are the same as those described in the case of the first embodiment, and a detailed description thereof is omitted here.

(2-3) Photoresist Layer Formation Step Next, as shown in FIG. 2B, a photoresist layer 20 is formed on one surface of the substrate 10 (the lower plane in FIG. 2B). .

  The photoresist in the present invention is defined similarly as described above. A liquid resist can also be used, but since it is necessary to form it so as to cover the end of the through-hole 15, it is preferable to use a film-like dry film resist having a certain degree of adhesiveness. When a dry film resist is used, it is preferably bonded to the substrate 10 in a heated state.

  In the process shown in FIG. 2, a positive resist in which the resist in the exposed portion is dissolved and removed with a developer is used.

(2-4) Substrate-conductive support bonding step Next, a substrate-conductive support bonding step for bonding the substrate 10 and the conductive support 40 via the photoresist layer 20 is performed.

  That is, as shown in FIG. 2B, an operation of bonding the substrate 10 and the conductive support 40 through the photoresist layer 20 is performed. As the bonding operation, a known method such as a so-called thermocompression bonding method or a vacuum laminating method can be used.

  As described above, the conductive support 40 is preferably a metal plate having at least the surface thereof made of stainless steel, titanium, aluminum, chromium, or the metal as a main component. In particular, it is desirable to select a material with low adhesion strength in relation to the electroplating film described later.

(2-5) Exposure Process Step Next, an exposure process is performed on a predetermined portion of the photoresist layer 20. That is, as shown in the overall view of FIG. 2B, the exposure process is performed from above the substrate (through hole opening side) using the substrate as a mask. Accordingly, the photoresist layer is exposed to a size substantially the same as the size of the through hole. The dot area 21 ′ (grain area 21 ′) in the photoresist layer in FIG. 2B indicates that the part is dissolved in the developer in the post-development development process by the exposure process. ing.

(2-6) Conductive Support Exposure Step Next, the conductive support is exposed to expose a part of the conductive support by performing development processing and removing the photoresist layer located below the through hole opening of the substrate. A body exposure process is performed.

  That is, development is performed such that the developer enters the through hole 15. Then, only the resist 21 '(see FIG. 2B) at the bottom of the through hole 15 that has been exposed and is in contact with the developer is dissolved, and a part 41 of the conductive support (FIG. 2C) is dissolved. 2) is exposed, and the state shown in FIG.

  As shown in FIG. 2C, in the present invention, since the photoresist is patterned by resist exposure using photolithography, the side surface 20a of the resist after development is substantially vertical. There is no overhang such as patterning by the etching process. For this reason, the patterning accuracy in the present invention is extremely high.

(2-7) Metal Film Formation Step Next, a metal film formation step is performed in which a metal is formed in the through hole by electroplating using the bonded conductive support 40 as a cathode.

  That is, as shown in FIG. 2D, by performing electroplating using the conductive support 40 as a cathode, the metal 50 as a conductor is formed in the inside of the through hole and in the portion 21 'from which the resist has been removed. Filmed and filled. The conductor metal 50 is preferably copper, gold, platinum, nickel, tin, or an alloy containing these as a main component. It is particularly preferable to use copper. This is because it is inexpensive and has low resistance.

  Next, the resist 20 is stripped from the substrate 10 using a stripping solution or the like. As a result, as shown in FIG. 2E, the conductive support 40 is removed from the substrate 10, and the wiring substrate 1 is completed. In the present invention, since a photoresist layer having a through hole with high accuracy by photolithography is formed, plating defects do not occur. Moreover, since the electroconductive support body 40 used as a plating cathode and a plating film (metal 50) peel easily, a grinding | polishing process is unnecessary and it can form in a further short time.

  Further, in a preferred embodiment of the present invention, as described above, bumps 50a and 50b that are convex from the surface of the wiring board are provided on one side or both sides of the metal 50 filled in the through-hole 15 (see FIG. 2 (E)). This is because the plating film (metal 50) is also deposited on the resist patterned portion 50a on the lower surface of the substrate, and the upper surface of the substrate is convex with a so-called mushroom bump shape 50b. Because. If necessary, the surface can be polished to obtain a bump base (lower structure for bump formation) with a smooth surface having a uniform height. Further, a barrier metal such as nickel can be formed on the bump, and a solder bump can be formed.

<Modification of Second Embodiment>
As described above, in the second embodiment based on the flow of FIG. 2, first, the photoresist layer 20 is formed on one surface of the substrate 10, and the substrate 10 and the conductive support 40 are interposed via the photoresist layer 20. After that, the photoresist layer 20 is subjected to a predetermined exposure process. However, the following procedure may be used to change the joining order separately from this embodiment. That is, first, a photoresist layer 20 is first formed on the surface of one side of the conductive support 40, the substrate 10 and the conductive support 40 are bonded via the photoresist layer 20, and then, A predetermined exposure process may be performed on the photoresist layer 20. As a result, the same state as in FIG. 2B is formed from either approach. In the modification of the second embodiment, unlike the modification of the first embodiment, for example, alignment using an alignment mark or the like is not required.

  When DFR is used as the photoresist layer 20, the photoresist layer 20 is sandwiched between the substrate 10 and the conductive support 40, and the substrate 10 and the conductive support 40 are bonded to the photoresist layer 20 at the same time. It is also possible to do. That is, a photoresist layer forming step of forming a photoresist layer on one surface of the substrate or the conductive support, and a substrate-conductive support bonding in which the substrate and the conductive support are bonded via the photoresist layer. The process is performed simultaneously.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

[Example 1]
A resist mask for pattern formation was formed as an etching mask on a silicon substrate having a thickness of 150 μm and a diameter of 4 inches. The etching mask was a pattern in which a large number of 50 μm diameter circular patterns were arranged in a matrix in the X and Y directions at a pitch of 170 μm. A polyimide solution was applied to the entire back surface of the substrate to form an etching stop layer.

  Next, the exposed portion of the substrate was etched by a deep RIE method to form a through hole having a diameter of 50 μm. Thereafter, the substrate was treated at 1100 ° C. for 5 hours in a diffusion furnace to form a silicon oxide insulating layer having a thickness of 0.5 μm on the substrate surface and the inner surface of the through hole.

  Next, a negative DFR (dry film resist) having a thickness of 15 μm was pressure-bonded to the silicon substrate at 110 ° C. Separately, an exposure process was performed through a photomask in which a prepared donut-shaped portion having an inner diameter of 55 μm and an outer diameter of 65 μm was arranged in a matrix in the X and Y directions at a pitch of 170 μm.

Next, a stainless steel support body having a thickness of 0.05 mm and a diameter of 4 inches was separately prepared, treated at 120 ° C. in a state of being pressure-bonded to the substrate through a dry film resist, and bonded to the substrate.
Thereafter, development processing was performed with a developing solution to remove DFR having a diameter of 55 μm around the through-hole portion of the substrate.

Next, using a copper sulfate plating bath, electroplating was performed using a phosphorous copper plate as an anode and a stainless steel support as a cathode, and a region where the inside of the through hole and DFR were removed was formed with a copper plating film. At this time, a mushroom-type bump was formed on the upper portion of the conductor portion by further continuing the electroplating in the through hole even after the film formation was completed. When forming a copper plating film, a general-purpose copper sulfate plating bath containing 30 g / L of copper sulfate, 70 g / L of sulfuric acid, 500 mg / L of hydrochloric acid and an appropriate amount of additives was used, and the current density was 2 A / dm ² . went.

  Next, the substrate and the support were immersed in a resist stripping solution, the resin layer was dissolved, and the support was removed from the substrate by peeling the resin layer from the substrate.

  The wiring board thus obtained had mushroom bumps on the front surface and 15 μm high straight bumps on the back surface.

[Example 2]
A laser was used on a 3-inch ferrite (NiZn) substrate having a thickness of 250 μm, and a large number of through-holes having a diameter of 80 μm were formed in a matrix in the X and Y directions at a pitch of 200 μm.

  Next, after depositing a positive resist to a thickness of 5 μm on the substrate, a support made of titanium having a thickness of 0.05 mm and a diameter of 4 inches is separately prepared, and in a state of being pressure-bonded to the substrate through the resist. The substrate was treated at 110 ° C. and adhered to the substrate.

  Next, an exposure process was performed from the substrate side. In this exposure, a photomask is not used, and only a portion of the photoresist having a substrate through hole is exposed from the upper surface of the substrate. A hole having a diameter of 80 μm could be formed in the photoresist layer by developing after exposure.

  Next, electroplating was performed in the same manner as in Example 1 to form mushroom type bumps.

  Next, the substrate and the support were immersed in a resist stripping solution, the resin layer was dissolved, and the support was removed from the substrate by peeling the resin layer from the substrate.

  In removing the support from the substrate, the support was peeled off from the base while bending, and then DFR was removed with a resist stripping solution. For this reason, compared with Example 1, the peeling operation could be completed in a short time of 1/10.

  Further, the surface on which the mushroom bumps were formed was polished to form a convex portion having a height of 15 μm. Then, a mask pattern was formed by photolithography, an etching process was performed, and the bump was processed to have a copper diameter of 80 μm. Then, 1 μm of electroless Ni plating film and 0.1 μm of displacement gold plating film were formed on the bump tables on both sides. Furthermore, ball solder was placed on the double-sided bump table and reflowed to obtain a wiring board with double-sided and solder balls.

  The present invention is not limited to the above embodiments and examples, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is a thing.

  Further, in the above embodiment, stainless steel and titanium are used as the support material. However, the support material is not particularly limited, and any metal having a natural oxide film on the surface can be made of stainless steel. Instead, a difficult plating material such as aluminum or chromium can be used as the support. This is because the metal having a natural oxide film on the surface has a low adhesion strength with the electroplating film, so that it can be easily separated from the electroplating film, that is, the substrate after the treatment is completed. Furthermore, it is sufficient that the support has at least one surface of the substrate having conductivity, and not only when the entire support is made of a conductive material, a conductive layer is formed on a non-conductive substrate or the like. The substrate is also the conductive support of the present invention. For example, a wafer in which aluminum, titanium, chromium, or the like is formed on the surface of a silicon substrate by a sputtering method can be used as the conductive support of the present invention.

  The support is preferably flexible, and particularly preferably flexible so that it can be bent to a radius of curvature of 100 mm or less. This is because it is easy to peel the support from the substrate without dissolving the resist, and air bubbles are not easily involved when the support is attached to the substrate. In order to have flexibility, the support thickness is preferably about 5 to 100 μm. It is because handling is difficult if it is less than the range, and desired flexibility is lost if the range is exceeded.

  The method for manufacturing a wiring board according to the present invention can be widely used in the field of mounting electronic devices.

FIG. 1 is a view showing a cross section (end face) of an example of a manufacturing process of a wiring board according to the present invention. FIG. 2 is a view showing a cross section (end face) of an example of the manufacturing process of the wiring board of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board 10 ... Board | substrate 15 ... Through-hole 20 ... Photoresist layer 30 ... Photomask 40 ... Conductive support body

Claims (9)

A substrate having a through-hole, wherein the substrate is formed by depositing a metal by electroplating in a through-hole of a substrate having at least a surface thereof an insulator and an inner surface of the through-hole being an insulator. A manufacturing method of
The method
A substrate preparation step of preparing a substrate having a through-hole, wherein at least the substrate surface and the through-hole inner surface are insulators;
A conductive support preparation step of preparing a conductive support;
A photoresist layer forming step of forming a photoresist layer on one surface of the substrate or the conductive support;
An exposure process for performing an exposure process on the photoresist layer;
A substrate-conductive support bonding step of bonding the substrate and the conductive support through a photoresist layer;
Conducting a development process, removing the photoresist layer located below the through-hole opening of the substrate to expose a part of the conductive support, and a conductive support exposing step;
And a metal film forming step of forming a metal film in the through hole by electroplating using the conductive support as a cathode.   The method for manufacturing a wiring board according to claim 1, wherein the photoresist layer in the photoresist layer forming step is composed of a negative resist.   3. The method of manufacturing a wiring board according to claim 1, wherein, in the exposure processing step, the photoresist layer is exposed in a closed shape along the periphery of the through hole.   The method for manufacturing a wiring board according to claim 3, wherein, in the exposure processing step, the inner path portion of the closed path to be exposed is substantially the same size as the size of the through hole.   5. The method of manufacturing a wiring board according to claim 3, wherein closed-form exposure along the periphery of the through hole in the exposure processing step is performed through a photomask. The photoresist layer in the photoresist layer forming step is composed of a positive resist,
The exposure processing step is performed after the substrate-conductive support bonding step,
2. The method of manufacturing a wiring board according to claim 1, wherein the exposure process in the exposure process step is performed from above the substrate (through hole opening side) using the substrate as a mask.   The wiring substrate manufacturing method according to claim 6, wherein in the exposure processing step, the photoresist layer is exposed to a size substantially the same as the size of the through hole.   The method for manufacturing a wiring board according to claim 1, wherein the photoresist layer is made of a dry film resist.   9. The method for manufacturing a wiring board according to claim 1, wherein at least a surface of the conductive support is a metal plate mainly composed of any one of stainless steel, titanium, aluminum, chromium, and the metal. .

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