JP2007067030A - 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; a resin layer forming process of forming a resin layer on one side surface of a substrate to seal an opening of one end of a through hole; a conductive supporter preparing process; substrate-conductive supporter joining process of joining the substrate to a conductor supporter via the resin layer; a conductive supporter exposing process of removing the resin layer in a position where an opening of the one end of the through hole of the substrate is sealed to expose one part of the conductive supporter; and a metal film forming process of forming a metal film on the through hole by an electroplating method using the conductive supporter as a cathode. In this method, the metal film forming process has an operation for initially forming a tin film or an alloy film containing as tin a main component, and an operation for subsequently forming a film containing copper, gold and platinum or an alloy film containing them as a main component. <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 efficiently manufacturing a wiring board having a through conductor wiring having solder bumps.

  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. And by using this three-dimensional mounting technology to produce a semiconductor system, not only the degree of freedom of wiring design is expanded, but also the length of wiring can be shortened compared to the conventional planar system LSI, High frequency response is possible.

  In order to fabricate a substrate having such a through conductor wiring, a method is known in which through holes are formed and then attached to a conductor substrate by a through mask plating method as described below. That is, after preparing a substrate provided with a through hole and a copper foil, the copper foil is bonded to the substrate provided with the through hole with an adhesive using a vacuum laminator. Thereafter, the adhesive in the through hole portion is selectively removed by dry etching.

  Then, since only the bottom portion is in a conductive state, the plating can be deposited only from the bottom portion by performing electroplating using the copper foil as a cathode. By this method, voids and seams are hardly formed, and copper can be formed and filled at high speed with simple plating. Thereafter, polishing is performed from the back surface, and unnecessary portions including the copper foil are removed.

  However, in order to use what was manufactured by the said conventional method as a wiring board, you have to provide the bump for joining with an upper and lower electric element in the both ends of a through-hole further. That is, in the above conventional method, it is necessary to separately perform a complicated and accurate operation for forming a bump after forming and filling copper in the through hole.

Proceedings of the 13th Microelectronics Symposium, page 260, published by Japan Institute of Electronics Packaging, October 16, 2003

  The present invention was devised in such an actual state, and an object thereof is to provide a manufacturing 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, and resin for forming a resin layer on one surface of the substrate or the conductive support and sealing the opening at one end of the through hole There is a layer forming step, a substrate-conductor support bonding step for bonding the substrate and the conductor support through the resin layer, and a position where the opening at one end of the through hole of the substrate is sealed. Lead that exposes part of the conductive support by removing the resin layer A conductive support exposing step, and a metal film forming step of forming a metal in a through hole by electroplating using the conductive support as a cathode. In the metal film forming step, tin or tin is mainly used first. An operation for forming a film of an alloy as a component, and an operation for forming a film of copper, gold, platinum, or an alloy containing these as a main component are configured.

  Further, as a preferred embodiment of the present invention, in the metal film forming step, first, an operation of forming a tin or an alloy layer mainly containing tin, and then an operation of forming a nickel or an alloy mainly containing nickel, Then, an operation of forming a film of copper, gold, platinum or an alloy containing these as a main component is configured.

  As a preferred embodiment of the present invention, in the metal film forming step, first, an operation of forming a film of nickel or an alloy containing nickel as a main component, and then forming copper, gold, platinum, or an alloy containing these as a main component is formed. An operation to perform.

  Further, as a preferred embodiment of the present invention, the operation of forming a film of tin or an alloy containing tin as a main component in the metal film forming step is present at a position sealing the opening at one end of the through hole of the substrate. This is an operation for forming a bump as a connection terminal on the portion where the resin layer to be removed is removed.

  Further, as a preferred embodiment of the present invention, the operation of depositing nickel or an alloy containing nickel as a main component in the metal deposition step is present at a position sealing the opening at one end of the through hole of the substrate. This is an operation for forming a bump as a connection terminal on the portion where the resin layer to be removed is removed.

  Further, as a preferred embodiment of the present invention, an operation of forming a film of tin or an alloy containing tin as a main component after an operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step. , And so on.

  Further, as a preferred aspect of the present invention, after the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step, an operation of forming a film of nickel or a metal containing nickel as a main component Then, it is configured to have an operation of forming a film of tin or an alloy containing tin as a main component.

  Further, as a preferred embodiment of the present invention, after the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step, an operation of forming a film of nickel or a metal containing nickel as a main component , And so on.

  Further, as a preferred embodiment of the present invention, the operation of forming the film of tin or an alloy containing tin as a main component is configured as an operation of forming a bump as a connection terminal on the other end of the through hole of the substrate. Is done.

  Further, as a preferred aspect of the present invention, the operation of forming the nickel or nickel-based metal as a main component is configured as an operation of forming a bump as a connection terminal on the other end of the through hole of the substrate. Is done.

  Further, as a preferred embodiment of the present invention, the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step is performed after filling the through hole and further protruding to the other end. Thereafter, a process for flattening the substrate is performed so that the protruding metal portion is removed, and then tin or an alloy containing tin as a main component is formed on the flattened metal portion. It is configured to be operated.

  Further, as a preferred embodiment of the present invention, the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step is performed after filling the through hole and further protruding to the other end. Thereafter, a process for flattening the substrate is performed so that the protruding metal portion is removed, and then nickel or a metal containing nickel as a main component is formed on the flattened metal portion. An operation is performed, and then an operation of forming a film of tin or an alloy mainly composed of tin is performed.

  Further, as a preferred embodiment of the present invention, the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step is performed after filling the through hole and further protruding to the other end. Thereafter, a process for flattening the substrate is performed so that the protruding metal portion is removed, and then nickel or a metal containing nickel as a main component is formed on the flattened metal portion. It is configured to be operated.

  Moreover, as a preferable aspect of the present invention, the resin layer is configured to be a photoresist layer.

  According to the method for manufacturing a wiring board of the present invention, a bump for connection and an under barrier metal (UBM) layer are formed by a series of operations at the end of the through-hole conductor simultaneously with the formation of the conductor inside the through-hole. Can do. For this reason, a wiring board can be produced at a low cost by a simpler process.

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

  The present invention relates to a method of manufacturing a wiring board, in which a metal is deposited 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. This is a method for manufacturing a wiring board in which a connection bump and an under barrier metal (UBM) layer can be formed by a series of operations at the end of a through-hole conductor simultaneously with the formation of the conductor inside the hole.

  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 resin layer forming step for forming a resin layer on one surface of the substrate, and (4) a substrate for bonding the substrate and the conductor support through the resin layer. -Conductor support bonding step, and (5) Conductivity that removes the resin layer existing at the position sealing the opening at one end of the through hole of the substrate to expose a part of the conductive support. And (6) a metal film forming process for forming a metal film on the through hole by electroplating using the conductive support as a cathode.

FIG. 1 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. The insulator film can also be formed by an anodic oxidation method, coating, or the like.

  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 through the resin layer 20 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) Resin Layer Forming Step As shown in FIG. 1B, a photoresist layer 20 which is a preferred example of the resin layer 20 is formed on one surface (the lower plane in FIG. 1B) of the substrate 10. Then, the photoresist layer 20 seals the opening 15e at one end of the through hole.

  The photoresist suitably used in the present invention is not only a resin 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, etc. Means. Although a liquid resist can also be used, since it is necessary to form it so that the edge part of the through-hole 15 may be covered, it is preferable to use the film-form dry film resist (DFR) with a certain amount 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.

  When a negative photoresist layer 20 is used as the resin layer 20, as a preferred embodiment, an exposure process is performed on a predetermined portion of the photoresist layer 20 as shown in FIG. 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 example shown in FIG. 1 (B) is exposed in a closed loop shape along a large peripheral edge that extends slightly outward from the end 15e of the through hole 15 as shown. 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 the outer side of the 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 may be substantially the same as the hole diameter of the end portion 15 e of the through hole 15. Further, it can be made larger (example in FIG. 1B) 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, or slightly larger as illustrated.

  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 the exposed portion 22 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 resist. The dissolution reaction does not proceed any further. 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.

(4) Substrate-conductive support bonding step A conductive support bonding step of bonding the substrate 10 and the conductive support 40 via the photoresist layer 20 after the exposure processing step performed as the above-described preferred embodiment. Done.

  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, and is no longer dissolved in the developer in the subsequent development process. It shows that.

  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.

(5) Conductive Support Exposing Step Next, the photoresist layer (resin layer) present at the position where the opening at one end of the through hole of the substrate is sealed is removed to remove a part of the conductive support. A step of exposing the conductive support 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 face 22a after development is substantially vertical. For this reason, the patterning accuracy in the present invention is extremely high.

(6) 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. 1 (E), by performing electroplating using the conductive support 40 as a cathode, the inside of the through hole and the portion 2 ′ from which the resist has been removed (see FIG. 1 (D)). As a starting point, a metal which is a conductor is formed and filled.

  In the embodiment of the present invention shown in FIG. 1 (E), first, a low melting point alloy layer 51 mainly composed of tin or tin is formed, and then nickel or an alloy mainly composed of nickel is diffused. A protective layer (UBM) 52 is formed. These two layers are preferably formed in a portion where the resist is removed. Subsequently, copper, gold, platinum, or an alloy containing these as main components is formed as a conductive layer 50 at a location corresponding to the substrate through hole. The conductive layer 50 is particularly preferably copper because it is a low-resistance conductor, a high-melting-point metal, and is inexpensive and easy to form.

  As an alloy mainly composed of tin which is a constituent material of the low melting point alloy layer 51, various known composition films such as SnPb, SnAg and SnCu can be used as a low melting point solder plating film. Particularly preferred is Sn or SnAg. By forming the film first, it is formed in the resin layer removal portion, that is, the DFR removal portion, is in a convex state from the back surface of the wiring board, and becomes a lower surface bump of the wiring board.

  The diffusion prevention layer 52 functions, for example, to prevent the components of the low-melting-point alloy layer 51 containing tin as a main component from diffusing into the metal of the conductive layer 50 filling the through holes, for example, copper. . The film thickness of the diffusion preventing layer 52 is 0.2 to 20 μm, preferably about 1 to 10 μm. The diffusion prevention layer 52 can be omitted depending on the design specifications. On the contrary, the low melting point alloy layer 51 can be entirely replaced with the diffusion prevention layer 52.

  Further, as shown in FIG. 1E, after the substrate through hole portion is filled and formed as a conductive layer 50, a diffusion prevention layer 56 made of nickel or an alloy containing nickel as a main component is further formed, and further, tin Alternatively, it is preferable to have a step of forming a low melting point alloy layer 57 made of an alloy containing tin as a main component. These become upper surface bumps of the wiring board. The diffusion preventing layer 56 can be omitted depending on the design specifications. On the contrary, the low melting point alloy layer 57 can be entirely replaced with the diffusion preventing layer 56.

  The diffusion preventing layer 56 and the low-melting point alloy layer 57, particularly the low-melting point alloy layer 57, are hemispherical from the substrate surface because the side surfaces are not limited. Therefore, if necessary, an insulator such as polyimide may be formed in a portion other than the through hole on the substrate surface. In this case, it grows hemispherically from above the polyimide layer.

  It should be noted that after the resin layer removal portion and the through-hole portion are filled and formed, etc. are not strictly determined. The first low-melting-point alloy layer 51 containing tin as a main component is thinner than the resin layer from which the thin-film alloy layer 51 is removed, and is composed of, for example, copper, gold, platinum, or an alloy containing these as main components. The conductive layer 50 may be formed on the resin layer removal portion, or the low melting point alloy layer 51 mainly composed of tin may be thick and may be formed on the through hole portion. In particular, in the former case, it is possible to positively project copper, gold, platinum, or an alloy containing these as main components as bump bases by about 1 to 50 μm from the wiring board surface. Similarly, when bumps are formed on the surface, the position of the interface between the different types of plating films may be increased or decreased by about 50 μm with respect to the substrate surface.

Further, when there is a variation in the film formation speed in the through-holes 15 and only a part of the through-holes 15 is excessively formed and protrudes greatly from the substrate surface, the plating is interrupted once, After the surface is polished, the diffusion preventing layer 56 (barrier layer) or the low melting point alloy layer 57 (solder bump layer) may be electroplated on the substrate surface. That is, the operation of forming a film of copper, gold, platinum, or an alloy containing these as a main component in the metal film forming process is performed after filling the through hole 15 and further protruding to the other end, and then the protruding metal A process for flattening the substrate is performed so that the portion is removed, and then,
(I) An operation of depositing tin or an alloy containing tin as a main component (deposition of the low melting point alloy layer 57) on the planarized metal portion, or
(II) An operation of depositing nickel or a metal containing nickel as a main component (deposition of the diffusion prevention layer 56) on the flattened metal portion, and then forming tin or an alloy containing tin as a main component. Performing a film forming operation (deposition of the low melting point alloy layer 57), or
(III) An operation (film formation of the diffusion prevention layer 56) for forming nickel or a metal containing nickel as a main component on the planarized metal portion is performed. In this case, the diffusion prevention layer 56 also functions as a connection terminal.

  After such a film forming process, the photoresist layer 20 is peeled from the substrate 10 using a stripping solution or the like. As a result, the conductive support 40 is removed from the substrate 10 as shown in FIG. Next, as shown in FIG. 1G, the low melting point alloy layers 51 and 57 (solder parts) are processed into a hemispherical shape by so-called reflow treatment.

  The wiring board 1 of the present invention formed through such a process includes bumps made of an alloy mainly composed of tin, for example, which is convex from the surface of the wiring board on one side (back side) or both sides of the through conductor. Yes. For this reason, joining becomes possible by reflowing with another element in a pressure-bonded state as it is.

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

  However, in addition to this mode, the following procedure may be used to change the joining order. That is, first, the resin layer 20 is first formed on the surface of one side of the conductive support 40, a predetermined exposure process is performed on the resin layer 20, and then the substrate 10 and the conductive material are interposed via the resin layer 20. You may make it join the support body 40. FIG. 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, similarly to the embodiment described above, a resin layer forming step for forming a resin layer on one surface of the substrate and sealing the opening at one end of the through hole, and a conductive support are prepared. A conductive support preparing step, a substrate-conductor support bonding step for bonding the substrate and the conductor support through the resin layer, and an opening at one end of the through hole of the substrate is sealed. A conductive support exposing step of removing a resin layer present at a position to expose a part of the conductive support, and a metal film forming a metal in a through hole by electroplating using the conductive support as a cathode And a layer formed on the removed portion of the resin layer is used as a bump.

  However, the embodiment shown in FIG. 2 is different in that a positive resist is used as the resin layer and that a substrate having a through-hole itself functions as a photomask without using a separately prepared photomask.

  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 via a resin 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) Resin Layer Forming Step Next, as shown in FIG. 2B, a photoresist layer 20 is formed as a resin layer 20 on one surface of the substrate 10 (the lower flat surface in FIG. 2B). It is formed.

  The photoresist in the present invention is defined as described above. A liquid resist can also be used, but since it is necessary to form it so as to cover the end portion 15e 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) Conductive Support Exposure 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 10 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.

  Next, a developing process is performed, and a conductive support exposing step is performed in which the photoresist layer located below the through hole opening of the substrate is removed to expose a part of the conductive support.

  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.

(2-6) Metal Film Formation Step Next, a metal film formation step is performed in which metal is formed in the through hole by electroplating using the bonded conductive support 40 as a cathode. The details of this metal film forming step and the subsequent operations up to FIG. 2 (F) are the same as those described in the embodiment of FIG. 1, and a detailed description thereof will be omitted here.

<Modification of Second Embodiment>
As described above, in the second embodiment based on the flow of FIG. 2, first, the resin layer 20 is formed on one surface of the substrate 10, and the substrate 10 and the conductive support 40 are connected via the resin layer 20. After bonding, the resin layer 20 is subjected to predetermined exposure processing. However, in addition to this mode, the following procedure may be used to change the joining order. That is, first, the resin layer 20 is formed on the surface of one side of the conductive support 40, the substrate 10 and the conductive support 40 are bonded through the resin layer 20, and then the resin layer 20 may be subjected to a predetermined exposure process. 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]
An etching mask was formed on a silicon substrate having a thickness of 150 μm and a diameter of 4 inches. This etching mask was a pattern in which many 50 μm square patterns were arranged in a matrix in the X and Y directions at a pitch of 170 μm.

Next, etching was performed by a deep RIE method to form a 50 μm square through hole.
A treatment was performed at 1100 ° C. for 5 hours in a diffusion furnace, and a 0.5 μm thick silicon oxide insulating layer was formed on the substrate surface and the inner surface of the through hole. This is because the used silicon substrate has conductivity by doping.

  Next, a negative DFR with a thickness of 50 μm is pressure-bonded to a silicon substrate at 110 ° C., and a portion surrounded by a double-angle pattern with an outer shape of 70 μm square and an inner shape of 60 μm square is exposed and developed around the through hole. The DFR in the through hole portion was removed.

  Next, a stainless steel support member having a thickness of 0.1 mm and a diameter of 4 inches was prepared separately, treated at 120 ° C. in a state of being bonded to the substrate, and bonded to the substrate.

  First, a film of 45 μm is formed using a SnPb (Pb: 37%) plating bath, and then a film of 10 μm is formed using a sulfamic acid Ni plating bath. The film was again formed into a 10 μm film using a Ni sulfamate plating bath, and a 50 μm film was formed using a SnPb (Pb: 37%) plating bath. In both cases, electroplating was performed using a stainless steel support as a cathode.

  The substrate and the support were immersed in a resist stripping solution, the DFR layer was dissolved, and the support was removed from the substrate. Then, the reflow process was performed. In this way, a wiring substrate having SnPb bumps with Ni under barrier metal layers on both surfaces was obtained.

[Example 2]
A laser was used on a 3-inch diameter ferrite substrate having a plate thickness of 350 μm, and a large number of through-holes (substantially circular) having a diameter of 80 μm were formed in a matrix in the X and Y directions at a pitch of 200 μm.
Next, a negative DFR with a thickness of 50 μm is pressure bonded to a silicon substrate at 110 ° C., and a portion surrounded by a donut pattern having an outer diameter of 100 μm square and an inner diameter of 80 μm square is exposed and developed around the through hole. Partial DFR was removed.

  Next, a stainless steel support member having a thickness of 0.1 mm and a diameter of 4 inches was prepared separately, treated at 120 ° C. in a state of being bonded to the substrate, and bonded to the substrate.

  First, a film of 45 μm is formed using a SnPb (Pb: 37%) plating bath, and then a film of 10 μm is formed using a nickel sulfamate plating bath. The film was formed. Then, since the plating speed was different depending on the through hole, there was not only a through hole in which film formation was completed up to the substrate surface but also a through hole in which mushroom bumps of 50 μm or more were formed on the substrate surface. Therefore, the surface was flattened by polishing 10 μm from the substrate surface.

  Thereafter, a 1 μm UBM film was formed and patterned by a plating method, and solder balls were mounted. Further, reflow processing was performed to spheroidize the solder on both sides to obtain a wiring board having both sides 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.

  In the above embodiment, the cross-sectional shape of the through-hole is circular, but is not particularly limited, and the hole may be formed to have an arbitrary cross-sectional shape such as a circle, an ellipse, or a polygon. it can. In order to accurately remove the resin layer below the through hole, the resin layer is preferably made of a photoresist and patterned by an exposure process.

  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 ... Resin layer 30 ... Photomask 40 ... Conductive support body 50 ... Conductive layer 51, 57 ... Low melting-point alloy layer 52, 56 ... Diffusion prevention layer

Claims (14)

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 resin layer forming step of forming a resin layer on one surface of the substrate or the conductive support and sealing the opening at one end of the through hole; and
A substrate-conductor support bonding step for bonding the substrate and the conductor support through the resin layer;
A conductive support exposing step of removing a portion of the conductive support by removing the resin layer present at a position sealing the opening at one end of the through hole of the substrate;
A metal film forming step of forming a metal film in the through hole by electroplating using the conductive support as a cathode,
In the metal film forming step, first, an operation of forming a film of tin or an alloy containing tin as a main component, followed by an operation of forming a film of copper, gold, platinum, or an alloy containing these as a main component is provided. A method of manufacturing a wiring board, characterized in that   In the metal film forming step, first, an operation of forming a tin or an alloy layer mainly composed of tin, an operation of forming a film of nickel or an alloy mainly composed of nickel, and then copper, gold, platinum, or these The method for manufacturing a wiring board according to claim 1, further comprising an operation of forming a film of an alloy having a main component.   In the metal film forming step, first, an operation of forming a film of nickel or an alloy containing nickel as a main component, followed by an operation of forming a film of copper, gold, platinum or an alloy containing these as a main component is provided. Item 4. A method for manufacturing a wiring board according to Item 1.   The operation of depositing tin or a tin-based alloy in the metal film forming step is connected to a portion where the resin layer existing at the position where the opening at one end of the through hole of the substrate is sealed is removed. The method for manufacturing a wiring board according to claim 1, wherein the operation is an operation of forming a bump as a terminal.   The operation of depositing nickel or a nickel-based alloy in the metal film-forming step is connected to a portion where the resin layer existing at the position where the opening at one end of the through hole of the substrate is sealed is removed. The method for manufacturing a wiring board according to claim 3, wherein the operation is an operation of forming a bump as a terminal.   2. An operation of forming a film of tin or an alloy containing tin as a main component after the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step. The manufacturing method of the wiring board in any one of Claim 3 thru | or.   After the operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step, an operation of forming a film of nickel or a metal containing nickel as a main component, and then tin or tin as a main component The method for manufacturing a wiring board according to any one of claims 1 to 3, further comprising: an operation of forming an alloy as a film.   2. An operation of depositing nickel or a nickel-based metal after the operation of depositing copper, gold, platinum or an alloy containing these as a main component in the metal film-forming step. The manufacturing method of the wiring board in any one of Claim 3 thru | or.   The operation for forming a film of the tin or an alloy containing tin as a main component is an operation for forming a bump as a connection terminal on the other end of the through hole of the substrate. Wiring board manufacturing method.   The wiring board according to claim 8, wherein the operation of forming the nickel or nickel-based metal film is an operation of forming a bump as a connection terminal on the other end of the through hole of the board. Production method. The operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step is performed until the through hole is filled and further projected to the other end,
Thereafter, a process of flattening the substrate is performed so that the protruding metal portion is removed,
4. The method for manufacturing a wiring board according to claim 1, wherein after that, an operation of forming a film of tin or an alloy containing tin as a main component is performed on the flattened metal portion. . The operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step is performed until the through hole is filled and further projected to the other end,
Thereafter, a process of flattening the substrate is performed so that the protruding metal portion is removed,
Thereafter, an operation of forming a film of nickel or a metal containing nickel as a main component on a flattened metal portion, followed by an operation of forming a film of tin or an alloy containing tin as a main component is performed. The manufacturing method of the wiring board in any one of Claims 1 thru | or 3. The operation of forming a film of copper, gold, platinum or an alloy containing these as a main component in the metal film forming step is performed until the through hole is filled and further projected to the other end,
Thereafter, a process of flattening the substrate is performed so that the protruding metal portion is removed,
4. The method for manufacturing a wiring board according to claim 1, wherein after that, an operation of forming a film of nickel or a metal containing nickel as a main component on the planarized metal portion is performed. .   The method for manufacturing a wiring board according to claim 1, wherein the resin layer is a photoresist layer.

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