JP2010021327A - Method for manufacturing wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a wiring board which easily fills a through-hole with a plating metal by electrolytic metal plating using an electrolytic plating liquid requiring great attention in management. <P>SOLUTION: A metal thin film 14 is formed over the entire board surface including the inner wall surface of a through-hole 12 of a board 10. One surface of the board 10 is covered with a first insulating film 16, while the other surface of the board 10 is plated with a first electrolytic metal using the metal thin film 14 as a feeding layer. An opening of the through-hole 12 closer to the other surface is closed with a plating metal 18, and the first insulating film 16 is separated to open the through-hole 12 on the side of one surface of the board 10. The plating metal 18 is covered with a second insulating film 20, and the metal thin film 14 exposed in a space 12a remaining in the open through-hole 12 is eliminated. Then, the space 12a is filled by post-plating with a second electrolytic metal using the plating metal layer 18 as a feeding layer to form a through-electrode for electrically connecting both surfaces of the board 10 in the direction of its thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a wiring board, and more particularly to a method of manufacturing a wiring board that can fill a through hole penetrating the board with a plated metal by electrolytic metal plating without voids.

As a filling method for filling a plated metal with electrolytic metal plating in a through hole penetrating the substrate in order to form a via in the substrate, for example, the following patent document 1 proposes a through hole filling method shown in FIG. .
In the through hole filling method shown in FIG. 9, first, as shown in FIG. 9 (a), a cylindrical through hole 102 is formed on a resin substrate 100 made of a resin as an insulating material by a drill, and then, as shown in FIG. As shown in b), a metal thin film 104 is formed on the surface of the resin substrate 100 including the inner wall surface of the through hole 102 by electroless plating.
Further, the plating resist 106 applied so as to cover the metal thin film 104 including the through hole 102 is patterned to expose the portion of the metal thin film 104 where the through hole 102 and the wiring pattern are to be formed (FIG. 9B).

  Next, electrolytic metal plating using the metal thin film 104 as a power feeding layer is performed, and a plated metal layer 108 is formed on the inner wall surface of the through hole 102 and the exposed surface of the metal thin film 104. In this electrolytic metal plating, when electrolytic metal plating is performed on the resin substrate 100 while stirring, the metal deposition rate on the straight inner wall surface in the through hole 102 is higher than the metal deposition rate on the substrate surface of the resin substrate 100. Use fast electrolytic plating solution. When the resin substrate 100 is immersed in the electrolytic plating solution, and the electrolytic metal plating is applied to the resin substrate 100 while stirring the electrolytic plating solution, as shown in FIG. 9C, the vicinity of the opening of the through hole 102 is obtained. A metal layer 110 thicker than the metal layer can be formed in the middle of the through hole 102, and the narrowest portion 102 a is formed in the vicinity of the middle of the through hole 102.

Further, electrolytic metal plating is continued on the resin substrate 100 including the through hole 102 in which the metal layer 110 thicker than the metal layer 108 in the vicinity of the opening is formed in the vicinity of the middle portion. As a result, current concentrates on the thick metal layer 110 formed in the vicinity of the middle portion of the through hole 102, and the metal layer 110 in the vicinity of the middle portion becomes thicker. Finally, the narrowest portion 102a is closed to form recesses 112 and 112 that are opened on both surfaces of the resin substrate 100 (FIG. 9D).
By continuing electrolytic plating subsequently, it is possible to fill the recesses 112 and 112 formed in the resin substrate 100 with metal and form a filling layer 114 free from defects such as voids.
JP 2005-93934 A

According to the through hole filling method using electrolytic metal plating proposed in Patent Document 1, it is possible to fill with metal plating without forming voids in the through holes.
By the way, in the filling method of the through hole of patent document 1, it is required to use the electrolytic plating solution whose metal deposition rate with respect to the straight inner wall surface in a through hole is faster than the metal deposition rate of the substrate surface of a resin substrate.
However, since the electrolytic plating solution has a large change with time, strict management is required that the electrolytic plating solution to be used has a predetermined performance.
Therefore, the present inventor has solved the problem of the conventional through hole filling method in which the inside of the through hole is filled with the plating metal by electrolytic metal plating using an electrolytic plating solution that pays great attention to management, and performs strict management. It is an object of the present invention to provide a method of manufacturing a wiring board that can easily fill a through hole with a plated metal by electrolytic metal plating even when an unnecessary electrolytic plating solution is used.

As a result of studying to solve the above-mentioned problems, the present inventor, when filling the plated hole with electrolytic metal plating in the through hole penetrating the substrate, one surface of the substrate surface in which one of the openings of the through hole is opened Apply electrolytic metal plating to one side of the through hole, fill the plated metal with one side of the through hole, and then apply electrolytic metal plating to the other side of the substrate surface where the other opening of the through hole opens. When filling the space remaining on the other side with the plating metal, the plating seed layer is removed in advance so as to be post-plated, and it is found that the plating metal can be filled without forming a void in the through hole, The present invention has been reached.
That is, according to the present invention, a first metal thin film is formed on the entire surface of a substrate including an inner wall surface of a through hole having openings on one side and the other side of the substrate formed of an insulating material. Is coated with a first insulating film, and the other surface side opening of the through hole is closed with a plating metal by applying first electrolytic metal plating using the first metal thin film as a power feeding layer on the other surface side of the substrate. And removing the first insulating film to open the opening on the one surface side of the through hole, and covering the surface of the first plated metal layer formed on the other surface side of the substrate with the second insulating film. The space remaining in the through-hole after removing the first metal thin film exposed at least on the inner wall surface of the through-hole is filled with the second electrolytic metal plating using the first plating metal layer as a power feeding layer. One of the substrates A method of manufacturing a wiring board and forming a through electrode for electrically connecting the side and the other surface side.

  In addition, a step of forming a plating resist having an opening pattern identical to a wiring pattern to be formed on the other surface side of the substrate prior to performing the first electrolytic metal plating using the first metal thin film as a power feeding layer. It is characterized by having. Thereby, a wiring pattern can be easily formed in a detailed pattern by 1st electrolytic metal plating.

  And forming a second metal thin film on the one surface side of the substrate after forming the second plated metal layer to the position of the end surface of the through hole on the one surface side; The method further includes the step of performing three electrolytic metal plating and laminating a third plating metal layer on the second metal thin film. This makes it possible to form a metal layer that will be a wiring pattern on both sides of the substrate.

  Prior to performing third electrolytic metal plating using the second metal thin film as a power feeding layer, the second metal thin film has the same opening pattern as a wiring pattern to be formed on the second metal thin film. The method further includes a step of forming a plating resist. Thereby, a detailed wiring pattern can be easily formed on both surfaces of the substrate.

  The method further includes a step of forming a wiring pattern by etching at least one of the first plating metal layer and the third plating metal layer into a required pattern. This also makes it possible to easily form a wiring pattern on the substrate.

  Further, in the second electrolytic metal plating, the deposition rate of the plating metal is made slower than in the first electrolytic metal plating, or at least in the second electrolytic metal plating, by using an electroplating solution for via fill. The plated metal can be reliably filled without forming a void in the through hole.

In general, when electrolytic metal plating is applied to a through hole of a substrate, current concentrates on the opening edge of the through hole and the angular portion in the vicinity thereof, and the plating metal tends to be deposited on the opening edge and the vicinity thereof. For this reason, the plated metal layer starts to grow from the opening edge of the through hole and the vicinity thereof, and finally tends to block both openings of the through hole with the void remaining in the through hole. In this regard, in the method for filling a through hole and the method for manufacturing a wiring board according to the present invention, when filling the through hole formed in the substrate by electrolytic metal plating with the plated metal, The first electrolytic metal plating power supply layer portion that appears on the other opening side of the through hole is removed after the opening portion of the through hole is closed while filling with the plating metal of the first electrolytic metal plating. By filling the through hole with the second electrolytic metal plating using only one electrolytic metal plating as a power feeding layer, the other opening of the through hole is closed.
As described above, in the present invention, the through hole formed in the substrate is formed into a concave shape and filled with the plating metal by the first electrolytic metal plating, and then the power supply layer of the first electrolytic metal plating is removed and then the first electrolytic metal is removed. By performing the second electrolytic metal plating from the end surface opposite to the plating filling side, the second electrolytic metal plating can be post-plated with respect to the first electrolytic metal plating. As a result, the plated metal can be reliably filled without leaving voids in the through holes, and the reliability of electrical connection in the through holes can be improved.
Further, in the through hole filling method according to the present invention, it is not necessary to form a plating metal layer thicker than the plating metal layer near the opening of the through hole near the middle of the through hole. An electrolytic plating solution for filling can be used, and strict management of the electrolytic plating solution can be eliminated.

(First embodiment)
One example of an embodiment of a manufacturing method of a wiring board to which a through hole filling method according to the present invention is applied will be described with reference to cross-sectional views in each step in FIGS.
First, as shown in FIG. 1A, a through hole 12 is formed in a substrate 10 by drilling, laser beam irradiation, or the like. The substrate 10 is formed of an insulating material such as epoxy resin or ceramic.
Next, as shown in FIG. 1B, a first metal thin film 14 is formed on the entire surface of the substrate 10 including the inner wall surface of the through hole 12 on the substrate 10 on which the through hole 12 is formed. The first metal thin film 14 can be formed by electroless plating, and the thickness of the first metal thin film 14 is about 1 μm. The first metal thin film 14 is preferably a copper thin film formed by electroless copper plating.
Further, as shown in FIG. 1C, one surface side of the substrate 10 is covered with the first insulating film 16, and one of the openings of the through hole 12 is closed. Through the first insulating film 16, the through hole 12 can be formed into a concave shape. As the first insulating film 16, a dry film resist can be suitably used.

The substrate 10 in the state shown in FIG. 1C whose one side is covered with the first insulating film 16 is immersed in an electrolytic plating solution stored in a plating tank with stirring, and the metal thin film 14 is used as a power feeding layer. 1 Apply electrolytic metal plating. Since one surface (the lower surface in FIG. 1 (c)) of one of the through holes 12 formed in the substrate 10 is closed by the first insulating film 16, the first electrolytic metal plating is performed. Is deposited on the other side of the substrate 10 (upper surface in FIG. 1C).
In the first electrolytic metal plating, it is preferable to use an electrolytic plating solution for via fill as the electrolytic plating solution. In particular, electrolytic copper plating is employed as the first electrolytic metal plating, and copper sulfate, sulfuric acid, and chloride ions, which are proposed in, for example, JP-A-2006-57177, are basically used as electrolytic copper plating solutions for via fill. An electrolytic copper plating solution having a composition and a polymer compound as a surfactant, a sulfur compound as a brightener, and a nitrogen-containing compound as a leveler can be suitably used. In this electrolytic copper plating solution, the plating metal can be smoothly embedded in the recessed via hole by the leveler effect by stirring.

  As shown in FIG.1 (d), the 1st metal plating layer 18 is formed in the other surface side of the board | substrate 10 by 1st electrolytic metal plating. The first plated metal layer 18 is also formed on the inner wall surface in the vicinity of the other opening of the through hole 12, but the protruding portion 18a protrudes from the periphery of the opening toward the center of the opening. This is because the current tends to concentrate on the corner portion forming the periphery of the other opening of the through hole 12. Since this protrusion 18a grows with the passage of time of the first electrolytic metal plating, the other opening of the through hole 12 is blocked by the first plating metal layer 18 as shown in FIG. become. A space 12a is formed on one opening side of the through hole 12 with the other opening closed. Since the other opening of the through-hole 12 is closed, the space 12a is not filled with the first electrolytic metal plating because the electrolytic plating solution is not replaced or contacted.

After the first plated metal layer 18 is deposited on the surface of the substrate where the other opening of the through hole 12 opens, the first insulating film 16 is peeled off as shown in FIG. 2B. Then, one of the openings of the through hole 12 is opened. In the vicinity of one opening of the through hole 12, the other opening is closed by the first plated metal layer 18 and is formed in a concave shape.
The substrate 10 from which the first insulating film 16 has been peeled is covered with the second insulating film 20 on the surface of the first plated metal layer 18 formed on the other surface side of the substrate 10 as shown in FIG. . As the second insulating film 20, a dry film resist can be suitably used.
Next, as shown in FIG. 3A, the first metal thin film 14 serving as a power feeding layer of the first plated metal layer 18 appearing (exposed) in the space 12 a on one opening side of the through hole 12. Is removed by flash etching.

  By performing the flash etching of the first metal thin film 14 as described above, when electrolytic plating is performed from one opening side of the through hole 12 into the through hole 12, the current flowing to one opening edge of the through hole 12 Concentration can be avoided. Thereby, it can block | close in the state which was gradually filled with the plating metal from the back | inner side in the space part 12a of the one opening side of the through hole 12. FIG. That is, since voids are not formed in the space 12a and the plated metal is filled, an improvement in the reliability of electrical connection in the through hole 12 can be expected.

  The substrate 10 shown in FIG. 3A is immersed in an electrolytic plating solution stored in a plating tank, and second electrolytic metal plating is performed using the first plated metal layer 18 as a power feeding layer. Such second electrolytic metal plating is post plating on the first plating metal layer 18 as shown in FIG. 3B, and the inside of the through hole 12 can be filled without voids. As the electrolytic plating solution in the second electrolytic metal plating, it is preferable to use a widely used electrolytic copper plating solution for via fill. As the electrolytic copper plating solution for via fill, one having the same configuration as the electrolytic copper plating for via fill used in the first electrolytic metal plating can be used.

In the second electrolytic metal plating, it is preferable to employ electrolytic metal plating conditions in which the deposition rate of the plated metal is slower than that of the first electrolytic metal plating. This is because by applying such electrolytic metal plating conditions, it is possible to reliably fill the plated metal without forming voids in the space 12a formed on the one opening side of the through hole 12. The adjustment of the deposition rate of the plating metal can be performed by adjusting the current density and the like.
In the substrate 10 subjected to the second electrolytic metal plating, as shown in FIG. 3 (b), the second plating metal layer 22 is formed on one surface side of the substrate 10, and the space portion 12a shown in FIG. 3 (a) is filled. The through hole 12 can be densely filled with the first plating metal layer 18 and the second plating metal layer 22, and a through electrode for electrically connecting the one surface side and the other surface side of the substrate 10 is formed. can do. The second electrolytic metal plating is continued until the deposition height position of the second plating metal layer 22 is flush with the opening surface on one side of the through hole 12.

Next, as shown in FIG. 3C, the second metal thin film 24 is laminated on the surface of the second plated metal layer 22 and one surface of the substrate 10 (the lower surface of the substrate 10 shown in FIG. 3). . The second metal thin film 24 can be formed by electroless plating, sputtering, or the like, and has a thickness of about 1 μm. Such a second metal thin film 24 is preferably a copper thin film formed by electroless copper plating. A substrate 10 having a second metal thin film 24 formed on one surface and a second insulating film 20 formed on the other surface is immersed in an electrolytic plating solution stored in a plating tank with stirring, and the second metal thin film is immersed therein. Third electrolytic metal plating is performed using 24 as a power feeding layer. In the present embodiment, electrolytic copper plating was performed as the third electrolytic metal plating. As shown in FIG. 4A, a third plated metal layer 26 is formed on the second metal thin film 24 by the third electrolytic metal plating. And if the 2nd insulating film 20 is removed, the wiring board 30 as shown in FIG.4 (b) can be obtained.
Thereafter, if necessary, the first plating metal layer 18 and the third plating metal layer 26 covering the one surface and the other surface of the wiring board 30 are etched by a known method such as a subtractive method. Thus, a wiring pattern formed of a plated metal layer can be formed on each of the upper and lower surfaces of the substrate 10.

By the way, when the inside of the through hole 12 is filled with the plating metal by the second electrolytic metal plating, due to the variation in the amount of deposition of the plating metal, the front end surface of the post plating portion (the lower end surface of the substrate 10 shown in FIG. 4). The height is not uniform, and a recess 22a may be formed in a part of the through hole 12 as shown in FIG.
Since the electroless copper plating that is the second metal thin film 24 adheres following the surface shape of the surface to be deposited, the concave portion 24a may also be formed in the second metal thin film 24 in such a concave portion. is there. In such a case, if a via fill plating solution is used as the third electrolytic metal plating solution, the third plating metal layer 26 is deposited in preference to the recess 24a portion of the second metal thin film 24, as shown in FIG. It is convenient because the third plated metal layer 26 formed on the flat surface can be finished.

(Second Embodiment)
In the first embodiment, the first plated metal layer 18 and the third plated metal layer 26 are formed by electrolytic metal plating on each surface where the opening of the through hole 12 of the substrate 10 in which the through hole 12 is formed opens. In the present embodiment, the respective plated metal layers are formed in the wiring pattern by the subtractive method. However, in the present embodiment, each of the first plated metal layer 18 and the third plated metal layer 26 is formed by the semi-additive method. Embodiments will be described.
In the manufacturing process of the wiring board according to the present embodiment, since the steps from FIGS. 1A to 1C described in the first embodiment are common steps, the reference numerals used in the description of the first embodiment are used. The detailed description is omitted by giving.

5-8 is sectional drawing which shows the state in each process after FIG.1 (c).
As shown in FIG. 5A, prior to the first electrolytic metal plating on the surface of the substrate (the upper surface of the substrate 10 shown in FIG. 5) where the other opening side of the through hole 12 opens, the first electrolysis is performed. On the surface of the first metal thin film 14 on which the metal plating is to be deposited, a first plating resist 40 having an opening at a portion to be a wiring of a wiring pattern to be formed on the upper surface side of the substrate 10 shown in FIG. . The first plating resist 40 can be formed by using a photosensitive resin film and exposing and developing along the wiring pattern.
After the first plating resist 40 is formed in a required opening pattern, it is immersed in an electrolytic plating solution stored in a plating tank with stirring, and first electrolytic metal plating using the metal thin film 14 as a power feeding layer is performed. In the first electrolytic metal plating, it is preferable to use an electrolytic plating solution for via fill as the electrolytic plating solution, as in the first embodiment.

  By performing the first electrolytic metal plating, the first plating metal layer 18 is deposited in the opening portion of the first plating resist 40 formed on the other surface side of the substrate 10 as shown in FIG. The first plated metal layer 18 is also formed on the inner wall surface in the vicinity of the other opening of the through hole 12, but protrudes from the inner periphery of the opening of the first plating resist 40 toward the center of the opening of the through hole 12. 18a protrudes. This is because the current tends to concentrate on the corner portion forming the periphery of the other opening of the through hole 12. Since this protrusion 18a grows with the lapse of time of the first electrolytic metal plating, the other opening of the through hole 12 is blocked by the first plating metal layer 18 as shown in FIG. 5C. become. A space 12a is formed on one opening side of the through hole 12 with the other opening closed. Since the other opening of the through-hole 12 is closed, the space 12a is not filled with the first electrolytic metal plating because the electrolytic plating solution is not replaced or contacted.

A first plated metal layer 18 is deposited on the surface of the substrate where the other opening of the through hole 12 is open so as to be a substantially flat surface. Thereafter, the first insulating film 16 is removed to open one of the openings of the through hole 12, and the surface opposite to the surface from which the first insulating film 16 is removed (the surface of the first plated metal layer 18). The entire surface is covered with the second insulating film 20. A dry film resist is preferably used as the second insulating film 20. FIG. 6A shows a state where the first insulating film 16 is removed and the second insulating film 20 is formed. As is clear from FIG. 6A, in the vicinity of one opening of the through hole 12, the other opening is closed by the first plating metal layer 18 and formed in a concave shape.
Next, as shown in FIG. 6B, the first metal thin film 14 serving as the power feeding layer of the first plated metal layer 18 that appears (exposed) in the space 12 a on the one opening side of the through hole 12. Is removed by flash etching.

  The substrate 10 shown in FIG. 6B is immersed in an electrolytic plating solution stored in a plating tank, and second electrolytic metal plating is performed using the first plated metal layer 18 as a power feeding layer. The second electrolytic metal plating is post plating on the first plating metal layer 18 as shown in FIG. 6C, and the inside of the through hole 12 can be filled without voids. As the electrolytic plating solution in the second electrolytic metal plating, it is preferable to use a widely used electrolytic copper plating solution for via fill. As the electrolytic copper plating solution for via fill, one having the same configuration as the electrolytic copper plating for via fill used in the first electrolytic metal plating is suitably used.

In addition, in the second electrolytic metal plating, it is preferable to adopt the electrolytic metal plating conditions in which the deposition rate of the plated metal is slower than in the first electrolytic metal plating, as in the first embodiment. This is because by applying such electrolytic metal plating conditions, it is possible to reliably fill the plated metal without forming voids in the space 12a formed on the one opening side of the through hole 12. The adjustment of the deposition rate of the plating metal can be performed by adjusting the current density and the like.
In the substrate 10 subjected to the second electrolytic metal plating, as shown in FIG. 6C, the second plating metal layer 22 is formed on one surface side of the substrate 10, and the space portion 12a shown in FIG. 6B is filled. Is done. The through hole 12 is densely filled with the first plated metal layer 18 and the second plated metal layer 22, and a through electrode that enables electrical connection in the plate thickness direction of the substrate 10 is formed. The second electrolytic metal plating is continued until the deposition height position of the second plating metal layer 22 is flush with the opening surface on one side of the through hole 12.

Next, as shown in FIG. 7A, the second metal thin film 24 is laminated on the surface of the second plated metal layer 22 and one surface of the substrate 10 (the lower surface of the substrate 10 shown in FIG. 7). . The second metal thin film 24 can be formed by electroless plating, sputtering, or the like, and has a thickness of about 1 μm. Such a second metal thin film 24 is preferably a copper thin film formed by electroless copper plating.
Subsequently, as shown in FIG. 7B, a second plating resist having openings on the surface of the second metal thin film 24 according to the wiring pattern to be formed on the substrate surface on which the second metal thin film 24 is formed. 42 is formed. The second plating resist 42 can be formed in the same manner as the first plating resist 40.

In this way, the second metal thin film 24 and the second plating resist 42 are formed on one surface, and the substrate 10 covered with the second insulating film 20 on the other surface is stored in a plating tank with stirring. A third electrolytic metal plating is performed using the second metal thin film 24 as a power feeding layer by dipping in a plating solution. In the present embodiment, electrolytic copper plating was performed as the third electrolytic metal plating. As shown in FIG. 7C, the third plated metal layer 26 is deposited on the second metal thin film 24 exposed from the opening portion of the second plating resist 42 by the third electrolytic metal plating.
Thereafter, the first metal thin film 14 and the second metal thin film 24 exposed by removing the second insulating film 20, the first plating resist 40, and the second plating resist 42 are formed as shown in FIG. Remove by etching. Thereby, it is possible to obtain a wiring substrate 50 in which independent wiring patterns are formed on the upper surface and the lower surface of the substrate 10 as shown in FIG.

In the present embodiment, a method for manufacturing a wiring board 50 in which a wiring pattern is formed by a semi-additive method on each surface (upper surface and lower surface of the substrate 10 shown in the figure) where both side openings of the through hole 12 are opened will be described. However, only the wiring pattern formed on one of the upper and lower surfaces of the substrate 10 is formed by the semi-additive method, and the wiring pattern formed on the other surface is formed by the subtractive method. Of course it is also possible to do.
Further, the removal timing of the first plating resist can be performed between the formation of the first plating metal layer 18 and the stacking of the second insulating film 20. After removing the first plating resist 40 before laminating the second insulating film 20, the second insulating film 20 is laminated so that no gap is formed between the first metal thin film 14 and the first plating metal layer 18. Careful attention is required.

  Although the present invention has been described in detail above based on the embodiments, the present invention is not limited to the above-described embodiments. Although a specific description is omitted, it is a matter of course that even an embodiment in which the above description is appropriately combined belongs to the technical scope of the present invention.

It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 1st Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 1st Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 1st Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 1st Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 2nd Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 2nd Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 2nd Embodiment is applied. It is sectional drawing in the manufacturing process of the wiring board to which the through-hole filling method in 2nd Embodiment is applied. It is process drawing explaining the filling method of the conventional through hole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Board | substrate 12 Through-hole 12a Space part 14 Metal thin film 16 1st insulating film 18 1st plating metal layer 18a Protrusion part 20 2nd insulating film 22 2nd plating metal layer 22a, 24a Recessed part 24 2nd metal thin film 26 3rd plating metal Layer 30 Wiring board 40 First plating resist 42 Second plating resist 50 Wiring board

Claims (7)

A first metal thin film is formed on the entire surface of the substrate including an inner wall surface of a through hole having an opening on one side and the other side of the substrate formed of an insulating material, and the one side of the substrate is formed with a first insulating film. Covering and applying a first electrolytic metal plating using the first metal thin film as a power feeding layer on the other surface side of the substrate, the opening on the other surface side of the through hole is closed with a plating metal, and the first insulation After removing the film, opening one side opening of the through hole, and covering the surface of the first plated metal layer formed on the other side of the substrate with a second insulating film,
At least a space remaining in the through hole after removing the first metal thin film exposed on the inner wall surface of the through hole is filled with a second electrolytic metal plating using the first plating metal layer as a power feeding layer. A method of manufacturing a wiring board, comprising: forming a through electrode that electrically connects one surface side and the other surface side of the substrate.   Prior to performing first electrolytic metal plating using the first metal thin film as a power feeding layer, the method further includes a step of forming a plating resist having an opening pattern identical to a wiring pattern to be formed on the other surface side of the substrate. The method for manufacturing a wiring board according to claim 1, wherein: After forming the second plating metal layer up to the end face position of the one side opening of the through hole,
Forming a second metal thin film on one side of the substrate;
3. The method according to claim 1, further comprising a step of performing third electrolytic metal plating using the second metal thin film as a power feeding layer, and laminating a third plating metal layer on the second metal thin film. The manufacturing method of the wiring board as described.   Prior to performing third electrolytic metal plating using the second metal thin film as a power feeding layer, a plating resist having the same opening pattern as the wiring pattern to be formed on the second metal thin film on the second metal thin film The method of manufacturing a wiring board according to claim 3, further comprising a step of forming the step.   4. The method according to claim 3, further comprising a step of forming a wiring pattern by etching at least one of the first plating metal layer and the third plating metal layer into a required pattern. A method for manufacturing a wiring board.   6. The method of manufacturing a wiring board according to claim 1, wherein the second electrolytic metal plating slows the deposition rate of the plated metal as compared with the first electrolytic metal plating. .   The method for manufacturing a wiring board according to any one of claims 1 to 6, wherein an electrolytic plating solution for via fill is used at least in the second electrolytic metal plating.