JP2018163904A - Manufacturing method of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a printed wiring board having high insulation reliability of a metal post.SOLUTION: After electrolytic plating for forming a convex pads 82 is completed, a solder resist layer 70 is formed. Therefore, insulation reliability of a first conductor layer 34 exposed from an opening 71 of the solder resist layer is increased, and a short circuit between metal posts 88 formed on the first conductor layer 34 is unlikely to occur.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a printed wiring board having a convex pad and a metal post.

Patent document 1 is disclosing the manufacturing method of the printed wiring board which has a metal post and a lip chip pad. In Patent Document 1, a metal post is formed on a solder resist layer by plating after the formation of a solder resist layer having an opening exposing a Philip chip pad.

JP-A-2006-21475

[Problems of Patent Document 1]
In Patent Document 1, since a metal post (convex pad) is formed on the solder resist layer by plating after the formation of the solder resist layer having an opening exposing the Philip chip pad, the insulation reliability of the Philip chip pad is improved. It seems difficult.

The printed wiring board manufacturing method according to the present invention includes a first conductor layer on the metal foil side, a second conductor layer on the opposite side of the metal foil, and the first conductor layer on a support plate including the metal foil. Forming a resin insulation layer having via conductors connecting the second conductor layer and the support plate, separating the metal foil and the resin insulation layer, and forming a convex pad on the metal foil Forming a first plating resist having an opening for forming, forming a convex pad with an electrolytic plating film in the opening for forming the convex pad of the first plating resist, and removing the first plating resist Removing the metal foil in the non-formed portion of the convex pad; forming a solder resist layer on the resin insulating layer, the first conductor layer, and the metal post; and Reduce the thickness, Exposing an upper portion of the convex pad; forming an opening for exposing the first conductor layer providing a metal post on the solder resist layer; and forming a seed layer on the solder resist layer in the opening. Forming a second plating resist having an opening for forming a metal post on the seed layer; forming a metal post by an electrolytic plating film in the opening for forming the metal post; Removing the plating resist and removing the seed layer in the non-formed portion of the metal post.

[Effect of the embodiment]
According to the embodiment of the present invention, after the convex pad is formed by electrolytic plating, the solder resist layer is formed, the thickness of the solder resist layer is reduced, and the upper portion of the convex pad is exposed, and then the solder resist layer is exposed. An opening for exposing a conductor circuit on which a metal post is provided is formed, and a metal post is formed in the opening. That is, the solder resist layer is formed after the electrolytic plating for forming the convex pad is completed. For this reason, the insulation reliability of the 1st conductor layer exposed from the opening of a soldering resist layer becomes high, and it is hard to generate | occur | produce the short between metal posts formed on a 1st conductor layer.

1A and 1B are manufacturing process diagrams of a printed wiring board according to the first embodiment of the present invention, and FIG. 1C is a printed wiring board according to a modification of the first embodiment. It is sectional drawing. Manufacturing process diagram of printed wiring board of first embodiment Manufacturing process diagram of printed wiring board of first embodiment Manufacturing process diagram of printed wiring board of first embodiment Manufacturing process diagram of printed wiring board of second embodiment

[First embodiment]
FIG. 1A is a cross-sectional view of the printed wiring board according to the first embodiment.
The printed wiring board 10 includes a resin insulating layer 50 having a first surface F and a second surface S opposite to the first surface. The resin insulating layer 50 is formed of a resin containing inorganic particles and does not have a core material. The resin insulating layer 50 has the first conductor layer 34 formed on the first surface F side and the second conductor layer 58 formed on the second surface S side. The first conductor layer 34 and the second conductor layer 58 are connected via a via conductor 60 formed by filling the through hole 51 formed in the resin insulating layer 50 with plating. The first conductor layer 34 is formed such that the side surface 34D and the lower surface 34B are embedded in the resin insulating layer 50, and the upper surface 34U of the first conductor layer 34 is formed on the same plane as the first surface F of the resin insulating layer. . The second conductor layer 58 is formed so as to be exposed from the second surface S of the resin insulating layer 50. A solder resist layer 70 is formed on the first surface F of the resin insulating layer 50 and on the first conductor layer 34. On the first conductor layer 34, a convex pad 82 for mounting an electronic component such as an IC chip is provided. The upper part of the convex pad 82 is exposed through the solder resist layer 70. An opening 71 for exposing the first conductor layer 34 is formed in the solder resist layer 70. A metal post 88 is formed on the first conductor layer 34 exposed at the opening 71.

FIG. 1B shows an application example of the printed wiring board 10 of the first embodiment. A printed wiring board (upper board) 210 is mounted on the printed wiring board 10 via a metal post 88 and solder 104. An IC chip 212 is mounted on the convex pad 82 of the printed wiring board 10 via the solder 102. The printed wiring board 10 of the first embodiment has high connection reliability with the IC chip 212 because the convex pad 82 protrudes from the solder resist layer 70.

[Method for Manufacturing Printed Wiring Board of First Embodiment]
2 to 4 show a method for manufacturing a printed wiring board according to the first embodiment.
A first conductor layer 34 is formed on the support plate 30 including the copper foil 32. A resin insulating layer 50 having a first surface F on the copper foil side and a second surface S opposite to the first surface is formed on the copper foil 32 and the first conductor layer 34. Then, a through hole 51 reaching the first conductor layer 34 is formed by a laser, and a seed layer 53 is formed in the through hole 51 and on the second surface S of the resin insulating layer 50. A plating resist (not shown) is formed, electrolytic plating 54 is formed in a portion where the plating resist is not formed, a via conductor 60 is formed in the through hole 51 by electrolytic plating, and a second conductor layer is formed on the resin insulating layer 50. 58 is formed. The seed layer 53 in the portion where the second conductor layer is not formed is peeled off (FIG. 2A).

The copper foil 32 and the resin insulating layer 50 are separated from the support plate 30 (FIG. 2B). On the resin insulating layer 50 and the first conductor layer 34, a first plating resist 62 having an opening 62a for forming a convex pad is formed (FIG. 2C). Within the opening 62a for forming the convex pad of the first plating resist 62, a copper plating film 84 constituting the convex pad 82 is formed on the first conductor layer 34 by electrolytic copper plating using the copper foil 32 (see FIG. FIG. 2 (D)). The first plating resist 62 is removed (FIG. 2E). The copper foil 32 of the non-formation part of the 1st conductor layer 34 is peeled (FIG.2 (F)).

A solder resist composition 70e is formed on the resin insulating layer 50, the first conductor layer 34, and the convex pad 82 (FIG. 3A). The thickness of the solder resist composition 70e is reduced by etching, and the upper portion of the convex pad 82 is exposed from the solder resist composition 70e (FIG. 3B). The solder resist composition 70e is exposed to form the solder resist layer 70, and the uncured solder resist composition 70e remains in the non-exposed portion (FIG. 3C). The solder resist layer 70 and the solder resist composition 70e are developed. An opening 71 exposing the pad 73 is formed in the solder resist layer 70 on the first surface F side (FIG. 3D).

By blasting, the surface of the solder resist layer 70 and the surface of the first conductor layer 34 in the opening 71 are roughened to form a seed layer (FIG. 3E). A seed layer 52 is formed by electroless copper plating on the surface of the solder resist layer 70, in the openings 71, and on the exposed portions of the convex pads 82 (FIG. 4A). A second plating resist 94 having an opening 94a for forming a metal post is formed on the seed layer 52 (FIG. 4B). A copper plating film 87 constituting the metal post 88 is formed by electrolytic copper plating using the seed layer 52 on the first conductor layer 34 in the opening 94a for forming the metal post of the second plating resist 94 ( FIG. 4 (C)). The second plating resist 94 is removed (FIG. 4D). The seed layer 52 in the non-formed portion of the metal post 88 is peeled off, and the printed wiring board 10 is completed (FIG. 1A).

An IC chip 212 is mounted on the convex pad 82 via the solder 102. A printed wiring board (upper substrate) 210 is mounted on the metal post 88 via the solder 104 (FIG. 1B).

According to the method for manufacturing a printed wiring board of the first embodiment, after the convex pad 82 is formed by electrolytic plating, the solder resist composition 70e is formed, and the thickness of the solder resist composition 70e is reduced. After the upper portion of 82 is exposed, an opening 71 is formed to expose the first conductor layer 34 constituting the pad 73 for providing the metal post 88 on the solder resist layer 70. That is, the solder resist layer 70 is formed after the electrolytic plating for forming the convex pad 82 is completed. For this reason, the insulation reliability of the 1st conductor layer 34 exposed from the opening 71 of the soldering resist layer 70 becomes high, and the short circuit between the metal posts 88 formed on the 1st conductor layer 34 does not occur easily.

[Modification of the first embodiment]
FIG. 1C shows a printed wiring board 110 according to a modification of the first embodiment.
In the printed wiring board 110, the second resin insulation layer 150 is formed on the second surface S of the resin insulation layer 50, and the third conductor layer 158 is formed on the second resin insulation layer 150. The second conductor layer 58 and the third conductor layer 158 are connected via a via conductor 160 formed in the second resin insulation layer 150.

[Method for Manufacturing Printed Wiring Board of Second Embodiment]
FIG. 5 shows a method for manufacturing a printed wiring board according to the second embodiment.
In the manufacturing method of the second embodiment, the manufacturing steps from FIG. 2A to FIG. 2F are the same as those of the first embodiment.
A solder resist composition 70e is formed on the resin insulating layer 50, the first conductor layer 34, and the convex pad 82 shown in FIG. 2F (FIG. 5A). And a soldering resist composition is hardened by exposure processing or heat processing, and soldering resist layer 70 is formed (Drawing 5 (B)).

The thickness of the solder resist layer 70 is reduced by blasting, and the upper portion of the convex pad 82 is exposed from the solder resist layer 70 (FIG. 5C). On the solder resist layer 70, a mask 92 having an opening forming through hole 92a exposing the pad is placed (FIG. 5D). An opening 71 for exposing the pad 73 is formed under the through hole 92a by blasting (FIG. 5E). The mask 92 is removed (FIG. 5F). The subsequent steps are the same as the steps after FIG. 3E of the first embodiment.

According to the printed wiring board manufacturing method of the second embodiment, after the convex pad 82 is formed by electrolytic plating, the solder resist layer 70 is formed, the thickness of the solder resist layer 70 is reduced, and the convex pad 82 is formed. After the upper portion is exposed, an opening 71 for exposing the first conductor layer 34 constituting the pad 73 is formed in the solder resist layer 70. That is, the solder resist layer 70 is formed after the electrolytic plating for forming the convex pad 82 is completed. For this reason, the insulation reliability of the pad 73 exposed from the opening 71 of the solder resist layer 70 becomes high, and a short circuit between the metal posts 88 formed on the pad 73 hardly occurs.

DESCRIPTION OF SYMBOLS 10 Printed wiring board 30 Support plate 32 Copper foil 34 1st conductor layer 50 Resin insulation layer 52 Seed layer 58 2nd conductor layer 60 Via conductor 62 1st plating resist 62a Opening 70e Solder resist composition 70 Solder resist layer 71 Opening 73 Pad 82 Convex pad 88 Metal post 92: Mask 94 Second plating resist 94a Opening F First surface S Second surface

Claims (5)

A method of manufacturing a printed wiring board,
A via conductor connecting the first conductor layer on the metal foil side, the second conductor layer on the opposite side of the metal foil, and the first conductor layer and the second conductor layer on a support plate including the metal foil. Forming a resin insulation layer having
Separating the support plate from the metal foil and the resin insulating layer;
Forming a first plating resist having an opening for forming a convex pad on the metal foil;
Forming a convex pad with an electrolytic plating film in the opening for forming the convex pad of the first plating resist;
Removing the first plating resist;
Removing the metal foil in the non-formed portion of the convex pad;
Forming a solder resist layer on the resin insulating layer, the first conductor layer, and the metal post;
Reducing the thickness of the solder resist layer to expose the top of the convex pad;
Forming an opening for exposing the first conductor layer to provide a metal post in the solder resist layer;
Forming a seed layer on the solder resist layer in the opening;
Forming a second plating resist having an opening for forming a metal post on the seed layer;
Forming a metal post by an electrolytic plating film in the opening for forming the metal post;
Removing the second plating resist;
Removing the seed layer in the non-formed portion of the metal post. It is a manufacturing method of the printed wiring board of Claim 1,
Before forming the seed layer, the surface of the solder resist layer and the inside of the opening are roughened. It is a manufacturing method of the printed wiring board of Claim 1,
Reducing the thickness of the solder resist layer is performed by etching,
Forming the opening for exposing the first conductor layer in the solder resist layer is performed by exposure and development. It is a manufacturing method of the printed wiring board of Claim 1,
Reducing the thickness of the solder resist layer is performed by blasting,
Forming the opening exposing the first conductor layer in the solder resist layer is performed by blasting using a mask. It is a manufacturing method of the printed wiring board of Claim 4,
Before reducing the thickness of the solder resist layer, the solder resist layer is cured.

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