Printed wiring board and its manufacture

Abstract

The printed circuit board (39) includes wiring (31) for pads, and a solder mask (38) on the wiring (31), openings (37, 36) for placing solder formed in the solder mask (38) ). The wiring (31) includes a rough surface (32) formed by treating with an etchant containing copper complex and organic acid, and a solder resist layer (38) provided on the rough surface (32). In printed circuit boards, tight and firm contact can be obtained in the solder bump formation area between the fine line wiring and the solder mask to prevent damage to the electrical connection.

Description

[0001] This application is a divisional application based on the application dated July 1, 1999 and the application number 99810416.7. technical field

[0002] The present invention relates to a printed circuit board, and more particularly to a printed circuit board capable of improving the bonding performance and bonding strength between wiring for pads, a solder mask and solder bumps, and a method of manufacturing the same. Background technique

[0003] In recent years, so-called composite multilayer circuit boards have received great attention from the viewpoint of the high-density demand for multilayer circuit boards. Such a composite multilayer circuit board is produced, for example, by the method disclosed in JP-B-4-55555.

[0004] In this method, a photosensitive adhesive for electroless plating is applied to a substrate core, dried, exposed and developed to form an interlayer insulating resin layer with openings as through holes, thereby producing an insulating mater...

Examples

Embodiment 1

[0205] Preparation of Starting Compositions for Electroless Plating Adhesives

[0206] (Adhesive for upper layer)

[0207] [Resin composition A]

[0208] 35 parts by weight of a resin solution formed by dissolving 25% cresol novolak type epoxy resin with a molecular weight of 2500, manufactured by Nippon Kayaku Co., Ltd. in a concentration of 80 wt% DMDG, Toa Gosei.Co., Ltd. 3.15 parts by weight of a photosensitive monomer manufactured under the trade name Aronix M315, 0.5 parts by weight of an antifoaming agent manufactured by Sannopuco Co., Ltd. under the name S-65, and 3.6 parts by weight of NMP were mixed under stirring to prepare the resin Composition A.

[0209] [Resin composition B]

[0210] 12 parts by weight of polyethersulfone (PES), manufactured by Sanyo Kasei Co., Ltd under the trade name Polymerpole, 7.2 parts by weight of epoxy resin particles with an average particle size of 1.0 μm, and the same resin with an average particle size of 0.5 μm 3.09 parts by...

Embodiment 2

[0272] FIG. 33 is a cross-sectional view of the printed circuit board 44 . The manufacturing steps of this example are basically the same as those in Example 1, except that the rough surface of the wiring surface layer for the pad is covered with a metal layer 51, as shown in FIGS. 9 to 12 in step (17). The metal can be nickel, and the metal film layer is formed by electroless plating. The nickel layer thus formed had a thickness of 0.04 µm.

[0273] In this example, on the solder resist layer 38, pass through the nickel-plated layer 52 on the nickel layer 51, and on the opening part of the gold-plated layer 53 on it, form a solder bump (solder body) 54, as steps (18) to (21) shown in Figure 33.

Embodiment 3

[0275] This example is basically the same as Example 2, except that the tin layer of displacement plating is used instead of the nickel layer of electroless plating as the metal layer on the wiring rough surface for covering pads. The tin layer is 0.03 μm thick.

[0001] This application is a divisional application based on the application dated July 1, 1999 and the application number 99810416.7. technical field

[0002] The present invention relates to a printed circuit board, and more particularly to a printed circuit board capable of improving the bonding performance and bonding strength between wiring for pads, a solder mask and solder bumps, and a method of manufacturing the same. Background technique

[0003] In recent years, so-called composite multilayer circuit boards have received great attention from the viewpoint of the high-density demand for multilayer circuit boards. Such a composite multilayer circuit board is produced, for example, by the method disclosed in JP-B-4-55555.

[0004] In this method, a photosensitive adhesive for electroless plating is applied to a substrate core, dried, exposed and developed to form an interlayer insulating resin layer with openings as through holes, thereby producing an insulating mater...

Examples

Embodiment 1

[0205] Preparation of Starting Compositions for Electroless Plating Adhesives

[0206] (Adhesive for upper layer)

[0207] [Resin composition A]

[0208] 35 parts by weight of a resin solution formed by dissolving 25% cresol novolak type epoxy resin with a molecular weight of 2500, manufactured by Nippon Kayaku Co., Ltd. in a concentration of 80 wt% DMDG, Toa Gosei.Co., Ltd. 3.15 parts by weight of a photosensitive monomer manufactured under the trade name Aronix M315, 0.5 parts by weight of an antifoaming agent manufactured by Sannopuco Co., Ltd. under the name S-65, and 3.6 parts by weight of NMP were mixed under stirring to prepare the resin Composition A.

[0209] [Resin composition B]

[0210] 12 parts by weight of polyethersulfone (PES), manufactured by Sanyo Kasei Co., Ltd under the trade name Polymerpole, 7.2 parts by weight of epoxy resin particles with an average particle size of 1.0 μm, and the same resin with an average particle size of 0.5 μm 3.09 parts by...

Embodiment 2

[0272] FIG. 33 is a cross-sectional view of the printed circuit board 44 . The manufacturing steps of this example are basically the same as those in Example 1, except that the rough surface of the wiring surface layer for the pad is covered with a metal layer 51, as shown in FIGS. 9 to 12 in step (17). The metal can be nickel, and the metal film layer is formed by electroless plating. The nickel layer thus formed had a thickness of 0.04 µm.

[0273] In this example, on the solder resist layer 38, pass through the nickel-plated layer 52 on the nickel layer 51, and on the opening part of the gold-plated layer 53 on it, form a solder bump (solder body) 54, as steps (18) to (21) shown in Figure 33.

Embodiment 3

[0275] This example is basically the same as Example 2, except that the tin layer of displacement plating is used instead of the nickel layer of electroless plating as the metal layer on the wiring rough surface for covering pads. The tin layer is 0.03 μm thick.

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