PRINTED WIRING BOARD MANUFACTURING METHOD

PURPOSE:To improve reliability by eliminating selectively an overhung section of a second conductor layer remaining with a solder layer by chemical etching after an etching treatment of a first conductor layer which forms a wiring structure. CONSTITUTION:A copper foil 2 (first conductor layer) is pa...

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Bibliographic Details
Main Authors NOHARA SHOZO, WATABE YASUO, TOBA RITSUJI
Format Patent
LanguageEnglish
Published 05.06.1991
Subjects
CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS
ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
PRINTED CIRCUITS
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Summary:PURPOSE:To improve reliability by eliminating selectively an overhung section of a second conductor layer remaining with a solder layer by chemical etching after an etching treatment of a first conductor layer which forms a wiring structure. CONSTITUTION:A copper foil 2 (first conductor layer) is pasted to both sides of a base material 1 where a through hole 3 is bored. Then, a copper plating layer (first conductor layer) is formed so that the copper foil 2 may be electrically connected. Furthermore, a resist 5 is coated to mask thereon. On an exposed region from the resist 5 of the copper plating layer 4 and the inner periphery section of the through hole 3 is formed to make a diffusion preventing layer 6 (second conductor layer) made of nickel or the like. A solder plating layer 7 is applied to the surface of the diffusion preventing layer 6. Then, the resist 5 is scaled off and subjected to etching treatment. Furthermore, an overhung section 6a of the diffusion preventing layer 6 is selectively removed by the application of a nickel etching agent. Then, an overhung section 7a of the solder plating layer 7 is eliminated by heating in the next process.
Bibliography:Application Number: JP19890270767