METHOD FOR MANUFACTURE OF PRINTED CIRCUIT BOARDS

摘要

A method of preparing printed circuit boards in which the solder mask (24) is applied over a thin layer (''smut'') of tin covering the copper circuit traces, the tin layer being that which remains after stripping tin or tin-lead alloy etch resist (22). This represents a significant cost saving as compared with processes in which the tin-lead alloy (20) is completely stripped leaving bare copper to which the solder mask (24) is applied in the SMOBC type of circuit board.