Patent ID: 8871631
Filing Date: 2014-10-28
Classification: B23K,H01L

Abstract:
1. A method of forming a solder deposit on a substrate comprising the following steps: a. provide a substrate including a copper or copper alloy surface that includes at least one inner layer contact pad, b. form an opening for the at least one inner layer contact pad extending through the copper surface, c. contact the entire substrate surface including the opening and the at least one inner layer contact pad with a solution suitable to provide a conductive layer on the substrate surface, d. deposit and pattern a resist layer whereby the at least one inner layer contact pad is exposed, e. electroplate a solder deposit layer consisting of tin or tin alloy into the openings, f. remove the resist layer, g. remove the bare conductive layer which is not covered by a solder deposit layer and the copper or copper alloy surface beneath said conductive layer which is not covered by a tin or tin alloy layer by etching wherein the solder deposit layer h. apply a solder resist layer and form solder resist openings to expose the solder deposit layer.