Precoat composition for organic solderability preservative

Abstract

The present invention provides an improved method of enhancing the solderability of a copper surface comprising the steps of contacting one or more copper surfaces with a pretreatment composition comprising a dilute solution of an aliphatic carboxylic acid and an additive selected from the group consisting of amines and ammonia and thereafter contacting the one or more surfaces with an organic solderability preservative composition. The improved organic solderability preservative process of the invention forms a more uniform coating that has a better appearance and color.

Description

technical field [0001] The present invention relates to an organic solderability protection method for coating copper circuits during the manufacture of printed wiring boards. The improved method of the present invention involves the use of a pre-coat application prior to the primary organic solderability preservative bath to enhance the solderability of the copper surface. Background technique [0002] In the manufacture of printed wiring boards (PWBs) having metal containing components to be soldered, the metal must be protected from oxidation to improve its solderability. Typically, many of these electronic components have copper circuitry on them, and may also have gold wires or other electrical connections that are typically used to connect the electronic component to other electronic components. [0003] Today's methods for protecting copper prior to soldering generally involve a protective coating deposited on the copper. Existing techniques include hot air leveling...

AI Technical Summary

Problems solved by technology

The pretreatment coating described by Wengenroth is believed to maintain the solderability of the copper surface while substantially precluding the adsorption of the gold surface to the OSP coating, which can cause cosmetic defects in the form of rust and may reduce the conductivity of the gold contact surface