Flux-removing aqueous cleaning composition and method of use

Abstract

An aqueous cleaning composition which is capable of removing soldering flux residues, particularly water-soluble flux residues, from a surface of an electronic assembly without leaving significant amounts of white residue on the surfaces of cleaning equipment used in the flux-removal process, contains: (A) a flux-removing portion containing an alkaline salt component composed of at least one potassium salt; and (B) an aqueous portion in which the flux-removing portion is disposed. The composition has a non-potassium alkali metal content of no greater than about 5% by weight. Preferably, the alkaline salt component consists essentially of a potassium salt or mixture of potassium salts, most preferably potassium carbonate or a mixture of potassium carbonate salts. A method of substantially removing soldering flux residues from an electronic assembly surface without leaving significant amounts of white residue on surfaces of cleaning equipment used in the flux-removal method involves applying the aforementioned cleaning composition onto the electronic assembly surface for a period of time sufficient to substantially saponify the flux residues so as to form saponified flux residues, and then removing the saponified flux residues from the electronic assembly surface.