Method for analyzing copper ion concentration in electroless tin, lead or their alloy plating bath

摘要

PURPOSE:To offer the method for analyzing the copper ion concn. in an electroless plating bath of tin, lead or alloy of these metals for copper or copper alloy in order to easily and surely control the electroless plating bath by easily and accurately analyze the copper ion in the plating bath. CONSTITUTION:The electroless plating of tin, lead or allay of these metals on copper or copper alloy contains water-soluble tin salt and/or water-soluble lead salt, an acid which dissolves these salts and thiourea. An oxidizer which can decompose the thiourea is added to this bath to oxidize and decompose thiourea in the bath as well as to oxidize univalent copper ion to bivalent copper ion. Then the concn. of whole bivalent copper ion including the oxidized copper ion is measured by colorimetry.