ELECTROLESS COPPER DEPOSITION PROCESS USING GLYOXYLIC-ACID AS A REDUCING AGENT

Glyoxylic acid as an alternative reducing agent for electroless copper plating was investigated. Plating rates and bath stability were superior to that of the formaldehyde bath under standard conditions. The morphologies of deposited copper film were not greatly affected by ethylenediaminetetraacetic acid concentration, and mechanical properties (for instance, the ductility) of deposited films were obtained. The rate of the Cannizzaro reaction with glyoxylate ions was faster than with formaldehyde, but could be reduced by 10 to 40% using KOH instead of NaOH. It was confirmed that the uniformity of hole wall coverage was superior to that of the formaldehyde bath. Glyoxylate ions in the plating bath have no vapor pressure and showed good reducing power in the electroless copper plating:Therefore, glyoxylic acid can replace formaldehyde, and eliminate health and environmental problems resulting from generation of obnoxious fumes.