Formaldehyde-free bath for electroless deposition of copper - contains copper salt complexing agent, and formic acid (salts) or addn. prods. as reducing agent

摘要

A bath for the electroless deposition of Cu contains (A) as known a Cu salt a complex former (mixt) and (B) HCOOH, its salts, derivs or its addn. prods. as reducting agent. The salt is pref. Cu formate. The reducing agent is a 1,2 or 3 main gp. salt of HCOOH, NH4COOH, activated HCOOH. The complex former is e.g. a carboxylic acid (salt), phosphonic acid (salt), a polyamine, polyethyleneimine, esp in amounts of 0.05-100g/D. The bath also contains additives, e.g. maleic acid, a fluoride, diphosphate. Deposition is carried out at 25-100 deg.C. ADVANTAGE - The bath is free from HCOH and toxic substances; environmetally acceptable reducing agents are used; a better quality Cu deposit than previously is obtd.