Abstract: An electroless gold plating composition comprises an aqueous solution of alkali metal gold cyanide, alkali metal cyanide, alkali metal hydroxide, a reducer selected from borohydrides and alkyl amine boranes, and a stabilizer having the formula ##STR1## wherein R.sub.1 is --COOH, --OH, --CH.sub.2 OH, or --SO.sub.3 H (or an alkali metal salt thereof), R.sub.2 is --COOH, --OH, --Cl, --H, (or an alkali metal salt thereof) and is disposed in the 2, 5, or 6 ring position, and --NO.sub.2 is in the 3 or 4 ring position. This composition has a pH of 12.5-14.0, is heated at 85.degree.-95.degree. C., and operates at an oxidation/reduction potential of -550 to -700 millivolts to produce high purity gold deposits of amorphous structure and good hardness for electronic applications. The composition may be replenished as many as ten turnovers.
Type:
Grant
Filed:
May 15, 1989
Date of Patent:
July 14, 1992
Assignee:
Technic, Inc.
Inventors:
Zoltan F. Mathe, Augustus Fletcher, deceased