Reference

Gold electroless coating of integrated circuits

Gold electroless coating of integrated circuits. (Toshiba Corp.Some chemicals with cas registry numbers like 14263-59-3 and 11143-14-9 are also used., Japan). Jpn. Kokai Tokkyo Koho JP 59006365 A2 13 Jan 1984 Showa, 3 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C23C003-02. APPLICATION: JP 82-111675 30 Jun 1982. DOCUMENT TYPE: Patent CA Section: 56 (Nonferrous Metals and Alloys) Section cross-reference(s): 76 In electroless coating with high-purity Au, products coated with Ni or Ni and B, and heat treated, or products coated with Au by flash plating, the coating solns. (pH 4-7) contg.: (1) complex compd(s). composed of Au compd(s). (contg. at least Au K cyanide) and org. acid such as citric acid and tartaric acid or their salt, (2) a reducing agent (hydrazine hydrate), and (3) NH4Cl are used in th electroless coating. The method forms a highly pure Au coating on products having excellent appearance and improved adhesion, and is useful for producing integrated and large-scale integrated circuits. Thus, a Ni coating (20 m thick, recrystd.) contg. B on a sintered alumina substrate was coated with Au (1 m thick) in an electroless Au coating soln. (pH 6-7, at 45-50°) contg. Au K cyanide 2, Na citrate 50 g/L, and hydrazine hydrate 20 mL/L, heat treated at 200-300° to recrystallize the Au layer, and the Au layer had excellent appearance, adhesion, bonding, and brazing properties as electronic parts. .