The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 30, 1993
Filed:
Jul. 01, 1992
Applicant:
Inventors:
Hiroki Uchida, Hirakata, JP;
Motonobu Kubo, Hirakata, JP;
Masayuki Kiso, Hirakata, JP;
Teruyuki Hotta, Hirakata, JP;
Tohru Kamitamari, Hirakata, JP;
Assignee:
C. Uyemura & Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C23C / ;
U.S. Cl.
CPC ...
106122 ; 106-125 ;
Abstract
A tin or tin-lead alloy electroless plating bath comprising (A) a stannous salt or a mixture of a stannous salt and a lead salt, (B) an acid, (C) thiourea or a thiourea derivative, and (D) a reducing agent is improved by adding (E) a nonionic surfactant and optionally, (F) a cationic surfactant, a nitrogenous heterocyclic compound or a derivative thereof, or alternatively by adding (G) an ammonium or quaternary ammonium ion. From the bath, uniform films of fine grains will chemically deposit on fine pitch printed wiring boards intended for SMT.