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.

Date of Patent:
Nov. 05, 2002

Filed:

Jan. 08, 2001
Applicant:
Inventors:

Takeo Kuramoto, Tokyo, JP;

Masataka Watabe, Tokyo, JP;

Satoshi Noda, Tokyo, JP;

Takashi Shoji, Saitama, JP;

Takekazu Sakai, Saitama, JP;

Assignee:

Showa Denko K.K., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 2/348 ; H01L 2/352 ; H01L 2/940 ;
U.S. Cl.
CPC ...
H01L 2/348 ; H01L 2/352 ; H01L 2/940 ;
Abstract

A method of forming a solder film on a metallic surface such as a pad of a metallic circuit of a printed circuit board and a lead frame of electronic parts, which is capable of forming a precise and fine pattern and which comprises selectively imparting tackiness to only a predetermined part of the metallic surface by means of a tacky layer-forming solution containing at least one compound selected from benzotriazole derivatives, naphthotriazole derivatives, imidazole derivatives, benzoimidazole derivatives, mercaptobenzothiazole derivatives, benzothiazole thiofatty acid derivatives, and triazine derivatives, adhering a powdered solder to the resulting tacky part, and then melting the solder by heating to thereby form a solder film.


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