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:
Jun. 05, 2001

Filed:

Mar. 30, 1999
Applicant:
Inventors:

Tsutomu Asai, Ageo, JP;

Fujio Kuwako, Urawa, JP;

Shinichi Obata, Ina-machi, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01K 3/10 ;
U.S. Cl.
CPC ...
H01K 3/10 ;
Abstract

In a process producing a multi-layer printed wiring board, an inner core having at least one wiring pattern on its surface and an outer layer of copper foil are laminated with an organic insulating layer interposed therebetween, a via hole is formed using a laser beam, and the outer copper foil and the inner wiring patterns are electrically connected to each other by depositing copper. The process is characterized in that the outer layer of copper foil has a thickness of no more than one-fifth of the thickness of the inner wiring pattern, but will not exceed 7 &mgr;m, preferably 4 &mgr;m. The hole is formed in both the copper foil and the insulating layer simultaneously by irradiating with a laser beam on the outer layer of copper foil.


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