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:
Apr. 26, 2005
Filed:
Jun. 09, 2000
Fujio Kuwako, Urawa, JP;
Fujio Kuwako, Urawa, JP;
Mitsui Mining & Smelting Co., Ltd., Tokyo, JP;
Abstract
A multi-layer printed wiring board having via holes is characterized by having the outer copper wifing circuit lines on a layer of an alkaline refractory metal which is adjacent to a thermosetting resin layer. An alkaline refractory metal which is insoluble is alkaline etching solutions, is electrodeposited on the surface of copper foil, then a thermosetting resin is applied to the surface and semi-cured to obtain a coated copper foil. The coated copper foil is bonded to one or both faces of an inner layer board having wirings on one or both of its faces. Then, the copper foil on a surface of this laminate is removed by alkaline etching, while selectively leaving the alkaline refractor metal layer. A laser beam is used to form via holes in both the alkaline refractory metal layer and the thermosetting resin layer simultaneously. Via holes of the multi-layered printed wiring board can be easily formed using a laser, and adhesion between the outer wirings made from the plated copper and the insulating resin is improved.