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:
Aug. 28, 2001
Filed:
May. 28, 1999
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
Disclosed are a printed wiring board having micro-via holes highly reliable for conduction and a method of making the micro-via hole by providing a coating or sheet of an organic substance containing 3 to 97% by volume of at least one selected from a metal compound powder, a carbon powder or a metal powder having a melting point of at least 900° C. and a bond energy of at least 300 kJ/mol on a copper foil as an outermost layer of a copper-clad laminate having at least two copper layers, or providing a coating or sheet of the same after oxidizing a copper foil as an outermost layer, irradiating the coating or sheet with a carbon dioxide gas laser at an output of 20 to 60 mJ/pulse, thereby removing a micro-via-hole-forming portion of at least the copper foil as the outermost layer, then irradiating micro-via-hole-forming portions of the remaining layers with a carbon dioxide gas laser at an output of 5 to 35 mJ/pulse to make a micro-via hole which does not penetrate through the copper foil in a bottom of the micro-via hole, and electrically connecting the copper foil as the outermost layer and the copper foil in the bottom of the micro-via hole with a metal plating or an electrically conductive coating composition.