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:
Jul. 07, 1998
Filed:
May. 14, 1996
Masaharu Shirai, Kusatsu, JP;
Yutaka Tsukada, Shiga-ken, JP;
International Business Machines Corporation, Armonk, NY (US);
Abstract
To inhibit the migration of conductive layers in a multilayer chip carrier, e.g., a multilayer printed circuit board, an optically cured layer 13, which is an anti-migration layer, is formed in an insulating layer 12 located between a first conductive layer 8 and a second conductive layer 6. Such a structure is formed by thinning, e.g., grinding down, a first insulating layer, leaving about half the thickness of the first insulating layer. This first insulating layer is selectively optically irradiated with actinic radiation to form an optically cured layer. Via holes are etched into the non-irradiated portions of the first insulating layer. Thereafter, a second insulating layer is formed on the first insulating layer, and it too is selectively optically irradiated with actinic radiation. Via holes are etched into the non-irradiated portions of the second insulating layer, directly over the via holes in the first insulating layer, and the second insulating layer is also thinned.