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:
Jan. 04, 1994
Filed:
Oct. 25, 1991
Kurt R Grebe, Beacon, NY (US);
Jack M McCreary, Fayetteville, GA (US);
Darbha Suryanarayana, Vestal, NY (US);
Ho-Ming Tong, Yorktown Heights, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Disclosed is a reworkable circuit .package formed by controlled collapse chip connection ('C4') bonding of integrated circuit chips to circuit cards and boards, and direct chip attachment ('DCA') where an encapsulant is disposed under the chip. The encapsulant offers protection of the C4 connections and a thermal expansion matched to that of the C4 joints. However, most encapsulants interfere with reworkability. The disclosed circuit package overcomes this problem by the provision of a passivating layer of Parylene is reworkable, dry processable, uniformly depositable by vapor phase deposition, forming thin films on facing surfaces at the 3-5 micron film thickness corresponding to the C4 lift-off distance.