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. 09, 1991
Filed:
Aug. 11, 1989
Dale W Swanson, Yorba Linda, CA (US);
James J Licari, Whittier, CA (US);
Rockwell International Corporation, El Segundo, CA (US);
Abstract
A microelectronic device is rendered resistant to reverse engineering by encapsulating it in a dual layer encapsulant. The inner layer is compatible with the operation of the device, and has a greater resistance to chemical attack then does the device. The outer layer includes a filler of barium sulfate and gadolinium oxide, to absorb X-rays and N-rays respectively, is more resistant to chemical attack than the inner layer, and includes a groove around its periphery, to preferentially allow chemical attack radially. A full chemical attack damages the device beyond usable inspection, but a partial chemical attack is insufficient to remove X-ray and N-ray concealment.