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:
Sep. 16, 1997
Filed:
Sep. 07, 1995
United Microelectronics Corporation, Hsinchu, TW;
Abstract
A process for fabricating identification alphanumeric code markings on the substrate of mask ROM devices is disclosed. The fabrication process comprises first forming a deposited layer on the substrate of the mask ROM device. A photoresist layer is then formed on the deposited layer. A photomask layer by is then shaped by forming a pattern on the photoresist layer that reveals the channel regions of the memory cell transistors to be programmed into the blocking state, as well as reveals the graphical pattern of the alphanumeric code marking. An etching procedure then removes the portion of the deposited layer revealing the graphical pattern of the alphanumeric code markings. The photomask layer is then removed. A code implantation procedure may precede or follow the etching procedure to facilitate the programming of the memory cells of the mask ROM device.