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:
May. 27, 1986
Filed:
Jun. 05, 1978
Pallab K Chatterjee, Dallas, TX (US);
Al F Tasch, Jr, Richardson, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A MOS read only memory, or ROM, is formed by a process compatible with standard P-channel or N-channel metal or silicon gate manufacturing methods. The ROM is programmed either after the protective nitride layer has been applied and patterned, usually the last step in the slice processing method before electrical testing of the devices, or after the electrical testing of the devices. All potential MOS transistors in the ROM array are initially at a logic '0' or a logic '1'. An electron beam slice printing machine is used to program the selected transistors in the ROM array to change their logic state by exposing the gates of the selected transistors to an electron beam. The gates to be exposed are predetermined by a coding on a magnetic tape which corresponds to the desired ROM code. No electron beam mask is necessary since the beam only exposes in selected areas.