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:
Mar. 30, 2004
Filed:
Mar. 19, 2003
Henry Chung, Taipei, TW;
Macronix International Co., Ltd., Hsinchu, TW;
Abstract
A method of manufacturing mask ROM is provided. A buried bit line is formed in a substrate and then a gate and a word line are formed over the substrate. Thereafter, a pre-coding layer with a plurality of pre-coding openings therein is formed over the substrate in a relatively high precision process. The pre-coding openings correspond in position to a plurality of coding regions on the substrate underneath the gate. A filler material is deposited into the pre-coding openings to form a filler layer. A coding mask having a plurality of coding openings is formed over the substrate in a relatively low precision process. The filler material inside the pre-coding openings that correspond in position to the code openings in the coding mask is removed. The coding mask is removed. Finally, a coding ion implant is carried out using the pre-coding layer and the filler layer as mask and hence ions are implanted into the code region through the pre-coding openings.