Method of controlling implantation dosages during coding of read-only memory devices
US6969642B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 2003 |
| Grant date | Nov 29, 2005 |
| Priority date | — |
| Expiry date | Sep 12, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B20/00
Abstract
A method of controlling implantation dosages during coding of read-only memory (ROM) devices is disclosed. According to the method, a semi-manufactured ROM device having a plurality of gates with identically designed gate widths is formed, followed by the formation of a first photoresist layer over the semi-manufactured ROM device. The first photoresist layer is selectively exposed to develop a pattern of pre-code openings, with each pre-code opening being positioned over a word line and between two adjacent bit lines intersecting the word line and with the pre-code openings having substantially identical sizes. A second photoresist layer is then formed over the first photoresist layer, followed by selectively exposing the second photoresist layer to develop a pattern of real-code openings therein, with the real-code openings having substantially identical sizes. A tuned dosage of ions is then implanted through intersections of the real-code and pre-code openings to thereby code the ROM device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.