Read-only-memory array with coding after metallization
US5561624A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1995 |
| Grant date | Oct 1, 1996 |
| Priority date | — |
| Expiry date | Jun 26, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B20/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A ROM array with coding after metallization comprises a plurality of first bit lines, a plurality of second bit lines, a plurality of third bit lines, a plurality of word lines, a plurality of first control lines, a plurality of second control lines and a plurality of selecting lines. Memory cells of the ROM array are formed by the intersection of the word lines and the first and second bit lines, wherein the word lines are polysilicon gates and the bit lines are drain/source diffusion regions. The third bit lines are metal lines above the first bit lines. The third bit lines are not wide enough to cover spacings between the first and second bit lines, thus exposing spaces for code implantation. The first and second control lines intersect the first and second bit lines to form a number of switches for controlling data reading paths to The memory cells. The positions and ON/OFF states of the switches are designed to provide at least two data reading paths to each memory cell. Thus, the sensing currents in the bit lines are increased and become more uniform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.