Twisted wordline strapping arrangement
US6611062B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 1, 2002 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | Apr 1, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B12/50
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A high density wordline strapping arrangement is obtained by routing three primary metal-2 wordline straps in the same space as four polysilicon wordline, and routing the fourth wordline strap in a metal-4 layer over the primary metal-2 wordline straps. Stitches in metal-3 connect metal-2 primary wordline straps to metal-4 wordline straps. Therefore, contact spacing and metal pitch limitations are relaxed to allow four metal wordline straps to occupy the same pitch as four polysilicon wordlines. The wordlines are twisted to keep the fully balanced and to minimise coupling between wordline straps and neighbouring power and signal lines. Hence, a smaller memory cell array can be formed according to the wordline packing arrangement of the present invention.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.