System for specifying critical dimensions, sequence numbers and revision levels on integrated circuit photomasks
US4442188A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 2, 1981 |
| Grant date | Apr 10, 1984 |
| Priority date | — |
| Expiry date | Jan 2, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/44
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A system for specifying critical dimensions, mask sequence levels, and mask revision levels on integrated circuit photomasks and chips involving use of a patterned array of geometric regions containing preselected indicia in each region corresponding to the mask sequence number for an associated photomask. The preselected indicia may be either a critical diemension pattern to integrate the mask sequence indicia with the critical dimension specification or a mask revision level code to integrate the mask sequence number with the revision level, or a combination of both a critical dimension pattern and a mask revision level code. In the latter case the mask revision level code is integrated with the critical dimension pattern to conserve space on the photomask and the IC chip.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.