Method for measuring the effectiveness of optical proximity corrections
US5962173A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1997 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Oct 16, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70641
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The effectiveness of various types of optical proximity correction schemes for avoiding line shortening are easily evaluated by imprinting a test pattern on a semiconductor wafer. The pattern includes an easily measurable standard measurement element not susceptible to line shortening and a test element having a series of parallel lines with narrow widths comparable to the widths of the circuit features that are susceptible to line shortening. The test element also includes the same optical proximity correction scheme whose effectiveness is to be measured. The entire test pattern is photolithographed onto the wafer and the lengths of measurement element and the test element are measured and compared to determine the effectiveness of the correction. Several test patterns, each with a different form of optical proximity correction, can be lithographed onto a single wafer for a comparative review of the different correction schemes both in focus and out of focus both positively and negatively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.