Method and apparatus for reducing OPC model errors
US7325225B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Oct 5, 2005 |
| Grant date | Jan 29, 2008 |
| Priority date | — |
| Expiry date | Oct 5, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/68
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
It is important to assess and reduce errors that arise in mask correction techniques such as optical proximity correction. A preliminary mask is obtained using an OPC model. An etched wafer is created from the preliminary mask using lithography, and first and second critical dimensions (CD) are measured on the wafer and. An edge placement error (EPE) is determined that corresponds to a difference between a measured value and a desired value of the second CD. These steps are repeated for a plurality of different values of the first CD, and of for each of the values of, the measured value of the second CD is correlated with its corresponding value on the mask as predicted by the OPC model. Δ difference ΔCD is obtained between the difference of the mask CDs calculated by interpolation of wafer CD measurements and by OPC model predictions and is transformed into an OPC model error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.