Photomask having a transparency-adjusting layer, method of manufacturing the photomask, and exposure method using the photomask
US7001697B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 2003 |
| Grant date | Feb 21, 2006 |
| Priority date | — |
| Expiry date | Jun 3, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70191
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photomask for use in photolithography has substrate, a main pattern at one side of the substrate, and a transparency-adjusting layer at the other side of the substrate. The transparency-adjusting layer has a characteristic that allows it to change the intensity of the illumination incident on the main pattern during the exposure process accordingly. In manufacturing the photomask, a first exposure process is carried out on a wafer using just the substrate and main pattern. The critical dimensions of elements of the pattern formed on the wafer as a result of the first exposure process are measured. Differences between these critical dimensions and a reference critical dimension are then used in designing a layout of the transparency-adjusting layer in which the characteristic of the layer is varied to compensate for such differences.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.