Transmission control mask utilized to reduce foreshortening effects
US6258490A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1999 |
| Grant date | Jul 10, 2001 |
| Priority date | — |
| Expiry date | Jul 9, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A transmission controlled mask (TCM) for providing effective and accurate printing of images on a semiconductor wafer is defined. The transmission controlled mask (TCM) of the present invention includes opaque regions, clear regions, and transmission controlled (TC) regions, each region have different transmittance for reducing and/or eliminating the foreshortening which occurs in image printing. By employing the TCM of the present invention and adjusting the exposure time, images of lines and holes may be printed correctly with the same mask. The TCM of the present invention comprises a quartz substrate having a carbon layer and a chrome layer deposited on its surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.