Method to etch chrome for photomask fabrication
US7754394B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 2006 |
| Grant date | Jul 13, 2010 |
| Priority date | — |
| Expiry date | Mar 28, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/80
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Methods for manufacturing a photomask, such as a chrome on glass photomask and a phase shift photomask are provided. A selective main chrome etch and a selective chrome overetch in the fabrication process provides a photomask having improved image quality and provides nominal image size control and image size uniformity across the photomask within current process flows and manufacturing steps. The selective etch process utilizes a main etch where the resist etch selectivity (amount of chrome removed to resist removed) is higher than in the overetch step in which the etch is more selective to removal of the resist layer relative to the chrome layer. To control the etch selectivities the composition of the etchant chemistry and/or the etchant reactor hardware settings (power, voltage, etc.) can be adjusted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.