Modulated exposure mask and method of using a modulated exposure mask
US6613498B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1999 |
| Grant date | Sep 2, 2003 |
| Priority date | — |
| Expiry date | Sep 16, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70216
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photolithographic process includes providing a layer of photoresistive material on a target substrate. Radiation is transmitted to the photoresistive material through a layer of absorbing material that absorbs the radiation with a transmittance proportional to the thickness of the absorbing material. A surface relief structure is formed in the absorbing material, so that the photoresistive material is only partially exposed in a pattern corresponding to the surface relief structure. Thus, when the photoresistive material is developed, it has a surface relief structure corresponding to the surface relief structure in the absorbing material. Etching the developed photoresistive material and target substrate then forms a surface relief structure in the target substrate that corresponds to the surface relief structure in the developed photoresistive material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.