X-ray mask blank process
US4604292A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1985 |
| Grant date | Aug 5, 1986 |
| Priority date | — |
| Expiry date | Apr 26, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/168
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An improved process, optimizing quality and growth rate with independent control of residual stress, is disclosed for the growing of membranes for use as X-ray lithography mask blanks. The process comprises providing a mounting fixture and a low-cost substrate material thereon, cooling the substrate to about the boiling point of hydrogen by passing a liquid coolant in contact with the fixture, depositing by a low-temperature plasma-enhanced method a thin membrane onto the cooled substrate, removing the substrate and the thereon deposited membrane from the fixture, and allowing the substrate thermally to expand by gradually assuming ambient room temperature, whereby the membrane will acquire optimum tensile stress. Preferably, the low-cost substrate is low grade industrial silicon and the membrane is formed of boron nitride, silicon carbide, silicon nitride, amorphous silicon, diamondlike carbon, aluminum oxide, beryllium and silicon oxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.