Glass substrate-holding tool and method for producing an EUV mask blank by employing the same
US8967608B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2012 |
| Grant date | Mar 3, 2015 |
| Priority date | — |
| Expiry date | Sep 10, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S269/903
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A glass substrate-holding tool employed during the production of a reflective mask blank for EUV lithography includes an electrostatic chuck and a mechanical chuck. A caught and held portion of a glass substrate caught and held by the electrostatic chuck, and pressed portions of the glass substrate pressed by the mechanical chuck are located outside a quality-guaranteed region on each of a film deposition surface and a rear surface of the glass substrate. The sum of a catching and holding force applied to the glass substrate by the electrostatic chuck and a holding force applied to the glass substrate by the mechanical chuck is at least 200 kgf. A pressing force per unit area applied to the glass substrate by the mechanical chuck is at most 25 kgf/mm2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.