X-ray lithographic mask blank with reinforcement
US5199055A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1992 |
| Grant date | Mar 30, 1993 |
| Priority date | — |
| Expiry date | Jul 6, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG21K1/06
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Proposed is a high-precision X-ray lithographic mask blank with reinforcement free from warping or distortion. The mask blank is an integral body comprising: (a) a frame made from a silicon wafer; (b) a membrane of an X-ray permeable material such as silicon carbide adhering to and supported by one surface of the frame; and (c) a reinforcing member made from a single crystal of silicon adhesively bonded to the other surface of the frame with (d) a layer of silicon oxide intervening between the frame and the reinforcing member. The mask blank can be prepared in a process of first forming a layer of silicon oxide on the surface of the silicon wafer and/or reinforcing member prior to deposition of the X-ray permeable film on the silicon wafer and heating them together at a temperature of 800.degree. C. or lower while they are in direct contact with each other with the silicon oxide layer intervening therebetween.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.