On-axis air gage focus system
US5087927A · kind A · utility
8Cited by
4References
21Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1990 |
| Grant date | Feb 11, 1992 |
| Priority date | — |
| Expiry date | Jan 31, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7057
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A lithography tool having an improved focus system. The focus system comprises a lens mounted in a nosepiece which defines a chamber. The chamber defines an onifice through which the lens system may see a workpiece. An air supply is provided to supply a regulated and measured air flow to the chamber. By measuring the air flow into the chamber, the rate of air flow through the orifice may be determined. The rate of air flow through the orifice is proportional to the gap between the orifice and a workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.