Narrow band excimer laser and wavelength detecting apparatus
US5404366A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 1994 |
| Grant date | Apr 4, 1995 |
| Priority date | — |
| Expiry date | Feb 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/08004
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A narrow band excimer laser and a wavelength detecting apparatus are suitable for use as a light source of a reduction projection aligner of a semiconductor device manufacturing apparatus. In the excimer laser, the ruling direction and the beam expanding direction of a prism beam expander are made substantially coincide with each other, and a polarizing element causing selective oscillation of a linearly polarized light wave substantially parallel with the beam spreading direction of a prism beam expander is contained in a laser cavity. A window at the front or rear side of a laser chamber is disposed such that the window make a Brewster's angle with respect to the axis of the laser beam in a plane containing the beam expanding direction of the prism expander and the laser beam axis. An anti-reflection film which selectively prevents reflection of a polarized light component substantially parallel to the direction of beam expanding of a prism beam expander is coated on one surface of a prism that constitutes the prism beam expander. The wavelength detecting apparatus is constructed to input a reference light and a light to be detected upon the etalon. The light transmitting through…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.