Method and apparatus for normalizing a laser beam to a reflective surface
US5648847A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 7, 1995 |
| Grant date | Jul 15, 1997 |
| Priority date | — |
| Expiry date | Mar 7, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K26/043
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
In an etch monitor system, a method and apparatus for adjusting the angle of incidence to normal between a laser beam and a reflective surface, such as a silicon wafer, includes a rotatable mirror having a pinhole formed therethrough, the rotatable mirror moveably mounted to be positioned in a first location within a light path and a second location out of said light path. When the rotatable mirror is located in the light path, the pinhole allows a beam of the laser beam to pass from a laser source to the reflective surface. If the beam is normal to the reflective surface, the beam is directed back toward the laser source through the pinhole. If the beam is not normal to the reflective surface, the beam is reflected by the rotatable mirror to a target, allowing observation on a lit spot of the target to enable normalization by making appropriate adjustments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.