Laser interferometer system for monitoring and controlling IC processing
US4927485A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 1988 |
| Grant date | May 22, 1990 |
| Priority date | — |
| Expiry date | Jul 28, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/22
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A laser end point detector incorporating adjustable-focus, variable-orientation detection optics for monitoring different types of structures such as laser-transparent thin films, isolated trenches or holes and patterned arrays of trenches or holes is disclosed. A collector lens package comprising a laser and a focusing lens are mounted in a hole in a collector lens which is pivotally mounted for selectively focusing zero, first and higher orders of diffractions reflected from the wafer onto an associated detector to monitor the etching of different types of structures. For example, zero order diffraction signals are used to monitor the etching of large target areas in transparent thin films or of non-patterned trenches or holes. First order (or higher) diffraction signals are used for monitoring the etching of patterned features which effect a two-dimensional diffraction grating, such as the capacitor holes in dynamic random access memories.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.