Apparatus and method for real-time measurement of thin film layer thickness and changes thereof
US5450205A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1993 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | May 28, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0683
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A new technique has been developed to measure etching or deposition rate uniformity in situ using a CCD camera which views the wafer during plasma processing. The technique records the temporal modulation of plasma emission or laser illumination reflected from the wafer; this modulation is caused by interferometry as thin films are etched or deposited. The measured etching rates compare very well with those determined by Helium-Neon laser interference. This technique is capable of measuring etching rates across 100-mm or larger wafers. It can resolve etch rate variations across a wafer or within a die. The invention can also be used to make endpoint determinations in etching operations as well as measuring the absolute thickness of thin films.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.