Real time measurement of etch rate during a chemical etching process
US5788801A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 1997 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Mar 27, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/26
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A contactless method and apparatus for real-time in-situ monitoring of a chemical etching process during etching of at least one wafer in a wet chemical etchant bath are disclosed. The method comprises the steps of providing two conductive electrodes in the wet chemical bath, wherein the two electrodes are proximate to but not in contact with a wafer; monitoring an electrical characteristic between the two electrodes as a function of time in the etchant bath of the at least one wafer, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process; and recording a plurality of values of the electrical characteristic as a function of time during etching. From the plurality of recorded values and corresponding times, instantaneous etch rates, average etch rates, and etching end points may be determined. Such a method and the apparatus therefor are particularly useful in a wet chemical etch station.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.