Method and apparatus for real-time, in-situ endpoint detection and closed loop etch process control
US5392124A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1993 |
| Grant date | Feb 21, 1995 |
| Priority date | — |
| Expiry date | Dec 17, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0683
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for detecting an etching endpoint of a film on a substrate whereby a first excitation beam of light having a prescribed wavelength is provided, the first light beam substantially containing only a first harmonic component of light at that wavelength. The first light beam is directed at a prescribed incident angle to an interface between the film and the substrate, the first light beam being reflected off the interface to thereby provide a second light beam, the second light beam containing the first harmonic component of the first light beam and a generated second harmonic component. The generated second harmonic component is detected and a first output signal representative thereof is provided. A generated second harmonic component reference of the first light beam is produced and a second output signal representative of a generated second harmonic component reference is provided. The detected second harmonic component of the first light beam is normalized, as a function of the first and second output signals, in real-time, and a third output signal representative of an occurrence of a prescribed change in the normalized detected second harmonic component is…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.