Methods for monitoring and controlling deposition and etching using p-polarized reflectance spectroscopy
US5552327A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1994 |
| Grant date | Sep 3, 1996 |
| Priority date | — |
| Expiry date | Aug 26, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/26
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Deposition or etching of a layer on a substrate is monitored by impinging P-polarized light on the layer during deposition at an angle which is approximately the Brewster's angle for the substrate, and detecting radiation which is reflected from the structure during deposition. In heterodeposition, a quarter wavelength interference signal having a predetermined periodicity is monitored. Maxima and/or minima in the quarter wavelength ratio are monitored and an amplitude modulated fine signal which is superimposed on the quarter wavelength interference signal is also monitored. The deposition process is controlled based on the monitored quarter wavelength interference signal, ratio of the maxima and/or minima, fine signal, fine signal amplitude modulation and/or combinations thereof by comparing the signals to a reference derived from mathematical models or empirical data. A heterodeposition or etching can also be used to calibrate a homodeposition or etching. Scattered light may also be correlated to the reflected light to reduce the scattering component of the reflected light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.