Optics: measuring and testing – By particle light scattering – With photocell detection
Patent
1990-12-26
1993-07-06
Turner, Samuel A.
Optics: measuring and testing
By particle light scattering
With photocell detection
356352, G01B 902
Patent
active
052258882
ABSTRACT:
An interferometer (18 or 40) is used to identify trace constituents in a plasma during processing semiconductor devices such as transistors. Light emissions collected from the processing chamber (10) are collimated by lens (14) and transmitted to the interferometer (18 or 40) which selectively allows therethrough particular wavelengths of light which are characteristic of the excitation emissions of certain atoms such as sodium and copper. The light intensity at the selected wavelengths is sensed by a photomultiplier tube (30). In one embodiment, the interferometer (18) is a Fabry-Perot type interferometer and the separation of the plates (20 and 22) which form the Fabry-Perot etalon is controlled using a piezoelectric driver (26). A signal processor (34) correlates the sensed light emissions from the photomultiplier tube (30) with the selected wavelength that is determined by the piezoelectric driver (26). In another embodiment, the interferometer (40) is a narrow bandpass interferometric filter which is tiltable with respect to the collimated incident light from the processing chamber (10). Tilting a narrow bandpass interferometric filter (42) with respect to incident light changes the path length through the filter (42) and allows for the selective transmission of certain wavelengths of light. By rapidly tilting the narrow bandpass interferometric filter (42) at a rate between 5-300 Hz with respect to the incident light, a narrow range of wavelengths on the order of 3 nm can be scanned.
REFERENCES:
patent: 3740144 (1973-06-01), Walker
patent: 3914055 (1975-10-01), Wolga et al.
patent: 4005937 (1977-02-01), Barrett
patent: 4035643 (1977-07-01), Barrett
patent: 4092070 (1978-05-01), Smithline
patent: 4204771 (1980-05-01), Schull et al.
patent: 4448486 (1984-05-01), Evans
patent: 4454001 (1984-06-01), Sternhelm
patent: 4482248 (1984-11-01), Papuchon et al.
patent: 4525067 (1985-06-01), Hernandez
patent: 4602981 (1986-07-01), Chen et al.
patent: 4675072 (1987-06-01), Bennett et al.
patent: 4680084 (1987-07-01), Helmann et al.
patent: 4711573 (1987-12-01), Wijnges
patent: 4717446 (1988-01-01), Nagy
patent: 4732480 (1988-03-01), Fortunato et al.
patent: 4735507 (1988-04-01), Crane, Jr. et al.
patent: 4743114 (1988-05-01), Crane, Jr.
patent: 4758304 (1988-07-01), McNeil et al.
patent: 4838694 (1989-06-01), Betz et al.
patent: 4999013 (1991-03-01), Zoechbauer et al.
patent: 5059784 (1991-10-01), Northrup
Selwyn Gary S.
Walkup Robert E.
International Business Machines - Corporation
Turner Samuel A.
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