The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 1996
Filed:
Aug. 26, 1994
Klaus J Bachmann, Raleigh, NC (US);
Nikolaus Dietz, Raleigh, NC (US);
Amy E Miller, Raleigh, NC (US);
North Carolina State University, Raleigh, NC (US);
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.