Process for imaging laserinterferometry and a laserinterferometer for carrying out said process
First Claim
1. A laserinterferometric process for examining a thin layer on a substrate comprising:
- radiating a specific surface of said thin layer to be examined by passing a laser beam over said specific surface;
deflecting said laser beam by an electrically modulated crystal onto said specific surface;
detecting the intensity of a reflected laser beam which is composed of a beam reflected from said specific surface and a beam reflected from the interface of said thin layer and said substrate;
evaluating said detected intensity in a data processing system; and
providing a readout of information concerning said layer to be examined.
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Abstract
The present invention relates to a laserinterferometric process, in particular, for use in etching thin layers, whereby a layer to be examined is radiated with a laser passing over a surface of the layer and the intensity of the reflected laser beam, which is composed of a beam reflected from the surface of the layer to be examined and one reflected from its lower interface is ascertained and evaluated by a data processing system from which the information concerning the layer to be examined is read out. The present invention also relates to an imaging laserinterferometer comprising a modulator, which deflects the laser beam, a detector for the reflected laser beam and a data processing systen, which analyzes the detector signals.
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Citations
21 Claims
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1. A laserinterferometric process for examining a thin layer on a substrate comprising:
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radiating a specific surface of said thin layer to be examined by passing a laser beam over said specific surface; deflecting said laser beam by an electrically modulated crystal onto said specific surface; detecting the intensity of a reflected laser beam which is composed of a beam reflected from said specific surface and a beam reflected from the interface of said thin layer and said substrate; evaluating said detected intensity in a data processing system; and providing a readout of information concerning said layer to be examined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A laserinterferometer for examination of a surface of a layer on a substrate comprising:
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laser means for producing a laser beam; modulator means including an electrically modulated crystal for deflecting said laser means on to said layer; detector means for detecting reflected laser beams and providing detector signals; and data processing means for analysis of said detector signals and providing a readout of information concerning said layer. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A laserinterferometric process for examining a thin layer on a substrate comprising:
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radiating a specific surface of said thin layer to be examined by passing a laser beam over said specific surface; modulating the intensity of said laser beam with a fixed frequency; detecting the intensity of a reflected laser beam in a narrow band about the modulating fixed frequency which is composed of a beam reflected from said specific surface and a beam reflected from the interface of said thin layer and said substrate; evaluating said detected intensity in a data processing system; and providing a readout of information concerning said layer to be examined. - View Dependent Claims (20, 21)
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Specification