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AssigneeInternational Business Machines Corporation
InventorsMurlidhar V. Kulkarni, William H. Lancaster, Jr.
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The invention is a method for detecting both surface topography and defect presence using an AC interferometer. Surface topography measurements are maximized by adjusting the signal voltage of the light modulator to a relative phase-sensitive value. Defect detection is maximized by adjusting the signal voltage of the light modulator to a relatively phase-insensitive value. This method not only allows for heretofore unknown defect detection by an AC interferometer but, because the signal voltage can be switched electronically, permits both observations to be taken at a high speed and for many points of a specimen, thereby making the method suitable for the manufacturing environment. More specifically, the method would be applicable to both optical disk and microchip manufacturing.
A method for making both dimensional measurements and defect detections on the surface of an object using a single interferometer, the interferometer including means for generating two discrete light beams incident upon different areas of the surface of the object and polarized in different directions, comprising:
A method for making both dimensional measurements and defect detections on an object using a single interferometer, the interferometer including means for generating two discrete light beams incident upon different areas of the surface of the object and polarized in different directions and a phase modulator having a voltage applied thereto which is determinative of the phase difference between the incident light beams, comprising:
An interferometric method for making both dimensional measurements and defect detections on an object, comprising:
Dependencies are inferred from the claim text.