Optical apparatus for rapid defect analysis
First Claim
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1. Inspection apparatus for inspecting a surface of a sample, wherein said apparatus comprises:
- a wide scanning interferometer determining locations of surface defects;
a narrow scanning interferometer determining the profiles of said surface defects located by said wide scanning interferometer; and
means for establishing relative motion between said sample and said wide scanning and narrow scanning interferometers, with said surface adjacent to said wide scanning and narrow scanning interferometers.
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Abstract
Apparatus for inspecting the surface of a sample includes a wide scanning interferometer, which is used to locate defects, or anomalies in the surface, and a narrow scanning interferometer, which is used to develop profiles of individual defects found by the narrow scanning interferometer. The sample may be driven in rotation about an axis, while the interferometers are independently moved radially to the axis.
41 Citations
24 Claims
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1. Inspection apparatus for inspecting a surface of a sample, wherein said apparatus comprises:
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a wide scanning interferometer determining locations of surface defects; a narrow scanning interferometer determining the profiles of said surface defects located by said wide scanning interferometer; and means for establishing relative motion between said sample and said wide scanning and narrow scanning interferometers, with said surface adjacent to said wide scanning and narrow scanning interferometers. - View Dependent Claims (2, 4)
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3. Inspection apparatus for inspecting a surface of a sample, wherein said apparatus comprise:
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a wide scanning interferometer determining locations of surface defects; a narrow scanning interferometer determining the profiles of said surface defects located by said wide scanning interferometer; and means for establishing relative motion between said sample and said wide scanning and narrow scanning interferometers, with said surface adjacent to said wide scanning and narrow scanning interferometers, wherein said means for establishing relative motion includes first drive means for rotating said sample about an axis, second drive means for moving said wide scanning interferometer in a first direction extending radially away from said axis, and third drive means for moving said narrow scanning interferometer in a second direction extending radially away from said axis.
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5. The inspection apparatus of claim 5, wherein said interferogram is bright in areas corresponding to defects on said surface of said sample and dark in areas corresponding to flat portions of said surface of said sample.
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6. Inspection apparatus for inspecting a surface of a sample, wherein said apparatus comprises:
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a wide scanning interferometer determining locations of surface defects, wherein said wide-scanning interferometer is a common mode shearing type including a first laser light source, a first beamsplitter directing an illumination beam from said first laser light source in a first direction, a first Wollaston prism assembly breaking said illumination beam into a pair of sheared illumination sub-beams separated in a second direction, a first objective lens, through which through which said illumination sub-beams are directed to reflect from said surface of said sample, and through which return sub-beams reflected from said surface of said sample are transmitted back to said first Wollaston prism assembly, and a line scan sensor into which a return beam is projected from said first Wollaston prism assembly in a direction opposite said first direction, with an interferogram of said surface of said sample being formed on said line scan sensor, and with said line scan sensor providing, as an output, a first signal responsive to variations in said interferogram; a narrow scanning interferometer determining the profiles of said surface defects located by said wide scanning interferometer; and means for establishing relative motion between said sample and said wide scanning and narrow scanning interferometers, with said surface adjacent to said wide scanning and narrow scanning interferometers. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for inspecting a surface of a sample, wherein said method comprises:
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placing said sample on a turntable for rotation about an axis of rotation of said turntable with said surface of said sample being outwardly exposed from said turntable; moving a wide-scanning optical inspection device adjacent said surface of said sample in a first direction radial to said axis of rotation, with said wide-scanning optical device detecting defects within said surface as said sample is rotated by said turntable, and with a location of each defect detected by said wide-scanning optical device being stored in data storage means; moving a narrow-scanning optical inspection device adjacent said surface of said sample in a second direction radial to said axis of rotation among radial distances corresponding to each said location of each said defect previously detected by said wide-scanning optical device, with said narrow-scanning optical device providing signals representative of a surface profile of each said defect previously detected by said wide-scanning optical device as said sample is rotated by said turntable; and calculating said surface profile of each said defect within computing means from said signals representative of said surface profile. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification