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US5233203A Expired / Lapsed US ⏱️ 0.0 years remaining

Apparatus for detecting surface defects on a semiconductor wafer

Assignee: NEC Corp
•
Filing: 1992-02-10
•
Granted: 1993-08-03
•
Expires: 2012-02-10
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Abstract

Abstract An apparatus for detecting surface defects of a wafer includes a rotary unit rotatably attached to a vertical surface of a Z-X unit provided on a vertical surface of an L-shaped base and rotated with a vertically oriented semiconductor wafer held thereon by an attractive force of negative pressure created inside the rotary unit by evacuation of the air therein. An optical microscope is provided, which has its optical axis normal to the vertical surface of the wafer. The field of the microscope is moved smoothly along a radius direction of the wafer including the edge and the center of the wafer by the Z-X unit. At the same time, the wafer surface is illuminated by a spot laser beam, and blown by clean air ejected from a nozzle. The entire wafer surface is optically inspected by the optical microscope to receive reflected light which is detected by a photomultiplier for detecting deflects, such as particles, on the wafer surface.

Inventors

  • 👤 Sachiko Haga

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 11:30
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/9501; G01N21/9503; G01N21/94

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 81 words
An apparatus for detecting surface defects on a wafer, comprising: a rotary stage for holding a wafer such that a wafer surface is maintained vertically; a light emitter for illuminating said wafer surface; an optical microscope including an objective lens having an optical axis directed normal to said wafer surface maintained vertically, for receiving light reflected from said wafer surface; and a light sensor optically coupled to said objective lens so as to sense said light received from said wafer surface.
Claim 2
Independent Claim 81 words
An apparatus for detecting surface defects on a wafer, comprising: a rotary stage for holding a wafer such that a wafer surface is maintained vertically; a light emitter for illuminating said wafer surface; an optical microscope including an objective lens having an optical axis directed normal to said wafer surface maintained vertically, for receiving light reflected from said wafer surface; and a light sensor optically coupled to said objective lens so as to sense said light received from said wafer surface.
Claim 3
Dependent Claim 22 words
The apparatus as claimed in claim 1, further comprising a nozzle for ejecting clean air onto said wafer surface from one direction.
Claim 4
Dependent Claim 23 words
The apparatus according to claim 2, wherein said light emitter is a spot laser beam generator, and said light sensor is a photomultiplier.
Claim 5
Dependent Claim 43 words
The apparatus according to claim 3, wherein said rotary stage is rotatably supported on a Z-X stage which is supported on a vertical portion of a substantially L-shaped base, and said optical microscope is mounted on a horizontal portion of said L-shaped base
Claim 6
Dependent Claim 70 words
The apparatus according to claim 4, wherein said rotary stage is constructed in the form of a hollow cylinder with one end thereof closed by a wall formed with a plurality of suction holes and the other end in frictional contact with a vertical surface of said Z-X stage being, said rotary stage provided with an exhaust duct for extracting air trapped in an inner space of said hollow cylinder
Claim 7
Dependent Claim 23 words
The apparatus according to claim 5, wherein said rotary stage is rotated by a motor, and said Z-X stage is finely moved vertically.
Claim 8
Dependent Claim 31 words
The apparatus according to claim 6, wherein said nozzle is disposed above said rotary stage to eject clean air at an upper end of said rotary stage onto said wafer surface.
Claim 9
Dependent Claim 54 words
The apparatus according to claim 1, wherein said light sensor is a photomultiplier, and said optical microscope includes an eyepiece lens cylinder and a selecting means for selecting one of the photomultiplier and eyepiece lens cylinder and optically coupling a selected one of the photomultiplier and the eyepiece lens cylinder to said objective lens.

References Cited (Backward Citations)

JPS62127652A Cited
US4740708A Cited
US5127726A Cited
US4943732A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-08-02 1997-02-01 1997-08-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-08-02 2001-02-01 2001-08-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-08-02 2005-02-01 2005-08-03 $7700.00 Window Closed / Lapsed

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