PATTERN DEFECT INSPECTION APPARATUS AND METHOD

• US 20080273193A1
• Filed: 05/01/2008
• Published: 11/06/2008
• Est. Priority Date: 05/02/2007
• Status: Active Grant

• Current Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: UTO, Sachio, NISHIYAMA, Hidetoshi, SHIMURA, Kei, NOGUCHI, Monori
• Granted Patent: US 7,746,453 B2
• Time in Patent Office: Days
• US Class Current: 356/73
• CPC Class Codes: G01N 2021/4711 Multiangle measurement
• CPC Class Codes: G01N 21/94 Investigating contamination, e.g. dust G01N21/85 takes precedence
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 21/95607 using a comparative method

Abstract

A pattern defect inspection apparatus capable of detecting minute defects on a sample with high sensitivity without generating speckle noise in signals is realized. Substantially the same region on a surface of a wafer is detected by using two detectors at mutually different timings. Output signals from the two detectors are summed and averaged to eliminate noise. Since a large number of rays of illumination light are not simultaneously irradiated to the same region on the wafer, a pattern defect inspection apparatus capable of suppressing noise resulting from interference of a large number of rays, eliminating noise owing to other causes and detecting with high sensitivity minute defects on the sample without the occurrence of speckle noise in the signal can be accomplished.

Claims

1. A defect inspection apparatus for inspecting a defect on a sample surface, comprising:

an illuminating unit for illuminating a plurality of regions on said sample surface;

an image forming unit for forming optical images of said plurality of regions of said sample surface illuminated by said illuminating unit;

a plurality of detecting units for detecting said optical images formed by said image forming unit and detecting reflected light from said sample surface; and

a defect detecting unit for processing said reflected light detected by said plurality of detecting units and detecting a defect on said sample surface.

2. A defect inspection apparatus according to claim 1, wherein substantially the same region on said sample surface is illuminated at mutually different timings, mutually different detectors detect reflected light from said same region at mutually different timings and the defect of said same region is detected on the basis of detection signals from said mutually different detectors.

3. A defect inspection apparatus according to claim 2, wherein said image forming unit branches an optical path for the rays of light condensed by a single objective lens and forms images by using a plurality of image forming lenses.

4. A defect inspection apparatus according to claim 2, wherein said plurality of regions illuminated by said illuminating unit are illuminated at mutually different angles of illumination.

5. A defect inspection apparatus for inspecting a defect on a sample surface, comprising:

a multi-direction illuminating unit for illuminating said sample surface from multiple directions among an azimuth of 360 degrees of said sample surface;

an imaging forming unit for forming an optical image of said sample surface illuminated by said multi-direction illuminating unit;

a plurality of detecting units for detecting the optical image formed by said imaging unit and detecting reflected light from said sample surface; and

a defect detecting unit for processing reflected light detected by said detecting units and detecting a defect on said sample surface.

6. A defect inspection apparatus according to claim 5, wherein substantially the same region on said sample surface is illuminated at mutually different timings, mutually different detectors detect reflected light from said same region at mutually different timings and the defect of said same region is detected on the basis of detection signals from said mutually different detectors.

7. A defect inspection apparatus according to claim 6, wherein said image forming unit branches an optical path for the rays of light condensed by a single objective lens and forms an image by using a plurality of image forming lenses.

8. A defect inspection method for inspecting a defect on a sample surface, comprising the steps of:

illuminating a plurality of regions on said sample surface;

forming optical images of said plurality of regions of said sample surface illuminated;

detecting said optical images formed and detecting reflected light from said sample surface; and

processing said reflected light detected and detecting a defect on said sample surface.

9. A defect inspection method according to claim 8, wherein substantially the same region on said sample surface is illuminated at mutually different timings, mutually different detectors detect reflected light from said same region at mutually different timings and the defect of said same region is detected on the basis of detection signals from said mutually different detectors.

10. A defect inspection method according to claim 9, wherein the optical image of said sample surface is formed by branching an optical path for the rays of light condensed by a single objective lens and forming an image by using a plurality of image forming lenses.

11. A defect inspection method according to claim 9, wherein said plurality of regions on said sample surface illuminated are illuminated at mutually different angles of illumination.

12. A defect inspection method for inspecting a defect on a sample surface, comprising the steps of:

illuminating said sample surface from multiple directions among an azimuth of 360 degrees of said sample surface;

forming an optical image of said sample surface illuminated from said multi-directions;

detecting the optical image formed and detecting reflected light from said sample surface; and

processing reflected light detected and detecting a defect on said sample surface.

13. A defect detection method according to claim 13, wherein substantially the same region on said sample surface is illuminated at mutually different timings, reflected light from said same region is detected at mutually different timings and the defect of said same region is detected on the basis of reflected light from said substantially the same region detected at mutually different timings.

14. A defect inspection method according to claim 13, wherein the optical image of said sample surface is formed by conducting optical path branching for the rays of light condensed by a single objective lens and also conducting image formation by using a plurality of image forming lenses.