Method and apparatus for inspecting high-precision patterns

• US 6,381,356 B1
• Filed: 10/20/1997
• Issued: 04/30/2002
• Est. Priority Date: 10/23/1996
• Status: Expired due to Term

• Current Assignee: Coltera LLC
• Original Assignee: NEC Corporation
• Inventors: Murakami, Shingo, Yamane, Tsuyoshi, Aida, Yoshiaki, Nakatani, Katsuhiko, Ogura, Yukio
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): CHAWAN, SHEELA C
• Application Number:
  US08/954,263
• Time in Patent Office: 1,653 Days
• Field of Search: 382/141, 382/143, 382/145, 382/147, 382/148, 382/149, 382/151, 382/184, 382/254, 382/255, 382/266, 356/239.2, 356/239.3, 356/237.3, 356/237.4, 356/237.6, 356/248.8, 430/5, 430/30
• US Class Current: 382/141
• 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 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14

Abstract

A device and method for inspecting a test piece with a laser beam in which the laser beam is divided into plural beams, and each of the plural beams has an identification marker, such as a particular polarity or intensity. Each of the marked beams, scans a different portion of the test piece to reduce the time needed to inspect the test piece.

Claims

1. A method of inspecting a surface of a test piece with a laser beam, comprising the steps of:

dividing the laser beam into a plurality of laser beams;

adding different features to respective divided laser beams for providing a different identification marker for each of said plurality of laser beams;

simultaneously scanning different portions of the surface of the test piece with responding independent laser beams having said different features;

forming an image of the surface of the test piece by using at least one of reflected and transmitted light for each of said plurality of marked laser beams, wherein said different identification marker comprises a different polarization state assigned to each of said plurality of marked laser beams.

2. A method of inspecting a surface of a test piece with a laser beam, comprising the steps of:

dividing the laser beam into a plurality of laser beams;

adding different features to respective divided laser beams for providing a different identification marker for each of said plurality of laser beams;

simultaneously scanning different portions of the surface of the test piece with responding independent laser beams having said different features;

forming an image of the surface of the test piece by using at least one of reflected and transmitted light for each of said plurality of marked laser beams, wherein said different identification marker comprises a variation in a light intensity assigned to each of said plurality of marked laser beams.

3. A method of inspecting a surface of a test piece with a laser beam, comprising the steps of:

dividing the laser beam into a plurality of laser beams;

adding different features to respective divided laser beams for providing a different identification marker for each of said plurality of laser beams;

simultaneously scanning different portions of the surface of the test piece with responding independent laser beams having said different features;

forming an image of the surface of the test piece by using at least one of reflected and transmitted light for each of said plurality of marked laser beams, wherein said laser beam has an ultraviolet wavelength.

4. An apparatus for inspecting a surface of a test piece with a laser beam, comprising:

a source of a laser beam;

a means for dividing said laser beam into a plurality of laser beams;

a means for adding different features to respective divided laser beams for assigning a plurality of identification markers;

a means for simultaneously scanning different portions of the surface of the test piece with responding independent laser beams having said different features, each of said plurality of marked laser beams simultaneously scanning a different portion of the surface of the test piece;

a means for detecting at least one of the light reflected from the surface of the test piece and the light transmitted through the surface of the test piece, wherein said detecting means detects light resulting from interaction of each of said plurality of marked laser beams with the surface of the test piece; and

an image processing unit for identifying each of said plurality of marked laser beams by said plurality of identification markers and for detecting a defect in the surface of the test piece by obtaining an image of the surface of the test piece from said detecting means, wherein each of said plurality of identification markers comprises a different polarization state assigned to each of said plurality of marked laser beams.

5. An apparatus for inspecting a surface of a test piece with a laser beam, comprising:

a source of a laser beam;

a means for dividing said laser beam into a plurality of laser beams;

a means for adding different features to respective divided laser beams for assigning a plurality of identification markers;

a means for simultaneously scanning different portions of the surface of the test piece with responding independent laser beams having said different features, each of said plurality of marked laser beams simultaneously scanning a different portion of the surface of the test piece;

a means for detecting at least one of the light reflected from the surface of the test piece and the light transmitted through the surface of the test piece, wherein said detecting means detects light resulting from interaction of each of said plurality of marked laser beams with the surface of the test piece; and

an image processing unit for identifying each of said plurality of marked laser beams by said plurality of identification markers and for detecting a defect in the surface of the test piece by obtaining an image of the surface of the test piece from said detecting means, wherein each of said plurality of identification markers comprises a variation in a light intensity assigned to each of said plurality of laser beams to form a plurality of marked laser beams.

6. The apparatus as claimed in claim 5, wherein said identification marker assigning means comprises an ultrasonic modulating means for analog modulation of each of said plurality of laser beams to change a light intensity thereof and a modulation signal generating means for outputting a modulation signal to said ultrasonic modulating means, said modulation signal controlling said light intensity of each of said plurality of marked laser beams in a time division manner.

7. An apparatus for inspecting a surface of a test piece with a laser beam, comprising:

a source of a laser beam;

a means for dividing said laser beam into a plurality of laser beams;

a means for adding different features to respective divided laser beams for assigning a plurality of identification markers;

a means for simultaneously scanning different portions of the surface of the test piece with responding independent laser beams having said different features, each of said plurality of marked laser beams simultaneously scanning a different portion of the surface of the test piece;

a means for detecting at least one of the light reflected from the surface of the test piece and the light transmitted through the surface of the test piece, wherein said detecting means detects light resulting from interaction of each of said plurality of marked laser beams with the surface of the test piece; and

an image processing unit for identifying each of said plurality of marked laser beams by said plurality of identification markers and for detecting a defect in the surface of the test piece by obtaining an image of the surface of the test piece from said detecting means, wherein the laser beam has an ultraviolet wavelength.