Optical coupling apparatus for a dual column charged particle beam tool for imaging and forming silicide in a localized manner

• US 7,612,321 B2
• Filed: 09/08/2005
• Issued: 11/03/2009
• Est. Priority Date: 10/12/2004
• Status: Active Grant

• Current Assignee: DCG Systems Incorporated (Thermo Fisher Scientific Incorporated)
• Original Assignee: DCG Systems Incorporated (Thermo Fisher Scientific Incorporated)
• Inventors: Tsao, Chun-Cheng
• Primary Examiner(s): Sohn; Seung C
• Application Number:
  US11/222,932
• Publication Number:
  US 20060076503A1
• Time in Patent Office: 1,517 Days
• Field of Search: 250/208.3, 250/227.26, 250/559.06, 250/396.R, 356/369, 356/193, 356/507
• US Class Current: 250/208.3
• CPC Class Codes: H01J 2237/2482 Optical means
• CPC Class Codes: H01J 2237/31749 Focused ion beam
• CPC Class Codes: H01J 37/228 whereby illumination and light collection take place in the same area of the discharge
• CPC Class Codes: H01J 37/3056 for microworking, e.g. etching of gratings, trimming of electrical components trimming of resistors H01C17/22
• CPC Class Codes: H01L 21/76892 modifying the pattern
• CPC Class Codes: H01L 21/76898 formed through a semiconductor substrate

Abstract

An optical coupling apparatus for a dual column charged particle beam tool allowing both optical imaging of an area of an integrated circuit, as well as localized heating of the integrated circuit to form silicide. In one embodiment, optical paths from a whitelight source and a laser source are coupled together by way of first and second beam splitters so that a single optical port of the dual column tool may be utilized for both imaging and heating. In another embodiment, a single laser source is employed to provide both illumination for standard microscopy-type imaging, as well as localized heating. In a third embodiment, a single laser source provides heating along with localized illumination for confocal scanning microscopy-type imaging.

Claims

1. An apparatus comprising:

a column charged particle beam tool;

a laser source;

a beam splitter optically coupled with the laser source;

a quarter-waveplate optically coupled with the laser source;

a photo-detector optically coupled with the beam splitter;

a frame grabber electrically coupled with the photo-detector;

at least one scan mirror optically coupled with the beam splitter;

a scanning lens optically coupled with the at least one scan mirror and an objective lens;

at least one beam scanner configured to move the at least one scan mirror to alter an optical path of light from the laser source through an optical port in the column of the column charged particle beam tool and scan the light over an area of a sample; and

a scanning controller electrically coupled with the at least one beam scanner, the scanning controller configured to control the movement of the at least one scan mirror via the at least one beam scanner.

2. The apparatus of claim 1, the at least one scan mirror comprising a horizontal scan mirror optically coupled with a vertical scan mirror.

3. The apparatus of claim 1, further comprising a scanning lens optically coupled with the at least one scan mirror and the objective lens.

4. The apparatus of claim 3, further comprising an alignment mirror optically coupled with the scanning lens and the objective lens.

5. The apparatus of claim 4, further comprising a spatial filter optically coupled with the beam splitter and the photo-detector.

6. The apparatus of claim 5, the spatial filter comprising:

a collimation lens optically coupled with a fiber and the beam splitter;

the fiber optically coupled with the laser source;

a focusing lens optically coupled with the beam splitter and the photo-detector; and

a pinhole structure optically coupled with the focusing lens and the photo-detector.

7. The apparatus of claim 1, wherein the photo-detector is a photodiode or a photo multiplier.

8. The apparatus of claim 1, wherein the beam scanner is a galvanometric scanner, an acousto-optic scanner, or a rotating polygon.

9. The apparatus of claim 1, further comprising:

a fiber coupling lens optically-coupled with the laser source;

a first end of an optical fiber optically coupled with the fiber coupling lens; and

a collimating lens optically coupled with a second end of the optical fiber and the beam splitter.

10. The apparatus of claim 1, wherein light from the laser source is adapted to image an area of an integrated circuit optically coupled with the charged particle beam tool.

11. The apparatus of claim 1, wherein light from the laser source is adapted to heat an area of an integrated circuit optically coupled with the charged particle beam tool.

12. An apparatus for inspecting a sample, comprising:

a dual column having a charged particle beam path and an optical path therein;

a laser source situated outside the dual column;

an optical coupling assembly coupling a laser beam from the laser source to the optical path;

an imager receiving reflections of the laser beam from the sample; and

a scanner operable in an imaging mode and in a static mode, whereby during the imaging mode the scanner scans the laser beam so as to image an area of the sample and during the static mode the scanner holds the laser beam statically over a particular location of the sample.

13. The apparatus of claim 12, wherein the scanner comprises one of galvanometric scanner, acousto-optic scanner or rotating polygon.

14. The apparatus of claim 12, wherein the scanner, the imager, and the optical coupling assembly form a confocal scanning microscope.

15. The apparatus of claim 12, wherein the imager forms a pixel-by-pixel image of the area of the sample via multiple scan lines.

16. The apparatus of claim 12, wherein the imager comprises a single element photo detector.