Light beam apparatus and method for orthogonal alignment of specimen

• US 7,327,452 B2
• Filed: 08/09/2004
• Issued: 02/05/2008
• Est. Priority Date: 08/09/2004
• Status: Active Grant

• Current Assignee: DCG Systems Incorporated (Thermo Fisher Scientific Incorporated)
• Original Assignee: Credence Systems Corporation (COHU Incorporated)
• Inventors: Frank, Jonathan, Cotton, Daniel
• Primary Examiner(s): Toatley, Jr.; Gregory J.
• Assistant Examiner(s): Skovholt; Jonathan
• Application Number:
  US10/912,896
• Publication Number:
  US 20060028641A1
• Time in Patent Office: 1,275 Days
• Field of Search: None
• US Class Current: 356/244
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G02B 21/26 Stages; Adjusting means therefor

Abstract

A system for orthogonal alignment of a specimen disclosed. The system includes a light-beam illumination source, collection optics, imaging optics, and a tiltable specimen holder. The light-beam source is activated to illuminate a spot on the specimen, and the imaging optics is used image that spot. The location of the spot on the imager is used to determine whether the specimen is orthogonal to the optical axis of the collection optics.

Claims

1. A system for orthogonal alignment of a specimen to an optical axis of an optical system, comprising:

a tiltable test bench for placing the specimen thereupon;

a plurality of lifters coupled to said tiltable test bench and operable to control the leveling of said tiltable test bench;

optical elements defining an optical path axis, said optical elements comprise a solid immersion lens;

a light-beam source for illuminating said specimen through said optical elements; and

,

an imager for imaging said light-beam after reflection from said specimen to thereby provide an indication of leveling position of said tiltable test bench.

2. The system of claim 1, further comprising manual adjustment knobs coupled to said lifters.

3. The system of claim 1, further comprising a plurality of electrical motors each connected to a respective one of said lurality of lifters.

4. The system of claim 3, further comprising a controller coupled to each of said electrical motors.

5. The system of claim 4, further comprising a feedback loop providing a signal from said imager to said controller.

6. The system of claim 1, wherein said light-beam source comprises a laser.

7. The system of claim 2, wherein said light-beam source comprises a laser.

8. The system of claim 3, wherein said light-beam source comprises a laser.

9. The system of claim 1, further comprising a laser scanning microscope (LSM).

10. An integrated system for testing an integrated cfrcuit (IC), comprising:

a tiltable holder for mounting the IC thereto;

collection optics comprising a solid immersion lens and a laser scanning microscope (LSM);

a primary illumination source for illuminating said IC through said collection optics in a navigation mode;

a light-beam source for illuminating a spot on said IC;

an imager for imaging said IC using light from said primary source and for imaging said spot on said IC; and

a photon sensor operable in a detection mode to detect photons emmitted from the IC and generate corresponding electrical signals.

11. A method for leveling a specimen with respect to an optical system having collection optics and an imager, comprising:

placing said specimen on a tiltable holder;

operating the imager to image a spot on the specimen through a solid immersions lens;

noting the imaged location of said spot as reflected onto said imager;

comparing said imaged location to a reference location; and

if said imaged location differs from said reference location, tilting said tiltable holder so that the imaged location matches the reference location.

12. A system for alignment of a specimen to an optical axis of an optical system, comprising:

a tiltable holder bench for placing the specimen thereupon;

a plurality of lifters coupled to said tiltable holder bench and operable to control the leveling of said tiltable holder bench;

optical elements defining an optical path axis, wherein said optical elements comprise a solid immersion lens;

a light-beam source for illuminating said specimen through said optical elements; and

,

an imager for imaging said light-beam after reflection from said specimen to thereby provide an indication of leveling position of said tiltable holder bench.

13. The system of claim 12, further comprising a processor detecting intensity level of the reflection and controlling the tiltable holder to assume a position resulting in highest intensity.

14. The system of claim 12, further comprising a plurality of electrical motors each connected to a respective one of said plurality of lifters.

15. A method for maximizing light collection efficiency in emission testing of a specimen comprising:

placing a specimen on a tiltable holder bench;

illuminating the specimen with a light beam at a defined spot;

measuring intensity of light reflected from the defined spot on the specimen; and

slanting the tiltable holder bench and specimen while maintaining the illumination at the defined spot until a position is found resulting in the maximum intensity of light reflected from the defined spot.

16. The method of claim 15, wherein the measured intensity is compared to the light beam intensity.

17. The method of claim 15, wherein the light beam is a laser beam.

18. The method of claim 15, wherein the slanting is performed by providing a feedback signal to the tiltable holder bench.

19. The method of claim 18, wherein providing the feedback signal further comprises electronically slanting the tiltable holder bench in response to the measured intensity.

20. The method of claim 15, further comprising placing a solid immersion lens on the specimen.

21. A system for maximizing light collection efficiency in emission testing of a specimen. comprising:

a tiltable holder bench for placing a specimen thereon;

a series of optical elements defining an optical path axis;

a light beam source for illuminating the specimen through the series of optical elements;

an imager for imaging a light emission intensity;

a controller for measuring intensity of light beam reflection from the specimen and comparing it to a reference intensity;

wherein if the measured intensity is less than the reference intensity, the controller causes the tiltable holder bench to assume another tilt orientation with respect to the optical elements.

22. The system of claim 21, wherein the specimen is an integrated circuit.

23. The system of claim 22, wherein the light beam source is a laser.

24. The system of claim 23, further comprising an imager to detect the light reflected from the specimen.

25. The system of claim 24, further comprising a tilting controller to electronically tilt the tiltable holder bench in response to a comparison by the controller of the light intensity and the reference intensity.

26. system of claim 25, further comprising a feedback loop providing a signal from the controller to the tiltable holder bench.

27. The system of claim 21, wherein the optical elements further comprise a solid immersion lens.