System and method for modulation mapping

• US 7,733,100 B2
• Filed: 05/18/2006
• Issued: 06/08/2010
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: DCG Systems Incorporated (Thermo Fisher Scientific Incorporated)
• Original Assignee: DCG Systems Incorporated (Thermo Fisher Scientific Incorporated)
• Inventors: Kasapi, Steven
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): Benitez; Joshua
• Application Number:
  US11/438,121
• Publication Number:
  US 20070046301A1
• Time in Patent Office: 1,482 Days
• Field of Search: 324750-753, 324/765, 250/338.4, 250/340, 250/341.2, 250/341.4, 250/341.8, 250/370.01, 250/492.2
• US Class Current: 324/754.22
• CPC Class Codes: G01R 31/2851 Testing of integrated circuits [IC] G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801
• CPC Class Codes: G01R 31/308 using non-ionising electromagnetic radiation, e.g. optical radiation investigating or analysing materials by the use of optical means G01N21/00; image analysis G06T7/00
• CPC Class Codes: G01R 31/311 of integrated circuits G01R31/31728 takes precedence

Abstract

An apparatus for providing modulation mapping is disclosed. The apparatus includes a laser source, a motion mechanism providing relative motion between the laser beam and the DUT, signal collection mechanism, which include a photodetector and appropriate electronics for collecting modulated laser light reflected from the DUT, and a display mechanism for displaying a spatial modulation map which consists of the collected modulated laser light over a selected time period and a selected area of the IC.

Claims

1. A system for testing an integrated circuit microchip using laser probing, comprising:

a laser source providing a laser beam;

a beam optics receiving said laser beam and focusing said laser beam onto a selected spot on said microchip;

a photosensor receiving reflected laser light that is reflected from said microchip and providing an electrical signal;

collection electronics receiving the electrical signal from said photosensor and providing an output signal;

an analysis system receiving said output signal over a specified period of time and providing a total power signal corresponding to the total radiation power received over the specified period of time.

2. The system of claim 1, wherein said analysis system comprises a selector, enabling selection of a frequency or a band of frequencies, and wherein said total power signal reflects total power at a selected frequency or a band of frequencies.

3. The system of claim 2, wherein said analysis system comprises a spectrum analyzer.

4. The system of claim 3, further comprising a scanner for scanning the laser beam and a frame grabber receiving said total power signal to thereby generate a spatial modulation map indicating total power value for various locations on said integrated circuit.

5. The system of claim 3, further comprising a digital signal processor receiving said total power signal.

6. The system of claim 3, wherein said analysis system further comprises an integrator integrating the output of the spectrum analyzer over a specified period of time.

7. The system of claim 1, wherein said analyzer is a lock-in amplifier.

8. The system of claim 7, further comprising a reference signal generator providing a reference signal, said reference signal having a frequency similar to that of said output signal, and having a different phase from that of said output signal.

9. The system of claim 8, further comprising a frame grabber receiving said total power signal.

10. The system of claim 8, further comprising a digital signal processor receiving said total power signal.

11. The system of claim 7, further comprising:

a scanner for scanning the laser beam;

a frame grabber receiving said total power signal; and

, a computer, said computer generating a spatial modulation map indicating total power value for various locations on said integrated circuit.

12. The system of claim 1, further comprising:

a scanner for scanning the laser beam;

a frame grabber receiving said total power signal; and

,

a computer, said computer generating a spatial modulation map indicating total power value for various locations on said integrated circuit.

13. The system of claim 1, wherein said beam optics further comprises phase to amplitude converter.

14. The system of claim 13, wherein said beam optics further comprises a beam scanner.

15. The system of claim 14, further comprising a computer, said computer generating a spatial modulation map indicating total power value for various locations on said integrated circuit.

16. The system of claim 15, wherein said phase to amplitude converter comprises a polarization differential probing (PDP) arrangement.

17. The system of claim 16, wherein said beam scanner comprises a laser scanning microscope (LSM).

18. The system of claim 16, further comprising a second photosensor receiving part of the reflected laser light.

19. The system of claim 15, further comprising a video amplifier.

20. The system of claim 1, wherein said analysis system further comprises an integrator integrating said output signal over a specified period of time to generate the total power signal.

21. The system of claim 1, wherein said beam optics comprises an objective lens and a solid immersion lens (SIL).

22. The system of claim 21, further comprising a scanning laser microscope (LSM) for scanning the laser beam.

23. The system of claim 21, wherein said beam optics further comprises:

a first beam splitter;

a Faraday Rotator following the first beam splitter;

a second beam splitter;

following the Faraday rotator; and

a variable retarder following the second beam splitter.

24. The system of claim 23, wherein said Faraday rotator is oriented to rotate the beam 45 degrees to generate a rotated beam, and the second beam splitter is oriented to transmit the rotated beam.

25. The system of claim 24, wherein said variable retarder is oriented to retard only one of a vertical or horizontal component of the rotated beam.

26. The system of claim 1, further comprising a scanning laser microscope (LSM) for scanning the laser beam.

27. The system of claim 1, wherein said collection electronics comprises an RF amplifier.

28. The system of claim 1, wherein said total radiation power comprises one of total radiation amplitude or total radiation intensity.

29. The system of claim 1, further comprising a scanner for scanning the laser beam over a selected area of the microchip to thereby generate a spatial map providing total power indication for each location on the selected area.