System and method for modulation mapping

• US 7,990,167 B2
• Filed: 07/31/2009
• Issued: 08/02/2011
• 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:
  US12/534,069
• Publication Number:
  US 20100039131A1
• Time in Patent Office: 732 Days
• Field of Search: 324/158.1, 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: 324/754.23
• 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 method for probing an integrated circuit (IC), comprising:

stimulating said IC with a test signal;

illuminating a selected area of said IC with a laser beam;

collecting beam reflection from said IC;

converting said beam reflection to an electrical probing signal;

selecting a frequency or a band of frequencies of said probing signal;

calculating at least one of a total amplitude, a total intensity, and a phase of said probing signal at the selected frequency or band of frequencies;

generating a spatial map of one of said total amplitude, total intensity, and phase, for various locations over a selected area of said IC; and

displaying the spatial map on a monitor.

2. The method of claim 1, further comprising providing a reference signal and wherein said calculating comprises multiplying said probing signal with the reference signal to thereby provide a product signal, and integrating said product signal.

3. The method of claim 2, wherein said reference signal is of frequency similar to that of said probing signal.

4. The method of claim 1, wherein said calculating comprises calculating total power at the selected frequency or band of frequencies, and said generating a spatial map comprises generating a spatial map of total power for various locations over the selected area of said IC.

5. The method of claim 1, wherein said illuminating comprises scanning the laser beam over a selected area of said IC.

6. The method of claim 1, wherein said collecting beam reflection further comprises converting beam reflection phase into beam reflection amplitude.

7. The method of claim 1, further comprising generating an optical image of said selected area of the IC.

8. The method of claim 5, wherein said collecting comprises collecting beam reflection from said scanning and further comprising generating an optical image of said selected area from said beam reflection.

9. The method of claim 1, wherein said calculating comprises calculating a total amplitude of said probing signal at the selected frequency or band of frequencies.

10. The method of claim 1, wherein said calculating comprises calculating a total intensity of said probing signal at the selected frequency or band of frequencies.

11. The method of claim 1, wherein said calculating comprises calculating a phase of said probing signal at the selected frequency or band of frequencies.

12. The method of claim 1, wherein selecting comprises using a spectrum analyzer to detect signal frequencies corresponding to the selected area.

13. A method for probing an integrated circuit (IC), comprising:

stimulating said IC with a test signal;

illuminating a selected area of said IC with a laser beam;

collecting beam reflection from said IC;

converting said beam reflection to an electrical probing signal;

selecting a frequency or a band of frequencies of said probing signal;

calculating at least one of a total amplitude, a total intensity, and a phase of said probing signal at the selected frequency or band of frequencies and comparing the results to a reference signal of a good IC.

14. A method for probing an integrated circuit (IC), comprising:

illuminating the IC with a light beam;

stimulating said IC with a test signal;

collecting beam reflection from said IC, wherein the beam reflection is modulated by the IC response to the test signal;

converting said beam reflection to an electrical probing signal;

detecting modulated beam reflection of said probing signal over a selected time period to obtain total modulation;

displaying said total modulation for a fixed position or various locations over a selected area of said IC.

15. The method of claim 14, wherein detecting modulated beam reflection comprises detecting changes in at least one of amplitude, intensity, power, polarization rotation, and phase of the beam reflection.

16. The method of claim 14, wherein obtaining total modulation comprises integrating changes in at least one of amplitude, intensity, power, polarization rotation, and phase of the beam reflection.

17. The method of claim 14, wherein collecting comprises passing the beam reflection through phase to amplitude converter.

18. The method of claim 14, further comprising providing a reference signal and multiplying said probing signal with the reference signal to thereby provide a product signal, and integrating said product signal.

19. The method of claim 14, wherein said total modulation comprises calculating total power at the selected frequency or band of frequencies, and said displaying comprises generating a spatial map of total power over selected area of said IC.

20. The method of claim 14, further comprising displaying an optical image of corresponding area of the IC.