System and method for modulation mapping

• US 9,239,357 B2
• Filed: 10/22/2012
• Issued: 01/19/2016
• 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): Valone, Thomas F
• Application Number:
  US13/657,666
• Publication Number:
  US 20130113510A1
• Time in Patent Office: 1,184 Days
• Field of Search: 324/752
• US Class Current: 1/1
• 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 laser probing system for testing an integrated circuit microchip having silicon substrate and plurality of semiconductor devices formed therein, comprising:

a microchip holder configured for supporting the microchip and enabling application of test signals to the microchip;

a laser source providing a laser beam;

beam optics configured for receiving said laser beam and, while the test signals are applied to the microchip, focusing said laser beam onto a selected area of the microchip that includes at least one semiconductor device;

a photosensor receiving modulated beam reflected from said selected area after being modulated by the semiconductor device in response to the test signals, and providing a corresponding electrical signal indicative of the semiconductor device'"'"'s response to the test signals;

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 generating modulation mapping corresponding to the selected area of the microchip.

2. The system of claim 1, wherein the beam optics is configured to focus said laser beam through the silicon substrate of said microchip.

3. The system of claim 1, wherein said analysis system comprises a spectrum analyzer.

4. 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.

5. The system of claim 1, wherein said analysis system comprises a lock-in amplifier.

6. The system of claim 5, 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.

7. The system of claim 6, further comprising a frame grabber.

8. The system of claim 1, further comprising a digital signal processor.

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

10. The system of claim 1, wherein said semiconductor device comprises a transistor having a gate, and wherein said beam optics further comprises a polarizer configured to polarize said laser beam in alignment with the gate of said transistor.

11. The system of claim 1, wherein said semiconductor device comprises MOS (metal-oxide-semiconductor) device.

12. The system of claim 1, further comprising a scanner for scanning the laser beam over a selected area of the microchip.

13. The system of claim 1, further comprising a display presenting the modulation mapping which corresponds to output signal over a selected time period and a selected area of the microchip.

14. The system of claim 10, wherein the polarizer is configured to polarize the laser beam such that the polarization is aligned parallel to length direction of the gate.

15. The system of claim 1, further comprising a video amplifier configured for receiving a DC part of the electrical signal output by the photosensor, and generating signal for a video image.

16. The system of claim 1, wherein said analysis system is configured to normalize the output signal and use the output signal to generate a normalized modulation mapping.

17. The system of claim 1, wherein said analysis system comprises a selector, enabling selection of a frequency or a band of frequencies, and the output signal corresponds to a selected frequency or a selected band of frequencies.