Externally induced voltage alterations for integrated circuit analysis

• US 6,580,281 B2
• Filed: 05/07/2001
• Issued: 06/17/2003
• Est. Priority Date: 02/22/2001
• Status: Active Grant

• Current Assignee: Quantum Focus Instruments Corporation
• Original Assignee: Optometrix, Inc.
• Inventors: Falk, Robert A.
• Primary Examiner(s): Nguyen, Vinh P.
• Application Number:
  US09/850,842
• Publication Number:
  US 20020163352A1
• Time in Patent Office: 771 Days
• Field of Search: 324/750, 324/751, 324/752, 324/765, 324/501, 250/310, 250/311, 438/14, 438/17-18
• US Class Current: 324/754.22
• 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 31/3163 Functional testing

Abstract

A method and circuit for integrated circuit analysis. The apparatus includes an irradiation component configured to irradiate an integrated circuit, a constant voltage source, one or more current chokes placed between the constant voltage source and one or more connections to the integrated circuit, and one or more voltage amplifiers. The irradiation component introduces changes in the electrical state of the integrated circuit. The one or more voltage amplifiers produces a state signal relating to the changes introduced by the irradiation component in the integrated circuit. The current choke separates the function, a DC function, of supplying a voltage bias to the integrated circuit from the function, an AC function, of signal generation. This allows separate optimization of the two functions—the ability to correctly bias the integrated circuit and obtain high signal-to-noise ratios for the resulting signal. This optimization improves the sensing abilities of the circuit.

Claims

1. A method for analyzing an integrated circuit, the method comprising:

irradiating the integrated circuit, thereby introducing changes in the electrical state of the integrated circuit;

providing a constant voltage source to the integrated circuit;

temporarily holding off changes in integrated circuit current flow, when the irradiating induces changes in the integrated circuit power requirements; and

producing a state signal relating to the changes introduced by irradiating in the integrated circuit.

2. The method of claim 1, wherein producing a state signal including filtering the changes induced by the modulated irradiation of the integrated circuit.

3. The method of claim 2, wherein producing a state signal including further includes amplifying the filtered changes induced by the modulated irradiation of the integrated circuit.

4. The method in claim 1, further comprising recording and displaying an image of the state signal as a function of scan position on the integrated circuit.

5. The method in claim 4, further comprising producing an image of the integrated circuit, said image being utilized to correlate the state signal to corresponding positions on the integrated circuit.

6. An apparatus for analyzing an integrated circuit, the apparatus comprising:

(a) a constant voltage source attached to an integrated circuit, said constant voltage source used to supply an operating voltage to said integrated circuit with said integrated circuit having been placed into an operating condition;

(b) a means for supplying modulated irradiation to the integrated circuit, said modulated irradiation changing the state of the integrated circuit;

(c) one or more current chokes placed between the voltage source and the integrated circuit, said current chokes producing a signal relating to the change in state induced by the modulated irradiation.

7. The apparatus in claim 6, further comprising one or more voltage amplifiers for amplifying the produced state signal.

8. The apparatus in claim 7, further comprising a means for focusing and scanning the irradiation over the integrated circuit, wherein the means for the scanning modulates the irradiation.

9. The apparatus in claim 8, wherein the irradiation is a laser source.

10. The apparatus in claim 8, wherein the irradiation is an electron beam.

11. The apparatus in claim 8, wherein the irradiation is an ion beam.

12. The apparatus in claim 6, further comprising a means for recording and displaying an image of the produced signal.

13. The apparatus in claim 12, further comprising a means for producing an image of the integrated circuit, said image being utilized to correlate the produced signal to corresponding positions on the integrated circuit.

14. The apparatus in claim 6, further comprising a means for filtering the signal.

15. The apparatus in claim 6, further comprising a means for temporarily bypassing the one or more chokes and allowing external changes in the integrated circuit'"'"'s state.

16. An apparatus for analyzing an integrated circuit, the apparatus comprising:

(a) a constant voltage source attached to an integrated circuit, said constant voltage source used to supply an operating voltage to said integrated circuit with said integrated circuit having been placed into an operating condition;

(b) a means for supplying modulated irradiation to the integrated circuit, said modulated irradiation changing the state of the integrated circuit;

(c) one or more current chokes placed between the voltage source and the integrated circuit, said current chokes producing a signal relating to the change in state induced by the modulated irradiation.

17. The apparatus of claim 16, further comprising a means for filtering the changes induced by the modulated irradiation of the integrated circuit.

18. The apparatus of claim 17, further comprising a means for amplifying the filtered changes induced by the modulated irradiation of the integrated circuit.

19. The apparatus in claim 16, further comprising a means for temporarily bypassing means for holding off changes in integrated circuit current flow.

20. The apparatus in claim 16, further comprising means for recording and displaying an image of the produced signal.

21. The apparatus in claim 20, further comprising a means for producing an image of the integrated circuit, said image being utilized to correlate the produced signal to corresponding positions on the integrated circuit.