Defect detection via acoustic analysis

• US 6,421,811 B1
• Filed: 09/30/1999
• Issued: 07/16/2002
• Est. Priority Date: 09/30/1999
• Status: Expired due to Fees

• Current Assignee: Advanced Micro Devices, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Goruganthu, Rama R., Bruce, Michael R., Birdsley, Jeffrey D., Davis, Brennan V., Ring, Rosalinda M.
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Kik, Phallaka
• Application Number:
  US09/409,498
• Time in Patent Office: 1,020 Days
• Field of Search: 716/1-21, 700/100-110, 702/54, 702/58-59, 702/103, 702/117-118, 324/512, 324/520, 324/537, 324/765
• US Class Current: 716/112
• CPC Class Codes: G01N 2291/012 Phase angle
• CPC Class Codes: G01N 2291/2698 Other discrete objects, e.g. bricks
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046
• 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 31/2898 Sample preparation, e.g. removing encapsulation, etching sample preparation in general G01N1/00
• CPC Class Codes: G01R 31/311 of integrated circuits G01R31/31728 takes precedence

Abstract

According to an example embodiment of the present invention, a defect detection approach involves detecting the existence of defects in an integrated circuit as a function of acoustic energy. Acoustic energy propagating through the device is detected. A parameter including information such as amplitude, frequency, phase, or a spectrum is developed from the detected energy and correlated to a particular defect in the device.

Claims

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

detecting acoustic energy propagation in the integrated circuit; and

detecting circuit defects as a function of the detected acoustic energy propagating in and current flowing in the integrated circuit.

2. A method for testing an integrated circuit, wherein the circuit has circuitry in a circuit side opposite a back side, the method comprising:

removing substrate from the back side and exposing a target region;

directing a laser at the target region, generating optical beam induced current (OBIC), and causing pn junction activity;

detecting acoustic energy propagation in the integrated circuit via at least one acoustic energy detector;

correlating the detected acoustic energy to a parameter; and

detecting at least one defect in the circuit as a function of the correlated parameter.

3. A method for testing an integrated circuit, according to claim 2, wherein directing a laser at the target region in the back side of the integrated circuit includes using a laser having a wavelength of about 1064 nanometers.

4. A method for testing an integrated circuit, according to claim 2, wherein directing a laser at the target region in the back side of the integrated circuit includes pulsing the laser.

5. A method for testing an integrated circuit, according to claim 4, further comprising maintaining pn junctions near their operating voltage.

6. A method for testing an integrated circuit, according to claim 2, wherein the laser is synchronized with said at least one detector, and wherein detecting at least one defect includes detecting a phase shift of the correlated detected acoustic energy.

7. A method for testing an integrated circuit, according to claim 2, wherein correlating the detected acoustic energy to a parameter includes using a computer arrangement.

8. A method for testing an integrated circuit, according to claim 2, wherein detecting at least one defect in the circuit as a function of the correlated parameter includes detecting at least one of:

an open circuit and a short circuit.

9. A method for testing an integrated circuit, according to claim 2, wherein detecting at least one defect in the circuit as a function of the correlated parameter includes comparing the correlated parameter to a standard parameter for a non-defective integrated circuit.

10. A method for testing an integrated circuit, according to claim 9, wherein detecting an acoustic energy propagation in the integrated circuit having a higher frequency and amplitude than the standard parameter indicates a short circuit.

11. A method for testing an integrated circuit, according to claim 9, wherein detecting an acoustic energy propagation in the integrated circuit having a lower frequency and amplitude than the standard parameter indicates an open circuit.

12. A method for testing an integrated circuit, according to claim 9, wherein removing substrate from the back side and exposing a target region includes removing an amount of substrate that corresponds to an amount of substrate removed from the non-defective integrated circuit when the standard parameter was ascertained.

13. A method for testing an integrated circuit, according to claim 2, wherein the integrated circuit is not powered.

14. A system for testing an integrated circuit having circuitry in a circuit side opposite a back side, the system comprising:

means for removing substrate from the back side;

a laser adapted to generate current in the integrated circuit;

means for detecting acoustic energy propagation in the integrated circuit;

means for correlating detected acoustic energy propagation to a parameter; and

means for detecting at least one defect in the circuit using the correlated parameter.

15. A system for testing an integrated circuit having circuitry in a circuit side opposite a back side the system comprising:

a substrate removal device;

a laser configured and arranged to excite circuitry in the integrated circuit;

at least one acoustic energy detector adapted to detect acoustic energy in said integrated circuit; and

a computer configured and arranged to correlate detected acoustic energy to a parameter that is used to detect at least one defect in the integrated circuit.

16. A system for testing an integrated circuit, according to claim 15, wherein the laser, said at least one acoustic energy detector, and the computer are communicatively coupled.

17. A system for testing an integrated circuit, according to claim 16, wherein the computer is configured and arranged to control the laser.

18. A system for testing an integrated circuit, according to claim 15, wherein the computer is further configured and arranged to detect at least one defect in the integrated circuit using the correlated detected acoustic energy.

19. A system for testing an integrated circuit, according to claim 18, wherein the computer is configured and arranged to detect at least one of:

a short circuit and an open circuit.