FAILURE ANALYSIS METHOD AND FAILURE ANALYSIS APPARATUS

• US 20090002000A1
• Filed: 06/30/2008
• Published: 01/01/2009
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Nikawa, Kiyoshi
• Granted Patent: US 7,825,673 B2
• Time in Patent Office: Days
• US Class Current: 324/750.230
• CPC Class Codes: G01R 31/311 of integrated circuits G01R31/31728 takes precedence
• CPC Class Codes: G01R 31/315 by inductive methods

Abstract

Failure analysis method includes performing fixed radiation of semiconductor chip (wafer) by photocurrent generation laser beam, scanning and radiating a region to be observed on semiconductor chip by heating laser beam, detecting, by a SQUID fluxmeter, current change generated in the semiconductor chip by radiating the photocurrent generation laser beam and the heating laser beam, and analyzing failure of the semiconductor chip based on current change detected by the SQUID fluxmeter. Radiation of photocurrent generation laser beam and heating laser beam are performed from a back surface side of the LSI chip, and detection by the SQUID fluxmeter is performed on a front surface side of the LSI chip. In analysis of failure of the LSI chip, image processing is performed in which a signal outputted from the SQUID fluxmeter is made to correspond to a scanning point. Visualization of defects is possible.

Claims

1. A failure analysis method comprising:

performing fixed radiation of a semiconductor chip or wafer by a photocurrent generation laser beam;

scanning and radiating a region to be observed on said semiconductor chip or wafer by a heating laser beam;

detecting, by a magnetic sensor, current change generated in said semiconductor chip or wafer by radiating said photocurrent generation laser beam and said heating laser beam; and

analyzing a failure of said semiconductor chip or wafer based on said current change detected by said magnetic sensor.

2. The failure analysis method according to claim 1, wherein said magnetic sensor is a SQUID fluxmeter.

3. The failure analysis method according to claim 1, wherein, in said fixed radiation of said photocurrent generation laser beam, a p-n junction of said semiconductor chip or wafer is radiated.

4. The failure analysis method according to claim 1, wherein

said photocurrent generation laser beam permeates a substrate of said semiconductor chip or wafer and is in a wavelength region in which a photocurrent is generated at a p-n junction, and

said heating laser beam permeates a substrate of said semiconductor chip or wafer and is in a wavelength region in which wiring is heated without a photocurrent being generated at a p-n junction.

5. The failure analysis method according to claim 4, wherein

said photocurrent generation laser beam has a wavelength of 1.06 μ

m, and

said heating laser beam has a wavelength of 1.3 μ

m.

6. The failure analysis method according to claim 1, wherein

radiation of said photocurrent generation laser beam and said heating laser beam is performed from a back surface side of said semiconductor chip or wafer, and

detection by said magnetic sensor is performed at a front surface side of said semiconductor chip or wafer.

7. The failure analysis method according to claim 1, wherein

said magnetic sensor detects a magnetic field produced by current generated by said semiconductor chip or wafer, by radiation of said photocurrent generation laser beam and said heating laser beam.

8. The failure analysis method according to claim 1, wherein, in analysis of failure of said semiconductor chip or wafer, image processing is performed in which a signal outputted from said magnetic sensor is made to correspond (or mapped) to a scanning point.

9. The failure analysis method according to claim 1, wherein, in analysis of failure of said semiconductor chip or wafer, only a signal of a prescribed frequency in signals outputted from said magnetic sensor at a lock-in amplifier is extracted, and image processing is performed based on the extracted signal of a prescribed frequency.

10. A failure analysis apparatus comprising:

a heating laser which outputs a heating laser beam;

a photocurrent generation laser which outputs a photocurrent generation laser beam;

an optical system which outputs a mixed (or combined) laser beam, in which said photocurrent generation laser beam and said heating laser beam that have been inputted are mixed, towards a back surface of a sample formed of a semiconductor chip or wafer; and

a magnetic sensor which detects, at a front surface side of said sample, a magnetic field produced by a current generated by said sample by radiation of said mixed laser beam;

wherein

said optical system outputs position, based on a control signal, and performs fixed radiation onto a back surface of said sample, of said photocurrent generation laser beam of said mixed laser beam, and while scanning, based on a control signal, radiates onto the back surface of said sample said heating laser beam of said mixed laser beam.

11. The failure analysis apparatus according to claim 10, wherein

said magnetic sensor is a SQUID fluxmeter.

12. The failure analysis apparatus according to claim 10, comprising:

a lock-in amplifier which outputs an intensity signal obtained by extracting only a signal of a prescribed frequency, based on a magnetic field signal corresponding to a signal detected by said magnetic sensor.

13. The failure analysis apparatus according to claim 10, comprising:

a pulse generator which generates a modulation signal and a reference signal;

wherein

said heating laser outputs a heating laser beam to which modulation has been applied based on said modulation signal from said pulse generator, and

said lock-in amplifier outputs a phase signal based on said reference signal from said pulse generator.

14. The failure analysis apparatus according to claim 10, comprising:

a system-control system which generates an image display signal based on said phase signal and said intensity signal from said lock-in amplifier.

15. The failure analysis apparatus according to claim 10, wherein said magnetic sensor is a SQUID fluxmeter;

and

said apparatus further comprises;

a lock-in amplifier which outputs an intensity signal obtained by extracting only a signal of a prescribed frequency, based on a magnetic field signal corresponding to a signal detected by said magnetic sensor;

a pulse generator which generates a modulation signal and a reference signal;

wherein

said heating laser outputs a heating laser beam to which modulation has been applied based on said modulation signal from said pulse generator, and

said lock-in amplifier outputs a phase signal based on said reference signal from said pulse generator.