IGBT module reliability evaluation method and device based on bonding wire degradation

Patent metadata

Field	Value
Publication number	US-11378613-B2
Application number	US-202117161684-A
Country	US
Kind code	B2
Filing date	Jan 29, 2021
Priority date	Jul 3, 2020
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

The disclosure discloses an IGBT module reliability evaluation method and device based on bonding wire degradation, which belong to the field of IGBT reliability evaluation. The realization of the method includes: obtaining a relationship between a IGBT chip conduction voltage drop Uces and an operating current Ic along with a chip junction temperature Tc; for an IGBT module under test, obtaining the conduction voltage drop Uces-c of the IGBT chip through the operating current Ic and the chip junction temperature Tc; obtaining an external conduction voltage drop Uces-m of the IGBT module by using a voltmeter; performing subtraction to obtain a voltage drop at a junction of a IGBT chip and a bonding wire, and combining the operating current to obtain a resistance at the junction; determining that the IGBT module has failed when the resistance at the junction increases to 5% of an equivalent impedance of the IGBT module.

First claim

What is claimed is:

1. An Insulate-Gate Bipolar Transistor (IGBT) module reliability evaluation method based on bonding wire degradation, wherein the method comprises the following steps:
(1) obtaining a relationship between a IGBT chip conduction voltage drop U ces and an operating current I c along with a chip junction temperature T c ;
(2) for an IGBT module under test, obtaining the chip conduction voltage drop U ces-c of the IGBT module under test through the operating current I c and the chip junction temperature T c based on the relationship between the IGBT chip conduction voltage drop U ces and the operating current I c along with the chip junction temperature T c ;
(3) obtaining an external conduction voltage drop U ces-m of the IGBT module under test;
(4) performing subtraction on the chip conduction voltage drop U ces-c and the external conduction voltage drop U ces-m of the IGBT module under test to obtain a voltage drop at a junction of a IGBT chip and a bonding wire, and combining the operating current to obtain a resistance at the junction;
(5) determining that the IGBT module under test has failed when the resistance at the junction increases to n % of an equivalent impedance of the IGBT module under test.

2. The method according to claim 1 , wherein step (1) comprises:
(1.1) selecting a non-aging IGBT module with the same model as the IGBT under test, changing a temperature at a position where the IGBT module is located, applying the operating current, and measuring a voltage between a collector and an emitter of the IGBT module, thereby obtaining the chip conduction voltage drop U ces of the IGBT module under corresponding conditions;
(1.2) recording data, and illustrating a three-dimensional diagram of the chip conduction voltage drop U ces of the IGBT module—the operating current I c —the chip junction temperature T c , and utilizing a curve fitting method to obtain a function U ces =f (I c , T c ) of U ces with respect to I c and T c .

3. The method according to claim 2 , wherein step (2) comprises:
(2.1) for the IGBT module under test, obtaining the chip junction temperature T c of the IGBT module under test when the IGBT module is a working state, and obtaining the operating current I c flowing through the IGBT module under test;
(2.2) based on the function of U ces with respect to I c and T c , performing calculation to obtain the chip conduction voltage U ces-c of the IGBT module under test in the working process.

4. The method according to claim 1 , wherein step (4) comprises:
obtaining the external conduction voltage drop U ces-m of the IGBT module under test, along with the chip conduction voltage drop U ces-c of the IGBT module under test obtained through calculation, obtaining the resistance R w at the junction of the chip and the bonding wire through a formula U ces-m =U ces-c +I c R w .

5. The method according to claim 2 , wherein step (4) comprises:
obtaining the external conduction voltage drop U ces-m of the IGBT module under test, along with the chip conduction voltage drop U ces-c of the IGBT module under test obtained through calculation, obtaining the resistance R w at the junction of the chip and the bonding wire through a formula U ces-m =U ces-c +I c R w .

6. The method according to claim 3 , wherein step (4) comprises:
obtaining the external conduction voltage drop U ces-m of the IGBT module under test, along with the chip conduction voltage drop U ces-c of the IGBT module under test obtained through calculation, obtaining the resistance R w at the junction of the chip and the bonding wire through a formula U ces-m =U ces-c +I c R w .

7. The method according to claim 4 , wherein step (5) comprises:
determining that the IGBT module under test has failed when the resistance at the junction increases to 5% of the equivalent impedance of the IGBT module under test.

8. The method according to claim 5 , wherein step (5) comprises:
determining that the IGBT module under test has failed when the resistance at the junction increases to 5% of the equivalent impedance of the IGBT module under test.

9. The method according to claim 6 , wherein step (5) comprises:
determining that the IGBT module under test has failed when the resistance at the junction increases to 5% of the equivalent impedance of the IGBT module under test.

10. An IGBT module reliability evaluation device based on bonding wire degradation, wherein the device comprises:
a relational expression obtaining module configured to obtain a relationship between a IGBT chip conduction voltage drop U ces and an operating current I c along with a chip junction temperature T c ;
a chip conduction voltage drop obtaining module configured to, for the IGBT module under test, obtain the chip conduction voltage drop U ces-c of the IGBT module under test through the operating current I c and the chip junction temperature T c based on the relationship between the IGBT chip conduction voltage drop U ces and the operating current I c along with the chip junction temperature T c ;
an external conduction voltage drop obtaining module configured to obtain an external conduction voltage drop U ces-m of the IGBT module under test;
a resistance obtaining module configured to perform subtraction on the chip conduction voltage drop U ces-c and the external conduction voltage drop U ces-m of the IGBT module under test to obtain a voltage drop at a junction of a IGBT chip and a bonding wire, and combine the operating current to obtain a resistance at the junction;
a failure determining module configured to determine that the IGBT module under test has failed when the resistance at the junction increases to n % of an equivalent impedance of the IGBT module under test.

11. The device according to claim 10 , wherein the relational expression obtaining module is configured to select a non-aging IGBT module with the same model as the IGBT under test, change a temperature at a position where the IGBT module is located, apply the operating current, and measure a voltage between a collector and an emitter of the IGBT module, thereby obtaining the chip conduction voltage drop U ces of the IGBT module under corresponding conditions, and record the data as well as illustrate a three-dimensional diagram of the chip conduction voltage drop U ces of the IGBT module—the operating current I c —the chip junction temperature T c , and utilize a curve fitting method to obtain a function U ces =f (I c , T c ) of U ces with respect to I c and T c .

12. The device according to claim 11 , wherein the chip conduction voltage drop obtaining module is configured to, for the IGBT module under test, obtain the chip junction temperature T c of the IGBT module under test when the IGBT module is a working state, and obtain the operating current I c flowing through the IGBT module under test, and calculate and obtain the chip conduction voltage U ces , of the IGBT module under test in a working process based on the function of U ces with respect to I c and T c .

13. The device according to any one of claim 10 , wherein the resistance obtaining module is configured to obtain the external conduction voltage drop U ces-m of the IGBT module under test, along with the chip conduction voltage drop U ces-c of the IGBT module under test obtained through calculation, and obtain the resistance R w at the junction of the chip and the bonding wire through a formula U ces-m =U ces-c +I c R w .

14. The device according to any one of claim 11 , wherein the resistance obtaining module is configured to obtain the external conduction voltage drop U ce

Assignees

• Univ Wuhan

Inventors

• He Yigang
• Li Lie
• He Liulu
• Wang Chenyuan

Classifications

• H10D12/411

  Insulated-gate bipolar transistors [IGBT] · CPC title

• G01R31/2642 Primary

  Testing semiconductor operation lifetime or reliability, e.g. by accelerated life tests · CPC title

• G01R31/261

  for measuring break-down voltage or punch through voltage therefor · CPC title

• G01R31/275

  for testing individual semiconductor components within integrated circuits · CPC title

• G01R31/2608

  for testing bipolar transistors · CPC title