Reliability of thick Al wire bonds in IGBT modules for traction motor drives

Onuki, Jin; Koizumi, Masahiro; Suwa, Masaki

doi:10.1109/6040.826768

Cited by 81 publications

(24 citation statements)

References 6 publications

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“…1,2) In order to make high voltage, high current IGBT's, modules with high reliability on which many chips can be assembled in parallel must be developed. 3) As previously reported, 3) one side of the chip is soldered to a common electrode, and the other side of the chip is connected to another common electrode by ultrasonic, thick Al wire bonding technology. A metal substrate and AlN are used for heat dissipation and insulation, respectively.…”

Section: Introductionmentioning

confidence: 99%

Influence of Soldering Conditions on Void Formation in Large-area Solder Joints

et al. 2002

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This paper aims to clarify the process factors for applying the void free soldering process to practical use. Solder cleanliness lessens the influence of the heating rate on the void formation during soldering. The lowest vacuum for the purpose of void free soldering for cleaning and Ag coating, and for soldering were 2 × 10 −3 Pa and 4 × 10 −1 Pa, respectively. Cooling in N 2 lessens the void formation during soldering. The allowable standing time from the Ag coating to soldering is 25 h. The reliability of power modules made with this new process was satisfactory. (Received February 28, 2002; Accepted May 30, 2002) Keywords: void free soldering, silver film, vacuum of the chamber, vacuum of the soldering furnace, cooling in N 2 , reliability

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Section: Introductionmentioning

confidence: 99%

Influence of Soldering Conditions on Void Formation in Large-area Solder Joints

et al. 2002

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“…Onuki et al have reported that such fatigue cracking would be suppressed when cyclic temperature fluctuation during operations is kept lower than 40 K. 1) They show that fatigue cracking occurs inside a bonded Al wire, not along the bonding interface. They also show that bonding strength depends on the film quality and increases with decrease of Al film hardness.…”

Section: Introductionmentioning

confidence: 99%

“…1) A SEM micrograph of Al wire bonds and an Al-1 mass% Si electrode film around wire bonds of the IGBT chip after the operation of invertors is shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

“…For this, one side of a chip should be connected to a common electrode by soldering processes, and the other Al-1 mass%Si film electrode side of the chip should be connected to another common electrode by an ultrasonic thick Al wire bonding technology. 1) In usual, thick 6-8 mm Al-1 mass% Si films were deposited on an IGBT chip by sputtering process for thick Al wire bonding capability and for large current application.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Texture and Grain Size on the Deformation Behavior of Sputtered Thick Al-Si Films during Cyclic Heating and Cooling

et al. 2011

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Thick (8 mm) Al-Si films both on poly Si (0.5 mm thick)/SiO 2 /Si and SiO 2 /Si substrates were subjected to cyclic current application or cyclic heating and cooling. Both the cyclic current application and the cyclic heating and cooling led to specimen surface roughening. The average roughness increased with the number of cycles, but the extent of roughness for the former was much larger than that for the latter. These results correspond to the fact that grain size and texture for the latter are two times larger and more [111] oriented than those for the former, respectively. According to Electron Back Scattering Pattern (EBSP) measurements, grains with an orientation deviating from [111] were found to deform heavily during the cyclic current charging or heating, resulting in grain extrusion on the surface.

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“…35) As modules are composed of different materials with different thermal expansion coefficients, thermal stresses are induced at solder and wire bond joints. 1,4,5) The reliability enhancement of Al wire bonds is especially crucial to raise the reliability of IGBT modules at high temperatures because breaks in the Al wire itself can occur 1,68) through crack propagation along the small grain boundaries near the bonding interface due to tensile thermal stress generated during the operating cooling process 25) in the modules as schematically shown in Fig. 2.…”

Section: Introductionmentioning

confidence: 99%

Reliability Enhancement of Thick Al–Cu Wire Bonds in IGBT Modules Using Al<sub>2</sub>Cu Precipitates

et al. 2012

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The reliability enhancement of Al wire bonds used in the insulated gate bipolar transistor (IGBT) modules is crucial to raise their reliability at the high operating temperatures of the motor vehicles in which the modules are widely used because cracking can occur in the Al. We investigated the bonding reliability of thick Al0.5 mass% Cu wires, inside of which very fine Al 2 Cu phases precipitated in both grain boundaries and the Al matrix. We found the reliability of the aged AlCu wire bonds was much better than the reliabilities for AlCu wire bonds without aging and conventional AlNi wire bonds for temperature change ¦T of 50 K. We also found from thermal cycle test results that Al 2 Cu precipitates prevented crack propagation due to thermal expansion mismatch between Al wires and Si substrate.

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Reliability of thick Al wire bonds in IGBT modules for traction motor drives

Cited by 81 publications

References 6 publications

Influence of Soldering Conditions on Void Formation in Large-area Solder Joints

Influence of Soldering Conditions on Void Formation in Large-area Solder Joints

Effect of Texture and Grain Size on the Deformation Behavior of Sputtered Thick Al-Si Films during Cyclic Heating and Cooling

Reliability Enhancement of Thick Al–Cu Wire Bonds in IGBT Modules Using Al<sub>2</sub>Cu Precipitates

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Reliability of thick Al wire bonds in IGBT modules for traction motor drives

Cited by 81 publications

References 6 publications

Influence of Soldering Conditions on Void Formation in Large-area Solder Joints

Influence of Soldering Conditions on Void Formation in Large-area Solder Joints

Effect of Texture and Grain Size on the Deformation Behavior of Sputtered Thick Al-Si Films during Cyclic Heating and Cooling

Reliability Enhancement of Thick Al&ndash;Cu Wire Bonds in IGBT Modules Using Al<sub>2</sub>Cu Precipitates

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Reliability Enhancement of Thick Al–Cu Wire Bonds in IGBT Modules Using Al<sub>2</sub>Cu Precipitates