SiC Power Devices: Product Improvement Using Diffusion Soldering

Holz, Matthias; Hilsenbeck, J.; Otremba, Ralf; Heinrich, Alexander; Turkes, P.; Rupp, Roland

doi:10.4028/www.scientific.net/msf.615-617.613

Cited by 18 publications

(10 citation statements)

References 3 publications

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“…The team spent much time on the design of tooling and reflow profile for the vacuum reflow because it is one of our candidate solutions of high temperature resist alloys soldering for SiC power modules. After solving the void issue of solder joint, another problem namely die tilt was found, the same defect has been addressed in the paper of Holz et al [4], and is attributed to the surface energy of the solder drop. Figure 5 exhibited the die tilt issue discovered in this work, a thickness variation more than 70 m was found in the solder joint, and it seemed to be more acute than that pointed out in Infineon's report [4].…”

Section: Resultsmentioning

confidence: 93%

“…After solving the void issue of solder joint, another problem namely die tilt was found, the same defect has been addressed in the paper of Holz et al [4], and is attributed to the surface energy of the solder drop. Figure 5 exhibited the die tilt issue discovered in this work, a thickness variation more than 70 m was found in the solder joint, and it seemed to be more acute than that pointed out in Infineon's report [4]. After soldering, the flat Cu baseplate became a cry-shape with a severe warpage because the DBC and solder joints formed a thermal resistance on the top surface as cooling down and the unbalanced heat dissipation made the DBC and the Cu baseplate deform, which resulted in the thickness variation when the solder joints resolidified.…”

Section: Resultsmentioning

confidence: 93%

See 1 more Smart Citation

The first MIT 600 V/450 a IGBT module for EV/HEV applications

Kao

Leu

Chang

et al. 2013

2013 8th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)

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Nowadays, more than 180 countries including China, Japan, EU and others have signed the Kyoto Protocol, then "Energy-saving and Carbon reduction" becomes a popular slogan and an important mission to protect the environment and to pursue the national sustainability. Taiwan government is making many environmental policies as well for driving the people to purchase the eco-products like electric car, hybrid car and household appliances to reach the goal of Carbon reduction, and the industries are also actively involved in the mass production of the key components such as high power IGBT modules for EV / HEV, intelligent power module (IPM) for air-conditioner, and MOSFET SiP modules for the power management of consumer electronics and hand-held machine tools. The first 600 V / 450 A IGBT module for EV / HEV application developed by ITRI was announced in this work. The module was composed of IGBTs and freewheel diodes (FWD), firstly 2 IGBTs and 2 FWDs were attached on one Al2O3 direct bonded copper (DBC) substrate by a Pb-free solder perform with a thickness of 100 m in a vacuum reflow oven, and 3 DBCs were then soldered on a Cu baseplate by a solder perform as well. After cleaning, a heavy Al wire was used to connect the devices and DBCs, and subsequently the housing was adhered to the Cu baseplate by an adhesive. Finally, a Si gel with a dielectric strength higher than 10 kV / mm was poured for insulation and then agglutinated by heating. The process conditions were optimized in this study, a die shear strength higher than 20 MPa was acquired after optimizing the reflow profile, and a design of experiments (DoEs) plan was executed to obtain a pull strength higher than 800 g for the heavy Al wire bonding. After temperature cycling for 1000 times, the loss of the strengths was less than 20%, and the long-term reliability of the power module was verified

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 93%

The first MIT 600 V/450 a IGBT module for EV/HEV applications

Kao

Leu

Chang

et al. 2013

2013 8th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)

View full text Add to dashboard Cite

show abstract

“…Currently, small chip size of SiC devices ranging up to a few mm2 are only available on the mass production level in the market because of high crystal defects in SiC substrate. There are some researches how to utilize such small chips [6]. In order to compose large rating current power module, one solution is to place many small SiC chips parallel.…”

Section: A High-density Packagingmentioning

confidence: 99%

Ultra compact, low thermal impedance and high reliability module structure with SiC Schottky Barrier Diodes

Ikeda

Nashida

Horio

et al. 2011

2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

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An advanced module structure for taking advantage of superior characteristics of Silicon Carbide (SiC) device was researched and developed. This structure can realize about four times of power rating density and one half of thermal impedance compared to that of conventional structure. Also, this structure achieved to have higher reliability by applying epoxy molding structure and copper pin connection to conduct current to/from power chips instead of aluminum bonding wire.

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“…Figure 3 demonstrated another problem that often found in the assembly process, the tilt of the IGBT chip after soldering. It was attributed to the inherent surface energy of Pb-free solder material [7] and the deformation of the baseplate after reflow, and potentially results in the yield loss and reliability issues under power cycling and temperature cycling tests. The thermal stress induced by the mismatch of thermal expansion coefficients concentrated at the thinner solder layer, and it may speed up the failure after thousands of power cycling.…”

Section: Issues Of Pb-free Soldering In Embedded Power Modulesmentioning

confidence: 99%

Dual-phase solid-liquid interdiffusion bonding, a solution for the die attachment of WBG

Chang

Chuang

et al. 2012

2012 14th International Conference on Electronic Materials and Packaging (EMAP)

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Wide band gap (WBG) semiconductors such as SiC and GaN devices are expected to replace Si power devices in the next generation power modules for renewable energy and smart grid to enhance their energy conversion efficiency through a characteristic of high frequency switching. However, the temperature of the WBG power module may reach 250 C as operating, which is much higher than the melting temperatures of the conventional solder materials like Sn37Pb (187 C), Sn3.0Ag0.5Cu (217 C) and Sn0.7Cu (227 C). Therefore, a new die attaching method is an urgent research subject for the assembly of WBG power modules. Sandia National Laboratories won the R&D 100 award in 2009 by the world's first full SiC module, in which the die attaching of SiC devices was accomplished by a transition liquid phase (TLP) method, 2 intermetallic phases including Ag 3 Sn and Ni 3 Sn 4 were formed to bond SiC devices on a direct bond aluminum (DBA) and mount the DBA on a metal matrix composite baseplate, respectively, and the power module was capable to operate under a condition in excess of 400 C. Subsequently, Infineon announced a power chip embedded technology named BLADE for renewable energy applications in 2011, a same process so-called diffusion soldering was used to attach Si MOSFET device on an organic carrier by producing an intermetallic layer like Cu 6 Sn 5 between them. However, some disadvantages have been found in the previous cases. First, the bonding time is too long to achieve a high throughput production when the process temperature is lower than 300 C, whatever, the power ICs are easily damaged when the process temperature is as high as 350 C. Second, the intermetallic joint might degrade due to the voids induced by a volume contraction as heated. Third, there are some defects such as Kirkendall voids are formed at the interface between different intermetallics, which significantly impacts the reliability performance of the joint. A dual-phase solid-liquid interdiffusion bonding process was developed to solve the above-mentioned issues in this study. By the elemental design of the electrode compositions on both chip and substrate, a dual-phase intermetallic joint was formed to attach the chip on the substrate, and the bonding temperature was decreased to just 260 C. Furthermore, almost no void was found within the joint because they were rapidly stuffed by the formation of secondary intermetallic. The shear strength of the intermetallic joint was measured being higher than 20 MPa, even though experienced a temperature cycling test (Condition B, JESD22-A104), meaning that the new bonding technology was reliable and capable of manufacturing WBG power modules.

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SiC Power Devices: Product Improvement Using Diffusion Soldering

Cited by 18 publications

References 3 publications

The first MIT 600 V/450 a IGBT module for EV/HEV applications

The first MIT 600 V/450 a IGBT module for EV/HEV applications

Ultra compact, low thermal impedance and high reliability module structure with SiC Schottky Barrier Diodes

Dual-phase solid-liquid interdiffusion bonding, a solution for the die attachment of WBG

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