Wire Bond Failures in Power Modules

Author(s):  
S. Ramminger ◽  
G. Wachutka

Power modules are key components for traction applications, railway locomotives, streetcars and elevators, all of which are equipped with Insulated Gate Bipolar Transistor (IGBT) modules. In this application field, a highly reliable system is of uppermost interest. Reliability tests show that wire bonding and soldering may cause the modules to fail. The packaging setup is a multilayer system in which different materials are soldered together. During a temperature swing caused by self-heating and/or by changes in the ambient temperature, the layers expand differently. This generally causes shear forces at the terminations of joint interfaces finally leading to material fatigue and shorter life. In this paper, we give an overview of the wire bonding technique used in power modules and discuss the mechanisms and failure modes associated with it.

Author(s):  
Erick Gutierrez ◽  
Kevin Lin ◽  
Douglas DeVoto ◽  
Patrick McCluskey

Abstract Insulated gate bipolar transistor (IGBT) power modules are devices commonly used for high-power applications. Operation and environmental stresses can cause these power modules to progressively degrade over time, potentially leading to catastrophic failure of the device. This degradation process may cause some early performance symptoms related to the state of health of the power module, making it possible to detect reliability degradation of the IGBT module. Testing can be used to accelerate this process, permitting a rapid determination of whether specific declines in device reliability can be characterized. In this study, thermal cycling was conducted on multiple power modules simultaneously in order to assess the effect of thermal cycling on the degradation of the power module. In-situ monitoring of temperature was performed from inside each power module using high temperature thermocouples. Device imaging and characterization were performed along with temperature data analysis, to assess failure modes and mechanisms within the power modules. While the experiment aimed to assess the potential damage effects of thermal cycling on the die attach, results indicated that wire bond degradation was the life-limiting failure mechanism.


2013 ◽  
Vol 66 (4) ◽  
pp. 431-438
Author(s):  
Augusto Ottoni Bueno da Silva ◽  
Newton de Oliveira Pinto Júnior ◽  
João Alberto Venegas Requena

The aim of this study was to evaluate through analytical calculation, two-dimensional elastic modeling, and three-dimensional plastic modeling, the bearing capacity and failure modes of composite hollow trusses bi-supported with a 15 meter span, varying the number of central Vierendeel panels. The study found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer supports the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels.


Author(s):  
Wenzhao Liu ◽  
Dao Zhou ◽  
Francesco Iannuzzo ◽  
Michael Hartmann ◽  
Frede Blaabjerg

2012 ◽  
Vol 2012 (1) ◽  
pp. 000209-000214 ◽  
Author(s):  
M. Schneider-Ramelow ◽  
J.-M. Göhre ◽  
U. Geißler ◽  
S. Schmitz ◽  
K.-D. Lang

Asian industry and development is currently very focused on replacing extremely expensive Au wire with Cu or Pd-plated Cu in IC (mass production) packaging technologies (ball/wedge bonding). In contrast, Europe traditionally is researching and developing in the field of wedge/wedge bonding using heavy wire (> 100 μm) for power electronic modules or standard (thin) wire (< 100 μm, mostly 25–50 μm) for chip-on-board (COB) applications. One primary failure mechanism limiting the lifetime of power modules is Al wedge lift-off due to the different coefficients of thermal expansion (CTE) of the Al wedge and the chip (Si). This classical type of fatigue cracking can be reduced by using materials of higher strength and/or lower CTE. Key strategies include doping or alloying elements and/or optimizing bonding conditions to improve the microstructure. Cu-based wire or Cu-Al bimetal ribbons are another option, although these include changes to the chip structure and metallization. AlSi1 has been the industry standard bonding material in wedge/wedge thin wire bonding for many years. Its thermal stability is limited at temperature above ≈100°C due to recrystallization, grain growth and Si coagulation. For example, glob top material curing processes used in chip on board (COB) applications (e.g. several hours at 160°C) can decrease the strength of standard AlSi1 wire to less than 60% of its original value. Research and development is currently attempting to improve this situation by alloying and doping Al base material to increase high-temperature behavior or by using Al-coated Au or Cu wires. The presentation will give an overview of alternative wedge/wedge wire bonding materials and discuss the challenges to processing and reliability.


2018 ◽  
Vol 250 ◽  
pp. 03003
Author(s):  
Noor Suhaida Galip ◽  
Roslli Noor Mohamed ◽  
Ramli Abdullah

The bent-up bars have not been used as shear reinforcement in beams since the past 40 years or so. In all cases of design and construction nowadays, shear forces are resisted by vertical links only. Some complications in installing the multiple set of bent-up bars, the less opportunity to have sufficient number of bent-up bars due to small number of flexural reinforcement provided at the mid-span of the beams and also the large anchorage required for the horizontal portion of the bars beyond the upper end of the bend could be the reasons behind this. This paper presents the results of tests on five rectangular reinforced concrete beams in which the effectiveness of welded inclined bars (WIB) as shear reinforcement was studied. Two of the beams were controlled specimens, with no shear reinforcement in one, and full design vertical links in another. The other three beams were provided with three different quantities of WIB, measured in terms of area to distance ratio, Asw / S as shear reinforcement in the shear spans. All beams were tested to failure under two point loads with a shear span to effective depth ratio of 2.34, which would ensure that the failure was due to shear unless their shear capacities were larger than the flexural capacity. The performances of the beams were measured in terms of deflection, crack formation, strains in WIB and on the concrete surfaces in the shear region, ultimate loads and failure modes. The results show that WIB alone is capable of carrying the whole shear forces in the beam, and larger shear capacities are achieved with a larger quantity of WIB, and a higher grade of the bars used. The beam with WIB requires 22% less in the quantity of Asw / S compared to that with vertical links to achieve the same shear resistance. These suggest that WIB can be used as an effective system of shear reinforcement in beams.


Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 620 ◽  
Author(s):  
Bernardo Cougo ◽  
Lenin Morais ◽  
Gilles Segond ◽  
Raphael Riva ◽  
Hoan Tran Duc

This paper presents the influence of different pulse width modulation (PWM) methods on losses and thermal stresses in SiC power modules used in a three-phase inverter. The variation of PWM methods directly impacts instantaneous losses on these semiconductors, consequently resulting in junction temperature swing at the fundamental frequency of the converter’s output current. This thermal cycling can significantly reduce the lifetime of these components. In order to determine semiconductor losses, one needs to characterize SiC devices to calculate the instantaneous power. The characterization methodology of the devices, the calculation of instantaneous power and temperature of SiC dies, and the influence of the different PWM methods are presented. A 15-kVA inverter is built in order to obtain experimental results to confirm the characterization and loss calculation, and we show the best PWM methods to increase efficiency and reliability of the three-phase inverter for specific aircraft applications.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3033 ◽  
Author(s):  
Paweł Górecki ◽  
Krzysztof Górecki

This study proposes an electrothermal averaged model of the diode–transistor switch including insulated gate bipolar transistor (IGBT) and a rapid switching diode. The presented model has the form of subcircuits dedicated for simulation program with integrated circuit emphasis (SPICE) and it makes it possible to compute characteristics of DC–DC converters at the steady state considering self-heating phenomena, both in the diode and in IGBT. This kind of model allows computations of voltages, currents and internal temperatures of all used semiconductor devices at the steady state. The formulas used in this model are adequate for both: continuous conducting mode (CCM) and discontinuous conducting mode (DCM). Correctness of the proposed model is verified experimentally for a boost converter including IGBT. Good accuracy in modeling these converter characteristics is obtained.


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