In-depth investigation of metallization aging in power MOSFETs

Ruffilli, Roberta; Berkani, Mounira; Dupuy, Philippe; Lefebvre, Stéphane; Weber, Yann; Legros, Marc

doi:10.1016/j.microrel.2015.06.036

Cited by 13 publications

(10 citation statements)

References 13 publications

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“…The amount of plastic deformation does not change significantly, in line with previous results [9]. Fig.…”

Section: Al Metallization Under the Bonding Wiressupporting

confidence: 92%

“…They follow the grain boundaries, confirming that aging is linked to an enhanced self-diffusion of Al atoms along the boundaries [10,11]. Moreover aging seems to lower the average grain size but, as we also observed in a previous work [9], ACOM mapping (Fig. 8) shows that most of the grain domains revealed by FIB have a small misorientation (less than 10°).…”

Section: Al Metallization Away From the Bonding Areasupporting

confidence: 87%

“…In a previous study [9], we have shown that power MOSFETs aging occurs through a change in the Al grain microstructure and that plastic deformation of the top metal is due to an enhanced self-diffusion of the Al atoms along the grain boundaries [10,11]. We have also compared the initial Al metallization microstructure away from the bonding area and just under the bond wires: the latter is severely deformed, due to the bonding process.…”

Section: Introductionmentioning

confidence: 96%

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Aluminum metallization and wire bonding aging in power MOSFET modules

Ruffilli

Berkani

Dupuy³

et al. 2018

Materials Today: Proceedings

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A limiting factor for the long-term reliability of power MOSFET-based devices is the electro-thermal and/or thermo-mechanical aging of the metallic parts. In this paper we assess the bonding wire and source metallization degradation of power devices, designed for applications in the automotive industry. Our approach consists in characterizing the metal microstructure before and after accelerated aging tests, by scanning electron microscopy, ion milling and microscopy, focused ion beam tomography, transmission electron microscopy and grain structure mapping. To focus on the wire-metallization bonding interface, we have set up a dedicated sample preparation that allows us to disclose the metallization under the bonding wires. This critical location is significantly different from the naked metallization, as the bonding process induces plastic deformation prior to aging. The main mechanism behind the device failure is the generation and propagation of fatigue cracks in the aluminum metallization. Away and under the wire bonds, they run perpendicularly from the surface down to the silicon substrate following the grain boundaries, due to an enhanced self-diffusion of aluminum atoms. Moreover, initial imperfections in the wire-metallization bonding (small cavities and aluminum oxide residues) are the starting point for harmful cracks that propagate along the wire-metallization interface and can eventually cause the wire lift-off. These phenomena can explain the local increase in the device resistance occurring at failure.

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“…The amount of plastic deformation does not change significantly, in line with previous results [9]. Fig.…”

Section: Al Metallization Under the Bonding Wiressupporting

confidence: 92%

Section: Al Metallization Away From the Bonding Areasupporting

confidence: 87%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Aluminum metallization and wire bonding aging in power MOSFET modules

Ruffilli

Berkani

Dupuy³

et al. 2018

Materials Today: Proceedings

Self Cite

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show abstract

“…This section takes the metaloxidesemiconductor fieldEffect transistor (MOSFET) as an example and summa rizes the general process of the TEM sample preparation based on FIB-SEM. [59][60][61] Six main steps of the TEM sample prepa ration based on FIB-SEM are illustrated in Figure 4. First, a carbon (C) or platinum (Pt) strap is deposited on the observa tion area by an ion beam or electron beam before cutting.…”

Section: Traditional Fib-sem Sample Preparation Methods For Devicesmentioning

confidence: 99%

The Trends of In Situ Focused Ion Beam Technology: Toward Preparing Transmission Electron Microscopy Lamella and Devices at the Atomic Scale

Zhang

Wang

Dong

et al. 2022

Adv Elect Materials

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The increased complexity and scaling down of electronic devices lead to great challenges in extracting an interesting nanoscale area of the device for transmission electron microscopy (TEM) characterization. The traditional TEM sample preparation methods, such as electrolytic polishing, can not precisely process a specific area of the device. Focused ion beam (FIB) technology is an advanced in situ specimen preparation method for TEM. FIB can not only locate specific position and mill a TEM sample with the nanoscale resolution, but also manipulate the sample in a controlled manner in real time. With the development of electronic devices, variations, and optimizations of the FIB method for advanced devices with new structures have been reported. In this review, the TEM sample preparation methods for fin field‐effect transistor, high electron mobility transistor, enhanced dynamic random‐access memory, and 2D material‐based devices are discussed. Their advantages, disadvantages, and an overview of the applications are summarized. Based on current research, future research directions for enhancing the quality of TEM samples are suggested.

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“…In this case, the latter has been chosen due to providing more control over inputs such as the dimensions of the component and constitutive material models as well as the boundary conditions. According to literature, the active switching devices, being the MOSFETs, are more prone to failure than the other components when not using aluminum electrolytic capacitors in the design [34,35]. Specifically the bond wires and the die-attach are sensitive to the thermal stress generated by the discrepancy in coefficients of thermal expansion (CTE) of the different materials [36].…”

Section: Constructing a Fem Mosfet Modelmentioning

confidence: 99%

The Sensitivity of an Electro-Thermal Photovoltaic DC–DC Converter Model to the Temperature Dependence of the Electrical Variables for Reliability Analyses

et al. 2020

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The operational expenditures of solar energy are gaining attention because of the continuous decrease of the capital expenditures. This creates a demand for more reliable systems to further decrease the costs. Increased reliability is often ensured by iterative use of design for reliability. The number of iterations that can take place strongly depends on the computational efficiency of this methodology. The main research objective is to quantify the influence of the temperature dependence of the electrical variables used in the electro-thermal model on the reliability and the computation time. The influence on the reliability is evaluated by using a 2-D finite elements method model of the MOSFET and calculating the plastic energy dissipation density in the die-attach and the bond wire. The trade-off between computation time of the electro-thermal model in PLECS (4.3, Plexim, Zurich, Switzerland) and generated plastic energy accuracy obtained in COMSOL (5.3, COMSOL Inc., Burlington, MA, USA) is reported when excluding a certain temperature dependence. The results indicate that the temperature dependence of the input and output capacitors causes no change in the plastic energy dissipated in the MOSFET but does introduce the largest increase in computation time. However, not including the temperature dependence of the MOSFET itself generates the largest difference in plastic energy of 10% as the losses in the die are underestimated.

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In-depth investigation of metallization aging in power MOSFETs

Cited by 13 publications

References 13 publications

Aluminum metallization and wire bonding aging in power MOSFET modules

Aluminum metallization and wire bonding aging in power MOSFET modules

The Trends of In Situ Focused Ion Beam Technology: Toward Preparing Transmission Electron Microscopy Lamella and Devices at the Atomic Scale

The Sensitivity of an Electro-Thermal Photovoltaic DC–DC Converter Model to the Temperature Dependence of the Electrical Variables for Reliability Analyses

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