Technologies and Trends to Improve Power Electronic Packaging

2011 ◽  
Vol 2011 (1) ◽  
pp. 000430-000437
Author(s):  
M. Schneider-Ramelow ◽  
M. Hutter ◽  
H. Oppermann ◽  
J.-M. Göhre ◽  
S. Schmitz ◽  
...  
Keyword(s):  
High Reliability ◽  
Transient Liquid Phase ◽  
Wire Bonding ◽  
Temperature Cycling ◽  
Material Behavior ◽  
Process Selection ◽  
Chip Surface ◽  
Bonding Parameters ◽  
Strong Trend ◽  
Die Attach

In the realm of power modules a strong trend toward high temperature and high reliability applications can be observed, which entails new technological challenges, especially for the assembly and packaging of power semiconductors. Because of the well known failure mechanisms of established lead-free standard soldering and heavy aluminum wire bonding technologies, such as fatigue and creep of die attach material and wire bonds at thermal cycling, academic and industrial research focuses on more reliable interconnection technologies. A priority is the research of alternative top and bottom side chip interconnection materials or technologies to improve the temperature cycling capability of power chips that are typically assembled on ceramic substrates. The scientific focus is on Ag sintering as die attach and/or heavy ribbon bonding, for example with Al or bi-metal (Al-Cu). Another focus is the material behavior of ribbon bonds in combination with bonding machine improvements (higher bonding parameters, cutting tool). But there are other very promising technologies like transient liquid phase bonding, for example with Cu-Sn or Ag-Sn systems or Cu heavy wire bonding (up to 400 μm wire diameter) or Cu/Al-Bi metal ribbon bonding. Challenges posed by these technologies have to be discussed focusing on materials and process selection and reliability issues. Process temperatures and temperature profiles must be optimized, wire bonding machines and the chip surface structures as well as finish metallizations need to be adapted. This paper will give an overview of alternative power chip interconnection technologies and discuss the challenges related to processing and reliability.

Intermittent Failures in High Pin Count Packaging

2006 ◽  
Author(s):  
Ramesh Varma ◽  
Richard Brooks ◽  
Ronald Twist ◽  
James Arnold ◽  
Cleston Messick
Keyword(s):  
Failure Analysis ◽  
Shape Analysis ◽  
State Of The Art ◽  
Process Variation ◽  
High Reliability ◽  
Temperature Cycling ◽  
Assembly Process ◽  
System Failures ◽  
Industrial Grade ◽  
Corrective Actions

Abstract In a prequalification effort to evaluate the assembly process for the industrial grade high pin count devices for use in a high reliability application, one device exhibited characteristics that, without corrective actions and/or extensive screening, may lead to intermittent system failures and unacceptable reliability. Five methodologies confirmed this conclusion: (1) low post-decapsulation wire pull results; (2) bond shape analysis showed process variation; (3) Failure Analysis (FA) using state of the art equipment determined the root causes and verified the low wire pull results; (4) temperature cycling parts while monitoring, showed intermittent failures, and (5) parts tested from other vendors using the same techniques passed all limits.

Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Xin Li ◽  
Xu Chen ◽  
Guo-Quan Lu
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Temperature Cycling ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Die Attach ◽  
Nanosilver Paste ◽  
Interconnection Material

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.

scholarly journals Development of high reliability semiconductor devices by copper wire bonding.

1988 ◽  
Vol 27 (4) ◽  
pp. 299-301
Author(s):  
J. Hirota ◽  
Y. Shibutani ◽  
T. Sugimura ◽  
K. Machida ◽  
T. Okuda
Keyword(s):  
High Reliability ◽  
Copper Wire ◽  
Semiconductor Devices ◽  
Wire Bonding ◽  
Copper Wire Bonding

Simulating the Effect of Rigid Frameworks on the Mechanical Properties of Transient Liquid Phase Sintered (TLPS) Alloys

2021 ◽  
Vol 2021 (HiTEC) ◽  
pp. 000089-000093
Author(s):  
Gilad Nave ◽  
Patrick McCluskey
Keyword(s):  
Liquid Phase ◽  
Effective Properties ◽  
Mechanical Strain ◽  
Transient Liquid Phase ◽  
Hazardous Substances ◽  
Automotive Electronics ◽  
Plastic Energy ◽  
Brittle Behavior ◽  
Die Attach ◽  
Transmission Electron

Abstract The need for power electronic devices and materials that can operate in harsh environments, together with the Restriction of Hazardous Substances (RoHS) legislation, has driven industry and researchers to develop new attach materials. Transient Liquid Phase Sintered (TLPS) joints are strong candidates to replace the current die attach materials due to their superior mechanical, thermal, and electrical properties. Despite these qualities, current TLPS systems may exhibit stiff and brittle behavior that can lead to die or attach fracture under large thermomechanical strains during wide temperature range cycling, or under mechanical stress from shock and vibration loading, such as is experienced in automotive electronics. This paper presents an approach for reducing thermal and mechanical strain levels by incorporating Transmission Electron Microscopy (TEM) Cu grids as a reinforcement to the attach material. The grids serve as ductile reinforcement capable of absorbing elastic and plastic energy, and as a barrier for crack propagations through the relative brittle TLPS material. Homogenization calculations were used to evaluate the effective properties of the TLPS, followed by numerical analysis that shows the effect of the grids on the die attach structure, and the mechanical integrity of the design.

Crystal Visco-Plastic Model for Ni-Base Superalloys Under Thermomechanical Fatigue

2020 ◽  
Author(s):  
Navindra Wijeyeratne ◽  
Firat Irmak ◽  
Ali P. Gordon ◽  
Jun-Young Jeon
Keyword(s):  
Kinematic Hardening ◽  
Thermomechanical Fatigue ◽  
Temperature Cycling ◽  
Material Behavior ◽  
Integration Scheme ◽  
Flow Rule ◽  
Anisotropic Behavior ◽  
Modeling Framework ◽  
Crystallographic Slip ◽  
Slip Planes

Abstract Gas turbine blades are subjected to complex mechanical loading coupled with extreme thermal loading conditions which range from room temperature to over 1000°C. Nickel-base superalloys exhibit high strength, good resistance to corrosion and oxidation, long fatigue life and is capable of withstanding high temperatures for extended periods of time. Consequently, Ni-base superalloys (NBSAs) are highly suitable as blading materials. The cyclic strains due to mechanical as well as thermal cycling leads to Thermomechanical fatigue (TMF). Damage from TMF takes the form of microstructural material cracking which consequently lead to the failure of the component. In order to increase the service life and reliability and reduce operating costs, development of simulations that accurately predict the material behavior for TMF is highly desirable. To support the mechanical design process, a framework consisting of theoretical mechanics, experimental analysis and numerical simulations must be used. Capturing the effects of thermomechanical fatigue is extremely important in the prediction of the material behavior and life expectation. Single crystal (SX) Ni-base superalloys exhibit anisotropic behavior. A modeling framework which is capable of simulating the physical attributes of the material microstructure is essential. Crystallographic slip along the slip planes controls the microstructural evolution of the material Crystal Visco-Plasticity (CVP) theory captures anisotropic behavior as well as the slip along the slip planes. CVP constitutive models can capture rate-, temperature, and history-dependence of these materials under a variety of conditions. Typical CVP formulations consist of a flow rule, internal state variables, and parameters. The model presented in the current study includes the inelastic mechanism of kinematic hardening and isotropic hardening which are captured by the back stress and drag stress, respectively. Crystallographic slip is accounted for by the incorporation of twelve octahedral six cubic slip systems. An implicit integration scheme which uses Newton-Raphson iteration method is used to solve the required solutions. The CVP model is implemented through a general-purpose finite element analysis software (i.e., ANSYS) as a User-Defined Material (USERMAT). A small batch of uniaxial experiments were conducted in key orientations (i.e., [001], [011], and [111] to assess the level of elastic and inelastic anisotropy. Modeling parameters are expressed as temperature-dependent to allow for simulation under non-isothermal conditions. An optimization scheme based in MATLAB utilizes this experimental data to calibrate the CVP modeling constants. The CVP model has the capability to simulate material behavior for monotonic and cyclic loading coupled with in phase and out phase temperature cycling for a variety of material orientations, strain rates, strain and temperature ranges. A CVP model that predicts SX behavior across various rates, orientations, temperatures and load levels have not been presented before now.

Die-Attach Voiding Reduction in Gold Alloy Solder Preforms

2017 ◽  
Vol 2017 (HiTEN) ◽  
pp. 000099-000102
Author(s):  
Bernard Leavitt ◽  
Andy C. Mackie
Keyword(s):  
High Temperature ◽  
Eutectic Alloy ◽  
Hot Spots ◽  
Gold Alloy ◽  
High Reliability ◽  
Eutectic Alloys ◽  
Power Semiconductor ◽  
Power Semiconductor Devices ◽  
Die Attach ◽  
Alloy Solder

Abstract The need for high-temperature solders is growing as RF and power semiconductor devices continue to get smaller, with power density increasing both as a consequence of the shrink and as a result of increased power ratings. AuSn20 eutectic solder (Indalloy®182) has been the workhorse for high-temperature, high-reliability, small die-attach applications for many years; however, as junction temperatures (Tj) increase, the gold-tin eutectic is beginning to reach its limit of utility. Higher temperatures cause increased thermal fatigue, and even delamination is seen at the solder joints. The next option for RF and power semiconductor manufacturers needing these higher temperatures is either AuGe12 (Indalloy®183) or AuSi3.2 (Indalloy®184) eutectic alloy (see Table I).Table 1.Key properties of Au-based eutectic alloys. Over the years, many customers have tried AuGe12 and the feedback has been that the alloy has poor solderability, which manifests as large voids in the bond. Voids are poor conductors of heat, which create hot spots, and are the primary cause of premature failures.

Embedded Die Packages and Modules for Power Electronics Applications

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 001918-001947 ◽  
Author(s):  
Lars Boettcher ◽  
S. Karaszkiewicz ◽  
D. Manessis ◽  
A. Ostmann
Keyword(s):  
Power Electronics ◽  
Power Efficiency ◽  
High Reliability ◽  
Heat Removal ◽  
Testing Temperature ◽  
Temperature Cycling ◽  
Switching Frequency ◽  
Large Area ◽  
Power Modules ◽  
Embedded Power

Packages and modules with embedded semiconductor dies are of interest for various application fields and power classes. First packages in the lower power range are available in volume production since almost six years. Recent developments focus on medium and higher power applications raging over 500W into the kW range. Different approaches are available to realize such packages and modules. This paper will give an overview and detailed description of the latest approaches for such embedded die structures. In common of all of these approaches, is the use of laminate based die embedding, which uses standard PCB manufacturing technologies. Main differences are the used base substrate, which can still be a ceramic (DBC), Cu leadframe or high current substrate. Examples for the different methods will be given. As the main part, this paper will describe concepts, which enable significant smaller form-factor of power electronics modules, thereby allowing for lower price, high reliability, capability of direct mounting on e.g. a motor so as to form one unit with the motor housing, wide switching frequency range (for large application field) and high power efficiency. The innovative character of this packaging concept is the idea to embed the power drive components (IGBTs, MOSFETs, diode) as thinned chips into epoxy-resin layer built-up and to realize large-area interconnections on both sides by direct copper plating the dies to form a conductor structure with lowest possible electrical impedance and to achieve an optimum heat removal. In this way a thin core is formed on a large panel format which is called Embedded Power Core. The paper will specifically highlight the first results on manufacturing an embedded power discrete package as an example of an embedded power core containing a thin rectifier diode. For module realization, the power cores are interconnected to insulated metal substrates (IMS) by the use of Ag sintering interconnection technologies for the final manufacturing of Power modules. The paper will elaborate on the sintering process for Power Core/IMS interconnections, the microscopically features of the sintered interfaces, and the lateral filling of the sintering gap with epoxy prepregs. Firstly, 500W power modules were manufactured using this approach. Reliability testing results, solder reflow testing, temperature cycling test and active power cycling, will be discussed in detail.

Automated Precision Assembly for High-Volume HB LEDs

2011 ◽  
Vol 2011 (1) ◽  
pp. 000117-000122
Author(s):  
Donald J. Beck ◽  
Jessica Sylvester
Keyword(s):  
Light Emitting Diode ◽  
High Reliability ◽  
Bright Light ◽  
High Volume ◽  
Commercial Production ◽  
Production Lines ◽  
Light Emitting ◽  
Die Attach ◽  
High Volume Production ◽  
Volume Production

Since the introduction of automated die and wire bonders in the 1980s, equipment manufacturers and process engineers have been challenged to balance speed with repeatability. Today, die bonders can perform epoxy die attach at a rate of 1.5 to 4 thousand die per hour [6]; and wire bonders can interconnect complex packages at speeds of more than 10 wires per second [7]. The advantage of automation is speed and consistency—however, there is one major concern with operating at these speeds: if something in the assembly process is wrong, everything will be wrong. Having tightly regulated assembly processes helps avoid the risk of building a large batch of rejected product. This paper presents a methodology and process flow supporting High Bright Light Emitting Diode (HB LED) automated assembly, supported by equipment certification, product inspection and SPC data collection methods. The methods presented in this paper have been formulated through extensive work in the high-reliability microelectronics industry and commercial production lines over the last three decades. To ensure time-to-market success in high-volume production, specific methods to achieve throughput and quality are required. This paper will cover the strategies and methods necessary to achieve the ultimate goal of an automated precision HB LED assembly—to blend the requirements of high-reliability and high-throughput to support high-volume commercial production.

LT-TLPS Die Attach for High Temperature Electronic Packaging

2014 ◽  
Vol 11 (1) ◽  
pp. 7-15
Author(s):  
Hannes Greve ◽  
F. Patrick McCluskey
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Melting Point ◽  
Low Temperature ◽  
Transient Liquid Phase ◽  
Liquid Phase Sintering ◽  
Die Attach ◽  
Metallic Interfaces ◽  
Dsc Analyses ◽  
Transient Liquid Phase Sintering

Low temperature transient liquid phase sintering (LT-TLPS) can be used to form high-temperature joints between metallic interfaces at low process temperatures. In this paper, process analyses and shear strength studies of paste-based approaches to LT-TLPS are presented. The process progression studies include DSC analyses and observations of intermetallic compound (IMC) formation by cross-sectioning. It was found that the sintering process reaches completion after sintering times of 15 min for process temperatures approximately 50°C above the melting point of the low temperature constituent. For the shear studies, test samples consisting of copper dice and copper substrates joined by sintering with a variety of sinter pastes with different ratios of copper and tin have been assessed. A fixture was designed for high temperature enabled shear tests at 25°C, 125°C, 250°C, 400°C, and 600°C. The influence of the ratio of the amount of high melting-point constituent to the amount of low melting-point constituent on the maximum application temperature of the sinter paste was analyzed. Ag20Sn and Cu50Sn pastes showed no reduction in shear strength up to 400°C, and Cu40Sn pastes showed high shear strengths up to 600°C. It was shown that LT-TLPS can be used to form high temperature stable joints at low temperatures without the need to apply pressure during processing.

Manufacturability and Reliability Screening of Lower Melting Point, Pb-Free Alloys Containing Bismuth

2015 ◽  
Vol 12 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Joseph M. Juarez ◽  
Polina Snugovsky ◽  
Eva Kosiba ◽  
Zohreh Bagheri ◽  
Subramaniam Suthakaran ◽  
...  
Keyword(s):  
High Reliability ◽  
Temperature Cycling ◽  
Vibration Testing ◽  
Excellent Performance ◽  
Test Conditions ◽  
Surface Finishes ◽  
Before And After ◽  
Microstructure Examination ◽  
Lower Melting Point ◽  
Failure Monitoring

This paper explores the manufacturability and reliability of three Pb-free Bi-containing alloys in comparison with conventional SAC305 and SnPb assemblies. The first alloy included in the study is a Sn-based alloy with 3.4%Ag and 4.8%Bi, which showed promising results in the National Center for Manufacturing Sciences and German Joint projects. The other two alloy variations have reduced Ag content, with and without Cu. BGA and leaded components were assembled on medium-complexity test vehicles using these alloys, as well as SAC305 and SnPb as baseline alloys, for comparison. Test vehicles were manufactured using two board materials, 170°C glass transition temperature (Tg) and 155°C Tg, with three surface finishes: ENIG, ENEPIG, and OSP. The accelerated temperature cycling (ATC) testing was done at −55°C to 125°C with 30-min dwells and 10°C/min ramps, for 3,000 cycles. Detailed microstructure examination before and after ATC testing is described, as is failure analysis. All three experimental alloys showed excellent performance in harsh-environment thermal cycling. Vibration testing at two G-force test conditions with resistance failure monitoring was performed on the daisy-chained components. A detailed description of the technique for the vibration testing using 2 G and 5 G harmonic dwells is provided. The lowest failure rate found at both the 2 G and 5 G levels was for the Cu-containing alloy known as Violet. These results provide data for further statistical analysis leading to the choice of proper combinations of the solder alloys, board materials, and surface finishes for high-reliability applications.

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