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JournalISSN: 1043-7398

Journal of Electronic Packaging 

ASM International
About: Journal of Electronic Packaging is an academic journal published by ASM International. The journal publishes majorly in the area(s): Heat transfer & Heat sink. It has an ISSN identifier of 1043-7398. Over the lifetime, 1989 publications have been published receiving 36119 citations.


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Journal ArticleDOI
TL;DR: In this paper, a unified viscoplastic constitutive law, the Anand model, was applied to represent the inelastic deformation behavior for solders used in electronic packaging.
Abstract: A unified viscoplastic constitutive law, the Anand model, was applied to represent the inelastic deformation behavior for solders used in electronic packaging. The material parameters of the constitutive relations for 62Sn36Pb2Ag, 60Sn40Pb, 96.5Sn3.5Ag, and 97.5Pb2.5Sn solders were determined from separated constitutive relations and experimental results. The achieved unified Anand model for solders were tested for constant strain rate testing, steady-state plastic flow and stress/strain responses under cyclic loading. It is concluded that the Anand model can be applied for representing the inelastic deformation behavior of solders at high homologous temperature and can be recommended for finite element simulation of the stress/strain responses of solder joints in service. @DOI: 10.1115/1.1371781#

307 citations

Journal ArticleDOI
TL;DR: In this article, a review of the most commonly used measurement techniques for thermal conductivity and interfacial thermal conductance is presented, including the 3-omega method and transient plane source method.
Abstract: Thermal conductivity and interfacial thermal conductance play crucial roles in the design of engineering systems where temperature and thermal stress are of concerns. To date, a variety of measurement techniques are available for both bulk and thin film solid-state materials with a broad temperature range. For thermal characterization of bulk material, the steady-state absolute method, laser flash diffusivity method, and transient plane source method are most used. For thin film measurement, the 3{\omega} method and transient thermoreflectance technique including both frequency-domain and time-domain analysis are employed widely. This work reviews several most commonly used measurement techniques. In general, it is a very challenging task to determine thermal conductivity and interface contact resistance with less than 5% error. Selecting a specific measurement technique to characterize thermal properties need to be based on: 1) knowledge on the sample whose thermophysical properties is to be determined, including the sample geometry and size, and preparation method; 2) understanding of fundamentals and procedures of the testing technique and equipment, for example, some techniques are limited to samples with specific geometrics and some are limited to specific range of thermophysical properties; 3) understanding of the potential error sources which might affect the final results, for example, the convection and radiation heat losses.

306 citations

Journal ArticleDOI
Issam Mudawar1
TL;DR: In this paper, the performance of two-phase micro-channel heat sinks has been investigated in a wide range of applications, such as computer, fusion, and rocket nozzles.
Abstract: Boiling water in small channels that are formed along turbine blades has been examined since the 1970s as a means to dissipating large amounts of heat. Later, similar geometries could be found in cooling systems for computers, fusion reactors, rocket nozzles, avionics, hybrid vehicle power electronics, and space systems. This paper addresses (a) the implementation of two-phase microchannel heat sinks in these applications, (b) the fluid physics and limitations of boiling in small passages, and effective tools for predicting the thermal performance of heat sinks, and (c) means to enhance this performance. It is shown that despite many hundreds of publications attempting to predict the performance of two-phase microchannel heat sinks, there are only a handful of predictive tools that can tackle broad ranges of geometrical and operating parameters or different fluids. Development of these tools is complicated by a lack of reliable databases and the drastic differences in boiling behavior of different fluids in small passages. For example, flow boiling of certain fluids in very small diameter channels may be no different than in macrochannels. Conversely, other fluids may exhibit considerable “confinement” even in seemingly large diameter channels. It is shown that cutting-edge heat transfer enhancement techniques, such as the use of nanofluids and carbon nanotube coatings, with proven merits to single-phase macrosystems, may not offer similar advantages to microchannel heat sinks. Better performance may be achieved by careful optimization of the heat sink’s geometrical parameters and by adapting a new class of hybrid cooling schemes that combine the benefits of microchannel flow with those of jet impingement. [DOI: 10.1115/1.4005300]

248 citations

Journal ArticleDOI
TL;DR: In this article, a generalized solder joint fatigue life model based on correlation to measured crack growth data on BGA joints during thermal cycling has been presented for surface mount packages, and the model has been successfully applied to TSOP, CQFP, CBGA, PBGA and power hybrid packages.
Abstract: A generalized solder joint fatigue life model for surface mount packages was previously published in Refs [1,2]. The model is based on correlation to measured crack growth data on BGA joints during thermal cycling. It was subsequently discovered by Anderson et.al. that the ANSYS 5.2 finite element code used in the model had an error in its method for calculating plastic work [3]. It was shown that significant error in life prediction could result by using a recent version of the code where the bug has been fixed. The error comes about since the original crack growth constants were derived based on plastic work calculations that had the bug. In this paper, crack initiation and growth constants are recalculated using ANSYS 5.6. In addition, several other model related issues are explored with respect to the crack growth correlations. For example, 3D slice models were compared to quarter symmetry models. Anand’s constitutive model was compared with Darveaux’s constitutive model. It was shown that the crack growth rate dependence on strain energy density always had an exponent of 1.10 +/0.15. This is in the range of the original correlation, so the accuracy of relative predictions should still be within +/25%. However, the accuracy of absolute predictions could be off by a factor of 7 in the worst case, if the analyst uses a modeling procedure that is not consistent with that used for the crack growth correlation. The key to good accuracy is to maintain consistency in the modeling procedure. Introduction Analytical models in engineering have several practical uses: 1) rapid design optimization during the development phase of a product, 2) predicting field use limits, and 3) failure analysis of product returned from the field or failed in a qualification test. The solder joint fatigue model presented here was first published in Ref [1]. An outline of the procedure to predict fatigue life is shown schematically in Figure 1. The model utilizes finite element analysis to calculate the inelastic strain energy density accumulated per cycle during thermal or power cycling. The strain energy density is then used with crack growth data to calculate the number of cycles to initiate a cracks, and the number of cycles to propagate cracks through a joint. In reference [2], more work was presented regarding sensitivity of the life prediction to the FEA procedure. As a result, the procedure was modified slightly to include volume averaging of the strain energy values near the joint interface. The model has been successfully applied to TSOP, CQFP, CBGA, PBGA, and power hybrid packages [1,2,4-9]. Calculate Strain Energy Density Accumulated per Cycle Calculate Number of Cycles to Crack Initiation Calculate Crack Growth Rate Calculate Fatigue Life Based on Joint Length Figure 1. Solder joint fatigue life prediction method. It was subsequently discovered by Anderson et.al. that ANSYS 5.5.2 and earlier versions of the finite element code had an error in their method for calculating plastic work [3]. Even though there had generally been good correlation to measured results, it was shown that significant error in life prediction could result by using a recent version of the code where the bug has been fixed (e.g. ANSYS 5.5.3 and later versions). The error comes about since the original crack growth constants were derived based on plastic work calculations that had the bug. In this paper, crack initiation and growth constants are recalculated using ANSYS 5.6. In addition, several other model related issues are explored with respect to the crack growth correlations. Several recommendations are made so the analyst can get accurate results more efficiently. Constitutive Relations Since solder is above half of its melting point at room temperature, creep processes are expected to dominate the deformation kinetics. Steady state creep of solder can be expressed by a relationship of the form [10-12] dεs dt = Css[sinh(ασ)] n exp( -Qa kT ) (1) where dεs/dt is the steady state strain rate, k is Boltzmann's constant, T is the absolute temperature, σ is the applied stress, Qa is the apparent activation energy, n is the stress exponent, α prescribes the stress level at which the power law dependence breaks down, and Css is a constant. Steady state creep data for 62Sn36Pb2Ag solder joints is shown in Figure 2.

238 citations

Performance
Metrics
No. of papers from the Journal in previous years
YearPapers
202323
202276
202163
202069
201947
201842