The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Kazuhiro Nogita - One of the best experts on this subject based on the ideXlab platform.
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shear and tensile impact strength of lead free solder Ball Grid Arrays placed on ni p au surface finished substrates
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2010Co-Authors: Hideaki Tsukamoto, Tetsuro Nishimura, Shoichi Suenaga, Kazuhiro NogitaAbstract:This study aims to investigate the shear and tensile impact behavior of Ball Grid Arrays (BGAs) placed on Ni (P)/Au surface-finished substrates considering the microstructure and compositions of intermetallic compounds (IMCs) formed at the solder/substrate interfaces. Tests were conducted on as-reflowed and aged samples with four different compositions of solders such as Ni-doped and non-Ni-doped Sn-0.7 wt.%Cu, Sn-37 wt.%Pb and Sn-3.0 wt.%Ag-0.5 wt.%Cu, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. In shear tests, there was almost no difference between as-reflowed and aged samples at low displacement rates in all the samples, while at high displacement rates the aged samples showed better properties than as-reflowed ones, in particular, in Ni-doped Sn-0.7wt%Cu samples. In tensile tests, the aging treatments had little effect on the strength for any compositions of solders at low and high displacement rates. Sn-3.0 wt.%Ag-0.5 wt.%Cu samples with any heat treatments showed the least resistance to both shear and tensile loadings at any displacement rates.
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nanoindentation characterization of intermetallic compounds formed between sn cu ni Ball Grid Arrays and cu substrates
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2009Co-Authors: Hideaki Tsukamoto, Zhigang Dong, Ha Huang, Tetsuro Nishimura, Kazuhiro NogitaAbstract:The formation of intermetallic compounds (IMCs) at the solder-substrate interface is essential in the manufacturing of solder joints. In this study, the effect of Ni addition into Sn-Cu lead-free solders on mechanical properties of the IMCs formed at the interface between solder Ball Grid Arrays (BGAs) and Cu substrates, which experienced multiple reflows, were investigated. The results from nanoindentation tests showed that elastic modulus and hardness of (Cu,Ni)(6)Sn(5) were higher than those of Cu(6)Sn(5). The hardnesses of (Cu,Ni)(6)Sn(5) were more scattered compared to those of Cu(6)Sn(5). which may be attributed to the crystallographic characteristics such as growth texture of the IMCs. (C) 2009 Elsevier B.V. All rights reserved.
Hideaki Tsukamoto - One of the best experts on this subject based on the ideXlab platform.
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shear and tensile impact strength of lead free solder Ball Grid Arrays placed on ni p au surface finished substrates
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2010Co-Authors: Hideaki Tsukamoto, Tetsuro Nishimura, Shoichi Suenaga, Kazuhiro NogitaAbstract:This study aims to investigate the shear and tensile impact behavior of Ball Grid Arrays (BGAs) placed on Ni (P)/Au surface-finished substrates considering the microstructure and compositions of intermetallic compounds (IMCs) formed at the solder/substrate interfaces. Tests were conducted on as-reflowed and aged samples with four different compositions of solders such as Ni-doped and non-Ni-doped Sn-0.7 wt.%Cu, Sn-37 wt.%Pb and Sn-3.0 wt.%Ag-0.5 wt.%Cu, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. In shear tests, there was almost no difference between as-reflowed and aged samples at low displacement rates in all the samples, while at high displacement rates the aged samples showed better properties than as-reflowed ones, in particular, in Ni-doped Sn-0.7wt%Cu samples. In tensile tests, the aging treatments had little effect on the strength for any compositions of solders at low and high displacement rates. Sn-3.0 wt.%Ag-0.5 wt.%Cu samples with any heat treatments showed the least resistance to both shear and tensile loadings at any displacement rates.
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nanoindentation characterization of intermetallic compounds formed between sn cu ni Ball Grid Arrays and cu substrates
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2009Co-Authors: Hideaki Tsukamoto, Zhigang Dong, Ha Huang, Tetsuro Nishimura, Kazuhiro NogitaAbstract:The formation of intermetallic compounds (IMCs) at the solder-substrate interface is essential in the manufacturing of solder joints. In this study, the effect of Ni addition into Sn-Cu lead-free solders on mechanical properties of the IMCs formed at the interface between solder Ball Grid Arrays (BGAs) and Cu substrates, which experienced multiple reflows, were investigated. The results from nanoindentation tests showed that elastic modulus and hardness of (Cu,Ni)(6)Sn(5) were higher than those of Cu(6)Sn(5). The hardnesses of (Cu,Ni)(6)Sn(5) were more scattered compared to those of Cu(6)Sn(5). which may be attributed to the crystallographic characteristics such as growth texture of the IMCs. (C) 2009 Elsevier B.V. All rights reserved.
Nogita K. - One of the best experts on this subject based on the ideXlab platform.
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Effects of Bi in Sn-Cu based lead-free solder alloys and interconnects
'Institute of Electrical and Electronics Engineers (IEEE)', 2017Co-Authors: Nogita K., Mcdonald S. D., Salleh M. A. A. Mohd, Smith S., Wu Y. Q., Ab Razak A. G., Akaiwa T., Nishimura T.Abstract:Additions of 1.5wt%Bi to Sn-0.7Cu-0.05Ni (SN100C) were investigated for their influence on mechanical properties and the IMC layer formed between the solder and Cu substrates. Solder Balls of Sn-0.7Cu (Sn07Cu), SN100C, Sn-0.7Cu-0.05Ni-1.5Bi (SN100CV) and Sn-3Ag-0.5Cu (SAC) were reflowed onto Cu Ball Grid Arrays (BGAs). They were examined in the as reflowed condition and after a heat treatment of annealing at 150°C up to 1,500 hours. The mechanical properties of SN100C, SN100CV and SAC solder Balls were investigated by nano-indentation, and cross-sections of the interfacial IMC layer were observed by SEM to determine the morphology and average interfacial IMC layer thickness. It was found that the effect of Bi additions was to increase the lattice parameters and alter the mechanical properties. The near-eutectic microstructure and suppression of Cu Sn at the IMC layer that are associated with Ni additions are not altered by the presence of 1.5wt%Bi
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The influence of solder composition on the impact strength of lead-free solder Ball Grid array joints
'Elsevier BV', 2011Co-Authors: Tsukamoto H., Nishimura T., Suenaga S., Mcdonald S. D., Sweatma K. W., Nogita K.Abstract:This study aims to investigate the shear and tensile impact strength of solder Ball attachments. Tests were conducted on Ni-doped and non-Ni-doped Sn–0.7wt.% Cu, Sn–37wt.% Pb and Sn–3.0wt.% Ag–0.7wt.% Cu solder Ball Grid Arrays (BGAs) placed on Cu substrates, which were as-reflowed and aged, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. Ni additions to the Sn–0.7wt.% Cu solders has slowed the growth of the interface intermetallic compounds (IMCs) and made the IMC layer morphology smooth. As-reflowed Ni-doped Sn–0.7wt.% Cu BGA joints show superior properties at high speed shear and tensile impacts compared to the non-Ni-doped Sn–0.7wt.% Cu and Sn–3.0wt.% Ag–0.7wt.% Cu BGAs. Sn–3.0wt.% Ag–0.7wt.% Cu BGAs exhibit the least resistance in both shear and tensile tests among the four compositions of solders, which may result from the cracks in the IMC layers introduced during the reflow processes
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Shear and tensile impact strength of lead-free solder Ball Grid Arrays placed on Ni (P)/Au surface-finished substrates
'Elsevier BV', 2010Co-Authors: Tsukamoto H., Nishimura T., Suenaga S., Nogita K.Abstract:This study aims to investigate the shear and tensile impact behavior of Ball Grid Arrays (BGAs) placed on Ni (P)/Au surface-finished substrates considering the microstructure and compositions of intermetallic compounds (IMCs) formed at the solder/substrate interfaces. Tests were conducted on as-reflowed and aged samples with four different compositions of solders such as Ni-doped and non-Ni-doped Sn-0.7 wt.%Cu, Sn-37 wt.%Pb and Sn-3.0 wt.%Ag-0.5 wt.%Cu, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. In shear tests, there was almost no difference between as-reflowed and aged samples at low displacement rates in all the samples, while at high displacement rates the aged samples showed better properties than as-reflowed ones, in particular, in Ni-doped Sn-0.7wt%Cu samples. In tensile tests, the aging treatments had little effect on the strength for any compositions of solders at low and high displacement rates. Sn-3.0 wt.%Ag-0.5 wt.%Cu samples with any heat treatments showed the least resistance to both shear and tensile loadings at any displacement rates
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Ball impact behavior of Sn-Cu (-Ni) lead-free solder joints
2009Co-Authors: Tsukamoto Hideaki, Nishimura T., Suenaga S., Mcdonald S. D., Read J., Nogita K.Abstract:Recent environmental and health concerns regarding the toxicity of lead have facilitated the development of lead-free solder alloys with suitable soldering characteristics and mechanical properties. Compared to the lead-containing solders, however, the lead-free solders are stiffer and less deformable during dynamic loading. In the present study, the shear and pull Ball tests were employed to evaluate the impact strength of solder Ball attachments. Tests were conducted on as-reflowed and aged Ni-doped and non-Ni-doped Sn-Cu solder Ball Grid Arrays (BGAs) placed on Cu substrates over a wide range of displacement rates. Trace Ni addition to the Sn-Cu solders prevented the growth of the interface intermetallic compounds (IMCs) and made the IMC layer morphology smooth. As-reflowed Sn-Cu-Ni BGA joints show superior properties in high speed shear and pull impact tests
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Nanoindentation characterization of intermetallic compounds formed at Sn-Cu (-Ni) solder/Cu substrate interfaces
2008Co-Authors: Tsukamoto H., Nishimura T., Dong Z., Huang H., Nogita K.Abstract:The formation of intermetallic compounds (IMCs) at solder/substrate interfaces is essential, which have a critical effect on the mechanical reliability of solder joints. In this study, nanoindentation was used to investigate elastic modulus, hardness and creep properties of the IMCs formed at the interface between Sn-Cu (-Ni) solder Ball Grid Arrays (BGAs) and Cu substrates in multiple-reflowed samples. All the tests were conducted at room temperature. The elastic modulus and hardness of (Cu,Ni)Sn were higher than those of CuSn. The hardnesses of (Cu,Ni)Sn were scattered, which may be attributed to the crystallographic characteristics such as a growth texture of the IMCs. The creep stress exponents of the IMCs were extremely high (9.5∼44), compared to pure tin and solder alloys
Tetsuro Nishimura - One of the best experts on this subject based on the ideXlab platform.
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shear and tensile impact strength of lead free solder Ball Grid Arrays placed on ni p au surface finished substrates
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2010Co-Authors: Hideaki Tsukamoto, Tetsuro Nishimura, Shoichi Suenaga, Kazuhiro NogitaAbstract:This study aims to investigate the shear and tensile impact behavior of Ball Grid Arrays (BGAs) placed on Ni (P)/Au surface-finished substrates considering the microstructure and compositions of intermetallic compounds (IMCs) formed at the solder/substrate interfaces. Tests were conducted on as-reflowed and aged samples with four different compositions of solders such as Ni-doped and non-Ni-doped Sn-0.7 wt.%Cu, Sn-37 wt.%Pb and Sn-3.0 wt.%Ag-0.5 wt.%Cu, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. In shear tests, there was almost no difference between as-reflowed and aged samples at low displacement rates in all the samples, while at high displacement rates the aged samples showed better properties than as-reflowed ones, in particular, in Ni-doped Sn-0.7wt%Cu samples. In tensile tests, the aging treatments had little effect on the strength for any compositions of solders at low and high displacement rates. Sn-3.0 wt.%Ag-0.5 wt.%Cu samples with any heat treatments showed the least resistance to both shear and tensile loadings at any displacement rates.
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nanoindentation characterization of intermetallic compounds formed between sn cu ni Ball Grid Arrays and cu substrates
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2009Co-Authors: Hideaki Tsukamoto, Zhigang Dong, Ha Huang, Tetsuro Nishimura, Kazuhiro NogitaAbstract:The formation of intermetallic compounds (IMCs) at the solder-substrate interface is essential in the manufacturing of solder joints. In this study, the effect of Ni addition into Sn-Cu lead-free solders on mechanical properties of the IMCs formed at the interface between solder Ball Grid Arrays (BGAs) and Cu substrates, which experienced multiple reflows, were investigated. The results from nanoindentation tests showed that elastic modulus and hardness of (Cu,Ni)(6)Sn(5) were higher than those of Cu(6)Sn(5). The hardnesses of (Cu,Ni)(6)Sn(5) were more scattered compared to those of Cu(6)Sn(5). which may be attributed to the crystallographic characteristics such as growth texture of the IMCs. (C) 2009 Elsevier B.V. All rights reserved.
Pradeep Lall - One of the best experts on this subject based on the ideXlab platform.
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effect of mean temperature on the evolution of strain amplitude in sac Ball Grid Arrays during operation under thermal aging and temperature excursions
Electronic Components and Technology Conference, 2017Co-Authors: Pradeep Lall, Jeff Suhling, Kazi Mirza, David LockeAbstract:Electronics in automotive applications may be used for a number of safety critical systems including lane-departure warning, collision avoidance, drive assist systems, and adaptive cruise control. Furthermore, electronics in fully-electric vehicles may be used for power generation and management. Automotive electronics may be mounted on engine or on transmission or in the base of the automobile and may be subjected to operational temperature excursions in addition to environmental temperature extremes. Further, automotive electronics systems may be subjected to prolonged periods of storage at ambient environmental low or high temperatures. There is need for tools and techniques for proactive assessment of consumed life, remaining useful-life, and spot assessment of thermo-mechanical reliability of electronics to assure reliable operation for the automotive benchmark of 10-years, 100,000 miles. In this study, the effect of thermal aging on thermal cycling reliability and the evolution of strain has been studied using digital image correlation. Leadfree assemblies which have been subjected to prolonged periods of aging have been subsequently subjected to thermal cycling and the strain amplitude experienced in the solder joints has been measured using digital image correlation. These strain state results then were correlated with microstructural damage rate (obtained from a separate study) to develop a damage mapping model. Finally, a new approach of life model along with Remaining Useful Life (RUL) estimation technique has been presented based upon microstructural damage rate.
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Principal component regression models for life prediction of plastic Ball Grid Arrays on copper-core and no-core assemblies
2008 11th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems I-THERM, 2008Co-Authors: Pradeep Lall, Aniket Shirgaokar, Luke Drake, Timothy Moore, Jeff Suhling, Milan ShahAbstract:In this paper, principal component regression models (PCR) have been investigated for reliability prediction and part selection of area package architectures under thermo- mechanical loads in conjunction with stepwise regression methods. Package architectures studied include, BGA packages mounted on CU-CORE and NO-CORE printed circuit assemblies in harsh environments. The models have been developed based on thermo-mechanical reliability data acquired on copper-core and no-core assemblies in four different thermal cycling conditions. Solder alloys examined include SnPb and SAC Alloys. The models presented in this paper provide decision guidance for smart selection and substitution to address component obsolescence by perturbing product designs for minimal risk insertion of new packaging technologies. It is conceivable for commercial off the shelf parts to become unavailable during the production-life of a product. Typical Commercial-of-the-Shelf parts are manufactured for a period of two to four years, and IC manufacturing processes are available for five to six years. It is envisioned that the reliability assessment models will enable turn-key evaluation of geometric architecture, material properties, and operating conditions effects on thermo-mechanical reliability. The presented approach enables the evaluation of qualitative parameter interaction effects, which are often ignored in closed-form modeling, have been incorporated in this work. Previously, the feasibility of using multiple linear regression models for reliability prediction has been demonstrated for flex-substrate BGA packages [1, 2], flip-chip packages [3, 4] and ceramic BGA packages [5] Convergence of statistical models with experimental data and finite element models has been demonstrated using a single factor design of experiment study. In addition, the power-law dependencies of individual variables have been correlated with established failure mechanics models. PCR approach uses the potentially im-\nportant variables from stepwise regression. The statistics models are based on accelerated test data acquired as part of this paper, in harsh environments, while finite-element models are based on damage mechanics and material constitutive behavior. Sensitivity relations for geometry, materials, and architectures based on statistical models, and FEA models have been developed.
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high speed digital image correlation for transient shock reliability of electronics
Electronic Components and Technology Conference, 2007Co-Authors: Pradeep Lall, Deepti Iyengar, Sandeep Shantaram, Dhananjay Panchagade, Jeff Suhling, H SchrierAbstract:Electronics may be subjected to shock, vibration, and drop-impact during shipping, handling and during normal usage. Measurement of transient dynamic deformation of the electronics assemblies during the shock and vibration can yield significant insights in understanding the occurrence of failure modes and the development of failure envelopes. Failure-modes include solder-joint failures, pad cratering, chip-cracking, copper trace fracture, and underfill fillet failures. Previous researchers have measured the transient-dynamics of board assemblies with high-speed imaging in conjunction with high-speed image analysis for measurement of relative displacement, angle, velocity, and acceleration [Lall 2006, Che 2006]. In addition, high-speed data-acquisition systems with discrete strain gages have been used for measurements of transient strain [Lall 2004, 2005, Liang 2005] and with accelerometers for measurement of transient acceleration [Dunford 2004, Goyal 2000, Seah 2005]. Development of accurate models requires better understanding of full-field strain deformation in board assemblies. In this paper, the use of digital image correlation (DIC) with ultra high-speed imaging has been used for full-field measurement of transient strain in various board assemblies subjected to shock in various orientations. Measurements have been taken on both the package and the board side of the assemblies. Accuracy of high-speed optical measurement has been compared with that from discrete strain gages. Package architectures examined include flex Ball-Grid Arrays, tape-array Ball-Grid Arrays, and metal lead-frame packages. Explicit finite-element models have been developed and correlated with experimental data. Models developed include, smeared property models, Timoshenko-beam models, and explicit sub-models. The solder strains have been computed from the explicit finite element models for life prediction in shock.
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causes of degradation of thermal performance of Ball Grid Arrays after thermal cycling
ASME 2007 InterPACK Conference collocated with the ASME JSME 2007 Thermal Engineering Heat Transfer Summer Conference, 2007Co-Authors: Roy W Knigh, Jeff Suhling, Y Elkady, Pradeep LallAbstract:The thermal performance of Ball Grid Array packages depends upon many parameters including die size, use of thermal Balls, number of perimeter Balls, use of underfill, and printed circuit board heat spreader and thermal via design. Thermal cycling can affect the integrity of thermal paths in and around the BGA as a result of the cracking of solder Balls and delamination of the package, including at underfill interfaces. In this study, the impact of thermal cycling on the thermal performance of BGA’s was investigated and quantified. A number of test boards which included a range of the parameters cited above were experimentally examined. A baseline thermal resistance was measured for each case, which was verified with numerical thermal modeling. The boards were then subjected to thermal cycling from −40°C to 125°C. Every 250 cycles the thermal performance was measured. Packages expected to be least reliable (with large die and no underfill), showed an increase in thermal resistance after 750 thermal cycles. Further increases in thermal resistance were observed with continuous thermal cycling until solder joint failure occurred at 1250 cycles, preventing additional measurements. Finite element analysis identified critical thermal and perimeter solder Balls as the most likely sites for cracking. Boards were cross-sectioned and examined for solder joint cracks and delamination to identify the cause for the observed increases in thermal resistance. Cracking was found in the critical thermal and perimeter solder Balls.Copyright © 2007 by ASME
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degradation of thermal performance of Ball Grid Arrays after thermal cycling
Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, 2006Co-Authors: Roy W Knigh, Y Elkady, J C Suhling, Pradeep LallAbstract:The thermal performance of Ball Grid array packages depends upon many parameters including die size, use of thermal Balls, number of perimeter Balls, use of underfill, and printed circuit board heat spreader and thermal via and spreader design. Thermal cycling can affect the integrity of thermal paths in and around the BGA as a result of the cracking of solder Balls and delamination of the package, including at underfill interfaces. In this study, the impact of thermal cycling on the thermal performance of BGA's was investigated and quantified. A number of test boards which included a range of the parameters cited above were experimentally examined. A baseline thermal resistance was measured for each case, which was verified with numerical thermal modeling. The boards were then subjected to thermal cycling from -40degC to 125degC. Every 250 cycles the thermal performance was measured. Packages expected to be least reliable (with large die and no underfill), showed an increase in thermal resistance after 750 thermal cycles. Further increases in thermal resistance were observed with continuous thermal cycling until solder joint failure occurred at 1250 cycles, preventing additional measurements. The correlation between thermal cycling and thermal resistance was then analyzed using a numerical structural simulation model that predicted crack initiation in the solder joints. The first observed thermal resistance increase occurred in close proximity to the number of cycles where the finite element model predicted initiation of cracking in the thermal solder Balls
