2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)最新文献

{"title":"Evolution of the Creep Behavior for SAC305 Lead Free Solder Exposed to Various Thermal Profiles","authors":"S. Hasan, Mohammad Al Ahsan, J. Suhling, P. Lall","doi":"10.1109/iTherm54085.2022.9899502","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899502","url":null,"abstract":"In our prior study, the degradations of the effective elastic modulus (E) and ultimate tensile strength (UTS) of lead free solders were observed for samples subjected to isothermal aging and three different time dependent thermal exposure profiles. In the current paper, the evolutions of the creep behavior of SAC305 bulk solder under isothermal aging, slow thermal ramping, and slow thermal cycling exposures have been investigated. For creep testing, rectangular cross-section uniaxial test specimens were prepared using reflow solidification under a controlled temperature profile. After formation, the samples were subjected to either thermal aging, thermal ramping, or thermal cycling pre-conditioning exposures for various durations under stress-free conditions (no load). After the preconditioning was completed, creep testing was performed on the samples at room temperature.The three thermal profiles considered for preconditioning were (1) isothermal aging at 125 °C, (2) slow thermal cycling from -40 to +125 °C with 45 minutes ramps and 30 minutes dwells, (3) thermal ramping from -40 to +125 °C with 45 minutes ramps and no dwells. The thermal exposures times considered with the three profiles were 0, 1, 2, 5, and 20 days. Creep testing was performed on the exposed samples at three different stress levels (10, 12, 15 MPa). For each of the thermal profiles, the evolution (increase) of the secondary creep strain rate with exposure time was characterized. The evolutions were then compared. For long exposures, it was found that the creep rate degradation was highest for thermal cycling with a slow ramp rate. This effect was exacerbated for higher creep stress levels.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"153 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124259338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Lifetime of Through-Hole Solder Joints Considering Mounting Process and Variation","authors":"Tomohiro Tsuyuki, Qiang Yu, Y. Ohno, Akihiro Takikawa, Hisataka Fukasu, K. Shio","doi":"10.1109/iTherm54085.2022.9899688","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899688","url":null,"abstract":"In recent years, electronic devices have been widely used in various industrial fields due to the rapid development of electronics. The automotive industry is no exception, with a large number of electronic components in use. In addition, the trend toward electrification is also becoming more pronounced in large machinery such as construction and mining equipment. In these machines, large through-hole components are used, and lead-free solder is now used instead of the conventional Sn-Pb solder. The use of lead-free solder has been shown to increase the variation of solder shape at the solder joint due to the increase in mounting temperature and the difference in solder characteristics, and there is concern that this variation in shape may affect the quality of large machines.In this study, the effects of variations in the shape and material properties that can occur in solder joints on fatigue life were evaluated using CAE simulations. In addition, we focused on the shape of the solder, which is controllable among these variations, and examined the mounting process to ensure the shape.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121022500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability Assessment of Cu-Al WB under Automotive Temperatures in Presence of Ionic Contamination and Voltage Bias","authors":"P. Lall, Sungmook Jung","doi":"10.1109/iTherm54085.2022.9899620","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899620","url":null,"abstract":"A deeper understanding of the acceleration factors under operating stresses is required for high-reliability harsh environment applications. Copper wire is now being used for first-level interconnects in automotive electronics. Palladium coated copper and gold-flash palladium coated copper are two copper wire compositions that have emerged. The corrosion resistance of copper wire bonds in high-temperature environments is still unknown. The EMC used to encapsulate chips and interconnects can vary widely in formulation, including pH, porosity, diffusion rate, composition of contaminants and contaminant concentration. A predictive model that can account for ambient factors, operational circumstances, and EMC exposure is required to accurately reflect projected wirebond dependability. Different EMCs were investigated in this work in a high-temperature-current environment with temperatures ranging from 60°C to 100°C and currents ranging from 0.2A to 1A. To build a Multiphysics model, diffusion kinetics based on the Nernst-Planck Equation for chlorine ion migration were combined with the Butler-Volmer equation for corrosion kinetics. Polarization curves for copper, aluminum, and intermetallics have been measured at various pH levels and chlorine-ion concentrations.Measurements of polarization curves were used to extract Tafel parameters.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124873979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance of Component Interconnection Methods on Direct Write Additive Silver Circuits","authors":"P. Lall, Jinesh Narangaparambil, Scott Miller","doi":"10.1109/iTherm54085.2022.9899646","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899646","url":null,"abstract":"Flexible electronics has gained increased traction in a number of applications for closer integration of form and function. Further research in 3D printing is needed to bridge the gap between connecting SMD components on additively printed circuits and replacing conventional rigid boards due to the increased need for FHE. Different research and technology to build interconnections between printed traces and surface mounting devices are presently being studied (SMD). It is crucial to develop the way passive components are connected to a flexible substrate and to create a reliable connection to replace traditional rigid boards with flexible electronics. In FHE, there is quite some literature available with printed silver traces and various component attachment materials. With the growing demand for silver in Flexible Hybrid Electronics (FHE), it is critical to comprehend the effect of the binding material on the performance of the connected component. To understand the behavior of the binding materials, we employed several binding materials such as low-temperature solder (LTS) and electrically conductive adhesive (ECA) in conjunction with various active and passive components in this study. We tested the components before and after attachment to have a better knowledge of the component attachment performance characteristics. We also examine the intermetallic development at the cross-section using a scanning electron microscope (SEM) with Energy Dispersive X-ray analysis (EDX). The Shear Test (Mechanical Property) of the attached components has also been presented for the various applications to establish a reliable application-based material selection. We have used OrCAD software to build and analyze an inverting OpAmp circuit to simulate applications.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123569719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of Interface Reliability of PCB-UF Interface in FCBGAs under Sustained High Temperature Operation in Automotive Underhood Environments","authors":"P. Lall, Padmanava Choudhury","doi":"10.1109/iTherm54085.2022.9899517","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899517","url":null,"abstract":"Electronics are increasingly being employed in automobile applications for safety-critical tasks to allow sophisticated driver-assist systems (ADAS). Lane departure warning systems, collision avoidance systems, driver alertness monitoring, park and drive assist systems, adaptive cruise control, and semi-autonomous navigation are just a few examples. The majority of the electronics are placed under the hood, where they may be exposed to temperatures in the range of 100-200°C for up to 10-years over the vehicle's lifetime. FCBGAs (Flip-Chip Ball Grid Arrays) are being used to provide safety-critical tasks in automobile underhood electronics. Underfills needed to reinforce flip-chip interconnects in FCBGAs need to operate reliably under sustained high temperature operation. Under extreme temperature conditions, the underfill-to-substrate interface is one of the most common failure sites, and it is generally a prelude to flip-chip junction failure. Understanding the damage development of the underfill-to-substrate interface as a function of running duration and operating temperature is required to assess the dependability in the end application. In this study, the Substrate-UF interface was exposed to high temperature and the interfacial fracture toughness quantified. A three-point and four-point composite beam specimen of Substrate/Underfill was fabricated to study the interface and thermally aged for periods of 10 days, 30 days, 60 days, 120 days, 360 days at temperatures ranging from 100°C to 150°C. Quasi-static bending was used to observe and determine interfacial delamination of the sample specimen. A 2D-Digital Image Correlation (DIC) method was also employed to understand the Crack tip opening displacement (CTOD), crack initiation and the fracture toughness, CTOD were compared with the aging schedule and temperature. The CZM parameter developed from the image correlation and critical load is used to make a damage model in Abaqus to rank the underfills and to validate the experimental procedure. The model is also predict the failure rather than conduct the expensive experimental to get the performance characteristics of the underfills","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123767694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Air-Cooled Closed Loop Thermosyphon Cooling System Experimental Campaign: Effects of Working Fluid, Heat Load and Air Flow Rate","authors":"Enzo M. Minazzo, Gautier Rouaze, J. Marcinichen, J. R. Thome, L. Zhang","doi":"10.1109/iTherm54085.2022.9899565","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899565","url":null,"abstract":"This study presents the experimental results of a test campaign performed on a closed loop thermosyphon having a footprint cooling area of 50 mm x 50 mm designed specifically for cooling of high heat flux microprocessors for 2U servers by JJ Cooling Innovation and Novark Technologies. Importantly, the cooling load to fan power load performance ratios determined by measuring the fan’s consumption showed ratios up to 60-to-1 were obtained using this compact thermosyphon cooling technology. In particular, the effects of working fluid charge and type, heat load and air flow rate have been investigated. In the first set of tests, the main parameter of interest was the filling ratio. The results show that for the three low global warming potential refrigerants R1233zd(E), R1234ze(E) and R1336mzz(Z), the thermal resistance increases with the filling ratio. To ensure safe operation, the optimal filling ratio was chosen as 50% for R1233zd(E), 42% for R1234ze(E) and 50% for R1336mzz(Z). A second set of tests was performed at these optimal filling ratios at different heat loads (from 50 W to 750 W) and air volumetric flow rates (50, 100 and 150 CFM). For the range of heat loads tested, when the heat load was increased, the thermal resistance decreased until a lower plateau limit value was reached. The smallest thermal resistance was reached with R1234ze(E) at 750 W and 150 CFM, equal to 0.065 K/W. Finally, to more closely emulate a real CPU cooling application, the heated copper block used in the previous tests was replaced by a power resistor in a last set of tests but only for refrigerant R1233zd(E). Furthermore, no temperature overshoots were observed for cold startup tests; however, the maximal heat load without reaching dry out was 250 W lower than with the copper block due to non-uniform heat generation of this type of heater.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125690489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Full-field pump-probe thermoreflectance imaging for characterization of thin films and 3D integrated circuits","authors":"S. Alajlouni, K. Maize, A. Shakouri","doi":"10.1109/iTherm54085.2022.9899513","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899513","url":null,"abstract":"We evaluate optical pump-probe imaging where laser heating and subsequent non-contact full-field thermoreflectance characterization is used to study thin film materials and 3D integrated circuit chips. The diameter of the heated region can range from one micron up to millimeters or centimeters. The shape of the surface or interface thermoreflectance profile is then captured with 50 ns time-resolution using mega-pixel lock-in camera. By combining the measured thermal surface profile with finite-element modeling, we demonstrate the ability to extract the thermal conductivity of thin films on various substrates. With the proper choice of pump and probe wavelengths, the potential of the technique as a general characterization tool is evaluated. There is a lot of interest in structural integrity and failure-analysis of complex chips during manufacturing. Heat sinking in 3D chips is often a key challenge. The sensitivity of the full-field thermal imaging technique to study the quality of buried (below the surface) layers or contacts in 3D chips is quantified.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"202 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116565650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Optimal Solution of Reflow Oven Recipe based on Physics-guided Machine Learning Model","authors":"Yangyang Lai, K. Pan, J. Ha, Chongyang Cai, Junbo Yang, Pengcheng Yin, Jiefeng Xu, Seungbae Park","doi":"10.1109/iTherm54085.2022.9899644","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899644","url":null,"abstract":"This paper presents a physics-guided machine learning model to provide the optimal reflow recipe for a 7-zone oven. The numerical method based on the computational fluid dynamics (CFD) simulation was used to predict reflow profiles of a BGA package. After validating the CFD model with the measurement results, an automated system was programmed to collect profiles subjected to 81 sets of boundary conditions (reflow recipe). A machine learning model trained by 81 sets of input data was employed to predict profiles subjected to 148,176 sets boundary conditions rapidly. The peak temperature and time above liquidous of output profiles were extracted to quantify the performance of the corresponding boundary conditions. The boundary condition with the best reflow performance was regarded as the optimal recipe.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122190858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Component Attachment to Inkjet Additive Printed Circuits to Achieve Flexible Signal Filters using Silver and Copper Nanoparticle Metal Inks","authors":"P. Lall, Kartik Goyal, Scott Miller","doi":"10.1109/iTherm54085.2022.9899673","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899673","url":null,"abstract":"In this paper, process-performance interactions have been studied for Inkjet printed circuits and attachment of surface mount components. Electrical and mechanical properties are quantified along with demonstration of functional electronic circuits with surface mount components consisting of frequency filters and op-amps. While additive printing of circuits has been demonstrated in prior studies, the attachment of surface mount components using robust process recipes has been an elusive goal. Inkjet processes have the ability of high throughput of electrical print processes owing to the usage multiple nozzles and potential for high print speeds. There is need for process recipes and understanding of the print process parameters on the component attachment reliability and performance. Two most commonly used metals, silver and copper, both having their own merits, are utilized. Process-property interactions for both the material against their post-print treatments are characterized. For the silver material, thermal sintering at 130°C for 20 mins yields the resistivity of 7.42 μΩ-cm (4.6 times the bulk silver), while for copper, resistivity is found to be 5.5 times the bulk copper. In terms of shear load to failure, both the materials came fairly close of 15-20gF. From the defined print process parameters, applications are demonstrated by printing high pass filter, low pass filter, and a non-inverting op-amp. The characterization against frequency for the electronic circuits are validated by the PSpice simulations as well. The authors' aim to develop these circuits is to show the capability of Inkjet platform to successfully attach surface mount components on printed pads and establish Inkjet technology to be a viable alternate to manufacture traditional electronic circuits.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128439569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Thermal Mechanical Solutions on Solder Joint Reliability of Bare-Die BGA with Substrate Stiffener","authors":"P. Geng","doi":"10.1109/iTherm54085.2022.9899650","DOIUrl":"https://doi.org/10.1109/iTherm54085.2022.9899650","url":null,"abstract":"BGA package stiffener on bare-die substrate has become more prevalent to mitigate ball grid array (BGA) substrate warpage during the assembly process. The adoption of this technology for large-size BGAs may post challenges to thermal mechanical solutions (mechanical retention, heatsink, etc.) on motherboards and cards, especially the Peripheral Component Interconnect express (PCIe) cards or Open Compute Project (OCP) Accelerator Module (OAM) cards.In this work, temperature cycle test of an OAM card with a typical thermal mechanical design shows BGA solder joint cracks at early cycles. Failure location starts at BGA corners and spreads to edges with increasing cycles. A structural system model is established to include both the BGA on the card and the thermal mechanical solution. The effects of temperature change, thermal interface material (TIM) load, and thermal mechanical retention are investigated. Root-cause of the solder joint temperature cycling failure is identified through the finite element analysis. The interaction of the substrate stiffener and the thermal mechanical solution is shown as the primary factor to the solder joint temperature cycle failure. It can generate significantly high solder joint stress at BGA corners during temperature cycling. The finite element analysis shows that increasing stiffener thickness increases solder joint axial force during temperature cycle tests. It also shows that heatsink compressive TIM load effect is secondary.In conclusion, large-size BGA thermal mechanical design needs to adapt and accommodate to bare-die BGA with substrate stiffener, while substrate stiffener thickness needs to be addressed for thermal mechanical solutions during package design.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124576359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}