2017 18th International Conference on Electronic Packaging Technology (ICEPT)最新文献

{"title":"Assessment of solder paste technology limitation at miniaturization for SIP and SMT application","authors":"J. Keck, N. Lee","doi":"10.1109/IMPACT.2017.8255961","DOIUrl":"https://doi.org/10.1109/IMPACT.2017.8255961","url":null,"abstract":"For SiP or SMT assembly process, solder paste has been the choice of primary soldering material. In the meantime, miniaturization has been the trend of electronic industry. While the size of components, pads, stencil thickness, aperture, pitch, and solder powder has been shrinking continuously so far, it is about time to ask whether the solder paste technology is able to support this trend forever. In this study, solder powder oxygen content was observed to increase linearly with increasing powder surface area up to Type 5. Beyond Type 5, it is getting difficult to maintain oxide thickness. Beyond Type 8, the oxide thickness always higher than Type 5 or coarser. The flux burn-off rate increased linearly with decreasing flux size plotted in log scale. However, for solder paste, the paste residue showed a sharp drop initially with decreasing flux quantity, then levelled off at 3 mg flux (∼30 mg paste), and maintained at around 30% residue through the remaining range down to 0.3 mg flux (∼3 mg paste). The constant residue level at small sample size was attributed to the surface adsorption phenomenon, or “Flux Shell” phenomenon, where a layer of flux was strongly adsorbed on the solder powder surface. For solder paste, the flux workload increased rapidly with decreasing powder size. The flux capacity needed in removing oxide was derived as volume fraction of COOH functional group in flux residue, with 10% maximum being set as a guideline for no-clean applications. Type 8 paste may be the limit of SiP or SMT printable no-clean solder paste due to corrosivity consideration. Oxygen barrier and alloy dopants may expand the miniaturization potential. When reviewing the brittleness of solder joint formed, Type 6 may be the limit of fine pitch applications. Beyond that, the joints may be too brittle to be reliable, unless underfill is applied.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133425938","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":"Novel solder ally with wide service temperature capability for automotive applications","authors":"J. Geng, HongWen Zhang, Francis Mutuku, N. Lee","doi":"10.1109/IMPACT.2017.8255963","DOIUrl":"https://doi.org/10.1109/IMPACT.2017.8255963","url":null,"abstract":"A novel lead-free solder alloy 90.6Sn3.2Ag0.7Cu5.5Sb, designated as Indalloy276, was developed targeting for high reliability with a wide service temperature capability. The alloy exhibited a melting temperature range of 223 to 232°C, reflowable at profile with peak temperature 245°C and 255C, with ambient temperature Yield stress 60MPa, UTS 77 MPa, and ductility 28%, and a higher stress than both SAC305 and Innolot, the latter two alloys were used as controls. When tested at 140°C and 165°C, the die shear stress was comparable with Innolot but higher than SAC305, and the ductility was higher than both Innolot and SAC305, with Innolot exhibited distinct brittle behavior. When aged at 125°C and 175°C, the die shear strength was comparable or higher than both controls. When pretreated with a harsh condition, TST −55°C/155°C for 3000 cycles, the die shear strength of 276 was 8 times of that of Innolot and SAC305. When pre-conditioned at TCT (−40°C/175°C) for 3000 cycles, the die shear strength of 276 was 11 to 20 times of Innolot and SAC305, depending on the flux type used. For SMT assembled BGA solder joints with both ball and paste using the same alloy, 276 showed higher Eta value than Innolot and SAC305 when tested at TCT with −55°C/125°C and − 40°C/150°C. For 1% failure, 276 was 2 to 3 times higher in cycling life than Innolot, mainly due to the Beta value of 276 being much higher than Innolot. SAC305 performed the poorest in these two tests. Both 276 and Innolot are alloys based on SnAgCu, but reinforced with precipitate hardening and solution hardening, with the use of additives including Sb, Ni, and Bi. 276 exhibited a finer microstructure with less particles dispersed, while Innolot exhibited more particles with some blocky Ag3Sn plates or rods. 276 is rigid and ductile, while Innolot is rigid but brittle, Under the harsh test condition where ΔT was high, the dimension mismatch between parts and substrate became very significant due to CTE mismatch. This significant dimension mismatch would cause a brittle joint to crack quickly, as seen on Innolot. The challenge was more tolerable for a ductile joint, as shown by 276. Accordingly 276 showed a much better reliability than Innolot under harsh condition, including high testing temperature and large ΔT. Overall, to achieve high reliability under a wide service temperature environment, a balanced ductility and rigidity for solder alloy is critical for success.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122404682","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":"Modelling the impact of conformal coating penetration on QFN reliability","authors":"C. Yin, S. Stoyanov, C. Bailey, P. Stewart","doi":"10.1109/ICEPT.2017.8046616","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046616","url":null,"abstract":"The impact of conformal coating penetration on the solder joints' thermal fatigue reliability in QFNs was studied using computational modeling techniques. 3D finite element models were developed with consideration of realistic solder joint shape and the actual coating profile. Thermal mechanical simulations were carried out for three cycles under accelerated thermal test conditions of −25 to 100°C, 10 minutes ramp and 10 minutes dwell. The inelastic strain energy density accumulated over one temperature cycle was used as an indicator for solder damage in the QFNs under the applied thermal cycling load. The impact of coating penetration level on the solder damage in QFNs was investigated for two types of coatings with different properties. The results show that coating penetrated underneath the package has significant impact on the solder joint damage in QFNs and the level of this impact depends on the coating properties and penetration level. When coating penetration level decreases, damage in the solder joint does not always decrease. In order to prevent coating penetration underneath the package, an edgebond adhesive was applied on the edge of the QFN assemblies prior to the application of the conformal coating. The modelling results show that using edgebond adhesive can reduce the solder joint damage in the investigated QFNs and thus improve their thermal fatigue reliability. When edgebond adhesive is used, the impact of conformal coating on the reliability of solder joints in QFNs is significantly reduced.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128764567","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":"Electro-thermal modelling of multichip power modules for high power converter application","authors":"M. Shahjalal, Hua Lu, C. Bailey","doi":"10.1109/ICEPT.2017.8046599","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046599","url":null,"abstract":"In a compact power electronics systems such as converters, thermal interaction between components is inevitable. Traditional RC lumped modelling method does not take that into account and this would cause inaccuracy in the predicted temperature in the components of the systems. In this work, numerical simulation have been used to obtain detailed temperature distribution in power devices and the parameters for a Foster network behavior thermal model are extracted so that the thermal interaction can be accounted for and the model can be used to predict temperatures at all critical layers of the components. An ad-hoc conventional three-phase voltage source inverter (DC to AC converter) with a rating of 7.8 KW has been studied in this work as an example of the application of the proposed framework. The key component in the converter is a 75A/1200V rated IGBT module. A power electronics circuit simulator is used to predict the power losses in the IGBT module and a Finite Element Analysis software is used to obtain the transient temperature profile in the module and the behaviour thermal model parameters are extracted using curve-fit approach. The resulting combined electro-thermal model is analysed using the circuit simulator again to obtain the temperature for various loading conditions. The results show that the proposed method can significantly improve the accuracy of predicted temperatures in the IGBT modules.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122884192","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 mechanism of Al contents (0–0.09 wt%) on the wettability and interfacial intermetallic compounds growth of Zn-25Sn/Cu","authors":"Kwang-Lung Lin, Xiaodong Niu","doi":"10.1109/ICEPT.2017.8046412","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046412","url":null,"abstract":"The wettability of the solders Zn-25Sn-XAl (x=0–0.09wt%) was investigated by dipping method. The interfaces between solders and Cu substrate were investigated by scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and energy dispersive spectroscopy (EDS) equipped in transmission elctron microscopy (TEM). It was found that the addtion of Al enhances the wettability of the solders on Cu. The three layers (Cu,Al)Zn, (Cu,Al)5Zn8 and (Cu,Al)Zn5 were found at the interfaces between Cu substrate and solders. The thickness of intermetallic compounds layers increased with Al additions. The higher Al addition, the higher Al intetnsity was detected in the intermetallic compounds layer. The Al addition exhibits two stages behaivor on both wetting time and interfacial intermetallic growth.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133597709","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":"Process emulation for predicting die shift and wafer warpage in wafer reconstitution","authors":"C.-Y. Yang, Y.C. Liu, K.‐S. Chen, T. Yang, Y.-C. Wang, S. Lee","doi":"10.1109/ICEPT.2017.8046441","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046441","url":null,"abstract":"Wafer reconstitution is a vital process for serving as a buffer to decouple the processing developments between IC fabrication and electronics packaging. By this approach, the IC packaging is then independent from the chip processing. However, such a process brings numerous mechanical loadings during molding and curing phases. Without carefully planning, failures such as die-shifting and excessive wafer warpages are frequently reported and it induces problems for subsequent processing. In this work, it is desired to examine the key factor of die-shift and wafer warpage by performing both fluidic mold flow and solid thermo-mechanical analyses, as well as essential material characterizations. Preliminarily, the die-shift problem is deduced as interaction of fluid load, thermal expansion, shrinkage of molding compound and viscoelastic effect. To have a deeper insight, simplified fluid model and finite element analyses have been constructed to mimic the entire Recon process. For mold flow analysis, a simplified 1-D viscous flow analytical model is adapted. It aims to find the relationship between the molding parameters and the achieved velocity and pressure fields for calculating the possible drag and shear forces acting on dies for causing shift. On the other hand, after molding, the stress and deformation of the entire curing process is then performed by finite element method. The possible die shift and final warpage are then examined step by step to evaluate the contribution from each step and even each processing parameter. Both simplified 2-D axisymmetric and 3D models are performed and analyzed. The preliminary analysis results indicate that the thermal stress during curing is the current dominating factor. Related parameters such as the properties of compounds and carriers and the process parameters such as the curing temperature and duration could be the major controlling factors.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127389130","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":"Low temperature co-fired Sn-Ca co-substituted Y3Fe5−2xSnxCaxO12 ferrites for microwave devices application","authors":"Jie Li, Tianhui Qiu, Dandan Wen, Yingli Liu, Y. Jing, Weixun Huang","doi":"10.1109/ICEPT.2017.8046420","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046420","url":null,"abstract":"To meet the requirements of improving performances and realizing miniaturization and integration for microwave devices, low temperature co-fired ceramic (LTCC) technology emerged and has been widely investigated. In present work, with 2.5wt% BBSZ additive, low temperature co-fired Sn4+ and Ca2+ ions co-doped Y3Fe5−2xSnxCaxO12 (x=0.0∼0.8 with 0.2 step) ferrite materials were synthesized using solid state reaction process. The structural characterizations such as X-ray diffraction, scanning electron microscope and bulk density have been carried out. Single phase YIG can be obtained with 2.5wt% BBSZ sintered at 1050 °C. The bulk density of samples decreased with Sn-Ca substitution increasing. The room temperature hysteresis loops, dielectric loss and FMR linewidth were measured. Saturation magnetization (Ms) and coercivity (Hc) extracted from the loops. With substitute content increasing, the saturation magnetization decreased (from 50.25 emu/g to 31.96 emu/g) due to weak magnetism of Sn-Ca. Coercivity decreased first from 40.14 Oe to 24.14 Oe, and then increased to 25.34 Oe. When x=0.4, the minimum FMR linewidth value was 31 Oe. Meanwhile, the value of tanδε was about 0.033∼0.047 at high frequency (10 MHz∼100 MHz). These garnets have excellent magnetic properties and low dielectric loss which made a promising material for microwave devices can be used.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114971277","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":"Impact of tensile strength on thermal fatigue properties and failure modes of Sn-Ag-Cu-Ni solder joints","authors":"Xiaodong Liu, Jing Shang, Jianxia Hao, A. Hu, Liming Gao, Ming Li","doi":"10.1109/ICEPT.2017.8046608","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046608","url":null,"abstract":"With the requirements of higher board level reliability, researchers gradually turned attention to complex composition solders like Sn-Ag-Cu-Ni-Bi solders. This quinary system solder has lower melting point and higher tensile strength than traditional Sn-Ag-Cu solder, which may good for the reliability. In this research, the effects of tensile strength on thermal fatigue properties of Sn-2Ag-0.5Cu-0.05Ni and Sn-4Ag-0.5Cu-0.05Ni-3Bi solders were studied. After 1000 thermal cycles, SEM observation and nanoindentation test were used to characterize the failure mechanism and mechanical properties. The results demonstrated that Sn-4Ag-0.5Cu-0.05Ni-3Bi solder joints had better thermal fatigue properties than Sn-2Ag-0.5Cu-0.05Ni solder joints. The tensile strength of Sn-4Ag-0.5Cu-0.05Ni-3Bi solder was higher, so it can endure more stress and have less deformation in thermal cycling. And with the diffusion of Cu/Sn couples, the modulus and hardness of Sn-2Ag-0.5Cu-0.05Ni solder near the IMC interface decreased a lot, which promoted the crack formation and finally caused the fracture at the bulk solder. While for Sn-4Ag-0.5Cu-0.05Ni-3Bi solder, it didn't decrease too much due to the Bi concentration effect at the interface, which led to the crack formation in IMC. Hence, solders with higher tensile strength, like Sn-4Ag-0.5Cu-0.05Ni-3Bi solders, may have better thermal fatigue properties.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115456045","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":"Microstructure and mechanical properties of Au60AgCu joints brazed with Sn63Pb solder","authors":"Xiuli Wang, Xinhua Wang","doi":"10.1109/icept.2017.8046440","DOIUrl":"https://doi.org/10.1109/icept.2017.8046440","url":null,"abstract":"The joints of Au60AgCu alloy to silver and copper plated wire were obtained by using Sn63Pb solder, and the microstructure and mechanical properties of the brazing joints were investigated. The shear strength and the reliability of joints after the high and low temperature test were evaluated in this study.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125150155","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 Cu@SiO2 core-shell nanoparticles filled polyvinylidene fluoride nanocomposites film: Fabrication, characterization and dielectric property analysis","authors":"Jianying Du, Wenhu Yang, W. Liao, Z. Xiong, Feng Li, Shuhui Yu, R. Sun","doi":"10.1109/ICEPT.2017.8046734","DOIUrl":"https://doi.org/10.1109/ICEPT.2017.8046734","url":null,"abstract":"In this paper, the Cu@SiO2 core-shell particles were synthesized using a simple method and well characterized with XRD and SEM techniques. The results of TEM show that a thickness of 15–20 nm SiO2 shell were uniformly coated on the surface of copper particles. The dielectric properties of the PVDF composites filled with Cu@SiO2 particles were measured and analyzed. The results show that the dielectric constant of PVDF flexible composites film increases with increasing filler content. Moreover, the 19vol% composite film presents obvious nonlinear I–V properties, which indicates that this film can be used for ESD protection circuit.","PeriodicalId":386197,"journal":{"name":"2017 18th International Conference on Electronic Packaging Technology (ICEPT)","volume":"2011 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125825255","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}