IEEE Transactions on Electronics Packaging Manufacturing最新文献

{"title":"Comparison of Printed Circuit Board Property Variations in Response to Simulated Lead-Free Soldering","authors":"B. Sood, R. Sanapala, D. Das, M. Pecht, C. Huang, M. Tsai","doi":"10.1109/TEPM.2010.2042453","DOIUrl":"https://doi.org/10.1109/TEPM.2010.2042453","url":null,"abstract":"Use of lead-free solders such as Sn/Ag/Cu results in exposure of printed circuit boards to higher temperatures during assembly compared with eutectic tin-lead solder. If the thermo-mechanical and electrical properties of the laminate materials get affected by exposure to this higher temperature, that may impact the performance and reliability of the circuit board. Variations, if any, in laminate material properties before and after board assembly should be considered in the selection of appropriate laminates. The board and system designers need to be cognizant of such variations and account for them during laminate selection for an application. This paper presents guidelines for laminate selection along with the process used to derive the guidelines. The process includes measurement of key material properties (glass transition temperature, coefficient of thermal expansion, decomposition temperature, time-to-delamination, water absorption, flammability, dielectric constant, and dissipation factor), and their responses to lead-free soldering assembly conditions. A range of commercially available FR-4 printed circuit board laminate materials, classified on the basis of glass transition temperature (high, medium, and low), curing agents (dicyandiamide and phenolic), flame retardants (halogenated and halogen-free), and the presence of fillers, are included in the measurements. The measurements are conducted in accordance with IPC-TM-650 test methods before and after exposure to multiple lead-free soldering profiles. The extent of variations in the properties due to lead-free soldering exposures are reported and analyzed as a function of classification parameters. The causes behind the variations in material properties are investigated by Fourier transform infrared spectroscopy analysis and a conjunctional property analysis. This study also suggests that the preconditioning steps specified in the IPC test methods should address the initial moisture content of the laminate test samples in material property measurement tests, otherwise significant errors can be introduced.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"1 1","pages":"98-111"},"PeriodicalIF":0.0,"publicationDate":"2010-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77756876","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 Grain Size on Pressure-Induced Tin Whisker Formation","authors":"T. Shibutani","doi":"10.1109/TEPM.2010.2042060","DOIUrl":"https://doi.org/10.1109/TEPM.2010.2042060","url":null,"abstract":"This paper discusses the effect of grain size on pressure-induced tin whisker formation. Since a pressure has to overcome the increase in surface energy involved with tin whisker growth, a threshold stress for tin whisker growth exists. Based on traditional nucleation theory, the threshold stress is inversely proportional to the radius of the whisker. For the verification of the proposed theory, nanoindentation tests were carried out on three kinds of finishes with different grain sizes; tin-copper, bright tin, and matte tin. Whiskers and nodules were formed at the contact edge as the applied load increases up to the critical value related to grain size. The finite-element analysis revealed that high pressure concentrates near the contact edge on the tin-copper finish. The value of pressure to whisker formation is up to 40 MPa. This value agrees with the estimation from the proposed theory with a whisker radius of 0.1 μ m. Based on the proposed theory, the difference between whiskers and hillocks can be explained.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"11 1","pages":"177-182"},"PeriodicalIF":0.0,"publicationDate":"2010-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89173518","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":"Understanding the Correlation Between Intermetallic Growth, Stress Evolution, and Sn Whisker Nucleation","authors":"N. Jadhav, E. Buchovecky, L. Reinbold, S. Kumar, A. Bower, E. Chason","doi":"10.1109/TEPM.2010.2043847","DOIUrl":"https://doi.org/10.1109/TEPM.2010.2043847","url":null,"abstract":"Stress due to intermetallic (IMC) growth is generally accepted as the driving force for Sn whisker formation, but there are still many unanswered questions regarding the development of stress and how it relates to the growth of whiskers. We have made simultaneous measurements of the evolution of stress, IMC volume, and whisker density on samples of different thicknesses to address the underlying mechanisms of whisker formation. Finite-element simulations are used to study the stress evolution due to IMC growth with various stress relaxation mechanisms: plastic deformation coupled with grain boundary diffusion is found to explain observed stress levels, even in the absence of whisker growth. A model of whisker growth suggests that the average steady-state stress is determined primarily by relaxation processes (dislocation- and diffusion-mediated) and that whisker growth is not the primary stress relaxation mechanism. Implications of our results for whisker mitigation strategies are discussed.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"53 1","pages":"183-192"},"PeriodicalIF":0.0,"publicationDate":"2010-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74271445","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":"A Study of Crack Propagation in Pb-Free Solder Joints","authors":"J. Caers, X.J. Zhao, E. Wong, S. Seah, C. Selvanayagam, W. V. van Driel, N. Owens, M. Leoni, L. C. Tan, P. Eu, Y. Lai, Chang-Lin Yeh","doi":"10.1109/TEPM.2009.2039710","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2039710","url":null,"abstract":"The higher stiffness of Pb-free SAC solders makes Pb-free assemblies more sensitive to drop impact. In order to be able to optimize the drop test performance, it is necessary to have better insight into the crack propagation in the Pb-free solder joints. This study combines crack-front mapping using the dye and pry method and electrical FE simulation to establish a relation between DC electrical resistance and cracked area, and hence monitor the initiation and propagation of cracks in individual solder joints as the PCB assemblies are subjected to JEDEC type mechanical shock and high speed cyclic bending. The carrier in the study is a ball grid array (BGA), a critical component family for drop impact. Combinations of solder alloys and pad finishes, SnPb on organic solderable preservative (OSP), SAC305 on electroless nickel/immersion gold (ENIG), SAC101 on OSP, and SAC101(d) on ENIG are studied regarding the failure mode and crack propagation. This paper demonstrates that, for the large majority of Pb-free solder joints, there is a negligible initiation period; cracks can start forming at the first PCB bending cycle. The presence of large cracks, especially at both sides can increase the compliance of the joint and slow down crack growth. Even if large cracks are present, the resistance increase is less than 1 m¿ per interconnect, which is far from the 100 ¿ that is often taken as a failure criterion. Brittle joints as found with SAC305 on ENIG have erratic propagation rates while ductile joints are much more predictable. Therefore, the way to optimize the drop test performance of a Pb-free BGA assembly is to prolong the crack propagation within the ductile bulk solder material.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"18 1","pages":"84-90"},"PeriodicalIF":0.0,"publicationDate":"2010-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90699724","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":"Online Postweld Shift Measurement of Butterfly-Type Laser Module Employing High-Resolution Capacitance Displacement Measurement System","authors":"Yu-Da Liu, M. Sheen, Y. Hsu, H. Hsu, Y. Tsai, W. Cheng","doi":"10.1109/TEPM.2009.2039754","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2039754","url":null,"abstract":"A quantitative postweld shift (PWS) correction employing a high-resolution capacitance displacement measurement system (CDMS) in laser-welded butterfly-type laser module package is demonstrated. The CDMS has a 25.4-nm resolution and enables precise online measurement of the PWS in both the horizontal and vertical directions. By applying a mechanical adjustment to compensate for the magnitude and direction of the PWS measured online by the CDMS, the results show that the fiber tip can be realigned back closer to the original optimum coupling positions. A relative coupling efficiency of the laser modules can be regained up to an average of 88% by using the CDMS. In comparison with the previous studies on the quantitative PWS compensation in laser-welded butterfly-type laser module packages, the advantages of using this novel CDMS are the high-resolution and the online measurements of the PWS in laser-welded butterfly-type laser module packages. Through an in-depth study on the precise online measurement of the PWS employing high-resolution CDMS, it is now possible to fabricate high-yield butterfly-type laser modules for use in lightwave transmission systems and utilization of many other high-yield and low-cost laser-welded photonics module packages.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"1 1","pages":"91-97"},"PeriodicalIF":0.0,"publicationDate":"2010-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85009325","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":"Measuring Manufacturing Yield for Gold Bumping Processes Under Dynamic Variance Change","authors":"W. Pearn, Y. Tai, W.L. Chiang","doi":"10.1109/TEPM.2009.2038994","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2038994","url":null,"abstract":"Recently, the technology of gold bumping has become more popular due to high demand for LCD driver ICs. The requirement of higher resolution application, however, will increase the difficulties for manufacturing the gold bumps due to their high pin counts. For gold bumping processes, bump height is one of the key parameters to control process yield. In reality, some inevitable process variations and shifts regarding the bump height may occur under dynamic manufacturing environment. Conventionally, manufacturing yield for gold bumping processes is calculated under the assumption that the processes are stable. In practice, however, the processes are dynamic, particularly, in the operation of Au-plating in gold bumping factories. To obtain accurate measure of the manufacturing yield, we present a capability index method for manufacturing yield calculation with dynamic variance change considerations. Using this method, the magnitude of the undetected variance change, which is function of the detection power of the S 2 chart, is incorporated into the adjusted calculation of manufacturing yield. The detection powers of the S 2 chart under various subgroup sizes are tabulated. For illustration purposes, a real application in a gold bumping factory which is located in the Science-based Industrial Park in Hsinchu, Taiwan, is presented.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"1 1","pages":"77-83"},"PeriodicalIF":0.0,"publicationDate":"2010-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89161723","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":"Ray-Tracing Studies on Optical Periscopes Suitable for Out-of-Plane Interconnects on Optical Backplanes","authors":"S. Uhlig","doi":"10.1109/TEPM.2009.2038062","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2038062","url":null,"abstract":"Micro-periscopes suitable for out-of-plane optical interconnects in multi-mode optical waveguide systems are investigated by ray-tracing simulations. Various parameter setups, e.g., curved mirrors and add-on lens systems, were investigated by applying methods of statistical design of experiments, such as fractional factorial design and surface response analysis. The optimum optical net-loss was found to be in the order of magnitude of 3.5 dB for such periscopes. Furthermore, misplacement analysis' for these periscopes were performed in respect to a connection line of two tentative waveguides. The position of a -3 dB loss-line, was found to be as close as 35 ¿m and as far as 70 ¿m parallel to the ideal connection line of the waveguides.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"95 1","pages":"55-64"},"PeriodicalIF":0.0,"publicationDate":"2010-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84384412","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":"Ti/Au Die Backside Metallization for Flip Chip Heat Spreader Attachment","authors":"Yuquan Li, R.W. Johnson, R. Zhang, P. Henson, P. Thompson, T. Hooghan, J. Libres","doi":"10.1109/TEPM.2009.2037012","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2037012","url":null,"abstract":"In this paper, a heat spreader attachment with indium solder for high-power flip chip-in-package application was investigated. The Cu heat spreader was metallized with Ni/Au and the flip chip die backside metallization was Ti/Au. A low voiding attachment process was achieved with vacuum soldering. The Au thin film was converted into AuIn2 completely after initial soldering, but no intermetallic compund (IMC) formation between Ti and In was observed. The attachment had good mechanical strength as measured by shear testing. The shear strength was not degraded significantly after multiple lead free solder reflows or with thermal aging at 120°C. For thermal shock cycle test (-40°C to 85°C), die with Ti/Au (2000 A¿ of Au) metallization had early partial delamination. The effect of Au thickness on mechanical strength was further evaluated. Assemblies (Cu on Si) with Ti/Au (2000 A¿) die had lower shear strength compared with Ti/Au (3000 A¿) and Ti/Au (4000 A¿ ) die. The pull strength (Si on Si) increased with increasing gold thickness. Thermal shock testing (-40°C to 85°C) for assemblies with Ti/Au 3000 A¿ along with Ti/Ni/Au (control) did not show early delamination and had similar performance after 2000 cycles.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"40 1","pages":"44-54"},"PeriodicalIF":0.0,"publicationDate":"2010-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73293598","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":"A Novel Nitric Acid Etchant and Its Application in Manufacturing Fine Lines for PCBs","authors":"Guoyun Zhou, Wei‐dong He, S. Wang, Y. Mo, K. Hu, B. He","doi":"10.1109/TEPM.2009.2034534","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2034534","url":null,"abstract":"We have developed a new etching solution for the printed circuit board industry. The primary oxidant of the solution is nitric acid, which reacts with copper coating on the substrate. The other components of the solution are sulfuric acid and additive, which are used to control etching reaction rate and solution's characteristics. The optimum parameters for the concentrations of nitric acid, sulfuric acid, additive, and the operating temperature were obtained through orthogonal experiment with stagnant etching method. The parameters were then verified by the spray etching experiment in the industrial production line. Then, there are a series of tests, carried out by metallographic slicing tester and scanning electron microscopy to evaluate the quality of copper conductive lines in stagnant and spray etching experiments. compared with conventional cupric chloride etchant, the testing results showed that the nitric acid etchant can manufacture fine lines with lower undercut, better wall sides, with higher etching rate, as well as being more friendly to the environment How the addition of H2SO4 influences etching rate and etching mechanism of nitric acid etchant is also discussed.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"177 1","pages":"25-30"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76723260","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 Bond Strength of Au/Si Eutectic Bonding Studied by IR Microscope","authors":"E. Jing, B. Xiong, Yuelin Wang","doi":"10.1109/TEPM.2009.2035307","DOIUrl":"https://doi.org/10.1109/TEPM.2009.2035307","url":null,"abstract":"The interface of Au/Si(100) eutectic bonding was investigated by infrared (IR) microscope and related to the bond strength. A strong relationship between the IR images and the bond strengths was found. Bond strength test showed that a strong bond has many square black spots in the IR images, whereas a poor bond has fewer or no square black spots. In order to study the nature of the relationship, the dissolution behavior of the bare Si(100) surface after bonding was investigated. During the Au/Si(100) eutectic reaction, the dissolution of the bare Si(100) surface primarily occurs by the formation of the craters which result in many square black spots in the IR images. The formation of the craters is ascribed to the anisotropic nature of Au/Si reaction that results in three-dimensional dissolution behavior on the bare Si(100) side. In order to further test the anisotropy hypothesis, Au/Si(111) bonding was also studied. Under the same bonding conditions, triangular black spots were observed in the IR images and triangular pits were found on the bare Si(111) surface. The analysis suggests that the craters on the bare Si(100) surface, in other words the square black spots in the IR images, are the indication of Au/Si(100) eutectic reaction. More craters mean a reaction between Au and Si(100), which occurs uniformly at the Au/Si(100) bonding interface compared to the case of fewer craters. No crater indicates that there is no eutectic reaction in the region. Therefore, the IR microscope may be used to evaluate and compare the different bond strengths qualitatively.","PeriodicalId":55010,"journal":{"name":"IEEE Transactions on Electronics Packaging Manufacturing","volume":"217 1","pages":"31-37"},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89025078","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}