2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces最新文献

{"title":"Characterization of a thick copper pillar bump process","authors":"W. Flack, Ha-Ai Nguyen, E. Capsuto, C. McEwen","doi":"10.1109/ISAPM.2007.4419942","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419942","url":null,"abstract":"As pin counts and interconnection densities increase there is growing interest in copper pillar bumps for flip chip and wafer-level packaging. This trend is driven by the need to increase interconnect performance as well as reduce interconnect cost. Copper pillars retain their shape during solder reflow, allowing finer interconnect pitches with predictable standoff heights. The fabrication of copper pillar bumps requires the use of a very thick photoresist layer for copper and nickel electroplating. This photoresist material must be capable of coating, exposing, developing, electroplating and stripping with conventional track equipment and standard ancillary process chemicals. For the electroplating process the photoresist profile, plating durability and stripability are important considerations. This study will characterize a photoresist for a single coat, 55 μm thick copper process. The lithographic performance of the thick positive photoresist will be optimized using a broad band, low numerical aperture stepper. Results will show good adhesion to copper with no surface treatment and no photoresist cracking during plating. Cross sectional SEM analysis, process latitude, and copper-nickel electroplating performance are used to establish the lithographic capabilities.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114301521","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":"Case study on the validation of SAC305 and SnCu-based solders in SMT, wave and hand-soldering at the contract assembler level","authors":"P. Biocca, Carlos Rivas","doi":"10.1109/ISAPM.2007.4419935","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419935","url":null,"abstract":"At the contractor level once a product is required to be soldered with lead-free solders all the processes must be assessed as to insure the same quality a customer has been accustomed to with a Sn63Pb37 process is achieved. The reflow, wave soldering and hand assembly processes must all be optimized carefully to insure good joint formation as per the appropriate class of electronics with new solder alloys and often new fluxes. The selection of soldering materials and fluxes are important as to insure high quality solder joints with leadfree solders which tend to wet slower than leaded solders but also the process equipment must be lead-free process compatible. Components must be lead-free and able to meet the thermal requirements of the process but also the MSL (moisture sensitivity limits) must be observed. Board finish must be lead-free and the PCB must be able to sustain higher process temperature cycles with no physical damage but also good solderability to enable subsequent soldering at the wave or hand assembly. Tin-silver-copper has received much publicity in recent years as the lead-free solder of choice. The IPC Solder Value Product Council as the preferred option endorsed Sn96.5Ag3.0Cu0.5 (SAC305) for SMT assembly and most assemblers have transitioned to this alloy for their solder paste requirements. The SAC305 alloy due to its 3.0% content of silver is expensive when compared to traditional leaded process for this reason many contract manufacturers and PCBA assemblers are opting for less costly options such as tin-copper based solders for wave, selective, handsoldering, dip tinning operations. In recent years tin-copper based solders with a variety of elemental additives have emerged which improve the overall properties and performance of tin-copper solders. Tin-copper solder without the incremental additions of certain elements is rarely used but the addition of nickel or nickel and bismuth as found for example in K100 and K100LD respectively do offer improvements in wetting, joint cosmetics and in some cases solder joint reliability. In this conversion SAC305 was used for the reflow process, tin-copper-nickel based solder K100 was used in the wave soldering operation and it was also used in solder wire form for hand assembly. This paper is a summary of the experience at a medium sized assembler in achieving the customer driven mandate to go lead-free and the maintenance of production yields and quality using both tin-silver-copper and tin-copper in the assembly of high end printer boards. Over 120,000 builds were achieved with a 99.6% first pass yield for the overall soldering process.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116300134","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":"Modeling noncoplanarity effects on thermal performance of computer chips","authors":"Ninad Bhave, Nicole Okamoto","doi":"10.1109/ISAPM.2007.4419927","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419927","url":null,"abstract":"A project was undertaken to investigate the effects of noncoplanarity (the absence of perfect surface flatness) on heat transfer in computer chip packages. The goal of the project was to determine the level of model complexity required to accurately determine thermal contact resistance in the presence of non-coplanarity and to determine a method to accurately model these effects using conventional finiteelement and CFD packages. Various types of air gaps were modeled and results tabulated. It was found that heat transfer within gaps on the order of tens of microns could be analyzed by “scaling-up” the model so that minimum cell size of the meshing software was no longer an issue. The scaled and unscaled results agreed to within 97%. Published data and the CFD model results agreed to within 96%. While noncoplanarity was shown to have a significant effect on the thermal contact resistance, it was shown that a complex model of the thermal interface material is not needed for an accurate simulation.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122885127","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":"Tin/silver alloy nanoparticles for low temperature lead-free interconnect applications","authors":"Hongjin Jiang, Kyoung-sik Moon, Fay Hua, C. Wong","doi":"10.1109/ISAPM.2007.4419947","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419947","url":null,"abstract":"A chemical reduction method was used to synthesize tin/silver alloy nanoparticles with various sizes and their thermal properties were studied by differential scanning calorimetry. Both the particle size dependent melting temperature and latent heat of fusion have been observed. The melting point can be achieved as low as 194 °C when the diameter of the nanoparticles is around 10 nm. The 64 nm (average diameter) SnAg alloy nanoparticle pastes showed good wetting properties on the cleaned copper foil surface and the intermetallic compounds formed. These low melting point SnAg alloy nanoparticles could be used for low temperature lead-free interconnect applications.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128755615","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":"Designer heat spreading materials and composites","authors":"A. J. Amaro, K. Murthy","doi":"10.1109/ISAPM.2007.4419928","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419928","url":null,"abstract":"A solid-state system model of “Designer” thermal conducting nano/micro materials used for more effective heat spreading in electronic packaging manufacture is described. The “Designer” materials are much lighter (sp.gr. 2.5g/cc vs. 9.2g/cc) and stronger (modulus 500–820Gpa vs 120GPa) than copper. The material has a coefficient of thermal expansion (1×10−6 vs. 17×10−6) much higher thermal conductivity (500–1200W/mK vs. 390W/mK) and greater heat spreading capabilities. In addition there is the ability to control the thermal conductivity, coefficient of thermal expansion and thermal spreading coefficient in any of the three material dimensions. A brief description characterizing the material and its manufacturing process is here-within. To illustrate the performance gain of using these materials, the base plate of Intel’s CPU Cooler CL-P0030 heat-sink is chosen as an example of a high-heat source cooling device i.e. ≫100W/cm2. Heat greater than 100Wm2 is equivalent to the concentrated focused energy of ≫1000 Suns. (electronic devices melt in seconds without proper cooling) This is a macro example of a replacement for the thermal conducting packaging material structures currently used in electronics.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128297625","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":"Development and characterisation of micrometer sized polymer particles with extremely narrow size distribution","authors":"H. Kristiansen, K. Redford, Z. Zhang, J. Hee, M. Fleissner, P. Dahl","doi":"10.1109/ISAPM.2007.4419931","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419931","url":null,"abstract":"This paper describes size characterisation and mechanical characterisation of micrometer sized polymer particles with an extremely narrow size distribution. Typical applications for this type of particles are as conductive particles (plated with metal) in Anisotropic Conductive Films (ACF) or as spacers for LCD or chip stacking. A number of different instruments and techniques have been investigated to be able to measure size, size distribution and frequency of “off-sized” particles. Due to very tight specifications, none of the instruments were able to provide the full set of information needed, and a combination of different techniques is needed. Also greatly improved technique for mechanical characterisation of such polymer particles are reported in this paper. Adapting a commercial Nano-Indenter and optimising sample preparation and testing procedure have obtained very reproducible and consistent results.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133474556","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":"First-principles simulation study on the effects of dopants on the cohesion of gold grain boundary","authors":"Y. H. Chew, C. Wong, Z. Bakar, J. Ling","doi":"10.1109/ISAPM.2007.4419945","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419945","url":null,"abstract":"The effect of dopants on the cohesion of gold grain boundaries was investigated using the first-principles density functional theory of the thermodynamic model of Rice-Wang. Dopants that have a smaller diameter and lower electronegativity than gold are more beneficial on the cohesion of Au grain boundaries, which originate from both mechanical and electronic interaction, with the mechanical effect domineering. Dopants that bring up grain boundary cohesion should increase the ductility of Au wires. The method shows reasonable agreement with existing experimental data on calcium and berryllium-doped Au wires.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125838490","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 silica on the non-linear electrical property of polymer composites","authors":"Guseul Yun, Yangyang Sun, Fei Xiao, Kyoung-sik Moon, C. Wong","doi":"10.1109/ISAPM.2007.4419939","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419939","url":null,"abstract":"The electrostatic discharge (ESD) control in semiconductor devices is a very important task during the manufacturing stage or for final users. Utilizing polymer based varistors has great advantages in process temperature and dimensional control over the conventional oxide non-linear conductors as a protection mean for electronic device from ESD transient. [5,8] In this paper, the effect of nano-fumed silica on the non-linear electrical property of polymer-metal composites was investigated. We have found that the concentration of silica as an insulating filler plays an important role on the evolution of non-linear IN characteristics of the polymer composite. Furthermore, a polymer composite did not show its non-linear IN characteristics until enough insulative phases were provided within the polymer composite.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133695072","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":"Fine-pitch carbon nanotube bundles assembly using CNT transfer for electrical interconnects","authors":"Lingbo Zhu, Kyoung-sik Moon, D. Hess, C. Wong","doi":"10.1109/ISAPM.2007.4419944","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419944","url":null,"abstract":"Carbon nanotubes (CNTs) have been proposed as electrical interconnects in microelectronic devices to address such problems as stress, electromigration, and heat removal. For electronic device and packaging applications, chemical vapor deposition (CVD) methods are particularly attractive due to characteristic CNT growth features such as selective spatial growth, large area deposition capability and aligned CNT growth. However, the CVD technique suffers from several drawbacks. One of the main challenges for applying CNTs to circuitry is the high growth temperature (≫600°C). Such temperatures are incompatible with microelectronic processes. To fabricate microelectronics devices that incorporate CNT blocks, the CNTs should be selectively positioned and interconnected to other materials such as metal electrodes or bonding pads. However, the adhesion between CNTs and the substrates is usually very poor, which will result in long term reliability issues and high contact resistance. To overcome these disadvantages, we propose a methodology that we term “CNT transfer technology”. The distinctive CNT-transfer-technology features are separation of CNT growth and CNT device assembly at solder reflow temperature. In this paper, we combined our expertise in growth of well-aligned open-ended CNT bundles with the CNT transfer process to assemble CNT bundles for fine-pitch interconnect applications. The open-ended multi-walled CNT arrays could carry higher current density than close-ended CNTs, since the internal walls can participate in the electrical transport. We for the first time developed an in-situ process to grow well aligned CNT bundles by water-assistant selective etching. The process is very efficient, with CNT growth rate of 80 μm/min. To demonstrate the feasibility of transfer process to assemble the fine-pitch CNT bundles, the CNT bundles with diameter, aspect-ratio and pitch of 25 μm, 4, and 80 μm, respectively, were assembled on the copper substrates. The measured resistivity of the long CNTs is ˜ 2.3×10−4 Ω-cm. Due to the capillary force effects, the Sn/Pb show improved wetting properties on open-ended CNT films. It is desirable for CNT interconnect with metal electrode by solder reflow process. The CNT-solder interfaces were analyzed by the SEM. The results indicated that molten SnPb solder form strong mechanical bonding with CNTs. Overall, the advantages of CNT transfer technology are embodied in the low process temperature, adhesion improvement and the feasibility of transferring CNT bundles to different substrates for fine-pitch interconnect applications.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133074174","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":"iNEMI’s gap analysis based on the 2007 electronics roadmap","authors":"A. Rae, R. Pfahl, C. Richardson","doi":"10.1109/ISAPM.2007.4419930","DOIUrl":"https://doi.org/10.1109/ISAPM.2007.4419930","url":null,"abstract":"Participants from almost every sector of the global electronics industry - 565 individuals from 17 countries - contributed to the 2007 iNEMI Roadmap and identified key gaps and challenges facing the electronics industry that could impede further development in critical areas. These gaps were parsed based on their tactical or strategic focus and the Research Committee and Technical Committee of iNEMI prioritized these gaps with the aim of highlighting research needs to the electronics community, academia and government. This presentation outlines the process, the identified gaps and recommendations for action.","PeriodicalId":345300,"journal":{"name":"2007 12th International Symposium on Advanced Packaging Materials: Processes, Properties, and Interfaces","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132136176","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}