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Electrically conductive adhesives (ECAs) are an environmentally friendly alternative for traditional tin/lead (Sn/Pb) solders. As a new technology, conductive adhesive technology still has many concerns and limitations. In order that... more
Electrically conductive adhesives (ECAs) are an environmentally friendly alternative for traditional tin/lead (Sn/Pb) solders. As a new technology, conductive adhesive technology still has many concerns and limitations. In order that conductive adhesive technology achieves universal acceptance, ECAs with better properties must be developed. ECAs consist of a polymeric matrix and a conductive filler. Compositions of the polymeric matrix play a very important role in determining the overall properties of ECAs. The objective of this study is to investigate the effects of different curing agents on the properties, especially contact resistance of conductive adhesives. Five polymeric matrix formulations are prepared by mixing five different curing agents, selected from different categories, with an epoxy resin. Using these polymeric matrix formulations, five ECAs are formulated. The properties of these ECAs studied include: curing profile, glass transition temperature (Tg), coefficient of thermal expansion (CTE), moisture absorption, adhesion strength, and shifts of contact resistance of these ECAs on non-noble metals such as tin, tin/lead, and copper, during elevated temperature and humidity aging. Also, a corrosion inhibitor is used to stabilize contact resistance of these ECAs on Sn/Pb. It is found that (1) the curing agents do affect the properties including contact resistance of ECAs and (2) the corrosion inhibitor is effective to stabilize contact resistance on Sn/Pb in all of the five ECA formulations.
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Conventional isotropic conductive adhesives (ICAs) are composed of a polymeric matrix with silver flakes. As an alternative to lead-bearing solder, ICAs offer a number of benefits, but limitations do exist for ICA technology. ICAs filled... more
Conventional isotropic conductive adhesives (ICAs) are composed of a polymeric matrix with silver flakes. As an alternative to lead-bearing solder, ICAs offer a number of benefits, but limitations do exist for ICA technology. ICAs filled with silver flakes generally show higher initial contact resistance, unstable contact resistance, and inferior impact strength. In this study, a new class of isotropic conductive
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Variations of volume resistivity of three electrically conductive adhesives (Ag-filled epoxy, Ag-filled cyanate ester, and Ni-filled epoxy) during 85°C/85%RH aging were studied. Volume resistivity of the two Ag-filled ECAs decreased... more
Variations of volume resistivity of three electrically conductive adhesives (Ag-filled epoxy, Ag-filled cyanate ester, and Ni-filled epoxy) during 85°C/85%RH aging were studied. Volume resistivity of the two Ag-filled ECAs decreased slightly at the beginning of aging and then remained stable. However, the volume resistivity of the Ni-filled epoxy increased substantially. Joint resistance variations of these conductive adhesives with different metals
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Lead-free and environmentally sound interconnect bonding processes are urgently needed. Among the possibilities are electrically conductive adhesives (ECAs) and lead-free solders (Codenhead, R. and DeCoursy, D., 1985). Compared to... more
Lead-free and environmentally sound interconnect bonding processes are urgently needed. Among the possibilities are electrically conductive adhesives (ECAs) and lead-free solders (Codenhead, R. and DeCoursy, D., 1985). Compared to soldering technology, ECA technology can offer numerous advantages such as fewer processing steps which reduces processing cost, lower processing temperature which makes the use of heat-sensitive and low cost substrate possible,
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Page 1. Chapter 11 Electrically Conductive Adhesives (ECAs) Daoqiang Daniel Lu and CP Wong Abstract Recently, significant advances have been made to improve electrically conductive adhesive (ECA) technology. Recent ...
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Research Interests: Treatment Outcome, Medicine, Metabolic syndrome, Humans, Male, and 15 moreBody Mass Index, Risk factors, Aged, Middle Aged, Time Factors, Retrospective Studies, Risk Factors, Abdominal Aortic Aneurysm, Endovascular Procedures, Endovascular Aneurysm Repair, Endoleak, Hypertriglyceridemia, Perioperative, Metabolic Syndrome X, and Medical and Health Sciences
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Isotropic conductive adhesives (ICAs) have been developed as an alternative for traditional tin/lead (Sn/Pb) solders for electronic applications. Compared to mature soldering technology, conductive adhesive technology is still in its... more
Isotropic conductive adhesives (ICAs) have been developed as an alternative for traditional tin/lead (Sn/Pb) solders for electronic applications. Compared to mature soldering technology, conductive adhesive technology is still in its infant stage, therefore, there are some limitations for current commercial ICAs. Two critical limitations are poor impact performance and unstable contact resistance with nonnoble metal finished components. These limitations seriously hindered the wide applications of ICA's. No current commercial ICAs show both desirable impact performance and stable contact resistance. In this paper, novel conductive adhesives were formulated using mixtures of an epoxide-modified polyurethane resin and a bisphenol-F type epoxy resin and a corrosion inhibitor. Cure profiles, rheology, and dynamic mechanical properties of the conductive adhesives were studied using a differential scanning calorimeter (DSC), a rheometer, and a dynamic mechanical analyzer (DMA), respectively. Impact strength and contact resistance with several nonnoble metals (Sn/Pb, Sn, and copper) of these conductive adhesives were tested and compared to those of a commercial conductive adhesive. It was found that these in-house conductive adhesives showed superior impact performance and substantially stable contact resistance with nonnoble metal finished components during elevated temperature and humidity aging