Electrically conductive adhesives are composites of polymeric matrices and electrically conductive fillers. The polymeric resin, such as an epoxy, a silicone, or a polyimide, provides physical and mechanical properties such as adhesion, mechanical strength, impact strength, and the metal filler (such as, silver, gold, nickel, or copper) conducts electricity. Metal-filled thermoset polymers were first patented as electrically conductive adhesives in the 1950s. Recently, electrically conductive adhesive materials have been identified as one of the major alternatives for lead-containing solders for microelectronics packaging applications.
Electrically conductive adhesives offer numerous advantages over conventional solder technology, such as environmental friendliness, mild processing conditions which enable the use of heat-sensitive and low-cost components and substrates, fewer processing steps which reduce processing cost, low stress on the substrates, and fine-pitch interconnect capability which enables the miniaturization of electronic devices. Therefore, conductive adhesives have been used in flat panel displays such as LCD and smart card applications as an interconnect material and in flip-chip assembly, CSP (chip-scale package) and BGA (ball grid array) applications in replacement of the solder.
As we mentioned before silver is one the metals that is used in electrically conductive adhesive pastes. Among different metal particles, silver flakes are the most commonly used conductive fillers because of the high conductivity and the maximum contact between flakes. In addition, silver is unique among all the cost-effective metals by nature of its conductive oxide
Silver Conductive Adhesive Paste bonds very well to a variety of surfaces. This adhesive bonds very well to most substrates used in electronic assemblies; resists thermal and mechanical shocks; and provides the low resistivity needed for many operating conditions.
So it can be said that an electrically conductive silver-filled epoxy adhesive that is an excellent replacement for RTV silicones and rigid epoxy systems where a compliant, electrically conductive adhesive system with good bond strength to a variety of substrates is required. They can find extensive use in bonding electronic components to circuit boards and leadframes, and it is an excellent choice where solder temperatures are too high for the substrates.
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