Issue link: https://iconnect007.uberflip.com/i/322206
June 2014 • SMT Magazine 53 TRenDS In THeRMAL MAnAgeMenT MATeRIALS FOR eLeCTROnIC CIRCuITS continues feaTure per and ceramic materials, and offer high reli- ability. Among the products available for better thermal management of electronic circuitry are copper, silver and silver/palladium conductor pastes. For example, Heraeus' lead-free copper conductor system features a thick-film paste combination of metal, glass and ceramic to bet- ter match the ceramic substrate. The system is designed for applications involving high ther- mal and electrical properties, and allows the substrate to survive high-temperature-range thermal cycling requirements. For decades, thick-film technology has been used to build robust electronic circuits on ce- ramic substrates for applications requiring high reliability such as in the automotive, military and aerospace markets. Some of these proven applications include engine control modules, and pressure and fuel level sensors for the auto- motive industry. Alumina, used extensively in building elec- tronic circuitry, can be problematic, especially when trying to keep circuits cool. Alumina does not have high-thermal conductivity; it is eight times less thermally conductive than aluminum nitride. Heraeus has developed several silver/ palladium, silver and copper conductors which are screen printed onto the aluminum nitride to form the circuits. figure 4: Thick-film hybrid circuits are made by screen printing thick-film paste onto a ceramic sub- strate; the paste is fired to produce an electrical circuit.