COMMENTARY — Silver multilayer systems catch on

U.S. fabrication demand for silver in electronic-electrical applications jumped to more than 18.8 million oz. in 1993 from 18.3 million oz. in 1992.

A significant cause of that 500,000-oz. increase is the burgeoning use of silver multilayer thick-film technology.

With close to 10% of the wiring board market, silver multilayer thick-film systems are the wave of the future as the demand for superior reliability is occupied with the ease of high-speed, automated manufacture. Electronic components made of silver thick-films handle power effectively, dissipate heat rapidly and can survive a high-temperature environment. Silver circuits also provide the user with the best conductor of electricity silver.

Silver thick-film components now offer the high-performance reliability demanded for such products as voltage converters, camcorders, hand-held telephones, miniature radios and automobile rear window defrosters. This low-cost circuitry is also applicable to computer controls for lights, machine tools, small appliances and “smart” homes.

In automobiles, silver thick-film components meet the need for high-performance engine controls, in-car temperature controls and memory programs that restore changes in seat positions. They also monitor battery consumption, during periods when the car is not in use, to prevent complete battery drain. In trucks, thick-film systems are used in under-the-hood engine controls, where temperatures reach the melting point of conventional plastic, printed circuit boards.

Multilayer systems use a silver-based thick paste which, on firing, produces an electrically conductive silver “thick-film.” These films range in thickness from 5 to 50 millionths of a metre — 10 to 100 times that of the silver films typically found on electroplated jewelry.

Thick conductive films permit stacking of multiple layers of circuits — one on top of another — interspaced with a thin electrical insulation. The technology was developed for the military because complex electronic circuitry had to be reduced to very small spaces. Now, with massive growth in telecommunications and interactive television, coupled with the demand for advanced computer controls for consumer products such as automobile engine controls, thick-film components are moving into many markets. — From a recent issue of “The Silver Institute Letter.”