Glass to metal / Ceramic to metal

Glass to metal

From the beginning, this technology has been at the center of Egide’s capabilities. The body or package is metal as are the feedthru pins. The pins are held in place by glass beads which then isolate the pin from the body. This isolation is a hermetic seal.

Many of the materials used are special alloys, the most common of which is Kovar, an alloy of Iron, Nickel and Cobalt. Other materials used are Molybdenum, Copper-tungsten, aluminum – silicon carbide or Titanium where applications require significant thermal dissipation or lower weight.

The final product is assembled by brazing (soldering) in furnaces, at very high temperatures. The braze itself is made up of special alloys, such as AuSn, AuGe or AgCu.

Ceramic to metal

InCeramic to Metal sealing is less common than Glass to Metal sealing, but is growing in the number of applications as it posseses a number of advantages over GTMS. The package is designed much the same as GTMS in that the body and pins are a specialized metal and the brazing process is still used, but instead of glass beads ceramic inserts are used.

Typically, instead of individual beads of ceramic, a slot is machined into the metal package, in which a block of ceramic with screen-printed tracks is then brazed in place. This is known as multi layered ceramic feedthru technology.

There are also many applications that mimic the GTMS step whereby the individual pins are isolated by ceramic beads instead of Glass beads. Many Infrared applications use these.