Microelectronic packages

1. Body materials
  • Kovar – low expansion to minimize stress when substrates are mounted – closely matches commonly used materials such as GaA
  • Alloy 42 – lowest cost per unit weight of material
  • Alloy 48 - to match CTE of special thermal bases
  • 300 series Stainless steel – to match CTE of special substrates
  • Monel – suitable for soldering without additional plating
  • Invar – near-flat CTE curve at soldering temperatures
  • Aluminum – thermal conductivity, light weight; machinable; weldable; - contacts are soldered in place
  • Titanium (Ti6Al4V & CP) – light weight; bio-compatible; weldable – can be direct sealed
  • Copper – thermal conductivity
  • Tungsten-Copper Composites – thermal conductivity; heat dissipation required
  • Molybdenum-Copper Composites - thermal conductivity; heat dissipation required
  • AlSiC – light weight; thermal conductivity; heat dissipation required
  • GlidCop – light weight; thermal conductivity; heat dissipation required
  • Brass – thermal conductivity; not directly sealed - contacts are soldered in place
2. Contact materials
  • Kovar – for matched seals
  • Copper cored Kovar – electrical conductivity
  • Alloy 52 – for compression seals
  • Copper cored Alloy 52 – electrical conductivity
  • Copper – electrical conductivity; not directly sealed in
  • Copper-Zirconium Composite – stiffness; conductivity
  • GlidCop – conductivity