TWI Industrial Member Report Summary 591/1997
J A Fernie
High thermal conductivity ceramics such as AlN and SiC are of increasing interest to the electronics industry as a replacement for alumina substrates. This work has demonstrated the feasibility for joining these materials to heat sinking metals such as copper and aluminium.
Alumina (Al2O3) has been the dominant material for electronic ceramic substrates for a number of years. However, its selection was always a compromise over a range of properties, cost and availability. Advances in technology now demand materials with properties beyond the capabilities of alumina. Materials are required with superior thermal conduction, to allow heat to be removed more efficiently, and with a coefficient of thermal expansion closer to that of silicon, to reduce stresses within the system during both manufacture and use. This report reviews potential alternative substrate materials and discusses various joining technologies which would allow their incorporation into power devices.
Current technologies have been developed specifically for oxide ceramics, such as alumina, and are presently unsuitable for non-oxide ceramics such as AlN and SiC. This programme aimed to develop modifications to conventional techniques so that non-oxide ceramics can be bonded using existing facilities and skills within the industry. This should reduce the inertia in industry using these newer ceramic materials.
- To develop bonding procedures for attaching high thermal conductivity metals such as copper and aluminium to ceramic substrates of AlN and SiC.