Development of high temperature electronics packaging technology for long term operation at 250°C

The requirement to install electronic power and control systems in high temperature environments has posed a challenge to the traditional limit of 125°C for high temperature exposure of electronics systems. The leap in operating temperature to above 200°C in combination with high pressures, vibrations and potentially corrosive environments means that different semiconductors, passives, circuit boards and assembly processes will be needed to fulfil the target performance specifications. The fundamental change to enable this step change in packaging performance to be implemented is to switch from the traditional soldered surface mount or through-hole packaged devices assembled onto FR4 printed circuit board materials to bare die mounted onto ceramic, insulated metal or polyimide based substrates with selected materials that are intrinsically more capable of withstanding the high temperatures without degradation for prolonged durations. Results of the evaluation of electronic interconnect materials and substrate technologies that have been submitted to temperatures of 250°C for up to 2000 hours will be presented; including novel adhesive formulations and insulated metal substrates. Phenomena such as thermal migration and material deterioration due to high temperature exposure in air and inert atmospheres will be described, backed up by non-destructive scanning acoustic microscopy (SAM) of samples assessed throughout the long term testing programme. This work forms part of the UPTEMP project has been set-up with support from UK Technology Strategy Board and the EPSRC, which started in March 2007 with 3 years duration. The project brings together a consortium of end-users (Sondex Wireline and Vibro-Meter UK), electronic module manufacturers (GE Aviation Systems Newmarket) and material suppliers (Gwent Electronic Materials and Thermastrate Ltd) with Oxford University - Materials Department, the leading UK high temperature electronics research centre