Study of Mount Technology on Alumina Multilayer Substrate for Automatic Transmission ECU

Reliability of electronic components assembly mounting technologies used on multilayer alumina substrates has been investigated for Electronic Control Units (ECU's), specifically for use in harsh locations, such as under the hood or directly attached to the transmissions of automobiles. The technology mainly consists of lead-free solder and bare chip assembly. Reliability evaluation tests have been performed in a practical, severe environment, similar to under the hood of automobiles. The experiments mainly consist of thermal cycling and corrosion tests. Computer simulation techniques have also been conducted in order to obtain accurate prediction of product lifetime. The estimated lifetimes of the lead-free solders agree fairly well with the experimental results. Through these studies, ECU's with higher reliability have been applied to automatic transmissions of commercial passenger vehicles.