Packaging of Large Area Power Chips - Extending the Limits of Standard Module Technology

Increasing the power density of the standard technology is a continuous challenge in power module development. While single chip packages like hockey pucks are available for very large die sizes, the application of these packages requires a high mechanical and constructive effort. The state-of-the-art technology for high volume phase leg modules comprises a solder connection between a chip and an insulating substrate with bond wire top surface connection and a second solder connection between the populated substrate and a base plate - but this bond wire technology is currently limited to a die size of less than 20 x 20mm(exp 2). Pushing out these limits to new frontiers is the goal of this investigation. Presenting a semi-controlled input rectifier phase leg module - composed of a thyristor and a diode of 24.3 x 24.3mm(exp 2) and 22.4 x 22.4mm(exp 2) chip size, respectively - the challenges with respect to the reliability and lifetime are explored and possible improvements to enhance the classical technology to meet the reliability requirements are presented.