BRAZING PROCESS INVOLVING SINTERING A CONDUCTIVE POWDER BY ULTRASONIC THERMOCOMPRESSION AND ELECTRONIC POWER MODULE PRODUCED BY THIS PROCESS

This soldering process, which uses a filler material and is intended to bond a semiconductor chip (1) to a substrate (2), is of the type wherein an assembly block (1-2-3) comprising the substrate (2), a layer (3) of conductive powder deposited on the substrate (2), and the semiconductor chip (1) is formed, and wherein the assembly block (1-2-3) is subjected to a compressive load (10) between a hotplate (6) and a retaining flange (7). According to the invention, a transverse vibratory movement (11) is applied to the assembly block (1-2-3) at an ultrasonic frequency. Thus a braze joint is obtained by sintering a conductive powder by ultrasonic thermocompression of the semiconductor chip (1) on the substrate (2). The combined action of the compressive load, the temperature and the ultrasound allows a sinter having a high density to be obtained while the temperature is maintained in a range compatible with the technology of the targeted power modules, and with a lower compressive load (10) than known thermocompression processes. According to other features, the conductive powder may consist of silver particles or particles of intermetallic alloys that are formed from metals chosen from the group comprising silver, copper, gold and tin.