Rapidly Solidified Soft Solder Die-Attach Technology

Soft solders used in the die-attach of power packages are prone to fatigue failure. Conventionally east soft solders typically contain nonhomogeneous Phases and organics. Failure analysis usually shows extensive voids, cracks, and segregation of metals in the die-attach medium, which leads to increased thermal resistance and catastrophic failure during power cycling. Soft solders manufactured via rapid solidification are formed into ribbon directly from the molten metal. The microstructure is homogeneous and free from organics. A study was performed to establish an optimum die-attach process utilizing rapidly solidified soft solder and tO quantify the reliability improvement.