The die attach process remains a key step in the manufacture of power packages and high reliability automotive devices to ensure product reliability. Heraeus die attach solder pastes are the right choice when high operating temperatures require high melting points for the solder connection.

Harsher conditions, higher currents and rising customer expectations continuously increase the reliability requirements for crucial aspects such as solder connections. Frequent on/off cycling is a challenge for the die attach and often leads to thermal and mechanical fatigue defects. To maximize reliability, engineers must identify the optimum combination of material performance and properties.

Since solder pastes for die attach are used in high temperature applications, there are several special demands on the flux: The flux system has to vaporize slowly when temperature rises during reflow soldering. The flux must be able to protect the alloy powders and must not burn at >300°C or leave charred residues which are difficult to remove.

Heraeus solder paste flux systems for high-temperature-high-lead alloys are engineered to provide adequate protection to the powders. This minimizes voids and leaves minimal residues after solvent clean.