Die Bonding/ Die Attach

First Level Interconnects

Die bonding is the process of attaching a semiconductor die (IC chip) to a substrate or package. Common techniques include epoxy, eutectic, and silver sintering. Each method has its advantages. Epoxy die bonding, using both conductive and non-conductive epoxies which usually cures at 80°C to 150°C, while eutectic die bonding, suitable for high-reliability applications for advanced packaging and power electronics. Commonly used solder alloys for eutectic die bonding are 100In, SAC305, 80Au20Sn, and 88Au12Ge preforms; these materials are usually vacuum reflow at temperatures up to 450C. Silver Sintering uses silver paste and is a reliable alternative to traditional eutectic die bonding for power electronics and RF modules applications. Silver sintering offers superior thermal, electrical conductivity, and high-temperature stability.

Epoxy die bonding is a popular die bonding method due to its cost-effectiveness and speed, with epoxy being dispensed in various ways like line, dot, or through epoxy stamping processes.

Eutectic Die bonding is a common die bonding process for power electronics and RF modules, using specific solder alloys like 100In, SAC305, 80Au20Sn and 88Au12Ge where the die is placed onto the preform and heated to the alloy’s melting point, forming a strong, reliable bond with excellent thermal and electrical conductivity.

Silver sintering Die bonding is a pressureless or pressure-assisted silver sintering process that offers thermal and electrical conductivity comparable to eutectic die bonding, while retaining benefits of epoxy bonding and avoiding issues like voiding, flux, and high temperatures associated with soldering.