Accelerated SLID Bonding for Fine-Pitch Interconnects with Porous Microstructure

Solid-liquid interdiffusion (SLID) interconnectsbased on Cu and Sn-solder are excellent candidates forstacking of Si chips in 3D integration. If the high-temperaturestable intermetallic compound (IMC) Cu3Sn is desired, themanufacturing of the interconnect can be very time consuming(long annealing time for growth of Cu3Sn). In this paper wepropose a method for the accelerated formation of Cu-Cu3Sn-Cu interconnects by selective dissolution of Sn from Cu6Sn5. This leads to a porous network of Cu3Sn. The influence oftemperature, flux and atmosphere onto the pore formation willbe addressed in detail.