Shape matching-assisted self-assembly of microchips on a silicon substrate

The paper describes a process of mass assembly of microchips onto silicon substrate using mechanical shape locking mechanism. A certain pattern was fabricated on the backside of 1 times 1 mm microchips by conventional microfabrication technique. A complementary pattern was also fabricated on 8" carrier wafer which contains about 2000 receptor sites. Under the optimal agitation condition, the microchips were self-assembled into the receptor sites of carrier wafer with an average assembly yield of 95.8% within 10 mins. The assembled microchips on carrier wafer were then aligned and gang bonded with substrate wafer with solder interconnection. The yield for gang bonding is about 98%. With this method, the assembly of microchips with unique face orientation and in-plane orientation can be simultaneously achieved. This parallel assembly technique also greatly increases throughput for mass production compared with the conventional "pick-and-place" technique