Developnent of solder bump fabrication in multicalp modules

Recently, many now kinds of high-donsity bonding tocniques hays been developed [1],[2]. Among those is the solder bump fabrication techniques for use in manufacturing high-density IC's and Multichip Modules. In 1991, we developed an automatic high-density solder ball mounter and presented the result in IEMT, Tokyo[3]. This mounts a total of more than 600 solder balls ( 0.40 millimeter in diameter ) on a substrate at once and forms solder bump by reflow ( Vapor Phase Soldering ). We further continued to develop the technology of mounting many smaller solder balls on a substrate at once and recently manufactured another automatic high-density solder ball mounter. This mounts a total of more than 600 solder balls ( 0.25 millimeter in diameter ). We have perfectly understood how to mount many small solder balls on a substrate at once and fabricate solder bumps. This paper describes an automatic high-density smaller solder ball mounter.