| Abstrakt: |
With the development of portable equipment such as IC cards, LCDs, cellular telephones, and notebook computers, the recent trend of LSI packaging has been a rapid movement toward increased thinness and the adoption of chip-on-board (COB) designs. The conventional transfer molding technique has difficulty in meeting these requirements. It also has economic disadvantages such as high die cost, resin loss in the runners and sprue, and long processing time. This paper describes the printing encapsulation system (PES), developed as a replacement for transfer molding in LSI processing. The technique is suited to mass production, is readily applied to packages less than 1 mm thick, and is economically effective, since it does not require expensive dies and has minimum resin loss. The resin used in PES is liquid epoxy, which must have good thixotropic stability after printing and curing. High-purity silica microparticles are an effective thixotropic agent that can tolerate long printing times. To prepare for the future production of larger LSI packages, stress reduction is achieved by using silicone resin to modify the epoxy. The reliability of a 10 × 10 mm LSI prepared with this modified epoxy resin was tested on a ball grid array (BGA) package and was found to be highly reliable. The use of the PES technique and the low-stress epoxy resin should make it possible to extend the application to many new types of packaging, such as BGA, PLCC, CSP, MCM, TAB, and the like. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 2, 80(2): 67–76, 1997 [ABSTRACT FROM AUTHOR] |
