Author: Paul A. Totta Company: IBM Microelectronics Date Published: 4/28/1997
Surface Mount International
Abstract: The electronic packaging business has been centered on surface mounted first level packages for about a decade. The majority of these packages are plastic with peripheral gull wing or J-lead connectors to the second level; however, ball grid array solder connections have grown increasingly popular for both plastic and ceramic carriers. Inside these packages, the dominant chip-to-package interconnection has remained the peripheral, gold ball wire bond connection. Wire bonding has clearly been the most economical and popular interconnect since the invention of the integrated circuit. Therefore, any indication that the semiconductor world may now be changing to flip chip area array joining conveys the notion of a “paradigm” shift since the world is and has been so deeply entrenched in wire bonding. Coincidentally, there has also been a long and growing positive experience with area array, flip chip solder connections for about 25 years in such things as mainframe computers and automotive electronics. The addition of chip underfill polymers has, in addition presented the opportunity to join silicon chips directly to FR4 printed circuit cards for small, light weight mobile and entertainment devices. This paper will discuss the factors which are driving changes in the industry at this time, the limiting factors which will slow change, and other developments which may allow some people to go to flip chip bumping while using current wire bonding equipment.