Technology Trends: Past, Present, and Future

Since the invention of flip chip technology by IBM about 40 years ago, there has been a continuous need for increased I/O density. More recently fine pitch technology is being enabled in Pb-free through Cu pillar and Sn–Ag solders. Stiffer Pb-free interconnection coupled with fragile low-k dielectric materials imposes a significant challenge on first level packaging. In response to increased number of interconnections and higher performance needs, additional technologies are emerging, such as the following: fine pitch flip chip (<60 μm pitch) interconnections, 3D with and without TSV’s, liquid phase connections, and bond-on line. This introductory chapter covers these technologies and sets the stage for current and future flip chip technologies discussed throughout the book.