Trends in Surface Mounting Technology and Beyond

Surface Mounting Technology becomes more essential with increasing pin count of ICs. The opportunities for improved performance, miniaturisation and cost are being exploited largely in Japan and increasingly in the USA, but there remains a lack of comprehension and vision in our own community. Nevertheless, there are some very promising developments of packaging and interconnection in the UK and in Europe. While substrates for hybrids and PCBs are heading towards standard Eurocard size, micropackage types are still proliferating rather than consolidating on a preferred standard. Assemblies of these increasing pin‐count components can be soldered reliably, and improved techniques continue to be developed. Quality and reliability of such assemblies are increasingly aided by on‐line vision and inspection procedures including optical, X‐ray and infra‐red techniques. The compactness and complexity require the emerging solutions in design‐for‐testability. Testability and built‐in self‐test revive the viability and emerging trend towards chip‐on‐board (formerly the well established bare‐chip‐and‐wire hybrid technology), now incorporating VLSI and supported by more advanced interconnections including advanced TAB and integrated thin‐film active devices.