ULTRA-FINE FEATURE PRINTED-CIRCUITS AND MULTICHIP MODULES

As semiconductor devices evolve, so do the packages that house them an d the printed circuit boards (PCBs) that support and interconnect them to form systems. The higher numbers of connections per device are squ eezed into smaller pitches, both on the package and in the PCB, to fit into the available space and to improve electrical performance. Ultim ately, individual packages are not required for each device. This pape r describes substrates available from GEC-Marconi suitable for carryin g and interconnecting packaged or unpackaged devices, or a combination of them, manufactured using techniques and materials familiar to the PCB industry. Multi-chip modules using lamination techniques to make t he substrates (MCM-Ls) are a natural extension of printed circuit tech nology to meet the ever increasing demands of system integration and d ensity. As with other forms of multi-chip module (MCM), the interconne ction density is so high that most circuits need very few signal layer s - often only two. The substrate can also incorporate layers to contr ol thermal expansion and extract heat. MCM-L substrates are extraordin arily versatile; they can accommodate packaged ICs (for example, fine- pitch surface mount technology), unpackaged ICs, other MCMs, and odd-f orm components. These ultra-fine feature substrates can provide soluti ons for a wide range of sizes, complexities, performance and market se ctors at competitive prices.