Large Thin Organic PTFE Substrates for Multichip Applications

Very high performance computer applications have created a demand for large organic substrates capable of interconnecting one or a few ASIC semiconductor devices with packaged memory devices. The electrical advantages offered by the use of a thin PTFE composite substrate were coupled with intrinsic mechanical advantages to create very high performance applications. The application development required interactions of design, fabrication, and new manufacturing technology to obtain rapid prototype production and allow a successful ensuing manufacturing ramp. One such package application involved using a 0.47mm thick PTFE substrate in a 65mm size format, having 8 memory devices surrounding a central ASIC, with numerous capacitors, in double-sided format. The application was developed as a pluggable module by using SMT attached pin/socket, and has a heatspreader which is in thermal contact with all devices and further provides flatness control once attached using thermal and electrically conductive adhesives.