Non-Digital Extensions of an Embedded Chip MCM Technology

The GE/Martin Marietta/Texas Instruments embedded chip multichip technology was developed for high performance digital circuits used in aerospace applications. The HDI process involves the placement of bare chips into cavities formed into a base substrate, lamination of a polymer dielectric film over the chips and the substrate, and the formation of vias and interconnect metallization on the polymer film. Multiple levels of interconnect are formed by repeating the film lamination, via formation and metallization steps. The direct metallization to the chip I/O pads eliminates the need for normal chip I/O wire bonds, TAB, or solder bumps. The elimination of these chip connections and the high electrical performance of the polymer/copper interconnect structure result in the superior speed of such embedded chip MCMs. The technology also features high current carrying capability, high reliability in harsh mechanical and thermal environments and high thermal dissipation capability. The inherently high performance features of the embedded chip MCM technology have been exploited in non-digital electronics such as: mixed analog and digital circuits, power conversion and conditioning, microwave transmit and receive (TIR) modules, and optoelectronic modules. The ability of embedded chip HDI to fully shield high frequency devices in a module from other components and the complete elimination of the discontinuities associated with chip I/O attach, makes it ideal for mixed mode operation. Current non digital examples making use of this unique capability are a >400 MHz GaAs 128 X 128 crosspoint switch, a 50 Watt, 85% efficient DC-to-DC converter, a 14 Bit voice / data modem circuit, and a 54 channel 12 Bit instrumentation A/D converter module. All of these unique examples of non-digital extensions of the embedded chip HDI MCM interconnect process will be described along with their unique features, processing and/or structures.