GaAs multichip module for a parallel processing system

The module described is a high-speed data transfer network for a parallel processing system. The high-speed data transfer network connecting multiple processor units was realized in a module using 8-bit slice GaAs bus logic (BL) LSIs which operate at 100 MHz. The GaAs multichip module consists of 12 GaAs BL LSIs in a 3*4 matrix. Each GaAs chip is sealed in a chip carrier with bumps. The chip carrier is flip-chip bonded to a copper/polyimide thin-film multilayer substrate. The characteristic impedance of the signal lines on the module is controlled to 75 Omega to be compatible with the GaAs original interface level. The thin film termination resistors are made of Ni/Cr in the substrate to prevent reflections. Heat generated from the module, which has a total of 90 W of power dissipation, is transferred through four heat pipes with fins by forced-air cooling at <2 m/s. A 3-Gbit/s data transfer rate can be realized by four stacked modules of 38 GaAs BLs.<
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