Integration of Microcircuitry Into Microassemblies

The necessity to hybridize newer microcircuitry techniques with existing design capabilities to achieve efficient equipment designs is established. An analysis is presented of the net size and weight advantages calculated for several components of a typical weapons system, as first the micromodule and then, progressively, thin-film and solid-circuit techniques are integrated into the system design. The diminishing returns on the introduction of microcircuitry into many areas of the system emphasize the need for high efficiency in the integration of newer techniques. The potential capabilities of an advanced type micromodule, which still retains the standardized microelement dimensions and assembly procedures, are explored. A further advanced modular interconnection of microcircuitry wafers into a projected microassembly is then described. 0.002 × 0.010-inch copper ribbon conductors are welded to the metallized edge terminations of stacked substrate wafers by an electron beam technique. Interconnection requirement is 1600 terminations per square inch. Sample illustrated showed 2000 terminations per square inch, or 80,000 terminations per cubic inch. Termination capability is increased three times, and effective useful module volume is doubled compared to existing micromodule. Details of materials and processes for the microconnections are described together with a summary of the statistical reliability evaluation. The latter confirms the high reliability objective for this connection.