Microcircuit Packaging
GEM microcircuits use ceramic packages as the final stage of semiconductor device fabrication. The wafers for these microcircuits are processed in a QML (Qualified Manufactures List) certified wafer fab located in Princeton, NJ. The completed wafers then undergo functional and electrical testing. The wafers and package piece parts (i.e., substrates and lead frames) are then shipped to a QML domestic packaging house. Wafers are thinned, diced, and inspected. Each die is then attached to the package assembly and undergoes a wire bonding process. The packaged parts are returned to SRI for final testing. The package assembly process and final testing follow the requirements specified for MIL-PRF-38535 Class Q microcircuits. Any additional items required by the customer’s procurement specification will also be performed during package assembly and final testing.
The physical dimensions of the package are part of the F3I (Form, Fit, Function, and Interface) requirements for an emulated microcircuit. For emulations of microcircuits conforming to a Military Standard Drawing or M38510 slash sheet, the package dimensions are specified by MIL-STD-1835. For other types of drawings, the dimensions will be those specified by the customer’s procurement specification. In all cases a search will be done to find the closest match to the original package.
The GEM array selected for the emulation and the package must meet the manufacturing requirements for package assembly established by the package assembly vendor. If a dimension of a proposed package is outside the tolerance limits of the customer’s procurement specification, a waiver may be requested. This occurs when there are small differences in dimensions between the original and proposed packages and the deviation is not considered critical. It is sometimes not possible to locate a package which has the proper dimensions and is compatible with the required GEM array die size. In those instances, a custom package will need to be designed and manufactured.
The GEM Program maintains an inventory of package assemblies for future delivery orders. Packages with long times are purchased in advanced to have them available at the time of manufacturing.

