SRI International has been a certified QML (MIL-PRF-38535) manufacturer for monolithic integrated circuits produced by the Generalized Emulation of Microcircuits (GEM) program since 1997 and all GEM microcircuits are delivered in compliance with the requirements of MIL-PRF-38535. This includes complete traceability, total compliance with customer procurement requirements, and delivery with a certificate of conformance. Adhering to QML requirements ensures the integrity of the system, and the delivery of a highly reliable microcircuit that will work to specifications in rugged military environments.
When a request for an integrated circuit (IC) is received, the SRI designers review the microcircuit specification. Experience has shown, paper documentation obtained from data books, slash sheets, source control drawings and OEM data are often incomplete and require detailed verification.
Missing data is captured from known good samples of the obsolete IC using both electrical characterization and physical reverse engineering processes. The result of this analysis is an Emulation Design Specification which contains the required microcircuit specifications, and clarifies any errors, ambiguities or critical omissions in the original documentation. For this reason, it is highly beneficial for the customer to provide a known good device to ensure the most accurate emulation result.
SRI has developed a split manufacturing process, in which wafer lots are processed through the majority of the manufacturing flow and held in inventory. This technology is based on gate arrays fabricated with predefined circuit elements (base wafers) which are interconnected by multiple levels of metal conductors (wafer personalization) and minimizes the wafer production time for emulated devices. This approach allows Integrated Circuits (ICs) that were originally manufactured in diverse technologies to be produced from a managed inventory of standardized base wafers. An overview of the SRI Production System for emulating microcircuits is illustrated above.
Design and circuit verification tasks are performed using a suite of CAD tools. SRI designers begin the design process by simulating the logic and circuit networks to predict their functionality and electrical performance. Then these logic and circuit configurations are rendered into geometric design (the “layout”). The physical effects of the layout on logic and circuit networks are evaluated to ensure that the resulting microcircuit achieves desired function and performance. Additional metallization is added as needed to satisfy current density, bussing, and other requirements.
The layout data is used to create the photo masks (tooling) for defining metal interconnects on the Emulation base wafers to complete the fabrication (wafer personalization) and produce the final microcircuits.
Once the design is complete, the part can be manufactured in our in-house, U.S.-based, Government-certified Trusted wafer foundry. For each new design, a single wafer can be processed through the final stages to create the part. This on-demand manufacturing process allows SRI to significantly reduce the time to manufacture the required part.
The wafers are tested to verify that the wafer process parameters and the individual circuit characteristics conform to performance and reliability requirements. Die meeting these requirements are mounted into the appropriate package, wire bonded, and hermetically sealed by QML-qualified U.S.-based assembly contractors.
The assembled parts are then individually tested over the full temperature and performance range and verified to meet all requirements of the specification. Screening of package integrity, life test reliability and the full complement of reliability tests are performed in accordance with SRI QML standards following the requirements of MIL-PRF-38535.
All Emulated parts are fully traceable and delivered with a certificate of conformance against customer procurement requirements.
Emulation technology can be applied to replace a single IC, to replace multiple ICs with a single device, redefine the function and capabilities of an existing board, or even to combine the function of multiple boards into a single IC.