Design of metallizations and components for aluminum nitride packages for VLSIC

A program to produce large cofired aluminum nitride (AIN) packages for support of silicon-based high-density multichip modules (MCMs) is discussed. Perimeter leaded packages measuring over 4 in in length and having over 600 leads on 0.025-in centers have been developed. The size and fine lead pitch require tight dimensional control, including 0.1% on both the flatness and the placement of cofired lead pads. These dimensional requirements, as well as the hermeticity and thermal-mechanical reliability requirements for military use, have been met through a combination of engineering/design solutions and the implementations of new material systems and processes.<
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