Microwave integrated circuit package to eliminate alumina substrate cracking

摘要

A MIC package housing that reduces or completely eliminates alumina substrate cracking due to thermal expansion rate differences between the housing and the alumina by using a low-expansion iron-nickel alloy, such as commercially available Carpenter 49, made to ASTM Specification A-753- 78 (Alloy 2) and MIL-N-14411B (MR) (Composition 3 and 4). Such a housing places compressive stresses no glass-to-metal seals used in hermetic feedthroughs and the glass is fused and the stresses relieved by a special process of annealing. Manufacturing yields are improved and very large alumina substrates can be used and are attached by hard soldering.