Development of Hermetic Microminiature Connectors

Abstract

Miniaturization of hermetic packages has provided the incentive to develop a new family of hermetic microminiature connectors. Microminiature connectors, with a pin spacing of 1.27 mm, have previously been available only in the nonhermetic form. New microminiature connectors with compression seal materials, 304 Stainless Steel housings, Alloy 52 pins, and TM-9 Glass insulators, were examined because compression seals are currently used in larger hermetic connectors and are typically designed to create a residual compressive stress state in the insulator during manufacturing. The new microminiature connectors with compression seals were evaluated analytically with two and three-dimensional finite element models and experimentally by fabrication of prototype connectors. The finite element analyses predicted the development of undesirable tensile stress in the insulator during manufacture and identified the mechanism responsible for the generation of tensile stress in the glass. The experimental investigation confirmed the existence of undesirable tensile stress in the glass with the observation of crack development during manufacture. Since the design requirements would not allow the geometric modifications needed to manufacture crack-free connectors with compression seals, insulator materials that generate a matched seal with 304 Stainless Steel housing were developed. Connectors with these matched seals were successfully manufactured.