Solder Sealing Semiconductor Packages

After a comparison of current common sealing systems, a review of the development and properties of metal sealing alloys is presented. Development stages leading to a new laminated composite system for seal alloy preforms is described and results are presented of differential thermal analysis (d.t.a.) scans showing reflow characteristics. Also described are the solderability and aging properties of a nickel alloy plated seal lid which together with the alloy constitute a totally new hermetic seal system. Mention is also made of a composite gold plating scheme Currently in development, designed to meet the new updated corrosion requirements of MIL-STD-883.