Browse Prior Art Database

Solder Seal and Package Cap Design

IP.com Disclosure Number: IPCOM000042875D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

DiGiacomo, G: AUTHOR [+2]

Abstract

The cap design has a bilevel orthogonal seal band on the periphery of the cap that forms a ceramic barrier between the seal band and the cap cavity. Hermetic solder seals for semiconductor packages are well known. However, with the conventional solder seal the molten solder, during the sealing operation, can enter the package cavity and cause shorting between the terminals of the device and/or the metallurgy on the surface of the substrate. This seal structure includes a solder-wettable seal band 10, upon substrate 12, that defines the peripheral edge of ceramic cap 14. In opposed and in spaced relation on cap 14 is provided a solder-wettable band 16.

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Solder Seal and Package Cap Design

The cap design has a bilevel orthogonal seal band on the periphery of the cap that forms a ceramic barrier between the seal band and the cap cavity. Hermetic solder seals for semiconductor packages are well known. However, with the conventional solder seal the molten solder, during the sealing operation, can enter the package cavity and cause shorting between the terminals of the device and/or the metallurgy on the surface of the substrate. This seal structure includes a solder-wettable seal band 10, upon substrate 12, that defines the peripheral edge of ceramic cap 14. In opposed and in spaced relation on cap 14 is provided a solder-wettable band 16. Sealing bands 10 and 16, as is conventional in the art, consist of a metallizing layer of the refractory metal bonded to the ceramic substrate and cap, and an overlying layer of a solder-wettable material, such as nickel, copper, or the like. A solder preform 18 is positioned between bands 10 and 16, as indicated in Fig. 1, and the assembly is heated to melt the solder. The resultant seal is illustrated in Fig. 2 wherein the solder has melted, forming a hermetic seal between the cap and the substrate. The ceramic-to- ceramic interface area 20 between the cap and the substrate prevents any solder, flux, or other materials from entering the package cavity 22.

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