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Ranier Voltage Distribution Plate

IP.com Disclosure Number: IPCOM000046677D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Bolda, FJ: AUTHOR [+4]

Abstract

This article describes interconnect structures which allow a device designer to make use of the conductive properties of the steel substrate in a porcelain-on-steel circuit board. Porcelain-on-steel substrates are gaining acceptance as replacements for standard printed circuit boards as well as for hybrid circuit applications. The substrates have advantages where high rigidity, good thermal conduction and cost are important. Conventionally, the steel substrate has been used strictly as a rigidifier and thermal conductor or heat sink. Fig. 1 is a cross section of a porcelain-on-steel circuit board showing the components required to complete an electrical connection to a gold pad. Fig.

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Ranier Voltage Distribution Plate

This article describes interconnect structures which allow a device designer to make use of the conductive properties of the steel substrate in a porcelain-on- steel circuit board. Porcelain-on-steel substrates are gaining acceptance as replacements for standard printed circuit boards as well as for hybrid circuit applications. The substrates have advantages where high rigidity, good thermal conduction and cost are important. Conventionally, the steel substrate has been used strictly as a rigidifier and thermal conductor or heat sink. Fig. 1 is a cross section of a porcelain-on-steel circuit board showing the components required to complete an electrical connection to a gold pad. Fig. 2 is a cross section showing an interconnect allowing a copper conductor 10 to be electrically linked to the steel substrate 12 permitting the steel substrate 12 to act as an earth ground or as a common current path. The interconnect between the copper conductor 10 and the steel substrate 12 is formed by mechanically deforming or dimpling the steel substrate 12 in a region 14 before the substrate is coated with an enamel (porcelain) layer. The enamel layer on the upper surface of the substrate 10 is applied using masking techniques which keep the upper surface 16 of the dimple free of enamel. A .1 mil thickness layer 18 of sulfamate nickel can be applied to the surface 16 without altering the essentially flush topography of the upper surface. An alt...