Browse Prior Art Database

Orientation of Electrical Connectors on a Substrate

IP.com Disclosure Number: IPCOM000043397D
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Hsieh, SC: AUTHOR

Abstract

Orienting elliptically shaped chip connector (C-4) pads radially on a substrate decreases stress on the pads caused by thermal gradients. Referring to the figure, each C-4 pad 1 is disposed on a substrate 2 so that its minor axis extends radially from the center of an integrated circuit chip 3. This orientation significantly decreases the moment of inertia which may occur during heating or cooling due to different coefficients of thermal expansion between the substrate and the chip. Direct shear and bending stresses are both reduced. This orientation is particularly useful in multilayer ceramic and metallized ceramic polyimide modules wherein access to the C-4 pads is not solely dependent on the substrate surface geometry.

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Orientation of Electrical Connectors on a Substrate

Orienting elliptically shaped chip connector (C-4) pads radially on a substrate decreases stress on the pads caused by thermal gradients. Referring to the figure, each C-4 pad 1 is disposed on a substrate 2 so that its minor axis extends radially from the center of an integrated circuit chip 3. This orientation significantly decreases the moment of inertia which may occur during heating or cooling due to different coefficients of thermal expansion between the substrate and the chip. Direct shear and bending stresses are both reduced. This orientation is particularly useful in multilayer ceramic and metallized ceramic polyimide modules wherein access to the C-4 pads is not solely dependent on the substrate surface geometry.

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