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Increased Ceramic Substrate Strength by Surface Distribution of Smaller Particle Sizes

IP.com Disclosure Number: IPCOM000040564D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Berghahn, TA: AUTHOR [+2]

Abstract

The presented process increases the strength of glass-ceramic substrates by using a finer grained powder of the same material on its surfaces prior to sintering. The top and bottom surface layers of the ceramic substrate contain a smaller and narrower particle size distribution than the inner layers. The same material composition is used, but the particle size is varied with the finer grained material on the surfaces. The strength of these substrates was found to be 50% stronger than typical substrates using constant powder grain size throughout. By putting the finer grained material on the outside, the surface flaws are less and the outermost layer will become rigid before the inner layers.

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Increased Ceramic Substrate Strength by Surface Distribution of Smaller Particle Sizes

The presented process increases the strength of glass-ceramic substrates by using a finer grained powder of the same material on its surfaces prior to sintering. The top and bottom surface layers of the ceramic substrate contain a smaller and narrower particle size distribution than the inner layers. The same material composition is used, but the particle size is varied with the finer grained material on the surfaces. The strength of these substrates was found to be 50% stronger than typical substrates using constant powder grain size throughout. By putting the finer grained material on the outside, the surface flaws are less and the outermost layer will become rigid before the inner layers. When the inner layers completely sinter and crystallize, they attempt to shrink but are constrained by the outer layers because crystallization begins from the surface rather then the bulk. This process places the outer layers in compression which increases the substrate strength.

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