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Analysis Technique for Ceramic Green Sheet Microporosity

IP.com Disclosure Number: IPCOM000088844D
Original Publication Date: 1977-Aug-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Nufer, RW: AUTHOR

Abstract

In this process, green sheet microporosity is measured by immersing the sheet in a nonreactive fluid and measuring the amount of fluid absorbed.

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Analysis Technique for Ceramic Green Sheet Microporosity

In this process, green sheet microporosity is measured by immersing the sheet in a nonreactive fluid and measuring the amount of fluid absorbed.

Ceramic green sheets are formulated to provide a microporous sheet structure consisting of about 40% void volume. This porosity exists throughout the entire sheet. However, the outer surfaces have a higher concentration of binder which interrupts and reduces the surface porosity. This polymer layer, therefore, reduces the transmission or diffusion of any substance that must enter or evolve from the internal structure. This surface porosity is a significant item in multilayer ceramic technology in screening process steps. The absorption of low vapor pressure metallurgical paste solvents to dry and initially set the screened metallurgical pattern is necessary. Large variations in surface porosity will cause widely different results in screening, particularly with ink oil types of paste where a thin low porosity film will cause a slow absorption of paste solvents and a lateral flow of paste, producing shorts in poor via clearances.

In this process green sheets are immersed in the high molecular low vapor pressure nonreactive FREON* E-4 fluorocarbon. The fluorocarbon absorbs at a rate relative to the sheet porosity. Either the dull (top) or shiny (bottom) side of the green sheet can be evaluated and classified by this process for determining sheet screening performance...