Browse Prior Art Database

MACRO-DEFECT-FREE Cements for Electronic Packaging

IP.com Disclosure Number: IPCOM000035037D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chandrashekhar, GV: AUTHOR [+4]

Abstract

The features of this disclosure are: (a) the possibility of using MACRO-DEFECT-FREE (MDF) cements for electronic packaging, and (b) improving their properties for use at high humidities by impregnation with a hydrophobic monomer and in-situ polymerization. The recently discovered MDF cements [1, 2, 3], based on ordinary Portland or calcium aluminate cements, but using a hydrophilic polymer as an additive, e.g., partially hydrolyzed polyvinylacetate, and shear mixing, have much higher tensile strength and toughness and lower permeability than ordinary cements. They have the added advantage of low temperature processing and easy forming, when compared to ceramics. They have high electrical strength (8.7 kV/mm) and, in dry atmospheres, have low dielectric constant (8-9 at 1 MHz), low loss factor (0.01-0.

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MACRO-DEFECT-FREE Cements for Electronic Packaging

The features of this disclosure are: (a) the possibility of using MACRO-DEFECT-FREE (MDF) cements for electronic packaging, and
(b) improving their properties for use at high humidities by impregnation with a hydrophobic monomer and in-situ polymerization. The recently discovered MDF cements [1, 2, 3], based on ordinary Portland or calcium aluminate cements, but using a hydrophilic polymer as an additive, e.g., partially hydrolyzed polyvinylacetate, and shear mixing, have much higher tensile strength and toughness and lower permeability than ordinary cements. They have the added advantage of low temperature processing and easy forming, when compared to ceramics. They have high electrical strength (8.7 kV/mm) and, in dry atmospheres, have low dielectric constant (8-9 at 1 MHz), low loss factor (0.01-0.03 at 1 MHz) and are good electrical insulators (DC resistivity of 109 - 1011 ohm cm). These properties are adequate for using them as low cost, large area substrates for electronic packaging. However, in moderate and especially in higher humidities, their electrical properties deteriorate, with the dielectric constant increasing by a factor of 2-4, the loss factor increasing by an order of magnitude and the resistivity decreasing by 4-6 orders of magnitude. Coating the whole surface with a hydrophobic polymer may not be sufficient, since cracking or chipping of even a small area of the coating will lead to diffusion...