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Elimination of Porosity in Filled Fluoropolymer Composite Materials

IP.com Disclosure Number: IPCOM000107245D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 1 page(s) / 65K

Publishing Venue

IBM

Related People

Afzali-Ardakani, A: AUTHOR [+6]

Abstract

Fluorocarbon composite materials comprised of ceramic or glass filler are of considerable interest for electronic packaging because of their low dielectric constant and high thermal stability. These materials are typically processed by lamination to a metal substrate to achieve material densification. However, it is known that the resulting films possess microporosity attributed the CTE mismatch between the filler and fluoropolymer resin and/or the use of surfactants in the starting dispersion. This porosity leads to processing and device reliability concerns. Furthermore, the porosity allows air entrapment which can cause photoresist underdevelopment during image exposure as a result of radical scavenging by entrapped O2 .

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Elimination of Porosity in Filled Fluoropolymer Composite Materials

      Fluorocarbon composite materials comprised of ceramic or glass
filler are of considerable interest for electronic packaging because
of their low dielectric constant and high thermal stability.  These
materials are typically processed by lamination to a metal substrate
to achieve material densification.  However, it is known that the
resulting films possess microporosity attributed the CTE mismatch
between the filler and fluoropolymer resin and/or the use of
surfactants in the starting dispersion.  This porosity leads to
processing and device reliability concerns.  Furthermore, the
porosity allows air entrapment which can cause photoresist
underdevelopment during image exposure as a result of radical
scavenging by entrapped O2 .

      A method is described by which the porosity can be
significantly reduced or eliminated by filling the pores with a
soluble fluoropolymer material.  One approach is to coat or dip a
laminated composite film into a Teflon AF (DuPont)/Fluorinert (3M)
solution.  Teflon AF is a copolymer of tetrafluoroethylene and
perfluoro-2,2-dimethyl-1,3- dioxole which can be dissolved in
perfluoroalkane Fluorinert solvents.  During this treatment, the
solution is readily absorbed into the porous film because of the
compatible chemical nature and wettability between the perfluorinated
solvent, soluble fluoropolymer, and fluoropolymer film.  On
evaporation of the Fluroinert...