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Novel Approach to Produce Solderable Polymer Thick Film Conductors Filled with Copper Metallurgy

IP.com Disclosure Number: IPCOM000114820D
Original Publication Date: 1995-Feb-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Lauffer, JM: AUTHOR [+3]

Abstract

Polymer thick film conductors are mechanical blends of metallic particles dispensed in a variety of organic compounds. The resultant blends form pastes which are subsequently screened and cured at predetermined temperatures, depending on the polymers and solvents used in these blends.

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Novel Approach to Produce Solderable Polymer Thick Film Conductors
Filled with Copper Metallurgy

      Polymer thick film conductors are mechanical blends of metallic
particles dispensed in a variety of organic compounds.  The resultant
blends form pastes which are subsequently screened and cured at
predetermined temperatures, depending on the polymers and solvents
used in these blends.

      The majority of commercially available polymer thick film
conductors are based on silver metallurgy, because the metal;
exhibits the highest known electrical conductivity and exhibits high
corrosion resistance.  To a much lesser extent, polymer thick film
conductors using other metals such as copper, gold, and nickel are
also available from paste suppliers.

      From both cost and electrical conductivity standpoints, copper
filled polymer conductors offer the ideal material system.  However,
copper is easily oxidized, virtually at all temperatures, which
results in poor solderability and an unacceptable electrical
conductivity.  Based on extensive evaluation of these two materials,
it was found that they do undergo certain amount of oxidation and
have a narrow processing window which results in low yields and high
scrap rates.

      From a theoretical standpoint, oxidation can be minimized by
using either oxygen scavengers or fluxing agents.  Based on this
principal, several mono and di carboxylic acids were identified as
candidates for minimizing oxide formati...