Lamination of polymer thick film conductor compositions
View Patent ↗This invention provides a method for using a polymer thick film conductor composition to form an electrical conductor in an electrical circuit, the method subjecting the deposited thick film conductor composition to lamination. The invention also provides a method for reducing the resistance of an electrical conductor formed from a polymer thick film conductor composition, the method comprising the step of subjecting the electrical conductor to lamination. The invention further provides devices containing electrical conductors made by these methods.
1. A method for forming an electrical conductor in an electrical circuit, comprising:
a) providing a substrate;
b) providing a polymer thick film solder alloy conductor composition comprising:
(i) 65 to 95 wt % SAC solder alloy powder consisting of tin, silver, and copper, wherein said tin is greater than 90 wt % of said SAC solder alloy powder, and said SAC solder alloy powder possessing an average particle size of 2 to 18 μm and a surface area/mass ratio in the range of 0.2 to 1.3 m 2 /μg; dispersed in
(ii) 5 to 35 wt % organic medium comprising:
(1) a vinyl co-polymer resin of vinylidene chloride and acrylonitrile, dissolved in
(2) organic solvent comprising a dibasic ester,
wherein the wt % of said SAC solder alloy powder and said organic medium are based on the total weight of the polymer thick film solder alloy conductor composition;
c) applying said thick film conductor composition onto said substrate; and
d) subjecting said thick film conductor composition to amination to form said electrical conductor.
2. The method of claim 1 , said method further comprising a step of drying said thick film conductor composition, wherein said step of drying is carried out following step (c) but before step (d).
3. A method for forming an electrical conductor in an electrical circuit, comprising:
(a) providing a substrate;
(b) providing a polymer thick film solder alloy/metal conductor composition comprising:
(1) 35 to 94 wt % solder alloy powder selected from the group consisting of (i) SAC solder alloy powder consisting of tin, silver, and copper, wherein said tin is greater than 90 wt % of said SAC solder alloy powder, (ii) a tin and bismuth alloy powder, wherein said tin is at least 40 wt % of said tin and bismuth alloy powder, and (iii) mixtures thereof, said alloy powder consisting of particles possessing an average particle size of 2 to 18 μm and a surface area/mass ratio in the range of 0.2 to 1.3 m 2 /g;
(2) 1 to 30 wt % metal selected from the group consisting of silver, copper, gold, aluminum and mixtures thereof, said metal consisting of particles possessing an average particle size of 2 to 18 μm and a surface area/mass ratio in the range of 0.1 to 2.3 m 2 /g; and
(3) 5 to 35 wt % organic medium comprising:
(i) a resin that is a vinyl co-polymer resin of vinylidene chloride and acrylonitrile or a phenoxy resin; dissolved in
(ii) organic solvent comprising a dibasic ester or glycol ether, with the proviso that if said resin is a phenoxy resin said metal is silver, wherein said solder alloy powder and said metal are dispersed in said organic medium and wherein the wt % of said solder alloy powder and said metal are based on the total weight of the polymer thick film conductor composition;
(c) applying said thick film conductor composition onto said substrate; and
(d) subjecting said thick film conductor composition to lamination to form said electrical conductor.
4. The method of claim 3 , said method further comprising a step of drying said thick film conductor composition, wherein said step of drying is carded out following step (c) but before step (d).