Photonic sintering of polymer thick film copper conductor compositions

1. A polymer thick film copper conductor composition comprising:

(a) 40 to 95 wt % copper powder possessing particles with an average particle size of 0.2 to 10 μm and a surface area/mass ratio in the range of 0.2 to 3.0 m 2 /g; dispersed in

(b) 4 to 35 wt % organic medium comprising

(1) a resin selected from the group consisting of a phenoxy, urethane, oxazoline, and ester resin dissolved in

(2) organic solvent selected from the group consisting of a dibasic ester, glycol ether, alcohol and mixtures thereof;

(c) 0.25 to 5 wt % reducing agent comprising a hydroxyl containing compound; and

(d) 0.0 to 5 wt % viscosity stabilizing agent comprising a carboxylic acid containing compound or phosphate containing compound;

wherein the wt % are based on the total weight of said polymer thick film copper conductor composition.

2. The polymer thick film copper conductor composition of claim 1 , wherein said copper powder particles are in flake form, said reducing agent is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine and malonic acid and said viscosity stabilizing agent is selected from the group consisting of malonic acid, malic acid, and tartaric acid.

3. A method for forming an electrical conductor in an electrical circuit, comprising:

a) providing a substrate;

b) providing a polymer thick film copper conductor composition comprising the polymer thick film copper conductor composition of claim 1 ;

c) applying said polymer thick film copper conductor composition onto said substrate; and

d) subjecting said polymer thick film copper conductor composition to photonic sintering to form said electrical conductor.

4. The method of claim 3 , said method further comprising a step of drying said polymer thick film conductor composition, wherein said step of drying is carried out following step (c) but before step (d).