Silver electroplating compositions and methods for electroplating rough matt silver
Silver electroplating compositions deposit rough, matt silver having needle-like grain structures. The rough, matt, silver deposits enable good adhesion with dielectric materials, even in environments of high relative humidity.
1. A silver electroplating composition comprising silver ions, a conductivity compound and a compound having a formula:
wherein R 1 is hydrogen or C 1 -C 4 alkyl and R 2 is C 1 -C 4 alkyl or phenyl.
2. The silver electroplating composition of claim 1 , wherein the compound is selected from the group consisting of 6-(dibutylamino)-1,3,5-triazine-2,4-dithiol, 6-anilino-1,3,5-triazine-2,4-dithiol and mixtures thereof.
3. The silver electroplating composition of claim 1 , wherein the compound is in amounts of at least 1 ppm.
4. The silver electroplating composition of claim 1 , wherein the conductivity compound comprises potassium dihydrogen phosphate, potassium phosphate, sodium phosphate, ammonium phosphate, sodium nitrate, organic acids, inorganic acids or mixtures thereof.
5. The silver electroplating composition of claim 1 , further comprising a buffering agent.
6. The silver electroplating composition of claim 1 , further comprising a pH adjusting agent.
7. The silver electroplating composition of claim 1 , further comprising a silver complexing agent.
8. The silver electroplating composition of claim 1 , further comprising an organic solvent chosen from pyridine and pyridine compounds.
9. The silver electroplating composition of claim 8 , wherein the pyridine compound consists of 2-pyridinemethanol, 3-pyridinemethanol, 2-pyridineethanol, 3-pyridineethanol, and mixtures thereof.
10. The silver electroplating composition of claim 1 , wherein a pH of the silver electroplating composition is 6-14.
11. A method of electroplating rough, matt silver on a substrate comprising:
a) providing the substrate;
b) contacting the substrate with the silver electroplating composition of claim 1 ; and
c) applying an electric current to the silver electroplating composition and substrate to electroplate a rough, matt silver deposit on the substrate.
12. The method of claim 11 , wherein the rough, matt silver deposit comprises a Sa of 0.1-0.4 μm and an Sdr of 5-50%.
13. The method of claim 11 , wherein the rough, matt silver deposit has needle-like structures comprising a peak height of 1-4 μm and a peak base of 0.2-0.4 μm.
14. The method of claim 11 , wherein a current density is 10 ASD to 180 ASD.