COPPER AND SILVER INKS FOR INK JET PRINTING

摘要

Organometallic and nanoparticle based inks were evaluated for use in the ink jet printing of copper and silver conducting lines. Pure, smooth, dense, highly conductive coatings were produced with Cu(hfa)*VTMS and Ag(hfa)COD organometallic precursors. Good adhesion to the substrates tested, glass, kapton tape and Si, has been achieved without use of any adhesion promoters. The conductivity of the silver coatings is near the value of bulk silver (2μΩ*cm). The copper coatings had conductivities an order of magnitude less than bulk. Ohmic contacts with contact resistance of 400μΩ*cm~2 were obtained between n-type silicon and silver deposited in air at 400℃, demonstrating the feasibility of an ink jet printing approach to fabrication of silver collector grids on silicon solar cells. We also report some initial results on direct ink jet printing of Ag-based inks. In addition to the organometallic Ag and Cu inks, nanoparticulate precursors were investigated and to date have not yielded coatings with the necessary adhesion strength nor conductivity. Inks comprised of copper particles coupled with the organometallic Cu source have shown improved results.