NOVELTY - Forming a photovoltaic cell electrode structure, where the cell comprising a semiconductor substrate (10) having a passivation layer (30) involves providing several of contact openings through the passivation layer to the substrate; selectively plating a contact metal into the contact openings to deposit the contact metal by printing electroless plating solution directly into the openings; depositing at least one metal containing layer over the deposited contact metal to form metal gridlines; and firing the deposited contact metal and the deposited metal containing layer.    USE - For forming photovoltaic cell electrode structure (claimed). Also useful for forming multiple-layer electrode structures for silicon photovoltaic cells such as silicon solar cells.    ADVANTAGE - The method provides inline process which reduces manufacturing costs; provides silicon solar cells having low contact resistance with a small contact area, thus improved contact resistivity over electrode structures formed with the use of glass frit; is able to provide reduced environmental concerns compared to the use of lead-based glass frit. The method is rapid, cost efficient and less complex method, which provides low contact resistance, low contact area, high conductivity, high solderability, and high stability from solar exposure.    DETAILED DESCRIPTION - Forming a photovoltaic cell electrode structure, where the cell comprising a semiconductor substrate (10) having a passivation layer (30) involves providing several of contact openings through the passivation layer to the substrate; selectively plating a contact metal into the contact openings to deposit the contact metal by printing electroless plating solution directly into the openings; depositing at least one metal containing layer over the deposited contact metal to form metal gridlines; and firing the deposited contact metal and the deposited metal containing layer. The method further involves forming a buffer layer over the deposited contact metal prior to depositing the metal containing layer. The depositing at least one metal containing layer over the deposited contact metal comprises screen printing, extrusion, pad printing, jet printing or dispensing a metal containing paste over the deposited contact metal layer. The method further involves depositing a light sensitive seed layer on the passivation layer prior to forming the contact openings in the passivation layer, and light activating the seed layer in portions on and surrounding at least one of the contact openings, where the selective plating of the contact metal deposits the contact metal at light activated portions of the seed layer and in the contact openings. The seed layer comprises organometallic material. INDEPENDENT CLAIMS are included for following:    (1) an inline system for forming a photovoltaic cell electrode structure comprising a contact opening forming device for providing contact openings through the passivation layer to the semiconductor substrate, a printing device, located downstream from the contact opening forming device, for selectively printing electroless plating solution directly into the contact openings to form contact metal in the contact openings, a heating device to heat the substrate following the printing by the printing device, metallic gridline deposition device, located downstream from the heating device, for depositing metallic gridlines over the contact metal, and a furnace device for firing the metallic gridlines and the substrate with the contact metal, where the inline system retains the photovoltaic cell electrode structure within the system during processing by the foregoing devices; and    (2) forming metal-based pattern on a substrate involving providing a substrate; selectively printing electroless plating solution onto the substrate in image-wise fashion; heating the substrate to activate the printed electroless plating solution.    DESCRIPTION OF DRAWING(S) - The figure shows view of method of forming multiple-layer electrode structure.    Semiconductor substrate (10)    Emitter layer (20)    Passivating layer (30)