NOVELTY - The method comprises providing a substrate having a passivation layer (104) deposited on a first surface of the substrate, forming via/contact holes (107) in the passivation layer deposited on the second surface, and exposing the first surface of the substrate to an etchant, to a first cleaning solution comprising a dilute acid solution to remove a portion of silicon nitride present in the formed via/contact holes and to a second cleaning solution comprising a dilute alkaline solution to remove a portion of aluminum oxide present in the formed via/contact holes.    USE - The method is useful for processing a substrate of a solar cell (claimed) or a photovoltaic cell.    ADVANTAGE - The method is capable of efficiently removing the passivation layer from the surface of substrate of the solar cell and cleaning the via/contact holes and improving contact resistance in rear point contact solar cell thus enhancing the overall efficiency and reliability and reducing manufacturing cost of the solar cell.    DETAILED DESCRIPTION - The method comprises providing a substrate having a passivation layer (104) deposited on a first surface of the substrate, forming via/contact holes (107) in the passivation layer deposited on the second surface, exposing the first surface of the substrate to an etchant, to a first cleaning solution comprising a dilute acid solution to remove a portion of silicon nitride present in the formed via/contact holes and to a second cleaning solution comprising a dilute alkaline solution to remove a portion of aluminum oxide present in the formed via/contact holes, heating the etchant to dissolve first layer of the passvation layer on the first surface, and forming a metal containing layer on a second surface of the substrate. The passivation layer is formed as a layer stack comprising a first layer and a second layer, where the first layer is different from the second layer. The second surface is opposite to the first surface. The etchant has a viscosity of 5-90 Cp, and etchant is heated to a temperature of 30-85 degrees C for 30-60 seconds. The step of exposing the first surface of the substrate to the etchant comprises: applying the etchant onto the first surface of the substrate; spreading the etchant across the entire first surface through a linear and/or circular movement of a roller; pressing the etchant against a printing screen having mesh openings using a soft contact tool; and wiping the etchant across the printing screen to apply the etchant onto the first surface through the mesh openings. The metal containing layer fills the formed via/contact holes, and is present in intimate contact with the underlying surface of the substrate through the via/contact holes. The substrate is exposed to the first cleaning solution at 20 degrees C for 45-70 seconds and to the second cleaning solution at 40-95 degrees C for 30-60 seconds. An INDEPENDENT CLAIM is included for a system for processing a solar cell substrate.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a solar cell having a passivation layer formed on a back surface of a substrate.    Passivation layer (104)    Back contact (106)    Via/contact holes (107)    Front contact (108)    Solar cell substrate. (110)