NOVELTY - Back side contact photovoltaic (PV) cell apparatus comprises a crystalline silicon substrate having a front side for receiving light, a back side opposite the front side, and semiconductor junctions defined by junction-forming regions of a first polarity and junction-forming regions of a second polarity.    USE - Used as back side contact PV cell apparatus.    ADVANTAGE - The apparatus provides a highly efficiency back contact photovoltaic cells. The front side surface has reduced amount of metal diffused into it, where diffusion generally has a detrimental effect on the process of charge recombination in the PV cell.    DETAILED DESCRIPTION - Back side contact photovoltaic (PV) cell apparatus comprises: (a) a crystalline silicon substrate having a front side for receiving light, a back side opposite the front side, and one or more semiconductor junctions defined by one or more junction-forming regions of a first polarity and one or more junction-forming regions of a second polarity; (b) first exposed metal contact portions on the back side and spaced apart in two orthogonal directions across the back side to lie in a first set of rows and columns on the back side, the exposed metal contact portions are electrically connected on the substrate to the junction-forming regions of the first polarity to associate the columns of the first set with the first polarity; and (c) second exposed metal contact portions spaced apart in the two orthogonal directions across the back side to lie in a second set of rows and columns on the back side and so that substantially all of the columns of the second set are between adjacent columns of the first set, and where the exposed metal contact portions are electrically connected on the substrate to the junction-forming regions of the second polarity, so that the second set of columns of the exposed metal contact portions is associated with the second polarity, where the adjacent columns of the exposed metal contact portions on the back side are of opposite polarity to facilitate connection of parallel spaced apart electrical conductors on an electrode on the back side to respective columns to connect the PV cell to an electrical circuit. INDEPENDENT CLAIMS are included for:    (1) a method of making a back side contact PV cell;    (2) a method of connecting a first PV cell to an electrical circuit;    (3) a method of making an electrode for interconnecting back contact PV cells in a series string;    (4) a method of making a string of PV cells; and    (5) an electrode for interconnecting back contact PV cells in a series string.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a back contact photovoltaic cell.    Substrate (12)    Front side (14)    Back side (16)    Grid lines (30,31,32,33,34,35)    Mask (40)    Exposed metal contact portion (46)