NOVELTY - Back-contact solar cell is made by forming holes extending from a front surface of a semiconductor substrate to a rear surface of the substrate, depositing a patterned dielectric layer on the rear surface; alloying contacts with the substrate; disposing a first conductive grid on the dielectric layer in electrical contact with the contacts; and disposing a second conductive grid on the rear surface in electrical contact with the diffusion.    USE - For making a back-contact solar cell.    ADVANTAGE - Increases efficiency by minimizing p-type contact areas and maximizing n-type doped regions on the rear surface of the p-type substrate. It provides manufacturing processes with fewer, more economical process steps that produce high efficiency solar cells.    DETAILED DESCRIPTION - Making a back-contact solar cell comprises forming holes extending from a front surface of a semiconductor substrate to a rear surface of the substrate, where the substrate comprising a first conductivity type; providing a diffusion comprising an opposite conductivity type on the front surface, the rear surface, and on surfaces enclosing the holes; depositing a patterned dielectric layer on the rear surface; alloying contacts comprising the first conductivity type with the substrate; disposing a first conductive grid on the dielectric layer in electrical contact with the contacts; and disposing a second conductive grid on the rear surface in electrical contact with the diffusion.    An INDEPENDENT CLAIM is also included for a back-contact solar cell comprising a substrate comprising a first conductivity type; a diffusion comprising an opposite conductivity type on portions of a rear surface of the substrate; a screen printed dielectric layer on the rear surface; openings in the dielectric layer, where regions of the rear surface exposed through the openings comprise the first conductivity type; conductive contacts disposed in the openings; and gridlines electrically connected to the contacts, the gridlines comprising a width greater than a width of the openings.    DESCRIPTION OF DRAWING(S) - The figure shows a generic back-contact solar cell, highlighting only features on the back surface.