NOVELTY - Composition of matter suitable for use as an etch or plating resist in a process for manufacturing passivated emitter rear contact (PERC) solar cells, comprises organic compounds comprising any of the following, or combinations of the following: a phenol-formaldehyde resin; a vinyl acetate polymer or copolymer; a rosin resin or a modified rosin resin; a rosin polyester; a gum rosin or a modified ester of a gum rosin; shellac; melamine or modified melamine resin, cyclized rubber, Gilsonite or uintahite resin; one or more solvents; and a rheological modifier.    USE - The composition of matter is useful as etch or plating resist in a process for manufacturing PERC solar cell; and for opening insulating layer on the back surface of silicon solar cell for contact (all claimed).    ADVANTAGE - Improved methods are provided for fabricating rear-passivated solar cells that overcome the problems of conventional approaches, such as laser ablation.    DETAILED DESCRIPTION - Composition of matter suitable for use as an etch or plating resist in a process for manufacturing passivated emitter rear contact (PERC) solar cells, comprises organic compounds comprising any of the following, or combinations of the following: a phenol-formaldehyde resin, such as a novolac resin or a resol; a vinyl polymer or copolymer; a vinyl acetate polymer or copolymer; a rosin resin or a modified rosin resin, such as a maleic, fumaric, phenolic, or otherwise modified rosin or rosin ester; a rosin polyester; a gum rosin or a modified ester of a gum rosin; shellac; melamine or modified melamine resin, cyclized rubber, Gilsonite or uintahite resin; one or more solvents; and a rheological modifier. INDEPENDENT CLAIMS are included for:    (1) a method of fabricating a PERC cell, involving printing any of the compositions of matter as an etch resist onto a silicon solar cell wafer, wet etching the wafer, and performing an etch resist removal process on the wafer; and    (2) a method for opening an insulating layer on the back surface of a silicon solar cell for contact, involving depositing a screen printable etch resist on the rear surface; etching the insulating/passivation layer; and removing the etch resist through a spray or liquid immersion process.