TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The rheological modifier comprises at least one of: (i) micronized amide wax, (ii) silica, (iii) silica and clay, (iv) talc, and (v) talc and clay. The composition further comprises at least one of: (i) one or more inorganic fillers, (i) a colorant pigment or dye, and (iii) an optical brightener. Rheological modifier comprises a derivative of an unsaturated oil or triglyceride. The derivative of an unsaturated oil or triglyceride is an epoxidized, maleated or fumarated derivative of the unsaturated oil or triglyceride; or the derivative of an unsaturated oil or triglyceride is a modified castor oil. Rheological modifier includes a hydrocarbon or amide or polyamide wax. The etch resist is the composition of matter. Preferred Composition: The organic compounds include one of: (i) 1.0% to 40% vinyl acetate copolymer and 5.0% to 50% phenolic novolac, and (ii) 5.0 to 15% vinyl acetate copolymer and 15 to 25% phenolic novolac; or the organic compounds include one of: (i) 0.1% to 30% shellac resin; 0.10% to 50% phenolic resin; 0.10% to 75% partially isobutylated melamine resin; 0.10% to 50% maleic modified rosin ester, and (ii) 1.0 to 10% shellac resin; 15% to 25% phenolic resin; 1.0 to 5.0% partially isobutylated melamine resin; and 2.0 to 8.0% maleic modified rosin ester. One or more solvents include one of: (i) 5%-30% ethylene glycol monobutyl ether and 10%-40% diethylene glycol mono ethyl ether acetate, and (ii) 15-20% ethylene glycol monobutyl ether and 25-30% diethylene glycol mono ethyl ether acetate. One or more solvents include one of: (i) 5%-35% ethylene glycol monobutyl ether and 5%-25% diethylene glycol butyl ether, and (ii) 20-25% ethylene glycol monobutyl ether and 10-15% ethylene glycol butyl ether. One or more solvents include one of: 5%-30% diethylene glycol monoethyl ether and 10%-40% diethylene glycol mono ethyl ether acetate, and (ii) 15-20% diethylene glycol monoethyl ether and 25-30% diethylene glycol mono ethyl ether acetate. The rheological modifier includes one of: (i) 0.1% to 12% organoclay rheological additive; 2.0% to 35% uncoated talc; and 0.1% to 15% of an amide wax rheological modifier or micronized amide wax rheological modifier, and (ii) 1.0 to 5.0% organoclay rheological additive; 10 to 15% uncoated talc; and 3.0 to 6.0% amide wax rheology modifier or micronized amide wax rheological modifier. It includes one of: (i) 1.0 to 30% talc; 1.0% to 40% fumed silica; and 0.1% to 15% polyacrylate flow aid; and (ii) 20 to 25% talc; 5.0% to 15% fumed silica; and 1.0% to 5.0% polyacrylate flow aid. The organic compounds include 5-20% vinyl acetate copolymer and 10-30% phenolic novolac. The unsaturated oil or triglyceride is present at 2.5-5%, and comprises micronized amide wax. The hydrocarbon or amide or polyamide wax is present at one of (i) 0.1% to 25%, and (ii) 1-10%. Preferred Parameters: The composition of matter is sufficiently shear thinning, and has the rheology and viscosity to be screen-printable. The solvent or solvents are sufficiently high boiling so as to have screen stability. Preferred Process: Opening insulating layer on the back surface of silicon solar cell for contact further involves selectively etching the silicon by a second wet etch. Etching is performed using a conventional wet etch process.