TECHNOLOGY FOCUS - ELECTRONICS - Preferred Method: The gridline is formed on only one or two opposite side of the substrate. The method further involves sintering the conductive ink. Preferred Components: The gridline has a width of 10-100 (preferably 10-75) microns and a thickness of 25-200 (preferably 25-100) microns. The gridline has an aspect ratio of 0.3-15 (preferably 0.4-10). The substrate is a semiconductor substrate having a p-type region and an n-type region. The substrate has tipper surface and a lower surface, the at least one gridline being formed on the upper surface, and a metal contact is formed on the lower surface. The solar cell structure further comprises a bus bar formed on the upper surface; and a clear material over the gridlines. The upper surface further comprises a textured surface or an antireflection material coated on it. The sintering burns-off the sacrificial material. The clear material is selected from glass sheet, a plastic sheet, plastic encapsulation, and spin-on glass.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal particles are particles of a metal selected from aluminum, palladium, silver, platinum, gold, copper, nickel, their alloys, and their oxide precursors (preferably aluminum and silver). The metal particles are in the form of spherical particles, potato-shaped particles, flakes, or slivers. The metal particles (preferably 50% metal particles) have an average major dimension of 0.05-20 (preferably 1) microns. The metal particles comprise particles in the form of flakes. The metal particle flakes have an average major dimension of 0.5-20 microns. The metal particles comprise metal flakes, and metal spherical particles (5-40 wt.%) having an average particle size of 50-200 nm. The metal particle further comprises metal spherical particles having an average particle size of 1-15 microns. The material set further comprises an organometallic compound or metal resinate; thixotropic agent selected from hydrogenated castor oil and its derivatives, non-hydrogenated castor oil and its derivatives and ethyl cellulose. The electronic glass is selected from lead oxide/zinc oxide glass, silica glass, titanium oxide glass, boric oxide glass, zirconium glass, silica/bismuth oxide/lead oxide, boric oxide/silica/bismuth oxide, bismuth oxide/silica/zinc oxide, and/or bismuth oxide/silica/lead oxide. The electronic glass is a lead-free glass. The sintering inhibitor is selected from oxides of rhodium, oxides of ruthenium, and rhodium- and ruthenium-based compounds that, under the firing conditions which they are subjected to, are changed to oxides of the metal (preferably ruthenium metal, ruthenium oxide, ruthenium-based pyrochlore compounds, ruthenium resonates, and/or ruthenium (II) oxide. The substrate is a silicon substrate. The substrate is formed from a semiconductor material selected from aluminum arsenide, aluminum gallium arsenide, boron nitride, cadmium sulfide, cadmium selenide, copper indium gallium selenide, diamond, gallium arsenide, gallium nitride, germanium, indium phosphide, silicon, silicon carbide, silicon nitride, silicon germanium, silicon on insulator, zinc sulfide, and zinc selenide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The solvent is selected from kerosene, mineral spirits, terpineol, esters of phthalic acid, butyl carbitol, butyl carbitol acetate, hexylene glycol, aliphatic di-esters, high-boiling alcohols and/or alcohol esters. The thixotropic agent is selected from hydrogenated castor oil and its derivatives, non-hydrogenated castor oil and its derivatives, and ethyl cellulose. The optional additives are selected from thixotropic agents, gelling agents, plasticizers, co-solvents, wetting agents, and viscosity modifiers or builders. The solvent has a boiling point of 130-350 degrees C. The sintering inhibitor is in a form of separate particulates, organometallic compounds that are soluble in the organic component, or a coating on the metal particles.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The sacrificial feedstock further comprises a thixotropic agent. The sacrificial feedstock and organic compound comprises solvent (25-99%), plasticizer or co-solvent (0-40%), organic polymer (1-30%), and other additives (0-10%). The sacrificial feedstock is an unfilled material having less than or equal to 2% by volume of discrete solid or gel-like particles. The material set comprises (%) metal particles (50-90), electronic glass (1-10), and organic component (5-40). The functional material further comprises a sintering inhibitor. The sacrificial material burns out during a sintering process of the functional material at 600-800 degrees C for a time period of less than one minute. The sacrificial feedstock completely burns out during the sintering process. The functional material in the ribbon in its unfired state has a width of 10-100 (preferably 10-75) microns and a thickness of 25-200 (preferably 25-100) microns. Preferred Components: The sacrificial feedstock has viscosity of less than or equal to 5 times a viscosity of the functional material at a shear rate of greater than 100 sec-1. The sacrificial feedstock has at least one rheological property that is substantially the same as the same rheological property of the functional material; or lower that the same rheological properties of the functional material. The rheological property is selected from shear and extensional viscosity, the loss and storage modulus, the primary and secondary normal stress coefficient, the elastic flow relaxation time, the flow consistency index, the flow behavior index, the yield stress, and the surface tension. The functional material is selected from conductive material, material comprising semiconductor dopant, a photoresist material, and a ceramic material; and conductive ink or conductive ink precursor composition comprises metal particles, an electronic glass, an organic component, and at least one optional additives. The sacrificial material comprises solvent, organic polymer, and at least one optional additives selected from thixotropic agents, gelling agents, plasticizers, co-solvents, wetting agents, and viscosity modifiers or builders. The organic polymer is selected from ethyl cellulose, ethylhydroxyethyl cellulose, wood rosin, mixtures of ethyl cellulose and phenolic resins, polymethacrylates of lower alcohols, and/or monobutyl ether of ethylene glycol monoacetate. The ribbon is extrudable onto a substrate and the sacrificial feedstock maintains the functional material in place with an aspect ratio of greater than 0.3 prior to removal of the sacrificial feedstock. The sacrificial feedstock is of substantially the same composition as the functional material, except that the sacrificial feedstock is substantially free of conductive metal particles and electronic glass. The extruded ribbon is a coextruded ribbon. The sacrificial material is of substantially the same composition as the functional material, except that conductive metal particles and electronic glass are excluded from the sacrificial material. The functional material in its unfired state has an aspect ratio of 0.4-10. Preferred Method: The sacrificial feedstock can be removed from the ribbon, leaving the functional material in place with an aspect ratio of 0.4-10. The sacrificial feedstock is removable from ribbon by a process that maintains functional properties of the functional material. The sacrificial feedstock is removable from the ribbon by a process selected from pyrolysis, burning, dissolution, dispersion, and washing. The sacrificial material is extruded on only one or on two opposite sides of the functional material. The sacrificial material is coextruded with the functional material. The method (P1) further involves sintering the functional material. The sintering burns-off the sacrificial material. The sintering is at 600-800 degrees C for a time period of less than one minute. The sintering is conducted under normal atmosphere or under an inert atmosphere. EXAMPLE - A sacrificial feedstock comprising (wt.%) Texanol (RTM: 2,2,4-trimethyl-1,3-pentanediol 1-monoisobutryate) (65), dibutyl phthalate (22), ethyl cellulose (12), and Thixatrol ST (RTM: castor wax gelling agent) (1) was prepared.