Abstract: Silica sols exhibiting desirable yield-dilatancy are fabricated. A mixture comprising silica, water, and a pH-adjusting agent is provided, and the mixture is shear-mixed. The desirable properties of the resultant sol are attained by using a concentration of pH-adjusting agent that provides a viscosity within a particular range during shear mixing. The requisite pH range, however, changes depending on the properties of the silica mixture. A discovered technique for determining this changing pH range is by selecting the pH based on the silica surface area per unit volume of the mixture.

Abstract: The invention reflects discovery of a liquid phase doping technique that, unlike previous techniques, exhibits very little fluorine depletion upon subsequent heating. The invention involves the steps of providing a silica sol comprising a tetraalkylammonium hydroxide and a di-, tri-, or tetraalkylammonium fluoride, the sol having pH of about 10 to about 14, adding a gelling agent to the sol to induce gelation, casting or extruding the sol to form a gel body, and then drying, heat treating, and sintering the body. Advantageously, the fluorine-containing compound is tetramethylammonium fluoride.

Abstract: A process for enhancing the performance of resist polymers in lithographic processes for device fabrication is disclosed. The resist polymers contain acid labile functional groups. When these functional groups are removed and replaced by hydrogen, the polymer becomes more soluble in the aqueous base developer solutions used in lithographic processes. A portion of the acid-labile functional groups are cleaved from the polymer to obtain a resist polymer with increased sensitivity, improved adhesion, and reduced film shrinkage during post-exposure bake. The acid labile functional groups are cleaved by dissolving the polymer in a suitable solvent and subjecting the mixture to increased temperature until the desired number of acid labile functional groups are cleaved from the polymer. The polymer is then recovered from the mixture and employed as a resist in a lithographic process for device fabrication.

Abstract: Recovery of germanium from the effluent of optical fiber manufacturing processes depends on the realization that the germanium is to a substantial extent in gaseous form. Thus, to separate the germanium effectively appropriate measures are taken to separate not only particulate matter but also gaseous germanium compounds. This separation is done through among other steps an appropriate solvation and precipitation to remove the gaseous germanium material.