A method comprises rubbing a powder comprising titanium dioxide particles against a surface of an aluminum substrate to form a layer bonded to the surface of the aluminum substrate. The powder comprises titanium dioxide and is essentially free of organic particles. Composite articles preparable by the method are also disclosed.

Methods for fabricating a chemical-mechanical polishing composition include growing colloidal silica abrasive particles in a liquid including an aminosilane compound such that the aminosilane compound becomes incorporated in the abrasive particles. A dispersion including such colloidal silica abrasive particles may be further processed to obtain a chemical-mechanical polishing composition including colloidal silica particles having the aminosilane compound incorporated therein.

Methods for fabricating a chemical-mechanical polishing composition include growing colloidal silica abrasive particles in a liquid including an aminosilane compound such that the aminosilane compound becomes incorporated in the abrasive particles. A dispersion including such colloidal silica abrasive particles may be further processed to obtain a chemical-mechanical polishing composition including colloidal silica particles having the aminosilane compound incorporated therein.

The present invention provides aqueous chemical mechanical planarization (CMP) polishing compositions have excellent heat aging and shelf stability in the form of concentrates comprising a mixture of a compound containing two quaternary ammonium groups, such as hexabutyl C.sub.1-C.sub.8 alkanediammonium dihydroxides or salts thereof, preferably N,N,N,N′,N′,N′-hexabutyl-1,4-butanediammonium dihydroxide (HBBAH), and aminosilane group containing silica particles in the amount of from 1 to 30 wt. % or, preferably, from 15 to 22 wt. %, as solids based on the total weight of the composition, the composition having a pH ranging from 3 to 5 or, preferably, from 3.5 to 4.5 wherein the composition is stable against visible precipitation or sedimentation at a 15 wt. % solids content after heat aging at a temperature of 45° C. for at least 6 days.

The present invention provides aqueous chemical mechanical planarization (CMP) polishing compositions have excellent heat aging and shelf stability in the form of concentrates comprising a mixture of a compound containing two quaternary ammonium groups, such as hexabutyl C.sub.1-C.sub.8 alkanediammonium dihydroxides or salts thereof, preferably N,N,N,N′,N′,N′-hexabutyl-1,4-butanediammonium dihydroxide (HBBAH), and aminosilane group containing silica particles in the amount of from 1 to 30 wt. % or, preferably, from 15 to 22 wt. %, as solids based on the total weight of the composition, the composition having a pH ranging from 3 to 5 or, preferably, from 3.5 to 4.5 wherein the composition is stable against visible precipitation or sedimentation at a 15 wt. % solids content after heat aging at a temperature of 45° C. for at least 6 days.

A method of grinding a semiconductor nanocrystal-polymer composite, the method including obtaining a semiconductor nanocrystal-polymer composite including a semiconductor nanocrystal and a first polymer, contacting the semiconductor nanocrystal-polymer composite with an inert organic solvent; and grinding the semiconductor nanocrystal-polymer composite in the presence of the inert organic solvent to grind the semiconductor nanocrystal-polymer composite.

A workpiece to be ground by a grinding wheel of a grinding apparatus has a first layer including a first material and a second layer including a second material that is harder to grind than the first material and stacked on the first layer. The rotational speed of the grinding wheel for grinding the second layer, i.e., a second rotational speed, is lower than the rotational speed of the grinding wheel for grinding the first layer, i.e., a first rotational speed. The second layer can thus be ground effectively, as it is not necessary to use a grinding wheel with a high grinding capability or to lower a rate at which the workpiece is ground. Consequently, it is possible to maintain productivity for device chips manufactured by dividing the workpiece, and also prevent the footprint of the grinding apparatus from increasing.

The present disclosure provides a precision calibrating device and a precision calibrating method for a magnetorheological polishing device, which realize an automatic and quick calibration process. It is ensured that a polishing gap is kept within an allowable error range when the magnetorheological polishing device processes surfaces of different optical elements, thereby effectively controlling a removal function, reducing or eliminating surface residual errors after processing and low frequency errors and medium frequency errors introduced by insufficient trajectory precision of a mechanical arm, and improving a processing precision of the magnetorheological polishing device based on the mechanical arm.

A wafer processing method includes a first grinding step and a second grinding step. In the first grinding step, first grinding abrasives are moved in a processing feed direction that is a direction orthogonal to a holding surface of a chuck table of grinding apparatus and a wafer is ground to form a first circular recess in the back surface of the wafer. In the second grinding step, second grinding abrasives formed of finer abrasive grains than the first grinding abrasives are moved down in an oblique direction from the center side of the wafer toward the periphery of the wafer and the first circular recess is ground.

A wafer processing method includes a first grinding step and a second grinding step. In the first grinding step, first grinding abrasives are moved in a processing feed direction that is a direction orthogonal to a holding surface of a chuck table of grinding apparatus and a wafer is ground to form a first circular recess in the back surface of the wafer. In the second grinding step, second grinding abrasives formed of finer abrasive grains than the first grinding abrasives are moved down in an oblique direction from the center side of the wafer toward the periphery of the wafer and the first circular recess is ground.