Provided is a polishing liquid that is used when one surface of a wafer is polished by use of a fixed abrasive grain polishing pad with abrasive grains fixed in the pad, in which an organic salt that exhibits a basic property by hydrolysis and contains no metal and an organic base that contains no metal are dissolved, and no abrasive grains are contained. Preferably, the organic salt includes a strong basic cation and a weak acidic anion, and the organic base contains at least one of ammonia, an amine, and a basic amino acid.

A carrier for a double-side polishing apparatus configured to double-side polish providing a semiconductor silicon wafer. The carrier being disposed between upper and lower turn tables have a polishing pad attached, and includes a holding hole formed to hold the semiconductor silicon wafer between the upper and lower turn tables during polishing. The carrier for a double-side polishing apparatus is made of a resin. An average contact angle with pure water of front and back surfaces of the carrier, which come into contact with the polishing pads, is 45° or more and 60° or less, and a difference in average contact angles between the front surface and the back surface is 5° or less, which provides a carrier for a double-side polishing apparatus capable of enhancing the polishing rate for a semiconductor silicon wafer by using a resinous carrier; and a double-side polishing apparatus and method which employ the carrier.

A method for polishing a germanium wafer having a surface composed of germanium, including: adding aqueous hydrogen peroxide to a first polishing slurry of an aqueous alkaline solution containing colloidal silica to make a second polishing slurry, and polishing the surface of the germanium wafer by using the second polishing slurry; wherein the aqueous hydrogen peroxide is added to the first polishing slurry in a concentration such that 30 wt % aqueous hydrogen peroxide is added in a volume of more than 0 vol % and 0.1 vol % or less based on the volume of the first polishing slurry, and the polishing is performed by using the second polishing slurry. A method for polishing a germanium wafer that can make the surface roughness of a polished Ge surface be sufficiently small, and can sufficiently suppress generation of interface defects such as voids and blisters when used for a wafer to be bonded.

Provided is a method for filtering an additive-containing liquid that can achieve a polishing composition exhibiting excellent defect reducing capability while maintaining a practical filter life. The method for filtering a polishing additive-containing liquid provided by the present invention includes the step of: filtering the polishing additive-containing liquid with a filter that satisfies the following conditions (1) and (2). (1) The average pore diameter P measured by a palm porometer is 0.15 μm or less. (2) The pore diameter gradient (S.sub.in/S.sub.out), which is the ratio of the inlet-side average pore diameter (SO to the outlet-side average pore diameter (S.sub.out), both diameters being measured through observation with an SEM, is 3 or less.

A silicon carbide substrate has a first main surface, and a second main surface opposite to the first main surface. A region including at least one main surface of the first and second main surfaces is made of single-crystal silicon carbide. In the one main surface, sulfur atoms are present at not less than 60×10.sup.10 atoms/cm.sup.2 and not more than 2000×10.sup.10 atoms/cm.sup.2, and carbon atoms as an impurity are present at not less than 3 at % and not more than 25 at %. Thereby, a silicon carbide substrate having a stable surface, a semiconductor device using the substrate, and methods for manufacturing them can be provided.

A polishing system for polishing a semiconductor wafer includes a wafer support for holding the semiconductor wafer, and a first polishing pad for polishing a region of the semiconductor wafer. The semiconductor wafer has a first diameter, and the first polishing pad has a second diameter shorter than the first diameter.

A metallic abrasive pad for use in a smoothing operation applied to a worked surface of a workpiece by a catalyst-supported chemical machining method, the metallic abrasive pad including a compression-formed compact of one or more metal fibers made of a transition-metal catalyst, wherein a contact spot of the one or more metal fibers intersecting each other is sintered, the one or more metal fibers are fixed to each other, and the metallic abrasive pad has a prescribed void ratio.

The present invention provides a polishing composition for use in polishing a material having a Vickers hardness of 1500 Hv or higher. The polishing composition has an oxidation-reduction potential ORP.sub.x mV and the material to be polishing has an oxidation-reduction potential ORP.sub.y mV, with their relation satisfying ORP.sub.x−ORP.sub.y≧100 mV.

Described is a use of a chemical-mechanical polishing (CMP) composition for polishing a substrate or layer containing one or more lll-V materials, wherein the chemical-mechanical polishing (CMP) composition comprises the following components: (A) surface modified silica particles having a negative zeta potential of −15 mV or below at a pH in the range of from 2 to 6 (B) one or more constituents selected from the group consisting of (i) substituted and unsubstituted triazoles not having an aromatic ring annealed to the triazol ring, (ii) benzimidazole, (iii) chelating agents selected from the group consisting of amino acids with two or more carboxyl groups, aliphatic carboxylic acids, and the respective salts thereof, and (iv) homopolymers and copolymers of acrylic acid, and the respective salts thereof, (C) water (D) optionally one or more further constituents, wherein the pH of the composition is in the range of from 2 to 6.

A method for effectively removing minute impurities of 1 μm or less in size that are present on a surface of an aluminum nitride single-crystal substrate without etching the surface includes scrubbing a surface of an aluminum nitride single-crystal substrate using a polymer compound material having lower hardness than an aluminum nitride single crystal, and an alkali aqueous solution having 0.01-1 mass % concentration of potassium hydroxide or sodium hydroxide, the alkali aqueous solution being absorbed in the polymer compound material.