Provided is a polishing composition with which surface defects can be efficiently reduced. This invention provides a polishing composition comprising a water-soluble polymer M.sub.C-end. The main chain of the water-soluble polymer M.sub.C-end is formed with a non-cationic region as its main structural part and a cationic region located at least at one end of the main chain. The cationic region has at least one cationic group.

Provided is a polishing composition with which surface defects can be efficiently reduced. This invention provides a polishing composition comprising a water-soluble polymer M.sub.C-end. The main chain of the water-soluble polymer M.sub.C-end is formed with a non-cationic region as its main structural part and a cationic region located at least at one end of the main chain. The cationic region has at least one cationic group.

A silicon carbide substrate is composed of silicon carbide, and when a main surface thereof is etched with chlorine gas, the overall length of linear etch-pit groups observed in the main surface is equal to or less than the diameter of the substrate.

A silicon carbide substrate is composed of silicon carbide, and when a main surface thereof is etched with chlorine gas, the overall length of linear etch-pit groups observed in the main surface is equal to or less than the diameter of the substrate.

Provided are a polishing method that can be commonly applied to different types of silicon substrates varying in resistivity as well as a polishing composition set used in the polishing method. The silicon substrate polishing method provided by this invention comprises supplying a first polishing slurry S.sub.1 and a second polishing slurry S.sub.2 to a silicon substrate to be polished, switching them in this order midway through polishing the silicon substrate. The first polishing slurry S.sub.1 comprises an abrasive A.sub.1 and a water-soluble polymer P.sub.1. The polishing removal rate of the first polishing slurry S.sub.1 is higher than that of the second polishing slurry S.sub.2.

A carrier head for a chemical mechanical polishing apparatus comprises: a base; a substrate receiving member comprising a plate portion having an outer surface for receiving a substrate and an inner surface at the back of the outer surface, a perimeter portion extended in a height direction from an edge of the plate portion, a securing portion extended from an outer part of the perimeter portion and connected to a lower part of the base, and a contact portion extended from an inner part of the perimeter portion; a contact coupling structure connected to the lower part of the base to provide a contact surface to the contact portion; and a perimeter portion pressurizing chamber formed by taking the securing portion and the contact portion as chamber walls when the contact portion contacts firmly the contact coupling structure by means of fluid pressure.

A two component composition for making chemical mechanical polishing pad for polishing a semiconductor substrate is provided comprising a liquid aromatic isocyanate component having an unreacted isocyanate (NCO) concentration of from 15 to 40 wt. %, based on the total solids weight of the aromatic isocyanate component, such as methylene di(phenylisocyanate) (MDI), a liquid polyol component of a polyol having a polyether backbone and having from 5 to 7 hydroxyl groups per molecule, and a curative of one or more polyamine or diamine, wherein the reaction mixture comprises 50 to 65 wt. % of hard segment materials, based on the total weight of the reaction mixture. The composition when mixed cured to form a polyurethane reaction product. Also provided are CMP polishing pads made from the polyurethane reaction product by spraying the composition into a mold.

Provided is a polishing composition capable of keeping a good polishing removal rate stably. The polishing composition includes silica particles as abrasives and a basic compound as a polishing removal accelerator. The silica particles have a density of silanol groups that is 1.5 to 6.0 pieces/nm.sup.2. The polishing composition has an adsorption ratio parameter A that is 1.2 or less, the adsorption ratio parameter representing concentration dependency of an amount of adsorption of the basic compound to the silica particles as the ratio of high-concentration adsorption amount/low-concentration adsorption amount.

Provided is a polishing composition capable of keeping a good polishing removal rate stably. The polishing composition includes silica particles as abrasives and a basic compound as a polishing removal accelerator. The silica particles have a density of silanol groups that is 1.5 to 6.0 pieces/nm.sup.2. The polishing composition has an adsorption ratio parameter A that is 1.2 or less, the adsorption ratio parameter representing concentration dependency of an amount of adsorption of the basic compound to the silica particles as the ratio of high-concentration adsorption amount/low-concentration adsorption amount.

Provided are a method for polishing a silicon substrate according to which PID can be reduced and a polishing composition set usable in the polishing method. The silicon substrate polishing method provided by this invention comprises a stock polishing step and a final polishing step. The stock polishing step comprises several stock polishing sub-steps carried out on one same platen. The several stock polishing sub-steps comprise a final stock polishing sub-step carried out while supplying a final stock polishing slurry P.sub.F to the silicon substrate. The total amount of the final stock polishing slurry P.sub.F supplied to the silicon substrate during the final stock polishing sub-step has a total weight of Cu and a total weight of Ni, at least one of which being 1 ?g or less.