In a method of polishing a silicon wafer, a final polishing step includes an upstream polishing step and a subsequent finish polishing step. In the upstream polishing step, as a polishing agent, a first alkaline aqueous solution containing abrasive grains with a density of 110.sup.14/cm.sup.3 or more is first supplied, and the supply is then switched to a supply of a second alkaline aqueous solution containing a water-soluble polymer and abrasive grains with a density of 510.sup.13/cm.sup.3 or less. In the finish polishing step, as a polishing agent, a third alkaline aqueous solution containing a water-soluble polymer and abrasive grains with a density of 510.sup.13/cm.sup.3 or less is supplied. Thus, the formation of not only PIDs but also scratches with small depth can be suppressed.

A slurry comprises abrasive grains, a glycol, and water, wherein an average particle diameter of the abrasive grains is 120 nm or smaller, and a pH is 4.0 or higher and lower than 8.0. A polishing method comprises a step of polishing a metal by use of the slurry.

To planarize a substrate having irregularities on its surface. Provided is a method of chemical mechanical polishing of a substrate. The method includes the step of polishing the substrate using a processing solution, and the step of changing concentration of an effective component in the processing solution, which contributes to the polishing of the substrate.

A chemical mechanical polishing apparatus includes: supply pipes to which a slurry stock solution and a diluent are supplied; flow rate control units, respectively disposed on the supply pipes to control flow rates of the slurry stock solution and the diluent; a mixer connected to the flow rate control units and configured to mix the slurry stock solution and the diluent, supplied from the supply pipes, to prepare a slurry; a slurry storage unit connected to the mixer and configured to store the slurry prepared in the mixer; a slurry supply unit configured to draw out the slurry stored in the slurry storage unit and to supply the slurry to a polishing pad; and a control unit configured to control the flow rate control units to control a mixing ratio of the slurry stock solution and the diluent and a flow rate of the slurry to the polishing pad.

In a method of polishing a silicon wafer, a final polishing step includes an upstream polishing step and a subsequent finish polishing step. In the upstream polishing step, as a polishing agent, a first alkaline aqueous solution containing abrasive grains with a density of 110.sup.14/cm.sup.3 or more is first supplied, and the supply is then switched to a supply of a second alkaline aqueous solution containing a water-soluble polymer and abrasive grains with a density of 510.sup.13/cm.sup.3 or less. In the finish polishing step, as a polishing agent, a third alkaline aqueous solution containing a water-soluble polymer and abrasive grains with a density of 510.sup.13/cm.sup.3 or less is supplied. Thus, the formation of not only PIDs but also scratches with small depth can be suppressed.

The present invention is method for polishing silicon wafer, the method including recovering used slurry containing polishing abrasive grains that have been supplied to the silicon wafer and used for polishing, and circulating and supplying the recovered used slurry to the silicon wafer to polish the silicon wafer, wherein mixed alkali solution containing chelating agent and either or both of a pH adjuster and a polishing rate accelerator is added to the recovered used slurry without adding unused polishing abrasive grains, and the recovered used slurry is circulated and supplied to the silicon wafer to polish the silicon wafer. As a result, there is provided a method for polishing a silicon wafer that can suppress the occurrence of metal impurity contamination and stabilize the composition (e.g., the concentration of the chelating agent) of the used slurry when the used slurry is circulated and supplied to the silicon wafer for polishing.

Disclosed is a polishing agent for synthetic quartz glass substrates, which is characterized by containing a colloidal solution of a colloidal silica or the like having a colloid concentration of 20-50% by mass, and a polycarboxylic acid polymer, an acidic amino acid, a phenol or a glycosaminoglycan.

A polishing agent for polishing a resin comprises abrasive grains, a water-soluble polymer having an ether bond, an organic solvent and water, wherein the abrasive grains have a positive charge in the polishing agent and an average particle diameter of the abrasive grains is larger than 20 nm.

To planarize a substrate having irregularities on its surface. Provided is a method of chemical mechanical polishing of a substrate. The method includes the step of polishing the substrate using a processing solution, and the step of changing concentration of an effective component in the processing solution, which contributes to the polishing of the substrate.

A flat-surface polishing method of performing a polishing operation for polishing a flat surface of a semiconductor substrate by using a polishing pad with circulation and supply of a polishing fluid including permanganate and water. The flat-surface polishing method includes: (a) during a predetermined time from start of the polishing operation, performing the polishing operation, while maintaining pH of the polishing fluid in a strong acid range by dropping a pH adjuster into the polishing fluid; and (b) after the predetermined time has elapsed and until the polishing operation is completed, performing the polishing operation, while making the pH of the polishing fluid higher than the strong acid range by stopping dropping the pH adjuster into the polishing fluid. Also disclosed is a flat-surface polishing apparatus used for carrying out the flat-surface polishing method.