A polishing composition that can suppress surface defects and reduce haze is provided. A polishing composition includes: abrasives; at least one water-soluble polymer selected from vinyl alcohol-based resins having a 1,2-diol structural unit; and an alkali compound, where an average particle size of particles in the polishing composition measured by dynamic light scattering is not more than 55 nm. Preferably, the polishing composition further includes a non-ionic surfactant. Preferably, the polishing composition further includes a polyalcohol.

A polishing method capable of removing waviness on a resin-coated surface having a curved surface is provided. The resin-coated surface having the curved surface is polished by using a polishing pad having a polishing surface formed of a hard resin layer.

A polishing method capable of removing waviness on a resin-coated surface having a curved surface is provided. The resin-coated surface having the curved surface is polished by using a polishing pad having a polishing surface formed of a hard resin layer.

The present invention provides a method for producing a polishing composition which can polish an object to be polished at a high polishing speed and with fewer scratches (defects).

The present invention is a method for producing a polishing composition, the method including: preparing silica in which an intensity of a peak of a silica four-membered ring structure and an intensity of a peak derived from a silica random network structure when analyzed by Raman spectroscopy satisfy a predetermined requirement; and mixing the silica with a dispersing medium.

The present invention provides a polishing composition which polishes an object to be polished at a high polishing speed and with less scratches (defects).

The present invention is a polishing composition including silica having a maximum peak temperature of 30 C. or higher and 53 C. or lower in a weight change rate distribution curve obtained by thermogravimetric measurement in a range of 25 C. or higher and 250 C. or lower, and having a pH at 25 C. of less than 6.0.

A method of producing a wafer includes forming a peel-off layer in a hexagonal single-crystal ingot by applying a laser beam having a wavelength transmittable through the ingot while positioning a focal point of the laser beam in the ingot at a depth corresponding to the thickness of a wafer to be produced from an end face of the ingot, generating ultrasonic waves from an ultrasonic wave generating unit positioned in facing relation to the wafer to be produced across a water layer interposed therebetween, thereby to break the peel-off layer, and detecting when the wafer to be produced is peeled off the ingot based on a change that is detected in the height of an upper surface of the wafer to be produced by a height detecting unit positioned above the upper surface of the wafer to be produced across the water wafer interposed therebetween.

A method of producing a wafer includes forming a peel-off layer in a hexagonal single-crystal ingot by applying a laser beam having a wavelength transmittable through the ingot while positioning a focal point of the laser beam in the ingot at a depth corresponding to the thickness of a wafer to be produced from an end face of the ingot, generating ultrasonic waves from an ultrasonic wave generating unit positioned in facing relation to the wafer to be produced across a water layer interposed therebetween, thereby to break the peel-off layer, and detecting when the wafer to be produced is peeled off the ingot based on a change that is detected in the height of an upper surface of the wafer to be produced by a height detecting unit positioned above the upper surface of the wafer to be produced across the water wafer interposed therebetween.

Provided is a fumed silica for chemical-mechanical polishing with which post-polishing scratches occurring on a surface of an object to be polished can be significantly reduced, and which is important for miniaturization and multi-layering of a structure. The fumed silica according to the present invention has a BET specific surface area of 57-400 m.sup.2/g. In a liquid dispersion which is obtained by ultrasonically dispersing 6.25 mass % of this fumed silica in water at a vibration frequency of 20 kHz and an amplitude of 15-25 m for 3 minutes, the amount of residues on a sieve is 5 ppm or less as measured by wet sieving using an electroformed sieve having a mesh opening size of 5 m.

The present invention provides a liquid supplying device that can determine whether a CLC can be used appropriately. A liquid supplying device for supplying a liquid from a liquid source to a cleaning device is provided. The liquid supplying device includes a flow rate control device that measures a flow rate of a liquid from the liquid source and controls the flow rate based on the measured value, an IN-side pressure gauge provided between the liquid source and the flow rate control device and an OUT-side pressure gauge provided between the flow rate control device and the cleaning device.

The present invention provides a liquid supplying device that can determine whether a CLC can be used appropriately. A liquid supplying device for supplying a liquid from a liquid source to a cleaning device is provided. The liquid supplying device includes a flow rate control device that measures a flow rate of a liquid from the liquid source and controls the flow rate based on the measured value, an IN-side pressure gauge provided between the liquid source and the flow rate control device and an OUT-side pressure gauge provided between the flow rate control device and the cleaning device.