Ebara Corporation

Ritsuo Kikuta

Tetsuji Togawa

Kunihiko Sakurai

Tamami Takahashi

You Ishii

Norio Kimura

Masayoshi Hirose

Katsuaki Usui

Fujio Aoyama

Yoshihiro Niimura

Koji Kato

A polishing apparatus polishes a workpiece such as a semiconductor wafer to a flat mirror finish. The polishing apparatus includes a storage cassette for storing workpieces to be polished, at least two polishing units each having at least a turntable with a polishing cloth mounted thereon and a top ring for supporting a workpiece and pressing the workpiece against the polishing cloth, and a cleaning unit for cleaning a workpiece which has been polished by either one of the polishing units in such a state that the workpiece is removed from the top ring. The polishing apparatus further includes a transfer robot for transferring a workpiece between two of the storage cassette, the polishing units and the cleaning unit.

Polishing apparatus

A polishing cloth mounted on a turntable of a polishing apparatus and a polishing apparatus having such a polishing cloth for polishing a workpiece such as a semiconductor wafer to a flat mirror finish. The polishing cloth comprises a first elastic region contacting the surface of the workpiece and having a certain elastic modulus, and a second elastic region contacting the surface of the workpiece and having an elastic modulus different from the first elastic region. The second elastic region is surrounded by the first elastic region and has a smaller dimension in a radial direction of the turntable than a diameter of the workpiece when the second elastic region is held in contact with the workpiece. The position of the second elastic region is determined on the basis of an area in which the second elastic region acts on the workpiece.

Polishing cloth and polishing apparatus having such polishing cloth

A polishing apparatus is employed to polish an object to be polished by urging the surface of the object to be polished against the surface of a polishing cloth and causing a relative movement therebetween, while supplying a polishing liquid into an area between the object to be polished and the polishing cloth. A plurality of nozzles spray respective fluid jets to strike against the surface of the cloth. The plurality of nozzles include more than one type of nozzle which vary flow velocity, flow rate, angle of spray, and cross-sectional configuration of a jet. The plurality of nozzles have axes positioned at a location at different distances from the rotation axis of the polishing cloth.

An apparatus and method for polishing a workpiece such as a semiconductor wafer to a flat mirror finish. The workpiece is held by a top ring, and a surface of the workpiece is polished by pressing the workpiece against an abrasive cloth mounted on a turntable while applying an abrasive solution onto the abrasive cloth. While the workpiece is being polished, a surface of the abrasive cloth is dressed while applying a dressing liquid onto the abrasive cloth. A polishing operation and a dressing operation are performed in such a state that the abrasive solution and the dressing liquid do not interfere with each other.

Apparatus and method for polishing workpiece

A two-shaft rotary machine for use in a vacuum pump system includes rotors having a specific profile whereby any vibration and noise generated by the machine is minimized and its efficiency is increased. The number of lobes of each rotor is three or more. The tip and root portions of each rotor are defined by circular arcs, respectively, which are made smoothly continuous with each other through an involute curve. The ratio of the diameter of the tip circle to the diameter of the root circle is selected to fall within a range which is given by a specific expression.

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Ichikawa, Japan

Ritsuo Kikuta