Abstract: A polishing apparatus for polishing for example a semiconductor wafer to a high degree of flatness includes a turntable to the upper surface of which is affixed a polishing cloth and a top ring. A surface of the workpiece interposed between the polishing cloth on the turntable and the top ring is polished by pressing the workpiece against the polishing cloth with a predetermined pressure and moving the turntable and the top ring relative to each other. The turntable includes a set of annular small tables each of which is smaller than the diameter of the workpiece and determined on the basis of an area of effect on the workpiece.

Abstract: A polishing apparatus includes a turntable with an abrasive cloth mounted on an upper surface thereof, and a top ring disposed above the turntable for supporting a workpiece to be polished and pressing the workpiece against the abrasive cloth under a predetermined pressure. The turntable and the top ring are movable relatively to each other to polish a surface of the workpiece supported by the top ring with the abrasive cloth. The abrasive cloth has a projecting region on a surface thereof for more intensive contact with the workpiece than other surface regions of the abrasive cloth. The projecting region has a smaller dimension in a radial direction of the turntable than a diameter of the workpiece when the projecting region is held in contact with the workpiece. A position of the projecting region is determined on the basis of an area in which the projecting region acts on the workpiece.

Abstract: A polishing apparatus makes it possible to accurately detect the temperature of a workpiece during polishing and to perform polishing end point determination on the basis of this detected temperature. The polishing apparatus polishes irregularities in a surface of a workpiece such as for example a semiconductor wafer to a flat and mirror-like finish. A top ring holding a semiconductor wafer is provided with a temperature sensor. Frictional heat generated in the semiconductor wafer by polishing is detected by the temperature sensor, and a polishing end point is determined on the basis of the detected temperature.

Abstract: A polishing cloth is dressed between polishing processes each for polishing a workpiece such as a semiconductor wafer. The polishing cloth is dressed while supplying a dressing liquid such as water during a dressing process, and an abrasive liquid for polishing a workpiece is supplied to the polishing cloth for a predetermined period of time prior to a polishing process. The predetermined period of time may be present within the dressing process and immediately precedes the polishing process, and the dressing process may be carried out while supplying the abrasive liquid to the polishing cloth. Alternatively, the predetermined period of time may be present between the dressing process and the polishing process.

Abstract: A polishing apparatus polishes a workpiece such as a semiconductor wafer while detecting a thickness or a flatness of a surface layer of the workpiece on a real-time basis. The polishing apparatus includes a turntable with a polishing cloth mounted on an upper surface thereof, and a top ring disposed above the turntable for supporting a workpiece to be polished and such workpiece against the polishing cloth. The polishing apparatus also has a thickness detector for detecting the thickness of a surface layer of the workpiece supported by the top ring while the workpiece is being polished without exposing the workpiece. The thickness detector includes a sensor mounted in the turntable and including at least one light-emitting element for emitting light toward the surface layer of the workpiece and at least one light-detecting element for detecting light reflected from the surface layer of the workpiece.

Abstract: A vibrating column pump pumps liquid by making use of liquid vibration generated at the time when the vibrating pipe is vibrated in a longitudinal direction thereof. The vibrating column pump comprises a vibrating pipe for pumping liquid therethrough, flexible pipes for connecting both ends of the vibrating pipe with a stationary suction pipe and a stationary outlet pipe, vibrating means for vibrating the vibrating pipe in a longitudinal direction thereof, and retainer means for removably retaining the vibrating pipe in such a manner that the vibrating pipe is removably connected to the vibrating means. The liquid contacting unit including the vibrating pipe and the flexible pipes is separated from the vibrating means so that the liquid contacting unit is disposable and can be easily replaced with a new one.

Abstract: An active magnetic bearing apparatus wherein an object designed to be suspended is supported by a plurality of active magnetic bearings and is suspended in a non-contact state so that the object is caused to move in either a rotational or reciprocating manner in such a state. The magnetic force of the respective active magnetic bearings is controlled electrically. A delay control mechanism is provided to cause a delay in the starting-up time for the respective active magnetic bearings so that these bearings are caused to start up sequentially when they are activated, thus making it possible to make the capacity of the power source as small as possible.

Abstract: A rotation control system for preventing unbalance vibrations and synchronous disturbance vibrations of a rotary member suspended by a magnetic bearing. This system includes a vibration detector which detects radial vibration of the rotary member. On the basis of the detected radial vibration, a compensating signal which has the same amplitude and cycle as the vibration component having the rotational frequency is generated. The difference between the detected vibration and the compensating signal is obtained and used for controlling the radial position of the magnetic bearing.

Abstract: An active type magnetic bearing system includes magnetic bearings for suspending a rotary body to permit it to rotate about its rotational axis. A control system supplies the magnetic bearings with signals to control the radial position of the rotary body, and comprises displacement detecting circuits for detecting any displacement of the radial position of the rotary body and a control circuit for producing a control signal which serves to suppress any unstable vibration of the rotary body.

Abstract: A mechanical seal is disclosed wherein an intermediate floating ring is employed between a seat sleeve and a rotary ring. Each of the rotary ring, intermediate floating ring and the seat sleeve are pressed against each other so as to be relatively rotatable at their respective abutting interfaces, each of the rotary ring, intermediate ring and the seat sleeve being separated from each other with proper clearances between the opposing surfaces thereof at places which are outward of the sliding interfaces and each of the opposing surfaces is provided with an annular groove and a cascade of blades therein so that a fluid coupling is formed between the adjacent opposing surfaces.