Abstract: The present invention is a wafer polishing apparatus with a device that detects the polishing end according to a change in rotation resistance of a wafer during polishing. The wafer polishing apparatus comprises a head body and a carrier which are connected with each other by a connecting bar which is provided with a strain gage, and determines strain in a horizontal direction of the connecting bar by the strain gage so as to determine a rotation torque of the carrier, whereby accurately detects the polishing end. Since a retainer ring is mounted to the outer periphery of the carrier via an O ring, the impact at contacting of the wafer with the retainer ring can be absorbed by the O ring, thus the wafer is prevented from damage. Because the retainer ring is mounted to the carrier without a gap, the outer periphery of the wafer is enclosed by the retainer ring, and the wafer can be polished in a state where its center is held on the central axis of the carrier.

Abstract: An apparatus for polishing wafers wherein a retainer ring 40 is held by a carrier 32 of a wafer-holding head 20 by using an O-ring 31. Further, a protection sheet 80 for a wafer 2 is held by the retainer ring so as to cover the surface of an air-blow member 34 of the carrier. While the wafer is being held and polished, therefore, the back surface of the wafer does not come into direct contact with the carrier, and the protection sheet is interposed between the back surface of the wafer and the carrier.

Abstract: The present invention is a wafer polishing apparatus with a device that detects the polishing end according to a change in rotation resistance of a wafer during polishing. The wafer polishing apparatus comprises a head body and a carrier which are connected with each other by a connecting bar which is provided with a strain gage, and determines strain in a horizontal direction of the connecting bar by the strain gage so as to determine a rotation torque of the carrier, whereby accurately detects the polishing end. Since a retainer ring is mounted to the outer periphery of the carrier via an O ring, the impact at contacting of the wafer with the retainer ring can be absorbed by the O ring, thus the wafer is prevented from damage. Because the retainer ring is mounted to the carrier without a gap, the outer periphery of the wafer is enclosed by the retainer ring, and the wafer can be polished in a state where its center is held on the central axis of the carrier.

Abstract: A polishing head of a polishing apparatus of this invention has a structure in which an air blast port is formed in a lower surface of a carrier 20, and an upper outer peripheral portion 24 of the carrier is so formed as to protrude in a diametric direction, and is placed on a retainer ring 30 to thereby form a seal portion 25. The retainer ring clamps a peripheral edge of a rubber sheet in such a form as to cover the carrier. Consequently, an air chamber 61 is formed between the carrier lower surface and the rubber sheet, and an air pressure of this air chamber pushes a wafer W to a polishing cloth 2.

Abstract: The polishing apparatus comprises a turn table, which polishes a semiconductor wafer, and a holding and pressing part, which holds and presses the semiconductor wafer against a polishing surface of the turn table. The holding and pressing part transmits a force from an air bag to the semiconductor wafer via a pressurized fluid layer to thereby press the semiconductor wafer against the polishing surface via the pressurized fluid layer, so that the semiconductor wafer can be polished. Thereby, it is possible to uniformly polish the semiconductor wafer.

Abstract: The first air guide groove is formed at the bottom of a carrier along the inner circumference of a circle whose radius corresponds to the maximum radius of a wafer. The air is supplied to the outer periphery of the wafer through the first air guide groove to form a pressure air layer between the carrier and the wafer. The formation of the pressure air layer makes the air pressure applied to the wafer uniform on the entire surface of the wafer, and thus, the wafer can be polished under a uniform pressure force. The second air guide groove is formed along the inner circumference of a circle whose radius corresponds to the minimum radius of the wafer, and therefore, the wafer with an orientation flat or notch can be polished under a uniform pressure force.

Abstract: Sensors detect a stock removal of a wafer during polishing, and a CPU calculates the stock removal in accordance with information from the sensors. The CPU compares the actual stock removal detected by the sensors and a model stock removal stored in RAM, and determines timings for dressing and replacing said polishing pad in accordance with a difference between the actual stock removal and the model stock removal. The determination results are shown on a display.

Abstract: A wafer is polished while it is pressed against a polishing cloth through a pressure air layer, and a polished surface adjustment ring as well as the wafer are pressed against the polishing cloth. The wafer is polished in the state wherein a collapsing position of the polished surface adjustment ring with respect to the polishing cloth is set in such a way that the polishing pressure which is applied from the polishing cloth to the wafer can be constant.

Abstract: The differential transformer is secured to the wafer holding table provided in the head, and the core of the differential transformer is secured to the rod member, which is provided to the head and freely projects and retracts from the face of the wafer. Then, the tip of the rod member is in contact with the polishing pad and keeps the core at a constant height from the polishing pad during polishing. When the head is displaced as polishing progresses with respect to the polishing pad, the differential transformer is displaced in connection with the displacement of the head. Therefore, the removed amount of the wafer can be determined by measuring the displacement amount of the differential transformer with respect to the core.

Abstract: A semiconductor wafer is held by a wafer mount plate, which is loosely inserted into a housing. An air chamber is formed between the wafer mount plate and the housing. A retainer ring encloses the semiconductor wafer, and the semiconductor wafer as well as the retainer ring contacts with a polishing pad. An roughness is formed at the bottom of the retainer ring so as to dress the polishing pad. Polishing liquid is supplied to the inside of the retainer ring. Thus, the polishing pressure can be uniformly applied and the polishing liquid can be uniformly supplied on the whole surface of the semiconductor wafer, and the polishing for the semiconductor wafer and the dressing for the polishing pad can be performed at the same time.

Abstract: A surface texture measuring instrument comprises an immovable casing located on an object, a movable pick-up for detecting a surface roughness of the object, and a driving unit in the casing for driving the pick-up. The pick-up comprises a skid having a curved surface for absorbing a waviness component of the surface of the object, and a stylus in the skid for detecting the surface roughness thereof. The stylus is slightly deviated from a center of the curved surface to give a more accurate measurement of the surface roughness.

Abstract: A ground moisture testing and indicating device designed for quick and simple measurement of ground moisture by an untrained layman for use in connection with sowing seeds, transplanting saplings and young plants, and cultivating plants of all kinds by ascertaining the ground moisture at predetermined depths. The device is particularly useful in irrigated gardening and horticultural and agricultural farming. As conductivity of electrical current in soil varies with the content of moisture therein, the resistance of the soil is a direct function of the moisture content of the soil. The present device measures resistance of the soil at a given depth and thereby indicates the moisture of the soil at that point. A direct current voltage is generated to indicate such value by a suitable indicating device, such as a meter, a sound device utilizing a loudspeaker, or an earphone, or a visual device, such as a lamp or photodiode, etc., for detection and evaluation.