Abstract: A wafer substrate is polished by disposing the wafer substrate between an abrasive cloth on a polishing platen and a plate, and relatively rotating the polishing platen and the plate for mirror polishing the surface of the wafer substrate with the abrasive cloth. A liquid is fed onto the plate side surface of the wafer substrate so that the wafer substrate is directly held to the plate by the adsorption force of the liquid, while performing the mirror polishing.

Abstract: A wafer substrate is polished by disposing the wafer substrate between an abrasive cloth on a polishing platen and a plate, and relatively rotating the polishing platen and the plate for mirror polishing the surface of the wafer substrate with the abrasive cloth. A liquid is fed onto the plate side surface of the wafer substrate so that the wafer substrate is directly held to the plate by the adsorption force of the liquid, while performing the mirror polishing.

Abstract: A piezoelectric oxide single crystal wafer, wherein number of particles adhering to a surface of the wafer and having a size of 1 &mgr;m or more is 85 or less per mm2. The piezoelectric oxide single crystal wafer consists of any one of lithium tantalate, lithium niobate, quartz crystal, lithium tetraborate and langasite, and suitably used for production of surface acoustic wave filters. The piezoelectric oxide single crystal wafer of the present invention enables fine electrode formation and device production with good yield.

Abstract: Apparatus for measuring the mechanical strength of a neck portion of a silicon seed crystal used for growing a silicon crystal by the Czochralski method includes a seed chuck for holding the seed crystal of a test sample and an end of a wire hung from an upper hook. A crystal holder which holds the other end part of the test sample from below is tied to a lower hook with another wire to support the holder. The apparatus includes means for pulling the hook at a given rate, and measuring means for continuously measuring tensile load. Such apparatus and the method thereby provide accurate measurement of mechanical strength of the neck portion of the silicon seed crystal with good precision and reproducibility. A single crystal ingot is grown under conditions affording good balance of productivity and safety.

Abstract: In a method of manufacturing a silicon monocrystal using the Czochralski method, a seed crystal is brought into contact with silicon melt and is then pulled such that after a neck portion is formed, a silicon monocrystal is grown below the neck portion. The crystal has a hollow portion which has an opening in a contact surface of the seed crystal to be brought into contact with the silicon melt. Alternatively, the seed crystal has a hollow portion which will have an opening in the contact surface of the seed crystal when the contact surface is brought into contact with the silicon melt. Use of such seed crystals makes it possible to increase the strength of the neck portion and to pull a heavy and long silicon monocrystal having a large diameter.

Abstract: The present invention provides a method of growing silicon single crystals by the Czochralski method, wherein the strength of a neck may be increased so as to delete the risk of severance thereof in a simple and easy way without the use of mechanically complex devices and thereby growing of a single crystal of a larger diameter and heavy weight is made practically possible.The method comprises the steps of: a single crystal being so grown from a seed crystal that the diameter of said single crystal gets gradually narrower until the length of a seed taper reaches 2.5 to 15 times the sectional size of the seed crystal; the diameter of a long near-cylindrical neck following the seed taper being so regulated that said diameter may be 0.09 to 0.9 times the sectional size of the seed crystal and 2.