Patent ID: 7179330
Filing Date: 2007-02-20
Classification: C30B,Y10T

Abstract:
1. A method of manufacturing a silicon single crystal by Czochralski method without performing Dash Necking method, comprising: providing a seed crystal having a tip end with a sharp-pointed shape or a truncation thereof in which an angle of the tip end is 28° or less; keeping the tip end of the seed crystal at just above a silicon melt to heat it before bringing the tip end of the seed crystal into contact with the silicon melt; subsequently, bringing the tip end of the seed crystal into contact with the silicon melt and immersing the seed crystal into the silicon melt to a desired diameter; and then shifting to pull the single crystal, wherein a temperature variation at a surface of the silicon melt is kept at ±5° C. or less at least for a period from a point of bringing the tip end of the seed crystal into contact with the silicon melt to a point of shifting to pull the single crystal, wherein the seed crystal is brought into contact with the silicon melt and immersed therein with setting a temperature of the silicon melt when bringing the tip end of the seed crystal into contact with the silicon melt to 10–20° C. higher compared to a temperature used for bringing the seed crystal into contact with the silicon melt in a method of manufacturing a silicon single crystal in Dash Necking method, and wherein the single crystal is pulled with setting a pulling rate to 0.5 mm/min. or less when forming a decreasing diameter portion for a period from a point immediately after stopping lowering of the seed crystal and shifting to pulling to a point of starting enlargement of a diameter of the crystal formed below the seed crystal.