Sumco Corporation

Sumitomo Mitsubishi Silicon Corporation

Mitsubishi Materials Silicon Corporation

Senlin Fu

Yoji Suzuki

Kazuhiro Harada

Hisashi Furuya

Naoki Ono

Norihito Fukatsu

Hidenobu Abe

The axial temperature gradient G at the vicinity of the solid-liquid interfacein an ingot is calculated in consideration of the heating value of a heater, the dimensions and physical property values of furnace inside components and the convection of the meltbefore pulling up the single crystal ingotby a pullerby use of a numerical simulation of synthetic heater transfers and a numerical simulation of melt convection. Then, the pulling velocity V of the single crystal ingot is determined from an value experienced of the ratio C=V/G of the pulling velocity V and the axial temperature gradient G of the single crystal ingot at which the single crystal ingot becomes defect-free, obtained when the single crystal ingot was pulled up by a same type puller as the puller in the past, and the axial temperature gradient G calculated by use of the simulations. Then, the ingot is pulled up at the pulling velocity, and the change value of the temperature gradient G to the deterioration value of partial furnace inside components roughly measured while the ingot is pulled up is roughly forecasted by use of the simulations. And further, the pulling velocity V of the ingot is adjusted in such a way that the ratio C should become the value experienced according to the change value of the temperature gradient G roughly forecasted.

Method for pulling up single crystal

A heat shielding member is provided in a device pulling up a silicon single crystal rod from a silicon melt stored in a quartz crucible, and equipped with a tube portion which shields radiant heat from the heater surrounding the outer peripheral face of the silicon single crystal rod, a swelling portion provided at the lower portion of the tube portion, and a ring-shape heat accumulating portion provided at the inside of the swelling portion. The heat accumulating portion is a thermal conductivity of 5 W/(m&#xb7;&#xb0; C.) or less, its inner peripheral face is a height (H) of 10 mm or more and d/2 or less when the diameter of the silicon single crystal rod is referred to as d and the minimum distance (W) between the outer peripheral face of the silicon single crystal rod and the inner peripheral face of the heat accumulating portion is formed so as to be 10 mm or more and 0.2 d or less, a vertical distance (H) between the upper rim of the outer peripheral face and the lowest portion of the heat accumulating portion is 10 mm or more and d or less, and the minimum distance (W) between the inner peripheral face of the quartz crucible and the outer peripheral face of the heat accumulating portion is 20 mm or more and d/4 or less.

Heat shielding member of silicon single crystal pulling system

[Problem] A silicon single crystal ingot in which point defect agglomerates do not exist over a substantially entire length thereof is manufactured without reducing a pure margin. [Solving Means] A heat shielding membercomprises a bulge portionwhich is provided to bulge in an in-cylinder direction at a lower portion of a cylindrical portionand has a heat storage memberprovided therein. A flow quantity of an inert gas flowing down between the bulge portionin the heat shielding memberand an ingotwhen pulling up a top-side ingotof the silicon single crystal ingotis set larger than a flow quantity of the inert gas flowing down between the bulge portionand the ingotwhen pulling up a bottom-side ingotof the silicon single crystal ingot, thereby pulling up the ingot. Alternatively, an intensity of a cusp magnetic fieldwhen pulling up the top-side ingotis set higher than an intensity of the cusp magnetic fieldwhen pulling up the bottom-side ingot

Silicon single crystal pulling method

A thermal shield device is equipped in a crystal-pulling apparatus for pulling a silicon monocrystal ingot from a silicon melt reserved in a quartz crucible having an outer peripheral surface encircled with a heater. The thermal shield device has a tubular part to be used for surrounding a silicon monocrystal ingot being pulled and grown in an upward direction to prevent radiant heat from the heater toward the silicon monocrystal ingot. The tubular part has a lower end positioned above a surface of the silicon melt with a predetermined spacing therebetween. A protruding part is formed on a lower portion of the tubular part and filled with a thermal-insulating member. The protruding part extends to the inside of the tubular part and has a bottom wall, a vertical wall, and a top wall. The bottom wall is shaped like a ring having an outer edge connected to a lower edge of the tubular part and extends to the proximity of an outer peripheral surface of the silicon monocrystal ingot. The vertical wall is positioned at a predetermined distance from the outer peripheral surface of the silicon monocrystal ingot and connected to an inner edge of the bottom wall. The top wall has a lower edge connected to an upper edge of the vertical wall and an upper edge attached to an inner peripheral surface of the tubular part and extends in an upward direction with a gradual increase in diameter.

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Tokyo, Japan

Senlin Fu