Flow guide cylinder for monocrystal silicon growth furnace and application thereof

Abstract

The invention provides a flow guide cylinder for a monocrystal silicon growth furnace, which includes a tapered flow guide inner cylinder and a tapered flow guide outer cylinder, a heat preservation layer filled with heat preservation carbon felt is disposed therebetween. A heat insulation layer made from metal molybdenum or tungsten is disposed between the outer cylinder and the heat preservation layer. The tapered inner cylinder is used for absorbing radiation heat from a crystal ingot and then cooling the crystal ingot by means of gas rectifying to increase axial temperature gradient of the crystal ingot. Meanwhile, by means of the flow guide cylinder to rectify the gas, the flow speed of the gas is increased to reduce the partial pressure of SiO at liquid level of the melt, thereby reducing oxygen content in the melt. The flow guide cylinder can improve the quality of the crystal ingot, can accelerate growth of the crystal and can reduce production cost. The invention also provides an application method of eliminating polycrystal particles in quartz crucible walls by means of the flow guide cylinder.

Description

technical field [0001] The invention belongs to a single crystal silicon manufacturing device, in particular to a flow guiding cylinder for a single crystal silicon growth furnace which increases the growth rate of silicon single crystal and reduces the oxygen content in the single crystal silicon. Background technique [0002] With the rapid development of integrated circuits toward miniaturization, low power consumption, high computing speed, and narrow line width, higher requirements are put forward for the quality and performance of silicon chips used for large-scale integrated circuits. As the size of the crystal ingot increases, the difficulty in designing the temperature field required for crystal ingot growth increases, and the difficulty and cost of manufacturing a single crystal silicon growth furnace increase significantly. [0003] In the manufacturing process of integrated circuits, there are strict requirements on the oxygen content in silicon wafers, so as to ...

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Problems solved by technology

[0004] In the prior art, such as CN201420688047.7, a new type of guide tube for improving the growth rate of Czochralski silicon single crystal, although the idea of ​​independent design of the inner and outer tubes and the inner tube is adopted, which reduces the impact of the guide tube on the However, at the end of the growth of the ingot, as the volume of the melt decreases, the exposed area of ​​the quartz crucible increases significantly, and the radiant heat from the wall of the quartz crucible to the outer cylinder increases significantly, resulting in an increase in the temperature of the inner cylinder. The ingot produces large radiant heat, which is not conducive to the growth of the ingot

[0005] Also such as a kind of guide tube for drawing large-diameter N-type single crystal described in 201320808094.6, although a molybdenum partition is set between the inner tank and the insulation layer, the molybdenum partition is not directly arranged between the outer tank and the insulation layer, resulting in The heat radiation from the liquid surface of the melt and the wall of the quartz crucible passes through the outer cylinder and is absorbed by the insulation layer. At the same time, the insulation layer is in close contact with the molybdenum partition to form conduction and heat conduction, so that the temperature of the molybdenum partition rises and is higher than the temperature of the inner tank. Form heat radiation to the inner cylinder, which is not conducive to the heat release of the crystal ingot

[0006] To sum up, the existing technology can increase the growth rate of the crystal ingot and reduce the oxygen concentration in the melt to a certain extent, but there are still many problems, such as: (1) At the end of the growth of the crystal ingot, the crucible wall guides the flow The radiation of the tube is intensified, the temperature of the guide tube rises, and the radiation of the guide tube itself to the crystal ingot is intensified, which is not conducive to the growth of the crystal ingot

(2) The crucible and melt heat radiation heat loss is serious, the time for heating up the material is long, and the power consumption of the single crystal furnace is high

[0007] At the same time, during the growth process of monocrystalline silicon, after the polycrystalline silicon raw material is melted, many unmelted polycrystalline silicon particles or blocks are easy to adhere to the inner wall of the quartz crucible. Usually, by increasing the output power of the graphite heater, the temperature of the crucible wall is increased. Slowly melt particles or blocks, which takes a long time, consumes a lot of energy, and has limited removal capacity

Moreover, during the pulling and growing process of the crystal ingot, particles or blocks adhering to the inner wall of the quartz crucible tend to fall off suddenly and fall into the crucible, which seriously damages the stability of the melt temperature field and fluid field and affects the quality of the crystal ingot.

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