A method for growing polysilicon target material

Abstract

The invention relates to a method for growing a polycrystalline silicon target material. The method comprises the following processes of charging a furnace, melting a material, seeding, shouldering, rotating shoulder, obtaining equal diameter and ending, wherein the seeding process comprises the following steps: after a polycrystalline silicon raw material is melt, reducing heating power to the size required by seeding, and reducing the temperature until the liquid level of molten silicon has supercooling degree; reducing a seed crystal rod on a lifting device, and enabling the bottom surface of a seed crystal to make contact with the molten silicon; when a diaphragm at a contact position between the seed crystal and the molten silicon is detected to be stable, upward lifting the seed crystal at the crystal lifting speed of 3 to 7mm / min, and solidifying a crystal when a contact surface between the seed crystal and the molten silicon grows along with the lifting of the seed crystal; when the size of the obtained crystal is kept at 3 to 5mm, and the length is 160 to 190mm, obtaining a fine crystal, further reducing the crystal lifting speed and turning into a shouldering stage; the shouldering process comprises the following steps: reducing the crystal lifting speed to be 0.4 to 0.8mm / min; meanwhile, carrying out linear temperature reduction at the temperature reduction speed of 15 to 25DEG C / hr, shouldering the crystal, and stopping linear temperature reduction until the diameter of the crystal is smaller than the diameter of 5 to 7mm required by the product.

Description

technical field [0001] The invention relates to the technical field of polysilicon targets, in particular to a method for growing polysilicon targets. Background technique [0002] The target is the basic consumable in the process of preparing functional thin films by magnetron sputtering. The quality of the target material plays a crucial role in the performance of the thin film. Silicon target is a simple sputtering target source, which is mainly used for magnetron sputtering to prepare thin films such as silicon and silicon dioxide. It has important applications in information storage, low-e glass, LCD flat panel display, solar cells and other fields. [0003] Silicon target products are divided into single crystal silicon target and polycrystalline silicon target. Compared with single crystal silicon target, polycrystalline silicon target is easy to stimulate, has lower cost and large output. Further improving the quality of polysilicon targets is the main goal at this...

AI Technical Summary

Problems solved by technology

[0006] Second, the crystal grains are large and uneven

The first is that the solid-liquid interface protrudes too much during the solidification process (it can be approximately reflected from the shape of the top of the finished crystal), the environment of each part (such as temperature, pressure, etc.) is quite different, and the product size is too large, which affects each part of the crystal. The production rate lacks control means, and the effect of process control is not timely or obvious

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