Manufacturing method of high-quality quartz crucible

Abstract

The invention relates to a manufacturing method of a high-quality quartz crucible, a vacuum arc method is adopted for melting, and the displacement of a graphite electrode and the retention time on each position meet the following conditions: the end face position of an upper opening of a mold is taken as a zero point, the end of the graphite electrode above the zero point is +, and the end of the graphite electrode below the zero point is-; the initial position of the graphite electrode is + 0.10-0.30 times of the outer diameter of the crucible, the retention time is greater than or equal to 2 minutes, then the graphite electrode is sequentially descended according to a step displacement method, the graphite electrode is retained for a period of time every time when the graphite electrode is descended, and the graphite electrode reaches the bottom polishing position after displacement is carried out for at least 3 times; the bottom polishing position is the lowest position where the graphite electrode reaches, enters the crucible blank and is 300-550mm away from the bottom of the crucible; at the position, the graphite electrode stays and performs high-temperature polishing and volatilization impurity removal on the bottom of the crucible; the outer diameter of the crucible is + 0.05-0.07 times of the outer diameter of the crucible, and high-temperature volatilization impurity removal is carried out on the upper portion of the inner wall of the quartz crucible at the tail sweeping station. The method is used for improving the purity of the transparent layer of the crucible, enhancing the high-temperature deformation resistance and the like.

Description

Technical field [0001] The present invention relates to the field of monocrystalline silicon production technology, in particular, a method of making quartz crucibles used when manufacturing silicon monocrystallines by Czochralski method (hereinafter referred to as CZ straight-pull method). Background [0002] Silicon single crystal is one of the most important raw materials for making silicon-based semiconductor materials and solar cells. Silicon single crystals are mainly produced by CZ direct drawing. In the CZ straight-pull method, the polycrystalline silicon raw material is placed in the quartz crucible to heat the molten silicon melt, and the tie rod drives the seed crystal down so that it contacts the silicon melt, and then slowly lifts the seed crystal upward to form a silicon single crystal rod. Quartz crucibles are generally double-layered structures, with a transparent layer without bubbles on the inner wall and a non-transparent layer with more bubble content on the ...

AI Technical Summary

Problems solved by technology

The position of the graphite electrode in the FT method is fixed, and only regular drop compensation is made for the consumption of the graphite electrode (drop a certain distance to compensate for the loss of the electrode). At the same time, the existing preparation method only improves the production quality of the quartz crucible by adjusting the current.

However, in actual production, it is found that the improvement of the quality of the quartz crucible is very limited only by adjusting the current size, and once the production equipment is built, the current size that the hardware can carry is limited, so it is difficult to improve the production quality of the crucible by replacing the high current. , and the cost of changing the hardware and rebuilding the equipment is also very high

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