Apparatus and method for washing polycrystalline silicon
AssigneeMitsubishi Materials Corporation
InventorsKazuhiro Sakai, Tetsuya Atsumi, Yukiyasu Miyata
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Abstract
Disclosed is a polycrystalline silicon washing apparatus that sequentially immerses polycrystalline silicon into a plurality of acid baths each of which is filled with an acid to wash the polycrystalline silicon. The temperatures of the acids in the acid baths are set such that the temperature of the acid in a later acid bath of adjacent acid baths is equal to or lower than that of a former acid bath and the temperature of the acid in the last acid bath is lower than that of the acid in the first acid bath. Each of the acid baths is provided with a temperature adjusting unit that controls the temperature of the acid at a constant value.
Claims6
A polycrystalline silicon washing apparatus comprising:
- a plurality of acid baths each of which is filled with an acid and into which polycrystalline silicon is sequentially immersed,
- wherein the temperatures of the acids in the acid baths are set such that the temperature of the acid in a later acid bath of adjacent acid baths is equal to or lower than that of a former acid bath, and
- the temperature of the acid in, the last acid bath is lower than that of the acid in the first acid bath.
A method for washing a polycrystalline silicon comprising:
- immersing the polycrystalline silicon into a high-temperature acid bath among the plurality of acid baths to remove impurities from the surface of the polycrystalline silicon;
- bringing out the polycrystalline silicon from the high-temperature acid bath;
- and
- immersing the polycrystalline silicon into the acid bath whose temperature is lower than that of the high-temperature acid bath to remove spots from the surface of the polycrystalline silicon.
Dependencies are inferred from the claim text.