Apparatus and method for pulling up single crystals

摘要

A crystal-clamping fixture 30 is suspended by a pulling up mechanism 1 through the use of wires. The crystal-clamping fixture 30 includes a box 31 and a plurality of holding rods 32. The box 31 has two openings formed on its top and bottom sides. The reduced portion 2a, the enlarged portion 2b and the necked portion 2c formed beneath the seed crystal 5 are allowed to penetrate through the two openings during the pulling up operation. A plurality of "S" shaped slots 31a, 31b are formed on the lateral sides of the box 31. The holding rods 32 capable of rotating along the path of the "S" shaped slots 31a, 31b are horizontally disposed within the box 31 by inserting their two end portions through the "S" shaped slots 31a, 31b. The holding rods kept restrained at the upper ends of the "S" shaped slots are pushed out by the conic surface formed at the upper part of the enlarged portion 2b and rotate and descend to reach the lower ends of the "S" shaped slots. At the time the crystal-clamping fixture 30 is directed to ascend a small distance, then the holding rods 32 contact the conic surface formed between the enlarged portion 2b and the necked portion 2c to clamp the single crystal 2.