Title:
METHOD FOR PULLING UP SINGLE CRYSTAL
Document Type and Number:
Japanese Patent JP3348458
Kind Code:
B2
Abstract:
PURPOSE: To suppress the variation in quality and improve the quality of a single crystal by pulling up a single crystal in such a manner as to keep the deformation ratio of the single crystal at a prescribed level during pull-up operation.
CONSTITUTION: The optimum pull-up speed and the target deformation ratio are set according to the diameter of the single crystal 5, etc., before starting the pull-up operation. The deformation ratio is defined by (maximum diameter-minimum diameter)/(average diameter)×100 and is maintained to 0.3-1.5%. Simultaneously with the start of pull-up operation, the diameter of a fusion ring formed at the boundary between the molten raw material liquid 3 and the single crystal 5 is measured by an optical measuring means 6 and the average diameter and the deformation ratio of the single crystal 5 is calculated from the measured value. The deviation of the measured deformation ratio from the target deformation ratio is calculated, a correction value for the pull-up speed is calculated therefrom and the value is added to the preset pull-up speed to obtain a target pull-up speed. The correction value of the molten liquid temperature is determined based on the deviation of the measured deformation ratio from the target deformation ratio and the power of a heater 2 is controlled according to the result. Further, the correction value of the pull-up speed is calculated based on the deviation of the measured average diameter from the target diameter and the result is added to the target pull-up speed and outputted to a pull-up machine 4.
Inventors:
Soichiro Kondo
Kaoru Kuramochi
Masaru Taniguchi
Kaoru Kuramochi
Masaru Taniguchi
Application Number:
JP7919593A
Publication Date:
November 20, 2002
Filing Date:
March 11, 1993
Export Citation:
Assignee:
Mitsubishi Sumitomo Silicon Co., Ltd.
International Classes:
C30B15/22; C30B29/06; H01L21/208; (IPC1-7): C30B15/22; C30B29/06; H01L21/208
Domestic Patent References:
| JP196088A | ||||
| JP6033299A | ||||
| JP6283395A | ||||
| JP57156397A | ||||
| JP196089A | ||||
| JP6469590A |
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