Title:
CONTROLLING METHOD FOR OUTSIDE DIAMETER OF SINGLE CRYSTAL
Document Type and Number:
Japanese Patent JPH04108687
Kind Code:
A
Abstract:
PURPOSE:To enhance the precision for controlling the outside diameter of single crystal and to enhance the yield of a product by performing heating control for a heating means in accordance with the predictor of the outside diameter calculated by a specified method in the case of growing single crystal by a Czochralski process. CONSTITUTION:A heating means 15 is equipped to heat a crucible 14 holding the melt 12 for a raw material. Seed crystal 18 is brought into contact with the melt 12 in the crucible 14. Single crystal 19 is grown by pulling up this seed crystal 18 and also the weight of the grown single crystal 19 is measured 21 at every prescribed time. The outside diameter value of the grown single crystal 19 is calculated from the variation of this measured weight of single crystal. Heating temp. (detector 17) of the heating means 15 is controlled in accordance with the change with the lapse of time for the calculated outside diameter of single crystal. The following means is used in a method for controlling the outside diameter of single crystal 19. In other words, both a response function correspondent to the heating temp. of the heating means 15 and the target value of the outside diameter of single crystal 19 changed with time are previously set. The predictor of the outside diameter of single crystal after the elapse of prescribed time is calculated from both the calculated present outside diameter value of single crystal 19 and the response function. Deviation of both the predictor of this outside diameter and the target value of the outside diameter of single crystal after the elapse of prescribed time is calculated. The heating temp. of the heating means 15 is controlled 22, 23 according to this deviation.
Inventors:
SAKAMOTO TOSHIYUKI
Application Number:
JP22548990A
Publication Date:
April 09, 1992
Filing Date:
August 28, 1990
Export Citation:
Assignee:
FURUKAWA ELECTRIC CO LTD
International Classes:
C30B15/28; C30B27/02; (IPC1-7): C30B15/28
Attorney, Agent or Firm:
Koji Nagato