Shin-etsu Handotai Co., Ltd.

Shin-etsu Handotai Kabushiki Kaisha

Masahiko Baba

Yoshihiro Hirano

Atsushi Ozaki

Nobuo Katsuoka

Kenji Araki

Hiroshi Ohtsuna

Atsushi Iwasaki

Susumu Sonokawa

Hiroyuki Ibe

Seiichiro Ohtsuka

Akiho Maeda

Hidetoshi Seki

A method for measuring a diameter of a single crystal ingot pulled up in a single crystal pulling apparatus comprising: calculating the weight of the pulled-up single crystal, calculating the descent amount of the melt surface relative to the crucible wall from the calculated pulled-up weight of the grown single crystal, and then either correcting the value of the ingot diameter actually measured by the optical sensor in response to the descent amount of the melt surface level or raising the crucible by an amount equal to the descent amount of the surface level.

Method for measuring the diameter of a single crystal ingot

The growing portion of a single crystal 1 grown by the pull method is recorded and the image signal is output to a digitizing circuit 3 that converts the image signal into binary data. A memory device 4 stores the digitized images and the point P at the boundary between dark and light is detected by scanning the stored digitized images starting from the scanning-start pixel and proceeding in the direction parallel to the direction of single crystal pulling. The diameter D of the growing portion of the single crystal is determined based upon the boundary P, and the scanning-start pixel for the current operation is set at the pixel that is separated from the boundary Pb in the preceding operation by a preset number of pixels d in the opposite direction of the scan.

Crystal diameter measuring device

Used in a Si crystal pulling apparatus using the Czochralski method, to lower the concentration of oxygen in the Si single crystal without increasing the production cost and to make the concentration substantially even all over the Si single crystal. The crystal 36 is produced by disposing a straightening tube 40 concentrically with and above a quartz crucible 22, letting inert gas flow down through the tube, dipping a seed crystal in Si molten liquid 28 in the quartz crucible and then pulling the seed crystal up. The concentration of oxygen in the Si single crystal is adjusted by controlling the distance H between the surface of the Si molten liquid and the bottom end of the straightening tube in accordance with the pull-up length Y or the pull-up time from a certain growth point of the crystal.

Method of adjusting concentration of oxygen in silicon single crystal

A device for measuring the diameter of the growing portions of the single crystals grown by the Czochralski technique is provided. This device is capable of measuring the crystal diameter with a high degree of accuracy over a wide range from the small-diameter portion thereof to the large diameter portion. A one-dimensional camera 28 and a two-dimensional camera 48 are fixed to a shoulder chamber 34 in such a manner that the optical axes thereof are parallel to each other. An optical path switch-over device, consisting of a cylinder 56, a movable plane mirror 52 mounted on a cylinder rod, and a fixed plane mirror 54, is provided. When the diameter of a neck portion of the single crystal 20 having a diameter of 10 mm or less is measured, the light reflected by the plane mirrors 52 and 54 is made incident on the two-dimensional camera 48, and the diameter of a bright ring 27 is measured on the basis of the image obtained by the two-dimensional camera. To measure the diameter of the conical and cylindrical portions 24 and 26 having a diameter of 10 mm or more, an image of a line lying across the bright ring 27 is obtained by the one-dimensional camera 28 by retracting the plane mirror 52, and the diameter of the bright ring 27 is measured.

A method for automatically controlling growing a single crystal neck portion by the CZ method, comprising the steps of pulling up a seed crystal (30) at 2 mm/min. for five minutes so as to grow a single crystal 32; next measuring a diameter of the lower end of the crystal; modifying an electric power for heating a melt based on the difference between the measured diameter and a reference value; waiting for five minutes; keeping the electric power constant for 10 minutes with controlling the pulling up speed so as to approach the diameter of the crystal to the reference value and with measuring the pulling up speed repeatedly; and next modifying the power based on the difference between the mean speed and a reference value. The last two steps are repeated alternatively.

Method of automatic control of growing neck portion of a single crystal

A method and an apparatus for measuring oscillation of a melt surface in growing a single crystal by Czochralski process, particularly in growing and pulling a crystal neck portion having a small diameter of 2 to 5 mm. The image of a region where the single crystal is being grown by the Czochralski process is taken by a camera 38 and the outside diameter D.sub.o of a bright ring image 70 of a brightness not lower than a predetermined reference value E is detected in accordance with video signals produced by the camera (Steps 80-83). The amount of oscillation of the outside diameter D.sub.o is measured as the amount S.sub.v of oscillation of the melt surface near the region where the single crystal is grown. The reference value E is determined by multiplying the maximum value of the video signals in one field with a predetermined constant K. The constant K is a value which, when the velocity of pulling of the single crystal is fixed to zero, substantially maximizes the amount of S.sub.v of oscillation of the outside diameter D.sub.o.

Method of and apparatus for measuring oscillation of the outside

Disclosed are a method of and a device for crystal diameter measurement in an apparatus for automatically controlling single crystal growth by the CZ technique. In the diameter measurement method, a growing region of a single crystal 32 is photographed by a camera 38, and an outer diamter Do of a luminous ring image 70 having a luminance above a reference value E is detected from a video signal supplied from the camera 38, the diameter Do thus detected being used for crystal diameter control. The crystal diameter measuring device comprises: a camera 38 for photographing a growing section of a single crystal 32 and supplying a video signal; devices for detecting a maximum video signal value with respect to one scanning line or more; a device for obtaining a reference value E corresponding to the above-mentioned maximum value; devices for binary-coding the video signal in comparison with the reference value E; and a device for detecting the outer diameter Do of a luminous image from a binary image obtained by the binary-coding.

Method of and device for diameter measurement used in automatically

A method for controlling a specific resistance of a single crystal in a Czochralski-method type single crystal pulling apparatus having a hermetical chamber in which the single crystal is pulled up from a polycrystal melt and an inert gas supply and exhaust system by means of which an inert gas is supplied to the hermetical chamber and exhausted therefrom; the method being characterized in that the pneumatic pressure in the hermetical chamber and the supply rate of the inert gas are controlled in accordance with a prepared control pattern with respect to the passage of pulling time.

Method for controlling specific resistance of single crystal and an

Used in an apparatus for pulling a Si single crystal 36 up from Si molten liquid 35 by using the Czochralski method. In order to produce a Si single crystal having a desired quality, the diameter of the Si single crystal is controlled by controlling the pull-up speed of the Si single crystal, the sum of a reference temperature set value T.sub.B (X), which is a function of a pull-up distance X of the Si single crystal from a certain growth point, and a value proportional to a diameter deviation .DELTA.D is regarded as a reference temperature, and electric power supplied to a heater (24) for heating the Si molten liquid is controlled so that the temperature of the vicinity of the heater is equal to the reference temperature. In order to easily and quickly set the temperature pattern, various operational data in producing a Si single crystal is automatically collected and stored in a magnetic memory disk (82) corresponding to quality data of the Si single crystals which have been produced, data similar to the quality of a Si single crystal to be produced is retrieved from the stored data, an operator selects the most similar data, the selected operational data is displayed in a display unit (80), and the operator sets the reference temperature pattern T.sub.B (X) on a screen of the display unit by using a mouse (78).

Method of forming a temperature pattern of heater and silicon single

An apparatus for measuring the diameter of a crystal in which an optical sensor scans along a sensing line which crosses at one point a luminous ring formed at the interface between a crystalline rod and a melt; the picture element position corresponding to a maximum luminance is discriminated when the optical sensor scans; the mean value of the picture element position is calculated over at least one revolution of the crystalline rod; and the diameter D of the crystalline rod at a portion thereof interfacing with the melt is calculated from the mean value and the level of the melt. Similarly, the minimum crystal diameter can be calculated by obtaining the picture element position corresponding to the minimum crystal diameter instead of obtaining the mean of the picture element position.

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Annaka, Japan

Masahiko Baba