CN-121992499-A - Single crystal pulling apparatus

CN121992499ACN 121992499 ACN121992499 ACN 121992499ACN-121992499-A

Abstract

Provided is a single crystal pulling apparatus which is excellent in cooling performance of a single crystal and can observe a liquid surface. A Czochralski method-based single crystal pulling apparatus includes a cylindrical first cooling body for cooling a growing single crystal pulled from a melt in a crucible around an outer peripheral surface of the growing single crystal, an inverted conical second cooling body disposed below the first cooling body and cooling the growing single crystal around the outer peripheral surface of the growing single crystal, and an imaging device for observing a liquid surface of the melt, wherein an inner diameter of an upper end of the second cooling body is larger than an outer diameter of a lower end of the first cooling body to form a linear optical path extending from the liquid surface through a gap between the lower end of the second cooling body and the outer peripheral surface of the growing single crystal and a gap between the upper end of the second cooling body and the lower end of the first cooling body to the imaging device.

Inventors

Daihara Chongyi
Red poppy

Assignees

胜高股份有限公司

Dates

Publication Date: 20260508
Application Date: 20251104
Priority Date: 20241106

Claims (3)

1. A single crystal pulling apparatus based on the Czochralski method, The device comprises: a cylindrical first cooling body that cools a growing single crystal pulled from a melt in a crucible around an outer peripheral surface of the single crystal; a second cooling body having an inverted conical tubular shape, disposed below the first cooling body, for cooling the single crystal being grown around the outer peripheral surface of the single crystal; A photographing device for observing the liquid level of the molten metal, The inner diameter of the upper end of the second cooling body is larger than the outer diameter of the lower end of the first cooling body, A linear optical path is formed from the liquid surface to the imaging device through a gap between a lower end of the second cooling body and the outer peripheral surface of the growing single crystal, and through a gap between the upper end of the second cooling body and the lower end of the first cooling body.
2. A single crystal pulling apparatus according to claim 1, wherein, When the inner diameter of the upper end of the second cooling body is A and the inner diameter of the lower end of the second cooling body is B, A/B is 1.1-1.5.
3. A single crystal pulling apparatus according to claim 1 or 2, wherein, The distance between the lower end of the second cooling body and the outer peripheral surface of the growing single crystal is 20-70 mm.

Description

Single crystal pulling apparatus Technical Field The present invention relates to a single crystal pulling apparatus. Background A single crystal pulling apparatus according to the czochralski method is known, which includes a cylindrical cooling body that cools a single crystal being grown, which is pulled up from a melt in a crucible, around an outer peripheral surface of the single crystal, and an imaging device that observes a level of the melt in the crucible (see, for example, patent document 1). Patent document 1, japanese patent laid-open publication No. 2003-165790. In patent document 1, the single crystal being grown is cooled by surrounding the outer peripheral surface of the single crystal being grown with a cooling body, whereby the single crystal being grown can be efficiently cooled to increase the pulling rate, and the boundary region between the single crystal and the liquid surface can be observed with an imaging device through a notch portion provided at the lower end portion of the cooling body. However, if the notch is provided at the lower end portion of the cooling body, there is a problem in that uniformity of heat distribution in the circumferential direction of the notch is deteriorated. Disclosure of Invention The invention aims to provide a single crystal pulling device which has excellent cooling performance and can observe the liquid level. One aspect of the present invention is as follows. [1] A single crystal pulling apparatus based on the Czochralski method, The device comprises: A cylindrical first cooling body that surrounds an outer peripheral surface of a growing single crystal pulled from a melt in a crucible and cools the single crystal; A second cooling body having an inverted conical tubular shape, disposed below the first cooling body, and surrounding the outer peripheral surface of the growing single crystal to cool the single crystal; A photographing device for observing the liquid level of the molten metal, The inner diameter of the upper end of the second cooling body is larger than the outer diameter of the lower end of the first cooling body, A linear optical path is formed from the liquid surface to the imaging device through a gap between a lower end of the second cooling body and the outer peripheral surface of the growing single crystal, and a gap between the upper end of the second cooling body and the lower end of the first cooling body. [2] The single crystal pulling apparatus according to [1], When the inner diameter of the upper end of the second cooling body is A and the inner diameter of the lower end of the second cooling body is B, A/B is 1.1-1.5. [3] The single crystal pulling apparatus according to [1] or [2], The distance between the lower end of the second cooling body and the outer peripheral surface of the growing single crystal is 20-70 mm. Effects of the invention According to the present invention, a single crystal pulling apparatus capable of observing the liquid surface with excellent cooling performance of a single crystal can be provided. Drawings FIG. 1 is a cross-sectional view showing a single crystal pulling apparatus according to an embodiment of the present invention. Detailed Description Embodiments of the present invention will be described below by way of example with reference to the accompanying drawings. As shown in FIG. 1, in one embodiment of the present invention, a single crystal pulling apparatus 1 is a single crystal pulling apparatus 1 according to the Czochralski method, and comprises a crucible 3 (a double-layer crucible having a quartz crucible built therein) for storing a melt 4 as a material of a single crystal 2 such as silicon, a seed crystal pulling apparatus 6 for pulling a seed crystal 5 while rotating about a central axis O, the seed crystal 5 being brought into contact with a liquid surface 4a of the melt 4 at the start of growth of the single crystal 2 as a starting point of the grown single crystal 2, and a control apparatus 7 configured by a computer or the like for controlling a rotation speed and a pulling speed of the seed crystal 5 by the seed crystal pulling apparatus 6. The seed crystal pulling device 6 has a seed chuck 6a for holding the seed crystal 5, a wire rod 6b having one end connected to the seed chuck 6a, and a winding device 6c for winding up the wire rod 6b from the other end side. After immersing the lower end of the seed crystal 5 in the liquid surface 4a, the seed crystal 5 is rotated and raised to form a neck portion 2a at the lower end of the seed crystal 5 and a shoulder portion 2b having a gradually expanding diameter, and thereafter, a substantially cylindrical straight tube portion 2c centered on the central axis O is grown. In the present embodiment, a direction orthogonal to the central axis O is referred to as a radial direction, a direction around the central axis O is referred to as a circumferential direction, and a cross section orthogonal to the central axis O is refe