Device and method for measuring liquid level height of molten silicon in single crystal furnace

Abstract

The invention discloses a device and a method for measuring the liquid level height of molten silicon in a single crystal furnace, belonging to the technical field of semiconductor material detection. The device is characterized in that a crucible is arranged in a single crystal pulling furnace body; a conical heat insulation screen is arranged on the crucible in the single crystal pulling furnace body; an observation hole is formed in the top surface of the single crystal pulling furnace body, and through the observation hole, laser can enter the single crystal pulling furnace body and a photoelectric sensor can acquire an image; the optical axis of a lens is set to be perpendicular to the projection of a laser stripe on silicon liquid, the sum d' of the distance between one reference point and the laser stripe and the distance between the other reference point and the laser stripe is calculated, and the distance d between the lower edge of the heat insulation screen and the silicon liquid is calculated according to a geometric relation. According to the device and the method, laser is adopted as reference of measurement, and the laser stripe can be processed to be narrower, so that the measurement precision can be improved; the measurement precision is higher due to adoption of double reflection laser measurement; the laser incidence and the CCD (charge coupled device) imaging are carried out in a same incident hole, the laser is fixed together with a CCD, and the device disclosed by the invention lowers complexity in comparison with a method in which laser enters the single crystal pulling furnace body from a window and is received by the CCD from another window.

Description

technical field [0001] The invention relates to a device and a method for measuring the liquid level height of molten silicon in a single crystal furnace, belonging to the technical field of semiconductor material detection. Background technique [0002] Monocrystalline silicon is the raw material for manufacturing semiconductor silicon devices, and is used to manufacture high-power rectifiers, high-power transistors, diodes, switching devices, etc. Monocrystalline silicon is also a promising material in the development of energy. Crystalline silicon solar cells have developed rapidly in recent years and achieved large-scale industrialization. [0003] According to different crystal growth methods, single crystal silicon can be divided into Czochralski method (CZ), zone melting method (FZ) and epitaxy method. Single crystal silicon rods are grown by Czochralski method and zone melting method, and single crystal silicon thin films are grown by epitaxial method. Single cryst...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a device and method for measuring the liquid level height of molten silicon in a single crystal furnace. The present invention uses a laser double reflection method to measure the liquid level height of molten silicon to overcome the defects of the current conventional detection method, such as complex algorithms and low detection accuracy.

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