Silicon liquid level detection device for single crystal furnace

Abstract

The utility model provides a silicon liquid level detection device for a single crystal furnace, which is arranged on a mounting plate of a lifting head at the top of the single crystal furnace, a detection hole is formed in the mounting plate, a laser range finder is arranged above the detection hole, and the laser range finder can transmit a laser beam to the liquid level of the silicon liquid through the detection hole to detect the liquid level of the silicon liquid. The silicon liquid level detection device has the beneficial effects that the silicon liquid level of the single crystal furnace is accurately detected in the crystal pulling process, the crystal pulling quality is ensured, the structure is simple, and the operation is convenient and fast.

Description

Technical Field

[0001] The utility model belongs to the technical field of single crystal silicon production, in particular to a single crystal furnace silicon liquid level detection device. Background Art

[0002] In the process of pulling single crystal silicon, the silicon material is first placed in a quartz crucible, and the silicon material is melted into silicon liquid at high temperature in a vacuum, and then the silicon liquid is cooled to the critical temperature of crystallization, and then the seed crystal is extended above the silicon liquid and in contact with the silicon liquid. By slowly lifting the seed crystal and lowering the crucible, the silicon liquid will gradually condense under the seed crystal to form single crystal silicon.

[0003] How to control the crystallization temperature, pulling speed and silicon liquid level in the single crystal furnace is a very important process step for pulling high-quality single crystal silicon rods. In the actual production process, the silicon liquid level is difficult to accurately control due to the change in the crystallization speed of the silicon liquid. Since the silicon liquid level will decrease with the increase in the volume of the silicon rod, in the crystal pulling process, the crucible position is usually raised to compensate for the decrease in the silicon liquid level. Therefore, it is necessary to accurately detect the silicon liquid level. However, since the quartz crucible is located inside the single crystal furnace, the single crystal furnace is in an extreme high temperature and low pressure environment during the crystal pulling process, which brings great difficulty to the detection of the silicon liquid level. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a single crystal furnace silicon liquid level detection device, which effectively solves the technical problem that the single crystal furnace silicon liquid level is difficult to detect and overcomes the shortcomings of the prior art.

[0005] The technical solution adopted by the utility model is: a single crystal furnace silicon liquid level detection device is arranged on the mounting plate of the pulling head at the top of the single crystal furnace, the mounting plate is provided with a detection hole, a laser rangefinder is arranged above the detection hole, and the laser rangefinder can emit a laser beam to the silicon liquid surface through the detection hole to detect the silicon liquid level.

[0006] Furthermore, a perspective window is provided on the detection hole.

[0007] Furthermore, a first positioning groove is provided at the top of the detection hole for placing the perspective window.

[0008] Furthermore, a first sealing ring is provided at the bottom of the first positioning groove.

[0009] Furthermore, a first sealing ring groove is provided at the bottom of the first positioning groove for accommodating the first sealing ring.

[0010] Furthermore, a fixing flange is provided on the upper portion of the perspective window and is detachably connected to the mounting plate.

[0011] Furthermore, the fixing flange is provided with a second positioning groove adapted to fit the top of the perspective window.

[0012] Furthermore, a second sealing ring is provided at the bottom of the second positioning groove.

[0013] Furthermore, a second sealing ring groove is provided at the bottom of the second positioning groove for accommodating the second sealing ring.

[0014] Furthermore, a fixing bracket is provided on the mounting plate for setting the laser rangefinder.

[0015] The advantages and positive effects of the utility model are as follows: due to the adoption of the above technical scheme, accurate detection of the silicon liquid level of the single crystal furnace during the crystal pulling process is achieved, thereby ensuring the crystal pulling quality, and the structure is simple and the operation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the installation of a single crystal furnace silicon liquid level detection device according to an embodiment of the utility model.

[0017] Figure 2 It is a structural enlarged diagram A of a single crystal furnace silicon liquid level detection device according to an embodiment of the utility model.

[0018] In the figure:

[0019] 1. Mounting plate 2. Detection hole 3. Laser rangefinder

[0020] 4. Laser beam 5. Silicon liquid level 6. Transparent window

[0021] 7. First positioning groove 8. First sealing ring 9. First sealing ring groove

[0022] 10. Fixed flange 11. Second positioning groove 12. Second sealing ring

[0023] 13. Second sealing groove 14. Fixed bracket 15. Quartz crucible

[0024] 16. Single crystal furnace auxiliary chamber 17. Auxiliary chamber furnace wall 18. Single crystal silicon rod

[0025] 19. Single crystal furnace main chamber 20. Single crystal silicon liquid DETAILED DESCRIPTION

[0026] The embodiment of the utility model provides a device for detecting the liquid level of silicon liquid in a single crystal furnace. The embodiment of the utility model is described below in conjunction with the accompanying drawings.

[0027] In the description of the embodiments of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "set" and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood by specific circumstances.

[0028] like Figure 1 and 2 As shown, the embodiment of the utility model is a single crystal furnace silicon liquid level detection device, which is arranged on the mounting plate 1 of the top lifting head of the single crystal furnace, and the mounting plate 1 is provided with a detection hole 2, and a laser rangefinder 3 is arranged above the detection hole 2. In order to ensure that the laser rangefinder 3 can work normally, the laser rangefinder 3 needs to be installed outside the single crystal furnace. The transmitting end of the laser rangefinder 3 can vertically emit a laser beam 4 to the silicon liquid level 5 through the detection hole 2, and the laser beam 4 is reflected by the silicon liquid level 5 back to the receiving end of the laser rangefinder 3, so as to detect the silicon liquid level.

[0029] During the crystal pulling process, it is necessary to prevent the atmosphere outside the furnace from entering the single crystal furnace, and at the same time, it is necessary to ensure that the laser beam 4 can pass through, so a perspective window 6 is provided on the detection hole 2. The shape of the perspective window 6 is not limited and is adapted to the detection hole 2. Preferably, the perspective window 6 is made of tempered glass. Due to the pressure difference between the inside and outside of the furnace, the use of tempered glass can ensure that it will not break and can ensure that the laser beam 4 can pass through smoothly.

[0030] Preferably, in order to facilitate positioning of the perspective window 6, a first positioning groove 7 is provided at the top of the detection hole 2, which is adapted to the bottom of the perspective window 6 and is used to place the perspective window 6. The shapes of the perspective window 6 and the first positioning groove 7 are not limited. Preferably, the shapes of the perspective window 6 and the first positioning groove 7 are circular. The height of the first positioning groove 7 is less than the thickness of the perspective window 6.

[0031] Preferably, in order to ensure sealing, a first sealing ring 8 is provided at the bottom of the first positioning groove 7, and the perspective window 6 is placed on the upper part of the first sealing ring 8. The material of the first sealing ring 8 needs to be resistant to high temperatures, and high temperature resistant silicone or tetrafluoroethylene material can be used.

[0032] Preferably, in order to facilitate positioning of the first sealing ring 8 , a first sealing ring groove 9 is provided at the bottom of the first positioning groove 7 for placing the first sealing ring 8 , and the first sealing ring groove 9 is adapted to the first sealing ring 8 .

[0033] Specifically, in order to facilitate fixing of the perspective window 6, a fixing flange 10 is provided above the perspective window 6. The fixing flange 10 is detachably connected to the mounting plate 1 by bolts, so as to fix the perspective window 6 on the detection hole 2.

[0034] Preferably, a second positioning groove 11 is provided on a side of the fixing flange 10 close to the perspective window 6 , and is adapted to the top of the perspective window 6 .

[0035] Preferably, in order to further ensure the sealing performance, a second sealing ring 12 is provided at the bottom of the second positioning groove 11, and the top of the perspective window 6 contacts the second sealing ring 12. The material of the second sealing ring 12 needs to be resistant to high temperatures, and high temperature resistant silicone or tetrafluoroethylene material can be used.

[0036] Preferably, in order to facilitate positioning of the second sealing ring 12 , a second sealing ring groove 13 is provided at the bottom of the second positioning groove 11 for placing the second sealing ring 12 , and the second sealing ring groove 13 is adapted to the second sealing ring 12 .

[0037] In order to facilitate the installation of the laser rangefinder 3 and enable the laser beam 4 to be vertically projected toward the silicon liquid level 5 through the perspective window 6, a fixed bracket 14 is provided on the mounting plate 1, and the laser rangefinder 3 is mounted on the fixed bracket 14. The specific form of the fixed bracket 14 is not limited. In some embodiments, the fixed bracket 14 is a split structure and is evenly arranged along the circumference of the fixed flange 10. The bottom of the fixed bracket 14 is fixedly connected to the mounting plate 1 by bolts, and the laser rangefinder 3 is fixed to the top of the fixed bracket 14, so that the transmitting end and the receiving end of the laser rangefinder 3 are directly opposite to the detection hole 2, ensuring that the laser beam 4 can avoid the auxiliary chamber furnace wall 17 of the single crystal furnace and the single crystal silicon rod 18 being pulled.

[0038] Preferably, the laser rangefinder 3 adopts a laser phase rangefinder. The transmitting end emits a continuous laser wave with a stable frequency. This laser beam is suitable for precise measurement because it has very certain wavelength and phase characteristics. The emitted laser usually passes through a modulator to modulate the phase of the light wave at a specific frequency. This modulation changes the phase of the light wave so that the light wave carries a specific mark during propagation. The modulated laser wave is emitted to the target object and then reflected back by the target object. The reflected laser is compared with a reference beam (the same laser without being reflected by the target) for phase comparison. Since the reflected light undergoes a phase change during the process of going back and forth to the target object, the total phase change of the light wave can be calculated by comparing the phase difference of the two beams. According to the total phase change of the light wave and the modulation frequency of the laser, the total distance of the laser going back and forth to the target object can be calculated. The laser phase rangefinder has higher measurement accuracy than the laser pulse rangefinder. The laser phase rangefinder is a prior art and will not be described in detail here.

[0039] Embodiment: A silicon liquid level detection device for a single crystal furnace is arranged on a mounting plate 1 of a lifting head at the top of the single crystal furnace. A circular detection hole 2 with a diameter of 60 mm is opened on the mounting plate 1. A laser rangefinder 3 is arranged above the detection hole 2. The laser rangefinder 3 adopts a laser phase rangefinder, with a range greater than 10 m and an accuracy guaranteed within ±0.1 mm. A tempered glass perspective window 6 is installed on the detection hole 2. A first positioning groove 7 is arranged at the top of the detection hole 2, which is adapted to the bottom of the perspective window 6 and is used to place the perspective window 6. The perspective window 6 and the first positioning groove 7 are circular in shape. The height of the first positioning groove 7 is less than the thickness of the perspective window 6. A first sealing ring groove 9 is arranged at the bottom of the first positioning groove 7, which is used to place the first sealing ring 8. A fixing flange 10 is arranged above the perspective window 6. The fixing flange 10 is detachably connected to the mounting plate 1 by bolts. A second positioning groove 11 is arranged on the side of the fixing flange 10 close to the perspective window 6, which is adapted to the top of the perspective window 6. A second sealing ring groove 13 is provided at the bottom of the second positioning groove 11 for placing the second sealing ring 12. Four fixing brackets 14 are evenly arranged along the circumference of the fixing flange 10. The bottom of the fixing bracket 14 is fixedly connected to the mounting plate 1 by bolts, and the laser rangefinder 3 is fixed to the top of the fixing bracket 14. The first sealing ring 8 and the second sealing ring 12 are both made of silicone.

[0040] After fixing the laser rangefinder 3, connect the power supply. After the silicon material in the single crystal furnace is completely melted into silicon liquid, during the crystal pulling process, the transmitting end of the laser rangefinder 3 vertically transmits the laser beam 4 to the silicon liquid level 5 through the perspective window 6, and the silicon liquid level 5 reflects the laser beam 4 back to the receiving end of the laser rangefinder 3, and calculates the distance from the laser rangefinder 3 to the position of the silicon liquid level 5, thereby detecting the change of the silicon liquid level. The laser rangefinder 3 transmits the detected data to the controller, and the controller obtains the lifting amount that the quartz crucible 15 needs to compensate through process calculation and comparison, thereby achieving the purpose of controlling the silicon liquid level.

[0041] The advantages and positive effects of the utility model are:

[0042] By adopting the above technical solution, the liquid level of silicon liquid in the single crystal furnace can be accurately detected during the crystal pulling process, thereby ensuring the quality of crystal pulling, with a simple structure and convenient operation.

[0043] The above is a detailed description of the embodiments of the utility model, but the contents are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of application of the utility model should still fall within the scope of the patent coverage of the utility model.

Claims

1. A single crystal furnace silicon liquid level detection device, arranged on the mounting plate of the top pulling head of the single crystal furnace, characterized in that: A detection hole is provided on the mounting plate, and a laser rangefinder is provided above the detection hole. The laser rangefinder can emit a laser beam to the silicon liquid surface through the detection hole to detect the silicon liquid level.

2. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 1, characterized in that: A perspective window is provided on the detection hole.

3. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 2, characterized in that: A first positioning groove is provided on the top of the detection hole for placing the perspective window.

4. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 3, characterized in that: A first sealing ring is provided at the bottom of the first positioning groove.

5. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 4, characterized in that: A first sealing ring groove is provided at the bottom of the first positioning groove for accommodating the first sealing ring.

6. A single crystal furnace silicon liquid level detection device according to any one of claims 2 to 5, characterized in that: A fixing flange is provided on the upper part of the perspective window and is detachably connected to the mounting plate.

7. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 6, characterized in that: The fixing flange is provided with a second positioning groove which is matched with the top of the perspective window.

8. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 7, characterized in that: A second sealing ring is provided at the bottom of the second positioning groove.

9. The device for detecting the level of silicon liquid in a single crystal furnace according to claim 8, characterized in that: A second sealing ring groove is provided at the bottom of the second positioning groove for accommodating the second sealing ring.

10. A single crystal furnace silicon liquid level detection device according to any one of claims 1-5 and 7-9, characterized in that: The mounting plate is provided with a fixing bracket for setting the laser rangefinder.

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