Zone-melting silicon single crystal rod drawing furnace

Abstract

The utility model provides a zone-melting silicon single crystal rod drawing furnace, and relates to the technical field of silicon single crystal rod drawing. The crystal bar drawing mechanism is arranged in the furnace body; a crystal bar growth monitoring mechanism; numerical control equipment; the furnace body is internally provided with at least two drawing spaces which are communicated with each other, and crystal bar drawing mechanisms are arranged in the at least two drawing spaces; the crystal bar growth monitoring mechanism is electrically connected with the numerical control equipment, and the numerical control equipment can control the crystal bar drawing mechanism to act. According to the crystal bar drawing furnace, the at least two drawing spaces communicated with each other are arranged in the furnace body, and the crystal bar drawing mechanisms are arranged in the at least two drawing spaces, so that a plurality of crystal bars can be drawn at one time, the efficiency is higher, the speed is higher, and the cost is lower. The growth vigor of the crystal bar is monitored through the crystal bar growth vigor monitoring mechanism, real-time growth vigor data of the crystal bar is transmitted to the numerical control equipment, the numerical control equipment judges the next stage according to a pre-established database and controls corresponding equipment to execute actions, and therefore whole-process automation is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of single crystal silicon rod drawing, in particular to a zone melting single crystal silicon rod drawing furnace. Background Art

[0002] The small zone melting single crystal silicon rod pulling furnace currently used in the market can only pull a single crystal rod (single crystal silicon rod is referred to as crystal rod) at a time and cannot achieve automatic pulling. The steps for use are: ① Load a seed crystal and a mother rod into the furnace; ② Manually draw a vacuum for 3 times; ③ Manually fill with argon; ④ Click the touch screen to heat the lower end of the mother rod; ⑤ Click the touch screen to fuse the seed crystal and the mother rod; ⑥ During pulling, the personnel observe the situation in the furnace with the naked eye and control the pulling process according to the situation in the furnace; ⑦ Dismantle the furnace.

[0003] The small zone melting single crystal silicon rod pulling furnace currently used in the market has the following defects:

[0004] 1. High cost: Since each drawing process requires silicon material, compressed air, argon, circulating water, desalted water, alcohol and other materials (pulling 3 crystal rods requires three furnace starts, and correspondingly there are three material consumptions), only a single crystal rod is drawn at a time, which has the defect of high cost.

[0005] 2. Low efficiency: One furnace can only pull one crystal rod at a time, which is inefficient.

[0006] 3. Slow speed: It takes about 1 hour to draw a crystal rod, and the speed of mass production is slow.

[0007] 4. There are safety risks. During the drawing process, personnel need to observe the situation inside the furnace. The light inside the furnace irritates the eyes. If the eyes are exposed to strong light for a long time, they will over-adjust and easily suffer from visual fatigue, retinal hemorrhage, and even induce occupational diseases such as cataracts, keratitis, conjunctivitis, and blepharitis. Utility Model Content

[0008] In view of the above situation, the utility model provides a zone-melting single crystal silicon rod pulling furnace, aiming to point out at least one defect of the existing small zone-melting single crystal silicon rod pulling furnace based on the above background technology.

[0009] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0010] The utility model provides a zone melting single crystal silicon rod pulling furnace, comprising:

[0011] Furnace body;

[0012] A crystal rod pulling mechanism is arranged in the furnace body;

[0013] A crystal rod growth monitoring mechanism, used to monitor the growth of the pulled crystal rod;

[0014] CNC equipment;

[0015] in:

[0016] The furnace body is provided with at least two mutually connected drawing spaces, and at least two of the drawing spaces are provided with a crystal rod drawing mechanism;

[0017] The crystal rod growth monitoring mechanism is electrically connected to the numerical control device, and the numerical control device can control the action of the crystal rod pulling mechanism.

[0018] In some embodiments of the present invention, the crystal rod growth monitoring mechanism includes an infrared probe.

[0019] In some embodiments of the present invention, there are three drawing spaces.

[0020] In some embodiments of the present utility model, the crystal rod pulling mechanism includes a first limiting structure and a second limiting structure respectively disposed above and below;

[0021] The first limiting structure is used to install the mother rod and can drive the mother rod to move longitudinally;

[0022] The second limiting structure is used to install the seed crystal, and can drive the seed crystal to move longitudinally and rotate around the axis of the seed crystal itself;

[0023] Also includes a first heating element and a second heating element;

[0024] The first heating element is movably disposed below the mother rod seat in a transverse direction and is used for heating the lower end of the mother rod;

[0025] The second heating element is fixedly arranged between the first limiting structure and the second limiting structure and is located on the growth path of the crystal rod.

[0026] In some embodiments of the present invention, the first limiting structure includes:

[0027] A first movable member is connected to the upper part of the furnace body and can drive the mother rod to move longitudinally;

[0028] A female rod seat is connected to the lower end of the first movable member, and a plurality of claws that can gather or spread out are distributed at the bottom of the female rod seat;

[0029] A fastener is used to bring the claws together.

[0030] In some embodiments of the present invention, the second limiting structure includes:

[0031] The seed crystal seat is arranged at the upper end of the second movable member and is used for mounting the seed crystal.

[0032] The second movable member is connected to the lower part of the furnace body and can drive the seed crystal to move longitudinally and rotate around the axis of the seed crystal itself.

[0033] In some embodiments of the present invention, the first heating element includes a quartz ring.

[0034] In some embodiments of the present invention, the second heating element includes a high-frequency coil.

[0035] In some embodiments of the utility model, a vacuum pumping mechanism and an argon gas flushing mechanism connected to the furnace body are also included.

[0036] In some embodiments of the utility model, the argon gas flushing mechanism includes an argon gas flushing pipeline, and a regulating valve is provided on the argon gas flushing pipeline;

[0037] A remote pressure gauge is arranged on the furnace body, the output end of the remote pressure gauge is electrically connected to the input end of the numerical control device, and the output end of the numerical control device is electrically connected to the control end of the regulating valve.

[0038] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0039] 1. By providing at least two interconnected drawing spaces in the furnace body, and at least two of the drawing spaces have a crystal rod drawing mechanism, it is possible to pull multiple crystal rods at one time, which is more efficient, faster and less costly.

[0040] 2. The growth of the crystal ingot is monitored by the crystal ingot growth monitoring mechanism, and the real-time growth data of the crystal ingot is transmitted to the CNC equipment. The CNC equipment determines the next stage (such as necking and shoulder release) according to the pre-established database, and controls the corresponding equipment to perform actions, thereby realizing full automation. In this way, the operator does not need to observe the situation in the furnace throughout the process, avoiding the adverse effect of strong light on the operator's eyes.

[0041] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is a schematic diagram of the structure of a zone melting single crystal silicon rod pulling furnace.

[0044] icon:

[0045] 1-furnace body, 11-drawing space,

[0046] 21-quartz ring, 22-high frequency coil, 231-first movable part, 232-mother rod seat, 233-claw, 241-seed crystal seat, 242-second movable part,

[0047] 3- Infrared probe,

[0048] 4-seed crystal,

[0049] 5- mother rod,

[0050] 6-Crystal rod. DETAILED DESCRIPTION

[0051] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can appreciate, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention.

[0052] In the description of the embodiments of the present invention, it should be understood that the terms "longitudinal", "lateral", "upper", "lower", "bottom", "inner", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present invention.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0054] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0055] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0056] See also Figure 1 This embodiment provides a zone melting single crystal silicon rod pulling furnace, including a furnace body 1, a crystal rod pulling mechanism and a crystal rod growth monitoring mechanism.

[0057] The furnace body 1 has an openable and closable furnace door (not shown in the figure), and has at least two interconnected drawing spaces 11 in the furnace body 1. In this embodiment, preferably, there are three drawing spaces 11, so that the space in the furnace can be maximized without changing the external dimensions of the existing equipment.

[0058] The crystal rod pulling mechanism is arranged in the furnace body 1, and at least two pulling spaces 11 have the crystal rod pulling mechanism; the crystal rod pulling mechanism includes a first heating element and a second heating element, and a first limiting structure and a second limiting structure respectively arranged above and below.

[0059] The first limiting structure is used to install the mother rod 5 and can drive the mother rod 5 to move longitudinally. In a specific implementation scenario, the first limiting structure includes a first movable member 231, a mother rod seat 232 and a fastener.

[0060] The first movable member 231 is connected to the upper part of the furnace body 1 , and the first movable member 231 is transmission-connected to a power source (not shown in the figure) to drive the mother rod 5 to move longitudinally.

[0061] The mother rod seat 232 is connected to the lower end of the first movable member 231 , and a plurality of claws 233 that can gather together or spread apart are evenly distributed on the bottom of the mother rod seat 232 ; the claws 233 can fix the upper end of the mother rod 5 when gathered together.

[0062] The fastener (not shown in the figure) is used to bring the claws 233 together; the fastener includes, for example, a tungsten wire, and the claws 233 are brought together by tightening the tungsten wire.

[0063] The second limiting structure is used to install the seed crystal 4, and can drive the seed crystal 4 to move longitudinally and rotate around the axis of the seed crystal 4. In a specific implementation scenario, the second limiting structure includes a seed crystal seat 241 and a second movable member 242.

[0064] The seed crystal seat 241 is disposed at the upper end of the second movable member 242 and is used to mount the seed crystal 4. In a specific implementation scenario, the seed crystal 4 is mounted in the same manner as the mother rod 5.

[0065] The second movable member 242 is connected to the lower part of the furnace body 1 , and the second movable member 242 is drivingly connected to a power source (not shown in the figure) to drive the seed crystal 4 to move longitudinally and rotate around the axis of the seed crystal 4 itself.

[0066] The first heating element is disposed below the mother rod holder 232 in a lateral movable manner, and is used to heat the lower end of the mother rod 5 to facilitate the melting of the seed crystal 4. In a specific implementation scenario, the first heating element includes a quartz ring 21.

[0067] The second heating element is fixedly disposed between the first limiting structure and the second limiting structure and is located on the growth path of the crystal rod 6; the crystal rod 6 passes through the second heating element during the pulling and growing process. In a specific implementation scenario, the second heating element includes a high-frequency coil 22.

[0068] The crystal ingot growth monitoring mechanism is used to monitor the growth of the drawn crystal ingot 6, that is, to monitor the height change of the drawn crystal ingot 6. The crystal ingot growth monitoring mechanism includes, for example, an infrared probe 3, which is electrically connected to a numerical control device (not shown in the figure) to transmit the real-time growth data of the crystal ingot 6 to the numerical control device. The numerical control device determines the next stage (such as necking and shoulder release) according to a pre-established database, and controls the corresponding equipment (such as the crystal ingot pulling mechanism, etc.) to perform the corresponding action, thereby realizing full automation.

[0069] The zone melting single crystal silicon rod pulling furnace further comprises a vacuum pumping mechanism (not shown in the figure) and an argon gas flushing mechanism (not shown in the figure) connected to the furnace body 1 .

[0070] The vacuum pumping mechanism is used to vacuum the furnace body 1, and the vacuum pumping mechanism includes a vacuum pump and matching pipelines and a solenoid valve.

[0071] The argon flushing mechanism includes an argon flushing pipeline, which is used to flush argon gas into the furnace body 1 to a positive pressure (0.04Mpa ~ 0.1Mpa) in the furnace body 1 after the furnace body 1 is evacuated, so as to meet the requirements of the drawing process of the crystal rod 6. The furnace body 1 is also provided with an exhaust valve, which needs to be opened to exhaust gas before opening the furnace.

[0072] A regulating valve is provided on the argon gas pipeline, and a remote pressure gauge is provided on the furnace body 1. The output end of the remote pressure gauge is electrically connected to the input end of the numerical control device, and the output end of the numerical control device is electrically connected to the control end of the regulating valve, so as to automatically adjust the pressure in the furnace body 1 so that the pressure in the furnace body 1 is 0.04Mpa ~ 0.1Mpa before the furnace is opened.

[0073] The steps of using the above-mentioned zone melting single crystal silicon rod pulling furnace include:

[0074] Step 1: Load the mother rod 5 and the materials into the furnace → operate the CNC equipment to start the vacuum pump to evacuate the furnace body 1. When the pressure in the furnace is below 3pa, close the solenoid valve to stop the vacuum pump → fill with argon to positive pressure (0.04Mpa ~ 0.1Mpa), and repeat the replacement three times;

[0075] Step 2: bring the quartz ring 21 close to the lower end of the mother rod 5 → adjust the current to 0.5-1A to make the quartz ring 21 red. After 20 minutes, the mother rod 5 turns red → raise the first movable member 231 to make the mother rod 5 higher than the quartz ring 211cm;

[0076] Step 3: Remove the quartz ring 21 and lower the first movable member 231 to a position 225 mm from the mother rod 5 to the high-frequency coil.

[0077] Step 4: Increase the voltage of the high-frequency coil 22 → When the molten zone of the mother rod 5 sags in a water drop shape, the mother rod 5 and the seed crystal 4 are welded;

[0078] Step 5, synchronously raise the first movable member 231 and the second movable member 242 by 0.5 cm → forward rotation of the second movable member 242 by 25 rpm → the second movable member 242 slowly drops by 4 mm / min → the first movable member 231 slowly increases from 0.1 mm / min to 0.6 mm / min (neck shrinkage), the second movable member 242 moves 30 mm → the first movable member 231 slowly increases from 1 mm / min to 3 mm / min (shoulder release) and gradually decreases to 1.30~1.45 mm / min → the second movable member 242 has a diameter of 120 mm → stop the first movable member 231 slowly → the second movable member 242 slowly rises by 6~10 mm → the first movable member 231 rises to break the crystal rod 6 and reduces the power at the same time → stop the second movable member 242 slowly and the rotation speed;

[0079] Step 6. Turn off the power stop button on the operating column;

[0080] Step 7: Cool naturally for 15 minutes, control the vacuum pump → control the solenoid valve → loosen the bolts on the furnace door;

[0081] Step 8: Control the solenoid valve → control the vacuum pump → open the exhaust valve;

[0082] Step 9. Wear a mask, degreased cloth gloves, and disposable PE gloves → Open the furnace door to take out the single crystal sample, then take out the tailings, and close the furnace door.

[0083] In combination with the above content, this embodiment has at least the following beneficial effects:

[0084] First, by providing at least two interconnected pulling spaces 11 in the furnace body 1, and at least two pulling spaces 11 have a crystal rod pulling mechanism, it is possible to pull multiple crystal rods 6 at one time, with higher efficiency, faster speed and lower cost. In particular, providing three pulling spaces 11 can maximize the use of the furnace space without changing the external dimensions of the existing equipment.

[0085] Second, the growth of the crystal ingot 6 is monitored by the crystal ingot growth monitoring mechanism, and the real-time growth data of the crystal ingot 6 is transmitted to the numerical control device. The numerical control device determines the next stage (such as necking and shouldering) according to the pre-established database, and controls the corresponding equipment to perform actions, thereby realizing full automation. In this way, the operator does not need to observe the situation in the furnace throughout the process, avoiding the adverse effect of strong light on the operator's eyes.

[0086] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. In the absence of conflicts, the embodiments of the present application and the features in the embodiments may be combined with each other at will. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A zone melting single crystal silicon rod pulling furnace, characterized in that: include: Furnace body; A crystal rod pulling mechanism is arranged in the furnace body; A crystal rod growth monitoring mechanism, used to monitor the growth of the pulled crystal rod; CNC equipment; in: The furnace body is provided with at least two mutually connected pulling spaces, and at least two of the pulling spaces are provided with the crystal rod pulling mechanism; The crystal ingot growth monitoring mechanism is electrically connected to the numerical control device, and the numerical control device can control the action of the crystal ingot pulling mechanism.

2. The zone melting single crystal silicon rod pulling furnace according to claim 1, characterized in that: The crystal rod growth monitoring mechanism comprises an infrared probe.

3. The zone melting single crystal silicon rod pulling furnace according to claim 1, characterized in that: There are three drawing spaces.

4. The zone melting single crystal silicon rod pulling furnace according to claim 1, characterized in that: The crystal rod pulling mechanism comprises a first limiting structure and a second limiting structure respectively arranged above and below; The first limiting structure is used to install the mother rod and can drive the mother rod to move longitudinally; The second limiting structure is used to install the seed crystal, and can drive the seed crystal to move longitudinally and rotate around the axis of the seed crystal itself; Also includes a first heating element and a second heating element; The first heating element can be laterally movably arranged below the first limiting structure, and is used to heat the lower end of the mother rod; The second heating element is fixedly arranged between the first limiting structure and the second limiting structure and is located on a growth path of the crystal rod.

5. The zone melting single crystal silicon rod pulling furnace according to claim 4, characterized in that: The first limiting structure comprises: A first movable member is connected to the upper part of the furnace body and can drive the mother rod to move longitudinally; A mother rod seat connected to the lower end of the first movable member, wherein a plurality of claws capable of gathering or spreading together are distributed at the bottom of the mother rod seat; A fastener is used to bring the claws together.

6. The zone melting single crystal silicon rod pulling furnace according to claim 4, characterized in that: The second limiting structure comprises: A seed crystal seat, arranged at the upper end of the second movable member, for mounting the seed crystal; The second movable member is connected to the lower part of the furnace body and can drive the seed crystal to move longitudinally and rotate around the axis of the seed crystal itself.

7. The zone melting single crystal silicon rod pulling furnace according to claim 4, characterized in that: The first heating element includes a quartz ring.

8. The zone melting single crystal silicon rod pulling furnace according to claim 4, characterized in that: The second heating element includes a high frequency coil.

9. The zone melting single crystal silicon rod pulling furnace according to any one of claims 1 to 8, characterized in that: It also includes a vacuum pumping mechanism and an argon gas flushing mechanism connected to the furnace body.

10. The zone-melting single crystal silicon rod pulling furnace according to claim 9, characterized in that: The argon gas flushing mechanism comprises an argon gas flushing pipeline, and a regulating valve is arranged on the argon gas flushing pipeline; A remote pressure gauge is provided on the furnace body, the output end of the remote pressure gauge is electrically connected to the input end of the numerical control device, and the output end of the numerical control device is electrically connected to the control end of the regulating valve.

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