Device and method for detecting deviation in moving process of heat shield of single crystal furnace

Abstract

The invention discloses a device and a method for detecting deviation in a moving process of a heat shield of a single crystal furnace, a furnace cover is arranged above a main furnace chamber, so that the furnace cover forms a sealing cover for a cavity in the main furnace chamber, an auxiliary furnace chamber is arranged above the furnace cover, and communication with the cavity in the main furnace chamber is formed through the auxiliary furnace chamber; the bottom where the right servo driving piece is located is connected with a right lifting rod penetrating through the furnace cover and extends into an inner cavity of the main furnace chamber, so that the left lifting rod and the right lifting rod are connected and pulled to the two sides of a heat shield located in the inner cavity of the main furnace chamber correspondingly. The right lifting rod located on the right side is synchronously driven through a flexible shaft so as to achieve lifting motion in the vertical direction. On the basis of lifting mechanism hardware, the synchronous detection mechanisms above the lead screws on the two sides of the lifting mechanism are utilized, and certain specific detection algorithms are added, so that horizontal deviation detection is achieved, and the accident risk can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of single crystal furnace preparation, and in particular relates to a detection device and method based on the deviation occurring during the movement of a heat screen of a single crystal furnace. Background Art

[0002] A single crystal furnace is a device used to grow single crystal materials. It is widely used in semiconductors, optoelectronics, materials science and other fields. Single crystal furnaces usually use a melting method to grow single crystal materials. First, the raw materials (such as silicon, germanium, gallium nitride, etc.) are heated to a molten state to form a uniform liquid phase. Then, by controlling the temperature gradient and cooling rate, the atoms or molecules in the molten liquid are arranged according to a specific lattice structure to gradually form a single crystal. Temperature control in a single crystal furnace is very critical. The temperature in the furnace usually needs to be kept above the melting point in order to maintain the liquid phase of the material, while having an appropriate temperature gradient to promote the growth of the crystal. The temperature distribution can be precisely controlled by adjusting the heating elements and cooling system.

[0003] After the single crystal furnace is dismantled, loaded or the silicon material is melted, the heat shield will be raised and lowered. The heat shield is kept horizontal by two lifting rods. Under normal circumstances, the heat shield will move vertically downward under the linkage of the lifting mechanism. If there is a problem with the left lifting mechanism or the right lifting mechanism (slipping of the soft shaft), the height of the lifting rods on the left and right sides will be out of sync. If it continues to move downward at this time, it will eventually lead to danger or accidents. If the motor output shaft slips or there is a problem with the soft shafts of the left and right lifting mechanisms, it will also cause accidents. In addition, the reliability of the mechanical limit device is affected by wear and aging, which may lead to false alarms or missed alarms. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a detection device and a detection method based on the offset occurring during the movement of the heat shield of a single crystal furnace, thereby solving the above-mentioned technical problems existing in the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A detection device based on the deviation of the heat shield of a single crystal furnace during its movement, comprising a left lifting mechanism and a right lifting mechanism, a furnace cover is arranged above the main furnace chamber, so that the furnace cover forms a sealing cover for the cavity inside the main furnace chamber, and an auxiliary furnace chamber is arranged above the furnace cover, and the auxiliary furnace chamber is connected to the cavity inside the main furnace chamber through the auxiliary furnace chamber;

[0007] The left lifting mechanism comprises a left servo drive and a left lifting rod, wherein the left servo drive is located at the upper part of the furnace cover, passes through the furnace cover through the lower part of the left lifting rod and extends into the inner cavity of the main furnace chamber;

[0008] The left servo drive is connected to the top of the furnace cover extended out of the right servo drive of the right lifting mechanism through a flexible shaft, and the bottom of the right servo drive is connected to the right lifting rod penetrating the furnace cover and extending into the inner cavity of the main furnace chamber, so that the left lifting rod and the right lifting rod respectively form a connection and pulling on both sides of the heat shield located in the inner cavity of the main furnace chamber. When the left lifting rod is driven to lift by the left servo drive, the right lifting rod located on the right side is synchronously driven through the flexible shaft to realize the lifting movement in the vertical direction.

[0009] Further, the left servo drive member includes a drive motor, a screw rod, a synchronous detection wheel and a synchronous detection sensor, and determines that the stroke of the screw rod is L;

[0010] The driving motor is located at the lower part where the screw rod is located, and is rotatably connected to a synchronous detection wheel at the top of the screw rod. The driving motor drives the self-rotation of the screw rod to realize the axial rotation of the synchronous detection wheel at the top of the screw rod. A synchronous detection sensor is arranged at the top side position where the screw rod is located, and the rotation state of the synchronous detection wheel is detected by the synchronous detection sensor.

[0011] Further, the right servo drive member includes a screw rod, a synchronous detection wheel and a synchronous detection sensor, and determines that the stroke of the screw rod is L;

[0012] The screw rod of the right servo drive component is connected to the screw rod of the left servo drive component through a flexible shaft to achieve synchronous drive. The self-rotation of the screw rod is driven by the drive motor to achieve the rotation of the synchronous detection wheel on the top axis of the screw rod. A synchronous detection sensor is arranged on the top side of the screw rod, and the rotation state of the synchronous detection wheel is detected by the synchronous detection sensor.

[0013] Furthermore, the synchronous detection wheel is in a disc-shaped structure as a whole, and N groups of grooves are evenly distributed on the periphery of the synchronous detection wheel. The grooves are evenly distributed along the periphery of the synchronous detection wheel, and the grooves between two adjacent groups form a protrusion;

[0014] When the protrusion of the synchronous detection wheel blocks the signal of the synchronous detection sensor, it will be triggered, and when the groove of the synchronous detection wheel blocks the signal of the synchronous detection sensor, it will not be triggered.

[0015] Furthermore, the main furnace chamber is located in the middle of the cavity where the heat screen is located, and the left lifting mechanism and the right lifting mechanism simultaneously realize the connection and grabbing of the two sides of the heat screen respectively.

[0016] The detection method based on the deviation during the movement of the single crystal furnace comprises the following steps:

[0017] The number of signals triggered by the synchronous detection sensors on the left lifting mechanism and the right lifting mechanism are counted as S and S respectively, and the difference is calculated. When the difference exceeds the set value A,

[0018] That is, when |SS|>A, the screw deviation of the left lifting mechanism and the right lifting mechanism has exceeded the normal operation deviation, and the system will issue an alarm.

[0019] The detection method based on the deviation during the movement of the single crystal furnace comprises the following steps:

[0020] When the heat screen moves a certain distance m, the synchronous detection signal on the synchronous detection sensor is theoretically triggered P times, and the difference between the actual triggering number Q and the theoretical triggering number P is compared with the set value B.

[0021] The specific formula is:

[0022]

[0023] When |QP|>B, there is a deviation between the set distance and the actual distance, and the system issues an alarm.

[0024] Further, the following steps are included:

[0025] When the synchronous detection signal on the synchronous detection sensor is triggered P times, the heat screen will definitely move a distance of m;

[0026] The actual running distance is T, and the difference between it and the theoretical running distance m is compared with the set value C;

[0027] When |Tm|>C, there is a deviation between the set distance and the actual distance, and the system issues an alarm.

[0028] Beneficial effects of the present invention:

[0029] 1. The present invention adopts a synchronous detection mechanism of the left and right lifting mechanisms, and through the combination of multiple sensors and algorithms, can monitor the state of the heat shield in real time and accurately. This technical solution not only improves the stability of the heat shield, but also effectively reduces the production risk caused by deviation, and has broad application prospects. The device should be able to monitor the lifting state of the heat shield in real time and give an alarm in time when deviation occurs, so as to ensure the normal operation of the single crystal furnace and the quality of crystal growth.

[0030] 2. The detection method adopted by this device can give a timely warning when the heat screen deviates to prevent major accidents.

[0031] 3. The present invention utilizes a combination of a synchronous detection wheel and a synchronous detection sensor to accurately determine whether the heat shield is offset by calculating the difference between the trigger signal and the actual moving distance. In addition, multiple protection algorithms are set to ensure that an alarm can be given in time when any detection mechanism is triggered, thereby achieving comprehensive monitoring of the heat shield offset. This design not only improves the accuracy and reliability of detection, but also provides a new idea for the intelligent management of single crystal furnaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0033] Figure 1 is a schematic diagram of the overall side structure of an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of the overall top view structure of an embodiment of the present invention;

[0035] Figure 3 is a schematic structural diagram of a left servo drive component according to an embodiment of the present invention;

[0036] Figure 4 It is a structural schematic diagram of the connection state of the synchronous detection wheel and the synchronous detection sensor in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The technical scheme in the embodiment of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiment of the present invention. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] like Figure 1 , Figure 2 As shown, an embodiment of the present invention provides a detection device based on the displacement of the heat shield of a single crystal furnace during movement, comprising a left lifting mechanism 1 and a right lifting mechanism 2. A furnace cover 4 is arranged above the main furnace chamber 3, so that the furnace cover 4 forms a sealing cover for the cavity inside the main furnace chamber 3, and an auxiliary furnace chamber 5 is arranged above the furnace cover 4, and a connection with the cavity inside the main furnace chamber 3 is formed through the auxiliary furnace chamber 5; a heat shield 6 is arranged in the cavity inside the main furnace chamber 3, and is connected with the left lifting mechanism 1 and the right lifting mechanism 2 on both sides of the heat shield 6 (that is, the heat shield 6 in the main furnace chamber 3 is located in the middle of the cavity, and the left lifting mechanism 1 and the right lifting mechanism 2 are synchronously connected and grasped on both sides of the heat shield 6), and the left lifting mechanism 1 and the right lifting mechanism 2 synchronously perform actions, so that the heat shield 6 always maintains a horizontal state during the lifting process and moves in the vertical direction.

[0039] The left lifting mechanism 1 includes a left servo drive 11 and a left lifting rod 12 (similarly, the right lifting mechanism 2 includes a right servo drive 21 and a right lifting rod 22), and the left servo drive 11 and the right lifting mechanism 2 are located on the upper part of the furnace cover 4 (symmetrically arranged), and the lower part of the left lifting rod 12 penetrates the furnace cover 4 and extends to the inner cavity of the main furnace chamber 3. This connection method can form a stable connection to the heat shield 6.

[0040] like Figure 3 , Figure 4 As shown, the left servo drive member 11 includes a drive motor 111, a screw rod 112, a synchronous detection wheel 113 and a synchronous detection sensor 114, and determines that the stroke of the screw rod 112 is L;

[0041] The driving motor 111 is located at the lower part where the screw rod 112 is located, and is rotatably connected to a synchronous detection wheel 113 at the top of the screw rod 112. The driving motor 111 drives the self-rotation of the screw rod 112 to realize the axial rotation of the synchronous detection wheel 113 at the top of the screw rod 112. A synchronous detection sensor 114 is set at the top side position where the screw rod 112 is located, and the rotation state of the synchronous detection wheel 113 is detected by the synchronous detection sensor 114.

[0042] The synchronous detection wheel 113 is in a disc-shaped structure as a whole, and N groups of grooves 1131 are evenly distributed on the outer periphery of the synchronous detection wheel 113 (in this case, the grooves 1131 are evenly distributed along the outer periphery of the synchronous detection wheel 113), and a protrusion 1132 is formed between two adjacent groups of grooves 1131, that is, there are multiple groups distributed on the outer periphery of the detection wheel 113 as a whole;

[0043] When the protrusion 1132 of the synchronous detection wheel 113 blocks the signal of the synchronous detection sensor 114, it will be triggered. When the groove 1131 of the synchronous detection wheel 113 blocks the signal of the synchronous detection sensor 114, it will not be triggered. That is, by combining the number of triggers and the parameter comparison of N, the actual number of rotations of the screw rod 112 can be obtained.

[0044] The right servo drive 21 has the same structure as the left servo drive 11 (not shown, but can be referred to Figure 3 ), whenever there is a lack of drive, the drive from the right servo driver 21 is connected through the left servo driver 11, and the adopted structure includes a screw rod 112, a synchronous detection wheel 113 and a synchronous detection sensor 114, and the stroke of the screw rod 112 is determined to be L (this stroke is consistent with the stroke of the screw rod 112 on the left servo driver 11).

[0045] The screw rod 112 of the right servo drive component 21 is connected to the screw rod 112 of the left servo drive component 11 through the flexible shaft 401 to realize synchronous drive. The self-rotation of the screw rod 112 is driven by the driving motor 111 to realize the rotation of the synchronous detection wheel 113 on the top axis of the screw rod 112. A synchronous detection sensor 114 is set at the top side position where the screw rod 112 is located, and the rotation state of the synchronous detection wheel 113 is detected by the synchronous detection sensor 114.

[0046] During specific use, the left servo drive 11 is connected to the top of the furnace cover 4 extended out of the right servo drive 21 of the right lifting mechanism 2 through the flexible shaft 401, and the bottom of the right servo drive 21 is connected to the right lifting rod 22 that penetrates the furnace cover 4 and extends into the inner cavity of the main furnace chamber 3, so that the left lifting rod 12 and the right lifting rod 22 respectively form a connection and pulling on both sides of the heat shield 6 located in the inner cavity of the main furnace chamber 3. When the left lifting rod 12 is driven to lift by the left servo drive 11, the right lifting rod 22 located on the right side is synchronously driven through the flexible shaft 401 to realize synchronous lifting and lowering movement in the vertical direction (the power on the left servo drive 11 can be synchronously output to the right servo drive 21, so as to ensure that the actions of the left and right lifting mechanisms are executed synchronously, and finally the heat shield always remains in a horizontal state during the lifting process and moves in the vertical direction).

[0047] The detection method based on the deviation of the heat shield during the movement of the single crystal furnace includes the following steps:

[0048] Coaxial detection

[0049] The number of signals triggered by the synchronous detection sensors 114 on the left lifting mechanism 1 and the right lifting mechanism 2 is counted as S1 and S2 respectively, and the difference is calculated;

[0050] When the difference is less than or equal to A, that is, |S1-S2|≤A, the deviation of the screw rod 112 where the left lifting mechanism 1 and the right lifting mechanism 2 are located does not exceed the normal operation deviation, and the system operates normally without any alarm indication;

[0051] When the difference exceeds the set value A, that is, |S1-S2|>A, the deviation of the screw rod 112 where the left lifting mechanism 1 and the right lifting mechanism 2 are located has exceeded the normal operation deviation, and the system will issue an alarm.

[0052] This method can avoid the situation where the left and right lifting mechanisms are out of sync due to a flexible shaft failure.

[0053] In addition, the detection method based on the offset of the heat shield during the movement of the single crystal furnace includes the following steps:

[0054] Synchronous stroke detection

[0055] When the heat screen 6 moves a certain distance m, the synchronous detection signal on the synchronous detection sensor 114 is theoretically triggered P times. However, the actual triggering number Q is compared with the theoretical triggering number P and the set value B. When the P difference is greater than the set value B, the system alarms.

[0056] The specific formula is:

[0057]

[0058] When |QP|≤B, the P difference is less than or equal to the set value B, the system works normally and no alarm is issued.

[0059] When |QP|>B, there is a deviation between the set distance and the actual distance, and the P difference is greater than the set value B, the system will issue an alarm.

[0060] Synchronous signal detection (another detection method) includes the following steps:

[0061] When the synchronous detection signal on the synchronous detection sensor 114 is triggered P times, the heat shield 6 will definitely move a distance m;

[0062] The actual running distance is T, and the difference between it and the theoretical running distance m is compared with the set value C;

[0063] When |Tm|>C, there is a deviation between the set distance and the actual distance, that is, when the difference with the theoretical running distance m is greater than the set value C, the system will issue an alarm.

[0064] This method can avoid the risk of the lifting mechanism sliding down by itself due to loosening of the servo motor output shaft coupling.

[0065] The present invention utilizes the synchronous detection wheels and synchronous detection limit on the upper parts of the left and right lifting mechanisms, and according to certain judgment logic, through system calculation, finally determines whether the guide tube is offset. The key technical solutions and innovative points of the present invention are as follows:

[0066] Hardware parameter basis: Based on the lead screw lead L of the left and right lifting mechanisms, and the synchronous detection wheel on the top of the screw, the number of protrusions of the synchronous detection wheel is N. When the screw rotates one circle, the sensor will detect N synchronization signals, and the thermal screen will move L length.

[0067] The present invention is based on hardware and has a triple protection algorithm. The three algorithms are independent of each other. As long as one of the detections is triggered, an alarm can be issued.

[0068] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A detection device based on the deviation of the heat shield during the movement of a single crystal furnace, comprising a left lifting mechanism (1) and a right lifting mechanism (2), characterized in that: A furnace cover (4) is arranged above the main furnace chamber (3), so that the furnace cover (4) forms a sealing cover for the cavity inside the main furnace chamber (3); and a secondary furnace chamber (5) is arranged above the furnace cover (4), and the secondary furnace chamber (5) is connected to the cavity inside the main furnace chamber (3); The left lifting mechanism (1) comprises a left servo drive member (11) and a left lifting rod (12); the left servo drive member (11) is located at the upper part of the furnace cover (4), passes through the lower part of the left lifting rod (12), penetrates the furnace cover (4) and extends into the inner cavity of the main furnace chamber (3); The left servo drive (11) is connected to the top of the furnace cover (4) extended by the right servo drive (21) of the right lifting mechanism (2) through a flexible shaft (401), and the bottom of the right servo drive (21) is connected to the right lifting rod (22) penetrating the furnace cover (4) and extending into the inner cavity of the main furnace chamber (3), so that the left lifting rod (12) and the right lifting rod (22) respectively form a connection and pulling on both sides of the heat shield (6) located in the inner cavity of the main furnace chamber (3). When the left lifting rod (12) is driven to lift by the left servo drive (11), the right lifting rod (22) located on the right side is synchronously driven through the flexible shaft (401) to realize the lifting movement in the vertical direction.

2. The detection device based on the deviation of the heat shield during the movement of the single crystal furnace according to claim 1 is characterized in that: The left servo drive member (11) comprises a drive motor (111), a screw rod (112), a synchronous detection wheel (113) and a synchronous detection sensor (114), and determines that the stroke of the screw rod (112) is L; The drive motor (111) is located at the lower part where the screw rod (112) is located, and a synchronous detection wheel (113) is rotatably connected to the top of the screw rod (112). The drive motor (111) drives the screw rod (112) to rotate, so that the synchronous detection wheel (113) rotates axially at the top of the screw rod (112). A synchronous detection sensor (114) is arranged at the side position of the top where the screw rod (112) is located, and the rotation state of the synchronous detection wheel (113) is detected by the synchronous detection sensor (114).

3. The detection device based on the deviation of the heat shield during the movement of the single crystal furnace according to claim 1 is characterized in that: The right servo drive member (21) comprises a screw rod (112), a synchronous detection wheel (113) and a synchronous detection sensor (114), and determines that the stroke of the screw rod (112) is L; The screw rod (112) of the right servo drive member (21) is connected to the screw rod (112) of the left servo drive member (11) via a flexible shaft (401) to achieve synchronous drive. The screw rod (112) is driven to rotate by the driving motor (111) to achieve the rotation of the synchronous detection wheel (113) at the top axis of the screw rod (112). A synchronous detection sensor (114) is arranged at the top side of the screw rod (112). The rotation state of the synchronous detection wheel (113) is detected by the synchronous detection sensor (114).

4. The detection device based on the deviation of the heat shield during the movement of the single crystal furnace according to claim 2 is characterized in that: The synchronous detection wheel (113) is in a disc-shaped structure as a whole, and N groups of grooves (1131) are evenly distributed on the periphery of the synchronous detection wheel (113), and the grooves (1131) are evenly distributed along the periphery of the synchronous detection wheel (113), and the grooves (1131) between two adjacent groups form a protrusion (1132); When the protrusion (1132) of the synchronous detection wheel (113) blocks the signal of the synchronous detection sensor (114), it will be triggered, and when the groove (1131) of the synchronous detection wheel (113) blocks the signal of the synchronous detection sensor (114), it will not be triggered.

5. The detection device based on the deviation of the heat shield during the movement of the single crystal furnace according to claim 2 is characterized in that: The heat shield (6) in the main furnace chamber (3) is located in the middle of the cavity, and the left lifting mechanism (1) and the right lifting mechanism (2) are simultaneously connected and grasped on both sides of the heat shield (6).

6. The detection method based on the deviation of the heat shield during the movement of the single crystal furnace according to any one of claims 1 to 5, characterized in that: The following steps are involved: The number of signals triggered by the synchronous detection sensors (114) on the left lifting mechanism (1) and the right lifting mechanism (2) is counted as S1 and S2 respectively, and the difference is calculated. When the difference exceeds the set value A, That is, when |S1-S2|>A, the deviation of the screw rod (112) where the left lifting mechanism (1) and the right lifting mechanism (2) are located has exceeded the normal operation deviation, and the system will issue an alarm prompt.

7. The detection method based on the deviation of the heat shield during the movement of the single crystal furnace according to any one of claims 1 to 5, characterized in that: The following steps are involved: When the heat shield (6) moves a certain distance m, the synchronous detection signal on the synchronous detection sensor (114) is theoretically triggered P times, and the difference between the actual triggering number Q and the theoretical triggering number P is compared with the set value B. The specific formula is: When |QP|>B, there is a deviation between the set distance and the actual distance, and the system issues an alarm.

8. The method for detecting the offset of the heat shield during the movement of a single crystal furnace according to any one of claim 7, characterized in that: The following steps are involved: When the synchronous detection signal on the synchronous detection sensor (114) is triggered P times, the heat shield (6) moves a distance m; The actual running distance is T, and the difference between it and the theoretical running distance m is compared with the set value C; When |Tm|>C, there is a deviation between the set distance and the actual distance, and the system issues an alarm.

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