An anti-tilt support device for a quartz crucible used in semiconductor crystal pulling.

Abstract

This disclosure provides an anti-tilt support device for a quartz crucible used in semiconductor crystal pulling, relating to the field of semiconductor crystal growth equipment technology. The device includes a support platform, a height adjustment mechanism mounted on the support platform, and a clamping mechanism mounted on the height adjustment mechanism. The clamping mechanism employs a U-shaped rigid constraint node design. A single power source inside the drive box drives a vertical transmission rod, which in turn drives two horizontal lead screws to rotate synchronously via a rigidly enclosed bevel gear set, thereby causing the arc-shaped clamping plates on both sides to move synchronously towards the center. The U-shaped fixing plate serves as the core rigid element, providing multi-dimensional precision rotational support for the meshing parts of the transmission rod and the two lead screws, effectively eliminating gear slippage and shaft deformation during gear meshing. This disclosure significantly improves the verticality maintenance capability of the quartz crucible during single crystal growth and extends the equipment's service life.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor crystal growth equipment manufacturing technology, and in particular to an anti-tilting support device for a quartz crucible used for semiconductor crystal pulling. Background Technology

[0002] In the modern semiconductor materials industry, the Czochralski method is the most important process technology for preparing large-size, high-quality single-crystal silicon. This process involves loading high-purity polycrystalline silicon raw materials into a quartz crucible within a vacuum or inert gas-protected single-crystal furnace, heating it to over 1400°C using a graphite heater to melt it, then immersing a seed crystal into the melt. Under strictly controlled temperature and rotational pulling speeds, a single-crystal silicon rod is grown. In this process, the quartz crucible, as the core container supporting the silicon melt, has a decisive influence on the crystal growth quality due to its positional accuracy and orientation stability. As wafer diameters have increased from 8 inches to 12 inches and even larger, the amount of silicon material fed has increased dramatically, and the load on the quartz crucible and its support system often reaches hundreds of kilograms.

[0003] Currently, the installation and support of quartz crucibles mainly rely on manual operation or simple mechanical clamps. However, existing methods have several shortcomings. First, in related technologies, crucible placement often depends on the operator's experience, using visual inspection or a simple level for centering and leveling. Due to the weight and brittleness of large crucibles, manual operation makes it difficult to ensure that the crucible's rotation center is perfectly aligned with the center of the single-crystal furnace spindle, easily leading to initial installation errors. Second, existing mechanical clamping methods mostly employ linkage mechanisms or screw drives with single-end cantilever support. This existing method exposes significant structural defects when facing high-temperature and heavy-load conditions. Because the drive shaft and gears lack sufficient rigid support, the transmission components are prone to elastic deformation when clamping heavy objects, causing asynchronous movement of the left and right clamping arms, which in turn causes the crucible to become eccentric or tilted.

[0004] Specifically, the existing operating method has the following problems: the existing clamping mechanism lacks sufficient transmission rigidity, resulting in large gear meshing clearances and easy wear, making it impossible to guarantee a stable vertical clamping posture over a long period. In traditional bevel gear transmission designs, to avoid central space or simplify the structure, cantilever shafts are often used to mount the bevel gears. When the motor drives the drive wheel to rotate, the huge radial separation force and axial thrust generated by the bevel gear meshing act directly on the cantilever shaft, causing the axis to deviate. This deviation not only disrupts the correct meshing contact pattern of the gears, leading to "tooth breakage" or severe wear, but more critically, it causes lag and angular errors in the transmission chain, resulting in inconsistent screw angles on the two drive clamping plates, physically causing the initial installation tilt of the quartz crucible. Moreover, with the passage of time, this wear-induced tilt becomes increasingly severe, seriously affecting the crystallization rate and quality of monocrystalline silicon. Summary of the Invention

[0005] This disclosure provides an anti-tilting support device for a quartz crucible used in semiconductor crystal pulling. By introducing a U-shaped rigid constraint node structure, the problem of drive shaft deflection and gear backlash is fundamentally solved, achieving high-precision synchronous clamping and attitude maintenance.

[0006] The technical solution disclosed herein is implemented as follows: This disclosure provides an anti-tilt support device for a quartz crucible used in semiconductor crystal pulling, comprising: Support platform; A height adjustment mechanism is provided on the support platform for driving the load to move vertically. A clamping mechanism is fixedly disposed at the output end of the height adjustment mechanism for clamping and fixing the quartz crucible body; The clamping mechanism includes a drive box, a transmission rod disposed inside the drive box, and two lead screws; the transmission rod is rotatably mounted in the drive box in the vertical direction, and the two lead screws are symmetrically rotatably mounted in the drive box in the horizontal direction. A first conical transmission gear is fixedly installed on the transmission rod, and a second conical transmission gear is fixedly installed at the end of each of the two lead screws near the transmission rod. The first conical transmission gear meshes with the two second conical transmission gears simultaneously. A U-shaped fixing plate, integrally machined, is fixedly installed at the center of the drive box. The U-shaped fixing plate has two vertical sidewalls and a horizontal connecting part. The transmission rod passes through the horizontal connecting part of the U-shaped fixing plate and is rotatably connected to the horizontal connecting part. The inner ends of the two lead screws are respectively inserted into the two vertical sidewalls of the U-shaped fixing plate and are rotatably connected to the vertical sidewalls, so that the U-shaped fixing plate forms rigid support for the meshing area of ​​the first conical transmission gear and the two second conical transmission gears.

[0007] In some embodiments, the clamping mechanism further includes a second motor, which is fixedly mounted on the outer top surface of the drive box, and the output shaft of the second motor passes through the outer wall of the drive box and is fixedly connected to the top end of the transmission rod.

[0008] In some embodiments, the outer walls of both lead screws are threaded with threaded sleeves, and a connecting frame is fixedly connected to the outer side of the threaded sleeve. An arc-shaped clamping plate is fixedly provided at one end of each connecting frame extending to the outside of the drive box.

[0009] In some embodiments, the height adjustment mechanism includes a first threaded rod disposed inside the support platform and a movable cylinder threaded to the outside of the first threaded rod.

[0010] In some embodiments, the inner wall of the support platform is provided with a vertical guide groove, a guide plate is fixedly provided on one side of the movable cylinder, the guide plate is slidably embedded in the vertical guide groove, an L-shaped platform frame is fixedly connected to the side of the movable cylinder away from the guide plate, and the drive box is fixedly installed on the horizontal surface of the L-shaped platform frame.

[0011] In some embodiments, a first motor is fixedly mounted on the top of the support platform, the top end of the first threaded rod is connected to the output shaft of the first motor, and the first threaded rod is rotatably mounted on the side wall of the support platform through a first bearing.

[0012] In some embodiments, a clamping sensing system is also included, which includes a control panel disposed on the support platform and pressure sensors disposed on the arc-shaped clamping plates. The pressure sensors are arranged in an array on the inner sidewall of each arc-shaped clamping plate to detect multi-point pressure distribution data on the contact surface between the arc-shaped clamping plate and the quartz crucible body.

[0013] In some embodiments, the clamping sensing system further includes a processing module and an execution module integrated in the control panel. The processing module is configured to receive signals from the pressure sensor and calculate the pressure difference between the two arc-shaped clamping plates and the uniformity of the pressure distribution on one side. When the pressure difference exceeds a preset threshold or the uniformity of the pressure distribution is lower than a preset standard, the processing module controls the second motor to operate through the execution module to fine-tune the clamping force of the clamping mechanism.

[0014] In some embodiments, the U-shaped fixing plate is made of high-strength alloy steel, and bearing holes are machined on the two vertical sidewalls of the U-shaped fixing plate. The inner end of the lead screw is supported in the bearing hole by a radial thrust ball bearing. A third bearing is provided on the inner sidewalls of the left and right sidewalls of the drive box, and the outer end of the lead screw is supported in the third bearing.

[0015] In some embodiments, the inner surface of the arc-shaped clamping plate is attached with a high-temperature resistant flexible buffer layer, which is selected from graphite felt, carbon fiber fabric or high-temperature resistant rubber.

[0016] This disclosure provides an anti-tilting support device for a quartz crucible used in semiconductor crystal pulling. By setting a U-shaped fixing plate, a "rigid support" is formed at the meshing node of the first bevel gear and the two second bevel gears. In other words, the joint of the transmission rod and the two lead screws (i.e., the power distribution center) is tightly "held" together, forming an extremely stable rigid node. This ensures that all radial and axial forces generated by gear meshing are confined within the highly rigid small closed loop of the U-shaped fixing plate, and are no longer transmitted to the long cantilevered outer wall of the drive box, thereby eliminating bending deformation of the transmission shaft. During high-speed start-up or heavy-load clamping, the U-shaped fixing plate effectively resists the huge separation force generated by the bevel gear meshing, preventing any slight twisting or bending of the transmission rod and lead screws. This ensures that the bevel gears always transmit power through surface contact on the designed pitch circle, rather than edge contact, thereby virtually eliminating gear wear and transmission backlash. This high-rigidity transmission ensures absolute synchronization of the rotation angles of the lead screws on both sides, enabling the arc-shaped clamping plates on both sides to be aligned and clamped with micron-level precision. This fundamentally prevents initial crucible tilting caused by mechanical deviations. Because the U-shaped fixing plate optimizes the stress state, the drive shaft and bearings no longer bear additional bending moment loads, significantly reducing gear wear. This allows the device to maintain high-precision operation for extended periods even in the harsh environment of semiconductor manufacturing, characterized by high temperatures and continuous operation, reducing downtime for maintenance and spare parts replacement costs due to equipment failure. Furthermore, it achieves automatic precision centering and stable clamping of the quartz crucible. With the precise control of the servo motor, this mechanical structure ensures that the quartz crucible automatically aligns itself the moment it is clamped, eliminating the need for repeated manual adjustments and improving production efficiency and process consistency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall three-dimensional structure of an anti-tilting support device for a quartz crucible used in semiconductor crystal pulling, as disclosed in this disclosure; Figure 2 This is a frontal cross-sectional view of the device disclosed herein, clearly showing the internal connection relationship between the lead screw drive of the height adjustment mechanism and the clamping mechanism; Figure 3 This is a top sectional view of the clamping mechanism in this disclosure, which focuses on the support structure of the U-shaped fixing plate inside the drive box for the bevel gear set and the inner end of the lead screw. Figure 4 This is a three-dimensional schematic diagram of the independent structure of the U-shaped fixing piece in this disclosure, showing the layout of its mounting holes and bearing seat holes; Figure 5 For this disclosure Figure 2 The enlarged view at point A in the middle shows in detail the fit between the guide plate and the vertical guide groove; Figure 6 This is a logic block diagram of the clamping sensing system in this disclosure. Detailed Implementation

[0018] The technical solutions in this disclosure will now be clearly and completely described with reference to the accompanying drawings.

[0019] See Figure 1 and Figure 2 This disclosure provides an anti-tilting support device for a quartz crucible used in semiconductor crystal pulling, mainly composed of a support platform 1, a height adjustment mechanism 2, a clamping mechanism 3, and a control panel 4. The support platform 1 serves as the base of the entire device and is typically made of high-strength cast iron, undergoing aging treatment to eliminate internal stress and ensure dimensional stability under high-temperature conditions. The bottom of the support platform 1 is equipped with anchor bolt interfaces for rigidly fixing it to the furnace bottom lifting shaft or rotating platform of the single crystal furnace. The overall shape of the support platform 1 is a hollow box structure, providing installation space and a guiding reference for the internal height adjustment components.

[0020] The height adjustment mechanism 2 drives the quartz crucible body 6 to move precisely vertically within the single crystal furnace, in accordance with changes in the melt level during crystal growth. For example... Figure 2 As shown, two bearing seats are precision-machined on the inner left side of the support platform 1, each housing a first bearing 201. To withstand the heavy axial load (including the weight of the crucible, silicon material, and clamping mechanism), the first bearings 201 are preferably configured with a combination of thrust ball bearings and deep groove ball bearings, or directly with paired tapered roller bearings. A vertically arranged first threaded rod 202 is rotatably connected between the two first bearings 201. The first threaded rod 202 is a high-precision ball screw, with its surface subjected to high-frequency quenching and precision grinding, achieving a hardness of HRC60 or higher to ensure efficient transmission and wear resistance.

[0021] A first motor 203 is fixedly mounted on the top plane of the support platform 1 via a motor mount. The first motor 203 is an AC servo motor with a power-off brake function. The motor output shaft is directly connected to the top end of the first threaded rod 202 via a rigid coupling. When the first motor 203 rotates, it drives the first threaded rod 202 to rotate in its original position.

[0022] A movable cylinder 204, threadedly engaged with the first threaded rod 202, is fitted around its exterior. A ball nut is embedded inside the movable cylinder 204. To convert the rotational motion of the first threaded rod 202 into the linear lifting motion of the movable cylinder 204, the circumferential degree of freedom of the movable cylinder 204 must be restricted. Therefore, as follows... Figure 5As shown in detail, a long strip-shaped guide plate 205 is integrally formed or welded onto the outer left side of the movable cylinder 204. The cross-section of the guide plate 205 is rectangular or dovetail-shaped. Correspondingly, a deep groove-shaped vertical guide slot is formed on the inner wall of the support platform 1 along the vertical direction. The guide plate 205 is precisely embedded in the guide slot, and a wear-resistant lining plate (such as a polytetrafluoroethylene strip) is provided between them, with the fitting gap controlled within 0.05mm. This guide design not only plays a role in preventing rotation, but more importantly, it acts as a sliding fulcrum, effectively bearing the cantilever bending moment brought by the L-shaped platform frame 206, greatly enhancing the stability of the lifting process and preventing possible swaying and impact during lifting or lowering.

[0023] An L-shaped platform frame 206 is fixedly connected to the right end of the movable cylinder 204. The L-shaped platform frame 206 is made of high-strength alloy steel, and the upper surface of its horizontal arm is precision milled to serve as the mounting reference surface for the clamping mechanism 3.

[0024] Clamping mechanism 3 is the core component for achieving the anti-tilt function. See also Figure 3 and Figure 4 The clamping mechanism 3 includes a fully enclosed drive box 301, which is made of aluminum alloy or stainless steel to prevent silicon dust from entering. The drive box 301 is fixed to the L-shaped platform frame 206 by bolts.

[0025] Inside the drive box 301, a sophisticated T-gear transmission system is constructed. Vertically, a transmission rod 303, made of 40Cr alloy structural steel, is positioned. The upper and lower ends of the transmission rod 303 are supported on the top and bottom walls of the drive box 301 via second bearings 302, respectively. A second motor 304 (servo motor) is mounted on the top exterior of the drive box 301, its output shaft passing through a sealing ring and connected to the transmission rod 303. A keyed drive first bevel transmission gear 309 is connected to the middle of the transmission rod 303. This gear uses Gleason gears, is made of 20CrMnTi, and is precision ground after carburizing and quenching to ensure smooth meshing and low noise.

[0026] Two lead screws 307 are symmetrically arranged in the horizontal direction. The outer end of each lead screw 307 (the end furthest from the center) is supported on the left and right side walls of the drive box 301 by a third bearing 306. In order to solve the problem of insufficient rigidity caused by the cantilever force on the inner end of the lead screw in the traditional design, this disclosure introduces a key component - a U-shaped fixing plate 305 - at the geometric center of the drive box 301.

[0027] like Figure 4As shown, the U-shaped fixing plate 305 is a one-piece machined steel component, shaped like an inverted "U" or a door frame. Its bottom is rigidly connected to the base plate of the drive box 301 by high-strength bolts. The U-shaped fixing plate 305 has two thick vertical sidewalls, on which bearing holes with high coaxiality are machined. The inner ends (the ends closer to the center) of the two lead screws 307 are respectively inserted into these two bearing holes and are rotatably supported by high-load-bearing capacity inner bearings (such as needle roller bearings or angular contact ball bearings).

[0028] In this way, the two lead screws 307 are transformed from a "cantilever beam" into a "simply supported beam" or "double-ended fixed beam" structure, resulting in an exponential increase in their bending resistance. The transmission rod 303 passes through the horizontal connecting part of the U-shaped fixed plate 305 (or the space between the two vertical walls). The first conical transmission gear 309 is located in the internal space of the U-shaped fixed plate 305. The inner ends of the two lead screws 307 are respectively equipped with driven second conical transmission gears 310, which are also located within the "embrace" of the U-shaped fixed plate 305 and mesh with the left and right sides of the first conical transmission gear 309, respectively.

[0029] This design creates a "mechanically enclosed cage" for the U-shaped retaining plate 305. When the gears generate enormous radial repulsive and axial thrust at high speed, these forces are not transmitted and cause deformation of the drive housing wall; instead, they are directly absorbed and balanced by the rigid U-shaped retaining plate 305. This ensures that the geometric positions of the three bevel gears are permanently locked, completely eliminating changes in meshing clearance caused by shaft deformation, thereby guaranteeing the absolute synchronicity of the rotation of the two lead screws 307.

[0030] Each lead screw 307 is fitted with a threaded nut 308. To achieve centering and clamping, the two lead screws 307 are designed with one left-handed and the other right-handed (or opposite rotations can be achieved through gear arrangement). The threaded nut 308 is connected to a connecting frame 311, which extends to the outside through an elongated hole in the side wall of the drive box 301, and an arc-shaped clamping plate 312 is fixed at its end. The inner radius of the arc-shaped clamping plate 312 is consistent with the outer diameter of the quartz crucible body 6, and a high-temperature resistant flexible buffer layer is attached to its inner surface. This buffer layer is selected from graphite felt, carbon fiber fabric, or high-temperature resistant rubber to increase friction and protect the quartz surface.

[0031] To further address the minute attitude shifts during the crystal pulling process, the device disclosed herein also incorporates a clamping sensing system. For example... Figure 6 As shown, the system includes a human interaction module 61, a processing module (MCU or PLC) 62, and an execution module (motor driver) 63 integrated in the control panel 4.

[0032] The system also includes a sensing module. Instead of simply placing a single sensor on the inner wall of each arc-shaped clamping plate 312, an array of pressure sensors 5 is arranged. For example, a 3×3 nine-point array is used, employing high-temperature resistant piezoresistive or capacitive pressure sensors. This array distribution can generate a pressure cloud map on the clamping surface. The working logic of the clamping sensing system is described in detail below.

[0033] First, initial centering is achieved. When the second motor 304 drives the arc-shaped clamping plate 312 to contact the crucible, the processing module 62 monitors the total pressure value of the sensor arrays on both sides. Thanks to the rigid synchronization of the mechanical structure, the pressure on both sides should rise almost simultaneously. If a significant time difference occurs, the system alarms to prompt a check of the crucible's placement.

[0034] Next is dynamic attitude correction. During the crystal pulling process, the processing module 62 collects pressure data at a high frequency (e.g., 50Hz). If the crucible tilts slightly due to thermal expansion or stress release, it will cause a change in the pressure distribution. For example, if the pressure difference between the left and right clamping plates exceeds a preset threshold, or if the pressure of the upper row of sensors on the left clamping plate increases and the pressure of the lower row decreases, while the opposite is true for the right side, this clearly indicates that the crucible has tilted.

[0035] Finally, there is closed-loop feedback. Once the pressure difference pattern detected exceeds the preset threshold, the processing module 62 immediately instructs the execution module 63 to control the second motor 304 for fine-tuning. For example, the motor slightly reverses and loosens (e.g., 0.1mm), allowing the crucible to naturally reset using gravity, and then quickly re-clamps it to the target pressure value. This dynamic "breathing" clamping strategy effectively eliminates accumulated stress and posture deviations during the process.

[0036] In summary, this disclosure solves the inherent installation tilt and wear problems through the extreme rigidity design of the mechanical structure (U-shaped fixing piece), and solves the acquired process drift problem through the intelligent sensing and control system. The two complement each other and perfectly solve the long-standing problem of quartz crucible support in the semiconductor crystal pulling field.

[0037] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An anti-tilting support device for a quartz crucible used in semiconductor crystal pulling, characterized in that, include: Support platform; A height adjustment mechanism is provided on the support platform for driving the load to move vertically. A clamping mechanism is fixedly disposed at the output end of the height adjustment mechanism for clamping and fixing the quartz crucible body; The clamping mechanism includes a drive box, a transmission rod disposed inside the drive box, and two lead screws; the transmission rod is rotatably mounted in the drive box in the vertical direction, and the two lead screws are symmetrically rotatably mounted in the drive box in the horizontal direction. A first conical transmission gear is fixedly installed on the transmission rod, and a second conical transmission gear is fixedly installed at the end of each of the two lead screws near the transmission rod. The first conical transmission gear meshes with the two second conical transmission gears simultaneously. A U-shaped fixing plate, integrally machined, is fixedly installed at the center of the drive box. The U-shaped fixing plate has two vertical sidewalls and a horizontal connecting part. The transmission rod passes through the horizontal connecting part of the U-shaped fixing plate and is rotatably connected to the horizontal connecting part. The inner ends of the two lead screws are respectively inserted into the two vertical sidewalls of the U-shaped fixing plate and are rotatably connected to the vertical sidewalls, so that the U-shaped fixing plate forms rigid support for the meshing area of ​​the first conical transmission gear and the two second conical transmission gears.

2. The anti-tilting support device for a quartz crucible used for semiconductor crystal pulling according to claim 1, characterized in that, The clamping mechanism also includes a second motor, which is fixedly mounted on the outer top surface of the drive box, and the output shaft of the second motor passes through the outer wall of the drive box and is fixedly connected to the top end of the transmission rod.

3. The anti-tilting support device for a quartz crucible used for semiconductor crystal pulling according to claim 2, characterized in that, Both lead screws have threaded sleeves connected to their outer walls. A connecting frame is fixedly connected to the outer side of the threaded sleeve. An arc-shaped clamping plate is fixedly installed at one end of each connecting frame that extends to the outside of the drive box.

4. The anti-tilting support device for a quartz crucible for semiconductor crystal pulling according to claim 1, characterized in that, The height adjustment mechanism includes a first threaded rod disposed inside the support platform and a movable cylinder threaded to the outside of the first threaded rod.

5. The anti-tilting support device for a quartz crucible for semiconductor crystal pulling according to claim 4, characterized in that, The inner wall of the support platform is provided with a vertical guide groove. A guide plate is fixedly provided on one side of the movable cylinder. The guide plate is slidably embedded in the vertical guide groove. An L-shaped platform frame is fixedly connected to the side of the movable cylinder away from the guide plate. The drive box is fixedly installed on the horizontal surface of the L-shaped platform frame.

6. The anti-tilting support device for a quartz crucible used for semiconductor crystal pulling according to claim 4, characterized in that, A first motor is fixedly installed on the top of the support platform. The top end of the first threaded rod is connected to the output shaft of the first motor. The first threaded rod is rotatably mounted on the side wall of the support platform through a first bearing.

7. The anti-tilting support device for a quartz crucible for semiconductor crystal pulling according to claim 3, characterized in that, It also includes a clamping sensing system, which includes a control panel mounted on the support platform and pressure sensors mounted on the arc-shaped clamping plates. The pressure sensors are arranged in an array on the inner sidewall of each arc-shaped clamping plate and are used to detect multi-point pressure distribution data on the contact surface between the arc-shaped clamping plate and the quartz crucible body.

8. The anti-tilting support device for a quartz crucible for semiconductor crystal pulling according to claim 7, characterized in that, The clamping sensing system also includes a processing module and an execution module integrated in the control panel. The processing module is configured to receive signals from the pressure sensor and calculate the pressure difference between the two arc-shaped clamping plates and the uniformity of the pressure distribution on one side. When the pressure difference exceeds a preset threshold or the uniformity of the pressure distribution is lower than a preset standard, the processing module controls the second motor to operate through the execution module to fine-tune the clamping force of the clamping mechanism.

9. The anti-tilting support device for a quartz crucible for semiconductor crystal pulling according to claim 1, characterized in that, The U-shaped fixing plate is made of high-strength alloy steel. Bearing holes are machined on the two vertical side walls of the U-shaped fixing plate. The inner end of the lead screw is supported in the bearing hole by a radial thrust ball bearing. A third bearing is provided on the inner side of the left and right side walls of the drive box. The outer end of the lead screw is supported in the third bearing.

10. The anti-tilting support device for a quartz crucible for semiconductor crystal pulling according to claim 3, characterized in that, The inner surface of the arc-shaped clamping plate is covered with a high-temperature resistant flexible buffer layer, which is selected from graphite felt, carbon fiber fabric or high-temperature resistant rubber.

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