Apparatus and method for manufacturing quartz ring

Abstract

The application discloses a quartz ring preparation device and method. The device comprises a furnace body, a rotating assembly, a heating assembly, a mold and a temperature measuring assembly. The furnace body forms a heating cavity and is provided with an opening; the rotating assembly can rotate through the opening and comprises a rotating driving member, a bottom plate and a central rod; the heating assembly comprises a side wall outer coil and a bottom plate inner heating body; the heating body generates heat by alternating current of the inductor coil; and the mold is coaxially arranged on the central rod. In the method, a central hole cylindrical quartz raw material sleeve is arranged on the central rod, is lifted into the heating cavity, is inductively heated and rotated in an inert atmosphere, and softened quartz is caused to sink into the mold under the action of centrifugal force and gravity to be formed, cooled, demolded and cut to obtain the quartz ring. The scheme has high material utilization rate and good size consistency and is suitable for semiconductor etching.

Description

Technical Field

[0001] This application relates to the field of inorganic non-metallic material forming and high-temperature thermal processing technology, specifically to a quartz ring preparation apparatus and method. Background Technology

[0002] Quartz ring components commonly used in semiconductor etching equipment require high purity, low metallic impurities, low bubble defects, and good dimensional consistency. Existing feasible synthetic quartz ring fabrication technologies mainly include quartz ingot hollowing and quartz sand melting. Hollowing out synthetic quartz ingots is a common approach, but this method is limited by the characteristics of quartz ingot fabrication processes, resulting in bubbles and inclusions. Furthermore, hollowing out rings produces a large amount of excess material in both inner and outer rings due to variations in quartz ring specifications, leading to typically low material utilization. Quartz sand melting requires expensive synthetic quartz sand or high-purity melting equipment, resulting in higher overall costs. Some pressing or casting methods also suffer from difficulties in demolding, insufficient mold life, or limited shape accuracy.

[0003] Existing publicly available solutions include designs for preparing quartz cylinders from molten quartz sand or pressing molten quartz into cylinders, but these still struggle to simultaneously achieve high material utilization, consistent forming, and maintainable equipment. Other solutions involve directly depositing quartz rings using a central rod at the center of the deposition chamber, but these present challenges in adapting to the production capacity and process conditions of high-purity deposition processes. Therefore, it is necessary to propose a new quartz ring preparation apparatus and method to improve material utilization and reduce preparation costs while ensuring forming quality. Summary of the Invention

[0004] This application aims to provide an apparatus and method for preparing quartz rings, in order to solve the problems of low material utilization, high cost, insufficient forming consistency and difficulty in stable control of the process in the prior art for preparing synthetic quartz rings.

[0005] To achieve the above objectives, this application adopts the following technical solution.

[0006] In a first aspect, this application provides an apparatus for preparing quartz rings, comprising a furnace body, a rotating assembly, a heating assembly, a mold, and a temperature measuring assembly. The furnace body has side walls and a top plate, which together form a heating cavity. The furnace body has an opening away from the top plate, connecting the heating cavity to the external environment. The rotating assembly rotatably passes through the opening and includes a rotating drive, a base plate, and a central rod. The rotating drive is connected to the base plate, which movably passes through the opening. The central rod is located on the side of the base plate facing the heating cavity, and the rotating drive drives the base plate to rotate. The heating assembly includes a coil and a heating element. The coil is located on the side wall away from the heating cavity, and the heating element is located on the side of the base plate facing the heating cavity. The heating element senses the alternating current in the coil, thereby generating eddy currents and producing heat. The mold is located on the side of the base plate facing the heating cavity, and the mold's axis of symmetry, the axis of the central rod, and the power output shaft of the rotating drive coincide. The temperature measuring assembly is located in the furnace body and is used to measure the temperature inside the heating cavity.

[0007] Based on the above scheme, the furnace body can be equipped with an air inlet to introduce inert gas; the mold and the base plate can be detachably connected by connecting hole groups and bolts; the preparation device can also include a straightening component to limit the tilting of quartz raw materials; the preparation device can also include a lifting component to realize the up and down movement of the rotating component; the base plate can be equipped with a central hole to achieve a reliable positioning connection with the central rod; the temperature measuring component can adopt a thermocouple temperature measuring device, etc.

[0008] Secondly, this application provides a method for preparing a quartz ring, which uses the above-mentioned preparation device to induction heat and rotate a quartz raw material with a central hole to form a cylindrical quartz product and then cut it to obtain a quartz ring.

[0009] Compared with existing technologies, this application achieves direct forming of quartz rings by setting a rotatable base plate and coaxial mold and center rod, and using induction heating to make the heating element heat up evenly during rotation. This reduces material waste in traditional hole-punching processes and significantly improves material utilization. At the same time, uniform heating and rotation promote the densification of quartz material melting, reduce bubbles and inclusion defects, and improve forming consistency and dimensional accuracy. In addition, the movable design of the base plate facilitates mold maintenance and replacement, which helps to enhance the applicability of the equipment and reduce the overall preparation cost while ensuring high-purity, low-defect products. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the quartz ring preparation apparatus provided in the embodiments of this application.

[0011] Figure 2 This is a schematic flowchart illustrating the preparation method of the quartz ring provided in the embodiments of this application.

[0012] Explanation of main component symbols 100: Apparatus for preparing quartz rings; 10: Furnace body; 11: Side wall; 12: Top plate; 13: Heating chamber; 14: Opening; 15: Air inlet; 20: Rotating component; 21: Rotating drive component; 22: Base plate; 23: Center rod; 30: Heating component; 31: Coil; 32: Heating element; 40: Mold; 50: Temperature sensing component; 60: Corrective documents; 70: Lifting assembly. Detailed Implementation

[0013] The technical solution of this application will be further described below with reference to the accompanying drawings. It should be noted that the embodiments described in this application are only used to explain this application and are not intended to limit this application; those skilled in the art can make equivalent substitutions or appropriate modifications to the structural form, connection method, material selection, process parameters, etc. without departing from the spirit of this application, and all such modifications should fall within the protection scope of this application.

[0014] This application proposes a fabrication method for quartz rings commonly used in semiconductor etching processes (e.g., insulation, support, or gas rectification components for plasma etching cavities) using a "high-temperature sink forming + rotary centrifugal shaping" approach. Compared to the traditional "quartz ingot hollowing ring forming" method, this application reduces the large amount of excess material in the inner and outer rings caused by size variations. Compared to "synthetic quartz sand melting ring forming / pressing into cylinders," this application eliminates the need for first preparing costly synthetic quartz sand or undergoing high-pressure pressing, thus reducing raw material and equipment costs and improving issues such as difficult demolding and insufficient cylinder life.

[0015] This method uses a quartz raw material with a central hole (preferably a cylindrical quartz glass raw material or a pre-made quartz cylindrical blank) as the starting material. Quartz exhibits high-viscosity flow characteristics near its softening temperature (typically around 1500°C, depending on purity, atmosphere, and viscosity characteristics). When the blank rotates around its axis of symmetry in a softened state, under the combined action of centrifugal force and gravity, the softened quartz tends to spread outward and downward, undergoing a "groove" deformation: its outer side gradually approaches and adheres to the inner wall of the mold, while the inner side remains concentric under the constraint of the central rod and its own viscosity, thus obtaining a cylindrical quartz product with an outer diameter limited by the mold, high concentricity, and controllable wall thickness distribution. After cooling and demolding, the cylindrical quartz product can be processed into quartz rings of different specifications through fine grinding and slitting of the inner and outer circles.

[0016] Please see Figure 1This application provides an embodiment of a quartz ring preparation apparatus 100 (hereinafter referred to as preparation apparatus 100). The preparation apparatus 100 includes a furnace body 10, a rotating assembly 20, a heating assembly 30, a mold 40, and a temperature measuring assembly 50. The components are structurally coordinated to enable heating, rotation, limiting and shaping, atmosphere control, and temperature monitoring to be realized in the same set of equipment, thereby improving the stability and consistency of the forming process.

[0017] The furnace body 10 is generally box-shaped, with side walls 11 and a top plate 12. The side walls 11 and the top plate 12 enclose a heating cavity 13. An opening 14 is provided at the end of the furnace body 10 away from the top plate 12, connecting the heating cavity 13 to the external environment. Preferably, the axis of the heating cavity 13 is vertical or approximately vertical to facilitate downward spreading under gravity during the sinking process. The furnace body 10 can be constructed of non-metallic high-temperature resistant materials for load-bearing and heat insulation, such as high-purity alumina, mullite, corundum refractory materials, or aluminosilicate fiber composite structures. To effectively couple the alternating magnetic field generated by the outer coil to the heating element within the heating cavity 13, the side walls 11 of the furnace body 10 are preferably made of non-conductive material, at least in the corresponding coil region, to reduce magnetic field shielding or ineffective eddy current heating generated on the side walls 11.

[0018] The furnace body 10 may further include a heat insulation layer and a heat insulation layer, such as multi-layer refractory fiber felt or microporous heat insulation board on the outer side of the side wall 11 and the top plate 12, to reduce the temperature rise of the outer wall and reduce heat loss. The top plate 12 may be designed as a detachable structure to facilitate maintenance, repair or replacement of the temperature measuring component 50. It may also be designed as a fixed structure, which can be installed and removed through the inspection port of the side wall 11 or the opening 14. The opening 14 area of ​​the furnace body 10 may be provided with a high-temperature resistant sealing structure or a labyrinth gap structure, so that when the rotating component 20 passes through the opening 14, it can maintain the necessary ventilation and exhaust channels, and reduce the disturbance of external cold air to the heating chamber 13, thereby improving the temperature field stability.

[0019] The rotating assembly 20 rotatably passes through the opening 14 of the furnace body 10. The rotating assembly 20 includes a rotating drive component 21, a base plate 22, and a central rod 23. The rotating drive component 21 is connected to the base plate 22, which movably passes through the opening 14. The central rod 23 is located on the side of the base plate 22 facing the heating chamber 13, and the rotating drive component 21 drives the base plate 22 to rotate. The rotating drive component 21 can be a servo motor, a frequency converter motor, or a direct-drive torque motor, and is coaxially connected to the base plate 22 via a coupling or drive shaft, thereby ensuring smooth rotation and controllable speed. Preferably, the rotating drive component 21 has closed-loop speed control capability to achieve a speed curve of "low-speed start-up—gradual acceleration—constant speed forming—gradual deceleration," reducing the risk of eccentricity, rolling, or local collapse of softened quartz under transient conditions.

[0020] The base plate 22 serves as a load-bearing component, on which the mold 40, heating element 32, and center rod 23 can be mounted, and it bears the weight of the high-temperature components and the rotational centrifugal load. The base plate 22 can be made of a high-temperature resistant metal or non-metal composite structure, such as a heat-resistant alloy skeleton + ceramic insulation layer, or a water-cooled structure to reduce the temperature rise at the connection with the rotating drive component 21. An annular gap S can be left between the base plate 22 and the opening 14 of the furnace body 10, which is used for assembly tolerance and thermal expansion compensation, and can also serve as a gas exhaust channel, allowing inert gas to enter from the top, flow downward along the heating chamber 13, and exit from the gap S in the opening 14, realizing a "top-in, bottom-out" atmosphere replacement path.

[0021] The center rod 23 provides positioning and coaxial reference for the quartz raw material with a central hole. The axis of the center rod 23 preferably coincides with the power output shaft of the rotary drive 21. The center rod 23 can be a one-piece structure or a replaceable structure to accommodate quartz raw materials with different inner diameter ranges or target quartz ring sizes. The material of the center rod 23 can be alumina ceramic, silicon nitride ceramic, or high-purity graphite, etc., which are high-temperature resistant and low-pollution materials. To reduce adhesion between softened quartz and the center rod 23, an isolation layer or coating can be provided on the surface of the center rod 23, such as high-purity graphite paper, boron nitride coating, or high-purity ceramic coating; the isolation layer should meet the requirements of not being easily volatilized, not easily detached, and not introducing migratable impurities at operating temperatures.

[0022] The heating assembly 30 includes a coil 31 and a heating element 32. The coil 31 is disposed on the outer side of the side wall 11 of the furnace body 10 away from the heating cavity 13, and the heating element 32 is disposed on the side of the bottom plate 22 facing the heating cavity 13. After an alternating current is applied to the coil 31, an alternating magnetic field is generated. The magnetic field passes through the side wall 11 of the furnace body 10 and couples to the heating element 32 inside the heating cavity 13, causing eddy currents to form inside the heating element 32 and generating heat. Since quartz material has extremely low electrical conductivity and is difficult to heat directly through induction heating, this application uses the heating element 32 as an "induction heating element / radiation heat source" to heat the quartz raw material through radiation, convection, and a certain heat conduction (that is, after the heating element heats the mold through thermal radiation, the inner wall of the mold performs secondary thermal radiation on the quartz raw material, which is combined with heat conduction and convection heat transfer in the heating cavity to achieve heating), realizing a rapid, clean, and controllable heating process.

[0023] The coil 31 can be wound with water-cooled copper tubing. The number of turns, wire diameter, coil height, and coil position can be designed according to the target temperature zone and the geometry of the heating element 32. The coil 31 can be further connected to a medium-frequency or high-frequency induction power supply to adjust the output power and frequency, balancing heating efficiency and temperature field uniformity. To improve safety and stability, an insulating shield and a cooling water flow monitoring device can be installed on the outside of the coil 31 to reduce the risk of overheating or water leakage.

[0024] The heating element 32 is a ring-shaped or cylindrical component made of conductive and high-temperature resistant material, with its axis coaxial with the axis of the central rod 23 to form a symmetrical radiative heat field. The heating element 32 can be made of high-purity graphite, silicon carbide, molybdenum, tungsten, or heat-resistant alloys, etc.; among which, high-purity graphite has good induction heating response and thermal radiation capability, but it is easily oxidized in an oxygen-containing atmosphere, therefore it is preferred to use it in an inert gas atmosphere, or to apply an anti-oxidation coating (such as a silicon carbide coating or an oxide coating) to its surface. A certain distance can be maintained between the heating element 32 and the mold 40 to reduce deformation caused by the superposition of thermal stress; a ring-shaped heating gap can also be maintained between the heating element 32 and the quartz raw material to achieve "circumferential encirclement" uniform heating, reducing the risk of sagging, blistering, or crystallization caused by local overheating.

[0025] The mold 40 is located on the side of the base plate 22 facing the heating chamber 13. The mold 40 is used to limit and shape the softened quartz during the sinking process, and its inner wall dimensions correspond to the outer diameter or shape of the target cylindrical quartz product. The axis of symmetry of the mold 40 coincides with the axis of the central rod 23 and the power output shaft of the rotary drive component 21, thereby maintaining coaxiality and roundness during rotational forming. The mold 40 can be a cylindrical mold 40, a ring mold 40, or a combined mold 40 with a stepped structure, and can be specifically designed according to the target height, wall thickness distribution, and end face shape of the quartz ring.

[0026] The mold 40 may be provided with a first set of connecting holes (not shown), and the base plate 22 may be provided with a second set of connecting holes (not shown) corresponding to the first set of connecting holes. The first set of connecting holes and the second set of connecting holes are connected by bolts. Preferably, the connecting holes are distributed at equal angles along the circumference of the mold 40 to prevent the mold 40 from becoming misaligned after installation. The bolts may be high-temperature alloy bolts and may be used with elastic washers or ceramic gaskets to compensate for differences in thermal expansion. A heat insulation pad may be provided between the mold 40 and the base plate 22 to reduce heat transfer to the base plate 22 and reduce thermal deformation of the base plate 22.

[0027] The mold 40 is made of a material that is resistant to high temperatures, low in pollution, and has good thermal shock stability, such as high-purity graphite, carbon-carbon composite materials, silicon carbide ceramics, or high-purity alumina ceramics. Considering that quartz parts used for semiconductor etching are extremely sensitive to metallic impurities, the mold 40 material preferably avoids migratable metal elements; for graphite molds 40, the risk of carbon pollution can be reduced by selecting high-purity graphite and using a dense surface coating and an insulating liner. In some embodiments, an insulating material, such as perforated high-purity graphite paper or a boron nitride coating, can be laid on the inner wall of the mold 40 and the surface of the base plate 22 to prevent adhesion caused by direct contact between the high-temperature softened quartz and the mold 40, and also to facilitate demolding.

[0028] A temperature measuring component 50 is installed in the furnace body 10 to measure the temperature inside the heating chamber 13. The temperature measuring component 50 may include a thermocouple thermometer, and may employ high-temperature precious metal thermocouples or tungsten-rhenium thermocouples to meet temperature measurement requirements above 1500℃. The temperature measuring component 50 can be inserted into the heating chamber 13 from the side wall 11 or top plate 12 of the furnace body 10 and is isolated and protected by a protective sleeve; the protective sleeve may be made of high-purity quartz, alumina, or silicon carbide to prevent the thermocouple from being directly exposed to high-temperature radiation and corrosive environments. The position of the temperature measuring component 50 can be selected close to the heating element 32 or close to the typical temperature zone of the quartz raw material to more accurately reflect the forming process temperature; multiple temperature measurement points can also be set to monitor the temperature gradient and improve temperature control accuracy.

[0029] To control the atmosphere and protect high-temperature components, the furnace body 10 may be equipped with an air inlet 15 near the top plate 12. The air inlet 15 is connected to the heating chamber 13 and is used to introduce an inert gas, such as nitrogen, argon, or helium, into the heating chamber 13. The inert gas can reduce oxidation losses of the heating element 32 or the mold 40 (especially graphite materials), extending their lifespan. Furthermore, it can suppress the effects of water vapor and oxygen in the air on the quartz surface, reducing high-temperature volatilization or surface defects, and helping to expel adsorbed gases released during the heating stage, reducing the risk of bubbles. The air inlet 15 can be used with a mass flow controller to achieve a stable flow rate; it can also be used with a tail gas emission or extraction system to achieve micro-positive or micro-negative pressure control within the heating chamber 13.

[0030] In some embodiments, the preparation apparatus 100 further includes a straightening member 60. The straightening member 60 is disposed at the end of the mold 40 away from the base plate 22 and extends toward the central rod 23. It is used to guide or limit the upper end of the quartz raw material before and during forming, preventing the cylindrical quartz raw material from tipping over unilaterally due to thermal stress or its own weight before softening. The straightening member 60 may be an annular support structure with a groove that mates with the outer circle or end face of the upper end of the quartz raw material; the straightening member 60 may also be a plurality of evenly distributed limiting blocks or roller structures, providing circumferential limiting without significantly obstructing heat radiation. The straightening member 60 is preferably made of a high-temperature resistant, low-pollution material, such as high-purity quartz, alumina ceramic, or high-purity graphite with a protective coating.

[0031] In some embodiments, the preparation apparatus 100 further includes a lifting assembly 70, which is connected to the rotating assembly 20 to move the rotating assembly 20 closer to or further away from the furnace body 10. The lifting assembly 70 may include a lifting motor, a lead screw mechanism, guide columns, and sliders, etc., to allow the base plate 22 to move smoothly between the loading / unloading position and the heating working position. The advantages of using the lifting assembly 70 are: firstly, loading and demolding can be completed outside or below the furnace body 10, providing more operating space; secondly, the working position can be repeatedly positioned to ensure that the height of the billet relative to the coil 31 and the heating element 32 is consistent in each batch, thereby improving temperature field consistency and forming repeatability. The lifting assembly 70 can also be integrated with the rotating drive component 21 to form an integrated "rotation + lifting" platform, reducing coaxial errors and assembly complexity.

[0032] Please see Figure 1 and Figure 2 This application also provides a method for preparing a quartz ring. The method includes at least the following steps, and each step can be appropriately adjusted according to the equipment scale and product specifications: S1: Raw material preparation and cleaning, specifically: Provide quartz raw materials with a central hole. The quartz raw materials can be cylindrical quartz glass raw materials, precast quartz blanks, or hollow quartz precast parts obtained through other processes. To improve the cleanliness and consistency of the subsequent finished products, it is preferable to clean the quartz raw materials before loading into the furnace, such as by rinsing with ultrapure water, acid washing and deionization (e.g., external surface treatment with a combination of dilute hydrofluoric acid / dilute hydrochloric acid, the specific choice depending on process safety and material requirements), ultrasonic cleaning, and drying, and ensure that the end face of the raw materials is flat, parallel, and perpendicular to the side wall 11, so as to reduce eccentric vibration and local stress concentration during rotation.

[0033] S2: Loading and alignment, specifically: When the rotating assembly 20 is in the loading position away from the furnace body 10, the quartz raw material with a central hole is placed on the central rod 23, with its lower end face in contact with the base plate 22 or supported by an isolation gasket. Then, the mold 40 is installed on the base plate 22 and fixed thereto by connecting holes and bolts, ensuring that the axis of symmetry of the mold 40 coincides with the axis of the central rod 23. If necessary, an isolation layer is laid on the inner wall of the mold 40 and the surface of the base plate 22 to reduce adhesion and facilitate demolding. The heating element 32 is then installed on the side of the base plate 22 facing the heating chamber 13, and its spatial position corresponds to that of the coil 31 to achieve higher inductive coupling efficiency. If the preparation apparatus 100 includes a straightener 60, the straightener 60 is installed at the end of the mold 40 away from the base plate 22, extending towards the central rod 23 and limiting the upper end of the quartz raw material, thereby reducing the risk of tipping during the forming process.

[0034] During the loading process, coaxiality should be carefully controlled: the axis of the center rod 23, the power output shaft of the rotary drive component 21, and the axis of symmetry of the mold 40 should be as coincident as possible; if there is a deviation, it may be amplified into uneven wall thickness or overall eccentricity under high temperature softening and high speed rotation conditions. Therefore, the connection between the center rod 23 and the base plate 22 should adopt a reliable positioning structure, such as a center hole in the base plate 22 through which the center rod 23 passes and is fixedly connected to the base plate 22, with end face positioning and threaded locking to prevent the center rod 23 from loosening during thermal cycling.

[0035] S3: The heating chamber 13 is raised and the temperature is increased, specifically: After loading, the rotating component 20 is brought closer to the furnace body 10 and enters the working position, so that the quartz raw material, mold 40 and heating element 32 are located in the heating chamber 13. If the device includes a lifting component 70, the rotating component 20 can be raised to the working position by the lifting component 70; in some implementations, the working position can be set so that the bottom plate 22 is basically flush with the lower edge of the opening 14 of the furnace body 10 or maintains a preset gap S, so as to take into account both atmosphere flow and thermal stability.

[0036] Subsequently, coil 31 is energized, generating an alternating magnetic field that induces eddy currents in heating element 32, causing heating element 32 to heat up. Heating element 32 heats the quartz raw material through radiation, convection, and a certain amount of heat conduction, gradually raising the temperature of the quartz raw material. In the initial stage of heating, a faster heating rate (e.g., 5–20 °C / min) is preferably used to raise the heating chamber 13 to the medium-low temperature range to shorten the process cycle. When the temperature approaches the range where the viscosity of the quartz decreases significantly, the heating rate can be reduced (e.g., 1–30 °C / h) to improve temperature control accuracy and reduce thermal stress cracking caused by excessive temperature difference.

[0037] S4: Inert atmosphere replacement, specifically: In some embodiments, when the temperature sensing component 50 detects that the temperature of the heating chamber 13 has risen to a preset temperature threshold (e.g., approximately 200°C), inert gas is introduced into the heating chamber 13 through the air inlet 15. The flow rate of the inert gas can be set according to the volume of the furnace body 10 and the exhaust conditions, for example, 10 to 100 standard liters per minute. Introducing inert gas can replace the heating chamber 13, reduce the oxygen content, and remove water vapor, adsorbed gases, and trace volatiles released during the heating stage, thereby reducing bubble defects and protecting graphite components. The inert gas can be continuously introduced throughout the high-temperature forming stage, or the flow rate can be gradually reduced or stopped during the cooling stage after forming is completed.

[0038] S5: Rotational forming and slotting, specifically: When the temperature of the heating chamber 13 rises to near the softening temperature of the quartz raw material (e.g., 1450–1550°C), the rotary drive 21 is activated, causing the base plate 22 to rotate the quartz raw material around the axis of the central rod 23. A lower rotation speed (e.g., 10–100 rpm) is preferable during the initial rotational start-up phase to allow the quartz raw material to achieve centering and stable rotation before it is fully softened. Subsequently, as the temperature further increases and enters the forming window (e.g., 1600–1750°C), the rotation speed is gradually increased to the forming speed (e.g., 200–800 rpm). Under centrifugal force, the softened quartz raw material gradually spreads outwards and downwards, and sinks. When its outer side contacts the inner wall of the mold 40, the mold 40 provides a limit on its outer diameter. Under continuous rotation and heat preservation conditions, the quartz raw material completes its shape shaping and wall thickness homogenization. The forming and heat preservation time can be set according to the blank quality, target wall thickness, and temperature, for example, 10–60 minutes. During the heat preservation process, a constant rotation speed can be maintained, or the rotation speed can be finely adjusted according to observation or feedback to make the wall thickness distribution more in line with the target requirements.

[0039] It should be noted that the rotation curve has a significant impact on the forming quality: if there is no rotation or the rotation speed is too low, the softened quartz will sag under the influence of gravity, which can easily lead to internal folding, local accumulation, or air bubble entrainment; if a high rotation speed is suddenly started before the quartz has softened sufficiently, the quartz raw material may wobble due to unbalanced load, or even cause eccentricity due to one side contacting the mold 40 first. By using a strategy of "low-speed start + gradual acceleration", and with the upper limit of the straightening component 60, eccentricity and wall thickness difference can be significantly reduced.

[0040] S6: Cooling, annealing, and unloading, specifically: After forming is complete, the coil 31 is energized or the induction power is reduced, causing the heating element 32 to stop heating and enter the cooling stage. To reduce thermal stress and cracking risk, controlled cooling can be used in the high-temperature zone (e.g., reducing from 1-30°C / h to approximately 1200°C), and the forming speed is maintained or appropriately reduced during cooling to keep the quartz, which is still in a high-viscosity state, round and reduce new deformation caused by its own weight. When the temperature is further reduced to a lower temperature zone (e.g., below 1200°C), natural cooling can be used. As the temperature decreases, the rotation speed is gradually reduced and eventually stopped to reduce inertial impact or residual deformation caused by stopping too quickly.

[0041] When the temperature measuring component 50 detects that the temperature of the heating chamber 13 has dropped to a preset unloading temperature threshold (e.g., approximately 200°C), the rotating component 20 is moved away from the furnace body 10 and returns to the loading / unloading position. If the device includes a lifting component 70, the rotating component 20 can be lowered to the lower limit position via the lifting component 70. After the cylindrical quartz product has completely cooled, the straightening component 60 and the mold 40 are removed, and the demolding operation is performed to obtain the cylindrical quartz blank. During demolding, an isolation layer can be used to reduce adhesion. If necessary, slight mechanical vibration or uniform ejection can be used to reduce the introduction of microcracks by localized impacts.

[0042] S7: Post-processing ring making, specifically: After obtaining the cylindrical quartz blank, its inner and outer diameters can be precision-machined by internal and external grinding to improve roundness and concentricity. Then, it is slit to the required thickness to obtain quartz rings. Slitting can be done using diamond wire cutting, internal or external cutting, combined with coolant to control thermal cracking. After processing, it can be cleaned, acid-washed to remove contaminants, and dried to meet the stringent requirements of the semiconductor industry regarding particle, metal ion, and carbon contamination.

[0043] To further illustrate the feasibility and effectiveness of the proposed solution, several embodiments and comparative examples are provided below. It should be noted that the parameters below are merely examples and do not constitute a limitation on the scope of protection of this application.

[0044] Example 1 When the lifting assembly 70 is at its lower limit, a cylindrical quartz material with an outer diameter of approximately 300 mm, an inner diameter of approximately 100 mm, and a height of approximately 500 mm is placed at the center of the base plate 22. The cylindrical quartz material is wire-cut to ensure that the upper and lower end faces are flat, parallel, and substantially perpendicular to the side wall 11. The center hole of the cylindrical quartz material is fitted onto the center rod 23, which has a diameter of approximately 80 mm and a height of approximately 550 mm, and is fixed to the base plate 22 via a bottom connecting structure. Subsequently, the mold 40 is fixed to the base plate 22. The lower end of the mold 40 has a first set of equally spaced connecting holes, which are aligned with the corresponding second set of connecting holes on the base plate 22 and then fixed with bolts. The inner wall diameter of the mold 40 is approximately 402 mm, and the height is approximately 400 mm. A perforated high-purity graphite paper is laid between the inner wall of the mold 40 and the surface of the base plate 22 as an isolation layer. After fixing the mold 40, a straightener 60 is installed on the upper end of the mold 40. The straightener 60 is positioned by a slot and fixed by bolts to limit the swinging of the upper end of the cylindrical quartz raw material. The annular heating element 32 is placed outside the mold 40 and maintained at a preset distance from it. The temperature measuring component 50 is a fixed-position thermocouple thermometer used to detect the temperature of the heating chamber 13.

[0045] After loading, the rotating assembly 20 is raised to the working position by the lifting assembly 70, so that the bottom plate 22 is basically flush with the lower edge of the opening 14 of the furnace body 10, and an annular gap for gas flow is maintained between the bottom plate 22 and the furnace body 10. Then, the coil 31 is energized, and the heating element 32 induced heat and began to heat up. After heating to approximately 200°C at a rate of approximately 10°C / min, nitrogen gas is continuously introduced into the heating chamber 13 through the air inlet 15 at a flow rate of approximately 50 standard liters / min. When the furnace temperature reaches approximately 1500°C, the rotating drive 21 is activated and the initial speed is set to approximately 50 rpm; subsequently, the temperature is increased to approximately 1650°C at a rate of approximately 10°C / h, during which the speed is gradually increased to approximately 500 rpm. After holding at approximately 1650°C for approximately 30 minutes, the temperature is decreased to approximately 1200°C at a rate of approximately 10°C / h, during which the speed is maintained at approximately 500 rpm. Below 1200℃, natural cooling is used, with the rotation speed gradually reduced to 0 at a rate of approximately 5 rpm per minute. After cooling to approximately 200℃, the rotating component 20 is lowered to its lower limit using the lifting component 70. Once the cylindrical quartz product has completely cooled, it is demolded to obtain a cylindrical quartz blank with an outer diameter of approximately 400 mm, an inner diameter of approximately 200 mm, and a height of approximately 330 mm. This cylindrical quartz blank is then processed and slit to produce quartz rings, achieving a comprehensive material utilization rate of over 60%.

[0046] Example 2 Except for the following differences, the process is basically the same as in Example 1: the height of mold 40 is approximately 350 mm; the rotary drive 21 is started when the temperature is raised to approximately 1500°C, with an initial rotation speed of approximately 50 rpm, and then the rotation speed is gradually increased to approximately 300 rpm during the process of raising the temperature to approximately 1650°C; the rotation speed is maintained at approximately 500 rpm during the process of cooling to approximately 1200°C. After demolding, a cylindrical quartz blank with an outer diameter of approximately 400 mm, an inner diameter of approximately 180 mm, and a height of approximately 313 mm is obtained. It can be seen that by adjusting the rotation speed curve during the forming stage, the inner diameter and wall thickness distribution of the cylindrical quartz blank can be changed, thereby adapting to the processing requirements of quartz rings of different specifications.

[0047] Example 3 Except for the following differences, the process is basically the same as in Example 1: the rotary drive 21 is started when the temperature is raised to about 1500°C, with an initial rotation speed of about 50 rpm; the rotation speed is gradually increased to about 700 rpm during the process of raising the temperature to about 1650°C; and the rotation speed is maintained at about 500 rpm during the process of cooling to about 1200°C. After demolding, a cylindrical quartz blank with an outer diameter of about 400 mm, an inner diameter of about 245 mm, and a height of about 400 mm is obtained. The results show that increasing the peak rotation speed during the forming stage within a certain range is beneficial to increasing the degree of outward spreading of the inner side under the action of centrifugal force, thereby increasing the inner diameter; however, excessively high rotation speed may increase the risk of vibration and eccentricity, so it is advisable to combine the centering component 60 with the centering accuracy in a comprehensive design.

[0048] Comparative Example 1 Compared to Example 1, in Comparative Example 1, the rotating drive 21 was not activated during the entire heating, holding, and cooling process, meaning the quartz raw material did not rotate. Other process conditions were the same as in Example 1. After demolding, a cylindrical quartz product with an outer diameter of approximately 400 mm, an inner diameter of approximately 80 mm, and a height of approximately 260 mm was obtained. However, it exhibited obvious folding, accumulation, and bubble defects internally, resulting in a yield of less than 40% during subsequent ring-making. This comparative example illustrates that relying solely on gravity sinking without the combined effect of rotational centrifugal force is insufficient to obtain a cylindrical quartz blank with uniform wall thickness and fewer defects.

[0049] Comparative Example 2 Compared to Example 1, Comparative Example 2 started the rotating drive 21 at a temperature of approximately 1500°C in the heating chamber 13 and directly set the rotation speed to approximately 500 rpm, without employing a gradual acceleration strategy. Other process conditions were the same as in Example 1. After demolding following the sinking process, it was found that the cylindrical quartz product was concentrated to one side, resulting in significant differences in wall thickness at different circumferential positions, making it difficult to process into a quartz ring that met the concentricity requirements. This comparative example illustrates that sudden high-speed rotation before the quartz raw material has fully softened or the system is not stably aligned can easily induce eccentricity and uneven wall thickness; using a low-speed start-up and gradually accelerating rotation speed curve can significantly improve forming stability.

[0050] Through the above structure and method, this application has at least the following technical effects: First, by using the mold 40 and the central rod 23 for coaxial positioning and cooperating with the rotary centrifugal sink forming, the roundness, concentricity and wall thickness uniformity of the cylindrical quartz blank can be significantly improved, reducing subsequent machining allowance; Second, by directly forming the cylindrical quartz blank from the quartz raw material with a central hole and cutting it into rings, the material utilization rate can be significantly improved, and the excess material in the inner and outer rings caused by the hole-making rings can be reduced; Third, by using an induction heating structure with the coil 31 outside the furnace body 10 and the heating element 32 inside the heating chamber 13, the electrical components can be kept away from the high-temperature pollution environment, improving maintenance convenience and achieving rapid and controllable heating; Fourth, by introducing inert gas through the air inlet 15, the heating element 32 and the mold 40 can be protected and defects reduced, adapting to the cleanliness and consistency requirements of semiconductor-grade quartz parts.

[0051] Without departing from the scope of the claims of this application, various extensions are possible: for example, infrared thermometry or multi-point thermocouples can be added to the temperature measuring component 50 to achieve zoned temperature control; the mold 40 can be designed with a replaceable bushing structure to quickly switch between different outer diameter specifications; an adjustable counterweight structure can be set on the base plate 22 to further reduce high-speed rotational vibration; the inert gas can be linked with the exhaust system to achieve a lower oxygen content atmosphere; a reflective screen or heat insulation screen can also be added to the heating element 32 to improve thermal efficiency and reduce axial temperature difference. All the above modifications and improvements should be considered to fall within the protection scope of this application.

Claims

1. An apparatus for preparing quartz rings, characterized in that, include: The furnace body has side walls and a top plate, the side walls and the top plate forming a heating cavity, and the furnace body has an opening away from the top plate, the opening connecting the heating cavity to the external environment; A rotating assembly rotatably passes through the opening. The rotating assembly includes a rotating drive, a base plate, and a central rod. The rotating drive is connected to the base plate, and the base plate movably passes through the opening. The central rod is located on the side of the base plate facing the heating cavity. The rotating drive is used to drive the base plate to rotate. A heating assembly, comprising a coil and a heating element, wherein the coil is disposed on the outer side of the side wall away from the heating cavity, and the heating element is disposed on the side of the base plate facing the heating cavity, and the heating element is used to sense the alternating current in the coil, thereby forming eddy currents and generating heat; The mold is located on the side of the base plate facing the heating cavity. The mold is located inside the heating body and maintains a distance from the heating body. The axis of symmetry of the mold, the axis of the central rod, and the power output shaft of the rotary drive coincide. A straightening component is provided at the end of the mold away from the base plate, and the straightening component extends toward the center rod; A temperature measuring component is disposed in the furnace body and is used to measure the temperature inside the heating chamber.

2. The preparation apparatus according to claim 1, characterized in that, The furnace body has an air inlet near the top plate, which is connected to the heating chamber and is used to introduce inert gas into the heating chamber.

3. The preparation apparatus according to claim 1, characterized in that, The mold is provided with a first set of connecting holes, and the base plate is provided with a second set of connecting holes corresponding to the first set of connecting holes. The first set of connecting holes and the second set of connecting holes are connected by bolts.

4. The preparation apparatus according to claim 1, characterized in that, The preparation apparatus further includes a lifting assembly connected to the rotating assembly, which drives the rotating assembly to move closer to or further away from the furnace body.

5. The preparation apparatus according to claim 1, characterized in that, The base plate has a central hole, and the central rod passes through the central hole and is fixedly connected to the base plate.

6. The preparation apparatus according to claim 1, characterized in that, The temperature measuring component includes a thermocouple temperature sensor.

7. A method for preparing a quartz ring, characterized in that, Includes the following steps: An apparatus for preparing a quartz ring as described in any one of claims 1 to 6 is provided; A quartz raw material with a central hole is fitted onto the central rod, and the quartz raw material is positioned inside the mold. Adjust the position of the rotating component relative to the furnace body so that the quartz raw material is in the working position inside the heating chamber; The coil is energized to raise the temperature of the heating element, which in turn heats the quartz raw material. After the quartz raw material reaches the softening temperature, the rotary drive component drives the base plate to rotate, thereby causing the quartz raw material to rotate around the axis of the central rod. Under the action of centrifugal force and gravity, the quartz raw material sinks outward and downward into the groove and contacts the mold to form a cylindrical quartz product. The tubular quartz product is cooled and demolded to obtain a tubular quartz blank; The cylindrical quartz blank is machined and cut to obtain quartz rings.

8. The preparation method according to claim 7, characterized in that, The furnace body has an air inlet near the top plate, which is connected to the heating chamber. When the temperature measuring component detects that the temperature inside the heating chamber rises to a preset temperature threshold, inert gas is introduced into the heating chamber through the air inlet. The inert gas is continuously or intermittently introduced during the forming stage of the cylindrical quartz product.

9. The preparation method according to claim 7, characterized in that, The rotary drive starts at a first rotation speed and drives the quartz material to rotate after the quartz material reaches the softening temperature. During the heating or heat preservation process, the rotation speed is increased to a second rotation speed to complete the trough forming. During the cooling process, the rotation speed is reduced until it stops.

Images