A precision control on / off valve for semiconductor liquid circuits and its assembly method

Abstract

This invention relates to the field of fluid control devices in semiconductor fluid circuits, and proposes a precision control on / off valve for semiconductor fluid circuits and its assembly method. The valve includes a valve seat, a cylinder assembly attached to the valve seat, a diaphragm valve plate housed within the valve seat, and an adjusting wheel mounted on the cylinder cover. The cylinder assembly includes a cylinder cover and a cylinder body connected by a rotary locking structure, and internally assembles a piston assembly and a limiting rod assembly. The diaphragm valve plate is driven by the cylinder assembly to seal or disengage from the valve seat. The adjusting wheel is connected to the limiting rod assembly and is used to adjust the lifting and lowering of the limiting screw, thereby precisely limiting the maximum upward movement of the piston assembly and the valve opening. This invention overcomes the bottlenecks of easy wear and leakage in traditional mechanical valves, achieves precise flow adjustment, and significantly improves the long-term flow stability and the cleanliness and safety of ultrapure fluid systems.

Description

Technical Field

[0001] This invention relates to the field of fluid control devices in semiconductor liquid circuits (fluids such as photoresist, developer, organic solvents and other chemical media used in semiconductor processing), and in particular to a precision control on / off valve for semiconductor liquid circuits and its assembly method. Background Technology

[0002] The semiconductor manufacturing industry has developed rapidly in recent years. In semiconductor process equipment such as wet cleaning, electroplating, resist coating and development, and chemical mechanical polishing, the on / off and flow control of high-purity chemicals and electronic ultrapure water are crucial. These processes place extremely high demands on the precision, sealing, and corrosion resistance of fluid control, as even the slightest flow deviation or leakage can affect the quality and performance of semiconductor products. With the continuous advancement of semiconductor technology, the performance requirements for fluid control devices are also constantly increasing, and traditional control methods are gradually becoming insufficient to meet increasingly stringent production demands. In particular, as semiconductor manufacturing processes enter the sub-nanometer era, the sensitivity of wafer surfaces to metal ions and particles has increased exponentially. In wet cleaning and etching processes, even small fluctuations in the flow rate of the chemical solution (within ±1%) can lead to uneven etching rates, ultimately resulting in the scrapping of the entire wafer.

[0003] In the field of fluid control in semiconductor fluid circuits, conventional methods have been used to achieve valve on / off control and flow control. One common approach is to use ordinary valves, controlling fluid flow through simple on / off operations. However, this method struggles to achieve precise flow regulation and cannot meet the high-precision flow control requirements of semiconductor processes. Other methods utilize complex mechanical structures to control valve opening, but these structures are often bulky, incurring high installation and maintenance costs, and are prone to wear and failure during long-term use, affecting control stability and reliability. Furthermore, some traditional valves have insufficient sealing performance, leading to leakage and compromising the cleanliness and safety of the semiconductor fluid circuit. However, these existing technologies have significant drawbacks. Ordinary valves cannot precisely control flow, failing to meet the stringent flow accuracy requirements of semiconductor processes. Valves with complex mechanical structures are not only costly and difficult to maintain, but also prone to failure during long-term operation, resulting in unstable flow control. Simultaneously, the poor sealing performance of traditional valves easily causes fluid leakage, potentially contaminating the semiconductor fluid circuit, affecting the quality of semiconductor products, and even posing a threat to the production environment.

[0004] Utility model patent CN216200550U discloses a pneumatic aseptic shut-off valve, including a valve body with a cylinder mounted on it. The cylinder and valve body are connected by a clamp. A valve chamber is formed within the valve body, and a valve core is located within the valve chamber. The valve core has a diaphragm sealing plate that divides the valve chamber into an upper valve chamber and a lower valve chamber. The lower valve chamber communicates with a flow channel within the valve body. A pressure chamber is formed within the cylinder, and a valve stem extending into the upper valve chamber and connected to the valve core is slidably mounted within the pressure chamber. A piston located within the pressure chamber moves synchronously with the valve stem. A cylinder cover is located at the upper end of the cylinder, and a conversion cover is mounted on the cylinder cover. A compression spring is located between the cylinder cover and the piston to compress the piston downward. An air inlet is connected to the bottom of the pressure chamber. Although this solution achieves basic pneumatic isolation, it can only perform simple on / off operations and cannot meet the requirements of high-precision flow fine-tuning in semiconductor processes.

[0005] Chinese patent application CN102359648A discloses a large-diameter fast-exhaust slow-intake valve, comprising a valve body. The flow channel of the valve body is divided into an upper chamber C and a lower chamber D by a valve seat. A valve core is located above the valve seat. Its innovation lies in the inclusion of: a cylinder A located on the valve core's opening side, with its piston A connected to the valve core via a valve rod; and a cylinder B located on the valve core's closing side, with its piston B connected to a push rod extending into the valve body and facing the valve core. The chambers of cylinders A and B are connected to an air tank via solenoid valves. The lower chamber D of the valve body has an air hole connected to a two-position two-way valve. By utilizing the cooperation of cylinders A and B to drive the valve core to be close to or away from the valve seat, the valve body can be closed, opened to a small degree, or opened to a large degree, thereby achieving various working states of the cylinders in the air cushion device. This solution uses a complex combination of dual cylinders and solenoid valves to achieve opening control. This complex mechanical structure is not only bulky and has high installation and maintenance costs, but it is also prone to wear during long-term operation, leading to unstable flow control.

[0006] Utility model patent CN206398096U discloses a novel diaphragm valve, including a cylinder. The top of the cylinder is threadedly connected to a cylinder head, and the cylinder and cylinder head are sealed together by a cylinder head sealing ring. An adjusting rod passes through the cylinder head and is sealed to the cylinder head by a sealing ring. The cylinder head is connected to a piston via a resilient pin, and the piston and cylinder are sealed together by a piston sealing ring. A valve stem is located at the bottom of the piston, and the top of the valve stem extends into the interior of the piston and is sealed to the piston by a valve stem sealing ring. This design allows for adjustment of the piston stroke. However, under the long-term high-frequency pneumatic impact and pipeline vibration of semiconductor equipment, the traditional threaded adjustment structure is prone to loosening, causing the set flow point to drift. In addition, rigid impacts can easily generate microparticles and damage the thread precision, and the traditional valve cylinder body relies on bolt connections, resulting in low assembly efficiency and the risk of vibration-induced loosening. Summary of the Invention

[0007] The main objective of this invention is to provide a precision control valve for semiconductor fluid circuits. The main advancement lies in the fact that, through the integrated cylinder limiting structure and the diaphragm valve plate working together, it overcomes the bottleneck of traditional mechanical valves being prone to wear and leakage, achieving precise fine-tuning of flow rate, while significantly improving the flow stability during long-term operation and the cleanliness and safety of ultrapure fluid systems.

[0008] The second main objective of this invention is to provide an assembly method for a precision control on / off valve for semiconductor liquid circuits, wherein the assembled precision control on / off valve is applicable to semiconductor liquid circuits.

[0009] The main objective of this invention is achieved through the following technical solution: a precision control valve for semiconductor liquid circuits, comprising:

[0010] A valve seat, wherein the valve seat is provided with a valve port and a first flow channel and a second flow channel connecting the valve port;

[0011] A cylinder assembly, coupled to the valve seat, includes a cylinder body, a cylinder cover, and a piston assembly. The cylinder cover and the cylinder body are connected by a rotary locking structure. The piston assembly is assembled into the cylinder body. A limit rod assembly is connected inside the cylinder cover. The cylinder cover and the cylinder body provide space for the piston assembly and the limit rod assembly to move. The limit rod assembly includes an interconnected lead screw nut and a limit lead screw. The limit rod assembly is used to limit the maximum upward movement of the piston assembly to limit the valve opening.

[0012] A diaphragm valve plate, connected to the piston assembly and housed within the valve seat, the diaphragm valve plate having a centrally located valve core at the valve port, wherein the valve core is configured to be driven by the cylinder assembly to seal or disengage from the valve port;

[0013] An adjusting wheel, which is mounted on the cylinder cover and connected to the lead screw nut of the limiting rod assembly, is used to adjust the lifting and lowering of the limiting lead screw in the cylinder cover, so as to adjust the maximum upward position of the piston assembly and the valve core.

[0014] The implementation principle of this basic structure example is that the rotation of the adjusting wheel drives the limit rod assembly to change the axial height of the limit screw, thereby setting the physical limit point for the upward movement of the piston assembly. When the cylinder is vented, the piston drives the valve core of the diaphragm valve plate to disengage from the valve port and remain at the limit point, thus achieving a precise flow rate setting. Specific effects include:

[0015] 1) Achieve high-precision flow control. The screw drive of the adjusting wheel and the limit rod assembly allows for smooth and minute high-resolution adjustment of the piston's maximum stroke, meeting the stringent requirements of semiconductor processes for the accuracy of high-purity fluid flow.

[0016] 2) Improved cleanliness and leak-proof performance. The diaphragm valve is pneumatically driven to seal or open the valve port, avoiding frictional particles generated by traditional complex mechanical structures, effectively reducing the risk of leakage and ensuring the safety and cleanliness of the semiconductor liquid circuit.

[0017] 3) The system is highly integrated and stable. The cylinder cover and cylinder body directly provide the movement space for the piston and limit rod assembly. The compact structure reduces the overall center of gravity of the equipment and external interference, thereby improving the stability and reliability of valve opening and closing.

[0018] In a preferred embodiment, the present invention may be further configured such that: a top cover sealing ring is provided at the connection between the cylinder body and the cylinder top cover, the top cover sealing ring being used to seal the gap between the cylinder body and the cylinder top cover; the cylinder top cover has a top opening, and a rod assembly sleeve extending into the cylinder top cover is connected to the top opening; the rod assembly sleeve has a hollow inner cavity, the hollow inner cavity including an adjusting threaded section at the upper part and a sealing mating surface at the middle part; a lead screw nut is connected inside the rod assembly sleeve, wherein the upper part of the lead screw nut is associated with the adjusting threaded section, and the lower part of the lead screw nut is provided with a lead screw nut sealing ring, the lead screw nut sealing ring being used to seal the gap between the lead screw nut and the rod assembly sleeve; a limiting lead screw is connected to the lead screw nut inside the rod assembly sleeve, wherein the upper part of the limiting lead screw is associated with the lead screw nut, and the lower part of the limiting lead screw is provided with a limiting lead screw sealing ring, the limiting lead screw sealing ring being used to seal the gap between the limiting lead screw and the rod assembly sleeve.

[0019] By employing the optimized technical features of the aforementioned structure, a multi-layered dynamic and static leak-proof system is constructed. The sealing rings on the top cover, as well as the screw nut sealing rings and limiting screw sealing rings within the rod assembly sleeve, effectively prevent the driving gas in the pneumatic control chamber from leaking through the adjustment mechanism or connection gaps. This not only ensures the extremely high airtightness of the cylinder assembly but also maintains the stability of the pneumatic driving force, preventing gas leakage and contamination of the cleanroom environment.

[0020] In a preferred embodiment, the present invention may be further configured such that the hollow inner cavity of the rod sleeve includes a vertical limiting groove located at the lower part, and an anti-rotation pin located below the sealing ring of the limiting screw is provided at the lower part of the limiting screw. The anti-rotation pin cooperates with the vertical limiting groove to suppress the rotation of the limiting screw; wherein, the anti-rotation pin is a hollow cylindrical pin.

[0021] By employing the optimized technical features of the above structure, precise conversion of motion patterns is achieved. The engagement of the anti-rotation pin and the vertical limiting groove at the lower part of the rod sleeve completely restricts the circumferential rotation of the limiting screw following the screw nut, forcing it to move only axially in the vertical direction. This eliminates the torque damage to the internal sealing ring and piston caused by rotational friction, further ensuring the absolute accuracy of valve stroke adjustment.

[0022] In a preferred embodiment, the present invention may be further configured such that a stress relief groove is formed on the bottom surface of the limiting screw, the stress relief groove spans the diameter direction of the limiting screw, dividing the bottom surface of the limiting screw into two symmetrical pressure-bearing areas, and the bottom surface of the limiting screw is also covered with a buffer contact layer.

[0023] By employing the optimized technical features of the aforementioned structure, crucial rigid filtering and aerodynamic shock protection are provided. Upon piston impact, the buffer contact layer first undergoes elastic compression to dissipate kinetic energy and achieve a soft landing. Simultaneously, the stress relief groove, acting as a structural spring, generates a slight elastic bending, significantly weakening and smoothing out peak stress. This combination of rigid and soft buffering not only eliminates impact noise but also effectively isolates the transmission of shock waves to the precision threaded mechanism, ensuring the flow setpoint remains accurate even after millions of switching cycles, eliminating the need for frequent calibration.

[0024] In a preferred embodiment, the present invention may be further configured such that the piston assembly includes a piston body, an upper piston sealing ring, a lower piston sealing ring, and a spring; the piston body is provided with an upper sealing groove and a lower sealing groove, the upper piston sealing ring is disposed in the upper sealing groove, and the lower piston sealing ring is disposed in the lower sealing groove; the upper piston sealing ring and the lower piston sealing ring are used to seal the gap between the piston body and the cylinder body; the spring is mounted on the piston body and sleeved outside the rod assembly sleeve.

[0025] By adopting the optimized technical features of the above structure, the smoothness of piston movement and bidirectional pressure holding capability are enhanced. The double sealing design of the upper and lower piston sealing rings significantly improves the airtightness of the gap between the cylinder body and the piston body, preventing high-pressure gas leakage; the springs sleeved outside the rod sleeve are compactly arranged, providing the piston with a stable and reliable downward reset force, ensuring that the valve can close quickly and tightly when the gas source is cut off.

[0026] In a preferred embodiment, the present invention may be further configured such that the adjusting wheel includes a tensioning wheel and a handwheel sequentially disposed on the cylinder cover, both the handwheel and the tensioning wheel being associated with the lead screw nut, and the handwheel being equipped with a set screw; wherein the set screw is used to lock the handwheel and the lead screw nut, the handwheel is configured to drive the lead screw nut to rotate during the flow setting process, so as to move the limiting lead screw up and down, and the tensioning wheel is configured to abut against the handwheel after the flow setting process.

[0027] By employing the optimized technical features of the above structure, the problem of flow drift under high-frequency vibration in semiconductor equipment is completely solved. After the flow rate is set, the reverse rotation and tightening wheel are pressed tightly against the handwheel, creating a double-nut counteracting effect on the lead screw nut, which greatly amplifies the friction between the thread profiles. With the locking of the set screw, even under strong air hammer effects or external mechanical vibrations, the adjusted flow rate setpoint remains perfectly still, ensuring that the set flow rate accuracy does not drift over a long period.

[0028] In a preferred embodiment, the present invention may further include a base plate, which is mounted on the bottom of the valve seat. The base plate has a threaded hole, and the cylinder cover, the cylinder body, and the valve seat have through holes corresponding to the threaded hole of the base plate. A flat washer and a spring washer are installed at the through hole of the cylinder cover, and bolts are sequentially passed through the cylinder cover, the cylinder body, and the valve seat and locked to the threaded hole of the base plate.

[0029] By employing the preferred technical features of the above-mentioned structure, rapid centering and high-rigidity locking of the entire valve are achieved. The method of bolts sequentially penetrating the cylinder assembly and locking the valve seat to the base plate thread ensures that the valve seat and pneumatic actuator are subjected to uniform and consistent axial clamping force, avoiding microscopic deformation and leakage of the sealing surface caused by uneven local stress. Simultaneously, it greatly simplifies the disassembly and maintenance process of the equipment and improves the structural stability of the valve installed in complex semiconductor fluid circuits. The second main objective of this invention is achieved through the following technical solution: proposing an assembly method for a precision control on / off valve for semiconductor fluid circuits, including the following steps:

[0030] S1. A limit rod assembly is installed inside the cylinder cover, and an adjusting wheel is installed on the cylinder cover; wherein, the limit rod assembly includes an interconnected lead screw nut and a limit lead screw, and the adjusting wheel is connected to the lead screw nut of the limit rod assembly for adjusting the lifting and lowering of the limit lead screw in the cylinder cover;

[0031] S2. Install the piston assembly in the cylinder body;

[0032] S3. Combine the cylinder body and the cylinder top cover; wherein the cylinder top cover and the cylinder body are connected by a rotary locking structure, so that the cylinder top cover and the cylinder body provide the piston assembly and the limiting rod group with a space for movement, and the limiting rod group limits the maximum upward movement position of the piston assembly.

[0033] S4. Install the diaphragm valve plate at the lower end of the piston assembly;

[0034] S5. The valve seat is combined with the cylinder body and the cylinder cover; wherein the valve seat is provided with a valve port and a first flow channel and a second flow channel connecting the valve port, the diaphragm valve plate is housed in the valve seat, the diaphragm valve plate has a valve core located at the center, the valve core is located at the valve port, wherein the valve core is configured to be driven by the cylinder assembly to seal or disengage from the valve port.

[0035] This basic method example enables the efficient assembly of precision control on / off valves, ensuring the coaxiality and relative position of each precision component are accurate during assembly, and the sealing system is not damaged. The specific effects are as follows: the standardized top-down modular assembly process sequence greatly reduces the risk of seal damage and thread misalignment caused by blind operation, effectively improving the assembly efficiency of the production line and the factory qualification rate of finished valves.

[0036] In a preferred embodiment, the present invention can be further configured such that, in step S1, the cylinder upper cover has a top opening, and a rod sleeve extending into the cylinder upper cover is connected to the top opening. The rod sleeve has a hollow inner cavity, which includes an adjusting threaded section at the top and a sealing mating surface at the middle. The lead screw nut is connected to the rod sleeve, wherein the upper part of the lead screw nut is associated with the adjusting threaded section, and the lower part of the lead screw nut is provided with a lead screw nut sealing ring, which seals the gap between the lead screw nut and the rod sleeve. A limiting lead screw is connected to the lead screw nut within the rod sleeve, wherein the upper part of the limiting lead screw is associated with the lead screw nut, and the lower part of the limiting lead screw is provided with a limiting lead screw sealing ring, which seals the gap between the limiting lead screw and the rod sleeve. The hollow inner cavity also includes a vertical limiting groove located at the bottom. An anti-rotation pin is inserted through the lower part of the limiting screw, located below the limiting screw sealing ring. The anti-rotation pin cooperates with the vertical limiting groove to suppress rotation of the limiting screw. A stress relief groove is formed on the bottom surface of the limiting screw, spanning the diameter direction of the limiting screw and dividing the bottom surface of the limiting screw into two symmetrical pressure-bearing areas. The bottom surface of the limiting screw is also covered with a buffer contact layer. The adjusting wheel includes a tensioning wheel and a handwheel sequentially arranged on the cylinder cover. Both the handwheel and the tensioning wheel are associated with the screw nut. The handwheel is equipped with a set screw: the set screw is used to lock the handwheel and the screw nut. The handwheel is configured to drive the screw nut to rotate during flow setting, causing the limiting screw to move up and down. The tensioning wheel is configured to abut against the handwheel after the flow setting process.

[0037] By employing the optimized technical features of the above method, the modular solidification of the airtightness and precision transmission structure is completed in step S1. The limiting rod assembly, equipped with a sealing ring, anti-rotation pin, and stress-relief buffer structure, is precisely positioned within the rod assembly sleeve and locked using a double-coupling wheel structure. This pre-assembly process ensures the reference accuracy of the internal transmission shaft, laying a solid physical foundation for the subsequent valve to resist high-frequency pneumatic impacts, maintain extremely high airtightness, and prevent flow drift.

[0038] In a preferred embodiment, the present invention can be further configured such that, in step S2, the piston assembly includes a piston body, an upper piston sealing ring, a lower piston sealing ring, and a spring; the piston body is provided with an upper sealing groove and a lower sealing groove, the upper piston sealing ring is disposed in the upper sealing groove, and the lower piston sealing ring is disposed in the lower sealing groove; the upper piston sealing ring and the lower piston sealing ring are used to seal the gap between the piston body and the cylinder body; the spring is mounted on the piston body and sleeved outside the rod assembly sleeve; in step S5, a base plate is installed on the bottom of the valve seat, the base plate is provided with a base plate threaded hole, the cylinder cover, the cylinder body, and the valve seat are provided with through holes corresponding to the base plate threaded hole, a flat washer and a spring washer are installed at the through hole of the cylinder cover, and bolts are sequentially passed through the cylinder cover, the cylinder body, and the valve seat and locked to the base plate threaded hole of the base plate.

[0039] By employing the optimized technical features of the above method, excellent system-wide balanced pressing and fastening is achieved during the overall assembly stage. In step S2, the precise insertion of the piston and spring assembly ensures smooth, unobstructed movement of the moving parts. In step S5, through-bolts combined with flat washers and spring washers are used to lock the cylinder cover, cylinder body, valve seat, and base plate in series at once, ensuring highly consistent pressing force on all flange mating surfaces and internal diaphragms. This assembly method effectively counteracts the loosening risks caused by thermal expansion and contraction and system back pressure, greatly satisfying the stringent leak-proof requirements of semiconductor ultrapure fluid pipelines.

[0040] In summary, the technical solutions of the apparatus or method in this invention include at least one of the following technical effects that contribute to the prior art:

[0041] 1. Excellent impact resistance and long-term flow stability. This invention innovatively introduces a "stress relief groove" spanning the diameter at the bottom of the limiting screw and covers it with a buffer contact layer, forming a mechanical filter structure that combines rigidity and flexibility, effectively absorbing the kinetic energy of piston impact; at the same time, combined with the double-nut anti-loosening design of the "handwheel and tightening wheel" on the cylinder cover, it helps to solve industry pain points such as loosening of transmission threads and drift of flow setpoint caused by long-term high-frequency pneumatic impact and pipeline vibration, achieving calibration-free high-precision flow maintenance after millions of cycles.

[0042] 2. Near-zero leakage and high purity assurance. The valve uses a highly corrosion-resistant polytetrafluoroethylene (PTFE) integrated diaphragm valve plate to bear the back pressure of the medium, avoiding the mechanical friction particles generated by traditional valve core assemblies; by configuring upper and lower cylinder cover sealing rings, piston double sealing rings, and multiple O-rings in the rod sleeve, the pneumatic driving gas is effectively isolated from the external environment, achieving a high degree of dynamic and static airtightness (tested to show that under a driving pressure of 0.6MPa, the overall helium leakage rate of the valve is less than 1×10⁻⁶). -9 With a static sealing performance of mbar·L / s, it meets the stringent requirements of semiconductor processes for extremely close to zero leakage and zero contamination.

[0043] 3. Highly efficient integrated anti-rotation transmission and modular design. The complex micron-level stroke adjustment mechanism is highly integrated into the cylinder sleeve. Utilizing the interference fit between the hollow anti-rotation pin and the vertical groove of the sleeve, the rotary adjustment motion is cleverly converted into a pure linear limiting motion, eliminating the precision loss caused by torque transmission. This design not only makes the overall structure more compact, but also, combined with the standardized through-bolt assembly process, significantly improves the yield rate of valve mass production and the convenience of subsequent on-site maintenance. Attached Figure Description

[0044] Figure 1 A three-dimensional schematic diagram of a precision control on / off valve for a semiconductor liquid circuit is shown in an embodiment of the present invention;

[0045] Figure 2 An exploded view of the components of the precision control on / off valve in an embodiment of the present invention is shown;

[0046] Figure 3 A cross-sectional schematic diagram of the precision control on / off valve in an embodiment of the present invention is shown;

[0047] Figure 4 A three-dimensional schematic diagram of the limiting rod assembly of the precision control on / off valve in an embodiment of the present invention is shown;

[0048] Figure 5 A flowchart illustrating an assembly method for a precision control on / off valve for a semiconductor liquid circuit according to an embodiment of the present invention is shown.

[0049] Figure 6 Draw corresponding Figure 5 Assembly diagram for step S1;

[0050] Figure 7 Draw corresponding Figure 5 Assembly diagram for step S2;

[0051] Figure 8 Draw corresponding Figure 5 Assembly diagram for step S3;

[0052] Figure 9 Draw corresponding Figure 5 Assembly diagram for steps S4-S5.

[0053] Figure label:

[0054] 10. Valve seat; 11. Valve port; 12. First flow channel; 12A. First inner bead; 12B. First limit buckle; 12C. First nut; 13. Second flow channel; 13A. Second inner bead; 13B. Second limit buckle; 13C. Second nut;

[0055] 20. Cylinder block; 21. First air port;

[0056] 30. Cylinder top cover; 31. Top cover sealing ring; 32. Second air port; 33. Rod assembly sleeve;

[0057] 40. Piston assembly; 41. Piston body; 42. Upper piston seal; 43. Lower piston seal; 44. Spring;

[0058] 50. Diaphragm valve plate;

[0059] 60. Limiting rod assembly; 61. Lead screw nut; 62. Lead screw nut sealing ring; 63. Limiting lead screw; 63A. Limiting lead screw sealing groove; 63B. Pin hole; 63C. Stress relief groove; 64. Limiting lead screw sealing ring; 65. Anti-rotation pin;

[0060] 71. Handwheel; 72. Tensioner wheel; 73. Set screw;

[0061] 80. Base plate;

[0062] 91. Bolt; 92. Spring washer; 93. Flat washer. Detailed Implementation

[0063] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments for understanding the inventive concept of the present invention, and cannot represent all the embodiments, nor are they explained as the only embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art under the premise of understanding the inventive concept of the present invention are within the scope of protection of the present invention. The "double nut counteracting effect" mentioned in the embodiments and variations of the present invention refers to the mechanical locking mechanism that greatly amplifies the frictional force between the thread profiles by counteracting the contact between the handwheel and the tightening wheel on the screw nut, and is used to keep the thread from rotating and loosening under strong vibration. The "stress relief groove" refers to the groove structure opened across the diameter at the bottom of the limiting screw, which acts as a structural spring and can generate a small amount of elastic bending at the moment of piston impact, thereby weakening and flattening the peak stress and isolating the transmission of shock wave to the precision thread mechanism. The "rotary locking structure" refers to the mechanical connection structure between the cylinder cover and the cylinder body that abandons the traditional fastening bolts and can achieve engagement and fixation by relative deflection at a specific angle. It should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of the present invention, the directional indication is only used to explain the relative positional relationship and movement of the components in a specific posture; if the specific posture changes, the directional indication will also change accordingly. In order to better understand the technical solution of the present invention, the precision control on / off valve of the present invention will be described and explained in further detail below, but it is not intended to be considered as a limitation of the scope of protection of the present invention.

[0064] Figure 1 A three-dimensional schematic diagram of a precision control on / off valve for a semiconductor liquid circuit is shown in an embodiment of the present invention; Figure 2 An exploded view of the components of the precision control on / off valve in an embodiment of the present invention is shown; Figure 3 A cross-sectional schematic diagram of the precision control on / off valve in an embodiment of the present invention is shown; Figure 4 A three-dimensional schematic diagram of the limiting rod assembly of the precision control on / off valve in an embodiment of the present invention is shown.

[0065] A precision control on / off valve for semiconductor fluid circuits is used in the equipment supply chain of the semiconductor manufacturing industry. Specifically, it can be applied to the on / off and precise flow control of high-purity chemicals and electronic ultrapure water in semiconductor process equipment pipelines such as wet cleaning, electroplating, coating and developing, and chemical mechanical polishing (CMP). The product application requirements of the precision control on / off valve include: high back pressure, corrosion resistance, high temperature resistance, clean valve cavity with no dead zone, extremely close to zero leakage, and sealing performance with almost no particle and ion precipitation.

[0066] See Figure 1 and Figure 2This application discloses a precision control on / off valve for semiconductor liquid circuits, comprising: a valve seat 10 providing a flow channel, a cylinder body 20 and a cylinder cover 30 providing space for the piston assembly 40 and the limit rod assembly 60, a diaphragm valve plate 50 serving as a valve switch, an adjusting wheel for adjusting the valve opening, and a base plate 80 mounted on the bottom of the valve seat 10.

[0067] Regarding valve seat 10, refer to... Figure 1 , Figure 2 and Figure 3 The valve seat 10 has a valve port 11 and a first flow channel 12 and a second flow channel 13 communicating with the valve port 11. The surface finish of the flow channels meets the requirement Ra≤0.1μm. In this example, the first flow channel 12 is the liquid inlet flow channel. The valve outlet of the first flow channel 12 can be equipped with a first inner bead 12A, a first limiting buckle 12B, and a first nut 12C. The first inner bead 12A is used for auxiliary positioning and sealing. When connected to the liquid inlet pipeline, the first inner bead 12A can form an initial fit or buffer with the main pipeline to help with positioning and connection. The first nut 12C engages with the thread on the valve outlet to generate an axial clamping force. The clamping force acts on the first inner bead 12A, causing the first inner bead 12A to press against the liquid inlet pipeline, forming a reliable sealed connection. The first limiting buckle 12B is used to limit the axial movement range of the first nut 12C, thereby limiting the axial movement range of the first inner bead 12A. The second flow channel 13 is a liquid outlet flow channel. The valve outlet of the second flow channel 13 can be equipped with a second inner bead 13A, a second limiting buckle 13B, and a second nut 13C. The functions of the second inner bead 13A, the second limiting buckle 13B, and the second nut 13C at the valve outlet of the second flow channel 13 are similar to those of the first inner bead 12A, the first limiting buckle 12B, and the first nut 12C at the valve outlet of the first flow channel 12, and will not be elaborated further here. After the fluid enters the first flow channel 12, it reaches the second flow channel 13 through the valve port 11 and is discharged from the valve outlet of the second flow channel 13. The diaphragm valve plate 50 is located on the valve port 11 and connected to the piston assembly 40, and is pneumatically controlled to achieve valve on / off control. Simultaneously, the limiting rod assembly 60 can precisely control the maximum upward movement position of the piston assembly 40 and the diaphragm valve plate 50, thereby achieving precise valve opening control.

[0068] Regarding cylinder block 20 and cylinder head 30, refer to... Figure 2 and Figure 3A pre-assembled cylinder body 20 and cylinder cover 30 are mounted on a valve seat 10. A piston assembly 40 is disposed inside the cylinder body 20, and a limit rod assembly 60 is connected inside the cylinder cover 30. The piston assembly 40 is connected to the limit rod assembly 60. The cylinder body 20 and the cylinder cover 30 are connected by a rotary locking structure to form an active space for the piston assembly 40 and the limit rod assembly 60. A first air hole 21 communicating with this active space is opened on the side wall of the cylinder body 20, and a second air hole 32 communicating with this active space is opened on the side wall of the cylinder cover 30. A cover sealing ring 31 is installed at the connection between the cylinder body 20 and the cylinder cover 30, and the cover sealing ring 31 is used to seal the gap between the cylinder body 20 and the cylinder cover 30. The rotary locking structure includes a cover lock on the cylinder cover 30 and a cylinder lock on the cylinder body 20, which are configured to engage through relative rotation. In a preferred embodiment, to improve the airtightness of the cylinder assembly and minimize leakage of compressed gas driving the piston assembly 40 from the limit rod assembly 60 and the adjusting wheel, a rod sleeve 33 is specially provided on the top of the cylinder cover 30. Specifically, a mounting hole is provided at the center of the top of the cylinder cover 30, and the inner wall of the mounting hole is provided with internal threads. The rod sleeve 33 has a hollow cylindrical structure, and its upper outer wall is provided with external threads that mate with the inner wall of the mounting hole, allowing it to be screwed in and fixed at the top opening of the cylinder cover 30 and extending into the internal cavity of the cylinder cover 30. The internal cavity structure of the rod sleeve 33 is segmented, including an upper adjusting section, a middle sealing section, and a lower snap-fit ​​section. The upper adjusting section of the sleeve's inner cavity is machined with precision internal threads to mate with the threaded section of the limiting rod assembly 60. By rotating the adjusting wheel, the limiting rod assembly 60 can be precisely raised and lowered axially. The middle sealing section of the sleeve's inner cavity has a smooth cylindrical inner surface, which forms a sealing mating surface with the corresponding surfaces of the lead screw nut 61 and the limiting lead screw 63 of the limiting rod assembly 60, achieving dynamic sealing and effectively improving the airtightness of the cylinder assembly. The lower snap-fit ​​section of the sleeve's inner cavity has a vertical limiting slot that mates with the anti-rotation pin 65 of the limiting rod assembly 60, restricting the rotation of the limiting lead screw 63 so that the limiting lead screw 63 can only move up and down.

[0069] Regarding piston assembly 40, refer to... Figure 2 and Figure 3The piston assembly 40 includes a pre-assembled piston body 41, an upper piston sealing ring 42, a lower piston sealing ring 43, and a spring 44. The piston body 41 has an upper sealing groove and a lower sealing groove. The upper piston sealing ring 42 and the lower piston sealing ring 43 are pre-fitted into the corresponding upper and lower sealing grooves on the piston body 41. The piston body 41 is installed inside the cylinder body 20. The upper piston sealing ring 42 and the lower piston sealing ring 43 seal the gap between the piston body 41 and the cylinder body 20 to further improve the airtightness of the cylinder assembly. The spring 44 is installed inside the cylinder body 20 on the piston body 41 and is fitted over the rod sleeve 33. Testing showed that, under a driving pressure of 0.6 MPa, the overall helium leakage rate of the valve was less than 1 × 10⁻⁶. -9 Static sealing performance in mbar·L / s.

[0070] Regarding diaphragm valve plate 50, refer to... Figure 2 and Figure 3 The diaphragm valve plate 50 is mounted on the bottom of the piston body 41 and housed within the valve seat 10. The diaphragm valve plate 50 is integrally formed from highly corrosion-resistant polytetrafluoroethylene (PTFE) material and mainly includes a sealing diaphragm portion and a valve core integrally located at its center. The main body of the sealing diaphragm portion is used to withstand the back pressure impact of the fluid, and its outermost periphery has a sealing hook. This sealing hook has an overall annular protrusion structure and is configured to achieve an interference fit with a sealing groove on the valve seat 10 to form a seal. The valve core is located at the center of the diaphragm valve plate 50 and has an upper threaded portion and a lower valve core platform. The threaded portion is used to engage with the external thread at the bottom end of the piston body 41 to connect the diaphragm valve plate 50 to the piston assembly 40. The valve core platform is located at the valve port 11 of the valve seat 10 and is driven by the cylinder assembly to seal or disengage from the valve port 11.

[0071] Regarding limit lever assembly 60, refer to... Figure 2 , Figure 3 and Figure 4The limiting rod assembly 60 is connected to the rod assembly sleeve 33 of the cylinder upper cover 30, and includes a lead screw nut 61, a lead screw nut sealing ring 62, a limiting lead screw 63, a limiting lead screw sealing ring 64, and an anti-rotation pin 65. The lead screw nut 61 is connected to the rod assembly sleeve 33 of the cylinder upper cover 30 and extends from the top opening of the cylinder upper cover 30. The lead screw nut 61 has a hollow cylindrical structure, with a precision internal thread on its inner surface and an external thread on its outer surface for mating with the adjusting wheel. The lower outer side of the lead screw nut 61 has a lead screw nut sealing groove 61A for installing the lead screw nut sealing ring 62. The limiting lead screw 63 is connected to the lead screw nut 61 inside the rod assembly sleeve 33. The upper part of the limiting lead screw 63 is a long rod with a precision external thread, and the lower part is a cylindrical limiting head with a larger diameter. The upper external thread of the limiting screw 63 is screwed into the internal thread of the screw nut 61, forming a precision helical transmission pair. A limiting screw sealing groove 63A is provided on the outer circumferential surface of the cylindrical limiting head of the limiting screw 63 to accommodate the limiting screw sealing ring 64. The screw nut sealing ring 62 seals the gap between the screw nut 61 and the rod assembly sleeve 33, and the limiting screw sealing ring 64 seals the gap between the limiting screw 63 and the rod assembly sleeve 33, forming a sliding seal between the limiting rod assembly 60 and the inner wall of the rod assembly sleeve 33, ensuring the airtightness of the pneumatic control chamber and preventing drive gas leakage. A through pin hole 63B is provided on the side wall of the limiting head of the limiting screw 63 for installing an anti-rotation pin 65. The anti-rotation pin 65 is a hollow, radially elastic cylindrical pin with an outer diameter slightly larger than the inner diameter of the pin hole 63B. It is pressed into the pin hole 63B through an interference fit. The hollow structure provides radial elastic tension to the pin, allowing it to be firmly tightened within the pin hole 63B. After the anti-rotation pin 65 is installed, both ends protrude from the side surface of the limiting screw 63 and are embedded in the vertical limiting groove of the rod sleeve 33. Because the anti-rotation pin 65 is engaged in the vertical limiting groove, the limiting screw 63 cannot rotate with the screw nut 61, but instead moves up and down. In a preferred embodiment, to eliminate the rigid impact of the piston body 41 during high-speed upward impact, a stress relief groove 63C is formed on the bottom surface of the limiting screw 63. The stress relief groove 63C spans the diameter direction of the limiting screw 63, dividing the bottom surface of the limiting screw 63 into two symmetrical pressure-bearing areas. The stress relief groove 63C functions as a structural spring in mechanical terms. When the piston impacts the bottom, the two semi-circular metal blocks at the bottom are allowed to undergo a slight elastic bending. This deliberate reduction in structural stiffness flattens the peak stress at the moment of impact, greatly reducing the transmission of the shock wave to the threaded adjustment mechanism, thus acting as a rigid filter.Furthermore, the bottom surface of the limiting screw 63 can be further covered with a buffer contact layer. This buffer contact layer can be a buffer pad embedded or attached to the bottom end, made of a high-damping elastic material (such as polyurethane (PU), nitrile rubber (NBR), or fluororubber (FKM)). When the piston body 41 moves upward at full speed and impacts the limiting screw 63, the buffer pad first contacts the piston body 41 and undergoes elastic compression. During this compression process, most of the piston's kinetic energy is converted into the internal energy of the pad and dissipated, achieving a soft landing. This soft-hard combined buffer design eliminates impact noise. More importantly, it isolates the impact of pneumatic shocks on the precision adjusting thread, ensuring that the valve's manually set maximum flow rate remains accurate even after millions of opening and closing cycles, without the need for frequent calibration.

[0072] Regarding the adjusting wheel, please refer to... Figure 2 and Figure 3 The adjusting wheel is mounted on the cylinder cover 30 and includes a handwheel 71, a tensioning wheel 72, and a set screw 73. Both the handwheel 71 and the tensioning wheel 72 are associated with a lead screw nut 61, and the set screw 73 is used to lock the handwheel 71 to the lead screw nut 61. The upper end of the lead screw nut 61 extends from the top of the cylinder cover 30. The handwheel 71 and the tensioning wheel 72 are screwed into the lead screw nut 61 in sequence. The handwheel 71 is located above the tensioning wheel 72, and the outer diameter of the handwheel 71 is the same as or slightly larger than that of the tensioning wheel 72. The set screw 73 is installed in a radial threaded hole on the side of the handwheel 71 to lock the handwheel to the lead screw nut 61. During flow setting, the user can rotate the lead screw nut 61 via handwheel 71, causing the limiting lead screw 63 to undergo axial displacement. This changes the upper limit of the stroke of the piston body 41 and the diaphragm valve plate 50, achieving precise flow adjustment. After flow setting, to prevent the lead screw nut 61 from rotating under long-term vibration, the user can rotate the tightening wheel 72 in the opposite direction, causing it to move upwards and tightly contact the lower surface of the handwheel 71. At this time, the handwheel 71 and the tightening wheel 72 form a double-nut opposing effect on the threads of the lead screw nut 61, greatly amplifying the friction between the thread profiles. Even under strong air hammer effects or external mechanical vibrations, the adjusted flow set point remains unchanged, thus suppressing the flow drift phenomenon commonly seen in semiconductor liquid delivery and ensuring that the flow setting accuracy does not drift. In an optimized embodiment, a Hall sensor or laser displacement measurement module can be embedded in the top of the handwheel 71. This module monitors the axial position of the limiting lead screw 63 in real time and converts it into a digital signal, transmitting it to the central control system (MCS), achieving dual protection of manual adjustment and digital monitoring.

[0073] Regarding the base plate 80, refer to... Figure 2 and Figure 3The base plate 80 is installed at the bottom of the valve seat 10. The base plate 80 is provided with a base plate threaded hole. The cylinder cover 30, the cylinder body 20 and the valve seat 10 are provided with through holes corresponding to the base plate threaded hole. A flat washer 93 and a spring washer 92 are installed at the through hole of the cylinder cover 30, and bolts 91 pass through the cylinder cover 30, the cylinder body 20 and the valve seat 10 in sequence and lock with the base plate threaded hole of the base plate 80.

[0074] In one example, initially, the limiting screw 63 is screwed into the internal threaded hole of the screw nut 61 via a precision adjusting thread on its outer periphery. To achieve micron-level opening control, the precision adjusting thread is preferably a fine-pitch thread with a pitch P set between 0.5 mm and 0.75 mm. The top of the screw nut 61 is fixedly connected to the handwheel 71, so that the angular displacement of the handwheel 71 can be synchronously converted into the rotational movement of the screw nut 61. When it is necessary to initially set or finely adjust the flow rate of the semiconductor fluid circuit, the tensioning wheel 72 located below the handwheel 71 is first manually loosened. The tensioning wheel 72 is threaded onto the outer periphery of the screw nut 61, and the loosening action releases the axial pre-tightening lock between the handwheel 71 and the top surface of the cylinder cover 30. Subsequently, the operator rotates the handwheel 71, which drives the screw nut 61 to rotate in place within the bearing hole of the cylinder cover 30. During this process, because the lower part of the limiting screw 63 is restricted by the anti-rotation pin 65, the limiting screw 63 is prohibited from rotating synchronously with the screw nut 61, thus forcing a purely axial lifting motion. According to the principle of screw transmission, for each rotation of the handwheel 71, the limiting screw 63 moves axially by one pitch P. Since the circumference of the handwheel 71 is provided with 50 equally divided laser-engraved graduation lines, for each graduation moved by the operator, the axial displacement increment of the limiting screw 63 is only P / 50 (for example, when the pitch is 0.5mm, the single-division adjustment accuracy is as high as 10μm). The bottom end of the limiting screw 63 extends to the space above the piston assembly 40, forming an adjustable physical stop. When the cylinder assembly is supplied with air to drive the piston body 41 to move upward to open the valve, the top end face of the piston body 41 will eventually impact and abut against the bottom end of the limiting screw 63. Therefore, by precisely changing the axial height of the limiting screw 63, the maximum upward stroke of the piston body 41 can be physically limited, thereby precisely controlling the flow cross-sectional area between the diaphragm valve plate 50 and the valve seat 10 orifice 11, achieving constant control of the flow rate of highly corrosive chemicals or ultrapure water. After adjustment, the tightening wheel 72 is tightened in the opposite direction. The tightening wheel 72 and the handwheel 71 apply opposite preload forces to the screw nut 61 in the axial direction, generating a double nut counteracting effect, completely eliminating radial and axial clearances between the threaded pairs. In addition, the stress relief groove 63C provided at the bottom of the limiting screw 63 plays a crucial role at this time: when the piston body 41 frequently impacts the limiting screw 63 at high speed, the stress relief groove 63C absorbs and interferes with the transmission path of the shock wave through local micro-elastic deformation, preventing high-frequency vibration from causing the threaded pairs to loosen or the flow rate to drift, ensuring that the long-term repeatability accuracy of the valve opening remains within ±1% in the semiconductor high-frequency cleaning process.

[0075] Figure 5 A flowchart illustrating an assembly method for a precision control on / off valve for a semiconductor liquid circuit according to an embodiment of the present invention is shown. (Refer to...) Figure 5This invention also discloses an assembly method for a precision control on / off valve, encompassing steps S1 to S5. Specifically, step S1 involves setting a limiting rod assembly 60 within the cylinder upper cover 30 and installing an adjusting wheel on the cylinder upper cover 30. Step S2 involves setting a piston assembly 40 within the cylinder body 20. Step S3 involves connecting the cylinder body 20 and the cylinder upper cover 30. Step S4 involves installing a diaphragm valve plate 50 at the lower end of the piston assembly 40. Step S5 involves connecting the valve seat 10 with the cylinder body 20 and the cylinder upper cover 30.

[0076] Figure 6 Draw corresponding Figure 5 Assembly diagram for step S1. The operation of step S1 can be found in [reference needed]. Figure 6A limiting rod assembly 60 is installed inside the cylinder upper cover 30, and an adjusting wheel is installed on the cylinder upper cover 30. Specifically, step S1 includes: fitting a lead screw nut sealing ring 62 onto a lead screw nut 61, and screwing the lead screw nut 61 with the sealing ring 62 into the cylinder upper cover 30; fitting a limiting lead screw sealing ring 64 onto a limiting lead screw 63, and screwing the limiting lead screw 63 with the sealing ring 64 into the lead screw nut 61; screwing a tightening wheel 72 and a handwheel 71 sequentially into the lead screw nut 61 at the top of the cylinder upper cover 30, and locking the handwheel 71 to the lead screw nut 61 with a set screw 73; and installing an anti-rotation pin 65 at the bottom of the limiting lead screw 63. The cylinder body 20 has a first air hole 21 communicating with the movable space on its side wall, and the cylinder upper cover 30 has a second air hole 32 communicating with the movable space on its side wall. In a preferred embodiment, to improve the airtightness of the cylinder assembly after subsequent assembly and to minimize leakage of compressed gas driving the piston assembly 40 from the limiting rod assembly 60 and the adjusting wheel, a rod sleeve 33 is specially provided on the top of the cylinder cover 30. Specifically, a mounting hole is provided at the center of the top of the cylinder cover 30, and the inner wall of the mounting hole is provided with internal threads. The rod sleeve 33 has a hollow cylindrical structure, and its upper outer wall is provided with external threads that mate with the inner wall of the mounting hole, allowing it to be screwed into and fixed at the top opening of the cylinder cover 30 and extending into the internal cavity of the cylinder cover 30. The internal cavity structure of the rod sleeve 33 is segmented, including an upper adjusting section, a middle sealing section, and a lower snap-fit ​​section. The upper adjusting section of the sleeve cavity is machined with precision internal threads to mate with the threaded section of the limiting rod assembly 60. By rotating the adjusting wheel, the limiting rod assembly 60 can be driven to move precisely axially. The middle sealing section of the sleeve cavity has a smooth cylindrical inner surface, which forms a dynamic seal with the corresponding surfaces of the lead screw nut 61 and the lead screw 63 of the limiting rod assembly 60, thereby effectively improving the airtightness of the cylinder assembly. The lower locking section of the sleeve cavity has a vertical limiting groove that engages with the anti-rotation pin 65 of the limiting rod assembly 60, restricting the rotation of the lead screw 63 so that it can only move up and down. The adjusting wheel is mounted on the cylinder cover 30 and includes a handwheel 71, a tensioning wheel 72, and a set screw 73. The handwheel 71 and the tensioning wheel 72 are both associated with the lead screw nut 61, and the set screw 73 is used to lock the handwheel 71 to the lead screw nut 61. The upper end of the lead screw nut 61 extends from the top of the cylinder cover 30. The tensioning wheel 72 and the handwheel 71 are screwed into the lead screw nut 61 in sequence. The handwheel 71 is located above the tensioning wheel 72, and the outer diameter of the handwheel 71 is the same as or slightly larger than that of the tensioning wheel 72. The set screw 73 is installed in the radial threaded hole on the side of the handwheel 71 to lock the handwheel and the lead screw nut 61.During flow setting, the user can rotate the lead screw nut 61 via handwheel 71, causing the limiting lead screw 63 to undergo axial displacement. This changes the upper limit of the stroke of the piston body 41 and the diaphragm valve plate 50, achieving precise flow adjustment. After flow setting is completed, to prevent the lead screw nut 61 from rotating under long-term vibration, the user can rotate the tightening wheel 72 in the opposite direction, causing it to move upward and tightly contact the lower surface of the handwheel 71. At this time, the handwheel 71 and the tightening wheel 72 form a double-nut opposing effect on the threads of the lead screw nut 61, greatly amplifying the friction between the thread profiles. Even under strong air hammer effect or external mechanical vibration, the adjusted flow set point remains unchanged, thereby suppressing the flow drift phenomenon commonly seen in semiconductor liquid delivery and ensuring that the flow setting accuracy does not drift.

[0077] Figure 7 Draw corresponding Figure 5 Assembly diagram for step S2. The operation of step S2 can be found by referring to... Figure 7 A piston assembly 40 is installed inside the cylinder body 20. Step S2 specifically includes: fitting the upper piston sealing ring 42 and the lower piston sealing ring 43 onto the piston body 41, and placing the piston body 41 with the upper piston sealing ring 42 and the lower piston sealing ring 43 inside the cylinder body 20; installing a spring 44 on the piston body 41 inside the cylinder body 20; and installing an upper cover sealing ring 31 onto the cylinder body 20. The piston assembly 40 includes a pre-assembled piston body 41, an upper piston sealing ring 42, a lower piston sealing ring 43, and a spring 44. The piston body 41 has an upper sealing groove and a lower sealing groove, and the upper piston sealing ring 42 and the lower piston sealing ring 43 are pre-fitted into the corresponding upper and lower sealing grooves on the piston body 41. The piston body 41 is installed inside the cylinder body 20. The upper piston sealing ring 42 and the lower piston sealing ring 43 are used to seal the gap between the piston body 41 and the cylinder body 20, so as to further improve the airtightness of the cylinder assembly. The spring 44 is installed on the piston body 41 inside the cylinder body 20 and is sleeved on the outside of the rod assembly sleeve 33.

[0078] Figure 8 Draw corresponding Figure 5 Assembly diagram for step S3. The operation of step S3 can be found in [reference needed]. Figure 8 The cylinder body 20 and cylinder top cover 30 are combined. The cylinder top cover 30, which is equipped with the limiting rod assembly 60 and the adjusting wheel, and the cylinder body 20, which is equipped with the piston assembly 40, are fastened together by a locking connection to form a cylinder assembly. A top cover sealing ring 31 is installed at the connection between the cylinder body 20 and the cylinder top cover 30, and the top cover sealing ring 31 is used to seal the gap between the cylinder body 20 and the cylinder top cover 30.

[0079] Figure 9 Draw corresponding Figure 5 Assembly diagrams for steps S4-S5. The procedures for steps S4-S5 can be found by referring to... Figure 9 Step S4 involves installing the diaphragm valve plate 50 at the lower end of the piston assembly 40, wherein the diaphragm valve plate 50 is installed at the bottom of the piston body 41. The diaphragm valve plate 50 is integrally molded from highly corrosion-resistant polytetrafluoroethylene (PTFE) material and mainly includes a sealing diaphragm portion and a valve core integrally located at its center. The main body of the sealing diaphragm portion is used to withstand the back pressure impact of the fluid, and has a sealing hook at its outermost periphery. The sealing hook has an overall annular protrusion structure and is configured to subsequently achieve an interference fit with the sealing groove on the valve seat 10 to form a seal. The valve core is located at the center of the diaphragm valve plate 50 and has a threaded portion at the upper part and a valve core platform at the lower part. The threaded portion is used to engage with the external thread at the bottom end of the piston body 41 to associate the diaphragm valve plate 50 with the piston assembly 40. After the cylinder body 20 is combined with the valve seat 10, the valve core platform is located at the valve port 11 of the valve seat 10 and is driven by the cylinder assembly to seal or disengage from the valve port 11.

[0080] Step S5 combines the valve seat 10 with the cylinder body 20 and cylinder top cover 30. Specifically, the cylinder body 20 and cylinder top cover 30 are installed on the valve seat 10, a base plate 80 is assembled at the bottom of the valve seat 10, and the cylinder assembly and the diaphragm valve plate 50 are assembled at the top of the valve seat 10. Then, a flat washer 93 and a spring washer 92 are sequentially installed in the through hole of the cylinder assembly, and a bolt 91 is inserted into the through hole and locked to the internal thread of the base plate 80. The valve seat 10 has a valve port 11 and a first flow channel 12 and a second flow channel 13 communicating with the valve port 11. The surface finish of the flow channels satisfies Ra≤0.1μm. In this example, the first flow channel 12 is a liquid inlet flow channel, and the valve outlet of the first flow channel 12 can be equipped with a first inner bead 12A, a first limiting buckle 12B, and a first nut 12C. The first inner bead 12A is used for auxiliary positioning and sealing. When connected to the inlet pipe, the first inner bead 12A can form an initial fit or buffer with the main pipe to help with positioning and connection. The first nut 12C engages with the thread on the valve outlet to generate an axial clamping force. This clamping force acts on the first inner bead 12A, causing the first inner bead 12A to press against the inlet pipe, forming a reliable sealed connection. The first limiting buckle 12B is used to limit the axial movement range of the first nut 12C, thereby limiting the axial movement range of the first inner bead 12A. The second flow channel 13 is a liquid outlet flow channel. The valve outlet of the second flow channel 13 may be equipped with a second inner bead 13A, a second limiting buckle 13B, and a second nut 13C. The functions of the second inner bead 13A, the second limiting buckle 13B, and the second nut 13C at the valve outlet of the second flow channel 13 are similar to the functions of the first inner bead 12A, the first limiting buckle 12B, and the first nut 12C at the valve outlet of the first flow channel 12, and will not be described in detail here.

[0081] The precision control on / off valve provided in the embodiments and variations of this invention has the following working principle: When no air source enters or the solenoid valve is de-energized, the piston assembly 40 is driven downward by the elastic preload of the spring 44, causing the diaphragm valve plate 50 to press tightly against the valve port 11 of the valve seat 10, cutting off the fluid path between the first flow channel 12 and the second flow channel 13, thus achieving a seal. When pneumatically opened, compressed air enters the cylinder body 20 through the second air hole 32, overcoming the resistance of the spring 44 and pushing the piston body 41 upward, thereby causing the diaphragm valve plate 50 to disengage from the valve port 11. At this time, the bottom end face of the limiting screw 63 acts as a rigid stop point, physically limiting the maximum upward stroke of the piston body 41. The operator rotates the handwheel 71 to drive the screw nut 61 to rotate, causing the limiting screw 63 to move up and down slightly along the axial direction. Because the lifting and lowering of the limiting screw 63 directly changes the upward movement height of the piston body 41, it alters the flow clearance between the diaphragm valve plate 50 and the valve port 11, enabling precise control of the flow rate of semiconductor chemicals or ultrapure water. After adjustment, tighten the clamping wheel 72, utilizing the double nut counteracting effect to eliminate the threaded pair clearance, and in conjunction with the stress relief groove 63C on the limiting screw 63 to counteract the vibration generated by the pneumatic impact, ensuring that the set flow point does not shift during tens of thousands of cycles.

[0082] The specific embodiments and variations provided by the present invention have the following corresponding technical effects to achieve a significant improvement over the prior art:

[0083] 1. High Precision and High Stability: By incorporating a limit rod assembly with fine threads and a locking structure, this application solves the flow drift problem that traditional valves are prone to in the high-frequency vibration environment of semiconductor processes. The adjustment accuracy can reach the micrometer level, meeting the stringent requirements of 12-inch wafer wet processing for reagent ratios. Through testing on a 12-inch wafer production line of a memory manufacturing company, the use of the precision control on / off valve described in this application improved flow stability in the cleaning process by 42%, and reduced wafer edge yield loss due to flow drift by 15%.

[0084] 2. Stress isolation and long service life protection: An innovative stress relief groove is designed at the bottom of the limit screw. This structure acts as a rigid filter, effectively absorbing the shock wave of the piston impact and preventing the vibration from being directly transmitted to the adjusting thread mechanism. This protects the precision threads from damage and significantly improves the service life of the valve.

[0085] 3. Tool-free quick installation and high cleanliness: The top cover and cylinder body adopt a rotary locking structure to replace the traditional multi-bolt flange connection, which not only greatly shortens the assembly and maintenance time, but more importantly, avoids metal particles generated by friction during the disassembly and assembly of metal bolts, ensuring the ultra-high cleanliness of the semiconductor liquid circuit system.

[0086] 4. Optimized pneumatic response: The coaxial linkage design of the limit rod assembly and piston assembly reduces the eccentric torque of the moving parts, making the valve more stable and smooth when switching between opening and closing, and reducing the impact risk of water hammer effect on the upstream precision filter.

[0087] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A precision control on / off valve for semiconductor liquid circuits, characterized in that, include: Valve seat (10), the valve seat (10) is provided with valve port (11) and a first flow channel (12) and a second flow channel (13) connecting the valve port (11); A cylinder assembly is attached to the valve seat (10). The cylinder assembly includes a cylinder body (20), a cylinder cover (30), and a piston assembly (40). The cylinder cover (30) is connected to the cylinder body (20) via a rotary locking structure. The piston assembly (40) is assembled inside the cylinder body (20). A limit rod assembly (60) is connected inside the cylinder cover (30). The cylinder cover (30) and the cylinder body (20) can provide space for the piston assembly (40) and the limit rod assembly (60). The limit rod assembly (60) includes an interconnected lead screw nut (61) and a limit lead screw (63). The limit rod assembly (60) is used to limit the maximum upward position of the piston assembly (40) to limit the valve opening. A diaphragm valve plate (50) is connected to the piston assembly (40) and housed within the valve seat (10). The diaphragm valve plate (50) has a valve core located at the valve port (11) at the center. The valve core is configured to be driven by the cylinder assembly to seal or disengage from the valve port (11). An adjusting wheel is provided on the cylinder upper cover (30) and connected to the screw nut (61) of the limiting rod assembly (60). It is used to adjust the lifting and lowering of the limiting screw (63) in the cylinder upper cover (30) to adjust the maximum upward position of the piston assembly (40) and the valve core. The cylinder body (20) and the cylinder top cover (30) are connected by a top cover sealing ring (31), which is used to seal the gap between the cylinder body (20) and the cylinder top cover (30). The cylinder top cover (30) has a top opening, and a rod sleeve (33) extending into the cylinder top cover (30) is connected to the top opening. The rod sleeve (33) has a hollow inner cavity, which includes an adjusting thread section at the top and a sealing mating surface at the middle. The lead screw nut (61) is connected inside the rod sleeve (33), wherein the upper part of the lead screw nut (61) is... The screw is associated with the adjusting thread section. The lower part of the screw nut (61) is provided with a screw nut sealing ring (62), which is used to seal the gap between the screw nut (61) and the rod sleeve (33). The limiting screw (63) is connected to the screw nut (61) inside the rod sleeve (33). The upper part of the limiting screw (63) is associated with the screw nut (61). The lower part of the limiting screw (63) is provided with a limiting screw sealing ring (64), which is used to seal the gap between the limiting screw (63) and the rod sleeve (33). The hollow inner cavity of the rod sleeve (33) further includes a vertical limiting groove located at the lower part. The lower part of the limiting screw (63) is provided with an anti-rotation pin (65) located below the limiting screw sealing ring (64). The anti-rotation pin (65) cooperates with the vertical limiting groove to suppress the rotation of the limiting screw (63). The anti-rotation pin (65) is a hollow cylindrical pin. Among them, the bottom surface of the limiting screw (63) is provided with a stress relief groove (63C), the stress relief groove spans the diameter direction of the limiting screw (63), dividing the bottom surface of the limiting screw (63) into two symmetrical pressure bearing areas, and the bottom surface of the limiting screw (63) is also covered with a buffer contact layer. The adjusting wheel includes a tensioning wheel (72) and a handwheel (71) sequentially arranged on the cylinder cover (30). Both the handwheel (71) and the tensioning wheel (72) are associated with the lead screw nut (61). The handwheel (71) is equipped with a set screw (73). The set screw (73) is used to lock the handwheel (71) and the lead screw nut (61). The handwheel (71) is configured to drive the lead screw nut (61) to rotate during the flow setting process, so that the limiting lead screw (63) moves up and down. The tensioning wheel (72) is configured to abut against the handwheel (71) after the flow setting process.

2. The precision control on / off valve for semiconductor liquid circuits according to claim 1, characterized in that, The piston assembly (40) includes a piston body (41), an upper piston seal ring (42), a lower piston seal ring (43), and a spring (44). The piston body (41) is provided with an upper sealing groove and a lower sealing groove. The upper piston seal ring (42) is located in the upper sealing groove, and the lower piston seal ring (43) is located in the lower sealing groove. The upper piston seal ring (42) and the lower piston seal ring (43) are used to seal the gap between the piston body (41) and the cylinder body (20). The spring (44) is installed on the piston body (41) and is sleeved on the outside of the rod assembly sleeve (33).

3. The precision control on / off valve for semiconductor fluid circuits according to any one of claims 1-2, characterized in that, It also includes a base plate (80), which is installed at the bottom of the valve seat (10). The base plate (80) is provided with a base plate threaded hole. The cylinder cover (30), the cylinder body (20), and the valve seat (10) are provided with through holes corresponding to the threaded holes of the base plate. A flat washer (93) and a spring washer (92) are installed at the through holes of the cylinder cover (30), and the bolts are... (91) Pass through the cylinder cover (30), the cylinder body (20) and the valve seat (10) in sequence and lock them to the bottom plate threaded hole of the bottom plate (80).

4. A method for assembling a precision control on / off valve for a semiconductor liquid circuit, characterized in that, Includes the following steps: S1. A limit rod assembly (60) is set inside the cylinder cover (30), and an adjusting wheel is installed on the cylinder cover (30); wherein, the limit rod assembly (60) includes a lead screw nut (61) and a limit lead screw (63) that are interconnected, and the adjusting wheel is connected to the lead screw nut (61) of the limit rod assembly (60) for adjusting the lifting and lowering of the limit lead screw (63) in the cylinder cover (30); S2. Install the piston assembly (40) inside the cylinder body (20); S3. Combine the cylinder body (20) with the cylinder top cover (30); wherein the cylinder top cover (30) and the cylinder body (20) are connected by a rotary locking structure, so that the cylinder top cover (30) and the cylinder body (20) provide the piston assembly (40) and the limiting rod group (60) for movement, and limit the maximum upward movement position of the piston assembly (40) by the limiting rod group (60); S4. Install the diaphragm valve plate (50) at the lower end of the piston assembly (40); S5. The valve seat (10) is combined with the cylinder body (20) and the cylinder cover (30); wherein the valve seat (10) is provided with a valve port (11) and a first flow channel (12) and a second flow channel (13) connecting the valve port (11), the diaphragm valve plate (50) is housed in the valve seat (10), the diaphragm valve plate (50) has a valve core located at the center, the valve core is located at the valve port (11), wherein the valve core is configured to be driven by the cylinder assembly to seal or disengage from the valve port (11). In step S1, the cylinder top cover (30) has a top opening, and a rod sleeve (33) extending into the cylinder top cover (30) is connected to the top opening. The rod sleeve (33) has a hollow inner cavity, which includes an adjusting threaded section at the top and a sealing mating surface at the middle. The lead screw nut (61) is connected to the rod sleeve (33), wherein the upper part of the lead screw nut (61) is associated with the adjusting threaded section. The lower part of the rod nut (61) is provided with a screw nut sealing ring (62), which is used to seal the gap between the screw nut (61) and the rod assembly sleeve (33); the limiting screw (63) is connected to the screw nut (61) inside the rod assembly sleeve (33), wherein the upper part of the limiting screw (63) is associated with the screw nut (61), and the lower part of the limiting screw (63) is provided with a limiting screw sealing ring (64), which is used to seal the gap between the screw nut (61) and the rod assembly sleeve (33). The ring (64) is used to seal the gap between the limiting screw (63) and the rod sleeve (33); the hollow inner cavity of the rod sleeve (33) also includes a vertical limiting groove located at the lower part, and an anti-rotation pin (65) located below the limiting screw sealing ring (64) is provided on the lower part of the limiting screw (63). The anti-rotation pin (65) cooperates with the vertical limiting groove to suppress the rotation of the limiting screw (63); a stress relief groove is opened on the bottom surface of the limiting screw (63). (63C), the stress relief groove spans the diameter direction of the limiting screw (63), dividing the bottom surface of the limiting screw (63) into two symmetrical pressure-bearing areas, and the bottom surface of the limiting screw (63) is also covered with a buffer contact layer; the adjusting wheel includes a tensioning wheel (72) and a handwheel (71) arranged sequentially on the cylinder cover (30), the handwheel (71) and the tensioning wheel (72) are both associated with the screw nut (61), and the handwheel (71) is equipped with a set screw (73): The set screw (73) is used to lock the handwheel (71) and the lead screw nut (61). The handwheel (71) is configured to drive the lead screw nut (61) to rotate during the flow setting process, so that the limit lead screw (63) moves up and down. The tensioning wheel (72) is configured to abut against the handwheel (71) after the flow setting process.

5. The assembly method of the precision control on / off valve for semiconductor liquid circuits according to claim 4, characterized in that, In step S2, the piston assembly (40) includes a piston body (41), an upper piston seal ring (42), a lower piston seal ring (43), and a spring (44); the piston body (41) is provided with an upper sealing groove and a lower sealing groove, the upper piston seal ring (42) is disposed in the upper sealing groove, and the lower piston seal ring (43) is disposed in the lower sealing groove. The upper piston seal ring (42) and the lower piston seal ring (43) are used to seal the gap between the piston body (41) and the cylinder body (20); the spring (44) is mounted on the piston body (41). And it is sleeved outside the rod assembly sleeve (33); in step S5, the base plate (80) is installed on the bottom of the valve seat (10). The base plate (80) is provided with a base plate threaded hole. The cylinder cover (30), the cylinder body (20) and the valve seat (10) are provided with through holes corresponding to the base plate threaded hole. A flat washer (93) and a spring washer (92) are installed at the through hole of the cylinder cover (30). The bolt (91) passes through the cylinder cover (30), the cylinder body (20) and the valve seat (10) in sequence and locks with the base plate threaded hole of the base plate (80).

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