Wafer non-dissolved film whole film removing apparatus

Abstract

The application discloses a wafer insoluble film whole film removing equipment and relates to the technical field of wafer insoluble film removing. The equipment comprises a groove main body, a soaking cavity is arranged in the internal cavity of the groove main body, flow guide grooves are arranged on the inner walls of the soaking cavity, a sliding seat is fixed at the center position of the bottom of the soaking cavity, a suction port is arranged at the center position of the sliding seat, a liquid discharge pipe is connected to the suction port, a sealing cover is arranged at the end of the liquid discharge pipe, a collecting filter screen is fixed to the inner wall of the sealing cover, reaction cavities are slidingly arranged at the top of the two sides of the sliding seat, flow guide plates are fixed to the two sides of the reaction cavities, flow guide ports are arranged on the surfaces of the flow guide plates, fixing seats are arranged on the side walls of the flow guide plates, moving seats are arranged on the side walls of the fixing seats, distance changing assemblies are arranged in the internal cavities of the moving seats, and placing assemblies are arranged on the outer walls of the moving seats. The flow guide plates, the fixing seats and the distance changing assemblies are arranged, so that the distance between the groups of wafers can be changed when the equipment completes the suction circulation of the chemical reagent, and the whole film removing effect and quality are improved.

Description

Technical Field

[0001] This invention relates to the field of wafer non-soluble film removal technology, specifically to a wafer non-soluble film whole-film removal device. Background Technology

[0002] A wafer is a disk-shaped semiconductor material made from high-purity silicon single crystals. After precision polishing, its surface flatness reaches the nanometer level. It is the core carrier for integrated circuit manufacturing. The wafer surface is equipped with billions of transistor structures, and its performance directly determines the chip's computing power and energy efficiency. In chip manufacturing, insoluble protective films such as photoresist, hard masks, or polymers used in the patterning process must be thoroughly removed. If residual film layers remain, it will lead to abnormal subsequent metal deposition or oxide layer growth, causing circuit short circuits or performance drift. Among the equipment for removing insoluble films from wafers, chemical reagent immersion equipment is commonly used. This equipment is usually equipped with a corrosion-resistant tank to hold specific chemical reagents. By utilizing the chemical reaction between the reagents and the film material, the film layer is dissolved or peeled off, achieving the goal of efficient and clean removal. A circulation system is also set up to continuously circulate the chemical reagents for removing insoluble films within the tank, improving removal efficiency.

[0003] In existing wafer non-dissolving film removal equipment, the wafer placement device often adopts a dense arrangement design in pursuit of high efficiency. Although this arrangement increases the throughput per batch, after the entire film is removed, the film detached from the wafer will float in the equipment tank. Due to the dense arrangement of the wafers, the gaps between the wafers are very narrow, which restricts the flow of the entire film in the tank. This is not conducive to the smooth floating or discharge of the entire film, and it is easy for the entire film to get stuck in the gaps between wafers, the corners of the device, and other areas, forming dead corners. This affects the wafer film removal effect, and some films may not be effectively removed, increasing the risk of wafer contamination and reducing chip yield.

[0004] To address the aforementioned issues, innovative design based on existing methods is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer non-dissolving film removal device to solve the problem mentioned in the background art where the entire film floats in the tank after removal, which may get stuck in areas such as wafer gaps and device corners, forming dead corners and affecting the wafer film removal effect. The technical solution of this invention addresses the problem that the existing technical solutions are too simplistic and provides a solution that is significantly different from the existing technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a wafer non-dissolving film removal device, comprising a tank body, an immersion chamber installed in the cavity inside the tank body, guide grooves opened on both sides of the inner wall of the immersion chamber, a sliding seat fixed at the center of the bottom of the immersion chamber, a suction port opened through the center of the sliding seat, a drain pipe connected to the suction port, a sealing cap installed at the end of the drain pipe, a collection filter screen fixed on the inner wall of the sealing cap, reaction chambers slidably installed on both sides of the top of the sliding seat, guide plates fixed on both sides of the reaction chamber, multiple sets of guide ports opened through the surface of the guide plates, a fixed seat installed on the side wall of the guide plate, multiple sets of movable seats slidably installed on the side wall of the fixed seat, a variable pitch component provided in the cavity inside the movable seat, and a placement component provided on the outer wall of the movable seat;

[0007] The pitch-changing assembly includes a movable plate that is slidably installed in the cavity of the movable seat. The outer wall of the movable plate is provided with multiple sets of limiting grooves corresponding to the movable seat. A limiting block is fixed in the cavity of the inner wall of the movable seat. The limiting block slides in the limiting groove. Floating plates are symmetrically fixed on both sides of the outer wall of the movable plate.

[0008] Preferably, the drain pipe is threadedly connected to the sealing cap, and the drain pipe and the collecting filter screen are designed at an angle.

[0009] Preferably, the position of the guide plate corresponds to the position of the guide groove, and the cross-section of the guide port is designed to be inclined towards the inside of the reaction chamber.

[0010] Preferably, the multiple sets of limiting grooves are arranged in an outwardly inclined fan shape, with the limiting groove at the center of the moving plate as the reference.

[0011] Preferably, the placement assembly includes a placement seat slidably mounted on the outer wall of the movable seat, a placement groove is provided on the side wall of the placement seat, a rotating block is rotatably mounted on the inner wall of the placement groove, a first oil chamber is provided at the bottom of the placement seat, a first piston rod is slidably mounted on the inner wall of the first oil chamber, and a second oil chamber is provided at the bottom of the movable seat, a second piston rod is slidably mounted on the inner wall of the second oil chamber.

[0012] Preferably, the placement seat has a trapezoidal cross-section with a rounded transition, and the rotating block has an "L"-shaped design corresponding to the placement slot.

[0013] Preferably, the vertical end of the rotating block is in close contact with the inner wall of the placement groove, and the other end of the rotating block is away from the inner wall of the placement groove.

[0014] Preferably, the bottom end of the rotating block is provided with a sliding groove, and the protruding end of the first piston rod is rotatably connected to a protrusion, which slides within the sliding groove at the bottom end of the rotating block.

[0015] Preferably, the second oil chamber is located below the placement seat, the extended end of the second piston rod is fixedly connected to the bottom of the placement seat, and the first oil chamber and the second oil chamber are in communication with each other.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. This invention, through the design of a guide plate, a fixed seat, and a variable pitch assembly, enables multiple sets of wafers to dynamically change their spacing during the chemical reagent suction cycle, thereby improving the overall film removal effect and quality. The flow of the chemical reagent drives the float plate to move. As the float plate moves, the limiting groove squeezes the limiting block, guiding the moving seat to slide along the limiting groove on the outer wall of the fixed seat, thus changing the spacing between the multiple closely arranged wafers. This facilitates the effective dissolution and removal of residual film in the gaps by the flow of the chemical reagent, avoiding film accumulation caused by static dead corners.

[0018] 2. This invention, through its placement components, enables the equipment to adapt to 6-inch or 8-inch wafers, adjusting the placement seat position to keep the wafer in the optimal working position. When the wafer enters the placement seat along the placement groove, it squeezes the rotating block to make it rotate. The bottom end of the rotating block gradually squeezes the first piston rod, which is connected to the first oil chamber. When it is squeezed, it pushes the oil from the first oil chamber into the second oil chamber, pushing the second piston rod outward, thereby pushing the placement seat. The position is adaptively adjusted according to the wafer size, ensuring that wafers of different sizes can be in the optimal working position. The flexible buffering characteristics of hydraulic transmission avoid the rigid impact of traditional mechanical adjustment, effectively reducing the risk of wafer edge breakage and effectively improving processing accuracy and product quality.

[0019] 3. This invention, through the setting of an immersion chamber, a guide channel, a sliding seat, and a reaction chamber, rinses the wafer placed inside the reaction chamber, improving the overall film removal effect. By utilizing the movement of the reaction chamber, combined with the squeezing of chemical reagents by the inner wall of the immersion chamber, the chemical reagents are pressurized and flow along the guide channel, backflush into the guide port opened on the outer wall of the guide plate, rinsing the wafer placed inside the reaction chamber. This enhances the ability to scour residual film and impurities on the wafer surface, improves the working effect, and ensures the uniformity and efficiency of the film removal work. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0021] Figure 2 This is a three-dimensional structural cross-sectional view of the present invention from one perspective;

[0022] Figure 3 This is a three-dimensional structural cross-sectional view of the present invention from another perspective;

[0023] Figure 4 For the present invention Figure 3 Enlarged structural diagram at point A in the middle;

[0024] Figure 5 This is a three-dimensional sectional view of the soaking chamber of the present invention;

[0025] Figure 6 This is a three-dimensional structural diagram of the placement component and the pitch-changing component of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of the movable plate of the present invention;

[0027] Figure 8 This is a schematic diagram of the movable seat and placement seat structure of the present invention;

[0028] Figure 9 This is a three-dimensional structural cross-sectional view of the movable seat and placement seat of the present invention.

[0029] In the diagram: 1. Tank body; 2. Immersion chamber; 201. Guide channel; 202. Sliding seat; 203. Suction port; 3. Drain pipe; 301. Sealing cover; 302. Collection filter; 4. Reaction chamber; 5. Guide plate; 501. Guide port; 502. Fixed seat; 503. Moving plate; 504. Limiting channel; 505. Float plate; 6. Moving seat; 601. Placement seat; 602. Placement channel; 603. Rotating block; 604. Limiting block; 7. First oil chamber; 701. First piston rod; 702. Second oil chamber; 703. Second piston rod. Detailed Implementation

[0030] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figures 1-9This invention provides a technical solution: a wafer insoluble film removal device, comprising a tank body 1, an immersion chamber 2 installed in the internal cavity of the tank body 1, guide grooves 201 formed on both sides of the inner wall of the immersion chamber 2, a sliding seat 202 fixed at the center of the bottom of the immersion chamber 2, a suction port 203 extending through the center of the sliding seat 202, a drain pipe 3 connected to the suction port 203, a sealing cap 301 installed at the end of the drain pipe 3, a collection filter 302 fixed on the inner wall of the sealing cap 301, a reaction chamber 4 slidably installed on both sides of the top of the sliding seat 202, guide plates 5 fixed on both sides of the reaction chamber 4, and multiple sets of guide ports 501 extending through the surface of the guide plates 5. A fixed seat 502 is installed on the side wall of the guide plate 5. Multiple sets of movable seats 6 are slidably installed on the side wall of the fixed seat 502. A variable pitch component is set in the internal cavity of the movable seat 6, and a placement component is set on the outer wall of the movable seat 6. The chemical reagents guided from the guide channel 201 can be rinsed in all directions and at multiple angles through multiple guide ports 501, effectively removing residual film layers and impurities, and avoiding cleaning dead corners. The drain pipe 3 provides a channel for the circulation and discharge of chemical reagents. The collection filter 302 on the inner wall of the sealing cover 301 can intercept and collect impurities, insoluble film fragments and other substances in the chemical reagents during the discharge process, improving the working efficiency of the equipment.

[0032] The variable pitch assembly includes a movable plate 503 slidably installed in the cavity of the movable seat 6. The outer wall of the movable plate 503 has multiple sets of limiting grooves 504 corresponding to the movable seat 6. Limiting blocks 604 are fixed in the cavity of the inner wall of the movable seat 6 and slide within the limiting grooves 504. Floating plates 505 are symmetrically fixed on both sides of the outer wall of the movable plate 503. Driven by hydrodynamics, it does not require an additional power source, simplifying the structure of the equipment, reducing energy consumption and cost. Changing the gap between the multiple sets of wafers placed on the assembly facilitates the effective dissolution and removal of residual film by chemical reagents, avoids film accumulation caused by static dead corners, and improves the overall film removal effect and quality.

[0033] In one embodiment of the present invention, the drain pipe 3 is threadedly connected to the sealing cap 301, and the drain pipe 3 and the collecting filter screen 302 are designed at an angle. The threaded connection makes the connection between the sealing cap 301 and the drain pipe 3 tight and stable, effectively preventing leakage of chemical reagents during operation, and facilitating disassembly and installation. The angled collecting filter screen 302 allows the intercepted insoluble membrane fragments, impurities and other solid substances to slide down to the bottom of the collecting filter screen 302 under the action of gravity and collect, which is convenient for centralized cleaning.

[0034] In one embodiment of the present invention, the position of the guide plate 5 corresponds to the position of the guide groove 201, and the cross section of the guide port 501 is designed to be inclined towards the inside of the reaction chamber 4. The positions of the guide plate 5 and the guide groove 201 are precisely corresponding to form a continuous fluid channel. The reaction chamber 4 is close to the inner wall of the soaking chamber 2. When the chemical reagent is squeezed, the chemical reagent can be smoothly guided to impact the guide plate 5. The inclined design of the guide port 501 does not hinder the squeezed chemical reagent from entering the reaction chamber 4, but also provides a basis for subsequent suction work, so that the circulation system can first suction the liquid inside the reaction chamber 4.

[0035] As one embodiment of the present invention, multiple sets of limiting grooves 504 are arranged in an outward inclined fan shape with the limiting groove 504 at the center of the moving plate 503 as a reference. The inclined limiting grooves 504 form a guide structure, providing a stable foundation for the variable pitch movement of the moving seat 6 and preventing the moving seat 6 from shaking or vibrating.

[0036] In one embodiment of the present invention, the placement assembly includes a placement seat 601 slidably mounted on the outer wall of a movable seat 6, a placement groove 602 formed on the side wall of the placement seat 601, a rotating block 603 rotatably mounted on the inner wall of the placement groove 602, a first oil chamber 7 provided at the bottom of the placement seat 601, a first piston rod 701 slidably mounted on the inner wall of the first oil chamber 7, and a second oil chamber 702 provided at the bottom of the movable seat 6, a second piston rod 703 slidably mounted on the inner wall of the second oil chamber 702. When the wafer is placed into the placement groove 602, the outer wall of the wafer presses against the rotating block. Rotating block 603 causes it to rotate, and after rotating, it squeezes the first piston rod 701, causing the oil in the first oil chamber 7 to enter the second oil chamber 702, pushing the second piston rod 703, thereby pushing the placement seat 601 to move upward. In this way, the height of the placement seat 601 can be adaptively adjusted according to the size of the wafer, ensuring that wafers of different sizes can be in the optimal working position, improving the compatibility and adaptability of the equipment to wafers of different specifications. The flexible buffering characteristics of hydraulic transmission avoid the rigid impact of traditional mechanical adjustment, and are not prone to shaking or displacement.

[0037] As one embodiment of the present invention, the placement seat 601 has a trapezoidal cross-section with a rounded transition, and the rotating block 603 has an "L"-shaped design corresponding to the placement groove 602. The trapezoidal structure makes the placement seat 601 wide at the bottom and narrow at the top, which fits the circular outline of the wafer and forms a stable support shape. When carrying the wafer, it can distribute the force and avoid the wafer tilting or slipping due to instability of the center of gravity. The "L"-shaped rotating block 603 can effectively transmit the pressure applied by the wafer to the first piston rod 701, thereby better adapting to wafers of different sizes and improving the accuracy and reliability of the equipment.

[0038] In one embodiment of the present invention, the vertical end of the rotating block 603 is in close contact with the inner wall of the placement groove 602, and the other end of the rotating block 603 is away from the inner wall of the placement groove 602. When the wafer is placed along the placement groove 602, even a small displacement or pressure change can quickly trigger the rotation of the rotating block 603, which improves the working efficiency and processing speed of the equipment. The bottom end of the rotating block 603 extends out of the inner wall of the placement groove 602, providing sufficient space for its contact and action with the first piston rod 701. When the rotating block 603 rotates under the pressure of the wafer, the bottom end can smoothly and effectively squeeze the first piston rod 701, accurately transmitting the external force generated by the wafer placement to the first piston rod 701, thereby pushing the oil to flow between the first oil chamber 7 and the second oil chamber 702, realizing the adjustment of the position of the placement seat 601, and ensuring the smoothness of the force transmission process.

[0039] In one embodiment of the present invention, a groove is provided at the bottom end of the rotating block 603, and a protrusion is rotatably connected to the protruding end of the first piston rod 701. The protrusion slides within the groove at the bottom end of the rotating block 603, which is beneficial for the rotating block 603 to directly and efficiently transmit force to the first piston rod 701 when rotating.

[0040] In one embodiment of the present invention, the second oil chamber 702 is located below the placement seat 601, and the extended end of the second piston rod 703 is fixedly connected to the bottom of the placement seat 601. The first oil chamber 7 and the second oil chamber 702 are interconnected. The second oil chamber 702 is located below the placement seat 601, providing a stable support structure for the placement seat 601. When the oil in the second oil chamber 702 increases, it will push the second piston rod 703 to move upward, thereby causing the placement seat 601 to rise. This allows the device to adaptively adjust the height of the placement seat 601 according to the size of the wafer by the flow of oil between the two chambers, ensuring that wafers of different sizes can be in the optimal working position.

[0041] Working principle: When using this wafer non-dissolving film removal equipment, the operator first places the wafer smoothly between the two placement seats 601 along the placement groove 602. During the wafer installation process, the outer wall of the wafer will come into contact with the rotating block 603 and apply pressure to it. The rotating block 603 rotates under pressure. As the rotating block 603 continues to rotate, since the first piston rod 701 is rotatably connected to the protrusion, the protrusion slides in the sliding groove at the bottom of the rotating block 603. The rotating block 603 squeezes and pushes the first piston rod 701, causing the first piston rod 701 to move downward. The oil enters the second oil chamber 702 through the first oil chamber 7, pushing the second piston rod 703. Since the protruding end of the second piston rod 703 is fixedly connected to the bottom of the moving seat 6, the upward movement of the second piston rod 703 drives the placement seat 601 to move upward. The height of the placement seat 601 is adaptively adjusted according to the size of the wafer to ensure that wafers of different sizes can be in the optimal working position.

[0042] After placing the wafer and adjusting the height of the placement seat 601, chemical reagents are added to the equipment for immersion and film removal. During immersion, the equipment's circulation system draws and circulates the chemical reagents through the suction port 203 at the center of the sliding seat 202. As the chemical reagents circulate, the resulting force pushes the float 505 downwards. Simultaneously, the float 505 moves the moving plate 503 downwards. The limiting groove 504 on the outer wall of the moving plate 503 presses against the limiting block 604. Due to multiple... The limiting grooves 504 are based on the limiting grooves 504 at the center of the moving plate 503 and are distributed in an outward inclined fan shape. The moving seat 6 is slidably installed on the outer wall of the fixed seat 502. As the limiting block 604 is pressed, the moving seat 6 moves horizontally along the limiting grooves 504. Multiple sets of moving seats 6 move synchronously with varying pitch, changing the gap between the wafers installed in the multiple sets of placement seats 601, providing space for the flow of chemical reagents, which is conducive to the effective dissolution of chemical reagents and removal of the film residue in the gaps, avoiding film accumulation caused by static dead corners.

[0043] While the immersion film removal process is underway, the reaction chamber 4, driven by the motor, reciprocates linearly along the sliding seat 202. When the reaction chamber 4 approaches the inner wall of the immersion chamber 2, it exerts a squeezing effect on the chemical reagents in the immersion chamber 2, causing the chemical reagents to flow along the guide channel 201. Guided by the guide channel 201, the chemical reagents impact the guide plate 5 and are sprayed onto the wafer surface through the guide port 501, rinsing the wafer and enhancing the ability to flush away residual film and impurities on the wafer surface, thereby improving the overall film removal effect.

[0044] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate orientations or positional relationships based on the accompanying drawings, and are used only for ease of description and simplification, not to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wafer non-soluble film removal device, comprising a tank body (1), characterized in that: The main body (1) of the tank has an internal cavity in which a soaking chamber (2) is installed. A guide groove (201) is provided on both sides of the inner wall of the soaking chamber (2). A sliding seat (202) is fixed at the center of the bottom of the soaking chamber (2). A suction port (203) is provided through the center of the sliding seat (202). The suction port (203) is connected to a drain pipe (3). A sealing cap (301) is installed at the end of the drain pipe (3). A collection filter is fixed to the inner wall of the sealing cap (301). 302), the top two sides of the sliding seat (202) are slidably installed with reaction chambers (4), the two sides of the reaction chambers (4) are fixed with guide plates (5), the surface of the guide plates (5) is provided with multiple sets of guide ports (501), the side wall of the guide plates (5) is installed with a fixed seat (502), the side wall of the fixed seat (502) is slidably installed with multiple sets of movable seats (6), the internal cavity of the movable seat (6) is provided with a pitch component, and the outer wall of the movable seat (6) is provided with a placement component; The variable pitch assembly includes a movable plate (503) slidably installed in the cavity of the movable seat (6). The outer wall of the movable plate (503) is provided with multiple sets of limiting grooves (504) corresponding to the movable seat (6). A limiting block (604) is fixed in the cavity of the inner wall of the movable seat (6). The limiting block (604) slides in the limiting groove (504) and floating plates (505) are symmetrically fixed on both sides of the outer wall of the movable plate (503).

2. The wafer insoluble film removal equipment according to claim 1, characterized in that: The drain pipe (3) is threadedly connected to the sealing cap (301), and the drain pipe (3) and the collecting filter (302) are designed at an angle.

3. The wafer insoluble film removal equipment according to claim 2, characterized in that: The position of the guide plate (5) corresponds to the position of the guide groove (201), and the cross section of the guide port (501) is designed to be inclined towards the inside of the reaction chamber (4).

4. The wafer insoluble film removal equipment according to claim 3, characterized in that: The multiple sets of limiting grooves (504) are arranged in an outward inclined fan shape with the limiting groove (504) at the center of the moving plate (503) as the reference.

5. The wafer insoluble film removal equipment according to claim 4, characterized in that: The placement assembly includes a placement seat (601) slidably mounted on the outer wall of a movable seat (6), a placement groove (602) provided on the side wall of the placement seat (601), a rotating block (603) rotatably mounted on the inner wall of the placement groove (602), a first oil chamber (7) provided at the bottom of the placement seat (601), a first piston rod (701) slidably mounted on the inner wall of the first oil chamber (7), and a second oil chamber (702) provided at the bottom of the movable seat (6), a second piston rod (703) slidably mounted on the inner wall of the second oil chamber (702).

6. The wafer insoluble film removal equipment according to claim 5, characterized in that: The placement seat (601) has a trapezoidal cross-section with a rounded transition, and the rotating block (603) has an "L"-shaped design corresponding to the placement groove (602).

7. The wafer insoluble film removal equipment according to claim 6, characterized in that: The vertical end of the rotating block (603) is in close contact with the inner wall of the placement groove (602), and the other end of the rotating block (603) is away from the inner wall of the placement groove (602).

8. The wafer insoluble film removal equipment according to claim 7, characterized in that: The bottom end of the rotating block (603) is provided with a sliding groove, and the protruding end of the first piston rod (701) is rotatably connected to a protrusion, which slides within the sliding groove at the bottom end of the rotating block (603).

9. The wafer insoluble film removal equipment according to claim 8, characterized in that: The second oil chamber (702) is located below the placement seat (601), and the extended end of the second piston rod (703) is fixedly connected to the bottom of the placement seat (601). The first oil chamber (7) and the second oil chamber (702) are in communication with each other.

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