Wafer positioning device for glue coating and developing machine

Abstract

The present invention belongs to the technical field of semiconductor integrated circuit manufacturing, and discloses a wafer positioning device for a coating and developing machine, including a base and a pillar, a mounting cylinder is installed on the top of the pillar, a wafer is arranged above the mounting cylinder, a No. 1 cavity and a No. 2 cavity are provided inside the mounting cylinder, and an air pressure hole connected to the No. 1 cavity is provided, and a telescopic rod is installed in the inner cavity of the No. 1 cavity. This device adopts a relatively gentle way to realize the positioning function of the wafer, by providing a supporting mechanism to support the wafer in advance, and using a rotator to rotate the outer surface of the supporting column, so that the roller realizes the synchronous function of self-rotation and revolution, and can rotate and adapt the displacement of the wafer in any direction. This design realizes the full rotation support of the roller to the bottom of the wafer, completely avoiding the sliding friction of the supporting component to the wafer due to the relative displacement during the positioning process, and greatly reducing the wear and damage of the wafer.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor integrated circuit manufacturing, and in particular relates to a wafer positioning device for a glue coating and developing machine. Background Art

[0002] Wafers are silicon chips used to make silicon semiconductor circuits. The original material is silicon. It is made by dissolving high-purity polycrystalline silicon and then adding silicon crystal seeds, which are then slowly pulled out to form cylindrical single crystal silicon. The silicon rods are formed into wafers after grinding, polishing and slicing. After the wafers are formed, they need to be coated with glue and developed. Gluing can evenly cover the surface of the silicon wafer with a layer of photoresist and ensure that the photoresist is firmly and evenly attached without bubbles. Development is to remove the photoresist coated on the surface of the silicon wafer according to the depth of the predetermined chip circuit pattern, so as to prepare for subsequent photolithography. When the coating and developing machine is working, a robotic arm is required to place the wafer on a tray or a device for supporting the wafer. In general, since the robot will wear out after long-term work and then produce deviations, the wafer needs to be positioned after it is placed; in the prior art, the more common ones are double-claw structures or positioning groove cavity structures, which use the wafer to abut against it and automatically return to its position under the action of external force. Although the positioning effect can be achieved, the wafer, as a relatively fragile and high-precision semiconductor material, cannot accept surface friction and circumferential rigid wear. The aforementioned positioning methods require that the wafer and the contact parts slide relative to each other, or bear a certain rigid pressure, which may cause potential rigid wear to the wafer, resulting in material waste and increased manufacturing costs. Therefore, it is urgent to solve this problem. Summary of the invention

[0003] The object of the present invention is to provide a wafer positioning device for a glue coating and developing machine to solve the problems raised in the above-mentioned background technology.

[0004] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a wafer positioning device for a glue coating and developing machine, comprising a base and a pillar, a mounting cylinder is installed on the top of the pillar, a wafer is arranged above the mounting cylinder, a first cavity and a second cavity are provided inside the mounting cylinder, and an air pressure hole connected with the first cavity is provided, a telescopic rod is installed in the inner cavity of the first cavity, a piston is installed at the telescopic end of the telescopic rod, a sealing ring is installed on the outer circumferential surface of the piston, a plurality of supporting mechanisms are fixedly installed on the top of the piston, a supporting ring is installed on the top of the mounting cylinder, a motor and a plurality of intermediate columns are installed at the bottom of the mounting cylinder, a fixed block is fixedly installed on the output shaft of the motor, a plurality of active rods are fixedly installed on the outer surface of the fixed block, a clamping column is fixedly connected to the top of the active rod, a rotating plate is rotatably installed on the outer surface of the intermediate column, an adapting groove is provided on the top of the rotating plate, the clamping column is adapted to be clamped in the adapting groove, a positioning cylinder is fixedly installed on the top of the rotating plate, a positioning column is provided on the internal movable sleeve of the positioning cylinder, and a rotating cylinder and a buffer sleeve are rotatably installed on the outer surface of the positioning column;

[0005] The support mechanism includes a fixed cylinder, the interior of the fixed cylinder is movably sleeved with a support column and a spring 1, the outer surface of the spring 1 is rotatably mounted with a rotator, the interior of the rotator is rotatably mounted with a roller, and the wafer is supported on the outer surface of the roller.

[0006] As a preferred solution of the present invention, a plurality of groups of No. 1 magnets corresponding to the positioning cylinders are fixedly installed on the top of the base, a second spring is movably sleeved inside the positioning cylinder, the positioning column is elastically supported in the positioning cylinder by the second spring, a No. 2 magnet is fixedly installed on the bottom end of the positioning column, and the No. 2 magnet passes downward through the rotating plate.

[0007] As a preferred solution of the present invention, two groups of limiting rings are fixedly installed on the top of the outer surface of the positioning column, the rotating drum is rotatably installed in the two groups of limiting rings, the buffer sleeve is made of hard rubber, and the top of the positioning column is lower than the bottom of the wafer at the lowest point.

[0008] As a preferred solution of the present invention, the No. 2 chamber and the No. 1 chamber are connected up and down, the inner diameter of the No. 2 chamber is smaller than the inner diameter of the No. 1 chamber, the piston is interference fit on the inner wall of the No. 1 chamber, and the top of the piston abuts against the top of the inner wall of the No. 1 chamber.

[0009] As a preferred solution of the present invention, the support ring is made of rubber and is fixed to the top of the mounting tube by gluing, and a gap is left between the bottom of the wafer and the top of the support ring.

[0010] As a preferred solution of the present invention, the axes of the No. 1 magnet and the No. 2 magnet coincide with each other at the initial position, and at the initial position: the centers of the motor, the middle column and the clamping column are collinear.

[0011] As a preferred solution of the present invention, the second spring is stretched downward by the positioning column to be in a stressed state, and when the second magnet is offset from the first magnet, the positioning column moves upward under the pulling force of the second spring.

[0012] As a preferred solution of the present invention, the axis of the roller is perpendicular to the axis of the support column, and can perform circular motion around the axis of the support column.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1. This device has been redesigned and adopts a gentler way to achieve the positioning function of the wafer. The wafer is pre-supported by a supporting mechanism. During the positioning process, when the buffer sleeve performs centripetal abutment positioning on the wafer, the wafer is rotationally supported by rollers. At the same time, the rotator is rotated on the outer surface of the support column to enable the roller to achieve the synchronous function of self-rotation and revolution, and can rotate and adapt to the displacement of the wafer in any direction. This design realizes the full rotation support of the roller on the bottom of the wafer, completely avoiding the sliding friction of the support component on the wafer due to the relative displacement during the positioning process, and greatly reducing the wear and damage of the wafer.

[0015] 2. This device uses magnet No. 1 and magnet No. 2 to make the positioning cylinder and the rotating plate in their original positions, and the magnetic attraction force is used to keep the positioning column, the limit ring, the rotating cylinder and the buffer sleeve at the lowest height below the bottom of the wafer. When the robot drives the wafer to be placed on the installation cylinder, the minimum height design of the positioning column can avoid it interfering with the route of the robot when transporting the wafer. When the rotating plate drives the No. 2 magnet and the positioning cylinder to rotate, the No. 1 magnet and the No. 2 magnet are staggered, and the magnetic attraction force disappears. The positioning column automatically resets upward under the action of spring No. 2 and performs the positioning operation. Compared with the prior art, this design has the advantages of low cost, simple structure and anti-interference.

[0016] 3. This device utilizes the rotating plate installed on the middle column to drive the positioning cylinder to rotate around the axis of the middle column under the rotation coordination of the active rod and the clamping column, thereby realizing the progressive abutment function of the buffer sleeve on the outer peripheral surface of the wafer, which is helpful for accurate positioning of the wafer. The axis of the middle column deviates from the motor. When the motor drives the active rod and the clamping column to rotate, the clamping column drives the rotating plate and the positioning cylinder to rotate, so that the positioning column drives the rotating cylinder and the buffer sleeve to gradually approach the outer peripheral surface of the wafer and abut against it to perform a synchronous positioning function. During this period, the buffer sleeve rotates and abuts against the wafer and rotates around the axis of the positioning column, effectively protecting the outer peripheral surface of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional schematic diagram of the structure of the present invention;

[0018] Figure 2 For the present invention Figure 1 A magnified schematic diagram of the structure at center A;

[0019] Figure 3 It is a front cutaway schematic diagram of the structure of the present invention;

[0020] Figure 4 It is a side cutaway schematic diagram of the structure of the present invention;

[0021] Figure 5 For the present invention Figure 4 A magnified schematic diagram of the structure at B in the middle;

[0022] Figure 6 For the present invention Figure 4 A magnified schematic diagram of the structure at C in the middle;

[0023] Figure 7 It is a schematic diagram of the top view of the structure of the present invention;

[0024] Figure 8 It is a schematic diagram of the separation of the motor, the fixed block, the active rod, the clamping column, the intermediate column, the rotating plate, the No. 1 magnet, the positioning cylinder, the positioning column, the limiting ring, the rotating cylinder, the buffer sleeve, the spring No. 2 and the No. 2 magnet of the present invention;

[0025] Fig. 9 The figure is a schematic diagram of the separation of the telescopic rod, the piston, the sealing ring and the supporting mechanism of the present invention.

[0026] In the figure: 1. base; 2. pillar; 3. mounting cylinder; 31. cavity No. 1; 32. cavity No. 2; 4. wafer; 5. air pressure hole; 6. telescopic rod; 7. piston; 8. sealing ring; 9. supporting mechanism; 91. fixing cylinder; 92. supporting column; 93. spring No. 1; 94. rotator; 95. roller; 10. supporting ring; 11. motor; 12. fixing block; 13. active rod; 14. clamping column; 15. intermediate column; 16. rotating plate; 17. adapter groove; 18. magnet No. 1; 19. positioning cylinder; 20. positioning column; 21. limiting ring; 22. rotating cylinder; 23. buffer sleeve; 24. spring No. 2; 25. magnet No. 2. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] like Figures 1 to 9 As shown, an embodiment of the present invention provides a wafer positioning device for a glue coating and developing machine, comprising a base 1 and a pillar 2, a mounting cylinder 3 is installed on the top of the pillar 2, a wafer 4 is arranged above the mounting cylinder 3, a first cavity 31 and a second cavity 32 are arranged inside the mounting cylinder 3, and an air pressure hole 5 connected with the first cavity 31 is opened, a telescopic rod 6 is installed in the inner cavity of the first cavity 31, a piston 7 is installed at the telescopic end of the telescopic rod 6, a sealing ring 8 is installed on the outer circumferential surface of the piston 7, a plurality of supporting mechanisms 9 are fixedly installed on the top of the piston 7, a supporting ring 10 is installed on the top of the mounting cylinder 3, and the mounting cylinder 3 is provided with a plurality of supporting mechanisms 9. The bottom is provided with a motor 11 and multiple groups of intermediate columns 15, the output shaft of the motor 11 is fixedly provided with a fixed block 12, the outer surface of the fixed block 12 is fixedly provided with multiple groups of active rods 13, the top of the active rod 13 is fixedly connected with a clamping column 14, the outer surface of the intermediate column 15 is rotatably provided with a rotating plate 16, the top of the rotating plate 16 is provided with an adapting groove 17, the clamping column 14 is adapted to be engaged in the adapting groove 17, the top of the rotating plate 16 is fixedly provided with a positioning cylinder 19, the internal movable sleeve of the positioning cylinder 19 is provided with a positioning column 20, the outer surface of the positioning column 20 is rotatably provided with a rotating cylinder 22 and a buffer sleeve 23;

[0029] The support mechanism 9 includes a fixed cylinder 91, the interior of the fixed cylinder 91 is movably sleeved with a support column 92 and a spring 93, the outer surface of the spring 93 is rotatably mounted with a rotator 94, the interior of the rotator 94 is rotatably mounted with a roller 95, and the wafer 4 is supported on the outer surface of the roller 95;

[0030] The device has been redesigned to achieve the positioning function of the wafer 4 in a gentler manner. The wafer 4 is pre-supported by a supporting mechanism 9. During positioning, when the buffer sleeve 23 performs centripetal abutment positioning on the wafer 4, the wafer 4 is rotationally supported by the roller 95. At the same time, the rotator 94 is rotated on the outer surface of the support column 92 to enable the roller 95 to achieve the synchronous function of self-rotation and revolution, and can rotationally adapt to the displacement of the wafer 4 in any direction. This design achieves full rotational support of the bottom of the wafer 4 by the roller 95, completely avoiding the sliding friction of the support component on the wafer 4 due to the relative displacement during the positioning process, and greatly reducing the wear and damage of the wafer 4.

[0031] Among them, multiple groups of No. 1 magnets 18 corresponding to the positioning cylinders 19 are fixedly installed on the top of the base 1, and a second spring 24 is movably sleeved inside the positioning cylinder 19. The positioning column 20 is elastically supported in the positioning cylinder 19 by the second spring 24. A second magnet 25 is fixedly installed on the bottom end of the positioning column 20, and the second magnet 25 passes through the rotating plate 16 downward;

[0032] The device utilizes magnet No. 1 18 and magnet No. 2 25 to keep the positioning cylinder 19 and rotating plate 16 in their original positions, and maintains the positioning column 20, the limit ring 21, the rotating cylinder 22 and the buffer sleeve 23 at the lowest height below the bottom of the wafer 4 through magnetic attraction. When the robot drives the wafer 4 to be placed on the mounting cylinder 3, the lowest height design of the positioning column 20 can avoid interference with the route of the robot when transporting the wafer 4. When the rotating plate 16 drives the magnet No. 2 25 and the positioning cylinder 19 to rotate, the magnet No. 1 18 is staggered with the magnet No. 2 25, and the magnetic attraction disappears. The positioning column 20 automatically resets upward under the action of spring No. 2 24 and performs the positioning operation. Compared with the prior art, the present design has the advantages of low cost, simple structure and interference prevention.

[0033] Among them, two groups of limiting rings 21 are fixedly installed on the top of the outer surface of the positioning column 20, and the rotating drum 22 is rotatably installed in the two groups of limiting rings 21. The buffer sleeve 23 is made of hard rubber. The top of the positioning column 20 is lower than the bottom of the wafer 4 when it is at the lowest point;

[0034] The device utilizes the intermediate column 15 to rotate and install a rotating plate 16, and drives the positioning cylinder 19 to rotate around the axis of the intermediate column 15 under the rotation cooperation of the active rod 13 and the clamping column 14, thereby realizing the progressive abutment function of the buffer sleeve 23 on the outer peripheral surface of the wafer 4, which is helpful for accurately positioning the wafer 4. The axis of the intermediate column 15 deviates from the motor 11. When the motor 11 drives the active rod 13 and the clamping column 14 to rotate, the clamping column 14 drives the rotating plate 16 and the positioning cylinder 19 to rotate, so that the positioning column 20 drives the rotating cylinder 22 and the buffer sleeve 23 to gradually approach the outer peripheral surface of the wafer 4 and abut against it, and perform a synchronous positioning function. During this period, the buffer sleeve 23 rotates and abuts against the wafer 4, and rotates around the axis of the positioning column 20, thereby effectively protecting the outer peripheral surface of the wafer 4.

[0035] The second chamber 32 and the first chamber 31 are connected vertically, the inner diameter of the second chamber 32 is smaller than the inner diameter of the first chamber 31, the piston 7 is arranged on the inner wall of the first chamber 31 in an interference fit, and the top of the piston 7 abuts against the top of the inner wall of the first chamber 31;

[0036] Cavity No. 1 31 is used to place the telescopic rod 6 and the piston 7. After the supporting mechanism 9 completes the supporting and positioning operation on the wafer 4, the telescopic rod 6 drives the piston 7 and the sealing ring 8 to move downward, so that the wafer 4 can abut against the upper part of the supporting ring 10 to form a contact seal. During the continuous downward movement of the piston 7, a negative pressure will be generated in the inner cavities of cavity No. 1 31 and cavity No. 2 32, thereby automatically adsorbing and fixing the wafer 4 to facilitate subsequent processing.

[0037] The support ring 10 is made of rubber and is fixed to the top of the mounting tube 3 by gluing, and a gap is left between the bottom of the wafer 4 and the top of the support ring 10;

[0038] The support ring 10 is responsible for providing support for the wafer 4 and forming an edge seal to facilitate the downward movement of the piston 7 to generate a negative pressure fixed suction force on the wafer 4.

[0039] The axes of the first magnet 18 and the second magnet 25 coincide at the initial position. At the initial position, the centers of the motor 11, the middle column 15 and the clamping column 14 are collinear.

[0040] After the first magnet 18 and the second magnet 25 are aligned at the initial position, magnetic attraction is generated between them, and the positioning column 20 is pulled downward as a whole, so as to avoid interference with the route of the robot when transporting the wafer 4.

[0041] The second spring 24 is stretched downward by the positioning column 20 to be in a stressed state. When the second magnet 25 is offset from the first magnet 18, the positioning column 20 moves upward under the pulling force of the second spring 24.

[0042] When the positioning post 20 is pulled downward by the magnetic attraction force generated by the No. 1 magnet 18 and the No. 2 magnet 25, the spring 24 is stretched and generates an upward pulling force, the purpose of which is to pull the positioning post 20 upward and reset when the No. 2 magnet 25 is offset from the No. 1 magnet 18.

[0043] The axis of the roller 95 is perpendicular to the axis of the support column 92 and can perform circular motion around the axis of the support column 92;

[0044] The roller 95 rotates synchronously when in contact with the wafer 4, forming a rolling support for the wafer 4. When the displacement direction of the wafer 4 changes, the rotator 94 drives the roller 95 to revolve around the support column 92, performing all-round adaptive rotation, completely avoiding supporting sliding wear on the wafer 4.

[0045] Working principle:

[0046] When the device is working, the manipulator places the wafer 4 on the top of the mounting cylinder 3 and is supported by the supporting mechanism 9. The wafer 4 is supported by the roller 95, and the rotator 94 and the supporting column 92 are pressed downward, and the spring 1 93 is stretched to produce elastic support for the wafer 4. At this time, the piston 7 abuts against the top of the inner wall of the No. 1 chamber 31, and the wafer 4 does not contact the supporting ring 10;

[0047] Then, the motor 11 is started, and the fixed block 12, the active rod 13 and the clamping column 14 are driven to rotate clockwise. The clamping column 14 rotates inside the adapter groove 17, and drives the rotating plate 16 and the positioning cylinder 19 to rotate around the middle column 15. At this time, the second magnet 25 is driven to a position deviating from the axis of the first magnet 18, and the two are no longer magnetically connected. At this time, the positioning column 20 moves upward under the pulling force of the second spring 24, and drives the limit ring 21, the rotating cylinder 22 and the buffer sleeve 23 to move to the top of the wafer 4, so that the middle part of the buffer sleeve 23 is equivalent to the height of the wafer 4, and the positioning preparation is completed;

[0048] Then, the motor 11 continues to rotate, and the adapter groove 17 rotates around the middle column 15 under the action of the clamping column 14, and drives the positioning cylinder 19, the positioning column 20 and the buffer sleeve 23 to make a progressive movement gradually approaching the axis of the motor 11. The buffer sleeve 23 approaches the outer peripheral surface of the wafer 4 through rotation and abuts against it. The three groups of buffer sleeves 23 move at the same time and apply pressure to the outer peripheral surface of the wafer 4. The buffer sleeve 23 and the rotating cylinder 22 begin to rotate and abut against the wafer 4. The wafer 4 is driven and moves horizontally, driving the roller 95 to rotate. The roller 95 rotates on itself while being driven by the wafer 4, and revolves around the axis of the support column 92, realizing full rolling abutment between the roller 95 and the wafer 4.

[0049] Finally, when the three groups of buffer sleeves 23 abut against the outer peripheral surface of the wafer 4 at the same time, it is confirmed that the wafer 4 is positioned successfully, the motor 11 reverses, and drives the buffer sleeve 23 away from the wafer 4, starts the telescopic rod 6, and drives the piston 7 and the support mechanism 9 to move downward, so that the wafer 4 loses the support of the support mechanism 9 and falls on the support ring 10. At this time, the piston 7 continues to move downward, and generates negative pressure in the inner cavity of the No. 1 cavity 31 and the No. 2 cavity 32, and adsorbs and fixes the wafer 4, and finally completes the positioning operation.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wafer positioning device for a coating and developing machine, comprising a base (1) and a support (2), a mounting tube (3) being mounted on the top of the support (2), a wafer (4) being arranged above the mounting tube (3), and characterized in that: The interior of the installation cylinder (3) is provided with a first chamber (31) and a second chamber (32), and is provided with an air pressure hole (5) connected to the first chamber (31); a telescopic rod (6) is installed in the inner cavity of the first chamber (31); a piston (7) is installed at the telescopic end of the telescopic rod (6); a sealing ring (8) is installed on the outer peripheral surface of the piston (7); a plurality of supporting mechanisms (9) are fixedly installed on the top of the piston (7); a supporting ring (10) is installed on the top of the installation cylinder (3); a motor (11) and a plurality of intermediate columns (15) are installed at the bottom of the installation cylinder (3); an output shaft of the motor (11) is fixedly installed A fixed block (12) is provided, wherein a plurality of active rods (13) are fixedly mounted on the outer surface of the fixed block (12), a clamping column (14) is fixedly connected to the top of the active rod (13), a rotating plate (16) is rotatably mounted on the outer surface of the intermediate column (15), an adapting groove (17) is provided on the top of the rotating plate (16), the clamping column (14) is adapted to be clamped in the adapting groove (17), a positioning cylinder (19) is fixedly mounted on the top of the rotating plate (16), a positioning column (20) is movably sleeved inside the positioning cylinder (19), and a rotating cylinder (22) and a buffer sleeve (23) are rotatably mounted on the outer surface of the positioning column (20); The support mechanism (9) comprises a fixed cylinder (91), the interior of the fixed cylinder (91) being movably sleeved with a support column (92) and a spring (93), the outer surface of the spring (93) being rotatably mounted with a rotator (94), the interior of the rotator (94) being rotatably mounted with a roller (95), and the wafer (4) being supported on the outer surface of the roller (95); A plurality of groups of No. 1 magnets (18) corresponding to the positioning cylinders (19) are fixedly mounted on the top of the base (1), and a second spring (24) is movably sleeved inside the positioning cylinder (19). The positioning column (20) is elastically supported in the positioning cylinder (19) by the second spring (24). A second magnet (25) is fixedly mounted on the bottom end of the positioning column (20), and the second magnet (25) passes downward through the rotating plate (16). The axes of the No. 1 magnet (18) and the second magnet (25) coincide at the initial position. At the initial position, the centers of the motor (11), the intermediate column (15) and the clamping column (14) are collinear. The second spring (24) is stretched downward by the positioning column (20) to be in a stressed state. When the second magnet (25) is offset from the first magnet (18), the positioning column (20) moves upward under the pulling force of the second spring (24).

2. The wafer positioning device for a glue coating and developing machine according to claim 1, characterized in that: Two groups of limiting rings (21) are fixedly mounted on the top of the outer surface of the positioning column (20), the rotating drum (22) is rotatably mounted in the two groups of limiting rings (21), the buffer sleeve (23) is made of hard rubber, and the top of the positioning column (20) is lower than the bottom of the wafer (4) when at the lowest point.

3. The wafer positioning device for a coating and developing machine according to claim 2, characterized in that: The second chamber (32) and the first chamber (31) are connected vertically, the inner diameter of the second chamber (32) is smaller than the inner diameter of the first chamber (31), the piston (7) is arranged on the inner wall of the first chamber (31) in an interference fit, and the top end of the piston (7) abuts against the top of the inner wall of the first chamber (31).

4. The wafer positioning device for a coating and developing machine according to claim 3, characterized in that: The support ring (10) is made of rubber and is fixed to the top of the mounting cylinder (3) by gluing, and a gap is left between the bottom of the wafer (4) and the top of the support ring (10).

5. The wafer positioning device for a coating and developing machine according to claim 4, characterized in that: The axis of the roller (95) is perpendicular to the axis of the support column (92), and is capable of performing circular motion around the axis of the support column (92).

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