Control system and method of Bernoulli suction cup

Abstract

The invention provides a Bernoulli sucker control system and method.The Bernoulli sucker control system comprises a sucker, a pressure sensor, a displacement sensor, a supporting column, a chuck, a proportional valve and a controller, a main air cavity is formed in the sucker, and a plurality of main jet holes which are evenly distributed along the first circumference and communicate with the main air cavity are formed in the top of the sucker; the pressure sensor is arranged in the suction cup and extends into the main jet hole, the displacement sensor is arranged on the upper surface of the suction cup, the supporting column is fixed to the bottom of the suction cup and internally provided with a main air supply pipe communicated with the main air cavity and a main air inlet communicated with the main air supply pipe, and the chuck is arranged on the periphery of the supporting column in a sleeving mode and fixedly provided with a clamping pin surrounding the suction cup. The proportional valve is arranged on the main air supply pipe, the input end of the controller is connected with the pressure sensor and the displacement sensor, and the output end of the controller is connected with the proportional valve. The control system of the Bernoulli suction cup can monitor the suspension state of the wafer in real time, adjust the gas pressure in time, and ensure stable adsorption.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor integrated circuit manufacturing, and relates to a control system and method of a Bernoulli chuck. BACKGROUND

[0002] With the development of double-side cleaning process of semiconductor wafers, the fixing mode based on mechanical clamping is gradually eliminated. A Bernoulli chuck realizes non-contact suspension clamping of wafers by using the negative pressure difference generated by high-speed airflow between the wafer and the chuck. By optimizing the inclination angle of the nozzle of the chuck to 15°-30° and controlling the flow rate of the ejected gas to 5m / s to 15m / s, the chuck can maintain an adsorption pressure of 10Pa-50Pa, so that the suspension height of the wafer is stably maintained in the range of 50μm-200μm. Compared with mechanical clamping, this technology reduces the contact area by more than 98%, and realizes fixation only through edge positioning contacts, effectively avoiding the risk of surface damage.

[0003] However, the existing Bernoulli chuck has the following limitations: (1) It relies on fixed gas flow control, and uneven liquid distribution or airflow disturbance can easily cause local fluctuations of the wafer; (2) It cannot detect liquid distribution and airflow fluctuations in real time, and lacks dynamic response to pressure fluctuations; (3) The pressure adjustment of the ejected gas requires frequent manual intervention.

[0004] Therefore, how to provide a control system and method of a Bernoulli chuck to monitor the suspension state of the wafer in real time and adjust the pressure of the ejected gas in time to ensure the stability of the suspension height of the wafer has become an important problem to be solved by those skilled in the art.

[0005] It should be noted that the above introduction to the technical background is only to facilitate the clear and complete description of the technical scheme of the present application, and to facilitate the understanding of those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art merely because it is described in the background section of the present application. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a control system and method of a Bernoulli chuck to solve the problems of unstable suspension height of the wafer, inability to monitor the suspension state of the wafer in real time, and the need for manual frequent intervention to adjust the gas pressure in the prior art.

[0007] To achieve the above-mentioned purpose and other related purposes, the present application provides a control system of a Bernoulli chuck, comprising:

[0008] A suction cup, wherein a main air cavity is defined within the suction cup, the main air cavity comprising an annular portion and a connecting portion located at a top of the annular portion; a plurality of main injection holes are defined on the top of the suction cup and are evenly distributed along a first circumference; the main injection holes are connected to the annular portion through the connecting portion and are inclined toward an outer edge of the suction cup at a predetermined angle;

[0009] a pressure sensor and a displacement sensor, wherein the pressure sensor is disposed inside the suction cup, and a probe of the pressure sensor extends into the main injection hole, and the displacement sensor is disposed on the upper surface of the suction cup;

[0010] A support column is fixedly connected to the bottom of the suction cup, a main air supply pipe is provided inside the support column, the main air supply pipe is communicated with the annular portion, and a main air inlet is provided on the side wall of the support column, the main air inlet is communicated with the main air supply pipe;

[0011] A chuck is sleeved around the support column, and a clamping pin surrounding the suction cup is fixed on the chuck;

[0012] A proportional valve is provided on the main air supply pipe;

[0013] The controller includes an input end and an output end, wherein the input end is electrically connected to the pressure sensor and the displacement sensor, and the output end is electrically connected to the proportional valve.

[0014] Optionally, an emergency system is further included, the emergency system comprising:

[0015] An emergency air cavity is provided inside the suction cup and is isolated from the annular air cavity;

[0016] a plurality of emergency spray holes uniformly distributed on the top of the suction cup along the second circumference, the emergency spray holes being in communication with the emergency air cavity, and the distance between the emergency spray holes and the center of the suction cup being smaller than the distance between the main spray holes and the center of the suction cup;

[0017] An emergency air supply pipe is provided inside the support column and isolated from the main air supply pipe, and the emergency air supply pipe is communicated with the emergency air cavity;

[0018] An emergency air inlet is provided on the side wall of the support column and is isolated from the main air inlet, and the emergency air inlet is connected to the emergency air supply pipe;

[0019] The emergency valve is arranged on the emergency air supply pipe and is electrically connected to the output end of the controller.

[0020] Optionally, the distance between the outer edge of the emergency air cavity and the central axis of the suction cup is smaller than the distance between the outer edge of the annular portion of the main air cavity and the central axis of the suction cup.

[0021] Optionally, a protective groove is provided on the upper surface of the suction cup, the displacement sensor is arranged at the bottom of the protective groove, and the protective groove is located in the area surrounded by the second circumference.

[0022] Optionally, a bearing is installed between the chuck and the support column.

[0023] Optionally, the probe of the pressure sensor is wrapped with a sealing sleeve.

[0024] Optionally, there are multiple pressure sensors, a probe of each pressure sensor extends into one of the main injection holes, and the distance between any two adjacent pressure sensors is equal.

[0025] Optionally, the response time of the proportional valve is less than 20 ms.

[0026] The present invention also includes a control method for a Bernoulli suction cup, comprising at least the following steps:

[0027] Providing a control system for the Bernoulli suction cup described in any one of the above;

[0028] Adsorbing a wafer onto the suction cup, wherein the wafer is located within the positioning area surrounded by the clamping pins;

[0029] measuring the distance between the wafer and the suction cup;

[0030] The distance value is compared with a preset distance value, and the valve opening of the proportional valve is adjusted.

[0031] Optionally, the method further includes the following steps:

[0032] measuring the gas pressure value in the main injection hole;

[0033] Compare the gas pressure value with the preset gas pressure value and adjust the switch state of the emergency valve.

[0034] As described above, the control system of the Bernoulli suction cup of the present invention includes a suction cup, a pressure sensor, a displacement sensor, a support column, a chuck, a proportional valve and a controller, wherein a main air cavity is provided inside the suction cup, a plurality of main injection holes evenly distributed along a circle are provided on the top of the suction cup, the main injection holes are connected to the main air cavity and inclined toward the outer edge of the suction cup at a predetermined angle, the pressure sensor is arranged inside the suction cup, and the probe of the pressure sensor extends into the main injection hole, the displacement sensor is arranged on the upper surface of the suction cup, the support column is fixedly connected to the bottom of the suction cup, a main air supply pipe is provided inside the support column, the main air supply pipe is connected to the main air cavity, a main air inlet is provided on the side wall of the support column, the main air inlet is connected to the main air supply pipe, the chuck is sleeved on the support column, a clamping pin surrounding the suction cup is fixed on the chuck, the proportional valve is arranged on the main air supply pipe, and the controller includes an input end and an output end, the input end is electrically connected to the pressure sensor and the displacement sensor, and the output end is electrically connected to the proportional valve. The control system of the Bernoulli chuck of the present invention can monitor the suspension state of the wafer in real time, adjust the pressure of the injection gas in time, and ensure the stability of the wafer suspension. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Shown is a schematic structural diagram of the control system of the Bernoulli suction cup of the present invention.

[0036] Figure 2 Shown is a top view of the structure of the control system of the Bernoulli chuck of the present invention.

[0037] Figure 3 A diagram showing the working principle of the Bernoulli suction cup control system of the present invention.

[0038] Figure 4 Schematic diagram showing the installation location of the pressure sensor in the control system of the Bernoulli chuck of the present invention.

[0039] Description of Reference Numerals

[0040] 1 suction cup

[0041] 2 Main air cavity

[0042] 201 Ring

[0043] 202 connection

[0044] 3 Main injection holes

[0045] 4 Pressure sensor

[0046] 5 Displacement Sensor

[0047] 6 Support columns

[0048] 7 Main air supply pipe

[0049] 8 Main air intake

[0050] 9 Chuck

[0051] 10 Clamping pin

[0052] 11 Proportional valve

[0053] 12 Controller

[0054] 121 Input

[0055] 122 output

[0056] 13 bearings

[0057] 14 Emergency air chamber

[0058] 15 Emergency ejection hole

[0059] 16 Emergency gas supply pipe

[0060] 17 Emergency air intake

[0061] 18 Emergency valve

[0062] 19 protective groove

[0063] 20 wafers DETAILED DESCRIPTION

[0064] Bernoulli's principle states that along a streamline, the total mechanical energy of a fluid (the sum of pressure, kinetic, and gravitational potential energy) remains constant. Specifically, on the same horizontal surface, as the flow rate of a fluid increases, its pressure decreases. For example, if a gas is accelerated between two spaced balloons, the pressure between them will be lower than the pressure outside. This pressure difference will push the balloons toward each other.

[0065] Furthermore, Bernoulli's principle has a wide range of applications. For example, during takeoff, an airplane's wing is convex at the top and flat at the bottom. As the plane glides down the runway and accelerates, the air above the wing flows faster than the air below. According to Bernoulli's principle, the pressure above the wing is lower than the pressure below, creating an upward pressure difference—lift. This lift counteracts the weight of the aircraft, allowing the plane to take to the air.

[0066] There are mainly two types of control methods for existing Bernoulli suction cups. The first control method is an open-loop control method that uses a mechanical regulating valve in combination with a flow meter. The valve opening of the regulating valve is manually set, and the gas flow is monitored by the flow meter. It operates with fixed parameters and ejects a jet gas with a fixed gas pressure. The second control method is an open-loop control method that uses a proportional valve in combination with PLC program control. The flow curve of the jet gas is preset in advance, and the proportional valve is driven by the PLC program to adjust the valve opening according to a fixed logic, and ejects a jet gas that changes along the preset flow curve. However, both of the above methods are open-loop control, which requires frequent manual intervention, cannot respond to pressure fluctuations in real time (such as changes in air film pressure caused by wafer vibration), and lack closed-loop feedback. In addition, manual intervention also leads to adjustment lag.

[0067] In this regard, the present invention provides a control system and method for a Bernoulli chuck, which can monitor the suspension state of the wafer in real time, adjust the pressure of the injection gas in time, and ensure the stability of the wafer suspension height.

[0068] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0069] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

[0070] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0071] For example, when describing the embodiments of the present invention, schematic diagrams illustrating device structures may be partially enlarged for ease of explanation. These schematic diagrams are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0072] For convenience in description, spatially relative terms such as "beneath", "below", "lower", "under", "above", "upper" and the like can be used for the purpose of illustrating one element or feature's relationship to another element(s) or feature(s) as the devices are depicted in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0073] In the context of the present application, a structure described as being "on" another structure can include embodiments where the first and second structures are in direct contact, as well as embodiments where additional structures are interposed between the first and second structures such that the first and second structures are not in direct contact.

[0074] Needless to say, the diagrams provided in the embodiments are only schematic and intended to provide the basic understanding of the present application. In the diagrams, the shape, number, and size of the components are not intended to represent the actual shape, number, and size of the components in the application, and the actual shape, number, and size of the components in the application can be changed arbitrarily, and the layout of the components can be more complex.

[0075] Embodiment One

[0076] In this embodiment, a control system of a Bernoulli chuck is provided. Please refer to Figures 1 to 2 In which, Figure 1 The structure diagram of the control system of the Bernoulli chuck of the present application is shown, Figure 2The structure of the control system of the Bernoulli chuck of the present application is shown in the top view, which comprises a chuck 1, a pressure sensor 4, a displacement sensor 5, a support column 6, a chuck 9, a proportional valve 11 and a controller 12. The inside of the chuck 1 is provided with a main air cavity 2, which comprises an annular part 201 and a connecting part 202 on the top of the annular part 201. The top of the chuck 1 is provided with a plurality of main jet holes 3 uniformly distributed along the circle. The main jet holes 3 communicate with the annular part 201 through the connecting part 202 and are inclined to the outer edge of the chuck 1 at a predetermined angle. The pressure sensor 4 is arranged in the inside of the chuck 1, and the probe of the pressure sensor 4 extends into the main jet hole 3. The displacement sensor 5 is arranged on the upper surface of the chuck 1. The support column 6 is fixedly connected to the bottom of the chuck 1. The inside of the support column 6 is provided with a main air supply pipe 7, which communicates with the annular part 201. The side wall of the support column 6 is provided with a main air inlet 8, which communicates with the main air supply pipe 7. The chuck 9 is sleeved around the support column 6. The chuck 9 is fixedly provided with a clamping pin 10 surrounding the chuck 1. The proportional valve 11 is arranged on the main air supply pipe 7. The controller 12 comprises an input end 121 and an output end 122. The input end 121 is electrically connected with the pressure sensor 4 and the displacement sensor 5. The output end 122 is electrically connected with the proportional valve 11.

[0077] Specifically, the working process of the control system of the Bernoulli chuck is as follows:

[0078] First, the proportional valve 11 is opened. The proportional valve 11 maintains a fixed valve opening degree, so that the gas flows to the annular part 201 and the main jet hole 3 at a fixed speed. Please refer to Figure 3 When the gas is sprayed from the main jet hole 3 to the side of the wafer 20 close to the chuck 1, the gas pressure on this side will be less than the atmospheric pressure, while the gas on the other side of the wafer 20 maintains the atmospheric pressure. At this time, the pressure difference between the two sides of the wafer 20 generates a thrust on the wafer 20 (thrust = pressure difference × area of the wafer 20). When the thrust on the wafer 20 is equal to the gravity on the wafer 20, the wafer 20 will be stably adsorbed at a position with a fixed distance from the chuck 1 (i.e. a preset distance value). Therefore, the wafer 20 will be adsorbed by the chuck 1, and the wafer 20 is located in the positioning area surrounded by the clamping pin 10.

[0079] Subsequently, the displacement sensor 5 starts to detect the distance value between the wafer 20 and the chuck 1 in real time and transmits the distance value to the input end 121 of the controller 12. When the distance value is not equal to the preset distance value, the controller 12 sends an adjusting instruction to the proportional valve 11. Specifically, when the distance value is less than the preset distance value, the controller 12 sends a decreasing instruction to the proportional valve 11, and the proportional valve 11 decreases the valve opening degree, so that the gas flow rate ejected by the chuck 1 becomes smaller, thereby increasing the gas pressure on the side of the wafer 20 close to the chuck 1. This makes the wafer 20 move away from the chuck 1 to restore the preset distance. When the distance value is greater than the preset distance value, the controller 12 sends an increasing instruction to the proportional valve 11, and the proportional valve 11 increases the valve opening degree, so that the gas flow rate ejected by the chuck 1 becomes larger, thereby reducing the gas pressure on the side of the wafer 20 close to the chuck 1. This makes the wafer 20 move close to the chuck 1 to restore the preset distance.

[0080] Further, as can be seen from the working process of the control system of the Bernoulli chuck, the control system of the Bernoulli chuck forms a closed-loop control logic through the proportional valve 11, the displacement sensor 5 and the controller 12, avoiding manual intervention. When the wafer 20 fluctuates, the displacement sensor 5 and the controller 12 cooperate with each other to detect that the displacement of the wafer 20 has changed. The controller 12 then sends an adjusting instruction (increasing or decreasing) to the proportional valve 11 through internal logic judgment (i.e., judging the size relationship between the distance value of the wafer 20 and the preset distance value), and then adjusts the valve opening degree of the proportional valve 11, so as to quickly adjust the gas flow rate ejected by the main ejection hole 3, restore the wafer 20 to the original position, and realize the stable adsorption of the wafer 20.

[0081] It should be noted that the control system of the Bernoulli chuck is applied to the cleaning process of the wafer 20, and the fluctuation of the wafer 20 is usually caused by the cleaning liquid ejected by the cleaning machine. Specifically, when the cleaning liquid is ejected to the surface of the wafer 20 for cleaning, only when the ejection pressure of the cleaning liquid suddenly increases, the wafer 20 will fluctuate. This is because if the ejection pressure of the cleaning liquid suddenly decreases, the force balance of the wafer 20 will not be affected.

[0082] In addition, the displacement sensor 5 can detect the gas pressure value in the main jet hole 3 in real time and transmit the gas pressure value to the input end 121 of the controller 12. The change of the gas pressure value can reflect the change of the valve opening of the proportional valve 11, and further reflect the displacement change of the wafer 20 (i.e. the fluctuation of the wafer 20). Through the real-time detection of the displacement sensor 5, the controller 12 can draw the change value of the gas pressure, and the operator can intuitively observe the number of fluctuations of the wafer 20 through the change curve of the gas pressure value, and further optimize the process parameters, so as to further improve the stability of the wafer 20 adsorption.

[0083] As an example, please refer to Figures 1 to 2 The control system of the Bernoulli chuck further includes an emergency system, the emergency system includes an emergency gas cavity 14, a plurality of emergency jet holes 15, an emergency gas supply pipe 16, an emergency gas inlet 17 and an emergency valve 18. The emergency gas cavity 14 is arranged in the chuck 1 and is isolated from the annular gas cavity. The plurality of emergency jet holes 15 are uniformly distributed on the top of the chuck 1 along a second circumference. The emergency jet holes 15 are in communication with the emergency gas cavity 14, and the distance between the emergency jet holes 15 and the center of the chuck 1 is less than the distance between the main jet hole 3 and the center of the chuck 1. The emergency gas supply pipe 16 is arranged in the support column 6 and is isolated from the main gas supply pipe 7. The emergency gas supply pipe 16 is in communication with the emergency gas cavity 14. The emergency gas inlet 17 is arranged on the side wall of the support column 6 and is isolated from the main gas inlet 8. The emergency gas inlet 17 is in communication with the emergency gas supply pipe 16. The emergency valve 18 is arranged on the emergency gas supply pipe 16 and is electrically connected with the output end 122 of the controller 12.

[0084] Specifically, when the controller 12 sends a large instruction, if the pressure sensor 4 does not detect the change of the gas pressure in the main jet hole 3, it indicates that one or more of the proportional valve 11, the main gas supply pipe 7, the annular part 201 or the main jet hole 3 has failed. At this time, the controller 12 sends an emergency instruction to the emergency valve 18, so that the emergency valve 18 is switched from the closed state to the open state. The emergency gas is transmitted along the emergency gas supply pipe 16 to the emergency gas cavity 14, and then sprayed outward through the emergency jet hole 15, so as to solve the problem of out-of-control of the proportional valve 11 and help the wafer 20 to return to the original position, so as to ensure the stable adsorption of the wafer 20.

[0085] As an example, the distance between the outer edge of the emergency air cavity 14 and the central axis of the suction cup 1 is smaller than the distance between the outer edge of the annular portion 201 of the main air cavity 2 and the central axis of the suction cup 1. This is because the distance between the emergency injection hole 15 and the center of the suction cup 1 is smaller than the distance between the main injection hole 3 and the center of the suction cup 1. Setting the distance between the outer edge of the emergency air cavity 14 and the central axis of the suction cup 1 to be smaller than the distance between the outer edge of the annular portion 201 of the main air cavity 2 and the central axis of the suction cup 1 makes it easier to communicate with the main injection hole 3 and the annular portion 201, as well as with the emergency injection hole 15 and the emergency air cavity 14.

[0086] As an example, a protective groove 19 is provided on the upper surface of the suction cup 1, the displacement sensor 5 is arranged at the bottom of the protective groove 19, and the protective groove 19 is located in the area surrounded by the second circle, that is, the projection of the protective groove 19 in the vertical direction is located in the area surrounded by the multiple emergency injection holes 15. When the wafer 20 is adsorbed, various chips are provided on the side of the wafer 20 facing the suction cup 1. When the wafer 20 falls onto the suction cup 1, the existence of the protective groove 19 can prevent the chip from colliding with the suction cup 1, thereby protecting the chip on the wafer 20.

[0087] As an example, a bearing 13 is installed between the chuck 9 and the support column 6, so that the support column 6 can drive the suction cup 1 to rotate, and then drive the wafer 20 to rotate. After the cleaning process is completed, the suction cup 1 can remove the cleaning liquid attached to the wafer 20 by rotating the wafer 20.

[0088] As an example, the probe of the pressure sensor 4 is wrapped with a sealing sleeve to isolate the cleaning fluid and prevent the pressure sensor 4 from being corroded. Furthermore, in this embodiment, the connecting line between the pressure sensor 4 and the controller 12 is led out through the waterproof interface on the side wall of the nozzle hole.

[0089] As an example, the number of the pressure sensors 4 is multiple, and the probe of each pressure sensor 4 extends into one of the main injection holes 3, and the distance between any two adjacent pressure sensors 4 is equal, so as to achieve synchronous detection of multiple main injection holes 3, avoid the control system of the Bernoulli suction cup from generating erroneous judgments and instructions when one of the pressure sensors 4 fails, and ensure the normal operation of the control system of the Bernoulli suction cup. In this embodiment, please refer to Figure 4The number of the pressure sensors 4 is three, and they are installed in the main injection hole 3 at equal intervals. That is, the angle θ formed between the pressure sensor 4 and the line connecting the center of the suction cup 1 is 120°. In other embodiments, the number of the pressure sensors 4 can also be four, six or eight, corresponding to the angle θ of 90°, 60° or 45°.

[0090] As an example, the probe of the pressure sensor 4 is located in the same plane as the gas flow channel inside the main injection hole 3 , so as to ensure that the pressure sensor 4 directly senses the dynamic pressure of the injection gas flow.

[0091] As an example, the response time of the proportional valve 11 is less than 20ms, so as to ensure that the controller 12 regulates the flow rate of the injection gas and speeds up the correction of the position offset of the wafer 20, thereby meeting the demand for rapid correction of micron-level displacement of the wafer.

[0092] As an example, the gas sprayed by the suction cup 1 includes nitrogen, which has stable properties and is conducive to stable adsorption of the wafer 20.

[0093] The control system of the Bernoulli suction cup of the present invention is used in the wafer cleaning process. The system includes a suction cup, a pressure sensor, a displacement sensor, a support column, a chuck, a proportional valve and a controller. A closed-loop control logic composed of the proportional valve, the displacement sensor and the controller is constructed, so that the gas flow rate injected from the main injection hole can be quickly adjusted to restore the wafer to its original position, thereby achieving stable adsorption of the wafer and avoiding manual intervention. In addition, the system only requires displacement detection and proportional valve adjustment, with a simple structure and low cost.

[0094] Example 2

[0095] This embodiment provides a control method for a Bernoulli suction cup, comprising at least the following steps:

[0096] S1: Provide a control system for the Bernoulli suction cup described in Example 1.

[0097] S2: sucking a wafer onto the suction cup 1 , wherein the wafer 20 is located in the positioning area surrounded by the clamping pins 10 .

[0098] S3: Measure the distance between the wafer 20 and the suction cup 1 .

[0099] Specifically, the displacement sensor 5 detects the distance between the wafer 20 and the suction cup 1 in real time, and transmits the distance value to the input terminal 121 of the controller 12 .

[0100] S4: Compare the distance value with a preset distance value, and adjust the valve opening of the proportional valve 11.

[0101] Specifically, when the distance value is less than the preset distance value, the controller 12 sends a small instruction to the proportional valve 11, and the proportional valve 11 reduces the valve opening degree, so that the gas flow rate sprayed by the chuck 1 becomes smaller, thereby increasing the gas pressure on the side of the wafer 20 close to the chuck 1. This will make the wafer 20 move away from the chuck 1 to restore the preset distance. When the distance value is greater than the preset distance value, the controller 12 sends a large instruction to the proportional valve 11, and the proportional valve 11 increases the valve opening degree, so that the gas flow rate sprayed by the chuck 1 becomes larger, thereby reducing the gas pressure on the side of the wafer 20 close to the chuck 1. This will make the wafer 20 move close to the chuck 1 to restore the preset distance.

[0102] As an example, the control method of the Bernoulli chuck further comprises the following steps:

[0103] (1) Measure the gas pressure value in the main jet hole 3.

[0104] (2) Compare the gas pressure value with the preset gas pressure value, and adjust the on-off state of the emergency valve 18.

[0105] Specifically, after the controller 12 sends a large instruction, if the gas pressure value is always the same as the preset gas pressure value, it indicates that the gas flow rate sprayed by the chuck 1 is not adjusted, that is, one or more of the proportional valve 11, the main gas supply pipe 7, the annular part 201 or the main jet hole 3 has a fault. At this time, the controller 12 sends an emergency instruction to the emergency valve 18, so that the emergency valve 18 switches from the closed state to the open state, and the emergency gas is transmitted along the emergency gas supply pipe 7 to the emergency gas cavity 14, and then sprayed outwards through the emergency jet hole 3, so as to solve the problem of out-of-control of the proportional valve 11, help the wafer 20 to restore to the original position, and ensure the stable adsorption of the wafer 20.

[0106] The control method of the Bernoulli chuck of the present application can realize the stability of the wafer suspension state by detecting the position of the wafer in real time, adjusting the valve opening degree of the proportional valve, forming a closed loop control logic, thereby avoiding manual intervention and quickly eliminating the fluctuation of the wafer.

[0107] In summary, the control system of the Bernoulli chuck of the present application comprises a chuck, a pressure sensor, a displacement sensor, a support column, a chuck, a proportional valve and a controller, wherein the inside of the chuck is provided with a main air cavity, the top of the chuck is provided with a plurality of main jet holes which are uniformly distributed along a circle, the main jet holes are communicated with the main air cavity and are inclined to the outer edge of the chuck at a predetermined angle, the pressure sensor is arranged in the inside of the chuck, and the probe of the pressure sensor extends into the main jet hole, the displacement sensor is arranged on the upper surface of the chuck, the support column is fixedly connected to the bottom of the chuck, the inside of the support column is provided with a main gas supply pipe, the main gas supply pipe is communicated with the main air cavity, the sidewall of the support column is provided with a main air inlet, the main air inlet is communicated with the main gas supply pipe, the chuck is sleeved on the support column, the chuck is fixedly provided with a clamping pin which surrounds the chuck, the proportional valve is arranged on the main gas supply pipe, the controller comprises an input end and an output end, the input end is electrically connected with the pressure sensor and the displacement sensor, and the output end is electrically connected with the proportional valve. The control system of the Bernoulli chuck of the present application can monitor the suspension state of the wafer in real time, adjust the pressure of the jet gas in time, and ensure the stability of the wafer suspension. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has high industrial utilization value.

[0108] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A control system for a Bernoulli suction cup, characterized in that: include: A suction cup, wherein a main air cavity is defined within the suction cup, the main air cavity comprising an annular portion and a connecting portion located at a top of the annular portion; a plurality of main injection holes are defined on the top of the suction cup and are evenly distributed along a first circumference; the main injection holes are connected to the annular portion through the connecting portion and are inclined toward an outer edge of the suction cup at a predetermined angle; a pressure sensor and a displacement sensor, wherein the pressure sensor is disposed inside the suction cup, and a probe of the pressure sensor extends into the main injection hole, and the displacement sensor is disposed on the upper surface of the suction cup; A support column is fixedly connected to the bottom of the suction cup, a main air supply pipe is provided inside the support column, the main air supply pipe is communicated with the annular portion, and a main air inlet is provided on the side wall of the support column, the main air inlet is communicated with the main air supply pipe; A chuck is sleeved around the support column, and a clamping pin surrounding the suction cup is fixed on the chuck; A proportional valve is provided on the main air supply pipe; The controller includes an input end and an output end, wherein the input end is electrically connected to the pressure sensor and the displacement sensor, and the output end is electrically connected to the proportional valve.

2. The control system of the Bernoulli suction cup according to claim 1, characterized in that: Also included is an emergency system, the emergency system comprising: An emergency air cavity is provided inside the suction cup and is isolated from the annular air cavity; a plurality of emergency spray holes uniformly distributed on the top of the suction cup along the second circumference, the emergency spray holes being in communication with the emergency air cavity, and the distance between the emergency spray holes and the center of the suction cup being smaller than the distance between the main spray holes and the center of the suction cup; An emergency air supply pipe is provided inside the support column and is isolated from the main air supply pipe, and the emergency air supply pipe is connected to the emergency air cavity; an emergency air inlet, provided on a side wall of the support column and isolated from the main air inlet, the emergency air inlet being connected to the emergency air supply pipe; The emergency valve is arranged on the emergency air supply pipe and is electrically connected to the output end of the controller.

3. The control system of the Bernoulli suction cup according to claim 2, characterized in that: The distance between the outer edge of the emergency air cavity and the central axis of the suction cup is smaller than the distance between the outer edge of the annular portion of the main air cavity and the central axis of the suction cup.

4. The control system of the Bernoulli suction cup according to claim 2, characterized in that: A protection groove is provided on the upper surface of the suction cup, the displacement sensor is arranged at the bottom of the protection groove, and the protection groove is located in the area surrounded by the second circumference.

5. The control system of the Bernoulli suction cup according to claim 1, characterized in that: A bearing is installed between the chuck and the support column.

6. The control system of the Bernoulli suction cup according to claim 1, characterized in that: The probe of the pressure sensor is wrapped with a sealing sleeve.

7. The control system of the Bernoulli suction cup according to claim 1, characterized in that: There are multiple pressure sensors, a probe of each pressure sensor extends into one of the main injection holes, and the distance between any two adjacent pressure sensors is equal.

8. The control system of the Bernoulli suction cup according to claim 1, characterized in that: The response time of the proportional valve is less than 20ms.

9. A control method for a Bernoulli suction cup, characterized in that: At least the following steps are included: Providing a control system for a Bernoulli suction cup according to any one of claims 1 to 8; Adsorbing a wafer onto the suction cup, wherein the wafer is located within the positioning area surrounded by the clamping pins; measuring the distance between the wafer and the suction cup; The distance value is compared with a preset distance value, and the valve opening of the proportional valve is adjusted.

10. The control method of the Bernoulli suction cup according to claim 9, characterized in that: The following steps are also included: measuring the gas pressure value in the main injection hole; Compare the gas pressure value with the preset gas pressure value and adjust the switch state of the emergency valve.

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