A grinding table, wafer grinding apparatus and control method

Abstract

The application discloses a grinding workbench, a wafer grinding device and a control method. The indexing turntable of the grinding workbench is rotatably arranged on the base. The air floating pads are arranged between the base and the indexing turntable. The air floating pads are arranged at intervals along the circumference of the indexing turntable. The first air port of each air floating pad is in communication with the second air port. The second air port is arranged on the surface of the air floating pad facing the indexing turntable. The outlets of the multiple control air paths are respectively in communication with the first air ports of the multiple air floating pads. The second air ports can be supplied with air or air suction. The air blowing pressure or air suction pressure of the second air port of each air floating pad can be adjusted respectively. The air source and the vacuum source are connected with the inlets of the multiple control air paths. The air source can supply air to each control air path. The vacuum source can suction air from each control air path. According to the scheme, the multiple control air paths can control the multiple air floating pads independently. The air floating pads are prevented from interfering with each other, so that the control of the air floating pads is more stable.

Description

Technical Field

[0001] This application relates to the field of wafer processing technology, and in particular to a grinding table, wafer grinding equipment and its control method. Background Technology

[0002] Semiconductor technology, as the cornerstone of modern society, has driven progress and innovation in countless industries along with the rapid development of the semiconductor industry. Wafers are crucial components in the semiconductor industry. During wafer processing, excess material on the back side of the wafer needs to be removed to reduce silicon wafer package size, lower thermal resistance, and improve device heat dissipation. With the rapid development of IC manufacturing technology, the trend towards larger diameter and ultra-thin wafers has placed higher demands on the processing efficiency and quality of silicon wafer grinding.

[0003] In related technologies, wafer thinning involves placing the wafer on a turntable and using a thinning machine to grind and thin it to meet specific thickness requirements. Throughout the thinning process, the turntable rotates, and the axial support after rotation is typically provided by an air-bearing structure.

[0004] However, the air flotation structure is composed of multiple air flotation pads, which are connected by air pipes. The connection method of multiple air flotation pads sharing a single air path is unstable, and the multiple air flotation pads are prone to mutual interference, which cannot meet the control requirements for adjusting the air flotation pads. Summary of the Invention

[0005] This application discloses a grinding worktable, a wafer grinding equipment, and a control method, which can realize the individual control of multiple air floats by multiple control air paths, avoiding mutual interference between multiple air floats.

[0006] To achieve the above objectives, in a first aspect, embodiments of this application disclose a grinding table, which is used in wafer grinding equipment, and the grinding table includes:

[0007] Base;

[0008] Indexing turntable, which is rotatably mounted on the base, is provided with multiple carrier platforms for carrying wafers. When the indexing turntable rotates, it can drive the wafers on the carrier platforms to switch between the loading station and the grinding station.

[0009] Multiple air floats are disposed between the base and the indexing turntable, and the multiple air floats are spaced apart along the circumference of the indexing turntable. Each air float is provided with a first air port and a second air port. The first air port is connected to the second air port, and the second air port is disposed on the surface of the air float facing the indexing turntable.

[0010] Multiple control air paths are provided, and the outlets of the multiple control air paths are respectively connected to the first air ports of the multiple air floats, which can supply air or draw air to the second air ports. The multiple control air paths can respectively adjust the blowing pressure or suction pressure of the second air port of each air float.

[0011] An air source is connected to the inlet of the plurality of control air paths, and the air source is capable of supplying air to the control air paths;

[0012] A vacuum source is connected to the inlet of the plurality of control gas paths, and the vacuum source is capable of evacuating the control gas paths.

[0013] As an optional implementation, the control gas path includes a gas pipeline, a control valve assembly, and a control circuit. The first end of the gas pipeline is connected to the first gas port, and the second end of the gas pipeline is connected to the gas source or the vacuum source. The control valve assembly is disposed in the gas pipeline and is electrically connected to the control circuit. The control circuit can control the opening degree of the control valve assembly to adjust the blowing pressure or suction pressure of the second gas port.

[0014] As an optional implementation, the grinding table further includes multiple displacement sensors, each corresponding to one of the multiple air floats, and each electrically connected to the control circuit of the multiple control air paths. The displacement sensors are disposed between the air floats and the indexing turntable, and are configured to sense the displacement of the indexing turntable relative to the air floats along the rotation axis of the indexing turntable. The control circuit can control the opening degree of the control valve assembly based on the displacement sensed by the displacement sensors.

[0015] As an optional implementation, the grinding table further includes multiple air pressure sensors, each corresponding to a multiple air float, and each air pressure sensor is electrically connected to a control circuit of a multiple control air path. The air pressure sensors are disposed in the gas pipeline and are configured to sense the blowing pressure or suction pressure at the second air inlet. The control circuit can control the opening degree of the control valve assembly based on the pressure value sensed by the air pressure sensor.

[0016] As an optional implementation, the control valve assembly includes a solenoid valve and a pressure regulating valve. Both the solenoid valve and the pressure regulating valve are disposed in the gas pipeline. The solenoid valve is located between the first end of the gas pipeline and the pressure regulating valve. Both the solenoid valve and the pressure regulating valve are electrically connected to the control circuit. The solenoid valve is used to control the opening or closing of the gas pipeline. The control circuit can control the opening degree of the pressure regulating valve to adjust the blowing pressure or suction pressure of the second gas port.

[0017] As an optional implementation, the air float has a first end and a second end opposite to each other along the circumference of the indexing turntable. The end face of the first end of the air float and the end face of the second end of the air float are provided with mounting holes, and the air float is connected to the base through the mounting holes.

[0018] As an optional implementation, the gas pipeline includes a first gas pipeline and a second gas pipeline. The first gas pipeline passes through the end face of the first end of the air float, and the second gas pipeline passes through the end face of the second end of the air float. Both the first gas pipeline and the second gas pipeline are connected to the first gas port. The first gas pipeline and the second gas pipeline form an angle, and both the port of the first gas pipeline at the end face of the first end of the air float and the port of the second gas pipeline at the end face of the second end of the air float are provided with sealing elements.

[0019] Secondly, embodiments of this application provide a wafer grinding apparatus, the wafer grinding apparatus comprising:

[0020] frame;

[0021] Multiple grinding components are mounted on the frame. Each grinding component includes a grinding shaft and a grinding head. The grinding shaft is rotatably mounted on the frame, and the grinding head is connected to the grinding shaft. Rotation of the grinding shaft drives the grinding head to rotate.

[0022] As described in the first aspect above, the grinding table is disposed below the plurality of grinding components, and the grinding table is used to support the wafer.

[0023] As an optional implementation, the multiple air cushions of the grinding table correspond axially to the grinding shafts of the multiple grinding components.

[0024] Thirdly, embodiments of this application provide a method for controlling a grinding table, the method comprising:

[0025] The control circuit receives monitoring signals corresponding to multiple different circumferential positions of the indexing turntable and the air float. The monitoring signals include the relative displacement between the indexing turntable and the air float, and / or the air pressure at the air outlet of the air float.

[0026] The control circuit adjusts the pressure at the air inlet of the air float towards the indexing turntable according to the monitoring signal, so that the surface of the indexing turntable remains horizontal.

[0027] As an optional implementation, the control circuit adjusts the air pressure at the air inlet of the air-floating pad towards the indexing turntable according to the monitoring signal, including:

[0028] The control circuit outputs a control signal, which connects the control air path of the air float to the air source.

[0029] The control circuit outputs a pressure regulating signal to gradually increase the air pressure at the air inlet of the air flotation pad facing the indexing turntable, causing the indexing turntable to rise to a predetermined height; and during the rising of the indexing turntable, the pressure regulating signal output by the control circuit ensures that the differences between the multiple monitoring signals are within a preset range; or...

[0030] The control circuit outputs a pressure regulating signal to gradually reduce the air pressure at the air inlet of the air float facing the indexing turntable, causing the indexing turntable to descend until it contacts the surface of the air float; and during the descent of the indexing turntable, the pressure regulating signal output by the control circuit ensures that the differences between the multiple monitoring signals are within a preset range.

[0031] As an optional implementation, the control circuit, based on the monitoring signal, further adjusts the air pressure at the air inlet of the air-floating pad facing the indexing turntable, including:

[0032] The control circuit outputs a control signal, which connects the control air path of the air-floating pad to a vacuum source.

[0033] The control circuit outputs a pressure regulating signal to reduce the air pressure at the air inlet of the air float facing the indexing turntable, so that the indexing turntable is vacuum-adsorbed by the air float; and when the grinding worktable is in grinding operation, the pressure regulating signal output by the control circuit makes the difference between the multiple monitoring signals within a preset range.

[0034] Compared with the prior art, the beneficial effects of this application are:

[0035] This application provides a grinding table, wafer grinding equipment, and control method. The grinding table includes a base, an indexing turntable, multiple air floats, multiple control air paths, an air source, and a vacuum source. The indexing turntable is rotatably mounted on the base and is used to support the wafer. When the indexing turntable rotates, it can drive the wafer to switch between a loading station and a grinding station. Multiple air floats are disposed between the base and the indexing turntable, and the multiple air floats are spaced apart along the circumference of the indexing turntable. Each air float has a first air port. The first and second air ports are connected, with the second air port located on the surface of the air float facing the indexing turntable. Multiple control air paths connect to the corresponding first air ports of the multiple air floats, enabling air supply or extraction to the second air ports. These control air paths can also individually adjust the blowing or suction pressure of the second air port for each air float. An air source connects to the inlets of the multiple control air paths, supplying air to each path. A vacuum source connects to the inlets of the multiple control air paths, extracting air from each path. This allows for individual control of multiple air floats through multiple control air paths, preventing a problem in one air float from causing the others to malfunction during blowing or suction. It also avoids interference between the multiple air floats, resulting in more stable control of the air floats. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of the grinding table disclosed in the embodiments of this application;

[0038] Figure 2 This is a partial structural schematic diagram of the grinding table disclosed in an embodiment of this application;

[0039] Figure 3 This is a schematic diagram of the structure of the air-bearing pad disclosed in the embodiments of this application;

[0040] Figure 4 This is a simplified control logic diagram of the control gas path disclosed in the embodiments of this application;

[0041] Figure 5 This is a radial cross-sectional view of the air-bearing pad disclosed in an embodiment of this application;

[0042] Figure 6 This is a flowchart of a control method disclosed in an embodiment of this application;

[0043] Figure 7 A flowchart illustrating another control method disclosed in an embodiment of this application;

[0044] Figure 8 This is a flowchart of another control method disclosed in an embodiment of this application.

[0045] Explanation of reference numerals in the attached figures:

[0046] 100 - Grinding table;

[0047] 1-Base;

[0048] 2-Indexing rotary table;

[0049] 3-Air float; 3a-First air inlet; 3b-Second air inlet; 3c-Mounting hole; 31-First end; 32-Second end;

[0050] 4-Gas pipeline; 41-First gas pipeline; 42-Second gas pipeline;

[0051] 5-Seals. Detailed Implementation

[0052] 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.

[0053] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0054] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0055] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0056] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0057] Semiconductor technology, as the cornerstone and core driving force of modern technological society, has profoundly influenced the progress and innovation of countless industries, from consumer electronics to industrial control and high-performance computing. With the rapid advancement of the semiconductor industry, not only is the pace of technological iteration accelerating, but the performance requirements for components are also becoming increasingly stringent. Among these, the wafer, as a crucial link in the semiconductor industry chain, directly affects the performance and reliability of the final chip through its processing precision and quality. In the wafer manufacturing process, the thinning process plays a vital role. Through precise mechanical and chemical methods, the wafer thickness is reduced to the micrometer level, aiming to reduce chip size and increase integration density, thereby meeting the demands of high-performance, low-power modern electronic products. During wafer thinning, the wafer is placed on a grinding table, where it is ground and thinned by thinning components in a thinning machine to meet the required thickness. Throughout the thinning process, the vertical support of the indexing turntable of the grinding table typically uses air-bearing pads for support.

[0058] In related technologies, multiple air floats on a grinding table are connected by air pipes, and multiple air floats share a single air path. This makes it impossible to control each air float individually, and the multiple air floats are prone to mutual interference, failing to meet the control requirements for adjusting the air floats.

[0059] Based on this, this application provides a grinding worktable, a wafer grinding equipment and its control method, which can realize the individual control of multiple air floats by multiple control air paths, and avoid mutual interference between multiple air floats.

[0060] The present technical solution will be further described below with reference to the embodiments and accompanying drawings.

[0061] Please see Figures 1 to 3The first aspect of this application discloses a grinding worktable 100 for use in wafer grinding equipment. The grinding worktable 100 includes a base 1, an indexing turntable 2, multiple air floats 3, multiple control air paths, an air source, and a vacuum source (not shown in the figure). Specifically, the indexing turntable 2 is rotatably mounted on the base 1. Multiple support platforms (not shown in the figure) for carrying wafers are provided on the indexing turntable 2. When the indexing turntable 2 rotates, it can drive the wafers on the support platforms to switch between the loading station and the grinding station. Multiple air floats 3 are disposed between the base 1 and the indexing turntable 2, and the multiple air floats 3 are spaced apart circumferentially along the indexing turntable 2. Each air float 3 has a first air port 3a and a second air port 3b. The second air port 3b is located on the surface of the air-float 3 facing the indexing turntable 2. Multiple control air paths have their outlets connected to the first air ports of the air-float 3, enabling the supply or extraction of air to the second air ports 3b of the air-float 3. The control air paths can adjust the blowing or suction pressure of each second air port 3b of the air-float 3. An air source is connected to the inlet of the control air path, supplying air to it. A vacuum source is also connected to the inlet of the control air path, extracting air from each control air path. When the air source is running, it provides high-pressure gas to the control air path; when the vacuum source is running, it extracts air from the control air path, creating a vacuum state so that the indexing turntable 2 can be vacuum-adsorbed onto the air-float 3.

[0062] It should be noted that the gas source can be an air pump or an air compressor, and the vacuum source can be a vacuum generator or a vacuum pump. This embodiment does not specifically limit these.

[0063] In related technologies, since multiple air cushions 3 share a single air path, it means that the multiple air cushions 3 cannot be individually adjusted. Only the opening or closing of the second air port 3b of each air cushion 3 can be controlled, and individual control or adjustment of each air cushion 3 is not possible. However, in this embodiment, multiple control air paths allow for the separate adjustment of the blowing or suction pressure of the second air port 3b of each air cushion 3, achieving individual control of each air cushion 3, avoiding mutual interference between multiple air cushions 3, and meeting the requirement for individual adjustment of each air cushion 3.

[0064] For example, when the indexing turntable 2 needs to rotate, the second air ports 3b of the multiple air floats 3 blow air into the indexing turntable 2, causing the indexing turntable 2 to rise. The blowing pressure of the second air ports 3b of the multiple air floats 3 is adjusted by multiple control air paths, so that the blowing pressure of the second air ports 3b of each air float 3 is equal, which can ensure that the indexing turntable 2 is in a horizontal state and prevent the indexing turntable 2 from tilting during rotation.

[0065] Optionally, the rotation of the indexing turntable 2 can be driven by a drive unit. That is, the base 1 is equipped with a drive unit, and the indexing turntable 2 is connected to the drive unit through a rotating shaft. The drive unit drives the rotating shaft to rotate the indexing turntable 2.

[0066] It should be noted that the driving component can be a motor or other components capable of driving the indexing turntable 2 to rotate; this embodiment does not specifically limit this.

[0067] For example, when the wafer is placed from the loading station onto the carrier platform on the indexing turntable 2, the second air ports 3b of the multiple air pads 3 blow air to lift the indexing turntable 2, and the motor drives the rotating shaft to rotate, so as to switch the wafer on the carrier platform from the loading station to the grinding station.

[0068] For example, the indexing turntable 2 has four carrier platform placement positions, and correspondingly, there are four multiple air floats 3, each corresponding to one of the four carrier platform placement positions. At the same time, there are also four multiple control air paths, each corresponding to one of the four air floats 3, so that the four air floats 3 can be individually controlled through the four control air paths.

[0069] Furthermore, such as Figure 4 As shown, the control air path includes a gas pipeline, a control valve assembly, and a control circuit. The first end of the gas pipeline 4 is connected to the first air port 3a of the air float 3, and the second end of the gas pipeline 4 is connected to a gas source and a vacuum source. The control valve assembly is installed in the gas pipeline 4 and is electrically connected to the control circuit. The control circuit can control the opening degree of the control valve assembly to adjust the blowing pressure or suction pressure of the second air port 3b of the air float 3.

[0070] In this way, the control circuit can flexibly adjust the opening degree of the control valve assembly according to different working conditions and process requirements, thereby controlling the blowing pressure or suction pressure of the second air port 3b of the air float 3. This can meet the diverse pressure requirements of different wafer types and different processing stages. For example, at different stages of wafer thinning, the pressure can be optimized in real time to ensure consistent and high-quality thinning results. Furthermore, the control circuit, in conjunction with the control valve assembly, ensures that the pressure fluctuation of the air float 3 is small during the air supply or suction process, providing uniform and stable support force for the indexing turntable 2, avoiding shaking or vibration of the indexing turntable 2 due to unstable pressure, and improving the accuracy and stability of wafer processing.

[0071] Furthermore, such as Figure 4As shown, the control valve assembly includes a solenoid valve and a pressure regulating valve. Both the solenoid valve and the pressure regulating valve are located in the gas pipeline. The solenoid valve is situated between the first end of the gas pipeline 4 and the pressure regulating valve. Both the solenoid valve and the pressure regulating valve are electrically connected to the control circuit. The solenoid valve controls the opening or closing of the gas pipeline 4, and the control circuit controls the opening degree of the pressure regulating valve to adjust the blowing or suction pressure of the second air port 3b of the air float 3. Specifically, during the process of the gas source outputting high-pressure gas to the control gas circuit or the vacuum source evacuating gas from the control gas circuit to output a vacuum to the control gas circuit, the control circuit controls the solenoid valve to be in the open state; at other times, the control circuit controls the solenoid valve to be in the closed state.

[0072] In this way, under the control of the control circuit, the solenoid valve and pressure regulating valve can finely adjust their opening degree, thereby accurately controlling the gas pressure in the gas pipeline 4. This enables precise control of the blowing or suction pressure of the second air port 3b of the air float 3, facilitating flexible adjustment of the pressure of the air float 3 according to different processing requirements and working conditions, and improving the control accuracy of the grinding table 100. Furthermore, the pressure regulating valve can stabilize the pressure in the gas pipeline 4, reducing pressure changes caused by fluctuations in the gas source pressure or other interference factors, ensuring that the air float 3 continuously provides stable support, allowing the indexing rotary table 2 to maintain a stable suspended state when rotation is required, and improving the operational stability of the grinding table 100.

[0073] It is understandable that the control circuit controls the opening degree of the pressure regulating valve, which means that the pressure regulating valve receives the signal transmitted by the control circuit to drive the valve to change the cross-sectional area between the valve core and the valve seat (that is, to change the opening degree of the pressure regulating valve), thereby controlling the pressure, flow rate and other parameters of the gas passing through the pressure regulating valve.

[0074] In some embodiments, combined with Figure 1 and Figure 4 The grinding table 100 also includes multiple displacement sensors (not shown in the figure). Each displacement sensor corresponds to a multiple air floats 3 and is electrically connected to the control circuits of multiple control air paths. The displacement sensors are positioned between the air floats 3 and the indexing turntable 2. The displacement sensors are configured to sense the displacement of the indexing turntable 2 relative to the air floats 3 along the rotation axis of the indexing turntable 2. The control circuit can control the opening degree of the control valve assembly based on the displacement sensed by the displacement sensors. Specifically, the control circuit's ability to control the opening degree of the control valve assembly based on the displacement sensed by the displacement sensors means that the control circuit controls the opening degree of the pressure regulating valve of the control valve assembly based on the displacement sensed by the displacement sensors to adjust the gas pressure at the second air port 3b of the air floats 3.

[0075] It is understandable that multiple displacement sensors correspond to multiple air cushions 3 respectively, meaning that each air cushion 3 has at least one displacement sensor. That is to say, an air cushion 3 can be equipped with one displacement sensor or two displacement sensors, meaning that each air cushion 3 is equipped with a displacement sensor.

[0076] During the wafer thinning process, the indexing turntable 2 is attached to the air float 3. The grinding head applies pressure to the wafer, which is transmitted to the indexing turntable 2, causing varying degrees of deformation on its entire upper surface along its rotation axis. Continuing grinding would result in a wafer surface that does not meet the precision requirements. In this embodiment, a displacement sensor monitors the displacement of the indexing turntable 2 relative to the air float 3 along the rotation axis in real time and feeds the data back to the control circuit. The control circuit controls the opening degree of the control valve assembly based on the displacement, thereby adjusting the suction pressure of the air float 3 and adjusting the position of the indexing turntable 2 along the rotation axis to compensate for positional deviations on the wafer surface. This ensures that the indexing turntable 2 accurately stops at the target position, meeting the high-precision positioning requirements in wafer processing and improving the precision of the wafer after grinding.

[0077] For example, when the indexing turntable 2 falls onto the air float 3, the second air port 3b of the air float 3 draws in air, holding the indexing turntable 2 onto the air float 3. When the wafer is being ground, the grinding head applies pressure to the indexing turntable 2. After the indexing turntable 2 is subjected to pressure, it will cause the position of the indexing turntable 2 corresponding to different air float 3 to be displaced in the vertical direction. The displacement sensor can monitor the amount of displacement of the indexing turntable 2 corresponding to each air float 3 position. After the feedback is sent to the control circuit, the control circuit controls the control valve assembly to adjust the air intake pressure of the second air port 3b of the air float 3, so that the amount of displacement of the indexing turntable 2 corresponding to each air float 3 position monitored by the displacement sensor is equal, ensuring that the surface of the wafer being thinned is in the correct position.

[0078] Optionally, the displacement sensor in this embodiment is a thin-film sensor, which is disposed between the indexing turntable 2 and the air cushion 3. The thin-film sensor is thin, small in area, does not occupy too much space, is lightweight, and has minimal impact on the original balance and structure of the grinding table 100 after installation. Furthermore, the thin-film sensor is flexible, can be bent and folded, can conform to complex curved surfaces or be installed in confined spaces, and is adaptable to objects of different shapes. In addition, the thin-film sensor responds rapidly to displacement changes, can detect minute displacements, and outputs significant change signals, making it suitable for high-precision wafer grinding. Of course, the displacement sensor can also be other types of sensors, as long as they can monitor the displacement of the indexing turntable 2 relative to the air cushion 3 along the rotation axis of the indexing turntable 2. This embodiment does not specifically limit this.

[0079] Optionally, in this embodiment, a pressure sensor can be used instead of a displacement sensor. When the indexing turntable 2 is subjected to pressure, the pressure on the indexing turntable 2 will be transmitted to the corresponding pressure sensor. The pressure sensor senses the displacement of the indexing turntable 2 relative to the air float 3 along the rotation axis of the indexing turntable 2 through pressure sensing, and converts this into an electrical signal to be transmitted to the control circuit to realize the adjustment of the control valve assembly.

[0080] In some embodiments, combined with Figure 1 and Figure 4 The grinding table 100 also includes multiple air pressure sensors (not shown in the figure). Each air pressure sensor corresponds to a multiple air floats 3, and each air pressure sensor is electrically connected to a control circuit of a multiple control air path. The air pressure sensors are installed in the gas pipeline and are configured to sense the blowing pressure or suction pressure at the second air port 3b of the air float 3. The control circuit can control the opening degree of the control valve assembly based on the pressure value sensed by the air pressure sensor. Specifically, the control circuit's ability to control the opening degree of the control valve assembly based on the pressure value sensed by the air pressure sensor means that the control circuit controls the opening degree of the pressure regulating valve of the control valve assembly based on the pressure value sensed by the air pressure sensor, thereby adjusting the gas pressure at the second air port 3b of the air float 3.

[0081] It should be noted that the correspondence between multiple air pressure sensors and multiple air floats 3 means that each air float 3 has at least one air pressure sensor. In other words, an air float 3 can be equipped with one air pressure sensor or two air pressure sensors, meaning that each air float 3 is equipped with a corresponding air pressure sensor.

[0082] When the indexing turntable 2 needs to rotate, the second air ports 3b of the multiple air floats 3 blow air into the indexing turntable 2 to lift it. During the lifting process, if the blowing pressure at the second air ports 3b of the multiple air floats 3 is different, it will cause the indexing turntable 2 to tilt. Therefore, in this embodiment, the blowing pressure value at the second air ports 3b of the air floats 3 is monitored in real time by a pressure sensor, and the data is fed back to the control circuit. The control circuit adjusts the opening degree of the control valve assembly accordingly to ensure that the pressure values ​​at the second air ports 3b of the multiple air floats 3 monitored by the pressure sensor are equal, thus ensuring that the surface of the indexing turntable 2 is in a horizontal state after being lifted.

[0083] For example, during the lifting process of the indexing turntable 2, the air pressure sensor monitors the blowing pressure value at the second air port 3b of the air float 3 in real time. When the blowing pressure value at the second air port 3b of a certain air float 3 monitored by the air pressure sensor is lower than the blowing pressure value at the second air port 3b of other air float 3, a signal is transmitted to the control circuit. The control circuit controls the opening degree of the control valve assembly to increase the blowing pressure at the second air port 3b of the air float 3 at this point, so that the blowing pressure at the second air port 3b of each air float 3 is equal, ensuring that the indexing turntable 2 is in a horizontal state during the lifting process.

[0084] In some embodiments, the grinding table 100 may further include multiple photoelectric displacement sensors, each corresponding to a multiple air cushions 3, and the photoelectric displacement sensors are disposed on the side of the air cushions 3. The photoelectric displacement sensors are electrically connected to the control circuit. Using photoelectric displacement sensors, the displacement information of the indexing turntable 2 relative to the air cushions 3 on the axis can be acquired, and signals are transmitted to the control circuit based on the displacement information. This allows the control circuit to control the opening degree of the control valve assembly according to the acquired displacement information, thereby adjusting the gas pressure at the second air port 3b of the air cushions 3. Through the combined action of the photoelectric displacement sensors and the air pressure sensors, the distance between the indexing turntable 2 and the air cushions 3 and the gas pressure value at the second air port 3b of each air cushion 3 can be monitored in real time, ensuring that the indexing turntable 2 remains horizontal during the lifting process.

[0085] In some embodiments, combined with Figure 1 and Figure 5 The air float 3 has a first end 31 and a second end 32 opposite to each other along the circumference of the indexing turntable 2. The end face of the first end 31 and the end face of the second end 32 of the air float 3 are provided with mounting holes 3c. The air float 3 is connected to the base 1 through the mounting holes 3c.

[0086] In other words, the air cushion 3 is fixed to the base 1 from the circumference of the air cushion 3, rather than from top to bottom along the vertical direction using fasteners. If the air cushion 3 is fixed to the base 1 vertically using fasteners, it may cause the air cushion 3 to be compressed in the vertical direction. After being compressed, stress concentration will occur in the mounting hole 3c, which may cause cracks to appear near the mounting hole 3c, making the air cushion 3 unusable.

[0087] Therefore, in this embodiment, the air float 3 is connected to the base 1 via the mounting holes 3c on the end faces of both ends, which avoids the air float 3 being subjected to vertical force during connection and thus prevents cracking and other problems, ensuring the service life of the air float 3. Furthermore, the mounting holes 3c on the end faces of both ends of the air float 3 prevent the fasteners from affecting the surface of the air float 3 after installation, ensuring the precision of the upper surface of the air float 3.

[0088] In some embodiments, combined with Figure 3 and Figure 5 The gas pipe 4 includes a first gas pipe 41 and a second gas pipe 42. The first gas pipe 41 passes through the end face of the first end 31 of the air float 3, and the second gas pipe 42 passes through the end face of the second end 32 of the air float 3. Both the first gas pipe 41 and the second gas pipe 42 are connected to the first air port 3a of the air float 3. The first gas pipe 41 and the second gas pipe 42 form an angle. Both the port of the first gas pipe 41 at the end face of the first end of the air float 3 and the port of the second gas pipe 42 at the end face of the second end of the air float 3 are provided with a sealing element 5.

[0089] This means that the first gas pipe 41 and the second gas pipe 42 are processed from the end face of the first end 31 and the end face of the second end 32 of the air float 3 inwards during manufacturing. In other words, the air float 3 in this embodiment is integrally formed. In related technologies, the air float 3 is processed in two parts, and then the two parts are connected to form the gas pipe 4, requiring a seal at the connection point. Therefore, in this embodiment, the forming method of the first gas pipe 41 and the second gas pipe 42 is simpler, which helps reduce the manufacturing cost of the air float 3. Furthermore, after forming, only the ports of the first gas pipe 41 and the second gas pipe 42 near the end face of the air float 3 need to be sealed with a sealing element 5 to ensure the airtightness of the first gas pipe 41 and the second gas pipe 42, eliminating the need for large-area sealing and saving costs.

[0090] It should be noted that the sealing element 5 can be a plug, a sealing head, or other components that can seal the port; this embodiment does not specifically limit this.

[0091] Secondly, this application discloses a wafer grinding apparatus for thinning wafers. The wafer grinding apparatus includes a frame, multiple grinding components, and a grinding table 100 as described in the first aspect above. Specifically, the multiple grinding components are disposed on the frame, and each grinding component includes a grinding shaft and a grinding head. The grinding shaft is rotatably disposed on the frame, and the grinding head is connected to the grinding shaft. The rotation of the grinding shaft drives the grinding head to rotate. The grinding table 100 is disposed below the multiple grinding components and is used to support the wafer.

[0092] The wafer grinding equipment employing the grinding table 100 allows for individual adjustment of the blowing or suction pressure of the second air port 3b of each air float 3 on the grinding table 100 via multiple control air paths. This achieves individual control of each air float 3, preventing mutual interference between the multiple air floats 3 and fulfilling the requirement for individual adjustment of each air float 3. When the grinding head grinds the wafer, the control air paths of the grinding table 100 can adjust the suction pressure of the second air port 3b of the air float 3 to ensure the wafer is in the correct position on the grinding table 100, thus improving the surface accuracy of the wafer after grinding.

[0093] Furthermore, the multiple air cushions 3 of the grinding table 100 correspond axially to the grinding shafts of the multiple grinding components.

[0094] In this way, when the indexing turntable 2 of the grinding table 100 rotates with the wafer to the grinding station, the wafer, the air float 3 and the grinding shaft are all on the axial direction of the grinding shaft. When the grinding head presses down on the wafer, the air float 3 can provide more stable axial support, enhancing the load-bearing capacity and stability of the entire grinding table 100.

[0095] Thirdly, see Figure 6 This application also provides a method for controlling a grinding table, the method comprising:

[0096] The control circuit receives monitoring signals corresponding to multiple different circumferential positions of the indexing turntable and the air float 3. The monitoring signals include the relative displacement between the indexing turntable 2 and the air float 3, and / or the air pressure at the air inlet of the air float 3 facing the indexing turntable 2.

[0097] The control circuit adjusts the pressure at the air inlet of the air float 3 according to the monitoring signal, so that the surface of the indexing turntable 2 remains horizontal.

[0098] Among them, the air inlet of the air cushion 3 facing the indexing turntable 2 is the second air inlet 3b of the air cushion 3. The relative displacement between the indexing turntable 2 and the air cushion 3 is obtained by a displacement sensor, and the air pressure at the air outlet of the air cushion 3 is obtained by an air pressure sensor.

[0099] In this way, by monitoring the relative displacement between the indexing turntable 2 and the air cushion 3 and / or the air pressure at the air inlet of the air cushion 3, the control circuit adjusts the air pressure in real time to ensure that the surface of the indexing turntable 2 remains horizontal. This avoids processing errors caused by the tilt of the indexing turntable 2, improves processing accuracy, and ensures the consistency and stability of the processed quality.

[0100] Furthermore, such as Figure 7As shown, the control circuit adjusts the air pressure at the air inlet of the air float 3 facing the indexing turntable 2 according to the monitoring signal, including:

[0101] The control circuit outputs a control signal, which connects the control air path of the air float 3 to the air source.

[0102] The control circuit outputs a pressure regulating signal, gradually increasing the air pressure at the air inlet of the air bearing pad 3 facing the indexing turntable 2, causing the indexing turntable 2 to rise to a predetermined height; and during the rising of the indexing turntable 2, the pressure regulating signal output by the control circuit ensures that the differences between multiple monitoring signals are within a preset range; or,

[0103] The control circuit outputs a pressure regulating signal to gradually reduce the air pressure at the air inlet of the air float 3 toward the indexing turntable 2, causing the indexing turntable 2 to float and descend until it contacts the surface of the air float 3; and during the descent of the indexing turntable 2, the pressure regulating signal output by the control circuit ensures that the differences between multiple monitoring signals are within a preset range.

[0104] The voltage regulation signal output by the control circuit ensures that the differences between multiple monitoring signals are within a preset range. This means that the differences between the received monitoring signals after adjustment by the voltage regulation signal of the control circuit are within an acceptable range and will not affect the operation process.

[0105] Specifically, when the indexing turntable 2 needs to rotate, the control circuit outputs a control signal, and the control air source is connected to the gas pipeline of the control air circuit. The air source inputs high-pressure gas into the gas pipeline. Then, the control circuit controls the solenoid valve to open and controls the pressure regulating valve to open, and outputs a pressure regulating signal to the pressure regulating valve. This gradually increases the air pressure at the air inlet of the air float 3 facing the indexing turntable 2, so that multiple air floats 3 blow high-pressure gas towards the air inlet of the indexing turntable 2 to make the indexing turntable 2 float up to the predetermined height. During the air-float ascent of the indexing turntable 2, the air pressure at the air inlet of each air-float 3 facing the indexing turntable 2 is monitored in real time by air pressure sensors. If the air pressure value at the air inlet of one air-float 3 facing the indexing turntable 2 is different from the air pressure values ​​at the air inlets of the other air-float 3 facing the indexing turntable 2, a monitoring signal is transmitted to the control circuit. The control circuit outputs a pressure regulating signal to the pressure regulating valve according to the received monitoring signal, and controls the opening degree of the pressure regulating valve to adjust the air pressure at the air inlets of the air-float 3 facing the indexing turntable 2. This ensures that the difference in the air pressure values ​​at the air inlets of the air-float 3 monitored by each air pressure sensor is within a preset range, thus ensuring that the surface of the indexing turntable 2 remains horizontal during the air-float process.

[0106] When the indexing turntable 2 needs to descend back onto the air cushion 3, the control circuit outputs a pressure regulating signal to the pressure regulating valve. The control circuit controls the pressure regulating valve to gradually close, so that the air pressure at the air inlets of the multiple air cushions 3 facing the indexing turntable 2 gradually decreases, causing the indexing turntable 2 to descend until it contacts the surface of the air cushion 3. During the descent of the indexing turntable 2, the air pressure sensor monitors the air pressure at the air inlets of the air pads 3 facing the indexing turntable 2 in real time. If the air pressure value at the air inlet of one air pad 3 facing the indexing turntable 2 is different from the air pressure values ​​at the air inlets of the other air pads 3 facing the indexing turntable 2, a monitoring signal is transmitted to the control circuit. The control circuit outputs a pressure regulating signal to the pressure regulating valve according to the received monitoring signal, and controls the opening degree of the pressure regulating valve to adjust the air pressure at the air inlets of the air pads 3 facing the indexing turntable 2, so that the difference between the air pressures at the air inlets of the air pads 3 facing the indexing turntable 2 monitored by each air pressure sensor is within a preset range, ensuring that the surface of the indexing turntable 2 remains horizontal during the descent.

[0107] Furthermore, such as Figure 8 As shown, the control circuit adjusts the air pressure at the air inlet of the air float 3 facing the indexing turntable 2 according to the monitoring signal, and also includes:

[0108] The control circuit outputs a control signal, which connects the control air path of the air-floating pad 3 to the vacuum source.

[0109] The control circuit outputs a pressure regulating signal to reduce the air pressure at the air inlet of the air float 3 toward the indexing turntable 2, so that the indexing turntable 2 is vacuum-adsorbed by the air float 3; and when the grinding worktable is in the grinding operation, the pressure regulating signal output by the control circuit makes the difference between multiple monitoring signals within a preset range.

[0110] Specifically, when the indexing turntable 2 needs to be adsorbed onto the air float 3, the control circuit outputs a control signal to control the vacuum source to connect to the gas pipeline of the control gas path. The control circuit controls the solenoid valve to open and controls the pressure regulating valve to open. The control circuit outputs a pressure regulating signal to the pressure regulating valve to adjust the opening degree of the pressure regulating valve, thereby reducing the air pressure at the air port of the air float 3 facing the indexing turntable 2, so that the air port of the air float 3 facing the indexing turntable 2 is in a suction state, so as to vacuum adsorb the indexing turntable 2 onto the air float 3. When the grinding table is in the grinding operation, the wafer on the bearing platform of the indexing turntable 2 needs to be ground. The indexing turntable 2 will be displaced along the axial direction due to the pressure of the grinding shaft. The displacement of the indexing turntable 2 relative to the air float 3 corresponding to multiple air floats 3 is monitored in real time by displacement sensors. The displacement values ​​monitored by multiple displacement sensors are compared. If the displacement value monitored by the displacement sensor on a certain air float 3 is greater than the displacement values ​​monitored by the displacement sensors of the other air floats 3, the control circuit outputs a pressure regulating signal to the pressure regulating valve of the air float 3 to reduce its pressure. After receiving the pressure reducing signal, the pressure regulating valve reduces the pressure, and the solenoid valve outputs a lower pressure vacuum, so that the indexing turntable 2 and the air float 3 are more tightly attached. Conversely, if the displacement value monitored by the displacement sensor on a certain air cushion 3 is less than the displacement values ​​monitored by the displacement sensors on the other air cushions 3, the control circuit outputs a pressure regulating signal to the pressure regulating valve of that air cushion 3. After receiving the pressure regulating signal, the pressure regulating valve increases the pressure, and the solenoid valve outputs a higher vacuum, making the indexing turntable 2 more loosely attached to the air cushion 3 at that position, so that the displacement values ​​monitored by multiple displacement sensors are the same. This ensures that the pressure regulating signal output by the control circuit keeps the difference between multiple monitoring signals within a preset range, ensuring that the indexing turntable 2 is in a horizontal state and ensuring the accuracy of the grinding table during grinding.

[0111] Optionally, when the indexing turntable 2 needs to rotate, the control circuit outputs a control signal to control the gas source to enter the gas pipeline. The gas source inputs high-pressure gas into the gas pipeline. At this time, the control circuit controls the solenoid valve to open and controls the pressure regulating valve to open, so that multiple air floats 3 blow high-pressure gas toward the air port of the indexing turntable 2 so that the indexing turntable 2 is in an air-floating state. At this time, the gas pressure value at the air inlet of each air float 3 facing the indexing turntable 2 is monitored in real time by a pressure sensor, and / or the displacement of the indexing turntable 2 relative to the air float 3 is monitored in real time by a photoelectric displacement sensor. If the gas pressure value at the air inlet of one air float 3 facing the indexing turntable 2 is different from the gas pressure values ​​at the air inlets of the other air floats 3 facing the indexing turntable 2, or if the displacement of the indexing turntable 2 relative to the air float 3 monitored by one photoelectric displacement sensor is different from the displacement of the indexing turntable 2 relative to the air float 3 monitored by the other photoelectric displacement sensors, a monitoring signal is transmitted to the control circuit. The control circuit controls the opening degree of the pressure regulating valve according to the received monitoring signal to adjust the gas pressure at the air inlet of the air float 3 facing the indexing turntable 2, so that the gas pressure values ​​at the air inlets of the air float 3 facing the indexing turntable 2 monitored by each pressure sensor are equal, ensuring that the surface of the indexing turntable 2 remains horizontal during the air floatation process.

[0112] In some embodiments, continuous pressure regulation can be achieved through the control circuit in conjunction with the pressure sensor. When the indexing turntable 2 needs to rotate, the control circuit controls the gas source to be connected to the gas pipeline. The gas source inputs high-pressure gas into the gas pipeline. At this time, the control circuit controls the solenoid valve to open and controls the pressure regulating valve to open, inputting the initial step pressure value into the control circuit. The control circuit controls the pressure regulating valve to increase the pressure according to the step pressure value. The pressure regulating valve continuously increases the pressure, inputting high-pressure gas at the specified pressure to the solenoid valve. The solenoid valve connects the output terminal and outputs high-pressure gas with gradually increasing pressure, thereby raising the indexing turntable 2 to rise at a uniform speed. During this process, the air pressure sensors monitor the gas pressure values ​​output by each air cushion 3 at the air inlet facing the indexing turntable 2 in real time, and compare these pressure values ​​with the initial pressure values. If the gas pressure value detected by the air pressure sensor is higher than the initial pressure value, the control circuit transmits a pressure reduction signal to the pressure regulating valve, and the pressure regulating valve reduces the pressure upon receiving the pressure reduction signal. If the gas pressure value detected by the air pressure sensor is lower than the initial pressure value, the control circuit transmits a pressure increase signal to the pressure regulating valve, and the pressure regulating valve increases the pressure upon receiving the pressure increase signal, so as to ensure that the pressure values ​​output by each air cushion 3 at the air inlet facing the indexing turntable 2 are equal in real time, thereby achieving a uniform horizontal rise of the indexing turntable 2.

[0113] Optionally, during the process of the indexing turntable 2 descending back to the air cushion 3, the air pressure sensors of multiple air cushions 3 will also monitor the gas pressure value output at the air inlet of their respective air cushions 3 facing the indexing turntable 2 in real time, and compare the pressure value with the initial pressure value. If the gas pressure value detected by the air pressure sensor is higher than the initial pressure value, the control circuit transmits a pressure reduction signal to the pressure regulating valve. After receiving the pressure reduction signal, the pressure regulating valve reduces the pressure. If the gas pressure value detected by the air pressure sensor is lower than the initial pressure value, the control circuit transmits a pressure increase signal to the pressure regulating valve. After receiving the pressure increase signal, the pressure regulating valve increases the pressure. This ensures that the pressure value output at the air inlet of each air cushion 3 facing the indexing turntable 2 is equal in real time, so as to achieve the horizontal and uniform descent of the indexing turntable 2.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A grinding worktable (100), characterized in that, For use in wafer grinding equipment, the grinding table (100) includes: Base (1); Indexing turntable (2), the indexing turntable (2) is rotatably mounted on the base (1), the indexing turntable (2) is provided with a plurality of carrier platforms for carrying wafers, when the indexing turntable (2) rotates, it can drive the wafers on the carrier platforms to switch between the loading station and the grinding station; Multiple air floats (3) are disposed between the base (1) and the indexing turntable (2), and the multiple air floats (3) are spaced apart along the circumference of the indexing turntable (2). Each air float (3) is provided with a first air port (3a) and a second air port (3b). The first air port (3a) communicates with the second air port (3b), and the second air port (3b) is disposed on the surface of the air float (3) facing the indexing turntable (2). Multiple control air paths, the outlets of the multiple control air paths are respectively connected to the first air port (3a) of the multiple air floats (3), and can supply or evacuate air to the second air port (3b). The multiple control air paths can respectively adjust the blowing pressure or suction pressure of the second air port (3b) of each air float (3). An air source is connected to the inlet of the plurality of control air paths, and the air source is capable of supplying air to each of the control air paths; A vacuum source is connected to the inlet of the plurality of control gas paths, and the vacuum source is capable of evacuating air from each of the control gas paths.

2. The grinding table (100) according to claim 1, characterized in that, The control gas path includes a gas pipeline, a control valve assembly, and a control circuit. The first end of the gas pipeline is connected to the first gas port (3a), and the second end of the gas pipeline is connected to the gas source or the vacuum source. The control valve assembly is disposed in the gas pipeline and is electrically connected to the control circuit. The control circuit can control the opening degree of the control valve assembly to adjust the blowing pressure or suction pressure of the second gas port (3b).

3. The grinding table (100) according to claim 2, characterized in that, The grinding table (100) also includes multiple displacement sensors, which correspond to the multiple air floats (3) respectively, and are electrically connected to the control circuits of the multiple control air paths respectively. The displacement sensors are disposed between the air floats (3) and the indexing turntable (2). The displacement sensors are configured to sense the displacement of the indexing turntable (2) relative to the air floats (3) along the rotation axis of the indexing turntable (2). The control circuit can control the opening degree of the control valve assembly according to the displacement sensed by the displacement sensor.

4. The grinding table (100) according to claim 2, characterized in that, The grinding table (100) also includes multiple air pressure sensors, which correspond to the multiple air floats (3) respectively, and are electrically connected to the control circuits of the multiple control air paths respectively. The air pressure sensors are located in the gas pipeline and are configured to sense the blowing pressure or suction pressure at the second air port (3b). The control circuit can control the opening degree of the control valve assembly according to the pressure value sensed by the air pressure sensor.

5. The grinding table (100) according to claim 2, characterized in that, The control valve assembly includes a solenoid valve and a pressure regulating valve. Both the solenoid valve and the pressure regulating valve are disposed in the gas pipeline. The solenoid valve is located between the first end of the gas pipeline and the pressure regulating valve. Both the solenoid valve and the pressure regulating valve are electrically connected to the control circuit. The solenoid valve is used to control the opening or closing of the gas pipeline. The control circuit can control the opening degree of the pressure regulating valve to adjust the blowing pressure or suction pressure of the second gas port (3b).

6. The grinding table (100) according to claim 1, characterized in that, The air float (3) has a first end (31) and a second end (32) opposite each other along the circumference of the indexing turntable (2). The end face of the first end (31) and the end face of the second end (32) of the air float (3) are provided with mounting holes (3c). The air float (3) is connected to the base (1) through the mounting holes (3c).

7. The grinding table (100) according to claim 2, characterized in that, The gas pipe (4) includes a first gas pipe (41) and a second gas pipe (42). The first gas pipe (41) passes through the end face of the first end (31) of the air float (3), and the second gas pipe (42) passes through the end face of the second end (32) of the air float (3). Both the first gas pipe (41) and the second gas pipe (42) are connected to the first gas port (3a). The first gas pipe (41) and the second gas pipe (42) form an angle. Both the port of the first gas pipe (41) located at the end face of the first end (31) of the air float (3) and the port of the second gas pipe (42) located at the end face of the second end (32) of the air float (3) are provided with a sealing element (5).

8. A wafer grinding equipment, characterized in that, The wafer grinding equipment includes: frame; Multiple grinding components are mounted on the frame. Each grinding component includes a grinding shaft and a grinding head. The grinding shaft is rotatably mounted on the frame, and the grinding head is connected to the grinding shaft. Rotation of the grinding shaft drives the grinding head to rotate. The grinding stage (100) as described in any one of claims 1-7, wherein the grinding stage (100) is disposed below the plurality of grinding components, and the grinding stage (100) is used to carry wafers.

9. A method for controlling a grinding worktable, characterized in that, The control method includes: The control circuit receives monitoring signals corresponding to multiple different circumferential positions of the indexing turntable and the air float. The monitoring signals include the relative displacement between the indexing turntable and the air float, and / or the air pressure at the air inlet of the air float facing the indexing turntable. The control circuit adjusts the air pressure at the air inlet of the air float facing the indexing turntable according to the monitoring signal, so that the surface of the indexing turntable remains horizontal.

10. The control method for the grinding table according to claim 9, characterized in that, The control circuit adjusts the air pressure at the air inlet of the air-floating pad facing the indexing turntable according to the monitoring signal, including: The control circuit outputs a control signal, which connects the control air path of the air float to the air source. The control circuit outputs a pressure regulating signal to gradually increase the air pressure at the air inlet of the air flotation pad facing the indexing turntable, causing the indexing turntable to rise to a predetermined height; and during the rising of the indexing turntable, the pressure regulating signal output by the control circuit ensures that the differences between the multiple monitoring signals are within a preset range; or... The control circuit outputs a pressure regulating signal to gradually reduce the air pressure at the air inlet of the air float facing the indexing turntable, causing the indexing turntable to descend until it contacts the surface of the air float; and during the descent of the indexing turntable, the pressure regulating signal output by the control circuit ensures that the differences between the multiple monitoring signals are within a preset range.

11. The control method for the grinding table according to claim 10, characterized in that, The control circuit, based on the monitoring signal, adjusts the air pressure at the air inlet of the air-floating pad facing the indexing turntable, and further includes: The control circuit outputs a control signal, which connects the control air path of the air-floating pad to a vacuum source. The control circuit outputs a pressure regulating signal to reduce the air pressure at the air inlet of the air float facing the indexing turntable, so that the indexing turntable is vacuum-adsorbed by the air float; and when the grinding worktable is in grinding operation, the pressure regulating signal output by the control circuit makes the difference between the multiple monitoring signals within a preset range.

Images