Wafer loading state detection device and polishing device

Abstract

The present invention relates to the field of integrated circuit chip manufacturing and discloses a wafer loading status detection device and polishing device. The wafer loading status detection device includes: a control system, a self-capacitive touch sensor, an elastic device, and an insulating touch plate connected in sequence; the other end of the insulating touch plate contacts the first surface of an airbag, and the second surface of the airbag is used to load the wafer; when the wafer is not loaded on the second surface of the airbag or the wafer loading state is abnormal, the first surface of the airbag bulges toward the second surface of the insulating touch plate based on air pressure, pushing the insulating touch plate. When the self-capacitive touch sensor determines that the insulating touch plate and the self-capacitive touch sensor are in contact, a loading status abnormality signal is sent to the control system. The present invention determines the loading status of the wafer by determining whether the self-capacitive touch sensor is in contact with the insulating touch plate. This detection method is less affected by the airtightness and precision of the device and has a high detection accuracy rate.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit chip manufacturing, and in particular to a wafer loading state detection device and a polishing device. Background Art

[0002] In the fields of integrated circuit manufacturing and ultra-precision machining, chemical mechanical polishing (CMP) is a key process for achieving global wafer planarization. During the CMP process, the polishing head must complete actions such as loading the wafer, pressing the wafer down for polishing, sucking the wafer from the polishing pad, rotating the wafer, and unloading the wafer. To avoid damage to the wafer, the polishing head backing film, and other polishing area components, the polishing head must detect whether the wafer loading status within the polishing head is normal before and after performing any of these actions. If the wafer loading status is determined to be abnormal, all relevant moving parts in the polishing area should be immediately stopped and an equipment alarm should be triggered until the fault is corrected. Therefore, real-time and accurate detection of the wafer loading status on the polishing head is particularly important.

[0003] The existing polishing head design uses a mechanical structure combined with the upper pressure control unit's holding pressure feedback to determine the wafer's loading status within the polishing head. When a wafer is loaded onto the polishing head, the polishing head chamber connected to the air valve is in a holding pressure state, while the polishing head chamber in contact with the wafer is in a vacuum state. At this point, the flexible airbag back membrane forms a certain degree of indentation, and under the action of air pressure, the flexible airbag back membrane adsorbs the wafer. If wafer adsorption is normal during this process, the degree of indentation of the flexible airbag back membrane is insufficient for the plunger to compress the spring to open the air valve, and the holding pressure feedback of the polishing head chamber connected to the air valve is above the judgment threshold, and the system determines that the wafer loading status is normal. If wafer adsorption is abnormal or not adsorbed during this process, the degree of indentation of the flexible airbag back membrane increases, and the plunger compresses the spring to open the air valve, relieving the pressure in the polishing head chamber connected to the air valve. The holding pressure feedback of the polishing head chamber connected to the air valve is below the judgment threshold, and the system determines that the wafer loading status is abnormal.

[0004] However, existing detection schemes require high assembly precision for mechanical structures such as universal joints, air valves, springs, and plungers. Assembling the polishing head is highly dependent on the experience and proficiency of the head assembler. Assembly errors can easily cause the air valve to frequently mis-trigger or fail to trigger, thereby rendering the polishing head wafer loading status detection function ineffective and increasing the use and testing costs of the polishing head. Existing detection schemes rely on the pressure feedback of the air chamber connected to the air valve. After wafer loading is completed, the air chamber connected to the air valve must maintain a pressure hold in any non-polishing operation to determine the wafer loading status. However, due to assembly errors and hardware airtightness constraints, this air circuit system is inevitably in a slow leak state. Therefore, the pressure hold pressure gradually approaches the judgment threshold over time. Under conditions where the interval between polishing head actions is long, the detection accuracy of the polishing head wafer loading status is poor, which can easily lead to misjudgments and trigger system alarms, affecting the stable operation time of the CMP equipment and product output efficiency. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to solve the problem that the detection of wafer loading status in the prior art depends on the airtight conditions and assembly errors of the detection device, resulting in low detection accuracy, thereby providing a wafer loading status detection device and a polishing device.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a wafer loading status detection device, comprising: a self-capacitive touch sensor, an elastic device and an insulating touch plate, wherein the self-capacitive touch sensor has a first surface connected to an input end of a control system, and a second surface connected to the first end of the elastic device; the elastic device has a second end connected to the first surface of the insulating touch plate; the insulating touch plate has a second surface in contact with the first surface of an airbag; the airbag has a second surface for loading wafers, and the wafer is loaded on the second surface of the airbag after the airbag is evacuated; when the wafer is not loaded on the second surface of the airbag or the wafer loading status is abnormal, the first surface of the airbag bulges toward the second surface of the insulating touch plate based on air pressure, and after pushing the insulating touch plate to contract the elastic device, the first surface of the insulating touch plate contacts the second surface of the self-capacitive touch sensor, and the self-capacitive touch sensor determines that the insulating touch plate is in contact with the self-capacitive touch sensor, and sends a loading status abnormality signal to the control system.

[0008] The wafer loading status detection device provided by the present invention uses a self-capacitance touch sensor to determine whether the first surface of the airbag is deformed by determining whether its second surface is in contact with the first surface of the insulating touch plate, thereby determining the loading status of the wafer on the second surface of the airbag. Compared with the method in the related art of determining the loading status of the wafer by detecting the size of the holding pressure of the air chamber, the self-capacitance touch sensor of the present invention detects the loading status of the wafer on the second surface of the airbag by determining the contact status of itself with the insulating touch plate, and does not need to detect the holding pressure of the air path in the device. Therefore, the detection process does not depend on the air tightness of the device, and the sensitivity is not affected by the experience and proficiency of the assembly workers, and does not depend on the assembly error of the device. The detection accuracy and reliability are high.

[0009] In an optional embodiment, the self-capacitance touch sensor includes: a capacitance oscillation module, a comparison module and an output module, wherein the capacitance oscillation module has an input end connected to an external power supply, an output end connected to an input end of the comparison module, and a first end thereof is the second surface of the self-capacitance touch sensor. Based on the voltage and current of the external power supply, the capacitance oscillation module collects the electrical signal in the circuit through the internal sampling capacitor and outputs the sampling capacitance oscillation frequency, and outputs the touch capacitance oscillation frequency through the internal touch capacitor. After the touch capacitor changes its own capacitance based on the contact state between the insulating touch plate and the first end of the capacitance oscillation module, the capacitance oscillation module adjusts the size of the touch capacitance oscillation frequency; the comparison module has an output end connected to the input end of the output module, and is used to calculate the sampling capacitance oscillation frequency. After calculating the frequency ratio of the capacitor oscillation frequency and the touch capacitor oscillation frequency, the frequency ratio is compared with a preset value; an output module, whose output end is connected to the input end of the control system; when the wafer is normally loaded on the second surface of the airbag, the insulating touch plate does not contact the first end of the capacitor oscillation module, and the capacitance of the touch capacitor of the capacitor oscillation module remains unchanged. When the comparison module determines that the frequency ratio is equal to the preset value, the output module outputs a normal loading status signal to the control system; when the wafer is not loaded on the second surface of the airbag or the loading status is abnormal, the insulating touch plate contacts the first end of the capacitor oscillation module, and the capacitance of the touch capacitor of the capacitor oscillation module increases. When the comparison module determines that the frequency ratio is not equal to the preset value, the output module outputs an abnormal loading status signal to the control system.

[0010] The wafer loading status detection device provided by the present invention has the following characteristics: when the second surface of the self-capacitance touch sensor contacts the first surface of the insulating touch plate, the self-capacitance touch sensor changes the capacitance of the touch capacitor according to the contact pressure, thereby changing the size of the output touch capacitor oscillation frequency; the comparison module controls the output module to output a normal or abnormal loading status signal by judging the size of the frequency ratio between the sampling capacitor oscillation frequency and the touch capacitor oscillation frequency; the output of the self-capacitance touch sensor is only related to the touch pressure, and the comparison result of the comparison module is only related to the oscillation frequency; the loading status of the wafer is judged by the electrical signal, which does not depend on the airtightness of the device; the detection result is highly reliable, and the detection method is easy to implement.

[0011] In an optional embodiment, the self-capacitance touch sensor further includes: a touch electrode, a first surface of which is connected to the second surface of the self-capacitance touch sensor, and a second surface of which is connected to the first end of the elastic device. After the capacitance oscillation module changes the capacitance of the touch capacitor based on the contact state between the insulating touch plate and the touch electrode, the magnitude of the touch capacitance oscillation frequency is adjusted to maintain the magnitude of the sampling capacitance oscillation frequency unchanged.

[0012] The wafer loading state detection device provided by the present invention can quickly transfer the charge in the insulating touch plate to the self-capacitive touch sensor through the touch electrode, thereby improving the response speed of the self-capacitive touch sensor and thus improving the detection efficiency of the detection device.

[0013] In an optional embodiment, the capacitance oscillation module includes: a sampling capacitance oscillation module and a touch capacitance oscillation module, wherein the sampling capacitance oscillation module has an input end connected to an external power supply, an output end connected to an input end of a comparison module, and outputs a sampling capacitance oscillation frequency based on the voltage and current of the external power supply; the touch capacitance oscillation module has an input end connected to an external power supply, an output end connected to an input end of a comparison module, and a first end connected to a first surface of a touch electrode, and outputs a touch capacitance oscillation frequency based on the voltage and current of the external power supply, and adjusts the magnitude of the touch capacitance oscillation frequency after changing the capacitance value based on the contact state between the insulating touch plate and the touch electrode; the comparison module calculates and obtains a frequency ratio between the sampling capacitance oscillation frequency and the touch capacitance oscillation frequency, and compares the ratio with a preset value; when the comparison module determines that the frequency ratio is equal to the preset value, the output module outputs a normal loading state signal to the control system; when the comparison module determines that the frequency ratio is not equal to the preset value, the output module outputs an abnormal loading state signal to the control system.

[0014] In an optional implementation, the sampling capacitor oscillation frequency is:

[0015]

[0016] Among them, f s is the sampling capacitor oscillation frequency; Cs is the capacitance of the sampling capacitor in the sampling capacitor oscillation module; V erf is the external power supply voltage; I ref is the external power supply current.

[0017] The touch capacitance oscillation frequency is:

[0018]

[0019] Among them, f x is the touch capacitance oscillation frequency; C x is the capacitance of the touch capacitor in the touch capacitor oscillation module.

[0020] In an optional implementation, a frequency ratio calculation formula of the sampling capacitor oscillation frequency and the touch capacitor oscillation frequency is:

[0021]

[0022] Among them, C0 is the initial capacitance of the touch capacitor; A is the difference between C0 and C s The ratio of ΔC x is the increment of the current touch capacitance compared to the initial touch capacitance.

[0023] In an optional embodiment, when the comparison module determines that the frequency ratio is equal to the ratio of the initial capacitance of the touch capacitor to the capacitance of the sampling capacitor, the output module outputs a normal loading state signal to the control system; when the comparison module determines that the frequency ratio is not equal to the ratio of the initial capacitance of the touch capacitor to the capacitance of the sampling capacitor, the output module outputs an abnormal loading state signal to the control system.

[0024] The wafer loading state detection device provided by the present invention has a preset value which is a ratio constant of the initial capacitance of the touch capacitor to the capacitance of the sampling capacitor. When the capacitance of the touch capacitor changes, the increment ΔC of the current capacitance of the touch capacitor compared to the initial capacitance of the touch capacitor is x The comparison module can quickly and accurately identify the situation where the frequency ratio increases, thereby improving the sensitivity of the device.

[0025] In an optional embodiment, the self-capacitance touch sensor also includes: a standard voltage / standard current output module, whose input end is connected to an external power supply, and whose output end is respectively connected to the input ends of the sampling capacitor oscillation module and the touch capacitor oscillation module, which is used to provide the same standard voltage and standard current for the sampling capacitor oscillation module and the touch capacitor oscillation module.

[0026] In the wafer loading state detection device provided by the present invention, the standard voltage / standard current output module can provide the same oscillation conditions for the sampling capacitor oscillation module and the touch capacitor oscillation module, thereby reducing interference during the oscillation process. When there is external interference or external power supply fluctuations, the oscillation curves output by the sampling capacitor oscillation module and the touch capacitor oscillation module fluctuate in the same manner. This ensures that the preset value obtained by the comparison module based on the sampling capacitor oscillation frequency and the touch capacitor oscillation frequency is only related to the capacitance of the touch capacitor and the sampling capacitor, thereby improving the accuracy of the detection results of the device.

[0027] In an optional embodiment, the elastic device includes a plurality of return springs, the first end of each return spring is connected to the first surface of the self-capacitive touch sensor, and the second end of each return spring is connected to the first surface of the insulating touch plate; the return spring is used to prevent the first surface of the insulating touch plate from contacting the second surface of the self-capacitive touch sensor when the wafer is normally loaded on the second surface of the airbag.

[0028] The wafer loading state detection device provided by the present invention has a reset spring that can isolate the first surface of the insulating touch plate from the second surface of the self-capacitive touch sensor by a certain distance, and the spring will only contract when a certain pressure is applied to one end of the spring, ensuring that when the wafer is normally loaded on the second surface of the airbag, causing the first surface of the airbag to be slightly deformed, the spring will not contract due to the slight deformation pressure of the airbag, so that the first surface of the insulating touch plate and the second surface of the self-capacitive touch sensor remain in an isolated state, avoiding false triggering of the self-capacitive touch sensor, improving the reliability of the device, and the spring has the advantage of low cost.

[0029] In the second aspect, the present invention provides a polishing device, comprising: a control system, a driving device, a polishing head, an airbag and the wafer loading status detection device of the first aspect, wherein the self-capacitance touch sensor, the elastic device, the insulating touch panel and the airbag are all arranged inside the polishing head; a driving device, a first end of which is connected to the control system, and a second end of which is connected to the first end of the polishing head, which drives the polishing head to polish the wafer based on the driving signal of the control system; a polishing head, which loads or unloads the wafer based on the control signal of the control system; when the wafer is normally loaded on the second surface of the airbag, the control system outputs a driving signal to the driving device based on the normal loading status signal, thereby controlling the polishing head to polish the wafer; when the wafer is not loaded on the second surface of the airbag or the loading status is abnormal, the control system stops outputting the driving signal to the driving device based on the abnormal loading status signal, thereby controlling the polishing head to stop polishing the wafer.

[0030] The polishing device provided by the present invention first detects whether the wafer is normally loaded on the polishing head through a self-capacitance touch sensor, and the detection process has low requirements for the air tightness of the polishing device; when it is judged that the wafer is normally loaded, the driving device is controlled to polish the wafer; if the self-capacitance touch sensor detects that the wafer is not loaded or the loading state is abnormal, the control system controls the driving device to stop polishing the wafer, thereby avoiding the driving device from working ineffectively and causing damage to other components of the polishing device, thereby improving the reliability and service life of the polishing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a specific structural diagram of a wafer loading status detection device in the related art;

[0033] Figure 2 is a composition diagram of a specific example of a wafer loading state detection device according to an embodiment of the present invention;

[0034] Figure 3 is a composition diagram of another specific example of a wafer loading state detection device according to an embodiment of the present invention;

[0035] Figure 4 FIG. 1 is a composition diagram of another specific example of a wafer loading state detection device according to an embodiment of the present invention;

[0036] Figure 5 FIG. 1 is a diagram showing a configuration of a specific example of a polishing apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0040] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] In the related art, the wafer loading status monitoring device determines the loading status of the wafer on the airbag by detecting the holding pressure of the air chamber through a mechanical structure in conjunction with an upper pressure control unit, such as Figure 1 As shown, when a wafer is loaded onto the airbag, the air chamber connected to the air valve is in a pressurized state, while the airbag in contact with the wafer is in a vacuum state. At this point, the airbag's back membrane convexes to a certain degree, and the air pressure causes the airbag to attract the wafer. If wafer adsorption is normal during this process, the degree of convexity of the airbag's back membrane is insufficient for the plunger to compress the spring and open the air valve. The holding pressure of the air chamber connected to the valve exceeds the judgment threshold, and the system determines that the wafer loading status is normal. If wafer adsorption is abnormal or not adsorbed during this process, the degree of convexity of the airbag's back membrane increases, and the plunger compresses the spring to open the air valve, releasing pressure in the air chamber connected to the valve. The holding pressure of the air chamber falls below the judgment threshold, and the system determines that the wafer loading status is abnormal. Since the air valve connecting the air chamber must maintain a pressure-maintaining state in any non-polishing working condition after the wafer loading is completed to judge the wafer loading status, air leakage is inevitable in the air path system. The detection results are greatly affected by the air tightness of the device and are prone to misjudgment. Therefore, a wafer loading status detection device is needed that is not affected by the air tightness of the device and has accurate detection results.

[0042] This embodiment provides a wafer loading status detection device, such as Figure 2As shown, it includes: a self-capacitive touch sensor 1, an elastic device 2 and an insulating touch plate 3, wherein the self-capacitive touch sensor 1 has a first surface connected to the input end of the control system, and a second surface connected to the first end of the elastic device 2; the elastic device 2 has a second end connected to the first surface of the insulating touch plate 3; the insulating touch plate 3 has a second surface in contact with the first surface of the airbag 4; the airbag 4 has a second surface for loading wafers, and the wafers are loaded on the second surface of the airbag 4 by evacuating the airbag 4.

[0043] Figure 2 In the embodiment, when the wafer is not loaded on the second surface of the airbag 4 or the wafer loading state is abnormal, the first surface of the airbag 4 bulges toward the second surface of the insulating touch plate 3 based on the air pressure, pushing the insulating touch plate 3 to shrink the elastic device 2, and the first surface of the insulating touch plate 3 contacts the second surface of the self-capacitive touch sensor 1. The self-capacitive touch sensor 1 determines that the insulating touch plate 3 touches the self-capacitive touch sensor 1 and sends a loading state abnormality signal to the control system.

[0044] Specifically, Figure 2 When a wafer is loaded onto the second surface of airbag 4, the air chamber of airbag 4 is in a vacuum state. Under the action of the vacuum, the second surface of airbag 4 adsorbs the wafer under the action of air pressure. When the wafer is normally loaded onto the second surface of airbag 4, the wafer supports the second surface of the airbag, causing the first surface of airbag 4 to barely deform, or the deformation of the first surface of airbag 4 is insufficient to overcome the pressure of elastic device 2. That is, the first surface of airbag 4 barely bulges toward the second surface of insulating touch panel 3, or the bulge of the first surface of airbag 4 is insufficient to overcome the deformation pressure of elastic device 2. Due to the support of elastic device 2, the first surface of insulating touch panel 3 does not come into contact with the second surface of self-capacitive touch sensor 1. Self-capacitive touch sensor 1 determines that no touch has occurred and sends a normal wafer loading status signal to the control system.

[0045] Specifically, Figure 2 In the embodiment, when the wafer is not loaded on the second surface of the airbag 4 or the wafer loading state is abnormal, since the second surface of the airbag 4 has no support from the wafer, the first surface of the airbag 4 is deformed under the action of air pressure, and the first surface of the airbag 4 bulges toward the second surface of the insulating touch plate 3, and overcomes the deformation pressure of the elastic device 2, pushing the insulating touch plate 3, so that the first surface of the insulating touch plate 3 contacts the second surface of the self-capacitive touch sensor 1, and the self-capacitive touch sensor 1 sends a wafer loading state abnormality signal to the control system.

[0046] It should be noted that technical personnel in this field need to select an elastic device with appropriate deformation pressure based on the degree of deformation of the airbag when the wafer is loaded abnormally, to ensure that when the wafer is loaded abnormally, the degree of deformation of the airbag can overcome the deformation pressure of the elastic device and push the insulating touch plate to contact the sub-capacitive touch sensor.

[0047] The self-capacitive touch sensor provided in this embodiment determines whether the first surface of the airbag is deformed by judging whether its second surface is in contact with the first surface of the insulating touch plate, and further determines the loading state of the wafer on the second surface of the airbag. Compared with the method in the related art of judging the loading state of the wafer by detecting the size of the holding pressure of the air chamber, the detection result of the present invention is almost independent of the airtightness of the device, the sensitivity is not affected by the experience and proficiency of the assembly workers, and is independent of the assembly error of the device, and has high detection accuracy and reliability.

[0048] Alternatively, as Figure 2 As shown, the elastic device 2 includes a plurality of return springs arranged at different positions, the first end of each return spring is connected to the first surface of the self-capacitive touch sensor 1, and the second end of each return spring is connected to the first surface of the insulating touch plate 3; the return spring is used to prevent the first surface of the insulating touch plate 3 from contacting the second surface of the self-capacitive touch sensor 1 when the wafer is normally loaded on the second surface of the airbag 4.

[0049] In some optional embodiments, such as Figure 3 As shown, the self-capacitive touch sensor includes: a capacitance oscillation module 11, a comparison module 12, an output module 13 and a touch electrode 14, wherein the capacitance oscillation module 11 has its input end connected to the external power supply, and its output end is connected to the input end of the comparison module 12. Its first end is the second surface of the self-capacitive touch sensor, which is based on the voltage and current of the external power supply through its internal sampling capacitor C s The electrical signal in the acquisition circuit is output and the sampling capacitor oscillation frequency is output, and the touch capacitor C x Output touch capacitance oscillation frequency, touch capacitance C x After the capacitance value thereof is changed based on the contact state between the insulating touch panel 3 and the first end of the capacitance oscillation module 11 , the capacitance oscillation module 11 adjusts the magnitude of the touch capacitance oscillation frequency.

[0050] like Figure 3As shown, the comparison module 12, whose output end is connected to the input end of the output module 13, is used to calculate the frequency ratio of the sampling capacitor oscillation frequency to the touch capacitor oscillation frequency, and then compare the frequency ratio with a preset value; the output module 13, whose output end is connected to the input end of the control system. The touch electrode 14, whose first surface is connected to the second surface of the self-capacitive touch sensor (i.e., the first end of the capacitor oscillation module 11), and whose second surface is connected to the first end of the elastic device 2, changes the touch capacitance C based on the contact state between the insulating touch plate 3 and the touch electrode 14. x After the capacitance value is set, the oscillation frequency of the touch capacitor is adjusted to maintain the oscillation frequency of the sampling capacitor unchanged.

[0051] Figure 3 When the wafer is normally loaded on the second surface of the airbag 4, the insulating touch panel 3 does not contact the first end of the capacitor oscillation module 11, and the touch capacitance C of the capacitor oscillation module 11 x The capacitance value remains unchanged. When the comparison module 12 determines that the frequency ratio is equal to the preset value, the output module 13 outputs a normal loading state signal to the control system; when the wafer is not loaded on the second surface of the airbag 4 or the loading state is abnormal, the insulating touch panel 3 contacts the first end of the capacitor oscillation module 11, and the touch capacitance C of the capacitor oscillation module 11 is x The capacitance value increases. When the comparison module 12 determines that the frequency ratio is not equal to the preset value, the output module 13 outputs a loading state abnormality signal to the control system.

[0052] Specifically, if Figure 3 As shown, the capacitor oscillation module includes a sampling capacitor C s And touch capacitance C x , the capacitor oscillation module 11 is connected to the sampling capacitor C s The electrical signal in the sampling circuit is collected and the sampling capacitor oscillation frequency is output. The capacitor oscillation module 11 also touches the capacitor C x Output touch capacitance oscillation frequency. When the insulating touch panel 3 contacts the touch electrode 14, the charge in the insulating touch panel 3 is transferred to the capacitance oscillation module 11 through the touch electrode 14. The touch capacitance C in the capacitance oscillation module 11 x After the capacitance value is changed based on the electrical signal and touch pressure, the size of the touch capacitance oscillation frequency output by the capacitance oscillation module 11 is changed. The comparison module 12 calculates the frequency ratio of the sampling capacitance oscillation frequency and the touch capacitance oscillation frequency, and determines that the frequency ratio is different from the preset value, that is, it is determined that the wafer is not loaded on the second surface of the airbag 4 or the loading state is abnormal, and sends the loading state abnormal signal to the control system through the output module 13.

[0053] In some optional embodiments, such as Figure 4As shown, the self-capacitive touch sensor further includes: a standard voltage / standard current output module 15, and a capacitance oscillation module including: a sampling capacitance oscillation module 111 and a touch capacitance oscillation module 112, wherein the sampling capacitance oscillation module 111 has its input end connected to the external power supply through the standard voltage / standard current output module 15, and its output end is connected to the input end of the comparison module 12, which outputs the sampling capacitance oscillation frequency f based on the voltage and current of the external power supply. s The touch capacitance oscillation module 112 has an input end connected to the external power supply through the standard voltage / standard current output module 15, an output end connected to the input end of the comparison module 12, and a first end connected to the first surface of the touch electrode 14. The touch capacitance oscillation frequency f is output based on the voltage and current of the external power supply. x , which adjusts the touch capacitance oscillation frequency f after the capacitance value is changed based on the contact state between the insulating touch panel 3 and the touch electrode 14 x The standard voltage / standard current output module 15 is used to provide the same standard voltage and standard current to the sampling capacitor oscillation module 111 and the touch capacitor oscillation module 112.

[0054] like Figure 4 As shown, the comparison module 12 calculates and obtains the sampling capacitor oscillation frequency f s and the touch capacitance oscillation frequency f x After the frequency ratio is obtained, the ratio is compared with the preset value; when the comparison module 12 determines that the frequency ratio is equal to the preset value, the output module 13 outputs a normal loading state signal to the control system; when the comparison module 12 determines that the frequency ratio is not equal to the preset value, the output module 13 outputs an abnormal loading state signal to the control system.

[0055] Specifically, if Figure 4 As shown, the sampling capacitor oscillation module 111 includes a sampling capacitor C s The touch capacitor oscillation module 112 includes a touch capacitor C x ; Standard voltage / standard current output module 15 is used based on the external power supply voltage and current, for the sampling capacitor C s And touch capacitance C x Provide the same standard voltage and standard current, that is, after charging the capacitors in the sampling capacitor oscillation module 111 and the touch capacitor oscillation module 112, the sampling capacitor C in the sampling capacitor oscillation module 111 s The sampling capacitor oscillation frequency f output after oscillation s for:

[0056]

[0057] Among them, V erf is the external power supply voltage, I ref is the external power supply current.

[0058] The touch capacitor C in the touch capacitor oscillation module 112 x The touch capacitance oscillation frequency f output after oscillation x for:

[0059]

[0060] The comparison module 12 calculates the input sampling capacitor oscillation frequency f s and the touch capacitance oscillation frequency f x Frequency ratio:

[0061]

[0062] Due to the existence of the standard voltage / standard current output module 15, the voltage V applied to the sampling capacitor oscillation module 111 and the touch capacitor oscillation module 112 is erf With current I ref consistent, so the sampling capacitor oscillation frequency f s and the touch capacitance oscillation frequency f x The frequency ratio is simplified to:

[0063]

[0064] Among them, C0 is the initial capacitance of the touch capacitor; A is the difference between C0 and C s The ratio of ΔC x = is the increment of the current touch capacitance compared to the initial capacitance of the touch capacitance. s The capacitance value remains unchanged, then A is a constant ratio and A is a preset value.

[0065] Figure 4 When the comparison module 12 determines that the frequency ratio is equal to the ratio constant A, that is, the current touch capacitance C x The capacitance value of the touch capacitor is 0 compared to the initial capacitance value of the touch capacitor. x The capacitance value is still the initial capacitance value C0, indicating that the insulating touch panel 3 is not in contact with the touch capacitance oscillation module 112 through the touch electrode 14, that is, the second surface of the airbag 4 is not deformed, the wafer is normally loaded on the second surface of the airbag 4, and the output module 13 outputs a normal loading state signal to the control system; when the comparison module 12 determines that the frequency ratio is not equal to the ratio constant A, that is, the current touch capacitance C x The capacitance value is not equal to the initial capacitance value C0 of the touch capacitor. The touch capacitor C xThe capacitance value changes, indicating that the insulating touch panel 3 is in contact with the touch electrode 14, that is, the second surface of the airbag 4 is deformed, the wafer is not loaded on the second surface of the airbag 4 or the loading state is abnormal, and the output module 13 outputs a loading state abnormality signal to the control system.

[0066] Preferably, the self-capacitive touch sensor 1 is made of a material with a high dielectric constant, so that when a small amount of charge in the insulating touch plate 3 moves to the self-capacitive touch sensor 1, the touch capacitance C x The capacitance value can be greatly changed, which makes it easier for the self-capacitive touch sensor 1 to determine the size of the frequency ratio and the preset value, and more accurately determine the loading status of the wafer.

[0067] This embodiment provides a polishing device, such as Figure 5 As shown, it includes: a control system 5, a driving device 6, a polishing head 7, an airbag 4 and a wafer loading state detection device of the above embodiments and any optional implementation manner thereof, wherein the self-capacitive touch sensor 1, the elastic device 2, the insulating touch panel 3 and the airbag 4 are all arranged inside the polishing head 7; the driving device 6, a first end of which is connected to the control system 5, and a second end of which is connected to the first end of the polishing head 7, which drives the polishing head 7 to polish the wafer based on the driving signal of the control system 5; the polishing head 7 loads or unloads the wafer based on the control signal of the control system 5; when the wafer is normally loaded on the second surface of the airbag 4, the control system 5 outputs a driving signal to the driving device 6 based on the normal loading state signal, thereby controlling the polishing head 7 to polish the wafer; when the wafer is not loaded on the second surface of the airbag or the loading state is abnormal, the control system 5 stops outputting the driving signal to the driving device 6 based on the abnormal loading state signal, thereby controlling the polishing head 7 to stop polishing the wafer.

[0068] Specifically, if Figure 5 As shown, based on the drive signal from the control system 5, the drive device 6 drives the polishing head 7 to perform actions such as loading the wafer, pressing the wafer down for polishing, sucking the wafer from the polishing pad, rotating the wafer, and unloading the wafer. When the wafer loading status detection device determines that the wafer is normally loaded on the polishing head, the self-capacitive touch sensor 1 sends a normal wafer loading signal to the control system 5, and the control system 5 drives the drive device 6 to operate based on the normal loading status signal. When the wafer loading status detection device determines that the wafer loading status on the polishing head is abnormal, the self-capacitive touch sensor 1 sends an abnormal wafer loading signal to the control system 5, and the control system 5 controls the drive device 6 to stop operating based on the abnormal loading status signal.

[0069] It should be noted that the working principle and workflow of the wafer loading status detection device in this embodiment are consistent with those in the above embodiment and any optional implementation manner thereof, and will not be repeated here.

[0070] The polishing device provided in this embodiment first detects whether the wafer is normally loaded on the polishing head through a self-capacitance touch sensor, and the detection process has low requirements for the air tightness of the polishing device; when it is judged that the wafer is normally loaded, the driving device is controlled to polish the wafer; if the self-capacitance touch sensor detects that the wafer is not loaded or the loading state is abnormal, the control system controls the driving device to stop polishing the wafer, thereby avoiding the driving device from working ineffectively and causing damage to other components of the polishing device, thereby improving the reliability and service life of the polishing device.

[0071] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A wafer loading status detection device, characterized in that: include: Self-capacitive touch sensor, elastic device and insulating touch panel, wherein, a self-capacitive touch sensor, a first surface of which is connected to an input terminal of a control system, and a second surface of which is connected to a first end of the elastic device; an elastic device, a second end of which is connected to the first surface of the insulating touch panel; an insulating touch panel, a second surface of which contacts the first surface of the airbag; The airbag has a second surface for loading wafers, and the wafers are loaded onto the second surface of the airbag by evacuating the airbag; When the wafer is not loaded on the second surface of the airbag or the wafer loading state is abnormal, the first surface of the airbag bulges toward the second surface of the insulating touch panel based on air pressure, pushing the insulating touch panel to contract the elastic device, so that the first surface of the insulating touch panel contacts the second surface of the self-capacitive touch sensor. The self-capacitive touch sensor determines that the insulating touch panel and the self-capacitive touch sensor are in contact, and sends a loading state abnormality signal to the control system. The self-capacitive touch sensor includes: a capacitance oscillation module, a comparison module and an output module, wherein: a capacitance oscillation module, having an input end connected to an external power supply, an output end connected to the input end of the comparison module, a first end of which is the second surface of the self-capacitance touch sensor, and an internal sampling capacitor of the capacitance oscillation module. The capacitance oscillation module collects electrical signals in the circuit based on the voltage and current of the external power supply via the internal sampling capacitor and outputs a sampling capacitance oscillation frequency, and outputs a touch capacitance oscillation frequency via the internal touch capacitor. The capacitance oscillation module adjusts the touch capacitance oscillation frequency after the touch capacitor changes its capacitance based on the contact state between the insulating touch plate and the first end of the capacitance oscillation module; a comparison module, whose output end is connected to the input end of the output module, and is used to calculate the frequency ratio of the sampling capacitor oscillation frequency to the touch capacitor oscillation frequency, and then compare the frequency ratio with a preset value; an output module, the output end of which is connected to the input end of the control system; When the wafer is normally loaded on the second surface of the airbag, the insulating touch panel does not contact the first end of the capacitive oscillation module, and the capacitance of the touch capacitor of the capacitive oscillation module remains unchanged. When the comparison module determines that the frequency ratio is equal to a preset value, the output module outputs a normal loading status signal to the control system; When the wafer is not loaded on the second surface of the airbag or the loading state is abnormal, the insulating touch panel contacts the first end of the capacitive oscillation module, and the capacitance of the touch capacitor of the capacitive oscillation module increases. When the comparison module determines that the frequency ratio is not equal to the preset value, the output module outputs a loading state abnormality signal to the control system; The self-capacitive touch sensor further includes: a touch electrode, a first surface of which is connected to the second surface of the self-capacitive touch sensor, and a second surface of which is connected to the first end of the elastic device, wherein the capacitance oscillation module adjusts the oscillation frequency of the touch capacitance after changing the capacitance of the touch capacitance based on the contact state between the insulating touch plate and the touch electrode, and maintains the oscillation frequency of the sampling capacitance unchanged; The capacitance oscillation module includes: a sampling capacitance oscillation module and a touch capacitance oscillation module, wherein: a sampling capacitor oscillation module, whose input end is connected to the external power supply, whose output end is connected to the input end of the comparison module, and which outputs the sampling capacitor oscillation frequency based on the voltage and current of the external power supply; a touch capacitance oscillation module, having an input end connected to an external power supply, an output end connected to the input end of the comparison module, and a first end connected to the first surface of the touch electrode, outputting a touch capacitance oscillation frequency based on the voltage and current of the external power supply, and adjusting the touch capacitance oscillation frequency based on a change in capacitance value due to contact between the insulating touch panel and the touch electrode; After the comparison module calculates and obtains the frequency ratio of the sampling capacitor oscillation frequency to the touch capacitor oscillation frequency, the comparison module compares the ratio with the preset value; When the comparison module determines that the frequency ratio is equal to the preset value, the output module outputs a loading state normal signal to the control system; When the comparison module determines that the frequency ratio is not equal to the preset value, the output module outputs a loading state abnormality signal to the control system.

2. The wafer loading status detection device according to claim 1, characterized in that: The sampling capacitor oscillation frequency is: in, f s is the sampling capacitor oscillation frequency; C s is the capacitance of the sampling capacitor in the sampling capacitor oscillation module; V erf External power supply voltage ；I ref is the external power supply current; The touch capacitance oscillation frequency is: in, f x is the touch capacitance oscillation frequency; C x is the capacitance of the touch capacitor in the touch capacitor oscillation module.

3. The wafer loading status detection device according to claim 2, characterized in that: The frequency ratio calculation formula of the sampling capacitor oscillation frequency and the touch capacitor oscillation frequency is: in, C 0 is the initial capacitance of the touch capacitor; A for C 0 and C s The ratio of ∆ C x is the increment of the current touch capacitance compared to the initial touch capacitance.

4. The wafer loading status detection device according to claim 3, characterized in that: When the comparison module determines that the frequency ratio is equal to the ratio of the initial capacitance of the touch capacitor to the capacitance of the sampling capacitor, the output module outputs a normal loading state signal to the control system; When the comparison module determines that the frequency ratio is not equal to the ratio of the initial capacitance of the touch capacitor to the capacitance of the sampling capacitor, the output module outputs a loading state abnormality signal to the control system.

5. The wafer loading status detection device according to claim 1, characterized in that: The self-capacitive touch sensor further includes: A standard voltage / standard current output module, whose input end is connected to an external power supply, and whose output end is respectively connected to the input ends of the sampling capacitor oscillation module and the touch capacitor oscillation module, is used to provide the same standard voltage and standard current for the sampling capacitor oscillation module and the touch capacitor oscillation module.

6. The wafer loading status detection device according to claim 1, characterized in that: The elastic device includes a plurality of return springs, wherein a first end of each return spring is connected to the first surface of the self-capacitive touch sensor, and a second end of each return spring is connected to the first surface of the insulating touch plate; The return spring is used to prevent the first surface of the insulating touch panel from contacting the second surface of the self-capacitive touch sensor when the wafer is normally loaded on the second surface of the airbag.

7. A polishing device, characterized in that: include: A control system, a driving device, a polishing head, an airbag, and a wafer loading state detection device according to any one of claims 1 to 6, wherein: The self-capacitive touch sensor, the elastic device, the insulating touch plate and the airbag are all arranged inside the polishing head; a driving device, a first end of which is connected to the control system, a second end of which is connected to the first end of the polishing head, and which drives the polishing head to polish the wafer based on a driving signal from the control system; a polishing head that loads or unloads the wafer based on a control signal from a control system; When the wafer is normally loaded on the second surface of the airbag, the control system outputs a driving signal to the driving device based on the normal loading state signal, thereby controlling the polishing head to polish the wafer; When the wafer is not loaded on the second surface of the airbag or the loading state is abnormal, the control system stops outputting the driving signal to the driving device based on the loading state abnormality signal, thereby controlling the polishing head to stop polishing the wafer.

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