A detection method and detection device for a flexible membrane of a chemical mechanical polishing head

Abstract

The application discloses a kind of detection method and detection device for the flexible film of chemical mechanical polishing head, and detection method includes the following steps: S1, to be measured flexible film is installed in polishing head, and polishing head is inverted, and to be measured flexible film presents natural drooping state;S2, the height profile curve of the height where the bottom surface of hard retaining ring is obtained using sensor scanning;S3, the curve is converted into coordinate system, and the bottom surface of hard retaining ring is X horizontal axis, and the center of hard retaining ring is coordinate system 0 point;S4, to be measured flexible film is applied air pressure;S5, sensor obtains the height distance of multiple points on the outer contour of to be measured flexible film and sensor, and forms the curve with height distance as Y axis in the coordinate system in step S3;S6, the curve is compared with the curve of standard flexible film, and whether to be measured flexible film meets the requirement is judged.The application is inverted on machine base in polishing head, so that flexible film detection state is consistent with actual use state, and detection result is more accurate.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit chip manufacturing technology, and in particular relates to a detection method and device for a flexible film used in a chemical mechanical polishing head. Background Technology

[0002] In semiconductor integrated circuit chip manufacturing processes, planarization technology has become one of the indispensable key technologies. Chemical Mechanical Planarization (CMP) is currently the most effective and mature planarization technology. CMP equipment mainly uses a polishing head to pick up and transport the wafer onto a polishing pad, and the wafer surface is planarized through the combined action of mechanical friction and chemical reaction.

[0003] Chemical mechanical polishing (CMP) heads are a crucial component of CMP equipment. As the part that directly acts on the wafer, they directly affect the polishing effect and transmission efficiency. Commercially available CMP polishing heads typically consist of multiple chambers divided by a flexible diaphragm. Each chamber can be independently controlled via a gas path to apply pressure to the wafer for better polishing results. Therefore, the quality and assembly stability of the flexible diaphragm directly affect the final polishing quality.

[0004] During CMP (Chemical Motion Processing), the flexible membrane transmits pressure to the wafer. Its performance is affected by the polishing chemical environment, its own elasticity, lifespan, and structural dimensions, impacting the consistency of polishing results and the stability of the transmission. In the production of flexible membranes, the industry primarily uses destructive elasticity testing after mold removal. This method cannot reflect the actual quality of each flexible membrane, nor can it account for the impact of unstable production dimensions on the polishing head.

[0005] Typically, after disassembly and reassembly, the polishing head only performs an airtightness test on the chambers of each flexible membrane to confirm the stability of the pressurized pressure. However, this simple quality control operation cannot guarantee the lifespan of the flexible membrane, production quality, or assembly quality. A flexible membrane whose elastic deformation deviates from the standard product will directly lead to deviations in the polishing results, resulting in incalculable losses on the mass production line. Furthermore, since flexible membranes are usually made of silicone rubber, long-term operation in a chemical liquid environment can lead to aging, relaxation, and deformation, which also affects batch stability. Production lines typically have a strict cycle for replacing the flexible membrane to ensure production stability; however, this replacement of consumables consumes a significant amount of machine time, setup costs, and maintenance costs.

[0006] When the polishing head is naturally mounted on the machine, the flexible diaphragm cavity is under vacuum, with its surface facing upwards and adhering to the polishing head. During CMP operations, certain conditions require the flexible diaphragm to switch from vacuum to positive pressure. If this process takes too long, it can lead to system errors or cause the wafer to fly out of the polishing head due to insufficient pressure. Therefore, effectively detecting the duration of the vacuum-to-positive-pressure switch for a particular polishing head is crucial for its normal operation. In existing technologies, CMP equipment typically only monitors pressure changes within the flexible diaphragm. However, both the flexible diaphragm and the air pressure are compressible, making it impossible to accurately reflect whether the flexible diaphragm is actually in a state of deformation and expansion, often resulting in false alarms from pressure sensors. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention provides a method and device for detecting flexible films in chemical mechanical polishing heads. It can detect the effectiveness of flexible films in their natural state. The detection method is simple and effective, and the detection results are accurate.

[0008] The technical solution adopted by this invention to solve its technical problem is: a method for detecting flexible films in chemical mechanical polishing heads, comprising the following steps: S1, the flexible membrane to be tested is mounted on the polishing head through the hard retaining ring of the polishing head, and the polishing head is inverted so that the flexible membrane to be tested is in a natural drooping state; S2, using a sensor placed below the polishing head to scan and obtain the height profile curve of the bottom surface of the hard retaining ring; S3. Convert the curve obtained in step S2 into a coordinate system with the bottom surface of the rigid retaining ring as the horizontal X-axis and the center of the rigid retaining ring as the coordinate system 0 point. S4. Apply air pressure to the flexible membrane under test so that it expands and deforms, but does not cause it to fail. S5, the sensor acquires the height distance between multiple points on the outer contour of the flexible membrane to be tested and the sensor, and forms a curve with the height distance as the Y-axis in the coordinate system in step S3; S6. Compare the curve with the curve of the standard flexible membrane to determine whether the flexible membrane under test meets the requirements.

[0009] Furthermore, the applied air pressure in step S4 is 0.1~3 psi.

[0010] Furthermore, the following steps are included before step S2: S01, apply air pressure of 0.1~3psi to the flexible membrane under test so that the flexible membrane under test expands and deforms, but does not deform and fail. S02, the sensor acquires the first contour information in the diameter direction of the flexible membrane to be tested. The first contour information is based on the bottom surface of the rigid retaining ring as the X-axis and the center of the rigid retaining ring as the coordinate system 0 point. S03, the sensor rotates and changes the angle, or the polishing head rotates and changes the angle, the sensor acquires one or more second contour information on the diameter of the flexible film to be measured, the second contour information is based on the bottom surface of the rigid retaining ring as the X horizontal axis, the center of the rigid retaining ring as the coordinate system 0 point, and the first contour information and the second contour information are converted to the same coordinate system. S04. Compare the edge height coordinate difference between the first contour information and the second contour information, and determine whether the flexible membrane under test is tilted based on the coordinate difference.

[0011] Furthermore, the cross-section of the air cavity inside the polishing head is circular or annular, and the air source is connected to the air cavity so that the flexible membrane under test expands to form a spherical curved surface or expands to form an annular wavy curved surface.

[0012] Furthermore, in step S4, air pressure is applied to the flexible membrane under test using the air source inside the polishing head itself.

[0013] Furthermore, the standard flexible membrane is a brand-new flexible membrane that is mounted on the polishing head using a rigid retaining ring and with the polishing head inverted.

[0014] Furthermore, the sensor is a linear laser sensor to cover the diameter of the rigid retaining ring; or, A surface laser sensor is used to cover the lower surface of the area where the rigid retaining ring is located; or, It is a dot-matrix laser sensor used to translate and scan the diameter region of the flexible membrane and rigid retaining ring under test.

[0015] Furthermore, in step S6, the hard retaining rings match during the comparison to ensure that the comparison benchmarks are the same.

[0016] Furthermore, in step S6, the comparison object is the maximum offset of the feature value of the flexible membrane profile, and / or, the total deviation of the flexible membrane profile, and / or, the peak offset of the flexible membrane profile, and / or, the overall root mean square error of the flexible membrane profile, and / or, the average displacement of the flexible membrane profile.

[0017] This invention also discloses a method for detecting flexible films in chemical mechanical polishing heads, comprising the following steps: 1) The flexible membrane to be tested is mounted on the polishing head through the hard retaining ring of the polishing head, and the polishing head is inverted so that the flexible membrane to be tested is in a natural drooping state; 2) Establish a coordinate system with the bottom surface of the rigid retaining ring as the X-axis and the center of the rigid retaining ring as the 0 point of the coordinate system; 3) Apply air pressure to the flexible membrane under test so that it expands and deforms, but does not deform and fail. 4) Starting from the time of applying air pressure as t0, continue to apply air pressure until T2. The sensor scans the expanded and deformed flexible membrane under test in real time at a specific frequency, obtains the height distance between multiple points on the outer contour of the flexible membrane under test and the sensor, forms a curve with the height distance as the Y-axis in the coordinate system in step 2), and records the base value and peak value of the curve. 5) Retrieve the outer contour curve of the flexible membrane under test within each scanning frequency of the sensor, compare it with the peak value of the last applied air pressure time period, and record the earliest time when the same peak value appears as t1. 6) Calculate the difference between t1 and t0 to determine whether the time required for the flexible membrane under test to switch from a vacuum state to a positive pressure state meets the requirements.

[0018] Furthermore, in step 4), the time point at which the flexible membrane under test expands to a stable state is T1, and the flexible membrane under test is kept stable in this expanded state until time point T2, and the time interval between T2 and T1 is 0 or greater than 0; the scanning frequency of the sensor is 20-20000Hz.

[0019] Furthermore, in step 6), the difference between the time t1 and t0 consumed by the flexible membrane under test is compared with the difference between the time t1 and t0 consumed by the standard flexible membrane. If the difference is less than or equal to 0.5s, the flexible membrane under test is judged to have a qualified response; if the difference is greater than 0.5s, the flexible membrane under test is judged to have an unqualified response.

[0020] Furthermore, in step 4), the flexible membrane to be tested is first switched to a negative pressure state, and the time from the start of the switch from the negative pressure state to the positive pressure state is t0.

[0021] This invention also discloses a detection device for flexible films in chemical mechanical polishing heads, applied to the above-mentioned detection method, characterized in that it comprises: Base; The polishing head is connected to the top of the base and has a rigid retaining ring at the bottom for connecting the flexible membrane. It also has an air cavity inside that communicates with the flexible membrane. A sensor, located below the polishing head, is used at least to scan and acquire contour information of the flexible membrane and the rigid retaining ring; The judgment unit is used to compare the differences in contour information between the standard flexible membrane and the flexible membrane under test acquired by the sensor to determine whether the flexible membrane meets the requirements.

[0022] Furthermore, the polishing head has at least two annular air chambers inside, and the flexible membrane is connected to the bottom of the spacer between adjacent air chambers.

[0023] Furthermore, the sensor is a linear laser sensor; or, the sensor is a surface laser sensor; or, the sensor is a dot matrix laser sensor.

[0024] Furthermore, the polishing head is equipped with an air source for expanding the flexible membrane. This air source can achieve the contraction of the flexible membrane under negative pressure. The expansion and contraction of the flexible membrane is the deformation of the flexible membrane relative to the plane where the bottom surface of the rigid retaining ring is located.

[0025] Furthermore, the sensor is provided with a rotating device to drive the sensor to rotate circumferentially about the central axis of the rigid retaining ring; or, The polishing head is equipped with a rotating device for driving the polishing head to rotate circumferentially about the central axis of the hard retaining ring.

[0026] The beneficial effects of this invention are: 1) The polishing head is placed upside down on the base, so that the detection state of the flexible film matches the actual use state, and the detection results are more accurate; 2) The sensor performs contour detection, thereby parameterizing and calibrating the deformation state of the flexible film without damaging the flexible film; 3) The detection method is simple and can be performed offline or online, with low requirements for the detection environment; 4) The method of accurately detecting the time it takes for the flexible film of the polishing head to switch from a vacuum state to a positive pressure state and judging whether the response of the flexible film of the polishing head is qualified is simple and effective; 5) Using the polishing head itself as a reference, the flexible film can be detected, which can be used for mass production flexible film quality inspection as well as mass assembly polishing head quality inspection. Attached Figure Description

[0027] Figure 1 Cross-section of the detection device provided by the present invention Figure 1 At this time, the flexible membrane is in a state of positive pressure expansion.

[0028] Figure 2 Cross-section of the detection device provided by the present invention Figure 2 At this time, the flexible membrane is under negative pressure.

[0029] Figure 3 The three-dimensional detection device provided by the present invention Figure 1 .

[0030] Figure 4 The three-dimensional detection device provided by the present invention Figure 2 .

[0031] Figure 5 This is a schematic diagram comparing the curves of the flexible membrane under test and the standard flexible membrane in this invention.

[0032] Figure 6This is a comparative diagram of the first contour information curve and the second contour information curve in this invention. At this time, the rotation angle of the two contour information curves is 90°.

[0033] Among them, 1-base, 11-flange, 2-polishing head, 21-hard retaining ring, 22-air chamber, 23-spacer, 24-air source, 3-sensor, 4-flexible membrane. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions in 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] A detection device for a flexible membrane in a chemical mechanical polishing head includes a base 1, a polishing head 2 connected to the top of the base 1, a sensor 3 disposed below the polishing head 2, and a judgment unit.

[0036] The top of the base 1 is connected to an inverted flange 11, and the polishing head 2 is fixedly connected to the flange 11 according to the polishing state. That is to say, the polishing head 2 is used to connect the rigid retaining ring 21 of the flexible membrane 4 at the bottom.

[0037] The lower part of the polishing head 2 is provided with a rigid retaining ring 21 for connecting the flexible membrane 4. An air cavity 22 is provided inside the polishing head 2, which is connected to the flexible membrane 4. When positive or negative pressure is applied to the air cavity 22, the flexible membrane 4 will deform. In this embodiment, at least two annular air cavities 22 are provided inside the polishing head 2. A flexible membrane 4 is fixedly connected to the bottom of a spacer 23 between adjacent air cavities 22. The air cavity 22 is also connected to an air source 24, which can be located inside or outside the polishing head 2. In this embodiment, the air source 24 is located inside the polishing head 2. The air source 24 is used to expand the flexible membrane 4. Simultaneously, the air source 24 can achieve contraction of the flexible membrane 4 under negative pressure. Specifically, the expansion and contraction of the flexible membrane 4 refer to the deformation of the flexible membrane 4 relative to the plane containing the lower surface of the rigid retaining ring 21.

[0038] Sensor 3 is located inside the base 1, directly below the polishing head 2. It is used to scan and acquire the contour information of the flexible film 4 and the hard retaining ring 21. It can be a linear laser sensor, a surface laser sensor, or a dot matrix laser sensor.

[0039] To facilitate the detection of contour information at different angles, the sensor 3 can be configured as a rotatable sensor 3, that is, the sensor 3 is equipped with a rotating device. The rotating device is used to drive the sensor 3 to rotate circumferentially around the central axis of the rigid retaining ring 21. The rotating device can adopt the structure of the prior art, which will not be described in detail here.

[0040] Alternatively, a rotating device can be provided in the polishing head 2 to drive the polishing head 2 to rotate circumferentially around the central axis of the hard retaining ring 21. The rotating device can adopt the structure in the prior art, which will not be described in detail here.

[0041] The judgment unit compares the contour information of the standard flexible membrane and the flexible membrane under test acquired by sensor 3 to determine whether the flexible membrane meets the requirements. A method for testing flexible films used in chemical mechanical polishing heads includes the following steps: S1, the flexible membrane to be tested is mounted on the polishing head through the hard retaining ring of the polishing head, and the polishing head is inverted so that the flexible membrane to be tested is in a natural drooping state; The polishing head here is used on 300mm wafers; During the polishing process, the flexible film on the polishing head expands and presses down on the wafer. The pressure area is typically distributed in a circular pattern, and the mechanical uniformity of this circular distribution affects the uniformity of the wafer removal rate during polishing. When assembling the flexible film onto the polishing head, factors such as screw tightening uniformity and dimensional uniformity can lead to an uneven, circular distribution of the flexible film on the polishing head. Conventional measurement methods cannot accurately determine the dimensions of the flexible film. To determine whether the flexible film is tilted when mounted on the polishing head, the following steps are performed: S01, apply air pressure to the flexible membrane under test. The air pressure is 0.1~3 psi, preferably 0.1~1 psi. In this embodiment, 0.5 psi is used to cause the flexible membrane to expand and deform without causing deformation failure. Figure 1 As shown; Under this pressure, the deformation of the flexible membrane under test can be amplified, but it will not expand too much and cause damage; Specifically, the cross-section of the air cavity inside the polishing head is circular or annular, and the air source is connected to the air cavity so that the flexible membrane under test expands to form a spherical curved surface or expands to form an annular wavy curved surface. In this embodiment, the air cavity is two or more concentric rings, more specifically, the air cavity is three concentric rings, and the flexible membrane under test expands to form an annular wavy curved surface. S02, the sensor acquires the first contour information in the diameter direction of the flexible membrane to be tested. The first contour information is based on the bottom surface of the rigid retaining ring as the X-axis and the center of the rigid retaining ring as the coordinate system 0 point. S03, the sensor rotates and changes the angle, or the polishing head rotates and changes the angle, the sensor acquires one or more second contour information on the diameter of the flexible film to be measured, the second contour information is based on the bottom surface of the rigid retaining ring as the X horizontal axis, the center of the rigid retaining ring as the coordinate system 0 point, and the first contour information and the second contour information are converted to the same coordinate system. In this embodiment, the rotation angle of the sensor or polishing head is 90°, such as... Figure 3 , Figure 4 As shown; S04, compare the edge height coordinate difference between the first contour information and the second contour information, and determine whether the flexible membrane to be tested is tilted based on the coordinate difference; like Figure 6 As shown, the height feature values ​​of the edges of the first contour information curve and the second contour information curve are extracted. When the height difference at one end is opposite to that at the other end, it is considered that the flexible film of the polishing head is tilted. When the height difference is greater than 0.2mm, it can be determined that the assembly quality of the polishing head is unqualified.

[0042] S2, using a sensor placed below the polishing head to scan and obtain the height profile curve of the bottom surface of the hard retaining ring; The sensor can be a linear laser sensor, thus covering the diameter of the rigid retaining ring; or, The sensor can be a surface laser sensor, which can cover the lower surface of the area where the rigid retaining ring is located; or, The sensor can be a dot matrix laser sensor, which scans the distance from each point on the profile to the plane where the laser emitter of the sensor is located by a large number of dot lasers, thereby enabling translational scanning of the diameter area of ​​the flexible membrane and rigid retaining ring under test, with a translation range greater than 300mm. In this embodiment, a linear laser sensor is used, positioned directly below the polishing head at its center. The focal length is set so that the scanning range covers a diameter approximately 320mm across the lower surface of the polishing head. This scanning range covers the inner edge of the rigid retaining ring and a 300mm diameter flexible membrane, thus fully reflecting the positional relationship between the flexible membrane and the fixed rigid retaining ring. The laser sensor scan provides the height distance from a point on the measured contour to the laser sensor, ultimately forming... Figure 5 curve.

[0043] S3. Convert the curve obtained in step S2 into a coordinate system with the bottom surface of the rigid retaining ring as the horizontal X-axis and the center of the rigid retaining ring as the coordinate system 0 point. Due to unavoidable tilting, center deviation, and irregular expansion of the flexible film during assembly, there is no clear calibration point. Therefore, in this embodiment, the inner ring of the hard retaining ring on the polishing head is used as the center, and the plane of the hard retaining ring is used as the reference plane to establish a coordinate system, thereby accurately reflecting the exact positional relationship of the flexible film on the polishing head.

[0044] S4. Using the air source within the polishing head itself, air pressure (0.1~1 psi) is applied to the flexible membrane under test to cause it to expand and deform without causing it to fail. Figure 1 As shown; S5, the sensor acquires the height distance between multiple points on the outer contour of the flexible membrane to be tested and the sensor, forming a curve with the height distance as the Y-axis in the coordinate system in step S3; S6. Compare the curve with the curve of the standard flexible membrane to determine whether the flexible membrane under test meets the requirements. The standard flexible membrane here refers to a brand new flexible membrane that is mounted on the polishing head using a rigid retaining ring and with the polishing head inverted; The comparison objects here are the maximum offset of the feature values ​​of the flexible membrane profile, and / or the total deviation of the flexible membrane profile, and / or the peak offset of the flexible membrane profile, and / or the overall root mean square error of the flexible membrane profile, and / or the average displacement of the flexible membrane profile. Furthermore, during the comparison, the rigid retaining rings are matched, ensuring that the comparison benchmark is the same and the comparison is more accurate.

[0045] like Figure 5 As shown, if the peak deviation of the tested flexible membrane at 0.5 psi is greater than 5% of that of the standard flexible membrane, it is considered that the tested flexible membrane has failed in elasticity or has a problem with its elasticity quality at the factory.

[0046] Current quality inspections of polishing heads and flexible membranes only cover airtightness testing, which cannot confirm the qualified elastic properties of the flexible membrane without compromising its integrity. During the production of the flexible membrane, low molecular weight during die casting leads to low elasticity and large deformation. Statistical analysis shows that with increasing usage time, silicone rubber aging also causes increased deformation. Therefore, the disclosed technology in this embodiment can parameterize and effectively determine the usage condition of the flexible membrane and whether it meets the usage standards.

[0047] A method for testing flexible films used in chemical mechanical polishing heads includes the following steps: 1) The flexible membrane to be tested is mounted on the polishing head through the hard retaining ring of the polishing head, and the polishing head is inverted so that the flexible membrane to be tested is in a natural drooping state; 2) Establish a coordinate system with the bottom surface of the rigid retaining ring as the X-axis and the center of the rigid retaining ring as the 0 point of the coordinate system; 3) Apply air pressure to the flexible membrane under test to cause it to expand and deform, but without causing it to fail due to deformation, such as... Figure 1 As shown; 4) Taking the time of applying air pressure as t0, specifically, first switch the flexible membrane to a negative pressure state, such as... Figure 2 As shown, the time from the start of the switch from negative pressure to positive pressure is t0. The air pressure is continuously applied until T2. The sensor scans the expanding and deforming flexible membrane under test in real time at a specific frequency. In this embodiment, the specific frequency is 20-20000Hz, preferably 50-1000Hz. The height distance between multiple points on the outer contour of the flexible membrane under test and the sensor is obtained. A curve with the height distance as the Y-axis is formed in the coordinate system in step 2). The deformation of the flexible membrane is monitored in real time throughout the process, and each set of curves is recorded. The base value and peak value of the curve are also recorded. The time point at which the flexible membrane under test expands to a stable state is T1. The flexible membrane under test is kept stable in this expanded state until time point T2. The time interval between T2 and T1 is 0 or greater than 0. In this embodiment, T2 is 6 seconds after the start of the air pressure application time t0 to ensure that the air-inflated deformation of the flexible membrane under test is fully stable. 5) Retrieve the outer contour curve of the flexible membrane under test within each scanning frequency of the sensor, compare it with the peak value of the last applied air pressure time period, and record the earliest time when the same peak value appears as t1. 6) Calculate the difference between t1 and t0 to determine whether the time required for the flexible membrane under test to switch from a vacuum state to a positive pressure state meets the requirements; Specifically, the difference between the time t1 and t0 consumed by the flexible membrane under test is compared with the difference between the time t1 and t0 consumed by the standard flexible membrane. If the difference is less than or equal to 0.5s, the flexible membrane under test is judged to have a qualified response; if the difference is greater than 0.5s, the flexible membrane under test is judged to have a unqualified response.

[0048] By monitoring the pressure application time of the flexible membrane and the time difference between the flexible membrane reaching its current deformation, the deformation rate of the flexible membrane can be monitored, thereby parametrically monitoring or detecting whether the polishing head can deform normally and quickly.

[0049] The above specific embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for detecting flexible films in chemical mechanical polishing heads, characterized in that: Includes the following steps: S1, the flexible membrane to be tested is mounted on the polishing head through the hard retaining ring of the polishing head, and the polishing head is inverted so that the flexible membrane to be tested is in a natural drooping state; S2, using a sensor placed below the polishing head to scan and obtain the height profile curve of the bottom surface of the hard retaining ring; S3. Convert the curve obtained in step S2 into a coordinate system with the bottom surface of the rigid retaining ring as the horizontal X-axis and the center of the rigid retaining ring as the coordinate system 0 point. S4. Apply air pressure to the flexible membrane under test so that it expands and deforms, but does not cause it to fail. S5, the sensor acquires the height distance between multiple points on the outer contour of the flexible membrane to be tested and the sensor, and forms a curve with the height distance as the Y-axis in the coordinate system in step S3; S6. Compare the curve with the curve of the standard flexible membrane to determine whether the flexible membrane under test meets the requirements.

2. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: The applied air pressure in step S4 is 0.1~3 psi.

3. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: The following steps are included before step S2: S01, apply air pressure of 0.1~3psi to the flexible membrane under test so that the flexible membrane under test expands and deforms, but does not deform and fail. S02, the sensor acquires the first contour information in the diameter direction of the flexible membrane to be tested. The first contour information is based on the bottom surface of the rigid retaining ring as the X-axis and the center of the rigid retaining ring as the coordinate system 0 point. S03, the sensor rotates and changes the angle, or the polishing head rotates and changes the angle, the sensor acquires one or more second contour information on the diameter of the flexible film to be measured, the second contour information is based on the bottom surface of the rigid retaining ring as the X horizontal axis, the center of the rigid retaining ring as the coordinate system 0 point, and the first contour information and the second contour information are converted to the same coordinate system. S04. Compare the edge height coordinate difference between the first contour information and the second contour information, and determine whether the flexible membrane under test is tilted based on the coordinate difference.

4. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: The cross-section of the air cavity inside the polishing head is circular or annular. The air source is connected to the air cavity so that the flexible membrane under test expands to form a spherical curved surface or expands to form an annular wavy curved surface.

5. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1 or 4, characterized in that: The polishing head has its own air source. In step S4, the air source inside the polishing head is used to apply air pressure to the flexible membrane to be tested.

6. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: The standard flexible membrane is a brand-new flexible membrane that is mounted on the polishing head using a rigid retaining ring and with the polishing head inverted.

7. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: The sensor is a linear laser sensor to cover the diameter of the rigid retaining ring; or, A surface laser sensor is used to cover the lower surface of the area where the rigid retaining ring is located; or, It is a dot-matrix laser sensor used to translate and scan the diameter region of the flexible membrane and rigid retaining ring under test.

8. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: In step S6, the hard retaining rings must match during the comparison to ensure that the comparison benchmarks are the same.

9. The method for detecting flexible films in chemical mechanical polishing heads according to claim 1, characterized in that: In step S6, the comparison object is the maximum offset of the feature value of the flexible membrane profile, and / or, the total deviation of the flexible membrane profile, and / or, the peak offset of the flexible membrane profile, and / or, the overall root mean square error of the flexible membrane profile, and / or, the average displacement of the flexible membrane profile.

10. A method for detecting flexible films in chemical mechanical polishing heads, characterized in that, Includes the following steps: 1) The flexible membrane to be tested is mounted on the polishing head through the hard retaining ring of the polishing head, and the polishing head is inverted so that the flexible membrane to be tested is in a natural drooping state; 2) Establish a coordinate system with the bottom surface of the rigid retaining ring as the X-axis and the center of the rigid retaining ring as the 0 point of the coordinate system; 3) Apply air pressure to the flexible membrane under test so that it expands and deforms, but does not deform and fail. 4) Starting from the time of applying air pressure as t0, continue to apply air pressure until T2. The sensor scans the expanded and deformed flexible membrane under test in real time at a specific frequency, obtains the height distance between multiple points on the outer contour of the flexible membrane under test and the sensor, forms a curve with the height distance as the Y-axis in the coordinate system in step 2), and records the base value and peak value of the curve. 5) Retrieve the outer contour curve of the flexible membrane under test within each scanning frequency of the sensor, compare it with the peak value of the last applied air pressure time period, and record the earliest time when the same peak value appears as t1. 6) Calculate the difference between t1 and t0 to determine whether the time required for the flexible membrane under test to switch from a vacuum state to a positive pressure state meets the requirements.

11. The method for detecting flexible films in chemical mechanical polishing heads according to claim 10, characterized in that: In step 4), the time point when the flexible membrane under test expands to a stable state is T1. The flexible membrane under test is kept stable in this expanded state until time point T2. The time interval between T2 and T1 is 0 or greater than 0. The scanning frequency of the sensor is 20-20000Hz.

12. The method for detecting flexible films in chemical mechanical polishing heads according to claim 10, characterized in that: In step 6), the difference between the time t1 and t0 consumed by the flexible membrane under test is compared with the difference between the time t1 and t0 consumed by the standard flexible membrane. If the difference is less than or equal to 0.5s, the flexible membrane under test is judged to have a qualified response. If the difference is greater than 0.5s, the flexible membrane under test is judged to have an unqualified response.

13. The method for detecting flexible films in chemical mechanical polishing heads according to claim 10, characterized in that: In step 4), the flexible membrane to be tested is first switched to a negative pressure state, and the time from the start of the switch from the negative pressure state to the positive pressure state is t0.

14. A detection device for a flexible film in a chemical mechanical polishing head, applied to the detection method as described in any one of claims 1-13, characterized in that, include: Base; The polishing head is connected to the top of the base and has a rigid retaining ring at the bottom for connecting the flexible membrane. It also has an air cavity inside that communicates with the flexible membrane. A sensor, located below the polishing head, is used at least to scan and acquire contour information of the flexible membrane and the rigid retaining ring; The judgment unit is used to compare the differences in contour information between the standard flexible membrane and the flexible membrane under test acquired by the sensor to determine whether the flexible membrane meets the requirements.

15. The detection device for flexible films in chemical mechanical polishing heads according to claim 14, characterized in that: The polishing head has at least two annular air chambers inside, and the flexible membrane is connected to the bottom of the spacer between adjacent air chambers.

16. The detection device for flexible films in chemical mechanical polishing heads according to claim 14, characterized in that: The sensor is a linear laser sensor; or, the sensor is a surface laser sensor; or, the sensor is a dot matrix laser sensor.

17. The detection device for flexible films in chemical mechanical polishing heads according to claim 14, characterized in that: The polishing head is equipped with an air source for expanding the flexible membrane. Under negative pressure, the air source can shrink the flexible membrane. The expansion and shrinkage of the flexible membrane is the deformation of the flexible membrane relative to the plane where the bottom surface of the rigid retaining ring is located.

18. The detection device for flexible films in chemical mechanical polishing heads according to claim 14, characterized in that: The sensor is equipped with a rotating device to drive the sensor to rotate circumferentially about the central axis of the rigid retaining ring. Alternatively, the polishing head may be provided with a rotating device for driving the polishing head to rotate circumferentially about the central axis of the hard retaining ring.

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