A method for preventing sticking of a membrane for a CMP polishing head

Abstract

The application provides a diaphragm anti-adhesion method for a CMP polishing head, and relates to the technical field of diaphragm reinforcement. The application obtains characteristic information of the diaphragm in a target pressure area under a preset negative pressure working condition, judges whether the diaphragm has a first type of adhesion risk of being attached to other side wall surfaces due to excessive overall axial displacement according to a maximum displacement amount and a maximum occurrence position, and selects a first type of anti-adhesion measure for limiting the axial stroke of the diaphragm if the diaphragm has the first type of adhesion risk; and judges whether the diaphragm has a second type of adhesion risk of deformation intensification due to insufficient bending stiffness at the root according to a maximum bending strain value, and selects a second type of anti-adhesion measure for increasing the bending stiffness of the corner area if the diaphragm has the second type of adhesion risk. Through the acquisition of the deformation characteristic information of the diaphragm under the negative pressure working condition, the deformation mechanism of the diaphragm is identified and classified, and finally different processing modes are realized. The application realizes precise intervention on different deformation failure modes, optimizes the structure design, and guarantees the anti-adhesion effect.

Description

Technical Field

[0001] This invention relates to the field of diaphragm strengthening technology, and more particularly to a method for preventing diaphragm adhesion in CMP polishing heads. Background Technology

[0002] In semiconductor CMP processes, polishing heads typically employ a multi-zone pressure control structure, applying adjustable polishing pressure to different radial regions of the wafer through independent pressure chambers and flexible diaphragms. Each pressure zone forms a sealed cavity with a diaphragm and a rigid support structure, and the positive or negative pressure within the cavity is controlled by a gas path. The negative pressure state is often used for operations such as rapid diaphragm reset or wafer adsorption and release.

[0003] In existing CMP polishing head designs, the geometric dimensions between the diaphragm and the rigid structure in different pressure zones are often the same or approximate, failing to fully consider the differences in deformation characteristics caused by variations in location and diaphragm floating length in each region. Furthermore, existing designs lack proactive measures to limit diaphragm deformation, relying solely on the diaphragm's own stiffness and chamber structure. This fails to effectively address the problem of increased local floating dimensions caused by machining tolerances or assembly deviations. Consequently, when diaphragm adhesion occurs due to negative pressure, existing solutions employ a single or approximate structural approach. This "one-size-fits-all" solution not only makes it difficult to accurately pinpoint the root cause of adhesion but may also lead to over-design or ineffective measures, failing to achieve optimal anti-adhesion performance within limited design space. Summary of the Invention

[0004] This invention provides a method for preventing diaphragm adhesion in CMP polishing heads, which solves the problem of over-designed structure or ineffective measures that fail to achieve optimal anti-adhesion effect.

[0005] This invention provides a method for preventing diaphragm adhesion in CMP polishing heads, the method comprising: The characteristic information of the diaphragm in the target pressure zone under a preset negative pressure condition is obtained. The characteristic information includes at least the maximum displacement of the diaphragm, the maximum occurrence position, and the maximum bending strain value of the diaphragm in the bend region. Based on the maximum displacement and the maximum occurrence location, it is determined whether the diaphragm has a first-type adhesion risk of sticking to other sidewalls due to excessive overall axial displacement; when the first-type adhesion risk exists, a first-type anti-adhesion measure is selected; the first-type anti-adhesion measure is used to limit the axial travel of the diaphragm in the negative pressure direction; Based on the maximum bending strain value, it is determined whether the diaphragm has a second type of adhesion risk due to insufficient bending stiffness at the root, which leads to increased deformation. When the second type of adhesion risk exists, a second type of anti-adhesion measure is selected, which is used to increase the bending stiffness of the bend area.

[0006] In one possible implementation, acquiring the characteristic information of the diaphragm in the target pressure zone under a preset negative pressure condition includes: The negative pressure condition is applied to the target pressure zone, and displacement data of the diaphragm surface and strain data of the bend region are collected in the target pressure zone. The collected displacement data and strain data are processed to obtain the maximum displacement, the maximum occurrence location, and the maximum bending strain value.

[0007] In one possible implementation, determining whether the diaphragm has a risk of first-type adhesion to other sidewalls due to excessive overall axial displacement, based on the maximum displacement and the location of maximum occurrence, includes: Obtain the spacing value between the corresponding opposite sidewalls in the diaphragm before the negative pressure condition is applied; The maximum displacement is compared with the spacing value, and the presence of the first type of adhesion risk is determined based on the comparison result. Obtain the direction of negative pressure under the negative pressure condition, and set up multiple detection points on the diaphragm before applying the negative pressure condition; Multiple displacements of the multiple detection points are obtained in the direction of the negative pressure, and a displacement distribution curve is formed based on the multiple displacements; Based on the displacement distribution curve, the difference between the displacement of two adjacent detection points is compared with a preset distance threshold to determine whether there is a risk of the first type of adhesion.

[0008] In one possible implementation, determining whether the diaphragm has a second-type adhesion risk due to insufficient root bending stiffness caused by insufficient bending stiffness, based on the maximum bending strain value, includes: Obtain the allowable bending strain value of the diaphragm, and the maximum reference strain value of the non-angled region of the diaphragm; The maximum bending strain value is compared with the allowable bending strain value and the reference strain value to determine whether there is a risk of the second type of adhesion.

[0009] In one possible implementation, the first type of anti-adhesion measure includes: Increasing the radial dimension of the outer support leg of the support plate within the target pressure zone allows the outer support leg to contact and support the diaphragm earlier during diaphragm deformation, thereby shortening the suspension span of the diaphragm in the negative pressure direction; and / or A plurality of limiting protrusions are provided on opposite sidewalls of the diaphragm to provide mechanical obstruction and limit the continued upward movement of corresponding areas in the diaphragm.

[0010] In one possible implementation, increasing the radial dimension of the outer support leg of the support plate within the target pressure zone includes: Based on the displacement distribution curve, determine the range of the displacement on the displacement distribution curve that reaches the preset displacement threshold; Based on the range of the interval and the original position of the outer support, the required radial dimension of the outer support is increased.

[0011] In one possible implementation, the provision of a plurality of limiting protrusions on opposite sidewalls of the diaphragm includes: Multiple limiting protrusions with a height of 0.5mm to 1.5mm are provided on opposite sidewalls of the diaphragm, and the gap between adjacent limiting protrusions is not less than twice the width of the limiting protrusion itself.

[0012] In one possible implementation, the second type of anti-adhesion measure includes: A prism structure is provided in the corner region, which is continuously or discontinuously distributed along the circumference of the corner region. The prism structure is used to increase the flexural modulus of the section of the corner region.

[0013] In one possible implementation, the width of the prism structure is 1mm to 3mm, and the cross-sectional shape of the prism structure is any one of triangle, rectangle or trapezoid.

[0014] In one possible implementation, the method further includes: When it is determined that both the first type of adhesion risk and the second type of adhesion risk exist simultaneously, both the first type of anti-adhesion measures and the second type of anti-adhesion measures shall be implemented at the same time. The first deformation inhibition rate after implementing the first type of anti-adhesion measures and the second deformation inhibition rate after implementing the second type of anti-adhesion measures were obtained respectively. Based on the first deformation inhibition rate and the second deformation inhibition rate, the first type of anti-adhesion measures and the second type of anti-adhesion measures are adjusted.

[0015] This invention provides a method for preventing diaphragm adhesion in CMP polishing heads. During the detection process, the invention first acquires characteristic information of the diaphragm in the target pressure zone under a preset negative pressure condition. Based on the maximum displacement and the location of maximum occurrence, it determines whether the diaphragm has a first-type adhesion risk due to excessive overall axial displacement causing it to adhere to other sidewalls. If so, a first-type anti-adhesion measure is selected to limit the diaphragm's axial travel. Based on the maximum bending strain value, it determines whether the diaphragm has a second-type adhesion risk due to insufficient bending stiffness at the root, leading to accelerated deformation. If so, a second-type anti-adhesion measure is selected to increase the bending stiffness of the bend area. By acquiring the deformation characteristic information of the diaphragm under negative pressure conditions, the deformation mechanism of the diaphragm is identified and classified, ultimately achieving different treatment methods. This invention achieves precise intervention for different deformation failure modes, optimizes structural design, and ensures the effectiveness of anti-adhesion. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of a method for preventing diaphragm adhesion in a CMP polishing head according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the Head thin-film assembly structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the deformation state of chamber 4 after being subjected to negative pressure, as provided in an embodiment of the present invention. Figure 4 This is a schematic diagram showing the position of the support leg when the size is increased in the first type of anti-adhesion measure provided in the embodiments of the present invention; Figure 5 This is a schematic diagram showing the position of the protruding structure added in the first type of anti-adhesion measure provided in the embodiments of the present invention; Figure 6 This is a schematic diagram showing the position of the added prism structure in the second type of anti-adhesion measures provided in the embodiments of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0019] This invention provides a method for preventing diaphragm adhesion in CMP polishing heads. This method acquires and classifies the deformation characteristics of the diaphragm under negative pressure conditions, distinguishing two adhesion failure modes with different physical causes: the first type of adhesion risk, caused by excessive overall axial displacement leading to adhesion between the diaphragm and the opposite side wall, and the second type of adhesion risk, caused by insufficient bending stiffness at the root leading to aggravated deformation. Corresponding anti-adhesion measures are selected for different failure modes, achieving precise intervention in diaphragm deformation failure.

[0020] It should be noted that this embodiment uses a certain pressure zone of the CMP polishing head as the target pressure zone for illustration. However, those skilled in the art should understand that this method is also applicable to other pressure zones of the polishing head. The specific implementation method can be adjusted accordingly with reference to this embodiment, and this embodiment does not limit it.

[0021] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment of the invention provides a method for preventing diaphragm adhesion in a CMP polishing head. The method includes steps S101-S103.

[0022] S101. Obtain the characteristic information of the diaphragm in the target pressure zone under the preset negative pressure condition. The characteristic information includes at least the maximum displacement of the diaphragm, the maximum occurrence position, and the maximum bending strain value of the diaphragm in the bend area.

[0023] Specifically, this step aims to obtain deformation characteristic data of the diaphragm under negative pressure conditions, providing a data foundation for subsequent risk classification and identification. As in the background art, when a negative pressure is applied to a specific pressure zone (such as chamber 4) of the CMP polishing head, the diaphragm will undergo significant deformation due to the pressure difference between its two sides. This step detects the deformation of the diaphragm under a preset negative pressure condition, obtaining three core characteristic parameters: the maximum displacement of the diaphragm (characterizing the severity of the overall deformation), the location of maximum occurrence (characterizing the area where deformation is concentrated), and the maximum bending strain value of the diaphragm in the bend region (characterizing the stress and deformation at the root of the bend). These three characteristic parameters correspond to the criteria for determining two different adhesion failure modes, comprehensively reflecting the deformation state of the diaphragm. The preset negative pressure condition can be the rated negative pressure value that the CMP polishing head withstands during rapid diaphragm reset operations or wafer adsorption and release operations, and can be determined according to actual process requirements; this embodiment does not specifically limit this.

[0024] As one possible implementation, step S101 can be specifically implemented as steps S1011-S1012.

[0025] S1011. Apply negative pressure to the target pressure zone, collect displacement data of the diaphragm surface in the target pressure zone, and collect strain data of the bend area.

[0026] Specifically, a preset negative pressure condition is applied to the target pressure zone, creating a vacuum below atmospheric pressure. Under this negative pressure, the diaphragm deforms due to the pressure difference on both sides. During the application of negative pressure, a displacement detection device collects displacement data on the diaphragm surface, while a strain detection device collects strain data in the diaphragm's folded area. The displacement detection device can be a non-contact displacement sensor such as a laser displacement sensor, capacitive displacement sensor, or eddy current displacement sensor, or a contact displacement sensor, positioned outside or inside the target pressure zone to effectively detect the diaphragm's displacement. The strain detection device can be a resistance strain gauge or a fiber optic strain sensor, attached to the diaphragm's folded area surface to sense local strain in the folded area. Taking chamber 4 as an example, the upper floating dimension of the diaphragm in this chamber is several millimeters longer than the normal area. When a rated negative pressure (e.g., -80 kPa) is applied, the diaphragm will undergo significant deformation, and the corresponding displacement and strain data can be collected by the sensors.

[0027] S1012. Process the collected displacement and strain data to obtain the maximum displacement, the maximum location of occurrence, and the maximum bending strain value.

[0028] Specifically, the raw displacement and strain data collected in step S1011 are processed, including but not limited to preprocessing operations such as filtering and denoising, analog-to-digital conversion, and calibration calculation, as well as extracting the maximum value and its corresponding spatial location information from the processed data. The maximum displacement is the maximum displacement amplitude among all detection points on the diaphragm surface, reflecting the maximum deformation of the diaphragm under negative pressure conditions; the maximum occurrence location is the specific coordinate of the diaphragm corresponding to the maximum displacement; the maximum bending strain value is the maximum strain amplitude among all detection points in the diaphragm corner area, reflecting the maximum bending deformation borne by the corner root under negative pressure conditions. Taking a practical application as an example, after applying negative pressure to chamber 4, simulation or actual measurement shows that the maximum displacement of the diaphragm can reach 10mm-12mm, the maximum occurrence location appears in the axial central region of the diaphragm, and the maximum bending strain value in the corner area may reach more than 80% of the allowable value of the material. These data will be used as input parameters for subsequent risk assessment.

[0029] S102. Based on the maximum displacement and the location of the maximum occurrence, determine whether the diaphragm has a first-class adhesion risk due to excessive overall axial displacement and sticking to the opposite side wall. When there is a first-class adhesion risk, select the first-class anti-adhesion measure. The first-class anti-adhesion measure is used to limit the axial travel of the diaphragm in the direction of negative pressure.

[0030] Specifically, this step, based on the maximum displacement and maximum occurrence location obtained in step S101, determines whether the diaphragm faces a Class I adhesion risk. Class I adhesion risk refers to the risk that, under negative pressure, the diaphragm's overall axial displacement is too large, causing the diaphragm surface to directly contact the opposite wall (i.e., the chamber wall of the target pressure zone), and adhesion occurs due to vacuum adsorption or surface adhesion, preventing the chamber from establishing a stable negative pressure. For example, in the background art, when chamber 4 is subjected to negative pressure alone, the diaphragm, due to its excessively long floating dimension, floats significantly upwards under negative pressure, and its upper surface directly adheres to the inner wall of the upper side of the chamber, which falls under the Class I adhesion risk. This step determines whether the deformation amplitude has reached the wall spacing by using the maximum displacement, and simultaneously determines whether the deformation occurs in the mid-span region of the diaphragm (where deformation is mainly characterized by overall upward floating, distinct from root bending) by using the maximum occurrence location, thereby achieving accurate identification of the Class I adhesion risk. When this risk is determined to exist, the first type of anti-adhesion measure is selected. The core function of this type of measure is to limit the axial travel of the diaphragm in the direction of negative pressure, preventing the diaphragm displacement from exceeding the safety threshold and touching the opposite side wall. The direction of negative pressure refers to the direction of diaphragm deformation guided by negative pressure suction, that is, the direction in which the diaphragm moves from its initial position toward the side generating negative pressure.

[0031] As one possible implementation, step S102 can be specifically implemented as steps S1021-S1025.

[0032] S1021. Obtain the spacing value between the corresponding opposite sidewalls in the diaphragm before the negative pressure condition is applied.

[0033] Specifically, before applying negative pressure, i.e., in the initial state before the diaphragm deforms, the distance between the initial position of the diaphragm and the opposite wall (i.e., the chamber wall where the diaphragm moves towards and may adhere to under negative pressure) is obtained. This distance is the spacing value. This spacing value is an important reference parameter for determining whether the diaphragm will adhere to the opposite wall due to excessive displacement. Taking chamber 4 as an example, the distance between the diaphragm and the inner wall of the upper side of the chamber in the initial state is the floating space of the diaphragm. This spacing value can be obtained directly from the design drawings or through actual measurement. Since the upper floating dimension of the diaphragm in chamber 4 is a few millimeters longer than the normal area, its corresponding spacing value is also correspondingly larger. This provides a larger deformation margin for the diaphragm, but also increases the risk of adhesion.

[0034] S1022. Compare the maximum displacement with the spacing value, and determine whether there is a risk of first-class adhesion based on the comparison result.

[0035] Specifically, the maximum displacement obtained in step S1012 is compared with the spacing value obtained in step S1021. If the maximum displacement is close to or reaches the spacing value, it indicates that the deformation of the diaphragm is sufficient to cause the diaphragm surface to contact the opposite wall surface, indicating a first-type adhesion risk. As a specific determination method, when the maximum displacement reaches 80% to 100% of the spacing value, a first-type adhesion risk is determined to exist. For example, if the spacing value is 12 mm, when the detected maximum displacement reaches 9.6 mm (i.e., 80% of the spacing value), since the diaphragm is a flexible structure, it is very likely to further deform under continuous negative pressure until it completely adheres to the wall surface. At this point, a first-type adhesion risk should be determined. This percentage threshold can be adaptively adjusted according to the diaphragm material characteristics, the magnitude of the negative pressure, and the safety margin requirements. By directly comparing the maximum displacement with the spacing value, it is possible to quickly determine whether there is a risk of adhesion due to excessive axial displacement, providing a quantitative basis for selecting subsequent measures.

[0036] S1023. Obtain the direction of negative pressure under negative pressure conditions, and set up multiple detection points on the diaphragm before applying negative pressure.

[0037] Specifically, the direction of negative pressure application (i.e., the displacement direction of the diaphragm under negative pressure) is determined, and multiple detection points are pre-established on the diaphragm surface before applying the negative pressure. These detection points are distributed along the axial direction of the diaphragm (i.e., the direction of negative pressure application) and are used to monitor the displacement of the diaphragm at different positions. The multiple detection points can be established by marking points on the diaphragm surface or by pre-setting node positions in the simulation model. The number of detection points can be determined according to the size of the diaphragm and the required detection accuracy. For example, 10-30 detection points can be evenly spaced along the direction of negative pressure application on the diaphragm surface to obtain sufficient displacement data to reflect the complete deformation morphology of the diaphragm.

[0038] S1024. Obtain multiple displacements of multiple detection points in the direction of negative pressure, and form a displacement distribution curve based on the multiple displacements.

[0039] Specifically, after applying negative pressure, the displacement of multiple detection points established in step S1023 along the direction of negative pressure is measured, obtaining multiple displacement data. The position coordinates of each detection point are correlated with its corresponding displacement, forming a displacement distribution curve with the diaphragm's axial position as the abscissa and the displacement as the ordinate. This displacement distribution curve can intuitively reflect the deformation morphology of the diaphragm along the axial direction, including: the magnitude of displacement in each region of the diaphragm, the location of the displacement peak, and the uniformity of displacement distribution along the axial direction. For example, if the diaphragm undergoes overall upward deformation, its displacement distribution curve presents a single-peak arch shape with large displacement at the mid-span and small displacement at both ends; if the deformation is mainly concentrated in the bend area, the curve shows a local peak near the bend.

[0040] S1025. Based on the displacement distribution curve, the difference between the displacement of two adjacent detection points is compared with a preset distance threshold to determine whether there is a risk of first-class adhesion.

[0041] Specifically, based on the displacement distribution curve obtained in step S1024, the difference between the displacement of two adjacent detection points is calculated, and this difference is compared with a preset distance threshold. When the displacement difference between adjacent detection points is too large, it indicates that the diaphragm has undergone a rapid deformation change in that adjacent area, and there may be local overstretching or folding.

[0042] As a specific judgment logic: if the displacement difference between adjacent detection points is less than or equal to a preset distance threshold, it indicates that the overall displacement distribution of the diaphragm is uniform. In this case, the risk of adhesion can be determined by combining the comparison result of the maximum displacement and the spacing value in step S1022. If the displacement difference between adjacent detection points is greater than the preset distance threshold, it indicates that abrupt deformation has occurred in a local area of ​​the diaphragm, and it can be determined that the diaphragm has already come into contact with or is about to come into contact with the opposite wall in that area, indicating a first-type adhesion risk. The preset distance threshold can be determined based on the elastic modulus and thickness of the diaphragm material, with a typical value of 1mm-3mm. This step, through the analysis of the slope of the displacement distribution curve, can identify the critical state of contact between the diaphragm and the wall, providing a more accurate basis for determining the first-type adhesion risk.

[0043] In some embodiments, the present invention further defines the first type of anti-adhesion measures, specifically including steps S201-S202.

[0044] S201, please refer to Figure 4 Increase the radial dimension of the outer support foot of the support plate in the target pressure zone so that the outer support foot contacts and supports the diaphragm in advance during the diaphragm deformation process, thereby shortening the suspension span of the diaphragm in the direction of negative pressure.

[0045] Specifically, the inner support plate is a rigid structural component located on one side of the diaphragm in the CMP polishing head, used to provide reference support for the diaphragm. The outer support leg is a support structure protruding from the inner support plate towards the diaphragm, with a certain gap between its end and the diaphragm surface in the initial state. When a Class I adhesion risk is determined, the radial dimension of the outer support leg (i.e., the length of the outer support leg extending outward from the main body of the inner support plate) is increased, so that when the diaphragm deforms along the direction of negative pressure, the end of the outer support leg can contact the diaphragm surface earlier and form mechanical support. This support effect is equivalent to adding an intermediate fulcrum in the axial travel of the diaphragm, thereby shortening the unsupported span of the diaphragm in the direction of negative pressure (i.e., the unsupported free length of the diaphragm). After the unsupported span is shortened, the maximum deformation of the diaphragm under the same negative pressure will be significantly reduced, thereby preventing the diaphragm displacement from reaching the level of contact with the opposite side wall. Taking chamber 4 as an example, the upper floating dimension of the diaphragm in chamber 4 is about 13mm. By increasing the radial dimension of the outer support, the suspended span is shortened to 8mm-10mm, which can effectively limit the maximum upward displacement of the diaphragm and prevent it from sticking to the inner wall of the upper side wall.

[0046] As one possible implementation, step S201 can be specifically implemented as steps S2011-S2012.

[0047] S2011. Based on the displacement distribution curve, determine the range of the displacement on the displacement distribution curve that reaches the preset displacement threshold.

[0048] Specifically, based on the displacement distribution curve obtained in step S1024, the range corresponding to the displacement reaching a preset displacement threshold is identified along the axial direction of the diaphragm. The preset displacement threshold is a critical displacement value determined by multiplying the spacing value obtained in step S1021 by a safety factor; for example, 70% or 80% of the spacing value can be set as the preset displacement threshold. On the displacement distribution curve, continuous intervals with displacement greater than or equal to the preset displacement threshold are marked; this interval range represents the part of the diaphragm where deformation is most significant. This interval range indicates the axial position where the diaphragm requires additional support.

[0049] S2012, please refer to Figure 4 Based on the range and the original position of the outer support, increase the required radial dimension of the outer support.

[0050] Specifically, based on the relative relationship between the original position of the outer support leg (i.e., the projected position of the outer support leg end in the diaphragm axial direction) determined in step S2011 and the specified range, the radial dimension increase of the outer support leg is determined. Specifically, the end of the outer support leg is extended to the starting position of the range or its adjacent area, so that the outer support leg can provide contact support when the diaphragm deforms to the specified range. This support is equivalent to adding limiting points in the critical area of ​​diaphragm deformation, effectively limiting the maximum displacement of the diaphragm within a preset displacement threshold. As an optional implementation, the typical value of the increased radial extension length of the outer support leg is 5mm-8mm. This size range provides effective mechanical support without affecting the normal normal deformation of the diaphragm under positive pressure conditions due to excessive extension of the outer support leg.

[0051] S202, please refer to Figure 5 Several limiting protrusions are provided on the opposite sidewalls of the diaphragm to provide mechanical obstruction and limit the continued upward movement of the corresponding area in the diaphragm.

[0052] Specifically, the opposite sidewall of the diaphragm refers to the surface of the diaphragm that faces the opposite sidewall when the diaphragm deforms towards it under negative pressure. Several limiting protrusions are provided on this opposite sidewall (i.e., the surface of the diaphragm), protruding a certain height from the diaphragm surface. When the diaphragm deforms towards the opposite sidewall to a preset stroke under negative pressure, the limiting protrusions first contact the opposite sidewall. The limiting protrusions bear the contact force between the diaphragm and the wall and provide mechanical resistance, thereby limiting the diaphragm's further upward movement. The setting of the limiting protrusions significantly reduces the actual contact area between the diaphragm and the opposite sidewall (changing from surface contact to point contact or local contact), while the supporting force of the protrusions themselves prevents the diaphragm from further deforming to a large-area adhesion state, effectively preventing adhesion.

[0053] As one possible implementation, step S202 can be specifically implemented as step S2021.

[0054] S2021, please refer to Figure 5 Multiple limiting protrusions with a height of 0.5mm to 1.5mm are provided on opposite sidewalls of the diaphragm, and the gap between adjacent limiting protrusions is not less than twice the width of the limiting protrusion itself.

[0055] Specifically, the height of the limiting protrusions is set within the range of 0.5mm to 1.5mm. This height range ensures that the protrusions contact the wall surface first and provide support when the diaphragm is about to adhere to the opposite wall surface, while preventing excessive height from occupying too much of the diaphragm's normal deformation space and affecting the uniformity of pressure transmission under positive pressure conditions. The cross-sectional shape of the limiting protrusions can be hemispherical, conical, or rectangular, etc. The gap between adjacent limiting protrusions is not less than twice the width of the limiting protrusion itself. This gap setting ensures that each protrusion can independently play a supporting role, while also maintaining sufficient channels between the protrusions to ensure smooth gas flow in the target pressure zone during negative pressure suction, avoiding obstruction of normal gas extraction due to overly dense protrusions. The limiting protrusions can be integrally formed with the diaphragm, or they can be attached to the diaphragm surface through subsequent bonding or thermoforming, depending on the diaphragm's manufacturing process.

[0056] S103, please refer to Figure 6 Based on the maximum bending strain value, it is determined whether the diaphragm has a second type of adhesion risk due to insufficient bending stiffness at the root, which leads to increased deformation. When a second type of adhesion risk exists, a second type of anti-adhesion measure is selected, which is used to increase the bending stiffness of the bend area.

[0057] Specifically, this step, based on the maximum bending strain value obtained in step S101, determines whether the diaphragm faces a second type of adhesion risk. The second type of adhesion risk refers to the situation where the diaphragm's corner area (i.e., the root turning point where the diaphragm extends from the rigid support structure) suffers from insufficient bending stiffness, resulting in excessive bending deformation under negative pressure. This alters the overall deformation state of the diaphragm, further increasing the risk of the diaphragm adhering to the opposite wall. For example, in the background art, when the diaphragm's floating length is around 13mm, its corner area bears a large bending moment under negative pressure. If the bending stiffness of the corner area is insufficient to resist this moment, excessive bending deformation will occur, causing the overall deformation of the diaphragm to change from "rigid floating" to "root bending," further increasing the possibility of the diaphragm adhering to the opposite wall. This step quantifies the stress level of the corner area using the maximum bending strain value. When the maximum bending strain value exceeds the material's allowable value or is significantly greater than the strain values ​​of other areas of the diaphragm, a second type of adhesion risk is determined to exist. When the risk is determined to exist, the second type of anti-adhesion measure is selected. The core function of this measure is to increase the bending stiffness of the corner area, so that the corner area is not prone to excessive bending when subjected to bending moment generated by negative pressure, thereby controlling the overall deformation of the diaphragm within a safe range.

[0058] As one possible implementation, step S103 can be specifically implemented as steps S1031-S1032.

[0059] S1031. Obtain the allowable bending strain value of the diaphragm, and the maximum reference strain value of the non-bend region in the diaphragm.

[0060] Specifically, the allowable bending strain value of the diaphragm material is obtained. This allowable bending strain value is the maximum strain that the diaphragm material can safely withstand under bending load. It is determined by the mechanical property parameters of the diaphragm material and can be obtained from a material handbook or determined through tensile / bending tests. Simultaneously, the maximum strain value of non-bending regions of the diaphragm (such as the mid-span region, edge region, etc.) is obtained as a reference strain value. This reference strain value reflects the strain level of the diaphragm under normal deformation (without root bending failure) and is used to compare with the maximum bending strain value of the bending region to determine whether the strain in the bending region is abnormally high.

[0061] S1032. Compare the maximum bending strain value with the allowable bending strain value and the reference strain value respectively to determine whether there is a risk of second-class adhesion.

[0062] Specifically, the maximum bending strain value of the bend region obtained in step S1012 is compared with the allowable bending strain value and the reference strain value obtained in step S1031. As a specific determination method: when the maximum bending strain value exceeds the allowable bending strain value, it indicates that the bending deformation of the bend region has exceeded the elastic bearing capacity of the material, and a second type of adhesion risk is identified. Alternatively, when the maximum bending strain value is significantly greater than the reference strain value (e.g., the maximum bending strain value is more than twice the reference strain value), it indicates that the strain level of the bend region is abnormally high, and the second type of adhesion risk is determined to be the dominant risk. The above two determination conditions can be used individually or in combination. By comparing the strain of the bend region with the allowable material value and the strain of the non-bend region, it is possible to accurately determine whether the bending deformation of the bend region is the dominant factor leading to increased diaphragm deformation, providing a quantitative basis for selecting second-type anti-adhesion measures.

[0063] In some embodiments, the present invention further defines the second type of anti-adhesion measures, specifically including step S301.

[0064] S301, please refer to Figure 6 In the corner region, prism structures are set up in a continuous or discontinuous manner along the circumference of the corner region. The prism structures are used to increase the flexural modulus of the section in the corner region.

[0065] Specifically, when a Class II adhesion risk is identified, a prismatic structure is installed in the corner region of the diaphragm. The prismatic structure is a stiffening rib-like structure installed in the corner region, extending circumferentially along the corner region. It can be a continuous ring-shaped prismatic structure or multiple prismatic segments spaced apart circumferentially. This prismatic structure effectively increases the flexural modulus (i.e., the section's ability to resist bending deformation) of the corner region by increasing its cross-sectional height or local thickness, thereby reducing the bending strain amplitude of the corner region under the same negative pressure conditions. Taking chamber 4 as an example, since the diaphragm floating length in this region is approximately 13mm, the corner region faces a large bending moment under negative pressure. By installing a prismatic structure in the corner region, the flexural stiffness of the corner region can be increased by 30%-50%, thus controlling the bending strain of the corner region within a safe range. The prismatic structure can be installed on the inner wall surface (inner surface of the diaphragm) or the outer wall surface (outer surface of the diaphragm) of the corner region, depending on the structural space and manufacturing process of the diaphragm.

[0066] Specifically, the width of the prism structure is 1mm to 3mm, and the cross-sectional shape of the prism structure is any one of triangle, rectangle or trapezoid.

[0067] Specifically, the width of the prism structure (i.e., the dimension of the prism along the axial direction of the diaphragm) is set within the range of 1mm to 3mm. This width provides sufficient cross-sectional reinforcement without significantly increasing the local stiffness of the diaphragm due to excessive prism width, thus affecting the pressure response characteristics of the diaphragm under positive pressure conditions. The cross-sectional shape of the prism structure can be any of triangular, rectangular, or trapezoidal shapes. The bending reinforcement effect varies slightly depending on the cross-sectional shape: triangular prisms have a gradual transition effect at the root of the bend, resulting in less stress concentration; rectangular prisms have the most significant reinforcement effect; and trapezoidal cross-sections combine the advantages of reinforcement and stress dispersion. The specific cross-sectional shape can be determined based on the stress distribution characteristics of the bend area and the manufacturing process; this embodiment does not limit this.

[0068] The present invention also provides an adjustment and optimization of the first type of anti-adhesion measure and the second type of anti-adhesion measure, including steps S401-S403.

[0069] S401. When it is determined that both the first type of adhesion risk and the second type of adhesion risk exist simultaneously, both the first type of anti-adhesion measures and the second type of anti-adhesion measures shall be implemented at the same time.

[0070] Specifically, when step S102 determines that there is a first type of adhesion risk and step S103 determines that there is a second type of adhesion risk, i.e., when both failure modes exist simultaneously, both the first and second type of anti-adhesion measures are executed simultaneously. "Simultaneous execution" includes both executing the two measures in parallel in time and simultaneously configuring the structural improvements corresponding to the two measures (such as both increasing the size of the outer support or adding limiting protrusions, and setting a prism structure in the corner area). Executing the two measures simultaneously allows for precise intervention for the two different failure modes: the first type of anti-adhesion measure is responsible for limiting the overall axial travel of the diaphragm to prevent the diaphragm from adhering to the opposite side wall; the second type of anti-adhesion measure is responsible for enhancing the bending stiffness of the corner area to prevent excessive deformation caused by excessive bending of the corner. The combined application of these two measures can achieve a synergistic effect—for example, increasing the size of the outer support legs provides support for the diaphragm from the bottom; and adding limiting protrusions provides lateral restraint for the diaphragm—thus forming a multi-layered anti-adhesion structure of "bottom support + lateral restraint + angle reinforcement," effectively improving the reliability of anti-adhesion. As a preferred embodiment, when both increasing the size of the outer support legs and adding limiting protrusions to the diaphragm surface are selected simultaneously, the outer support legs and limiting protrusions are staggered in the axial direction of the diaphragm to avoid mutual interference between their supporting effects.

[0071] S402. Obtain the first deformation inhibition rate after implementing the first type of anti-adhesion measures and the second deformation inhibition rate after implementing the second type of anti-adhesion measures.

[0072] Specifically, after implementing each anti-adhesion measure, the effect of each measure on suppressing diaphragm deformation is evaluated. The deformation suppression rate is defined as: (maximum displacement or maximum bending strain before implementation - maximum displacement or maximum bending strain after implementation) / maximum displacement or maximum bending strain before implementation × 100%. Specifically, for the first type of anti-adhesion measure, its first deformation suppression rate can be calculated by the change in maximum displacement before and after implementation; for the second type of anti-adhesion measure, its second deformation suppression rate can be calculated by the change in maximum bending strain before and after implementation. A higher deformation suppression rate indicates a more significant effect of the corresponding measure on suppressing diaphragm deformation. By calculating the deformation suppression rates of the two measures separately, the effectiveness of each measure under actual operating conditions can be quantitatively evaluated.

[0073] S403. Based on the first deformation inhibition rate and the second deformation inhibition rate, adjust the first type of anti-adhesion measures and the second type of anti-adhesion measures.

[0074] Specifically, based on the first and second deformation suppression rates obtained in step S402, the selected anti-adhesion measures are adaptively adjusted. If the deformation suppression rate of a certain measure is lower than the preset suppression rate threshold, it indicates that the suppression effect of the measure is insufficient, and the measure needs to be strengthened (such as further increasing the radial dimension of the outer support, increasing the height or density of the limiting protrusion, increasing the width of the prism structure, etc.) or supplemented with other auxiliary measures. If the deformation suppression rates of both measures have reached the preset suppression rate threshold, the current measure scheme is maintained. If the deformation suppression rate of a certain measure is much higher than expected, the strength of the measure can be appropriately reduced while ensuring the anti-adhesion effect, so as to avoid over-design that may adversely affect the normal working performance of the diaphragm (such as excessively large outer supports may limit the deformation space of the diaphragm under positive pressure). By adjusting the anti-adhesion measures based on measured data, the final structural configuration can achieve optimal design while meeting the anti-adhesion requirements.

[0075] Through the above steps, the present invention can adaptively select appropriate anti-adhesion measures based on the diaphragm deformation characteristics of different pressure zones in the CMP polishing head, effectively avoiding abnormal adhesion of the diaphragm under negative pressure, ensuring the independent control reliability and negative pressure establishment capability of each pressure zone in negative pressure suction mode, thereby improving the stability of the CMP process and the uniformity of wafer polishing.

[0076] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for preventing diaphragm adhesion in CMP polishing heads, characterized in that, include: The characteristic information of the diaphragm in the target pressure zone under a preset negative pressure condition is obtained. The characteristic information includes at least the maximum displacement of the diaphragm, the maximum occurrence position, and the maximum bending strain value of the diaphragm in the bend region. Based on the maximum displacement and the location of the maximum occurrence, it is determined whether the diaphragm has a first-type adhesion risk of sticking to other sidewalls due to excessive overall axial displacement; when the first-type adhesion risk exists, a first-type anti-adhesion measure is selected; the first-type anti-adhesion measure is used to limit the axial travel of the diaphragm in the direction of negative pressure. Based on the maximum bending strain value, it is determined whether the diaphragm has a second type of adhesion risk due to insufficient bending stiffness at the root, which leads to increased deformation. When the second type of adhesion risk exists, a second type of anti-adhesion measure is selected, which is used to increase the bending stiffness of the bend area.

2. The method for preventing diaphragm adhesion in a CMP polishing head according to claim 1, characterized in that, The acquisition of characteristic information of the diaphragm in the target pressure zone under a preset negative pressure condition includes: The negative pressure condition is applied to the target pressure zone, and displacement data of the diaphragm surface and strain data of the bend region are collected in the target pressure zone. The collected displacement data and strain data are processed to obtain the maximum displacement, the maximum occurrence location, and the maximum bending strain value.

3. The method for preventing diaphragm adhesion in a CMP polishing head according to claim 2, characterized in that, The step of determining whether the diaphragm has a risk of adhesion to other sidewalls due to excessive overall axial displacement, based on the maximum displacement and the location of maximum occurrence, includes: Obtain the spacing value between the corresponding opposite sidewalls in the diaphragm before the negative pressure condition is applied; The maximum displacement is compared with the spacing value, and the presence of the first type of adhesion risk is determined based on the comparison result. Obtain the direction of negative pressure under the negative pressure condition, and set up multiple detection points on the diaphragm before applying the negative pressure condition; Multiple displacements of the multiple detection points are obtained in the direction of the negative pressure, and a displacement distribution curve is formed based on the multiple displacements; Based on the displacement distribution curve, the difference between the displacement of two adjacent detection points is compared with a preset distance threshold to determine whether there is a risk of the first type of adhesion.

4. The method for preventing diaphragm adhesion in a CMP polishing head according to claim 2, characterized in that, The step of determining whether the diaphragm has a second-type adhesion risk due to insufficient bending stiffness at the root, based on the maximum bending strain value, includes: Obtain the allowable bending strain value of the diaphragm, and the maximum reference strain value of the non-angled region of the diaphragm; The maximum bending strain value is compared with the allowable bending strain value and the reference strain value to determine whether there is a risk of the second type of adhesion.

5. A method for preventing diaphragm adhesion in a CMP polishing head according to claim 3, characterized in that, The first type of anti-adhesion measures include: Increasing the radial dimension of the outer support leg of the support plate within the target pressure zone allows the outer support leg to contact and support the diaphragm earlier during diaphragm deformation, thereby shortening the suspension span of the diaphragm in the negative pressure direction; and / or A plurality of limiting protrusions are provided on opposite sidewalls of the diaphragm to provide mechanical obstruction and limit the continued upward movement of corresponding areas in the diaphragm.

6. A method for preventing diaphragm adhesion in a CMP polishing head according to claim 5, characterized in that, The increase in the radial dimension of the outer support leg of the support plate within the target pressure zone includes: Based on the displacement distribution curve, determine the range of the displacement on the displacement distribution curve that reaches the preset displacement threshold; Based on the range of the interval and the original position of the outer support, the required radial dimension of the outer support is increased.

7. A method for preventing diaphragm adhesion in a CMP polishing head according to claim 5, characterized in that, The provision of several limiting protrusions on opposite sidewalls of the diaphragm includes: Multiple limiting protrusions with a height of 0.5mm to 1.5mm are provided on opposite sidewalls of the diaphragm, and the gap between adjacent limiting protrusions is not less than twice the width of the limiting protrusion itself.

8. A method for preventing diaphragm adhesion in a CMP polishing head according to claim 1, characterized in that, The second type of anti-adhesion measures include: A prism structure is provided in the corner region, which is continuously or discontinuously distributed along the circumference of the corner region. The prism structure is used to increase the flexural modulus of the section of the corner region.

9. A method for preventing diaphragm adhesion in a CMP polishing head according to claim 8, characterized in that, The width of the prism structure is 1mm to 3mm, and the cross-sectional shape of the prism structure is any one of triangle, rectangle or trapezoid.

10. A method for preventing diaphragm adhesion in a CMP polishing head according to claim 1, characterized in that, The method further includes: When it is determined that both the first type of adhesion risk and the second type of adhesion risk exist simultaneously, both the first type of anti-adhesion measures and the second type of anti-adhesion measures shall be implemented at the same time. The first deformation inhibition rate after implementing the first type of anti-adhesion measures and the second deformation inhibition rate after implementing the second type of anti-adhesion measures were obtained respectively. Based on the first deformation inhibition rate and the second deformation inhibition rate, the first type of anti-adhesion measures and the second type of anti-adhesion measures are adjusted.

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