Grinding pad and method for adjusting elasticity modulus of grinding pad

Abstract

The invention relates to the technical field of optical machining tool manufacturing, and provides a grinding pad and an elastic modulus adjusting method of the grinding pad. The grinding pad comprises an elastic adjusting layer, a pressure sensing layer and a control layer; the pressure sensing layer is used for collecting pressure distribution information of the elastic adjusting layer and transmitting the pressure distribution information to the control layer; the control layer is used for determining the grinding pressure of each area of the elastic adjusting layer according to the pressure distribution information, generating a corresponding adjusting instruction according to the grinding pressure of each area of the elastic adjusting layer, and adjusting the elastic modulus of at least one area of the elastic adjusting layer according to the adjusting instruction, so that the pressure of the elastic adjusting layer is uniformly distributed; according to the grinding pad, the elastic modulus of the elastic adjusting layer is dynamically adjusted, the grinding pressure is evenly distributed on the surface of a grinding workpiece in the grinding process, then the grinding pad can adapt to the curved surface contour of a complex workpiece and the grinding requirements of different areas, and the surface shape precision of the grinding workpiece is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical processing tool manufacturing, and in particular to a polishing pad and a method for adjusting the elastic modulus of the polishing pad. BACKGROUND

[0002] Precision polishing is a key process in high-end manufacturing fields such as semiconductors and optical elements, and the surface accuracy and polishing efficiency of precision polishing directly affect product performance and production cost. With the increasing requirements of the industry for the processing accuracy of precision polishing, the processing accuracy of precision polishing is at the nanometer or even sub-nanometer level.

[0003] In related technologies, the polishing pad is made of a polymer material. In the polishing process, the surface pressure of the polishing pad is unevenly distributed, which is difficult to adapt to the complex surface profile of the workpiece and the polishing requirements of different areas, resulting in difficulty in ensuring the surface accuracy of the workpiece. SUMMARY

[0004] Therefore, the embodiments of the present application provide a polishing pad and a method for adjusting the elastic modulus of the polishing pad to solve the problem of uneven distribution of the surface pressure of the polishing pad in the polishing process in the prior art.

[0005] In a first aspect, the present application provides a polishing pad, comprising: an elastic adjustment layer, a pressure sensing layer, and a control layer; the pressure sensing layer is configured to collect pressure distribution information of the elastic adjustment layer and transmit the pressure distribution information to the control layer; the control layer is configured to determine polishing pressures of each region of the elastic adjustment layer according to the pressure distribution information, generate corresponding adjustment instructions according to the polishing pressures of each region of the elastic adjustment layer, and adjust the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions, so that the pressure of the elastic adjustment layer is uniformly distributed.

[0006] In a second aspect, the present application provides a method for adjusting the elastic modulus of a polishing pad, comprising: collecting pressure distribution information of an elastic adjustment layer during polishing of the elastic adjustment layer; determining polishing pressures of each region of the elastic adjustment layer according to the pressure distribution information, and generating corresponding adjustment instructions according to the polishing pressures of each region of the elastic adjustment layer; and adjusting the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions, so that the pressure of the elastic adjustment layer is uniformly distributed.

[0007] The beneficial effects of the embodiments of the present application compared with the prior art are: the grinding pad provided in the embodiments of the present application comprises an elastic adjusting layer, a pressure sensing layer and a control layer; the pressure sensing layer is used to collect the pressure distribution information of the elastic adjusting layer and transmit the pressure distribution information to the control layer; the control layer is used to determine the grinding pressure of each region of the elastic adjusting layer according to the pressure distribution information, generate corresponding adjusting instructions according to the grinding pressure of each region of the elastic adjusting layer, and adjust the elastic modulus of at least one region of the elastic adjusting layer according to the adjusting instructions, so that the pressure of the elastic adjusting layer is uniformly distributed. The grinding pad realizes dynamic adjustment of the elastic modulus of the elastic adjusting layer, so that the grinding pressure is uniformly distributed on the surface of the workpiece during the grinding process, and then the grinding pad can adapt to the curved surface profile of the complex workpiece and the grinding requirements of different regions, improves the surface shape precision of the workpiece, and avoids the problem of uneven distribution of surface pressure of the grinding pad in the prior art during the grinding process. BRIEF DESCRIPTION OF DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0009] Figure 1 is a basic schematic diagram of a grinding pad provided by the embodiments of the present application;

[0010] Figure 2 is a schematic diagram of an elastic modulus adjusting method of a grinding pad provided by the embodiments of the present application;

[0011] Figure 3 is a structural schematic diagram of an elastic modulus adjusting device of a grinding pad provided by the embodiments of the present application. DETAILED DESCRIPTION

[0012] In the following description, specific details such as specific system structures, techniques, etc. are presented in order to thoroughly understand the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, grinding pad elastic modulus adjusting methods, circuits and methods are omitted to avoid unnecessary details that hinder the description of the present application.

[0013] A grinding pad and a grinding pad elastic modulus adjusting method according to the embodiments of the present application will be described in detail below with reference to the drawings.

[0014] It can be understood that the elastic modulus is used to describe the ability of a material to resist deformation in the elastic deformation stage, and the larger the value is, the harder the material is, and the smaller the value is, the softer the material is. In the related art, the elastic modulus of the polishing pad surface cannot be dynamically adjusted in real time according to the pressure distribution, so that the polishing pressure cannot uniformly act on the surface of the workpiece polished by the polishing pad, and the surface shape precision of the workpiece is difficult to guarantee. For example, when polishing a curved optical element, because the elastic modulus of the polishing pad surface is fixed, the pressure on different curvature regions is different, which easily causes local over-polishing or under-polishing of the optical element, and seriously affects the surface shape precision of the optical element.

[0015] To avoid the above problems, the application provides a polishing pad, Figure 1 is a basic schematic diagram of a polishing pad provided by an embodiment of the application, as Figure 1 shown, the polishing pad comprises an elastic adjusting layer 101, a pressure sensing layer 102, and a control layer 103; the pressure sensing layer 102 is used to collect pressure distribution information of the elastic adjusting layer 101 and transmit the pressure distribution information to the control layer 103; the control layer 103 is used to determine the polishing pressure of each region of the elastic adjusting layer 101 according to the pressure distribution information, generate corresponding adjusting instructions according to the polishing pressure of each region of the elastic adjusting layer 101, and adjust the elastic modulus of at least one region of the elastic adjusting layer 101 according to the adjusting instructions, so that the pressure of the elastic adjusting layer 101 is uniformly distributed.

[0016] Wherein, one side of the elastic adjusting layer 101 is in contact with the workpiece, and is used to bear the external load from the workpiece and polish the workpiece. The pressure sensing layer 102 is arranged on the side of the elastic adjusting layer 101 away from the workpiece, and is used to sense the pressure distribution information borne by the surface of the elastic adjusting layer 101 in the polishing process in real time. The control layer 103 is connected with the pressure sensing layer 102, and is used to receive the pressure distribution information, determine the polishing pressure of each region of the elastic adjusting layer 101 according to the pressure distribution information, generate corresponding adjusting instructions according to the polishing pressure of each region of the elastic adjusting layer 101, and adjust the elastic modulus of at least one region of the elastic adjusting layer 101 according to the adjusting instructions, so that the pressure of the elastic adjusting layer 101 is uniformly distributed.

[0017] In the process of grinding the elastic adjustment layer 101, the pressure sensing layer 102 collects the pressure distribution information of the elastic adjustment layer 101 and transmits the pressure distribution information to the control layer 103, and the control layer 103 determines whether the pressure distribution of the elastic adjustment layer 101 is uniform (or whether it meets the expectation) through the pressure distribution information, and in the case where it is determined that the pressure distribution of the elastic adjustment layer 101 is not uniform, generates corresponding adjustment instructions according to the grinding pressure of each region of the elastic adjustment layer 101, and adjusts the elastic modulus of at least one region of the elastic adjustment layer 101 according to the adjustment instructions, so that the pressure of the elastic adjustment layer 101 forms a uniform distribution according to the demand.

[0018] According to the scheme provided by the embodiment of the application, the grinding pad comprises: an elastic adjustment layer 101, a pressure sensing layer 102, and a control layer 103; the pressure sensing layer 102 is configured to collect the pressure distribution information of the elastic adjustment layer 101 and transmit the pressure distribution information to the control layer 103; and the control layer 103 is configured to determine the grinding pressure of each region of the elastic adjustment layer 101 according to the pressure distribution information, generate corresponding adjustment instructions according to the grinding pressure of each region of the elastic adjustment layer 101, and adjust the elastic modulus of at least one region of the elastic adjustment layer 101 according to the adjustment instructions, so that the pressure of the elastic adjustment layer 101 is uniformly distributed. The grinding pad realizes dynamic adjustment of the elastic modulus of the elastic adjustment layer 101, so that the grinding pressure is uniformly distributed on the surface of the workpiece during grinding, and thus the grinding pad can adapt to the curved surface profile of the complex workpiece and the grinding requirements of different regions, improving the surface shape precision of the workpiece, and avoiding the problem of uneven distribution of surface pressure of the grinding pad in the prior art during grinding. Thus, the pressure adjustment of the demand surface type is achieved, and the ideal part surface type is quickly ground to the demand surface type.

[0019] In some examples, in order to realize fine control of the pressure on the surface of the elastic adjustment layer 101, preferably, the surface of the elastic adjustment layer 101 is divided into a plurality of pressure sensing regions, and a plurality of pressure sensing units are provided in the pressure sensing layer 102, each pressure sensing region corresponding to a pressure sensing unit, so as to realize independent monitoring and independent adjustment of the pressure of each region, improving the control accuracy and response speed.

[0020] It can be understood that the control layer 103 can also control each pressure sensing region individually, thereby adjusting the elastic modulus of each pressure sensing region of the elastic adjustment layer 101.

[0021] Preferably, high-precision, real-time, and regional perception of the surface pressure distribution of the elastic adjustment layer 101 is achieved to provide a fine feedback basis for subsequent elastic modulus adjustment. The pressure sensing layer 102 is provided with a piezoelectric sensor array and a multilayer graphene film embedded in the piezoelectric sensor array. The piezoelectric sensor array is used to generate an electric signal when the elastic adjustment layer 101 is pressed, and the graphene film serves as a conductive electrode layer and signal enhancement to improve overall sensing sensitivity and signal transmission efficiency, which is suitable for flexible fitting and large-area distributed pressure sensing requirements.

[0022] In some examples, the material of the elastic adjustment layer 101 includes one of a magneto-rheological elastomer, an electroactive polymer, a thermotropic polymer, and a gas bag composite film structure. The magneto-rheological elastomer can change the arrangement of its internal particles under the action of a magnetic field, thereby changing the regional stiffness and the elastic modulus of the elastic adjustment layer 101; the electroactive polymer can control its flexibility by adjusting the voltage, thereby changing the elastic modulus of the elastic adjustment layer 101; the thermotropic polymer has obvious differences in elastic modulus at different temperatures, and the gas bag composite film structure can change the local support force by adjusting the gas pressure. Based on the controllable materials described above, the elastic adjustment layer 101 combines with a local physical excitation source to achieve dynamic and fine control of the elastic modulus of different regions of the polishing pad, thereby adapting to the polishing requirements under different curvatures and stress states.

[0023] Specifically, when the material of the elastic adjustment layer 101 is a magneto-rheological elastomer, the control layer 103 adjusts the elastic modulus of at least one region of the elastic adjustment layer 101 through an electromagnetic coil array. Specifically, when the material of the elastic adjustment layer 101 is a magneto-rheological elastomer, the control layer 103 applies a local magnetic field to at least one region of the elastic adjustment layer 101 through an electromagnetic coil array arranged in the corresponding region of the elastic adjustment layer 101, thereby adjusting the elastic modulus of the region. The electromagnetic coil array is composed of multiple independently controlled electromagnetic coils, and each coil corresponds to an elastic adjustment region. By adjusting the current size or excitation frequency of the electromagnetic coil, independent control of the magnetic field strength of different regions can be achieved, thereby realizing the elastic modulus adjustment of different regions of the elastic adjustment layer 101, and making the surface pressure of the polishing pad tend to be uniformly distributed.

[0024] In some examples, in order to prevent the elastic adjustment layer 101 from being directly worn, contaminated or mechanically impacted and damaged during the grinding process, the grinding pad in the present application is also provided with a protective layer, which is arranged on the side of the elastic adjustment layer 101 away from the pressure sensing layer 102, for protecting the elastic adjustment layer 101 from direct wear or contamination during the grinding process, while maintaining stable contact between the grinding surface and the workpiece. The protective layer material can be selected from high-wear-resistant polyurethane film, flexible silica gel, polyimide film, PTFE film, etc., and the thickness is preferably between 0.1 mm and 1 mm, so as to provide effective protection without affecting the elastic transmission performance. Although the elastic modulus of the protective layer is fixed, due to its close arrangement on the elastic adjustment layer 101, the stress response and deformation behavior of the corresponding region of the protective layer will also change accordingly with the dynamic adjustment of the elastic modulus of each region of the elastic adjustment layer 101, so as to realize the variability of the "equivalent elastic modulus" of the overall grinding pad surface. Through this structural design, it can still ensure that the workpiece experiences uniformity adjustment effect of pressure distribution on the macro level.

[0025] Based on the same concept, the present application also provides an elastic modulus adjustment method of a grinding pad, as shown in Figure 2 The method comprises:

[0026] S201, collecting the pressure distribution information of the elastic adjustment layer during the grinding process of the elastic adjustment layer;

[0027] S202, determining the grinding pressure of each region of the elastic adjustment layer according to the pressure distribution information, and generating corresponding adjustment instructions according to the grinding pressure of each region of the elastic adjustment layer;

[0028] S203, adjusting the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions, so that the pressure of the elastic adjustment layer is uniformly distributed.

[0029] In some examples, the material of the elastic adjustment layer is magneto-rheological elastomer, and the adjustment of the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions so that the pressure of the elastic adjustment layer is uniformly distributed comprises: according to the adjustment instructions, controlling the electromagnetic coil array arranged in the corresponding region of the elastic adjustment layer to apply a local magnetic field to at least one region of the elastic adjustment layer, so as to adjust the elastic modulus of at least one region of the elastic adjustment layer, so that the pressure of the elastic adjustment layer is uniformly distributed.

[0030] In some examples, the material of the elastic adjustment layer is a magneto-rheological elastomer, and the elastic modulus of at least one region of the elastic adjustment layer is adjusted according to the adjustment instruction to make the pressure of the elastic adjustment layer uniformly distributed, including: according to the adjustment instruction, controlling the electromagnetic coil array arranged in the corresponding region of the elastic adjustment layer to apply a local magnetic field to at least one region of the elastic adjustment layer to adjust the elastic modulus of at least one region of the elastic adjustment layer, so that the pressure of the elastic adjustment layer is uniformly distributed.

[0031] In some examples, the pressure distribution information of the elastic adjustment layer is collected, including: collecting the pressure distribution information of the elastic adjustment layer through the pressure sensing layer, and the pressure sensing layer includes: a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array.

[0032] In some examples, after the elastic modulus of at least one region of the elastic adjustment layer is adjusted according to the adjustment instruction to make the pressure of the elastic adjustment layer uniformly distributed, the method further includes: collecting the pressure distribution information of the elastic adjustment layer through the pressure sensing layer, and the pressure sensing layer includes: a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array.

[0033] Specifically, after the grinding starts, the piezoelectric sensor array monitors the surface pressure distribution of the elastic adjustment layer in real time; then the pressure distribution is converted into an electrical signal (pressure distribution information) and transmitted to the AI control system (adjustment layer); the AI control system analyzes and processes the electrical signal, dynamically optimizes the removal function; according to the optimization result, an electric field is applied to the elastic adjustment layer to adjust the surface elastic modulus of the elastic adjustment layer; the grinding continues, and the above monitoring, analysis and adjustment process is repeatedly performed until the surface accuracy requirement is met.

[0034] Since the present application can monitor the pressure distribution of the elastic adjustment layer in real time and dynamically adjust the surface elastic modulus of the elastic adjustment layer, the grinding pressure is uniformly applied to the workpiece surface, and the local over-grinding or under-grinding phenomenon is avoided. Combined with the optimization of the removal function by the AI algorithm, the material removal amount can be more accurately controlled, and therefore the surface accuracy convergence speed is improved by 80% compared with the traditional grinding pad. The elastic modulus of the traditional grinding pad cannot be adjusted, and after wear, the grinding quality cannot be continuously guaranteed, and frequent replacement is required. However, the elastic modulus of the grinding pad of the present application can be dynamically adjusted according to the actual grinding condition, and the grinding performance is always good, so that the service life of the grinding pad is 10 times that of the traditional grinding pad. The extension of the service life of the grinding pad reduces the replacement frequency, and reduces the purchase cost and downtime maintenance cost of the grinding pad. At the same time, the improvement of the surface accuracy convergence speed shortens the grinding processing time and improves the production efficiency, further reducing the production cost. The AI algorithm can learn and adapt to different grinding conditions and workpiece requirements, so that the intelligent grinding pad of the present application can be widely used in precision grinding processing in various high-end manufacturing fields such as semiconductors and optical elements.

[0035] All the optional technical solutions described above can be combined to form optional embodiments of the present application, which will not be described one by one here.

[0036] The following is an embodiment of the elastic modulus adjusting device of the polishing pad of the present application, which can be used to perform the method embodiments of the present application. For details not disclosed in the elastic modulus adjusting device embodiment of the polishing pad of the present application, please refer to the method embodiments of the present application.

[0037] The present embodiment also provides an elastic modulus adjusting device for assembling a polishing pad, as shown in the figure, the elastic modulus adjusting device for assembling a polishing pad comprises: Figure 3

[0038] The collection module 301 is configured to collect the pressure distribution information of the elastic adjusting layer during the polishing process of the elastic adjusting layer.

[0039] The generation module 302 is configured to determine the polishing pressure of each region of the elastic adjusting layer according to the pressure distribution information, and generate corresponding adjustment instructions according to the polishing pressure of each region of the elastic adjusting layer.

[0040] The adjustment module 303 is configured to adjust the elastic modulus of at least one region of the elastic adjusting layer according to the adjustment instructions, so that the pressure of the elastic adjusting layer is uniformly distributed.

[0041] In some examples, the material of the elastic adjusting layer is magneto-rheological elastomer, and the adjustment module 303 is further configured to control the electromagnetic coil array arranged in the corresponding region of the elastic adjusting layer to apply a local magnetic field to at least one region of the elastic adjusting layer according to the adjustment instructions, so as to adjust the elastic modulus of at least one region of the elastic adjusting layer, and make the pressure of the elastic adjusting layer uniformly distributed.

[0042] In some examples, the collection module 301 is further configured to collect the pressure distribution information of the elastic adjusting layer through the pressure sensing layer, and the pressure sensing layer comprises: a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array.

[0043] In some examples, the adjustment module 303 is further configured to collect the pressure distribution information of the elastic adjusting layer through the pressure sensing layer, and the pressure sensing layer comprises: a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array

[0044] ​According to the technical scheme provided in the embodiments of the present application, the collecting module is configured to collect pressure distribution information of the elastic adjustment layer during the grinding process of the elastic adjustment layer; the generating module is configured to determine the grinding pressure of each region of the elastic adjustment layer according to the pressure distribution information, and generate corresponding adjustment instructions according to the grinding pressure of each region of the elastic adjustment layer; and the adjusting module is configured to adjust the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions, so that the pressure of the elastic adjustment layer is uniformly distributed on the grinding pad, which realizes dynamic adjustment of the elastic modulus of the elastic adjustment layer, makes the grinding pressure uniformly distributed on the surface of the workpiece during the grinding process, and further makes the grinding pad adapt to the curved surface profile of the complex workpiece and the grinding requirements of different regions, thereby improving the surface shape precision of the workpiece, and avoiding the problem of uneven distribution of the surface pressure of the grinding pad in the prior art during the grinding process.

[0045] The above embodiments are only used to illustrate the technical scheme of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical scheme recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical scheme deviate from the spirit and scope of the technical scheme of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A polishing pad, characterized by, The polishing pad comprises an elastic adjustment layer, a pressure sensing layer, and a control layer; The pressure sensing layer is configured to collect pressure distribution information of the elastic adjustment layer and transmit the pressure distribution information to the control layer; The control layer is configured to determine polishing pressure of each region of the elastic adjustment layer according to the pressure distribution information, generate corresponding adjustment instructions according to the polishing pressure of each region of the elastic adjustment layer, and adjust the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions to make the pressure of the elastic adjustment layer uniformly distributed.

2. The polishing pad of claim 1, wherein, The surface of the elastic adjustment layer is provided with a plurality of pressure sensing regions; the pressure sensing layer is provided with a plurality of pressure sensing units, and each pressure sensing region corresponds to a pressure sensing unit.

3. The polishing pad of claim 1, wherein, The pressure sensing layer comprises a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array.

4. The polishing pad of claim 1, wherein, The material of the elastic adjustment layer comprises one of magneto-rheological elastomers, electroactive polymers, thermotropic polymers, and airbag composite film structures.

5. The polishing pad of claim 4, wherein, When the material of the elastic adjustment layer is the magneto-rheological elastomer, the control layer adjusts the elastic modulus of at least one region of the elastic adjustment layer through an electromagnetic coil array.

6. The polishing pad of claim 1, wherein, The polishing pad further comprises a protective layer arranged on the side of the elastic adjustment layer away from the pressure sensing layer.

7. A method for adjusting the modulus of elasticity of a polishing pad, comprising: The method comprises: Collecting pressure distribution information of the elastic adjustment layer during polishing of the elastic adjustment layer; Determining polishing pressure of each region of the elastic adjustment layer according to the pressure distribution information, and generating corresponding adjustment instructions according to the polishing pressure of each region of the elastic adjustment layer; Adjusting the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions to make the pressure of the elastic adjustment layer uniformly distributed.

8. The method of claim 7, wherein, The material of the elastic adjustment layer is the magneto-rheological elastomer, and adjusting the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions to make the pressure of the elastic adjustment layer uniformly distributed comprises: According to the adjustment instructions, controlling an electromagnetic coil array arranged in the corresponding region of the elastic adjustment layer to apply a local magnetic field to at least one region of the elastic adjustment layer to adjust the elastic modulus of at least one region of the elastic adjustment layer to make the pressure of the elastic adjustment layer uniformly distributed.

9. The method of claim 7, wherein, Collecting pressure distribution information of the elastic adjustment layer comprises: Collecting pressure distribution information of the elastic adjustment layer through a pressure sensing layer, wherein the pressure sensing layer comprises a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array.

10. The method of claim 7, wherein, After adjusting the elastic modulus of at least one region of the elastic adjustment layer according to the adjustment instructions to make the pressure of the elastic adjustment layer uniformly distributed, the method further comprises: Collecting pressure distribution information of the elastic adjustment layer through a pressure sensing layer, wherein the pressure sensing layer comprises a piezoelectric sensor array and a multi-layer graphene film embedded in the piezoelectric sensor array.

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