Polishing pad

Abstract

The utility model provides a polishing pad, the upper surface is provided with a groove structure, the groove structure comprises a central annular groove group, a plurality of circular ring groove groups and a long arc groove group, and the central annular groove group comprises a plurality of first annular grooves which are sleeved in sequence; each annular groove group comprises a plurality of second annular grooves which are concentrically arranged at equal intervals in a sleeving manner, and the intervals of the second annular grooves in the annular groove groups are gradually reduced from the center to the periphery; the long arc-shaped groove set comprises a plurality of long arc-shaped grooves extending in the radial direction in an arc-shaped mode, and the inner ends of the long arc-shaped grooves communicate with the first annular groove located in the peripheral edge of the center annular groove set. According to the polishing pad provided by the utility model, through the long arc-shaped groove and each circular ring groove group, the uniform distribution of polishing liquid is facilitated, the formation of concentration gradient is avoided, the uniformity of the material removal rate is improved, a smoother discharge channel is provided for chippings, the accumulation of the chippings in the groove structure is reduced, and the service life of the polishing pad is prolonged. Therefore, the risk of scratching the surface of the wafer is reduced, and the yield is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the chemical mechanical polishing technical field of wafer, specifically relates to a polishing pad. BACKGROUND

[0002] Chemical mechanical polishing process (CMP) is to utilize chemical action and mechanical action to realize effective removal of wafer surface, so as to obtain smooth and undamaged wafer surface. In the polishing process, the polishing head is embedded with wafer and is pressed on the polishing pad with certain pressure, and rotates together, at the same time, polishing liquid is sprayed on the polishing pad, the polishing liquid reacts with wafer surface to form the oxidation layer with low hardness, then the oxidation layer is removed through mechanical grinding, so as to realize global planarization.

[0003] In the CMP process, the polishing pad not only bears chemical polishing liquid and its reaction product, but also transmits processing load to ensure the stability of the polishing process, and the design of the groove is one of the important factors affecting the polishing efficiency and wafer surface quality.

[0004] In the prior art, the grooves of the polishing pad are mostly designed as divergent linear grooves, equidistant annular grooves or a combination of the two. However, the debris particles such as silicon chips or abrasive fragments generated during the polishing process are easy to accumulate in the above-mentioned grooves, which increases the risk of scratching the wafer surface. At the same time, the traditional groove design has the problem of uneven radial flow rate of the polishing liquid, which easily leads to the formation of concentration gradient of the polishing liquid in the edge and center area of the wafer, and the diffusion of the chemical active substance is limited, thereby affecting the uniformity of polishing and polishing efficiency. UTILITY MODEL CONTENTS

[0005] The utility model embodiment provides a kind of polishing pad, to solve the technical problem of wafer surface scratching due to debris accumulation in prior art and the technical problem of affecting polishing uniformity due to the concentration gradient formed by uneven flow rate of polishing liquid.

[0006] To achieve the above object, the technical scheme adopted by the utility model is as follows: a polishing pad is provided, and an upper surface is provided with a groove structure, the groove structure comprises:

[0007] a central ring groove group is located in the central area of the polishing pad and comprises a plurality of first annular grooves arranged in sequence;

[0008] a plurality of circular groove groups are arranged in sequence from the outer periphery of the central ring groove group to the outer periphery of the polishing pad, each circular groove group comprises a plurality of second annular grooves arranged in sequence at equal intervals, and the spacing of the second annular grooves in each circular groove group gradually decreases from the center to the outer periphery; and

[0009] The long-arc-shaped groove set comprises a plurality of long-arc-shaped grooves, the long-arc-shaped grooves are arranged along the circumferential direction of the polishing pad, each long-arc-shaped groove extends along the arc direction of the radial direction of the polishing pad, and is in communication with the second annular groove.

[0010] In a possible implementation, the middle part of the long-arc-shaped groove is arc-shaped protruded to the side opposite to the rotation direction of the polishing pad.

[0011] In some embodiments, the long-arc-shaped groove comprises a groove body connected with the first annular groove and a plurality of branch grooves in communication with the outer end of the groove body, and the branch grooves respectively extend to the outer edge of the polishing pad in the arc direction of the rotation direction of the polishing pad.

[0012] In some embodiments, from the inner end of the long-arc-shaped groove to the outer edge of the branch groove, the depth of the long-arc-shaped groove gradually increases, and the width of the long-arc-shaped groove gradually decreases.

[0013] In some embodiments, the width of the inner end of the long-arc-shaped groove is smaller than the width of the first annular groove located at the outer peripheral edge of the central ring groove set.

[0014] In a possible implementation, the tangent direction of the inner end of the long-arc-shaped groove forms an included angle a with the tangent direction of the first annular groove, and the included angle a is less than or equal to 15°.

[0015] In a possible implementation, from the outer periphery of the central ring groove set to the outer periphery of the polishing pad, the depth of the second annular groove in each circular groove set gradually increases.

[0016] In a possible implementation, the coverage radius of the central ring groove set is 5%-15% of the radius of the polishing pad.

[0017] In a possible implementation, the cross-sectional shape of the first annular groove, the second annular groove and the long-arc-shaped groove is rectangular or trapezoidal.

[0018] In a possible implementation, the depth of the first annular groove is greater than the boundary layer thickness of the polishing liquid.

[0019] The beneficial effects of the polishing pad provided by this utility model are as follows: Compared with the prior art, the polishing pad of this utility model uses a central annular groove group as the initial storage area for polishing slurry. Combined with radially extending long arc-shaped grooves, the polishing slurry is rapidly diffused to the surrounding area until it completely covers the wafer polishing area. Simultaneously, by gradually decreasing the spacing of the second annular grooves within adjacent annular groove groups from the center to the outer periphery, each annular groove group forms a gradient distribution from sparse to dense. This matches the flow characteristics and pressure distribution of the polishing slurry in different areas, contributing to the uniform distribution of the polishing slurry, avoiding the formation of concentration gradients, and improving the uniformity of material removal rate. Furthermore, the long arc-shaped grooves connect with each of the second annular grooves during their radial extension, providing a smoother discharge channel for debris, reducing debris accumulation within the groove structure, thereby reducing the risk of scratching the wafer surface and improving yield. Attached Figure Description

[0020] 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.

[0021] Figure 1 A top view of a polishing pad provided in an embodiment of this utility model;

[0022] Figure 2 A schematic diagram of the connection structure between the central annular groove group and one of the long arc-shaped grooves provided in an embodiment of this utility model;

[0023] Figure 3 A side cross-sectional view of a polishing pad on the radius of an embodiment of this utility model (the long arc-shaped groove is not shown).

[0024] Figure 4 (1) is a structural schematic diagram of one embodiment of the cross-sectional shape of the first annular groove, the second annular groove, or the long arc-shaped groove provided in this utility model embodiment;

[0025] Figure 4 (2) is a structural schematic diagram of another embodiment of the cross-sectional shape of the first annular groove, the second annular groove, or the long arc-shaped groove provided in this utility model embodiment;

[0026] Figure 4 (3) is a structural schematic diagram of another embodiment of the cross-sectional shape of the first annular groove, the second annular groove, or the long arc-shaped groove provided in the present utility model.

[0027] The following are the labeling elements in the figure:

[0028] 1. Central annular groove group; 11. First annular groove; 2. Circular annular groove group; 21. Second annular groove; 3. Long arc groove group; 31. Long arc groove; 311. Branch groove; a is the angle between the tangent direction of the inner end of the long arc groove and the tangent direction of the first annular groove; b is the angle between the hypotenuse of one side of the symmetrical trapezoidal section and the bottom surface of the groove; c is the angle between the hypotenuse of the other side of the asymmetrical trapezoidal section and the bottom surface of the groove; m is the width of the first annular groove; n is the width of the inner end of the long arc groove; h1 is the depth of the first annular groove; h2 and h3 are the depths of the second annular groove. Detailed Implementation

[0029] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0030] It should be noted that when an element is referred to as being "set on" another element, it can be directly on or indirectly on the other element. It should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0031] Please refer to the following: Figures 1 to 4The present invention provides a polishing pad. The polishing pad has a groove structure on its upper surface, comprising a central annular groove group 1, multiple circular annular groove groups 2, and a long arc-shaped groove group 3. The central annular groove group 1 is located in the central region of the polishing pad and includes multiple first annular grooves 11 arranged sequentially. The multiple circular annular groove groups 2 are arranged sequentially from the outer periphery of the central annular groove group 1 to the outer periphery of the polishing pad. Each circular annular groove group 2 includes several concentrically arranged second annular grooves 21 at equal intervals. From the center to the outer periphery, the spacing between the second annular grooves 21 in each circular annular groove group 2 gradually decreases. The long arc-shaped groove group 3 includes multiple long arc-shaped grooves 31, which are arranged at intervals along the circumference of the polishing pad. Each long arc-shaped groove 31 extends radially along the polishing pad and communicates with each of the second annular grooves 21. The inner end of the long arc-shaped groove 31 communicates with the first annular groove 11 located at the outer periphery of the central annular groove group 1.

[0032] This embodiment provides a polishing pad that, compared to existing technologies, uses a central annular groove group 1 as the initial storage area for the polishing slurry. Combined with radially extending long arc-shaped grooves 31, the polishing slurry rapidly diffuses outwards until it fully covers the wafer polishing area. Simultaneously, by gradually decreasing the spacing of the second annular grooves 21 within adjacent annular groove groups 2 from the center to the outer periphery, each annular groove group 2 forms a gradient distribution from sparse to dense. This matches the flow characteristics and pressure distribution of the polishing slurry in different areas, contributing to uniform distribution of the polishing slurry, avoiding the formation of concentration gradients, and improving the uniformity of material removal rate. Furthermore, the long arc-shaped grooves 31 connect with each of the second annular grooves 21 during their radial extension, providing a smoother discharge channel for debris, reducing debris accumulation within the groove structure, thereby reducing the risk of scratching the wafer surface and improving yield.

[0033] In this embodiment, the central annular groove group 1 provides reliable support for the wafer and can meet the storage requirements of a single polishing slurry spraying cycle (usually a continuous supply of polishing slurry within 1-3 seconds), which helps to extend the residence time of the polishing slurry on the polishing pad.

[0034] Multiple circumferentially spaced long arc-shaped grooves 31 divide the polishing pad into multiple "paddle-shaped" regions, forming high-speed diffusion channels for the polishing slurry. The included angle between two adjacent long arc-shaped grooves 31 is 8°-15°, which can reasonably optimize the distribution density of the long arc-shaped groove group 3. If the long arc-shaped grooves 31 are distributed too densely, it will cause interference in the flow of the polishing slurry; if the long arc-shaped grooves 31 are distributed too sparsely, it will reduce the coverage of the long arc-shaped groove group 3, thereby affecting the diffusion rate of the polishing slurry to the outer periphery of the polishing pad.

[0035] The inner end of the long arc-shaped groove 31 is connected to the first annular groove 11 on the outermost periphery of the central annular groove group 1, ensuring that the polishing fluid can smoothly enter the long arc-shaped groove 31 without damaging the support capacity of the central annular groove group 1, thus avoiding the problem of wafer center depression.

[0036] In some embodiments, the aforementioned elongated arc-shaped groove 31 can be adopted as follows: Figure 1 The structure shown. See also Figure 1 The middle part of the long arc-shaped groove 31 has an arc-shaped protrusion on one side opposite to the direction of rotation of the polishing pad.

[0037] In this embodiment, the rotation direction of the polishing pad is... Figure 1 In the counterclockwise direction indicated by the middle arrow, specifically, the long arc-shaped groove 31 extends clockwise from the connection point with the first annular groove 11, and at the same time extends to the outer periphery of the polishing pad to the middle of the radius direction of the polishing pad, and then continues to extend outward in the counterclockwise direction to the outer edge of the polishing pad, so that the middle of the long arc-shaped groove 31 forms an arc-shaped protrusion facing away from the rotation direction of the polishing pad.

[0038] Optionally, the long arc-shaped groove 31 extends in a logarithmic spiral manner, with its radius of curvature gradually increasing from the center to the edge to adapt to the linear velocity gradient driven by centrifugal force (edge ​​linear velocity > center linear velocity), so that the polishing slurry naturally diffuses as the rotation radius increases, thereby making the distribution of polishing slurry on the polishing pad more uniform. This avoids the problem of polishing slurry concentrating in certain areas due to differences in linear velocity, which is beneficial to improving the uniformity and efficiency of polishing.

[0039] In addition, the arc-shaped protrusion in the middle of the long arc-shaped groove 31 changes the contact area and contact mode between the long arc-shaped groove 31 and the wafer surface, which to a certain extent increases the effective grinding area of ​​the oxide layer on the wafer surface. At the same time, during the rotation of the polishing pad, the arc-shaped protrusion can apply grinding forces of different directions and magnitudes to the wafer surface, which helps to improve the efficiency of mechanical grinding.

[0040] A modified embodiment of the above-mentioned long arc-shaped groove 31 is described in [reference needed]. Figure 1 The long arc-shaped groove 31 includes a groove body connected to the first annular groove 11 and multiple branch grooves 311 connected to the outer end of the groove body. The multiple branch grooves 311 extend arc-shapedly to the outer edge of the polishing pad in the direction of rotation of the polishing pad.

[0041] In this embodiment, the main body of the groove extends arcuately from the outer edge of the first annular groove 11 to the edge near the polishing pad. The aforementioned arcuate protrusion is located in the middle of the main body of the groove. Each main body of the groove is connected to 2-4 branch grooves 311 at its outer end. The included angle between the tangents of two adjacent branch grooves 311 is 10°-60°. The curvature of the branch groove 311 on the forward side of the polishing pad rotation direction is greater than the curvature of the branch groove 311 on the backward side.

[0042] Multiple branch trenches 311 form a "Y"-shaped or "tree-like" branch structure near the outer edge of the polishing pad, effectively increasing the coverage area of ​​the trench structure. This increases the contact area between the polishing fluid and the trench structure during flow, enhancing the ability to carry silicon chips or abrasive fragments generated during polishing. Simultaneously, the arc-shaped extension direction of the branch trenches 311 is consistent with the rotation direction of the polishing pad. During rotation, debris is more easily discharged along the branch trenches 311 with the polishing fluid, reducing debris accumulation within the trench structure and lowering the risk of scratching the wafer surface.

[0043] For example, the branch groove 311 increases the total surface area of ​​the groove structure by about 40%, which effectively expands the heat dissipation area. During the polishing process, the flow of polishing fluid can improve the convective heat dissipation efficiency and avoid the problem of local frictional heat temperature rise exceeding the chemical stability threshold of polishing fluid, which may cause the decomposition of polishing fluid components (such as premature failure of oxidant).

[0044] On the other hand, the centrifugal force during the rotation of the polishing pad allows the polishing slurry to flow more smoothly along these branch grooves 311, distributing it evenly across different areas of the polishing pad. This further improves the concentration uniformity of the polishing slurry in the wafer edge and center regions, enhances the diffusion effect of chemically active substances, and helps improve the uniformity and efficiency of polishing. Simultaneously, the distribution of the branch grooves 311 compensates for the centrifugal effect at the wafer edge, dispersing the contact stress at the edge across multiple branch grooves 311, thus preventing excessive contact pressure at the edge region and avoiding over-polishing of the wafer edge.

[0045] In some embodiments, the depth of the long arc-shaped groove 31 gradually increases and the width of the long arc-shaped groove 31 gradually decreases from the inner end of the long arc-shaped groove 31 to the outer edge of the branch groove 311.

[0046] For example, along the length of the long arc-shaped groove 31, from the inner end to the outer edge, the width decreases by 0.1 mm and the depth increases by 0.08 mm for every 10 mm of arc length, meaning the depth-to-width ratio of the long arc-shaped groove 31 gradually increases. By limiting different depths and widths, the flow velocity of the polishing fluid within the long arc-shaped groove 31 is controlled within the range of 0.5-1.2 m / s, avoiding the occurrence of turbulence.

[0047] In addition, the variation in the depth-to-width ratio of the long arc-shaped groove 31 can adapt to the centrifugal effect. The larger the depth-to-width ratio, the greater its capacity to hold polishing fluid, thereby mitigating the fluid ejection effect when the polishing pad rotates at high speed and ensuring a continuous supply of polishing fluid.

[0048] Specifically, based on the variation in the depth-to-width ratio of the long arc-shaped groove 31, the long arc-shaped groove 31 can be divided into three functional zones along its length: a high-speed section (inner starting point - 40% arc length), a buffer section (40%-70% arc length), and a steady-flow section (70%-100% arc length). The high-speed section has a lower depth and a larger width, used to accelerate the diffusion of the polishing slurry; the buffer section has an increasing depth and a decreasing width, used to balance the flow rate and pressure of the polishing pad; and the steady-flow section has a higher depth and a narrower width, used to suppress the centrifugal ejection of the polishing slurry.

[0049] In some embodiments, see Figure 2 The width of the inner end of the long arc-shaped groove 31 is smaller than the width of the first annular groove 11 located on the outer periphery of the central annular groove group 1.

[0050] The width of the first annular groove 11 within the central annular groove group 1 is relatively wide to improve its initial capacity for storing polishing fluid. The widths of each first annular groove 11 can be equal or unequal. In this embodiment, the first annular grooves 11 are set to have equal widths, with the inner end of the long arc-shaped groove 31 connected to the outermost first annular groove 11. The width at the connection point gradually decreases from the width m of the first annular groove 11 to the width n of the inner end of the long arc-shaped groove 31, reducing abrupt changes in fluid flow at the connection point and ensuring smooth flow of the polishing fluid.

[0051] In some possible embodiments, see Figure 2 The tangent direction at the inner end of the long arc-shaped groove 31 forms an angle α with the tangent direction of the first annular groove 11, and the angle α ≤ 15°.

[0052] The limitation of the included angle α allows for a relatively smooth transition of the polishing slurry from the first annular groove 11 to the long arc groove 31. The polishing slurry will not generate large turbulence or eddies due to the abrupt change in direction during the flow process, thus ensuring the stability of the polishing slurry flow and helping to maintain the uniformity of the polishing slurry flow across the entire polishing pad surface.

[0053] Furthermore, because the polishing fluid flows smoothly and precisely, it is more effective at carrying and removing debris generated during the polishing process. The debris can flow more smoothly with the polishing fluid, reducing the accumulation of debris at the trench connection points caused by turbulent flow, which helps to reduce the risk of debris scratching the wafer surface.

[0054] In some possible embodiments, see Figure 3From the outer periphery of the central annular groove group 1 to the outer periphery of the polishing pad, the depth of the second annular groove 21 in each annular groove group 2 gradually increases.

[0055] In this embodiment, taking three annular groove groups 2 as an example, they are defined as the first annular groove group, the second annular groove group, and the third annular groove group, respectively, starting from the outer periphery of the central annular groove group 1. The depth of the first annular groove 11 in the central annular groove group 1 is h1. The depth of the second annular groove 21 in the first annular groove group is equal to the depth h1 of the first annular groove 11. The depth of the second annular groove 21 in the second annular groove group is h2. The depth of the second annular groove 21 in the third annular groove group is h3. Therefore, h1 < h2 < h3.

[0056] During the polishing process, due to centrifugal force, the polishing slurry moves towards the edge of the polishing pad. The depth of the second annular groove 21 gradually increases, which better adapts to this distribution characteristic of the polishing slurry. The deeper second annular groove 21 can hold more polishing slurry, ensuring a sufficient supply of polishing slurry even at the edge of the polishing pad. This improves the uniformity of the polishing slurry distribution across the entire polishing pad surface, reduces the formation of concentration gradients, and facilitates uniform polishing.

[0057] Meanwhile, the deeper second annular groove 21 has a greater chip carrying capacity, making it easier for chips to be carried to the edge of the polishing pad and discharged, thereby improving the chip removal capacity of the polishing pad, reducing chip residue in the polishing area, reducing the risk of chips scratching the wafer surface, and helping to improve the surface quality of the polished wafer.

[0058] Furthermore, the annular groove group 2 with different depths of second annular groove 21 can match the dynamic load at different stages of the polishing process: in the rough polishing stage, the polishing pressure is high, and the deeper second annular groove 21 in the third annular groove group dominates the discharge of debris; in the fine polishing stage, the polishing pressure is relatively low, and the shallower second annular groove 21 in the first and second annular groove groups is used to maintain the uniform distribution of chemicals in the polishing fluid.

[0059] In some possible embodiments, the coverage radius of the central annular groove group 1 is 5%-15% of the radius of the polishing pad.

[0060] By limiting the coverage radius of the central annular groove group 1, it is possible to ensure that the central area of ​​the polishing pad has an appropriate amount of polishing fluid storage and supply capacity, while maintaining a relatively high rigidity in the central part of the polishing pad, improving the support capacity for the wafer center, and avoiding the problem of wafer center depression during the polishing process.

[0061] On the other hand, by limiting the coverage radius of the central ring groove group 1, the coverage area of ​​the long arc-shaped groove group 3 can be relatively guaranteed, thereby better controlling the diffusion and flow of polishing slurry to the outer periphery of the polishing pad, reducing problems such as over-polishing or under-polishing of the edge area caused by uneven distribution or turbulent flow of polishing slurry, and helping to improve the polishing quality of the wafer edge.

[0062] In some possible embodiments, see Figure 4 The cross-sectional shapes of the first annular groove 11, the second annular groove 21, and the long arc groove 31 are all rectangular or trapezoidal.

[0063] Rectangular cross section as Figure 4 As shown in Figure (1), its grooves are relatively simple to process and can provide a large storage space for polishing fluid. The trapezoidal cross-section grooves have a shape that is wider at the top and narrower at the bottom, which is beneficial for the discharge of debris during the polishing process.

[0064] The trapezoidal cross section can be Figure 4 The symmetrical trapezoidal cross section shown in (2) can also be Figure 4 The asymmetric trapezoidal cross section shown in (3) is preferably 60°-80°. This ensures the flow performance of the polishing fluid and the structural strength of the polishing pad. In the asymmetric trapezoidal cross section, the inclination angle of one side is b, and the inclination angle of the other side is c. The inclination angle c satisfies 60°≤c≤80° and c<b.

[0065] It should be noted that V-shaped cross-sections should be avoided in all the grooves mentioned above. The sharp corners at the bottom of the V-shaped cross-section can easily lead to polishing fluid residue and affect the fluidity of the polishing fluid.

[0066] In some embodiments, the depth h1 of the first annular groove 11 is greater than the boundary layer thickness of the polishing slurry.

[0067] The boundary layer refers to a layer of polishing fluid near the surface of the polishing pad, and its flow state has a significant impact on the polishing effect. When h1 is greater than the boundary layer thickness, the first annular groove 11 can provide more flow space for the polishing fluid, reduce the influence of the boundary layer effect, reduce the flow resistance of the polishing fluid, avoid the stagnation of the polishing fluid, and help to deliver fresh polishing fluid to the polishing area in a timely manner. At the same time, it can quickly remove the heat and debris generated during the polishing process, thereby improving polishing efficiency and quality.

[0068] Preferably, the depth h1 of the first annular groove 11 is 1.5 times the thickness of the polishing slurry boundary layer.

[0069] Compared with traditional polishing pads with concentric circles or straight grooves, the polishing pad provided by this utility model can achieve the following process capabilities: the wafer surface flatness is optimized by more than 20% through dynamic stress distribution, and the material removal rate is increased by 20%-30%; the contact stress at the edge of the polishing pad is reduced by 15%-20% through optimized groove structure, the chip removal efficiency is increased by 30%-50%, and the scratches on the wafer surface are reduced by 30%; the contact area between the polishing pad and the outside world is increased, the heat dissipation efficiency can be improved by 10%, and the life of the polishing pad is extended by about 3 times.

[0070] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A polishing pad having a grooved structure on its upper surface, characterized in that, The trench structure includes: The central annular groove group is located in the central region of the polishing pad and includes a plurality of first annular grooves arranged in sequence. Multiple annular groove groups are sequentially fitted from the outer periphery of the central annular groove group to the outer periphery of the polishing pad. Each annular groove group includes several concentrically fitted second annular grooves at equal intervals. From the center to the outer periphery, the spacing of the second annular grooves within each annular groove group gradually decreases. The long arc-shaped groove group includes multiple long arc-shaped grooves, which are arranged at intervals along the circumference of the polishing pad. Each long arc-shaped groove extends radially arc-shaped along the polishing pad and communicates with each of the second annular grooves. The inner end of the long arc-shaped groove communicates with the first annular groove located at the outer peripheral edge of the central annular groove group.

2. The polishing pad as described in claim 1, characterized in that, The middle part of the long arc-shaped groove protrudes in an arc shape to the side opposite to the rotation direction of the polishing pad.

3. A polishing pad as described in claim 2, characterized in that, The long arc-shaped groove includes a groove body connected to the first annular groove and multiple branch grooves connected to the outer end of the groove body. The multiple branch grooves extend arc-shaped to the outer edge of the polishing pad in the direction of rotation of the polishing pad.

4. A polishing pad as described in claim 3, characterized in that, From the inner end of the long arc-shaped groove to the outer edge of the branch groove, the depth of the long arc-shaped groove gradually increases, and the width of the long arc-shaped groove gradually decreases.

5. A polishing pad as described in claim 4, characterized in that, The width of the inner end of the long arc-shaped groove is smaller than the width of the first annular groove located at the outer periphery of the central annular groove group.

6. A polishing pad as described in claim 1, characterized in that, The tangent direction at the inner end of the long arc-shaped groove forms an angle α with the tangent direction of the first annular groove, and the angle α ≤ 15°.

7. A polishing pad as described in claim 1, characterized in that, From the outer periphery of the central annular groove group to the outer periphery of the polishing pad, the depth of the second annular groove in each annular groove group gradually increases.

8. A polishing pad as described in claim 1, characterized in that, The coverage radius of the central annular groove group is 5%-15% of the radius of the polishing pad.

9. A polishing pad as described in claim 1, characterized in that, The cross-sectional shapes of the first annular groove, the second annular groove, and the long arc-shaped groove are all rectangular or trapezoidal.

10. A polishing pad as described in claim 1, characterized in that, The depth of the first annular groove is greater than the boundary layer thickness of the polishing slurry.

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