A composite u-shaped trench cmp polishing pad for ild processes

Abstract

The utility model relates to a kind of composite U-shaped trench CMP polishing pad for ILD technology, including body, body includes polishing surface, multiple concentric circle trench and multiple circular arc trench, and polishing surface is divided into inner ring area and outer ring area;Concentric circle trench is distributed in the inner ring area of polishing surface, and multiple concentric circle trench is annular arrangement, with the center of body as the center, and it is equidistant distribution from inside to outside along radial direction, forms multiple concentric circle structure;Circular arc trench is distributed in the outer ring area of polishing surface, and the outer ring area of polishing surface is formed with multiple fan-like regions, and circular arc trench in each fan-like region is evenly distributed in radial pattern;Concentric circle trench and circular arc trench are all U-shaped groove, can effectively reduce the uneven flow rate of liquid in polishing process, improve the uniformity of polishing and final surface precision.

Description

Technical Field

[0001] This utility model relates to the field of chemical mechanical polishing technology, and more specifically, to a composite U-groove CMP polishing pad for ILD process. Background Technology

[0002] Since the advent of the deep submicron era in integrated circuits, chemical mechanical planarization (CMP) has become the only key technology capable of achieving global nanoscale planarization of wafers. In both front-end (FEOL) and back-end (BEOL) chip fabrication processes, the CMP process for inter-layer dielectrics (ILDs) is particularly critical. ILD layers, typically composed of materials such as silicon dioxide (SiO2), have the core function of forming a flat insulating layer on the wafer surface to facilitate the construction of multilayer interconnect structures. With the exponential increase in chip structural complexity, the global and local flatness of the ILD layer has become a prerequisite for the success of subsequent photolithography, etching, and metallization processes. Insufficient ILD layer planarization leads to the amplification of minute surface undulations after multilayer stacking, resulting in a series of fatal defects such as insufficient lithographic depth, pattern distortion, and short circuits or open circuits in metal interconnects, directly destroying chip yield and performance. Therefore, ILD-CMP is no longer a simple "polishing" process, but a fundamental manufacturing step that precisely controls the chip topology and ensures the realization of circuit functions.

[0003] The working principle of CMP polishing pads is based on the combined effects of chemistry and mechanics. During the polishing process, the chemical components in the polishing slurry react with the surface of the material being polished, generating a softened layer that is easy to polish. Simultaneously, relative motion occurs between the polishing pad and the wafer, and the abrasive particles in the polishing pad and slurry perform physical and mechanical polishing on the material surface, peeling away the softened layer layer by layer, thereby achieving a highly planarized effect. The main functions of CMP polishing pads are: to uniformly distribute the polishing slurry and provide fresh replenishment for slurry circulation; to remove residues generated during the polishing process; to transfer the mechanical load required for material removal; and to maintain the mechanical and chemical environment required for the polishing process.

[0004] CMP polishing pads are typically disc-shaped and made of various materials, the most common being rigid porous polyurethane foam. The surface of the polishing pad is designed with narrow, high aspect ratio grooves. Most polishing pads on the market currently have right-angled rectangular concentric circular grooves. The disadvantages of this right-angled rectangular concentric circular groove structure are twofold: First, when the polishing fluid and waste materials rotate centrifugally on the polishing pad, waste materials can accumulate at the corners of the grooves, affecting the flow of the polishing fluid within the pad and thus impacting the polishing effect. Second, during the polishing process, the polishing fluid distribution is uneven, mainly manifested as more fluid at the inside and less at the outside, resulting in a stepped appearance on the finished product, affecting the quality of the finished product. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a composite U-groove CMP polishing pad for ILD process, which addresses the above-mentioned defects of the prior art.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A composite U-groove CMP polishing pad for ILD (Integrated Water Deposition) processes is constructed, comprising a body, wherein the body includes a polishing surface, multiple concentric circular grooves, and multiple arc grooves. The polishing surface is divided into an inner ring area and an outer ring area. The concentric circular grooves are distributed in the inner ring area of ​​the polishing surface, and the multiple concentric circular grooves are arranged in a ring, with the center of the body as the center, and are equidistantly distributed from the inside to the outside along the radial direction to form multiple concentric circular structures. The arc grooves are distributed in the outer ring area of ​​the polishing surface, and the outer ring area of ​​the polishing surface forms multiple fan-shaped regions, in which the arc grooves are uniformly radially distributed. Both the concentric circular grooves and the arc grooves are U-shaped grooves.

[0008] Preferably, the multiple concentric circular grooves are inclined from the outside to the inside, and the degree of inclination gradually decreases from the center to the outside; the multiple arc grooves in each fan-shaped region are inclined from the inside to the outside, and the degree of inclination gradually increases from the inside to the outside.

[0009] Preferably, the inclination angle of the concentric circular groove located at the center of the body ranges from 110° to 120°, the inclination angle of the U-shaped groove of the concentric circular groove near the outer ring area of ​​the polished surface ranges from 85° to 95°, and the inclination angle difference between two adjacent concentric circular grooves is 3° to 7°; the inclination angle of the arc groove located inside the fan-shaped area ranges from 75° to 85°, the inclination angle of the arc groove located outside the fan-shaped area ranges from 60° to 70°, and the inclination angle difference between two adjacent arc grooves is 3° to 7°.

[0010] Preferably, the U-shaped groove of the concentric circular groove near the outer ring area of ​​the polished surface has an inclination angle of 90°.

[0011] Preferably, any type of fan-shaped region has a groove near the adjacent fan-shaped region, and multiple arc grooves in any type of fan-shaped region converge towards the groove.

[0012] Preferably, the junctions between the sidewalls of both the concentric circular grooves and the arc grooves and the polished surface are treated with a smooth transition.

[0013] The beneficial effects of this invention are as follows: By designing concentric circular grooves in the inner ring area of ​​the CMP polishing pad and arc grooves in the fan-shaped area in the outer ring area, both types of grooves are U-shaped structures, and the inclination angle of the grooves gradually changes from the inside to the outside, thus achieving efficient distribution and retention of the polishing fluid, effectively preventing the polishing fluid from being thrown out due to centrifugal force, and improving the utilization efficiency of the polishing fluid; in addition, the transition between the concentric circular grooves and the arc grooves is smoothly connected, combined with the end groove design of the fan-shaped area, which can further prevent waste accumulation and liquid blockage, improve the uniformity and stability of the polishing process, and significantly improve the polishing quality and work efficiency. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the utility model will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a structural diagram of a composite U-groove CMP polishing pad for ILD process according to a preferred embodiment of the present invention;

[0016] Figure 2 This is a cross-sectional view of the concentric grooves of the composite U-shaped groove CMP polishing pad for ILD process according to a preferred embodiment of the present invention.

[0017] Figure 3 This is a cross-sectional view of the concentric groove inclination angle of the composite U-shaped groove CMP polishing pad for ILD process according to a preferred embodiment of the present invention.

[0018] Figure 4 This is a cross-sectional view of the right half of the concentric circular groove and arc groove of the composite U-shaped groove CMP polishing pad for ILD process according to another preferred embodiment of the present invention.

[0019] Figure 5 This is a cross-sectional view of the right half of the concentric circular groove and the arc groove of the composite U-shaped groove CMP polishing pad for ILD process, which is another preferred embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] The preferred embodiment of this utility model includes a composite U-groove CMP polishing pad for ILD processes, such as... Figure 1 As shown, see reference Figure 2-5 The system includes a body 1, which includes a polished surface 2, multiple concentric circular grooves 3, and multiple arc grooves 4. The polished surface 2 is divided into an inner ring area 21 and an outer ring area 22. The concentric circular grooves 3 are distributed in the inner ring area 21 of the polished surface 2. The multiple concentric circular grooves 3 are arranged in a ring, with the center of the body 1 as the center, and are distributed equidistantly from the inside to the outside along the radial direction to form multiple concentric circular structures. The arc grooves 4 are distributed in the outer ring area 22 of the polished surface 2. The outer ring area 22 of the polished surface 2 forms multiple fan-shaped areas, and the arc grooves 4 in each fan-shaped area are evenly radially distributed. Both the concentric circular grooves 3 and the arc grooves 4 are U-shaped grooves.

[0022] The polishing slurry drips into the center of the polishing pad, preferentially flowing into the concentric circular grooves 3 in the inner ring area. The inclined design of the concentric circular grooves 3 allows the polishing slurry to gradually flow outwards under centrifugal force. The annular arrangement and equidistant distribution of the concentric circular grooves 3 ensure uniform coverage of the polishing slurry in the inner ring area, avoiding concentration or thinning of the liquid. As the polishing slurry flows outwards, it gradually enters the arc-shaped grooves 4 in the outer ring area. The U-shaped groove structure and the inward-inward-inward-inclined design of the arc-shaped grooves 4 increase the holding force of the polishing slurry in the outer ring area, preventing the liquid from being thrown out by the centrifugal force of high-speed rotation. The radial distribution of the arc-shaped grooves 4 further optimizes the dispersion of the liquid, ensuring uniform coverage of the polishing slurry throughout the entire outer ring area. Waste generated during polishing (such as surface material debris) enters the concentric circular grooves 3 and arc-shaped grooves 4 with the polishing slurry and flows smoothly with the help of the smooth surface at the bottom of the U-shaped grooves. The groove design at the end of the fan-shaped area serves to concentrate and guide the waste, allowing it to be discharged through the groove 5 and preventing accumulation. The inner and outer rings of the polishing pad work together, utilizing the concentric circular grooves 3 and arc-shaped grooves 4 to guide, retain, and discharge the polishing fluid, ensuring uniform distribution across the entire working surface and improving polishing uniformity. The smooth transition design at the interface of the polishing pad surface reduces friction, further lowering the risk of wear during polishing. As the polishing pad rotates, the supply, distribution, retention, and discharge of polishing fluid form a dynamic cycle, ensuring efficient and stable polishing. Therefore, it can be said that the partitioned design of the inner and outer rings and the distribution of grooves in this invention ensure uniform flow and coverage of the liquid. The tilt angle and groove design optimize liquid retention and waste discharge. The smooth structure and rounded transition design of the U-shaped groove reduce friction and buildup, extending the service life of the polishing pad.

[0023] like Figure 2 , Figure 4As shown, multiple concentric circular grooves 3 are inclined from the outside to the inside, and the degree of inclination gradually decreases from the center to the outside; multiple arc grooves 4 in each fan-shaped region are inclined from the inside to the outside, and the degree of inclination gradually increases from the inside to the outside.

[0024] The concentric circular grooves 3 are inclined from the outside in, with the inclination gradually decreasing from the center outwards. This allows the polishing slurry to move rapidly outwards under centrifugal force while providing appropriate holding force to prevent excessive liquid loss. This design ensures uniform distribution of the polishing slurry in the inner ring area, improving liquid utilization efficiency. The arc-shaped grooves 4 are inclined from the inside out, with the inclination gradually increasing from the inside outwards. This provides stronger holding force for the polishing slurry in the outer ring area, preventing it from being thrown out due to excessive centrifugal force during high-speed rotation, thus achieving effective control of the polishing slurry. The concentric circular grooves 3 in the inner ring evenly guide the liquid to the outer ring, while the arc-shaped grooves 4 in the outer ring evenly disperse the liquid through their inclined design, reducing the phenomenon of excessive or insufficient liquid in local areas and ensuring uniform wetting and action across the entire polishing surface. The design of the gradually changing inclination from the inside out enhances the adaptability of the grooves to liquid in different radius areas, enabling the polishing pad to perform excellently in high-speed rotation or complex polishing processes. The tilted design not only improves the utilization rate of polishing fluid and reduces liquid waste, but also reduces the wear caused by waste material retention on the grooves and polished surfaces, extending the service life of the polishing pad.

[0025] like Figure 3 , Figure 5 As shown, the inclination angle of the concentric circular groove 3 located at the center of the body 1 ranges from 110° to 120°, the inclination angle of the U-shaped groove of the concentric circular groove 3 near the outer ring area 22 of the polished surface 2 ranges from 85° to 95°, and the inclination angle difference between two adjacent concentric circular grooves 3 is 3° to 7°; the inclination angle of the arc groove 4 located inside the fan-shaped area ranges from 75° to 85°, the inclination angle of the arc groove 4 located outside the fan-shaped area ranges from 60° to 70°, and the inclination angle difference between two adjacent arc grooves 4 is 3° to 7°.

[0026] In this embodiment, the inclination angle of the concentric circular groove 3 located at the center of the body 1 is preferably 114°, the inclination angle of the U-shaped groove of the concentric circular groove 3 near the outer ring area 22 of the polished surface 2 is preferably 90°, and the inclination angle difference between two adjacent concentric circular grooves 3 is 4° or 6°; the inclination angle range of the arc groove 4 located inside the fan-shaped area is preferably 82°, the inclination angle of the arc groove 4 located outside the fan-shaped area is preferably 66°, and the inclination angle difference between two adjacent arc grooves 4 is 4° or 6°.

[0027] The inclination angle range of the concentric groove 3 is designed to gradually change from 110° to 120° to 85° to 95°, preferably 114° to 90°, so that the polishing fluid maintains a moderate speed when flowing under the action of centrifugal force, avoids the liquid from flowing away too quickly, ensures that the liquid can effectively cover the inner ring area and gradually guide it to the outer ring area, and improves the utilization efficiency of the polishing fluid.

[0028] The angle range design of the arc groove 4 (gradually changing from 75° to 85° to 60° to 70°, preferably 82° to 66°) provides greater holding force by gradually reducing the angle of the outer ring area, preventing the liquid on the outside from being thrown out due to excessive centrifugal force.

[0029] Meanwhile, the polishing slurry distribution in the outer ring area was optimized, ensuring uniform liquid coverage and further improving polishing uniformity. The inner ring area (concentric groove 3) has a larger inclination angle, facilitating rapid flow and uniform liquid coverage; the outer ring area (arc groove 4) has a smaller inclination angle, which helps maintain liquid coverage and prevents leakage. This synergistic effect of the inner and outer rings enhances overall polishing uniformity. The inclination angle difference further optimizes liquid distribution, reducing polishing marks or defects on the polished surface caused by uneven liquid distribution, thereby improving the precision and quality of the polished surface. The optimized inclination angle design ensures that waste material is smoothly discharged from the arc groove 4 under the flow of polishing slurry, reducing the possibility of waste material accumulation in the groove and further reducing the risk of surface scratches caused by groove blockage. The inclination angle range and optimal value settings cover common polishing needs and allow adjustment of the inclination angle range or inclination angle difference according to specific process requirements to adapt to different types of materials, polishing slurries, and process conditions, increasing the versatility of the design.

[0030] like Figure 1 As shown, each type of fan-shaped area has a groove near its adjacent fan-shaped area, and multiple arc-shaped grooves 4 within each type of fan-shaped area converge towards this groove. This design, with grooves near adjacent fan-shaped areas and multiple arc-shaped grooves 4 converging towards them, effectively guides the polishing fluid and waste materials to flow towards the groove, preventing waste material accumulation within the arc-shaped grooves 4 and improving waste material discharge efficiency. Simultaneously, this design prevents excessive dispersion or loss of the polishing fluid at the end of the grooves, enhancing the retention and reuse performance of the polishing fluid, thereby further improving the uniformity and efficiency of the polishing process and extending the service life of the polishing pad.

[0031] like Figure 2-5As shown, the junctions between the sidewalls of both the concentric circular groove 3 and the arc-shaped groove 4 and the polished surface 2 are smoothly transitioned. This smooth transition significantly reduces frictional resistance during polishing, lowers the risk of debris accumulation at the junctions, and effectively prevents debris buildup and scratches on the workpiece surface. Simultaneously, the smooth transition design also improves the fluidity of the polishing fluid, allowing it to distribute and flow more smoothly between the grooves and the polished surface, thereby improving polishing uniformity, efficiency, and surface quality.

[0032] In summary, by combining the concentric circular grooves 3 in the inner ring and the arc-shaped grooves 4 in the outer ring, the polishing fluid can achieve efficient and uniform distribution on the polishing surface 2. The concentric circular grooves 3 in the inner ring area 21 ensure rapid fluid flow, while the arc-shaped grooves 4 in the outer ring area 22 effectively retain the fluid through their inclined and radial design, avoiding fluid ejection caused by centrifugal force. The U-shaped groove bottom design of the concentric circular grooves 3 and the arc-shaped grooves 4 provides good fluidity. Combined with the groove design at the end of the fan-shaped area of ​​the arc-shaped grooves 4, it can reduce the accumulation of waste and accelerate its discharge, significantly improving polishing efficiency. The inclined design of the grooves (the concentric circular grooves 3 inclined from the outside to the inside and the arc-shaped grooves 4 inclined from the inside to the outside) can effectively reduce the uneven flow rate of the fluid during the polishing process, improving the uniformity of polishing and the final surface finish. The smooth transition at the junction of the groove sidewalls and the polishing surface reduces frictional damage during the polishing process, extends the service life of the polishing pad, and ensures that debris can be quickly discharged from the grooves.

[0033] It should be understood that this utility model is not limited to the above-described preferred embodiments. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made in their shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this utility model.

Claims

1. A composite U-groove CMP polishing pad for ILD process, comprising a body (1), characterized in that, The body (1) includes a polished surface (2), multiple concentric circular grooves (3) and multiple arc grooves (4), and the polished surface (2) is divided into an inner ring area (21) and an outer ring area (22). The concentric circular grooves (3) are distributed in the inner ring area (21) of the polished surface (2). Multiple concentric circular grooves (3) are arranged in a ring, with the center of the body (1) as the center, and are distributed equidistantly from the inside to the outside along the radial direction to form multiple concentric circular structures. The circular arc grooves (4) are distributed in the outer ring area (22) of the polished surface (2). The outer ring area (22) of the polished surface (2) forms multiple fan-shaped areas, and the circular arc grooves (4) in each fan-shaped area are evenly radially distributed. Both the concentric circular groove (3) and the arc groove (4) are U-shaped grooves.

2. The composite U-groove CMP polishing pad for ILD process according to claim 1, characterized in that, The multiple concentric circular grooves (3) are inclined from the outside to the inside, and the degree of inclination gradually decreases from the center to the outside; the multiple arc grooves (4) in each fan-shaped region are inclined from the inside to the outside, and the degree of inclination gradually increases from the inside to the outside.

3. The composite U-groove CMP polishing pad for ILD process according to claim 2, characterized in that, The inclination angle of the concentric circular groove (3) located at the center of the body (1) ranges from 110° to 120°. The inclination angle of the U-shaped groove of the concentric circular groove (3) near the outer ring area (22) of the polished surface (2) ranges from 85° to 95°. The inclination angle difference between two adjacent concentric circular grooves (3) is 3° to 7°. The inclination angle of the arc groove (4) located inside the fan-shaped area ranges from 75° to 85°. The inclination angle of the arc groove (4) located outside the fan-shaped area ranges from 60° to 70°. The inclination angle difference between two adjacent arc grooves (4) is 3° to 7°.

4. The composite U-groove CMP polishing pad for ILD process according to claim 3, characterized in that, The U-shaped groove of the concentric circular groove (3) near the outer ring area (22) of the polished surface (2) has an inclination angle of 90°.

5. The composite U-groove CMP polishing pad for ILD process according to claim 1, characterized in that, A groove (5) is provided near the adjacent fan-shaped area in any type of fan-shaped area, and multiple arc grooves (4) in any type of fan-shaped area converge towards the groove (5).

6. The composite U-groove CMP polishing pad for ILD process according to claim 1, characterized in that, The junctions between the sidewalls of the concentric circular groove (3) and the arc groove (4) and the polished surface (2) are all treated with smooth transition.

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