Grinding head with self-cooling function and CMP equipment

Abstract

The invention provides a grinding head with a self-cooling function and CMP equipment, and belongs to the field of chemical mechanical grinding, the grinding head comprises a grinding head body, a retaining ring and a flexible pad, the retaining ring is coaxially arranged on the lower end face of the grinding head body, a retaining space is defined by the inner side of the retaining ring, and a coaxial first cooling flow channel is formed in the retaining ring; the flexible pad is arranged in the holding space, the upper side face of the flexible pad is connected with the grinding head body, the lower side face of the flexible pad is used for adsorbing a wafer, the flexible pad comprises a supporting layer and a cooling layer which are arranged from top to bottom, and the supporting layer is arranged between the grinding head body and the cooling layer; the cooling layer comprises an upper interlayer, a lower interlayer and an interlayer, the upper interlayer is connected with the supporting layer, the lower interlayer is used for adsorbing a wafer to be processed, the interlayer is used for connecting the upper interlayer and the lower interlayer, and the second cooling flow channel is arranged in the interlayer. Compared with the prior art, the technical problem that an existing grinding head is prone to temperature rise and heat accumulation in the grinding process is solved.

Description

Technical Field

[0001] The present invention belongs to the field of chemical mechanical polishing, and more specifically, relates to a polishing head with a self-cooling function. The present invention also relates to a CMP device. Background Art

[0002] In the semiconductor wafer manufacturing process, chemical mechanical polishing (CMP) equipment, as the core processing equipment, undertakes the key task of global wafer flattening. Specifically, the core process of chemical mechanical polishing (CMP) enables the wafer surface to be flattened through the synergy of chemical and mechanical effects. First, a polishing liquid (slurry) containing nanoparticles and chemical reagents is sprayed from the equipment inlet to the surface of the rotating polishing pad. The polishing head presses the wafer stably on the polishing pad. The wafer and the polishing pad rotate at different speeds at the same time. The pressure and friction applied by the polishing head make the lower surface of the wafer fully contact with the polishing liquid.

[0003] The development of third-generation semiconductor materials and their application in modern CMP processes has led to new challenges. For example, third-generation semiconductor materials like SiC and GaN are known for their hardness and brittleness. This has led to increasingly prominent issues in the CMP process, such as high pressure during grinding, long grinding times, severe heat generation, rapid wear of retaining rings, and accelerated aging of flexible membranes. This has significantly increased the cost of repairing and replacing grinding heads, as well as the frequency of maintaining and replacing retaining rings and flexible membranes (i.e., flexible pads). This has also led to a gradual increase in time and cost, and the inability to address the technical issues with existing grinding heads, which often suffer from heat buildup during use. Improvements are urgently needed. Summary of the Invention

[0004] The object of the present invention is to provide a grinding head with a self-cooling function to solve the technical problem that the existing grinding head is prone to heating up and accumulating heat during the grinding process.

[0005] To achieve the above object, the present invention adopts the following technical solution: providing a grinding head with a self-cooling function, comprising:

[0006] Grinding head body;

[0007] A retaining ring is coaxially arranged on the lower end surface of the grinding head body, the inner side of the retaining ring encloses a retaining space, and a coaxial first cooling channel is provided in the retaining ring;

[0008] A flexible pad is arranged in the holding space, the upper side of the flexible pad is connected to the lower end face of the grinding head body, the lower side of the flexible pad is used to adsorb wafers, the flexible pad includes a support layer and a cooling layer arranged in sequence from top to bottom, the support layer is arranged between the grinding head body and the cooling layer; the cooling layer includes an upper partition layer, a lower partition layer and an interlayer, the upper partition layer is connected to the support layer, the lower partition layer is used to adsorb wafers to be processed, the interlayer is arranged between the upper partition layer and the lower partition layer, the interlayer is used to connect the upper partition layer and the lower partition layer, and a second cooling channel is arranged in the interlayer.

[0009] In a possible implementation, the support layer includes at least one heat-insulating cavity formed therein.

[0010] In one possible implementation, the retaining ring includes a ring-shaped inner retaining frame and an outer covering layer, the inner retaining frame is coaxial with the retaining ring, the first cooling channel is coaxially opened in the inner retaining frame, the outer covering layer is covered on the outer periphery of the inner retaining frame, and the outer covering layer is fixedly connected to the lower end surface of the grinding head body.

[0011] In a possible implementation, the first cooling channel includes an inner ring channel and an outer ring channel, the inner ring channel and the outer ring channel are both coaxial with the retaining ring, and the outer ring channel is coaxially arranged on the outer periphery of the inner ring channel.

[0012] In a possible implementation, there are multiple thermal insulation cavities, and each thermal insulation cavity is stacked in the support layer along the up and down direction.

[0013] In a possible implementation, a diaphragm and a partition are provided in the support layer, the diaphragm is a plurality of diaphragms arranged at intervals in the up and down directions, the partitions are respectively provided between the diaphragms, and the heat insulation cavity is formed by the diaphragm and the partitions.

[0014] In a possible implementation, the cross-sectional width of the inner ring flow channel is greater than the cross-sectional width of the outer ring flow channel.

[0015] In a possible implementation, the structural strength of the inner retainer is greater than the structural strength of the outer covering layer.

[0016] In a possible implementation, a communication channel is further provided in the inner retainer, the communication channel is provided between the inner ring flow channel and the outer ring flow channel, and the communication port is used to connect the inner ring flow channel and the outer ring flow channel.

[0017] Compared with the prior art, the self-cooling grinding head provided by the present invention has the following advantages:

[0018] First, the grinding head body provides main support. The retaining ring is not only used to constrain the flexible pad, but its coaxially arranged first cooling channel can provide preliminary cooling to the edge of the grinding area. The support layer in the flexible pad is located between the retaining ring and the cooling layer, providing structural support and thermal insulation, while the cooling layer adopts a unique sandwich structure (upper partition, lower partition, interlayer), in which the second cooling channel arranged in the interlayer is adjacent to the lower partition used to adsorb the wafer. The first cooling channel and the second cooling channel cooperate with each other. The first cooling channel acts on the periphery of the wafer and the retaining ring itself, while the second cooling channel acts directly on the working surface of the adsorbed wafer, achieving close-range, targeted active cooling of the wafer adsorption area and its edge area, significantly reducing the operating temperature of the friction interface between the wafer and the grinding pad (or grinding fluid), and thus solving technical problems such as excessive wafer temperature caused by frictional heat generation during chemical mechanical polishing, causing wafer warping and deformation, uneven material removal rate, surface thermal damage, and failure of polishing fluid performance.

[0019] Secondly, at least one thermal insulation cavity is formed inside the support layer. The air (or other low thermal conductivity medium) in these thermal insulation cavities cooperates with the solid material of the support layer to form an effective thermal resistance barrier. The existence of the thermal insulation cavity significantly reduces the overall thermal conductivity of the support layer, and achieves the technical effect of effectively blocking the heat from the lower cooling layer (especially the second cooling channel) and the grinding area from being transferred upward to the grinding head body, thereby achieving the purpose of improving the thermal insulation performance of the flexible pad itself, preventing the grinding head body from overheating, and at the same time concentrating the cooling effect more on the wafer interface, which is conducive to further solving the technical problems of grinding head temperature rise, material aging and reduced cooling efficiency caused by heat upload.

[0020] In addition, the retaining ring is subdivided into an inner retaining frame and an outer covering layer. The high-strength inner retaining frame with a coaxial first cooling channel is responsible for bearing, and the outer covering layer covering the outer periphery of the inner retaining frame provides a reliable fixed connection interface with the lower end face of the grinding head body. The inner retaining frame and the outer covering layer are closely matched. The inner retaining frame focuses on the structural strength and flow channel accuracy of the cooling function, while the outer covering layer focuses on vibration buffering and adapting to possible minor deformations. While meeting the requirements of efficient cooling function, it has the structural strength required for a firm connection with the grinding head body, optimizes the structural functional zoning of the retaining ring, and improves overall reliability and service life.

[0021] Not only that, the first cooling channel is further designed as a coaxial inner ring channel and outer ring channel, which can form a double-ring or multi-ring cooling circuit. The above structure allows the coolant to cover different radial positions on the inside of the retaining ring (the area close to the flexible pad and the edge of the wafer) more evenly and densely, achieving the technical effect of more refined and uniform temperature control of the wafer edge area and its adjacent retaining ring body, significantly improving the cooling effect of the wafer edge area.

[0022] In addition, the insulating cavities in the support layer are arranged in a plurality and stacked in the vertical direction. The multi-layer stacked insulating cavities form continuous or discontinuous multiple thermal barriers in the thickness direction of the support layer. These air layers (or low thermal conductivity layers) overlap and cooperate with each other, extending the path of heat conduction in the vertical direction and increasing thermal resistance, thereby more effectively preventing heat from being uploaded to the grinding interface, protecting the grinding head body and improving cooling efficiency. This is conducive to solving the technical problem that the thermal insulation effect of a single-layer insulating cavity is limited and it is difficult to meet the full insulation requirements in a thin design.

[0023] The support layer is equipped with multiple diaphragms spaced vertically and partitions between them. The diaphragms provide the primary horizontal support structure, while the partitions vertically divide the insulation chambers into multiple independent compartments. The diaphragms, partitions, and insulation chambers work together to form a grid-like honeycomb support structure. This not only provides excellent thermal insulation (via multiple independent air cavities), but also significantly enhances the planar rigidity and overall structural stability of the support layer. This achieves the technical effect of significantly improving the support layer's resistance to compression and deformation while maintaining high thermal insulation. This ensures that the flexible pad maintains its shape under grinding pressure, providing smooth support for the cooling layer and wafer.

[0024] A connecting channel is provided in the inner retainer, located between the inner and outer ring flow channels. The connecting channel connects the inner and outer ring flow channels, allowing coolant to flow between the inner and outer flow channels. The above design provides a flow channel connection method, in which coolant flows sequentially through the inner and outer ring flow channels (or vice versa), achieving the technical effect of continuously cooling the center and edge areas of the wafer in a single loop. This simplifies the external coolant piping connection (requiring only one inlet and one outlet) and optimizes heat exchange efficiency through flow channel sequence design. This helps solve the technical problem that dual flow channels require more complex external piping control, which increases system complexity and cost.

[0025] Another object of the present invention is to provide a CMP device comprising the above-mentioned polishing head with self-cooling function.

[0026] Compared with the prior art, the CMP equipment in the present invention has all the benefits of the above-mentioned polishing head with self-cooling function, which will not be repeated here. At the same time, as the core executive component of the CMP equipment, the polishing head has excellent self-cooling ability and cooperates with the polishing platform, liquid supply system, control system, etc. of the equipment to achieve the technical effect of precise, efficient and stable active control of the wafer / polishing interface temperature during the entire CMP process, significantly improving the global and local flatness of the wafer after polishing, reducing defects (such as thermal damage and scratches), and improving the stability of material removal rate and process repeatability, which is conducive to solving key technical problems such as the decrease in wafer processing yield, narrowing of process window, and shortening of equipment maintenance cycle caused by the polishing thermal effect of CMP equipment in advanced processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 inventive work. In the drawings:

[0028] Figure 1 A bottom view schematically shows a retaining ring and a flexible pad in a grinding head with a self-cooling function provided by the present invention;

[0029] Figure 2 for Figure 1 A partial cross-sectional view of the portion indicated by A in the middle;

[0030] Figure 3 for Figure 2 An enlarged view of the part shown at C in the middle;

[0031] Figure 4 Schematic bottom view of the retaining ring of the grinding head with self-cooling function of the present invention;

[0032] Figure 5 for Figure 4 A cross-sectional view of the portion shown at B in the middle;

[0033] Figure 6 Schematic diagram of the structure of the inner cage.

[0034] In the picture:

[0035] 1. Grinding head body;

[0036] 2. Retaining ring; 21. Inner retainer; 211. First cooling channel; 2111. Inner ring channel; 2112. Outer ring channel; 22. Outer coating;

[0037] 3. Flexible pad; 31. Support layer; 311. Insulation cavity; 312. Diaphragm; 313. Partition; 32. Cooling layer; 321. Upper partition; 322. Lower partition; 323. Interlayer; 3231. Second cooling channel. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner" and "back" appear to indicate orientation or positional relationships, they are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0040] Furthermore, in the description of the present invention, unless otherwise expressly defined, the terms "mounted," "connected," "connect," and "connector" should be interpreted broadly. For example, a connection can be a fixed connection, a removable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] Please also refer to Figures 1 to 6The self-cooling grinding head provided by the present invention is now described. The self-cooling grinding head comprises a grinding head body 1, a retaining ring 2 and a flexible pad 3, wherein the retaining ring 2 is coaxially arranged on the lower end surface of the grinding head body 1, and the inner side of the retaining ring 2 encloses a retaining space, and a coaxial first cooling channel 211 is provided in the retaining ring 2; the flexible pad 3 is arranged in the retaining space, and the upper side of the flexible pad 3 is connected to the lower end surface of the grinding head body 1, and the lower side of the flexible pad 3 is used to absorb the wafer, and the flexible pad 3 comprises a support arranged in sequence from top to bottom. The supporting layer 31 and the cooling layer 32, the supporting layer 31 is arranged between the grinding head body 1 and the cooling layer 32; the cooling layer 32 includes an upper partition layer 321, a lower partition layer 322 and an interlayer 323, the upper partition layer 321 is connected to the supporting layer 31, the lower partition layer 322 is used to adsorb the wafer to be processed, the interlayer 323 is arranged between the upper partition layer 321 and the lower partition layer 322, the interlayer 323 is used to connect the upper partition layer 321 and the lower partition layer 322, and the second cooling channel 3231 is arranged in the interlayer 323.

[0043] During the specific implementation of the above embodiment, the grinding head body 1 provides main body support, the retaining ring 2 is not only used to constrain the flexible pad 3, but its coaxially arranged first cooling channel 211 can also perform preliminary cooling on the edge of the grinding area; the support layer 31 in the flexible pad 3 is located between the retaining ring 2 and the cooling layer 32, providing structural support and heat insulation, and the cooling layer 32 adopts a unique sandwich structure (upper partition 321, lower partition 322, interlayer 323), wherein the second cooling channel 3231 arranged in the interlayer 323 is adjacent to the lower partition 322 for adsorbing the wafer. The first cooling channel 211 and the second cooling channel 3231 cooperate with each other. The first cooling channel 211 acts on the periphery of the wafer and the retaining ring 2 itself, while the second cooling channel 3231 acts directly on the working surface above the adsorbed wafer, realizing close-range, targeted active cooling of the wafer adsorption area and its edge area, significantly reducing the working temperature of the friction interface between the wafer and the polishing pad (or polishing fluid), and thus solving technical problems such as excessive wafer temperature caused by frictional heat generation during chemical mechanical polishing, causing wafer warping and deformation, uneven material removal rate, surface thermal damage, and failure of polishing fluid performance.

[0044] Based on the above embodiment, a preferred embodiment is proposed, wherein the support layer 31 includes at least one heat insulation cavity 311 (such as Figure 2As shown). The air (or other low thermal conductivity medium) in the thermal insulation cavity 311 cooperates with the solid material of the support layer 31 to form an effective thermal resistance barrier. The presence of the thermal insulation cavity 311 significantly reduces the overall thermal conductivity of the support layer 31, blocking the heat from the lower cooling layer 32 (especially the second cooling channel 3231) and the grinding area from transferring upward to the grinding head body 1, improving the thermal insulation performance of the flexible pad 3 itself, preventing the grinding head body 1 from overheating, and at the same time more concentrating the cooling effect on the wafer interface, which is conducive to further solving the technical problems of grinding head temperature rise, material aging, and reduced cooling efficiency caused by heat upload.

[0045] In addition to the above feasible embodiments, a preferred embodiment is proposed, wherein the retaining ring 2 includes a ring-shaped inner retainer 21 and an outer covering layer 22 (see Figure 2 and Figure 5 ), the inner retainer 21 is coaxial with the retaining ring 2, the first cooling channel 211 is coaxially opened in the inner retainer 21, the outer covering layer 22 covers the outer periphery of the inner retainer 21, and the outer covering layer 22 is fixedly connected to the lower end face of the grinding head body 1. Among them, the inner retainer 21 is responsible for carrying the flexible pad 3, and the outer covering layer 22 covering the outer periphery of the inner retainer 21 provides a reliable fixed connection interface with the lower end face of the grinding head body 1. The inner retainer 21 and the outer covering layer 22 are closely matched. The inner retainer 21 focuses on the structural strength and channel accuracy of the cooling function, while the outer covering layer 22 focuses on the connection seal and adaptability to possible minor deformations. While meeting the requirements of efficient cooling function, it has the structural strength required for a stable connection with the grinding head body 1, optimizes the structural and functional zoning of the retaining ring 2, and improves overall reliability and service life.

[0046] A preferred embodiment of the first cooling channel 211 is proposed, in which the first cooling channel 211 comprises an inner ring channel 2111 and an outer ring channel 2112. Both the inner ring channel 2111 and the outer ring channel 2112 are coaxial with the retaining ring 2, and the outer ring channel 2112 is coaxially arranged on the periphery of the inner ring channel 2111. This creates a dual-ring or multi-ring cooling circuit, allowing the coolant to more evenly and densely cover different radial positions on the inner side of the retaining ring 2 (the area near the flexible pad 3 and the wafer edge), achieving a more refined and uniform temperature control of the wafer edge area and the adjacent retaining ring 2 body, significantly improving the cooling effect of the wafer edge area.

[0047] Based on the above embodiments, preferably, considering that the heat dissipation path in the center area of ​​the wafer may be longer or the heat accumulation is more significant, for the specific structure of the inner ring flow channel 2111 and the outer ring flow channel 2112, the cross-sectional width of the inner ring flow channel 2111 is greater than the cross-sectional width of the outer ring flow channel 2112. The larger cross-sectional area of ​​the inner ring flow channel 2111 and the smaller cross-sectional area of ​​the outer ring flow channel 2112 cooperate with each other, and can deliver more cooling capacity to the corresponding lower position of the center area of ​​the wafer in a targeted manner, thereby performing differentiated cooling liquid distribution according to the potential distribution difference of the heat load, optimizing the temperature distribution uniformity of the entire area below the wafer, and helping to solve the technical problem that the cooling flow channel with uniform cross-section may not match the actual thermal gradient distribution of the wafer grinding area, resulting in insufficient cooling of the central area.

[0048] A preferred embodiment is proposed, in which there are multiple insulation cavities 311, each insulation cavity 311 is stacked in the upper and lower directions in the support layer 31, and the multi-layer stacked insulation cavities 311 form continuous or discontinuous multiple thermal barriers in the thickness direction of the support layer 31. The above-mentioned air layers (or low thermal conductivity layers) are superimposed and coordinated with each other, which extends the heat conduction path in the vertical direction and increases the thermal resistance. Within the limited thickness of the support layer 31, its thermal insulation performance is maximized, the heat from the grinding interface is prevented from being uploaded, the grinding head body 1 is protected and the cooling efficiency is improved, thereby improving the technical problem that the thermal insulation effect of the single-layer insulation cavity 311 is limited and it is difficult to meet the sufficient insulation requirements in a thin design.

[0049] A preferred embodiment is proposed, wherein diaphragms 312 and partitions 313 are provided within the support layer 31. The diaphragms 312 are arranged in a vertically spaced arrangement, and the partitions 313 are provided between each diaphragm 312. The heat-insulating cavity 311 is enclosed by the diaphragms 312 and the partitions 313. In the specific implementation of the above embodiment, the partitions 313 are located between the diaphragms 312, separating the space between the diaphragms 312 to form independent heat-insulating cavities 311. The diaphragms 312 provide the primary horizontal support structure, while the partitions 313 vertically divide the heat-insulating cavities 311 into multiple independent chambers. The diaphragm 312, partition 313 and insulation cavity 311 cooperate with each other. This grid or honeycomb structure not only provides excellent thermal insulation performance (through the formation of multiple independent air cavities), but also significantly enhances the rigidity of the support layer 31 in the planar direction and the overall structural stability. Under the premise of ensuring high thermal insulation, it improves the technical effect of the pressure resistance and deformation resistance of the support layer 31, ensures that the flexible pad 3 maintains a stable shape under grinding pressure, and provides flat support for the cooling layer 32 and the wafer, thereby solving the technical problems that the support layer 31 may have insufficient rigidity and easy deformation under pressure due to the multi-layer insulation cavity 311 structure, which affects the adsorption flatness and polishing uniformity of the wafer.

[0050] In addition to the above-mentioned feasible implementation methods, for the insulation cavity 311, a plurality of insulation cavities 311 evenly arranged along the membrane surface of the diaphragm 312 can be provided between adjacent diaphragms 312, and each insulation cavity 311 is separated by the partition 313 mentioned above. The upper and lower adjacent insulation cavities 311 are staggered to form a honeycomb multi-chamber structure in the support layer 31. While ensuring the overall structural strength and insulation capacity of the support layer 31, the consistency of the internal structural strength of the support layer 31 is enhanced to ensure that the downward pressure provided by the support layer 31 is smooth and consistent.

[0051] In addition to the above-mentioned feasible implementation methods, in order to make the structural strength of the retaining ring 2 more reasonable, in a feasible implementation method, the structural strength of the inner retaining frame 21 is greater than the structural strength of the outer covering layer 22. In this way, through the above-mentioned structure, the high-strength inner retaining frame 21 is mainly responsible for bearing the coolant pressure, maintaining the shape stability of the first cooling channel 211 (especially the inner ring and outer ring channels 2112), and ensuring the overall structural strength of the retaining ring 2. The relatively low-strength outer covering layer 22 focuses on providing good connectivity, connection flexibility with the grinding head body 1, and shock absorption / buffering effects. The differentiated design of the structural strengths of the two cooperates with each other, so that the retaining ring 2 can integrate cooling and positioning functions, and achieve the technical effect of optimal balance of the overall performance of the retaining ring 2 under complex working conditions (fluid pressure, mechanical pressure, vibration), and ensure the long-term reliable operation of the cooling channel, so as to solve the technical problem that a single material or homogeneous structure is difficult to simultaneously meet the multiple stringent requirements of high-strength pressure bearing, channel retention and vibration reduction.

[0052] On the basis of the double-circle flow channel set up above, a preferred embodiment is proposed, in which a connecting channel is also provided in the inner retaining frame 21, and the connecting channel is provided between the inner ring flow channel 2111 and the outer ring flow channel 2112, and the connecting port is used to connect the inner ring flow channel 2111 and the outer ring flow channel 2112. In a specific implementation, the connecting channel connects the inner ring flow channel 2111 and the outer ring flow channel 2112, allowing the coolant to flow between the inner and outer flow channels. In the series mode, the coolant flows through the inner and outer ring flow channels 2112, and continuously cools the center area and edge area of ​​the wafer in a single loop.

[0053] In summary, compared with the prior art, the grinding head with self-cooling function provided by the present invention realizes active, efficient and close-range cooling of the heat at the grinding interface through the above-mentioned structural design (grinding head body 1, retaining ring 2 and its built-in coaxial first cooling channel 211, flexible pad 3 and its supporting layer 31 and cooling layer 32), especially the cooling layer 32 adopts an upper partition 321, a lower partition 322 and a sandwich 323 structure with a built-in second cooling channel 3231, which: the first cooling channel 211 acts on the periphery of the wafer and the retaining ring 2 itself, and the second cooling channel 3231 acts directly below the lower partition 322 of the cooling layer 32 that adsorbs the wafer. The two work together to significantly reduce the operating temperature of the friction interface between the wafer and the grinding pad, and effectively solve the core problems such as wafer warping and deformation, uneven material removal rate, surface thermal damage and polishing liquid failure caused by frictional heat generation during chemical mechanical polishing (CMP). Furthermore, the single-layer or multi-layer (especially stacked up and down) thermal insulation cavity 311 provided within the support layer 31 cooperates with the solid material of the support layer 31 to form a highly efficient thermal barrier, preventing the heat from being transferred upward to the grinding head body 1, thereby improving cooling efficiency and protecting the equipment. The retaining ring 2 adopts a split design consisting of a high-strength inner retaining frame 21 (carrying precision coaxial cooling channels, such as the inner ring channel 2111 and the outer ring channel 2112) and a flexible outer covering layer 22 (providing reliable connection and vibration buffering). These two components work together to solve the problem that a single structure is difficult to achieve both high-strength pressure bearing and shock absorption. The design of the inner ring channel 2111 having a larger cross-sectional width than the outer ring channel 2112 enables differentiated coolant distribution and optimizes the temperature uniformity of the area below the wafer. The provision of a connecting channel between the inner ring channel 2111 and the outer ring channel 2112 provides a series cooling mode, simplifying the external piping. Finally, the integrated application of the above-mentioned structure (including the diaphragm 312 and partition 313 in the support layer 31 to enhance the structural rigidity, the inner retaining frame 21 being stronger than the outer coating layer 22 to ensure overall reliability, etc.) enables the grinding head to achieve precise and stable control of the grinding interface temperature in the CMP equipment, significantly improving the global and local flatness of the wafer.

[0054] Another object of the present invention is to provide a CMP device, comprising the above-mentioned polishing head with self-cooling function.

[0055] Compared with the prior art, the CMP equipment in the present invention has all the benefits of the above-mentioned polishing head with self-cooling function, which will not be repeated here. At the same time, as the core executive component of the CMP equipment, the polishing head has excellent self-cooling ability and cooperates with the polishing platform, liquid supply system, control system, etc. of the equipment to achieve the technical effect of precise, efficient and stable active control of the wafer / polishing interface temperature during the entire CMP process, significantly improving the global and local flatness of the wafer after polishing, reducing defects (such as thermal damage and scratches), and improving the stability of material removal rate and process repeatability, which is conducive to solving key technical problems such as the decrease in wafer processing yield, narrowing of process window, and shortening of equipment maintenance cycle caused by the polishing thermal effect of CMP equipment in advanced processes.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A grinding head with self-cooling function, characterized in that: include: Grinding head body; A retaining ring is coaxially arranged on the lower end surface of the grinding head body, the inner side of the retaining ring encloses a retaining space, and a coaxial first cooling channel is provided in the retaining ring; A flexible pad is arranged in the holding space, the upper side of the flexible pad is connected to the lower end face of the grinding head body, the lower side of the flexible pad is used to adsorb wafers, the flexible pad includes a support layer and a cooling layer arranged in sequence from top to bottom, the support layer is arranged between the grinding head body and the cooling layer; the cooling layer includes an upper partition layer, a lower partition layer and an interlayer, the upper partition layer is connected to the support layer, the lower partition layer is used to adsorb wafers to be processed, the interlayer is arranged between the upper partition layer and the lower partition layer, the interlayer is used to connect the upper partition layer and the lower partition layer, and a second cooling channel is arranged in the interlayer.

2. The grinding head with self-cooling function according to claim 1, characterized in that: The supporting layer includes at least one heat-insulating cavity formed therein.

3. The grinding head with self-cooling function according to claim 2, characterized in that: The retaining ring includes a ring-shaped inner retaining frame and an outer covering layer. The inner retaining frame is coaxial with the retaining ring. The first cooling channel is coaxially opened in the inner retaining frame. The outer covering layer covers the outer periphery of the inner retaining frame, and the outer covering layer is fixedly connected to the lower end surface of the grinding head body.

4. The self-cooling polishing head according to claim 3, wherein: The first cooling channel includes an inner ring channel and an outer ring channel. The inner ring channel and the outer ring channel are both coaxial with the retaining ring. The outer ring channel is coaxially arranged on the outer periphery of the inner ring channel.

5. The grinding head with self-cooling function according to claim 2, characterized in that: There are multiple heat-insulating cavities, and each of the heat-insulating cavities is stacked in the support layer along the up-down direction.

6. The grinding head with self-cooling function according to claim 5, characterized in that: The support layer is provided with a diaphragm and a partition. The diaphragm is a plurality of diaphragms spaced apart in the vertical direction. The partitions are respectively provided between the diaphragms. The heat insulation cavity is formed by the diaphragm and the partitions.

7. The grinding head with self-cooling function according to claim 4, characterized in that: The cross-sectional width of the inner ring flow channel is greater than the cross-sectional width of the outer ring flow channel.

8. The grinding head with self-cooling function according to claim 3, characterized in that: The structural strength of the inner retainer is greater than the structural strength of the outer covering layer.

9. The grinding head with self-cooling function according to claim 4, characterized in that: The inner retainer is further provided with a communication channel, which is provided between the inner ring flow channel and the outer ring flow channel. The communication port is used to connect the inner ring flow channel and the outer ring flow channel.

10. A CMP device, characterized in that: The invention comprises the grinding head with self-cooling function as claimed in any one of claims 1 to 9.

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