Improved structure of chemical mechanical polishing head.

Abstract

To provide an improved structure of a chemical mechanical polishing head that realizes a practical structure suitable for advanced CMP processes by achieving both strength and light weight. [Solution] The improved structure of the chemical mechanical polishing head mainly includes a gas distribution base with a gas flow channel, a balancing ring frame that forms an airtight cavity with the gas distribution base, and an elastic diaphragm attached around the balancing ring frame to elastically transmit pressure. The diaphragm fixing ring is located below the balancing ring frame, and has a number of concentric grooves on its surface, each with a suction cup-shaped groove at intervals, forming a circular bead chain-type suction structure that supports suction and positive pressure release functions and enables independent pressure adjustment for each zone. The balancing ring frame is a disk with a central axis and a triangular pyramidal reinforcing wall at its bottom. The polishing head carrier can be made of aluminum alloy or stainless steel.

Description

[Technical Field]

[0001] The present invention relates to the technical field of chemical mechanical polishing tools, and more particularly to an improved structure for a chemical mechanical polishing head. [Background technology]

[0002] The main function of conventional chemical mechanical polishing (CMP) equipment used in semiconductor processes is to planarize the wafer surface with high precision through a polishing process, facilitating the deposition and etching of subsequent circuit layers. Although existing CMP polishing head equipment has basic polishing functions, it still has the following major drawbacks:

[0003] In most existing CMP polishing head wafer chucking structures, the pores are arranged concentrically, concentrating the chucking force in specific areas, leading to unstable suction and wafer slippage, affecting polishing accuracy and safety. In particular, with the current trend toward gradually increasing wafer dimensions (e.g., 12 inches and larger) and when used in ultra-thin wafer backside polishing processes, existing chucking mechanisms often suffer from uneven suction force distribution. This uneven chucking can cause warping or localized lifting of the wafer's bonded surface, further resulting in center dishing, edge roll-off, and breakage during polishing. Furthermore, when the chucking force is concentrated in the center, the edge cannot receive sufficient stress, making the wafer more susceptible to slippage and dropout during high-speed rotation, which not only affects process stability but also increases yield risk.

[0004] Additionally, the central body of existing CMP polishing heads is originally made of aluminum alloy, which is lightweight and easy to mold and operate. However, stress tends to concentrate in the shaft center during high-speed rotation or pressure application, making it prone to cracks at the L-shaped corner below the shaft. Generally, the shaft center must withstand the combined forces of the motor and pneumatic system during pressure and rotation, making it prone to fatigue stress concentration and cracking. In the past, high-speed rotation or high-pressure processes have caused shaft damage or eccentricity, leading to uneven polishing and even the scrapping of the entire machine. Summary of the Invention [Means for solving the problem]

[0005] In view of this, the present invention is mainly aimed at providing an improved structure of a chemical mechanical polishing head, which mainly includes at least one gas distribution base, a balance ring frame, an elastic diaphragm, a fixing ring, and a diaphragm fixing ring; the gas distribution base is disposed above the center of the annular carrier and has at least one gas flow passage connected thereto for controlling gas pressure; The balance ring frame is fitted into the carrier to form an airtight cavity together with the gas distribution base, and a diaphragm sheet is provided around the side of the balance ring frame; The elastic diaphragm is provided on the diaphragm sheet and is used to transmit pressure by elastically expanding and contracting, the fixing ring is provided below the carrier and surrounds the outer periphery of the diaphragm fixing ring; and The diaphragm fixing ring is located below the balance ring frame and has a plurality of concentrically arranged grooves on its surface, which communicate with the gas pressure control unit. Each groove has circular suction cup grooves spaced apart, forming a circular bead chain arrangement. The suction cup grooves adsorb the wafer in suction mode and release the wafer in positive pressure mode, supporting independent pressure adjustment for each zone.

[0006] Preferably, the balance ring frame is a disk having a central axis, and the diaphragm sheet on its outer periphery is a multi-layer stepped disk extending outward, with the bottom of the disk inclined toward the bottom end of the central axis and integrally connected to form a triangular pyramidal reinforcing wall.

[0007] Preferably, the balancing frame is made of an aluminum alloy or stainless steel, and the carrier is made of an aluminum alloy or stainless steel, and has a plurality of hollow holes spaced apart on its annular surface to reduce weight and balance the weight with the reinforced balancing frame.

[0008] Preferably, the circular suction cup grooves on the concentrically arranged inner and outer grooves are provided with two short inclined grooves in a one-to-two arrangement, which are connected to each other internally and externally to form a triangular lattice distribution. [Effects of the Invention]

[0009] Compared with conventional techniques, the improved chemical mechanical polishing head structure of the present invention offers the following structural advantages: The diaphragm fixing ring includes a plurality of circular suction cup grooves that form a bead chain, and can be arranged in a radial triangular lattice pattern, realizing multi-point distributed vacuum suction and positive pressure release, realizing zone-by-zone pressure control for each zone, and improving wafer bonding uniformity and polishing stability. As a result, the entire structure has the advantages of stable suction, light weight, high strength, and precise pressure distribution, improving wafer bonding uniformity and polishing stability and being more suitable for new-generation semiconductor wafer planarization processes. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a composite cross-sectional view of a chemical mechanical polishing head according to the present invention; [Figure 2] 1 is a plan view of a first embodiment of a diaphragm fixing ring according to the present invention; FIG. [Figure 3] FIG. 10 is a plan view of a second embodiment of the diaphragm fixing ring of the present invention. [Figure 4] FIG. 10 is a perspective view of a second embodiment of the diaphragm fixing ring of the present invention. [Figure 5] 1 is a partial exploded view of a chemical mechanical polishing head according to the present invention; [Figure 6] 1 is a cross-sectional view of a balance ring frame according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0011] In order to facilitate understanding of the content and effects of the present invention, the present invention will be described in detail below by citing specific embodiments with reference to the drawings. As shown in FIGS. 1 to 4, the improved structure of the chemical mechanical polishing head according to the present invention mainly includes at least one gas distribution base 1, a balance ring frame 2, an elastic diaphragm 3, a fixing ring 4, and a diaphragm fixing ring 5, The gas distribution base 1 is provided above the center of the annular carrier 10 and has at least one gas flow passage 15 connected thereto for controlling gas pressure; The balance ring frame 2 is fitted into the carrier 10 to form an airtight cavity 20 together with the gas distribution base 1, and a diaphragm sheet 22 is provided around the side of the balance ring frame 2. The elastic diaphragm 3 is provided on the diaphragm sheet 22 and is used to transmit pressure by elastically expanding and contracting. The fixing ring 4 is provided below the carrier 10 and surrounds the outer periphery of the diaphragm fixing ring 5; The diaphragm fixing ring 5 is located below the balance ring frame 2 and has a plurality of concentrically arranged grooves 51 on its surface, which communicate with the gas pressure control unit. Each groove 51 has circular suction cup grooves 50 spaced apart, forming a circular bead chain arrangement. The suction cup grooves 50 adsorb the wafer in suction mode and release the wafer in positive pressure mode, thereby supporting independent pressure adjustment for each zone.

[0012] 2, the concentric grooves 51 on the surface of the diaphragm fixing ring 5 are preferably further divided into two, an inner groove and an outer groove, and the circular suction cup grooves 50 in the outer groove 51 and the inner groove 51 are alternately arranged at intervals. In this way, in use, the surface of the diaphragm fixing ring 5 is provided with multiple rows of equally spaced circular suction grooves 50, which are arranged in series like suction cups to form a bead chain-like distribution, increasing the suction area and improving stability, and providing uniform multi-point suction according to different regions of the wafer, simulating a planar suction force distribution, effectively improving the stability of wafer bonding and reducing the risk of breakage.

[0013] 3 and 4, the outer groove 51 and the circular suction cup grooves 50 on the inner groove 51 are further provided with two short inclined grooves 510 in a one-to-two arrangement, which are connected to each other to form a triangular lattice distribution, having both the functions of gas pressure guide and mechanical support, improving the uniformity of wafer edge and inner bonding, providing more stable support and good gas pressure distribution, and accurately supporting zone-by-zone pressure control to achieve the practical purpose of fast wafer suction and release.

[0014] Preferably, as shown in Figures 5 and 6, the balancing frame 2 is a disk 23 having a central axis 21, and the diaphragm sheet 22 on its outer periphery is a multi-layer stepped disk extending outward, with the bottom of the disk 23 inclined toward the bottom end of the central axis 21 and integrally connected to form a triangular pyramidal reinforcing wall 25.

[0015] Preferably, the balancing frame 2 is made of aluminum alloy or stainless steel, and the carrier 10 is made of aluminum alloy or stainless steel, and for weight reduction, a plurality of hollow holes 101 are provided at intervals on the surface thereof, and preferably, the carrier 10 is further provided with a circumferential groove 110, and the plurality of hollow holes 101 are arranged at intervals within the circumferential groove 110.

[0016] In this way, the balance ring frame 2 can be manufactured from stainless steel, resulting in a stronger and more stable structure. Although the weight increases due to local modifications, the carrier 10 has a circumferential groove 110 on which a plurality of hollow holes 101 are provided at intervals in an annular shape, thereby enabling the carrier 10 to balance the weight of the reinforced balance ring frame 2 and the balance ring frame 2. This prevents the system from losing balance and synchronization due to uneven weights of the individual parts after assembly, and effectively maintains the efficiency of the entire CMP and the stability of the process.

[0017] Compared with conventional techniques, the improved structure of the chemical mechanical polishing head according to the present invention offers the following structural advantages: The overall design and material application are optimized, improving the deficiencies of existing polishing equipment in terms of strength, weight, and adhesion stability, thereby improving overall process efficiency and extending the service life of the equipment. The diaphragm fixing ring 5 includes a plurality of circular suction cup grooves 50 forming a bead chain, which can be arranged in a radial triangular lattice pattern, realizing multi-point distributed vacuum suction and positive pressure release, realizing zone-by-zone pressure control, and improving wafer bonding uniformity and polishing stability. As a result, the entire structure has the advantages of stable adhesion, light weight, high strength, and precise pressure distribution, improving wafer bonding uniformity and polishing stability and making it more suitable for the new generation of semiconductor wafer planarization processes.

[0018] In summary, this invention is novel and practical, and fully meets the requirements for utility model registration, and therefore a utility model registration is filed. However, the above content is merely a preferred embodiment of the invention and does not limit the scope of the invention. Therefore, all equivalent changes and modifications made based on the claims and the content of the specification of the invention should be included in the scope of protection of the utility model registration of this invention. [Explanation of symbols]

[0019] 1 Gas split base 10. Career 101 Hollow hole 110 Groove 15 Gas flow path 2 Balancing Frame 20 Airtight Cavity 21 Center axis 22 Diaphragm sheet 23 Disc 25 Reinforced Wall 3 Elastic diaphragm 4 Retaining ring 5 Diaphragm fixing ring 50 grooves 51 Groove 510 Short inclined groove

Claims

1. An improved structure of a chemical mechanical polishing head mainly includes at least one gas distribution base, a balance ring frame, an elastic diaphragm, a fixing ring, and a diaphragm fixing ring, wherein the gas distribution base is disposed above the center of an annular carrier and has at least one gas flow path, the balance ring frame is fitted into the carrier to form an airtight cavity with the gas distribution base, and a diaphragm sheet is disposed around the side of the balance ring frame, and the elastic diaphragm is disposed on the diaphragm sheet and is used for elastically expanding and contracting to transmit pressure. the diaphragm fixing ring is located below the balance ring frame and has a plurality of concentrically arranged grooves on its surface, which communicate with a gas pressure control unit, each groove having circular suction cup grooves spaced apart to form a circular bead chain arrangement, the suction cup grooves adsorbing the wafer in suction mode and releasing the wafer in positive pressure mode, and supporting independent pressure adjustment for each zone.

2. 2. The improved structure of a chemical mechanical polishing head according to claim 1, wherein the balancing frame is a disk having a central axis, the diaphragm sheet on its outer periphery is a multi-layer stepped disk extending outward, the bottom of the disk is inclined toward the bottom end of the central axis and is integrally connected to form a triangular pyramidal reinforcing wall, the balancing frame is made of aluminum alloy or stainless steel, the carrier is made of aluminum alloy or stainless steel, and for weight reduction, a plurality of hollow holes are provided at intervals on its annular surface to balance the weight with the reinforced balancing frame, and the plurality of hollow holes are further provided at intervals in a circular groove on the carrier.

3. 2. The improved structure of a chemical mechanical polishing head as described in claim 1, wherein the concentric grooves on the surface of the diaphragm fixing ring are further divided into two, an inner groove and an outer groove, and the circular suction cup grooves on the outer groove and the inner groove are alternately arranged at intervals, and the circular suction cup grooves on the outer groove and the inner groove are provided with two short inclined grooves in a one-to-two arrangement, which are connected inside and outside to form a triangular lattice distribution.

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