A polishing head, a polishing unit, and a polishing apparatus

Abstract

The application provides a polishing head, a polishing unit and a polishing device. The polishing head comprises a base assembly, an air film assembly installed below the base assembly and a retaining ring assembly arranged around the air film assembly. The retaining ring assembly comprises a retaining ring and a clamping element arranged at each corner of the retaining ring. The clamping elements are configured to cooperate to clamp four corners of a square substrate during polishing. The application can effectively avoid damage to the square substrate during polishing.

Description

Technical Field

[0001] This invention belongs to the field of chemical mechanical polishing technology and is used for processing semiconductor chips. Specifically, it relates to a polishing head, a polishing unit, and a polishing device. Background Technology

[0002] Chemical mechanical polishing (CMP) is a crucial technology for achieving global planarization and is widely used in semiconductor chip and display panel manufacturing. With the rapid development of display technology, the requirements for surface flatness, roughness, and subsurface defect depth of square glass substrates (such as substrates for liquid crystal displays and OLED displays) are becoming increasingly stringent. The polishing head, as the core component that directly contacts the substrate and applies the polishing load, achieves nanoscale surface morphology control through precise control of the substrate's back pressure.

[0003] However, square substrates (especially square glass substrates) have extremely high requirements for surface quality. During the polishing process, traditional polishing heads lack effective positioning between the square substrate and the polishing head, making it impossible to avoid relative movement between the backplate (or air film) and the substrate. This results in defects such as scratches on the substrate surface. Furthermore, stress concentration at the edges and four sharp corners of the square substrate makes it more susceptible to damage during movement, thus affecting the overall polishing quality of the substrate. Summary of the Invention

[0004] In view of this, the present invention provides a polishing head, a polishing unit, and a polishing apparatus, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0005] A first aspect of the present invention provides a polishing head for polishing a square substrate, comprising: a base assembly, an air film assembly mounted below the base assembly, and a retaining ring assembly, the retaining ring assembly being disposed around the air film assembly; the retaining ring assembly including a retaining ring and clamping elements disposed at each corner of the retaining ring, the clamping elements being configured to cooperate in polishing to clamp the four corners of the square substrate.

[0006] Optionally, the clamping element includes right-angle retaining blocks, and the clamping element is configured such that, in response to the polishing pressure, the right-angle retaining blocks of each clamping element simultaneously move toward the center of the polishing head to clamp the four corners of the square substrate;

[0007] In addition, in response to the release of the polishing pressure, the right-angle holding blocks of each clamping element move in the opposite direction to release the four corners of the square substrate.

[0008] Optionally, the clamping element further includes:

[0009] A top pin is slidably disposed in the retaining ring along the vertical direction, with an elastic reset member at the top, a top pin wedge block in the middle, and a bottom protruding from the bottom surface of the retaining ring;

[0010] A push rod is slidably disposed in the retaining ring in the horizontal direction. One end of the push rod is provided with a push rod wedge block that cooperates with the top pin wedge block, so as to convert the vertical movement of the top pin wedge block into the horizontal movement of the push rod wedge block through the inclined surface cooperation. The other end of the push rod faces the right-angle retaining block, so as to push the right-angle retaining block towards the center of the polishing head when the push rod wedge block moves inward horizontally.

[0011] The elastic reset element is used to drive the top pin to return to its initial position.

[0012] Optionally, the clamping element further includes a reset structure for driving the push rod and the right-angle retaining block back to their initial positions.

[0013] Optionally, the top pin includes an upper rod that protrudes upward from the inclined surface of the top pin wedge block and a lower rod that protrudes downward from the horizontal bottom surface of the top pin wedge block, the elastic reset member being a spring sleeved on the upper rod, and at least a portion of the lower rod protruding from the bottom surface of the retaining ring;

[0014] The top pin also includes a top pin cover block, the bottom of which is provided with a receiving hole for accommodating the upper rod and the spring, and the top pin cover block is fixedly disposed with the retaining ring.

[0015] Optionally, one of the top pin wedge block and the push rod wedge block has a ball bearing mounting groove on its inclined surface, and the other has a ball bearing track on its inclined surface. Ball bearings are installed in the ball bearing mounting groove, and the balls roll in the ball bearing track when the top pin wedge block and the push rod wedge block move relative to each other.

[0016] Optionally, the horizontal cross-section of the right-angle retaining block is L-shaped, the push rod is arranged along the diagonal of the retaining ring, and the end of the push rod wedge block opposite to the outer corner of the L-shape is aligned with the outer corner of the L-shape. An avoidance structure is provided at the inner corner of the L-shape so that when the right-angle retaining block clamps the square substrate, the inner corner of the L-shape does not contact the corner of the substrate.

[0017] Optionally, the retaining ring is a square ring structure, and each corner of the retaining ring is provided with a structure for mounting the clamping element, so that when the polishing head is pressed on the polishing pad, the top pin moves vertically upward until it is fully accommodated in the retaining ring, and the push rod pushes the right-angle retaining block to clamp the four corners of the square substrate.

[0018] A second aspect of the present invention provides a polishing unit comprising a polishing head as described in the first aspect.

[0019] A third aspect of the present invention provides a polishing apparatus, including a polishing unit as described in the second aspect.

[0020] This invention offers the following technical advantages: By setting clamping elements at each corner, the invention automatically triggers the clamping action using the polishing pressure, causing four right-angle holding blocks to move simultaneously towards the center and clamp the four corners of the square substrate. This effectively prevents relative movement between the square substrate and the air film assembly during polishing, avoiding substrate damage. Furthermore, the clearance structure at the inner corners of the right-angle holding blocks prevents the clamping force from directly acting on the substrate corners, preventing corner chipping or damage. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 This is a schematic diagram of the structure of a polishing unit provided in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of a polishing head provided in an embodiment of the present invention.

[0024] Figure 3 for Figure 2 A top view of the polishing head.

[0025] Figure 4 for Figure 2 An exploded view of the polishing head.

[0026] Figure 5 This is a schematic diagram of the structure of a polishing head provided in another embodiment of the present invention.

[0027] Figure 6 for Figure 5 Enlarged diagram of point A in the middle.

[0028] Figure 7 for Figure 5 An exploded view of the top pin of the polishing head.

[0029] Figure 8 This is a schematic flowchart of a substrate polishing method provided in an embodiment of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art should fall within the protection scope of the present invention.

[0031] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0032] In addition, in the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0033] This invention provides a polishing head 10, a polishing unit 100 including the polishing head 10, and a polishing apparatus 1000 including the polishing unit 100, for chemical mechanical polishing of non-circular substrates. Non-circular substrates are typically square substrates, particularly square glass substrates, which have been recognized as an important component of advanced packaging processes. This invention is one of the solutions proposed to address the stringent surface quality requirements of square glass substrates in advanced packaging processes.

[0034] like Figure 1 As shown, the polishing unit 100 of the present invention includes a polishing head 10 for holding and rotating a substrate, a polishing disk 20 covered with a polishing pad 21, a trimmer 30 for trimming the polishing pad 21, and a liquid supply section 40 for supplying polishing liquid.

[0035] During chemical mechanical polishing (CMP), the polishing disc 20 rotates, the liquid supply unit 40 sprays polishing liquid onto the surface of the polishing pad 21, the polishing head 10 adsorbs the substrate and presses it onto the polishing pad 21 covering the surface of the polishing disc 20, and then the polishing head 10 rotates and reciprocates radially along the polishing disc 20. Under the chemical action of the polishing liquid, the relative movement between the polishing head 10 and the polishing disc 20 causes the substrate to rub against the polishing pad 21, gradually polishing away the substrate surface in contact with the polishing pad 21 to achieve surface smoothing. During polishing, a dresser 30 is used to trim and activate the surface morphology of the polishing pad 21. Using the dresser 30, impurity particles remaining on the surface of the polishing pad 21 can be removed, such as abrasive particles in the polishing liquid and waste material detached from the substrate surface, and the surface deformation of the polishing pad 21 caused by abrasion can be smoothed.

[0036] like Figure 2 As shown, the polishing head 10 of the present invention includes a base assembly 11, an air film assembly 12 mounted below the base assembly 11, and a retaining ring assembly 13. The retaining ring assembly 13 is disposed around the air film assembly 12, and the air film assembly 12 is located within the area defined by the retaining ring assembly 13. The base assembly 11 can be connected to a spindle (not shown) to provide overall rigid downforce and rotational drive. The air film assembly 12 is connected to an air source; during polishing, positive pressure is applied to apply specific back loads to different positions of the substrate, and during transport, negative pressure is applied to vacuum-adsorb the substrate. The retaining ring assembly 13 is used to fix the position of the substrate, and its lower surface is provided with channels for the polishing liquid to enter and exit.

[0037] The retaining ring assembly 13 includes a retaining ring 131 and clamping elements 132 disposed at each corner of the retaining ring 131. The retaining ring 131 has a square ring structure, and mounting structures (e.g., cavities) for mounting the clamping elements 132 are respectively provided at the four corners. The four clamping elements 132 are configured to work together during polishing to clamp the four corners of the square substrate. When not polished, the clamping elements 132 are separated from the substrate, thus not affecting the adsorption and release of the substrate by the air film assembly 12.

[0038] Optional, such as Figure 3 As shown, the clamping element 132 includes right-angle retaining blocks 1321, which are positioned corresponding to the four corners of the square substrate and can horizontally clamp the substrate relative to the retaining ring. The clamping element 132 is configured such that, in response to the polishing downforce, each right-angle retaining block 1321 simultaneously moves towards the center of the polishing head to clamp the four corners of the square substrate; and, in response to the release of the polishing downforce, each right-angle retaining block simultaneously moves in the opposite direction to release the four corners of the square substrate. The polishing downforce is the downforce applied by the spindle polishing head.

[0039] In one embodiment, the clamping element 132 further includes an actuator 1322 responsive to polishing pressure. The actuator 1322 is horizontally positioned and adjacent to the right-angle retaining blocks, and can be any linear actuator 1322, such as an electric actuator. When the pressure exceeds a threshold, it can be determined that the polishing head has pressed the substrate onto the polishing pad. The actuator 1322 applies a horizontal driving force to the right-angle retaining blocks 1321, pushing the right-angle retaining blocks 1321 towards the center of the polishing head to clamp the four corners of the square substrate. In response to the release of the polishing pressure, each right-angle retaining block simultaneously moves in the opposite direction to release the four corners of the square substrate. The reverse movement of the right-angle retaining blocks can be driven by a reverse driving force provided by the actuator 1322, or it can be accomplished by, for example, a reset structure as described in a later embodiment.

[0040] Optionally, the driver 1322 includes an element with a positive piezoelectric effect, which is capable of outputting an electrical signal in response to pressure, and the driver 1322 applies a horizontal driving force to the right-angle holding block 1321 according to the electrical signal.

[0041] Optionally, the driver 1322 includes a piezoelectric element that can output pressure or displacement in response to an electrical signal. The clamping element 132 includes a sensor that detects the pressure during polishing. When the detected pressure exceeds a threshold, the sensor outputs an electrical signal to the driver 1322. The piezoelectric element of the driver 1322 responds to the electrical signal by outputting pressure or displacement, pushing the right-angle retaining block 1321 to clamp the four corners of the square substrate.

[0042] Optionally, the right-angle retaining block 1321 is a block structure with an L-shaped horizontal cross-section to match the corner shape of the retaining ring 131 and the square substrate. The driving part of the driver 1322 is arranged along the diagonal of the retaining ring 131 to align with the outer corner of the L-shape, thereby pushing the right-angle retaining block 1321 toward the center of the polishing head 10 so that the two inner sides of the L-shape clamp one corner of the substrate in a manner that contacts the two sides of the substrate; and / or, pulling the right-angle retaining block 1321 toward a direction away from the center of the polishing head 10 so that the two inner sides of the L-shape release one corner of the substrate in a manner that moves away from the two sides of the substrate.

[0043] Preferably, the inner corner of the L-shape is provided with a clearance structure, such as a chamfer, rounded corner, or notch. When the right-angle retaining block 1321 clamps the square substrate, the clearance structure 13213 makes the inner corner of the L-shape form a clamping structure with edge contact but corner clearance with the substrate, thereby not only stably clamping the substrate, but also avoiding collision with the corner of the substrate during clamping and the clamping force acting directly on the corner of the substrate, which would cause corner chipping or damage.

[0044] Optional, such as Figure 4 As shown (and referenced) Figure 5The base assembly 11 includes an upper base 111, a lower base 112, a flexible diaphragm 113, an upper pressure ring 114 and a lower pressure ring 115, an upper support 116 and a lower support 117. The upper base 111 and the lower base 112 are square, and the flexible diaphragm 113, the upper pressure ring 114 and the lower pressure ring 115, as well as the upper support 116 and the lower support 117 are all square rings.

[0045] The bottom edge region of the upper base 111 extends downward to form an extension 1111, and the extension is recessed upward at certain intervals to form a first mounting groove 1112. The top of the lower base 112 is recessed downward at certain intervals from the edge to form a second mounting groove 1121. The width of the top opening of the second mounting groove 1121 is the same as the width of the first mounting groove 1112, and the width of the bottom is smaller than the width of the opening. The lower base 112 is fitted inside the extension 1111, and the first mounting groove 1112 and the second mounting groove 1121 are aligned. The retaining ring 131 is fixed to the bottom of the extension 1111 and the lower base 112.

[0046] The upper bracket 116 is fixed in the first mounting groove 1112. The upper pressure ring 114 and the upper bracket 116 press and seal the edge of the flexible diaphragm 113 to seal the flexible diaphragm 113 and form a pneumatic chamber 118, and fix its upper part in the first mounting groove. The lower pressure ring 115 and the lower bracket 117 are used to press the flexible diaphragm 113 from the inside and outside of the flexible diaphragm 113 respectively to form the bottom of the pneumatic chamber 118, so that the pneumatic chamber 118 is floatingly disposed in the first mounting groove 1112 and the second mounting groove 1121. The pneumatic chamber 118 is connected to an air source through air passages provided in the upper base 111, the upper pressure ring 114 and the upper bracket 116. The air source is used to apply positive or negative pressure to the pneumatic chamber 118. When positive pressure is applied, the lower pressure ring 115 and the lower bracket 117 move downward; when negative pressure is applied, the lower pressure ring 115 and the lower bracket 117 move upward.

[0047] The second mounting groove 1121 is a square ring shape, with its corner area vertically penetrating the lower base 112 and forming a bottom opening at the bottom of the lower base 112. The right-angle retaining block 1321 is disposed in the second mounting groove 1121 in a manner connected to the bottom of the lower bracket 117, and can slide up and down relative to the bottom opening of the second mounting groove 1121.

[0048] Therefore, when positive pressure is introduced into the air pressure chamber, the right-angle retaining block 1321 moves downward under the push of the lower support 117 until it is stably pressed onto the polishing pad; at the same time, the driver 1322 pushes the right-angle retaining block 1321 outward to clamp the substrate. In other words, the downward pressure applied by the lower support 117 and the horizontal thrust applied by the driver 1322 work together to ensure that the right-angle retaining block 1321 will not wobble in the horizontal or vertical directions due to the relative movement of the polishing head or the unevenness of the polishing pad. That is, the substrate is stably clamped during the swinging and rotating motion of the polishing head, so that the edge of the square substrate will not collide with the inner wall of the retaining ring 131, and the edges and sharp corners of the stress concentration will not be damaged, resulting in a decrease in polishing quality.

[0049] However, the driver solution requires the placement of electrical signal components in the retaining ring. These components are not only susceptible to corrosion from the strong acid or alkali environment during the polishing process, but may also be affected by the electrochemical effects of metal ions, organic matter, etc. in the polishing waste, which in turn affects the clamping and fixation of the substrate.

[0050] Another embodiment of the present invention provides a purely mechanical square substrate clamping solution. For example... Figures 5-7 As shown, the clamping element 132 includes a right-angle retaining block 1321, a top pin 1323, and a push rod 1324. The top pin 1323 is slidably disposed in the retaining ring 131 in the vertical direction, and the push rod 1324 is slidably disposed in the retaining ring 131 in the horizontal direction. In the initial state (i.e., the unpolished state), the bottom of the top pin 1323 protrudes from the bottom surface of the retaining ring 131, and a top pin wedge block 3231 is disposed in the middle. One end of the push rod 1324 is provided with a push rod wedge block 3241 that cooperates with the top pin wedge block 3231, and the other end faces the right-angle retaining block 1321. The top pin 1323 slides upward in response to the polishing pressure. The push rod wedge block 3241, due to the inclined surface cooperation with the top pin wedge block 3231 during the upward sliding process, drives the push rod 1324 to slide horizontally inward, and further pushes the right-angle retaining block 1321 to move towards the center of the polishing head to clamp one corner of the substrate. Understandably, the four right-angled blocks work together to clamp the four corners of the substrate.

[0051] Optionally, the top of the top pin 1323 is provided with a resilient reset member, and the clamping element 132 also includes a reset structure. The resilient reset member is compressed when the top pin 1323 slides upward, thereby applying a downward force to the top pin 1323 to drive the top pin 1323 downward to its initial position after the polishing pressure is removed. The reset structure is used to drive the push rod 1324 and / or the right-angle retaining block 1321 to return to their initial positions.

[0052] Optionally, the top pin 1323 further includes an upper rod 3232 and a lower rod 3233, the upper rod 3232 protruding upward from the inclined surface of the top pin wedge block 3231, and the lower rod 3233 protruding downward from the horizontal bottom surface of the top pin wedge block 3231. When the top pin 1323 slides to its lowest position, at least a portion of the lower rod 3233 protrudes from the bottom surface of the retaining ring 131 to contact and be lifted by the polishing pad 21 when the polishing head 10 is pressed down.

[0053] A top pin cover 3234 is provided above the top pin 1323. The elastic reset element is preferably a spring 3235 sleeved on the upper rod 3232. The bottom of the top pin cover 3234 has a receiving hole for accommodating the upper rod 3232 and the spring 3235. The top pin cover 3234 is fixedly disposed with the retaining ring 131, used to limit and guide the upper rod 3232 and the spring 3235. When the top pin 1323 slides upward, the upper rod 3232 slides upward in the receiving hole, while the spring 3235 is compressed. And when the polishing head is lifted, the spring 3235 drives the top pin 1323 to slide downward to its initial position during its recovery process. The push rod wedge block 3241 is provided with an elongated through hole through which the upper rod 3232 passes. The push rod wedge block 3241 achieves horizontal displacement relative to the upper rod 3232 through the length direction of this elongated through hole.

[0054] Optionally, a ball bearing mounting groove 53 is provided on the inclined surface of one of the top pin wedge block 3231 and the push rod wedge block 3241, and a ball bearing track 54 is provided on the inclined surface of the other. Ball bearings 52 are installed in the ball bearing mounting groove 53. When the top pin wedge block 3231 and the push rod wedge block 3241 move relative to each other, the ball bearings 52 roll in the ball bearing track 54, achieving low-friction relative sliding.

[0055] Optionally, the right-angle retaining block 1321 is a block structure with an L-shaped horizontal cross-section to match the corner shape of the retaining ring 131 and the square substrate. The push rod 1324 is arranged along the diagonal of the retaining ring 131, and the inner end of the push rod 1324, that is, the end opposite to the push rod wedge block, is aligned with the outer corner of the L-shape. Thus, when the push rod 1324 slides horizontally inward, it pushes the right-angle retaining block 1321 toward the center of the polishing head 10, so that the two inner sides of the L-shape clamp one corner of the substrate in such a way that they contact the two sides of the substrate.

[0056] Preferably, the inner corner of the L-shape is provided with a clearance structure 13213, such as a chamfer, rounded corner, or notch. When the right-angle retaining block 1321 clamps the square substrate, the clearance structure 13213 makes the inner corner of the L-shape form a clamping structure with edge contact but corner clearance with the substrate, thereby not only stably clamping the substrate, but also avoiding collision with the corner of the substrate during clamping and the clamping force acting directly on the corner of the substrate, which would cause corner chipping or damage.

[0057] Optionally, the right-angle retaining block 1321 includes an upper right-angle retaining block portion 3211 and a lower right-angle retaining block portion 3212. The lower right-angle retaining block portion 3212 is movably connected to the upper right-angle retaining block portion 3211 (e.g., via a tenon-and-mortise structure or a groove structure). The upper right-angle retaining block portion 3211 is fixedly connected to the base assembly 11, and the lower right-angle retaining block portion 3212 is located in the corner space of the retaining ring 131 and moves inward when pushed by the push rod 1324. In other words, the retaining ring 131 only provides the moving space for the right-angle retaining block 1321 to clamp the substrate but does not provide a support or sliding structure, which not only provides a more stable clamping capability but also facilitates the processing and installation of various components.

[0058] Optionally, the reset structure includes a spring (not shown) disposed between the lower portion 3212 of the right-angle retaining block and the retaining ring 131, for returning the right-angle retaining block 1321 and the push rod 1324 to their initial positions.

[0059] Optional, such as Figure 5 As shown (and referenced) Figure 4 The base assembly 11 includes an upper base 111, a lower base 112, a flexible diaphragm 113, an upper pressure ring 114 and a lower pressure ring 115, as well as an upper support 116 and a lower support 117. The structure and connection relationships of each component are the same as in the aforementioned embodiments. The difference lies in... Figure 6 As shown, the upper part 3211 of the right-angle retaining block is disposed in the second mounting groove 1121 in a manner connected to the bottom of the lower bracket 117, and can slide up and down relative to the bottom opening of the second mounting groove 1121.

[0060] Therefore, when positive pressure is introduced into the air chamber, the right-angle retaining block 1321 moves downward under the push of the lower support 117 until it is stably pressed onto the polishing pad; at the same time, the push rod 1324 pushes the lower part 3212 of the right-angle retaining block outward to clamp the substrate. In other words, the positive pressure applied by the air chamber 118 and the pushing force applied by the push rod 1324 work together to ensure that the lower part 3212 of the right-angle retaining block will not wobble in the horizontal and vertical directions due to the relative movement of the polishing head or the unevenness of the polishing pad, thereby stably clamping the substrate throughout the polishing process, avoiding damage to the edges of the substrate, and ensuring the quality of polishing.

[0061] Optionally, the reset structure includes mating inclined surfaces 1325 respectively disposed on the lower base 112 and the lower part 3212 of the right-angle retaining block. The mating inclined surfaces 1325 are used to cooperate with the movement of the lower part 3212 of the right-angle retaining block, so that the lower part 3212 of the right-angle retaining block returns to the initial position after polishing.

[0062] Specifically, before polishing begins, the lower base 112 and the mating inclined surfaces 1325 on the lower portion 3212 of the right-angle retaining block are in contact with each other. In response to the polishing pressure, the lower support 117 pushes the right-angle retaining block 1321 downwards, and the push rod 1324 pushes the lower portion 3212 of the right-angle retaining block towards the center of the polishing head 10. During this process, the upper portion 3211 of the right-angle retaining block only moves downwards, while the lower portion 3212 of the right-angle retaining block moves downwards and inwards in a combined motion until the lower portion 3212 of the right-angle retaining block moves downwards to be flush with the bottom of the retaining ring 131 and clamps the substrate inwards. At this point, the lower base 112 and the mating inclined surfaces 1325 on the lower portion 3212 of the right-angle retaining block are in contact with each other.

[0063] When the polishing head 10 is lifted, the top pin 1323 is reset by the action of the spring 3235, so that the push rod 1324 no longer applies a pushing force to the lower part 3212 of the right-angle retaining block. Negative pressure is introduced into the air pressure chamber, and the lower bracket 117 pulls the right-angle retaining block 1321 upward. Under the action of the mating inclined surface, the lower part 3212 of the right-angle retaining block moves upward and also moves away from the initial position away from the center of the polishing head 10, and finally returns to the initial position. At the same time, the right-angle retaining block 1321 drives the push rod 1324 to return to the initial position as well.

[0064] The purely mechanical square substrate clamping solution provided in this embodiment requires no additional power source or complex control timing, has a compact structure, and is reliable in operation.

[0065] An embodiment of the present invention also provides a substrate polishing method. The substrate polishing method of the present invention uses the substrate polishing unit 100 provided in the previous embodiment, which will be described below in conjunction with... Figure 8 This embodiment details the steps and working principle.

[0066] S101. Control the polishing head 10 to press the substrate onto the polishing pad.

[0067] Before polishing, the polishing head 10 is in a raised state, the top pin 1323 is in a low position under the action of the spring 3235, and the lower rod 3233 protrudes from the bottom surface of the retaining ring 131. At this time, the push rod 1324 and the right-angle retaining block 1321 are in the initial position, and the right-angle retaining block 1321 (especially the lower part 3212 of the right-angle retaining block) does not exceed the inner edge of the retaining ring 131 in the horizontal direction. That is, the structure and position of the retaining ring 131 remain unchanged and do not affect the positioning of the polishing head and the loading of the substrate.

[0068] During polishing, the polishing head 10 is pressed down onto the polishing pad 21. As the pressure decreases, the polishing pad 21 contacts the lower rod 3233 and, under the reaction force of the polishing pressure, lifts the top pin 1323 vertically upward. During the upward movement of the top pin 1323, the inclined surface of the top pin wedge block 3231 pushes the push rod wedge block 3241 through the ball bearing 52, converting the vertical movement into the horizontal inward movement of the push rod 1324. The push rod 1324 then pushes the lower part 3212 of the right-angle retaining block towards the center of the polishing head 10. When the polishing head 10 is pressed into place, the four right-angle retaining blocks 1321 work together to clamp the square substrate. At this time, the lower rod 3233 is completely contained in the retaining ring 131, and the bottom of the retaining ring 131 is in full contact with the polishing pad, without affecting the original polishing process.

[0069] S102. Introduce positive pressure into the air pressure chamber 118.

[0070] Before, after, or simultaneously with the four right-angle retaining blocks 1321 reaching the clamping position, positive pressure is introduced into the air pressure chamber 118, and the right-angle retaining blocks 1321 are stably pressed onto the polishing pad, thereby forming a fully clamped state in both the vertical and horizontal directions. In the fully clamped state, there is no relative movement between the square substrate and the retaining ring 131 throughout the polishing process. The polishing head 10 applies precise back pressure to the substrate through the air film assembly 12, thereby achieving high-quality chemical mechanical polishing without worrying about damage to the sharp corners of the square substrate.

[0071] S103. Control the rotation of the polishing head and its radial reciprocating movement along the polishing disk 20, and control the liquid supply unit 40 to spray polishing liquid onto the surface of the polishing pad 21.

[0072] S104. Introduce negative pressure into the air pressure chamber 118 to control the polishing head 10 to detach from the polishing pad.

[0073] After polishing, the polishing head 10 is lifted as a whole, and the top pin 1323 loses the pushing force of the polishing pad 21 and returns to its initial position downward under the action of the spring 3235. At the same time, negative pressure is applied in the air pressure chamber, and the reset structure drives the push rod 1324 and the right-angle holding block 1321 to return to their initial positions. The right-angle holding block 1321 and the substrate are re-formed with a gap, which facilitates the unloading of the substrate from the polishing head.

[0074] The polishing equipment 1000 of the present invention also includes functional modules such as a transmission unit, a positioning unit, and a cleaning unit. Their specific structures are not the focus of the present invention and will not be described in detail here.

[0075] Optionally, the polishing apparatus 1000 of the present invention further includes a controller for controlling the polishing unit 100 to perform the substrate polishing method of the present invention.

[0076] The above embodiments are only used to illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of the present invention, and the patent protection scope of the embodiments of the present invention should be defined by the claims.

Claims

1. A polishing head for polishing a square substrate, characterized in that, include: The base assembly, the air-supported membrane assembly mounted below the base assembly, and the retaining ring assembly, with the retaining ring assembly surrounding the air-supported membrane assembly; The retaining ring assembly includes a square annular retaining ring and clamping elements disposed at each corner of the retaining ring. Each corner of the retaining ring is provided with a structure for mounting the clamping element. The clamping element includes a right-angle retaining block, a top pin, and a push rod. The right-angle retaining block is disposed at the four corners of the square substrate. The top pin is slidably disposed in the retaining ring in the vertical direction, and a top pin wedge block is provided in the middle of the top pin, with the bottom protruding from the bottom surface of the retaining ring; the push rod is slidably disposed in the retaining ring in the horizontal direction, and a push rod wedge block is provided at one end of the push rod to cooperate with the top pin wedge block, so as to convert the vertical movement of the top pin wedge block into the horizontal movement of the push rod wedge block through the inclined surface cooperation, and the other end of the push rod faces the right-angle retaining block; The right-angle retaining block includes an upper part and a lower part. The upper part is fixedly connected to the base assembly, and the lower part is movably connected to the upper part. During polishing, the polishing head presses down, causing the polishing pad to generate a reaction force on the bottom of the top pin. The top pin responds to this reaction force and slides upward. Through the cooperation of the wedge block, the push rod moves horizontally towards the center of the retaining ring, pushing the lower part of the right-angle retaining block towards the center of the polishing head. The clamping elements at the four included angles work together to clamp the four corners of the square substrate with the right-angle retaining block. The retaining ring provides only the movement space for the lower part of the right-angle retaining block without providing vertical support or vertical sliding guidance for the lower part of the right-angle retaining block; and when the polishing head is pressed on the polishing pad, the top pin moves vertically upward until it is fully accommodated in the retaining ring, and the bottom surface of the retaining ring is in full contact with the polishing pad.

2. The polishing head according to claim 1, characterized in that, The top of the top pin is provided with an elastic reset member, which is used to drive the top pin to return to its initial position; the clamping element also includes a reset structure for driving the push rod and the lower part of the right-angle retaining block to return to their initial positions; after polishing is completed, in response to the release of the polishing pressure, the top pin slides downward under the action of the elastic reset member, and the push rod and the lower part of the right-angle retaining block are reset to release the four corners of the square substrate.

3. The polishing head according to claim 2, characterized in that, The top pin includes an upper rod that protrudes upward from the inclined surface of the top pin wedge block and a lower rod that protrudes downward from the horizontal bottom surface of the top pin wedge block. The elastic reset member is a spring sleeved on the upper rod, and at least a portion of the lower rod protrudes from the bottom surface of the retaining ring. The top pin also includes a top pin cover block, the bottom of which is provided with a receiving hole for accommodating the upper rod and the spring. The top pin cover block is fixedly disposed with the retaining ring.

4. The polishing head according to claim 3, characterized in that, One of the inclined surfaces of the top pin wedge block and the push rod wedge block is provided with a ball bearing mounting groove, and the other inclined surface is provided with a ball bearing track. Ball bearings are installed in the ball bearing mounting groove, and the ball bearings roll in the ball bearing track when the top pin wedge block and the push rod wedge block move relative to each other.

5. The polishing head according to claim 1, characterized in that, The right-angle retaining block has an L-shaped horizontal cross section. The push rod is arranged along the diagonal of the retaining ring, and its end opposite to the push rod wedge block is aligned with the outer corner of the L-shape. An avoidance structure is provided at the inner corner of the L-shape so that when the right-angle retaining block clamps the square substrate, the inner corner of the L-shape does not contact the corner of the substrate.

6. The polishing head according to claim 5, characterized in that, The avoidance structure can be any one of a chamfer, rounded corner, or notch.

7. A polishing unit, characterized in that, Includes the polishing head as described in any one of claims 1-6.

8. A polishing device, characterized in that, Includes the polishing unit as described in claim 7.

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