Vacuum chuck and square substrate polishing apparatus

Abstract

The application provides a vacuum adsorption disc and a square substrate grinding device, and belongs to the technical field of semiconductors. The vacuum adsorption disc is arranged in a rectangular shape, and comprises a disc area and corner areas. The disc area is arranged in the central region of the vacuum adsorption disc. Four corner areas are arranged; the corner areas are arranged at the four corners of the vacuum adsorption disc respectively; the corner areas and the disc area form a rectangle; and the height of the disc area is higher than the height of the corner areas. The square substrate grinding device provided by the application adopts a layered rectangular vacuum adsorption bearing structure with a central disc area matched with four independent corner areas, so that the four corners of the substrate do not bear uniform high pressure for a long time, the edge material removal rate can be consistent with the central region of the substrate, and the polishing uniformity of the whole substrate surface is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, and more specifically, relates to a vacuum adsorption disk and a square substrate grinding device. Background Technology

[0002] In semiconductor device manufacturing, chemical-mechanical planarization (CMP) is used to planarize the surface of substrates. The principle of CMP is to inflate an elastic membrane chamber within the polishing head, causing the sealed elastic membrane to expand and apply downward pressure to the wafer, thus achieving substrate planarization. Of the substrates used, 70% are circular, like wafers; the remaining 30% are quadrilateral panels, such as printed circuit board substrates, photomask substrates, and display panels. With the rapid development of display technology, the demand for high-precision planarization of non-circular components, such as square glass interposers and square silicon substrates, is increasingly urgent in fields such as advanced semiconductor packaging and microelectromechanical systems (MEMS) manufacturing.

[0003] However, when polishing square substrates, the following problems were found during the research and development and use process: During the polishing process, the right-angled area of ​​the substrate is at the edge of the rotational motion, with a large linear velocity gradient and complex polishing fluid distribution, which makes it easier to over-polish certain areas. Summary of the Invention

[0004] The purpose of this invention is to provide a vacuum adsorption plate and a square substrate grinding device, which aims to solve the problem that over-polishing easily occurs in the right-angle area of ​​the substrate when grinding square substrates in related technologies.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, a vacuum adsorption disk is provided, the vacuum adsorption disk being rectangular in shape, comprising: The circular area is located in the central region of the vacuum adsorption disk; There are four corner areas; the corner areas are respectively located at the four corners of the vacuum adsorption disk; the corner areas and the disk area form a rectangle; the height of the disk area is higher than the height of the corner areas.

[0006] In one possible implementation, the height difference between the disk area and the corner area is 50-400 μm.

[0007] In one possible implementation, multiple vacuum adsorption units are provided inside both the disk area and the corner area; the density of the vacuum adsorption units in the disk area is lower than the density of the vacuum adsorption units in the corner area; each vacuum adsorption unit operates independently, and the downward pressure in the corner area is controlled by controlling the number of working vacuum adsorption units in the corner area.

[0008] In one possible implementation, the vacuum adsorption unit includes: A vacuum adsorption chamber is disposed in the disc area or the corner area; one end of the vacuum adsorption chamber is flush with the surface of the disc area or the corner area and is provided with adsorption holes.

[0009] A plunger can be inserted into the vacuum adsorption chamber; when the plunger is inserted into the vacuum adsorption chamber, it blocks the vacuum adsorption chamber, causing the vacuum adsorption chamber to stop working.

[0010] In one possible implementation, a thin film is fixedly connected to the surface of the vacuum adsorption disk, and the thin film is provided with vent holes, which correspond one-to-one with the adsorption holes and are interconnected.

[0011] In one possible implementation, the thickness of the film is 0.6-0.9 mm.

[0012] In one possible implementation, the thin film comprises: The adhesive backing layer is fixedly attached to the surface of the vacuum adsorption disk; The PET layer is fixedly attached to the adhesive backing layer; A polyurethane layer is fixedly attached to the PET layer.

[0013] In one possible implementation, the thickness of the adhesive layer is 0.2-0.3 mm, the thickness of the PET layer is 0.2-0.3 mm, and the thickness of the polyurethane layer is 0.2-0.3 mm.

[0014] In a second aspect, a square substrate polishing apparatus is provided, including a polishing head, the polishing head including a vacuum adsorption disk as described in the first aspect.

[0015] In one possible implementation, a controller is also included, which is electrically connected to the drive unit and is used to control the drive unit to drive the plunger to insert into or slide out of the vacuum adsorption chamber.

[0016] The beneficial effects of the square substrate polishing apparatus provided by this invention are as follows: Compared with the prior art, the square substrate polishing apparatus of this invention adopts a layered rectangular vacuum adsorption bearing structure with a central disc area and four independent corner areas. The overall height of the central area is higher than that of the four corner areas, which allows the square substrate to form a slightly arched shape in the middle and a slightly raised shape at the four corners after adsorption. During the substrate polishing rotation, the four corner areas will not be in continuous close contact with the polishing pad, which can significantly reduce the effective polishing time at right angles and alleviate the problem of local over-polishing caused by the difference in edge linear velocity gradient. The four corners of the substrate will not be subjected to uniform high pressure for a long time, and the material removal rate at the edges can be consistent with that of the central area of ​​the substrate, effectively improving the polishing uniformity of the entire substrate surface.

[0017] The layered, varying heights disperse contact stress during substrate polishing, preventing stress concentration at the right corners of square substrates. Tiny gaps between the substrate corners and the polishing pad allow for continuous flow of polishing slurry at the corner contact interfaces, preventing slurry buildup or dry polishing. The lack of continuous high-pressure friction in the corner areas significantly reduces the probability of defects such as chipping, scratches, and other imperfections at the substrate corners.

[0018] The disc area serves as the primary support and adsorption zone, stably locking the main body of the substrate and preventing it from shifting or slipping during polishing rotation. The corner areas provide auxiliary adsorption and positioning, avoiding excessive downward pressure on the substrate edges while balancing substrate stability with edge polishing control requirements. The height difference structure eliminates the need for additional independent voltage regulation drive components; the structural shape alone achieves differentiated pressure on the substrate center and corners, simplifying the overall voltage regulation control logic and reducing the processing and maintenance costs of the equipment's components. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the vacuum adsorption disk provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the vacuum adsorption unit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the thin film provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the polishing head provided in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures: 11. Disc area; 12. Corner area; 13. Vacuum adsorption unit; 131. Vacuum adsorption chamber; 132. Plunger; 133. Drive component; 134. Adsorption hole; 2. Film; 21. Adhesive backing layer; 22. PET layer; 23. Polyurethane layer. Detailed Implementation

[0022] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0023] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0024] It should be further noted that the accompanying drawings and embodiments of the present invention mainly describe the concept of the present invention. Based on this concept, some specific forms and arrangements of connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, under the premise that those skilled in the art understand the concept of the present invention, they can implement the above-mentioned specific forms and arrangements in a well-known manner.

[0025] When a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0026] In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0027] The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself. The terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" 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 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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0028] For ease of description, spatial relative terms such as "above," "over," "on the upper surface," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative description used herein will be interpreted accordingly. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0029] In semiconductor device manufacturing, chemical-mechanical planarization (CMP) is used to planarize the surface of the substrate. The principle of CMP is to inflate the membrane (MM) zones within the polishing head, causing the sealed membrane to expand and apply downward pressure to the wafer, thus achieving substrate planarization. Of the substrates used, 70% are circular, such as wafers; the remaining 30% are quadrilateral panels, such as printed circuit board (PCB) substrates, photomask substrates, and display panels. With the rapid development of display technology, the demand for high-precision planarization of non-circular components, such as square glass interposers and square silicon substrates, is increasingly urgent in fields such as advanced semiconductor packaging and microelectromechanical systems (MEMS) manufacturing.

[0030] Many manufacturers have designed and developed panel polishing heads. However, when polishing square substrates, the following pain points have been found during the research and development and use process: First, during the polishing process, the right-angled areas of the panel are at the edge of the rotational motion, with a large linear velocity gradient and complex polishing fluid distribution, making it easier to over-polish certain areas; Second, during the loading or polishing process of square substrates, the panels often break due to collisions with the ceramic adsorption pads.

[0031] To address the aforementioned pain points, this invention provides a vacuum adsorption plate and a square substrate grinding device.

[0032] Reference Figures 1 to 3 The vacuum adsorption disk and the square substrate grinding device provided by the present invention will now be described. The vacuum adsorption disk is rectangular and includes a disk area 11 and corner areas 12.

[0033] The circular area 11 is located in the center of the vacuum adsorption disk. There are four corner areas 12; the corner areas 12 are located at the four corners of the vacuum adsorption disk; the corner areas 12 and the circular area 11 form a rectangle; the height of the circular area 11 is higher than the height of the corner areas 12.

[0034] Specifically, a circular area 11 is arranged at the center of the vacuum adsorption tray. The outer contour of the circular area 11 and the outer contour of the vacuum adsorption tray form an inscribed circle matching relationship. Four corner areas 12 are independently set at the four opposite corners of the vacuum adsorption tray. The four corner areas 12, together with the central circular area 11, form a complete rectangular support surface. The overall forming height of the circular area 11 is higher than the forming height of each corner area 12. After the substrate is placed on the surface of the vacuum adsorption tray and vacuum adsorption is completed, the main surface of the substrate will adhere to the higher circular area 11 to form the main support points. The four corners of the substrate only have slight contact support with the corner areas 12.

[0035] During the polishing process, the substrate exhibits a stress distribution with the center sinking and the four corners slightly raised. Tiny flow gaps naturally exist between the four corners of the substrate and the polishing pad, allowing the polishing fluid to continuously circulate through these gaps in the substrate's edge areas. The central disc area 11 bears the majority of the substrate's adsorption and support pressure, while the corner areas 12 only provide auxiliary restraint at the four corners. The right-angled areas of the substrate do not continuously bear high-intensity, uniform downward pressure, mitigating the problem of uneven material removal rates caused by differences in edge linear velocity during rotary polishing. The staggered partition structure eliminates the need for additional pressure adjustment components; the differential pressure effect between the center and corner areas of the substrate is achieved solely through the difference in their own forming height, reducing over-polishing caused by prolonged friction in the right-angled areas.

[0036] Compared with the prior art, the square substrate polishing apparatus provided by this invention adopts a layered rectangular vacuum adsorption bearing structure with a central disc area 11 and four independent corner areas 12. The overall height of the central area is higher than that of the four corner areas, which allows the square substrate to form a slightly arched shape in the middle and a slightly raised shape at the four corners after adsorption. During the substrate polishing rotation, the four corner areas will not be in continuous close contact with the polishing pad, which can significantly reduce the effective polishing time at right angles and alleviate the problem of local over-polishing caused by the difference in edge linear velocity gradient. The four corners of the substrate will not be subjected to uniform high pressure for a long time, and the material removal rate at the edges can be consistent with that of the central area of ​​the substrate, effectively improving the polishing uniformity of the entire substrate surface.

[0037] The layered, varying heights disperse contact stress during substrate polishing, preventing stress concentration at the right corners of square substrates. Tiny gaps between the substrate corners and the polishing pad allow for continuous flow of polishing slurry at the corner contact interfaces, preventing slurry buildup or dry polishing. The lack of continuous high-pressure friction in the corner areas significantly reduces the probability of defects such as chipping, scratches, and other imperfections at the substrate corners.

[0038] The disc area 11 serves as the primary support and adsorption area, stably locking the main body of the substrate and preventing it from shifting or slipping during polishing rotation. The corner area 12 provides auxiliary adsorption and positioning, avoiding excessive downward pressure on the substrate edges while balancing substrate stability and edge polishing control requirements. The height difference structure eliminates the need for additional independent voltage regulation drive components; the structural shape alone achieves differentiated pressure on the substrate center and corners, simplifying the overall voltage regulation control logic and reducing the processing and maintenance costs of the equipment's supporting structures.

[0039] In one possible implementation, the height difference between the disk region 11 and the corner region 12 is 50-400 μm.

[0040] For example, the height difference between the disk area 11 and the corner area 12 is 50μm. This height difference is set to this value to avoid insufficient lifting of the substrate corners due to a small height difference, and to prevent the substrate corners from still being in contact with the polishing pad over a large area, thus failing to alleviate over-polishing defects. After the substrate is placed and adsorbed, only a slight corner lifting gap is formed, with the central area still bearing the main load, and only a small contact space remaining at the corners. A small amount of polishing fluid can penetrate between the substrate corners and the polishing pad, reducing the duration of continuous dry friction in the corner area 12 to some extent. The difference between the material removal rate at the substrate edge and the central area can be slightly reduced, decreasing the probability of minor scratches at the right angles of the square substrate. The small height difference will not cause significant bending deformation of the substrate as a whole, ensuring the overall flatness of the substrate after adsorption and preventing positioning offset problems caused by excessive height difference, such as central depression or excessive corner suspension.

[0041] For example, the height difference between the disk area 11 and the corner area 12 is set to 200μm. This value is chosen to balance the lifting height of the substrate corners with the overall adsorption stability of the substrate, taking into account both polishing uniformity and substrate fixation effect. After the substrate is adsorbed and fixed, a moderate lifting gap can be formed at the four corners. The size of the gap can ensure that the polishing liquid flows continuously and stably at the corner contact interface, without the polishing liquid stagnation or interruption. The effective contact area between the corner area 12 and the polishing pad is significantly reduced, and the removal rate deviation caused by the difference in the linear velocity of the corners during the rotary polishing process can be significantly neutralized. The friction pressure on the right-angle parts of the substrate is greatly reduced, and the defects of bumping, chipping, and over-polishing of the edges can be effectively suppressed. The moderate height difference will not cause excessive bending stress on the substrate. The vacuum adsorption unit 13 can stably lock the substrate body, and the substrate will not slip or misalign during the polishing rotation operation. At the same time, it can achieve differentiated pressure between the center and the corners without the need for an additional pressure regulating structure, which is suitable for the polishing processing needs of most conventional square substrates.

[0042] For example, the height difference between the disk area 11 and the corner area 12 is set to 400μm. This value is chosen to maximize the gap between the four corners of the substrate and the polishing pad, and to minimize the polishing contact intensity in the corner area 12. After the substrate is adsorbed, the four corners are significantly raised, and the corners are only supported by the vacuum adsorption unit 13, with almost no continuous frictional contact between the corners and the polishing pad. The polishing slurry can fully cover the entire edge area of ​​the substrate, completely eliminating surface defects caused by dry grinding at the corners and the accumulation and deterioration of the polishing slurry. The material removal rate at the corners of the substrate can approach the center area of ​​the substrate, and the surface uniformity of the entire substrate after polishing reaches the optimal level. The large height difference places basic requirements on the rigidity of the substrate itself, which can be adapted to square substrates with larger thickness and less bending, and can completely avoid various appearance defects caused by long-term high-pressure friction at right angles. At the same time, under this drop structure, the central disk area 11 bears concentrated pressure, the substrate body is firmly adsorbed, and the substrate will not wobble or shift during high-speed rotation polishing. It is only not suitable for ultra-thin and easily deformable substrate types.

[0043] In one possible implementation, multiple vacuum adsorption units 13 are provided inside both the disk area 11 and the corner area 12; the density of the vacuum adsorption units 13 in the disk area 11 is lower than the density of the vacuum adsorption units 13 in the corner area 12; each vacuum adsorption unit 13 works independently, and the downward pressure of the corner area 12 is controlled by controlling the number of working vacuum adsorption units 13 in the corner area 12.

[0044] Specifically, multiple independently arranged vacuum adsorption units 13 are arranged in the central disc area 11 and the corner areas 12 of the four corners of the vacuum adsorption plate. The density of the vacuum adsorption units 13 in the disc area 11 is lower than that in the corner areas 12. Each vacuum adsorption unit 13 can start and stop independently, and there will be no situation where the on / off state of one point affects the other adsorption points simultaneously. When the equipment is running, the number of vacuum adsorption units 13 working in the corner areas 12 can be adjusted individually according to the actual needs of polishing the square substrate. This changes the overall adsorption pull of the corner areas 12 on the four corners of the substrate, and indirectly adjusts the downward pressure transmitted from the corners of the substrate to the polishing pad.

[0045] The disc area 11 uses lower-density adsorption units to stably support the main surface of the substrate, providing a uniform and gentle basic adsorption force and preventing deformation of the substrate center due to excessive adsorption tension. The corner area 12 uses higher-density adsorption units to form a flexibly adjustable auxiliary limiting structure, reducing unrestrained shaking at the four corners of the substrate. At the same time, by turning off some adsorption units, the overall pressure at the corners is reduced, decreasing the frictional contact intensity between the right-angle areas of the substrate and the polishing pad. The zoned differential density combined with the independently controllable adsorption unit structure eliminates the need for additional pressure adjustment drive components. Differential control of the pressure at the center and corners of the substrate can be achieved simply by switching the number of working corner adsorption units, simultaneously improving the overall adsorption firmness and edge polishing uniformity of the substrate, and reducing the probability of scratches and dents at the corners of the substrate.

[0046] In one possible implementation, the vacuum adsorption unit 13 includes a vacuum adsorption chamber 131, a plunger 132, and a drive element 133.

[0047] A vacuum adsorption chamber 131 is disposed in the disc area 11 or the corner area 12; one end of the vacuum adsorption chamber 131 is flush with the surface of the disc area 11 or the corner area 12, and is provided with an adsorption hole 134. A plunger 132 can be inserted into the vacuum adsorption chamber 131; when the plunger 132 is inserted into the vacuum adsorption chamber 131, it blocks the vacuum adsorption chamber 131, causing the vacuum adsorption chamber 131 to stop working. The driving component 133 is connected to the plunger and is used to drive the plunger 132 to insert into or slide out of the vacuum adsorption chamber 131.

[0048] Specifically, the vacuum adsorption unit 13 includes a vacuum adsorption chamber 131, a plunger 132, and a driving component 133. The vacuum adsorption chamber 131 is integrally formed and arranged inside the disc area 11 or the four corner areas 12 of the vacuum adsorption disk. An adsorption hole 134 is formed on the side of the vacuum adsorption chamber 131 facing the substrate, and the adsorption hole 134 can form a negative pressure adsorption channel with the substrate. The driving component 133 is connected to the plunger 132, and the driving component 133 can output a linear driving force to drive the plunger 132 to reciprocate along the internal space of the vacuum adsorption chamber 131. Specifically, the driving component 133 can be a cylinder or an electric telescopic rod.

[0049] When the driving element 133 controls the plunger 132 to be inserted into the vacuum adsorption chamber 131, the outer wall of the plunger 132 can completely block the internal passage of the vacuum adsorption chamber 131, and a negative pressure environment cannot be formed at the adsorption hole 134. The corresponding vacuum adsorption unit 13 then stops adsorption operation. When the driving element 133 controls the plunger 132 to be pulled out from inside the vacuum adsorption chamber 131, the plunger 132 releases the blockage of the passage of the vacuum adsorption chamber 131, and the negative pressure airflow can be output normally through the adsorption hole 134. The vacuum adsorption unit 13 then resumes adsorption operation.

[0050] Each vacuum adsorption unit 13 is matched with an independent drive component and plunger 132. The start and stop actions of each vacuum adsorption unit 13 do not interfere with each other. The operator can individually adjust the operating status of the drive components 133 corresponding to any number of vacuum adsorption units 13 in the corner area 12, thereby flexibly adjusting the overall adsorption pressure exerted by the corner area 12 on the four corners of the substrate. The plunger 132 maintains a close sliding fit with the inner wall of the vacuum adsorption chamber 131, maintaining a sealing effect during sliding and preventing negative pressure gas leakage, thus ensuring the stability of the adsorption state switching response. The entire structure relies on the mechanical sealing of the plunger 132 to achieve the switching of the adsorption path, eliminating the need for an additional independent negative pressure control valve group, simplifying the overall layout of the vacuum circuit, and reducing the assembly and maintenance difficulty of the equipment's gas circuit components.

[0051] In one possible implementation, a thin film 2 is fixedly connected to the surface of the vacuum adsorption disk. The thin film 2 is provided with vent holes, which correspond one-to-one with the adsorption holes 134 and are connected to each other.

[0052] Specifically, a thin film 2 is attached and fixed to the entire bearing surface of the vacuum adsorption disk. The film 2 completely covers the entire plate surface of the disc area 11 and the four corner areas 12. Several through-holes are opened inside the film 2. The position of each vent is aligned with the adsorption hole 134 on the vacuum adsorption disk. The two are interconnected to form a complete negative pressure ventilation channel.

[0053] The thin film 2 adheres to the bottom surface of the substrate after vacuum adsorption, buffering the rigid contact between the substrate and the hard adsorption disk body, preventing scratches and damage caused by direct friction between the bottom surface of the substrate and the surface of the adsorption disk, and preventing collision damage between the substrate and the vacuum adsorption disk. The negative pressure airflow generated by the vacuum adsorption unit 13 during operation can sequentially pass through the adsorption hole 134 and the vent hole to act on the substrate surface. The vent hole does not block the negative pressure transmission path and does not weaken the adsorption and fixation ability of the vacuum adsorption unit 13 on the substrate. The thin film 2 is evenly laid throughout the entire bearing area. The height difference between the disc area 11 and the corner area 12 can be completely transmitted to the upper surface of the thin film 2. The thin film 2 synchronously forms a shape that is high in the middle and low at the four corners with the partition height, still allowing the square substrate to maintain a tight fit in the middle and a slightly raised four corners after adsorption.

[0054] In one possible implementation, the thickness of the thin film 2 is 0.6-0.9 mm.

[0055] For example, the overall thickness of film 2 is set to 0.6mm. This thickness is chosen to maintain the overall rigidity of film 2, avoid excessive pressure collapse due to excessive thickness, and fully preserve the height difference structure between the disc area 11 and the corner area 12. After film 2 is adhered to the surface of the vacuum adsorption disk, the thin layer structure does not significantly weaken the corner lifting effect caused by the partition height difference. After the substrate is adsorbed and fixed, the four corners can still form a stable micro-gap with the polishing pad. The air vent channel length of the thin layer structure of film 2 is short, and the negative pressure airflow transmission resistance is lower. The adsorption force generated by each group of vacuum adsorption units 13 can quickly and evenly act on the bottom surface of the substrate without local adsorption force attenuation. The thin film 2 itself has small deformation, and the substrate will not undergo unnecessary sinking or displacement during polishing rotation. It can stably control the polishing removal rate of the substrate edge. At the same time, the buffering effect of the thin layer material can basically isolate the direct contact between the substrate and the rigid adsorption disk, slightly reducing the risk of scratches on the bottom surface of the substrate. It is only suitable for various square substrates with high surface flatness and high rigidity.

[0056] For example, the overall thickness of film 2 is set to 0.75mm. This thickness is chosen to balance the buffering and shock absorption capacity of film 2 with the structural deformation range, taking into account both the substrate protection effect and the partition height difference forming effect. Film 2 has a moderate thickness, which can effectively buffer the vibration and impact generated during the polishing process by means of its own flexible material, reducing edge chipping defects caused by collision between the substrate corners and the polishing pad, without completely offsetting the height difference between the disk area 11 and the corner area 12 due to excessive thickness. The internal ventilation holes of film 2 maintain a moderate passage length, and the negative pressure airflow is delivered smoothly and without obstruction. The downward pressure adjustment effect achieved by adjusting the number of working vacuum adsorption units 13 in the corner area 12 can be completely transmitted to the four corners of the substrate. At this thickness, film 2 only undergoes slight deformation under pressure, the support state of the disk area 11 in the middle of the substrate is not destroyed, the overall adsorption and positioning of the substrate is stable, and the uniformity of removal of the board surface is continuously guaranteed throughout the polishing process, which can be adapted to most square substrate polishing processing scenarios with conventional thickness and conventional materials.

[0057] For example, the overall thickness of film 2 is set to 0.9 mm. This thickness is chosen to maximize the flexible buffering performance of film 2, significantly reducing damage to the substrate caused by vibration and hard contact during polishing. A thicker film 2 can fully absorb the vibration generated during polishing. When the right-angle part of the substrate accidentally touches the polishing pad, the flexible layer of film 2 can offset the impact, significantly reducing the probability of substrate bumps and corner breakage. Film 2 has a larger overall deformation space, which can adapt to square substrates with slight surface unevenness, allowing the bottom surface of the substrate to fully adhere to film 2, ensuring that the vents can stably output negative pressure to complete the adsorption and fixation. The film 2 thickness reaches the upper limit, which will result in a slight weakening effect of height difference. Therefore, it is necessary to adjust the number of vacuum adsorption units 13 in the corner area 12 to reduce the corner adsorption pull to compensate for the reduction of lifting gap caused by the deformation of film 2. This thickness specification is more suitable for polishing ultra-thin, brittle, and easily damaged square substrates, and can provide maximum all-round protection for the substrate.

[0058] In one possible implementation, the film 2 includes an adhesive layer 21, a PET layer 22, and a polyurethane layer 23.

[0059] The adhesive backing layer 21 is fixedly connected to the surface of the vacuum suction tray. The PET layer 22 is fixedly connected to the adhesive backing layer 21. The polyurethane layer 23 is fixedly connected to the PET layer 22.

[0060] Specifically, the adhesive layer 21 is attached to the carrier plate of the vacuum adsorption plate. The adhesive layer 21 has a uniformly distributed adhesive that allows the film 2 to be flat and firmly attached to the plate surface, preventing the film 2 from slipping or misaligning during polishing rotation. The adhesive layer 21 has the physical property of being easy to peel off, and the film 2 can be completely peeled off and replaced after wear and aging, without leaving any adhesive impurities on the surface of the vacuum adsorption plate.

[0061] PET is made of polyethylene terephthalate, a widely used thermoplastic polyester with excellent dimensional stability and resistance to stretching and deformation under pressure and temperature. The interlayer evenly distributes the pressure from the square substrate, preventing localized collapse of the film 2 and ensuring precise alignment between the vent holes in the padding and the suction holes 134 of the vacuum adsorption tray, maintaining unobstructed negative pressure airflow. The interlayer also isolates the surface polyurethane from direct contact with the underlying adhesive, preventing performance failure due to prolonged contact with the adhesive. Its moderate rigidity provides shaping support for the entire film 2, ensuring the complete transfer of the stepped height difference between the center and corners of the vacuum adsorption tray to the bottom of the substrate.

[0062] Polyurethane (Polyethylene Terephthalate) is the mainstream material for conventional polishing pads. This material has good compatibility with polishing systems and will not leach impurities that contaminate the substrate during chemical mechanical planarization (CMP) processes. Polyurethane is soft and highly elastic, forming a flexible buffer zone between the substrate and the hard ceramic vacuum adsorption pad. During loading and polishing, it can offset the hard impacts of collisions between the substrate and the pad surface, significantly reducing the probability of substrate chipping and breakage. Polyurethane exhibits outstanding resistance to abrasive corrosion and wear, and is not prone to damage or swelling even after prolonged contact with polishing slurries. Furthermore, it can work with the stepped height difference of the vacuum adsorption pad to create a support structure that adapts to the substrate, preserving lifting gaps at the four corners of the substrate and synergistically optimizing the overall polishing uniformity of the substrate.

[0063] In one possible implementation, the thickness of the adhesive layer 21 is 0.2-0.3 mm, the thickness of the polyurethane layer 23 is 0.2-0.3 mm, and the thickness of the PET layer 22 is 0.2-0.3 mm.

[0064] For example, the thickness of the adhesive backing layer 21 of the film 2 is set to 0.2mm. Using this minimum thickness reduces the overall amount of adhesive used, preventing excessive adhesive thickness from causing pressure overflow and clogging of the adsorption holes 134 on the surface of the vacuum adsorption disk. The thin adhesive layer makes uniform coating easier to control, and after bonding, no excess adhesive layer will accumulate between the film 2 and the disk surface. The thin overall thickness of the adhesive backing layer 21 does not negate the height difference structure formed between the circular disk area 11 and the corner area 12, allowing for complete transmission of the stepped support shape and ensuring a stable lifting gap at the four corners after adsorption of the square substrate. The thin adhesive backing layer has lower peel resistance, allowing for complete removal of the padding layer when the film 2 is worn and replaced, minimizing adhesive residue on the disk surface and reducing maintenance workload for cleaning the adsorption holes 134. This thickness of adhesive provides basic bonding strength, meeting the fixing requirements of the film 2 at normal polishing speeds without causing padding slippage. It is suitable for polishing conventional rigid square substrates, with only a slight decrease in bonding stability under high-speed substrate rotation and significant vibration.

[0065] For example, the thickness of the adhesive backing layer 21 of the film 2 is set to 0.25mm. This intermediate thickness balances the bonding strength and the risk of adhesive overflow. The moderate adhesive thickness improves the tightness of the adhesion between the film 2 and the vacuum adsorption pad, and the minor vibrations generated during polishing will not cause localized detachment or lifting of the pad. The adhesive backing layer 21 has a uniform adhesive distribution, and under pressure, there will be no situation where adhesive overflow on one side blocks the vent holes. The negative pressure airflow can smoothly pass through the vent holes and adsorption holes 134 to form a stable adsorption force. This thickness will not overfill the height difference between the disk area 11 and the corner area 12, and the lifting gap at the four corners of the substrate can maintain a moderate size, allowing the polishing liquid to continuously flow between the corners of the substrate and the polishing pad. The adhesive backing layer 21 has moderate peeling difficulty. When replacing the film 2, the pad can be completely peeled off without worrying about insufficient adhesive strength causing the pad to shift during polishing. It is suitable for most CMP polishing processing scenarios of conventional square substrates, and has stronger overall adaptability.

[0066] For example, the thickness of the adhesive layer 21 of the film 2 is set to 0.3mm. Using this maximum thickness maximizes the bonding area and strength of the adhesive layer 21. For high-speed polishing and high-vibration processing conditions, it effectively prevents localized edge lifting and overall slippage of the film 2, ensuring the pad's fixation effect during long-term continuous polishing operations. A thicker adhesive layer can fill in minor imperfections on the surface of the vacuum adsorption disk, allowing the film 2 to completely adhere to all parts of the disk surface, avoiding uneven negative pressure adsorption caused by localized gaps. Reaching the maximum thickness of the adhesive layer 21 slightly weakens the height difference between the circular area 11 and the corner area 12, and the lifting gap at the four corners of the substrate will slightly decrease. This gap change can be compensated by reducing the number of vacuum adsorption units 13 deployed in the corner area 12, maintaining uniform edge polishing. This thickness requires slightly greater external force to peel off the adhesive; slow peeling during operation avoids adhesive breakage and residue, making it more suitable for polishing large-sized, heavy square substrates, and able to withstand the risk of the pad detaching due to the substrate's own weight.

[0067] For example, the PET layer thickness is set to 0.2mm. Selecting this lower limit thickness can reduce the overall rigid support volume of the pad layer, without excessively increasing the overall support rigidity of the substrate. The thin polyethylene terephthalate layer will not fill the height difference between the disk area 11 and the corner area 12 in large quantities, and can completely preserve the flow gap between the four corners of the substrate and the polishing pad. The thin PET layer will not significantly increase the passage length of the vent holes, and the resistance is smaller when the negative pressure airflow passes through the film 2. The adsorption force output by each set of vacuum adsorption units 13 can be evenly transmitted to the bottom surface of the substrate, and there will be no local adsorption force attenuation imbalance. This thickness of PET layer has basic shaping ability, which can prevent the surface polyurethane from collapsing on a large area after being compressed, and can maintain the alignment accuracy of the vent holes and the adsorption holes 134 of the vacuum adsorption disk. The thin layer structure is lightweight and will not increase the adhesive load of the backing layer 21. It is suitable for polishing conditions of square substrates with sufficient rigidity and large thickness. Only under long-term high-speed grinding vibration environment will the probability of slight deformation of the pad layer increase slightly.

[0068] For example, the PET layer thickness is set to 0.25mm. This intermediate thickness balances the shaping and support effect of the padding layer with the flexible buffer space. The moderately thick polyethylene terephthalate layer can evenly distribute the pressure applied to the substrate, preventing significant indentation or deformation at locally stressed areas and ensuring unobstructed ventilation channels throughout. This thickness does not excessively offset the height difference caused by the partitioning of the vacuum adsorption plate, maintaining a moderate gap at the four corners of the substrate. The polishing slurry can circulate stably through the contact interface at the substrate corners, effectively alleviating the problem of over-polishing at the edges. The PET layer has moderate rigidity, which can both isolate the polyurethane layer 23 from direct contact with the adhesive layer 21 to prevent material swelling and failure, and avoid amplifying the hard friction between the substrate and the padding layer due to excessive hardness. With different working numbers of corner vacuum adsorption units 13, the pressure at the corners can be flexibly adjusted, adapting to most conventional square substrate CMP polishing processing scenarios, resulting in optimal overall adaptability.

[0069] For example, the thickness of the PET layer 22 is set to 0.3mm. Selecting this upper limit thickness can maximize the overall shaping stability of the pad layer. The thicker polyethylene terephthalate has stronger tensile and deformation resistance, and will not stretch or shift during long-term grinding operations. The vent holes and adsorption holes 134 can always be precisely aligned, avoiding the problem of misalignment and blockage of negative pressure channels. The thicker PET layer has a stronger effect in distributing pressure, which can resist the local heavy pressure caused by the weight of the large-size substrate, reduce the uneven adsorption force caused by the collapse of the polyurethane layer 23 under pressure, and at the same time enhance the isolation effect, completely blocking the chemical reaction between the surface polyurethane and the bottom adhesive. This thickness will slightly weaken the height difference between the disk area 11 and the corner area 12, and the gap of the substrate corner lifting will be slightly reduced. The gap change can be compensated by reducing the corner adsorption pull force by turning off part of the vacuum adsorption unit 13 in the corner area 12. The thicker support structure is more suitable for ultra-thin, brittle, and easily deformable square substrates, and can effectively suppress the corner chipping defects caused by substrate bending.

[0070] For example, the thickness of the polyurethane layer 23 is set to 0.2 mm. Selecting this lower limit thickness can reduce the compression deformation of the polyurethane layer 23 itself, and will not significantly fill the height difference formed by the disk area 11 and the corner area 12. After the substrate is adsorbed, the flow gap between the four corners and the polishing pad can be completely preserved, and the polishing slurry can flow stably through the edge and corner interface of the substrate to alleviate the over-polishing problem. The passage distance of the vent holes inside the thin polyurethane layer 23 is shorter, the resistance of negative pressure airflow is smaller, and the adsorption force output by each vacuum adsorption unit 13 can act evenly on the bottom surface of the substrate, without the phenomenon of local adsorption force attenuation and imbalance. The polyurethane material itself will not release impurities to contaminate the substrate during CMP processing. The thin layer structure can also reduce the swelling volume caused by long-term wetting of the polishing slurry, and the overall cleanliness of the pad layer is easier to maintain. This thickness of polyurethane layer 23 can only provide basic buffer protection effect and can be adapted to polishing operations of square substrates with high rigidity and large thickness. If the substrate is brittle, the probability of minor damage caused by edge collisions under high-speed grinding vibration will increase slightly.

[0071] For example, the thickness of the polyurethane layer 23 is set to 0.25mm. This intermediate thickness balances the flexible buffering capacity with the height difference retention effect. The moderately thick polyurethane layer 23 only undergoes slight compression under pressure, which does not significantly offset the height difference caused by the partitioning of the vacuum adsorption pad. The gap size of the substrate corner lifting is moderate, and the circulation of polishing fluid is stable. The elastic buffering performance of the polyurethane layer 23 is fully utilized, which can effectively offset the impact caused by accidental contact between the substrate and the polishing pad, and significantly reduce the probability of defects such as substrate chipping and scratches. This thickness does not excessively prolong the length of the venting channel, and the negative pressure airflow is smooth and unobstructed. With the independently adjustable corner vacuum adsorption unit 13, the pressure on the substrate corners can be flexibly adjusted, which is suitable for the chemical mechanical polishing conditions of most conventional square substrates, and the overall performance is optimal.

[0072] For example, the thickness of the polyurethane layer 23 is set to 0.3 mm. Selecting this upper limit thickness can maximize the flexibility, buffering, and shock absorption capabilities of the polyurethane layer 23. The thick polyurethane layer can fully absorb the vibration and impact generated by the grinding process, forming all-round flexible protection for ultra-thin and brittle square substrates, significantly reducing the occurrence of edge and corner breakage. The polyurethane material does not have the problem of impurity precipitation, and the thick structure has a longer resistance to the corrosion and friction wear of polishing slurry, effectively extending the overall service life of the film 2. The polyurethane layer 23 of this thickness has a relatively larger compression amount, which will slightly weaken the height difference between the disk area 11 and the corner area 12, and slightly reduce the lifting gap at the four corners of the substrate. The gap change can be compensated by reducing the corner adsorption pull force by turning off part of the vacuum adsorption unit 13 in the corner area 12. The thick polyurethane layer is more suitable for high-precision polishing of thin and easily deformable substrates, and can avoid the problem of uneven removal rate caused by substrate bending.

[0073] The second aspect provides a square substrate polishing apparatus, including a polishing head, the polishing head including a vacuum adsorption disk as described in the first aspect.

[0074] Reference Figure 4 For example, the polishing head includes: an air intake assembly, a sealing ring, a sealing pressure plate, a flexible carrier, a rigid carrier, a retaining ring, a vacuum adsorption disk, and a thin film. It employs a square structure for the polishing process, forming a morphology that matches the panel, thus saving considerable space in the device.

[0075] In one possible implementation, a controller is also included. The controller is electrically connected to the drive element 133 and is used to control the drive element 133 to drive the plunger 132 to insert into or slide out of the vacuum adsorption chamber 131.

[0076] The controller adjusts the operating status of the driving components 133 corresponding to any number of vacuum adsorption units 13 in the corner area 12, thereby flexibly adjusting the overall adsorption pressure of the corner area 12 acting on the four corners of the substrate.

[0077] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0078] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0079] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

Claims

1. A vacuum adsorption disk, characterized in that, The vacuum adsorption disk is rectangular and includes: The circular area is located in the central region of the vacuum adsorption disk; There are four corner areas; the corner areas are respectively located at the four corners of the vacuum adsorption disk; the corner areas and the disk area form a rectangle; the height of the disk area is higher than the height of the corner areas.

2. The vacuum adsorption disk as described in claim 1, characterized in that, The height difference between the disk area and the corner area is 50-400 μm.

3. The vacuum adsorption disk as described in claim 1, characterized in that, Multiple vacuum adsorption units are provided inside both the disc area and the corner area; the density of the vacuum adsorption units in the disc area is lower than that in the corner area; each vacuum adsorption unit works independently, and the downward pressure in the corner area is controlled by controlling the number of working vacuum adsorption units in the corner area.

4. The vacuum adsorption disk as described in claim 3, characterized in that, The vacuum adsorption unit includes: A vacuum adsorption chamber is disposed in the disc area or the corner area; one end of the vacuum adsorption chamber is flush with the surface of the disc area or the corner area and is provided with adsorption holes; A plunger can be inserted into the vacuum adsorption chamber; when the plunger is inserted into the vacuum adsorption chamber, it blocks the vacuum adsorption chamber, causing the vacuum adsorption chamber to stop working; A driving component, connected to the plunger, is used to drive the plunger to insert into or slide out of the vacuum adsorption chamber.

5. The vacuum adsorption disk as described in claim 4, characterized in that, A thin film is fixedly connected to the surface of the vacuum adsorption disk. The thin film has ventilation holes, which correspond one-to-one with the adsorption holes and are interconnected.

6. The vacuum adsorption disk as described in claim 5, characterized in that, The thickness of the film is 0.6-0.9 mm.

7. The vacuum adsorption disk as described in claim 5, characterized in that, The thin film includes: The adhesive backing layer is fixedly attached to the surface of the vacuum adsorption disk; The PET layer is fixedly attached to the adhesive backing layer; A polyurethane layer is fixedly attached to the PET layer.

8. The vacuum adsorption disk as described in claim 7, characterized in that, The thickness of the adhesive backing layer is 0.2-0.3 mm, the thickness of the PET layer is 0.2-0.3 mm, and the thickness of the polyurethane layer is 0.2-0.3 mm.

9. A square substrate grinding apparatus, characterized in that, Includes a polishing head, the polishing head comprising a vacuum adsorption disk as described in any one of claims 1 to 8.

10. The square substrate grinding apparatus as described in claim 9, characterized in that, It also includes a controller, which is electrically connected to the drive unit, and the controller is used to control the drive unit to drive the plunger to insert into or slide out of the vacuum adsorption chamber.

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