Large-size photomask quartz glass substrate polishing device

Abstract

The invention relates to the technical field of photomask preparation, and aims to solve the technical problems of low yield, low processing precision and the like. In order to solve the technical problem, the invention provides the large-size photomask quartz glass substrate polishing device. The device comprises a workpiece rotation supporting assembly which is slidably connected to the top of one end of a bottom supporting piece in the X direction in the horizontal plane; a mounting groove is formed in a supporting disc of the workpiece rotary supporting assembly; the double-shaft grinding disc assembly is slidably connected to the top of the other end of the bottom supporting piece in the Y direction. The double-shaft grinding disc assembly comprises a rotatable polishing disc; the axis of the polishing disc is flush with the axis of the supporting disc in height. The polishing disc and the supporting disc are arranged in the sealed cabin; the cooling circulation system is used for supplying polishing liquid to the supporting disc and the polishing disc. Wherein the workpiece rotation supporting assembly slides towards the double-shaft grinding disc assembly and is used for clamping a to-be-machined workpiece; the polishing disc and the supporting disc rotate in the plane perpendicular to the horizontal plane. The machining precision and the yield are improved.

Description

Technical Field

[0001] The invention relates to the technical field of photomask preparation, in particular to a large-size photomask quartz glass substrate polishing device. Background Art

[0002] The pattern transfer master in the microelectronics manufacturing process, also known as the photomask, photomask, photolithography mask, etc., is a pattern transfer tool or master in the microelectronics manufacturing process, and is the carrier of intellectual property information such as graphic design and process technology. In the photolithography process, the mask is the carrier of the design pattern. Through photolithography, the design pattern on the mask is transferred to the photoresist, and then through etching, the pattern is engraved on the substrate, thereby realizing the transfer of the pattern to the silicon wafer. The function is similar to the "negative film" of a traditional camera, carrying the core technical parameters of the electronic circuit.

[0003] Taking the manufacturing of thin-film transistor liquid crystal displays (TFT-LCD) as an example, the mask's exposure and masking function is used to sequentially expose and transfer the designed thin-film transistor (TFT) array and color filter pattern to the glass substrate in the order of the thin-film transistor's film layer structure, ultimately forming a display device with multiple film layers stacked on top of each other. Taking wafer manufacturing as an example, its manufacturing process requires multiple exposure processes, using the mask's exposure and masking function to form gates, source and drain electrodes, doping windows, electrode contact holes, etc. on the surface of semiconductor wafers. The mask is an important component in the photolithography process, and its performance has a significant impact on photolithography.

[0004] Synthetic quartz glass is widely used in semiconductors, precision optics and other fields due to its extremely excellent optical properties and thermal shock resistance, extremely low thermal expansion coefficient and electrical conductivity. Synthetic quartz mask is a blank photomask substrate made from synthetic quartz ingots. It has high chemical stability, high hardness, low thermal expansion coefficient, and high light transmittance (especially in the ultraviolet band). It is often used as a photomask substrate for IC, LSI large FPD high-precision devices. At present, the plane processing of quartz glass is mainly through diamond grinding tools to grind a certain thickness to make it have a certain degree of roughness, flatness, parallelism, etc., and then polishing and finishing by aligning the polishing abrasive to finally meet the requirements of the finished product. The photomask quartz glass substrate also uses the same processing method.

[0005] In the processing of photomask quartz glass substrates, the control of polishing flatness is particularly important. For example, in the lithography technology using an ArF laser source with a wavelength of 193nm and in the lithography technology based on the combination of an ArF laser source and an immersion technique, the quartz glass substrate used as a photomask needs to have good flatness. If the exposure surface is not flat during exposure, the displacement of the focus on the silicon wafer will cause the pattern consistency to deteriorate, making it impossible to form fine patterns. Taking the G8 generation TFT-LCD photomask quartz glass substrate as an example, its diagonal size is close to 1.9m or more, the thickness is between 8 and 14mm, and its flatness requirement is no more than 40μm. Due to its thin thickness and large area, it is extremely difficult to process.

[0006] The traditional processing method is to use cutting equipment to cut a quartz sheet with a certain thickness from a synthetic quartz ingot whose shape has been milled and formed. The equipment for cutting large-size quartz sheets can only achieve an optimal cutting flatness of less than 100μm, and the cutting accuracy is limited. After cutting, it needs to go through a grinding process. The grinding process is as follows: use one side as the reference surface, grind the other side, and grind the two sides alternately. At this time, the flatness is often controlled at 80~90μm. In the subsequent stage, the quartz sheet needs to be fixed by fixture clamping or vacuum adsorption, and ground on a horizontally placed radially rotating polishing disc with polishing abrasives. The radius of the polishing disc is required to be no less than the diagonal diameter of the quartz sheet. This step requires the flatness of the quartz sheet to be controlled within 40μm, usually within 20μm. After polishing one side, turn the quartz sheet over and polish the other side until it meets the requirements, and then go through cleaning and coating processes to finally form a sheet.

[0007] The problems with traditional polishing methods are: warping and deformation occur during processing, which seriously affects the yield of polishing processing; slight deformation occurs due to clamping force and heat, resulting in changes in the accuracy of the quartz plate after the plate is removed, affecting the accuracy of the finished product; the production and processing difficulties of the polishing plate are extremely high, and the cost is high. Summary of the invention

[0008] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned problems existing in the prior art.

[0009] In order to solve the above technical problems, the present invention provides a large-size photomask quartz glass substrate polishing device, comprising: Bottom support member; The workpiece rotary support assembly is slidably connected to the top of one end of the bottom support member in the horizontal plane along the X direction; the workpiece rotary support assembly includes a rotatable support plate; the plate surface of the support plate is provided with a mounting groove for mounting the workpiece to be processed; The double-axis grinding disc assembly is connected to the top of the other end of the bottom support member by sliding along the Y direction in the horizontal plane; the double-axis grinding disc assembly includes two grinding disc components arranged side by side along the Y direction, and the grinding disc components include a rotatable polishing disc; the polishing disc and the support disc are arranged face to face; the height of the polishing disc and the support disc are flush; A sealed chamber is arranged on the top of the bottom support member; the polishing plate and the support plate are arranged in the sealed chamber; A cooling circulation system connected to the sealed chamber and used for supplying polishing liquid to the support plate and the polishing plate; Among them, the workpiece rotary support assembly slides toward the dual-axis grinding disc assembly to clamp the workpiece to be processed; the polishing disc and the support disc respectively rotate in a plane perpendicular to the horizontal plane to process the workpiece to be processed.

[0010] In one embodiment of the present invention, the workpiece rotary support assembly also includes a first rotary shaft rotatably connected to the bottom support member; the first rotary shaft is coaxially connected to the support plate, a first hollow structure is provided in the first rotary shaft, a first through hole connected to the first hollow structure is provided on the support plate, and the first through hole is connected to the mounting groove; the cooling circulation system supplies polishing liquid to the surface of the support plate from the first hollow structure and the first through hole in turn.

[0011] In one embodiment of the present invention, the grinding wheel component also includes a second rotating shaft rotatably connected to the bottom support member; the second rotating shaft is coaxially connected to the polishing wheel; a second hollow structure is provided in the second rotating shaft, and a second through hole connected to the second hollow structure is provided on the polishing wheel; the cooling circulation system supplies polishing liquid to the surface of the polishing wheel from the second hollow structure and the second through hole in turn.

[0012] In one embodiment of the present invention, the workpiece rotary support assembly also includes a first rotary shaft rotatably connected to the bottom support member; the first rotary shaft is coaxially connected to the support disk, a first hollow structure is provided in the first rotary shaft, a first through hole connected to the first hollow structure is provided on the support disk, and the first through hole is connected to the mounting groove; the cooling circulation system sequentially supplies polishing liquid from the first hollow structure and the first through hole to the surface of the support disk. The grinding disk component also includes a second rotary shaft rotatably connected to the bottom support member; the second rotary shaft is coaxially connected to the polishing disk; a second hollow structure is provided in the second rotary shaft, and a second through hole connected to the second hollow structure is provided on the polishing disk; the cooling circulation system sequentially supplies polishing liquid from the second hollow structure and the second through hole to the surface of the polishing disk.

[0013] In one embodiment of the present invention, when the support plate is provided with a first through hole, a plurality of crisscrossing guide grooves are provided on a surface of the mounting groove parallel to the plate surface of the support plate; and the guide grooves are connected to the first through hole.

[0014] In one embodiment of the present invention, when the second through hole is provided on the polishing disk: a guide groove is also provided on the disk surface of the polishing disk, and the guide groove is communicated with the polishing disk.

[0015] In one embodiment of the present invention, when a first through hole is provided on the support plate: a plurality of criss-crossing guide grooves are provided on the surface of the mounting groove parallel to the disk surface of the support plate; the guide grooves are connected to the first through hole; when a second through hole is provided on the polishing plate: guide grooves are also provided on the disk surface of the polishing plate, and the guide grooves are connected to the polishing plate.

[0016] In one embodiment of the present invention, the present application also includes a movable vacuum flip loading and unloading bracket; the sealed cabin is provided with an openable and closable side door; the vacuum flip loading and unloading bracket enters and exits the sealed cabin from the side door, and is used to load and unload the workpiece to be processed onto the support plate.

[0017] In one embodiment of the present invention, the vacuum flip loading and unloading bracket includes a frame, a moving component, a vacuum device, a flip frame and a plurality of suction cups; the moving component is arranged at the bottom of the frame to drive the frame to move; the vacuum device is arranged on the top of the frame; the height of the flip frame is adjustable; the flip frame is rotatably connected to the frame, and the flip frame rotates in a vertical plane; a plurality of suction cup arrays are arranged on the flip frame, and the suction cups are connected to the vacuum device.

[0018] In one embodiment of the present invention, the vacuum flip loading and unloading bracket also includes a rotating shaft, an outer sleeve and a locking nut; the rotating shaft is rotatably connected to the frame through the outer sleeve, and a threaded hole is provided on the rotating shaft; an arc groove is provided on the end face of the outer sleeve, and the arc groove is concentric with the rotating shaft; the locking nut passes through the arc groove and is connected to the threaded hole.

[0019] In one embodiment of the present invention, the workpiece rotary support assembly further comprises a pressure sensor for monitoring the pressure exerted on the workpiece to be processed when the polishing disc and the support disc clamp the workpiece to be processed.

[0020] In one embodiment of the present invention, the support plate and the polishing plate are immersed in the polishing liquid in the sealed chamber, and the immersion depth is 100-300 mm.

[0021] In one embodiment of the present invention, the cooling circulation system includes a water tank, a mixer, a cooler and a liquid pump; the water tank is connected to a sealed cabin; the mixer, the cooler and the liquid pump are all arranged in the water tank, and the mixer is located in the middle part of the water tank, the cooler is located at one end of the water tank close to the sealed cabin, and the liquid pump is located at one end of the water tank away from the sealed cabin; the liquid pump is connected to the sealed cabin through a pipeline.

[0022] In one embodiment of the present invention, the grinding disc component also includes a motor, a ball screw and a screw nut; the motor is connected to the top of the bottom support member, the output shaft of the motor is connected to the ball screw, the screw nut cooperates with the ball screw, and the screw nut is connected to the bottom of the dual-axis grinding disc assembly.

[0023] The above technical solution of the present invention has the following advantages compared with the prior art: 1. The polishing disc and the supporting disc of the present invention are arranged vertically, so that the polishing surface of the workpiece to be processed is always perpendicular to the horizontal plane, thereby solving the deformation problem caused by the gravity of the quartz sheet (workpiece to be processed) itself, effectively improving the processing accuracy of the polishing plane and improving the yield rate.

[0024] 2. During the polishing process using this application, the cooling circulation system supplies polishing liquid (coolant) to the support plate and the polishing plate, so that the support plate and the polishing plate are always in a fully cooled state, effectively reducing local thermal deformation during the processing process and avoiding changes in flatness after the plate is removed; ensuring the stability and accuracy of the workpiece to be processed.

[0025] 3. The present application clamps the workpiece by the rotational friction between the two polishing discs and the support disc. It does not require the use of hard bonding or tight clamping methods, solves the deformation problem caused by clamping, reduces the deformation of the quartz sheet in the thickness direction, effectively improves the polishing plane accuracy, and reduces the probability of material fragmentation.

[0026] 4. The present application is provided with two polishing discs, which effectively and evenly polish the surface of the workpiece to be processed by reciprocating the two polishing discs in the Y direction during the polishing process. The situation where a single large-sized polishing disc is needed is avoided, the diameter of the polishing disc is reduced by 50%, and the production difficulty and cost are greatly reduced. In addition, due to the reduced diameter of the polishing disc, the working surface of the polishing disc is perpendicular to the horizontal plane, which reduces the need to resist gravity deformation, so that the thickness of the polishing disc can be reduced by 48.3% to 72.5%, further reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 It is a structural schematic diagram of a large-size photomask quartz glass substrate polishing device in a preferred embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of the interior of a sealed chamber in a large-size photomask quartz glass substrate polishing device; Figure 3 yes Figure 1A schematic diagram of the structure of a sealed chamber and a cooling circulation system in a large-size photomask quartz glass substrate polishing device; Figure 4 yes Figure 1 A front view of a vacuum flip loading and unloading bracket in a large-size photomask quartz glass substrate polishing device; Figure 5 yes Figure 1 A side view of a vacuum flip loading and unloading bracket in a large-size photomask quartz glass substrate polishing device; Figure 6 yes Figure 1 A schematic diagram of the structure of a support plate in a large-size photomask quartz glass substrate polishing device; Figure 7 yes Figure 1 A cross-sectional view of a support plate in a large-size photomask quartz glass substrate polishing device; Description of the accompanying drawings in the specification: 100, bottom support member; 200, workpiece rotary support assembly; 210, first rotary shaft; 211, first hollow structure; 220, first rotary power unit; 221, spindle motor; 222, driving gear; 223, driven gear; 224, reducer; 230, support plate; 231, mounting groove; 232, first through hole; 233, guide groove; 240, first support unit; 241, first base; 242, first support seat; 250, positioning convex plate; 260, first sliding power unit; 270, first porous polyurethane substrate; 280, pressure sensor; 290, guide component; 300, double-axis grinding disc assembly; 310, second rotary shaft; 311, second through hole; 312, second hollow structure; 320, second rotary power unit; 330, polishing disc; 340, second support unit; 341, second base; 342, second support seat; 350, second sliding power unit; 360, second porous polyurethane substrate; 400, sealed cabin; 410, side door; 420, reflux port; 430, polishing liquid layer; 500, cooling circulation system; 510, water tank; 520, mixer; 530, cooler; 540, liquid pump; 550, pipeline; 551, control valve; 600. Workpiece to be processed; 700, vacuum flip loading and unloading bracket; 710, frame; 720, moving part; 730, vacuum device; 740, flip frame; 750, suction cup; 760, lifting part; 761, gear; 762, rack; 763, rocker; 764, linear guide; 770, rotating power unit; 771, rotating shaft; 772, outer sleeve; 7721, arc groove; 7722, flange; 773, locking nut; 774, handle; 780, air pipe. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0029] Some comparative embodiments have the following problems: ① Since the quartz sheet is relatively thin and has a large area, it often warps and deforms due to gravity during processing. This deformation has a great impact on the processing accuracy and may even cause the processed pieces to be scrapped, seriously affecting the yield of the polishing process; ② During the polishing process, the quartz sheet and the clamping tooling produce slight deformations due to clamping force, heat, etc. This deformation disappears after the lower plate of the quartz sheet cools down, resulting in changes in the accuracy of the quartz sheet after the lower plate is removed, affecting the accuracy of the finished product; ③ The polishing disc base of the traditional polishing method is generally made of a whole piece of marble, and its radius is required to be no less than the diagonal diameter of the quartz sheet. The diameter of the polishing disc is too large, and the production and processing difficulties are extremely difficult, and the cost is high.

[0030] Reference Figure 1 to Figure 7 As shown, an embodiment of the present invention provides a large-size photomask quartz glass substrate polishing device, comprising: The bottom support member 100 serves as the main load-bearing part; The workpiece rotary support assembly 200 is connected to the top of one end of the bottom support member 100 by sliding along the X direction in the horizontal plane (XY plane); the workpiece rotary support assembly 200 includes a first rotary shaft 210, a first rotary power unit 220 and a rotatable support plate 230; one end of the first rotary shaft 210 is connected to the first rotary power unit 220, and the other end is connected to the support plate 230; the support plate 230 is provided with a mounting groove 231 on the plate surface for mounting the workpiece 600 to be processed; in some embodiments, the size of the mounting groove 231 is 1-2 mm larger than the corresponding size of the workpiece 600 to be processed, and the depth of the mounting groove 231 is 1 / 2 of the thickness of the workpiece. The plane where the mounting groove 231 contacts the workpiece 600 to be processed has a plane accuracy requirement of 000 level, and a rotary runout better than 0.005 mm.

[0031] The double-axis grinding disc assembly 300 is slidably connected to the top of the other end of the bottom support member 100 along the Y direction in the horizontal plane. The double-axis grinding disc assembly 300 includes two grinding disc components arranged side by side along the Y direction, and the grinding disc components include a second rotary shaft 310, a second rotary power unit 320, and a rotatable polishing disc 330; one end of the second rotary shaft 310 is connected to the second rotary power unit 320, and the other end is connected to the polishing disc 330; the polishing disc 330 is arranged face to face with the support disc 230; the axis of the polishing disc 330 is flush with the axis of the support disc 230; the diameter of the polishing disc 330 is close to the maximum diameter of the workpiece 600 to be processed.

[0032] The sealed chamber 400 is disposed on the top of the bottom support member 100; the sealed chamber 400 is connected to the bottom support member 100 by screws. Holes are respectively opened on both sides of the sealed chamber 400 along the X direction, and the first rotating shaft 210 and the second rotating shaft 310 pass through the holes through the sleeves respectively. The polishing plate 330 and the supporting plate 230 are disposed in the sealed chamber 400; A cooling circulation system 500 connected to the sealed chamber 400 and used to supply polishing liquid to the support plate 230 and the polishing plate 330; The workpiece rotary support assembly 200 slides toward the dual-axis grinding disc assembly 300 to clamp the workpiece 600 to be processed; the polishing disc 330 and the support disc 230 respectively rotate in planes perpendicular to the horizontal plane to process the workpiece 600 to be processed.

[0033] The beneficial effects of this application are as follows: 1. The polishing plate 330 and the support plate 230 of the present invention are arranged vertically, so that the polishing surface of the workpiece 600 to be processed is always perpendicular to the horizontal plane, thereby solving the deformation problem caused by the gravity of the quartz plate (the workpiece 600 to be processed) itself, effectively improving the processing accuracy of the polishing plane and improving the yield rate.

[0034] 2. During the polishing process using the present application, the cooling circulation system 500 supplies polishing liquid (coolant) to the support plate 230 and the polishing plate 330, so that the support plate 230 and the polishing plate 330 are always in a fully cooled state, effectively reducing local thermal deformation during the processing process and avoiding changes in flatness after the plate is removed; ensuring the stability and accuracy of the workpiece 600 to be processed.

[0035] 3. The two polishing discs 330 of the present application use the rotational friction with the support disc 230 to clamp the workpiece, which does not require the use of hard bonding or tight clamping methods, solves the deformation problem caused by clamping, reduces the deformation of the quartz sheet in the thickness direction, effectively improves the polishing plane accuracy, and reduces the probability of material fragmentation.

[0036] 4. The present application is provided with two polishing discs 330, and the two polishing discs 330 reciprocate along the Y direction during the polishing process to effectively and evenly polish the surface of the workpiece 600 to be processed. The situation where a single large-sized polishing disc 330 needs to be used is avoided, and the diameter of the polishing disc 330 is reduced by 50%, which greatly reduces the production difficulty and cost. In addition, due to the reduction in the diameter of the polishing disc 330, the working surface of the polishing disc 330 is perpendicular to the horizontal plane, which reduces the need to resist gravity deformation, so that the thickness of the polishing disc 330 can be reduced by 48.3% to 72.5%, further reducing the production cost.

[0037] It can be seen that the present application solves the problems of gravity deformation and heat deformation generated during polishing; improves the overall quality and yield rate of the mask substrate; reduces the requirements for the disk size of the polishing equipment, and reduces costs.

[0038] In some embodiments, the polishing plate 330 is disposed perpendicular to the horizontal plane, and the verticality of the polishing plate 330 is 90°±1°. The supporting plate 230 is disposed perpendicular to the horizontal plane, and the verticality of the supporting plate 230 is 90°±1°.

[0039] In some embodiments, the diameter D1 of the support plate 230 = the maximum diameter D2 of the workpiece 600 to be processed + D2 / 20, and the thickness H1 of the support plate 230 is 1 / 30 to 1 / 20 of the diameter D1.

[0040] In some embodiments, the diameter D3 of the polishing disc 330 = the maximum diameter D2 of the workpiece 600 to be processed + D2 / 20, and the thickness H3 of the polishing disc 330 is 1 / 30 to 1 / 20 of its diameter D3. The plane accuracy of the surface of the polishing disc 330 in contact with the workpiece 600 to be processed is required to be 000 level, and the rotation runout is better than 0.005mm.

[0041] In some embodiments, the support plate 230 and the polishing plate 330 are made of the same material, and the main material of both is marble. Specifically, they are made of fine-grained, densely structured gabbro, diabase, granite (biotite should be less than 5%, elastic modulus should be greater than 0.6x10-4kg / cm2, water absorption should be less than 0.25%) and other materials, and the hardness of the working surface should be greater than 70Hs.

[0042] In some embodiments, the workpiece rotary support assembly 200 further includes a first support portion 240, which includes a first base 241 and at least one first support seat 242. The first base 241 is horizontally arranged, and the first base 241 is slidably connected to the bottom support member 100. The first support seat 242 is vertically arranged and connected to the top of the first base 241; the first rotary shaft 210 is rotatably connected to the top of the first support seat 242 through a bearing. In some embodiments, the dual-axis grinding disc assembly 300 further includes a second support portion 340. The structure of the second support portion 340 is the same as that of the first support portion 240. That is, the second support portion 340 includes a second base 341 and at least one second support seat 342. The second base 341 is horizontally arranged, and the second base 341 is slidably connected to the bottom support member 100; the second support seat 342 is vertically arranged and connected to the top of the second base 341. The second rotary shaft 310 is rotatably connected to the top of the second support seat 342 through a bearing. Specifically, the first support portion 240 provides support for the first rotary power unit 220 and the first rotary shaft 210, etc. Similarly, the second support portion 340 provides support for the second rotary power unit 320 and the second rotary shaft 310, etc.

[0043] In some embodiments, the workpiece rotary support assembly 200 further includes a positioning convex plate 250; the positioning convex plate 250 is concentric with the support disc 230; the positioning convex plate 250 is fixed to the back side of the support disc 230 (i.e., the side of the support disc 230 facing the first rotary shaft 210) by screws. The positioning convex plate 250 is connected and fixed to the first rotary shaft 210 by a sealing ring and screws. In addition, the grinding disc component also includes a positioning convex plate, and the connection structure between the positioning convex plate and the grinding disc component is the same as that of the workpiece rotary support assembly 200, which will not be repeated here.

[0044] Furthermore, the workpiece rotary support assembly 200 further includes a first sliding power unit 260; the first sliding power unit 260 is connected to the bottom support member 100, and the output shaft of the first sliding power unit 260 is connected to the first base 241 of the workpiece rotary support assembly 200. In some embodiments, the first sliding power unit 260 is a cylinder. Specifically, the workpiece rotary support assembly 200 can be controlled by the cylinder to reciprocate along the X direction on the bottom support member 100, with a simple structure, stable and reliable operation, and low cost.

[0045] Furthermore, the grinding disc component further includes a second sliding power unit 350, which includes a motor, a ball screw and a screw nut; the motor is connected to the top of the bottom support 100, the output shaft of the motor is connected to the ball screw, the screw nut cooperates with the ball screw, and the screw nut is connected to the bottom of the second base 341 of the dual-axis grinding disc assembly 300. The motor drives the ball screw to rotate, thereby driving the screw nut and the second base 341 of the dual-axis grinding disc assembly 300 to slide synchronously on the bottom support 100.

[0046] Furthermore, the workpiece rotary support assembly 200 also includes a guide component 290, and the guide component 290 includes a linear guide rail and a slider; the linear guide rail is connected to the top of the bottom support 100, and the slider is connected to the bottom of the first base 241 of the workpiece rotary support assembly 200, and the slider cooperates with the linear guide rail. In some embodiments, the grinding disc component also includes a guide component, and the structure of its guide component is the same as that of the workpiece rotary support assembly 200. It will not be repeated here. Specifically, the guide component can provide a guiding effect, so that the workpiece rotary support assembly 200 and the dual-axis grinding disc assembly 300 can slide more smoothly and more steadily on the bottom support 100.

[0047] Further, the first rotary power unit 220 includes a spindle motor 221, a driving gear 222 and a driven gear 223; the spindle motor 221 is connected to the first base 241, the output shaft of the spindle motor 221 is connected to the driving gear 222, the driven gear 223 is meshed with the driving gear 222, and the driven gear 223 is coaxially connected to the first rotary shaft 210. In some embodiments, the first rotary power unit 220 also includes a reducer 224, the reducer 224 is connected to the output shaft of the spindle motor 221, and the output shaft of the reducer 224 is connected to the driving gear 222. In some other embodiments, the spindle motor 221 is connected to the first rotary shaft 210 through a driving pulley and a driven pulley, which is a prior art and will not be repeated here. Specifically, the spindle motor 221 provides rotary power, and then transmits the rotary power to the first rotary shaft 210 through the driving gear 222 and the driven gear 223, thereby driving the first rotary shaft 210 to rotate forward or reverse at a process speed. Its structure is stable and reliable, and its cost is low. In some embodiments, the structure of the second rotary power unit 320 is the same as that of the first rotary power unit 220, and will not be repeated here.

[0048] Further, the first rotating shaft 210 is a hollow shaft, a first hollow structure 211 is provided in the first rotating shaft 210, a first through hole 232 is provided on the support plate 230 and communicates with the first hollow structure 211, and the first through hole 232 is communicated with the mounting groove 231; the cooling circulation system 500 supplies polishing liquid to the disk surface of the support plate 230 from the first hollow structure 211 and the first through hole 232. The second rotating shaft 310 is a hollow shaft, a second hollow structure 312 is provided in the second rotating shaft; a second through hole 311 is provided on the polishing plate 330 and communicates with the second hollow structure 312; the cooling circulation system 500 supplies polishing liquid to the disk surface of the polishing plate 330 from the second hollow structure 312 and the second through hole 311. In some embodiments, the aperture of the first through hole 232 is not less than the inner diameter of the first hollow structure 211. Similarly, the aperture of the second through hole 311 is not less than the inner diameter of the second hollow structure 312.

[0049] Specifically, in this embodiment, the polishing liquid can be supplied to the center of the disk surface of the support disk 230 and the polishing disk 330 through the first hollow structure 211 and the first through hole 232 in the first rotating shaft 210, and the second hollow structure 312 and the second through hole 311 in the second rotating shaft 310, respectively, so that the distribution uniformity of the polishing liquid on the polishing surface can be improved. In addition, the polishing liquid flows along the disk surface to the bottom of the sealed cabin 400 to form the polishing liquid 430. During the polishing process, the polishing liquid gradually overflows the bottom of the cabin body of the sealed cabin 400, and the bottom of the support disk 230 and the polishing disk 330 can be immersed in the polishing liquid layer 430. Parts of the bottom of the polishing disk 330 and the support disk 230 will be submerged below the liquid surface, so that the support disk 230 and the polishing disk 330 are further cooled and moistened. In addition, during the rotational polishing process of the support plate 230 and the polishing plate 330, the polishing liquid is stirred, thereby continuously lubricating the surfaces of the support plate 230 and the polishing plate 330, improving the sedimentation problem of the polishing liquid and optimizing the concentration distribution of the polishing liquid. It can be seen that this embodiment further improves the polishing effect and accuracy.

[0050] Further, in the case where the first through hole 232 is provided on the support disk 230: a plurality of crisscrossing guide grooves 233 are provided on the surface of the mounting groove 231 parallel to the disk surface of the support disk 230; the guide grooves 233 are connected to the first through hole 232. In the case where the second through hole 311 is provided on the polishing disk 330: a guide groove is also provided on the disk surface of the polishing disk 330, and the guide groove is connected to the polishing disk 330. In some embodiments, the depth of the guide groove 233 on the support disk 230 is 3 to 5 mm and the width is 3 to 5 mm. The depth of the guide groove on the polishing disk 330 is 0.5 mm and the width is 1 mm. Specifically, the guide groove 233 provided in this embodiment enables the polishing liquid to be quickly and evenly distributed in the mounting groove 231 and on the disk surface of the polishing disk 330, thereby further evenly cooling the support disk 230 and the polishing disk 330.

[0051] Further, a first porous polyurethane substrate 270 is pasted on the surface of the support disc 230 in contact with the workpiece 600 to be processed, and a porous polyurethane substrate is also pasted on the side surface of the mounting groove 231. In some embodiments, the thickness of the first porous polyurethane substrate 270 is 1 to 0.5 mm. A second porous polyurethane substrate 360 ​​is also pasted on the surface of the polishing disc 330 in contact with the workpiece 600 to be processed. In some embodiments, the thickness of the second porous polyurethane substrate 360 ​​is 1 to 1.5 mm. The first porous polyurethane substrate 270 and the second porous polyurethane substrate 360 ​​have the same function. The porous polyurethane substrate can play a role in assisting polishing. Since the surface of the porous polyurethane substrate is a porous structure, the time for the particles in the polishing liquid to act on the polishing surface during the polishing process can be extended, thereby further improving the polishing efficiency. In addition, since the material of the support disc 230 is marble, a porous polyurethane substrate is provided, which can play a buffering role.

[0052] Further, the present application also includes a movable vacuum flip loading and unloading bracket 700; the sealed cabin 400 is provided with a side door 410 that can be opened and closed; there can be two side doors 410, and the two side doors 410 are arranged on both sides of the sealed cabin 400 along the Y axis. The side door 410 can be opened and closed 180 degrees. For example, the side door 410 opens upward. The vacuum flip loading and unloading bracket 700 enters and exits the sealed cabin 400 from the side door 410, and is used to load and unload the workpiece 600 to be processed to the support plate 230. In some embodiments, the vacuum flip loading and unloading bracket 700 includes a frame 710, a moving part 720, a vacuum device 730, a flip frame 740 and a plurality of suction cups 750. The moving part 720 is arranged at the bottom of the frame 710, and is used to drive the frame 710 to move; in some embodiments, the moving part 720 can be a plurality of universal wheels. The vacuum device 730 is arranged at the top of the frame 710, and the negative pressure is required to be not less than -0.99kp. The height of the flip frame 740 is adjustable; the length of the flip frame 740 needs to ensure that it can penetrate deep into the sealed cabin 400 and enable the workpiece 600 to be processed adsorbed on the suction cup 750 to dock into the mounting groove 231. The flip frame 740 is rotatably connected to the frame 710, and the flip frame 740 rotates in a vertical plane. There are plural suction cups 750, and a plurality of suction cups 750 are arranged in an array on the flip frame 740. The suction cups 750 are connected to the vacuum device 730 through an air pipe 780. Specifically, the present embodiment realizes the loading and unloading of the workpiece 600 to be processed through the vacuum flip loading and unloading bracket 700, which is convenient and quick, and will not cause damage to the workpiece 600 to be processed or cause its deformation to affect the processing accuracy.

[0053] In some embodiments, the vacuum flip loading and unloading support 700 is further provided with an L-shaped table (not shown in the figure) for placing the workpiece 600 to be processed.

[0054] Further, the vacuum flip loading and unloading bracket 700 also includes a lifting component 760, and the lifting component 760 includes a gear 761 and a rack 762 meshing with the gear 761. The gear 761 is rotatably connected to the frame 710, and the rack 762 is vertically arranged on the flip frame 740. In one possible embodiment, a rocker 763 is provided on the gear 761. The gear 761 is rotated by manually rotating the rocker 763, thereby driving the flip frame 740 to rise and fall. In another possible embodiment, the gear 761 is connected to a motor, and the motor drives the gear 761 to rotate. Specifically, the structure of this embodiment is stable and reliable.

[0055] Furthermore, the lifting component 760 also includes a linear guide rail 764, which is connected between the frame 710 and the flip frame 740 to provide a guiding function.

[0056] Furthermore, the vacuum flip loading and unloading bracket 700 also includes a rotating power unit 770; the rotating power unit 770 includes a rotating shaft 771, an outer sleeve 772 and a locking nut 773. The rotating shaft 771 is rotatably connected to the frame 710 through the outer sleeve 772, and a threaded hole is provided on the rotating shaft 771; the end surface of the outer sleeve 772 is provided with an arc groove 7721, and the arc groove 7721 is concentric with the rotating shaft 771. In some embodiments, the end surface of the outer sleeve 772 is provided with an inward flange 7722 against the end of the rotating shaft 771, and the arc groove 7721 is provided on the flange 7722. The locking nut 773 passes through the arc groove 7721 and is connected to the threaded hole. In some possible embodiments, a handle 774 is provided on the rotating shaft 771, so that the rotating shaft 771 is driven to rotate by the handle 774, which has a simple structure and low cost. In some other possible implementations, the rotating shaft 771 is connected to a power component (e.g., a motor), and the power component drives the rotating shaft 771 to rotate to achieve automatic control. Specifically, in this embodiment, when the rotating shaft 771 needs to be rotated, the locking nut 773 is loosened, and then the rotating shaft 771 is rotated to drive the flip frame 740 to rotate. When it rotates to the target position, the locking nut 773 is tightened to fix the rotating shaft 771 to prevent it from rotating. It can be seen that in this embodiment, the flip frame 740 is driven to rotate synchronously by the rotation of the rotating shaft 771, and the structure is simple and the operation is convenient and fast.

[0057] Furthermore, the workpiece rotary support assembly 200 further includes a pressure sensor 280 for monitoring the pressure on the workpiece 600 to be processed when the polishing disc 330 and the support disc 230 clamp the workpiece 600 to be processed. In some possible implementations, the workpiece rotary support assembly 200 reciprocates on the bottom support member 100 through a cylinder. The pressure sensor 280 dynamically monitors and controls the pressurization pressure of the cylinder, thereby being able to monitor the pressure on the workpiece 600 to be processed. Specifically, in this embodiment, the pressure on the workpiece 600 to be processed is monitored through the pressure sensor 280, thereby ensuring that when the workpiece 600 to be processed is clamped, damage to the workpiece 600 to be processed due to excessive clamping force is avoided.

[0058] Furthermore, the support plate 230 and the polishing plate 330 are immersed in the polishing liquid in the sealed chamber 400, and the immersion depth is 100-300 mm. That is, the height of the reflux port 420 (described below) is 100-300 mm higher than the lowest end of the support plate 230 and the polishing plate 330. Specifically, this embodiment can ensure the cooling effect without affecting the rotation of the support plate 230 and the polishing plate 330 (because, if the immersion depth is too large, it will cause too much resistance to the rotation of the support plate 230 and the polishing plate 330, and if the immersion depth is too small, the cooling effect is not good).

[0059] Further, the cooling circulation system 500 includes a water tank 510, a mixer 520, a cooler 530 and a liquid pump 540. The water tank 510 is in communication with the sealed cabin 400; the mixer 520, the cooler 530 and the liquid pump 540 are all arranged in the water tank 510. The mixer 520 is located in the middle of the water tank 510, the cooler 530 is located at one end of the water tank 510 close to the sealed cabin 400, and the liquid pump 540 is arranged at one end of the water tank 510 away from the sealed cabin 400. The liquid pump 540 is in communication with the sealed cabin 400 through a pipeline 550. In some embodiments, an opening is provided at the top of the water tank 510, and correspondingly, a reflux port 420 is provided at the bottom of the sealed cabin 400, and a plate member tilted downward from the inside of the sealed cabin 400 to the outside thereof is set at the reflux port 420, and the free end of the plate member is located directly above the opening. In some other embodiments, the reflux port 420 is connected to the opening through a pipe 550. Specifically, in this embodiment, the higher temperature polishing liquid in the sealed chamber 400 is refluxed to the water tank 510, and then the lower temperature polishing liquid in the water tank 510 is stirred and mixed with the refluxed polishing liquid by the mixer 520, so that the temperature of the refluxed polishing liquid is reduced, and finally the cooled polishing liquid is transported to the support plate 230 and the polishing plate 330 by the liquid pump 540. It can be seen that the cooling circulation system 500 can circulate the polishing liquid to the sealed chamber 400 and realize polishing cooling.

[0060] It should be noted that, when the first rotating shaft 210 and the second rotating shaft 310 are hollow shafts, the liquid pump 540 is connected to the first rotating shaft 210 and the second rotating shaft 310 through pipelines (e.g., hoses). A corresponding control valve 551 is provided on the pipeline, so that the control valve 551 is used to adjust whether or not liquid is supplied to the support plate 230 and the polishing plate 330 and the flow rate of the supplied liquid.

[0061] The process of polishing using this application is as follows: 1. Ensure that the water tank 510 of the cooling circulation system 500 is filled with polishing liquid, the main component of which is cerium oxide, with a solid content of 15% to 30%. Turn on the cooler 530 and the mixer 520 of the cooling circulation system 500, and turn on the cylinder to control the workpiece rotary support assembly 200 to move on the bottom support 100, so that the workpiece rotary support assembly 200 is away from the dual-axis grinding disc assembly 300; 2. The total flow rate of the cooling polishing liquid is 80~220L / min, and the temperature of the polishing liquid is set to 23±0.5℃; 3. Place the quartz plate (workpiece to be processed 600) after grinding and cleaning vertically on the L-shaped table, move the vacuum flip loading and unloading bracket 700 and adjust the height of the flip frame 740 to ensure that the suction cup 750 is tightly attached to the surface of the quartz plate; 4. Open the vacuum device 730, raise the flip frame 740 to raise the quartz plate, open the side door 410 of the sealed chamber 400, move the vacuum flip loading and unloading bracket 700 into the sealed chamber 400, and place the quartz plate in the mounting groove 231 of the workpiece rotary support assembly 200; 5. Use a plastic sheet to hold the quartz plate against the plate to prevent it from falling. Turn off the vacuum device 730 to release the suction cup 750, and then remove the vacuum flip loading and unloading bracket 700; 6. Open the control valve 551 of the coolant (polishing liquid) of the dual-axis grinding disc assembly 300, so that the coolant (polishing liquid) flows out from the second through holes 311 of the two polishing discs 330 and covers the entire polishing surface. Turn on the cylinder to control the workpiece rotary support assembly 200 to move on the bottom support 100, so that the workpiece rotary support assembly 200 is close to the dual-axis grinding disc assembly 300. When the distance between the two is close, remove the plastic sheet until the workpiece rotary support assembly 200 and the dual-axis grinding disc assembly 300 are in close contact with each other to clamp the workpiece 600 to be processed. Then close the side door 410 of the sealed cabin 400. At this time, the pressure of the cylinder can be set to 10~50kg, and mark the position of the workpiece rotary support assembly 200 on the guide rail of the bottom support 100 at this time; 7. Open the control valve 551 of the workpiece rotary support assembly 200, so that the coolant flows out from the first through hole 232 of the support plate 230, and then the mounting groove 231 covers the entire plate surface, so that the entire workpiece 600 to be processed is evenly cooled. Control the support plate 230 to rotate, and set the speed to 5~8rpm. Control the polishing plate 330 to rotate, and set the speed to 5~8rpm. The direction of the polishing plate 330 is opposite to that of the support plate 230. Control the dual-axis grinding plate assembly 300 to reciprocate along the Y direction (i.e., the front and back direction), and the distance of the front and back movement is greater than half of the maximum size of the workpiece 600 to be processed (the diagonal for a square workpiece and the diameter for a circular workpiece), and the moving speed can be set to 100~300mm / min; 8. After all the movements start, adjust the cylinder pressure of the workpiece rotary support assembly 200 to 60-100 kg, and adjust the rotation speed of the workpiece rotary support assembly 200 and the discs of the dual-axis grinding disc assembly 300 (i.e., the support disc 230 and the polishing disc 330) to 15-20 rpm. Observe the position change of the workpiece rotary support assembly 200 on the guide rail of the bottom support member 100, so as to determine the polished removal thickness; 9. When the single-sided polishing removal thickness is close to the target, adjust the pressure of the cylinder of the workpiece rotary support assembly 200 to 10-20kg, and adjust the rotation speed of the support plate 230 and the polishing plate 330 to 5-8rpm until the removal thickness reaches the target. Control the dual-axis grinding disc assembly 300 to move and stop at the center of the distance between the two polishing discs 330 to align with the center of the workpiece 600 to be processed (for easy material removal), then stop the rotation of the support plate 230 and the polishing disc 330, and close the control valve 551 of the workpiece rotary support assembly 200 and the dual-axis grinding disc assembly 300; 10. Open the two side doors 410 of the sealed chamber 400, and use a plastic sheet to hold the quartz plate (the workpiece to be processed 600) against it to prevent it from falling. At the same time, start the cylinder to make the workpiece rotary support assembly 200 away from the dual-axis grinding disc assembly 300; 11. Move the vacuum flip loading and unloading bracket 700 into the sealed chamber 400, and make the suction cup 750 completely fit on the quartz plate, open the vacuum device 730 to make the suction cup 750 suck the quartz plate, and then move the vacuum flip loading and unloading bracket 700 to take out the quartz plate and place it on the L-shaped table. Close the vacuum device 730, and flip the flip frame 740 of the vacuum flip loading and unloading bracket 700 180°; 12. Wipe the polished surface of the quartz plate clean and clean the surface of the support plate 230; 13. Use the vacuum flip loading and unloading bracket 700 to absorb the polished surface of the quartz plate, then flip the flip frame 740 of the vacuum flip loading and unloading bracket 700 and the quartz plate 180 degrees, and repeat the above steps 3 to 12; 14. Clean and inspect the quartz wafers that have been polished on both sides.

[0062] In some embodiments, after polishing using the present invention, the flatness of the polished surface is generally better than 20 μm, and can reach 5 to 15 μm on average.

[0063] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A large-size photomask quartz glass substrate polishing device, characterized in that: include: Bottom support member; A workpiece rotary support assembly is slidably connected to the top of one end of the bottom support member in the horizontal plane along the X direction; the workpiece rotary support assembly includes a rotatable support plate; the plate surface of the support plate is provided with a mounting groove for mounting the workpiece to be processed; A double-axis grinding disc assembly is slidably connected to the top of the other end of the bottom support member in the Y direction in a horizontal plane; the double-axis grinding disc assembly includes two grinding disc components arranged side by side in the Y direction, and the grinding disc components include a rotatable polishing disc; the polishing disc and the support disc are arranged face to face; the heights of the axes of the polishing disc and the support disc are flush; A sealed cabin is arranged on the top of the bottom support member; the polishing plate and the support plate are arranged in the sealed cabin; a cooling circulation system connected to the sealed chamber and used for supplying polishing liquid to the support plate and the polishing plate; Wherein, the workpiece rotary support assembly slides toward the dual-axis grinding disc assembly to clamp the workpiece to be processed; the polishing disc and the support disc respectively rotate in a plane perpendicular to the horizontal plane to process the workpiece to be processed.

2. The large-size photomask quartz glass substrate polishing device according to claim 1, characterized in that: The workpiece rotary support assembly also includes a first rotary shaft rotatably connected to the bottom support member; the first rotary shaft is coaxially connected to the support plate, a first hollow structure is provided in the first rotary shaft, a first through hole connected to the first hollow structure is provided on the support plate, and the first through hole is connected to the mounting groove; the cooling circulation system sequentially supplies polishing liquid from the first hollow structure and the first through hole to the disk surface of the support plate; And / or, the grinding wheel component also includes a second rotating shaft rotatably connected to the bottom support member; the second rotating shaft is coaxially connected to the polishing wheel; a second hollow structure is provided in the second rotating shaft, and a second through hole connected to the second hollow structure is provided on the polishing wheel; the cooling circulation system supplies polishing liquid to the surface of the polishing wheel from the second hollow structure and the second through hole in sequence.

3. The large-size photomask quartz glass substrate polishing device according to claim 2, characterized in that: In the case where the support plate is provided with a first through hole: a plurality of crisscrossing guide grooves are provided on a surface of the mounting groove parallel to the plate surface of the support plate; the guide grooves are connected to the first through hole; And / or, in the case where the second through hole is provided on the polishing disk: a guide groove is also provided on the disk surface of the polishing disk, and the guide groove is communicated with the polishing disk.

4. The large-size photomask quartz glass substrate polishing device according to claim 1, characterized in that: It also includes a movable vacuum flip loading and unloading bracket; the sealed cabin is provided with an openable and closable side door; the vacuum flip loading and unloading bracket enters and exits the sealed cabin from the side door, and is used for loading and unloading the workpiece to be processed onto the support plate.

5. The large-size photomask quartz glass substrate polishing device according to claim 4, characterized in that: The vacuum flip loading and unloading bracket comprises a frame, a moving part, a vacuum device, a flip frame and a plurality of suction cups; the moving part is arranged at the bottom of the frame to drive the frame to move; the vacuum device is arranged at the top of the frame; the height of the flip frame is adjustable; The flip frame is rotatably connected to the frame, and the flip frame rotates in a vertical plane; a plurality of suction cup arrays are arranged on the flip frame, and the suction cups are connected to the vacuum device.

6. The large-size photomask quartz glass substrate polishing device according to claim 5, characterized in that: The vacuum flip loading and unloading bracket also includes a rotating shaft, an outer sleeve and a locking nut; the rotating shaft is rotatably connected to the frame through the outer sleeve, and a threaded hole is provided on the rotating shaft; an arc groove is provided on the end surface of the outer sleeve, and the arc groove is concentric with the rotating shaft; the locking nut passes through the arc groove and is connected to the threaded hole.

7. The large-size photomask quartz glass substrate polishing device according to claim 1, characterized in that: The workpiece rotary support assembly further includes a pressure sensor for monitoring the pressure exerted on the workpiece to be processed when the polishing disc and the support disc clamp the workpiece to be processed.

8. The large-size photomask quartz glass substrate polishing device according to claim 1, characterized in that: The supporting plate and the polishing plate are immersed in the polishing liquid in the sealed chamber, and the immersion depth is 100-300 mm.

9. The large-size photomask quartz glass substrate polishing device according to claim 1, characterized in that: The cooling circulation system includes a water tank, a mixer, a cooler and a liquid pump; the water tank is connected to the sealed cabin; the mixer, the cooler and the liquid pump are all arranged in the water tank, and the mixer is located in the middle part of the water tank, the cooler is located at one end of the water tank close to the sealed cabin, and the liquid pump is arranged at one end of the water tank away from the sealed cabin; the liquid pump is connected to the sealed cabin through a pipeline.

10. The large-size photomask quartz glass substrate polishing device according to claim 1, characterized in that: The grinding disc component also includes a motor, a ball screw and a screw nut; the motor is connected to the top of the bottom support, the output shaft of the motor is connected to the ball screw, the screw nut cooperates with the ball screw, and the screw nut is connected to the bottom of the dual-axis grinding disc assembly.

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