Large-size photomask quartz glass substrate polishing device

Abstract

The utility model 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 utility model 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 rate of finished products are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of photomask preparation technology, especially to a large size photomask quartz glass substrate polishing device. BACKGROUND

[0002] The photomask in the microelectronic manufacturing process is also called mask, photomask, and lithography mask plate, which is a microelectronic manufacturing process pattern transfer tool or master plate, and is a carrier of pattern design and process technology intellectual property information. In the lithography process, the mask plate is a carrier of the designed pattern. Through lithography, the designed pattern on the mask plate is transferred to the photoresist, and then the pattern is etched on the substrate, so as to realize the transfer of the pattern to the silicon wafer, which is similar to the "film" of the traditional camera, and carries the core technical parameters of the electronic circuit.

[0003] Taking the thin film transistor liquid crystal display (TFT-LCD) manufacturing as an example, the exposure masking effect of the mask plate is used to expose and transfer the designed thin film transistor (TFT) array and color filter pattern to the glass substrate in sequence according to the film layer structure of the thin film transistor, and finally form a display device stacked by multiple film layers. Taking wafer manufacturing as an example, the manufacturing process needs to go through multiple exposure processes, and the exposure masking effect of the mask plate is used to form gate, source and drain, doping window, electrode contact hole and the like on the surface of the semiconductor wafer. The mask plate is an important component in the lithography process, and its performance has an important influence on the lithography.

[0004] Synthetic quartz glass is widely used in semiconductor, precision optics and other fields due to its excellent optical performance, heat shock resistance, extremely low thermal expansion coefficient and electrical conductivity. Synthetic quartz mask plate is a blank photomask substrate processed from synthetic quartz ingot, which has high chemical stability, high hardness, low thermal expansion coefficient, high transmittance (especially in the ultraviolet segment), and is often used as the substrate of IC, LSI large FPD high-precision device. At present, the planar processing of quartz glass is mainly through diamond grinding tool to grind a certain thickness, so as to have certain roughness, flatness, parallelism and the like, and then polished by polishing abrasive, and finally meet the requirements of finished product. The photomask quartz glass substrate is also processed by the same method.

[0005] In the processing of the photomask quartz glass substrate, the control of the polishing flatness is particularly important. For example, in the photolithography technology using an ArF laser source with a wavelength of 193 nm and in the photolithography technology based on the combination of the ArF laser source and the immersion technique, the quartz glass substrate used as the photomask needs to have good flatness. If the exposure surface is not flat during exposure, the displacement of the focal point on the silicon wafer will cause the pattern consistency to be poor, so that a fine pattern cannot be formed. Taking the G8 generation TFT-LCD photomask quartz glass substrate as an example, the diagonal size thereof is close to 1.9 m or more, and the thickness thereof is between 8 mm and 14 mm, and the flatness requirement thereof is not more than 40 μm. Due to the thin thickness and large area, the processing difficulty is extremely high.

[0006] The traditional processing method is to cut the quartz piece with a certain thickness from the synthetic quartz base whose shape has been milled and ground. The cutting flatness of the equipment for cutting large-size quartz pieces can only reach within 100 μm, and the cutting precision is limited. After cutting, the grinding process is needed. The grinding processing mode is that one surface is taken as the reference surface, and the other surface is ground, and the two surfaces are alternately ground. At this time, the flatness is often controlled within 80-90 μm. In the subsequent stage, the quartz piece is fixed on a horizontally placed radial rotating polishing disc by means of jig clamping or vacuum adsorption, and is ground with the aid of polishing abrasive. The radius of the polishing disc is required to be not less than the diagonal diameter of the quartz piece. This step requires that the flatness of the quartz piece be controlled within 40 μm, and usually within 20 μm. After polishing one surface, the quartz piece is turned over, and the other surface is polished until the requirement is met. Finally, the quartz piece is cleaned and coated through processes such as cleaning and coating.

[0007] The problems existing in the traditional polishing method are as follows: warping deformation is generated during processing, which seriously affects the yield of the polishing process; slight deformation is generated due to clamping stress and heating, which causes the accuracy of the quartz piece to change after the lower disc, and affects the accuracy of the finished product; the production and processing difficulty of the polishing disc is extremely great, and the cost is high. Practical new type content

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

[0009] To solve the above technical problems, the present application provides a large-size photomask quartz glass substrate polishing device, which comprises:

[0010] A bottom support member;

[0011] A workpiece rotating support assembly is connected to the top of one end of the bottom support member in the horizontal plane along the X direction. The workpiece rotating support assembly comprises a rotatable support disc. The disc surface of the support disc is provided with a mounting groove for mounting the workpiece to be processed.

[0012] A double-shaft grinding disc assembly is slidably connected to the top of the bottom support at the other end in the Y direction in the horizontal plane; the double-shaft grinding disc assembly comprises two grinding disc components arranged side by side in the Y direction, and the grinding disc components comprise rotatable polishing discs; the polishing discs are arranged face to face with the support disc; the polishing discs are flush with the support disc in height;

[0013] A sealed cabin is arranged at the top of the bottom support; the polishing discs and the support disc are arranged in the sealed cabin;

[0014] A cooling circulation system is connected to the sealed cabin and is used to supply polishing liquid to the support disc and the polishing disc;

[0015] The workpiece rotary support assembly slides towards the double-shaft grinding disc assembly to clamp the workpiece to be processed; the polishing disc and the support disc rotate in a plane perpendicular to the horizontal plane to process the workpiece to be processed.

[0016] In an embodiment of the utility model, the workpiece rotary support assembly further comprises a first rotary shaft rotatably connected to the bottom support; the first rotary shaft is coaxially connected to the support disc; the first rotary shaft is provided with a first hollow structure; the support disc is provided with a first through hole in communication with the first hollow structure; the first through hole is in communication with the mounting groove; the cooling circulation system supplies polishing liquid to the disc surface of the support disc through the first hollow structure and the first through hole in sequence.

[0017] In an embodiment of the utility model, the grinding disc component further comprises a second rotary shaft rotatably connected to the bottom support; the second rotary shaft is coaxially connected to the polishing disc; the second rotary shaft is provided with a second hollow structure; the polishing disc is provided with a second through hole in communication with the second hollow structure; the cooling circulation system supplies polishing liquid to the disc surface of the polishing disc through the second hollow structure and the second through hole in sequence.

[0018] In an embodiment of the utility model, the workpiece rotary support assembly further comprises a first rotary shaft rotatably connected to the bottom support; the first rotary shaft is coaxially connected to the support disc; the first rotary shaft is provided with a first hollow structure; the support disc is provided with a first through hole in communication with the first hollow structure; the first through hole is in communication with the mounting groove; the cooling circulation system supplies polishing liquid to the disc surface of the support disc through the first hollow structure and the first through hole in sequence. The grinding disc component further comprises a second rotary shaft rotatably connected to the bottom support; the second rotary shaft is coaxially connected to the polishing disc; the second rotary shaft is provided with a second hollow structure; the polishing disc is provided with a second through hole in communication with the second hollow structure; the cooling circulation system supplies polishing liquid to the disc surface of the polishing disc through the second hollow structure and the second through hole in sequence.

[0019] In an embodiment of the utility model, in the case that the first through hole is arranged on the support disc: a plurality of longitudinal and transverse intersecting flow guide grooves are arranged on the surface of the mounting groove parallel to the disc surface of the support disc; the flow guide grooves are in communication with the first through hole.

[0020] In one embodiment of the present application, the polishing disc is provided with a second through hole; the disc surface of the polishing disc is also provided with a flow guide groove, and the flow guide groove is in communication with the polishing disc.

[0021] In one embodiment of the present application, the first through hole is provided on the support disc; a plurality of longitudinal and transverse intersecting flow guide grooves are provided on the surface of the mounting groove which is parallel to the disc surface of the support disc; the flow guide grooves are in communication with the first through hole; the second through hole is provided on the polishing disc; the disc surface of the polishing disc is also provided with a flow guide groove, and the flow guide groove is in communication with the polishing disc.

[0022] In one embodiment of the present application, the movable vacuum flip loading and unloading support is further included; the sealed cabin is provided with a side door which can be opened and closed; the vacuum flip loading and unloading support enters and exits the sealed cabin through the side door, and is used for loading and unloading the workpiece to be processed to the support disc.

[0023] In one embodiment of the present application, the vacuum flip loading and unloading support comprises a rack, a moving component, a vacuum device, a flip rack and a plurality of suction cups; the moving component is arranged at the bottom of the rack and is used for driving the rack to move; the vacuum device is arranged at the top of the rack; the height of the flip rack is adjustable; the flip rack is rotationally connected to the rack and rotates in a vertical plane; the plurality of suction cups are arranged in an array on the flip rack, and the suction cups are connected to the vacuum device.

[0024] In one embodiment of the present application, the vacuum flip loading and unloading support further comprises a rotating shaft, an outer shaft sleeve and a locking nut; the rotating shaft is rotationally connected to the rack through the outer shaft sleeve, and a threaded hole is arranged on the rotating shaft; an arc-shaped groove is arranged on the end face of the outer shaft sleeve, and the arc-shaped groove is concentric with the rotating shaft; the locking nut is connected to the threaded hole through the arc-shaped groove.

[0025] In one embodiment of the present application, the workpiece rotary support assembly further comprises a pressure sensor, which is used for monitoring the pressure received by the workpiece to be processed when the workpiece to be processed is clamped by the polishing disc and the support disc.

[0026] In one embodiment of the present application, the support disc and the polishing disc are immersed in the polishing liquid in the sealed cabin, and the immersion depth is 100-300 mm.

[0027] In one embodiment of the present application, the cooling circulation system comprises a water tank, a stirrer, a cooler and a liquid pump; the water tank is in communication with the sealed cabin; the stirrer, the cooler and the liquid pump are all arranged in the water tank, the stirrer is located at the middle part of the water tank, the cooler is located at one end of the water tank which is close to the sealed cabin, and the liquid pump is arranged at the other end of the water tank which is away from the sealed cabin; the liquid pump is in communication with the sealed cabin through a pipeline.

[0028] In an embodiment of the utility model, the grinding disc part further 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 is matched with the ball screw, and the screw nut is connected to the bottom of the double-shaft grinding disc assembly.

[0029] The above technical scheme of the utility model has the following advantages compared with the prior art:

[0030] 1. The polishing disc and the supporting disc are vertically arranged, 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 self-gravity of the quartz piece (workpiece to be processed), effectively improving the polishing plane processing precision and increasing the yield.

[0031] 2. During the polishing process, the cooling circulation system supplies the polishing liquid (cooling liquid) to the supporting disc and the polishing disc, so that the supporting disc and the polishing disc are always in a fully cooled state, effectively reducing the local thermal deformation during processing and avoiding the change in flatness after the disc, thereby ensuring the stability and precision of the workpiece to be processed.

[0032] 3. The application clamps the workpiece to be processed by the rotational friction of the two polishing discs and the supporting disc, without using hard bonding or fastening clamping, thereby solving the deformation problem caused by clamping, reducing the deformation in the thickness direction of the quartz piece, effectively improving the polishing plane precision and reducing the probability of material breakage.

[0033] 4. The application sets two polishing discs, which are moved back and forth along the Y direction during the polishing process, thereby effectively and uniformly polishing the surface of the workpiece to be processed. The use of a single large-size polishing disc is avoided, the diameter of the polishing disc is reduced by 50%, and the production difficulty and cost are greatly reduced. In addition, since the diameter of the polishing disc is reduced and the working surface of the polishing disc is perpendicular to the horizontal plane, the requirement for resisting gravity deformation is reduced, and the thickness of the polishing disc can be reduced by 48.3% to 72.5%, further reducing the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to make the content of the utility model more easily understood, the utility model will be further described in detail below according to the specific embodiments of the utility model and in combination with the drawings, in which:

[0035] Figure 1 is a structure schematic view of a large-size photomask quartz glass substrate polishing device in the preferred embodiment of the utility model;

[0036] Figure 2 is Figure 1 the internal schematic view of the sealed cabin in the large-size photomask quartz glass substrate polishing device;

[0037] Figure 3 is Figure 1 a structure diagram of a sealed cabin and a cooling circulation system in a large-size photomask quartz glass substrate polishing device;

[0038] Figure 4 is Figure 1 a front view of a vacuum flip loading and unloading support in a large-size photomask quartz glass substrate polishing device;

[0039] Figure 5 is Figure 1 a side view of a vacuum flip loading and unloading support in a large-size photomask quartz glass substrate polishing device;

[0040] Figure 6 is Figure 1 a structure diagram of a support disc in a large-size photomask quartz glass substrate polishing device;

[0041] Figure 7 is Figure 1 a sectional view of a support disc in a large-size photomask quartz glass substrate polishing device;

[0042] Description of the drawing: 100, bottom support;

[0043] 200, workpiece rotation support assembly; 210, first rotation shaft; 211, first hollow structure; 220, first rotation power part; 221, main shaft motor; 222, driving gear; 223, driven gear; 224, speed reducer; 230, support disc; 231, mounting groove; 232, first through hole; 233, flow guide groove; 240, first support part; 241, first base; 242, first support seat; 250, positioning lug; 260, first sliding power part; 270, first porous polyurethane substrate; 280, pressure sensor; 290, guide part;

[0044] 300, double-shaft grinding disc assembly; 310, second rotation shaft; 311, second through hole; 312, second hollow structure; 320, second rotation power part; 330, polishing disc; 340, second support part; 341, second base; 342, second support seat; 350, second sliding power part; 360, second porous polyurethane substrate;

[0045] 400, sealed cabin; 410, side door; 420, backflow port; 430, polishing liquid layer;

[0046] 500, cooling circulation system; 510, water tank; 520, stirrer; 530, cooler; 540, liquid pump; 550, pipeline; 551, control valve;

[0047] 600, workpiece to be processed;

[0048] 700, vacuum flip handling support; 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 rail; 770, rotary power part; 771, rotating shaft; 772, outer shaft sleeve; 7721, arc-shaped groove; 7722, flange; 773, locking nut; 774, handle; 780, air pipe. DETAILED DESCRIPTION

[0049] The utility model will be further explained in connection with the drawings and specific embodiments, so that the person skilled in the art can better understand the utility model and can be implemented, but the embodiment is not as the limitation of the utility model.

[0050] In some comparative examples, there are the following problems: ① Because the quartz sheet is thin and large in area, warping deformation often occurs due to gravity during processing, which greatly affects the processing precision, and even may lead to processing scrap, seriously affecting the yield of polished products; ② During polishing, the quartz sheet and the clamping tooling may produce slight deformation due to clamping stress and heating, which will disappear after the lower disc of the quartz sheet is cooled, resulting in changes in the precision of the lower disc of the quartz sheet, affecting the precision of the finished product; ③ The polishing disc base of the traditional polishing method is generally made of whole marble material, and the radius thereof is required to be not less than the diagonal diameter of the quartz sheet, so that the polishing disc is too large in diameter, and the production and processing difficulties are great, and the cost is high.

[0051] Referring to Figures 1-7 The utility model embodiment provides a kind of large size photomask quartz glass substrate polishing device, it include:

[0052] Bottom support piece 100 is as main bearing part;

[0053] Workpiece rotary support assembly 200 is slidably connected to the top of one end of bottom support piece 100 in X direction in horizontal plane (XY plane);Workpiece rotary support assembly 200 includes first rotary shaft 210, first rotary power part 220 and rotatable support disc 230;One end of first rotary shaft 210 is connected with first rotary power part 220, and the other end is connected with support disc 230;The disc surface of support disc 230 is provided with mounting groove 231, for installing workpiece 600 to be processed;In some embodiments, the size of mounting groove 231 is 1-2mm greater than the corresponding size of workpiece 600 to be processed, and the depth of mounting groove 231 is 1 / 2 of the thickness of workpiece.The plane of mounting groove 231 in contact with workpiece 600 to be processed requires 000 level of plane precision, and the rotary runout is better than 0.005mm.

[0054] The biaxial grinding disc assembly 300 is slidably connected to the top of the other end of the bottom support 100 in the Y direction in the horizontal plane. The biaxial grinding disc assembly 300 comprises two grinding disc components arranged side by side in the Y direction, and the grinding disc components comprise a second rotary shaft 310, a second rotary power part 320 and a rotatable polishing disc 330. One end of the second rotary shaft 310 is connected to the second rotary power part 320, and the other end is connected to the polishing disc 330. The polishing disc 330 is arranged opposite to the support disc 230. The axis of the polishing disc 330 is aligned with the axis of the support disc 230, and the height of the polishing disc 330 is flush with the height of the support disc 230. The diameter of the polishing disc 330 is similar to the maximum diameter of the workpiece 600 to be processed.

[0055] The sealed cabin 400 is arranged on the top of the bottom support 100 and is connected to the bottom support 100 by screws. In the X direction, the two sides of the sealed cabin 400 are respectively provided with holes, and the first rotary shaft 210 and the second rotary shaft 310 pass through the holes through shaft sleeves. The polishing disc 330 and the support disc 230 are arranged in the sealed cabin 400.

[0056] The cooling circulation system 500 is connected to the sealed cabin 400 and is used to supply polishing liquid to the support disc 230 and the polishing disc 330.

[0057] In the application, the workpiece rotary support assembly 200 slides to the biaxial grinding disc assembly 300 to clamp the workpiece 600 to be processed. The polishing disc 330 and the support disc 230 rotate in the plane perpendicular to the horizontal plane to process the workpiece 600 to be processed.

[0058] The application has the following beneficial effects:

[0059] 1. The polishing disc 330 and the support disc 230 are arranged vertically in the application, 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 self-gravity of the quartz piece (the workpiece 600 to be processed), effectively improving the polishing plane processing precision and improving the yield.

[0060] 2. In the polishing process of the application, the cooling circulation system 500 supplies polishing liquid (cooling liquid) to the support disc 230 and the polishing disc 330, so that the support disc 230 and the polishing disc 330 are always in a fully cooled state, effectively reducing the local thermal deformation in the processing process and avoiding the change of flatness after the disc, thereby ensuring the stability and precision of the workpiece 600 to be processed.

[0061] 3. The two polishing discs 330 and the support disc 230 of the application are clamped by the rotary friction, which does not need to use the hard bonding or fastening clamping mode, thereby solving the deformation problem caused by clamping, reducing the deformation in the thickness direction of the quartz piece, effectively improving the polishing plane precision and reducing the probability of material breakage.

[0062] 4. The application sets two polishing discs 330, which effectively and uniformly polish the surface of the workpiece 600 to be processed by reciprocating along the Y direction during polishing. The application avoids the use of a single large polishing disc 330, reduces the diameter of the polishing disc 330 by 50%, and greatly reduces the production difficulty and cost. In addition, due to the reduction of the diameter of the polishing disc 330, the working surface of the polishing disc 330 is perpendicular to the horizontal plane, reducing the need to resist gravity deformation, so that the thickness of the polishing disc 330 can be reduced by 48.3%~72.5%, further reducing the production cost.

[0063] Therefore, the application solves the problems of gravity deformation and heat deformation during polishing, improves the overall quality and yield of the mask substrate, and reduces the requirements for the size of the polishing disc and the cost.

[0064] In some embodiments, the polishing disc 330 is arranged vertically to the horizontal plane, and the perpendicularity of the polishing disc 330 is 90°±1°. The support disc 230 is arranged vertically to the horizontal plane, and the perpendicularity of the support disc 230 is 90°±1°.

[0065] In some embodiments, the diameter D1 of the support disc 230 is D2+D2 / 20, and the thickness H1 of the support disc 230 is 1 / 30~1 / 20 of its diameter D1.

[0066] In some embodiments, the diameter D3 of the polishing disc 330 is D2+D2 / 20, and the thickness H3 of the polishing disc 330 is 1 / 30~1 / 20 of its diameter D3. The surface of the polishing disc 330 in contact with the workpiece 600 has a surface accuracy of 000 level and a rotary runout of better than 0.005mm.

[0067] In some embodiments, the support disc 230 and the polishing disc 330 are made of the same material, and the main body material of the two is marble. Specifically, fine-grained, dense-structured gabbro, diabase, granite (biotite should be less than 5%, elastic modulus should be greater than 0.6x10 -4 kg / square centimeter, water absorption should be less than 0.25%) and other materials are used to manufacture, and the working surface hardness should be greater than 70Hs.

[0068] In some embodiments, the workpiece rotary support assembly 200 further comprises a first support part 240, which comprises a first base 241 and at least one first support seat 242. The first base 241 is horizontally arranged and is in sliding connection with the bottom support 100. The first support seat 242 is vertically arranged and is connected to the top of the first base 241. The first rotary shaft 210 is rotatably connected to the top end of the first support seat 242 by a bearing. In some embodiments, the double-axis grinding disc assembly 300 further comprises a second support part 340. The second support part 340 has the same structure as the first support part 240. That is, the second support part 340 comprises a second base 341 and at least one second support seat 342. The second base 341 is horizontally arranged and is in sliding connection with the bottom support 100. The second support seat 342 is vertically arranged and is connected to the top of the second base 341. The second rotary shaft 310 is rotatably connected to the top end of the second support seat 342 by a bearing. Specifically, the first support part 240 provides support for the first rotary power part 220, the first rotary shaft 210, etc. Similarly, the second support part 340 provides support for the second rotary power part 320, the second rotary shaft 310, etc.

[0069] In some embodiments, the workpiece rotary support assembly 200 further comprises a positioning lug 250. The positioning lug 250 is concentric with the support disc 230. The positioning lug 250 is fixed to the back of the support disc 230 (i.e. the side of the support disc 230 facing the first rotary shaft 210) by screws. The positioning lug 250 is connected to the first rotary shaft 210 by a sealing ring and screws. In addition, the grinding disc assembly also comprises a positioning lug, which is connected to the grinding disc assembly in the same way as the workpiece rotary support assembly 200, which will not be described here.

[0070] Further, the workpiece rotary support assembly 200 further comprises a first sliding power part 260. The first sliding power part 260 is connected to the bottom support 100, and the output shaft of the first sliding power part 260 is connected to the first base 241 of the workpiece rotary support assembly 200. In some embodiments, the first sliding power part 260 is a pneumatic cylinder. Specifically, the workpiece rotary support assembly 200 can be controlled to move back and forth along the X direction on the bottom support 100 by the pneumatic cylinder. The structure is simple, the operation is stable and reliable, and the cost is low.

[0071] Further, the grinding disc component further comprises a second sliding power part 350, which comprises 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 is matched with the ball screw, and the screw nut is connected to the bottom of the second base 341 of the double-shaft grinding disc assembly 300. The motor drives the ball screw to rotate, thereby driving the screw nut and the second base 341 of the double-shaft grinding disc assembly 300 to slide on the bottom support 100 synchronously.

[0072] Further, the workpiece rotating support assembly 200 further comprises a guide component 290, which comprises a linear guide rail and a sliding block; the linear guide rail is connected to the top of the bottom support 100, the sliding block is connected to the bottom of the first base 241 of the workpiece rotating support assembly 200, and the sliding block is matched with the linear guide rail. In some embodiments, the grinding disc component also comprises a guide component, and the structure of the guide assembly of the guide component is the same as that of the workpiece rotating support assembly 200. Here, it will not be repeated. Specifically, the guide component can provide a guiding effect, thereby making the workpiece rotating support assembly 200 and the double-shaft grinding disc assembly 300 slide more smoothly and stably on the bottom support 100.

[0073] Further, the first rotating power part 220 comprises a main shaft motor 221, a driving gear 222 and a driven gear 223; the main shaft motor 221 is connected to the first base 241, the output shaft of the main shaft motor 221 is connected to the driving gear 222, the driven gear 223 is engaged with the driving gear 222, and the driven gear 223 is coaxially connected with the first rotating shaft 210. In some embodiments, the first rotating power part 220 further comprises a speed reducer 224, which is connected to the output shaft of the main shaft motor 221, and the output shaft of the speed reducer 224 is connected to the driving gear 222. In some other embodiments, the main shaft motor 221 is connected to the first rotating shaft 210 through a driving pulley and a driven pulley, which is a prior art and will not be repeated here. Specifically, the main shaft motor 221 provides rotating power, which is then transmitted to the first rotating shaft 210 through the driving gear 222 and the driven gear 223, thereby driving the first rotating shaft 210 to rotate forward or reverse at a process speed. Its structure is stable and reliable, and the cost is low. In some embodiments, the structure of the second rotating power part 320 is the same as that of the first rotating power part 220, which will not be repeated here.

[0074] Further, the first rotary shaft 210 is a hollow shaft, the first rotary shaft 210 is provided with a first hollow structure 211, the support disc 230 is provided with a first through hole 232 in communication with the first hollow structure 211, and the first through hole 232 is in communication with the mounting groove 231; the cooling circulation system 500 supplies the polishing liquid to the disc surface of the support disc 230 from the first hollow structure 211 and the first through hole 232. The second rotary shaft 310 is a hollow shaft, the second rotary shaft is provided with a second hollow structure 312; the polishing disc 330 is provided with a second through hole 311 in communication with the second hollow structure 312; the cooling circulation system 500 supplies the polishing liquid to the disc surface of the polishing disc 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.

[0075] Specifically, the first hollow structure 211 in the first rotary shaft 210 and the first through hole 232, the second hollow structure 312 in the second rotary shaft 310 and the second through hole 311 can supply the polishing liquid to the center of the disc surface of the support disc 230 and the polishing disc 330 respectively, which can improve the uniformity of the distribution of the polishing liquid on the polishing surface. In addition, the polishing liquid flows along the disc 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 bottoms of the support disc 230 and the polishing disc 330 can be immersed in the polishing liquid layer 430. The bottom of the polishing disc 330 and the bottom of the support disc 230 are partially immersed below the liquid level, so that the support disc 230 and the polishing disc 330 are further cooled and wetted. And during the rotary polishing process of the support disc 230 and the polishing disc 330, the polishing liquid is stirred, so as to continuously lubricate the disc surface of the support disc 230 and the polishing disc 330, improve the settlement problem of the polishing liquid, and optimize the concentration distribution of the polishing liquid. Therefore, the polishing effect and precision are further improved.

[0076] Further, in the case that the first through hole 232 is arranged on the support disc 230, a plurality of longitudinal and transverse intersecting flow guide grooves 233 are arranged on the surface of the mounting groove 231 parallel to the disc surface of the support disc 230, and the flow guide grooves 233 are in communication with the first through hole 232. In the case that the second through hole 311 is arranged on the polishing disc 330, flow guide grooves are also arranged on the disc surface of the polishing disc 330, and the flow guide grooves are in communication with the polishing disc 330. In some embodiments, the depth of the flow guide grooves 233 on the support disc 230 is 3-5 mm, and the width is 3-5 mm. The depth of the flow guide grooves on the polishing disc 330 is 0.5 mm, and the width is 1 mm. Specifically, the flow guide grooves 233 arranged in the embodiment enable the polishing liquid to be quickly and uniformly distributed in the mounting groove 231 and on the disc surface of the polishing disc 330, thereby further uniformly cooling the support disc 230 and the polishing disc 330.

[0077] Further, the 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 the 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 1-0.5 mm. The 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 1-1.5 mm. The first porous polyurethane substrate 270 and the second porous polyurethane substrate 360 have the same effect. The porous polyurethane substrate can play an auxiliary polishing role. Since the surface of the porous polyurethane substrate is a porous structure, the time of the particles in the polishing liquid acting on the polishing surface during the polishing process can be prolonged, thereby further improving the polishing efficiency. In addition, since the material of the support disc 230 is marble, the porous polyurethane substrate is arranged to play a buffering role.

[0078] Further, the application also includes a movable vacuum flip loading and unloading support 700; the sealed cabin 400 is provided with openable side doors 410; the side doors 410 can be two, and the two side doors 410 are arranged on the two sides of the sealed cabin 400 along the Y axis. The side doors 410 can be opened and closed by 180°. For example, the side doors 410 are opened upward. The vacuum flip loading and unloading support 700 enters and exits the sealed cabin 400 from the side doors 410, and is used for loading and unloading the workpiece 600 to be processed to the support disc 230. In some embodiments, the vacuum flip loading and unloading support 700 includes a rack 710, a moving part 720, a vacuum device 730, a flipper 740, and a plurality of suction cups 750. The moving part 720 is arranged at the bottom of the rack 710 and is used to drive the rack 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 rack 710, and the required negative pressure is not less than -0.99kp. The height of the flipper 740 is adjustable; the length of the flipper 740 needs to ensure that it can enter the sealed cabin 400 and make the workpiece 600 to be processed adsorbed on the suction cup 750 be able to dock into the mounting groove 231. The flipper 740 is rotationally connected to the rack 710, and the flipper 740 rotates in a vertical plane. The suction cup 750 is a plurality of suction cups 750 arranged in an array on the flipper 740, and the suction cup 750 is connected to the vacuum device 730 through an air pipe 780. Specifically, the embodiment realizes the feeding and taking of the workpiece 600 to be processed through the vacuum flip loading and unloading support 700, which is convenient and fast, and will not cause damage to the workpiece 600 to be processed or cause deformation to affect the processing precision.

[0079] In some embodiments, the vacuum flip loading and unloading support 700 is also provided with an L-shaped table top (not shown in the figure), which is used to place the workpiece 600 to be processed in standby.

[0080] Further, the vacuum flip loading and unloading support 700 also includes a lifting part 760, which includes a gear 761 and a rack 762 engaged with the gear 761. The gear 761 is rotationally connected to the rack 710, and the rack 762 is vertically arranged on the flipper 740. In a possible implementation, a rocker 763 is arranged on the gear 761. By manually rotating the rocker 763, the gear 761 is rotated, thereby driving the flipper 740 to rise and fall. In another possible implementation, the gear 761 is connected with a motor, and the gear 761 is rotated by the motor. Specifically, the structure of the embodiment is stable and reliable.

[0081] Further, the lifting part 760 also includes a linear guide rail 764 connected between the rack 710 and the flipper 740, thereby providing a guiding effect.

[0082] Further, the vacuum flip handling support 700 further comprises a rotating power part 770; the rotating power part 770 comprises a rotating shaft 771, an outer shaft sleeve 772 and a locking nut 773. The rotating shaft 771 is rotatably connected with the frame 710 through the outer shaft sleeve 772, and the rotating shaft 771 is provided with a threaded hole; the end face of the outer shaft sleeve 772 is provided with an arc-shaped groove 7721, and the arc-shaped groove 7721 is concentric with the rotating shaft 771. In some embodiments, the end face of the outer shaft sleeve 772 is inwardly turned to form a turn-up edge 7722 which is arranged on the end of the rotating shaft 771. The locking nut 773 is connected with the threaded hole through the arc-shaped groove 7721. In some possible implementations, the rotating shaft 771 is provided with a handle 774, so that the rotating shaft 771 is driven to rotate through the handle 774, and the structure is simple and the cost is low. In other possible implementations, the rotating shaft 771 is connected with a power component (for example, a motor), and the power component drives the rotating shaft 771 to rotate, so that the control is automatic. Specifically, when the rotating shaft 771 needs to be rotated in the embodiment, the locking nut 773 is loosened, and then the rotating shaft 771 is rotated to drive the flip frame 740 to rotate. When the rotating shaft 771 is rotated to the target position, the locking nut 773 is tightened to fix the rotating shaft 771, so that the rotating shaft 771 is prevented from rotating. As can be seen, the rotating shaft 771 is driven to rotate in the embodiment, so that the flip frame 740 is synchronously rotated, and the structure is simple and the operation is convenient and fast.

[0083] Further, the workpiece rotary support assembly 200 further comprises a pressure sensor 280 for monitoring the pressure borne by the workpiece 600 when the polishing disc 330 and the support disc 230 clamp the workpiece 600. In some possible implementations, the workpiece rotary support assembly 200 moves reciprocatingly on the bottom support 100 through a cylinder. The pressure borne by the workpiece 600 is monitored through the pressure sensor 280, so that the pressure borne by the workpiece 600 can be monitored. Specifically, the pressure borne by the workpiece 600 is monitored through the pressure sensor 280 in the embodiment, so that the damage to the workpiece 600 caused by the excessive clamping force can be avoided under the condition that the workpiece 600 is clamped.

[0084] Further, the support disc 230 and the polishing disc 330 are immersed in the polishing liquid in the sealed cabin 400, and the immersion depth is 100-300 mm. That is, the height of the backflow port 420 (described below) is higher than the lowermost ends of the support disc 230 and the polishing disc 330 by 100-300 mm. Specifically, the rotation of the support disc 230 and the polishing disc 330 can be ensured while the cooling effect is ensured (because if the immersion depth is too large, the rotation of the support disc 230 and the polishing disc 330 will be subjected to excessive resistance, and if the immersion depth is too small, the cooling effect will be poor).

[0085] Further, the cooling circulation system 500 comprises a water tank 510, a stirrer 520, a cooler 530 and a liquid pump 540. The water tank 510 is in communication with the sealed cabin 400; the stirrer 520, the cooler 530 and the liquid pump 540 are all arranged in the water tank 510. The stirrer 520 is arranged at the middle of the water tank 510, the cooler 530 is arranged at one end of the water tank 510 close to the sealed cabin 400, and the liquid pump 540 is arranged at the other 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 arranged at the top of the water tank 510, and correspondingly, a backflow port 420 is arranged at the bottom of the sealed cabin 400, and a plate member is arranged at the backflow port 420 and inclined downward from the inside of the sealed cabin 400 to the outside of the sealed cabin 400, and the free end of the plate member is located directly above the opening. In other embodiments, the backflow port 420 is connected with the opening through the pipeline 550. Specifically, the polishing liquid with a higher temperature in the sealed cabin 400 is backflowed to the water tank 510, and then the polishing liquid with a lower temperature in the water tank 510 is mixed with the backflowed polishing liquid through the stirrer 520, so that the temperature of the backflowed polishing liquid is reduced, and finally the polishing liquid after temperature reduction is delivered to the support disc 230 and the polishing disc 330 through the liquid pump 540. Therefore, the cooling circulation system 500 can supply the polishing liquid to the sealed cabin 400 in circulation, and the polishing cooling can be realized.

[0086] It should be noted that when the first rotary shaft 210 and the second rotary shaft 310 are hollow shafts, the liquid pump 540 is in communication with the first rotary shaft 210 and the second rotary shaft 310 through pipelines (for example, hoses) respectively. The pipelines are provided with corresponding control valves 551, so that whether to supply the liquid to the support disc 230 and the polishing disc 330 and the flow rate of the liquid are adjusted through the control valves 551.

[0087] The process of polishing by using the present application is as follows:

[0088] 1. Ensure that the water tank 510 of the cooling circulation system 500 is filled with polishing liquid, and the main component of the polishing liquid is cerium oxide, and the solid content is 15%-30%. Turn on the cooler 530 and the stirrer 520 of the cooling circulation system 500, and open the cylinder control to move the workpiece rotary support assembly 200 on the bottom support 100, so that the workpiece rotary support assembly 200 moves away from the double-shaft polishing disc assembly 300;

[0089] 2. The total flow rate of the cooling polishing liquid is 80-220 L / min, and the temperature of the polishing liquid is set to 23±0.5℃;

[0090] 3. The quartz piece (workpiece 600) after the grinding and cleaning is completed, is vertically leaned on the L-shaped table, the vacuum flip loading and unloading support 700 is moved and the height of the flipper 740 is adjusted to ensure that the suction cup 750 is tightly attached to the surface of the quartz piece;

[0091] 4. The vacuum device 730 is opened, the flipper 740 is raised so that the quartz piece is lifted, the side door 410 of the sealed cabin 400 is opened, the vacuum flip loading and unloading support 700 is moved into the sealed cabin 400, and the quartz piece is placed in the mounting groove 231 of the workpiece rotating support assembly 200;

[0092] 5. The plastic sheet is used to resist the quartz piece to avoid falling and falling. The vacuum device 730 is closed to release the suction cup 750, and then the vacuum flip loading and unloading support 700 can be removed;

[0093] 6. The control valve 551 of the cooling liquid (polishing liquid) of the double-axis polishing disc assembly 300 is opened, so that the cooling liquid (polishing liquid) flows out from the second through hole 311 of the two polishing discs 330 and covers the entire polishing surface. The cylinder is opened to move the workpiece rotating support assembly 200 on the bottom support 100, so that the workpiece rotating support assembly 200 approaches the double-axis polishing disc assembly 300, when the distance between them is close, the plastic sheet is removed, until the workpiece rotating support assembly 200 and the disc surface of the double-axis polishing disc assembly 300 are tightly clamped to clamp the workpiece 600. Then the side door 410 of the sealed cabin 400 is closed, and the pressure of the cylinder can be set to 10-50 kg. Mark the position of the workpiece rotating support assembly 200 on the guide rail of the bottom support 100 at this time;

[0094] 7. The control valve 551 of the workpiece rotating support assembly 200 is opened, so that the cooling liquid flows out from the first through hole 232 of the support disc 230, and then the mounting groove 231 covers the entire disc surface, so that the entire workpiece 600 is uniformly cooled. The support disc 230 is controlled to rotate, and the rotating speed is set to 5-8 rpm. The polishing disc 330 is controlled to rotate, and the rotating speed is set to 5-8 rpm. The rotating direction of the polishing disc 330 is opposite to that of the support disc 230. The double-axis polishing disc assembly 300 is controlled to move back and forth along the Y direction (i.e. the front and back direction), and the moving distance is greater than half of the maximum size (for square workpiece, it is the diagonal line; for circular workpiece, it is the diameter) of the workpiece 600, and the moving speed can be set to 100-300 mm / min;

[0095] 8. When all the motion starts, the cylinder pressure of the workpiece rotary support assembly 200 is adjusted to 60-100 kg, and the rotating speed of the workpiece rotary support assembly 200 and the disc (i.e. the support disc 230 and the polishing disc 330) of the double-axis polishing disc assembly 300 is adjusted to 15-20 rpm. The position change of the workpiece rotary support assembly 200 on the guide rail of the bottom support 100 is observed, so that the polished removal thickness can be determined;

[0096] 9. When the single-side polishing removal thickness approaches the target, the cylinder pressure of the workpiece rotary support assembly 200 is adjusted to 10-20 kg, and the rotating speed of the support disc 230 and the polishing disc 330 is adjusted to 5-8 rpm until the removal thickness meets the standard. The control is performed to move and stop the double-axis polishing disc assembly 300 at the center of the distance between the two polishing discs 330 and align the center of the workpiece 600 to be processed (convenient for taking out the workpiece), and then stop the rotation of the support disc 230 and the polishing disc 330, and close the control valve 551 of the workpiece rotary support assembly 200 and the double-axis polishing disc assembly 300;

[0097] 10. The two side doors 410 of the sealed cabin 400 are opened, and a plastic sheet is used to press against the quartz sheet (the workpiece 600 to be processed) to prevent it from falling and falling. At the same time, the cylinder is started to move the workpiece rotary support assembly 200 away from the double-axis polishing disc assembly 300;

[0098] 11. The vacuum overturning loading and unloading support 700 is moved into the sealed cabin 400, and the suction cups 750 are fully attached to the quartz sheet, the vacuum device 730 is opened to make the suction cups 750 suck the quartz sheet, so that the vacuum overturning loading and unloading support 700 is moved to take out the quartz sheet and place it on the L-shaped table top. The vacuum device 730 is closed, and the overturning frame 740 of the vacuum overturning loading and unloading support 700 is overturned by 180°;

[0099] 12. The polished surface of the quartz sheet is wiped clean, and the disc surface of the support disc 230 is cleaned;

[0100] 13. The polished surface of the quartz sheet is adsorbed by using the vacuum overturning loading and unloading support 700, and then the overturning frame 740 of the vacuum overturning loading and unloading support 700 and the quartz sheet are overturned by 180°, and the above steps 3-12 are repeated;

[0101] 14. The quartz sheet polished on both sides is cleaned and inspected.

[0102] In some embodiments, after polishing by using the utility model, the flatness of the polished surface is generally better than 20 μm, and the average can reach 5-15 μm.

[0103] Obviously, the above embodiments are only examples for clearly illustrating the present application, and are not intended to limit the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A polishing apparatus for large-size photomask quartz glass substrates, characterized in that: The application relates to a polishing device, which comprises the following parts: a bottom support; a workpiece rotary support assembly, which is connected to the top of one end of the bottom support and slides along the X direction in the horizontal plane; the workpiece rotary support assembly comprises a rotatable support disc; the disc surface of the support disc is provided with a mounting groove for mounting a workpiece to be processed; a double-shaft polishing disc assembly, which is connected to the top of the other end of the bottom support and slides along the Y direction in the horizontal plane; the double-shaft polishing disc assembly comprises two polishing disc components arranged side by side along the Y direction; the polishing disc components comprise rotatable polishing discs; the polishing discs are arranged face to face with the support disc; the polishing disc and the support disc have the same height of the axis; a sealed cabin, which is arranged on the top of the bottom support; the polishing disc and the support disc are arranged in the sealed cabin; a cooling circulation system, which is connected to the sealed cabin and is used for supplying polishing liquid to the support disc and the polishing disc; wherein the workpiece rotary support assembly slides towards the double-shaft polishing disc assembly to clamp the workpiece to be processed; the polishing disc and the support disc rotate in the plane perpendicular to the horizontal plane to process the workpiece to be processed.

2. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 1, wherein: The workpiece rotary support assembly further comprises a first rotary shaft which is rotatably connected to the bottom support; the first rotary shaft is coaxially connected to the support disc; the first rotary shaft is provided with a first hollow structure; the support disc is provided with a first through hole which is in communication with the first hollow structure; the first through hole is in communication with the mounting groove; the cooling circulation system supplies polishing liquid to the disc surface of the support disc through the first hollow structure and the first through hole in sequence; and / or the polishing disc component further comprises a second rotary shaft which is rotatably connected to the bottom support; the second rotary shaft is coaxially connected to the polishing disc; the second rotary shaft is provided with a second hollow structure; the polishing disc is provided with a second through hole which is in communication with the second hollow structure; the cooling circulation system supplies polishing liquid to the disc surface of the polishing disc through the second hollow structure and the second through hole in sequence.

3. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 2, wherein: In the case that the first through hole is arranged on the support disc: a plurality of longitudinal and transverse intersecting flow guide grooves are arranged on the surface of the mounting groove which is parallel to the disc surface of the support disc; the flow guide grooves are in communication with the first through hole; and / or in the case that the second through hole is arranged on the polishing disc: the disc surface of the polishing disc is also provided with flow guide grooves which are in communication with the polishing disc.

4. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 1, wherein: The application further comprises a movable vacuum flip loading and unloading support; the sealed cabin is provided with an openable and closable side door; the vacuum flip loading and unloading support enters and exits the sealed cabin through the side door to load and unload the workpiece to be processed on the support disc.

5. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 4, wherein: The vacuum flip loading and unloading support comprises 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 rotates in the vertical plane; the plurality of suction cups are arranged on the flip frame in an array and are connected to the vacuum device.

6. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 5, wherein: The vacuum turnover loading and unloading support further comprises a rotating shaft, an outer shaft sleeve and a locking nut; the rotating shaft is rotationally connected with the support frame through the outer shaft sleeve, and a threaded hole is arranged on the rotating shaft; an end surface of the outer shaft sleeve is provided with an arc-shaped groove, and the arc-shaped groove is concentric with the rotating shaft; the locking nut is connected with the threaded hole through the arc-shaped groove.

7. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 1, wherein: The workpiece rotary support assembly further comprises a pressure sensor for monitoring the pressure received by the workpiece when the polishing disc and the support disc clamp the workpiece.

8. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 1, wherein: The support disc and the polishing disc are immersed in the polishing liquid in the sealed cabin, and the immersion depth is 100-300 mm.

9. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 1, wherein: The cooling circulation system comprises a water tank, a stirrer, a cooler and a liquid pump; the water tank is in communication with the sealed cabin; the stirrer, the cooler and the liquid pump are all arranged in the water tank, the stirrer is located at 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 the other end of the water tank away from the sealed cabin; the liquid pump is in communication with the sealed cabin through a pipeline.

10. The polishing apparatus for polishing a large-sized photomask quartz glass substrate according to claim 1, wherein: The grinding disc component further comprises a motor, a ball screw and a screw nut; the motor is connected with the top of the bottom support, the output shaft of the motor is connected with the ball screw, the screw nut is matched with the ball screw, and the screw nut is connected with the bottom of the double-shaft grinding disc assembly.

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