Polishing bearing platform based on vacuum adsorption and water cooling circulation

Abstract

The invention discloses a polishing bearing platform based on vacuum adsorption and water cooling circulation. The polishing bearing platform comprises a rotating main shaft; the cold water disc is fixed to the upper end of the rotating main shaft, a cooling groove is formed in the upper end face of the cold water disc, and a first negative pressure channel, a first water inlet channel and a first water outlet channel are formed in the cold water disc in the axial direction in a penetrating mode, the vacuum chuck is fixed on the upper end surface of the cold water disc; a negative pressure groove is formed in the upper end face of the vacuum suction cup, and a second negative pressure channel connected with the second channel is formed in the vacuum suction cup in the axial direction in a penetrating mode. The ceramic disc is tightly attached to the upper end face of the vacuum suction cup; the rotating joint is mounted on the rotating main shaft and is provided with a second water inlet channel, a second water outlet channel and a third negative pressure channel; the second water inlet channel, the second water outlet channel and the third negative pressure channel are respectively communicated with the first water inlet channel, the first water outlet channel and the first negative pressure channel through connecting pipes; and a drive assembly. The invention has the characteristic of reasonable design.

Description

Technical Field

[0001] The invention belongs to the field of polishing processing, and in particular relates to a polishing bearing platform based on vacuum adsorption and water cooling circulation. Background Art

[0002] As semiconductor manufacturing processes advance to 3nm and below process nodes, extreme ultraviolet lithography (EUVL) technology has become a core solution to break through the physical limits of traditional optical lithography. Compared with 193nm deep ultraviolet (DUV) lithography, the EUVL system uses a 13.5nm extremely short wavelength light source to achieve higher resolution pattern transfer, but its technical implementation complexity increases exponentially. In this process, the mask substrate (ReticleSubstrate) is an important medium for carrying lithography patterns, and its performance directly affects the imaging quality and chip yield of the lithography machine.

[0003] In the EUVL system, the mask substrate needs to perform three core functions: (1) as the physical carrier of the multilayer film reflective structure, it needs to maintain the atomic-level flatness of the surface morphology; (2) resist the thermodynamic impact of the high-power laser plasma light source in a vacuum environment; (3) ensure the nanometer-level overlay accuracy during the pattern transfer process. Studies have shown that when the substrate surface roughness (Ra) exceeds 0.1nm, the reflectivity of the multilayer film will decrease by more than 5%, and the proximity effect error will increase by more than 30%. Therefore, the International Technology Roadmap for Semiconductors (IRDS) clearly requires that the surface roughness of the mask substrate for processes below 7nm must be controlled below 0.05nmRMS, and the local slope error must not exceed 0.25μrad.

[0004] In order to achieve the above performance indicators, the mask substrate needs to undergo a multi-stage precision polishing process. Sub-nanometer surface roughness can be achieved through traditional chemical mechanical polishing (CMP) technology. The polishing technology of domestic mask substrates is not yet mature, and there is no dedicated ultra-precision equipment for polishing mask substrates, resulting in low processing accuracy and poor surface quality of mask substrates, which cannot meet the requirements of various aspects of accuracy for the use performance of high-precision mask substrates.

[0005] In the ultra-precision polishing process of EUV lithography mask substrates, the flatness of the carrier platform is the core factor that determines the accuracy of the substrate surface topography. Due to the mechanical coupling effect between the mask substrate and the carrier platform, the platform flatness error will be directly transmitted to the substrate surface through the clamping force field. In addition, during the dynamic polishing process, insufficient platform flatness will aggravate the coupling effect of axial runout and thermal mechanical instability: on the one hand, the microscopic undulations of the platform in the rotating state will destroy the uniformity of the polishing liquid film, induce periodic pressure fluctuations, and cause the surface micro-waviness (<1μm wavelength) to exceed the standard; on the other hand, the mismatch of the thermal expansion coefficient (CTE) between the platform material and the substrate (such as the CTE difference between Invar alloy and quartz glass is as high as 0.05ppm / ℃) will produce nano-level cumulative deformation when the temperature fluctuates, further deteriorating the polishing surface accuracy. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a polishing bearing platform based on vacuum adsorption and water cooling cycle, which has the characteristics of reasonable design.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: A polishing bearing platform based on vacuum adsorption and water cooling cycle, comprising: a rotating spindle; A cold water pan fixed to the upper end of the rotating main shaft, the upper end surface of the cold water pan is provided with a cooling groove, the cold water pan is axially penetrated with a first negative pressure channel, and a first water inlet channel and a first water outlet channel connected with the cooling groove; A vacuum suction cup is fixed to the upper end surface of the cold water pan, and the bottom end surface and the cooling groove form a cooling cavity; the upper end surface of the vacuum suction cup is provided with a negative pressure groove, and the vacuum suction cup is axially penetrated with a second negative pressure channel connected with the second channel; A ceramic plate, which is in close contact with the upper end surface of the vacuum chuck, and the bottom end surface and the negative pressure groove form a negative pressure cavity; a rotary joint, which is mounted on the rotating main shaft and is provided with a second water inlet channel, a second water outlet channel and a third negative pressure channel; the second water inlet channel, the second water outlet channel and the third negative pressure channel are respectively connected with the first water inlet channel, the first water outlet channel and the first negative pressure channel through connecting pipes; And a driving assembly, used for driving the rotating main shaft to rotate.

[0008] Preferably, a first channel is axially penetrated through the middle of the rotating main shaft; The rotary joint is installed at the lower end of the rotating main shaft, and the second water inlet channel, the second water outlet channel and the third negative pressure channel are all connected to the first channel; The bottom of the cold water pan is provided with a mounting groove, and the upper end of the rotating main shaft is sealingly sleeved in the mounting groove; the lower ends of the first negative pressure channel, the first water inlet channel, and the first water outlet channel are all connected to the mounting groove.

[0009] Preferably, the first negative pressure channel is located on the central axis of the cold water pan, and the second negative pressure channel is located on the central axis of the vacuum suction cup.

[0010] Preferably, a first sealing groove is provided in the middle of the upper end surface of the cold water pan, a first sealing ring is provided in the first sealing groove, and the lower end surface of the vacuum suction cup is in close contact with the first sealing ring.

[0011] Preferably, the upper end surface of the cold water pan is provided with a second sealing groove, a second sealing ring is nested in the second sealing groove, and the lower end surface of the vacuum suction cup is in close contact with the second sealing ring.

[0012] Preferably, the upper end surface of the vacuum suction cup is provided with a third sealing groove, a third sealing ring is nested in the third sealing groove, and the lower end surface of the ceramic disc is in close contact with the third sealing ring.

[0013] Preferably, the driving assembly includes a driving motor, a motor seat, a driving wheel, a belt and a driven wheel; the driven wheel is fixedly mounted on the rotating main shaft, the driving motor is mounted on the motor seat, the driving wheel is mounted on the output end of the driving motor, and the belt is mounted on the driving wheel and the driven wheel.

[0014] Preferably, a bearing assembly is installed on the outer ring of the cold water pan, and the bearing assembly is provided with a sealing pressure plate.

[0015] The technical effects of the present invention are mainly reflected in the following aspects: 1. The carrier surface uses vacuum adsorption to isolate mechanical locking deformation, so that the carrier can maintain a 2μ level flatness; 2. A double-layer water-cooling circulation structure is added on the basis of vacuum adsorption to meet the requirements of dynamic high-speed processing and prevent the temperature rise caused by cutting and polishing from being too high and affecting the flatness of the bearing surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A three-dimensional modeling diagram of the polishing bearing platform in the embodiment; Figure 2 is a cross-sectional view of a polishing bearing platform in an embodiment; Figure 3 A schematic diagram of a cold water tray in an embodiment; Figure 4 Schematic diagram of the vacuum chuck in the embodiment.

[0017] Figure numerals: 1. motor base; 2. driving motor; 3. driving wheel; 4. belt; 5. driven wheel; 6. rotating joint; 61. second negative pressure channel; 62. second water inlet channel; 63. second water outlet channel; 7. rotating main shaft; 71. first channel; 8. bearing assembly; 9. sealing pressure plate; 10. cooling disk; 101. first water inlet channel; 102. second water outlet channel; 103. first negative pressure channel; 104. first sealing groove; 105. second sealing groove; 11. vacuum suction cup; 111. third negative pressure channel; 112. third sealing groove; 12. ceramic disk; 13. first sealing ring; 14. second sealing ring; 15. third sealing ring. DETAILED DESCRIPTION

[0018] The specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings to make the technical solutions of the present invention easier to understand and grasp.

[0019] Reference Figure 1 , Figure 2 The present embodiment provides a polishing bearing platform based on vacuum adsorption and water cooling cycle, including a driving assembly, a rotating spindle 7, a cold water plate, a vacuum suction cup 11, a ceramic plate 12 and a rotating joint 6. The driving assembly includes a driving motor 2, a motor seat, a driving wheel 3, a belt 4 and a driven wheel 5; the motor seat is installed on the equipment platform, the driven wheel 5 is fixedly sleeved on the rotating spindle 7, the driving motor 2 is installed on the motor seat, the driving wheel 3 is installed on the output end of the driving motor 2, and the belt 4 is sleeved on the driving wheel 3 and the driven wheel 5; by controlling the rotation of the driving motor 2, the rotating spindle 7 can be driven to rotate.

[0020] A first channel 71 is axially penetrated through the middle of the rotating main shaft 7 .

[0021] The rotary joint 6 is installed at the lower end of the rotating main shaft 7, and is equipped with a second water inlet channel 62, a second water outlet channel 102 and a third negative pressure channel 111; the second water inlet channel 62 is used for external cooling water, and the second water outlet channel 102 is used for drainage; the third negative pressure channel 111 is used for external negative pressure source. The second water inlet channel 62, the second water outlet channel 102 and the third negative pressure channel 111 are all connected to the first channel 71 (not shown in the figure), which can be understood as the upper channel openings of the second water inlet channel 62, the second water outlet channel 102 and the third negative pressure channel 111 are connected to the first channel 71.

[0022] The outer ring of the cold water pan is installed with a bearing assembly 8, which is then installed on the equipment platform (with corresponding mounting holes) through the bearing assembly 8 and can rotate freely. The bearing assembly 8 is equipped with a sealing plate 9, which can play a role in sealing and waterproofing.

[0023] The cold water pan is fixed to the upper end of the rotating main shaft 7. Specifically, the bottom of the cold water pan has a mounting groove, and the upper end of the rotating main shaft 7 is sealed and sleeved in the mounting groove, so that the cold water pan rotates with the rotating main shaft 7. A cooling groove is provided on the upper end surface of the cold water pan, and the cold water pan is axially penetrated with a first negative pressure channel 103, a first water inlet channel 101 and a first water outlet channel connected to the cooling groove; the first negative pressure channel 103 is located on the central axis of the cold water pan. The lower ends of the first negative pressure channel 103, the first water inlet channel 101 and the first water outlet channel are all connected to the mounting groove. In this way, the second water inlet channel 62, the second water outlet channel 102 and the third negative pressure channel 111 can be connected to the first water inlet channel 101, the first water outlet channel and the first negative pressure channel 103 respectively through connecting pipes (such as hoses).

[0024] The vacuum suction cup 11 is fixed to the upper end surface of the cold water pan by bolts, and the bottom end surface and the cooling groove form a cooling cavity; the cooling water can enter the cooling groove through the second water inlet channel 62, the connecting pipe, and the first water inlet channel 101 in sequence, and then can be discharged through the first water outlet channel, the connecting pipe, and the second water outlet channel 102 in sequence. In addition, in order to achieve a certain sealing performance, a first sealing groove 104 (outward) and a second sealing groove 105 (inward) are provided in the middle of the upper end surface of the cold water pan, a first sealing ring 13 is provided in the first sealing groove 104, and a second sealing ring 14 is nested in the second sealing groove 105, and the lower end surface of the vacuum suction cup 11 is in close contact with the first sealing ring 13 and the second sealing ring 14.

[0025] A negative pressure groove is disposed on the upper end surface of the vacuum suction cup 11 . A second negative pressure channel 61 connected with the second channel is axially penetrated through the vacuum suction cup 11 . The second negative pressure channel 61 is located on the central axis of the vacuum suction cup 11 .

[0026] The ceramic disk 12 is tightly attached to the upper end surface of the vacuum suction cup 11, and the bottom end surface and the negative pressure groove form a negative pressure cavity; in this way, the negative pressure source forms a negative pressure in the negative pressure cavity through the second negative pressure channel 61, the connecting pipe, the first negative pressure channel 103, and the third negative pressure channel 111, and the ceramic disk 12 is tightly adsorbed and fixed to the upper end surface of the vacuum suction cup 11. In addition, in order to achieve a certain sealing performance, the upper end surface of the vacuum suction cup 11 is provided with a third sealing groove 112, and a third sealing ring 15 is nested in the third sealing groove 112, and the lower end surface of the ceramic disk 12 is in close contact with the third sealing ring 15.

[0027] Of course, the above are only typical examples of the present invention. In addition, the present invention may also have many other specific implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A polishing bearing platform based on vacuum adsorption and water cooling cycle, characterized in that it includes: a rotating spindle (7); A cold water pan fixed to the upper end of the rotating main shaft (7), the upper end surface of the cold water pan being provided with a cooling groove, the cold water pan being provided with a first negative pressure channel (103) penetrating the axial direction, and a first water inlet channel (101) and a first water outlet channel communicating with the cooling groove; A vacuum suction cup (11) is fixed to the upper end surface of the cold water pan, and the bottom end surface and the cooling groove form a cooling cavity; the upper end surface of the vacuum suction cup (11) is provided with a negative pressure groove, and the vacuum suction cup (11) is axially penetrated with a second negative pressure channel (61) connected with the second channel; A ceramic plate (12) is closely attached to the upper end surface of the vacuum suction cup (11), and the bottom end surface and the negative pressure groove form a negative pressure cavity; A rotary joint (6) is mounted on the rotating main shaft (7) and is provided with a second water inlet channel (62), a second water outlet channel (102) and a third negative pressure channel (111); the second water inlet channel (62), the second water outlet channel (102) and the third negative pressure channel (111) are respectively connected to the first water inlet channel (101), the first water outlet channel and the first negative pressure channel (103) through connecting pipes; And a driving assembly, used for driving the rotating main shaft (7) to rotate.

2. A polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 1, characterized in that: A first channel (71) is axially penetrated through the middle of the rotating main shaft (7); The rotary joint (6) is installed at the lower end of the rotating main shaft (7), and the second water inlet channel (62), the second water outlet channel (102) and the third negative pressure channel (111) are all connected to the first channel (71); The bottom of the cold water pan has a mounting groove, and the upper end of the rotating main shaft (7) is sealingly sleeved in the mounting groove; the lower ends of the first negative pressure channel (103), the first water inlet channel (101), and the first water outlet channel are all connected to the mounting groove.

3. A polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 2, characterized in that: The first negative pressure channel (103) is located on the central axis of the cold water pan, and the second negative pressure channel (61) is located on the central axis of the vacuum suction cup (11).

4. A polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 3, characterized in that: A first sealing groove (104) is provided in the middle of the upper end surface of the cold water pan, a first sealing ring (13) is provided in the first sealing groove (104), and the lower end surface of the vacuum suction cup (11) is in close contact with the first sealing ring (13).

5. A polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 1, characterized in that: The upper end surface of the cold water pan is provided with a second sealing groove (105), a second sealing ring (14) is nested in the second sealing groove (105), and the lower end surface of the vacuum suction cup (11) is in close contact with the second sealing ring (14).

6. A polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 1, characterized in that: The upper end surface of the vacuum suction cup (11) is provided with a third sealing groove (112), a third sealing ring (15) is nested in the third sealing groove (112), and the lower end surface of the ceramic disc (12) is in close contact with the third sealing ring (15).

7. A polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 1, characterized in that: The driving assembly comprises a driving motor (2), a motor seat, a driving wheel (3), a belt (4) and a driven wheel (5); the driven wheel (5) is fixedly sleeved on a rotating main shaft (7), the driving motor (2) is mounted on the motor seat, the driving wheel (3) is mounted on the output end of the driving motor (2), and the belt (4) is sleeved on the driving wheel (3) and the driven wheel (5).

8. The polishing bearing platform based on vacuum adsorption and water cooling cycle as claimed in claim 1, characterized in that: The outer ring of the cold water tray is installed with a bearing assembly (8), and the bearing assembly (8) is equipped with a sealing pressure plate (9).

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