Substrate processing equipment

Abstract

To provide a substrate treatment apparatus that can treat a substrate, while reducing deflection of the substrate caused by loads of treatment applied to the substrate such as a wafer.SOLUTION: A substrate treatment apparatus comprises: a plurality of rollers 11A-11D arrayed around a reference center point CP and arranged to contact a peripheral edge part of a substrate W; a pressing member 21A that presses a treatment tool 3 against an outer periphery part of a surface of the substrate W; and an actuator 22A that applies pressing force to the pressing member 21A. Two rollers 11A and 11B of the plurality of rollers 11A-11D are arranged adjacent to the pressing member 21A and at both sides of the pressing member 21A.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a substrate processing apparatus for processing a substrate such as a wafer, and more particularly to a substrate processing apparatus that presses a processing tool against the surface of a substrate while holding the peripheral portion of the substrate with a rotating roller to process the surface of the substrate.

Background Art

[0002] In recent years, devices such as memory circuits, logic circuits, and image sensors (e.g., CMOS sensors) have been becoming more highly integrated. In the process of forming these devices, foreign substances such as fine particles and dust may adhere to the devices. The foreign substances adhering to the devices may cause short circuits between wirings and circuit malfunctions. Therefore, in order to improve the reliability of the devices, it is necessary to clean the wafer on which the devices are formed to remove the foreign substances on the wafer.

[0003] Foreign substances such as the above-mentioned fine particles and dust may also adhere to the back surface (non-device surface) of the wafer. When such foreign substances adhere to the back surface of the wafer, the wafer is separated from the stage reference surface of the exposure apparatus, so that the wafer surface is inclined with respect to the stage reference surface, and as a result, pattern misalignment and focus distance misalignment occur. In order to prevent such problems, it is necessary to remove the foreign substances adhering to the back surface of the wafer.

[0004] Therefore, as shown in Figures 12 and 13, a substrate processing apparatus is used that polishes the back surface of the wafer with polishing tape. Figure 12 is a top view of a conventional substrate processing apparatus, and Figure 13 is a side view of the conventional substrate processing apparatus shown in Figure 12. The substrate processing apparatus rotates the wafer W by holding the peripheral edge of the wafer W with a plurality of rollers 500, and the rollers 500 themselves rotate. The polishing tape 502 is placed on the back side of the wafer W. A plurality of pressing members 505 are arranged in the diametrical direction of the wafer W, and the back surface of the wafer W is polished by pressing the polishing tape 502 against the back surface of the wafer W with these pressing members 505. The polishing tape 502 pressed against the back surface of the wafer W can remove foreign matter from the back surface of the wafer W. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-77003 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The outer periphery of the wafer W has a larger surface area to be polished compared to the center of the wafer W. Therefore, in order to achieve a uniform polishing rate across the entire back surface of the wafer W, it is necessary to increase the polishing load applied to the outer periphery of the wafer W from the outer pressing member 505. However, as shown in Figure 14, when the polishing tape 502 is pressed against the outer periphery of the wafer W with a large polishing load by the pressing member 505, the wafer W bends upward. Because the wafer W bends in an arc shape, the polishing tape 502 is not pressed uniformly, resulting in an uneven polishing rate on the outer periphery of the wafer W.

[0007] One solution to reduce this wafer W deflection is to lower the polishing load of the outer pressing member 505. However, if the polishing load of the outer pressing member 505 is reduced, the polishing rate of the inner circumference of the wafer W must also be reduced in order to make the polishing rate uniform across the entire back surface of the wafer W. As a result, the polishing rate of the entire back surface of the wafer W decreases, and the polishing time required to achieve the target polishing amount increases.

[0008] Therefore, in order to prevent upward bending of the wafer W, a configuration has been proposed in which a Bernoulli chuck 508 is placed on the back side of the wafer W, as shown in Figures 15 and 16. The Bernoulli chuck 508 is configured to generate an attractive force by releasing a fluid, thereby pulling the back side of the wafer W downward. It is expected that such a Bernoulli chuck 508 will prevent upward bending of the wafer W.

[0009] However, since the Bernoulli chuck 508 is located some distance from the polishing point of the wafer W, upward deflection of the wafer W still occurs, as shown in Figure 17. One solution would be to bring the Bernoulli chuck 508 closer to the polishing point of the wafer W, but due to the presence of the rotating roller 500 and its drive mechanism, it is structurally difficult to bring the Bernoulli chuck 508 closer to the polishing point of the wafer W.

[0010] Miniaturizing the Bernoulli chuck 508 would allow it to be brought closer to the polishing point on the wafer W. However, as the Bernoulli chuck 508 becomes smaller, the suction force it generates also decreases, making it unable to support the polishing load. As a result, the back surface of the wafer W moves away from the Bernoulli chuck 508, and the Bernoulli chuck 508 becomes unable to perform its function.

[0011] Therefore, the present invention provides a substrate processing apparatus that can process a substrate, such as a wafer, while reducing the deflection of the substrate caused by the processing load applied to the substrate. [Means for solving the problem]

[0012] In one embodiment, a substrate processing apparatus is provided, comprising a plurality of rollers arranged around a reference center point and positioned to contact the peripheral edge of the substrate, a pressing member that presses a processing tool against the outer periphery of the surface of the substrate, and an actuator that applies a pressing force to the pressing member, wherein two of the plurality of rollers are adjacent to the pressing member and positioned on both sides of the pressing member.

[0013] In one embodiment, if a reference perpendicular is defined as a line perpendicular to the reference center line extending from the reference center point to the center of the pressing member, and passing through the center of the pressing member, then the axes of the two rollers lie on the reference perpendicular or are located radially outward from the reference perpendicular. In one embodiment, the substrate processing apparatus further comprises a Bernoulli chuck that supports the surface of the substrate in a non-contact manner via a fluid, wherein the central angle between the line extending from the reference center point to the respective axes of the two rollers and the reference center line is smaller than the central angle between the line extending from the reference center point to the center of the Bernoulli chuck and the reference center line. In one embodiment, the two rollers have a different shape from the other rollers among the plurality of rollers. In one embodiment, each of the two rollers has a tapered surface in the shape of an inverted frustocone and is configured to apply a reaction force to the peripheral edge of the substrate in response to the pressing force. In one embodiment, the plurality of rollers have the same shape and are configured to hold the peripheral edge of the substrate. [Effects of the Invention]

[0014] The two rollers arranged on both sides of the pressing member can support the pressing force applied from the pressing member to the outer peripheral portion of the substrate, and can significantly reduce the upward deflection of the substrate. As a result, the processing head can uniformly apply the processing tool to the outer peripheral portion of the substrate with the intended pressing force, and can achieve the target removal rate. Furthermore, a uniform removal rate can be achieved over the entire polished surface of the substrate.

Brief Description of the Drawings

[0015] [Figure 1] It is a side view showing an embodiment of a substrate processing apparatus. [Figure 2] It is a top view of the substrate processing apparatus shown in FIG. 1. [Figure 3] It is a side view showing a roller. [Figure 4] It is a cross-sectional view showing an embodiment of a Bernoulli chuck. [Figure 5] It is a view showing the positional relationship between the rollers arranged on both sides of the pressing member and the Bernoulli chuck located at the position closest to these rollers. [Figure 6] It is a side view showing another embodiment of a substrate processing apparatus. [Figure 7] It is a top view of the substrate processing apparatus shown in FIG. 6. [Figure 8] It is a side view showing a second roller in contact with the peripheral portion of the substrate. [Figure 9] It is a side view showing still another embodiment of a substrate processing apparatus. [Figure 10] It is a side view showing still another embodiment of a substrate processing apparatus. [Figure 11] It is a top view of the substrate processing apparatus shown in FIG. 10. [Figure 12] It is a top view showing an example of a conventional substrate processing apparatus. [Figure 13] It is a side view of the conventional substrate processing apparatus shown in FIG. 12. [Figure 14] It is a side view for explaining the state where the substrate deflects upward. [Figure 15]This is a top view showing another example of a conventional substrate processing apparatus. [Figure 16] Figure 14 is a side view of a conventional substrate processing device. [Figure 17] This is a side view illustrating how the circuit board bends upward. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a side view showing one embodiment of a substrate processing apparatus, and Figure 2 is a top view of the substrate processing apparatus shown in Figure 1. The substrate processing apparatus shown in Figure 1 includes a substrate holding unit 10 that holds a substrate W and rotates the substrate W about a reference center point CP, a plurality of processing heads 20A to 20D that process (polish) the first surface 2a of the substrate W held by the substrate holding unit 10 by bringing a polishing tape 3, which is a processing tool, into contact with the first surface 2a of the substrate W held by the substrate holding unit 10, and a polishing tape supply mechanism 30 that supplies the polishing tape 3 to the processing heads 20A to 20D and collects the polishing tape 3 from the processing heads 20A to 20D. The processing heads 20A to 20D are examples of processing heads that process the surface of the substrate W.

[0017] In this embodiment, the first surface 2a of the substrate W is the back surface of the substrate W on which no devices are formed or on which no devices are planned to be formed, i.e., the non-device surface. The second surface 2b of the substrate W, opposite to the first surface 2a, is the surface on which devices are formed or on which devices are planned to be formed, i.e., the device surface. In this embodiment, the substrate W is horizontally supported by the substrate holder 10 with its first surface 2a facing downwards.

[0018] The substrate holding section 10 includes a plurality of rollers 11A to 11D that can contact the peripheral edge 2c of the substrate W, and a plurality of roller rotating devices 12 for rotating each of the rollers 11A to 11D. The plurality of rollers 11A to 11D are each connected to the corresponding roller rotating device 12 via a plurality of rotating shafts 14 (only two roller rotating devices 12 and two rotating shafts 14 are shown in Figure 1). The plurality of rollers 11A to 11D are arranged around a reference center point CP. The roller rotating devices 12 have electric motors such as servo motors, and the plurality of roller rotating devices 12 are configured to rotate the plurality of rollers 11A to 11D at the same speed in synchronization. In one embodiment, a single roller rotating device may transmit torque to the plurality of rollers 11A to 11D via a synchronization belt or the like, causing these rollers 11A to 11D to rotate at the same speed. In this embodiment, four rollers 11A to 11D are provided, but five or more rollers may be provided.

[0019] Since rollers 11A to 11D have the same shape, roller 11A will be described below with reference to Figure 3. Figure 3 is a side view showing roller 11A. Roller 11A has a substrate holding surface 15 that can contact the peripheral edge 2c of the substrate W. The peripheral edge 2c of the substrate W is the outermost annular curved surface of the substrate W and is connected to both the outer periphery of the first surface 2a and the outer periphery of the second surface 2b. The peripheral edge 2c is sometimes also called the bevel. The substrate holding surface 15 has a cylindrical shape that is constricted inward. A substrate holding surface 15 with such a shape can limit the tilt of the substrate W during processing, as well as the height and vertical movement of the substrate W.

[0020] As shown in Figures 1 and 2, the multiple processing heads 20A to 20D are positioned below the substrate W held by the substrate holder 10. These processing heads 20A to 20D are arranged in the diametrical direction of the substrate W. In this embodiment, four processing heads 20A to 20D are provided, but the number of processing heads is not limited to this embodiment.

[0021] The processing head 20A includes a pressing member 21A that presses the polishing tape 3 against the first surface 2a of the substrate W, and an actuator 22A that applies a pressing force to the pressing member 21A. The actuator 22A pushes the pressing member 21A upward, and the pressing member 21A presses the polishing tape 3 against the first surface 2a of the substrate W from its back side, thereby processing (polishing) the first surface 2a of the substrate W.

[0022] Processing heads 20B to 20D have the same configuration as processing head 20A. That is, processing heads 20B to 20D are each equipped with pressing members 21B to 21D that press the polishing tape 3 against the first surface 2a of the substrate W, and actuators 22B to 22D that apply pressing force to the pressing member 21A.

[0023] The abrasive tape supply mechanism 30 includes a tape unwinding reel 31 to which one end of the abrasive tape 3 is connected, a tape taking reel 32 to which the other end of the abrasive tape 3 is connected, and a plurality of guide rollers 33 that guide the direction of travel of the abrasive tape 3. The abrasive tape 3 progresses from the tape unwinding reel 31, through processing heads 20A to 20D, to the tape taking reel 32.

[0024] The tape unwinding reel 31 and the tape taking reel 32 are each connected to reel motors (not shown). These reel motors apply torque to the tape unwinding reel 31 and the tape taking reel 32 in opposite directions, thereby generating tension in the polishing tape 3. The torque applied to the tape taking reel 32 is greater than the torque applied to the tape unwinding reel 31. During polishing of the substrate W, as the tape taking reel 32 is rotated by the reel motors, tension is applied to the polishing tape 3 as it moves from the tape unwinding reel 31 through the processing heads 20A to 20D to the tape taking reel 32.

[0025] In one embodiment, a tape feeding device may be provided for feeding the abrasive tape 3 in its longitudinal direction, separate from the tape unwinding reel 31, the tape taking reel 32, and the reel motor. In yet another embodiment, the positions of the tape unwinding reel 31 and the tape taking reel 32 may be reversed.

[0026] The substrate processing apparatus further comprises a plurality of Bernoulli chucks 50 that non-contact support the first surface (bottom surface) 2a of the substrate W via a fluid. These Bernoulli chucks 50 are positioned below the first surface 2a of the substrate W held by the substrate holding unit 10, and are positioned opposite the first surface 2a, similar to the processing heads 20A to 20D. These Bernoulli chucks 50 are positioned adjacent to the pressing members 21A to 21D of the plurality of processing heads 20A to 20D. In the example shown in Figure 2, six Bernoulli chucks 50 are positioned on both sides of the polishing tape 3, but the number and arrangement of the Bernoulli chucks 50 are not limited to the example in Figure 2.

[0027] Figure 4 is a cross-sectional view showing one embodiment of the Bernoulli chuck 50. As shown in Figure 4, each Bernoulli chuck 50 has a suction surface 50a facing the first surface 2a of the substrate W held by the substrate holding portion 10. A fluid supply line 53 is connected to the Bernoulli chuck 50 to supply fluid (for example, a gas such as dry air or an inert gas, or a liquid such as pure water) around the suction surface 50a. The fluid flows through the fluid supply line 53 and is discharged outward from the outer periphery of the suction surface 50a, thereby creating a negative pressure in the space between the suction surface 50a and the first surface 2a of the substrate W. This allows the Bernoulli chuck 50 to suck the first surface 2a of the substrate W. Because a fluid flow is formed in the gap between the outer periphery of the suction surface 50a and the first surface 2a of the substrate W, the Bernoulli chuck 50 does not come into contact with the substrate W. Therefore, while the Bernoulli chuck 50 supports the first surface 2a of the substrate W without contact, the rollers 11A to 11D of the substrate holding section 10 can rotate the substrate W.

[0028] As shown in Figures 1 and 2, when the polishing tape 31 is pressed against the first surface 2a of the substrate W to polish the first surface 2a of the substrate W, the pressing members 21A to 21D apply an upward processing load to the substrate W. In this embodiment, the substrate W is subjected to a downward suction force by the Bernoulli chuck 50. This downward suction force counteracts the upward processing load applied to the substrate W. Therefore, the Bernoulli chuck 50 can reduce the bending of the substrate W.

[0029] However, the outermost pressing member 21A is positioned radially outward from the Bernoulli chuck 50, and in order to make the removal rate of the substrate W uniform across the entire first surface 2a, the outermost pressing member 21A presses the polishing tape 3 against the substrate W with a greater pressing force than the other pressing members 21B to 21D. Therefore, the outer periphery of the substrate W is prone to bending due to the pressing force applied by the outermost pressing member 21A.

[0030] Therefore, in order to receive the pressing force applied by the pressing member 21A, two of the rollers 11A to 11D, namely rollers 11A and 11B, are positioned adjacent to the pressing member 21A and on both sides of the pressing member 21A. Both sides of the pressing member 21A mean both sides of the pressing member 21A in the circumferential direction of the substrate W. In particular, in this embodiment, as shown in Figure 2, the axes CA of the two rollers 11A and 11B are either on the reference perpendicular L2 or located radially outward from the reference perpendicular L2. The reference perpendicular L2 is perpendicular to the reference center line L1 extending from the reference center point CP to the center C1 of the pressing member 21A, and passes through the center C1 of the pressing member 21A. In the embodiment shown in Figure 2, the axes CA of the two rollers 11A and 11B are located radially outward from the reference perpendicular L2.

[0031] The two rollers 11A and 11B, arranged in this manner, can support the pressing force applied from the pressing member 21A of the processing head 20A to the outer periphery of the first surface 2a of the substrate W, and can significantly reduce the upward deflection of the substrate W. As a result, the processing head 20A can uniformly apply the polishing tape 3 to the outer periphery of the first surface 2a of the substrate W with the intended pressing force, and can achieve the target removal rate. Furthermore, a uniform removal rate can be achieved across the entire first surface 2a of the substrate W.

[0032] Figure 5 shows the positional relationship between the rollers 11A and 11B positioned on both sides of the pressing member 21A and the Bernoulli chuck 50 located closest to these rollers 11A and 11B. For the sake of clarity, the pressing members 21B to 21D are not shown in Figure 5.

[0033] As shown in Figure 5, the central angle α1 between the line L3 extending from the reference center point CP to the axis CA of roller 11A and the reference center line L1 is smaller than the central angle β1 between the line L4 extending from the reference center point CP to the center C2 of the Bernoulli chuck 50 closest to this roller 11A and the reference center line L1. Similarly, the central angle α2 between the line L5 extending from the reference center point CP to the axis CA of roller 11B and the reference center line L1 is smaller than the central angle β2 between the line L6 extending from the reference center point CP to the center C3 of the Bernoulli chuck 50 closest to this roller 11B and the reference center line L1.

[0034] Since the two rollers 11A and 11B, arranged in this manner, are closer to the pressing member 21A than the Bernoulli chuck 50, they can work together with the Bernoulli chuck 50 to significantly reduce the upward deflection of the substrate W.

[0035] Figure 6 is a side view showing another embodiment of the substrate processing apparatus, and Figure 7 is a top view of the substrate processing apparatus shown in Figure 6. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to Figures 1 to 5, so redundant descriptions are omitted. As shown in Figures 6 and 7, in this embodiment, in addition to the rollers 11A to 11D, two rollers 60A and 60B that contact the peripheral edge 2c of the substrate W are provided. In the following description, the rollers 11A to 11D will be referred to as the first rollers 11A to 11D, and the two rollers 60A and 60B will be referred to as the second rollers 60A and 60B. The first rollers 11A to 11D and the second rollers 60A and 60B are arranged around a reference center point CP.

[0036] The first rollers 11A to 11D are provided for the purpose of applying torque to the substrate W and rotating the substrate W. The first rollers 11A to 11D are arranged at equal intervals around a reference center point CP. In this embodiment, four first rollers 11A to 11D are provided, but five or more first rollers may be provided.

[0037] The two second rollers 60A and 60B are provided to support the pressing force applied to the substrate W from the pressing member 21A and to reduce the deflection of the substrate W. The two second rollers 60A and 60B have a different shape from the first rollers 11A to 11D. The second rollers 60A and 60B are adjacent to the pressing member 21A and are positioned on both sides of the pressing member 21A. The arrangement of the second rollers 60A and 60B is the same as the arrangement of the two rollers 11A and 11B described with reference to Figures 2 and 5, so a redundant explanation will be omitted.

[0038] The two second rollers 60A and 60B are each connected to two corresponding second roller rotating devices 63 via two rotating shafts 64 (only one second roller rotating device 63 and one rotating shaft 64 are shown in Figure 6). The second roller rotating device 63 operates in synchronous motion with the first roller rotating device 12 that rotates the first rollers 11A to 11D, and rotates the second rollers 60A and 60B at a rotational speed such that the peripheral speed of the second rollers 60A and 60B is the same as the peripheral speed of the first rollers 11A to 11D. By rotating the second rollers 60A and 60B using the second roller rotating device 63, friction between the second rollers 60A and 60B and the peripheral edge of the substrate W is reduced, and the generation of particles caused by friction is also prevented. Depending on the material of the second rollers 60A and 60B, the second rollers 60A and 60B may be configured to rotate freely without the provision of the second roller rotating device 63. In this case, the second rollers 60A and 60B are rotated by contact with the peripheral edge 2c of the substrate W.

[0039] Since the second rollers 60A and 60B have the same shape, the second roller 60A will be described below with reference to Figure 8. Figure 8 is a side view showing the second roller 60A in contact with the peripheral edge 2c of the substrate W. As shown in Figure 8, each second roller 60A has a tapered surface 61 in the shape of an inverted frustocone, and is configured to apply a reaction force to the peripheral edge 2c of the substrate W in response to the pressing force generated by the processing head 20A. In the example shown in Figure 8, the tapered surface 61 of the second roller 60A is generally oriented downwards, and the second roller 60A applies a downward reaction force to the peripheral edge 2c of the substrate W.

[0040] The second rollers 60A and 60B, arranged in this manner, can support the pressing force applied from the pressing member 21A of the processing head 20A to the outer periphery of the first surface 2a of the substrate W, and can significantly reduce the upward deflection of the substrate W. As a result, the processing head 20A can uniformly apply the polishing tape 3 to the outer periphery of the first surface 2a of the substrate W with the intended pressing force, and can achieve the target removal rate. Furthermore, a uniform removal rate can be achieved across the entire first surface 2a of the substrate W.

[0041] In addition to the two second rollers 60A and 60B, at least one more second roller may be provided between the first rollers 11A to 11D. For example, as shown in Figure 9, at least one second roller (indicated by reference numerals 60A to 60F) may be placed between two adjacent first rollers 11A to 11D. By arranging the first rollers 11A to 11D and the second rollers 60A to 60F alternately in this way, the suction force required for the Bernoulli chuck 50 can be reduced, and as a result, the amount of fluid supplied to the Bernoulli chuck 50 can be reduced.

[0042] The substrate processing apparatus of the embodiments described so far is configured to rotate the rollers 11A to 11D (and the second rollers 60A to 60F) around their axes, but the present invention can also be applied to a substrate processing apparatus that performs orbital motion on the rollers 11A to 11D (and the second rollers 60A to 60F). Specifically, as shown in Figures 10 and 11, the rollers 11A to 11D (and the second rollers 60A to 60F) may be connected to the corresponding roller rotating device 12 via an eccentric shaft 70. The rollers 11A to 11D (and the second rollers 60A to 60F) are each fixed to the corresponding eccentric shaft 70. With this configuration, the rollers 11A to 11D (and the second rollers 60A to 60F) rotate around their own centers while tracing circular orbits, and the substrate W also rotates around its own centers while tracing circular orbits. The embodiments described with reference to Figures 1 to 8 can similarly be applied to the embodiments shown in Figures 10 and 11.

[0043] In the embodiments described above, abrasive tape is used as the processing tool, but instead of abrasive tape, a grinding wheel, cleaning tape, nonwoven fabric tape, or cleaning pad may be used.

[0044] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of symbols]

[0045] W board 2a First face 2b Second face 2c Peripheral area 3. Abrasive tape (processing tool) 10 Board holding part 11A~11D Rollers 12 Roller Rotating Device 14 Rotation axis 15 Board holding surface 20A~20D Processing Head 21A~21D Pressing Member 22A~22D Actuators 30. Polishing tape supply mechanism 31 Tape unwinding reel 32 Tape winding reels 33 Guide rollers 50 Bernoullichak 50a suction surface 53 Fluid supply line 60A~60F Second Roller 61 Tapered surface 63. Second Roller Rotating Device 64 rotational axes 70 Eccentric shaft

Claims

1. Multiple rollers arranged around a reference center point and positioned to contact the periphery of the substrate, Multiple pressing members that press the processing tool against the surface of the substrate, The system includes actuators that apply pressing force to the plurality of pressing members, The plurality of pressing members include an outer pressing member that presses the processing tool against the outer periphery of the surface of the substrate, A portion of the outer pressing member protrudes outward from the peripheral edge of the substrate. Two of the aforementioned rollers are adjacent to the outer pressing member and are positioned on both sides of the outer pressing member. A substrate processing apparatus in which, if a reference perpendicular line is defined as a line perpendicular to the reference center line extending from the reference center point to the center of the outer pressing member and passing through the center of the outer pressing member, the axes of the two rollers lie on the reference perpendicular line or are located radially outward from the reference perpendicular line.

2. Multiple rollers arranged around a reference center point and positioned to contact the periphery of the substrate, Multiple pressing members that press the processing tool against the surface of the substrate, An actuator that applies pressing force to the plurality of pressing members, The substrate is equipped with a Bernoulli chuck that supports the surface of the substrate in a non-contact state via a fluid, The plurality of pressing members include an outer pressing member that presses the processing tool against the outer periphery of the surface of the substrate, A portion of the outer pressing member protrudes outward from the peripheral edge of the substrate. Two of the aforementioned rollers are adjacent to the outer pressing member and are positioned on both sides of the outer pressing member. A substrate processing apparatus, wherein the central angle between the line extending from the reference center point to the respective axes of the two rollers and the reference center line extending from the reference center point to the center of the outer pressing member is smaller than the central angle between the line extending from the reference center point to the center of the Bernoulli chuck and the reference center line.

3. Multiple rollers arranged around a reference center point and positioned to contact the periphery of the substrate, Multiple pressing members that press the processing tool against the surface of the substrate, The system includes actuators that apply pressing force to the plurality of pressing members, The plurality of pressing members include an outer pressing member that presses the processing tool against the outer periphery of the surface of the substrate, A portion of the outer pressing member protrudes outward from the peripheral edge of the substrate. Two of the aforementioned rollers are adjacent to the outer pressing member and are positioned on both sides of the outer pressing member. A substrate processing apparatus wherein the two rollers have a different shape from the other rollers among the plurality of rollers.

4. The substrate processing apparatus according to claim 3, wherein each of the two rollers has a tapered surface in the shape of an inverted frustocone and is configured to apply a reaction force to the peripheral edge of the substrate in response to the pressing force.

5. The substrate processing apparatus according to claim 1 or 2, wherein the plurality of rollers have the same shape and are configured to hold the peripheral edge of the substrate.

6. Multiple rollers arranged around a reference center point and positioned to contact the periphery of the substrate, Multiple pressing members that press the processing tool against the surface of the substrate, The system includes actuators that apply pressing force to the plurality of pressing members, The plurality of pressing members include an outer pressing member that presses the processing tool against the outer periphery of the surface of the substrate, A portion of the outer pressing member protrudes outward from the peripheral edge of the substrate. Two of the aforementioned rollers are adjacent to the outer pressing member and are positioned on both sides of the outer pressing member. A substrate processing apparatus wherein the two rollers are positioned closer to the outer pressing member than the positions of the two rollers if the plurality of rollers, including the two rollers, were arranged at equal intervals around the reference center point.

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