Polishing head system, polishing apparatus, and polishing method

Abstract

This invention provides a polishing head system that can prevent particles caused by the polishing fluid from adhering to the gaps in the polishing head. [Solution] The polishing head system 10 includes a polishing head 11 for pressing the substrate W against the polishing pad 2, a plurality of retainer rollers 25 arranged to surround the polishing head 11, and a retainer roller pressing mechanism 56 for pressing the plurality of retainer rollers 25 against the polishing pad 11.

Description

Technical Field

[0001] The present invention relates to a polishing head system and a polishing apparatus used for polishing a substrate such as a wafer. The present invention also relates to a polishing method for polishing a substrate such as a wafer.

Background Art

[0002] Chemical mechanical polishing (CMP) is a technique for polishing the surface of a substrate by supplying a polishing liquid onto a polishing pad, pressing a substrate such as a wafer against the polishing pad, and causing the substrate to slide in contact with the polishing pad in the presence of the polishing liquid (for example, a slurry containing abrasive grains). The surface of the substrate is planarized by the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad.

[0003] FIG. 13 is a cross-sectional view schematically showing an example of a polishing head 100. As shown in FIG. 13, the polishing head 100 includes an elastic film 105 for pressing a substrate W against a polishing pad 102. A pressure chamber 110 is formed inside the elastic film 105. When pressurized gas (for example, pressurized air) is supplied into the pressure chamber 110, the elastic film 105 receiving the pressure in the pressure chamber 110 presses the substrate W against the polishing pad 102. Therefore, the substrate W is slid in contact with the polishing pad 102 in a state where the polishing liquid is present on the polishing pad 102.

[0004] An annular retainer ring 115, which is an annular structure arranged to surround the substrate W, is attached to the outside of the elastic film 105 of the polishing head 100. This retainer ring 115 has a function of preventing the substrate W from jumping out of the polishing head 100 during polishing of the substrate W. During polishing of the substrate W, the retainer ring 115 presses the polishing pad 102 outside the substrate W while rotating.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, since the retainer ring 115 covers the entire perimeter of the substrate W, polishing fluid can seep into the gap between the elastic film 105 and the retainer ring 115 during polishing of the substrate W, and components of the polishing fluid may solidify. Such particles caused by the polishing fluid can cause scratches on the surface of the substrate W. However, it is difficult to completely remove the particles present in the gap between the elastic film 105 and the retainer ring 115 even by supplying cleaning fluid to this gap. Furthermore, cleaning the retainer ring 115 by removing it from the polishing head 100 is time-consuming and laborious.

[0007] Therefore, the present invention provides a polishing head system and polishing apparatus that can prevent polishing liquid from entering the gaps of the polishing head and prevent the generation of particles caused by the polishing liquid. Furthermore, the present invention provides a polishing method for polishing substrates such as wafers using such a polishing head system. [Means for solving the problem]

[0008] In one embodiment, a polishing head system is provided, comprising a polishing head for pressing a substrate against a polishing pad, a plurality of retainer rollers arranged to surround the polishing head, and a retainer roller pressing mechanism for pressing the plurality of retainer rollers against the polishing pad. In one embodiment, the polishing head system further comprises a retainer roller rotation mechanism that rotates at least one of the plurality of retainer rollers. In one embodiment, the retainer roller pressing mechanism is a plurality of retainer roller pressing mechanisms that press the plurality of retainer rollers against the polishing pad, respectively. In one embodiment, the polishing head system further comprises a retainer roller moving mechanism that moves at least one of the plurality of retainer rollers in the radial direction of the polishing head. In one embodiment, the polishing head includes an elastic membrane that forms a pressure chamber for pressing the substrate against the polishing pad, and the polishing head system includes a pressure regulator for adjusting the pressure in the pressure chamber.

[0009] In one embodiment, a polishing apparatus is provided that includes the polishing head system, a polishing table that supports the polishing pad, and a table motor that rotates the polishing table. In one embodiment, the plurality of retainer rollers include a plurality of downstream retainer rollers arranged downstream of the polishing head in the direction of travel of the polishing pad, and at least one upstream retainer roller arranged upstream of the polishing head in the direction of travel. In one embodiment, the polishing apparatus further comprises a polishing head moving motor for oscillating the polishing head between a first position and a second position, wherein the plurality of downstream retainer rollers include a first downstream retainer roller and a second downstream retainer roller, the first downstream retainer roller being positioned downstream of the polishing head in the direction of travel of the polishing pad when the polishing head is in the first position, and the second downstream retainer roller being positioned downstream of the polishing head in the direction of travel when the polishing head is in the second position. In one embodiment, the polishing apparatus further comprises a cleaning device for cleaning the polishing head and the plurality of retainer rollers.

[0010] In one embodiment, a polishing apparatus is provided comprising the polishing head system, a polishing table supporting the polishing pad, a table motor for rotating the polishing table, a notch detector for detecting a notch formed on the periphery of the substrate, and an operation control unit for controlling the operation of the retainer roller rotation mechanism, wherein the operation control unit determines the relative circumferential position of the notch with respect to a reference position of the polishing head based on the notch detection signal, and based on the relative circumferential position of the notch with respect to the reference position of the polishing head, it commands the retainer roller rotation mechanism to rotate the plurality of retainer rollers so that the position of the notch in the circumferential direction of the polishing head coincides with the reference position. In one embodiment, a polishing apparatus is provided comprising the polishing head system, a polishing table supporting the polishing pad, a table motor for rotating the polishing table, an operation control unit for controlling the operation of the retainer roller pressing mechanism and the retainer roller moving mechanism, and a film thickness sensor for obtaining the film thickness profile of the substrate, wherein the plurality of retainer rollers include an upstream retainer roller positioned upstream of the polishing head in the direction of travel of the polishing pad, the retainer roller moving mechanism is configured to move the upstream retainer roller in the radial direction, and the operation control unit is configured to give a command to the retainer roller moving mechanism to adjust the position of the upstream retainer roller in the radial direction based on the film thickness profile, and to give a command to the retainer roller pressing mechanism to adjust the pressing force of the upstream retainer roller against the polishing pad. In one embodiment, a polishing apparatus is provided comprising the polishing head system, a polishing table supporting the polishing pad, a table motor for rotating the polishing table, and an operation control unit for controlling the operation of the retainer roller moving mechanism, wherein the plurality of retainer rollers include a plurality of downstream retainer rollers arranged downstream of the polishing head in the direction of travel of the polishing pad, the retainer roller moving mechanism is a plurality of retainer roller moving mechanisms for moving the plurality of downstream retainer rollers in the radial direction, the polishing head system further comprises a load measuring device for measuring the radial load of the substrate applied to the plurality of downstream retainer rollers, and the operation control unit is configured to adjust the positions of the plurality of downstream retainer rollers in the radial direction by issuing commands to the plurality of retainer roller moving mechanisms so that the radial load of the substrate applied to the plurality of downstream retainer rollers is equal, based on the measured value of the radial load of the substrate. In one embodiment, a polishing apparatus is provided comprising the polishing head system, a polishing table supporting the polishing pad, a table motor for rotating the polishing table, a notch detector for detecting a notch formed on the periphery of the substrate, and an operation control unit for controlling the operation of the pressure regulator, wherein the pressure chamber is a plurality of pressure chambers arranged in the circumferential direction, the pressure regulator is a plurality of pressure regulators for adjusting the pressure in the plurality of pressure chambers, and the operation control unit is configured to determine the relative circumferential position of the notch with respect to a reference position of the polishing head based on the detection signal of the notch, and to give commands to the plurality of pressure regulators to adjust the pressure in each of the plurality of pressure chambers based on the relative position of the notch with respect to the reference position of the polishing head.

[0011] In one embodiment, a polishing method is provided in which a polishing table supporting a polishing pad is rotated, a polishing head is used to press the substrate against the polishing pad to polish the substrate, and during the polishing of the substrate, a plurality of retainer rollers arranged to surround the polishing head are pressed against the polishing pad by a retainer roller pressing mechanism. In one embodiment, the polishing method further includes pressing the plurality of retainer rollers against the polishing pad with the retainer roller pressing mechanism, while rotating at least one of the plurality of retainer rollers with a retainer roller rotating mechanism. In one embodiment, pressing the plurality of retainer rollers against the polishing pad by the retainer roller pressing mechanism is equivalent to pressing each of the plurality of retainer rollers against the polishing pad by the plurality of retainer roller pressing mechanisms. In one embodiment, the polishing method further includes moving at least one of the plurality of retainer rollers in the radial direction of the polishing head by a retainer roller moving mechanism. In one embodiment, the polishing head includes an elastic membrane that forms a pressure chamber for pressing the substrate against the polishing pad, and pressing the substrate against the polishing pad by the polishing head is performed by adjusting the pressure in the pressure chamber to press the substrate against the polishing pad with the elastic membrane.

[0012] In one embodiment, the plurality of retainer rollers include a plurality of downstream retainer rollers arranged downstream of the polishing head in the direction of travel of the polishing pad, and at least one upstream retainer roller arranged upstream of the polishing head in the direction of travel. In one embodiment, the polishing method further includes oscillating the polishing head between a first position and a second position while polishing the substrate, wherein the plurality of downstream retainer rollers include a first downstream retainer roller and a second downstream retainer roller, the first downstream retainer roller being positioned downstream of the polishing head in the direction of travel of the polishing pad when the polishing head is in the first position, and the second downstream retainer roller being positioned downstream of the polishing head in the direction of travel when the polishing head is in the second position. In one embodiment, the polishing method further includes cleaning the polishing head and the plurality of retainer rollers with a cleaning device after the substrate has been polished and the substrate has been removed from the polishing device.

[0013] In one embodiment, the polishing method further includes detecting a notch formed on the peripheral edge of the substrate using a notch detector while polishing the substrate, determining the relative circumferential position of the notch with respect to a reference position of the polishing head based on the detection signal of the notch, and rotating the plurality of retainer rollers in the circumferential direction of the polishing head so that the position of the notch coincides with the reference position based on the relative circumferential position of the notch with respect to the reference position of the polishing head. In one embodiment, the plurality of retainer rollers include an upstream retainer roller positioned upstream of the polishing head in the direction of travel of the polishing pad, and the polishing method further includes obtaining a film thickness profile of the substrate using a film thickness sensor while polishing the substrate, and adjusting the position of the upstream retainer roller in the radial direction of the polishing head and the pressing force of the upstream retainer roller against the polishing pad based on the film thickness profile. In one embodiment, the plurality of retainer rollers include a plurality of downstream retainer rollers positioned downstream of the polishing head in the direction of travel of the polishing pad, and the polishing method further includes measuring the radial load of the substrate applied to the plurality of downstream retainer rollers using a load measuring device during polishing of the substrate, and adjusting the positions of the plurality of downstream retainer rollers in the radial direction so that the radial load of the substrate applied to the plurality of downstream retainer rollers is uniform based on the measured value of the radial load of the substrate. In one embodiment, the pressure chamber is a plurality of pressure chambers arranged in the circumferential direction, and further includes detecting a notch formed on the periphery of the substrate by a notch detector during polishing of the substrate, and determining the relative circumferential position of the notch with respect to a reference position of the polishing head based on the detection signal of the notch, and pressing the substrate against the polishing pad with the polishing head by adjusting the pressure in each of the plurality of pressure chambers based on the relative circumferential position of the notch with respect to the reference position of the polishing head, thereby pressing the substrate against the polishing pad with the elastic membrane.

Advantages of the Invention

[0014] Since there is no closed gap in the polishing head in the polishing head system provided with a plurality of retainer rollers, the polishing liquid does not stay in the polishing head. Therefore, generation of particles due to the polishing liquid can be prevented.

Brief Description of the Drawings

[0015] [Figure 1] It is a schematic diagram showing one embodiment of a polishing apparatus. [Figure 2] It is a cross-sectional view showing one embodiment of a polishing head system. [Figure 3] It is a top view of the elastic film shown in FIG. 2. [Figure 4] It is a side view of the polishing head system shown in FIG. 2. [Figure 5] It is a schematic diagram showing one embodiment of a retainer roller actuator. [Figure 6] It is a top view showing the arrangement of a plurality of retainer rollers. [Figure 7] It is a top view showing how the polishing head swings during polishing of the substrate. [Figure 8] It is a cross-sectional view schematically showing the positional relationship between the substrate and the pad rebound due to the pressing force of the retainer roller. [Figure 9] FIG. 9(a) is a top view of a polishing head provided with a conventional retainer ring, and FIG. 9(b) is a cross-sectional view of a portion of the retainer ring located on the downstream side of the polishing head and the substrate in the traveling direction of the polishing pad. [Figure 10] FIG. 10(a) is a top view of the polishing head system according to the present embodiment, and FIG. 10(b) is a cross-sectional view of the downstream-side retainer roller and the substrate arranged on the downstream side of the polishing head in the traveling direction of the polishing pad. [Figure 11] It is a top view for explaining the polishing position and the transfer position of the substrate. [Figure 12] It is a top view showing one embodiment of a cleaning device. [Figure 13] This is a schematic cross-sectional view showing an example of a conventional polishing head. [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 schematic diagram showing one embodiment of the polishing apparatus 1. The polishing apparatus 1 is a device for chemically and mechanically polishing a substrate W such as a wafer. As shown in Figure 1, the polishing apparatus 1 includes a polishing table 3 that supports a polishing pad 2 having a polishing surface 2a, a polishing head system 10 for pressing the substrate W against the polishing surface 2a, and a polishing liquid supply nozzle 8 for supplying a polishing liquid (for example, a slurry containing abrasive particles) to the polishing surface 2a.

[0017] The polishing head system 10 includes a polishing head 11 for pressing the substrate W against the polishing surface 2a, and a plurality of retainer rollers 25 (five in this embodiment) arranged to surround the polishing head 11. The polishing head 11 is configured to hold the substrate W on its lower surface.

[0018] The polishing device 1 further comprises a support shaft 15, a polishing head support arm 14 connected to the upper end of the support shaft 15, and a polishing head shaft 12 rotatably supported at the free end of the polishing head support arm 14. The polishing head 11 is fixed to the lower end of the polishing head shaft 12. A polishing head rotation mechanism 20 for rotating the polishing head 11 and a polishing head lifting mechanism 22 for moving the polishing head 11 up and down are arranged inside the polishing head support arm 14.

[0019] The polishing head rotation mechanism 20 is connected to the polishing head shaft 12 and is configured to rotate the polishing head shaft 12 and the polishing head 11 in the direction indicated by the arrow in Figure 1. The polishing head rotation mechanism 20 includes a motor and the like. The polishing head rotation mechanism 20 is connected to a rotary encoder 21, which acts as a rotation angle detector for detecting the rotation angle of the polishing head 11. This rotary encoder 21 is configured to detect the rotation angle of the polishing head rotation mechanism 20. The rotation angle of the polishing head rotation mechanism 20 matches the rotation angle of the polishing head 11. Therefore, the rotation angle of the rotary motor 20 detected by the rotary encoder 21 corresponds to the rotation angle of the polishing head 11.

[0020] The polishing head lifting mechanism 22 is connected to the polishing head shaft 12 and is configured to move the polishing head shaft 12 up and down relative to the polishing head support arm 14. This up and down movement of the polishing head shaft 12 allows the polishing head 11 to move up and down relative to the polishing head support arm 14 and the polishing table 3, as indicated by the arrows in Figure 1. The polishing head lifting mechanism 22 is configured, for example, by a combination of a ball screw and a servo motor. In Figure 1, the polishing head rotation mechanism 20 and the polishing head lifting mechanism 22 are schematically depicted.

[0021] The polishing device 1 further includes a polishing head moving motor 18 that moves the polishing head 11 in a direction parallel to the polishing surface 2a of the polishing pad 2. In this embodiment, the polishing head moving motor 18 is located within the support shaft 15. The polishing head moving motor 18 is configured to pivot the polishing head support arm 14 around the support shaft 15. By pivoting the polishing head support arm 14, the polishing head 11 and retainer roller 25 connected to the polishing head support arm 14 are moved in a direction parallel to the polishing surface 2a of the polishing pad 2. In one embodiment, the polishing head support arm 14 may be fixed to the support shaft 15, and the polishing head moving motor 18 may be connected to the support shaft 15.

[0022] The polishing apparatus 1 further includes a table motor 6 that rotates the polishing pad 2 and the polishing table 3 around their respective axes. The table motor 6 is located below the polishing table 3, and the polishing table 3 is connected to the table motor 6 via a table shaft 5. The polishing table 3 and the polishing pad 2 are rotated by the table motor 6 around the table shaft 5 in the direction indicated by the arrows in Figure 1. The polishing pad 2 is attached to the upper surface of the polishing table 3. The exposed surface of the polishing pad 2 constitutes the polishing surface 2a for polishing a substrate W such as a wafer.

[0023] The polishing apparatus 1 includes a polishing head system 10, a polishing head rotation mechanism 20, a polishing head lifting mechanism 22, a polishing head moving motor 18, a table motor 6, and an operation control unit 50 that controls the operation of the polishing fluid supply nozzle 8. The polishing head system 10, the polishing head rotation mechanism 20, the rotary encoder 21, the polishing head lifting mechanism 22, the polishing head moving motor 18, the table motor 6, and the polishing fluid supply nozzle 8 are electrically connected to the operation control unit 50. The detected rotation angle of the polishing head rotation mechanism 20 (i.e., the detected rotation angle of the polishing head 11) output from the rotary encoder 21 is sent to the operation control unit 50.

[0024] The operation control unit 50 comprises a storage device 50a in which a program is stored, and an arithmetic unit 50b that performs calculations according to the instructions contained in the program. The operation control unit 50 is composed of at least one computer. The storage device 50a comprises a main memory such as random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) or solid state drive (SSD). Examples of arithmetic units 50b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the operation control unit 50 is not limited to these examples.

[0025] Next, the details of the polishing head system 10 will be described. Figure 2 is a cross-sectional view showing one embodiment of the polishing head system 10. The polishing head 11 comprises a carrier 31 connected to the polishing head shaft 12 and an elastic membrane 34 attached to the lower surface of the carrier 31. In one embodiment, the polishing head 11 may be a carrier (pressing member) without the elastic membrane 34. The lower surface of the elastic membrane 34 constitutes a pressing surface 34a, which is in contact with the upper surface of the substrate W (the surface opposite to the surface to be polished). In this embodiment, a plurality of through holes (not shown) are formed in the pressing surface 34a. In one embodiment, through holes may not be formed in the pressing surface 34a. The pressing surface 34a has substantially the same shape as the upper surface of the substrate W. The pressing surface 34a is substantially the same size as the upper surface of the substrate W, or slightly smaller.

[0026] Figure 3 is a top view of the elastic membrane 34 shown in Figure 2. As shown in Figure 3, the elastic membrane 34 comprises first wall portions 34b, 34c, 34d, and 34e that radially divide the space between the carrier 31 and the elastic membrane 34, and second wall portions 34f and 34g that circumferentially divide the space between the carrier 31 and the elastic membrane 34. The first wall portions 34b to 34e and the second wall portions 34f and 34g are connected to the pressing surface 34a. The first wall portions 34b, 34c, 34d, and 34e extend in the circumferential direction of the polishing head 11, and the second wall portions 34f and 34g extend in the radial direction of the polishing head 11. The first wall portions 34b to 34e are endless walls arranged concentrically. The first wall portion 34e is located radially outward of the first wall portion 34d, the first wall portion 34d is located radially outward of the first wall portion 34c, and the first wall portion 34c is located radially outward of the first wall portion 34b.

[0027] The second wall portions 34f and 34g both pass through the axis EP of the elastic film 34 and intersect each other. The substrate W is held by the polishing head 11 so that its axis coincides with the axis EP of the elastic film 34. In this embodiment, four first wall portions 34b to 34e and two second wall portions 34f and 34g are provided, but the configuration of the elastic film 34 is not limited to this embodiment. In one embodiment, three or fewer or five or more first wall portions may be provided, or one or three or more second wall portions may be provided.

[0028] In this embodiment, the space between the carrier 31 and the elastic membrane 34 is divided radially into four sections by the first wall sections 34b to 34e, and circumferentially into four sections by the second wall sections 34f and 34g. Therefore, 16 pressure chambers C1 to C16 are formed between the carrier 31 and the elastic membrane 34.

[0029] The polishing head system 10 includes a plurality of gas transfer lines F1 to F16 (16 in this embodiment) that communicate with a plurality of pressure chambers C1 to C16, and a plurality of pressure regulators Ra1 to Ra16 (16 in this embodiment) that adjust the pressure of the compressed gas in the pressure chambers C1 to C16. In Figure 2, some of the pressure chambers C1 to C16, gas transfer lines F1 to F16, and pressure regulators Ra1 to Ra16 are omitted from the illustration. The gas transfer lines F1 to F16 extend via a rotary joint 40 attached to the polishing head shaft 12. The pressure regulators Ra1 to Ra16 are attached to the gas transfer lines F1 to F16, respectively.

[0030] The gas transfer lines F1 to F16 are connected to a compressed gas supply source (not shown) which serves as a utility supply source in the factory where the polishing device 1 is installed. Compressed gas from the compressed gas supply source is supplied independently from the gas transfer lines F1 to F16 to the pressure chambers C1 to C16 via pressure regulators Ra1 to Ra16. The pressure regulators Ra1 to Ra16 are configured to regulate the pressure of the compressed gas in the pressure chambers C1 to C16.

[0031] Pressure regulators Ra1 to Ra16 are electrically connected to the operation control unit 50. The operation of pressure regulators Ra1 to Ra16 is controlled by the operation control unit 50. The operation control unit 50 sends the respective target pressure values ​​for pressure chambers C1 to C16 to the pressure regulators Ra1 to Ra16, and the pressure regulators Ra1 to Ra16 operate so that the pressure in pressure chambers C1 to C16 is maintained at the corresponding target pressure value.

[0032] The pressure regulators Ra1 to Ra16 can independently change the internal pressure of the pressure chambers C1 to C16. Therefore, the polishing head 11 can independently adjust the polishing pressure for multiple (16 in this embodiment) corresponding areas of the substrate W. For example, the polishing head 11 can press 16 areas of the substrate W surface corresponding to the pressure chambers C1 to C16 against the polishing surface 2a of the polishing pad 2 with different polishing pressures. Therefore, the polishing head system 10 can control the film thickness profile of the substrate W and achieve a target film thickness profile by adjusting the internal pressure of the pressure chambers C1 to C16. In this embodiment, since the pressure chambers C1 to C16 are arranged radially and circumferentially of the polishing head 11, the film thickness profile of the substrate W can be controlled in both the radial and circumferential directions.

[0033] The polishing head system 10 includes a plurality of vacuum lines Lb1 to Lb16 (16 in this embodiment) that communicate with a plurality of pressure chambers C1 to C16, and a plurality of vacuum valves Vb1 to Vb16 (16 in this embodiment) that form a negative pressure within the pressure chambers C1 to C16. The vacuum lines Lb1 to Lb16 are connected to gas transfer lines F1 to F16, respectively, upstream of the rotary joint 40. The vacuum valves Vb1 to Vb16 are attached to the vacuum lines Lb1 to Lb16, respectively. In Figure 2, some of the vacuum lines Lb1 to Lb16 and vacuum valves Vb1 to Vb16 are omitted from the illustration.

[0034] When vacuum valves Vb1 to Vb16 are opened while compressed gas is not being supplied, the gas in pressure chambers C1 to C16 is independently discharged to the outside through gas transfer lines F1 to F16 and vacuum lines Lb1 to Lb16, respectively, creating negative pressure within pressure chambers C1 to C16. When negative pressure is created within pressure chambers C1 to C16, the substrate W is held by vacuum suction against the pressing surface 34a of the elastic film 34. The pressure chamber that creates negative pressure when holding the substrate W may be a part of pressure chambers C1 to C16. Although not shown, pressure chambers C1 to C16 may each be connected to an atmospheric outlet line. Vacuum valves Vb1 to Vb16 are electrically connected to the operation control unit 50. The operation of vacuum valves Vb1 to Vb16 is controlled by the operation control unit 50.

[0035] Multiple retainer rollers 25 are arranged to surround the substrate W and the elastic film 34 of the polishing head 11. More specifically, the multiple retainer rollers 25 are arranged to surround the outer edge of the substrate W and the pressing surface 34a of the elastic film 34. Figure 4 is a side view of the polishing head system 10 shown in Figure 2. As shown in Figure 4, the polishing head system 10 includes multiple roller shafts 43, each connected to the multiple retainer rollers 25, and multiple retainer roller actuators 45, each connected to the multiple retainer rollers 25 via the multiple roller shafts 43.

[0036] Multiple retainer roller actuators 45 are arranged within the polishing head support arm 14. The multiple retainer roller actuators 45 are configured to operate independently of each other. That is, the multiple retainer roller actuators 45 are configured to rotate each of the multiple retainer rollers 25 independently, move the multiple retainer rollers 25 up and down relative to the polishing head 11, and move the multiple retainer rollers 25 radially with respect to the polishing head 11. The retainer rollers 25 are fixed to the lower end of the roller shaft 43. The roller shaft 43 extends parallel to the polishing head shaft 12.

[0037] Figure 5 is a schematic diagram showing one embodiment of the retainer roller actuator 45. Multiple retainer roller actuators 45 have basically the same configuration. As shown in Figure 5, the retainer roller actuator 45 includes a retainer roller rotation mechanism 55 that rotates the retainer roller 25, a retainer roller pressing mechanism 56 that presses the retainer roller 25 against the polishing pad 2, and a retainer roller moving mechanism 57 that moves the retainer roller 25 in the radial direction of the polishing head 11.

[0038] The retainer roller rotation mechanism 55 comprises a ball spline bearing 65, a motor 61, a pulley 62 mounted on the rotating shaft of the motor 61, and a belt 63 stretched over the pulley 62 and the ball spline bearing 65. The roller shaft 43 is supported by the ball spline bearing 65 so as to be able to move up and down. When the motor 61 is driven, the roller shaft 43 and the retainer roller 25 are rotated via the pulley 62, the belt 63, and the ball spline bearing 65. In this way, the retainer roller rotation mechanism 55 rotates the retainer roller 25, which is fixed to the roller shaft 43, around its axis.

[0039] The retainer roller pressing mechanism 56 is connected to the upper end of the roller shaft 43, which is supported by a ball spline bearing 65. The retainer roller pressing mechanism 56 is composed of, for example, an air cylinder. The retainer roller pressing mechanism 56 is configured to move the roller shaft 43 and the retainer roller 25 up and down. During polishing of the substrate W, the retainer roller pressing mechanism 56 applies a downward load to the retainer roller 25 and presses the lower surface of the retainer roller 25 against the polishing surface 2a of the polishing pad 2 with a predetermined pressing force.

[0040] The retainer roller rotation mechanism 55 and the retainer roller pressing mechanism 56 are fixed to the base member 69. Specifically, the motor 61 of the retainer roller rotation mechanism 55 is fixed to the bottom 69a of the base member 69, and the retainer roller pressing mechanism 56 is fixed to the upper wall 69b of the base member 69. The retainer roller moving mechanism 57 is connected to the base member 69. The retainer roller moving mechanism 57 is configured, for example, by a combination of a ball screw and a servo motor. The retainer roller moving mechanism 57 is configured to move the retainer roller rotation mechanism 55, the retainer roller pressing mechanism 56, the roller shaft 43, and the retainer roller 25 together in the radial direction of the polishing head 11 via the base member 69.

[0041] Of the multiple retainer roller actuators 45, the retainer roller actuator 45 connected to the downstream retainer roller, described later, is further equipped with a load measuring device (e.g., a load cell) 70 for measuring the radial load of the substrate W applied to the retainer roller 25. The load measuring device 70 is positioned between the retainer roller moving mechanism 57 and the base member 69. The load measuring device 70 is configured to measure the radial load of the substrate W applied from the substrate W to the retainer roller 25.

[0042] The retainer roller rotation mechanism 55, the retainer roller pressing mechanism 56, the retainer roller moving mechanism 57, and the load measuring device 70 are electrically connected to the operation control unit 50. The operation of the retainer roller rotation mechanism 55, the retainer roller pressing mechanism 56, and the retainer roller moving mechanism 57 is controlled by the operation control unit 50. The measured value of the radial load on the substrate W applied to the retainer roller 25 by the load measuring device 70 is sent to the operation control unit 50.

[0043] In the embodiment shown in Figure 5, the retainer roller actuator 45 includes a retainer roller rotation mechanism 55, a retainer roller pressing mechanism 56, and a retainer roller moving mechanism 57. However, the configuration of the retainer roller actuator 45 is not limited to the embodiment described with reference to Figure 5, as long as the retainer roller actuator 45 can rotate the retainer roller 25, press it against the polishing pad 2, and move it radially in the polishing head 11.

[0044] Figure 6 is a top view showing the arrangement of multiple retainer rollers 25. In this embodiment, five retainer rollers 25 are provided. Hereinafter, these five retainer rollers will be denoted by reference numerals 25A to 25E to distinguish them. As shown in Figure 6, the retainer rollers 25A to 25E include a plurality of downstream retainer rollers 25A, 25B, 25C, and 25D arranged downstream of the polishing head 11 in the direction of travel D1 of the polishing pad 2, and at least one (one in this embodiment) upstream retainer roller 25E arranged upstream of the polishing head 11 in the direction of travel D1 of the polishing pad 2 relative to the polishing head 11.

[0045] The rotation direction D3 of the retainer rollers 25A to 25E is opposite to the rotation direction D2 of the polishing head 11. During polishing of the substrate W, frictional force is applied to the substrate W between the polishing pad 2 and the substrate W. As the polishing pad 2 moves in the direction of travel D1, the substrate W is pressed against the retainer rollers 25A to 25D. During polishing of the substrate W, the downstream retainer rollers 25A to 25D are basically in contact with the substrate W, while the upstream retainer roller 25E is basically away from the substrate W.

[0046] The retainer rollers 25A to 25E are not in contact with the polishing head 11. The relative positions of the polishing head 11 and the retainer rollers 25A to 25E are fixed. In this embodiment, the relative positions of the downstream retainer rollers 25A to 25D with respect to the polishing head 11 are different from the relative positions of the upstream retainer roller 25E with respect to the polishing head 11. Specifically, the distance from each of the downstream retainer rollers 25A to 25D to the polishing head 11 is smaller than the distance from the upstream retainer roller 25E to the polishing head 11.

[0047] During polishing of the substrate W, the retainer rollers 25A to 25E are rotated by the retainer roller rotation mechanism 55 and pressed against the polishing surface 2a of the polishing pad 2 by the retainer roller pressing mechanism 56. The multiple retainer roller rotation mechanisms 55 are configured to rotate the retainer rollers 25A to 25E at the same speed and in the same direction. In one embodiment, some of the retainer rollers 25A to 25E (for example, retainer roller 25E) may be configured to rotate freely without being connected to the retainer roller rotation mechanism 55. The retainer rollers 25A to 25E have the function of preventing the substrate W from flying out of the polishing head 11 during polishing.

[0048] Figure 7 is a top view showing the oscillating motion of the polishing head 11 during polishing of the substrate W. As described above, the polishing head 11 is rotated around the pivot shaft 15 by the polishing head moving motor 18. In one embodiment, as shown in Figure 7, during polishing of the substrate W, the polishing head 11 is oscillated by the polishing head moving motor 18 between a first position P1, shown by a solid line, and a second position P2, shown by a dashed line. The first position P1 and the second position P2 are above the polishing pad 2. When the polishing head 11 moves between the first position P1 and the second position P2, the relative positions of the retainer rollers 25A to 25E with respect to the polishing head 11 in the circumferential direction change.

[0049] In this embodiment, the plurality of downstream retainer rollers 25A to 25D include first downstream retainer rollers 25A to 25C and a second downstream retainer roller 25D. When the polishing head 11 is in the first position P1, the first downstream retainer rollers 25A to 25C are positioned downstream of the polishing head 11 in the direction of travel D1 of the polishing pad 2. When the polishing head 11 is in the second position P2, the second downstream retainer roller 25D is positioned downstream of the polishing head 11 in the direction of travel D1 of the polishing pad 2. In this embodiment, when the polishing head 11 is in the second position P2, the first downstream retainer rollers 25B and 25C are positioned downstream of the polishing head 11 in the direction of travel D1 of the polishing pad 2. In this embodiment, the number of first downstream retainer rollers 25A to 25C is greater than the number of second downstream retainer rollers 25D.

[0050] As shown in Figure 6, the first downstream retainer rollers 25A-25C and the second downstream retainer roller 25D are positioned within an angle α1 in the circumferential direction of the polishing head 11. The angle α1 in the circumferential direction of the polishing head 11 includes the range in which the retainer rollers 25A-25D are maintained in the downstream position of the polishing head 11 in the direction of travel D1 of the polishing pad 2 while the polishing head 11 is moved between the first position P1 and the second position P2, as explained with reference to Figure 7. The angle α1 is 180 degrees or less. The upstream retainer roller 25E is positioned within an angle α2 in the circumferential direction of the polishing head 11. The angle α2 in the circumferential direction of the polishing head 11 is symmetrical to the angle α1 in the circumferential direction of the polishing head 11. The angle α2 is 180 degrees or less. In the example shown in Figure 6, angles α1 and α2 are 180 degrees.

[0051] The first downstream retainer rollers 25A to 25C are located further out than the second downstream retainer roller 25D in the radial direction of the polishing pad 2. The first downstream retainer roller 25A is located further out than the first downstream retainer roller 25B in the radial direction of the polishing pad 2, and the first downstream retainer roller 25B is located further out than the first downstream retainer roller 25C in the radial direction of the polishing pad 2. The angle α3 formed by the straight line B1 connecting the axis of the first downstream retainer roller 25A and the center CP of the polishing head 11, and the straight line B2 connecting the axis of the first downstream retainer roller 25C and the center CP of the polishing head 11, is 90 degrees or less. The second downstream retainer roller 25D is located closer to the first downstream retainer roller 25C than to the upstream retainer roller 25E in the circumferential direction of the polishing head 11.

[0052] In this embodiment, the first downstream retainer roller 25C and the upstream retainer roller 25E are arranged on a straight line B2 passing through the center CP of the polishing head 11. In other words, the first downstream retainer roller 25C and the upstream retainer roller 25E are arranged symmetrically with respect to the center CP of the polishing head 11.

[0053] In this embodiment, three first downstream retainer rollers 25A to 25C, one second downstream retainer roller 25D, and one upstream retainer roller 25E are provided, but the number of first downstream retainer rollers, second downstream retainer rollers, and upstream retainer rollers is not particularly limited in this embodiment. Furthermore, the arrangement of the first downstream retainer rollers, second downstream retainer rollers, and upstream retainer rollers is not particularly limited in this embodiment, as long as it can prevent the substrate W from flying off the polishing head 11 during polishing of the substrate W.

[0054] In one embodiment, the polishing head 11 does not need to be oscillated during polishing of the substrate W. In this case, the polishing head system 10 does not need to be equipped with a second downstream retainer roller 25D.

[0055] Polishing of the substrate W is performed as follows. The substrate W is held by the polishing head 11 with its surface to be polished facing downwards. The retainer rollers 25A to 25E are moved inward in the radial direction of the polishing head 11 by the retainer roller moving mechanism 57 and positioned in predetermined locations. While the polishing head 11, retainer rollers 25A to 25E, and polishing table 3 are rotated, polishing fluid (for example, a slurry containing abrasive particles) is supplied from the polishing fluid supply nozzle 8 located above the polishing table 3 onto the polishing surface 2a of the polishing pad 2. The polishing pad 2 rotates integrally with the polishing table 3 around its central axis. The polishing head 11 is lowered to a predetermined height by the polishing head lifting mechanism 22, and at the same time, the retainer rollers 25A to 25E are lowered to a predetermined height by the retainer roller pressing mechanism 56.

[0056] Subsequently, while the polishing head 11 is maintained at the predetermined height, gas is supplied into the pressure chambers C1 to C16, causing the polishing head 11 to press the substrate W against the polishing surface 2a of the polishing pad 2. The substrate W rotates in conjunction with the rotation of the polishing head 11 and the retainer rollers 25A to 25E. As a result, the substrate W is brought into sliding contact with the polishing surface 2a in the presence of the polishing fluid. The surface of the substrate W is polished by a combination of the chemical action of the polishing fluid and the mechanical action of the abrasive grains contained in the polishing fluid and / or the polishing pad 2. During the polishing of the substrate W, the retainer rollers 25A to 25E are pressed against the polishing surface 2a of the polishing pad 2 by the retainer roller pressing mechanism 56.

[0057] When polishing the substrate W is complete, the supply of gas to the pressure chambers C1-C16 is stopped, and the polishing head 11 again holds the substrate W by adsorption. Subsequently, the polishing head 11 is raised by the polishing head lifting mechanism 22, and at the same time, the retainer rollers 25A-25E are raised by the retainer roller pressing mechanism 56. The rotation of the polishing head 11, the retainer rollers 25A-25E, and the polishing table 3 is stopped.

[0058] According to this embodiment, since the polishing head system 10 is equipped with a plurality of retainer rollers 25A to 25E, there is no closed gap between the elastic film and the retainer ring, unlike conventional polishing heads equipped with retainer rings. Therefore, the polishing fluid does not remain inside the polishing head, and the generation of particles caused by the polishing fluid can be prevented.

[0059] As shown in Figure 1, the polishing apparatus 1 is equipped with a notch detector 80 that detects notches formed in the substrate W. The notches are notches that identify the crystal orientation of the silicon in the substrate W and are formed on the periphery of the substrate W. Conventional retainer rings are arranged to surround the entire circumference of the substrate W, so it was not possible to detect the notches from outside the polishing head 11 during polishing of the substrate W. In this embodiment, the periphery of the substrate W is exposed between the retainer rollers 25A to 25E, so it is possible to detect the notches from outside the polishing head 11 during polishing of the substrate W.

[0060] In this embodiment, the notch detector 80 is attached to the support shaft 15 and positioned facing the peripheral edge of the substrate W held by the polishing head 11. The notch detector 80 may be fixed to a support member other than the support shaft 15. In one example, the notch detector 80 is an imaging device that generates an image of the peripheral edge of the substrate W and is configured to generate an image of the peripheral edge of the substrate W and detect notches on the image. In another example, the notch detector 80 is an optical notch detector that irradiates the peripheral edge of the substrate W with laser light and detects the reflected laser light with a light receiving unit. When laser light is irradiated onto a notch, the intensity of the laser light reflected from the substrate W changes. Therefore, the optical notch detector is configured to detect notches based on the change in the intensity of the laser light reflected from the peripheral edge of the substrate W. However, the arrangement and specific configuration of the notch detector 80 are not particularly limited as long as it can detect notches.

[0061] The notch detector 80 is electrically connected to the operation control unit 50, and the notch detection signal from the notch detector 80 is sent to the operation control unit 50. The operation control unit 50 is configured to determine the relative circumferential position of the notch with respect to the reference position of the polishing head 11 based on the notch detection signal sent from the notch detector 80 and the detected value of the rotation angle of the polishing head rotation mechanism 20 (i.e., the detected value of the rotation angle of the polishing head 11) sent from the rotary encoder 21. The reference position of the polishing head 11 is a predetermined position in the circumferential direction of the polishing head 11. In this embodiment, the reference position of the polishing head 11 is the circumferential position of the polishing head 11 that corresponds to the position of the notch when the polishing head 11 holds the substrate W before polishing the substrate W.

[0062] The substrate W is polished while being rotated by the polishing head 11 and retainer rollers 25A to 25E. In particular, during polishing of the substrate W, the peripheral edge of the substrate W is strongly pressed against the first downstream retainer rollers 25A to 25C (see Figure 6), so the rotation of the first downstream retainer rollers 25A to 25C can apply torque to the substrate W. The substrate W is rotated in conjunction with the rotation of the polishing head 11 and retainer rollers 25A to 25E.

[0063] During polishing of the substrate W, the substrate W may not follow the rotation of the polishing head 11, causing a misalignment between the reference position of the polishing head 11 and the position of the notches on the substrate W in the circumferential direction of the polishing head 11. If the reference position of the polishing head 11 and the position of the notches on the substrate W are misaligned during polishing, the positional relationship between the pressure chambers C1 to C16 and the 16 corresponding different regions on the surface of the substrate W changes. In particular, as in this embodiment, when the internal pressure of the circumferentially arranged pressure chambers C1 to C16 is adjusted to control the circumferential film thickness profile of the substrate W, it becomes impossible to control the film thickness profile with high accuracy.

[0064] Therefore, the operation control unit 50 of this embodiment is configured to rotate the retainer rollers 25A to 25E by issuing a command to the retainer roller rotation mechanism 55 so that the position of the notch in the circumferential direction of the polishing head 11 coincides with the reference position of the polishing head 11, based on the relative circumferential position of the notch with respect to the reference position of the polishing head 11. In one embodiment, the operation control unit 50 may continuously acquire a notch detection signal from the notch detector 80 and change the rotation speed of the retainer rollers 25A to 25E by issuing a command to the retainer roller rotation mechanism 55 so that the position of the notch coincides with the reference position of the polishing head 11.

[0065] In other embodiments, the operation control unit 50 monitors the relative circumferential position of the notch with respect to the reference position of the polishing head 11, and commands the retainer roller rotation mechanism 55 to rotate the retainer rollers 25A to 25E so that the position of the notch in the circumferential direction of the polishing head 11 coincides with the reference position of the polishing head 11. The correlation between the relative circumferential position of the notch with respect to the reference position of the polishing head 11 and the number of rotations of the retainer rollers 25A to 25E is acquired in advance based on experimental results, etc., and stored in the operation control unit 50. The number of rotations of the retainer rollers 25A to 25E is determined based on this correlation.

[0066] In one embodiment, the operation control unit 50 may be configured to adjust the pressure in each of the pressure chambers C1 to C16 by issuing commands to pressure regulators Ra1 to Ra16 based on the circumferential position of the notch relative to the reference position of the polishing head 11. Specifically, the operation control unit 50 determines the target pressure value for each of the pressure chambers C1 to C16 based on the circumferential position of the notch relative to the reference position of the polishing head 11 and the current target pressure value for each of the pressure chambers C1 to C16, and adjusts the pressure in each of the pressure chambers C1 to C16 by sending the determined target pressure value to the pressure regulators Ra1 to Ra16.

[0067] For example, if the relative circumferential position of the notch is shifted 90 degrees clockwise with respect to the reference position of the polishing head 11, the same pressure value as the current target pressure value of each of the pressure chambers C1 to C16 will be determined as the target pressure value of the pressure chamber located 90 degrees clockwise circumferentially from each of the pressure chambers C1 to C16 relative to the polishing head 11. That is, the same pressure value as the current target pressure value of pressure chamber C2 will be determined as the target pressure value of pressure chamber C1, which is located 90 degrees clockwise circumferentially from pressure chamber C2 relative to the polishing head 11. The target pressure values ​​for pressure chambers C2 to C16 will be determined similarly.

[0068] Figure 8 is a schematic cross-sectional view showing the positional relationship between the substrate W and the pad rebound due to the pressing force of the retainer rollers. In Figure 8, as an example, the pad rebound due to the first downstream retainer roller 25C and the upstream retainer roller 25E is explained. The first downstream retainer roller 25C and the upstream retainer roller 25E are arranged on both sides of the substrate W. When the retainer roller pressing mechanism 56 applies a pressing force (local load) L1 to the first downstream retainer roller 25C against the polishing surface 2a of the polishing pad 2, a pad rebound R1 of the polishing pad 2 occurs. Similarly, when the retainer roller pressing mechanism 56 applies a pressing force (local load) L2 to the upstream retainer roller 25E against the polishing surface 2a of the polishing pad 2, a pad rebound R2 of the polishing pad 2 occurs.

[0069] By applying pressing forces L1 and L2 to the polishing pad 2 and generating pad rebounds R1 and R2, the polishing rate of the peripheral edge of the substrate W can be locally varied. In Figure 8, for illustrative purposes, only the raised portion of the polishing surface 2a is in contact with the substrate W, but in actual polishing, the entire lower surface (the surface to be polished) of the substrate W is in contact with the polishing surface 2a.

[0070] In conventional polishing heads equipped with retainer rings, applying localized loads simultaneously to two parts of the retainer ring located on both sides of the substrate W causes the entire rigid retainer ring to be pressed against the polishing pad 2. Therefore, it was difficult to apply localized loads to different parts of the polishing pad 2. According to this embodiment, the multiple retainer roller pressing mechanisms 56 can independently press the retainer rollers 25A to 25E against the polishing pad 2, thus enabling the application of localized loads to different parts of the polishing pad 2.

[0071] As described above, during polishing of the substrate W, the substrate W is biased downstream in the direction of travel D1 of the polishing pad 2, so the relative position of pad rebound R1 with respect to the substrate W is different from the relative position of pad rebound R2 with respect to the substrate W. In other words, the distance of pad rebound R1 from the center of the substrate W is different from the distance of pad rebound R2 from the center of the substrate W. In this embodiment, during polishing of the substrate W, the downstream retainer roller 25C is in contact with the peripheral edge of the substrate, while the upstream retainer roller 25E is away from the peripheral edge of the substrate W. Before or during polishing of the substrate W, the operation control unit 50 can control the film thickness profile of the substrate W by giving a command to the retainer roller moving mechanism 57 to adjust the position of the upstream retainer roller 25E in the radial direction of the polishing head 11, thereby adjusting the position at which pad rebound R2 is generated.

[0072] As shown in Figure 1, the polishing apparatus 1 is equipped with a film thickness sensor 85 for measuring the film thickness of the substrate W. The film thickness sensor 85 is configured to generate a film thickness index value that directly or indirectly indicates the film thickness of the substrate W. This film thickness index value changes according to the film thickness of the substrate W. The film thickness index value may be a value that represents the film thickness of the substrate W itself, or it may be a physical quantity or signal value before it is converted to film thickness.

[0073] Examples of the film thickness sensor 85 include eddy current sensors and optical film thickness sensors. The film thickness sensor 85 is installed inside the polishing table 3 and rotates together with the polishing table 3. More specifically, the film thickness sensor 85 is configured to measure the film thickness at multiple measurement points on the substrate W while traversing the substrate W on the polishing surface 2a each time the polishing table 3 rotates once. The film thickness sensor 85 is electrically connected to the operation control unit 50. The film thickness at the multiple measurement points is output from the film thickness sensor 85 as a film thickness index value, and the film thickness index value is sent to the operation control unit 50. The operation control unit 50 is configured to control the operation of the polishing head system 10 based on the film thickness index value.

[0074] The motion control unit 50 creates a film thickness profile of the substrate W from the film thickness index values ​​output from the film thickness sensor 85. The film thickness profile of the substrate W is a distribution of film thickness index values. The film thickness measurement points are aligned along the radial direction of the substrate W. Therefore, the film thickness index values ​​output from the film thickness sensor 85 are distributed along the radial direction of the substrate W. The film thickness profile is a film thickness profile along the radial direction of the substrate W.

[0075] The motion control unit 50 is configured to adjust the position of the upstream retainer roller 25E in the radial direction of the polishing head 11 by issuing a command to the retainer roller moving mechanism 57 connected to the upstream retainer roller 25E based on the film thickness profile, and to adjust the pressing force of the upstream retainer roller 25E against the polishing pad 2 by issuing a command to the retainer roller pressing mechanism 56. This makes it possible to adjust the position and magnitude of the pad rebound of the polishing pad 2 generated by the upstream retainer roller 25E.

[0076] In one embodiment, the operation control unit 50 may be configured to adjust the pressing force of the downstream retainer rollers 25A to 25D against the polishing pad 2 by issuing commands to the retainer roller pressing mechanism 56 connected to the downstream retainer rollers 25A to 25D based on the film thickness profile. This makes it possible to adjust the amount of pad rebound of the polishing pad 2 generated by the downstream retainer rollers 25A to 25D.

[0077] Figure 9(a) is a top view of a conventional polishing head equipped with a retainer ring 115, and Figure 9(b) is a cross-sectional view of the portion of the retainer ring 115 located downstream of the substrate W in the direction of travel D1 of the polishing pad 2, and of the substrate W. As shown in Figure 9(a), during polishing of the substrate W, the substrate W held by a polishing head (not shown) is biased downstream of the polishing head in the direction of travel D1 of the polishing pad 2. Therefore, in a conventional polishing head, the substrate W is in contact with the downstream portion of the retainer ring 115 (the portion shown by the dashed line in Figure 9(a)) in the direction of travel D1 of the polishing pad 2 during polishing of the substrate W.

[0078] If the radial load on the substrate W applied to the downstream portion of the retainer ring 115 is large, the peripheral edge of the substrate W will deform and sink into the polishing pad 2, as shown in Figure 9(b). Such deformation of the substrate W affects the polishing rate of the peripheral edge of the substrate W, making it difficult to accurately control the film thickness profile of the substrate W.

[0079] Figure 10(a) is a top view of the polishing head system 10 according to this embodiment, and Figure 10(b) is a cross-sectional view of the retainer roller 25B and the substrate W, which are arranged downstream of the substrate W in the direction of travel D1 of the polishing pad 2. As shown in Figure 10(a), in the polishing head system 10 of this embodiment, a plurality of downstream retainer rollers 25A to 25D are arranged downstream of the substrate W in the direction of travel D1 of the polishing pad 2. Therefore, the radial load on the substrate W is distributed to the downstream retainer rollers 25A to 25D. Consequently, the radial load on the substrate W applied to each of the downstream retainer rollers 25A to 25D is smaller than the radial load applied to the conventional retainer ring 115 shown in Figure 9(a). As a result, deformation of the peripheral edge of the substrate W can be prevented, as shown in Figure 10(b).

[0080] As shown in Figure 5, the retainer roller actuator 45 is equipped with a load measuring device 70 that measures the radial load of the substrate W applied to the retainer roller 25 during polishing of the substrate W. The radial load of the substrate W is the load on the substrate W in the radial direction of the polishing head 11 or the substrate W. In this embodiment, the load measuring device 70 is provided on the retainer roller actuator 45 connected to the downstream retainer rollers 25A to 25D, but not on the retainer roller actuator 45 connected to the upstream retainer roller 25E. The measured value of the radial load of the substrate W applied to the downstream retainer rollers 25A to 25D by the load measuring device 70 is sent to the operation control unit 50. In one embodiment, the load measuring device 70 may also be provided on the retainer roller actuator 45 connected to the upstream retainer roller 25E, or it may be provided only on the retainer roller actuator 45 connected to the first downstream retainer rollers 25A to 25C.

[0081] The motion control unit 50 is configured to adjust the positions of the downstream retainer rollers 25A to 25D by the retainer roller moving mechanism 57 so that the radial load of the substrate W applied to the downstream retainer rollers 25A to 25D is evenly distributed, based on the measured value of the radial load of the substrate W applied to the downstream retainer rollers 25A to 25D during the polishing of the substrate W. This evenly distributes the radial load of the substrate W applied to the downstream retainer rollers 25A to 25D, thereby reducing the radial load of the substrate W applied to each of the downstream retainer rollers 25A to 25D.

[0082] Figure 11 is a top view illustrating the polishing position P3 and the transfer position P4 of the substrate W. The polishing head 11 is movable between the polishing position P3 of the substrate W, shown by a solid line, and the transfer position P4 of the substrate W, shown by a dashed line. More specifically, the polishing head 11 and retainer rollers 25A to 25E can move between the polishing position P3 and the transfer position P4 by the rotation of the polishing head support arm 14 by the polishing head moving motor 18 (see Figure 1). The polishing position P3 is above the polishing surface 2a of the polishing pad 2, and the transfer position P4 is located outside the polishing surface 2a. The substrate W before polishing is transported to the transfer position P4 by a transport device (not shown), and the substrate W after polishing is transported out from the transfer position P4 by the transport device.

[0083] The polishing apparatus 1 further comprises a cleaning apparatus 90 for cleaning the polishing head 11 and a plurality of retainer rollers 25A to 25E. The cleaning apparatus 90 is positioned radially outward from the polishing head 11 and the plurality of retainer rollers 25A to 25E at the transfer position P4. The cleaning apparatus 90 is configured to clean the polishing head 11 and the plurality of retainer rollers 25A to 25E at the transfer position P4. The cleaning apparatus 90 cleans the polishing head 11 and the plurality of retainer rollers 25A to 25E after the substrate W has been polished and the substrate W has been discharged from the polishing apparatus 1 by the transport apparatus. The cleaning apparatus 90 cleans the polishing head 11 and the plurality of retainer rollers 25A to 25E each time the substrate W is polished.

[0084] Figure 12 is a top view showing one embodiment of the cleaning device 90. The cleaning device 90 includes roller cleaning members 92A to 92E for cleaning a plurality of retainer rollers 25A to 25E, a polishing head cleaning member 93 for cleaning the polishing head 11, and a plurality of liquid supply nozzles 95 (six in this embodiment) for supplying liquid (for example, a rinsing liquid such as pure water) to the roller cleaning members 92A to 92E and the polishing head cleaning member 93.

[0085] The roller cleaning members 92A to 92E are configured to contact the sides of the retainer rollers 25A to 25E, respectively. The polishing head cleaning member 93 is configured to contact the side of the polishing head 11. The contact surfaces of the roller cleaning members 92A to 92E with the retainer rollers 25A to 25E have an arc shape that follows the sides of the retainer rollers 25A to 25E. The contact surface of the polishing head cleaning member 93 with the polishing head 11 has an arc shape that follows the side of the polishing head 11. However, the shapes of the roller cleaning members 92A to 92E and the polishing head cleaning member 93 are not limited to this embodiment and may have other shapes. For example, the roller cleaning members 92A to 92E and the polishing head cleaning member 93 may have a cylindrical shape. Examples of materials for the roller cleaning members 92A to 92E and the polishing head cleaning member 93 include PU (polyurethane) and PVAc (polyvinyl acetal). In one embodiment, the roller cleaning members 92A to 92E and the polishing head cleaning member 93 may be buff cleaning members.

[0086] The six liquid supply nozzles 95 are configured to supply liquid to the contact points between the retainer roller 25A and the roller cleaning member 92A, the contact points between the retainer roller 25B and the roller cleaning member 92B, the contact points between the retainer roller 25C and the roller cleaning member 92C, the contact points between the retainer roller 25D and the roller cleaning member 92D, the contact points between the retainer roller 25E and the roller cleaning member 92E, and the contact points between the polishing head 11 and the polishing head cleaning member 93, respectively. However, the number and arrangement of the liquid supply nozzles 95 are not particularly limited to this embodiment.

[0087] The cleaning device 90 further includes a plurality of cleaning member moving mechanisms 98 that move the roller cleaning members 92A to 92E and the polishing head cleaning member 93 in the radial direction of the polishing head 11, respectively. The plurality of cleaning member moving mechanisms 98 are connected to the roller cleaning members 92A to 92E and the polishing head cleaning member 93, respectively. The plurality of cleaning member moving mechanisms 98 have basically the same configuration. Examples of cleaning member moving mechanisms 98 include a combination of a ball screw and a servo motor, and an air cylinder.

[0088] By rotating the retainer rollers 25A to 25E and supplying liquid through the liquid supply nozzle 95, the roller cleaning members 92A to 92E are brought into contact with the retainer rollers 25A to 25E respectively by the cleaning member moving mechanism 98, thereby cleaning the retainer rollers 25A to 25E. Similarly, by rotating the polishing head 11 and supplying liquid through the liquid supply nozzle 95, the polishing head 11 is brought into contact with the polishing head 11 by the polishing head cleaning member 93.

[0089] In one embodiment, each of the roller cleaning members 92A to 92E and the polishing head cleaning member 93 may be equipped with an inner rinse pipe for supplying liquid from the inside. In this case, the cleaning device 90 does not need to be equipped with a liquid supply nozzle 95. When liquid is supplied to the roller cleaning members 92A to 92E and the polishing head cleaning member 93 from the inner rinse pipe, the liquid is discharged to the outside of the roller cleaning members 92A to 92E and the polishing head cleaning member 93. By rotating the retainer rollers 25A to 25E and supplying liquid from the inner rinse pipe, the roller cleaning members 92A to 92E can be brought into contact with the retainer rollers 25A to 25E by the cleaning member moving mechanism 98, respectively, thereby cleaning the retainer rollers 25A to 25E. Similarly, by rotating the polishing head 11 and supplying liquid from the inner rinse pipe, the polishing head cleaning member 93 can be brought into contact with the polishing head 11, thereby cleaning the polishing head 11.

[0090] 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]

[0091] 1 Polishing equipment 2 polishing pads 2a Polished surface 3 Polishing Table 5 Table shaft 6 Table motors 8. Polishing fluid supply nozzle 10 Polishing Head Systems 11 Polishing heads 12 Polished Head Shafts 14 Polishing head support arm 15 Spindle 18. Polishing head moving motor 20. Polishing head rotation mechanism 21 Rotary Encoder 22 Polishing head lifting mechanism 25 Retainer Rollers 25A, 25B, 25C Downstream retainer rollers (first downstream retainer rollers) 25D Downstream retainer roller (second downstream retainer roller) 25E Upstream retainer roller 31 Careers 34 Elastic membrane 34a Pressing surface 34b,34c,34d,34e 1st bulkhead 34f,34g 2nd bulkhead 40 Rotary Joint 43 Roller shaft 45 Retainer Roller Actuator 50 Operation Control Unit 50a storage device 50b Arithmetic unit 55 Retainer roller rotation mechanism 56 Retainer roller pressing mechanism 57 Retainer roller moving mechanism 61 Motor 62 Pulley 63 belts 65 Ball spline bearings 69 Base member 70 Load measuring device 80-notch detector 85 Film Thickness Sensor 90 Washing device 92A, 92B, 92C, 92D, 92E Roller cleaning components 93 Polishing head cleaning component 95 Liquid supply nozzle 98 Cleaning Member Transfer Mechanism C1-C16 Pressure Chambers F1~F16 Gas Transfer Line Ra1~Ra16 Pressure Regulator Lb1~Lb16 Vacuum Line Vb1~Vb16 Vacuum valves

Claims

1. A polishing head for pressing the circuit board against the polishing pad, Multiple retainer rollers are arranged to surround the polishing head, A polishing head system comprising a retainer roller pressing mechanism that presses the plurality of retainer rollers against the polishing pad.

2. The polishing head system according to claim 1, further comprising a retainer roller rotation mechanism for rotating at least one of the plurality of retainer rollers.

3. The polishing head system according to claim 1, wherein the retainer roller pressing mechanism is a plurality of retainer roller pressing mechanisms that press the plurality of retainer rollers against the polishing pad, respectively.

4. The polishing head system according to claim 1, further comprising a retainer roller moving mechanism for moving at least one of the plurality of retainer rollers in the radial direction of the polishing head.

5. The polishing head includes an elastic membrane that forms a pressure chamber for pressing the substrate against the polishing pad, The polishing head system according to claim 1, further comprising a pressure regulator for adjusting the pressure in the pressure chamber.

6. A polishing head system according to any one of claims 1 to 5, A polishing table that supports the polishing pad, A polishing apparatus equipped with a table motor for rotating the polishing table.

7. The polishing apparatus according to claim 6, wherein the plurality of retainer rollers include a plurality of downstream retainer rollers arranged downstream of the polishing head in the direction of travel of the polishing pad, and at least one upstream retainer roller arranged upstream of the polishing head in the direction of travel.

8. The system further includes a polishing head moving motor that oscillates the polishing head between a first position and a second position. The plurality of downstream retainer rollers include a first downstream retainer roller and a second downstream retainer roller, The first downstream retainer roller is positioned downstream of the polishing head in the direction of travel of the polishing pad when the polishing head is in the first position. The polishing apparatus according to claim 7, wherein the second downstream retainer roller is positioned downstream of the polishing head in the direction of travel when the polishing head is in the second position.

9. The polishing apparatus according to claim 6, further comprising a cleaning device for cleaning the polishing head and the plurality of retainer rollers.

10. The polishing head system according to claim 2, A polishing table that supports the polishing pad, A table motor for rotating the polishing table, A notch detector for detecting a notch formed on the peripheral edge of the substrate, The system includes an operation control unit that controls the operation of the retainer roller rotation mechanism, The aforementioned operation control unit, Based on the detection signal of the notch, the relative circumferential position of the notch with respect to the reference position of the polishing head is determined. A polishing device configured to rotate the plurality of retainer rollers by giving a command to the retainer roller rotation mechanism so that the position of the notch in the circumferential direction of the polishing head coincides with the reference position, based on the relative circumferential position of the notch with respect to the reference position of the polishing head.

11. The polishing head system according to claim 4, A polishing table that supports the polishing pad, A table motor for rotating the polishing table, An operation control unit that controls the operation of the retainer roller pressing mechanism and the retainer roller moving mechanism, The substrate is equipped with a film thickness sensor for obtaining the film thickness profile, The plurality of retainer rollers include an upstream retainer roller positioned upstream of the polishing head in the direction of travel of the polishing pad. The retainer roller moving mechanism is configured to move the upstream retainer roller in the radial direction, The polishing apparatus is configured such that the operation control unit gives a command to the retainer roller moving mechanism to adjust the position of the upstream retainer roller in the radial direction based on the film thickness profile, and gives a command to the retainer roller pressing mechanism to adjust the pressing force of the upstream retainer roller against the polishing pad.

12. The polishing head system according to claim 4, A polishing table that supports the polishing pad, A table motor for rotating the polishing table, The system includes an operation control unit that controls the operation of the retainer roller moving mechanism, The plurality of retainer rollers include a plurality of downstream retainer rollers positioned downstream of the polishing head in the direction of travel of the polishing pad, The retainer roller moving mechanism is a plurality of retainer roller moving mechanisms that move the plurality of downstream retainer rollers in the radial direction, The polishing head system further includes a load measuring device for measuring the radial load on the substrate applied to the plurality of downstream retainer rollers, Polishing apparatus, wherein the operation control unit is configured to adjust the positions of the plurality of downstream retainer rollers in the radial direction by issuing commands to the plurality of retainer roller moving mechanisms so that the radial load of the substrate applied to the plurality of downstream retainer rollers is uniform, based on a measurement of the radial load of the substrate.

13. The polishing head system according to claim 5, A polishing table that supports the polishing pad, A table motor for rotating the polishing table, A notch detector for detecting a notch formed on the peripheral edge of the substrate, The system includes an operation control unit that controls the operation of the pressure regulator, The pressure chamber is a plurality of pressure chambers arranged in the circumferential direction. The pressure regulator is a plurality of pressure regulators that adjust the pressure in the plurality of pressure chambers, The aforementioned operation control unit, Based on the detection signal of the notch, the relative circumferential position of the notch with respect to the reference position of the polishing head is determined. A polishing device configured to adjust the pressure in each of the multiple pressure chambers by issuing commands to the multiple pressure regulators based on the relative position of the notch with respect to the reference position of the polishing head.

14. While rotating the polishing table that supports the polishing pad, the polishing head presses the substrate against the polishing pad to polish the substrate. A polishing method comprising pressing a plurality of retainer rollers, arranged to surround the polishing head, against the polishing pad using a retainer roller pressing mechanism while polishing the substrate.

15. The polishing method according to claim 14, further comprising pressing the plurality of retainer rollers against the polishing pad by the retainer roller pressing mechanism, while rotating at least one of the plurality of retainer rollers by the retainer roller rotating mechanism.

16. The polishing method according to claim 14, wherein pressing the plurality of retainer rollers against the polishing pad by the retainer roller pressing mechanism means pressing each of the plurality of retainer rollers against the polishing pad by the plurality of retainer roller pressing mechanisms.

17. The polishing method according to claim 14, further comprising moving at least one of the plurality of retainer rollers in the radial direction of the polishing head by a retainer roller moving mechanism.

18. The polishing head includes an elastic membrane that forms a pressure chamber for pressing the substrate against the polishing pad, The polishing method according to claim 14, wherein pressing the substrate against the polishing pad with the polishing head is performed by adjusting the pressure in the pressure chamber to press the substrate against the polishing pad with the elastic membrane.

19. The polishing method according to claim 14, wherein the plurality of retainer rollers include a plurality of downstream retainer rollers arranged downstream of the polishing head in the direction of travel of the polishing pad, and at least one upstream retainer roller arranged upstream of the polishing head in the direction of travel.

20. The polishing of the substrate further includes oscillating the polishing head between a first position and a second position, The plurality of downstream retainer rollers include a first downstream retainer roller and a second downstream retainer roller, The first downstream retainer roller is positioned downstream of the polishing head in the direction of travel of the polishing pad when the polishing head is in the first position. The polishing method according to claim 19, wherein the second downstream retainer roller is positioned downstream of the polishing head in the direction of travel when the polishing head is in the second position.

21. The polishing method according to claim 14, further comprising cleaning the polishing head and the plurality of retainer rollers with a cleaning device after the substrate has been polished and the substrate has been removed from the polishing device.

22. During the polishing of the substrate, a notch detector is used to detect a notch formed on the peripheral edge of the substrate. Based on the detection signal of the notch, the relative circumferential position of the notch with respect to the reference position of the polishing head is determined. The polishing method according to claim 14, further comprising rotating the plurality of retainer rollers so that the position of the notch coincides with the reference position in the circumferential direction of the polishing head, based on the relative circumferential position of the notch with respect to the reference position of the polishing head.

23. The plurality of retainer rollers include an upstream retainer roller positioned upstream of the polishing head in the direction of travel of the polishing pad. The aforementioned polishing method is During the polishing of the substrate, the film thickness profile of the substrate is acquired by a film thickness sensor. The polishing method according to claim 14, further comprising adjusting the position of the upstream retainer roller in the radial direction of the polishing head and the pressing force of the upstream retainer roller against the polishing pad based on the film thickness profile.

24. The plurality of retainer rollers include a plurality of downstream retainer rollers positioned downstream of the polishing head in the direction of travel of the polishing pad, The aforementioned polishing method is During the polishing of the substrate, the radial load of the substrate applied to the plurality of downstream retainer rollers is measured using a load measuring device. The polishing method according to claim 14, further comprising adjusting the positions of the plurality of downstream retainer rollers in the radial direction so that the radial load of the substrate applied to the plurality of downstream retainer rollers is uniform, based on a measurement of the radial load of the substrate.

25. The pressure chamber is a plurality of pressure chambers arranged in the circumferential direction. During the polishing of the substrate, a notch detector is used to detect a notch formed on the peripheral edge of the substrate. The method further includes determining the relative circumferential position of the notch with respect to a reference position of the polishing head based on the detection signal of the notch. The polishing method according to claim 18, wherein pressing the substrate against the polishing pad with the polishing head involves adjusting the pressure in each of the plurality of pressure chambers based on the relative circumferential position of the notch with respect to the reference position of the polishing head, thereby pressing the substrate against the polishing pad with the elastic membrane.

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