Non-contact pad cleaning device

Abstract

The present invention provides a non-contact pad cleaning device capable of removing foreign matter from fine holes formed in a polishing surface of a polishing pad. A non-contact pad cleaning device is provided with: a rotary table (5) for rotating a polishing pad (2); a plurality of two-fluid nozzles (8) provided above the polishing pad (2); and a liquid supply line (61) and a gas supply line (65) connected to the plurality of two-fluid nozzles (8). The plurality of two-fluid nozzles (8) are arranged side by side in the radial direction of the polishing pad (2). When viewed from a direction perpendicular to the polishing surface (2a) of the polishing pad (2), the discharge ports (8a) of the plurality of two-fluid nozzles (8) are inclined with respect to a reference line (RL) extending in the radial direction of the polishing pad (2).

Description

Technical Field

[0001] The present invention relates to a non-contact pad cleaning device that uses a fluid to clean the polishing surface of a polishing pad, which is used to polish workpieces such as wafers, substrates, and wiring panels. Background Art

[0002] A polishing device is a device for polishing workpieces such as wafers, substrates, and wiring panels used in the manufacture of semiconductor devices. The workpiece slides in contact with the polishing surface of the polishing pad in the presence of a slurry, thereby polishing the surface of the workpiece. In order to maintain the polishing performance of the polishing pad, a dresser is used to dress the polishing surface of the polishing pad. Specifically, the dresser regenerates the polishing surface of the polishing pad by sliding the dressing surface fixed with abrasive grains such as diamond grains in contact with the polishing surface of the polishing pad, thereby slightly cutting the polishing surface of the polishing pad.

[0003] Microscopic holes are formed in the polishing surface of the polishing pad. Foreign substances such as polishing debris of the workpiece, abrasive grains contained in the slurry, and cutting debris of the polishing pad accumulate in these holes. Therefore, in order to remove foreign substances from the holes, while rotating the polishing pad, a jet of pure water from an atomizer is brought into contact with the polishing surface, thereby washing the foreign substances out of the polishing pad with pure water.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-200552

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2013-99828

[0008] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2016-97465

[0009] Problems to be Solved by the Invention

[0010] However, since the polishing surface of the polishing pad is wide, foreign substances temporarily removed from the holes by the jet of pure water from the atomizer may adhere to the polishing surface again. In addition, when the polishing pad is dressed using a dresser, since the polishing surface of the polishing pad is slightly cut, foreign substances accumulated in the holes of the polishing pad cannot be completely removed. As a result, the workpiece is polished in a state where foreign substances remain on the polishing pad. The foreign substances remaining on the polishing pad cause scratches on the workpiece. In addition, foreign substances attached to the workpiece contaminate the cleaning tools used in the cleaning process performed after the polishing process. In addition, foreign substances attached to the workpiece may cause defects in the semiconductor device. Summary of the Invention

[0011] Therefore, the present invention provides a non-contact pad cleaning device capable of removing foreign substances from microscopic holes formed in the polishing surface of a polishing pad.

[0012] Technical means for solving technical problems

[0013] In one aspect, a non-contact polishing pad cleaning device is provided for cleaning a polishing surface of a polishing pad for polishing a workpiece in a non-contact manner, comprising: a rotating table for rotating the polishing pad; a plurality of two-fluid nozzles arranged above the polishing pad; and a liquid supply line and a gas supply line connected to the plurality of two-fluid nozzles, the plurality of two-fluid nozzles being arranged in a radial direction of the polishing pad, and outlets of the plurality of two-fluid nozzles being inclined with respect to a reference line extending in the radial direction of the polishing pad when viewed from a direction perpendicular to the polishing surface of the polishing pad.

[0014] In one aspect, the outlets of the plurality of two-fluid nozzles are inclined in a direction the same as the rotation direction of the polishing pad when viewed from a direction perpendicular to the polishing surface of the polishing pad.

[0015] In one aspect, the outlets of the plurality of two-fluid nozzles are located on the reference line when viewed from a direction perpendicular to the polishing surface of the polishing pad.

[0016] In one aspect, an inclination angle of the outlets of the plurality of two-fluid nozzles with respect to the reference line increases as a distance of each two-fluid nozzle from the center of the polishing pad increases.

[0017] In one aspect, a distance of the outlets of the plurality of two-fluid nozzles from the reference line increases as a distance of each two-fluid nozzle from the center of the polishing pad increases, and the distance of the outlet of each two-fluid nozzle from the reference line is a distance from the reference line toward the downstream side in the rotation direction of the polishing pad.

[0018] In one aspect, the non-contact pad cleaning device further comprises a fine bubble generator connected to the liquid supply line.

[0019] In one aspect, the non-contact pad cleaning device further comprises a liquid heating device connected to the liquid supply line and heating liquid flowing in the liquid supply line.

[0020] In one aspect, the non-contact pad cleaning device further comprises a pad cleaning nozzle forming a jet of a liquid discharge fluid for guiding liquid in the two-fluid on the polishing surface of the polishing pad to the outer periphery of the polishing pad.

[0021] In one aspect, the non-contact pad cleaning device further includes: a liquid discharge fluid line that supplies liquid discharge fluid to the pad cleaning nozzle; and a fine bubble generator that is connected to the liquid discharge fluid line.

[0022] In one aspect, the pad cleaning nozzle is disposed downstream of the plurality of two-fluid nozzles in the rotational direction of the polishing pad.

[0023] In one aspect, the plurality of two-fluid nozzles include a center-side two-fluid nozzle located on the center side of the polishing pad and an outer-periphery-side two-fluid nozzle located on the outer periphery side of the polishing pad, and the distance from the discharge port of the outer-periphery-side two-fluid nozzle to the polishing surface is less than the distance from the discharge port of the center-side two-fluid nozzle to the polishing surface.

[0024] In one aspect, the plurality of two-fluid nozzles include a center-side two-fluid nozzle located on the center side of the polishing pad and an outer-periphery-side two-fluid nozzle located on the outer periphery side of the polishing pad, and the distance from the discharge port of the outer-periphery-side two-fluid nozzle to the polishing surface is greater than the distance from the discharge port of the center-side two-fluid nozzle to the polishing surface.

[0025] In one aspect, the liquid supply line has a plurality of branch liquid lines respectively connected to the plurality of two-fluid nozzles, and the non-contact pad cleaning device further includes: a plurality of liquid flow control valves respectively connected to the plurality of branch liquid lines; and an operation control unit that independently controls the operations of the plurality of liquid flow control valves. The plurality of two-fluid nozzles include a center-side two-fluid nozzle located on the center side of the polishing pad and an outer-periphery-side two-fluid nozzle located on the outer periphery side of the polishing pad, and the operation control unit controls the operations of the plurality of liquid flow control valves such that the flow rate of the liquid supplied to the outer-periphery-side two-fluid nozzle is larger than the flow rate of the liquid supplied to the center-side two-fluid nozzle.

[0026] In one aspect, the liquid supply line has a plurality of branch liquid lines respectively connected to the plurality of two-fluid nozzles, and the non-contact pad cleaning device further includes: a plurality of liquid flow control valves respectively connected to the plurality of branch liquid lines; and an operation control unit that independently controls the operations of the plurality of liquid flow control valves. The plurality of two-fluid nozzles include a center-side two-fluid nozzle located on the center side of the polishing pad and an outer-periphery-side two-fluid nozzle located on the outer periphery side of the polishing pad, and the operation control unit controls the operations of the plurality of liquid flow control valves such that the flow rate of the liquid supplied to the center-side two-fluid nozzle is larger than the flow rate of the liquid supplied to the outer-periphery-side two-fluid nozzle.

[0027] In one mode, the gas supply line has a plurality of branch gas lines respectively connected to the plurality of two-fluid nozzles, and the non-contact pad cleaning device further includes: a plurality of gas flow control valves respectively connected to the plurality of branch gas lines; and an operation control unit that independently controls the operations of the plurality of gas flow control valves. The plurality of two-fluid nozzles include a central two-fluid nozzle located on the central side of the polishing pad and an outer peripheral two-fluid nozzle located on the outer peripheral side of the polishing pad. The operation control unit controls the operations of the plurality of gas flow control valves such that the flow rate of the gas supplied to the outer peripheral two-fluid nozzle is larger than the flow rate of the gas supplied to the central two-fluid nozzle.

[0028] In one mode, the gas supply line has a plurality of branch gas lines respectively connected to the plurality of two-fluid nozzles, and the non-contact pad cleaning device further includes: a plurality of gas flow control valves respectively connected to the plurality of branch gas lines; and an operation control unit that independently controls the operations of the plurality of gas flow control valves. The plurality of two-fluid nozzles include a central two-fluid nozzle located on the central side of the polishing pad and an outer peripheral two-fluid nozzle located on the outer peripheral side of the polishing pad. The operation control unit controls the operations of the plurality of gas flow control valves such that the flow rate of the gas supplied to the central two-fluid nozzle is larger than the flow rate of the gas supplied to the outer peripheral two-fluid nozzle.

[0029] In one mode, the gas supply line has a plurality of branch gas lines respectively connected to the plurality of two-fluid nozzles, and the non-contact pad cleaning device further includes: a plurality of pressure regulators respectively connected to the plurality of branch gas lines; and an operation control unit that independently controls the operations of the plurality of pressure regulators. The plurality of two-fluid nozzles include a central two-fluid nozzle located on the central side of the polishing pad and an outer peripheral two-fluid nozzle located on the outer peripheral side of the polishing pad. The operation control unit controls the operations of the plurality of pressure regulators such that the pressure of the gas supplied to the outer peripheral two-fluid nozzle is higher than the pressure of the gas supplied to the central two-fluid nozzle.

[0030] In one mode, there is provided a non-contact polishing pad cleaning device that cleans the polishing surface of a polishing pad for polishing a workpiece in a non-contact manner, and includes: a rotating table that rotates the polishing pad; a two-fluid nozzle that is arranged above the polishing pad; a liquid supply line and a gas supply line that are connected to the two-fluid nozzle; and a nozzle swing mechanism that swings the two-fluid nozzle along the polishing surface. The ejection port of the two-fluid nozzle faces outward in the radial direction of the polishing pad.

[0031] In one mode, the non-contact pad cleaning device further includes a fine bubble generator connected to the liquid supply line.

[0032] In one mode, the non-contact pad cleaning device further includes a liquid heating device that is connected to the liquid supply line and heats the liquid flowing in the liquid supply line.

[0033] In one mode, the non-contact pad cleaning device further includes a pad cleaning nozzle that forms a jet of liquid discharge fluid, and the pad cleaning nozzle is used to guide the liquid in the two-fluid on the polishing surface of the polishing pad to the outer periphery of the polishing pad.

[0034] In one mode, the non-contact pad cleaning device further includes: a liquid discharge fluid line that supplies liquid discharge fluid to the pad cleaning nozzle; and a fine bubble generator that is connected to the liquid discharge fluid line.

[0035] In one mode, the pad cleaning nozzle is arranged downstream of the two-fluid nozzle in the rotation direction of the polishing pad.

[0036] Advantages of the Invention

[0037] Since the ejection ports of the plurality of two-fluid nozzles are inclined with respect to the reference line extending in the radial direction of the polishing pad, the two-fluid jets ejected from the plurality of ejection ports do not collide with each other and do not obstruct the flow of the liquid on the polishing surface. The liquid contained in the two-fluid jet flows outward by the centrifugal force generated by the rotating polishing pad, and foreign matters such as abrasive grains can be washed off from the polishing pad.

[0038] Since the ejection ports of the plurality of two-fluid nozzles face outward in the radial direction of the polishing pad, the two-fluid jets ejected from the plurality of ejection ports form a liquid flow that faces outward on the polishing surface. The outward flow of the liquid is accelerated by the centrifugal force generated by the rotating polishing pad, and foreign matters such as abrasive grains can be washed off from the polishing pad. Description of the Drawings

[0039] Figure 1 is a schematic diagram showing an embodiment of a polishing apparatus including a non-contact pad cleaning device.

[0040] Figure 2 is a top view showing an embodiment of a plurality of two-fluid nozzles, a pad cleaning nozzle, and a polishing pad as viewed from above.

[0041] Figure 3 is an enlarged view of the two-fluid nozzle.

[0042] Figure 4It is a diagram showing an embodiment of a two-fluid nozzle when a two-fluid jet is ejected.

[0043] Figure 5 It is a diagram explaining the flow of the liquid contained in the two-fluid jet ejected from the two-fluid nozzle.

[0044] Figure 6 It is a diagram showing another embodiment of the configuration of the two-fluid nozzle.

[0045] Figure 7 It is a diagram explaining the tilt angle of the two-fluid nozzle with respect to the polishing surface.

[0046] Figure 8 It is a diagram showing yet another embodiment of the configuration of the two-fluid nozzle.

[0047] Figure 9 It is Figure 8 a perspective view of the two-fluid nozzle shown.

[0048] Figure 10 It is a diagram explaining the flow of the liquid contained in the two-fluid jet ejected from the two-fluid nozzle.

[0049] Figure 11 It is a diagram showing yet another embodiment of the configuration of the two-fluid nozzle.

[0050] Figure 12 It is a schematic diagram showing an embodiment of a structure for supplying liquid and gas to the two-fluid nozzle.

[0051] Figure 13 It is a schematic diagram showing another embodiment of a non-contact pad cleaning device.

[0052] Figure 14 It is a schematic diagram explaining an example of the action of fine bubbles.

[0053] Figure 15 It is a schematic diagram explaining another example of the action of fine bubbles.

[0054] Figure 16 It is a schematic diagram showing yet another embodiment of a non-contact pad cleaning device.

[0055] Figure 17 It is a schematic diagram showing yet another embodiment of a non-contact pad cleaning device.

[0056] Figure 18 It is a schematic diagram showing yet another embodiment of a non-contact pad cleaning device.

[0057] Figure 19 It is a schematic diagram showing yet another embodiment of a non-contact pad cleaning device.

[0058] Figure 20 It is a schematic view showing another embodiment of a non-contact pad cleaning device.

[0059] Figure 21 It is a schematic view showing another embodiment of a non-contact pad cleaning device.

[0060] Figure 22 It is a schematic view showing another embodiment of a non-contact pad cleaning device.

[0061] Figure 23 is Figure 22 A top view of the dual-fluid liquid nozzle and the pad cleaning nozzle shown.

[0062] Figure 24 is from Figure 22 A view of the dual-fluid nozzle observed from the direction indicated by arrow A in.

[0063] Explanation of symbols

[0064] 2 Grinding pad

[0065] 2a Grinding surface

[0066] 5 Rotary table

[0067] 5a Table shaft

[0068] 7 Grinding head

[0069] 8 Dual-fluid nozzle

[0070] 8a Nozzle outlet

[0071] 9 Pad cleaning nozzle

[0072] 10 Grinding fluid supply nozzle

[0073] 14 Support shaft

[0074] 16 Grinding head swing arm

[0075] 18 Grinding head shaft

[0076] 21 Table rotation motor

[0077] 22 Nozzle bracket

[0078] 30 Action control unit

[0079] 32 Support pillar

[0080] 35 Nozzle holding part

[0081] 50 Truing tool

[0082] 51 Truing disk

[0083] 51a Truing surface

[0084] 52 Trimmer shaft

[0085] 55 Trimmer swing arm

[0086] 58 Support shaft

[0087] 61 Liquid supply line

[0088] 62 Branch liquid line

[0089] 65 Gas supply line

[0090] 66 Branch gas line

[0091] 71 Liquid flow control valve

[0092] 73 Gas flow control valve

[0093] 75 Pressure regulator

[0094] 78 Fine bubble generator

[0095] 80 Liquid discharge fluid line

[0096] 83 Liquid heating device

[0097] 87 Ultrasonic generator

[0098] 90 Nozzle swing mechanism. Detailed implementation mode

[0099] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a schematic diagram showing an embodiment of a polishing apparatus having a non-contact pad cleaning device. The polishing apparatus is a device for chemically mechanically polishing a wafer W, which is an example of a workpiece used in the manufacture of semiconductor devices. As Figure 1 shown, the polishing apparatus includes: a rotating table 5 that supports a polishing pad 2 having a polishing surface 2a; a polishing head 7 that presses the wafer W against the polishing surface 2a; a polishing liquid supply nozzle 10 that supplies a polishing liquid (for example, a slurry containing abrasive grains) to the polishing surface 2a; and a plurality of two-fluid nozzles 8 and a plurality of pad cleaning nozzles 9 that clean the polishing surface 2a of the polishing pad 2. The plurality of two-fluid nozzles 8 and the plurality of pad cleaning nozzles 9 are arranged above the polishing surface 2a of the polishing pad 2 and face the polishing surface 2a.

[0100] The polishing head 7 is configured to be able to hold the wafer W on its lower surface. The wafer W has a film to be polished. Although a wafer is used as an example of the workpiece in the following embodiments, the workpiece is not limited to a wafer, and may also be a circular substrate, a rectangular substrate, a panel, etc. used in the manufacture of semiconductor devices.

[0101] The polishing apparatus further includes a support shaft 14, a polishing head swing arm 16 connected to the upper end of the support shaft 14, and a polishing head shaft 18 rotatably supported at the free end of the polishing head swing arm 16. The polishing head 7 is fixed to the lower end of the polishing head shaft 18. A polishing head rotation mechanism (not shown) including a motor or the like is disposed within the polishing head swing arm 16. The polishing head rotation mechanism is connected to the polishing head shaft 18 and configured to rotate the polishing head shaft 18 and the polishing head 7 in the direction indicated by the arrow.

[0102] The polishing head shaft 18 is connected to a polishing head lifting mechanism (including a ball screw mechanism or the like) not shown. The polishing head lifting mechanism is configured to move the polishing head shaft 18 relative to the polishing head swing arm 16 up and down. By the up and down movement of the polishing head shaft 18, as indicated by the arrow, the polishing head 7 can move up and down relative to the polishing head swing arm 16 and the rotary table 5.

[0103] The polishing apparatus further includes a table rotation motor 21 that rotates the polishing pad 2 and the rotary table 5 about their axes. The table rotation motor 21 is disposed below the rotary table 5, and the rotary table 5 is connected to the table rotation motor 21 via a table shaft 5a. The rotary table 5 and the polishing pad 2 are rotated in the direction indicated by the arrow about the table shaft 5a by the table rotation motor 21. The polishing pad 2 is adhered to the upper surface of the rotary table 5. The exposed surface of the polishing pad 2 constitutes a polishing surface 2a for polishing the wafer W.

[0104] The polishing of the wafer W is performed as follows. The wafer W is held by the polishing head 7 with its polished surface facing downward. While rotating the polishing head 7 and the rotary table 5 respectively, a polishing liquid (for example, a slurry containing abrasive grains) is supplied from a polishing liquid supply nozzle 10 provided above the rotary table 5 onto the polishing surface 2a of the polishing pad 2. The polishing pad 2 rotates integrally with the rotary table 5 about its central axis. The polishing head 7 is moved to a predetermined height by a polishing head lifting mechanism (not shown). In addition, while maintaining the above-mentioned predetermined height, the polishing head 7 presses the wafer W against the polishing surface 2a of the polishing pad 2. The wafer W rotates integrally with the polishing head 7. In a state where the polishing liquid exists on the polishing surface 2a of the polishing pad 2, the wafer W is in sliding contact with the polishing surface 2a. The surface of the wafer W is polished by a combination of 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 2.

[0105] The polishing apparatus includes a dresser 50 for dressing the polishing surface 2a of the polishing pad 2. The dresser 50 includes a dressing disk 51 that slides in contact with the polishing surface 2a of the polishing pad 2, a dresser shaft 52 connected to the dressing disk 51, and a dresser swing arm 55 that rotatably supports the dresser shaft 52. The lower surface of the dressing disk 51 constitutes a dressing surface 51a, which is composed of abrasive grains (for example, diamond particles).

[0106] The dresser shaft 52 is connected to a disk pressing mechanism (including, for example, a cylinder) (not shown) disposed within the dresser swing arm 55. This disk pressing mechanism presses the dressing surface 51a of the dressing disk 51 against the polishing surface 2a of the polishing pad 2 via the dresser shaft 52. Further, the dresser shaft 52 is connected to a disk rotation mechanism (including, for example, a motor) (not shown) disposed within the dresser swing arm 55. This disk rotation mechanism rotates the dressing disk 51 in the direction indicated by the arrow via the dresser shaft 52.

[0107] The polishing surface 2a of the polishing pad 2 is dressed as follows. The polishing pad 2 and the turntable 5 are rotated together by the table rotation motor 21. While the dressing disk 51 rotates about the dresser shaft 52 using a disk rotation mechanism (not shown), the dressing surface 51a of the dressing disk 51 is pressed against the polishing surface 2a by a disk pressing mechanism (not shown) and slides in contact with the polishing surface 2a. During the rotation of the dressing disk 51, the dresser swing arm 55 swings about the support shaft 58, so that the dressing disk 51 swings in the radial direction of the polishing surface 2a. In this way, the polishing pad 2 is slightly cut by the dressing disk 51, and the polishing surface 2a is dressed (regenerated). The dressing of the polishing surface 2a of the polishing pad 2 is performed during or after the polishing of the wafer W.

[0108] A plurality of two-fluid nozzles 8 are arranged above the polishing pad 2 along the radial direction of the polishing pad 2. Each two-fluid nozzle 8 forms a two-fluid jet flow composed of a mixed fluid of a liquid and a gas, and ejects the two-fluid jet flow onto the polishing surface 2a of the polishing pad 2. The plurality of two-fluid nozzles 8 and the plurality of pad cleaning nozzles 9 are held by the nozzle bracket 22. The nozzle bracket 22 is fixed to the support column 32.

[0109] The plurality of pad cleaning nozzles 9 are arranged along the radial direction of the polishing pad 2, and eject a liquid discharge fluid jet flow onto the polishing surface 2a of the polishing pad 2. The plurality of pad cleaning nozzles 9 are arranged downstream of the plurality of two-fluid nozzles 8 in the rotation direction of the polishing pad 2.

[0110] The plurality of two-fluid nozzles 8 and the pad cleaning nozzles 9 simultaneously eject a two-fluid jet flow and a liquid discharge fluid jet flow onto the polishing surface 2a of the polishing pad 2 to clean the polishing surface 2a. The cleaning of the polishing surface 2a of the polishing pad 2 is performed after the wafer W is polished and before the next wafer is polished. The cleaning of the polishing pad 2 using the two-fluid nozzles 8 and the pad cleaning nozzles 9 (hereinafter sometimes referred to as the pad cleaning operation) can be performed before or after the dressing of the polishing pad 2 using the dresser (hereinafter sometimes referred to as the dressing operation), or can be performed during the dressing operation.

[0111] For example, a dressing operation can be performed after grinding the wafer W, followed by a pad cleaning operation. In another example, the dressing operation and the pad cleaning operation can be performed simultaneously after grinding the wafer W. In yet another example, the dressing operation can be performed while grinding the wafer W, and after the grinding and dressing operations of the wafer W, the pad cleaning operation is performed. The time of the pad cleaning operation, that is, the cleaning time of the polishing pad 2 using the two-fluid nozzle 8 and the pad cleaning nozzle 9 can be set arbitrarily.

[0112] The grinding apparatus includes an operation control unit 30 that controls the operations of the grinding apparatus, and the operations of the grinding apparatus include the grinding operation, the dressing operation, and the pad cleaning operation of the wafer W. The operation control unit 30 is composed of at least one computer. The operation control unit 30 includes a storage device 30a that stores programs and a processing device 30b that performs calculations according to commands included in the programs. The storage device 30a has a main storage device such as a random access memory (RAM) and auxiliary storage devices such as a hard disk drive (HDD) and a solid state drive (SSD). As an example of the processing device 30b, a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit) can be cited. However, the specific structure of the operation control unit 30 is not limited to these examples.

[0113] In Figure 1 the embodiment shown, the non-contact pad cleaning device for non-contact cleaning of the polishing surface 2a of the polishing pad 2 includes a plurality of two-fluid nozzles 8, a pad cleaning nozzle 9, and a turntable 5. When the flow rate of the liquid contained in the two-fluid jet ejected from the two-fluid nozzle 8 is high enough, the pad cleaning nozzle 9 may sometimes not be provided. The turntable 5 forms a part of the non-contact pad cleaning device, but at the same time also forms Figure 1 a part of the grinding apparatus shown.

[0114] Figure 2 is a top view of an embodiment of a plurality of two-fluid nozzles 8, a pad cleaning nozzle 9, and a polishing pad 2. In Figure 2 the embodiment shown, the polishing pad 2 rotates in the direction indicated by the arrow (counterclockwise in the example of Figure 2 ). The plurality of two-fluid nozzles 8 are fixed to the nozzle bracket 22 by the nozzle holding portion 35. The pad cleaning nozzles 9 are arranged in the radial direction of the polishing pad 2. These pad cleaning nozzles 9 are arranged toward the radially outer side of the polishing pad 2, and a flow of liquid discharged toward the radially outer side is formed on the polishing surface 2a of the polishing pad 2.

[0115] In Figure 2 the embodiment shown, four two-fluid nozzles 8 are arranged in the radial direction of the polishing pad 2. However, the number of the two-fluid nozzles 8 is not limited to this embodiment, and two or three two-fluid nozzles 8, or five or more two-fluid nozzles 8 can also be provided.

[0116] In the present embodiment, the positions of the plurality of two-fluid nozzles 8 and the pad cleaning nozzle 9 are fixed and are always located above the polishing pad 2. In one embodiment, the plurality of two-fluid nozzles 8 may be configured to be away from the pad cleaning nozzle 9. For example, the plurality of two-fluid nozzles 8 may be held by a nozzle holding portion or a nozzle bracket (not shown) away from the pad cleaning nozzle 9. In this case, the pad cleaning nozzle 9 is also arranged downstream of the two-fluid nozzles 8 in the rotational direction of the polishing pad 2. Each two-fluid nozzle 8 is a fan-shaped nozzle configured to form a fan-shaped two-fluid jet. Each two-fluid nozzle 8 has a jet outlet 8a at its bottom for ejecting the two-fluid jet.

[0117] As Figure 2 shown, when viewed from a direction perpendicular to the polishing surface 2a of the polishing pad 2, the jet outlets 8a of the plurality of two-fluid nozzles 8 are inclined with respect to a reference line RL extending in the radial direction of the polishing pad 2. The reference line RL is an imaginary straight line passing through the center Cr of the polishing pad 2 and extending in the radial direction of the polishing pad 2. In the present embodiment, when viewed from a direction perpendicular to the polishing surface 2a of the polishing pad 2, the jet outlets 8a of the plurality of two-fluid nozzles 8 are located on the reference line RL.

[0118] Figure 3 is an enlarged view of the two-fluid nozzle 8. The jet outlet 8a of each two-fluid nozzle 8 is inclined with respect to the reference line RL at a prescribed angle α. More specifically, the jet outlet 8a of each two-fluid nozzle 8 is inclined in the same direction as the rotational direction of the polishing pad 2. In Figure 3 the shown embodiment, since the polishing pad 2 rotates in the counterclockwise direction, when viewed from above, the jet outlets 8a of each two-fluid nozzle 8 are also inclined in the counterclockwise direction with respect to the reference line RL. The jet outlets 8a of the four two-fluid nozzles 8 are inclined at the same angle, but they may also be inclined at different angles. For example, the inclination angle α of the jet outlets 8a of the four two-fluid nozzles 8 with respect to the reference line RL may increase as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases.

[0119] As Figure 2 shown, the jet outlets 8a of the plurality of two-fluid nozzles 8 are arranged at equal intervals from the center Cr to the outer periphery of the polishing pad 2. Therefore, when the polishing pad 2 rotates, the two-fluid nozzles 8 can direct the two-fluid jets to the entire polishing surface 2a of the polishing pad 2.

[0120] Figure 4 is a view showing an embodiment of the two-fluid nozzle 8 when ejecting the two-fluid jet, Figure 5 is a view for explaining the flow of the liquid contained in the two-fluid jet ejected from the two-fluid nozzle 8. The fan-shaped two-fluid jets ejected from the plurality of two-fluid nozzles 8 do not collide with each other but collide with the polishing surface 2a of the polishing pad 2. Figure 5The dashed lines of the ellipse shown indicate the area where the two-fluid jet collides with the polishing surface 2a (hereinafter referred to as the collision area). These collision areas are inclined with respect to the reference line RL and are arranged on the reference line RL.

[0121] The two-fluid jet can remove foreign substances (for example, abrasive grains of the slurry, abrasive debris such as reaction by-products generated when polishing the wafer, and debris of the polishing pad 2 generated during the dressing operation) from the minute holes formed on the polishing surface 2a of the polishing pad 2. The liquid contained in the two-fluid jet forms a liquid flow on the polishing surface 2a after the two-fluid jet collides with the polishing surface 2a of the polishing pad 2. As Figure 5 shown, since the polishing pad 2 rotates in the direction indicated by the arrow, due to the centrifugal force and the friction between the polishing pad 2 and the liquid, the liquid flows toward the outer side of the polishing pad 2 and in the rotation direction of the polishing pad 2. Such a liquid flow can wash away the foreign substances discharged from the holes of the polishing pad 2 from the polishing pad 2. In addition, the flow of the liquid discharge fluid indicated by the thick white arrow can enhance the effect of discharging the liquid contained in the two-fluid jet and the foreign substances contained in the liquid from the polishing pad 2.

[0122] Figure 6 is a diagram showing another embodiment of the configuration of the two-fluid nozzle 8. As Figure 6 shown, it can be that each two-fluid nozzle 8 is inclined with respect to the polishing surface 2a in such a way that the two-fluid jet is ejected to the radially outer side of the polishing pad 2. Each two-fluid nozzle 8 is inclined in such a way that the ejection port 8a of each two-fluid nozzle 8 faces the radially outer side of the polishing pad 2. Since the two-fluid nozzle 8 can form a liquid flow flowing toward the radially outer side, it is easy to discharge foreign substances from the polishing pad 2.

[0123] Figure 7 is a diagram for explaining the inclination angle of the two-fluid nozzle 8 with respect to the polishing surface 2a. The inclination angle θ of each two-fluid nozzle 8 with respect to the direction perpendicular to the polishing surface 2a is greater than 0 degree and less than or equal to 60 degrees. More preferably, the inclination angle θ of each two-fluid nozzle 8 is in the range of 15 to 30 degrees. A plurality of two-fluid nozzles 8 can be inclined with respect to the polishing surface 2a at different angles. In one embodiment, the ejection port 8a of each two-fluid nozzle 8 faces the radially outer side of the polishing pad 2, and each two-fluid nozzle 8 is inclined with respect to the polishing surface 2a in such a way that it faces the downstream side in the rotation direction of the polishing pad 2. Since the two-fluid nozzle 8 can form a liquid flow flowing toward the radially outer side, it is easy to discharge foreign substances from the polishing pad 2.

[0124] Figure 8 is a diagram showing still another embodiment of the configuration of the two-fluid nozzle 8. In Figure 8In the figure, illustrations of the pad cleaning nozzle 9, the nozzle bracket 22, and the nozzle holding portion 35 are omitted. When viewed from a direction perpendicular to the polishing surface 2a of the polishing pad 2, the inclination angle of the ejection ports 8a of the plurality of two-fluid nozzles 8 with respect to the reference line RL increases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases. The inclination angle of the ejection port 8a of each two-fluid nozzle 8 with respect to the reference line RL corresponds to the angle α described with reference to Figure 3 is described.

[0125] In addition, when viewed from a direction perpendicular to the polishing surface 2a of the polishing pad 2, the distance L of the ejection ports 8a of the plurality of two-fluid nozzles 8 from the reference line RL increases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases. The distance L of the ejection port 8a of each two-fluid nozzle 8 from the reference line RL is the distance from the reference line RL toward the downstream side in the rotation direction of the polishing pad 2.

[0126] Although not illustrated, the plurality of two-fluid nozzles 8 can be fixed to the nozzle bracket 22 through the nozzle holding portion 35 (refer to Figure 2 ), or the pad cleaning nozzle 9 can also be arranged away from the plurality of two-fluid nozzles 8.

[0127] Figure 9 is Figure 8 a perspective view of the two-fluid nozzle 8 shown in Figure 10 is a diagram for explaining the flow of the liquid contained in the two-fluid jet ejected from the two-fluid nozzle 8. The fan-shaped two-fluid jets ejected from the plurality of two-fluid nozzles 8 collide with the polishing surface 2a of the polishing pad 2. Figure 10 The elliptical dotted lines shown in

[0128] indicate the collision regions where the two-fluid jets collide with the polishing surface 2a. These collision regions are inclined with respect to the reference line RL and are connected by drawing arcs from the center Cr to the outer periphery of the polishing pad 2. The liquids constituting the two-fluid jets ejected from each two-fluid nozzle 8 merge with the liquids constituting the two-fluid jets ejected from other two-fluid nozzles 8, forming a strong flow of liquid from the center Cr of the polishing pad 2 toward the outer periphery. This liquid flow can wash away foreign substances discharged from the holes of the polishing pad 2 from the polishing pad 2. In addition, the flow of the liquid discharge fluid indicated by the thick white arrow can enhance the action of discharging the liquid contained in the two-fluid jet and the foreign substances contained in this liquid from the polishing pad 2.

[0129] In one embodiment, as Figure 11As shown, each two-fluid nozzle 8 is inclined with respect to the polishing surface 2a in such a manner that the two-fluid jet is ejected to the radially outer side of the polishing pad 2. A plurality of two-fluid nozzles 8 can be inclined at different angles with respect to the polishing surface 2a. Each two-fluid nozzle 8 is inclined in such a manner that the ejection port 8a of each two-fluid nozzle 8 faces the radially outer side of the polishing pad 2. The inclination angle of each two-fluid nozzle 8 with respect to the direction perpendicular to the polishing surface 2a is greater than 0 degree and less than or equal to 60 degrees, and more preferably, the inclination angle of each two-fluid nozzle 8 is in the range of 15 to 30 degrees. In one embodiment, the ejection port 8a of each two-fluid nozzle 8 inclines each two-fluid nozzle 8 with respect to the polishing surface 2a in such a manner that it faces the radially outer side of the polishing pad 2 and faces the downstream side in the rotational direction of the polishing pad 2. Since the two-fluid nozzle 8 can form a liquid flow flowing radially outward, it is easy to discharge foreign matter from the polishing pad 2.

[0130] Examples of the liquid supplied to the two-fluid nozzle 8 and the liquid discharge fluid supplied to the pad cleaning nozzle 9 include pure water and pure water containing fine bubbles. Examples of the gas supplied to the two-fluid nozzle 8 include air and an inert gas (e.g., nitrogen).

[0131] Figure 12 is a schematic diagram showing one embodiment of a structure for supplying a liquid and a gas to the two-fluid nozzle 8. The non-contact type pad cleaning device includes a liquid supply line 61 and a gas supply line 65 connected to a plurality of two-fluid nozzles 8. The liquid supply line 61 is connected to a liquid supply source (e.g., a pure water supply source) not shown, and the gas supply line 65 is connected to a gas supply source (e.g., an air supply source or an inert gas supply source) not shown.

[0132] The liquid supply line 61 includes a plurality of branch liquid lines 62, and the gas supply line 65 includes a plurality of branch gas lines 66. A plurality of two-fluid nozzles 8 are respectively connected to the plurality of branch liquid lines 62 and are also respectively connected to the plurality of branch gas lines 66.

[0133] The non-contact type pad cleaning device includes a liquid flow control valve 71 disposed in the liquid supply line 61, a gas flow control valve 73 disposed in the gas supply line 65, and a pressure regulator 75. The liquid flow control valve 71 is configured to adjust the flow rate of the liquid supplied to the plurality of two-fluid nozzles 8. The gas flow control valve 73 is configured to adjust the flow rate of the gas supplied to the plurality of two-fluid nozzles 8. The pressure regulator 75 is configured to adjust the pressure of the gas supplied to the plurality of two-fluid nozzles 8. The liquid flow control valve 71, the gas flow control valve 73, and the pressure regulator 75 are electrically connected to the operation control unit 30, and the operations of the liquid flow control valve 71, the gas flow control valve 73, and the pressure regulator 75 are controlled by the operation control unit 30.

[0134] Liquids and gases are supplied to each two-fluid nozzle 8 through a liquid supply line 61 and a gas supply line 65, and are mixed within each two-fluid nozzle 8. Then, the mixed fluid of the liquid and the gas is ejected as a two-fluid jet from the ejection port 8a of each two-fluid nozzle 8.

[0135] Figure 13 It is a schematic diagram showing another embodiment of the non-contact pad cleaning device. The structure of this embodiment not specifically described is the same as the embodiment described with reference to Figure 12 and thus the repeated description thereof is omitted. As Figure 13 shown, the non-contact pad cleaning device of this embodiment further includes a fine bubble generator 78 connected to the liquid supply line 61. Liquids such as pure water are first supplied to the fine bubble generator 78, and a liquid containing fine bubbles (microbubbles) is generated by the fine bubble generator 78. The structure of the fine bubble generator 78 is not particularly limited, and a commercially available fine bubble generator can be used. The liquid containing fine bubbles is supplied to the two-fluid nozzle 8 through the liquid supply line 61. The two-fluid nozzle 8 ejects a two-fluid jet including fine bubbles onto the polishing pad 2.

[0136] Figure 14 It is a schematic diagram showing an example of the action of fine bubbles. The fine bubbles 400 are usually negatively charged. Foreign matters 500 such as abrasive debris are surrounded by the fine bubbles 400 present in the liquid. On the other hand, the fine bubbles 400 adhere to the polishing surface 2a of the polishing pad 2. Since the fine bubbles 400 surrounding the foreign matter 500 and the fine bubbles 400 surrounding other foreign matters 500 repel each other by the negative charge, the foreign matters 500 can be prevented from adhering to each other. Furthermore, since the fine bubbles 400 are present on the polishing surface 2a, the fine bubbles 400 surrounding the foreign matter 500 and the fine bubbles 400 on the polishing surface 2a repel each other, and the foreign matter 500 can be prevented from adhering to the polishing surface 2a again.

[0137] Figure 15 It is a schematic diagram showing another example of the action of fine bubbles. Minute foreign matters 500 adhere to the fine bubbles 400, and the foreign matters 500 and the fine bubbles 400 are discharged from the polishing pad 2 by the flow of the liquid.

[0138] In one embodiment, as Figure 16 shown, the fine bubble generator 78 can be connected to a liquid discharge fluid line 80 instead of or as a supplement to the liquid supply line 61, and the liquid discharge fluid line 80 supplies liquid discharge fluid to a plurality of pad cleaning nozzles 9. The liquid discharge fluid line 80 is connected to the plurality of pad cleaning nozzles 9. The liquid discharge fluid containing fine bubbles is supplied to the pad cleaning nozzle 9 through the liquid discharge fluid line 80. The pad cleaning nozzle 9 ejects a jet of the liquid discharge fluid containing fine bubbles onto the polishing pad 2. In this embodiment, the same effects as those described with reference toFigure 14 and Figure 15 the effect of the fine bubbles described.

[0139] Figure 17 is a schematic diagram showing another embodiment of the non-contact pad cleaning device. The structure of this embodiment not particularly described is the same as the embodiment described with reference to Figure 13 so the repeated description thereof is omitted. As Figure 17 shown, the non-contact pad cleaning device of this embodiment further includes a liquid heating device 83 connected to the liquid supply line 61. The liquid heating device 83 is configured to heat the liquid flowing through the liquid supply line 61. Specifically, the liquid heating device 83 is configured to heat the liquid flowing in the liquid supply line 61 to a temperature within the range of 20°C to 100°C. The specific structure of the liquid heating device 83 is not particularly limited. For example, an electric heater or the like can be used in the liquid heating device 83.

[0140] The heated liquid is supplied to the two-fluid nozzle 8 through the liquid supply line 61. The two-fluid nozzle 8 ejects a two-fluid jet containing the heated liquid onto the polishing pad 2. The temperature of the polishing pad 2 rises due to the heated liquid, and the polishing pad 2 becomes soft. As a result, the two-fluid jet becomes more likely to remove foreign matter from the holes of the polishing pad 2. The liquid heating device 83 can be applied to each of the embodiments described with reference to Figures 1 to 16 so the repeated description thereof is omitted. As

[0141] Figure 18 is a schematic diagram showing another embodiment of the non-contact pad cleaning device. The structure of this embodiment not particularly described is the same as the embodiment described with reference to Figure 13 so the repeated description thereof is omitted. As Figure 18 shown, the distance from the jet outlet 8a of the two-fluid nozzle 8 located on the outer peripheral side of the polishing pad 2 to the polishing surface 2a is smaller than the distance from the jet outlet 8a of the two-fluid nozzle 8 located on the central side of the polishing pad 2 to the polishing surface 2a. This is for the following reason. That is, as the distance from the center Cr of the polishing pad 2 increases, the circumferential length on the polishing surface 2a of the polishing pad 2 increases. Therefore, compared with the two-fluid nozzle 8 located on the central side of the polishing pad 2, the two-fluid nozzle 8 located on the outer peripheral side of the polishing pad 2 requires a higher cleaning ability.

[0142] According to this embodiment, since the jet outlet 8a of the two-fluid nozzle 8 located on the outer peripheral side of the polishing pad 2 is arranged closer to the polishing surface 2a, the cleaning effect of the outer peripheral region of the polishing surface 2a of the polishing pad 2 can be improved. In one embodiment, as Figure 18As shown, the distance between the discharge ports 8a of the plurality of two-fluid nozzles 8 and the polishing surface 2a can decrease as the distance between each two-fluid nozzle 8 and the center Cr of the polishing pad 2 increases. With the two-fluid nozzles 8 configured in this way, the entire polishing surface 2a of the polishing pad 2 can be cleaned uniformly. Refer to Figure 18 the configuration of the two-fluid nozzle 8 described can be applied to each of the embodiments described with reference to Figures 1 to 17 the embodiments.

[0143] In another embodiment, as Figure 19 shown, the distance between the discharge port 8a of the two-fluid nozzle 8 located on the outer peripheral side of the polishing pad 2 and the polishing surface 2a is greater than the distance between the discharge port 8a of the two-fluid nozzle 8 located on the center side of the polishing pad 2 and the polishing surface 2a. This is for the following reason. That is, the area to be cleaned on the outer peripheral side of the polishing surface 2a of the polishing pad 2 is larger than that on the center side. Since the discharge port 8a of the two-fluid nozzle 8 located on the outer peripheral side of the polishing pad 2 is far from the polishing surface 2a, the two-fluid jet expands along its traveling direction, and a wider area can be cleaned.

[0144] In one embodiment, as Figure 19 shown, the distance between the discharge ports 8a of the plurality of two-fluid nozzles 8 and the polishing surface 2a can also increase as the distance between each two-fluid nozzle 8 and the center Cr of the polishing pad 2 increases. Refer to Figure 19 the configuration of the two-fluid nozzle 8 described can be applied to each of the embodiments described with reference to Figures 1 to 17 the embodiments.

[0145] Figure 20 is a schematic diagram showing another embodiment of the non-contact pad cleaning device. The structure of this embodiment not specifically described is the same as that of the embodiment described with reference to Figure 13 the embodiments, and thus its repeated description is omitted. As Figure 20 shown, the non-contact pad cleaning device further includes a plurality of ultrasonic generators 87 respectively installed on the plurality of two-fluid nozzles 8. These ultrasonic generators 87 are electrically connected to the operation control unit 30, and the operation of the ultrasonic generators 87 is controlled by the operation control unit 30.

[0146] The plurality of ultrasonic generators 87 are configured to apply ultrasonic waves to the two-fluid jets ejected from the plurality of two-fluid nozzles 8. The frequency of the ultrasonic waves is selected from the range of 100 kHz to 3.0 MHz. The operation control unit 30 issues commands to each ultrasonic generator 87 to generate ultrasonic waves of a preselected frequency. The plurality of ultrasonic generators 87 can generate ultrasonic waves of the same frequency or different frequencies.

[0147] In one embodiment, the operation control unit 30 controls the operations of the plurality of ultrasonic generators 87 such that the frequency of the ultrasonic wave applied to the two-fluid jet ejected from the two-fluid nozzle 8 disposed on the outer peripheral side of the polishing pad 2 is lower than the frequency of the ultrasonic wave applied to the two-fluid jet ejected from the two-fluid nozzle 8 disposed on the central side of the polishing pad 2. Generally, when the frequency of the ultrasonic wave applied to the two-fluid jet is decreased, the cleaning ability of the two-fluid jet is improved. According to the present embodiment, the cleaning effect of the outer peripheral region of the polishing surface 2a of the polishing pad 2 can be improved.

[0148] In one embodiment, the operation control unit 30 controls the operations of the plurality of ultrasonic generators 87 such that the frequency of the ultrasonic wave applied to the two-fluid jet ejected from each of the plurality of two-fluid nozzles 8 decreases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases. The two-fluid nozzle 8 incorporating the ultrasonic generator 87 controlled in this way can uniformly clean the entire polishing surface 2a of the polishing pad 2.

[0149] Figure 21 FIG. is a schematic view showing still another embodiment of the non-contact pad cleaning device. The structure of the present embodiment not particularly described is the same as that of the embodiment described with reference to Figure 15 and thus the repeated description thereof is omitted. The non-contact pad cleaning device includes a plurality of liquid flow control valves 71 respectively connected to a plurality of branch liquid lines 62, a plurality of gas flow control valves 73 respectively connected to a plurality of branch gas lines 66, and a plurality of pressure regulators 75 respectively connected to a plurality of branch gas lines 66.

[0150] The plurality of liquid flow control valves 71 are respectively connected to the plurality of two-fluid nozzles 8 via a liquid supply line 61. The plurality of gas flow control valves 73 are respectively connected to the plurality of two-fluid nozzles 8 via a gas supply line 65. The plurality of pressure regulators 75 are also respectively connected to the plurality of two-fluid nozzles 8 via the gas supply line 65.

[0151] The plurality of liquid flow control valves 71 can independently adjust the flow rate of the liquid supplied to the plurality of two-fluid nozzles 8. The plurality of gas flow control valves 73 can independently adjust the flow rate of the gas supplied to the plurality of two-fluid nozzles 8. The plurality of pressure regulators 75 can independently adjust the pressure of the gas supplied to the plurality of two-fluid nozzles 8. The plurality of liquid flow control valves 71, the plurality of gas flow control valves 73, and the plurality of pressure regulators 75 are electrically connected to the operation control unit 30, and the operations of the plurality of liquid flow control valves 71, the plurality of gas flow control valves 73, and the plurality of pressure regulators 75 are controlled by the operation control unit 30. The fine bubble generator 78 is disposed upstream of the plurality of liquid flow control valves 71.

[0152] In one embodiment, the motion control unit 30 controls the operations of the plurality of liquid flow control valves 71 such that the flow rate of the liquid supplied to the two-fluid nozzle 8 disposed on the outer peripheral side of the polishing pad 2 is larger than the flow rate of the liquid supplied to the two-fluid nozzle 8 disposed on the central side of the polishing pad 2. The two-fluid nozzle 8 disposed on the outer peripheral side of the polishing pad 2 can strike a stronger two-fluid jet against the outer peripheral surface of the polishing surface 2a of the polishing pad 2 than the two-fluid nozzle 8 disposed on the central side of the polishing pad 2. According to this embodiment, the cleaning effect of the outer peripheral region of the polishing surface 2a of the polishing pad 2 can be improved.

[0153] In one embodiment, the motion control unit 30 controls the operations of the plurality of liquid flow control valves 71 such that the flow rate of the liquid supplied to the plurality of two-fluid nozzles 8 increases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases. By controlling the flow rate of the liquid in this way, the two-fluid nozzles 8 can uniformly clean the entire polishing surface 2a of the polishing pad 2.

[0154] In another embodiment, the motion control unit 30 controls the operations of the plurality of liquid flow control valves 71 such that the flow rate of the liquid supplied to the two-fluid nozzle 8 disposed on the central side of the polishing pad 2 is larger than the flow rate of the liquid supplied to the two-fluid nozzle 8 disposed on the outer peripheral side of the polishing pad 2. The slurry adhering to the central portion of the polishing pad 2 has to move a longer distance outside the polishing pad 2 than the slurry adhering to the outer peripheral portion of the polishing pad 2. Therefore, in this embodiment, in order to improve the dischargeability of the liquid at the central portion of the polishing pad 2, the flow rate of the liquid of the two-fluid nozzle 8 on the central side is made larger than the flow rate of the liquid of the two-fluid nozzle 8 on the outer peripheral side.

[0155] In one embodiment, the motion control unit 30 controls the operations of the plurality of liquid flow control valves 71 such that the flow rate of the liquid supplied to the plurality of two-fluid nozzles 8 decreases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases.

[0156] In one embodiment, the motion control unit 30 controls the operations of the plurality of gas flow control valves 73 such that the flow rate of the gas supplied to the two-fluid nozzle 8 disposed on the outer peripheral side of the polishing pad 2 is larger than the flow rate of the gas supplied to the two-fluid nozzle 8 disposed on the central side of the polishing pad 2. The two-fluid nozzle 8 disposed on the outer peripheral side of the polishing pad 2 can strike a stronger two-fluid jet against the outer peripheral surface of the polishing surface 2a of the polishing pad 2 than the two-fluid nozzle 8 disposed on the central side of the polishing pad 2. According to this embodiment, the cleaning effect of the outer peripheral region of the polishing surface 2a of the polishing pad 2 can be improved.

[0157] In one embodiment, the motion control unit 30 controls the operations of the plurality of gas flow control valves 73 such that the flow rate of the gas supplied to the plurality of two-fluid nozzles 8 increases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases. By controlling the gas flow rate in this way, the two-fluid nozzles 8 can uniformly clean the entire polishing surface 2a of the polishing pad 2.

[0158] In another embodiment, the motion control unit 30 controls the operations of the plurality of gas flow control valves 73 such that the flow rate of the gas supplied to the two-fluid nozzles 8 arranged on the center side of the polishing pad 2 is larger than the flow rate of the gas supplied to the two-fluid nozzles 8 arranged on the outer peripheral side of the polishing pad 2. The slurry adhering to the central portion of the polishing pad 2 has to move a longer distance outside the polishing pad 2 compared to the slurry adhering to the outer peripheral portion of the polishing pad 2. Therefore, in the present embodiment, in order to improve the liquid dischargeability at the central portion of the polishing pad 2, the gas flow rate of the two-fluid nozzles 8 on the center side is made larger than the gas flow rate of the two-fluid nozzles 8 on the outer peripheral side.

[0159] In one embodiment, the motion control unit 30 controls the operations of the plurality of gas flow control valves 73 such that the flow rate of the gas supplied to the plurality of two-fluid nozzles 8 decreases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases.

[0160] In one embodiment, the motion control unit 30 controls the operations of the plurality of pressure regulators 75 such that the pressure of the gas supplied to the two-fluid nozzles 8 arranged on the outer peripheral side of the polishing pad 2 is higher than the pressure of the gas supplied to the two-fluid nozzles 8 arranged on the center side of the polishing pad 2. It is possible to make the two-fluid nozzle 8 arranged on the outer peripheral side of the polishing pad 2 hit the outer peripheral surface of the polishing surface 2a of the polishing pad 2 with a stronger two-fluid jet compared to the two-fluid nozzle 8 arranged on the center side of the polishing pad 2. According to the present embodiment, the cleaning effect of the outer peripheral region of the polishing surface 2a of the polishing pad 2 can be improved.

[0161] In one embodiment, the motion control unit 30 controls the operations of the plurality of pressure regulators 75 such that the pressure of the gas supplied to the plurality of two-fluid nozzles 8 increases as the distance of each two-fluid nozzle 8 from the center Cr of the polishing pad 2 increases. By controlling the gas pressure in this way, the two-fluid nozzles 8 can uniformly clean the entire polishing surface 2a of the polishing pad 2.

[0162] Refer to Figure 21 The configurations of the plurality of liquid flow control valves 71, the plurality of gas flow control valves 73, and the plurality of pressure regulators 75 described Figures 1 to 20 can be applied to each of the embodiments described

[0163] Figure 22It is a schematic diagram showing another embodiment of the non-contact pad cleaning device. Figure 23 It is Figure 22 A top view of the two-fluid liquid nozzle 8 and the pad cleaning nozzle 9 shown. The structure of this embodiment not specifically described is the same as the embodiment described with reference to Figure 1 Therefore, the repeated description thereof is omitted. The non-contact pad cleaning device includes a nozzle swing mechanism 90 that swings a plurality of two-fluid nozzles 8 along the polishing surface 2a. The plurality of two-fluid nozzles 8 are held by a nozzle holding portion 35. The plurality of two-fluid nozzles 8 are connected to a liquid supply line 61 and a gas supply line 65. The pad cleaning nozzle 9 is arranged downstream of the two-fluid nozzle 8 in the rotational direction of the polishing pad 2.

[0164] The nozzle swing mechanism 90 is configured to swing the plurality of two-fluid nozzles 8 in the radial direction of the polishing pad 2 by swinging the nozzle holding portion 35. The nozzle swing mechanism 90 is configured to be able to change the swing speed of the plurality of two-fluid nozzles 8. In one embodiment, the nozzle swing mechanism 90 is configured to swing the plurality of two-fluid nozzles 8 in the radial direction of the polishing pad 2 by rotating the nozzle holding portion 35 around its end in a clockwise and counterclockwise direction alternately by a predetermined angle. In another embodiment, the nozzle swing mechanism 90 can be configured to swing the plurality of two-fluid nozzles 8 in the radial direction of the polishing pad 2 by translating the nozzle holding portion 35.

[0165] Figure 24 It is a view of the two-fluid nozzle 8 observed from the direction indicated by arrow A in Figure 22 . The ejection port 8a of each two-fluid nozzle 8 faces outward in the radial direction of the polishing pad 2. The inclination angle θ of each two-fluid nozzle 8 with respect to the direction perpendicular to the polishing surface 2a is greater than 0 degree and less than or equal to 60 degrees. More preferably, the inclination angle θ of each two-fluid nozzle 8 is in the range of 15 to 30 degrees. The plurality of two-fluid nozzles 8 can be inclined at different angles with respect to the polishing surface 2a.

[0166] Since the ejection ports 8a of the plurality of two-fluid nozzles 8 face outward in the radial direction of the polishing pad 2, the two-fluid jets ejected from the plurality of ejection ports 8a form a liquid flow that faces outward on the polishing surface 2a. The outward flow of this liquid is accelerated by the centrifugal force generated by the rotating polishing pad 2, and foreign matters such as abrasive debris can be washed off from the polishing pad 2.

[0167] The arrangement of the two-fluid nozzles 8 is not limited to the embodiment described with reference to Figures 22 to 24 . In one embodiment, a plurality of two-fluid nozzles 8 can be arranged in a straight line. In the embodiment described with reference to Figures 22 to 24 , five two-fluid nozzles 8 are provided, but the number of two-fluid nozzles 8 is not limited to the above embodiment. In one embodiment, a single two-fluid nozzle 8 can be provided.

[0168] Reference Figures 1 to 24 The described embodiments may be appropriately combined. Reference Figures 1 to 21 The structures of the described embodiments, for example, the fine bubble generator 78, the ultrasonic generator 87, the liquid heating device 83, the inclination of the two-fluid nozzle 8 with respect to the polishing surface 2a, etc., may also be applicable to the reference Figures 22 to 24 described embodiments.

[0169] The above-described embodiments are described for the purpose that a person having ordinary knowledge in the technical field to which the present invention pertains can implement the present invention. Various modifications of the above-described embodiments can of course be made by those skilled in the art, and the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but the technical idea defined by the scope of protection claimed by the present invention is interpreted in the broadest scope.

Claims

1. A non-contact pad cleaning device for cleaning the grinding surface of a grinding pad used for grinding a workpiece in a non-contact manner, characterized in that: have: A rotating table, the rotating table is used to rotate the grinding pad; A plurality of dual-fluid nozzles, the plurality of dual-fluid nozzles being disposed above the polishing pad; as well as a liquid supply line and a gas supply line, wherein the liquid supply line and the gas supply line are connected to the plurality of two-fluid nozzles, The plurality of two-fluid nozzles are arranged along the radial direction of the polishing pad. The ejection outlets of the plurality of two-fluid nozzles when viewed from a direction perpendicular to the polishing surface of the polishing pad are inclined with respect to a reference line extending in a radial direction of the polishing pad.

2. The non-contact pad cleaning device according to claim 1, characterized in that: The ejection outlets of the plurality of two-fluid nozzles are inclined in the same direction as the rotation direction of the polishing pad when viewed from a direction perpendicular to the polishing surface of the polishing pad.

3. The non-contact pad cleaning device according to claim 1, characterized in that: The ejection outlets of the plurality of two-fluid nozzles when viewed from a direction perpendicular to the polishing surface of the polishing pad are located on the reference line.

4. The non-contact pad cleaning device according to claim 1, characterized in that: The inclination angle of the ejection outlets of the plurality of two-fluid nozzles relative to the reference line when viewed from a direction perpendicular to the polishing surface of the polishing pad increases as the distance between each two-fluid nozzle and the center of the polishing pad increases.

5. The non-contact pad cleaning device according to claim 4, characterized in that: The distance between the ejection outlets of the plurality of two-fluid nozzles and the reference line when viewed from a direction perpendicular to the polishing surface of the polishing pad increases as the distance between each two-fluid nozzle and the center of the polishing pad increases. The distance between the ejection outlet of each two-fluid nozzle and the reference line is a distance from the reference line toward the downstream side in the rotation direction of the polishing pad.

6. The non-contact pad cleaning device according to claim 1, characterized in that: A fine bubble generator connected to the liquid supply line is also provided.

7. The non-contact pad cleaning device according to claim 1, characterized in that: A liquid heating device is further provided, the liquid heating device being connected to the liquid supply line and heating the liquid flowing in the liquid supply line.

8. The non-contact pad cleaning device according to claim 1, characterized in that: A pad cleaning nozzle is further provided to form a jet flow of a liquid discharge fluid, and the pad cleaning nozzle is used to guide the liquid contained in the two fluids on the polishing surface of the polishing pad to the outer periphery of the polishing pad.

9. The non-contact pad cleaning device according to claim 8, characterized in that: Also available: a liquid discharge fluid circuit that supplies liquid discharge fluid to the pad washing nozzle; and a fine bubble generator that is coupled to the liquid discharge fluid circuit.

10. The non-contact pad cleaning device according to claim 8, characterized in that The pad cleaning nozzle is arranged downstream of the plurality of two-fluid nozzles in the rotation direction of the polishing pad.

11. The non-contact pad cleaning device according to claim 1, characterized in that: The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The distance between the ejection port of the outer circumferential-side two-fluid nozzle and the polishing surface is smaller than the distance between the ejection port of the central-side two-fluid nozzle and the polishing surface.

12. The non-contact pad cleaning device according to claim 1, characterized in that: The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The distance between the jet outlet of the outer circumferential-side two-fluid nozzle and the polishing surface is greater than the distance between the jet outlet of the central-side two-fluid nozzle and the polishing surface.

13. The non-contact pad cleaning device according to claim 1, characterized in that: The liquid supply line has a plurality of branch liquid lines respectively connected to the plurality of two-fluid nozzles. The non-contact pad cleaning device further comprises: a plurality of liquid flow control valves respectively connected to the plurality of branch liquid lines; and an operation control unit that independently controls the operation of the plurality of liquid flow control valves. The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The operation control unit controls the operation of the plurality of liquid flow control valves so that the flow rate of the liquid supplied to the outer circumferential-side two-fluid nozzle is greater than the flow rate of the liquid supplied to the center-side two-fluid nozzle.

14. The non-contact pad cleaning device according to claim 1, characterized in that The liquid supply line has a plurality of branch liquid lines respectively connected to the plurality of two-fluid nozzles. The non-contact pad cleaning device further comprises: a plurality of liquid flow control valves respectively connected to the plurality of branch liquid lines; and an operation control unit that independently controls the operation of the plurality of liquid flow control valves. The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The operation control unit controls the operation of the plurality of liquid flow control valves so that the flow rate of the liquid supplied to the center-side two-fluid nozzle is greater than the flow rate of the liquid supplied to the outer-circumference-side two-fluid nozzle.

15. The non-contact pad cleaning device according to claim 1, characterized in that The gas supply line has a plurality of branch gas lines respectively connected to the plurality of two-fluid nozzles. The non-contact pad cleaning device further comprises: a plurality of gas flow control valves respectively connected to the plurality of branch gas lines; and an operation control unit for independently controlling the operation of the plurality of gas flow control valves. The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The operation control unit controls the operation of the plurality of gas flow control valves so that the flow rate of the gas supplied to the outer circumferential side two-fluid nozzle is greater than the flow rate of the gas supplied to the center side two-fluid nozzle.

16. The non-contact pad cleaning device according to claim 1, characterized in that The gas supply line has a plurality of branch gas lines respectively connected to the plurality of two-fluid nozzles. The non-contact pad cleaning device further comprises: a plurality of gas flow control valves respectively connected to the plurality of branch gas lines; and an operation control unit for independently controlling the operation of the plurality of gas flow control valves. The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The operation control unit controls the operation of the plurality of gas flow control valves so that the flow rate of the gas supplied to the center-side two-fluid nozzle is greater than the flow rate of the gas supplied to the outer-side two-fluid nozzle.

17. The non-contact pad cleaning device according to claim 1, characterized in that The gas supply line has a plurality of branch gas lines respectively connected to the plurality of two-fluid nozzles. The non-contact pad cleaning device further comprises: a plurality of pressure regulators respectively connected to the plurality of branch gas lines; and an operation control unit that independently controls the operation of the plurality of pressure regulators. The plurality of two-fluid nozzles include a central two-fluid nozzle located at a central side of the polishing pad and a peripheral two-fluid nozzle located at an outer peripheral side of the polishing pad. The operation control unit controls the operations of the plurality of pressure regulators so that the pressure of the gas supplied to the outer circumferential side two-fluid nozzle is higher than the pressure of the gas supplied to the center side two-fluid nozzle.

18. A non-contact pad cleaning device for cleaning the grinding surface of a grinding pad used for grinding a workpiece in a non-contact manner, characterized in that: have: A rotating table, the rotating table is used to rotate the grinding pad; A dual-fluid nozzle, the dual-fluid nozzle is arranged above the polishing pad; a liquid supply line and a gas supply line connected to the two-fluid nozzle; and A nozzle swing mechanism, wherein the nozzle swing mechanism causes the two-fluid nozzle to swing along the grinding surface, The ejection port of the two-fluid nozzle faces outward in the radial direction of the polishing pad.

19. The non-contact pad cleaning device according to claim 18, characterized in that A fine bubble generator connected to the liquid supply line is also provided.

20. The non-contact pad cleaning device of claim 18, wherein: A liquid heating device is further provided, the liquid heating device being connected to the liquid supply line and heating the liquid flowing in the liquid supply line.

21. The non-contact pad cleaning device of claim 18, wherein: A pad cleaning nozzle is further provided to form a jet flow of a liquid discharge fluid, and the pad cleaning nozzle is used to guide the liquid contained in the two fluids on the polishing surface of the polishing pad to the outer periphery of the polishing pad.

22. The non-contact pad cleaning device of claim 21, wherein: Also available: a liquid exhaust fluid circuit that supplies liquid exhaust fluid to the pad washing nozzles; and A fine bubble generator is connected to the liquid discharge fluid line.

23. The non-contact pad cleaning device of claim 21, wherein: The pad cleaning nozzle is arranged downstream of the two-fluid nozzle in the rotation direction of the polishing pad.

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