Circuit board cleaning apparatus and circuit board polishing apparatus

Abstract

This prevents the cleaning solution from being forcefully ejected during the self-cleaning of the circuit board cleaning nozzle after polishing. [Solution] The substrate cleaning apparatus comprises a first cleaning unit 51 equipped with a first cleaning nozzle, a second cleaning unit 52 equipped with a second nozzle having a smaller diameter nozzle opening than the first cleaning nozzle, a first valve 81 that switches between a first open state in which cleaning liquid is sprayed from the first cleaning nozzle and a first closed state in which cleaning liquid is not sprayed, a second valve 82 that switches between a second open state in which cleaning liquid is sprayed from the second cleaning nozzle and a second closed state in which cleaning liquid is not sprayed, and a control unit that controls the first valve and the second valve. The control unit performs a first self-cleaning in which cleaning liquid is discharged from the first valve and a second self-cleaning in which cleaning liquid is discharged from the second valve when the substrate is not in the cleaning position, and controls the first self-cleaning to be performed before the second self-cleaning.

Description

Technical Field

[0001] The present invention relates to an apparatus for cleaning a substrate such as a semiconductor wafer and a substrate polishing apparatus provided with the cleaning apparatus.

Background Art

[0002] A polishing apparatus for polishing the surface of a substrate such as a semiconductor wafer includes a polishing module, a cleaning module, and a substrate transfer mechanism. The polishing module includes a polishing table having a polishing pad and a polishing head (top ring) for holding the substrate. The polishing head transfers the substrate between a delivery position for delivering the substrate and a polishing position overlapping the polishing pad. At the polishing position, the substrate surface is pressed against the polishing pad with a predetermined pressure, and while supplying a polishing liquid (slurry), the polishing pad and the substrate are relatively moved to bring the substrate into sliding contact with the polishing pad to polish the substrate surface to a predetermined film thickness.

[0003] The cleaning module includes a plurality of cleaning modules for performing rough cleaning (primary cleaning) and finish cleaning (secondary cleaning) of the substrate surface, and removing polishing residues (particles) such as polishing liquid and polishing dust remaining on the substrate after the polishing process. The cleaning module is provided with a plurality of cleaning lines for cleaning a plurality of substrates (see Patent Document 1).

[0004] If particles remain on the substrate surface after the polishing process, it affects the yield of semiconductor devices. Therefore, it is desirable to remove the particles before delivering them to the cleaning module. Thus, a polishing apparatus is also disclosed in which, at a cleaning position provided on the side of the polishing table in the polishing module, while rotating the substrate held by the top ring, a cleaning liquid is jetted from a plurality of cleaning nozzles provided below the substrate to perform a cleaning process on the substrate after the polishing process (see Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] When cleaning a circuit board by spraying cleaning fluid from multiple cleaning nozzles located below the board, the nozzles are angled upwards. As a result, cleaning fluid or polishing fluid that drips from the board during cleaning may enter the inside of the nozzles through the nozzle openings. Therefore, the nozzle openings are cleaned (self-cleaning) by spraying cleaning fluid from the cleaning nozzles when there is no circuit board above them (during polishing or transport).

[0007] The cleaning nozzle system consists of a first cleaning nozzle with a large nozzle area and a second cleaning nozzle with a smaller nozzle area compared to the first nozzle. These multiple nozzles are connected to a common pump via corresponding valves, and the spraying of cleaning fluid from the nozzles stops when the valves are closed after the substrate cleaning is complete.

[0008] In this process, a certain water pressure is generated in the path of the cleaning fluid from the pump to the valve. If all valves are opened to start self-cleaning under these conditions, the cleaning fluid may be forcefully ejected from the second cleaning nozzle, which has a small nozzle area, potentially causing the cleaning fluid to adhere to the housing and other cleaning nozzles near the cleaning position. In particular, immediately after circuit board cleaning, polishing fluid adheres to the cleaning nozzles. If the cleaning fluid containing polishing fluid is forcefully ejected during self-cleaning, the area around the cleaning nozzles may become contaminated, potentially hindering the cleaning effect immediately after circuit board polishing.

[0009] The present invention has been made in view of the above, and aims to provide a substrate cleaning apparatus and a substrate polishing apparatus that can perform self-cleaning efficiently by suppressing the forceful ejection of cleaning liquid containing polishing liquid during self-cleaning. [Means for solving the problem]

[0010] One aspect of the present invention is a substrate cleaning apparatus for cleaning a substrate at a cleaning position after the substrate has been polished, comprising: a first cleaning unit equipped with a first cleaning nozzle for spraying cleaning liquid toward the substrate at the cleaning position; a second cleaning unit equipped with a second cleaning nozzle for spraying cleaning liquid toward the substrate at the cleaning position, the second nozzle having a smaller diameter of its nozzle opening than the diameter of the nozzle opening of the first cleaning nozzle; a first valve for switching between a first open state in which cleaning liquid is sprayed from the first cleaning nozzle and a first closed state in which cleaning liquid is not sprayed from the first cleaning nozzle; a second valve for switching between a second open state in which cleaning liquid is sprayed from the second cleaning nozzle and a second closed state in which cleaning liquid is not sprayed from the second cleaning nozzle; and a control unit for controlling the first valve and the second valve to spray cleaning liquid from the first cleaning unit and the second cleaning unit, respectively. The control unit controls the operation of the first valve so that when the substrate is not in the cleaning position, the first cleaning nozzle switches from the first closed state to the first open position, thereby performing a first self-cleaning procedure in which cleaning fluid is discharged from the first valve. The control unit also controls the operation of the second valve so that when the substrate is not in the cleaning position, the second cleaning nozzle switches from the second closed state to the second open position, thereby performing a second self-cleaning procedure in which cleaning fluid is discharged from the second valve. The control unit controls the first self-cleaning procedure to be performed before the second self-cleaning procedure.

[0011] One aspect of the present invention is a substrate polishing apparatus comprising a polishing table and a top ring, and the above-mentioned substrate cleaning apparatus. [Effects of the Invention]

[0012] According to the present invention, self-cleaning can be performed efficiently by suppressing the forceful ejection of the cleaning solution containing the polishing fluid during self-cleaning. [Brief explanation of the drawing]

[0013] [Figure 1] It is a plan view showing a schematic configuration of a substrate polishing apparatus provided with a substrate cleaning apparatus according to an embodiment of the present invention. [Figure 2] It is a plan view showing the configuration of a polishing unit. [Figure 3] It is a perspective view of the polishing unit in FIG. 2. [Figure 4] It is a schematic cross-sectional view showing the internal configuration of a top ring. [Figure 5] It is a plan view for explaining how a substrate moves among a delivery position, a cleaning position, and a polishing position. [Figure 6] It is a plan view showing the configuration of an auxiliary cleaning unit. [Figure 7] It is a plan view showing the configuration of an auxiliary cleaning unit and showing a state in which cleaning liquid is sprayed from nozzles constituting a first cleaning unit and a second cleaning unit. [Figure 8] It is an explanatory view showing an outline of a mechanism for supplying cleaning liquid to a first cleaning unit and a second cleaning unit. [Figure 9] It is a functional block diagram showing the configuration of a substrate polishing apparatus. [Figure 10] It is a flowchart showing a procedure for substrate polishing and cleaning. [Figure 11] It is a flowchart showing a procedure for self-cleaning. [Figure 12] It is a flowchart showing an example of operations of a first cleaning unit and a second cleaning unit in self-cleaning.

MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the configuration of a substrate polishing apparatus provided with a substrate cleaning apparatus according to the present embodiment. The substrate polishing apparatus 10 includes a rectangular housing 11 and is partitioned by partition walls into a load / unload unit 12, a polishing unit 13, and a cleaning unit 14. Further, the substrate polishing apparatus 10 includes a control unit 15 that controls the operations of each unit.

[0015] The load / unload unit 12 includes a plurality of front load units where a substrate cassette 20 for accommodating substrates W such as a number of semiconductor wafers is set. A traveling mechanism 21 is laid along the arrangement of the substrate cassettes 20 in the load / unload unit 12, and a transfer robot 22 movable along the arrangement direction of the substrate cassettes 20 is installed on this traveling mechanism 21. The transfer robot 22 receives the substrate W before polishing from the substrate cassette 20 and transfers it toward the polishing unit 13, and receives the substrate W after polishing / cleaning treatment from the cleaning unit 14.

[0016] The polishing unit 13 includes a plurality of polishing units 13A to 13D for polishing (flattening) the substrate W. These first polishing unit 13A to fourth polishing unit 13D are arranged along the longitudinal direction of the substrate polishing apparatus 10. Details of the configuration of the polishing unit will be described later.

[0017] Adjacent to the first polishing unit 13A and the second polishing unit 13B, a first linear transporter 16 is arranged. This first linear transporter 16 transfers the substrate W among four transfer positions (the first transfer position A1 to the fourth transfer position A4 in order from the load / unload unit 一侧) along the direction in which the polishing units 13A and 13B are arranged.

[0018] Adjacent to the third polishing unit 13C and the fourth polishing unit 13D, a second linear transporter 17 is arranged. This second linear transporter 17 transfers the substrate W among three transfer positions (the fifth transfer position A5 to the seventh transfer position A7 in order from the load / unload unit 一侧) along the direction in which the polishing units 13C and 13D are arranged.

[0019] The cleaning unit 14 houses a first cleaning unit 23 and a second cleaning unit 24 for cleaning the substrate W after polishing, and a drying unit 25 for drying the substrate W after cleaning. A first transport unit 26 is positioned between the first cleaning unit 23 and the second cleaning unit 24 to transfer the substrate W between them. A second transport unit 27 is positioned between the second cleaning unit 24 and the drying unit 25 to transfer the substrate W between them.

[0020] Within the first cleaning unit 23, multiple (e.g., two) primary cleaning modules are arranged vertically. Similarly, within the second cleaning unit 24, multiple (e.g., two) secondary cleaning modules are arranged vertically. The primary and secondary cleaning modules are cleaning machines that clean substrates using a cleaning solution, and for example, a roll sponge type cleaning machine can be used.

[0021] The drying unit 25 contains multiple (for example, two) drying modules arranged vertically, and dries the substrate W by spraying gas from nozzles (not shown) onto the rotating substrate W. Alternatively, the substrate W may be rotated at high speed and dried by centrifugal force. The transport robot 22 removes the washed and dried substrate W from the drying unit 25 and returns it to the substrate cassette 20.

[0022] Figures 2 and 3 show the schematic configuration of the first polishing unit 13A according to this embodiment. The second polishing units 13B to the fourth polishing units 13D have the same configuration as the first polishing unit 13A, so the first polishing unit 13A will be described below.

[0023] The first polishing unit 13A includes a polishing table 30 to which a polishing pad 31 having a polishing surface is attached, a top ring 32 for holding the substrate W and polishing it while pressing it against the polishing pad 31 on the polishing table 30 with a predetermined pressure, a polishing fluid supply nozzle 33 for supplying polishing fluid and dressing fluid (e.g., pure water) to the polishing pad 31, a dresser 34 for dressing the polishing surface of the polishing pad 31, and an atomizer 35 for spraying a mixed fluid of liquid (e.g., pure water) and gas (e.g., nitrogen gas) or liquid (e.g., pure water) in a mist onto the polishing surface. The top ring 32 is rotatable by a swing arm 37 connected via a top ring shaft 36.

[0024] The polishing pad 31 attached to the polishing table 30 constitutes the polishing surface for polishing the substrate W. Alternatively, fixed abrasive grains can be used instead of the polishing pad 31. The top ring 32 and the polishing table 30 are configured to rotate around their respective axes (see arrow in Figure 3). The substrate W is held by vacuum suction on the lower surface of the top ring 32. Polishing fluid is supplied from the polishing fluid supply nozzle 33 to the upper surface (polishing surface) of the polishing pad 31, and the substrate W is pressed against the polishing pad 31 by the top ring 32 for polishing.

[0025] In Figure 4, the top ring 32 is connected to the lower end of the top ring shaft 36 via a universal joint (not shown), which is a ball joint. The top ring 32 comprises a roughly disc-shaped top ring body 38, a retainer ring 39 positioned below the top ring body 38, and a circular membrane (elastic pad) 40 that contacts the substrate W. The top ring body 38 is made of a material with high strength and rigidity, such as metal or ceramics. The retainer ring 39 is made of a highly rigid resin material or ceramics.

[0026] The membrane 40 is attached to the lower surface of the top ring body 38. Between the membrane 40 and the top ring body 38, multiple pressure chambers (airbags) P1, P2, P3, and P4 are formed by multiple partition walls 40a to 40d formed in the membrane 40. Pressurized fluid such as pressurized air is supplied to the pressure chambers P1, P2, P3, and P4 via fluid passages G1, G2, G3, and G4, respectively, or a vacuum is applied. The central pressure chamber P1 is circular, while the other pressure chambers P2, P3, and P4 are annular, and these pressure chambers P1, P2, P3, and P4 are arranged concentrically.

[0027] The internal pressures of pressure chambers P1, P2, P3, and P4 can be changed independently of each other by a pressure adjustment unit (not shown), thereby allowing independent adjustment of the pressing force on the four regions of the substrate W, namely the central part, the inner intermediate part, the outer intermediate part, and the peripheral part.

[0028] To prevent the substrate W from flying out of the top ring 32 during polishing, a retainer ring 39 provided on the lower surface of the top ring 32 holds the substrate W in place, surrounding its outer periphery. An opening is formed in the part of the membrane 40 that constitutes the pressure chamber P3, and by creating a vacuum in the pressure chamber P3, the substrate W is held in place by adsorption to the top ring 32. Furthermore, by supplying nitrogen gas, dry air, compressed air, etc., to this pressure chamber P3, the substrate W is released from the top ring 32.

[0029] An elastic bag forming a pressure chamber P5 is positioned between the retainer ring 39 and the top ring body 38. The retainer ring 39 is vertically movable relative to the top ring body 38. A fluid passage G5 is connected to the pressure chamber P5, and a pressurized fluid such as pressurized air is supplied to the pressure chamber P5 through the fluid passage G5. The internal pressure of the pressure chamber P5 is adjustable by a pressure adjustment unit, and the pressing force of the retainer ring 39 against the polishing pad 31 can be adjusted independently of the pressing force against the substrate W.

[0030] The substrate W may be polished using any of the first polishing unit 13A, the second polishing unit 13B, the third polishing unit 13C, and the fourth polishing unit 13D, or it may be polished continuously using a plurality of polishing units pre-selected from these polishing units 13A to 13D. By equalizing the polishing time of all polishing units 13A to 13D, throughput can be improved.

[0031] In Figure 1, the substrate W is transported to polishing units 13A and 13B by the first linear transporter 16. The top ring 32 of the first polishing unit 13A moves between a polishing position above the polishing table 30 (no reference numerals in Figure 5, polishing pad 31) and a second transport position A2 to the side of the polishing table 30. The transfer of the substrate to the top ring 32 takes place at the second transport position A2, which becomes the transfer position TP2 (see Figure 5).

[0032] Similarly, the top ring of the second polishing unit 13B (third polishing unit 13C, fourth polishing unit 13D) moves between a polishing position above the polishing table (polishing pad) and a third transport position A3 (sixth transport position A6 for the third polishing unit 13C; seventh transport position A7 for the fourth polishing unit 13D) on the side of the polishing table, and the transfer of the substrate to the top ring is performed at the third transport position A3 (sixth transport position A6, seventh transport position A7) as the substrate transfer position.

[0033] A lifter 43 is positioned at the first transport position A1 to receive substrates from the transport robot 22. The substrates are transferred from the transport robot 22 to the first linear transporter 16 via this lifter 43. A swing transporter 44 with a reversing function is positioned between the first linear transporter 16, the second linear transporter 17, and the cleaning unit 14, and is used to transfer substrates from the first linear transporter 16 to the second linear transporter 17 and to transport substrates from the polishing unit 13 to the cleaning unit 14.

[0034] Figure 5 shows a schematic representation of the positional relationship between the polishing table 30 (reference numeral omitted in Figure 5, polishing pad 31), top ring 32, and auxiliary cleaning unit 50 of the first polishing unit 13A. The top ring 32 is rotatable by a swing arm 37 connected via a top ring shaft 36, and is configured to move between a polishing position TP1 above the polishing table 31, a transfer position TP2 (second transport position A2) to the side of the polishing table 30A, and a cleaning position TP3 between the polishing position TP1 and the transfer position TP2. The auxiliary cleaning unit 50 is positioned at the location of the top ring 32 corresponding to the cleaning position TP3.

[0035] The configuration of the top ring 32 and the auxiliary cleaning unit 50 described above is the same for the second polishing unit 13B to the fourth polishing unit 13D, and a detailed explanation is omitted. The auxiliary cleaning unit 50 may be provided in all of the first polishing unit 13A to the fourth polishing unit 13D, or the auxiliary cleaning unit 50 may be omitted in one or more polishing units.

[0036] Figures 6 and 7 are plan views showing the configuration of the auxiliary cleaning unit 50. The auxiliary cleaning unit 50 comprises a first cleaning unit 51, a second cleaning unit 52, a retainer ring (RR) side cleaning nozzle 53, and an RR / membrane cleaning nozzle 54. The first cleaning unit 51 is equipped with a plurality (five in this embodiment) of substrate cleaning nozzles 61 to 65. The second cleaning unit is equipped with a plurality (four in this embodiment) of assist nozzles 71 to 74. The auxiliary cleaning unit 50 performs cleaning on the polished substrate W at the cleaning position TP3 and the top ring 32 that holds it. By performing cleaning before the polished substrate W is transported to the cleaning unit 14, particles remaining on the surface of the substrate W can be effectively removed.

[0037] The substrate cleaning nozzles 61-65 constituting the first cleaning unit 51 are, for example, two-fluid nozzles that mix liquid and gas and spray the mixed fluid (cleaning solution) onto the surface of the substrate. This cleaning machine can remove minute particles on the substrate with minute droplets and impact energy. The substrate cleaning nozzles 61-65 are arranged in a straight line along the radial direction below the top ring 32 when the top ring 32 is in the cleaning position TP3. The substrate cleaning nozzles 61-65 spray the cleaning solution vertically upward from below the substrate W onto the surface of the substrate W, which rotates with the top ring 32 in the direction of the arrow in Figure 7 when the substrate is in the cleaning position TP3.

[0038] The substrate cleaning nozzles 61-65 can be selected from those that use a pressurized injection of a mixed fluid (two fluids) of liquid (such as pure water) and gas, a high-speed jet injection, or those that apply ultrasonic waves. Examples of liquids that can be supplied to the substrate cleaning nozzles 61-65 include pure water, acidic or alkaline chemical solutions or surfactants, liquids containing trace amounts of carbon dioxide to suppress static electricity, N2 gas saturated water, and fine bubble-containing water.

[0039] As shown in Figure 7, the first cleaning unit 51 has a first substrate cleaning nozzle 61 located at one end (rear side) near the center of the top ring 32, and a fifth substrate cleaning nozzle 65 located at the other end (front side) near the outer circumference of the top ring 32, with these nozzles positioned accordingly. The cleaning fluid sprayed from each of the substrate cleaning nozzles 61 to 65 is an elongated, roughly elliptical shape 61a to 65a, with its major axis slightly inclined from the radial direction of the top ring 32 so that they do not overlap. As a result, when the top ring 32 rotates, a flow of cleaning fluid is formed along the direction of rotation of the top ring 32 toward the outer circumference of the top ring 32 (substrate W), making it easier for the cleaning fluid to diffuse over the entire surface of the substrate W. The flow along the direction of rotation of the top ring 32 becomes a fast flow due to the centrifugal force caused by the rotation of the top ring 32, making it easier for cleaning fluid containing particles such as abrasives to be discharged to the outside from the outer edge of the substrate W.

[0040] The retainer ring (RR) side cleaning nozzle 53 is positioned below the top ring 32 at cleaning position TP3. With the top ring 32 rotating at cleaning position TP3, the nozzle sprays cleaning fluid 53a diagonally upward toward the sides and bottom of the retainer ring 39. This makes it possible to remove particles that have adhered to the sides of the retainer ring 39 after polishing.

[0041] Furthermore, the RR / membrane cleaning nozzle 54 is positioned below the top ring 32 at cleaning position TP3. With the top ring 32 rotating at cleaning position TP3, the cleaning solution 54a is sprayed vertically upward toward the boundary between the retainer ring 39 and the membrane 40. This makes it possible to remove particles that have adhered to the gap between the retainer ring 39 and the membrane 40 after polishing.

[0042] Here, the spraying of cleaning fluid from the retainer ring (RR) side cleaning nozzle 53 and the RR / membrane cleaning nozzle 54 may cause particles adhering to the retainer ring 39 and membrane 40 to be scattered toward the substrate W held by the top ring 32. For this reason, the timing of stopping the spraying of cleaning fluid from the retainer ring (RR) side cleaning nozzle 53 and the RR / membrane cleaning nozzle 54 is controlled to be simultaneous with or earlier than the timing of stopping the spraying of cleaning fluid from the substrate cleaning nozzles 61-65. Even if particles adhering to the retainer ring 39 and membrane 40 are scattered toward the substrate W, they can be removed by the spraying of cleaning fluid from the substrate cleaning nozzles 61-65.

[0043] In Figures 6 and 7, the assist nozzles 71 to 74, which constitute the second spray unit assisting in substrate cleaning, are single-fluid nozzles that spray cleaning fluid onto the surface of the substrate. When the top ring 32 is in the cleaning position TP3, they are arranged in a straight line below the top ring 32. The assist nozzles 71 to 74 can be selected from spray nozzles (e.g., single-fluid nozzles that spread in a fan shape), high-speed jet nozzles, or nozzles to which ultrasonic waves are applied. Examples of liquids that can be supplied to the assist nozzles 71 to 74 include pure water, acidic or alkaline chemicals or surfactants, liquids containing a small amount of carbon dioxide to suppress static electricity, N2 gas saturated water, and fine bubble-containing water.

[0044] The assist nozzles 71-74 spray a roughly elliptical cleaning liquid (e.g., pure water) 71a-74a (see Figure 7) vertically upward onto the surface of the substrate W, which rotates with the top ring 32 in the direction of the arrow in Figure 7 at the cleaning position TP3. The assist nozzles 71-74 are arranged so that the sprayed cleaning liquids 71a-74a overlap each other, and the cleaning liquids 71a-74a ejected from all of these assist nozzles 71-74 combine to form a single line of cleaning liquid.

[0045] The cleaning liquid sprayed onto the substrate W from the assist nozzles 71-74 moves toward the outer circumference of the substrate W due to centrifugal force as the top ring 32 rotates. In this embodiment, the spray position of the cleaning liquid onto the substrate W by the assist nozzles 71-74 is downstream of the spray position of the cleaning liquid from the substrate cleaning nozzles 61-65 with respect to the rotation direction of the top ring 32 (see Figure 7). As a result, the cleaning liquid sprayed onto the substrate W from the substrate cleaning nozzles 61-65 moves toward the outer circumference of the substrate W together with the cleaning liquid from the assist nozzles 71-74, improving particle discharge.

[0046] Furthermore, the cleaning fluid ejected from the assist nozzles 71-74 forms a line that includes the area near the center of the top ring 32. As a result, the rotation of the top ring 32 allows the liquid to adhere to a wide area, including the center of the substrate W supported by the top ring 32, effectively preventing the substrate W from drying out.

[0047] During the cleaning process of the substrate W, it is preferable that the spraying of cleaning fluid from the assist nozzles 71-74 stops after the spraying of cleaning fluid from the substrate cleaning nozzles 61-65, the retainer ring (RR) side cleaning nozzle 53, and the RR / membrane cleaning nozzle 54 stops. This allows the cleaning fluid adhering to the substrate W to be washed away by the substrate cleaning nozzles 61-65, the retainer ring (RR) side cleaning nozzle 53, and the RR / membrane cleaning nozzle 54.

[0048] Figure 8 is an explanatory diagram illustrating the general mechanism for supplying cleaning fluid to the first cleaning unit 51 and the second cleaning unit 52. The first cleaning unit 51 and the second cleaning unit 52 are connected to a common pipe 86 via a first valve 81 and a second valve 82, respectively, and this pipe 86 is connected to a flow controller 83. The flow controller 83 is connected to a cleaning fluid supply source (not shown) and supplies cleaning fluid to the first cleaning unit 51 and the second cleaning unit 52.

[0049] The first valve 81 and the second valve 82 are openable and closable electromagnetic valves, and are configured to be independently turned on and off by control signals from the nozzle control unit 94 of the control device 15, which will be described later. When the first valve 81 is opened (first open position), cleaning fluid is supplied from the flow controller 83 to the first cleaning unit 51, and the cleaning fluid is sprayed upward from the substrate cleaning nozzles 61 to 65 toward the back surface of the substrate W at the cleaning position TP3. When the first valve 81 is closed (first closed position), the supply of cleaning fluid from the flow controller 83 to the first cleaning unit 51 stops.

[0050] When the second valve 82 is opened (second open position), cleaning fluid is supplied from the flow controller 83 to the second cleaning unit 52, and the cleaning fluid is sprayed upward from the assist nozzles 71 to 74 toward the back surface of the substrate W at the cleaning position TP3. When the second valve 81 is closed (second closed position), the supply of cleaning fluid from the flow controller 83 to the second cleaning unit 52 stops.

[0051] Here, the substrate cleaning nozzles 61-65 constituting the first cleaning unit 51 have a larger nozzle diameter (area of ​​the opening from which the cleaning fluid is ejected) compared to the assist nozzles 71-74 constituting the second cleaning unit 52. This makes it possible to improve the cleaning effect of the first cleaning unit 51, which is a two-fluid nozzle, while suppressing the amount of cleaning fluid supplied.

[0052] When cleaning is performed by spraying cleaning fluid from multiple cleaning nozzles located below the substrate, the cleaning nozzles are directed upward, so cleaning fluid or polishing fluid that drips from the substrate during cleaning may enter the inside through the nozzle openings. For this reason, in the substrate polishing apparatus 10 of this embodiment, when the substrate W is in a position away from the cleaning position TP3 (i.e., when there is no substrate on the auxiliary cleaning unit 50), cleaning fluid is sprayed from the first cleaning unit 51 and the second cleaning unit 52 to clean the nozzle openings of the substrate cleaning nozzles 61 to 65 (first self-cleaning) and the nozzle openings of the assist nozzles 71 to 74 (second self-cleaning).

[0053] Here, when performing self-cleaning of the first cleaning unit 51 and the second cleaning unit 52, the first valve 81 corresponding to the first cleaning unit 51, which has a larger nozzle diameter, is opened first, and after a certain period of time, the second valve 82 corresponding to the second cleaning unit 52 is opened. In the cleaning process, if residual pressure (a certain amount of water pressure) is generated in the cleaning fluid path 86 from the flow controller to the valve due to the high flow rate discharge from the first cleaning unit 51 and the second cleaning unit 52, the cleaning fluid is ejected first from the substrate cleaning nozzles 61-65, which have larger nozzle diameters. In other words, the first self-cleaning is performed before the second self-cleaning. As a result, when the second valve 81 moves to the second open position, the pressure of the cleaning fluid ejected from the assist nozzles 71-74 can be reduced, preventing the cleaning fluid from splashing up, and consequently reducing the risk of the cleaning fluid adhering to the housing or other cleaning nozzles near the cleaning position.

[0054] In Figure 8, a first external cleaning nozzle 84 and a second external cleaning nozzle 85 are provided diagonally to the sides of the first cleaning unit 51 and the second cleaning unit 52. During and / or immediately after self-cleaning, the first external cleaning nozzle 84 sprays liquid (e.g., pure water) diagonally downwards toward the substrate cleaning nozzles 61-65, and the second external cleaning nozzle 85 sprays liquid (e.g., pure water) diagonally downwards toward the assist nozzles 71-74. This washes away any cleaning and polishing liquid remaining on the surfaces of the substrate cleaning nozzles 61-65 and assist nozzles 71-74 due to self-cleaning.

[0055] Inside the housing 11 is a control unit 15 that controls the operation of each part of the substrate polishing apparatus 10. The control unit 15 is, for example, a general-purpose computer device and includes a CPU, a memory 70 for storing control programs, a display unit, and the like. The control unit 15 also has an input unit that accepts external inputs. Here, external inputs may include mechanical operations by the user, as well as signals from external devices via wired or wireless connections.

[0056] The control unit 15 controls the movement of each component of the circuit board polishing apparatus 10 by activating a control program stored in the memory unit 70. The control program for controlling the operation of the circuit board polishing apparatus 10 may be pre-installed on the computer that constitutes the control unit 15, or it may be stored on a storage medium such as a DVD, BD, or SSD, or it may be installed on the control unit 15 via the internet.

[0057] Figure 9 shows an example of the functional blocks of the control unit 15 of the substrate polishing apparatus 10. The control unit 15 includes a storage unit 90, a polishing control unit 91, an endpoint determination unit 92, a transport control unit 73, and a nozzle control unit 94. The polishing control unit 91 controls the rotation of the polishing table 30 and the top ring 32, as well as the pressure in the pressure chambers P1 to P5. The endpoint determination unit 92 uses an optical sensor (not shown) or the like to determine whether the amount of polishing of the substrate W has reached a set value, and terminates the substrate polishing if it has reached that value. The transport control unit 93 controls the transport of the substrate W within the substrate polishing apparatus 10, including the transport of the substrate W in the polishing units 13A to 13D.

[0058] The nozzle control unit 94 is connected to the atomizer 35, the substrate cleaning nozzles 71-75 that constitute the first cleaning unit 51, the assist nozzles 71-74 that constitute the second cleaning unit, the RR side cleaning nozzle 53, the RR / membrane cleaning nozzle 54, and the external cleaning nozzles 84, 85, and controls the spraying of cleaning fluid from each nozzle.

[0059] The following describes the substrate polishing and post-polishing cleaning processes in the substrate polishing apparatus 10 with the above configuration, using the flowchart in Figure 10. When the substrate W is transported to the polishing unit 13A, the top ring 32 holds the substrate W in a position surrounded by the retainer ring 39 by vacuum suction and transports it from the transfer position TP2 to the polishing position TP1 (step S10). The polishing unit 13A performs polishing on the substrate W by pressing the substrate W, which has reached the polishing position TP1, against the polishing pad 31 (step S11). During substrate polishing, the film thickness of the substrate W is measured and it is determined whether a predetermined film thickness has been reached (whether the polishing endpoint has been reached) (step S12). If the polishing endpoint has been reached, the substrate polishing is terminated (step S13).

[0060] Subsequently, the top ring 32 holding the substrate W is moved to the cleaning position TP3 (step S14). When the substrate W and top ring 32 reach the cleaning position TP3, the various nozzles constituting the auxiliary cleaning unit 50 (including the first nozzle 81 and the second nozzle 82) are driven while the top ring 32 is rotated to perform cleaning on the substrate W, top ring 32 and retainer ring 39 (step S15). This discharges particles adhering to the substrate W, top ring 32 and retainer ring 39 due to substrate polishing to the outside.

[0061] Here, the substrate cleaning nozzles 61-65, which are two-fluid nozzles, have the longitudinal direction of the sprayed cleaning liquid 61a-65a tilted in the direction of rotation of the substrate W. At this time, most of the cleaning liquid 61a-65a sprayed from the substrate cleaning nozzles flows downstream (radial outward direction), and a portion of the cleaning liquid 61a-65a flows upstream (radial center direction). Because the flow of the cleaning liquid 61a-65a downstream (radial outward direction) is fast, the cleaning liquid containing particles can be efficiently discharged to the outer periphery. Furthermore, with respect to the rotation direction of the substrate W, the assist nozzles 71-74 are positioned downstream of the substrate cleaning nozzles 61-65 and are tilted toward the substrate cleaning nozzles 61-65. The cleaning liquid sprayed from the assist nozzles 71-74 facilitates the flow of the cleaning liquid from the substrate cleaning nozzles 61-65 toward the outer periphery of the substrate W, allowing the cleaning liquid containing particles to be efficiently discharged to the outside of the substrate W.

[0062] In parallel with step S14 described above, the atomizer 35 is driven to spray cleaning fluid onto the polishing pad 30, and the dresser 34 is driven to start dressing the polishing pad 31 (step S16). As a result, the cleaning process of the substrate W held in the top ring 32 and the dressing process of the polishing pad 31 are performed in parallel. The dressing and cleaning processes of the polishing pad 31 are performed in parallel with the post-polishing cleaning process of the top ring 32 and the substrate W by the auxiliary cleaning unit 50. After a certain period of time has elapsed, the RR side cleaning nozzle 53 and the RR / membrane cleaning nozzle 54 are stopped, and the cleaning process for the retainer ring 39 and membrane 40 is completed (step S17). Subsequently, the substrate cleaning nozzles 61-65 and assist nozzles 71-74 are stopped (step S18). This completes the post-polishing cleaning process for the substrate W.

[0063] Subsequently, the spraying of cleaning solution by the atomizer 35 and the dressing of the polishing pad 30 are completed (step S19). This eliminates the risk of droplets containing particles remaining on the polishing pad 30 from the top ring 32 after the post-polishing cleaning process. Then, the top ring 32 is moved to the transfer position TP2 (step S20), and the polished substrate W is transported toward the cleaning section 14.

[0064] When the substrate W moves from the cleaning position TP3 to the transfer position TP2, self-cleaning is performed to clean the substrate cleaning nozzles 61-65 and assist nozzles 71-74 (step S21). Figure 11 is a flowchart showing the self-cleaning procedure, and Figure 12 is a timing chart showing an example of on / off control of the first valve 81 and the second valve 82 during self-cleaning.

[0065] In Figures 11 and 12, when self-cleaning is initiated, at time T1 (see Figure 12), the first valve 81 corresponding to the first cleaning unit 51 is opened (step S30). As a result, cleaning fluid is sprayed vertically upward from the substrate cleaning nozzles 61-65, removing the liquid (including slurry and polishing debris) that entered the substrate cleaning nozzles 61-65 from the substrate W during post-polishing cleaning.

[0066] At this point, because the first valve 81 was closed, a predetermined pressure was generated in the cleaning fluid piping leading to the first valve 81. When the first valve 81 opens first, the cleaning fluid is sprayed upward from the corresponding substrate cleaning nozzles 61-65. However, since the openings of the substrate cleaning nozzles 61-65 have a larger surface area than the assist nozzles 71-74 and the spray pressure is relatively low, it is possible to prevent the cleaning fluid from splashing upwards.

[0067] Subsequently, at time T2 (see Figure 12), the second valve 82 corresponding to the second cleaning unit 52 is opened (step S31). As a result, cleaning fluid is sprayed vertically upward from the assist nozzles 71-74, removing the liquid (including slurry and polishing debris) that entered the assist nozzles 71-74 from the substrate W during post-polishing cleaning. At this point, the first valve 81 is already open, and the pressure in the cleaning fluid piping leading to the second valve 81 has been reduced, thus suppressing the upward spraying of cleaning fluid from the corresponding assist nozzles 71-74.

[0068] Furthermore, the flow controller (flow rate control device) 83 controls the flow rate of the cleaning fluid supplied to the first cleaning unit 51 and the second cleaning unit 52 during the first self-cleaning and second self-cleaning processes so that it is less than the flow rate of the cleaning fluid when it is sprayed toward the substrate W at the cleaning position. This prevents excessive splashing of the cleaning fluid during self-cleaning.

[0069] Subsequently, the first external cleaning nozzle 84 and the second external cleaning nozzle 85 are opened, and cleaning fluid is sprayed onto the substrate cleaning nozzles 61-65 and assist nozzles 71-74 from an oblique upward direction (step S32). This removes the liquid (liquid containing slurry and polishing debris) adhering to the surfaces of the substrate cleaning nozzles 61-65 and assist nozzles 71-74.

[0070] After a certain period of time has elapsed since these nozzles began self-cleaning (indicated as "Y" in step S33), the external cleaning nozzles 81 and 82 are closed (step S34), and at time T3 (see Figure 12), the second valve 82 corresponding to the second cleaning unit 52 is closed (step S35). Then, at time T4 (see Figure 12), the first valve 81 corresponding to the first cleaning unit 51 is closed (step S36), and the self-cleaning process is completed.

[0071] In the above embodiment, self-cleaning is performed when the substrate W moves from the cleaning position TP3 to the handover position TP2. However, the embodiment is not limited to the above example, and self-cleaning may also be performed when the substrate W is not in the cleaning position TP3 (for example, when the substrate W is in the polishing position TP1, or when the substrate W is not set in the polishing unit).

[0072] In the above embodiment, self-cleaning is performed after the substrate cleaning process, but the present invention is not limited thereto, and the invention may be configured to perform self-cleaning during substrate polishing or before the substrate cleaning process.

[0073] In the above embodiment, external cleaning nozzles 84 and 85 are provided corresponding to the first cleaning unit 51 and the second cleaning unit 52, respectively. However, a configuration in which a single external cleaning nozzle (third external cleaning nozzle) is provided to perform cleaning on both the first cleaning unit 51 and the second cleaning unit 52 is also possible.

[0074] The embodiments described above are intended to enable persons with ordinary skill in the art to carry out 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. The present invention is not limited to the embodiments described and should be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of symbols]

[0075] 10 Substrate Processing Equipment 13 Polishing section 13A~13D Polishing Unit 30 polishing tables 31 polishing pads 32 Top Ring 50 Auxiliary cleaning unit 51 First Washing Unit 52 Second Washing Unit 61-65 Circuit board cleaning nozzle 71-74 Assist Nozzle 81. Valve No. 1 82 Second valve W board

Claims

1. A substrate cleaning apparatus that cleans the substrate at a cleaning position after it has been polished, A first cleaning unit comprising a first cleaning nozzle that sprays cleaning liquid toward the substrate at the cleaning position, A second cleaning unit comprising a second cleaning nozzle that sprays cleaning fluid toward the substrate at the cleaning position, the second nozzle having a smaller diameter of its nozzle opening than the diameter of the nozzle opening of the first cleaning nozzle, A first valve that switches between a first open state in which cleaning fluid is sprayed from the first cleaning nozzle and a first closed state in which cleaning fluid is not sprayed from the first cleaning nozzle, A second valve that switches between a second open state in which cleaning fluid is sprayed from the second cleaning nozzle and a second closed state in which cleaning fluid is not sprayed from the second cleaning nozzle, The system includes a control unit that controls the first valve and the second valve to spray cleaning fluid from each of the first and second cleaning units, respectively. The control unit, When the substrate is not in the cleaning position, the operation of the first valve is controlled so that the first cleaning nozzle switches from the first closed state to the first open position, thereby performing a first self-cleaning procedure in which cleaning fluid is discharged from the first valve. When the substrate is not in the cleaning position, the operation of the second valve is controlled so that the second cleaning nozzle switches from the second closed state to the second open position, thereby performing a second self-cleaning procedure in which cleaning fluid is discharged from the second valve. A substrate cleaning apparatus that controls the first self-cleaning to be performed before the second self-cleaning.

2. The substrate cleaning apparatus according to claim 1, wherein the control unit controls the valves to open in the order of the first valve and the second valve, and controls the valves to close in the order of the second valve and the first valve.

3. The substrate cleaning apparatus according to claim 1, wherein the polishing surface of the substrate at the cleaning position is positioned facing downward, and the first cleaning nozzle and the second cleaning nozzle are positioned below the substrate and spray cleaning liquid upward.

4. The system further includes a flow control device that adjusts the flow rate of cleaning fluid to the first cleaning unit and the second cleaning unit, The substrate cleaning apparatus according to claim 1, wherein the flow rate of the cleaning solution during the first self-cleaning and the second self-cleaning is smaller than the flow rate of the cleaning solution when spraying the cleaning solution toward the substrate at the cleaning position.

5. The substrate cleaning apparatus according to claim 1, further comprising a first external cleaning nozzle for spraying cleaning fluid onto the first cleaning unit.

6. The substrate cleaning apparatus according to claim 1, further comprising a second external cleaning nozzle for spraying cleaning fluid onto the second cleaning unit.

7. The substrate cleaning apparatus according to claim 1, further characterized by comprising a third external cleaning nozzle that simultaneously sprays cleaning fluid to the first cleaning unit and the second cleaning unit.

8. The substrate cleaning apparatus according to claim 1, wherein the second cleaning unit is located downstream of the first cleaning unit with respect to the rotational direction of the top ring in the cleaning position.

9. The substrate cleaning apparatus according to claim 1, further comprising a third cleaning unit that sprays cleaning fluid between the membrane and the retaining ring and / or toward the retaining ring.

10. The polishing table and the top ring, A substrate polishing apparatus comprising a substrate cleaning apparatus according to any one of claims 1 to 9.

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