Liquid treatment apparatus and cleaning method

Abstract

To prevent a coating liquid adhered to an inner cup from remaining after the inner cup in a liquid processing device is cleaned.SOLUTION: In an inner cup surrounding a holding unit for holding and rotating a substrate from a side, a peripheral edge side upper surface 112 thereof is inclined downward from a top portion 113 positioned below the peripheral edge side of the held substrate toward the outside in a radial direction. A cleaning liquid discharged from a plurality of discharge holes 120 formed along a circumferential direction in the top portion 113 is made to flow down along the peripheral edge side upper surface 112 of the inner cup to which a coating liquid is attached, thereby cleaning the peripheral edge side upper surface. The discharge hole 120 is formed so as to discharge the cleaning liquid radially outward and obliquely upward. A storage chamber 121 for storing the cleaning liquid is provided in an annular shape along the circumferential direction inside the inner cup, and communicates with each of the discharge holes. In an introduction hole 122 for introducing the cleaning liquid into the storage chamber, an angle of the discharge port in the radial direction is 0° or more and up to parallel in the radial direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a liquid processing apparatus and a cleaning method.

Background Art

[0002] Patent Document 1 discloses an apparatus that performs spin coating for supplying each coating liquid such as resist to the surface of a semiconductor wafer (hereinafter referred to as "wafer"), rotating the wafer, and coating the coating liquid over the entire surface of the wafer.

[0003] Patent Document 2 discloses a coating processing apparatus having a spin chuck for adsorbing and holding a wafer, a shaft to which the spin chuck is attached, a cup base provided so as to surround the shaft, and a guide ring provided at the outer peripheral portion of the cup base and having a mountain-shaped cross-sectional shape. This coating processing apparatus further includes a cup provided so as to surround the wafer W held by the spin chuck and the guide ring. The cup can receive and recover the liquid scattered or dropped from the wafer. Patent Document 2 also discloses that a rinse liquid is supplied into the cup from a rinse liquid discharge port formed at the upper end portion of the guide ring, and the inside of the cup is cleaned.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technology according to the present disclosure ensures that no coating liquid remains attached to the inner cup after cleaning the inner cup of the liquid processing apparatus.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a liquid processing apparatus for applying a coating liquid onto a substrate, comprising: a holding unit configured to hold and rotate the substrate; a coating liquid supply unit configured to supply the coating liquid to the substrate held by the holding unit; an inner cup that surrounds the holding unit from the side, and an upper surface on the peripheral side thereof slopes downward radially outward from a top portion located below the peripheral side of the substrate held by the holding unit; the inner cup has a plurality of discharge holes formed along the circumferential direction at the top portion, and the cleaning liquid discharged from the discharge holes is caused to flow down along the upper surface on the peripheral side of the inner cup to which the coating liquid adheres, thereby cleaning the upper surface on the peripheral side; the discharge holes are formed to discharge the cleaning liquid obliquely upward and radially outward; the inner cup is provided with an annular shape along the circumferential direction inside the inner cup, communicates with each of the discharge holes, and further has a storage chamber for storing the cleaning liquid, and an introduction hole connected to the storage chamber for introducing the cleaning liquid into the storage chamber. The discharge hole is formed to discharge the cleaning liquid in a direction having an angle with respect to the radial direction passing through the discharge hole in a plan view. 。

Advantages of the Invention

[0007] According to the present disclosure, after cleaning the inner cup of the liquid processing apparatus, no coating liquid remaining on the inner cup.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] For example, in a photolithography process in a semiconductor device manufacturing process, a coating process is performed to form a coating film by applying a coating liquid onto a substrate such as a wafer.

[0010] In the above-described coating process, so-called spin coating, in which a coating liquid is supplied from a nozzle to a rotating substrate and the coating liquid is applied to the entire substrate by centrifugal force, is widely used (see Patent Documents 1 and 2).

[0011] As a liquid processing apparatus for performing spin coating, there is one including the following substrate holding portion, outer cup, and inner cup. The substrate holding portion holds and rotates the substrate, the outer cup surrounds the periphery of the substrate held by the substrate holding portion. Further, the inner cup is provided inside the outer cup and surrounds the substrate holding portion from the side, and the upper surface of its peripheral edge side is an inclined surface that slopes downward toward the radially outer side. In this liquid processing apparatus, the coating liquid scattered or dropped from the substrate is received and recovered by the outer cup, or after being received by the inner cup, it flows along the inclined surface of the upper surface of the peripheral edge side of the inner cup and drops into the outer cup and is recovered.

[0012] If the coating liquid is not recovered and remains attached to the outer cup or the inner cup, it may cause particles or the like, so it is necessary to wash and remove the coating liquid. As disclosed in Patent Document 2, by supplying a cleaning liquid into the outer cup from a discharge hole formed at the upper end portion of the inner cup, the inside of the outer cup is cleaned. Also, by supplying the cleaning liquid from the discharge hole, it is considered that the upper surface of the peripheral edge side of the inner cup is also cleaned.

[0013] By the way, in recent years, there are cases where it is required to form a coating film with a large film thickness on a substrate using a coating liquid such as a high-viscosity resist liquid. When the coating liquid has such a high viscosity, compared with the case of a low viscosity, more of the coating liquid dropped from the substrate remains on the upper surface of the peripheral edge side of the inner cup. And according to the intensive investigation by the present inventors, when the coating liquid has a high viscosity, as disclosed in Patent Document 2, even if the cleaning liquid is supplied from the discharge hole formed at the upper end portion of the guide ring and cleaned, the coating liquid adhering to the upper surface of the peripheral edge side of the inner cup may remain after cleaning.

[0014] Therefore, the technology according to the present disclosure appropriately removes the coating liquid adhering to the inner cup by washing.

[0015] Hereinafter, the liquid processing apparatus and the cleaning method according to the present embodiment will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0016] (First Embodiment) FIG. 1 and FIG. 2 are a longitudinal sectional view and a transverse sectional view schematically showing the configuration of a resist coating apparatus as a liquid processing apparatus according to the first embodiment, respectively. As shown in FIGS. 1 and 2, the resist coating apparatus 1 has a housing 10 that can be sealed inside. On the side surface of the housing 10, a carry-in / carry-out port (not shown) for the wafer W is formed.

[0017] Inside the housing 10, a spin chuck 20 is provided as a holding unit that holds and rotates the wafer W. The spin chuck 20 can be rotated at a predetermined speed by a chuck driving unit 21 having an actuator such as a motor. Further, the chuck driving unit 21 is provided with a lifting driving mechanism having an actuator such as a cylinder, and the spin chuck 20 can be lifted and lowered.

[0018] Also, inside the housing 10, a cup 30 that houses the spin chuck 20 and is exhausted from the bottom is provided. This cup 30 receives the coating liquid that has been shaken off or dropped from the wafer W held by the spin chuck 20, and guides it for discharging outside the resist coating apparatus 1. Details of this cup 30 will be described later.

[0019] As shown in FIG. 2, a rail 40 extending along the Y direction (the left-right direction in FIG. 2) is formed on the negative X direction side (the downward direction in FIG. 2) of the cup 30. The rail 40 is formed, for example, from the outside on the negative Y direction side (the left direction in FIG. 2) of the cup 30 to the outside on the positive Y direction side (the right direction in FIG. 2) of the cup 30. An arm 41 is provided on the rail 40.

[0020] The arm 41 supports a discharge nozzle 42 as a coating liquid supply unit. The discharge nozzle 42 discharges a resist liquid as a coating liquid and supplies it to the wafer W held by the spin chuck 20. The viscosity of the resist liquid supplied by the discharge nozzle 42 is, for example, 50 cp to 10,000 cP. The arm 41 is movable on the rail 40 by a nozzle drive unit 43 having an actuator such as a motor. Thereby, the discharge nozzle 42 can move from a standby unit 44 installed outside the positive Y-direction side of the cup 30 to above the central portion of the wafer W in the cup 30. Further, the arm 41 can move up and down by the nozzle drive unit 43, and the height of the discharge nozzle 42 can be adjusted.

[0021] A supply pipe 51 communicating with a supply source 50 for storing the resist liquid is connected to the discharge nozzle 42. The supply pipe 51 is provided with a supply equipment group 52 including a valve for controlling the flow of the resist liquid and a flow rate adjustment unit for adjusting the flow rate of the resist liquid.

[0022] In the resist coating apparatus 1, a supply pipe 61 communicating with a supply source 60 for storing a cleaning liquid for cleaning the cup 30 is connected to the cup 30. Specifically, the supply pipe 61 is connected to an introduction hole of an inner cup (to be described later) of the cup 30. The supply pipe 61 is provided with a supply equipment group 62 including a valve for controlling the flow of the cleaning liquid and a flow rate adjustment unit for adjusting the flow rate of the cleaning liquid.

[0023] Furthermore, the resist coating apparatus 1 is provided with a control unit U. The control unit U is a computer including, for example, a CPU and a memory, and has a program storage unit (not shown). The program storage unit stores a program for controlling the above-described nozzle drive unit 43, supply equipment group 52, supply equipment group 62, etc., to realize a resist film forming process and a cleaning process (to be described later). The above-described program may be recorded on a computer-readable storage medium and installed from the storage medium into the control unit U. Part or all of the program may be realized by dedicated hardware (circuit board).

[0024] Next, referring to FIG. 1 and using FIGS. 3 to 7, the cup 30 will be described. FIGS. 3 and 4 are a plan view and a partially enlarged view showing the outline of the configuration of the cup 30. FIG. 5 is a view for explaining an example of the direction in which the discharge hole described later discharges the cleaning liquid in a plan view. FIGS. 6 and 7 are views for explaining the reason why the direction in which the cleaning liquid is discharged from the discharge hole described later is obliquely upward.

[0025] As shown in FIG. 1, the cup 30 includes an outer cup 100 that surrounds the periphery of the wafer W held by the spin chuck 20, and is provided at a position inside the outer cup 100 and below the wafer W held by the spin chuck 20, and has an inner cup 110 that surrounds the shaft portion 20a of the spin chuck 20 from the side.

[0026] The outer cup 100 has a cylindrical outer peripheral wall 101, an inclined wall 102 that extends obliquely inward and upward over the entire circumference from the upper end of the outer peripheral wall 101, and a bottom wall 103 that extends horizontally inward over the entire circumference from the lower end of the outer peripheral wall 101 and is annular in a plan view. Further, the outer cup 100 has a cylindrical inner peripheral wall 104 that extends vertically upward from the inner peripheral end of the bottom wall 103, and a cylindrical intermediate wall 105 that extends vertically upward between the outer peripheral wall 101 and the inner peripheral wall 104 of the bottom wall 103.

[0027] A drain port 106 for discharging the liquid collected by the cup 30 is formed between the outer peripheral wall 101 and the intermediate wall 105 of the bottom wall 103, and a drain pipe 107 is connected to the drain port 106. An exhaust port 108 for exhausting the atmosphere around the periphery of the wafer W is formed between the intermediate wall 105 and the inner peripheral wall 104 of the bottom wall 103, and an exhaust pipe 109 is connected to the exhaust port 108.

[0028] The inner cup 110 has a guide portion 111 that is formed in a mountain shape in cross-section over the entire circumference and is annular in plan view. The upper surface 112 on the peripheral side of the guide portion 111 is an inclined surface that slopes downward radially outward from the top portion 113 located below the peripheral side of the wafer W held by the spin chuck 20. Hereinafter, the upper surface 112 on the peripheral side may be referred to as the inclined surface 112. Note that the "radial direction" is the radial direction centered on the central axis of the cup 30, which coincides with the rotation axis of the spin chuck 20, the central axis of the outer cup 100, and the central axis of the inner cup 110, and the same applies in the following description. By the guide portion 111 being supported by the inner peripheral wall 104 of the outer cup 100, the inner cup 110 is supported within the outer cup 100. Further, the inner cup 110 has a cylindrical vertical wall 114 that extends vertically downward from the outer peripheral end of the guide portion 111. The vertical wall 114 is located between the outer peripheral wall 101 and the intermediate wall 105 of the outer cup 100.

[0029] A gap forming an exhaust path d is formed between the vertical wall 114 and the outer peripheral wall 101 of the outer cup 100. Further, a bent path is formed by the vertical wall 114, the bottom wall 103, the intermediate wall 105, the guide portion 111, and the inner peripheral wall 104. A gas-liquid separation portion is configured by this bent path.

[0030] In the cup 30, the coating liquid scattered or dropped from the wafer W is received and collected by the outer cup 100, or after being received by the inclined surface 112 of the inner cup 110, it flows along the inclined surface 112 and drops into the outer cup 100 and is collected.

[0031] Also, as shown in FIGS. 3 and 4, the inner cup 110 is formed with discharge holes 120 for discharging a cleaning liquid. As the cleaning liquid, for example, a thinner that is a solvent of a resist liquid is used.

[0032] The discharge holes 120 are formed in plurality along the circumferential direction at the top 113 of the inner cup 110. Specifically, the discharge holes 120 are formed at predetermined intervals along the circumferential direction such that the tips thereof are positioned above the inclined surface 112. Note that the "circumferential direction" is the circumferential direction centered on the central axis of the cup 30, which coincides with the rotation axis of the spin chuck 20, the central axis of the outer cup 100, and the central axis of the inner cup 110, and the same applies to the following description.

[0033] The total number of the discharge holes 120 is, for example, 100 to 300. Each discharge hole 120 is positioned outside the outer edge of the spin chuck 20 in a plan view. Also, the flow path constituting each discharge hole 120 is, for example, cylindrical. Furthermore, the thickness of the flow path constituting the discharge holes 120 is, for example, common among the discharge holes 120.

[0034] Also, inside the guide portion 111 of the inner cup 110, a storage chamber 121 communicating with each discharge hole 120 is provided. The storage chamber 121 is provided in an annular shape along the circumferential direction. The storage chamber 121 may be divided into a plurality (for example, 2 to 5) along the circumferential direction if the number is less than the total number of the discharge holes 120.

[0035] Furthermore, the inner cup 110 is connected to an introduction hole 122 that is connected to the storage chamber 121 and introduces a cleaning liquid into the storage chamber 121. A supply pipe 61 (see FIG. 1) of the cleaning liquid is connected to the introduction hole 122. In the example of FIG. 3, one introduction hole 122 is provided for one storage chamber 121. The number of introduction holes 122 for one storage chamber 121 may be a plurality (for example, 2 to 5) if the number is less than the total number of the discharge holes 120.

[0036] The cleaning liquid supplied to the storage chamber 121 through the supply pipe 61 and the introduction hole 122 is discharged from each discharge hole 120. The cleaning liquid discharged from each discharge hole 120 flows down along the inclined surface 112 of the inner cup 110 to which the resist liquid adheres. Thereby, the resist adhering to the inclined surface 112 is removed. That is, the inclined surface 112 is cleaned.

[0037] In a plan view, the discharge direction Dt of the cleaning liquid from each discharge hole 120 is outside in the radial direction passing through the discharge hole 120. Note that the discharge direction Dt may be parallel to the radial direction Dr, or may be a direction having an angle α (α > 0°) with respect to the radial direction Dr as shown in FIG. 5. By setting the discharge direction to a direction having an angle α with respect to the radial direction Dr, the cleaning liquid can be uniformly supplied in the circumferential direction of the cup 30 to the outer peripheral edge side of the inclined surface 112 of the inner cup 110. Therefore, the possibility that the resist liquid remains attached to the inclined surface 112 of the inner cup 110 can be further reduced.

[0038] Also, as shown in FIG. 4, in a side view, the discharge direction Ds of the cleaning liquid from each discharge hole 120 is obliquely upward. In other words, the discharge direction Ds is a direction having an angle β (β > 0°) with respect to the horizontal direction Dh.

[0039] According to the intensive investigation by the inventor of the present application, when the discharge direction Ds is horizontal, after discharging a predetermined amount of the cleaning liquid from the discharge hole 120 for cleaning, the resist liquid may remain in a stripe shape along the radial direction on the outer peripheral edge side of the inclined surface 112 of the inner cup 110. This is presumably because when the discharge direction Ds is horizontal, the cleaning liquid discharged from the discharge hole 120 comes into contact with the inclined surface 112 immediately after discharge and is easily affected by the surface energy of the inclined surface 112.

[0040] If the cleaning liquid discharged from the discharge holes 120 is not in contact with the inclined surface 112 immediately after discharge and is separated from the inclined surface, unlike the above, in the space above the inclined surface 112, it spreads in the circumferential direction and then collides with the inclined surface 112, and then flows along the radial direction. In this case, as shown in FIG. 6, in the inclined surface 112, the region R1 where the cleaning liquid from each discharge hole 120 is supplied is wide on the outer peripheral edge side of the inclined surface 112. On the other hand, when the discharged liquid discharged from the discharge holes 120 is in contact with the inclined surface 112 immediately after discharge, it does not spread in the circumferential direction of the cup 30 and flows along the radial direction of the cup 30 on the inclined surface 112 as it is. In this case, as shown in FIG. 7, in the inclined surface 112, the region R2 where the cleaning liquid from each discharge hole 120 is supplied is narrow on the outer peripheral edge side of the inclined surface 112. Therefore, in the outer peripheral edge side of the inclined surface 112, regions where the supply of the cleaning liquid is insufficient are generated in a stripe shape along the radial direction, and as a result, it is considered that the resist liquid remains in a stripe shape.

[0041] Therefore, in the present embodiment, the discharge direction Ds is obliquely upward.

[0042] Next, an example of the resist coating process in the resist coating apparatus 1 will be described. The following series of processes are performed under the control of the control unit U.

[0043] In the resist coating process, first, the wafer W is sucked and held on the upper surface of the spin chuck 20. Then, the discharge nozzle 42 is moved above the center of the wafer W. Next, the wafer W is rotated at a low rotational speed (for example, 100 rpm), and during this rotation, the resist liquid is supplied from the discharge nozzle 42 onto the wafer W.

[0044] When the supply amount of the resist liquid from the discharge nozzle 42 reaches a predetermined amount, the supply of the resist liquid is stopped, and then the discharge nozzle 42 is retracted. Then, the wafer W is rotated at a higher rotational speed (for example, 3000 rpm), and the resist liquid supplied to the center of the wafer W is diffused over the entire surface of the wafer W to form a coating film with a predetermined film thickness. Next, the wafer W is rotated at a predetermined rotational speed (for example, 1000 rpm), and the coating film on the wafer W is dried.

[0045] Thereafter, the wafer W held by suction on the spin chuck 20 is carried out of the resist coating apparatus 1. Thereby, a series of processes related to the resist coating process is completed.

[0046] Subsequently, an example of the cleaning process in the resist coating apparatus 1 will be described. The following cleaning process is performed under the control of the control unit U. Note that the cleaning process is carried out, for example, in parallel with the resist coating process. Also, the cleaning process may be carried out every time the number of wafers W subjected to the resist coating process, that is, the number of processed wafers, exceeds a certain number or every time a certain period of time has elapsed, or may be carried out during maintenance.

[0047] In the cleaning process, the supply of the cleaning liquid to the storage chamber 121 is started, and the discharge of the cleaning liquid from all the discharge holes 120 is started. The discharge flow rate of the cleaning liquid from the discharge holes 120 at this time is, for example, 100 ml / min to 1000 ml / min. The cleaning liquid discharged from each discharge hole 120 spreads along the circumferential direction in the space above the inclined surface 112 as described above, then collides with the peripheral edge side of the inclined surface 112, and thereafter flows along the radial direction on the inclined surface 112. Therefore, the cleaning liquid is supplied to the entire peripheral edge side of the inclined surface 112, and all the resist liquid adhering to the peripheral edge side of the inclined surface 112 is removed.

[0048] When the discharge time of the cleaning liquid from the discharge holes 120 reaches a predetermined time (for example, 5 seconds to 300 seconds), the supply of the cleaning liquid to the storage chamber 121 is stopped, and the cleaning process ends.

[0049] As described above, in this embodiment, a plurality of discharge holes 120 for discharging the cleaning liquid outward in the radial direction are provided at the top 113 of the inner cup 110 along the circumferential direction. And the discharge direction of the cleaning liquid from each discharge hole 120 is obliquely upward. Therefore, the cleaning liquid discharged from each discharge hole 120 flies away from the inclined surface 112 of the inner cup 110 and is not affected by the surface energy of the inclined surface 112. Thus, the cleaning liquid discharged from the discharge holes 120 spreads in the circumferential direction in the space above the inclined surface 112 and then flows on the inclined surface 112. Therefore, the cleaning liquid can be supplied to the entire region on the outer peripheral edge side, which is the region where the resist liquid mainly adheres on the inclined surface 112, and the resist liquid can be completely removed from the inclined surface 112. That is, according to this embodiment, the coating liquid adhering to the inclined surface 112 of the inner cup 110 can be appropriately removed by cleaning.

[0050] (Second Embodiment) FIG. 8 is a longitudinal sectional view schematically showing the configuration of a resist coating apparatus as a liquid processing apparatus according to the second embodiment. In the resist coating apparatus 1a of FIG. 8, a supply pipe 201 communicating with a supply source 200 for storing nitrogen (N2) gas as an inert gas is connected to the supply pipe 61. That is, not only the cleaning liquid but also nitrogen gas is introduced into the storage chamber 121 (see FIG. 3 etc.) through the introduction hole 122 (see FIG. 3 etc.) to which the supply pipe 61 is connected.

[0051] The supply pipe 201 is provided with a supply device group 202 including a valve for controlling the flow of nitrogen gas and a flow rate adjustment unit for adjusting the flow rate of nitrogen gas. The supply device group 202 is controlled by the control unit U.

[0052] FIGS. 9 to 14 are timing charts for explaining examples of supplying the cleaning liquid and nitrogen gas.

[0053] (Example 1 of Supplying Cleaning Liquid and Nitrogen Gas) For example, under the control of the control unit U, the supply of the cleaning liquid to the storage chamber 121 and the supply of nitrogen gas to the storage chamber 121 are carried out simultaneously as shown in FIG. 9. At this time, under the control of the control unit U, both the supply flow rate of the cleaning liquid to the storage chamber 121 and the supply flow rate of nitrogen gas to the storage chamber 121 are made constant. In this way, by simultaneously supplying nitrogen gas together with the cleaning liquid to the storage chamber 121, the cleaning liquid can be discharged from the discharge holes 120 (see FIG. 3 etc.) at a higher flow rate. The longer the moving distance of the cleaning liquid discharged from the discharge holes 120 in the space above the inclined surface 112, the more it spreads in the circumferential direction and then collides with the inclined surface 112 of the inner cup 110. And when the flow rate of the cleaning liquid discharged from the discharge holes 120 is large as described above, the cleaning liquid moves further in the space above the inclined surface 112. Therefore, by supplying nitrogen gas together with the cleaning liquid to the storage chamber 121, the cleaning liquid can be supplied from each discharge hole 120 to a wider region on the outer peripheral edge side of the inclined surface 112 in the circumferential direction.

[0054] (Example of supply of cleaning liquid and nitrogen gas 2) In this example, similar to Supply Example 1, the supply of the cleaning liquid to the storage chamber 121 and the supply of nitrogen gas to the storage chamber 121 are carried out simultaneously, and the supply flow rate of nitrogen gas to the storage chamber 121 is constant. However, in this example, the supply flow rate of the cleaning liquid to the storage chamber 121 is alternately switched between a large flow rate and a small flow rate as shown in FIG. 10. Specifically, it is as follows.

[0055] When the supply of the cleaning liquid and the supply of nitrogen gas are carried out simultaneously as in Supply Example 1 and Supply Example 2, even if the supply flow rate of the cleaning liquid is constant, a peak in the flow rate of the cleaning liquid discharged from the discharge holes 120 occurs at a predetermined cycle (each timing when the amount of cleaning liquid in the storage chamber 121 is maximum). And in this example, at the timing when the peak in the flow rate of the cleaning liquid discharged from the discharge holes 120 occurs, that is, at the timing when the discharge of the cleaning liquid from the discharge holes 120 occurs, the supply flow rate of the cleaning liquid to the storage chamber 121 is switched to a large flow rate. Also, thereafter, at the timing when the discharge of the cleaning liquid from the discharge holes 120 is interrupted or when it becomes below a predetermined flow rate, the supply flow rate of the cleaning liquid to the storage chamber 121 is switched to a small flow rate.

[0056] When the supply of the cleaning liquid and the supply of nitrogen gas are performed simultaneously as in Supply Example 1 and Supply Example 2, flow interference occurs between the supply flow rate of the cleaning liquid and the supply flow rate of the nitrogen gas, and the flow velocity at the peak of the cleaning liquid discharged from the discharge hole 120 decreases, and the flow rate of the cleaning liquid discharged from the discharge hole 120 at the peak may decrease. On the other hand, in Cleaning Example 2, since the supply flow rate of the cleaning liquid to the storage chamber 121 becomes a large flow rate at the timing when the peak of the flow velocity of the cleaning liquid discharged from the discharge hole 120 occurs, it is possible to prevent the decrease in the flow rate of the cleaning liquid discharged from the discharge hole 120 at the above peak.

[0057] (Supply Example 3 of Cleaning Liquid and Nitrogen Gas) In this example, similar to Supply Example 1, the supply of the cleaning liquid to the storage chamber 121 and the supply of nitrogen gas to the storage chamber 121 are performed simultaneously, and the supply flow rate of the cleaning liquid to the storage chamber 121 is constant. However, in this example, the supply flow rate of nitrogen gas to the storage chamber 121 is alternately switched between a large flow rate and a small flow rate as shown in FIG. 11. Specifically, it is as follows.

[0058] In this example, at the timing when the peak of the flow velocity of the cleaning liquid discharged from the discharge hole 120 occurs, that is, at the timing when the cleaning liquid is discharged from the discharge hole 120, the supply flow rate of nitrogen gas to the storage chamber 121 is switched to a large flow rate. Further, thereafter, at the timing when the discharge of the cleaning liquid from the discharge hole 120 is interrupted, etc., the supply flow rate of nitrogen gas to the storage chamber 121 is switched to a small flow rate.

[0059] In Cleaning Example 3, since the supply flow rate of nitrogen gas to the storage chamber 121 becomes a large flow rate at the timing when the peak of the flow velocity of the cleaning liquid discharged from the discharge hole 120 occurs, it is possible to prevent the decrease in the flow rate of the cleaning liquid discharged from the discharge hole 120 at the above peak.

[0060] (Supply Example 4 of Cleaning Liquid and Nitrogen Gas) In this supply example, under the control of the control unit U, the supply of the cleaning liquid to the storage chamber 121 and the supply of nitrogen gas to the storage chamber 121 are alternately performed as shown in FIG. 12. At this time, under the control of the control unit U, the supply pressure of the nitrogen gas is made higher than the supply pressure of the cleaning liquid. At the same time, under the control of the control unit U, both the supply flow rate of the cleaning liquid to the storage chamber 121 and the supply flow rate of the nitrogen gas to the storage chamber 121 are made constant.

[0061] As in this example, by alternately supplying the cleaning liquid to the storage chamber 121 and supplying the nitrogen gas to the storage chamber 121 and making the supply pressure of the nitrogen gas high, the cleaning liquid can be discharged from the discharge hole 120 at a higher flow rate. Also, by performing alternately as in this example, the above-described flow rate interference does not occur, so that the cleaning liquid can be efficiently discharged from the discharge hole 120 at a large flow rate.

[0062] (Supply Example 5 of Cleaning Liquid and Nitrogen Gas) In this example, similar to Supply Example 4, the supply of the cleaning liquid to the storage chamber 121 and the supply of the nitrogen gas to the storage chamber 121 are alternately performed, and the supply flow rate of the nitrogen gas to the storage chamber 121 is constant. However, in this example, the supply flow rate of the cleaning liquid to the storage chamber 121 changes as shown in FIG. 13. Specifically, the supply flow rate of the cleaning liquid is set to a small flow rate and gradually increased until a predetermined time has elapsed after switching from the supply of nitrogen gas to the supply of the cleaning liquid. Thereby, it is possible to prevent the cleaning liquid from flowing back into the supply pipe 201 leading to the nitrogen gas supply source 200. Also, the supply flow rate of the cleaning liquid is set to a large flow rate in the latter half of the cleaning liquid supply stage. Thereby, it is possible to remove the bubbles in the storage chamber 121 of the inner cup 110.

[0063] (Supply Example 6 of Cleaning Liquid and Nitrogen Gas) In this example, similar to Supply Example 4, the supply of the cleaning liquid to the storage chamber 121 and the supply of nitrogen gas to the storage chamber 121 are alternately performed, and the supply flow rate of the cleaning liquid to the storage chamber 121 is constant. However, in this example, the supply flow rate of nitrogen gas to the storage chamber 121 changes as shown in FIG. 14. Specifically, the supply flow rate of the nitrogen gas is set to a large flow rate in the first half of the nitrogen gas supply stage and a small flow rate in the second half.

[0064] When the supply of the cleaning liquid and the supply of nitrogen gas are alternately performed as in Supply Examples 4 to 6, a liquid film of the cleaning liquid may be formed on the opening at the tip of the discharge hole 120 at the end of the nitrogen gas supply stage. When nitrogen gas is supplied in a state where a liquid film of the cleaning liquid is formed, droplets of the cleaning liquid are discharged from the discharge hole 120 and float in the housing 10. The floating droplets of the cleaning liquid may have an adverse effect on the coating film of the resist liquid on the wafer W when the cleaning process and the resist coating process are performed in parallel.

[0065] On the other hand, in this example, as described above, the supply flow rate of nitrogen gas is set to a small flow rate in the second half of the nitrogen gas supply stage. Therefore, even if a liquid film of the cleaning liquid is formed on the opening at the tip of the discharge hole 120 at the end of the nitrogen gas supply stage and droplets of the cleaning liquid are generated, the generated droplets of the cleaning liquid will have a larger particle size. Therefore, the droplets of the cleaning liquid do not float in the housing 10 for a long time. As a result, it is possible to reduce the possibility that the droplets of the cleaning liquid scattered from the discharge hole 120 affect the coating film of the resist liquid on the wafer W.

[0066] Also, as in this example, setting the supply flow rate of nitrogen gas to a large flow rate in the first half of the nitrogen gas supply stage means setting the supply flow rate of the nitrogen gas to a large flow rate in the first half of the discharge stage of the cleaning liquid from the discharge holes 120. Further, in the first half of the discharge stage of the cleaning liquid from the discharge holes 120, the cleaning liquid is discharged at a large flow rate. By setting the supply flow rate of the nitrogen gas to a large flow rate and increasing the flow velocity of the cleaning liquid discharged from the discharge holes 120 in the first half of the discharge stage of the cleaning liquid when the cleaning liquid is discharged at such a large flow rate, a larger amount of the cleaning liquid can be supplied to a wider area on the outer peripheral edge side of the inclined surface 112. That is, the supply distribution of the cleaning liquid can be further improved.

[0067] (Modification example of the inner cup) FIG. 15 is a partially enlarged cross-sectional view for explaining another example of the discharge holes. In the above example, the flow paths constituting each discharge hole 120 were columnar. That is, the flow paths constituting each of the lower discharge holes 120 had a uniform thickness from the base end to the tip end. Instead of this, as shown in FIG. 15, the flow paths constituting each discharge hole 120a may be thinner at the tip end than at the base end side. Thereby, the cleaning liquid can be discharged from each discharge hole 120a at a higher flow velocity.

[0068] Also, in the above example, the thickness of the flow paths constituting the discharge holes 120 was common among the discharge holes 120. Instead of this, the thickness of the flow paths constituting the discharge holes 120 may be made different according to the distance from the discharge holes 120 to the introduction holes 122. Specifically, the thickness of the flow paths constituting the discharge holes 120 may be made thicker as the distance from the discharge holes 120 to the introduction holes 122 is farther. Thereby, even from the discharge holes 120 where the distance to the introduction holes 122 is far and the discharge pressure, that is, the flow velocity at the time of discharge tends to be low, the flow velocity at the time of discharge can be increased. Therefore, the flow velocity of the cleaning liquid discharged from the discharge holes 120 can be made uniform among the discharge holes 120. As a result, the possibility of unevenness occurring in the supply distribution of the cleaning liquid to the inclined surface 112 can be further reduced.

[0069] Furthermore, the upward diagonal ejection angle of the cleaning liquid by the ejection holes 120 may be varied according to the distance from the ejection holes 120 to the introduction holes 122. Specifically, the upward diagonal ejection angle of the cleaning liquid by the ejection holes 120 may be increased as the distance from the ejection holes 120 to the introduction holes 122 becomes greater. The ejection holes 120 with a greater distance to the introduction holes 122 tend to have a lower ejection pressure, i.e., a lower flow velocity during ejection, and the ejected cleaning liquid is more susceptible to the influence of the surface energy of the inclined surface 112. In contrast, as in this example, for the ejection holes 120 with a greater distance to the introduction holes 122, by increasing the upward diagonal ejection angle of the cleaning liquid, even the cleaning liquid ejected from the ejection holes 120 is less susceptible to the influence of the surface energy. Therefore, the area of the region where each ejection hole 120 supplies the cleaning liquid to the outer peripheral edge side of the inclined surface 112 can be made uniform among the ejection holes 120. As a result, the possibility of unevenness occurring in the supply distribution of the cleaning liquid to the inclined surface 112 can be further reduced.

[0070] FIG. 16 is a partial cross-sectional view showing the schematic configuration of another example of the inner cup. As described above, droplets of the cleaning liquid may be released from the ejection holes 120. To prevent the diffusion of these droplets of the cleaning liquid, a shielding plate 300 may be provided on the inclined surface 112. More specifically, the shielding plate 300 is for preventing the droplets of the cleaning liquid released from the ejection holes 120 from diffusing to the inner peripheral side of the ejection holes 120. The shielding plate 300 is formed, for example, to extend horizontally from a position above the ejection holes 120 on the inclined surface 112. The length of the shielding plate 300 is such that a mass of the cleaning liquid ejected from the ejection holes 120 during normal times does not collide with the tip of the shielding plate 300. Note that "normal times" means a period during which the release of droplets of the cleaning liquid does not occur.

[0071] FIG. 17 is a partial cross-sectional view showing the schematic configuration of another example of the inner cup. FIG. 18 is a diagram showing the schematic of a communication hole described later. As shown in FIG. 17, the storage chamber 121a may be divided by a partition wall 400 that divides the inside of the storage chamber 121a into two regions along the fluid flow into two buffer areas 410 and 411 that are annular in a plan view along the circumferential direction. In this case, a plurality of communication holes 401 are formed in the partition wall 400. The communication holes 401 communicate the upstream buffer (hereinafter sometimes referred to as "primary buffer") 410 and the downstream buffer (hereinafter sometimes referred to as "secondary buffer") 411 separated by the partition wall 400.

[0072] For example, as shown in FIG. 18, the communication holes 401 are formed in a slit shape that is long in the circumferential direction and short in the radial direction. Further, the communication holes 401 are provided at predetermined intervals along the circumferential direction over the entire circumference. Note that the number of the communication holes 401 is, for example, a number such that the total length of the communication holes 401 in the circumferential direction is 180° or more.

[0073] As described above, by providing the two buffers 410 and 411 and providing the communication holes 401 at predetermined intervals along the circumferential direction over the entire circumference in the partition wall 400 that separates these buffers 410 and 411, the following effects are obtained. That is, the cleaning liquid is supplied to the secondary buffer 411 communicating with the discharge hole 120 from the primary buffer 410 with a uniform pressure in the circumferential direction. Therefore, the cleaning liquid is discharged from the discharge hole 120 with a uniform pressure, that is, a uniform flow rate in the circumferential direction. Accordingly, the cleaning liquid can be supplied uniformly in the circumferential direction to the outer peripheral edge side of the inner cup 110a.

[0074] FIG. 19 is a diagram showing another example of the communication hole. As shown in FIG. 19, the shape of the communication hole 401a may be a frustum of a cone. Also in the case of this shape, the communication holes 401a are provided at predetermined intervals along the circumferential direction over the entire circumference.

[0075] FIG. 20 is a partial cross-sectional view showing an outline of the configuration of another example of the inner cup. In the example of FIG. 18, the storage chamber 121a was divided into two buffers 410 and 411. The storage chamber is not limited to this example and may be divided into three or more buffers. For example, in the inner cup 110b of FIG. 20, the storage chamber 121b is divided into three buffers 500 to 502, and these buffers 500 to 502 are stacked in the horizontal direction in the figure.

[0076] A partition wall 510 is provided between the uppermost buffer 500 and the intermediate buffer 501, and a partition wall 511 is provided between the intermediate buffer 501 and the lowermost buffer 502. Further, a communication hole 512 for communicating the buffer 500 and the buffer 501 is provided in the partition wall 510, and a communication hole 513 for communicating the buffer 501 and the buffer 502 is provided in the partition wall 511. Among the communication holes 512 and 513, at least the communication hole 513 is provided at predetermined intervals along the circumferential direction of the cup 30 over the entire circumference, similar to the communication hole 401 in FIG. 17. Hereinafter, it is assumed that the communication hole 512 is formed in an annular shape in plan view.

[0077] And it is preferable that the through directions of the communication hole 512 and the communication hole 513 are not aligned on the same straight line. This is because, when they are aligned on the same straight line, the cleaning liquid is supplied to the lowermost buffer 502 communicating with the discharge hole 120 from the communication hole 513 at a higher pressure than when they are not aligned, and as a result, the discharge pressure of the cleaning liquid from the discharge hole 120 becomes more non-uniform in the circumferential direction of the cup 30.

[0078] Also, it is preferable that the introduction direction of the cleaning liquid into the storage chamber 121b by the introduction hole 122 and the through direction of the communication hole 512 provided in the uppermost partition wall 510 are not aligned on the same straight line. This is because, when they are aligned on the same straight line, there is a possibility that the discharge pressure of the cleaning liquid from the discharge hole 120 closer to the introduction hole 122 becomes higher than that from the other discharge holes 120.

[0079] Similarly, when the number of buffers is two as in FIG. 17, it is preferable that the introduction direction of the cleaning liquid into the storage chamber 121a by the introduction hole 122 and the through direction of the communication hole 401 are not aligned on the same straight line. The cleaning liquid is supplied to the secondary buffer 411 from the communication hole 401 penetrating in the direction aligned with the introduction direction of the cleaning liquid by the introduction hole 122 at a higher pressure than from the other communication holes 401, and as a result, the discharge pressure of the cleaning liquid from the discharge hole 120 becomes non-uniform in the circumferential direction of the cup 30.

[0080] FIG. 21 is a partial cross-sectional view showing the configuration of another example of the inner cup. In the inner cup 110c of FIG. 21, a recess 520 that is recessed downward is formed at the bottom of a buffer 500 against which nitrogen gas introduced into the storage chamber 121c collides when it advances along the buffer 500 on the most upstream side. Therefore, the nitrogen gas introduced into the storage chamber 121c enters the recess 520, the flow rate decreases, and then it is supplied to the buffer 501. Accordingly, it is possible to prevent the discharge pressure of the cleaning liquid from the discharge holes 120 from becoming non-uniform in the circumferential direction due to the high flow rate of the cleaning liquid supplied to the buffer 501.

[0081] Also, in the inner cup 110c of FIG. 21, a recess 521 that is notched so as to be recessed upward is formed at the lower end of the partition wall 510. The recesses 521 are provided at predetermined intervals over the entire circumference along the circumferential direction of the cup 30.

[0082] By providing such recesses 521, the nitrogen gas introduced into the storage chamber 121 escapes only from these recesses 521. Therefore, the distribution of the nitrogen gas can be improved.

[0083] Note that, unlike the above example, separate from the discharge holes of the cleaning liquid, discharge holes for an inert gas such as nitrogen gas may be provided above the discharge holes of the cleaning liquid on the inclined surface 112 to assist the diffusion of the cleaning liquid with the inert gas.

[0084] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and gist of the appended claims.

Description of Reference Numerals

[0085] 1 Resist Coating Apparatus 1a Resist Coating Apparatus 20 Spin Chuck 42 Discharge Nozzle 100 Outer Cup 110 Inner Cup Inner cup 110a Inner cup 110c Peripheral upper surface (inclined surface) 112 Top 113 Discharge hole 120 Discharge hole 120a Wafer W

Claims

1. A liquid processing apparatus that applies a coating liquid onto a substrate, comprising: a holder that holds and rotates the substrate; a coating liquid supply unit that supplies a coating liquid to the substrate held by the holding unit; an inner cup that laterally surrounds the holding portion and has an upper peripheral surface that slopes downward from a top portion located below the peripheral side of the substrate held by the holding portion toward an outer side in a radial direction; the inner cup has a plurality of discharge holes formed in the top portion along a circumferential direction, the cleaning liquid discharged from the discharge hole is caused to flow down along the peripheral upper surface of the inner cup to which the coating liquid is attached, thereby cleaning the peripheral upper surface; The discharge hole is formed to discharge the cleaning liquid radially outward and obliquely upward, and the inner cup is a storage chamber that is provided in an annular shape along a circumferential direction inside the inner cup, that communicates with each of the discharge holes, and that stores the cleaning liquid; An introduction hole connected to the storage chamber for introducing a cleaning liquid into the storage chamber, The liquid treatment device, wherein the discharge hole is formed so as to discharge the cleaning liquid in a direction having an angle with respect to a radial direction passing through the discharge hole in a plan view.

2. The liquid treatment device according to claim 1 , wherein the flow passage constituting the discharge hole has a tip end which is thinner than a base end side.

3. 3. The liquid treatment apparatus according to claim 1, further comprising a shielding plate disposed above the discharge holes for preventing the washing liquid from being dispersed in droplets from the discharge holes.

4. 4. The liquid treatment device according to claim 1, wherein a width of a flow path constituting said discharge hole varies depending on a distance from said discharge hole to said introduction hole.

5. The storage chamber is divided into a plurality of annular buffers along a circumferential direction by partition walls that divide the interior of the storage chamber into a plurality of regions along a fluid flow, 5. The liquid treatment apparatus according to claim 1, wherein the partition is provided with a communication hole that allows the buffers separated by the partition to communicate with each other.

6. The liquid treatment apparatus according to claim 5 , wherein the partition wall has a plurality of the communication holes provided along a circumferential direction.

7. 7. The liquid treatment device according to claim 6, wherein when the number of the buffers is three, the communication hole provided in one of the partition walls and the communication hole provided in the other of the partition walls are not aligned in a straight line in a penetrating direction.

8. 8. The liquid treatment apparatus according to claim 6, wherein a direction in which the cleaning liquid is introduced through the inlet and a direction in which the communication hole provided in the partition wall on the most upstream side penetrate the partition wall are not aligned on a straight line.

9. 9. The liquid treatment apparatus according to claim 1, wherein an inert gas is also introduced into the storage chamber through the introduction hole.

10. The supply of the cleaning liquid to the storage chamber and the supply of the inert gas to the storage chamber are performed simultaneously, The liquid treatment apparatus according to claim 9 , wherein a flow rate of the cleaning liquid supplied to the storage chamber and a flow rate of the inert gas supplied to the storage chamber are constant.

11. The supply of the cleaning liquid to the storage chamber and the supply of the inert gas to the storage chamber are performed simultaneously, 10. The liquid treatment apparatus according to claim 9, wherein the supply flow rate of the inert gas to the storage chamber is constant, and the supply flow rate of the cleaning liquid to the storage chamber is alternately switched between a large flow rate and a small flow rate.

12. The supply of the cleaning liquid to the storage chamber and the supply of the inert gas to the storage chamber are performed simultaneously, 10. The liquid treatment apparatus according to claim 9, wherein the supply flow rate of the cleaning liquid to the storage chamber is constant, and the flow rate of the inert gas to the storage chamber is alternately switched between a large flow rate and a small flow rate.

13. The supply of the cleaning liquid to the storage chamber and the supply of the inert gas to the storage chamber are alternately performed, The liquid treatment apparatus according to claim 9 , wherein a supply flow rate of the cleaning liquid to the storage chamber and a flow rate of the inert gas to the storage chamber are constant.

14. The supply of the cleaning liquid to the storage chamber and the supply of the inert gas to the storage chamber are alternately performed, 10. The liquid treatment apparatus of claim 9, wherein the supply flow rate of the inert gas to the reservoir is constant, and the flow rate of the cleaning liquid to the reservoir is variable.

15. The supply of the cleaning liquid to the storage chamber and the supply of the inert gas to the storage chamber are alternately performed, 10. The liquid treatment apparatus of claim 9, wherein the supply flow rate of the cleaning liquid to the storage chamber is constant, and the flow rate of the inert gas to the storage chamber is variable.

16. 1. A cleaning method for cleaning a liquid processing apparatus that applies a coating liquid onto a substrate, comprising the steps of: The liquid treatment device comprises: a holder that holds and rotates the substrate; a coating liquid supply unit that supplies a coating liquid to the substrate held by the holding unit; an inner cup that laterally surrounds the holding portion and has an upper peripheral surface that slopes downward from a top portion located below the peripheral side of the substrate held by the holding portion toward an outer side in a radial direction; a step of discharging a cleaning liquid from a plurality of discharge holes formed in the top of the inner cup along a circumferential direction, and causing the cleaning liquid to flow down along a peripheral upper surface of the inner cup, thereby cleaning the coating liquid adhering to the peripheral upper surface; The inner cup is a storage chamber that is provided in an annular shape along a circumferential direction inside the inner cup, that communicates with each of the discharge holes, and that stores the cleaning liquid; An introduction hole connected to the storage chamber for introducing a cleaning liquid into the storage chamber, The cleaning method, wherein the cleaning step includes a step of discharging the cleaning liquid from the discharge hole in a direction radially outward and obliquely upward, the direction being angled with respect to a radial direction passing through the discharge hole in a plan view.

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