Airflow forming device

Abstract

To suppress variations in film thickness of substrates after liquid processing by suppressing changes in wind speed in a processing space.SOLUTION: An airflow forming unit 2 is an airflow forming unit that generates an airflow from above a coating processing portion 100 downward toward a processing space PS of the coating processing portion 100. The airflow forming unit 2 includes a gas supply portion 10 that blows out introduced gas downward from a blowout surface 12a facing the processing space PS. The airflow forming unit 2 includes an airflow control plate 50 arranged below the blowout surface 12a and above the processing space PS so as to surround an opening 300 directly above the processing space PS. The airflow control plate 50 forms an annular strong airflow forming area SA around the opening 300 in which a stronger airflow than in the area outside of the opening is generated for the gas blown downward from the blowout surface 12a.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an air flow forming device.

Background Art

[0002] An air flow forming device that generates an air flow (downflow) from above the liquid treatment unit toward the treatment space of the liquid treatment unit is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, depending on the device environmental conditions, the air flow toward the above-described treatment space may not be stable, and as a result, the film thickness of the substrate after liquid treatment may vary (the film thickness varies between substrates). For example, depending on the exhaust state of adjacent coating cups or the device positive pressure value, which is a factor of daily difference, the air flow toward the treatment space may not be stable, and the film thickness of the substrate may vary. In particular, in chemical solutions and processes with high air flow sensitivity, the variation in film thickness due to unstable air flow becomes显著.

[0005] The present disclosure has been made in view of the above circumstances, and provides an air flow forming device capable of suppressing variations in the film thickness of a substrate after liquid treatment by suppressing changes in the upstream wind speed of the treatment space, which is a parameter of air flow changes.

Means for Solving the Problems

[0006] An airflow forming apparatus relating to one aspect of the present disclosure is an airflow forming apparatus that generates an airflow downward from above a liquid processing unit toward the processing space of the liquid processing unit, comprising: a gas supply unit that blows out introduced gas downward from a first surface facing the processing space; and an airflow forming unit that is positioned below the first surface and above the processing space, surrounding an opening directly above the processing space, and forms an annular strong airflow forming region around the opening with respect to the gas blown out downward from the first surface, where a stronger airflow is generated around the opening than in the outer region. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an airflow forming apparatus that can suppress variations in the film thickness of the substrate after liquid treatment by suppressing changes in air velocity in the processing space. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a vertical cross-sectional view showing a schematic configuration of a resist coating apparatus including an airflow forming unit according to this embodiment. [Figure 2] Figure 2 is a bottom view of the airflow control plate. [Figure 3] Figure 3(a) is a vertical cross-sectional view of the gas supply unit and airflow control plate, and Figure 3(b) is a top view of the airflow control plate. [Figure 4] Figure 4 illustrates the region where strong airflow is formed. [Figure 5] Figure 5 shows the center air velocity for each positive pressure value of the device. [Figure 6] Figure 6 shows the substrate film thickness for each positive pressure value of the apparatus. [Modes for carrying out the invention]

[0009] Figure 1 is a vertical cross-sectional view showing the schematic configuration of the resist coating apparatus 1 according to this embodiment. The resist coating apparatus 1 is an apparatus (substrate processing apparatus) included in a substrate processing system that performs the formation of a photosensitive film on a substrate, exposure of the photosensitive film, and development of the photosensitive film. Examples of substrates to be processed include semiconductor wafers, glass substrates, mask substrates, or FPDs (Flat Panel Displays). The substrate also includes semiconductor wafers and the like on which a film has been formed in a preceding process. The resist coating apparatus 1 performs a process to form a resist film on the surface of the substrate before exposure processing by an exposure apparatus (not shown) included in the substrate processing system. More specifically, the resist coating apparatus 1 supplies a coating solution for forming a resist film to the surface of the substrate to form the pre-bake resist film. After forming the pre-bake resist film on the surface of the substrate, the resist coating apparatus 1 supplies a removal solution to the peripheral edge of the substrate to remove the peripheral edge of the pre-bake resist film.

[0010] As shown in Figure 1, the resist coating apparatus 1 is composed of a coating processing unit 100 (liquid processing unit) and an airflow forming unit 2 (airflow forming apparatus).

[0011] The coating processing unit 100 has two processing units 100a and 100b. The two processing units 100a and 100b are arranged side by side and have the same configuration. Each of the two processing units 100a and 100b includes a spin chuck (not shown) and a cup 101.

[0012] The spin chuck (not shown) is a rotating holding unit that holds the substrate W horizontally by adsorption to the center of the back surface and rotates the substrate W. The spin chuck is connected to a rotation drive mechanism (not shown) via a rotation axis (not shown). The spin chuck is configured to rotate freely around a vertical axis while holding the substrate W via the rotation drive mechanism, and is set so that the center of the substrate W is located on the rotation axis. The rotation drive mechanism controls the rotation speed of the spin chuck by receiving a control signal from a control unit (not shown).

[0013] Cup 101 has an opening on its upper side that surrounds the substrate W on the spin chuck. The area surrounded by cup 101 is the processing space PS for coating the substrate W. An exhaust pipe (not shown) is provided below cup 101. Three lifting pins (not shown) are also provided inside cup 101. The lifting pins can be raised and lowered by a lifting mechanism (not shown), allowing the substrate W to be transferred between the spin chuck and a substrate transport mechanism (not shown) that transports the substrate W to the resist coating apparatus 1. Furthermore, the coating processing unit 100 has various components (not shown) for supplying resist liquid to the substrate W.

[0014] The airflow forming unit 2 is configured to generate an airflow from above the coating processing unit 100 toward the processing space PS of the coating processing unit 100. The airflow forming unit 2 includes a gas supply unit 10, an airflow control plate 50 (airflow forming unit), and a plurality of spacers 70 (see Figures 3(a) and 3(b)).

[0015] The gas supply unit 10 is configured to blow the introduced gas toward the processing space PS. The gas supply unit 10 includes a blowing unit 11 and a ULPA (Ultra Low Penetration Air) filter 12.

[0016] The discharge unit 11 is a flat, box-shaped component, with an opening on its bottom surface forming the discharge surface 11a. An introduction hole for introducing gas is formed on the side of the discharge unit 11. A ULPA filter 12 is attached to the bottom of the discharge unit 11.

[0017] The ULPA filter 12 is a filter that removes fine particles in the gas. The ULPA filter 12 removes particles in the gas flowing downward from the blowing surface 11a of the blowing unit 11, and blows out the gas downward from its lower surface, which is the blowing surface 12a (the first surface). At the blowing surface 12a, the rectified gas flows out directly from the punched openings. The air volume of the gas blown out from the blowing surface 12a is generally constant regardless of the region. That is, there is no difference in the air volume of the gas from the ULPA filter 12 between the cups 101 of the two processing units 100a and 100b.

[0018] The airflow control plate 50 is disposed below the blowing surface 12a of the ULPA filter 12 and above the processing spaces PS of the processing units 100a and 100b. The airflow control plate 50 is disposed so as to surround the opening 300 directly above the processing space PS. The airflow control plate 50 is an airflow forming portion that forms an annular strong airflow formation region SA (see FIGS. 1 and 4; details will be described later) in which a stronger airflow is generated in the periphery of the opening 300 than in the outer region for the gas blown downward from the blowing surface 12a. In a plan view, the region of the opening 300 is narrower than the region of the substrate W disposed in the processing space PS. That is, the opening 300 is formed only in a region inside the outer edge of the substrate W in a plan view. The details of the airflow control plate 50 will be described while referring also to FIGS. 2 to 4. FIG. 2 is a bottom view of the airflow control plate 50. FIG. 3(a) is a vertical cross-sectional view of the gas supply unit 10 and the airflow control plate 50, and FIG. 3(b) is a top view of the airflow control plate 50. FIG. 4 is a diagram for explaining the strong airflow formation region.

[0019] As shown in Figure 2, the airflow control plate 50 is positioned to surround the openings 300, 300, which correspond to the processing units 100a, 100b. As shown in Figures 2 and 3(a), the airflow control plate 50 has an annular wall portion 51 that extends vertically to surround the opening 300, and a bottom portion 52 that is continuous with the lower end of the wall portion 51 and extends horizontally to face the outlet surface 12a of the ULPA filter 12. The bottom portion 52 extends horizontally to face all areas below the outlet surface 12a except the area corresponding to the opening 300.

[0020] As shown in Figure 3(a), the wall portion 51 extends vertically so that a narrow gap 51a is formed between its upper end and the outlet surface 12a of the ULPA filter 12. The narrow gap 51a is, for example, about 50% of the distance between the outlet surface 12a and the bottom portion 52, and specifically, it may be about 1.5 to 4.5 mm in length. With this configuration, the gas that has accumulated between the outlet surface 12a and the bottom portion 52 is blown out from the narrow gap 51a towards the opening 300 (see Figure 1). Due to the pressure loss in the narrow gap 51a, the flow velocity of the airflow formed by the gas blown out from the narrow gap 51a increases, and an annular strong airflow region SA is formed around the opening 300, where a stronger airflow is generated than in the outer region (see Figures 1 and 4).

[0021] As shown in FIGS. 3(a) and 3(b), the airflow control plate 50 is fixed to the ULPA filter 12 via a plurality of spacers 70. The upper end of the spacer 70 is connected to the blowing surface 12a of the ULPA filter 12, and the lower end is connected to the bottom portion 52. The plurality of spacers 70 have the same height in the vertical direction. As shown in FIG. 3(b), each spacer 70 is provided at regular intervals along an annular wall portion 51 erected so as to surround the opening 300. Further, the spacer 70 is provided not only in the region along the wall portion 51 but also in each region of the bottom portion 52 so that the separation distance between the spacers 70 does not become too large (see FIG. 3(b)). Thus, by providing the plurality of spacers 70 having the same height at the bottom portion 52 evenly, it is possible to make the size of the space in which the gas between the blowing surface 12a and the bottom portion 52 accumulates constant, and it is possible to suppress the occurrence of differential pressure in each region and the variation of the airflow.

[0022] Furthermore, as shown in Figure 2, the bottom portion 52 has a plurality of holes 55 formed therein that allow gas to be sent downward. The bottom portion 52 has a first region 52a (the central region) which is a region continuous with the wall portion 51, and a second region 52b which is a region outside the first region 52a. With respect to the plurality of holes 55 described above, the first opening ratio, which is the proportion of the plurality of holes 55 that occupy the first region 52a, is lower than the second opening ratio, which is the proportion of the plurality of holes 55 that occupy the second region 52b. In other words, when comparing the first region 52a and the second region 52b under the condition of having the same area, the first region 52a has a smaller area of ​​holes 55 that allow gas to escape downward. As a result, the flow velocity of the airflow formed by the gas blown out from the first region 52a becomes relatively faster, and a strong airflow formation region SA is formed near the wall portion 51 (i.e., around the opening 300) (see Figures 1 and 4). Furthermore, as shown in Figure 2, for example, the multiple holes 55 in the first region 52a are arranged radially outward from the circular opening 300, with a regularity in the circumferential spacing relative to the opening 300. The multiple holes 55 in the second region 52b are arranged more uniformly overall, unlike the arrangement in the first region 52a. An example of this uniform arrangement can be explained using Figure 2, where the spacing between each hole 55 has a certain regularity in the vertical and horizontal directions in Figure 2. Due to this difference in the arrangement of the multiple holes 55 in the first and second regions, it is thought that a nearly uniform downflow is generated from the second region, making it easier to stably form a strong airflow region SA circumferentially inside it.

[0023] Furthermore, the second opening ratio of the second region 52b may be set such that the flow velocity of the airflow directed downward from the second region 52b is slower than the flow velocity of the airflow directed downward from the outlet surface 12a of the ULPA filter 12 near the center of the opening 300. In this way, by slowing down the flow velocity of the airflow outside the processing space PS, changes in air velocity above the processing space are further suppressed.

[0024] In Figure 4, the airflow AF in the processing space PS of each processing unit 100a and 100b is indicated by arrows. As shown in Figure 4, an annular strong airflow formation region SA is formed. Such a strong airflow formation region SA functions as an air curtain, and the influence of disturbance factors outside the strong airflow formation region SA, which acts as an air curtain, on the region inside the strong airflow formation region SA (i.e., the processing space PS) can be suppressed. As a result, as shown in Figure 4, changes in wind velocity in the processing space are suppressed, and the airflow AF in the processing space PS becomes constant (generally a straight flow directed downwards).

[0025] Next, the operation and effects of the airflow forming unit 2 (airflow forming device) according to this embodiment will be described.

[0026] The airflow forming unit 2 according to this embodiment is an airflow forming unit that generates an airflow downward from above the coating processing unit 100 toward the processing space PS of the coating processing unit 100. The airflow forming unit 2 includes a gas supply unit 10 that blows the introduced gas downward from a discharge surface 12a facing the processing space PS. The airflow forming unit 2 also includes an airflow control plate 50 that is positioned below the discharge surface 12a and above the processing space PS, surrounding the opening 300 directly above the processing space PS. The airflow control plate 50 forms an annular strong airflow forming region SA around the opening 300 with respect to the gas blown downward from the discharge surface 12a, generating a stronger airflow than the surrounding area.

[0027] In the airflow forming unit 2 according to this embodiment, an annular strong airflow forming region SA is formed around the opening 300 directly above the processing space PS, and this strong airflow forming region SA functions as an air curtain. By distributing the airflow over the cup 101 in this way, even if a disturbance factor occurs outside the strong airflow forming region SA, for example, the area inside the strong airflow forming region SA, i.e., the processing space PS, is suppressed from being affected by the disturbance factor. In other words, in the airflow forming unit 2 according to this embodiment, the change in air velocity in the processing space is suppressed because the strong airflow forming region SA functions as an air curtain. As described above, the airflow forming unit 2 according to this embodiment can suppress the change in air velocity in the processing space, which is a parameter of airflow change, and suppress variations in the film thickness of the substrate W after liquid treatment.

[0028] Figure 5 shows the center air velocity (air velocity at the center of the processing space) for each positive pressure value of the apparatus. In Figure 5, the horizontal axis represents the cups 101 (CUP1, CUP2) of the two processing units 100a and 100b for each positive pressure value of the apparatus (0 Pa, 0.4 Pa, 0.8 Pa, 1.5 Pa, 2.0 Pa). The vertical axis represents the center air velocity. Here, it is conceivable that a change in the positive pressure value of the apparatus changes the airflow in the processing space (i.e., the center air velocity), causing variations in the film thickness of the substrate W. In the comparative example configuration without the airflow control plate 50 according to this embodiment, as shown in Figure 5, the center air velocity fluctuates by a maximum of Fe1 between each positive pressure value of the apparatus. In contrast, in the configuration with the airflow control plate 50 according to this embodiment, as shown in Figure 5, the amount of fluctuation in the center air velocity between each positive pressure value of the apparatus is clearly smaller than the amount of fluctuation Fe1 in the comparative example described above, and the variation in the center air velocity was suppressed.

[0029] Furthermore, by suppressing variations in the center air velocity, variations in the film thickness of the substrate W can be suppressed, as shown in Figure 6. Figure 6 is a diagram showing the substrate film thickness for each positive pressure value of the apparatus. In Figure 6, the horizontal axis represents the radial position of the substrate W, and the vertical axis represents the film thickness of the substrate W. Each graph in Figure 6 shows the film thickness at each radial position of the substrate W at each positive pressure value of the apparatus measured multiple times under different conditions. For example, in the comparative example configuration without the airflow control plate 50 according to this embodiment, as shown in Figure 6, the film thickness at the center of the substrate W varies by a maximum variation amount Fe2 between each positive pressure value of the apparatus. In contrast, in the configuration with the airflow control plate 50 according to this embodiment, as shown in Figure 6, the amount of variation in the film thickness at the center of the substrate W between each positive pressure value of the apparatus is clearly smaller than the variation amount Fe2 in the comparative example described above, and variations in the film thickness of the substrate W can be suppressed.

[0030] The airflow control plate 50 has an annular wall portion 51 that extends vertically to surround the opening 300, and a bottom portion 52 that extends horizontally, continuous with the lower end of the wall portion 51 and facing the discharge surface 12a. The wall portion 51 extends vertically such that a narrow gap 51a is formed between its upper end and the discharge surface 12a. With this configuration, the gas blown downward from the gas supply unit 10 is temporarily stored between the bottom portion 52 and the discharge surface 12a, and the stored gas is then blown out through the narrow gap 51a between the wall portion 51 and the discharge surface 12a. Due to the pressure loss in the narrow gap 51a, the flow velocity of the airflow formed by the blown-out gas increases, and the strong airflow formation region SA described above is formed. This ensures that an annular strong airflow formation region SA is reliably formed around the opening 300.

[0031] As shown in Figure 2, the bottom portion 52 has a plurality of holes 55 that send gas downward. The bottom portion 52 has a first region 52a, which is a region continuous with the lower end of the wall portion 51, and a second region 52b, which is a region outside the first region 52a. The first opening ratio, which is the proportion of the plurality of holes 55 in the first region 52a, may be lower than the second opening ratio, which is the proportion of the plurality of holes 55 in the second region 52b. In this way, by making the opening ratio of the first region 52a closer to the wall portion 51 in the bottom portion 52 lower than the opening ratio of the outer second region 52b, the flow velocity of the airflow formed by the gas blown out from the holes 55 in the first region 52a becomes relatively faster. This makes it possible to reliably form a strong airflow forming region SA in the vicinity of the wall portion 51 (i.e., around the opening 300).

[0032] The airflow forming unit 2 further comprises a plurality of spacers 70, the upper end of which is connected to the outlet surface 12a and the lower end of which is connected to the bottom 52. The plurality of spacers 70 may have the same height in the vertical direction. With this configuration, the separation distance (gap) between the outlet surface 12a and the bottom 52 can be kept constant by the plurality of spacers 70 that are the same height. In this way, by keeping the size of the space where the gas is accumulated constant, it is possible to suppress differential pressure that occurs in different regions (for example, between a plurality of adjacent processing spaces PS) and cause the airflow to fluctuate.

[0033] The spacer 70 may be provided along the wall portion 51. This prevents variations in the size of the narrow gap 51a and further suppresses variations in airflow across the region. In addition, the spacer 70 provided along the wall portion 51 functions as a resistance to the gas flow, and in combination with the resistance function of the narrow gap 51a, it increases the flow velocity of the airflow blown out from the narrow gap 51a, thereby more effectively forming a strong airflow region SA.

[0034] In a plan view, the area of ​​the opening 300 may be narrower than the area of ​​the substrate W placed in the processing space PS. By making the area of ​​the opening 300, which is provided directly above the processing space PS, narrower than the area of ​​the substrate W placed in the processing space PS, an air curtain can be appropriately formed on the area of ​​the substrate W when a strong airflow formation area SA is formed around the opening 300. This makes it possible to more reliably suppress variations in the film thickness of the substrate W after liquid treatment.

[0035] Although this embodiment has been described above, this disclosure is not limited to the above embodiment. For example, although the airflow forming unit 2 has been described as generating an airflow toward the processing space PS of the coating processing unit 100 of the resist coating apparatus 1, it is not limited to this. For example, the airflow forming apparatus may be an apparatus that generates an airflow toward the processing space of other liquid processing units (e.g., developing processing units). [Explanation of Symbols]

[0036] 2...Airflow forming unit (airflow forming device), 10...Gas supply unit, 12a...Blow-out surface (first surface), 50...Airflow control plate (airflow forming unit), 51...Wall section, 51a...Narrow gap, 52...Bottom section, 52a...First region, 52b...Second region, 55...Hole section, 70...Spacer, 100...Coating processing section (liquid processing section), 300...Opening, PS...Processing space, SA...Strong airflow forming region, W...Substrate.

Claims

1. An airflow forming device that generates an airflow from above the liquid processing section toward the processing space of the liquid processing section, A gas supply unit that blows the introduced gas downward from a first surface facing the processing space, The device comprises an airflow forming section positioned below the first surface and above the processing space, surrounding the opening directly above the processing space, and forming an annular strong airflow forming region around the opening where a stronger airflow is generated than in the outer region for the gas blown downward from the first surface, The airflow forming section has an annular wall portion extending vertically to surround the opening, and a bottom portion that is continuous with the lower end of the wall portion and extends horizontally to face the first surface. The wall portion extends in the vertical direction such that a gap is formed between its upper end and the first surface, in the airflow forming device.

2. The bottom portion has multiple holes formed therein to allow gas to be sent downwards. The bottom portion has a first region which is a region continuous with the lower end of the wall portion, and a second region which is a region outside the first region. The airflow forming apparatus according to claim 1, wherein the first opening ratio, which is the proportion occupied by the plurality of holes in the first region, is lower than the second opening ratio, which is the proportion occupied by the plurality of holes in the second region.

3. The system further comprises a plurality of spacers, the upper end of which is connected to the first surface and the lower end of which is connected to the bottom. The airflow forming apparatus according to claim 1 or 2, wherein the plurality of spacers have the same height in the vertical direction.

4. The airflow forming apparatus according to claim 3, wherein the spacer is provided along the wall portion.

5. The airflow forming apparatus according to claim 1, wherein, when viewed from above, the region of the opening is narrower than the region of the substrate placed in the processing space.

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