Coating film forming apparatus, coating film forming method, and storage medium

Abstract

This coating film formation device comprises: a rotating holding unit that holds a substrate and rotates the same; a coating liquid nozzle that forms a ring-shaped coating film along the periphery of the substrate by discharging a coating liquid to a first position on the peripheral edge of the rotating substrate; and a gas nozzle that discharges a gas at a second position which is downstream in the rotational direction of the substrate and which is further towards the rotational center of the substrate than the first position of the rotating substrate, and that is provided in order to form the coating film via the flow of the gas towards the peripheral edge of the substrate from the second position.

Description

[Technical field]

[0001] The present disclosure relates to a coating film forming apparatus, a coating film forming method, and a storage medium. [Background technology]

[0002] In the manufacturing process of semiconductor devices, a coating liquid may be supplied to the peripheral portion of a semiconductor wafer (hereinafter, referred to as a wafer) to form a coating film. Patent Document 1 describes a method of forming a coating film on a rotating wafer by moving a nozzle so that the position where a processing liquid (coating liquid) is supplied moves between the outer periphery and the peripheral portion of the wafer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018-207672 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can prevent the inner peripheral edge of a coating film from protruding when forming a ring-shaped coating film on the peripheral portion of a substrate along the circumference of the substrate. [Means for solving the problem]

[0005] The coating film forming apparatus of the present disclosure includes: a rotating holder that holds and rotates a substrate; a coating liquid nozzle that ejects a coating liquid onto a first position on a peripheral portion of the rotating substrate to form a ring-shaped coating film along a circumference of the substrate; a gas nozzle for discharging gas to a second position on the rotating substrate, the second position being closer to a rotation center of the substrate than the first position and downstream in a rotation direction of the substrate, and for shaping the coating film by a flow of the gas from the second position toward a peripheral edge of the substrate; Equipped with. Effect of the Invention

[0006] ADVANTAGEOUS EFFECTS OF THE DISCLOSURE When forming a ring-shaped coating film on the peripheral portion of a substrate along the circumference of the substrate, the present disclosure can prevent the inner peripheral edge of the coating film from protruding. [Brief description of the drawings]

[0007] [Figure 1] 1 is a vertical sectional side view of a coating film forming apparatus according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional plan view of the coating film forming apparatus. [Diagram 3] 3 is a plan view showing a gas nozzle and a coating liquid nozzle provided in the coating film forming apparatus. FIG. [Figure 4] FIG. 4 is a side view showing the gas nozzle. [Diagram 5] 3 is a plan view showing a gas nozzle and a coating liquid nozzle provided in the coating film forming apparatus. FIG. [Figure 6] 5 is a side view showing the operation of the coating film forming apparatus. FIG. [Figure 7] 5 is a side view showing the operation of the coating film forming apparatus. FIG. [Figure 8] 5 is a side view showing the operation of the coating film forming apparatus. FIG. [Figure 9] FIG. 4 is a vertical cross-sectional side view of the wafer showing the state of the coating film. [Figure 10] FIG. 4 is a vertical cross-sectional side view of the wafer showing the state of the coating film. [Figure 11] FIG. 4 is a vertical cross-sectional side view of the wafer showing the state of the coating film. [Figure 12] FIG. 4 is a vertical cross-sectional side view of the wafer showing the state of the coating film. [Figure 13] FIG. 4 is a plan view showing another configuration example of the coating film forming apparatus. [Figure 14] FIG. 11 is an explanatory diagram showing a process in the other configuration example. [Figure 15] FIG. 4 is a vertical sectional side view showing another configuration example of the gas nozzle. [Figure 16]FIG. 4 is a plan view of the wafer for explaining the positional relationship between the gas nozzle and the wafer. [Figure 17] FIG. 13 is a plan view showing another example of the configuration of a gas nozzle. [Figure 18] FIG. 2 is a vertical cross-sectional side view of the gas nozzle; [Figure 19] FIG. 11 is a graph showing the results of an evaluation test. [Figure 20] FIG. 11 is a graph showing the results of an evaluation test. [Figure 21] FIG. 11 is a graph showing the results of an evaluation test. [Figure 22] FIG. 11 is a graph showing the results of an evaluation test. [Diagram 23] FIG. 11 is a graph showing the results of an evaluation test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A coating film forming apparatus 1 according to an embodiment of the present disclosure will be described with reference to a vertical side view in FIG. 1 and a horizontal plan view in FIG. 2. This coating film forming apparatus 1 rotates a wafer W, which is a circular substrate, and discharges a coating liquid from a nozzle onto the peripheral portion of the surface of the wafer W. The coating liquid flows from the discharged position toward the peripheral edge of the wafer W, forming an annular coating film M along the circumference of the wafer W. As will be described in detail later, when forming the coating film M in this manner, the coating film forming apparatus 1 supplies a gas to the wafer W to prevent the formation of a hump M1, which is a protrusion at the inner peripheral edge of the coating film M. In this example, the diameter of the wafer W is 300 mm, and the gas supplied to the wafer W is air.

[0009] The coating film forming apparatus 1 includes a spin chuck 11, a rotation mechanism 12, pins 13, a lifting mechanism 14, a guide ring 15, and a cup 21. The spin chuck 11, which is a rotation holding unit, holds the wafer W horizontally by vacuum-adsorbing the center of the back surface of the wafer W. The spin chuck 11 is connected to a rotation mechanism 12 including a motor. The rotation mechanism 12 rotates the spin chuck 11 vertically at a rotation speed according to a control signal output from a control unit 10, which will be described later. The wafer W is placed on the spin chuck 11 so that the center P of the wafer W is aligned with the center of rotation of the spin chuck 11 in a plan view, and therefore the center P is also the center of rotation of the wafer W. The rotation direction of the wafer W is clockwise in a plan view.

[0010] Three pins 13 (only two are shown in FIG. 1) for supporting the wafer W are provided so as to surround the spin chuck 11 in a plan view, and can be raised and lowered by a lifting mechanism 14. The pins 13 transfer the wafer W between a transfer mechanism for the wafer W (not shown) and the spin chuck 11. A guide ring 15 having a mountain-shaped cross section is provided below the spin chuck 11, and the outer periphery of the guide ring 15 bends downward and extends. The guide ring 15 serves to guide any liquid that spills from the wafer W to the bottom of a cup 21.

[0011] Next, the cup 21 will be described. The cup 21 is circular and is provided to surround the guide ring 15, the spin chuck 11, and the wafer W placed on the spin chuck 11, and to prevent scattering of the coating liquid. The cup 21 is open at the top so that the wafer W can be transferred. A gap 22 is formed between the side surface of the cup 21 and the outer periphery of the guide ring 15, forming a discharge path for liquid and gas. An upright exhaust pipe 23 is provided below the cup 21, and an exhaust port 24 opens at the upper end of the exhaust pipe 23. The inside of the cup 21 is constantly exhausted through the exhaust port 24 during processing of the wafer W. A drainage port 25 opens at the bottom of the cup 21.

[0012] The coating film forming apparatus 1 also includes a guide 31, a moving mechanism 32, a support 33, a coating liquid nozzle 41, and a gas nozzle 42. The guide 31 is provided on the rear side of the cup 21, extending horizontally to the left and right. The moving mechanism 32 is movable along the extension direction of the guide 31. The support 33 includes an arm 34 extending forward from the moving mechanism 32, and a sub-arm 35 connected to the arm 34, and is raised and lowered by the moving mechanism 32. In the following description, the left and right sides refer to the left and right sides when viewed from the rear toward the front.

[0013] More specifically, the arm 34 and the sub-arm 35 are formed by branching the arm 34 on the way forward, and the sub-arm 35 extends to the left. A coating liquid nozzle 41 and a gas nozzle 42 are provided at the tip of the arm 34 and the tip of the sub-arm 35, respectively. Therefore, the coating liquid nozzle 41 and the gas nozzle 42 are connected to a moving mechanism 32 common to these nozzles 41, 42 via the support 33, and the moving mechanism 32 allows horizontal movement to the left and right and vertical movement.

[0014] The coating liquid nozzle 41 and the gas nozzle 42 are configured to be movable between a standby position, which is outside the cup 21 (i.e., outside the wafer W placed in the cup 21) in a plan view, and a processing position, which is above the peripheral portion of the wafer W. FIG. 2 shows a state in which the coating liquid nozzle 41 and the gas nozzle 42 are positioned at the standby position, and the plan view of FIG. 3 shows a state in which the coating liquid nozzle 41 and the gas nozzle 42 are positioned at the processing position. At the processing position, the coating liquid nozzle 41 and the gas nozzle 42 each eject the coating liquid and the air toward the peripheral portion of the wafer W. The standby position and the processing position for the coating liquid nozzle 41 are a first standby position and a first processing position, respectively, and the standby position and the processing position for the gas nozzle 42 are a second standby position and a second processing position, respectively.

[0015] The coating liquid nozzle 41 is configured as, for example, a cylinder having an outer peripheral wall that narrows toward the tip side, and has a circular discharge port on its tip surface. The coating liquid nozzle 41 is connected to a coating liquid supply unit 41A via piping. The coating liquid supply unit 41A includes a valve, a storage unit in which the coating liquid is stored, a pump, etc., and pressure-feeds the coating liquid from the storage unit toward the coating liquid nozzle 41 and discharges it from the coating liquid nozzle 41.

[0016] The orientation of the coating liquid nozzle 41 will now be described. In order to prevent the coating liquid discharged onto the rotating wafer W from moving toward the center P of the wafer W and to form a coating film M of a desired width, the coating liquid nozzle 41 discharges the coating liquid downward from the center side toward the peripheral edge side of the wafer W. In other words, the coating liquid is discharged in an oblique direction with respect to the vertical and horizontal planes.

[0017] In FIG. 3, the rotation direction of the wafer W is indicated by an arrow. In a plan view, the coating liquid nozzle 41 discharges the coating liquid in a direction following the rotation direction of the wafer W. By discharging the coating liquid in this manner, the coating liquid is prevented from being repelled by the wafer W and scattering, and the uniformity of the thickness of the coating film is increased. The following of the rotation direction will be described in more detail when explaining the gas nozzle 42. In FIG. 3, the area projected onto the wafer W by extending the discharge port of the coating liquid nozzle 41 at the processing position in the discharge direction of the coating liquid is shown as a projection area R1, and the center of the projection area R1 is represented as P1. The projection area R1 corresponds to the first position where the coating liquid is discharged on the wafer W. The discharge direction of the coating liquid from the coating liquid nozzle 41 is also indicated by a chain line D1 in the figure. This chain line is represented as a straight line passing through the center of the discharge port of the coating liquid nozzle 41, and is drawn so as to pass through the center P1 of the projection area R1.

[0018] Here, the hump M1, which is a protrusion of the coating film M, will be described with reference to FIG. 4, which is a vertical cross-sectional side view of the wafer W. Most of the coating liquid discharged toward the projection region R1 flows toward the peripheral edge of the wafer W due to the coating liquid being discharged from the center side toward the peripheral edge side and the centrifugal force of the wafer W. However, some of the coating liquid moves from the projection region R1 to a position near the center P of the wafer W outside the projection region R1 due to the pressure applied when colliding with the wafer W. At the position near the center P, the coating liquid is less likely to be supplied than the area from the projection region R1 to the peripheral edge of the wafer W, and the flow of the coating liquid becomes gentle, so that the drying of the coating liquid proceeds relatively quickly. In this way, the supply and drying of the coating liquid to the position near the center P may occur at the position. From another perspective, it can be said that the drying of the coating liquid proceeds quickly at the hump M1. Since the hump M1 is formed as described above, the hump M1 becomes, for example, a ring shape along the circumference of the wafer W.

[0019] The gas nozzle 42 is configured to eject air so as to form an air flow from the inner peripheral edge of the coating film M toward the outer edge (i.e., the peripheral edge of the wafer W), and to break down the hump M1 before solidification by the wind pressure of the air, and to push the coating liquid constituting the hump M1 toward the outer edge side of the coating film M. In this way, the gas nozzle 42 shapes the coating film M so as to remove the hump M1. In order to reliably obtain this effect, the period during which air is ejected from the gas nozzle 42 is set to overlap with the period during which the coating liquid is ejected from the coating liquid nozzle 41, in order to eject air onto the hump M1 before it loses its fluidity.

[0020] The gas nozzle 42 will be described below. The gas nozzle 42 is configured as a cylinder having an outer peripheral wall that narrows toward the tip side, for example, and a circular discharge port 43 opens at the tip surface of the gas nozzle 42. The gas nozzle 42 is connected to a gas supply unit 42A via a pipe. The gas supply unit 42A includes a valve, a flow rate adjustment mechanism, an air supply source, and the like. The supply of air from the air supply source to the gas nozzle 42 is cut off by opening and closing the valve. The flow rate of the air supplied to the gas nozzle 42 (i.e., the flow rate of the air discharged from the gas nozzle 42) is adjusted to a predetermined flow rate by the flow rate adjustment mechanism. The temperature of the air supplied from the gas supply unit 42A to the gas nozzle 42 in this manner is, for example, 16°C to 24°C.

[0021] The arrangement of the gas nozzle 42 at the processing position will be described below with reference to FIGS. 3 and 4. As described above, the gas nozzle 42 is provided to apply wind pressure to the inner peripheral edge of the coating film M toward the peripheral edge of the wafer W. To ensure that this action is performed, the gas nozzle 42 ejects air downward from the center side of the wafer W toward the peripheral edge side. That is, the air is ejected in an oblique direction relative to the vertical and horizontal planes. In the drawings, the area where the ejection port of the gas nozzle 42 at the processing position is extended in the gas ejection direction and projected onto the wafer W is shown as a projection area R2, and the center of the projection area R2 is represented as P2. The projection area R2 corresponds to a second position on the wafer W where the gas is ejected.

[0022] The gas discharge direction of the gas nozzle 42 is indicated by a dotted line D2 in the figure. This dotted line is shown as a straight line passing through the center of the discharge port 43 of the gas nozzle 42. Therefore, the dotted line is drawn so as to pass through the center P2 of the projection region R2. The angle between the gas discharge direction D2 in a side view and the surface of the wafer W is indicated in FIG. 4 as the side view nozzle angle θ. Note that, since the wafer W is placed on the spin chuck 11 so that its surface is horizontal, the side view nozzle angle θ is also the angle between the horizontal plane and the gas discharge direction D2.

[0023] Assuming that the flow rate of air discharged from the gas nozzle 42 is constant, the smaller the side view nozzle angle θ, the stronger the force pressing the hump M1 toward the peripheral edge of the wafer W. However, if the side view nozzle angle θ is too small, the risk of contact between the gas nozzle 42 and the wafer W increases. From this viewpoint, as described above, the side view nozzle angle θ is preferably 20° or more. Also, as will be described in the evaluation test later, it has been confirmed that the hump M1 could be removed by setting the side view nozzle angle θ to 30° or 60°. Therefore, the side view nozzle angle θ is preferably set to 20° to 60°, and more preferably to 30° to 60°.

[0024] In addition, the distance between the center P2 of the projection area R2 of the gas nozzle 42 and the inner peripheral edge of the coating film M in the air discharge direction in a plan view is defined as the film separation distance L1. The smaller the film separation distance L1, the more preferable it is from the viewpoint of sufficiently increasing the air pressure acting on the coating film M. As will be described in the evaluation test later, the film separation distance L1 is preferably 0 mm or more and less than 5 mm, and more preferably 0 mm to 3 mm. In FIG. 4, the gas nozzle 42 when the processing position is set so that the film separation distance L1 is 0 mm is shown by a solid line, and the gas nozzle 42 when the processing position is set so that the film separation distance L1 is greater than 0 mm is shown by a two-dot chain line.

[0025] The position of the inner peripheral edge of the coating film M on the wafer W may be detected, for example, by performing a test in advance, and the position of the projection region R2 of the gas nozzle 42 may be set based on the position of the inner peripheral edge and the film separation distance L1. Note that, depending on the spread of the coating liquid discharged from the coating liquid nozzle 41 to the projection region R1, for example, the inner peripheral edge of the coating film M may be located slightly closer to the center P of the wafer W than the projection region R1 (see FIG. 3). In that case, when the position of the center P1 of the projection region R1 in the radial direction of the wafer W is compared with the position of the center P2 of the projection region R2, the projection region R2 will be located closer to the center P of the wafer W, even if the film separation distance L1 is 0 mm, for example.

[0026] Next, the positional relationship between the projection area R1 and the projection area R2 in the rotational direction of the wafer W will be described. As shown in FIG. 3, the projection area R2 is located downstream of the projection area R1 in the rotational direction. To supplement the downstream side of the rotational direction, when viewed in the rotational direction of the wafer W, two arcuate regions along the rotational direction are located between the projection areas R1 and R2, and the downstream side of the rotational direction is the shorter arcuate region of the two arcuate regions. To be more specific, as shown in FIG. 3, when viewed in the rotational direction of the wafer W with the projection area R1 as the base point, the projection area R2 is downstream in the rotational direction, and when viewed in the rotational direction of the wafer W with the projection area R2 as the base point, the projection area R1 is downstream in the rotational direction. Thus, the positional relationship between the projection areas R1 and R2 differs depending on the base point, but the length of the above-mentioned arcuate region between the projection areas R1 and R2 is compared, and the projection area R1 is taken as the base point based on the comparison result.

[0027] As described above, drying proceeds relatively quickly in the hump M1. If the drying proceeds and the hump M1 solidifies, it will be impossible to break down and remove the hump M1 by wind pressure. In other words, in order to remove the hump M1, it is required that the hump M1 to which air is supplied is immediately after being discharged onto the wafer W and is made of a coating liquid having sufficient fluidity. Therefore, the projection region R2 is positioned downstream of the projection region R1 in the rotation direction.

[0028] In order to obtain the effect of the air more reliably, it is preferable that the distance between the projection regions R1 and R2 is shorter. However, the air discharged to the projection region R2 diffuses the surface of the wafer W due to the impact of the collision with the projection region R2. If the distance between the projection regions R1 and R2 is too small, the liquid flow of the coating liquid discharged from the coating liquid nozzle 41 may be fanned by the air dispersing the surface of the wafer W, and the uniformity of the film thickness of the coating film M may decrease. Therefore, from the viewpoint of obtaining a high pressing effect of the coating film M by the air while more reliably suppressing the disturbance of the liquid flow of the coating liquid, it is preferable that the separation distance L2 between the projection regions R1 and R2 in the rotation direction of the wafer W is an appropriate value, specifically, for example, 30 mm to 100 mm.

[0029] The distance L2 between the projection areas R1 and R2 in the rotation direction described above will be supplemented. As shown in FIG. 3, a virtual straight line L3 is drawn from the center P of the wafer W through the center P2 of the projection area R2 toward the peripheral edge of the wafer W. Meanwhile, a virtual circle C1 is set with the center P of the wafer W as its center and passing through the center P1 of the projection area R1, and the intersection point between this circle C1 and the straight line L3 is P0. The length of the arc between the center P1 of the projection area R1 and the intersection point P0 of the circle C1 is the distance L2. As described above, the positions of the coating liquid nozzle 41 and the gas nozzle 42 in the rotation direction of the wafer W are different, but for convenience of illustration, FIG. 1 shows these nozzles as being at the same position in the rotation direction and aligned along the radial direction of the wafer W.

[0030] The following description will be continued with reference to the plan view of the wafer W in FIG. 5. In plan view, the gas discharge direction D2 from the gas nozzle 42 is set to be a direction following the rotation direction of the wafer W, that is, a direction that does not go against the rotation of the wafer W. To add to the fact that the direction follows the rotation direction, the center P2 of the projection region R2 into which the air is discharged moves in a uniform circular motion due to the rotation of the wafer W. When the angle θ3 between the velocity vector V1 with the center P2 as the base point and the gas discharge direction D2 in plan view is an obtuse angle, the gas is discharged following the rotation direction of the wafer W (see FIG. 5). By having the discharge direction D2 follow the rotation direction of the wafer W in this way, it is possible to prevent the air discharged into the projection region R2 from being repelled by the rotation of the wafer W and scattering around, thereby preventing the liquid flow that is supplied to the wafer W and flows toward the peripheral edge of the wafer W from being disturbed, and therefore the uniformity of the film thickness of the coating film M can be improved.

[0031] Now, a virtual circle C2 is set that passes through the center P2 of the projection area R2 of the gas nozzle 42 and has its center at the center P of the wafer W. This circle C2 is a locus that the center P2 of the projection area R2 describes due to the rotation of the wafer W. A tangent line T2 is drawn at P2 to this circle C2. When the gas nozzle 42 is disposed so that the gas discharge direction D2 follows the rotation direction as described above, if the angle formed by the tangent line T2 and the gas discharge direction D2 in a plan view is taken as a planar gas discharge angle θ2, the planar gas discharge angle θ2 is, for example, 30° to 90°.

[0032] Also, a tangent line T1 is drawn at a circle C1 passing through a center P1 of the projection region R1 of the coating liquid nozzle 41 described above. The angle between the tangent line T1 and the coating liquid discharge direction D1 in a planar view is defined as a planar liquid discharge angle θ1. In this example, the planar liquid discharge angle θ1 and the planar gas discharge angle θ2 are the same, for example, both are 60°. Note that the coating liquid discharge direction D1 and the gas discharge direction D2 in a planar view can be made parallel to each other. By making the discharge directions D1 and D2 parallel in this way, the gas flow from the gas nozzle 42 is prevented from approaching the liquid flow from the coating liquid nozzle 41, and the disturbance of the liquid flow can be more reliably suppressed, which is preferable.

[0033] Moreover, the height distance between the bottom end of the gas nozzle 42 and the surface of the wafer W is designated as a nozzle height distance H (see FIG. 4). If the nozzle height distance H is too large, the air pressure acting on the hump M1 decreases, whereas if it is too small, there is a risk of the gas nozzle 42 coming into contact with the wafer W. From this perspective and in view of the results of an evaluation test described below, the nozzle height distance H is preferably set to, for example, less than 10 mm, and more preferably set to 3 mm to 5 mm.

[0034] From the viewpoint of sufficiently increasing the pressure of the air acting on the hump M1 and from the results of evaluation tests described later, it is preferable that the flow rate of the air discharged from the gas nozzle 42 is greater than 10 L / min, for example, 20 L / min or more. From the viewpoint of sufficiently increasing the pressure of the air acting on the hump M1 and preventing the pressure loss from becoming too large due to the discharge port 43 being too small, the aperture (diameter of the discharge port 43) L0 of the discharge port 43 is set to, for example, 0.5 mm to 2 mm.

[0035] As shown in FIG. 1, the coating film forming apparatus 1 includes a control unit 10. The control unit 10 is configured by a computer and includes a program. The program includes a set of steps so that a series of operations in the coating film forming apparatus 1, which will be described later, can be performed. The program causes the control unit 10 to output control signals to each part of the coating film forming apparatus 1, and the operation of each part is controlled. Specifically, the control signals control the rotation speed of the spin chuck 11 by the rotation mechanism 12, the elevation of the pin 13 by the elevation mechanism 14, the supply of the coating liquid to the coating liquid nozzle 41 by the coating liquid supply unit 41A, the supply of air to the gas nozzle 42 by the gas supply unit 42A, and the movement of each nozzle by the movement mechanism 32. The program is stored in a storage medium, such as a compact disc, a hard disk, or a DVD, and installed in the control unit 10.

[0036] Next, the processing operation of the coating film forming apparatus 1 on the wafer W will be described with reference to Figs. 6 to 8, which show the sides of the wafer W, the coating liquid nozzle 41, and the gas nozzle 42. As in Fig. 1, Figs. 6 to 8 also show the coating liquid nozzle 41 and the gas nozzle 42 as being aligned along the radial direction of the wafer W at the same positions in the rotation direction of the wafer W. Also, changes in the state of the coating film M that are presumed to occur on the surface of the wafer W during processing of the wafer W will be described with reference to Figs. 9 to 12. Figs. 9 to 12 show vertical cross sections of the coating film M in the radial direction of the wafer W, and in Figs. 10 and 11, portions of the surface of the coating film M where drying has progressed relatively significantly are indicated by thick lines.

[0037] First, while the coating liquid nozzle 41 and the gas nozzle 42 are waiting at the waiting positions outside the cup 21, the wafer W is transported onto the cup 21 by a transport mechanism (not shown). The wafer W is placed on and held on the spin chuck 11 via the pins 13. The wafer W then rotates at a rotation speed lower than 250 rpm, specifically, for example, 100 rpm. Next, when the coating liquid nozzle 41 and the gas nozzle 42 are moved to their respective processing positions by the moving mechanism 32, the gas nozzle 42 starts discharging air, and an airflow is formed at the peripheral portion of the surface of the wafer W toward the peripheral edge of the wafer W (FIG. 6).

[0038] By rotating the wafer W at least once, for example, multiple times, from the start of the air discharge, air is supplied to the entire peripheral portion of the wafer W, and the temperature at each portion of the peripheral portion becomes uniform. Next, the coating liquid is discharged from the coating liquid nozzle 41 to the projection region R1 of the wafer W described above (FIG. 9). This coating liquid flows toward the peripheral edge of the wafer W due to the centrifugal force caused by the rotation of the wafer W and the force of the discharge from the coating liquid nozzle 41, forming a coating film M (FIG. 7), and a hump M1 is formed at the inner peripheral edge of this coating film M. The liquid flow of the coating liquid discharged from the coating liquid nozzle 41 is indicated as 40 in each figure. As described above, the coating liquid is difficult to move toward the center P of the wafer W, and therefore, for the hump M1, the flow of the coating liquid is difficult to occur on the side surface toward the center P of the wafer W (i.e., the inner peripheral end surface of the coating film M), and drying proceeds relatively quickly (FIG. 10).

[0039] As the wafer W rotates, the hump M1 moves to the vicinity of the position where the air is being discharged (near the projection area R2 described above), and the hump M1 is exposed to the air flow, and wind pressure acts on the hump M1 toward the peripheral edge of the wafer W. This wind pressure causes the side of the hump M1, where drying has progressed, to crack vertically, and the upper side of the hump M1 moves so as to shift toward the peripheral edge of the wafer W relative to the lower side. The upper side of the hump M1 that moves toward the peripheral edge of the wafer W moves so as to sink downward from its original height, because the fluidity of the coating film M is guaranteed when the air is discharged (FIG. 11).

[0040] As described above, the hump M1 is broken down by the wind pressure so that it is separated into upper and lower parts, and each part forms a protrusion at a different position in the radial direction of the wafer W, but these protrusions are smaller in height than the original hump M1. Therefore, the height of the coating film M in the radial direction is uniformed.

[0041] The region of the coating film M where the height in the radial direction is thus leveled moves away from the position where air is ejected as the wafer W rotates, and drying and solidification progresses in each part of that region (FIG. 12). As the wafer W continues to rotate and the coating liquid and air are ejected onto the wafer W, the formation of the coating film M described above and the removal of the hump M1 that occurs with the formation of the coating film M (specifically, the collapse of the hump M1) are carried out in parallel at different positions in the rotation direction of the wafer W.

[0042] Then, as the wafer W rotates once from the start of the coating liquid discharge, the coating liquid is supplied over the entire circumference of the wafer W, and a ring-shaped coating film M covering the entire peripheral portion of the wafer W is formed, and the discharge of the coating liquid from the coating liquid nozzle 41 stops (FIG. 8). When the area of ​​the wafer W that was located in the projection area R1 when the discharge of the coating liquid was stopped moves to the vicinity of the projection area R2 and is subjected to the action of air, that is, after the removal of the hump M1 is completed over the entire circumference of the wafer W, the discharge of air from the gas nozzle 42 stops. When the drying of the coating film M progresses and the desired film thickness is reached, the rotation of the wafer W stops. Thereafter, the wafer W is transferred to a transfer mechanism (not shown) in a reverse operation to the transfer to the spin chuck 11, and is carried out from the coating film forming device 1.

[0043] In this way, the coating film forming apparatus 1 suppresses the formation of the hump M1, so that the uniformity of the height in the radial direction of the coating film M can be increased. Therefore, it is possible to suppress the occurrence of problems in processing the wafer W in a post-process after the formation of the coating film M, which is caused by the formation of the hump M1. As a result, it is possible to prevent a decrease in the yield of semiconductor products manufactured from the wafer W.

[0044] The above-mentioned problems in the post-process will be explained by giving a specific example. There is no particular limitation on the type of coating film M, but in explaining this specific example, it is assumed to be a film formed on a wafer W on which an underlayer film and a resist film with a pattern are formed in order upward. More specifically, no resist film is formed on the peripheral portion of the wafer W, and the coating film M is formed to cover the underlayer film at the peripheral portion and surround the resist film. The coating film M plays the role of a protective film that prevents etching of the peripheral portion of the underlayer film when the underlayer film is dry-etched along the pattern of the resist film to transfer the pattern to the underlayer film.

[0045] Assume that the coating film M is also etched together with the underlayer film, and the etching process conditions are set so that the coating film M is completely removed at the end of the etching. However, if a hump M1 is formed, it is possible that the hump M1 will become a residue on the underlayer film after etching. In other words, since the thickness of the coating film M at the portion forming the hump M1 is larger than that of other portions, it is possible that the hump M1 will not be completely removed by etching and will remain. It is possible that the residue of the coating film M will become particles and adhere to the pattern formed on the underlayer film, resulting in the aforementioned decrease in yield. However, the coating film forming apparatus 1 can form the coating film M so that the hump M1 is not formed, and therefore it is possible to prevent the decrease in yield caused by the residue.

[0046] In the above processing example, the gas nozzle 42 starts supplying air to the wafer W before the coating liquid nozzle 41 starts discharging the coating liquid, so that the temperature of each part of the peripheral part of the wafer W is uniform. Therefore, after the coating liquid is supplied, the coating liquid dries uniformly at each part of the peripheral part, which is preferable because it suppresses the variation in film thickness. In addition, as described above, the rotation speed of the wafer W is set to a rotation speed lower than 250 rpm when discharging the coating liquid and air to the wafer W because, as described in the evaluation test later, if the rotation speed of the wafer W is too high, the drying of the hump M1 proceeds quickly. In other words, such a rotation speed is preferable because it can suppress the drying of the hump M1 and remove the hump M1 with high reliability.

[0047] In the above processing example, the coating liquid is applied to the peripheral edge of the wafer W only once, i.e., the coating liquid is not applied repeatedly. However, the coating liquid may be applied repeatedly, and even in this case, the hump M1 can be removed.

[0048] Next, the coating film forming apparatus 5, which is a modified example of the coating film forming apparatus 1, will be described with reference to FIG. 13, focusing on the differences from the coating film forming apparatus 1. In the coating film forming apparatus 5, the support 33 on which the coating liquid nozzle 41 is provided does not have the sub-arm 35 and the gas nozzle 42, and the support 33 is composed only of the arm 34. In the coating film forming apparatus 5, a guide 51, a moving mechanism 52, and an arm 54, each of which is configured similarly to the guide 31, the moving mechanism 32, and the arm 34, are provided, and the gas nozzle 42 is provided at the tip of the arm 54, and the moving mechanism 52 allows the gas nozzle 42 to move horizontally in the left-right direction and to move up and down. Therefore, in the coating film forming apparatus 5, the coating liquid nozzle 41 and the gas nozzle 42 are connected to different moving mechanisms 32 and 52, respectively, and can move independently of each other. In this coating film forming apparatus 5, the moving mechanism 32 corresponds to the first moving mechanism, and the moving mechanism 52 corresponds to the second moving mechanism, respectively.

[0049] An example of processing the wafer W by this coating film forming apparatus 5 will be described with reference to FIG. 14. In this processing example, the coating liquid nozzle 41 also discharges the coating liquid at a position other than the position described as the processing position in the coating film forming apparatus 1. First, air is discharged from the gas nozzle 42 at the processing position onto the rotating wafer W, as in the coating film forming apparatus 1. Then, the coating liquid nozzle 41 starts discharging the coating liquid. However, the position of the coating liquid nozzle 41 at the start of discharging is a position horizontally away from the processing position described above, as shown by a solid line in FIG. 14, and the coating liquid is discharged outside the wafer W. The processing position is indicated by a dashed line in the figure.

[0050] Then, the coating liquid nozzle 41, which has discharged the coating liquid, is moved horizontally toward the processing position. With this movement, the projection area R1 of the coating liquid nozzle 41 onto the wafer W moves from the peripheral edge of the wafer W toward the center P of the wafer W along the radial direction of the wafer W. Then, when the coating liquid nozzle 41 moves to the processing position, the coating liquid nozzle 41 is stopped, and when the coating film R is formed on the entire circumference of the wafer W, the discharge of the coating liquid is stopped. When forming a film by the coating liquid nozzle 41 as described above, the gas nozzle 42 may be kept stationary during the discharge of the coating liquid, or may include a period in which the gas nozzle 42 moves.

[0051] Even in the case of a device configuration in which the coating liquid nozzle 41 is movable independently of the gas nozzle 42 as in this coating film forming device 5, the processing may be performed so that the coating liquid nozzle 41 remains stationary at the processing position during the discharge of the coating liquid as described in Figures 6 to 8. In that case, however, it is advantageous to use the configuration of the coating film forming device 1 in terms of the simplicity of the device configuration.

[0052] The gas nozzle is not limited to the configuration having a circular discharge port 43 like the gas nozzle 42. FIG. 15 shows an example in which a gas nozzle 61 is provided instead of the gas nozzle 42 in the coating film forming apparatus 1. The gas nozzle 61 is formed in a square block shape, and an air flow path 62 is formed therein from above to below. The flow path 62 is formed obliquely from the center P side of the wafer W toward the peripheral edge side in the gas nozzle 61 at the processing position. A lower end surface 63 of the gas nozzle 61 faces the wafer W, and a discharge port 64 forming the downstream end of the flow path 62 is opened in the lower end surface 63. The discharge port 64 is an arc-shaped slit in a plan view.

[0053] Hereinafter, the positional relationship between the gas nozzle 61 arranged at the processing position and the coating film M formed on the wafer W will be described with reference to FIG. 16, which is a plan view of the wafer W. Since the discharge port 64 is arc-shaped, the projection area R3 of the discharge port 64 on the wafer W in the air discharge direction is also arc-shaped. The arc of the projection area R3 is along the inner circumferential edge of the coating film M as shown in FIG. 16. That is, the discharge port 64 is formed so as to be along the inner circumferential edge. By forming the discharge port 64 in this way, the area in the wafer W where the hump M1 can be pressed by air becomes relatively large, so that the hump M1 can be removed with high reliability.

[0054] In Fig. 16, the width center P3 of the projection region R3 is indicated by a dotted line. Although the film separation distance L1 has been described with reference to Fig. 3 and Fig. 4, when the discharge port 64 is formed along the inner peripheral edge of the coating film M as shown in Fig. 16, the distance in the air discharge direction in a plan view between each portion in the length direction of the width center P3 of the projection region R3 and the coating film M may be the distance described as the film separation distance L1.

[0055] FIG. 17 shows an example in which the discharge port 64 is a straight slit instead of a curved shape along the inner peripheral edge of the coating film M. When the discharge port 64 is formed in this way, the distance between the inner peripheral edge of the coating film M in the air discharge direction in a plan view differs for each part in the length direction of the width center P3 of the projection region R3. When the distance between each part of the width center P3 and the inner peripheral edge of the coating film M differs in this way, it is preferable that a part of each part falls within the range described as the film separation distance L1, since sufficient wind pressure can be applied to the hump M1. It is more preferable that the entire length direction of the width center P3 falls within the range described as the film separation distance L1, since wind pressure can be applied to the hump M1 more reliably.

[0056] The discharge port 64 may be a curved slit that does not follow the inner circumferential edge of the coating film M. In this case, the positional relationship between the inner circumferential edge of the coating film M and the width center P3 of the projection region R3 is similar to the positional relationship between the inner circumferential edge of the coating film M and the width center P3 of the projection region R3 when the discharge port 64 is a linear slit as shown in Fig. 17. In other words, it is preferable that at least a part of the width center P3 falls within the range described as the film separation distance L1.

[0057] Incidentally, although each gas nozzle has been described as having a configuration for discharging air from the center side toward the peripheral edge side of the wafer W, air may be discharged vertically downward. That is, the nozzle angle θ in a side view shown in FIG. 4 may be 90°. Since the inside of the cup 21 is evacuated during processing of the wafer W, the air discharged vertically flows over the surface of the wafer W toward the outer periphery of the wafer W. Therefore, the wind pressure of this air can be applied to the hump M1 as described above. However, in order to obtain the effect of the air more reliably, it is preferable that the gas nozzle is configured to discharge air from the center side toward the peripheral edge side of the wafer W.

[0058] In the above-described embodiment, the period during which the coating liquid is discharged onto the wafer W overlaps with the period during which air is discharged onto the wafer W. However, since air needs to be supplied while the hump M1 is fluid, depending on the properties of the coating liquid used, the discharge of air may be started after the discharge of the coating liquid is completed. In other words, the discharge period of the coating liquid and the discharge period of the air may not overlap. However, in order to more reliably remove the hump M1, it is preferable to make these discharge periods overlap, and it is more preferable to make the timing of the start of gas discharge earlier than the timing of the start of the discharge of the coating liquid after overlapping the discharge periods in this way.

[0059] The gas to be discharged onto the wafer W is not limited to air, and an inert gas such as nitrogen gas may be used. A heater or a cooling mechanism may be provided in the gas supply unit 42A, and a gas having a higher or lower temperature than room temperature may be supplied to the gas nozzle 42.

[0060] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, modified, and combined in various forms without departing from the scope and spirit of the appended claims.

[0061] [Evaluation test] Next, evaluation tests related to this technology will be described. Evaluation test 1 In the evaluation tests 1-1 to 1-5, a coating film M was formed on a wafer W. For this process, a test device having the same configuration as the coating film forming device 1 was used. Therefore, the gas nozzle 42 described above was used as the gas nozzle. Then, for the wafer W on which the coating film was formed, the thickness of the coating film M at each position along the radial direction was measured using a stylus-type step gauge. To describe this measurement in more detail, the tip (lower end) of a needle that can move up and down was brought into contact with the surface of the wafer W. Then, the needle was moved along the radial direction of the wafer W toward the peripheral edge of the wafer W. The film thickness was measured by detecting the up and down movement of the needle during this radial movement. The evaluation tests 1-1 to 1-5 differ in the combination of the number of rotations of the wafer W during the ejection of the coating liquid and air, the flow rate of the air ejected from the gas nozzle 42, and the timing of starting the ejection of air.

[0062] In evaluation test 1-1, the rotation speed of the wafer W was set to 100 rpm, and the coating liquid and air were discharged onto the wafer W for processing. The air discharge started several seconds after the coating film M was formed on the entire circumference of the wafer W. The flow rate of the discharged air was set to 40 L / min. This flow rate corresponds to a wind speed of 7 m / sec.

[0063] In the evaluation test 1-2, the rotation speed of the wafer W was set to 100 rpm, and the coating liquid and air were discharged onto the wafer W for processing. The start of the air discharge was earlier than the start of the coating liquid discharge, as in the embodiment. The flow rate of the air discharged from the gas nozzle 42 was 40 L / min, the same as in the evaluation test 1-1.

[0064] In the evaluation test 1-3, the air flow rate was set to 30 L / min. This flow rate corresponds to a wind speed of 10 m / sec. In the evaluation test 1-4, the air flow rate was set to 20 L / min. This flow rate corresponds to a wind speed of 7 m / sec. Except for the different air flow rates, the evaluation tests 1-3 and 1-4 were performed under the same processing conditions as the evaluation test 1-2. In the evaluation test 1-5, the rotation speed of the wafer W was set to 250 rpm, and the processing was performed in the same manner as the evaluation test 1-3. In the evaluation tests 1-1 to 1-5, the film separation distance L1 described in FIG. 3 and FIG. 4 was set to 0 mm.

[0065] FIG. 18 is a graph showing the results of evaluation test 1. In the graph of FIG. 18, the results of evaluation tests 1-1, 1-2, 1-3, 1-4, and 1-5 are shown by a thin solid line, a dotted line, a dashed line, a two-dot dashed line, and a thick solid line, respectively. The horizontal axis of the graph indicates a distance (unit: mm) from a position at a predetermined distance away from the center P of the wafer W to the peripheral edge of the wafer W along the radial direction of the wafer W, which is set to 0 mm. Hereinafter, the distance is expressed as a radial position. The vertical axis of the graph indicates the height (unit: μm) of the surface of the wafer W on which the coating film M is not formed, which is set to 0 mm. Since the horizontal and vertical axes of the graph are set in this way, the waveform of the graph indicates the shape of the coating film M along the radial direction of the wafer W. In addition, for the graphs of each figure described from Figure 19 onwards, which are shown in the tests from Evaluation Test 2 onwards, the vertical and horizontal axes are set in the same manner as the vertical and horizontal axes of the graph in Figure 18 for Evaluation Test 1, so that the shape of the coating film M is represented by a waveform.

[0066] In the waveform of the graph of Evaluation Test 1-1, a relatively large peak of about 3 μm is shown at a radial position of about 0.5 mm, and it was confirmed that the hump M1 could not be removed. In Evaluation Tests 1-2 to 1-5, a first peak and a second peak are seen within a radial position range of 0.5 mm to slightly larger than 0.5 mm. The second peak is a peak that appears closer to the peripheral edge of the wafer W than the first peak. These peaks in each step are considered to indicate the protrusion of the film caused by the collapse of the hump M1 as described in FIG. 11. The first peak and the second peak in each of Evaluation Tests 1-2 to 1-5 are smaller than the peak of the waveform in Evaluation Test 1-1, being 1.3 μm or less. Therefore, it was confirmed that the hump M1 could be removed by discharging air in Evaluation Tests 1-2 to 1-5.

[0067] Moreover, from the results of the evaluation tests 1-1 to 1-5, it is found that it is necessary to eject air onto the coating film M before the drying progresses in order to remove the hump M1. Therefore, it is preferable to start ejecting air onto the wafer W before ejecting the coating liquid shown as the embodiment in order to increase the reliability of removing the hump M1.

[0068] In addition, when the results of evaluation tests 1-2 to 1-4 are compared with the results of evaluation test 1-5, the first peak is smaller in evaluation tests 1-2 to 1-4 in which the rotation speed is 100 rpm than in evaluation test 1-5 in which the rotation speed is 250 rpm. This is because, as described in the embodiment, the rotation speed of the wafer W is relatively low in evaluation tests 1-2 to 1-4, which suppresses drying of the inner peripheral edge of the coating film M, and therefore the effect of the air pressure is greater. Therefore, from the above test results, as described in the embodiment, it is preferable to set the rotation speed of the wafer W to be lower than 250 rpm, and more preferably to be 100 rpm or less.

[0069] When the results of evaluation tests 1-2 to 1-4 are compared, the second peak is smaller in the order of evaluation tests 1-4, 1-3, and 1-2. In other words, the second peak is smaller as the air flow rate is higher. Therefore, it is preferable to set the air flow rate to 20 mL / min or more, and it is more preferable to set the flow rate to a higher value within that range.

[0070] Evaluation test 2 As in Evaluation Test 1, a test device was used to form a coating film M on a wafer W, and the thickness of the coating film M was measured. In Evaluation Test 2, the coating film M was formed by setting the film separation distance L1 described in FIG. 4 and the like to a different value for each wafer W. In Evaluation Tests 2-1, 2-2, and 2-3, the film separation distance L1 was set to 0 mm, 3 mm, and 5 mm, respectively. In these Evaluation Tests 2-1 to 2-3, the nozzle height distance H described in FIG. 4 was 5 mm, and the nozzle angle θ in a side view was 60°.

[0071] The results of evaluation tests 2-1, 2-2, and 2-3 are shown in the graph of FIG. 19 by the dashed line, dotted line, and solid line, respectively. In evaluation test 2-3, a relatively large peak of about 3 μm was observed at a radial position of about 0.5 mm, but such a large peak was not observed in evaluation tests 2-1 and 2-2. Therefore, it was confirmed that the hump M1 could not be removed in evaluation test 2-3, but the hump M1 could be removed in evaluation tests 2-1 and 2-2. From the results of this evaluation test 2, it can be seen that the membrane separation distance L1 is preferably set to a value smaller than 5 mm, and more preferably set to 0 mm to 3 mm.

[0072] Evaluation Test 3 As in Evaluation Test 1, a test device was used to form a coating film M on a wafer W, and the thickness of the coating film M was measured. In Evaluation Test 3, the nozzle height distance H was set to a different value for each wafer W, and the coating film M was formed. In Evaluation Tests 3-1, 3-2, and 3-3, the nozzle height distance H was set to 3 mm, 5 mm, and 10 mm, respectively. In these Evaluation Tests 3-1 to 3-3, the film separation distance L1 was set to 0 mm, and the nozzle angle θ in a side view was set to 60°.

[0073] The results of the evaluation tests 3-1, 3-2, and 3-3 are shown in the graph of FIG. 20 by the dashed line, dotted line, and solid line, respectively. As is clear from the waveform of the graph, in the evaluation test 3-3, a first peak and a second peak were observed at a radial position of about 0.5 mm, and the second peak was relatively large, being 1.5 μm or more. However, such a large peak was not confirmed in the evaluation tests 3-1 and 3-2. Therefore, it is considered that the hump M1 collapsed in the evaluation tests 3-1 and 3-2 as described in FIG. 11, and it was confirmed that the height of the protrusion of the film caused by the collapse was also suppressed. Thus, from the results of the evaluation test 3, it can be seen that the nozzle height distance H is preferably set to a value smaller than 10 mm, and more preferably set to 3 mm to 5 mm.

[0074] Evaluation Test 4 As in Evaluation Test 1, a test device was used to form a coating film M on a wafer W, and the thickness of the coating film M was measured. In Evaluation Test 4, the side view nozzle angle θ was set to a different value for each wafer W, and the coating film M was formed. In Evaluation Tests 4-1 and 4-2, the side view nozzle angle θ was set to 60° and 30°, respectively. In these Evaluation Tests 4-1 to 4-2, the above-mentioned film separation distance L1 was 0 mm, and the nozzle height distance H was 3 mm.

[0075] The results of evaluation tests 4-1 and 4-2 are shown by the solid line and dotted line, respectively, in the graph of Figure 21. As is clear from the waveform of the graph, in both evaluation tests 4-1 and 4-2, the presence of the hump M1 was not observed and it is considered that it was removed. Thus, from the results of evaluation test 4, it was shown that when the nozzle angle θ in side view is set to 30° to 60°, it is preferable because the hump M1 can be removed.

[0076] Evaluation Test 5 As in Evaluation Test 1, a test device was used to form a coating film M on a wafer W, and the thickness of the coating film M was measured. In Evaluation Test 5, the temperature of the air supplied to the gas nozzle 42 was set to a different value for each wafer W, and the coating film M was formed. In Evaluation Tests 5-1, 5-2, and 5-3, the temperature was set to 24°C, 20°C, and 16°C, respectively. Note that 24°C is the same as the room temperature in which the tests were performed. In these Evaluation Tests 5-1 to 5-3, the film separation distance L1 was set to 0 mm, the nozzle height distance H was set to 3 mm, and the flow rate of the discharged air was set to 20 L / min.

[0077] The results of evaluation tests 5-1, 5-2, and 5-3 are shown by the dashed line, dotted line, and solid line in the graph of Figure 22. As is clear from the waveforms of the graph, the presence of the hump M1 was not observed in any of evaluation tests 5-1 to 5-3, and it is considered that the hump M1 was removed. Therefore, it was shown that the effect of the air temperature on the removability of the hump M1 is small in the range of 16°C to 24°C, and that the said 16°C to 24°C is a preferable temperature for the air to be used.

[0078] Evaluation Test 6 As in Evaluation Test 1, a test device was used to form a coating film M on a wafer W, and the thickness of the coating film M was measured. In Evaluation Test 6, the flow rate of the discharged air was set to a different value for each wafer W, and the coating film M was formed. In Evaluation Tests 6-1, 6-2, and 6-3, the flow rate was set to 30 mL / min, 20 mL / min, and 10 mL / min, respectively. In these Evaluation Tests 6-1 to 6-3, the film separation distance L1 was set to 0 mm, the nozzle height distance H was set to 3 mm, and the temperature of the discharged air was set to 16°C.

[0079] The results of the evaluation tests 6-1, 6-2, and 6-3 are shown in the graph of FIG. 23 by solid lines, dotted lines, and chain lines, respectively. As is clear from the waveforms of the graphs, in the evaluation test 6-3, the first and second peaks were observed at a radial position of about 0.5 mm, and the height of the second peak was relatively large at 1 μm or more. However, in the evaluation tests 6-1 and 6-2, such a large peak was not observed, and the height of the peak was 0.5 μm or less. Therefore, in the evaluation tests 3-1 and 3-2, it is considered that the hump M1 collapsed as described in FIG. 11, and it was confirmed that the height of the protrusion of the membrane caused by the collapse was also suppressed. Thus, from the results of the evaluation test 6, it can be seen that the flow rate of the discharged air is preferably greater than 10 L / min, and more preferably 20 L / min. [Explanation of symbols]

[0080] W wafer R1 projection area R2 projection area 41 Coating fluid nozzle 42 Gas nozzle

Claims

1. a rotation holder that holds and rotates the substrate; a coating liquid nozzle that ejects a coating liquid onto a first position on a peripheral portion of the rotating substrate to form an annular coating film along a circumference of the substrate; a gas nozzle for discharging gas to a second position on the rotating substrate, the second position being closer to a rotation center of the substrate than the first position and downstream in a rotation direction of the substrate, and for shaping the coating film by a flow of the gas from the second position toward a peripheral edge of the substrate; A coating film forming apparatus comprising:

2. The coating liquid nozzle is moved between a first processing position above the substrate where the coating liquid is discharged to the first position, and a first standby position outside the substrate in a plan view, and The coating film forming apparatus of claim 1, further comprising a moving mechanism for moving the gas nozzle between a second processing position above the substrate where the coating liquid is ejected to the second position, and a second waiting position outside the substrate in a planar view.

3. 3. The coating film forming apparatus according to claim 2, wherein the moving mechanism is a common moving mechanism for the coating liquid nozzle and the gas nozzle.

4. The moving mechanism includes a first moving mechanism that moves the coating liquid nozzle; The coating film forming apparatus according to claim 2 , further comprising: a second moving mechanism that moves the gas nozzle independently of the coating liquid nozzle.

5. 3. The coating film forming apparatus according to claim 2, wherein the height of said gas nozzle from the surface of said substrate when said gas is discharged is 1 mm to 5 mm.

6. The coating film forming apparatus according to claim 1 , wherein the gas nozzle ejects the gas toward the second position from a center side toward a peripheral edge side of the substrate.

7. 7. The coating film forming apparatus according to claim 6, wherein an angle between the surface of the substrate and a direction in which gas is ejected from the gas nozzle is 60[deg.] or less in a side view.

8. The coating film forming apparatus according to claim 1 , wherein the gas nozzle ejects the gas in a direction following a rotation direction of the substrate in a plan view.

9. 9. The coating film forming apparatus according to claim 8, wherein an angle between a tangent drawn to a circle formed by a locus of the center of the second position due to rotation of the substrate in a planar view and a gas ejection direction of the gas nozzle is 30° to 90°.

10. 2. The coating film forming apparatus according to claim 1, wherein the distance between the first position and the second position in the rotation direction of the substrate is 30 mm to 100 mm.

11. 2. The coating film forming apparatus according to claim 1, wherein the distance between the center of the second position and the inner circumferential edge of the coating film in a plan view in the gas ejection direction is 0 mm to 3 mm.

12. 2. The coating film forming apparatus according to claim 1, wherein a period during which the coating liquid is discharged from the coating liquid nozzle to the first position and a period during which the gas is discharged from the gas nozzle to the second position overlap with each other.

13. The coating film forming apparatus according to claim 12 , wherein the gas is discharged from the gas nozzle to the second position before the coating liquid is discharged from the coating liquid nozzle to the first position.

14. 2. The coating film forming apparatus according to claim 1, wherein the gas nozzle has a discharge port having a diameter of 0.5 mm to 2 mm.

15. holding and rotating the substrate by a rotary holder; A step of discharging a coating liquid from a coating liquid nozzle onto a first position on a peripheral edge of the rotating substrate to form a ring-shaped coating film along a circumference of the substrate; discharging gas from a gas nozzle to a second position on the rotating substrate, the second position being closer to a rotation center of the substrate than the first position and downstream in a rotation direction of the substrate; shaping the coating film by the gas flow from the second position toward the peripheral edge of the substrate; The coating film forming method includes the steps of:

16. A storage medium for storing a computer program used in a coating film forming apparatus, 16. A storage medium, wherein the computer program includes a group of steps for executing the coating film forming method according to claim 15.

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