TWI652120B - Coating method - Google Patents

Abstract

A coating method is to form a spiral liquid chemical film CF before forming a liquid pool PD of a chemical liquid on a circular substrate W. The liquid medicine of the liquid pool PD is well fused with the spiral liquid chemical film CF. For this reason, when the circular substrate W is rotated to expand the liquid medicine of the liquid pool PD to cover the spiral medical liquid film CF, the liquid medicine of the liquid pool PD is favorably expanded. Further, when the liquid medicine of the liquid pool PD is expanded, the unevenness of the surface of the spiral chemical liquid film CF can be made flat. By this, it is possible to prevent a film breakage or the like, and it is possible to make the film thickness uniform when a highly viscous liquid chemical film CF is formed on the circular substrate W.

Description

Coating method

The present invention relates to a coating method for applying a high-viscosity chemical liquid to a substrate such as a semiconductor substrate, a glass substrate for a liquid crystal display, a glass substrate for a photomask, or a substrate for a disk.

The coating device includes: a holding rotating portion for holding the circular substrate and rotating the circular substrate; and a nozzle for discharging the liquid medicine from the substrate held by the holding rotating portion to the circular substrate (for example) Refer to Patent Documents 1 and 2). The coating device forms a chemical liquid film by a method called spin coating. First, the circular substrate is rotated at a low speed. Next, the drug solution is spit out from the nozzle. Then, after the discharge of the chemical liquid is stopped, the circular substrate is rotated at a high speed so that the chemical liquid on the circular substrate can have a desired film thickness. In Patent Documents 1 and 2, when the chemical liquid is discharged from the nozzle, the nozzle is moved so as to traverse the center of rotation of the circular substrate.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. SHO 60-217627.

Patent Document 2: Japanese Patent No. 3970695.

However, such conventional examples have the following problems. That is, even if spin coating is performed using a highly viscous chemical solution, there is a problem that the chemical solution cannot be uniformly expanded, or the chemical liquid is bulged at the center of the circular substrate, or the chemical solution cannot be well expanded. For example, a pattern such as an integrated circuit is formed on the surface (main surface) of the circular substrate, whereby the surface of the circular substrate has irregularities.

A high-viscosity chemical liquid of, for example, 300 cP (centipoise; centipoise) or more is discharged onto the surface of the uneven surface of the circular substrate, and spin coating is performed at a high speed rotation of, for example, 1000 rpm or more. In this case, by the unevenness, a film (uncoated) which is not loaded with the chemical liquid film CF as indicated by a symbol M in (a) of FIG. 16 or a (b) as shown in FIG. 16 is generated. As indicated by the symbol N, the unevenness is reflected. Thereby, the film thickness uniformity is locally deteriorated.

The present invention has been developed in view of such circumstances, and an object thereof is to provide a coating method capable of making a film thickness uniform when a high-viscosity chemical liquid is formed on a circular substrate.

The present invention has the following constitution in order to achieve such an object. That is, the coating method of the present invention supplies a high-viscosity chemical solution of 300 cP or more to a circular substrate and forms a chemical liquid film on the circular substrate; the coating The method includes the steps of: rotating the circular substrate at a first rotation speed, and moving the chemical liquid nozzle from the chemical liquid nozzle while moving the chemical liquid nozzle located above the circular substrate toward a radial direction of the circular substrate Discharging onto the circular substrate to form a spiral drug solution; after forming the spiral drug solution film, the drug solution is discharged from the drug solution nozzle to the center of the circular substrate, thereby a central portion of the circular substrate forms a liquid pool of the chemical liquid; and after the liquid pool forming the chemical liquid, the circular substrate is rotated at a second rotation speed faster than the first rotation speed, thereby expanding the liquid The liquid of the pool covers the spiral liquid film.

According to the coating method of the present invention, a spiral liquid chemical film is formed before the liquid pool of the chemical liquid is formed on the circular substrate. The liquid solution of the liquid pool will be well combined with the spiral liquid film. For this reason, when the circular substrate is rotated to expand the liquid medicine of the liquid pool to cover the spiral liquid chemical film, the liquid medicine of the liquid pool is well expanded. Further, when the liquid medicine in the liquid pool is expanded, the unevenness of the surface of the spiral chemical liquid film can be made flat. By this, it is possible to prevent breakage or the like, and it is possible to make the film thickness uniform when a highly viscous liquid chemical film is formed on a circular substrate.

Further, after the liquid pool is formed in the center portion of the circular substrate, when the spiral liquid chemical film is formed, the liquid medicine in the liquid pool is dried. In this case, when the circular substrate is rotated at the second rotation speed (high speed), the liquid pool does not spread well, and the chemical liquid film is raised closer to the center portion than the peripheral portion of the circular substrate. However, since the liquid pool is formed after the formation of the spiral liquid film, The liquid pool can be well extended so as not to dry the liquid medicine of the liquid pool. Further, since the chemical solution can be spread well, no excess chemical solution is discharged for the purpose of expansion. For this reason, the liquid medicine can be saved.

Further, in the above-described coating method, it is preferable that the chemical liquid nozzle is formed from a peripheral portion of the circular substrate toward a central portion of the circular substrate along the circular substrate when the spiral chemical liquid film is formed Move in the radial direction. After forming the spiral medical liquid film, the medical liquid nozzle is located above the central portion of the circular substrate. For this reason, the liquid medicine nozzle can directly perform the action of forming the liquid pool. That is, the liquid pool of the chemical liquid can be formed efficiently.

Further, preferably, the coating method further includes the step of rotating the circular substrate at the first rotation speed and from above a peripheral portion of the circular substrate while stopping the movement of the chemical liquid nozzle The chemical liquid nozzle discharges the chemical solution onto the circular substrate, thereby forming a ring-shaped chemical liquid film along the peripheral edge portion of the circular substrate.

When the chemical liquid film is formed in a spiral shape in the vicinity of the peripheral portion of the circular substrate, a region where the chemical liquid film is not formed occurs. However, since the chemical liquid film is formed in a ring shape along the peripheral edge portion of the circular substrate, the region where the chemical liquid film is not formed can be eliminated. Therefore, in the vicinity of the peripheral portion of the circular substrate, it is possible to prevent film breakage and the like, and it is possible to make the film thickness uniform when a highly viscous liquid chemical film is formed on the circular substrate. Further, when the boundary between the inside and the outside of the peripheral portion of the circular substrate is traversed, for example, the liquid column of the chemical liquid discharged from the liquid medicine nozzle becomes After being unstable, there is a fear that the spiral liquid film cannot be formed well. However, this problem can be prevented.

Further, the coating method described above preferably further includes a step of performing a prewet treatment, which means rotating the circular substrate before ejecting the chemical solution from the liquid chemical nozzle, and from the solvent nozzle The solvent is discharged onto the circular substrate, whereby a solvent film is formed on the circular substrate. When a spiral liquid chemical film is to be formed without pre-wetting treatment, the discharged chemical liquid is agglomerated near the discharge port of the chemical liquid nozzle, and in some cases, it is difficult to adhere the chemical liquid to the circular substrate. However, the chemical solution can be easily attached to the circular substrate by the pre-wetting treatment. Further, the chemical liquid easily flows in a portion where the solvent film on the substrate exists.

Moreover, in the above-described coating method, one example of the pre-wetting treatment is a state in which the solvent has entered the concave portion formed in the circular substrate. Since the solvent has entered the concave portion, it is easy to perform replacement with the chemical liquid. For this reason, it is possible to prevent insufficient filling of the chemical liquid to the concave portion.

Further, in the above coating method, it is preferable that the chemical liquid film of each of the spiral chemical liquid films does not have a gap with the chemical liquid film of the adjacent ring in the radial direction. When there is a gap between the chemical liquid film of each ring and the chemical liquid film of the adjacent ring, even if the circular substrate is rotated at the second rotation speed (high speed), the liquid medicine in the expansion liquid pool still flows away from the gap or the concave portion. . For this reason, the liquid medicine of the liquid pool can be well expanded by not generating the gap.

Further, in the above-described coating method, it is preferable that the chemical liquid nozzle is located closer to a center portion of the circular substrate than a position on a peripheral portion side of the circular substrate when the spiral chemical liquid film is formed. At the time, the clearance between the front end surface of the chemical liquid nozzle and the surface of the circular substrate is formed to be larger than the aforementioned clearance in the position on the peripheral edge side. At a position closer to the peripheral portion side than the position on the central portion side of the circular substrate, the relative rotational speed with respect to the circular substrate of the chemical liquid nozzle is increased. For this reason, when the chemical liquid is immersed in the circular substrate, the action of the force applied to the direction of rotation of the chemical liquid becomes large, and the liquid breakage which is broken due to the breakage of the chemical liquid is likely to occur. When the chemical liquid nozzle is located on the peripheral portion side, the liquid leakage can be prevented by reducing the clearance. Further, when the chemical liquid nozzle is located at the center portion, a liquid pool of the chemical liquid is formed. It is possible to suppress the adhesion of the chemical solution to the liquid medicine nozzle by increasing the clearance.

Further, in the above-described coating method, it is preferable that the chemical liquid nozzle is located closer to a center portion of the circular substrate than a position on a peripheral portion side of the circular substrate when the spiral chemical liquid film is formed. At this time, the rotation speed of the circular substrate is formed to be faster than the aforementioned rotation speed when the peripheral portion side is located. At a position closer to the peripheral portion side than the position on the central portion side of the circular substrate, the relative rotational speed of the circular substrate with respect to the chemical liquid nozzle is increased. For this reason, when the chemical liquid is immersed in the circular substrate, the action of the force applied to the direction of rotation of the chemical liquid becomes large, and the liquid breakage which is broken due to the breakage of the chemical liquid is likely to occur. When the liquid medicine nozzle is located on the side of the peripheral portion, the rotation speed of the circular substrate is slowed down. Thereby, it is possible to prevent the liquid medicine discharged from the chemical liquid nozzle from being broken. Further, when the chemical liquid nozzle is located on the center side, the rotation speed of the circular substrate is accelerated. This prevents excessive liquid medicine from being discharged.

According to the coating method of the present invention, a spiral liquid chemical film is formed before the liquid pool of the chemical liquid is formed on the circular substrate. The liquid solution of the liquid pool will be well combined with the spiral liquid film. For this reason, when the circular substrate is rotated to expand the liquid medicine of the liquid pool to cover the spiral liquid chemical film, the liquid medicine of the liquid pool is well expanded. Further, when the liquid medicine in the liquid pool is expanded, the unevenness of the surface of the spiral chemical liquid film can be made flat. By this, it is possible to prevent breakage or the like, and it is possible to make the film thickness uniform when a highly viscous liquid chemical film is formed on a circular substrate.

1‧‧‧ Coating device

2‧‧‧ Keeping the rotating part

3‧‧‧Solvent nozzle

4‧‧‧Drug nozzle

4a‧‧‧Exporting

4b‧‧‧Internal flow path

4c‧‧‧ front face

7‧‧‧Rotating chuck

8, 29‧‧‧ Rotary Drive Department

9‧‧‧ cup body

10‧‧‧Standby container

13‧‧‧ solvent supply source

15‧‧‧Solvent piping

17‧‧‧Drug supply source

19‧‧‧Pharmaceutical piping

21‧‧‧Solvent nozzle moving mechanism

23‧‧‧Drug liquid nozzle moving mechanism

25, 31‧‧ mechanical arm

27‧‧‧Axis

33‧‧‧Up and down moving department

35‧‧‧ Planar Moving Department

37‧‧‧Control Department

39‧‧‧Operation Department

AX1, AX2‧‧‧ rotating shaft

CF‧‧‧ liquid film

CL‧‧‧ clearance

CT‧‧‧ Central Department

E‧‧‧The Peripheral Department

H‧‧‧ recess

M‧‧‧Fracture

N‧‧‧ concave

P1, P2‧‧‧ pump

PD‧‧‧ liquid pool

SF‧‧‧ solvent film

V1, V2‧‧‧ opening and closing valve

W‧‧‧Circular substrate

Fig. 1 is a schematic configuration diagram of a coating apparatus of an embodiment.

Fig. 2 (a) is a longitudinal sectional view of the chemical liquid nozzle, and (b) is a schematic view showing the shape of the discharge port of the chemical liquid nozzle observed from A of (a).

Fig. 3 is a plan view showing a solvent nozzle moving mechanism and a chemical liquid nozzle moving mechanism.

Figure 4 is a flow chart showing the coating apparatus.

(a) to (c) of Fig. 5 are side views for explaining the pre-wetting treatment of the embodiment.

Fig. 6 is a side view for explaining the formation of a chemical liquid film.

(a) and (b) in Fig. 7 are used to illustrate the formation of a ring-shaped liquid film. view.

Fig. 8 is a plan view for explaining the formation of a spiral medical liquid film.

Fig. 9 is a plan view showing a region of a coating range on a circular substrate.

Fig. 10 is a schematic view showing coating conditions of respective regions.

Figure 11 is a side view for explaining the clearance between the front end surface of the liquid chemical nozzle and the surface of the circular substrate.

(a) and (b) of Fig. 12 are side views for explaining the formation of a chemical liquid film of a ring shape and a spiral shape.

Figure 13 is a side view for explaining the formation of a liquid pool of a chemical liquid.

Fig. 14 (a) is a schematic view showing a state in which the liquid medicine of the liquid pool is expanded by high-speed rotation, and (b) is a schematic view showing a chemical liquid film after high-speed rotation.

Fig. 15 is a view showing the insufficient filling of the chemical liquid to the concave portion.

Fig. 16 (a) is a schematic view showing a broken film, and (b) is a schematic view showing a state in which irregularities are reflected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a coating apparatus of an embodiment. Fig. 2 (a) is a longitudinal sectional view of a chemical liquid nozzle. (b) of Fig. 2 is a schematic view showing the shape of the discharge port of the liquid chemical nozzle viewed from A of Fig. 2(a). Fig. 3 is a plan view showing a solvent nozzle moving mechanism and a chemical liquid nozzle moving mechanism.

<Configuration of Coating Device 1>

Refer to Figure 1. The coating device 1 includes a holding rotating unit 2, a solvent nozzle 3, and a chemical liquid nozzle 4.

The holding rotating unit 2 holds a circular substrate (hereinafter referred to as "substrate") W in a substantially horizontal posture and rotates it. The holding rotary unit 2 includes a spin chuck 7 and a rotation driving unit 8. The rotary chuck 7 is designed to be rotatable about the rotation axis AX1 and hold the substrate W. The spin chuck 7 is configured to hold the substrate W by, for example, vacuum-adsorbing the back surface of the substrate W. The rotation drive unit 8 performs driving for rotating the rotary chuck 7 about the rotation axis AX1. The rotary drive unit 8 is constituted by, for example, an electric motor. Further, the rotation axis AX1 substantially coincides with the center portion CT of the substrate W.

The solvent nozzle 3 is for discharging the solvent onto the substrate W held by the holding rotating portion 2. As the solvent, for example, a thinner or a PGMEA (Propylene Glycol Monomethyl Ether Acetate; propylene glycol methyl ether acetate) can be used. By discharging the solvent onto the substrate W and performing pre-wetting treatment, the chemical solution discharged from the chemical liquid nozzle 4 is easily attached to the substrate W. Moreover, it is easy to spread the chemical solution on the substrate W. However, the liquid medicine cannot be well extended by only the solvent.

The chemical liquid nozzle 4 is for discharging the chemical liquid onto the substrate W held by the holding rotary unit 2. As the high viscosity liquid chemical system, a resin such as polyimide can be used. The resin is used as a protective film of the substrate W on which the pattern is formed or an interlayer insulating film between the substrates W. Viscosity of liquid It is 300 cP or more and 10000 cP or less. As shown in (a) of FIG. 2 and (b) of FIG. 2, the discharge port 4a of the chemical liquid nozzle 4 has a rectangular shape. When the discharge port 4a of the chemical liquid nozzle 4 has a rectangular shape, the area to be coated by one rotation can be increased as compared with the case where the discharge port 4a is circular or square. Further, by this, it is possible to shorten the discharge time and the coating operation in which the liquid column is kept in a stable state with low rotation.

In (a) of FIG. 2, reference numeral 4b denotes an internal flow path (internal flow path 4b) of the chemical liquid nozzle 4, and is connected in communication with a chemical liquid pipe 19 to be described later. Reference numeral 4c is a front end surface (front end surface 4c) of the chemical liquid nozzle 4. Further, in order to increase the area to be applied by one rotation, when the length of the rectangular discharge port 4a in the longitudinal direction is excessively lengthened (for example, the length of the radius), the liquid described later cannot be formed well in the center portion CT. The case of the pool PD.

Moreover, as shown in FIG. 1, the coating apparatus 1 is equipped with the cup 9 and the standby pot 10. The cup 9 is for surrounding the substrate W and holding the side of the rotating portion 2. The cup body 9 is configured to be moved in the vertical direction by a driving unit (not shown). On the other hand, the standby container 10 is for waiting for the unused chemical liquid nozzle 4. The standby container 10 may be provided with a solvent storage tank for immersing the front end portion of the chemical liquid nozzle 4 in a solvent, and may cover the end portion of the chemical liquid nozzle 4 with a solvent atmosphere. Further, a standby container that allows the solvent nozzle 3 to stand by may be provided.

Further, the coating device 1 includes a solvent supply source 13 and a solvent pipe 15, Pump P1 and open and close valve V1. The solvent supply source 13 is composed of, for example, a bottle. The solvent from the solvent supply source 13 is supplied to the solvent nozzle 3 through the solvent pipe 15. The solvent pipe 15 is provided with a pump P1, an opening and closing valve V1, and the like. The pump P1 sends the solvent to the solvent nozzle 3, and the opening and closing valve V1 supplies and stops the solvent.

Further, the coating device 1 includes a chemical liquid supply source 17, a chemical liquid pipe 19, a pump P2, and an opening and closing valve V2. The chemical supply source 17 is composed of, for example, a bottle. The chemical liquid from the chemical liquid supply source 17 is supplied to the chemical liquid nozzle 4 through the chemical liquid pipe 19. The chemical liquid pipe 19 is provided with a pump P2, an opening and closing valve V2, and the like. The pump P2 sends the chemical solution to the chemical liquid nozzle 4, and the opening and closing valve V2 supplies and stops the chemical liquid.

Moreover, the coating apparatus 1 is provided with the solvent nozzle moving mechanism 21 and the chemical liquid nozzle moving mechanism 23 (refer FIG. 3).

The solvent nozzle moving mechanism 21 rotates (moves) the solvent nozzle 3 around the rotation axis AX2. The solvent nozzle moving mechanism 21 includes a robot arm 25, a shaft 27, and a rotation driving unit 29. The robot arm 25 supports the solvent nozzle 3, and the shaft 27 supports the robot arm 25. That is, the solvent nozzle 3 is connected to one end of the rod-shaped robot arm 25, and the shaft 27 is connected to the other end of the robot arm 25. The rotation drive unit 29 rotates the shaft 27 about the rotation axis AX2, thereby rotating the solvent nozzle 3 and the robot arm 25 about the rotation axis AX2. The rotation drive unit 29 is constituted by an electric motor or the like.

On the other hand, the chemical liquid nozzle moving mechanism 23 moves the chemical liquid nozzle 4 in the vertical direction (Z direction) and in a predetermined first direction (X direction) along the surface of the substrate W. The chemical liquid nozzle moving mechanism 23 includes a mechanical arm 31, a vertical moving portion 33, and a planar moving portion 35. The robot arm 31 supports the chemical liquid nozzle 4. The vertical movement unit 33 moves the chemical liquid nozzle 4 and the mechanical arm 31 in the vertical direction. The plane moving unit 35 moves the chemical liquid nozzle 4, the robot arm 31, and the vertical movement unit 33 in the first direction (X direction). Further, the chemical liquid nozzle 4 is disposed such that the longitudinal direction of the discharge port 4a coincides with the first direction (X direction).

The vertical movement portion 33 and the planar movement portion 35 are constituted by, for example, an electric motor, a screw shaft, a guide rail, or the like. Further, the planar moving portion 35 may be configured to move the chemical liquid nozzle 4 or the like not only in the first direction but also in the second direction (Y direction) orthogonal to the first direction.

Further, the solvent nozzle moving mechanism 21 can move the solvent nozzle 33 in the vertical direction (Z direction) as in the chemical liquid nozzle moving mechanism 23, and can cause the solvent nozzle 3 to face at least one of the first direction and the second direction. mobile. On the other hand, the chemical liquid nozzle moving mechanism 23 is similar to the solvent nozzle moving mechanism 21, and the chemical liquid nozzle 4 can be rotated around the rotating shaft disposed on the side of the cup 9. Further, the solvent nozzle moving mechanism 21 and the chemical liquid nozzle moving mechanism 23 may be multi-joint robot arms.

The coating device 1 shown in FIG. 1 includes a control unit 37 and an operation unit 39. The control unit 37 is configured by a central processing unit (CPU: Central Processing Unit) or the like. The control unit 37 controls each configuration of the coating device 1. Furthermore, the control unit 37 may be composed of a plurality of components. The operation unit 39 includes a display unit, a storage unit, an input unit, and the like. The display unit is constituted by, for example, a liquid crystal monitor. The memory unit is configured by, for example, at least one of a ROM (Read-Only Memory), a RAM (Random-Access Memory), and a hard disk. The input unit is composed of at least one of a keyboard, a mouse, and various buttons. In the memory unit, various conditions of the coating process and an operation program required for the control of the coating device 1 are stored.

<Action of Coating Device 1>

Next, the operation of the coating device 1 will be described with reference to a flow chart (flowchart) shown in FIG. First, in FIG. 1, a conveyance mechanism (not shown) conveys the board|substrate W to the holding rotation part 2. The rotating chuck 7 holding the rotating portion 2 vacuum-adsorbs the back surface of the substrate W to hold the substrate W.

[Step S01: Pre-wet treatment]

The control unit 37 performs a pre-wet treatment in which the substrate W is rotated and the solvent is discharged from the solvent nozzle 3 onto the substrate W before the chemical liquid is discharged from the chemical liquid nozzle 4, whereby the solvent has entered the formation. The process of forming the solvent film SF on the surface of the substrate W other than the recess H in the state of substantially all the recesses H (see (a) in FIG. 5) on the surface of the substrate W. The recess H is, for example, a contact hole, a via, a space, or a trench.

As shown in FIG. 5( a ), the solvent nozzle moving mechanism 21 shown in FIG. 3 moves the solvent nozzle 3 from the standby position on the side of the holding rotary unit 2 toward the upper side of the center portion CT of the substrate W. After the movement, as shown in FIG. 5(b), while the substrate W is rotated at a number of revolutions of several tens of rpm, the solvent is discharged from the solvent nozzle 3 to the substantially central portion CT of the substrate W (the opening and closing valve V1 is opened ( ON)). As shown in an enlarged view surrounded by a broken line in FIG. 5(b), the solvent is discharged until substantially all of the concave portions H formed on the surface of the substrate W are filled with the solvent. The operating conditions in which the recess H is filled with the solvent are set in advance by experiments or the like.

After the recess H is filled with the solvent, the solvent is stopped from being discharged from the solvent nozzle 3 (the opening and closing valve V1 is turned OFF). Further, after the solvent discharge is stopped, the solvent nozzle moving mechanism 21 moves the solvent nozzle 3 from the upper side of the center portion CT of the substrate W toward the standby position outside the substrate W. After the solvent discharge is stopped, the number of revolutions of the substrate W is raised, and the substrate W is rotated at a number of revolutions of several hundred rpm to discharge excess solvent on the substrate W toward the outside of the substrate W (see (c) of FIG. 5). Thereafter, the rotation of the substrate W is stopped. At this time, as shown in the enlarged view of FIG. 6, the concave portion H is in a state in which the solvent has entered, that is, a state in which the solvent (solvent film SF) remains. Further, a solvent film SF is formed on the surface of the substrate W other than the concave portion H.

[Step S02: Formation of a ring-shaped chemical liquid film along the peripheral portion (first circle)]

The control unit 37 rotates the substrate W at the first rotation speed, and discharges the chemical liquid onto the substrate W from the chemical liquid nozzle 4 located above the peripheral edge portion E of the substrate W while the movement of the chemical liquid nozzle 4 is stopped. Thereby, the annular chemical liquid film CF is formed along the peripheral edge portion E of the substrate W.

The chemical liquid nozzle moving mechanism 21 moves the chemical liquid nozzle 4 from the standby container 10 (standby position) outside the substrate W toward the upper side of the peripheral edge portion E of the substrate W (see FIG. 6). The movement of the chemical liquid nozzle 4 is performed by the solvent in the step S01 being discharged from the solvent nozzle 3, and is waited in advance of the substrate W. After the pre-wetting treatment in step S01, the chemical liquid nozzle 4 is lowered, and the clearance CL between the front end surface 4c of the chemical liquid nozzle 4 and the surface of the substrate W is set to 1.0 mm or less (for example, 0.5 mm). Further, when the clearance CL becomes high, the chemical liquid is discharged from the chemical liquid nozzle 4 when the substrate W is rotated, so that the liquid column of the chemical liquid formed between the chemical liquid nozzle 4 and the surface of the substrate W does not become It is stable, and there is a fear of "breaking liquid" that has been broken due to the broken liquid column.

As shown in (a) of FIG. 7, the first ring forms a ring-shaped chemical liquid film CF along the peripheral edge portion (edge portion) E of the substrate W. The substrate W is rotated once at the first rotation speed of several tens of rpm, and the chemical liquid nozzle 4 is stopped without moving toward the radial direction of the substrate W. In this state, the chemical liquid is discharged from the chemical liquid nozzle 4 located above the peripheral edge portion E of the substrate W. Thereby, a ring-shaped chemical liquid film CF is formed along the peripheral edge portion E of the substrate W. Arrow G of (b) in Fig. 7 As shown in the figure, when the chemical liquid film CF is formed in a spiral shape in the vicinity of the peripheral portion E of the substrate W, a region where the chemical liquid film CF is not formed occurs. However, since the chemical liquid film CF is formed in a ring shape along the peripheral edge portion E of the substrate W, the region where the chemical liquid film CF is not formed can be eliminated (see the arrow G). Therefore, in the vicinity of the peripheral portion E of the substrate W, it is possible to prevent film breakage and the like, and finally, when the high-viscosity chemical liquid film CF is formed on the substrate W, the film thickness is made uniform.

Further, the following elimination method can be considered for the region of the arrow G of FIG. 7 (b) in which the chemical liquid film CF is not formed. This method is a method of forming the chemical liquid film CF on the peripheral edge portion E of the substrate W while moving the chemical liquid nozzle 4 toward the upper side of the substrate W while discharging the chemical liquid from the chemical liquid nozzle 4 outside the substrate W. However, in this method, for example, when the boundary between the inside and the outside of the peripheral portion E of the substrate W is traversed, for example, the liquid column of the chemical liquid discharged from the chemical liquid nozzle 4 becomes unstable, and thereafter, it may not be good. The ground forms a spiral of the chemical liquid film CF. Further, there is a fear that the chemical liquid adheres to the side surface of the substrate W and causes contamination or the like. Moreover, when discharging to the outside of the substrate W, the chemical liquid is wasted. However, since the chemical liquid film CF is formed in a ring shape along the peripheral edge portion E, such problems can be prevented.

The first number of rotations of the substrate W in the step S02 to the step S04 is set such that the chemical liquid does not overflow from the peripheral portion E of the substrate W. Also, the first rotational speed is variable.

[Step S03: Formation of a spiral liquid film (after the second lap)]

In the first cycle of step S02, the chemical liquid nozzle 4 is stopped without moving, and the chemical liquid film CF is formed along the peripheral edge portion E. After the second lap, the chemical liquid nozzle 4 is moved to form the chemical liquid film CF into a spiral shape. In other words, the control unit 37 rotates the substrate W at the first rotation speed, and moves the chemical liquid nozzle 4 located above the substrate W from the peripheral edge portion E of the substrate W toward the central portion CT of the substrate W along the radial direction of the substrate W. . While doing this, the chemical liquid is discharged from the chemical liquid nozzle 4 onto the substrate W. Thereby, a spiral drug solution CF is formed (see FIG. 8). Further, the solid line of the spiral of Fig. 8 shows the trajectory of the liquid chemical nozzle 4 of this step. A dot chain line of Fig. 8 shows the trajectory of the liquid medicine nozzle 4 of step S02.

The formation of the chemical solution film CF in steps S02 and S03 can also be performed by partitioning the coating range and under the following conditions. In other words, when the chemical liquid nozzle 4 is moved from the peripheral edge portion E of the substrate W to the central portion CT, for example, the clearance CL between the front end surface 4c of the chemical liquid nozzle 4 and the surface of the substrate W, and the liquid chemical nozzle 4 are used. The movement speed and the rotation speed of the substrate W are changed, and the discharge of the chemical liquid is performed. Thereby, the chemical liquid can be efficiently spread over the unevenness of the concave portion H or the like.

Fig. 9 is a plan view showing a region of a coating range on the substrate W. The region is determined based on the position of the chemical liquid nozzle 4 from the central portion CT of the substrate W, and can be divided into the first region Z1 to the fifth region Z5 and the sixth region (core) Z6 from the peripheral portion E side of the substrate W. . Furthermore, in the aspect of the figure, Figure 9 The first zone Z1 to the sixth zone Z6 show a rough range. Fig. 10 is a schematic view showing coating conditions of the respective first to sixth zones Z1 to Z6. The item "nozzle moving distance" of Fig. 10 shows the distance (mm) from the center portion CT of the substrate W. The substrate W is assumed to use a substrate having a diameter of 300 mm. For example, the distance from the center portion CT of the substrate W of the first zone Z1 is 143 mm, and the movement of the chemical liquid nozzle 4 is not performed. That is, the first zone Z1 shows the formation of the annular liquid chemical film CF of the step S02.

First, the clearance CL between the front end surface 4c of the chemical liquid nozzle 4 and the substrate W will be described with reference to FIG. When the spiral and annular chemical liquid film CF is formed, it is assumed that the chemical liquid nozzle 4 is located closer to the center portion CT side of the substrate W than the position (for example, symbol PS1) on the peripheral portion E side of the substrate W (for example, symbol PS2). when. In this case, the clearance CL is formed to be larger than the clearance CL in the position (symbol PS1) on the side of the peripheral portion E. In other words, the closer the chemical liquid nozzle 4 is to the side of the center portion CT than the peripheral portion E of the substrate W, the larger the clearance CL is.

The clearance CL is set to, for example, 0.5 mm in the peripheral portion E (the first region Z1 and the second region Z2) of the substrate W. Together with the movement of the liquid medicine nozzle 4, that is, each of the first zone Z1 to the sixth zone Z6 where the chemical liquid nozzle 4 is located, the clearance CL is gradually increased. The clearance CL is set to, for example, 3.0 mm in the center portion CT (sixth region Z6) of the substrate W.

At a position closer to the peripheral edge portion E than the position on the CT portion of the center portion of the substrate W, the relative rotational speed with respect to the substrate W of the chemical liquid nozzle 4 is increased. For this reason, when the chemical liquid is immersed in the substrate W, the force applied to the direction of rotation of the chemical liquid becomes large, and the liquid breakage which is broken by the chemical liquid is likely to occur. When the chemical liquid nozzle 4 is located on the side of the peripheral portion E, the liquid leakage can be prevented by reducing the clearance CL. Further, when the chemical liquid nozzle 4 is located at the center portion CT, the liquid pool PD of the chemical liquid is formed. It is possible to suppress the adhesion of the chemical solution to the chemical liquid nozzle 4 by increasing the clearance CL.

Next, the rotation speed (first rotation speed) of the substrate W will be described. When the spiral and annular chemical liquid film CF is formed, it is assumed that the chemical liquid nozzle 4 is located closer to the center portion CT side of the substrate W than the position on the peripheral edge portion E side of the substrate W (for example, the symbol PS1 of FIG. 11) (for example) When the symbol of Figure 11 is PS2). In this case, the rotational speed of the substrate W with respect to the chemical liquid nozzle 4 is formed to be faster than the rotational speed at the side of the peripheral portion E (symbol PS1). In other words, the more the chemical liquid nozzle 4 is located closer to the center portion CT than the peripheral portion E of the substrate W, the faster the rotation speed is increased.

The peripheral speed portion E (the first zone Z1 and the second zone Z2) of the substrate W is set to, for example, 13 rpm. The rotation speed is increased together with the movement of the liquid medicine nozzle 4. The center portion CT (sixth region Z6) of the substrate W sets the number of revolutions to, for example, 40 rpm.

At a position closer to the peripheral edge portion E than the position on the CT portion of the center portion of the substrate W, the relative rotational speed with respect to the substrate W of the chemical liquid nozzle 4 is increased. For this reason, when the chemical liquid is immersed in the substrate W, the force applied to the direction of rotation of the chemical liquid becomes large, and the liquid breakage which is broken by the chemical liquid is likely to occur. When the chemical liquid nozzle 4 is located on the side of the peripheral portion E, the number of revolutions of the substrate W can be slowed down. Thereby, it is possible to prevent the liquid medicine discharged from the chemical liquid nozzle 4 from being broken. Further, when the chemical liquid nozzle 4 is located at the center portion CT, the number of revolutions of the substrate W is increased. This prevents excessive discharge of the drug solution.

Further, the discharge speed of the chemical liquid (discharge rate, unit: ml/s) is the lowest flow rate with which the liquid is not broken (can be subjected to liquid breaking) with respect to the rotational speed of the substrate W. By using such a discharge speed, the liquid medicine can be saved more.

Next, the moving speed of the chemical liquid nozzle 4 will be described. As shown in FIG. 9, since the application range on the peripheral edge portion E side of the substrate W is wide, the discharge time of the chemical liquid becomes long. On the other hand, since the coating range on the CT side of the center portion is narrow, the discharge time of the chemical liquid is shortened. Then, when the spiral chemical liquid film CF is formed, it is assumed that the chemical liquid nozzle 4 is located closer to the center portion CT side of the substrate W than the position on the peripheral edge portion E side of the substrate W (for example, the symbol PS1 of FIG. 11) (for example, When the symbol of 11 is PS2). In this case, the moving speed of the substrate W with respect to the chemical liquid nozzle 4 is formed to be faster than the moving speed of the chemical liquid nozzle 4 at the side of the peripheral portion E (symbol PS1). In other words, the closer the chemical liquid nozzle 4 is to the center portion CT side than the peripheral edge portion E of the substrate W, the faster the moving speed of the chemical liquid nozzle 4 is. Efficiency The spiral forms a liquid chemical film CF.

Further, the liquid chemical film CF (including the first spiral-shaped liquid chemical film CF) in each of the spiral chemical liquid films CF is preferably not in the radial direction of the substrate W with the chemical liquid film CF of the adjacent ring. The gaps are overlapped with each other. (a) in Fig. 12 is a preferred example. For example, the chemical liquid film CF of the n-1th circle and the chemical liquid film CF of the nth circle overlap each other. On the other hand, (b) in Fig. 12 is a poor example. For example, the chemical liquid film CF of the n-1th turn is separated from the chemical liquid film CF of the nth turn, and a gap is generated. When a gap is formed between the chemical liquid film CF of each turn and the chemical liquid film CF of the adjacent ring, even in the step S05 described later, the substrate W is rotated at a high speed to expand the liquid medicine of the liquid pool PD described later. There is still a case where the gap is avoided or the recess H existing in the gap is prevented from flowing. For this reason, the liquid medicine of the liquid pool PD can be well expanded by not generating the gap. Moreover, as long as they overlap each other, the liquid medicine of the liquid pool PD can be expanded more surely.

[Step S04: Formation of liquid pool of liquid medicine]

It is assumed that the center of the chemical liquid nozzle 4 reaches the upper side of the center portion CT while forming the chemical liquid film CF in a spiral shape. Thereafter, after the spiral chemical liquid film CF is formed, the control unit 37 further discharges the chemical liquid from the chemical liquid nozzle 4 to the substantially central portion CT of the substrate W. Thereby, a liquid pool (paddle) PD of the chemical liquid is formed in the center portion CT of the substrate W (see FIG. 13). The discharge of the chemical liquid for forming the liquid pool PD is performed in a state where the movement of the chemical liquid nozzle 4 is stopped above the center portion of the substrate W. The liquid pool PD is formed while rotating the substrate W. The liquid pool PD of the liquid is formed as a ratio The spiral liquid film CF is higher. The liquid pool PD is formed on the spiral liquid chemical film CF. Further, by changing the height or amount of the liquid pool PD, the thickness of the chemical liquid film CF after the step S05 described later can be adjusted.

After the liquid pool PD of the chemical liquid is formed, the discharge of the chemical liquid is stopped. Thereafter, after the chemical liquid nozzle 4 is raised, the chemical liquid nozzle 4 is horizontally moved and retracted to the standby container 10. At this time, the substrate W is also rotated at the first rotational speed set in advance.

[Step S05: High-speed rotation of the substrate]

After the liquid pool PD of the chemical liquid is formed and the chemical liquid nozzle 4 is raised or returned to the standby container 10, the control portion 37 is second faster than the first rotational speed for forming the chemical liquid film CF into a spiral shape. The rotation speed causes the substrate W to rotate. Thereby, as shown by the dotted arrow in (a) of FIG. 14, the liquid medicine of the liquid pool PD is expanded to cover the annular and spiral liquid chemical film CF. The liquid medicine of the liquid pool PD is equally expanded along the spiral liquid chemical film CF. Moreover, the chemical solution of the unevenness liquid pool PD on the surface of the annular and spiral chemical liquid film CF is flat, and the film thickness can be made uniform. Moreover, the solvent of the concave portion H can be replaced with the chemical liquid by the rotation (high-speed rotation) of the second rotation speed of the substrate W (see an enlarged view of (b) in FIG. 14). Further, the second number of rotations is set in advance, and is, for example, 750 rpm or more.

The holding rotary unit 2 adjusts the second and second adjustments after the substrate W is rotated at the second rotation speed and the chemical liquid film CF such as a spiral is covered with the chemical liquid of the liquid pool PD. The rotation speed is used to rotate the substrate W, and the film thickness is adjusted. Thereby, the substrate W having the concave portion H and having the unevenness is not broken, and the chemical liquid film CF having a uniform film thickness as shown in FIG. 14(b) and adjusted to the target film thickness can be formed.

After the chemical liquid film CF is formed by the above steps, the solvent is ejected from a nozzle (not shown) to perform EBR (Edge Bead Removal) which removes the chemical liquid film CF formed on the peripheral portion E of the substrate W. The treatment is removed (also referred to as edge rinse treatment), or the backside rinse treatment is performed by discharging the cleaning liquid to clean the back surface of the substrate W. Thereafter, in a state where the rotation of the substrate W is stopped, the holding of the rotating portion 2 releases the holding of the substrate W. The substrate transfer mechanism (not shown) carries out the substrate W from the holding rotary unit 2 .

According to the present embodiment, the spiral chemical liquid film CF is formed before the liquid pool PD of the chemical liquid is formed on the substrate W. The liquid medicine of the liquid pool PD is well fused with the spiral liquid chemical film CF. For this reason, when the substrate W is rotated to expand the liquid medicine of the liquid pool PD to cover the spiral liquid chemical film CF, the liquid medicine of the liquid pool PD is favorably expanded. Further, when the liquid medicine of the liquid pool PD is expanded, the unevenness of the surface of the spiral chemical liquid film CF can be made flat. By this, it is possible to prevent the film M of (a) in FIG. 16 and the pit N of (b) in FIG. 16 and to form a film of high viscosity liquid film CF on the substrate W. Uniform.

Further, after the liquid pool PD is formed at the center portion of the substrate W, when the snail is formed When the film of the liquid film CF is rotated, the liquid medicine of the liquid pool PD is dried. In this case, when the circular substrate W is rotated at the second rotation speed (high-speed rotation), the liquid pool PD does not spread well, and the chemical film CF is closer to the center than the peripheral portion E of the circular substrate. The CT is raised. However, since the liquid pool PD is formed after the formation of the spiral chemical liquid film CF, the liquid medicine PD is not dried, and the liquid pool PD can be well expanded. Further, since the chemical solution can be spread well, no excess chemical solution is discharged for the purpose of expansion. For this reason, the liquid medicine can be saved.

Further, when the liquid pool PD of the chemical liquid is not formed and the circular substrate is rotated at the second rotation speed (high-speed rotation), the spiral pattern of the spiral chemical liquid film CF remains. After forming the spiral liquid chemical film CF, the liquid pool PD of the chemical liquid is formed, and the liquid medicine of the liquid pool PD is expanded. For this reason, the film thickness can be made uniform without leaving a spiral pattern.

Further, when the spiral chemical liquid film CF is formed, the chemical liquid nozzle 4 moves from the peripheral edge portion E of the substrate W toward the central portion CT of the substrate W in the radial direction of the substrate W. After the spiral drug solution CF is formed, the drug solution nozzle 4 is positioned above the center portion of the substrate W. For this reason, the chemical liquid nozzle 4 can directly perform the operation of forming the liquid pool PD. That is, the liquid pool PD of the chemical liquid can be formed efficiently.

Further, the pre-wet treatment is performed, and the substrate W is rotated before the chemical liquid is discharged from the chemical liquid nozzle 4, and the solvent is spit from the solvent nozzle 3. The process of forming the solvent film SF on the substrate W by discharging onto the substrate W. When the spiral chemical liquid film CF is to be formed without pre-wetting treatment, the discharged chemical liquid is agglomerated in the vicinity of the discharge port 4a of the chemical liquid nozzle 4, and in some cases, the chemical liquid is less likely to adhere to the substrate W. However, the chemical solution can be easily attached to the substrate W by the pre-wetting treatment. Further, the chemical liquid easily flows in the portion where the solvent film SF on the substrate W exists.

Further, the pre-wet treatment is in a state in which the solvent has entered the concave portion H formed in the substrate W. Since the solvent has entered the concave portion H, replacement with the chemical liquid is easy. Therefore, it is possible to prevent the filling of the chemical liquid in the concave portion H (see FIG. 15).

The present invention is not limited to the above embodiment, and can be modified as follows.

(1) In the above-described embodiment, as shown in (b) of Fig. 2, the discharge port 4a of the chemical liquid nozzle 4 has a rectangular shape. Thereby, the area coated by one rotation can be increased. For this reason, it is possible to shorten the discharge time and the coating operation in a state in which the liquid column is stabilized with low rotation. However, the discharge port 4a is not limited to a rectangular shape. For example, the discharge port 4a may be a regular polygon, an ellipse or a circle having a polygonal shape, a square shape or the like.

(2) In the above-described embodiment and modification (1), when the spiral drug solution CF is formed, the drug solution nozzle 4 is oriented from the peripheral portion E of the substrate W. The central portion CT of the substrate W moves in the radial direction of the substrate W. However, it can also be moved in the reverse direction. In other words, the chemical liquid nozzle 4 can also move in the radial direction of the substrate W from the central portion CT of the substrate W toward the peripheral edge portion E of the substrate W.

In this case, after the chemical liquid film CF is formed into a spiral shape, a ring-shaped chemical liquid film CF (final ring) is formed along the peripheral edge portion E. Thereafter, the chemical liquid nozzle 4 is moved toward the upper side of the center portion CT of the substrate W to form the liquid pool PD on the central portion CT of the substrate W. Further, in order to form the liquid pool PD, a chemical liquid nozzle (not shown) different from the chemical liquid nozzle 4 (not shown) may be prepared. Thereby, after the spiral and annular chemical liquid film CF is formed, the chemical liquid can be discharged from the second chemical liquid nozzle that has moved upward toward the center portion CT in advance, and the liquid pool PD is immediately formed without vacancy.

After the liquid pool PD is formed, the substrate W is rotated at a high speed, thereby expanding the liquid medicine of the liquid pool PD to cover the spiral and annular chemical liquid film CF. Further, in the case of the present modification, the conditions of the clearance CL, the rotational speed of the substrate W, and the moving speed of the chemical liquid nozzle 4 are the same as those of the above-described embodiment.

(3) In the above-described embodiment and each modification, the clearance CL between the front end surface 4c of the chemical liquid nozzle 4 and the surface of the substrate W, the rotation speed of the substrate W, and the moving speed of the liquid chemical nozzle 4 are made. The conditions change to form a spiral and annular liquid chemical film CF. However, you can also not make it as needed Any one of the conditions changes. That is, at least one of the clearance CL, the rotation speed of the substrate W, and the moving speed of the chemical liquid nozzle 4 may be changed in accordance with the movement of the chemical liquid nozzle 4 to form a spiral and annular chemical liquid film CF.

(4) In the examples and the respective modifications described above, a resin is used as the high viscosity liquid chemical system. However, a resisting agent such as a photoresist, an adhesive, or a flattening film forming chemical liquid such as SOG (Spin on Glass) may be used.

(5) In the above-described embodiment and each of the modifications, the holding rotating portion 2 rotates the substrate W. However, the solvent nozzle moving mechanism 21 can also rotate the solvent nozzle 3 with respect to the substrate W about the rotation axis AX1. Further, the chemical liquid nozzle moving mechanism 23 can also rotate the chemical liquid nozzle 4 with respect to the substrate W about the rotation axis AX1.

(6) In the above-described embodiment and each modification, the solvent nozzle moving mechanism 21 moves the solvent nozzle 3, and the chemical liquid nozzle moving mechanism 23 moves the chemical liquid nozzle 4. However, the holding of the rotating portion 2 can also move the substrate W relative to the solvent nozzle 3 or the chemical liquid nozzle 4.

(7) In the above-described embodiment and each modification, the liquid pool PD is formed on the spiral liquid chemical film CF. However, the spiral liquid film CF can also be stopped before the center portion CT, and the liquid medicine can be moved from the middle to the middle. The liquid chemical nozzle 4 above the heart CT is discharged to form a liquid pool PD. That is, the liquid pool PD may not be formed on the spiral liquid chemical film CF, but may be formed directly on the substrate W.

Claims (8)

A coating method for supplying a high-viscosity chemical solution of 300 cP or more to a circular substrate and forming a chemical liquid film on the circular substrate; the coating method has the following steps: the circular substrate is rotated at a first speed Rotating and moving the chemical liquid nozzle located above the circular substrate toward the radial direction of the circular substrate, and discharging the chemical solution from the chemical liquid nozzle onto the circular substrate, thereby forming the circular substrate a spiral-shaped chemical liquid film is formed on substantially the entire surface; after the spiral liquid chemical film is formed, the chemical liquid is discharged from the chemical liquid nozzle to a central portion of the circular substrate, thereby being at the center of the circular substrate a liquid pool for forming a chemical liquid; and, after forming the liquid pool of the chemical liquid, rotating the circular substrate at a second rotation speed faster than the first rotation speed, thereby expanding the liquid medicine of the liquid pool to cover the foregoing The spiral drug solution film flattens the surface of the aforementioned spiral drug solution. The coating method according to claim 1, wherein the chemical liquid nozzle is formed from a peripheral portion of the circular substrate toward a central portion of the circular substrate along the circular substrate when the spiral drug solution is formed Move in the radial direction. The coating method according to claim 1 or 2, further comprising the step of rotating the circular substrate at the first rotational speed and from the circular base in a state where the movement of the chemical liquid nozzle has been stopped The chemical liquid nozzle above the peripheral portion of the plate discharges the chemical solution onto the circular substrate, thereby forming a ring-shaped chemical liquid film along the peripheral edge portion of the circular substrate. The coating method according to claim 1 or 2, further comprising a step of performing a pre-wet treatment, wherein the pre-wetting treatment is performed by rotating the circular substrate before ejecting the chemical solution from the liquid chemical nozzle, and from the solvent nozzle The solvent is discharged onto the circular substrate, whereby a solvent film is formed on the circular substrate. The coating method according to claim 4, wherein the pre-wetting treatment is in a state in which the solvent has entered the concave portion formed in the circular substrate. The coating method according to claim 1 or 2, wherein the chemical liquid film of each of the spiral liquid chemical films does not have a gap with the chemical liquid film of the adjacent ring in the radial direction. The coating method according to claim 1 or 2, wherein, when the spiral liquid chemical film is formed, the chemical liquid nozzle is located closer to a central portion of the circular substrate than a peripheral portion of the circular substrate In the side, the clearance between the front end surface of the chemical liquid nozzle and the surface of the circular substrate is formed to be larger than the aforementioned clearance in the position on the peripheral edge side. The coating method according to claim 1 or 2, wherein, when the spiral liquid chemical film is formed, the chemical liquid nozzle is located closer to a central portion of the circular substrate than a peripheral portion of the circular substrate In the side, the rotation speed of the circular substrate is formed to be faster than the aforementioned rotation speed when the peripheral portion side is located.