JP5183562B2 - Coating film forming apparatus and coating film forming method - Google Patents

Description

  The present invention relates to a coating film forming apparatus and a coating film forming method for forming a coating film such as a resist film on the surface of a substrate to be processed used for a semiconductor wafer, an FPD (flat panel display) or the like.

For example, in a photolithography process in a semiconductor device manufacturing process, a resist coating process for forming a resist film on the surface of a semiconductor wafer and a predetermined pattern exposure process are performed on the semiconductor wafer after the resist coating. Development processing for developing is performed.
In this resist coating process, a spin coating method or the like is frequently used as a method for uniformly coating a resist solution on the surface of a semiconductor wafer.

FIG. 7 shows an outline of a conventional coating processing unit using this spin coating method. In FIG. 7, for example, the wafer W is rotated together with the spin chuck 201 in a state where the wafer W is fixedly held by vacuum chucking by the spin chuck 201. A resist solution is dropped.
The dropped resist solution spreads outward in the radial direction of the wafer W by centrifugal force, and then the dropping of the resist solution is stopped, the wafer W is rotated at a predetermined speed, and the remaining resist is shaken off and dried. Yes. As a result, a resist film having a predetermined film thickness is formed on the wafer W.

  In order to efficiently apply a resist solution discharged from a resist nozzle onto a semiconductor wafer with a low consumption, Patent Document 1 discloses a so-called pre-wet process in which a substrate surface is wetted with a solvent prior to application of the resist solution. A coating film forming method that suppresses a decrease in film thickness is disclosed.

The coating film forming method disclosed in Patent Document 1 will be described with reference to FIGS.
First, as shown in FIG. 8, the thinner nozzle 203 is moved to the center of the wafer W, and the thinner T as a solvent is discharged.
Next, the resist nozzle 204 is shifted so as to be positioned at the center of the wafer W, while the wafer W is rotated at a low speed for a predetermined minute time, and the thinner T on the discharged wafer W is diffused in the radial direction.
Then, after the diffusion of the thinner T, as shown in FIG. 9, the resist solution R is discharged from the resist nozzle 204 onto the rotating wafer W, and the resist solution R is spread by centrifugal force to form a resist film.

According to the coating film forming method disclosed in Patent Document 1, since the solvent (thinner T) is diffused immediately before discharging the resist solution R, the resist solution R can be used even when a highly volatile thinner is used as the solvent. At the time of discharging, the drying of the solvent hardly proceeds.
For this reason, even when the coating solution reaches the peripheral portion of the substrate, the highly volatile thinner sufficiently wets the substrate, so that the effect of the pre-wet treatment can be sufficiently exhibited.

JP 2000-288458 A

Incidentally, in the conventional coating film forming method disclosed in Patent Document 1, as schematically shown in the side view of FIG. 10A and the plan view of FIG. The outlet is disposed above the center of the wafer W.
In such an arrangement of the resist nozzle 204, when the supply of the resist solution R is started to the center of the wafer W, the wafer is immediately after the resist solution R is discharged from the nozzle 204 as shown in FIG. The edge thickness of the resist solution R on W is ensured, and the resist solution R spreads in a circular shape as shown in FIG.

However, as the supply of the resist solution R onto the wafer W proceeds as shown in FIG. 12A, the thickness of the peripheral portion of the resist solution R spreading in a circular shape on the wafer W is reduced. . For this reason, the peripheral portion of the resist solution R supplied onto the wafer W does not have a sufficient amount of solution for maintaining the circular shape, and may branch out and expand as shown in the plan view of FIG. was there.
That is, as shown in FIG. 12B, when the resist solution R branches and spreads on the wafer W, the resist coating efficiency decreases, and the resist solution R is uniformly distributed on the wafer W even if pre-wet processing is performed. There has been a problem that the amount of resist solution and the time required for coating and formation increase.

  The present invention has been made in view of the above-described problems of the prior art. In a coating film forming apparatus for forming a coating film on a substrate, the coating film is efficiently formed on the substrate, An object is to provide a coating film forming apparatus and a coating film forming method capable of reducing consumption.

  In order to solve the above-described problems, a coating film forming apparatus according to the present invention is a coating film forming apparatus that forms a coating film on a substrate, and holds the substrate and rotates the substrate at a predetermined rotational speed. A substrate rotating means for rotating the substrate, a first nozzle for discharging a coating liquid onto the surface to be processed of the substrate rotated by driving the substrate rotating means, and an outer edge side of the substrate above the first nozzle above the substrate. And a second nozzle for discharging a high surface tension liquid having a surface tension higher than that of the coating liquid, and the first nozzle and the second nozzle along the radial direction of the substrate. Nozzle moving means for moving from the central part toward the outer edge side, and the first nozzle and the second nozzle are disposed above the substrate rotated by the substrate rotating means by the nozzle moving means. From the center to the outer edge While moving toward, characterized in that the discharging said coating solution and the said high tension liquid to each of the substrate.

By configuring in this way, the coating liquid is always supplied from above to the peripheral edge of the coating liquid spreading on the substrate, and the thickness of the peripheral edge of the coating liquid on the substrate can be sufficiently secured. it can.
Furthermore, since an annular wall can be formed outside the coating liquid spreading on the substrate by a high surface tension liquid having a higher surface tension than the coating liquid, branching of the coating liquid can be reliably prevented. .

The third nozzle is disposed between the first nozzle and the second nozzle and discharges a solvent that improves the wettability of the surface to be processed of the substrate. It is preferable that the nozzle is moved together with the first nozzle and the second nozzle from the center of the substrate toward the outer edge side, and the solvent is discharged onto the substrate while moving on the substrate.
Alternatively, the high surface tension liquid discharged from the second nozzle may be a solvent that improves the wettability of the surface to be processed of the substrate.
Thus, the coating liquid can be efficiently spread on the substrate by improving the wettability of the surface to be processed with the solvent before the resist application.

Further, while the first nozzle moves along the radial direction of the substrate from the center portion of the substrate to the outer edge side, the linear velocity of the surface to be processed of the substrate facing the discharge port of the first nozzle is It is desirable that the rotation speed of the substrate is controlled to be constant.
Alternatively, the coating liquid supply amount per unit area supplied by the first nozzle onto the substrate while the first nozzle moves along the radial direction of the substrate from the center of the substrate to the outer edge side. The discharge amount of the first nozzle may be controlled so that is constant.
With such a configuration, the coating liquid supply amount per unit area on the substrate can be made constant, and the thickness of the coating film can be easily made uniform.

  In order to solve the above-described problem, a coating film forming method according to the present invention is a coating film forming method in which a coating liquid is discharged from a first nozzle onto a surface to be processed of a substrate to form a coating film on the substrate. In the method, the substrate is held, the substrate is rotated at a predetermined rotation number, and the first nozzle and the outer edge side of the substrate are arranged above the first nozzle above the substrate. A second nozzle is moved along the radial direction of the substrate from the center of the substrate toward the outer edge, and during the step, the coating liquid is applied from the first nozzle onto the substrate. It is characterized by discharging and discharging a high surface tension liquid having a surface tension higher than that of the coating liquid from the second nozzle.

By such a method, the coating liquid is always supplied from above to the peripheral edge of the coating liquid spreading on the substrate, and the thickness of the peripheral edge of the coating liquid on the substrate can be sufficiently secured.
Furthermore, since an annular wall can be formed outside the coating liquid spreading on the substrate by a high surface tension liquid having a higher surface tension than the coating liquid, branching of the coating liquid can be reliably prevented. .

Further, while the first nozzle moves along the radial direction of the substrate from the substrate center to the outer edge side, the linear velocity of the surface to be processed of the substrate facing the discharge port of the first nozzle is constant. It is desirable to control the rotation speed of the substrate so that
Alternatively, the coating liquid supply amount per unit area supplied by the first nozzle onto the substrate while the first nozzle moves along the radial direction of the substrate from the center of the substrate to the outer edge side. The discharge amount of the first nozzle may be controlled so that is constant.
By performing such control, the coating liquid supply amount per unit area on the substrate can be made constant, and the thickness of the coating film can be easily made uniform.

  According to the present invention, in a coating film forming apparatus for forming a coating film on a substrate, the coating film forming apparatus and the coating film formation capable of efficiently forming the coating film on the substrate and reducing the consumption of the coating liquid. You can get the method.

FIG. 1 is a schematic cross-sectional view showing an overall configuration of a resist coating unit which is an embodiment according to the present invention. FIG. 2 is a schematic plan view showing the overall configuration of a resist coating unit which is an embodiment according to the present invention. FIG. 3 is a flowchart showing a flow of operation of the resist coating process by the resist coating unit of FIG. FIG. 4 is a view for explaining the process of resist coating processing by the resist coating processing unit of FIG. FIG. 5 is a diagram for explaining a process of resist coating processing by the resist coating processing unit of FIG. FIG. 6 is a view for explaining the process of resist coating processing by the resist coating processing unit of FIG. FIG. 7 is a diagram for explaining a conventional spin coating method. FIG. 8 is a diagram for explaining a coating film forming method by a conventional prewetting process. FIG. 9 is another diagram for explaining a coating film forming method by a conventional pre-wet process. FIG. 10 is a diagram for explaining a problem when the conventional spin coating method is used. FIG. 11 is another diagram for explaining a problem when the conventional spin coating method is used. FIG. 12 is another diagram for explaining a problem when the conventional spin coating method is used.

  Hereinafter, embodiments of a coating film forming apparatus and a coating film forming method according to the present invention will be described with reference to the drawings. The coating film forming apparatus of the present invention can be applied to, for example, a configuration in which a semiconductor wafer is a substrate to be processed (hereinafter referred to as a substrate) and resist coating is performed in a photolithography process in a semiconductor device manufacturing process.

FIG. 1 and FIG. 2 are a schematic cross-sectional view and a schematic plan view showing an overall configuration of a resist coating processing unit 1 which is a resist coating processing unit as a coating film forming apparatus used in the present embodiment.
An annular cup 2 is disposed at the center of the resist coating unit 1, and a spin chuck 3 is disposed inside the cup 2 as shown in FIG. The spin chuck 3 is rotationally driven by a drive motor 4 while the wafer W is fixedly held by vacuum suction. The spin chuck 3 and the drive motor 4 constitute a substrate rotating means.

  The drive motor 4 is disposed in an opening 5a provided in the unit bottom plate 5 so as to be movable up and down. The drive motor 4 is, for example, a lift drive means 7 and a lift guide means 8 made of an air cylinder, for example, via a cap-like flange member 6 made of aluminum. Are combined. A cylindrical cooling jacket 9 made of, for example, SUS is attached to the side surface of the drive motor 4, and the flange member 6 is attached so as to cover the upper half of the cooling jacket 9.

At the time of resist application, the lower end 6a of the flange member 6 is in close contact with the unit bottom plate 5 in the vicinity of the outer periphery of the opening 5a, thereby sealing the inside of the unit.
When the wafer W is transferred between the spin chuck 3 and the holding member 50 of the wafer transfer mechanism (not shown), the elevating drive means 7 lifts the drive motor 4 or the spin chuck 3 upward so that the flange member. The lower end of 6 is made to float from the unit bottom plate 5.

A resist nozzle 10 (first nozzle) for discharging a resist solution, which is a coating solution, to the surface of the wafer W is connected to a resist supply tube 11, and the resist solution is supplied to the resist supply tube 11. A resist supply unit 12 is connected.
The resist supply unit 12 includes an air operation valve, a suck back valve, a resist storage tank, and the like.

The resist nozzle 10 is detachably attached to the tip of a resist nozzle scan arm 20 via a nozzle arm 21.
The registration nozzle scan arm 20 is attached to an upper end portion of a vertical support member 23 that is horizontally movable on a guide rail 22 laid in one direction (Y direction) on the unit bottom plate 5, and has a Y direction drive mechanism. (Not shown) moves together with the vertical support member 23 in the Y direction.

The resist nozzle scan arm 20 is also provided so as to be movable in the X direction by the X direction drive mechanism 13 (nozzle moving means), whereby the resist nozzle 10 is centered on the wafer W along the radial direction (X direction). The resist solution is discharged while moving from the portion toward the outer edge of the wafer.
More specifically, when the resist solution is supplied from the resist nozzle 10 to the central portion of the wafer W and the wafer W sucked and held by the spin chuck 3 is rotated, the resist solution on the wafer W is circular due to the centrifugal force acting on the wafer W. In this configuration, the resist nozzle 10 is further linearly moved from the central portion of the wafer W toward the outer edge side along with the supply of the resist solution.
With this configuration, the resist nozzle 10 is always positioned above the peripheral portion of the resist solution spreading on the wafer W, and the resist solution on the wafer W is sufficient to maintain a circular shape with respect to the resist peripheral portion. A sufficient amount of liquid can be supplied.

Further, since the resist nozzle scan arm 20 is movable in the XY directions, the resist nozzle 10 can be selectively attached to the nozzle arm 21 in the resist nozzle standby section 30.
Further, in the resist nozzle standby unit 30, the discharge port of the resist nozzle 10 is inserted into the solvent atmosphere chamber port 30a and exposed to the solvent atmosphere therein, so that the resist solution at the nozzle tip is not solidified or deteriorated. It has become. Further, the resist standby section 30 is provided with a plurality of resist nozzles 10, and these nozzles can be used properly according to the type of resist solution, for example.

Further, the nozzle arm 21 provided at the tip of the resist nozzle scan arm 20 is arranged as a high surface tension liquid that is arranged at least on the wafer outer edge side than the resist nozzle 10 at the time of resist coating and has a higher surface tension than the resist liquid. For example, a wall liquid nozzle 25 (second nozzle) for discharging pure water is provided.
While the resist liquid is discharged from the resist nozzle 10, pure water is discharged from the wall liquid nozzle 25, so that a wall of pure water is formed around the resist liquid spreading in a circular shape. R can be prevented from branching and spreading.

Further, a solvent nozzle such as a thinner is discharged onto the surface of the wafer W between the resist nozzle 10 and the wall liquid nozzle 25 to the nozzle arm 21 to improve the wettability of the surface of the wafer W ( A third nozzle) is provided.
That is, the thinner nozzle 24 is disposed on the wafer outer edge side with respect to the resist nozzle 10 at the time of resist coating, and while the resist solution is discharged from the resist nozzle 10, the thinner is discharged from the thinner nozzle 24. The wettability of the surface to be processed before resist application is improved, and the resist solution can be efficiently spread on the wafer W.

The arrangement of the nozzles will be described in more detail. The resist nozzle 10, the thinner nozzle 24, and the wall liquid nozzle 25 are directed from the top of the wafer toward the outer edge of the wafer at the start of resist coating (the state shown in FIGS. The discharge ports are arranged on a straight line along the X movement direction of the nozzle arm 21.
The thinner nozzle 24 is connected to a thinner supply section 31 for supplying thinner via the solvent supply pipe 14, and the wall liquid nozzle 25 is for wall supply for supplying pure water via the wall liquid supply pipe 15. The liquid supply unit 32 is connected.

In addition to the vertical support member 23 that supports the resist nozzle scan arm 20, a vertical support member that supports the rinse nozzle scan arm 27 and is movable in the Y direction is also provided on the guide rail 22 as shown in FIG. It has been.
A rinse nozzle 28 for side rinse is attached to the tip of the rinse nozzle scan arm 27. The rinse nozzle scan arm 27 and the rinse nozzle 28 are arranged in the rinse nozzle standby position (solid line position) set on the side of the cup 2 and the wafer installed on the spin chuck 3 by a Y-direction drive mechanism (not shown). Translation or linear movement is performed with respect to the rinse liquid discharge position (dotted line position) set immediately above the peripheral portion of W.

Further, as shown in FIG. 1, the resist coating unit 1 includes a coating unit controller 40, and each unit in the resist coating unit 1 is controlled by the coating unit controller 40.
Specifically, a spin chuck 3 (drive motor 4) for rotating the wafer W, an X-direction drive mechanism 13 for moving the resist nozzle scan arm 20 in the X direction, and a resist supply unit for supplying or stopping the resist solution 12, a thinner supply unit 31 for supplying or stopping thinner, a wall liquid supply unit 32 for supplying or stopping pure water, and the like are driven and controlled.

In the resist coating unit 1 configured as described above, the resist solution is applied by a coating process along the flow shown in FIG.
First, the wafer W is carried into the resist coating unit 1 just above the cup 2, and then the wafer W is vacuum-sucked by the spin chuck 3. The wafer W on the spin chuck 3 starts to rotate at a predetermined speed (for example, 1000 rpm) (step S1 in FIG. 3).

Further, as schematically shown in the side view of FIG. 4A, the resist nozzle 10 is disposed on the central axis C passing through the wafer center, and the thinner nozzle 24 and the wall liquid are disposed outside (on the wafer outer edge side). The nozzles 25 are arranged in order (step S2 in FIG. 3).
In this state, discharge of each liquid (resist liquid R, thinner T, pure water G) from each nozzle is started simultaneously (step S3 in FIG. 3).

As a result, on the rotating wafer W, as shown in FIG. 4B, a film of the resist solution R is formed in a circular shape at the center of the wafer by centrifugal force, and a film of the thinner T is formed in an annular shape around the film. Further, a wall of pure water G is formed in an annular shape around the thinner T.
Here, since the wettability on the surface of the wafer W is improved by the thinner T discharged from the thinner nozzle 24, the resist solution R spreads efficiently on the wafer W.
Further, since the annular wall is formed around the resist solution R by the pure water G discharged from the wall liquid nozzle 25, the resist R is maintained in a circular shape on the wafer W.

While the resist solution R supplied on the wafer W spreads in a circular shape, the nozzle arm 21 is moved in the X direction (radial direction) by the X direction drive mechanism 13 as shown in FIGS. 5 (a) and 5 (b). Are moved from the wafer central portion toward the wafer outer edge side (step S4 in FIG. 3).
Here, the movement of the nozzle arm 21 is performed so that the discharge port of the resist nozzle 10 is always positioned on the peripheral edge of the resist solution R (the front end portion of the resist solution R) spreading in a circular shape on the wafer W. The moving speed (for example, 50 to 150 mm / s) is controlled by 40.
With this control, even if the resist solution R is greatly expanded in a circular shape on the wafer W, the thickness t of the peripheral portion is sufficiently secured.

Further, the rotation speed of the wafer W is made constant by the coating unit controller 40 so that the linear velocity of the surface to be processed of the wafer W facing the discharge port of the resist nozzle 10 moving in the X direction (radial direction) is constant. Be controlled.
Alternatively, when the rotation speed of the wafer W is constant, the driving of the resist supply unit 12 is controlled so that the resist supply amount per unit area supplied to the wafer W is constant.
That is, by such control, the resist supply amount per unit area on the wafer W can be made constant, and the resist film thickness can be easily made uniform.

Further, the nozzles 10, 24, and 25 are held in a positional relationship, and the nozzles move and discharge from all the nozzles at the same time. Therefore, there is a wall outside the resist solution R spreading on the wafer W. The pure water G discharged from the liquid nozzle 25 is always formed in an annular shape and functions as a wall, and branching of the resist solution R is prevented. Further, the thinner T discharged from the thinner nozzle 24 improves the wettability of the surface to be processed before resist application, and the resist solution R efficiently spreads on the wafer W.
Therefore, as shown in FIGS. 6A and 6B, even when the resist solution R is greatly spread on the wafer W, the resist solution R is maintained in a circular shape, and the resist solution R is consumed in excess. Thus, film formation can be performed efficiently.

When the discharge of the resist solution R from the resist nozzle 10 is completed on the entire wafer W, the wafer W is rotated at a predetermined rotation speed (for example, 2000 rpm) for 1 second (step S5 in FIG. 3). As a result, the resist film can be uniformly distributed over the entire area of the wafer W with a predetermined thickness.
Next, the rotation speed of the wafer W is accelerated (3000 rpm) and rotated for 25 seconds, and the remaining resist solution R is shaken off (step S6 in FIG. 3). At this time, the nozzle arm 21 is returned to the home position.

Subsequently, the rotational speed of the wafer W is reduced (for example, 1500 rpm), and the wafer W is rotated at this rotational speed for 5 seconds. At this time, the rinse nozzle 28 is moved to a position inside by 1 mm from the outer edge of the wafer W.
Then, with the wafer W rotated without changing the rotation speed of the wafer W, the rinse liquid is discharged from the rinse nozzle 28 for a predetermined time (for example, 1 second) to clean the outer edge portion of the wafer W. (Step S7 in FIG. 3).

When the discharge of the rinse liquid from the rinse nozzle 28 is stopped and the cleaning of the outer edge of the wafer is completed, the rotational speed of the wafer W is accelerated, and the wafer W is rotated at a rotational speed of, for example, 2000 rpm for 5 seconds. During this time, the rinse nozzle 28 is returned to the home position. Here, since the step of stopping the discharge of the rinsing liquid is provided before the rinsing nozzle 28 is returned to the home position in this manner, the rinsing liquid from the rinsing nozzle 28 is inadvertently applied to the wafer W. Can be prevented.
Further, simultaneously with the return of the rinse nozzle to the home position, the rinse liquid on the wafer W is shaken off by accelerating the rotation speed of the wafer W (step S8 in FIG. 3).
After all these processes are completed, the rotation of the wafer W is decelerated and stopped, and the coating process is completed.

As described above, according to the embodiment of the present invention, when the resist solution is applied to the wafer W held by the spin chuck 3, the resist nozzle 10 is disposed at the center of the wafer W at the start of application, and the wall The liquid nozzle 25 is disposed on the wafer outer edge side with respect to the resist nozzle 10.
Then, the resist liquid is discharged from the resist nozzle 10 to the surface to be processed of the rotating wafer W, pure water is discharged from the wall liquid nozzle 25, and each nozzle is maintained in a state where the positional relationship between the nozzles is maintained. Is controlled to move toward the outer edge of the wafer along the wafer radial direction.
In particular, the movement of the resist nozzle 10 is controlled so as to be positioned above the peripheral edge in accordance with the peripheral edge of the resist solution spreading in a circular shape by the centrifugal force of the rotating wafer W.
That is, since the resist solution is always supplied from above to the peripheral portion of the resist solution spreading on the wafer W, a sufficient thickness of the resist peripheral portion can be ensured.
Furthermore, since an annular wall made of pure water having a higher surface tension than the resist solution can be formed outside the resist solution spreading on the wafer W, branching of the resist solution can be reliably prevented.

In the above embodiment, pure water is used as an example of the liquid discharged from the wall liquid nozzle 25, that is, a liquid having a higher surface tension than the resist liquid. However, in addition to pure water, γ-butyrolactone, cyclohexanone An aqueous solution such as can also be used.
Further, when the high surface tension liquid discharged from the wall liquid nozzle 25 is a solvent having a wettability modification effect on the wafer W, the coating film forming apparatus according to the present invention includes the thinner nozzle 24. The structure which does not do may be sufficient.

1 resist coating unit (coating film forming device)
2 cups 3 spin chuck (substrate rotation means)
4 Drive motor (substrate rotation means)
5 Unit bottom plate 6 Flange member 7 Lift drive means 8 Lift guide means 9 Cooling jacket 10 Registration nozzle (first nozzle)
11 resist supply pipe 12 resist supply unit 13 X direction drive mechanism (nozzle moving means)
14 Solvent Supply Pipe 15 Wall Liquid Supply Pipe 20 Resist Nozzle Scan Arm 21 Nozzle Arm 22 Guide Rail 23 Vertical Support Member 24 Thinner Nozzle (Third Nozzle)
25 Wall liquid nozzle (second nozzle)
26 Vertical Support Member 27 Rinse Nozzle Scan Arm 28 Rinse Nozzle 31 Thinner Supply Unit 32 Wall Liquid Supply Unit 40 Application Processing Unit Controller G Pure Water (High Surface Tension Liquid)
T thinner (solvent)
W Wafer (Substrate)

Claims (8)

A coating film forming apparatus for forming a coating film on a substrate,
Substrate rotating means for holding the substrate and rotating the substrate at a predetermined rotational speed;
A first nozzle that discharges a coating liquid onto a surface to be processed of the substrate that is rotated by driving the substrate rotating means;
A second nozzle that is disposed on the outer edge side of the substrate above the first nozzle above the substrate and discharges a high surface tension liquid having a higher surface tension than the coating liquid;
Nozzle moving means for moving the first nozzle and the second nozzle from the center of the substrate toward the outer edge side along the radial direction of the substrate;
The first nozzle and the second nozzle are located on the substrate while being moved from the center of the substrate toward the outer edge side by the nozzle moving unit, above the substrate rotated by the substrate rotating unit. A coating film forming apparatus that discharges the coating liquid and the high surface tension liquid, respectively. A third nozzle that is disposed between the first nozzle and the second nozzle and that discharges a solvent that improves the wettability of the surface to be processed of the substrate;
The third nozzle is moved from the center of the substrate toward the outer edge side by the nozzle moving means together with the first nozzle and the second nozzle, and the solvent is placed on the substrate while moving on the substrate. The coating film forming apparatus according to claim 1, wherein the film is discharged.   The coating film forming apparatus according to claim 1, wherein the high surface tension liquid discharged from the second nozzle is a solvent that improves wettability of a surface to be processed of the substrate.   While the first nozzle moves from the center of the substrate to the outer edge side along the radial direction of the substrate, the linear velocity of the surface to be processed of the substrate facing the discharge port of the first nozzle is constant. The coating film forming apparatus according to claim 1, wherein the rotation speed of the substrate is controlled so as to satisfy the above condition.   While the first nozzle moves along the radial direction of the substrate from the center portion of the substrate to the outer edge side, the coating liquid supply amount per unit area supplied onto the substrate by the first nozzle is constant. The coating film forming apparatus according to claim 1, wherein the discharge amount of the first nozzle is controlled so that A coating film forming method for discharging a coating liquid from a first nozzle onto a surface to be processed of a substrate and forming a coating film on the substrate,
While holding the substrate, rotating the substrate at a predetermined number of rotations,
Above the substrate, the first nozzle and a second nozzle disposed on the outer edge side of the substrate with respect to the first nozzle are moved from the center of the substrate to the outer edge side along the radial direction of the substrate. Perform the steps to move
During the step, a coating film is discharged from the first nozzle onto the substrate, and a high surface tension liquid having a surface tension higher than that of the coating liquid is discharged from the second nozzle. Forming method.   While the first nozzle moves from the center of the substrate to the outer edge side along the radial direction of the substrate, the linear velocity of the surface to be processed of the substrate facing the discharge port of the first nozzle becomes constant. The method of forming a coating film according to claim 6, wherein the rotation speed of the substrate is controlled.   While the first nozzle moves along the radial direction of the substrate from the center portion of the substrate to the outer edge side, the coating liquid supply amount per unit area supplied onto the substrate by the first nozzle is constant. The coating film forming method according to claim 6, wherein the discharge amount of the first nozzle is controlled so that

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