JP3248232B2 - Resist coating apparatus and spin coating method for resist - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photolithography in a semiconductor manufacturing process, and more particularly to suppression of film thickness unevenness due to turbulence during photoresist coating.

[0002]

2. Description of the Related Art In recent years, the miniaturization of semiconductor devices has progressed, and accordingly, a high-precision pattern forming technique is required. The required accuracy is generally ± 10% of the design rule
It is. For example, super LS with a design rule of 0.35 μm
In I, accuracy of ± 0.035 μm (pattern line width uniformity) is essential.

The causes of the deterioration of the accuracy, that is, the fluctuation of the line width are, for example, in the photolithography process, the fluctuation of the resist film thickness, the fluctuation of the resist developing speed, the fluctuation of the characteristics of the resist material, and the optical characteristics of the exposure apparatus.・ Mechanical fluctuation, variation of line width of photomask (reticle),
There are variations in the light reflectance of the substrate (variations in the thickness of the oxide film, etc.). In addition, there are other fluctuation factors such as variations in etching and steps due to the underlying pattern.

In consideration of such a line width variation factor, in a super LSI having a design rule of 0.35 μm, the resist film thickness uniformity is required to be 5 nm (50 °) or less.

On the other hand, the diameter of a wafer has been increased to improve productivity, and the wafer diameter is currently 200 m.
m (8 inch) φ is becoming mainstream.

However, as the wafer diameter increases, it becomes more difficult to form a uniform resist film thickness. Naturally, the uniformity is deteriorated because the coating area increases, but another reason is that the number of revolutions during coating cannot be sufficiently increased. To explain this, first, a general coating process will be described with reference to FIG.

In general, photoresist is applied by first holding a wafer 1 on a wafer chuck 2 and then discharging a resist 4 from a resist discharge nozzle 3 (FIG. 38A). Thereafter, the wafer 1 is rotated to form a resist film (FIGS. 38B and 38C). At this time, the resist film thickness is determined by the rotation speed and time.
６6000 r / min.

On the other hand, the number of rotations also affects the film thickness uniformity. The higher the number of rotations, the better the film thickness uniformity. For a wafer diameter of 125 mm (5 inches) φ, 4000 r /
In the case of min or more, sufficient uniformity can be obtained. That is, in order to obtain sufficient film thickness uniformity, the number of revolutions at the time of coating needs to be 4000 r / min or more.

[0009]

However, as the diameter of the wafer increases, the peripheral velocity increases, and turbulence of air tends to occur. When the turbulent flow occurs, the evaporation amount of the solvent of the resist locally changes, and the film thickness largely changes. This is 19
1990, it is described in the Spring Proceedings Lecture Proceedings 28a-PD-14. According to this, a 200 mm (8 inch) wafer can be uniformly coated up to 4000 r / min,
When it exceeds 00 r / min, it is said that turbulence of air causes unevenness in resist film thickness around the wafer.

[0010] According to an experiment conducted by the inventor, the number of rotations was 3500 r.
It has been confirmed that uniformity is good up to / min. 400
At 0 r / min, the turbulent flow of the resist film caused the turbulence from the edge of the wafer to 7 mm [Range 100 nm
(1000 °)] (FIG. 39). The Reynolds number in this case corresponds to 2.35 × 10 ⁵ .

That is, a general coating apparatus cannot apply a resist having a Reynolds number of more than 2.35 × 10 ⁵ . FIG. 13 is a graph of this. From this graph, it can be seen that the rotation speed can be increased only up to 3500 r / min with an 8 inch φ wafer. further,
The wafer diameter will be further increased to 10 inches and 12 inches in the future.
At 0 r / min and 12 inches, it is about 1500 r / min, and the uniformity of the film thickness is further deteriorated.

As a countermeasure, a method of lowering the viscosity of the resist (10 cp) has been considered. By lowering the resist viscosity, the number of rotations is kept low to obtain a desired resist film thickness.However, since the solvent is in a large amount, it is easily affected by the temperature and humidity of the environment and is stable for a long time. Sex worsens.

Therefore, there is a strong demand for a method capable of increasing the number of revolutions to 4000 r / min even when the wafer diameter increases.

An object of the present invention is to provide a resist coating apparatus capable of suppressing generation of turbulence due to high-speed rotation and achieving uniform resist film thickness.

[0015]

Therefore, the invention of claim 1 comprises at least a chuck for holding a substrate, and a rotating means for rotating the chuck, wherein the substrate is attached to the chuck. By holding and rotating in a horizontal plane, in a resist coating apparatus that applies a resist dropped on the substrate to the upper surface of the substrate, the resist coating apparatus is close to and above the substrate held by the chuck, and is parallel to the substrate. A ring-shaped plate is disposed on the substrate, and the width (L) of the ring of the ring-shaped plate is determined by the Reynolds number (Re) and the radius of the substrate (r).
₀ ), the kinematic viscosity coefficient (ν) of air, and the angular velocity (ω) of the substrate ,

[0016]

## EQU5 ## It is characterized by having a relationship of L = r ₀ −√ (Reν / ω).

According to a second aspect of the present invention , the angular velocity (ω ₁ ) of the ring-shaped plate is defined by the angular velocity (ω ₂ ) of the substrate, the radius (r ₀ ) of the substrate, and the kinematic viscosity coefficient of air. Where

[0018]

Ω ₁ −ω ₂ | ≦ (ν / r ₀ ² ) × 2.35 × 10 ⁵ .

According to a third aspect of the present invention, there is provided at least a chuck for holding a substrate, and rotating means for rotating the chuck, wherein the chuck is held by the chuck and rotated in a horizontal plane. In a method of spin-coating a resist, in which a resist dropped on the substrate is applied to an upper surface of the substrate , a ring-shaped plate is disposed close to and above the substrate held by the chuck, and in parallel with the substrate. ,
Assuming that the radius of the substrate is r and the angular velocity of the substrate is ω,

[0020]

## EQU7 ## The coating atmosphere of the substrate is filled with a gas having a kinematic viscosity coefficient larger than the kinematic viscosity coefficient ν represented by ν ≧ r ² ω / 2.35 × 10 ⁻⁵ .

According to a fourth aspect of the present invention, there is provided at least a chuck for holding a substrate, and rotating means for rotating the chuck, wherein the chuck is held by the chuck and rotated in a horizontal plane. In a method of spin-coating a resist in which a resist dropped on the substrate is coated on the upper surface of the substrate, the radius of the substrate is r, the angular velocity of the substrate is ω,
Assuming that the coating atmosphere temperature of the substrate is t, the coating atmosphere of the substrate is represented by the following formula:

[0022]

## EQU8 ## The pressure is characterized by being smaller than the pressure P expressed by P (mmHg) ≦ 2.50 × 10 ³ × (1 + 0.00367t) / r ² ω.

[0023]

(Operation of the Invention of Claims 1 and 2 ) In order to suppress turbulence, the position of the disk-shaped plate becomes a problem.
Then, the inventor calculated the wind speed distribution by the following method to determine how air flows as the wafer rotates.

First, the Navier-Stokes equation is a general equation that considers changes in viscosity and density. However, when the viscosity is fixed, the equation can be simplified as follows.

Navier-S having a real viscosity in cylindrical coordinates
expression of tokens

[0026]

(Equation 9) Here, D / Dt is called a substantial derivative and is defined by the following equation.

[0027]

(Equation 10) The meaning of each symbol is shown below.

[0028] u _r, uφ, u _x: Speed t: Time [rho: Density g: gravitational acceleration h: Height P: Pressure eta: Viscosity K: bulk viscosity, where the central disc is an axis perpendicular to the plane Constant angular velocity ω
Consider a state of rotation at ₀ .

The rotation of the fluid is generated by the disk and moves outward by centrifugal force.

Hereinafter, the disk will be described as a wafer and the fluid as air.

In the equations (1), (2), and (3), since the flow of air on the rotating wafer is rotationally symmetric, δ / δ
ψ = 0. Assuming steady incompression, δu /
δt = 0

[0032]

[Equation 11]

Is as follows. Therefore, the expressions (1), (2) and (3) are as follows.

[0034]

(Equation 12)

On the other hand, a continuous equation (mass conservation law) in cylindrical coordinates is expressed by the following equation.

[0036]

(Equation 13)

Here, under the same conditions as the equations (4), (5) and (6), the continuous equation is as follows.

[0038]

[Equation 14]

If the origin is located on the wafer surface, the boundary conditions are as follows.

[0040] _{u x = 0, u r =} 0 when _{x = 0, uψ = rω 0} x = ∞ u r = 0 when, uψ = 0 Von Karman is _{u r / r, uψ / r} , u x, P '
Are assumed to be functions of only x, respectively (4) to
Equation (7) is simplified to simultaneous differential equations. The method is described below.

A new variable λ was defined as follows.

Λ = (ω ₀ / ν) ^1/2 x ν: Kinematic viscosity coefficient The following assumption was made.

U _r = ω ₀ rF (λ) uψ = ω ₀ rG (λ) u _x = (νω ₀ ) ^1/2 H (λ) P ′ = ηω ₀ K (λ) Is obtained.

[0044]

(Equation 15)

By substituting these into the equations (4) to (7), the simplification can be made as follows.

F ² + HF′−G ² −F ″ = 0 (8) 2FG + HG′−G ″ = 0 (9) HH ′ + K′−H ″ = 0 (10) 2F + H ′ = 0 (11) From the above boundary conditions, the boundary conditions in the equations (8) to (11) are as follows.

H (0) = 0, F (0) = 0, G (0) = 1 F (∞) = 0, G (∞) = 0, K (∞) = 0 Here, equation (10) Can be easily integrated, yielding the following equation:

[0048]

K = − [2F + (１ ／) H ² ] However, equations (8), (9) and (11) must be solved simultaneously as a simultaneous system.

Cochran solves this by series expansion. The results are shown in the graph of FIG.

If the value of λ, that is, the rotation speed ω ₀ , the kinematic viscosity coefficient ν, and the height x from the wafer are known, G,
The values of H and F are obtained. Substituting this into assumed equation of Von Karman, air velocity, u _r, uψ, u _x is determined.

When the wind speed distribution is calculated using the method described above, the results shown in FIGS. FIG. 15 shows the circumferential wind speed of an 8-inch φ wafer. The air in contact with the wafer moves at the same speed as the wafer, decelerates abruptly when leaving the wafer, and the wind speed approaches “0” at a point 1 mm above the wafer.

FIG. 16 shows the wind speed in the radial direction. In this case, the air is accelerated by the centrifugal force and reaches a maximum around 0.2 mm above the wafer, and approaches "0" at a point 1 mm above the wafer.

15 and 16, the turbulent flow is 1 mm above the wafer.
It can be seen that it occurs in the following areas.

FIG. 17 is a graph showing the relationship between the Reynolds number and the distance from the center of the wafer.

As described above, the Reynolds number is 2.35 × 1
0 ⁵ has been found that it is necessary to provide more than the a position.

Incidentally, turbulence occurs when the gradient of the wind speed distribution is large. Therefore, in order to reduce the inclination of this distribution, a disk-shaped plate is arranged above the wafer and rotated in the same direction as the wafer. If a disk-shaped plate is rotated above the wafer, an air flow is generated by the plate as in the case of the wafer. If the rotation direction of the plate is the same as that of the wafer, the gradient of the wind speed distribution becomes small, and the generation of turbulence is suppressed.

(Operation of the Invention of Claim 3 ) The turbulent flow generation region can be predicted by the Reynolds number (Re). In the case of a spin coating apparatus, according to experiments, Re = 2.3.
Turbulence occurs at 5 × 10 ⁵ . (The turbulent transition of air is generally 3.2 × 10 ^5. ) The Reynolds number is generally expressed by the following equation in the case of a rotating body.

[0058]

Re = ρr ² ω / η = r ² ω / ν Re: Reynolds number ρ: Density η: Viscosity coefficient ν: Kinematic viscosity coefficient r: Distance from the center of rotation ω: Angular velocity According to experiments, Reynolds number Turbulence does not occur if it is 2.35 × 10 ⁵ or less. Therefore, the required kinematic viscosity coefficient of the gas in the coating atmosphere is obtained by the following equation.

[0059]

(Equation 18) That is, turbulence is less likely to occur as the kinematic viscosity coefficient increases. Therefore, the inventor calculated how much the difference actually depends on the type of gas. The graph is shown in FIG.
FIG. 19 shows a case where a semiconductor substrate having a diameter of 200 mm (commonly called an 8-inch φ wafer) is rotated. When the atmosphere is air, increasing the rotation speed to 4000 r / min
The Reynolds number exceeds 2.35 × 10 ⁵ and turbulence occurs. However, in a Ne atmosphere, the Reynolds number is 2.35 × 10 ⁵ or less even when the rotation speed is increased to 8000 r / min, and it is understood that turbulence does not occur. Further, He,
In the H atmosphere, 25000 r / min is possible.

Further, it was calculated how large the size could be made by spin coating. FIG. 20 shows the result in the He atmosphere.

As shown in FIG. 20, one having a diameter of about 500 mm
It can be seen that spin coating can be performed at 000 r / min.

As described above, the Reynolds number can be reduced by filling the coating atmosphere with a gas having a high kinematic viscosity coefficient. The kinematic viscosity coefficients of the gas studied this time are as follows.

Air: 1.51 × 10 ⁻⁵ m ² / s Ne: 3.69 × 10 ⁻⁵ m ² / s He: 1.10 × 10 ⁻⁴ m ² / s H: 1.05 × 10 ^{− 4} m ² / s (20 ° C., 1 atm) By the way, many gases used in the present invention are expensive.
Therefore, the size of the region filled with the gas having a high kinematic viscosity coefficient, that is, the amount of gas used becomes a problem. Therefore, the wind speed distribution above the wafer when the above gas was used was calculated. By this calculation, a turbulence generation region, that is, a region to be filled with a high kinematic viscosity coefficient can be found. The calculation result will be described below.

As the wafer rotates, a gas flows above the wafer. Von Kar
It was calculated using the method of man and Cochran. The results are shown in FIGS. FIG. 21 shows the circumferential wind speed at 8 inches φ. The gas in contact with the wafer moves at the same speed as the wafer, and rapidly decelerates away from the wafer. The degree of this deceleration differs depending on the gas. The higher the kinematic viscosity coefficient, the slower the degree of deceleration. For example, in the case of air, the wind speed decreases to 0.2 m / s at the position of 0.7 mm above the wafer, whereas in the He atmosphere, the wind speed becomes 0.2 m / s at the position of 1.8 mm.

FIG. 22 shows the wind speed in the radial direction. In this case, the gas is accelerated by centrifugal force, and the manner of this acceleration differs depending on the gas. For example, in the case of air, the wind speed is maximum (7.9 m /
s), and decreases to 1 m / s at a position of about 0.8 mm. On the other hand, when the atmosphere is filled with He, height 0.5
The maximum wind speed is at the position of 2 mm and 1 m at the position of 2 mm or more.
/ S. As described above, it can be seen that the gas flow is generated in a region having a height of 2 mm or less above the wafer. That is,
It can be seen that the area to be filled with the gas having a high kinematic viscosity in the present invention is about 2 mm above the wafer.

[0066] Reynolds number, which is an indicator of the turbulent flow generating <Relationship Reynolds number and pressure> (claim 4 effects of the invention described) is defined in the case of a disc following equation rotates.

[0067]

Re = ρr ² ω / η = r ² ω / ν (a) Re: Reynolds number ρ: density η: viscosity coefficient ν: kinematic viscosity coefficient r: distance from the center of rotation ω: angular velocity The viscosity coefficient η hardly changes from several tens Pa to several atmospheres. On the other hand, the density changes depending on the atmospheric pressure, and the change is obtained by the following equation.

[0068]

(Equation 20)

P: Atmospheric pressure (mmHg) t: Temperature (° C.) The relationship between Reynolds number and atmospheric pressure can be obtained from the above equations (a) and (b).

FIG. 26 is a graph showing this relationship. FIG. 26 shows the Reynolds number when an 8-inch φ wafer is rotated at 4000 r / min. It can be seen that the Reynolds number decreases as the pressure decreases.

<Wafer diameter, rotation speed, and Reynolds under reduced pressure
Distance from the center of rotation when lowered's number> pressure, i.e. the wafer radius and Reynolds number relationship shown in FIG. 27. The rotation speed is 40
00 r / min.

If the pressure is reduced to 10,000 Pa (about 0.1 atm), a wafer having a diameter of 0.5 m can be spin-coated.

Next, the rotation speed when the pressure is reduced
FIG. 28 shows the relationship between the Reynolds numbers. The wafer diameter is 8 inches φ.

50,000 Pa (0.5 atm) from FIG.
If the pressure is reduced to 6000 r / min, the coating can be performed at a rotation speed of 6000 r / min or more. Furthermore, if the pressure is reduced to 2000 Pa (0.2 atm), spin coating at 12000 r / min or more becomes possible.

<How to determine the range of atmospheric pressure> The turbulent flow generation region can be predicted by the Reynolds number (Re). In the case of a spin coating device, according to experiments, Re = 2.3.
Turbulence occurs at 5 × 10 ⁵ . (The turbulence transition of air is generally 3.2 × 10 ^5. ) The Reynolds number is generally represented by the following equation in the case of a rotating body.

[0076]

Re = ρr ² ω / η = r ² ω / ν (c) According to the experiment, no turbulence occurs if the Reynolds number is 2.35 × 10 ⁵ or less. Therefore, the required kinematic viscosity coefficient of the gas in the coating atmosphere is obtained by the following equation.

[0077]

Ν = η / ρ ≧ r ² ω / Re ≧ r ² ω / 2.35
× 10 ⁵ (d) Here, the viscosity coefficient η hardly changes from several tens Pa to several atmospheres, and η = 1.830 × 10 ^-5
Pa · s. On the other hand, the density ρ is given by the following equation.

[0078]

(Equation 23)

When the equation (e) is substituted into the equation (d), the range of the atmospheric pressure is obtained.

[0080]

(Equation 24)

<How to determine the area to be decompressed (the size of the decompression chamber)> The decompression chamber is preferably as small as possible. This is because the target pressure can be reached in a short time, and the capacity of the pump can be small. It is economically advantageous as well as throughput.

Therefore, the wind speed distribution above the wafer when the atmosphere was reduced in pressure was calculated. By this calculation, the area to be decompressed is known. The calculation result will be described below.

As the wafer rotates, a gas flows above the wafer. Von Kar
It was calculated using the method of man and Cochran. The results are shown in FIGS. FIG. 29 shows the circumferential wind speed at 8 inches φ. The gas in contact with the wafer moves at the same speed as the wafer, and rapidly decelerates away from the wafer. The degree of this deceleration differs depending on the gas, and the lower the air pressure, the slower the degree of deceleration. And the area where air moves is also expanding.

For example, at 101325 Pa (1 atm),
At a height of 0.7 mm above the wafer, the wind speed drops to 2.0 m / s, whereas at 10,000 Pa (about 0.1 atm), the wind speed becomes 2.0 m / s at a height of 2.4 mm. .

FIG. 30 shows the wind speed in the radial direction. In this case, the gas is accelerated by centrifugal force, and the manner of this acceleration differs depending on the gas. For example, 101325
At Pa (1 atm), the wind speed reaches a maximum (7.9 m / s) at a height of 0.2 mm above the wafer and drops to 1 m / s at a position of about 0.8 mm. On the other hand, the atmosphere is 10,000P
a (approximately 0.1 atm), height 0.6mm
The wind speed becomes maximum at the position of 1m / s at the position of 2mm or more.
To decline.

As described above, the present inventor has determined that
It has been clarified that the gas flow under a reduced pressure (about 0.1 atm) is generated in a region having a height of 2 mm or less above the wafer.
The pressure that is actually considered necessary is 10,000 Pa
(0.1 atm), indicating that the area to be decompressed in the present invention may be about 2 mm above the wafer.

(Functions of the Invention Other Than Claims 1 to 4 ) A chuck for holding a substrate and the chuck
And a rotating means for rotating the substrate.
The rack is held and rotated in a horizontal plane,
A resist for applying a resist dropped on a substrate to the upper surface of the substrate.
In the spin coating method, the radius of the substrate is r,
Assuming that the angular velocity of the substrate is ω, the coating atmosphere of the substrate is
Expression,

[0088]

(Equation 25)  t (° C) ≧ √ (1800 + 30000r ^Two ω) -314.2 Characterized in that the temperature is higher than the temperature t represented by
In the case of the spin coating method, the action is as shown below.
You.

<Relationship between Reynolds Number and Temperature> The Reynolds number, which is an index of turbulence generation, is defined by the following equation in the case of a rotating disk.

[0090]

Re = ρr ² ω / η = r ² ω / ν (f) Re: Reynolds number ρ: density η: viscosity coefficient ν: kinematic viscosity coefficient r: distance from the center of rotation ω: angular velocity Here, air Varies with temperature, and the change is given by the following equation.

[0091]

Η = η ₀ −4.83 × 10 ⁻⁸ (23−t) (Pa, s) (g) η ₀ : viscosity coefficient at 23 ° C. Density ρ also changes with temperature. The change is determined by the following equation.

[0092]

[Equation 28]

From equations (f), (g) and (h), Reynolds
Relationship's number and the temperature is obtained.

FIG. 33 is a graph showing this relationship. FIG. 33 shows the Reynolds number when an 8-inch φ wafer is rotated at 4000 r / min. It can be seen that the Reynolds number decreases as the temperature decreases.

<Wafer diameter, rotation speed and Reynolds under temperature
Distance from the center of rotation when raised's number> temperature, i.e. the wafer radius and Reynolds number relationship shown in FIG. 34. The rotation speed is 40
00 r / min. If the temperature is raised to 60 ° C., spin coating of an 8 inch φ wafer at 4000 r / min becomes possible.

Next, the number of rotations when the temperature is increased and
FIG. 35 shows the relationship between the Reynolds numbers. The wafer diameter is 8 inches φ.

From FIG. 35, if the temperature is increased to 100 ° C., 5
The coating can be performed at a rotation speed of 000 r / min or more. Furthermore, if the temperature is raised to 250 ° C., 10,000 r / min
The above spin coating can be performed.

<Method of Determining Temperature Range> The turbulent flow generation region can be predicted by the Reynolds number (Re). In the case of a spin coating apparatus, according to experiments, Re = 2.3.
Turbulence occurs at 5 × 10 ⁵ . (The turbulence transition of air is generally 3.2 × 10 ^5. ) The Reynolds number is generally represented by the following equation in the case of a rotating body.

[0099]

Re = ρr ² ω / η = r ² ω / ν (i) According to the experiment, no turbulent flow occurs if the Reynolds number is 2.35 × 10 ⁵ or less. Therefore, the required kinematic viscosity coefficient of the gas in the coating atmosphere is obtained by the following equation.

[0100]

Ν = η / ρ ≧ r ² ω / Re ≧ r ² ω / 2.35 × 10 ⁵ (m ² / s) (j) Generally, the viscosity coefficient η changes with temperature, and the change is It is given by the following equation.

[0101]

Η = η ₀ −4.83 × 10 ⁻⁸ (23−t) (Pa · s) (k) Further, the density ρ also changes with temperature, and the change is expressed by the following equation. You.

[0102]

(Equation 32)

By substituting the expressions (k) and (l) into the expression (j), the following expression is obtained.

[0104]

[Equation 33]

Here, since η ₀ = 1.83 × 10 ⁻⁵ , the following quadratic equation can be obtained by substituting into equation (m).

[0106]

(Equation 34)

By solving the equation (n), the range of the temperature is obtained.

[0108]

(35) t ≧ ８００ (1800 + 31038r ² ω) -314,2 (° C.) (o) For example, when it is desired to spin-coat an 8 ″ wafer at 4000 r / min, the atmosphere is set to 48.9 ° C. or more according to the formula (o). It turns out that it is good to do.

<Area to be heated (chamber size)
How to determine> The smaller the chamber is, the better. This is because the target temperature can be reached in a short time, which is advantageous in terms of economy and throughput. Therefore, the wind speed distribution above the wafer when the temperature was increased was calculated. By this calculation, the region where the temperature should be raised can be determined. The calculation result will be described below.

As the wafer rotates, a gas flows above the wafer. Von Kar
It was calculated using the method of man and Cochran. The results are shown in FIGS. FIG. 36 shows the circumferential wind speed at 8 inches φ. The gas in contact with the wafer moves at the same speed as the wafer, and rapidly decelerates when the gas leaves the wafer. The degree of the deceleration differs depending on the temperature, and the higher the temperature, the less the degree of the deceleration. And the area where air moves is also expanding.

For example, at 20 ° C., the height above the wafer is 0.7 m
m, the wind speed drops to 0.2 m / s, while 3
At 00 ° C., the wind speed is 0.2 m / s at a height of 1.4 mm.
become.

FIG. 37 shows the wind speed in the radial direction. In this case, the gas is accelerated by centrifugal force, and the manner of this acceleration differs depending on the temperature. For example, at 20 ° C,
The wind speed is maximum (7.9 m) at a height of 0.2 mm above the wafer.
/ S), and decreases to 1 m / s at a position of about 0.8 mm. On the other hand, when the atmosphere is set to 300 ° C., the height is 0.3
The maximum wind speed is reached at a position of 5 mm, and decreases to 1 m / s at a position of 1.4 mm or more.

As described above, the present inventor has clarified that the gas flow in the atmosphere at 300 ° C. is generated in a region having a height of 1.4 mm or less above the wafer. Further, it is understood that the temperature actually considered necessary is about 300 ° C., and the area to be heated in the present invention may be about 2 mm on the wafer.

[0114]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a resist coating apparatus according to the present invention will be described below based on embodiments shown in the drawings.

Example 1 FIG. 1 is a schematic side view of the present example, and FIG. 2 is a perspective view.

First, the wafer 11 is placed on the wafer chuck 10, and a disk 13 rotated and driven by a motor 12 is arranged above the wafer 11 in parallel and coaxially with the wafer 11. In this embodiment, the wafer 11 and the disk 1
3 was set to 0.5 mm. The disk 13
The rotation direction and the number of rotations were the same as the rotation direction and the number of rotations of the wafer 11.

As a result, in an 8-inch wafer, 4
Even at 000 r / min or more, turbulence does not occur, film thickness non-uniformity is suppressed, and film thickness uniformity has a fluctuation width of 4.0 nm (40 °).
was gotten.

(Embodiment 2) The configuration of a resist coating apparatus according to this embodiment is the same as that of the above embodiment, except that the rotation speed of the disk 13 is lower than the rotation speed of the wafer 11 within the range of the following equation.

[0119]

| Ω ₁ −ω ₂ | = (ν / r ₀ ² ) × 2.15 × 10 ⁵ For example, for an 8-inch φ wafer, 6000 r / mi
n, the rotational speed of the disc 13 is set to 2610
r / min. At this time, no unevenness in the thickness of the resist was generated, and the thickness uniformity variation range (Range) = 4.0.
nm was obtained.

The rotational speed of the disk was calculated assuming that the kinematic viscosity coefficient ν of air was 1.57 × 10 ⁻⁵ m ² / s.

(Embodiment 3) In the resist coating apparatus according to the present embodiment, the disk 13 can be moved so as to be positioned above the wafer 11 only when the wafer 11 is rotated, in the configuration of the above-mentioned Embodiment 1. It was done. The application of the resist is performed under an environment where the temperature and the humidity are controlled. Therefore, the retention of air should be minimized. On the other hand, if the disk 13 is always arranged above the wafer 11, there is a possibility that air may stay. Therefore, in this embodiment, the disk 13 is made movable and can be arranged only when the wafer is rotating.

FIG. 3 is an explanatory view of a resist coating apparatus according to the present embodiment, and FIG. 4 is a side view showing a procedure of resist coating using the present apparatus. In FIG. 3, reference numeral 18 denotes a processing cup, which is a container for collecting excess resist scattered when the wafer 11 rotates. Also, as shown in FIG.
The motor 12 to which the motor 1 is connected is connected to a driving unit 17 via an arm 16, and the driving unit 17
The disk 13 can be moved to the upper position and the standby position.

Next, a resist coating process using the present apparatus will be described with reference to FIG.

First, as shown in FIG.
1 is held on the wafer chuck 10 and the resist 14 is discharged from the resist discharge nozzle 15. At this time, disk 1
Reference numeral 3 denotes a standby position that is far from the wafer 11 so as not to affect the resist coating atmosphere.

Next, when the resist discharge is completed, FIG.
As shown in (B), the disk 13 is moved above the wafer 11 by the driving means 17, and simultaneously with the rotation of the wafer 11, the motor 12 is driven to rotate the disk 13. At this time, the distance between the wafer 11 and the disk 13 was set to 1 mm or less.

According to the present embodiment, 4 inches for an 8-inch φ wafer
No turbulence was observed even under the condition of 000 r / min.
The in-plane uniformity was a fluctuation width of 3.5 nm. This embodiment is particularly effective for the stability of the film thickness, and uniformity of the fluctuation width of the entire resist film = 4.0 nm was obtained.

(Embodiment 4) For the above-mentioned reason, it is desirable that the shape of the disk is such that air does not easily stay. Furthermore, the turbulent flow has a Reynolds number of 2.35 ×
Occurs in more than 10 ⁵ regions. Therefore, the disc 13A was made into a donut shape.

FIG. 5 is an explanatory view of this embodiment, and FIG.
Are shown below. In the figure, reference numeral 18 denotes the disk 13A
Shows the support connected to.

[0129] The disk 13A has a cavity near the center, so that it is difficult for air to stay. The position and width of the ring-shaped (doughnut-shaped) disk 13A are obtained by the following equations.

Distance r of disk 13A from wafer center

[0131]

R = √ (Reν / ω) Ring width w

[0132]

W = r ₀ −√ (Reν / ω) Reynolds number Re Re = 2.35 × 10 ⁵ Kinematic viscosity coefficient ν ν = 1.57 × 10 ⁻⁵ m ² / s For example, an 8-inch φ wafer is 6000r. When spinning at a rate of / min, the donut-shaped disc should have a width of 25 mm covering the center from 75 mm to 100 mm. Even at 6000 r / min, no film thickness unevenness occurred.

At this time, the uniformity of the film thickness is determined by the variation width of the film thickness =
It was 3.5 nm. This embodiment is particularly effective for the film thickness stability, and uniformity with a total film thickness variation width of 4.0 nm was obtained.

(Embodiment 5) For the reasons described above, it is preferable that the width of the disk 13A is as narrow as possible. Therefore, the width of the donut-shaped disk is controlled so as to be the minimum width.

For example, a donut-shaped disc is made into a diaphragm shape of a camera, the number of rotations of the wafer is detected, and the width of the disc is controlled based on the data based on the following equation.

[0136]

W = r ₀ −√ (Reν / ω ₁ ) (Embodiment 6) From the above calculation results, the present inventor has found that the ring-shaped disc 1
3A found that the distance above the wafer had to be within 1 mm.

It has also been found that it is necessary to provide a position where the Reynolds number is 2.35 × 10 ⁵ or more. Therefore,
The distance and the width of the ring-shaped disc 13A from the center of the wafer can be obtained by the following equations.

The distance r from the center of the ring

[0139]

R = √ (Reν / ω) Ring width w

[0140]

W = r ₀ −√ (Reν / ω) Reynolds Number Re Re = 2.35 × 10 ⁵ Kinematic Viscosity Coefficient ν ν = 1.57 × 10 ⁻⁵ m ² / s FIG. As shown in FIG. As shown in FIG. 7, a ring-shaped disk 13A was provided above the wafer 11. FIG. 8 is a perspective view. The present embodiment is an 8 inch φ wafer compatible machine. The specific dimensions are 83 mm to 100 m from the center of the wafer 11 when applying at a rotation speed of 5000 r / min.
A ring-shaped disk 13A having a width of 17 mm was provided at a position of m and a height of 0.5 mm.

As a result, even when the number of revolutions of the 8-inch φ wafer 11 was increased to 5000 r / min, there was no unevenness in the film thickness of the resist, and a film thickness uniformity of 4 nm (40 °) was obtained with a variation width.

(Embodiment 7) In the present embodiment, a machine corresponding to a 12-inch φ wafer was specifically set as follows.

A ring-shaped disk 13 having a width of 67 mm is placed at a position of 83 mm to 150 mm and a height of 0.5 mm from the center of the wafer.
A was provided.

Even when the number of revolutions was increased to 5000 r / min, no film thickness unevenness due to turbulence occurred. Disk 13A
In the case where there was no, the rotation speed could be increased only up to 1600 r / min, and the uniformity of the film thickness was changed by 8 n
m (80 °), but in this embodiment, the fluctuation width = 4n
m (40 °) uniformity was obtained.

(Embodiment 8) In this embodiment, the following structure was adopted for an 8 inch φ wafer in order to cope with high-speed rotation.

65 mm to 100 m from center of wafer 11
A ring-shaped disk 13A having a width of 35 mm was provided at a position of m and a height of 0.5 mm.

As a result, even when the number of revolutions was increased to 8000 r / min, no unevenness in film thickness due to turbulence was observed, and the variation in film thickness uniformity was 3.5 nm (35 °).

(Embodiment 9) The resist is applied in an atmosphere in which the temperature and the humidity are controlled. Therefore, it is better that the area where air stays on the wafer is small. On the other hand, the ring-shaped disc 13A of this embodiment
May cause air stagnation. Therefore, the disk 13
A was placed above the wafer only when the wafer with A movable was rotating. Specifically, the structure is as shown in FIG.

As shown in the figure, a ring-shaped disk 13A
Is held by the arm 16 and moved by the driving means 17.

The operation will be described with reference to FIG.

First, the resist 14 is discharged from the resist discharge nozzle 15 (FIG. 10A). At this time, the disk 13
A is located at a distance such that the air above the wafer 11 is not retained. Next, the disk 13A is moved above the wafer 11 by the driving means 17 (FIG. 10B). afterwards,
Before or at the same time as the rotation of the wafer 11, the turbulence of air due to the rotation of the wafer 11 is suppressed by approaching to a height of 0.5 mm above the wafer 11.

Since the stagnation of air was reduced by this embodiment, the stability between wafers and between lots was particularly improved.
A film thickness uniformity of in-plane film thickness fluctuation width = 4.0 nm (40 °) was obtained.

(Embodiment 10) For the above reason, it is preferable that the width of the ring-shaped disc 13A is as narrow as possible. On the other hand, the distance of the ring-shaped disk 13A from the center of the wafer is determined by the number of rotations.

[0154]

R = √ (Reν / ω) r: distance from the center of the wafer That is, in this embodiment, the width of the ring-shaped disk 13A can be controlled to be the minimum width based on the number of rotations. is there. FIG. 11 is an explanatory diagram of this embodiment. The width of the disk 13A is variable like an aperture of a camera. The width is controlled by the ring width controller 20. The ring width control device 20 detects the rotation speed (angular velocity ω) of the motor 19 and detects the minimum width of the ring based on the above equation. The ring diameter driving means 21 controls the width of the disc 13A based on this value.

According to this example, the in-plane variation width of the film thickness uniformity was 4.0 nm (40 °).

(Embodiment 11) In this embodiment, as shown in FIG. 12, the cross-sectional shape of the disk 13A was made to be streamlined so that the disk 13A did not cause turbulence.

According to the present example, the generation of turbulence was further suppressed, and the variation in film thickness uniformity was 3.5 nm.

While the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various design changes accompanying the gist of the configuration are possible.

Embodiment 12 FIG. 14 shows the configuration of a coating apparatus used in this embodiment. FIG.
Reference numeral 8 denotes a coating apparatus for performing spin coating in a Ne atmosphere, and the wafer size to be processed is 8 inches. Cup 20 is N
e is sealed by the lid 21 so as to satisfy e. The temperature of the Ne gas sent therein is controlled by the gas temperature controller 22. Further, the entire cup 20 is covered with a hood 23, and the entire temperature is controlled by an atmosphere temperature controller 24. In the figure, 25 is a discharge nozzle,
26 is a wafer chuck, 27 is a wafer, 28 is a hepa filter, 29 is a heat exchanger, and 30 is a Ne gas cylinder.

Next, the operation will be described.

1) The temperature and humidity of the resist coating atmosphere are controlled to 23 ° C. and 40% by the atmosphere temperature controller 24.

2) The wafer 27 is transferred onto the wafer chuck 26 and held.

3) The lid 21 is in close contact with the cup 20, and the resist coating atmosphere is closed.

4) Ne gas is sent from the Ne gas cylinder 30 into the cup 20, and the coating atmosphere is filled with Ne.
At this time, the temperature of the Ne gas is controlled to 23 ° C. by the temperature controller 22.

5) The resist is discharged from the nozzle 25.

6) The wafer is rotated, and a resist film is formed. At this time, since the atmosphere is Ne, the Reynolds number can be suppressed to 2.35 × 10 ⁵ or less.

7) After stopping the rotation, the lid 21 comes off and the wafer 2
7 is carried out.

Resist on 8 inch φ wafer, TSMR-
As a result of applying 8900 (manufactured by Tokyo Ohka), 8000 r /
No film thickness unevenness due to turbulence was observed up to min. The film thickness uniformity at this time was Range = 4.0 nm.

Example 13 The Ne gas in FIG. 18 was changed to He gas, and a resist was applied. In the case of He, film thickness unevenness does not occur up to 25000 r / min, and film thickness uniformity is Range = 3.5 nm.
was gotten.

(Embodiment 14) This embodiment is an example in which the same effect can be obtained by using a mixed gas of Ne and He. When the resist was applied at a mixture ratio of Ne: He = 1: 2, 15000 r / min was obtained.
Uneven film thickness due to turbulence was not observed, and the film thickness uniformity was Ra
nge = 3.8 nm was obtained.

[0171] Although the same effect as that of Ne gas can be obtained by using H gas and a mixed gas thereof, there is a risk of explosion and there is a problem in safety.

(Embodiment 15) Ne gas, He gas and the like are expensive. For example, Ne gas is about 10,000 yen / 10 l. Therefore, it is necessary to suppress the usage as much as possible.

On the other hand, it was expected that the area filled with this gas should be about 2 mm above the wafer as described in the above operation. Therefore, the lid 21 in FIG.
m. FIG. 23 shows a configuration diagram thereof.

FIG. 23 shows a coating apparatus for performing spin coating in a Ne atmosphere, and the wafer size to be processed is 8 inches.
The cup 20 has a lid 21 so that Ne can be filled.
Sealed. The temperature of the Ne gas sent therein is controlled by the temperature controller 22. Further, the entire cup 20 is covered with a hood 23, and the entire temperature is controlled by an atmosphere temperature controller 24.

Next, the operation will be described.

1) The resist coating atmosphere temperature and humidity are controlled to 23 ° C. and 40% by an atmosphere temperature controller 24.

2) The wafer 27 is transferred onto the wafer chuck 26 and held.

3) The lid 21 approaches the wafer up to 2 mm,
The resist coating atmosphere is tightly closed in close contact with the cup 20.

4) Ne gas is sent from the Ne gas cylinder 30 into the cup 20, and the coating atmosphere is filled with Ne.
At this time, the temperature of the Ne gas is controlled to 23 ° C. by the temperature controller 22.

5) The resist is discharged from the nozzle 25.

6) The wafer is rotated, and a resist film is formed. At this time, since the atmosphere is Ne, the Reynolds number can be suppressed to 2.35 × 10 ⁵ or less.

7) After stopping the rotation, the lid 21 comes off and the wafer 2
7 is carried out.

Resist on 8 inch φ wafer, TSMR-
As a result of applying 8900 (manufactured by Tokyo Ohka), 8000 r /
No film thickness unevenness due to turbulence was observed up to min. The film thickness uniformity at this time was Range = 4.0 nm.

The amount of the Ne gas used was 2 l per wafer in the prior art, but has been improved to 0.7 l in the present embodiment.

Embodiment 16 FIG. 24 shows a coating apparatus used in this embodiment. FIG.
The size of a wafer to be processed is 8 inches in a coating apparatus that performs spin coating under reduced pressure. The cup 20 can be closed by a lid 21. When the wafer is carried,
At the time of discharging the resist, it escapes. Cup 2
A rotary pump 31 having an output of 500 W is connected to 0, and reaches 10,000 Pa (about 0.1 atm) in about 3 seconds.

The entire cup 20 is covered with a hood 23, and the whole temperature is controlled by an atmosphere temperature controller 24. The air mixed into the resist has been removed in advance using ultrasonic waves.

Next, the operation will be described.

1) The temperature and humidity of the resist application atmosphere are controlled at 23 ° C. and 40% by the atmosphere temperature controller 24.

2) The wafer 27 is transferred onto the wafer chuck 26 and held.

3) The resist is discharged from the nozzle 25.

4) The lid 21 is in close contact with the cup 20, and the resist coating atmosphere is closed.

5) Cup 2 by rotary pump 3
Within 0, the coating atmosphere is reduced to 10,000 Pa (0.1 atm).

6) The wafer is rotated, and a resist film is formed. At this time, since the pressure is under reduced pressure, the Reynolds number is suppressed to 2.35 × 10 ⁵ or less.

7) After the rotation is stopped, the lid 21 comes off and the wafer 2
7 is carried out.

Resist on 8 inch φ wafer, TSMR-
As a result of applying 8900 (manufactured by Tokyo Ohka), no film thickness unevenness due to turbulent flow was observed up to a wafer rotation speed of 12000 r / min. The film thickness uniformity at this time is Ran
ge = 4.0 nm was obtained.

Example 17 In FIG. 24, the pressure in the cup 20 was set to 5000 Pa.
(0.5 atm). As a result, the time required for decompression could be reduced from 3 seconds to 1 second. At this time, when the resist TSMR-8900 was applied to the 8-inch φ wafer, the film thickness non-uniformity due to turbulence did not occur up to a rotation speed of 6500 r / min, and a film thickness uniformity of Range = 4.5 nm was obtained.

(Embodiment 18) The smaller the size of the chamber and cup 20 for reducing the pressure, the shorter the time required for the pressure reduction, which is economically advantageous in terms of throughput. Then, the lid of the cup was brought close to 2 mm based on the calculation result of the above-mentioned action. FIG. 25 shows a configuration diagram thereof.

The operation is the same as that of (Embodiment 16), except that the lid 21 approaches the wafer 27 by 2 mm. Thereby, the time to reach the reduced pressure (10000 Pa) could be reduced to 0.5 seconds. At this time, the film thickness unevenness due to turbulence is 12000.
r / min was not observed, and a film thickness uniformity of Range = 4.0 nm was obtained under the same conditions as above.

Example 19 In FIG. 25, the pressure of the coating atmosphere was 50,000 Pa.
(0.5 atm). Combined with the effect of the lid 21 approaching 2 mm, the time required for pressure reduction was reduced to 0.1 second.

At this time, the film thickness unevenness due to turbulence was 6500
r / min does not occur, and the film thickness uniformity is Range =
4.5 nm was obtained.

(Embodiment 20) FIG. 31 shows the configuration of a coating apparatus used in this embodiment.

FIG. 31 shows a coating apparatus for performing spin coating at a high temperature, and the wafer size to be processed is 8 inches. The cup 20 can be closed by a lid 21. The lid 21 is designed to escape during wafer transfer and resist discharge. A 1 kW heater 32 is connected to the cup 20 and reaches 300 ° C. in about 3 seconds.

The entire cup 20 is covered with a hood 23, and the whole temperature is controlled by an atmosphere temperature controller 24. The air mixed into the resist has been removed in advance using ultrasonic waves.

Next, the operation will be described.

1) The temperature and humidity of the resist coating atmosphere are controlled at 23 ° C. and 40% by an atmosphere temperature controller 24.

2) The wafer 27 is transferred to and held on the wafer chuck 26.

3) The resist is discharged from the nozzle 25.

4) The lid 21 is in close contact with the cup 20, and the resist coating atmosphere is closed.

5) Inside the cup 20 by the heater 32, 3
Air at 00 ° C. is supplied.

6) The wafer 27 rotates, and a resist film is formed. At this time, since the temperature is high, the Reynolds number is suppressed to 2.35 × 10 ⁵ or less.

7) After the rotation is stopped, the lid 21 comes off and the wafer 2
7 is carried out.

Resist on 8 inch φ wafer, TSMR-
As a result of applying 8900 (manufactured by Tokyo Ohka), no film thickness unevenness due to turbulence was observed up to a wafer rotation speed of 10,000 r / min. The film thickness uniformity at this time is Ran
ge = 4.0 nm was obtained.

Example 21 In FIG. 31, the temperature inside the cup 20 was set to 60 ° C. This allows the time to reach the target temperature from 3 seconds to 1
Seconds. At this time, when the resist TSMR-8900 was applied to the 8-inch wafer, the number of rotations was 400.
No film thickness unevenness due to turbulence occurs up to 0 r / min
A film thickness uniformity of ge = 4.5 nm was obtained.

Embodiment 22 The smaller the size of the chamber and cup 20 to be heated, the shorter the time required to reach the target temperature, which is economically advantageous in terms of throughput. Then, the lid of the cup was brought close to 2 mm based on the calculation result of the above-mentioned action. The configuration diagram is shown in FIG.

The operation is the same as that in (Embodiment 20), except that the lid 21 approaches the wafer 27 by 2 mm. Thereby, the time to reach 300 ° C. could be reduced to 0.5 seconds. At this time, film thickness unevenness due to turbulence was not observed up to 10,000 r / min.
4.0 nm was obtained.

Example 23 In FIG. 32, the temperature of the coating atmosphere was set to 60 ° C.
Combined with the effect of the lid 21 approaching 2 mm, the time required for the target temperature was reduced to 0.1 second. At this time, the thickness unevenness due to the turbulence does not occur up to 4000 r / min.
As for the film thickness uniformity, Range = 4.5 nm was obtained.

Although the embodiments have been described above, each invention is not limited to this, and various design changes and conditions can be changed accompanying the gist of the configuration.

[0219]

As is apparent from the above description, according to the present invention, it is possible to suppress the occurrence of turbulent flow due to high-speed rotation in the resist spin coating method, and thus the uniformity of the resist film thickness caused by the turbulent flow. Has the effect of suppressing the deterioration of In particular, there is an effect that a film thickness uniformity of ± 25 ° or less can be achieved.

According to the present invention, the Reynolds number is 2.3.
Resist coating at 5 × 10 ⁵ or more is possible, and there is an effect that high-speed rotation becomes possible. For example, it is possible to achieve a high speed of 4000 r / min or more for an 8-inch wafer and 1600 r / min for a 12-inch wafer.

Further, since the range of the number of rotations is widened, there is an effect that the range of the film thickness that can be achieved with one type of resist can be expanded.

Further, according to the third and fourth aspects of the present invention, there is an effect that the Reynolds number is particularly suppressed to 2.35 × 10 ⁵ or less.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a first embodiment of the present invention.

FIG. 2 is a perspective view of Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram of a third embodiment of the present invention.

FIG. 4 is an explanatory view of a process according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 6 is an explanatory view of Embodiment 4 of the present invention.

FIG. 7 is a sectional view of a sixth embodiment of the present invention.

FIG. 8 is a perspective view of a sixth embodiment of the present invention.

FIG. 9 is a sectional view of a ninth embodiment of the present invention.

FIG. 10 is an explanatory view of a step in Example 9 of the present invention.

FIG. 11 is an explanatory view of Embodiment 10 of the present invention.

FIG. 12 is a sectional view of an eleventh embodiment of the present invention.

FIG. 13 is a graph showing the relationship between Reynolds number and rotation speed.

FIG. 14 is a graph showing a velocity distribution near a rotating disk (wafer).

FIG. 15 is a graph showing the relationship between the height from an 8-inch φ wafer and the flow rate of air.

FIG. 16 is a graph showing a relationship between a wind speed in a radial direction and a height from a rotating disk (wafer).

FIG. 17 is a graph showing the relationship between the Reynolds number and the distance from the center of the wafer.

FIG. 18 is an explanatory view of Embodiment 12 of the present invention.

FIG. 19 is a graph showing the relationship between Reynolds number and rotation speed.

FIG. 20 is a graph showing the relationship between the Reynolds number and the distance from the center of the disk.

FIG. 21 is a graph showing the relationship between the height from an 8-inch φ wafer and the circumferential flow rate of atmospheric gas.

FIG. 22 is a graph showing a relationship between a height from an 8-inch φ wafer and a flow velocity of an atmospheric gas in a radial direction.

FIG. 23 is an explanatory view of a coating apparatus used in Embodiment 15 of the present invention.

FIG. 24 is an explanatory diagram of a coating apparatus used in Embodiment 16 of the present invention.

FIG. 25 is an explanatory view of a coating apparatus used in Embodiment 18 of the present invention.

FIG. 26 is a graph showing a relationship between Reynolds number and pressure when an 8-inch φ wafer is rotated at 4000 rpm.

FIG. 27 is a graph showing the relationship between the wafer radius (distance from the center of rotation) and the Reynolds number when the pressure is changed.

FIG. 28 is a graph showing the relationship between Reynolds number and rotation speed when the pressure is changed.

FIG. 29 is a graph showing the relationship between the height of an 8-inch φ wafer and the wind speed (flow velocity) in the circumferential direction.

FIG. 30 is a graph showing the relationship between the height and the wind velocity (flow velocity) in the radial direction on an 8-inch φ wafer.

FIG. 31 is an explanatory view of a coating apparatus used in Example 20 of the present description.

FIG. 32 is an explanatory view of a coating apparatus used in Embodiment 23 of the present invention.

FIG. 33 is a graph showing a relationship between Reynolds number and temperature when an 8-inch φ wafer is rotated at 4000 rpm.

FIG. 34 is a graph showing the relationship between the distance from the rotation center and the Reynolds number when the rotation speed is 4000 rpm.

FIG. 35 is a graph showing the relationship between the rotation speed and the Reynolds number when the temperature is changed.

FIG. 36 is a graph showing a relationship between an airflow (flow velocity) and a height in a circumferential direction on an 8-inch φ wafer.

FIG. 37 is a graph showing the relationship between the wind speed (flow velocity) and the height in the radial direction of an 8-inch φ wafer.

FIGS. 38A, 38B, and 38C are explanatory views of a coating process using a conventional resist coating device.

FIG. 39 is an explanatory diagram showing a relationship between a resist film thickness and a position due to turbulence in a conventional example.

[Explanation of symbols]

 10 chuck 11 wafer 12 motor 13 disk

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-245870 (JP, A) JP-A-3-245875 (JP, A) JP-A-2-219213 (JP, A) JP-A-62-1987 185321 (JP, A) JP-A-62-61670 (JP, A) JP-A-4-44216 (JP, A) JP-A-5-136041 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027

Claims (4)

(57) [Claims] 1. A chuck for holding a substrate, and at least rotating means for rotating the chuck, wherein the chuck is held on the chuck and rotated in a horizontal plane, whereby the substrate is dropped on the substrate. A resist coating apparatus for coating the resist on the upper surface of the substrate, wherein a ring-shaped plate is disposed close to and above the substrate held by the chuck and parallel to the substrate. The width (L) of the ring is expressed by the following equation with respect to the Reynolds number (Re), the radius of the substrate (r ₀ ), the kinematic viscosity coefficient of air (ν), and the angular velocity of the substrate (ω). , resist coating apparatus characterized by having a relationship of Equation 1] _{L = r 0 -√ (Reν /} ω). 2. An angular velocity (ω ₁ ) of the ring-shaped plate is expressed by the following equation with respect to an angular velocity (ω ₂ ) of the substrate, a radius (r ₀ ) of the substrate, and a kinematic viscosity coefficient of air. 2. The resist coating apparatus according to claim 1, wherein the rotation is performed while satisfying | ω ₁ −ω ₂ | ≦ (ν / r ₀ ² ) × 2.35 × 10 ⁵ . 3. A chuck for holding a substrate, and at least a rotating unit for rotating the chuck, wherein the chuck is rotated on a horizontal plane while the chuck is held on the chuck, whereby the substrate is dropped on the substrate. A spin coating method of coating the resist on the upper surface of the substrate, wherein a ring-shaped plate is disposed close to and above the substrate held by the chuck, and in parallel with the substrate; Where r is the angular velocity of the substrate and ω is the angular velocity of the substrate. A gas having a kinematic viscosity larger than the kinematic viscosity expressed by the following equation: ν ≧ r ² ω / 2.35 × 10 ⁻⁵ A method of spin-coating a resist, wherein the coating atmosphere of the substrate is satisfied. And a chuck for holding the substrate, and rotating means for rotating the chuck, wherein the chuck holds the substrate and rotates the chuck in a horizontal plane, thereby dropping the substrate on the substrate. In the method of spin-coating a resist, the resist is applied to the upper surface of the substrate, where r is the radius of the substrate, ω is the angular velocity of the substrate, and t is the temperature of the substrate. A spin coating method for a resist, wherein the pressure is smaller than a pressure P represented by the following formula: P (mmHg) ≦ 2.50 × 10 ³ × (1 + 0.00367 t) / r ² ω