JPH05283331A - Resist coating device and method for spin-coating with resist - Google Patents

Abstract

PURPOSE:To suppress the generation of turbulent flow caused by high-speed rotation in spin-coating, and to realize uniform thickness of resist. CONSTITUTION:While holding a wafer 11 with a wafer chuck 10, a circular plate 13, which is rotated by a motor 12, is disposed above the wafer 11, in parallel with the wafer 11 and nearby the wafer 11. The distance between the circular plate 13 and the wafer 11 is 0.5mm, and the number of rotations and the rotating direction of the circular plate 13 are the same as those of the wafer 11. In the case of a wafer of 8-inch diameter, turbulent flow does not generate even at a rotational speed of above 4,000r/min, and ununiformity of the film thickness can be suppressed. At this time, varying range of uniformity of the film thickness is 4.0nm (40Angstrom ). The number of rotations of the circular plate 13 can be lower than that of the wafer 11 within the range of ¦omega1-omega2¦=(nu/r0<2>)X2.15X10<5>.

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 turbulent flow during photoresist coating.

[0002]

2. Description of the Related Art In recent years, miniaturization of semiconductor devices has progressed, and accordingly, a highly accurate pattern forming technique has been required. The required accuracy is generally ± 10% of the design rule.
Is. For example, design rule 0.35μm ultra LS
In I, an accuracy of ± 0.035 μm (uniformity of pattern line width) is essential.

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

Considering such factors of line width variation, in a VLSI having a design rule of 0.35 μm, resist film thickness uniformity of 5 nm (50 Å) or less is required.

On the other hand, the diameter of the wafer is being increased in order to improve the productivity, and the diameter of the wafer is currently 200 m.
Those of m (8 inches) φ are becoming mainstream.

However, as the wafer diameter increases, it becomes more difficult to form a uniform resist film thickness. Since the coating area increases, it is natural that the uniformity deteriorates, but another cause is that the number of rotations during coating cannot be increased sufficiently. In order to explain this, first, a general coating process will be described with reference to FIG.

Generally, in applying a photoresist, the wafer 1 is first held on the wafer chuck 2 and then the resist 4 is discharged from the resist discharge nozzle 3 (FIG. 38 (A)). After that, the wafer 1 is rotated to form a resist film (FIGS. 38B and 38C). The resist film thickness is determined by the rotation speed and time at this time, and this rotation speed is generally 3000.
~ 6000 r / min.

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

[0009]

However, as the diameter of the wafer increases, the peripheral velocity also increases and air turbulence easily occurs. When turbulent flow occurs, the evaporation amount of the solvent of the resist locally changes and the film thickness greatly changes. This is 19
1990, Haruo Symbiosis Lecture Proceedings 28a-PD-14. According to it, 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 unevenness of the resist film thickness occurs around the wafer due to turbulent air flow.

In the experiment by the present inventor, the rotation speed was 3500 r
It has been confirmed that uniformity is good up to / min. 400
At 0 r / min, the turbulence of the resist film thickness caused by the turbulent flow from the wafer edge to 7 mm [Range 100 nm
(1000Å)] was observed (Fig. 39). The Reynolds number in this case corresponds to 2.35 × 10 ⁵ .

That is, a general coating apparatus cannot coat a resist having a Reynolds number of more than 2.35 × 10 ⁵ . A graph of this is shown in FIG. From this graph, it is understood that the rotation speed can be increased only up to 3500 r / min for the 8-inch φ wafer. further,
The wafer diameter will be further increased to 10 inches and 12 inches in the future, but the maximum rotation speed at that time is 240 inches at 10 inches.
At 0 r / min and 12 inches, it is about 1500 r / min, and the film thickness uniformity becomes worse.

As a countermeasure against this, a method of lowering the resist viscosity (10 cp) is considered. By lowering the resist viscosity, the number of rotations is kept low to obtain the desired resist film thickness, but since it is in a state where there are a lot of solvents, it is easily affected by the temperature and humidity of the environment and stable for a long time. The sex becomes worse.

Therefore, there is a strong demand for a method capable of increasing the rotation speed to 4000 r / min even if the wafer diameter becomes large.

The present invention aims to provide a resist coating apparatus capable of suppressing the occurrence of turbulent flow due to high-speed rotation and making the resist film thickness uniform.

[0015]

Therefore, the invention according to claim 1 is provided with a chuck for holding the substrate and a rotating means for rotating the chuck, and the chuck holds the substrate. In a resist coating apparatus that coats the resist dropped on the substrate on the upper surface of the substrate by rotating in a horizontal plane, a disc-shaped device that is close to the substrate held by the chuck and is parallel to the substrate. Of the disk-shaped plate, and its angular velocity (ω ₁ )
Is the angular velocity of the substrate (ω ₂ ), the radius of the substrate (r ₀ ),
The following equation for the dynamic viscosity (ν) of air,

[0016]

The Equation 7] _{│ω 1 -ω 2 │ ≦ (ν} / r 0 2) rotating meet × 2.35 × 10 ⁵ has its solutions.

The invention according to claim 2 is characterized in that a ring-shaped plate is arranged in proximity to and above the substrate held by the chuck and in parallel with the substrate.

According to a third aspect of the present invention, the ring width (L) of the ring-shaped plate is such that the Reynolds number (Re), the radius of the substrate (r ₀ ), the kinematic viscosity of air (ν), The following formula for the angular velocity (ω) of the substrate

[0019]

## EQU8 ## It is characterized by having a relationship of L = r ₀ −√ (Reν / ω).

According to a fourth aspect of the present invention, the angular velocity (ω ₁ ) of the ring-shaped plate member is the angular velocity (ω ₂ ) of the substrate,
For the radius (r ₀ ) of the substrate and the dynamic viscosity of air,

[0021]

[Formula 9] | ω ₁ −ω ₂ | ≦ (ν / r ₀ ² ) × 2.35 × 10 ⁵ It is characterized in that it rotates.

According to a fifth aspect of the present invention, at least a chuck for holding the substrate and a rotating means for rotating the chuck are provided, and the substrate is held by the chuck and rotated in a horizontal plane. In the method of applying the resist dropped on the substrate to the upper surface of the substrate,
Assuming that the radius of the substrate is r and the angular velocity of the substrate is ω,

[0023]

It is characterized in that the coating atmosphere of the substrate is filled with a gas having a kinematic viscosity coefficient larger than ν expressed by ν ≧ r ² ω / 2.35 × 10 ⁻⁵ .

According to a sixth aspect of the present invention, when the radius of the substrate is r and the angular velocity of the substrate is ω, the coating atmosphere of the substrate is expressed by the following formula:

[0025]

[Expression 11] P (mmHg) ≦ 2.50 × 10 ³ × (1 + 0.00367t) / r ² ω It is characterized in that the pressure is smaller than P.

According to a seventh aspect of the invention, the radius of the substrate is r,
When the angular velocity of the substrate is ω, the coating atmosphere of the substrate is expressed by the following formula,

[0027]

## EQU12 ## The characteristic feature is that the temperature is lower than the temperature t represented by t (° C.) ≧ √ (1800 + 30000r ² ω) −314.2.

[0028]

In order to suppress turbulence, the position of the disk-shaped plate body becomes a problem. Therefore, the inventor calculated how the air flows by rotating the wafer and the wind velocity distribution by the following method.

First, the Navier-Stokes equation is a general equation considering changes in viscosity and density, but if the viscosity is constant, it can be simplified as follows.

Navier-S of real viscosity in cylindrical coordinates
Tokes formula

[0031]

[Equation 13]

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

[0033]

[Equation 14]

The meaning of each symbol is shown below.

U _r , uφ, u _x : Velocity t: Time ρ: Density g: Gravitational acceleration h: Height P: Pressure η: Viscosity K: Volume viscous coefficient Here, the disk is centered on an axis perpendicular to its surface. Constant angular velocity ω
Consider the state of rotating at ₀ .

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

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

In the equations (1), (2), and (3), the air flow on the rotating wafer is rotationally symmetrical, so δ / δ.
ψ = 0. Assuming steady uncompressed, δu /
δt = 0,

[0039]

[Equation 15]

It is Therefore, equations (1), (2), and (3) are respectively as follows.

[0041]

[Equation 16]

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

[0043]

[Equation 17]

Under the same conditions as the expressions (4), (5) and (6), the continuous expression is as follows.

[0045]

[Equation 18]

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

When _x = 0, u _x = 0, u _r = 0, u ψ = rω _{0 When} x = ∞ u _r = 0, u ψ = 0 Von Karman is u _r / r, u ψ / r, u _x , P '
(4)-
Equation (7) is simplified to simultaneous differential equations. The method is shown below.

A new variable λ was defined as follows.

Λ = (ω ₀ / ν) ^1/2 x ν: Coefficient of kinematic viscosity Then, the following assumption was made.

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

[0051]

[Formula 19]

Substituting these into equations (4) to (7) simplifies 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) is used. Can be easily integrated to give

[0055]

Equation 20] K = - But [2F + (1/2) H ^2], (8), (9), (11) must be solved simultaneously as simultaneous manner.

Cochran solves this by series expansion. The result is shown in the graph of FIG.

If the value of λ, that is, the number of revolutions ω ₀ , the coefficient of kinematic viscosity ν, and the height x from the wafer are known, G from FIG.
The values of H and F are obtained. By substituting this into the formula assumed by Von Karman, the air velocities u _r , u ψ, u _x can be obtained.

When the wind velocity distribution is calculated using the above method, the results shown in FIGS. 15 and 16 are obtained. FIG. 15 shows the wind speed in the circumferential direction on an 8-inch φ wafer. The air in contact with the wafer moves at the same speed as the wafer, and when it departs from the wafer, it rapidly decelerates, and the wind speed becomes close to “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 becomes maximum around 0.2 mm above the wafer, and becomes close to “0” at a point 1 mm above the wafer.

From FIGS. 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.
It has been found that it is necessary to provide it at a position of 0 ⁵ or more.

By the way, turbulent flow occurs when the gradient of the wind velocity distribution is large. Therefore, in order to reduce the inclination of this distribution, a disk-shaped plate is placed 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 like the wafer. If the rotation direction of the plate is the same as that of the wafer, the inclination of the wind velocity distribution will be small, and the occurrence of turbulence will be suppressed.

(Operation of the Invention of Claim 5) The turbulent flow generation region can be predicted by the Reynolds number (Re), and in the case of the spin coater, according to the experiment, the turbulent flow is Re = 2.35 × 10 ^5. Occur. (The turbulent transition of air is generally 3.2 × 1
It is 0 ⁵ . ) The Reynolds number is generally expressed by the following equation in the case of a rotating body.

[0065]

Re = ρr ² ω / η = r ² ω / ν Re: Reynolds number ρ: Density η: Viscosity coefficient ν: Kinetic viscosity coefficient r: Distance from center of rotation ω: Angular velocity If it is 2.35 × 10 ⁵ or less, no turbulent flow occurs. Therefore, the required kinematic viscosity coefficient of the gas in the coating atmosphere is calculated by the following equation.

[0066]

Ν ≧ r ² ω / Re ≧ r ² ω / 2.35 × 10 ^{5, that} is, the larger the kinematic viscosity coefficient, the less turbulent flow is generated. Therefore, the present inventor calculated how much difference actually exists depending 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 8 inch φ wafer) is rotated. If the atmosphere is air, increasing the rotation speed to 4000 r / min
The number of Reynolds exceeds 2.35 × 10 ⁵ , and turbulent flow occurs. However, in the Ne atmosphere, the Reynolds number is 2.35 × 10 ⁵ or less even if the rotation speed is increased to 8000 r / min, and it is understood that turbulent flow does not occur. In addition, He,
In the H atmosphere, 25,000 r / min is possible.

Further, it was calculated how much size can be applied by spin coating. The results in the He atmosphere are shown in FIG.

From FIG. 20, the diameter of about 500 mm is 4
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. The kinematic viscosity coefficient of the gas studied this time is 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 a region filled with a gas having a high kinematic viscosity, that is, the amount of gas used becomes a problem. Therefore, the wind velocity distribution over the wafer when the above gas was used was calculated. By this calculation, the turbulent flow generation region, that is, the region to be filled with the high kinematic viscosity coefficient can be known. The calculation results will be described below.

The rotation of the wafer causes a flow of gas above it. The wind velocity distribution is von Kar
Calculated using the method of Man and Cochran. The results are shown in FIGS. FIG. 21 shows the wind speed in the circumferential direction at 8 inches φ. The gas in contact with the wafer moves at the same speed as the wafer, and decelerates rapidly when the gas leaves the wafer. The degree of deceleration varies depending on the gas, and the higher the kinematic viscosity, the slower the degree of deceleration. For example, with air, the wind speed drops to 0.2 m / s at a height of 0.7 mm above the wafer, whereas in a He atmosphere, the wind speed becomes 0.2 m / s at a height 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 this acceleration depends on the gas. For example, in the case of air, the maximum wind speed (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, the height is 0.5
Maximum wind speed at mm position and 1 m at 2 mm or more position
/ S. As described above, it is understood that the gas flow is generated in the region where the height above the wafer is 2 mm or less. That is,
It can be seen that the area to be filled with the gas having the high kinematic viscosity in the present invention is about 2 mm on the wafer.

(Operation of the Invention According to Claim 6) <Relationship between Reynolds Number and Atmospheric Pressure> The Reynolds number, which is an index of turbulent flow generation, is defined by the following equation in the case of a rotating disk.

[0074]

Re = ρr ² ω / η = r ² ω / ν (a) Re: Reynolds number ρ: Density η: Viscosity coefficient ν: Kinetic viscosity coefficient r: Distance from rotation center ω: Angular velocity The viscosity coefficient η hardly changes from several tens Pa to several atmospheres. On the other hand, the density changes with atmospheric pressure, and the change is calculated by the following equation.

[0075]

[Equation 24]

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

FIG. 26 is a graph showing this relationship. FIG. 26 shows the number of Rey nozzles 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, Revolution Number and Reynolds Number under Reduced Pressure> FIG. 27 shows the distance from the center of rotation when the pressure is reduced, that is, the relationship between the wafer radius and the Reynolds number. The rotation speed is 4000 r / min.

If the pressure is reduced to 10000 Pa (about 0.1 atm), a wafer having a diameter of 0.5 m can be spin-coated.

Next, FIG. 28 shows the relationship between the number of revolutions and the number of Reynolds when the pressure is similarly reduced. The wafer diameter is 8 inches φ.

From FIG. 28, 50000 Pa (0.5 atm)
If the pressure is reduced to, 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 of 12000 r / min or more becomes possible.

<Method of Obtaining Range of Atmospheric Pressure> The turbulent flow generation region can be predicted by the Reynolds number (Re), and in the case of the spin coating device, according to experiments, turbulent flow is generated at Re = 2.35 × 10 ^5. .. (The turbulent transition of air is generally 3.2 × 10 ^5. ) In the case of a rotating body, the Reynolds number is generally expressed by the following equation.

[0083]

[Equation 25] Re = ρr ² ω / η = r ² ω / ν (c) According to the experiment, if the number of Reynolds is 2.35 × 10 ⁵ or less, turbulent flow does not occur. Therefore, the required kinematic viscosity coefficient of the gas in the coating atmosphere is calculated by the following equation.

[0084]

Ν = η / ρ ≧ r ² ω / Re ≧ r ² ω / 2.35 × 10 ⁵ (d) Here, the viscosity coefficient η hardly changes from several 10 Pa to several atmospheric pressure, and η = 1 It is 830 × 10 ⁻⁵ Pa · s. On the other hand, the density ρ is given by the following equation.

[0085]

[Equation 27]

By substituting equation (e) into equation (d), the range of atmospheric pressure can be obtained.

[0087]

[Equation 28]

<Determination of Area to be Decompressed (Size of Decompression Chamber)> The decompression chamber should be as small as possible. This is because the target atmospheric pressure can be reached in a short time and the capacity of the pump can be small. It is advantageous both economically and in terms of throughput.

Therefore, the wind velocity distribution above the wafer in a reduced pressure atmosphere was calculated. This calculation gives the area to be decompressed. The calculation results will be described below.

The rotation of the wafer causes a flow of gas above it. The wind velocity distribution is von Kar
Calculated using the method of Man and Cochran. The results are shown in FIGS. 29 and 30. FIG. 29 shows the wind speed in the circumferential direction at 8 inches φ. The gas in contact with the wafer moves at the same speed as the wafer, and decelerates rapidly when the gas leaves the wafer. The degree of this deceleration varies depending on the gas, and the lower the atmospheric pressure, the slower the degree of deceleration. And the area where the air moves will also expand.

For example, at 101325 Pa (1 atm),
The wind speed decreases to 2.0 m / s at a height of 0.7 mm above the wafer, 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 this acceleration depends 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
When the pressure is reduced to a (about 0.1 atm), the height is 0.6 mm.
The maximum wind speed is at the position of 1 m / s at the position of 2 mm or more
Fall to.

As described above, the present inventor
It was clarified that the gas flow under reduced pressure (about 0.1 atm) is generated in a region where the height above the wafer is 2 mm or less.
In addition, the pressure that is actually considered necessary is 10,000 Pa.
It is (0.1 atm), and it can be seen that the area to be depressurized in the present invention may be about 2 mm on the wafer.

(Operation of the Invention According to Claim 7) <Relationship between Reynolds Number and Temperature> The Reynolds number, which is an index of turbulent flow generation, is defined by the following equation in the case of a rotating disk.

[0095]

Re = ρr ² ω / η = r ² ω / ν (f) Re: Reynolds number ρ: Density η: Viscosity coefficient ν: Kinetic viscosity coefficient r: Distance from rotation center ω: Angular velocity where air The viscosity coefficient η of changes with temperature, and the change is given by the following equation.

[0096]

Η = η ₀ −4.83 × 10 ⁻⁸ (23−t) (Pa, s) (g) η ₀ : Viscosity coefficient at 23 ° C. Also, the density ρ changes depending on temperature. The change is calculated by the following formula.

[0097]

[Equation 31]

From the expressions (f), (g) and (h), the relationship between the Reynolds number and the temperature can be obtained.

FIG. 33 is a graph showing this relationship. FIG. 33 shows the number of Rey nozzles 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, Number of Rotations and Reynolds Number at Temperature> FIG. 34 shows the distance from the center of rotation when the temperature is raised, that is, the relationship between the wafer radius and the number of Reynolds. The rotation speed is 4000 r / min. If the temperature is raised to 60 ° C., an 8-inch φ wafer can be spin-coated at 4000 r / min.

Next, FIG. 35 shows the relationship between the number of revolutions and the number of Reynolds when the temperature is similarly raised. The wafer diameter is 8 inches φ.

If the temperature is raised from FIG. 35 to 100 ° C., then 5
It can be applied 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 is possible.

<Method of Obtaining Temperature Range> The turbulent flow generation region can be predicted by the Reynolds number (Re), and in the case of the spin coating device, according to experiments, turbulent flow is generated at Re = 2.35 × 10 ^5. .. (The turbulent transition of air is generally 3.2 × 10 ^5. ) In the case of a rotating body, the Reynolds number is generally expressed by the following equation.

[0104]

[Equation 32] Re = ρr ² ω / η = r ² ω / ν (i) According to the experiment, if the Reynolds number is 2.35 × 10 ⁵ or less, turbulent flow does not occur. Therefore, the required kinematic viscosity coefficient of the gas in the coating atmosphere is calculated by the following equation.

[0105]

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

[0106]

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

[0107]

[Equation 35]

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

[0109]

[Equation 36]

Here, since η ₀ = 1.83 × 10 ^-5 , the following quadratic equation is obtained by substituting it into the equation (m).

[0111]

[Equation 37]

By solving the equation (n), the temperature range can be obtained.

[0113]

T ≧ √ (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 should be 48.9 ° C. or higher according to the formula (o). You can see that

<High temperature region (chamber size)
> The chamber should be as small as possible. This is because the target temperature can be reached in a short time, which is economically and throughput advantageous. Therefore, the wind velocity distribution over the wafer when the temperature was raised was calculated. From this calculation, the area where the temperature should be increased can be known. The calculation results will be described below.

The rotation of the wafer causes a flow of gas above it. The wind velocity distribution is von Kar
Calculated using the method of Man and Cochran. The results are shown in FIGS. 36 and 37. FIG. 36 shows the wind speed in the circumferential direction at 8 inches φ. The gas in contact with the wafer moves at the same speed as the wafer, and decelerates rapidly when the gas leaves the wafer. The degree of this deceleration varies depending on the temperature, and the higher the temperature, the slower the degree of deceleration. And the area where the air moves will also expand.

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

FIG. 37 shows the wind speed in the radial direction. In this case, the gas is accelerated by centrifugal force, and this acceleration depends on the temperature. For example, at 20 ° C,
Maximum wind speed (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 at the position of 5 mm, and it is reduced to 1 m / s at the position of 1.4 mm or more.

As described above, the present inventor has clarified that the gas flow under the atmosphere of 300 ° C. occurs in the region where the height above the wafer is 1.4 mm or less. Further, the temperature considered to be actually necessary is about 300 ° C., and it can be seen that the region to be heated in the present invention may be about 2 mm on the wafer.

[0119]

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

(Embodiment 1) A schematic side view of this embodiment is shown in FIG. 1 and a perspective view thereof is shown in FIG.

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

As a result, in an 8-inch φ wafer, 4
Turbulence does not occur even at 000 r / min or more, unevenness in film thickness is suppressed, and film thickness uniformity fluctuates = 4.0 nm (40 Å)
was gotten.

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

[0124]

| Ω ₁ −ω ₂ | = (ν / r ₀ ² ) × 2.15 × 10 ⁵ For example, in an 8-inch φ wafer, 6000 r / mi
In the case of spin coating with n, the rotation speed of the disk 13 is 2610.
It was set to r / min. At this time, the film thickness unevenness of the resist does not occur, and the film thickness uniformity fluctuation range (Range) = 4.0.
nm was obtained.

The rotation speed of the disk was calculated by setting the kinematic viscosity coefficient v of air to 1.57 × 10 ^-5 m ² / s.

(Third Embodiment) In the resist coating apparatus according to the present embodiment, in the structure of the first embodiment, the disk 13 can be moved so as to be positioned above the wafer 11 only when the wafer 11 is rotated. It was done. The application of the resist is performed in an environment where the temperature and humidity are controlled. Therefore, air retention should be as low as possible. On the other hand, if the disk 13 is always arranged above the wafer 11, air may accumulate, so in this embodiment, the disk 13 is movable and can be arranged only when the wafer is rotated.

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

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

First, as shown in FIG. 4A, the wafer 1
1 is held on the wafer chuck 10, and the resist 14 is discharged from the resist discharge nozzle 15. At this time, the disk 1
Reference numeral 3 is a standby position that is far from the wafer 11 to the extent that it does not affect the resist coating atmosphere.

Next, when the resist discharge is completed, as shown in FIG.
As shown in (B), the disk 13 is moved above the wafer 11 by the driving means 17, and at the same time as 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 this embodiment, the size of an 8-inch φ wafer is 4
No turbulence was observed under the condition of 000r / min,
The in-plane uniformity had a fluctuation range of 3.5 nm. In addition, the present example is particularly effective for the stability of the film thickness, and the 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 accumulate. Further, the turbulent flow is generated in a region where the Reynolds number is 2.35 × 10 ⁵ or more. Therefore, the disk 13A was formed into a donut shape.

An explanatory view of this embodiment is shown in FIG. 5, and a perspective view is shown in FIG.
Are shown respectively. In the figure, 18 is the disk 13A for the motor 12
Shows a support connected to.

The disk 13A has a hollow near the center so that air is less likely to stay in it. The position and width of the ring-shaped (doughnut-shaped) disk 13A are obtained by the following equations.

The distance r from the wafer center of the disk 13A

[0136]

R = √ (Reν / ω) Ring width w

[0137]

W = r ₀ −√ (Reν / ω) Reynolds number Re Re = 2.35 × 10 ⁵ Dynamic viscosity coefficient νν = 1.57 × 10 ⁻⁵ m ² / s For example, an 8-inch φ wafer is 6000r. When rotating and applying at a speed of / min, the donut-shaped disc has a width of 25 mm that covers from 75 mm at the center to 100 mm. Even at 6000 r / min, uneven film thickness did not occur.

At this time, the film thickness uniformity is the fluctuation range of the film thickness =
It was 3.5 nm. The present example is particularly effective for the stability of the film thickness, and the uniformity of the total film thickness variation width = 4.0 nm was obtained.

(Embodiment 5) For the above-mentioned reason, the disk 13A is used.
The width of should be as narrow as possible. Therefore, the width of the donut-shaped disc is controlled so as to have the minimum width.

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

[0141]

(42) W = r ₀ −√ (Reν / ω ₁ ) (Embodiment 6) From the above calculation results, the present inventor found that the ring-shaped disk 13A must be within 1 mm above the wafer. It was

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

Distance r from the center of the ring

[0144]

R = √ (Reν / ω) Ring width w

[0145]

W = r ₀ −√ (Reν / ω) Reynolds number Re Re = 2.35 × 10 ⁵ Dynamic viscosity coefficient νν = 1.57 × 10 ⁻⁵ m ² / s It shows in FIG. As shown in FIG. 7, a ring-shaped disc 13A was provided above the wafer 11. FIG. 8 is a perspective view. This embodiment is a machine compatible with 8-inch wafers. Specific dimensions are 83 mm to 100 m from the center of the wafer 11 when coating at a rotation speed of 5000 r / min.
A ring-shaped disc 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 if the rotation speed of the 8-inch φ wafer 11 was increased to 5000 r / min, the film thickness unevenness of the resist did not occur, and the film thickness uniformity of 4 nm (40 Å) was obtained.

(Embodiment 7) In the present embodiment, in the case of a 12-inch φ wafer compatible machine, the setting was specifically made as follows.

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

Even when the rotation speed was increased to 5000 r / min, the film thickness unevenness due to the turbulent flow did not occur. Disk 13A
In the absence of this, the number of revolutions could be increased only up to 1600 r / min, so that the film thickness uniformity had a fluctuation range of 8 n.
Although it was m (80Å), in the present embodiment, the fluctuation range = 4n
A uniformity of m (40 Å) was obtained.

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

65 mm to 100 m from the center of the wafer 11
A ring-shaped disc 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 rotation speed was increased to 8000 r / min, no film thickness unevenness due to turbulent flow was observed, and the film thickness uniformity had a fluctuation range of 3.5 nm (35 Å).

(Embodiment 9) The resist is applied in an atmosphere in which the temperature and humidity are controlled. Therefore, it is better that there are few areas where air stays on the wafer. On the other hand, the ring-shaped disc 13A of this embodiment may cause air retention. Therefore, the wafer having the movable disk 13A is arranged above the wafer only during rotation. Specifically, the structure is as shown in FIG.

As shown in the figure, a ring-shaped disc 13A
Are 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 at a position separated from the upper side of the wafer 11 to the extent that air is not retained. Next, the disk 13A is moved above the wafer 11 by the driving means 17 (FIG. 10 (B)). afterwards,
Before the wafer 11 is rotated or when the rotation is started, the turbulent flow of air due to the rotation of the wafer 11 is suppressed by approaching the upper side of the wafer 11 to a height of 0.5 mm.

Since air retention is reduced by this embodiment, the stability between wafers and lots is particularly improved.
The film thickness uniformity of in-plane film thickness fluctuation range = 4.0 nm (40 Å) was obtained.

(Embodiment 10) For the reasons described above, the width of the ring-shaped disk 13A should be as narrow as possible. On the other hand, the distance from the wafer center of the ring-shaped disk 13A is determined by the rotation speed.

[0159]

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 rotation speed. is there. An explanatory diagram of this embodiment is shown in FIG. The disc 13A has a variable width like a diaphragm 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 drive means 21 controls the width of the disc 13A based on this value.

According to this example, in-plane variation of the in-plane variation width = 4.0 nm (40 Å) was obtained.

(Embodiment 11) In this embodiment, as shown in FIG. 12, the disc 1A is arranged so that the disc 13A does not cause turbulence.
The cross-sectional shape of 3A was streamlined.

According to this example, the occurrence of turbulence was further suppressed, and the film thickness uniformity had a fluctuation range of 3.5 nm.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these, and various design changes associated with the gist of the configuration can be made.

(Embodiment 12) FIG. 14 shows the structure of a coating apparatus used in this embodiment. FIG. 18 shows a coating apparatus that performs spin coating in a Ne atmosphere, and the wafer size to be processed is 8 inches. The cup 20 is sealed with a lid 21 so that it can be filled with Ne. 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 temperature is entirely controlled by an atmosphere temperature controller 24. In the figure, 25 is a discharge nozzle, 26 is a wafer chuck, 2
7 is a wafer, 28 is a hepa filter, 29 is a heat exchanger, 3
0 indicates a Ne gas cylinder.

Next, the operation will be described.

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

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

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, because of the Ne atmosphere, the number of Reynolds can be suppressed to 2.35 × 10 ⁵ or less.

7) After the rotation is stopped, the lid 21 is removed 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), 8000r /
No film thickness unevenness due to turbulent flow 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 the He gas, and resist coating was performed. 2 for He
The film thickness unevenness did not occur up to 5000 r / min, and the film thickness uniformity was Range = 3.5 nm.

(Embodiment 14) This embodiment is an example in which the same effect can be obtained even if a mixed gas of Ne and He is used. When a resist was applied with a mixing ratio of Ne: He = 1: 2, no film thickness unevenness due to turbulent flow was observed up to 15000 r / min, and a film thickness uniformity of Range = 3.8 nm was obtained.

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

(Example 15) Ne gas, He gas, etc. are expensive, for example, Ne gas costs about 10,000 yen / 10l. Therefore, it is necessary to reduce the amount used.

On the other hand, it can be expected that the area filled with this gas may be up to about 2 mm on the wafer as described in the above operation. Therefore, the lid 21 in FIG.
I approached to m. The block diagram is shown in FIG.

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 it can be filled with Ne.
It is sealed with. 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 temperature is entirely controlled by an atmosphere temperature controller 24.

Next, the operation will be described.

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

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

3) The lid 21 comes close to the wafer up to 2 mm,
The resist coating atmosphere is sealed by closely contacting 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, because of the Ne atmosphere, the number of Reynolds can be suppressed to 2.35 × 10 ⁵ or less.

7) After the rotation is stopped, the lid 21 is removed 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), 8000r /
No film thickness unevenness due to turbulent flow was observed up to min. The film thickness uniformity at this time was Range = 4.0 nm.

Further, the amount of Ne gas used was conventionally 2 l per wafer, but was improved to 0.7 l in this embodiment.

(Example 16) FIG. 24 shows a coating apparatus used in this example. FIG. 24 shows a coating apparatus for performing spin coating under reduced pressure, and the wafer size to be processed is 8 inches.
The cup 20 can be closed with a lid 21.
The lid 21 is adapted to escape during wafer transfer and resist discharge. A rotary pump 31 with an output of 500 W is connected to the cup 20, and 10,000 Pa in about 3 seconds.
(About 0.1 atm) is reached.

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

Next, the operation will be described.

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

2) The wafer 27 is carried 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) Cup 2 by rotary pump 3
In 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 reduced, the Reynolds number can be suppressed to 2.35 × 10 ⁵ or less.

7) After the rotation is stopped, the lid 21 is removed 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 Co., Ltd.), 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.
A ge of 4.0 nm was obtained.

Example 17 In FIG. 24, cup 2
The pressure inside 0 was set to 5000 Pa (0.5 atm).
As a result, the time required for depressurization could be shortened from 3 seconds to 1 second. At this time, resist TSMR on the 8-inch φ wafer
When -8900 was applied, the rotation speed was 6500 r / mi
No film thickness unevenness due to turbulence occurs up to n. Range = 4.
A film thickness uniformity of 5 nm was obtained.

(Embodiment 18) When the chamber for depressurization and the cup 20 are smaller in size, the time required for depressurization can be shortened, which is advantageous in terms of throughput and economy. Therefore, based on the calculation result of the above-mentioned action, open the cup lid by 2 m.
It approached to m. The block diagram is shown in FIG.

The operation is the same as in the sixteenth embodiment, only the lid 21 approaches the wafer 27 up to 2 mm. As a result, the time required to reach reduced pressure (10000 Pa) could be shortened to 0.5 seconds. At this time, film thickness unevenness due to turbulence is 12000.
It was not observed up to r / min, and the film thickness uniformity was Range = 4.0 nm under the same conditions as above.

Example 19 In FIG. 25, the pressure of the coating atmosphere was set to 50000 Pa (0.5 atm). The time required for decompression was shortened to 0.1 seconds in combination with the effect that the lid 21 came close to 2 mm.

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

(Embodiment 20) FIG. 31 shows the structure of the 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 with a lid 21. The lid 21 is adapted 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 temperature is entirely controlled by an atmosphere temperature controller 24. The air mixed in the resist is previously removed by using ultrasonic waves.

Next, the operation will be described.

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

2) The wafer 27 is carried 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 fed.

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

7) After the rotation is stopped, the lid 21 is removed 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 Co., Ltd.), 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.
A ge of 4.0 nm was obtained.

(Embodiment 21) In FIG. 31, the cup 2
The temperature within 0 was set to 60 ° C. As a result, the time required to reach the target temperature was shortened from 3 seconds to 1 second. At this time, when a resist TSMR-8900 was applied to an 8-inch φ wafer, film thickness unevenness due to turbulent flow did not occur up to a rotation speed of 4000 r / min, and a film thickness uniformity of Range = 4.5 nm was obtained.

(Embodiment 22) The smaller the size of the chamber and the cup 20 for raising the temperature, the shorter the time required to reach the target temperature, which is advantageous in terms of throughput and economy. Therefore, the lid of the cup was brought close to 2 mm based on the calculation result of the above-mentioned action. The block diagram is shown in FIG.

The operation is the same as in (Embodiment 20), except that the lid 21 approaches the wafer 27 up to 2 mm. As a result, the time to reach 300 ° C. could be shortened to 0.5 seconds. At this time, the film thickness unevenness due to turbulent flow was not observed up to 10000 r / min, and the film thickness uniformity was Range =
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 shortened to 0.1 seconds.

At this time, the film thickness unevenness due to the turbulent flow is 4000
It does not occur up to r / min, and the film thickness uniformity is Range =
4.5 nm was obtained.

Although each embodiment has been described above, each invention is not limited to this, and various design changes and condition changes accompanying the gist of the configuration can be made.

[0224]

As is apparent from the above description, according to the present invention, it is possible to suppress the generation of turbulent flow due to high speed rotation in the resist spin coating method, and therefore the uniformity of the resist film thickness caused by the turbulent flow can be suppressed. The effect of suppressing the deterioration of In particular, it is effective to achieve a film thickness uniformity of ± 25 Å or less.

According to the present invention, the Reynolds number 2.3
Resist coating can be performed at 5 × 10 ⁵ or more, which has the effect of enabling high-speed rotation. For example, it is possible to achieve a high speed of 4000 r / min or more for an 8-inch φ wafer and 1600 r / min or more for a 12-inch φ 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 by one type of resist can be expanded.

Further, according to the inventions of claims 5 to 7, there is an effect that the Reynolds number is suppressed to 2.35 × 10 ⁵ or less.

[Brief description of drawings]

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

FIG. 2 is a perspective view of the first embodiment of the present invention.

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

FIG. 4 is a process explanatory diagram of Embodiment 3 of the present invention.

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

FIG. 6 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 7 is a sectional view of Embodiment 6 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 Embodiment 9 of the present invention.

FIG. 10 is a process explanatory diagram of Example 9 of the present invention.

FIG. 11 is an explanatory diagram of Example 10 of the present invention.

FIG. 12 is a sectional view of Embodiment 11 of the present invention.

FIG. 13 is a graph showing the relationship between the number of Reynolds and the 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 velocity of air.

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

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

FIG. 18 is an explanatory diagram of Example 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 disc center.

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

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

FIG. 23 is an explanatory diagram of a coating device used in Example 15 of the present invention.

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

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

FIG. 26 is a graph showing the 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 rotation center) and the Reynolds number when the pressure is changed.

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

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

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

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

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

FIG. 33 is a graph showing the 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 center of rotation and Reynolds number at a rotation speed of 4000 rpm.

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

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

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

38 (A), (B) and (C) are explanatory views of a coating process by a conventional resist coating apparatus.

FIG. 39 is an explanatory view showing the relationship between resist film thickness and position due to turbulent flow in a conventional example.

[Explanation of symbols]

 10 ... Chuck 11 ... Wafer 12 ... Motor 13 ... Disc

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 14, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 7

[Correction method] Change

[Correction content]

[6] t (° C.) ≧ √ resist method spin coating, characterized in that it has higher than the temperature t, expressed by ^{(1800 + 30000r 2 ω) -314.2} .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

[0027]

[Expression 12] t (° C.) ≧ √ (1800 + 30000r ² ω) −314.2 is higher than the temperature t represented by

Claims (7)

[Claims] 1. A chuck for holding a substrate, and a rotating means for rotating the chuck are provided, and the substrate is dropped on the substrate by being held by the chuck and rotated in a horizontal plane. In a resist coating apparatus that coats a resist on the upper surface of the substrate, a disc-shaped plate body that is close to and above the substrate held by the chuck and that is parallel to the substrate is arranged, and the disc-shaped plate body is disposed. The angular velocity (ω ₁ ) is the angular velocity (ω ₂ ) of the substrate, the radius (r ₀ ) of the substrate, and the dynamic viscosity coefficient (ν) of air.
On the other hand, a resist coating apparatus which is rotated by satisfying the following equation: | ω ₁ −ω ₂ | ≦ (ν / r ₀ ² ) × 2.35 × 10 ⁵ . 2. A chuck for holding a substrate and at least a rotating unit for rotating the chuck, wherein the substrate is held by the chuck and rotated in a horizontal plane to drop the substrate on the substrate. A resist coating apparatus for coating the above resist on the upper surface of the substrate, wherein a ring-shaped plate is arranged in parallel with and above the substrate held by the chuck. apparatus. 3. The width (L) of the ring of the ring-shaped plate body
Is the Reynolds number (Re), the radius of the substrate (r ₀ ),
3. The resist coating apparatus according to claim 2, wherein the kinematic viscosity (ν) of air and the angular velocity (ω) of the substrate have the following equation: L = r ₀ −√ (Reν / ω) . 4. The following equation is given for the angular velocity (ω ₁ ) of the ring-shaped plate body with respect to the angular velocity (ω ₂ ) of the substrate, the radius (r ₀ ) of the substrate, and the dynamic viscosity coefficient of air: The resist coating apparatus according to claim 2, wherein the resist coating apparatus rotates by satisfying | ω ₁ −ω ₂ | ≦ (ν / r ₀ ² ) × 2.35 × 10 ⁵ . 5. A chuck for holding a substrate and at least a rotating means for rotating the chuck are provided, and the substrate is dropped on the substrate by being held by the chuck and rotated in a horizontal plane. In the resist spin coating method of coating the above resist on the upper surface of the substrate, where the radius of the substrate is r and the angular velocity of the substrate is ω, the following equation is obtained: ν ≧ r ² ω / 2.35 A spin coating method for a resist, characterized in that a coating atmosphere of the substrate is filled with a gas having a kinematic viscosity coefficient represented by × 10 ⁻⁵ which is larger than a kinematic viscosity coefficient ν. 6. A chuck for holding a substrate and at least a rotating means for rotating the chuck, wherein the chuck is held by the chuck and rotated in a horizontal plane to drop the substrate on the substrate. In the method of spin-coating a resist for coating the above resist on the upper surface of the substrate, when the radius of the substrate is r and the angular velocity of the substrate is ω, the coating atmosphere of the substrate is expressed by the following formula: ) ≦ 2.50 × 10 ³ × (1 + 0.00367 t) / r ² ω A pressure smaller than the pressure P represented by the resist spin coating method. 7. A chuck for holding a substrate and at least a rotating means for rotating the chuck, wherein the chuck is held by the chuck and rotated in a horizontal plane to drop the substrate on the substrate. In the resist spin coating method of coating the above resist on the upper surface of the substrate, when the radius of the substrate is r and the angular velocity of the substrate is ω, the coating atmosphere of the substrate is expressed by the following formula: t (° C) ) ≧ √ (1800 + 30000r ² ω) −314.2, which is lower than the temperature t represented by the spin coating method of a resist.