JP3563610B2 - Rotary coating device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a spin coating apparatus used for applying a resist or the like to a surface of a semiconductor wafer, for example.
[0002]
[Prior art]
As is well known, a spin coating method is widely used as a method for forming a coating film having a uniform thickness on a coating object such as a semiconductor wafer. This is a method in which an object to be coated on which an application liquid is dropped is rotated, the application liquid is spread over the entire surface of the object by centrifugal force, and a solvent in the application liquid is evaporated to form a coating film.
[0003]
FIG. 14 shows a schematic configuration of a conventional spin coating apparatus that performs the spin coating method described above.
In FIG. 1, reference numeral 1 denotes an object to be coated such as a wafer. The object 1 is horizontally held on a chuck 2 of vacuum suction type. The chuck 2 is connected to a rotating shaft of a motor 4 via a shaft 3. Above the chuck 2, a nozzle 6 for dropping a coating liquid 5 such as a resist on the upper surface of the object 1 is disposed. These components are covered with a cover 7 for preventing the application liquid 5 from scattering and collecting.
[0004]
In order to form a coating film such as a resist on the object to be coated 1 by the apparatus configured as described above, first, the object to be coated 1 is fixed on the chuck 2 and the motor 4 is started to rotate. Then, as shown in FIG. 15, for example, the coating liquid 5 is dropped from the nozzle 6 onto the center of the upper surface of the coating target 1 while the coating target 1 is rotating at a low speed. The nozzle 6 is located at a position retracted from the object 1 before coating. Subsequently, the number of rotations of the object 1 is increased to a predetermined value, and this state is maintained for a certain time.
[0005]
When the object 1 is rotated as described above, the coating liquid 5 spreads over the entire surface of the object by centrifugal force, and the solvent in the coating liquid 5 evaporates, thereby reducing the film thickness (the thickness of the liquid layer). . Although the spread of the coating liquid 5 due to the centrifugal force is dominant in the early stage of the coating process, the decrease in the film thickness causes the evaporation of the solvent to decrease as the viscosity of the coating liquid increases and the fluidity of the coating liquid 5 decreases. It becomes dominant and ends when the solvent cannot finally evaporate from the gas-liquid interface. Therefore, the thickness of the coating film becomes thinner as the number of rotations of the coating object 1 is higher and as the viscosity of the coating liquid 5 is lower.
[0006]
In this way, a coating film is formed on the object 1 to be coated. The coating liquid 5 scattered from above the object to be coated 1 during coating film formation is trapped by the cover 7. However, the conventional spin coating apparatus configured as described above has the following problems.
[0007]
That is, recently, a further reduction in the thickness of the coating film and an increase in the size of the object to be coated 1 have been demanded. In order to realize this further thinning, it is necessary to increase the number of revolutions of the object 1. However, in a conventional spin coating apparatus, when the number of revolutions of the object 1 is increased, the upper surface of the object 1 is increased. Turbulence of the air flow is likely to occur in the outer peripheral area, and there is a problem that the coating thickness unevenness occurs in the outer peripheral area of the upper surface of the coated object 1 due to this effect.
[0008]
For example, as shown in FIG. 16, an object 1 having a certain diameter is taken as an example. The atmosphere gas surrounding the object 1 usually has viscosity. Therefore, when the object 1 rotates, the atmospheric gas that is in contact with the upper surface of the object 1 is discharged in the peripheral tangential direction of the object 1 by a centrifugal pump action with the rotation. Airflow flowing along the upper surface of the member to be coated 1 by a centrifugal pumping action described above, when the speed omega ₁ below there is a rotational angular velocity of the member to be coated 1 flows in a state close to a laminar flow. However, when the rotational angular velocity of the medium to be coated 1 is raised to omega ₂ beyond the omega _1, as shown in FIG. 17, the air flow 8 flows along the upper surface of the member to be coated 1 is greater outer circumferential region, especially the peripheral speed 9 Turbulence. For this reason, the unevenness causes the coating film thickness unevenness region 10 to occur in the outer peripheral region. When the rotation angular velocity of the medium to be coated 1 is raised to the omega ₃ beyond omega _2, turbulence region of the air 8 that flows along the upper surface of the member to be coated 1 is developed to the center side of the member to be coated 1, film thickness unevenness The area 10 also expands toward the center of the object 1. For this reason, the maximum usable rotation speed is necessarily limited.
[0009]
The above-described turbulence of the airflow is determined by the Reynolds number Re represented by the following equation. When the Reynolds number Re increases, the turbulence of the airflow starts. That is, the transition from laminar flow to turbulent flow starts at Re = 86000, and is completely disturbed at Re = 320000. Here, the Reynolds number Re is represented by Re = r ² ω / ν (r: radius of rotation, ω: angular velocity of rotation, ν: kinematic viscosity of atmospheric gas).
[0010]
As is clear from the equation of the Reynolds number Re, the occurrence of the turbulence of the air flow also depends on the size (rotation radius) of the object 1, and as the diameter of the object 1 increases, the diameter of the object 1 decreases. Even at the same rotation speed, turbulence of the air flow occurs in the outer peripheral region. That is, as the diameter of the object to be coated 1 increases, the maximum usable rotational speed thereof becomes lower. In fact, for example, in the case of a semiconductor wafer, the maximum rotation speed at which turbulence does not occur is reduced to about half as the wafer diameter is changed from 6 inches to 8 inches.
[0011]
As described above, in the conventional spin coating apparatus, there is a problem that a coating film having a predetermined thickness cannot be obtained due to an increase in the size of an object to be coated due to a limitation on the maximum number of rotations that can be used. Although it is conceivable to reduce the viscosity of the coating liquid 5 to reduce the thickness of the coating film, there is a limit in adjusting the viscosity of the coating liquid in order to satisfy the original function of the coating liquid.
[0012]
[Problems to be solved by the invention]
As described above, in the conventional spin coating apparatus, the number of rotations (speed) at which the coating thickness unevenness occurs due to the turbulence of the airflow is limited, so that a large coating object or a coating film that requires further thinning is required. There was a problem that it could not be applied to the coated body.
[0013]
Therefore, the present invention can significantly improve the number of revolutions (speed) at which unevenness of the coating thickness occurs due to the turbulence of the air flow, and therefore, it is necessary to further reduce the thickness of the coating film on the large coated object. It is an object of the present invention to provide a spin coating apparatus which can sufficiently cope with a coating body.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a coating object is applied to the surface of the object by rotating the object to which the application liquid can be adhered, and spreading the application liquid on the object by centrifugal force. In the spin coating device for forming, an air supply means for sending an air flow toward the surface on which the coating film is formed on the surface of the object, and a wake from the object with reference to the position of the air supply means. Exhaust means for exhausting the air flow sent by the air supply means, and an inner diameter formed to be smaller than the diameter of the object to be coated, and an outer shape formed to be greater than or equal to the diameter of the object to be coated; An annular body coaxially arranged on the surface of the coating body on which the coating film is formed, and a flow formed between the body to be coated and the annular body by using the entire amount of the air flow sent by the air supply means. Airflow guiding means for guiding the exhaust means through a passage Purge gas flow forming means for flowing an inert gas so as to be guided to the exhaust means side through the outside of the annular body, and forming a purge gas layer around an air flow guided to the exhaust means side by the air flow guide means. It is characterized by comprising.
[0018]
In addition, it is preferable that the air supply means sends a gas having a flow rate larger than a gas flow rate flowing out to the outer peripheral side of the object to be coated toward the object to be coated by a centrifugal pump action by rotation of the object to be coated.
[0021]
In the present invention, an air supply means for arranging an annular body facing the surface on which the coating film is formed on the surface of the object to be coated and sending airflow toward the surface on which the coating film is formed on the surface of the object to be coated, and An exhaust means for exhausting the air is provided, and an air flow guide means for guiding the entire amount of the air flow sent by the air supply means to the exhaust means side through a flow path formed between the coated object and the annular body is provided. In addition, the amount of airflow flowing between the object and the annular body can be kept constant. As a result, it is easy to find the interval between the object to be coated and the annular body in which turbulence does not occur in the coating film forming range, and it is possible to set the best interval.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a spin coating apparatus according to a first embodiment of the present invention. In this figure, the same functional parts as those in FIG. 14 are indicated by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.
[0023]
The different point of the spin coating device according to this example from the conventional device is that an air supply port 21 is provided at a position above the cover 7, that is, at a position above the object to be coated 1, and the air inlet 21 can be adjusted for temperature and humidity. It is connected to an air supply device 22 including a pump, and furthermore, a plurality of exhaust ports 23 are provided at equal intervals in the circumferential direction on the peripheral edge of the low wall of the cover 7, and these exhaust ports 23 are connected to an exhaust device 24 including a pump for coating. A gas supply / exhaust means for forcibly forming an air flow from above to below along the body 1 is provided. The cover 7 can be selectively divided and separated into an upper side and a lower side at an intermediate position in the vertical direction.
[0024]
Here, when the air supply device 22 and the exhaust device 24 are not operated, the flow rate of the gas discharged along the surface of the object 1 by the centrifugal pump action by the rotation of the object 1 is larger than the gas flow rate. What has the ability to supply and exhaust gas at a flow rate is used.
[0025]
Next, an example of use of the spin coating device configured as described above will be described.
First, the object to be coated 1 is fixed on the chuck 2 in a state where the cover 7 is divided and separated in the vertical direction, and the motor 4 is started to rotate in a state where the cover 7 is connected again. Next, a predetermined amount of the coating liquid 5 is dropped from the nozzle 6 onto the center of the upper surface of the object 1 while the object 1 is rotating at a low speed. Subsequently, the operation of the air supply device 22 and the exhaust device 24 is started, the number of revolutions of the object 1 is increased to a predetermined value, and this state is maintained for a certain time. The application liquid 5 can be dropped after the number of rotations of the object 1 is increased to a predetermined value. Except for the step of operating the air supply device 22 and the exhaust device 24, the operation is the same as when the conventional device is used.
[0026]
When the exhaust device 24 is operated as described above, an airflow is formed from the air supply port 21 to the exhaust port 23, and the rotation of the object 1 is formed on the upper surface of the object 1 as shown in FIG. As a result, a forced airflow 25 is formed from the upper side to the lower side of the object to be coated 1 by an amount larger than the discharge flow rate.
[0027]
The forced airflow 25 functions to suppress airflow turbulence on the upper surface of the object 1 as the object 1 rotates, that is, when airflow soars. I do. Therefore, the rotation speed at which the turbulent flow occurs can be increased as compared with the case where the exhaust device 24 is operated and the forced airflow 25 is not formed. Therefore, it is possible to make the coating film thinner than the conventional apparatus, and at the same time, it is possible to suppress the occurrence of coating film thickness unevenness.
[0028]
Note that the discharge flow rate Q accompanying the rotation of the object 1 is generally given by the following equation.
Q = 0.885πr ² (νω) ^0.5 (1)
In the equation (1), r is the radius of rotation, ν is the kinematic viscosity of the atmospheric gas, and ω is the rotational angular velocity.
[0029]
The flow rate of the forced airflow 25 supplied onto the coating target 1 can be controlled by the exhaust flow rate from the exhaust port 23. That is, the atmospheric gas may be supplied such that the exhaust gas flow rate is equal to the ratio of the opening area of the cover 7 on the same plane as the object 1 to the object 1 to the target supply flow rate. Now, _{r 1} the radius of the medium to be coated 1, and the radius of the opening of the cover 7, _{r 2,} if the exhaust flow rate ^{_{(r 2 2 / r 1 2}} ) Q, rotated with respect to the medium to be coated 1 Is given by the discharge flow rate Q associated with.
[0030]
As shown in the experimental results of FIG. 3, there is a relationship between the flow rate of the forced air flow, that is, the supply flow rate and the turbulence generation rotation speed, that the turbulence generation rotation speed increases as the supply flow rate increases. In FIG. 3, ω is the number of revolutions at which turbulence occurs in the stationary fluid, and Q is the discharge flow rate at that time. Therefore, the number of rotations is determined according to the diameter of the object 1 to be coated, the viscosity of the coating solution 5, the required thickness of the coating film, and the like, and the supply flow rate at which the turbulence does not occur may be selected at this number of rotations. .
[0031]
As described above, in the spin coating apparatus according to this example, the airflow 25 as shown in FIG. Turbulence of the airflow generated on the outer periphery of the object 1 due to the rotation can be suppressed, and it is possible to suppress the occurrence of unevenness in the coating thickness on the outer periphery of the object 1.
[0032]
FIG. 4 shows a schematic configuration of a spin coating apparatus according to a second embodiment of the present invention. Also in this figure, the same functional portions as those in FIG. 14 are indicated by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.
[0033]
In the spin coating apparatus according to this example, an annular body 31 is provided above the object 1 to face the upper surface of the object 1 so as to include the outermost peripheral region of the object 1.
That is, the annular body 31 is formed such that the inner diameter is smaller than the diameter of the object 1 and the outer diameter is greater than or equal to the diameter of the object 1, and the distance between the annular body 31 and the object 1 is constant in the circumferential direction. It is installed coaxially with the body 1 via a support mechanism (not shown). Therefore, the central part of the annular state 31 is opened so that atmospheric gas can be introduced.
[0034]
In this spin coating apparatus, the step of forming the coating film is the same as in the previous example.
In this way, if the annular body 31 is disposed above the object 1 in the above relationship, the airflow generated on the upper periphery of the object 1 with the rotation of the object 1 will be disturbed. In this case, this disturbance is suppressed by the annular body 31.
[0035]
That is, as shown in FIG. 5, the uniform air flow 32 along the upper surface of the coating target 1 rises as a vortex, so that even if it is turbulent, the annular body 31 disposed above the coating target 1 and the lower portion thereof Turbulence is suppressed. Therefore, it is possible to increase the number of revolutions of the object 1 to reduce the thickness of the coating, and at the same time, it is possible to suppress the occurrence of unevenness in the thickness of the coating on the outer peripheral portion of the object 1.
[0036]
Note that the turbulence suppression effect of the annular body 31 largely depends on the distance L between the annular body 31 and the object 1, that is, the gap between the annular body 31 and the object 1. FIG. 6 shows an experimental result obtained by examining the relationship between the distance L to the object 1 and the rotation speed at which turbulence occurs. In this figure, ω indicates the turbulent rotation speed when the annular body 31 is not provided.
[0037]
As can be seen from FIG. 6, the turbulence suppression effect increases as the distance L between the object 1 and the object 1 decreases. It should be noted that the annular body 31 extends from at least the position (the radius determined by the Reynolds number Re = 86000) to the outermost circumference where the airflow on the coating object 1 starts to transition from laminar flow to turbulent flow with respect to the required rotation speed. Must be covered. Therefore, the outer diameter of the annular body 31 is determined by the outer diameter of the body 1 to be coated, and the inner diameter of the annular body 31 is determined by the rotation speed of the body 1 to be coated as shown in FIG. FIG. 7 shows calculation results obtained in the air at 1 atm and 25 ° C. That is, the inner diameter of the annular body 31 needs to be reduced as the number of rotations of the object 1 increases.
[0038]
If the above condition is satisfied, the shape of the annular body 31 does not need to be a flat plate parallel to the object 1 as shown in FIG. 4, but as shown in FIG. An annular body 31a having a shape in which the distance L to the object 1 gradually increases as approaching the center of the object 1 or the center of the object 1 as shown in FIG. An annular body 31b having a shape in which the distance L from the intermediate position approaching the portion to the object 1 gradually increases may be used.
[0039]
When an annular body 31a (31b) as shown in FIG. 8 is used, it is easy to introduce the atmospheric gas onto the object 1 and the flow rate of the atmospheric gas gradually increases toward the outer periphery of the object 1. Therefore, there is an advantage that discontinuity of the atmospheric gas on the object 1 is hardly generated.
[0040]
In addition, the material which comprises an annular body does not need to be a dense board, and may be a thing with a fine hole. Further, the outermost periphery of the annular body does not need to be circular, but may be polygonal.
[0041]
FIG. 9 shows a schematic configuration of a spin coating apparatus according to a third embodiment of the present invention. In this figure, the same functional parts as those in FIG. 1 are indicated by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.
[0042]
In the spin coating apparatus according to this example, the annular body 31 is disposed so as to face the upper surface of the coating target 1 as in the apparatus shown in FIG. However, in this example, a structure is employed in which the outer peripheral edge of the annular body 31 is extended outward, and the outer peripheral portion of the extended portion 33 is airtightly fixed to the cover 7. By adopting such a structure, the extension portion 33 is provided with an airflow guiding function, and the entire amount of the airflow sent from the air supply device 22 is controlled by the flow formed between the annular body 31 and the object 1. It is made to flow downstream through the road. In this example, the cover 7 is selectively divided in the vertical direction at a position between the portion where the extension portion 33 is fixed on the peripheral wall of the cover 7 and the portion where the exhaust port 23 is provided. A separating mechanism (not shown) is provided, and when the object 1 is fixed to the chuck 2, a fixing operation is performed using the separating mechanism.
[0043]
Here, the air supply device 22 and the exhaust device 24 have a flow rate larger than the flow rate of gas discharged along the surface of the object 1 by the centrifugal pump action by the rotation of the object 1 when they are not operated. What has the ability to supply and exhaust the gas of this type is used.
[0044]
Next, an example of use of the spin coating device configured as described above will be described.
First, the cover 7 is vertically separated by using the above-described separating mechanism. In this state, the object 1 is fixed on the chuck 2 and the cover 7 is reconnected. Next, the motor 4 is started to rotate, and a predetermined amount of the coating liquid 5 is dropped from the nozzle 6 onto the center of the upper surface of the object 1 while the object 1 is rotating at a low speed. Subsequently, the operation of the air supply device 22 and the exhaust device 24 is started, the number of revolutions of the object 1 is increased to a predetermined value, and this state is maintained for a certain time to form a coating film. The application liquid 5 can be dropped after the number of rotations of the object 1 is increased to a predetermined value.
[0045]
When the air supply device 22 and the exhaust device 24 are operated as described above, as shown in FIG. 10, the forced air flow from the air supply port 21 to the exhaust port 23 by an amount larger than the discharge flow rate accompanying the rotation of the object 1 A flow 34 is formed, and the entire amount of the forced airflow 34 flows through a flow path formed between the object 1 and the annular body 31.
[0046]
As described above, flowing the entire amount of the forced airflow 34 to the flow path formed between the object 1 and the annular body 31 has the following meaning. That is, as described above, in order to suppress the turbulence of the airflow flowing along the coating film forming surface of the object 1, it is effective to dispose the annular body 31 so as to face the object 1. .
[0047]
According to this method, if the position of the annular body 31 is closer to the object 1 to be applied, the effect of suppressing the turbulence of the air flow is great. However, on the other hand, the influence of the annular body 31 appears on the radial thickness distribution of the coating film. That is, when the thickness distribution of the coating film is viewed in the radial direction, the thickness of the coating film rapidly changes at the insertion position of the annular body 31 (the inner edge position of the annular body 31). In order to avoid this, the distance L between the annular body 31 and the object to be coated 1 may be increased. However, in this case, turbulence of the airflow is likely to occur. In other words, the installation position of the annular body 31 has two trade-offs, and the installation position must be experimentally determined while actually forming the coating film.
[0048]
In such an apparatus, it is necessary to form a coating film having a different thickness with the same resist under different conditions, for example, using the same resist, or to form a coating film having the same film thickness with a different resist in order to increase the utilization efficiency of the device. Therefore, the method of determining the position of the annular body over a long period of time has many disadvantages such as time constraints and the need to accumulate know-how. Therefore, how to find the optimum position of the annular body 31 in a short time becomes a problem. However, as shown in FIG. In such a case, the airflow supplied from the air supply device 22 is divided into two flows: an airflow A flowing along the surface of the coating object 1 inside the device and an airflow B flowing outside the annular body 31. Will happen. The amount of the air flow affecting the thickness distribution in the radial direction, that is, the amount of the air flow A flowing along the surface of the coating object 1 increases as the distance L between the annular body 31 and the coating object 1 decreases. The fluid resistance decreases and increases when the fluid resistance increases. Therefore, when the distance L between the object 1 and the annular body 31 that affects the film thickness distribution is changed, the amount of the airflow A flowing along the surface of the object 1 that affects the film thickness unevenness also increases. It will change at the same time, making it extremely difficult to adjust.
[0049]
However, as in the example shown in FIG. 9 (FIG. 10), if the structure is such that the entire amount of the forced airflow 34 flows through the flow path formed between the object 1 and the annular body 31, the annular body 31 Even if the distance L to the coating body 1 is changed, the amount of airflow flowing along the surface of the coating body 1 which affects the film thickness unevenness can be kept constant, so that the distance L at which a uniform film thickness is obtained. Can be easily set.
[0050]
That is, in the spin coating device configured as described above, in order to ensure the uniformity of the coating film formed on the coating target 1, the rotation speed, atmosphere, temperature, humidity, and the coating liquid that are actually used are used. It is necessary to confirm the uniformity by actually applying the film and measuring the film thickness. If the predetermined uniformity is not obtained, the distance L between the annular plate 31 and the object 1 may be adjusted to obtain the predetermined uniformity. Can be easily set.
[0051]
FIG. 12 shows a schematic configuration of a spin coating apparatus according to a fourth embodiment of the present invention. In this figure, the same functional parts as in FIG. 9 are indicated by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.
[0052]
In this rotary coating device, a duct 36 having an inner diameter substantially equal to the inner diameter of the annular body 31 is coaxially arranged with the coating object 1 from the outlet of the air supply device 22 toward the upper surface of the coating object 1. An annular body 31 is fixed to the lower end edge of 36. The duct 36 is provided so as to be vertically movable in the figure by a support mechanism (not shown).
[0053]
Therefore, also in this example, the entire amount of the airflow supplied from the air supply device 22 flows toward the exhaust port 23 through the flow path formed between the annular body 31 and the application target 1, As in the previous example, the distance L at which a uniform film thickness can be obtained can be easily set.
[0054]
FIG. 13 shows a schematic configuration of a spin coating apparatus according to a fifth embodiment of the present invention. In this figure, the same functional parts as those in FIG. 12 are denoted by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.
[0055]
In this spin coating apparatus, unlike the example of FIG. 12, the cover 7 has a hermetically sealed structure, and gas inlets 37 are provided on the upper wall of the cover 7 at equal intervals in the circumferential direction. An inert gas is supplied into the cover 7 via the cover 37. Also in this example, the cover 7 can be selectively divided and separated into an upper side and a lower side at an intermediate position in the vertical direction.
[0056]
Usually, such a device is often operated under a general atmosphere (in the air). However, since some special coating liquids have a property that dislikes humidity, in this example, an inert gas is allowed to flow. It has a structure that can block outside air.
[0057]
The shape of the annular body is not limited to a circle, but may be a polygon. The thickness may not be constant as long as the thickness is symmetric with respect to the center of rotation. Further, the spin coating apparatus described here can be used for forming a coating film not only on a semiconductor wafer but also on various objects to be coated.
[0058]
【The invention's effect】
As described above, according to the present invention, the number of revolutions (speed) at which unevenness of the coating film thickness due to turbulence of the air flow can be significantly increased, so that a large object or a thin coating film can be formed. It can sufficiently cope with a required object to be coated.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a spin coating device according to a first embodiment of the present invention; FIG. FIG. 4 is a diagram showing a relationship between an amount and a turbulent flow generation rotational speed. FIG. 4 is a schematic configuration diagram of a spin coating apparatus according to a second embodiment of the present invention. FIG. FIG. 6 is a view showing the relationship between the distance between the object to be coated and the annular body and the number of rotations at which turbulence occurs in the same apparatus. FIG. 8 is a view for explaining a modification of the annular body. FIG. 9 is a schematic configuration view of a spin coating apparatus according to a third embodiment of the present invention. FIG. 10 is a forced air flow in the apparatus. FIG. 11 is a view for explaining a flow form of forced airflow in a reference example. FIG. 12 is a schematic configuration diagram of a spin coating device according to a fourth embodiment of the present invention. FIG. 13 is a schematic configuration diagram of a spin coating device according to a fifth embodiment of the present invention. FIG. 15 is a diagram illustrating an example of an operation mode of the spin coating device. FIG. 16 is a diagram illustrating a problem of the same device. FIG. 17 is a diagram illustrating a problem of the same device. [Description of reference numerals]
DESCRIPTION OF SYMBOLS 1 ... Coating object 2 ... Chuck 3 ... Shaft 4 ... Motor 5 ... Coating liquid 6 ... Nozzle 7, 7a ... Cover 21 ... Air supply port 22 ... Air device 23 ... Exhaust port 24 ... Exhaust device 25, 34 ... Forced air flow 31 .., 31a, 31b... Annular body 32... Air flow 33... Extension part 36 as air flow guide means... Duct 37.

Claims (1)

In a rotary coating apparatus for forming a coating film on the surface of the object to be coated by rotating an object to which the application liquid can be attached and spreading the application liquid on the object by centrifugal force, the object to be coated is provided. wherein the surface of the air supply means for feeding an air flow toward a surface to be formed of a coating film, provided at a position downstream side after the member to be coated on the basis of this air supply means, fed by the air supply means Exhaust means for exhausting the air flow, a surface having an inner diameter formed smaller than the diameter of the object to be coated, and an outer shape formed to be greater than or equal to the diameter of the object to be coated, on which the coating film of the object to be coated is formed; An annular body coaxially and opposed to the air flow guide means for guiding the entire amount of the air flow sent by the air supply means to the exhaust means side through a flow path formed between the coated object and the annular body. If, outside the street the exhaust hand of said annular body As can be derived in the side stream of inert gas, rotation, characterized by comprising; and a purge gas stream forming means for forming a layer of purge gas around the air flow directed to the exhaust unit side by the air flow guiding means Coating device.

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