JPH09187707A - Coating method and coating apparatus employed therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method by which a coating film can be formed uniformly on the surface of a material to be coated and a coating material which is stuck to the back side during spin coating can be removed and to provide a coating apparatus to be employed for the method. SOLUTION: This apparatus is an apparatus to form a coating film on the surface of a material 4 to be coated by supplying a coating material to the surface of the material 4 to be coated. The coating apparatus has a treatment container 10 having an aperture 20a formed in the center and a contact part 30 positioned in the surrounding of the aperture 20a. The apparatus also has an axial part extended upward through the aperture 20a and a holding means 31 installed in the upper end of the axial part and including a holding part for the material 4 to be coated. Moreover, the apparatus has elevating and lowering means 14, 33 to bring the material 4 to be coated into contact with the contact part 30 by relatively elevating or lowering the treatment container 10 and the holding part. Further, the apparatus has a first rotating and driving means 40 to rotate and drive the treatment container 10 of which the contact part 30 contact the material 4 to be coated and to unitedly rotate the treatment container and the material 4 to be coated. Furthermore, the apparatus has a second rotating and driving means 32 to rotate the holding part by which the material 4 to be coated is held. The apparatus further has a cleaning apparatus to clean the back side of the material 4 to be coated which is held by the holding part and rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for storing a material to be coated in a processing container and applying the coating material while rotating the material to be coated, such as a semiconductor manufacturing apparatus, in which a resist is applied onto a wafer. The present invention relates to a coating method for coating and a coating device used for the coating method.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus, when applying a resist on a wafer, the wafer is placed and fixed on a rotatable spin head arranged inside a processing container, and the resist solution is applied while rotating the wafer. It is supplied to the wafer surface for resist coating (Japanese Patent Publication No. 53-37189).
.

On the other hand, in recent years, in order to increase the number of chips that can be formed on one wafer, there has been an increasing demand for using a larger-diameter, for example, an 8-inch wafer instead of the conventional 6-inch wafer. Alternatively, there is a demand for the use of a square wafer that can efficiently secure chips in order to cope with a liquid crystal screen.

[0004]

Generally, in order to apply the resist thinly and uniformly on a large-diameter wafer, it is generally considered to either change the viscosity of the coating material or increase the rotation speed of the coating material. Had been.

In order to respond to the above demands on the coating apparatus side,
The only method was to increase the number of rotations of the material to be coated, but when the number of rotations was increased, the rotation speed (tangential speed) was greatly different between the center and the peripheral edge of the wafer. And
In particular, if the speed at the peripheral edge of the wafer, where the speed difference from the surrounding space is remarkable, exceeds a predetermined value, evaporation of the solvent as a coating material is accelerated, and the uniformity of resist coating at the peripheral edge is rather impaired. Confirmed by the inventors.

As described above, when applying a resist to a large-diameter wafer, the resist application range is naturally limited only by coping with the number of rotations of the wafer, and the resist of a large-diameter wafer such as an 8-inch wafer is surely removed. Could not do.

By the way, Japanese Patent Laid-Open No. 61-194829 proposes a technique for forcibly introducing a vapor stream of a solvent into the processing container in order to stabilize the quality of the coating film. It has been confirmed by the present inventors that the resist on the large-diameter wafer cannot be reliably performed.

Here, Japanese Patent Application Laid-Open Nos. 51-39737 and 60-143871 disclose techniques for rotationally driving a processing container in which a wafer is placed in the same direction as the wafer. According to these techniques, the promotion of evaporation of the solvent on the wafer is suppressed, and the uniformity of resist application at the peripheral portion of the wafer can be improved.

Here, it is known that when the uniformity of the coating film on the peripheral portion of the wafer is enhanced, a part of the coating material wraps around the back surface of the wafer and contaminates the back surface side of the wafer. For this reason, in JP-A-60-143871, a resist thinner is supplied to the back surface of the wafer to clean the back surface of the wafer.

Thus, cleaning the back surface of the wafer is necessary in order to prevent contamination of the carrying member and to carry out the carrying stably when carrying the wafer after the resist spin coating process. In addition, it is important because it does not bring the contamination of the wafer that causes particles into the next process.

However, according to the conventional apparatus, all of the coating material that has come around the back surface of the wafer during spin coating may not be cleaned in the back surface cleaning step.

Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, to reliably coat a coating material having a large diameter in a desired range on the surface of the coating material, and to prevent contamination. An object of the present invention is to provide a coating method capable of surely cleaning the back surface of the applied material and a coating apparatus used for the coating method.

[0013]

A coating method according to the invention of claim 1 is a coating method of rotating a coating material to coat the coating material, wherein the back surface of the coating material is held by a holding portion. The step of holding and arranging the material to be coated in the processing container by the relative movement of the holding portion and the processing container, and the material to be coated at a position outside the holding position in the holding portion. A rotation in which the back surface of the processing container is brought into contact with the processing container, and the processing container and the coating material are integrally rotated in the same direction to form a coating film by the coating material supplied to the surface of the coating material. A coating step, and a back surface cleaning step of holding the back surface of the coating material on which the coating film is formed by the holding portion and rotating the holding portion to wash the back surface of the coating material. Characterize.

According to the invention of claim 1, the following operational effects (a) and (b) are obtained.

(A) After the material to be coated is placed in the processing container, the spin coating step and the back surface cleaning step are performed. Here, in the back surface cleaning step of rotating the material to be coated to clean the back surface of the material to be coated, the back surface of the material to be coated on which the coating film is formed is located at a position inside the supporting position in the rotation coating step. I support you.
For this reason, even if the coating material wraps around the portion where the coating material was supported during spin coating, this portion can be exposed and cleaned in the back surface cleaning step. Therefore, the back surface of the material to be coated, which is contaminated by the coating material wrapping around during spin coating, can be reliably cleaned in the back surface cleaning step.

(B) Since the processing vessel is rotating in the same direction as the material to be coated, the relative speed difference between the rotation of the material to be coated and the processing container is small (the relative speed difference is the same for the same number of rotations). Even if the material to be coated has a large diameter, evaporation at the peripheral edge is suppressed, and the coating material can be reliably applied in the desired region. Further, since the evaporation amount can be reduced, the amount of the coating material to be dropped on the coating material can be reflectively reduced.

In the coating method according to the second aspect of the invention, a processing container having an opening formed at the center and an abutting portion arranged around the opening, and extending upward through the opening. When applying the coating material on the surface of the material to be coated by using a coating device having a shaft portion and a holding means having a holding portion formed at the upper end of the shaft portion, the holding portion is located above the processing container. And a step of holding the back surface of the material to be coated in a holding portion, and the holding portion holding the material to be coated and the processing container are moved up and down relatively, and the back surface of the material to be coated is A step of bringing the processing container into contact with the contact portion; a step of bringing the back surface of the coating material into close contact with the contact portion by the holding force of the holding means; and the processing container integrally with the coating material. It is rotated in the same direction and supplied to the surface of the coated material. A spin coating step of forming a coating film on the coating material by the coating material, and a back surface cleaning step of subsequently cleaning the back surface of the coating material while rotating the coating material having the coating film formed thereon. , Are included.

According to the invention of claim 2, it is possible to obtain the same operational effect as the above (b) of claim 1.

In addition, the holding means is not in contact with the back surface of the material to be coated, but only the contact portion is brought into close contact with the back surface of the material to be coated in the region between the material to be coated and the holding means. Since it is sealed, the material to be coated can be closely supported on the processing container side. Furthermore, the presence of the contact portion can prevent the coating material from scattering and adhering inward in the radial direction from the contact portion region on the back surface of the material to be coated during spin coating.

The coating method according to the invention of claim 3 is the coating method according to claim 2, wherein the back surface cleaning step holds the material to be coated by the holding means, and the holding means. The coating material is rotated by.

According to the invention of claim 3, in the back surface cleaning step, the material to be coated is held only by the holding means. The holding position by this holding means is a position inside the position of the contact portion during spin coating. Therefore, in the back surface cleaning step, the back surface region of the material to be coated, which the contact portion during the spin coating was in contact with, is exposed, and the coating material that has entered this region can be reliably removed.

This makes it possible to prevent the support portion and the like from being contaminated by the coating material adhering to the back surface of the coating material when the coating material is subsequently transported or processed in the next step.

The coating apparatus according to the invention of claim 4 supplies the coating material to the surface of the coating material and rotates the coating material to form a coating film on the surface by the coating material. In the coating apparatus to be formed, a processing container having an opening formed in the center and an abutting portion arranged around the opening, a shaft portion extending upward through the opening, and provided on an upper end of the shaft portion. Holding means having a holding portion for the coated material, elevating means for moving the processing container and the holding portion relative to each other to bring the coated material into contact with the contact portion, A first rotation driving unit that rotationally drives the processing container in which the coating material is in contact with a contact portion to integrally rotate the processing container and the coating material to form the coating film; Rotate the holding part that holds the coated material on which the film is formed. A second rotation drive means that is characterized by having a a scrubber for cleaning the back surface of the object to be coated material is rotated held by the holding unit.

According to the invention of claim 4, when the coating film is formed on the surface of the material to be coated, the material to be coated is rotated by the first rotation drive means, and then the material to be coated is rotated. When cleaning the back surface, the back surface cleaning is performed by rotating the material to be coated by the second rotation driving means. Here, since the first rotation driving means can integrally rotate the material to be coated and the processing container, if the processing container and the material to be coated are rotated in the same direction, the processing container and the material to be coated can be rotated. The relative speed difference between the rotations becomes small, the evaporation at the peripheral edge is suppressed even for a large-diameter coating material, and the coating material can be reliably applied in the desired region. Moreover, since the amount of evaporation can be reduced, the amount of the coating material to be dropped on the coating material can be reflectively reduced.

The coating apparatus according to the invention of claim 5 is the coating device according to claim 4, wherein the contact portion is
The coating material scattered from the coating material during spin coating,
It is characterized in that it is also used as a coating material adhesion preventing means for preventing the material from being adhered to the inner area of the abutting portion in the back surface area of the material to be coated.

According to the invention of claim 5, the coating material adhesion preventing means exposes the back surface region of the coating material to which the contact portion at the time of spin coating was abutted, and the area around this region is exposed. It is possible to reliably remove the dented coating material. This makes it possible to prevent the support part and the like from being contaminated by the coating material attached to the back surface of the coating material when the coating material is subsequently conveyed or processed in the next step.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings.

The drawing is a cross-sectional view of the embodiment apparatus.

In this figure, the apparatus of this embodiment has a lower base 1, an upper base 2 and columns 3 and 3 for fixing the bases 1 and 2 in parallel with each other so as to be spaced apart from each other.

A processing container 10 for mounting and fixing a wafer 4, which is an example of a material to be coated, is composed of first and second containers 11 and 12 that are closed during coating and can be separated from each other except during coating. ing.

The first container 11 arranged on the upper side is supported by the movable plate 13 via the mounting bases 10A and 13A, and can be raised to the position shown by the chain double-dashed line in FIG. The movable plate 13 is provided with a shaft 1 of a lifting drive unit 14 as a second lifting drive unit fixed to the upper base 2.
5 and a guide member 17 having one end of a guide shaft 16 fixed thereto and the other end provided on the upper base 2.
As described above, the above-described up-and-down movement is enabled by slidably supporting the base. The mounting bases 10A and 13A
Are rotatable with each other via a bearing 18. The mounting bases A and 13A and the bearing 182 constitute a driven guide member that rotatably supports the first container 11. Further, a packing 19 is provided on a peripheral portion of the first container 11 so that the processing container 10 can be hermetically sealed.

The second container 12 on the lower side is supported by a rotation drive mechanism section 40 as a first rotation drive means or a container rotation drive means having the following structure. That is,
A support base 20 is fixed to the lower base 1, and a rotation block 22 which is a rotation driven shaft rotatable around the support base 20 via a bearing 21 is provided. The second container 12 is fixed to the rotating block 22 so that it can rotate integrally. Also,
A first pulley 23 is fixed around the rotation block 22.

On the other hand, a second motor 24 is arranged on the lower base 1, and a second pulley 26 is fixed around the output shaft 25 which is a rotary drive shaft. By suspending a belt 27 as a tension member between the first and second pulleys 23 and 26, the rotational force of the second motor 24 is transmitted to the rotary block 22. As described above, the rotational power from the second motor 24 is transmitted to the second container 12 side via the belt 27 that is a stretching member. Transfer of the generated heat to the second container 12 side can be reduced. As a result, it is possible to prevent a change in the coating environment temperature that affects the coating characteristics.

In the central region of the second container 12, there is provided a hollow disk-shaped vacuum adsorption part 30 which projects from the inner surface of the second container 12 and functions as an abutting part.
The wafer 4 placed in the chamber 0 can be vacuum-sucked. Since the vacuum suction unit 30 is fixed to the second container 12 with screws or the like, the vacuum suction unit 30 can be integrally rotated with the second container 12. Further, a spin chuck 31 as a holding means is disposed inside the vacuum suction unit 30. The spin chuck 31 is provided with a hole 2 forming a hollow portion formed at the center of the support base 20.
The lower base 1 is connected to a first motor 32 supported by the lower base 1 so as to be able to move up and down. The hole 20 </ b> A is open inside the vacuum suction part 30 of the second container 12. The spin chuck 31 has a holding portion capable of holding the wafer 4 on the upper end side of the shaft portion extending upward through the opening. In the present embodiment, the holding portion is configured as a vacuum suction portion. An elevating drive unit 33 and a guide shaft 34 are fixed to both sides of the first motor 32 on the lower base 1, and one of the support frames 35 supporting the first motor 32 is connected to a first elevating drive unit. Is fixed to an elevating shaft 33A of the elevating drive unit 33, and the other is slidably supported along the guide shaft 34 via a bearing 36. As a result, the spin chuck 31 is vertically movable and rotatable. Further, a compressor (not shown) is connected to the spin chuck 31 so that the wafer 4 can be vacuum-sucked. Further, in order to enable suction by the vacuum suction unit 30, a negative pressure is connected to the vacuum suction unit 30. The pressure path is also used. In the apparatus of the present embodiment, the dropping portion of the coating material is not shown, but this dropping portion is located above the wafer 4 when the first container 11 is raised to the position shown by the two-dot chain line in FIG. Then, a predetermined amount of a coating material (a resist material in the present embodiment) is dropped on the center of the wafer 4 and then returns to the initial position.

The operation of the embodiment apparatus configured as described above will be described.

First, the elevating and lowering drive unit 14 is driven to raise the first container 11 to the position shown by the chain double-dashed line in the figure, and the processing container 10 is released. The material is dropped in sequence. After that, the first container 11 is lowered by the driving of the elevation drive unit 14, and the processing container 10 is moved by the first and second containers 11 and 12.
Seal.

Next, a compressor (not shown) is driven,
The vacuum suction unit 30 can be suctioned via the spin chuck 31 and the wafer 4 is suctioned by the vacuum suction unit 30 as shown in the drawing (in this state, the spin chuck 31 is in the vacuum suction unit 30 as shown in FIG. Waiting at a position below the suction surface of). Although the spin chuck 31 is not in contact with the back surface of the wafer 4, the region between the wafer 4 and the spin chuck 31 is sealed by the close contact between the wafer 4 and the vacuum suction unit 30. The wafer 4 can be tightly supported on the second container 12 side by setting the area to a negative pressure. Thereafter, the set diameter of the wafer 4 is set,
The second motor 24 is driven at a rotation speed determined by characteristics such as the viscosity of the resist material and the film thickness to be applied. Then, the rotational force of the second motor 24 is
5, second pulley 26, belt 27, first pulley 23
Is transmitted to the rotary block 22 via the rotary shaft, and the rotary block 22 rotates.

When the rotary block 22 is rotated, the second container 12 and the vacuum suction unit 30 fixed to the rotary block 22 are integrally rotated. Further, the first container 11 is pressed by the second container 12 by the elevation drive unit 14 and is rotatable via the bearing 18, so that the first container 11 rotates integrally with the second container 12. Will be.

As a result, the wafer 4 and the processing container 10, which are vacuum-sucked by the vacuum suction portion 30, rotate integrally, and the peripheral space in the processing container 10 rotates with the wafer 4 in the same direction at the same speed. It will be.

Here, the main reason why the resist material cannot be reliably applied to the peripheral portion of the large-diameter wafer 4 as compared with the prior art is that when the wafer 4 is rotated at a high speed, the peripheral portion of the wafer 4 and its surrounding space are This is because the difference in speed becomes extremely large. According to the apparatus of the present embodiment, as described above, the surrounding space is also integrally rotated together with the wafer 4.
Since the speed difference becomes zero and evaporation of the resist material at the peripheral portion of the wafer 4 is suppressed, even if the wafer 4 has a large diameter, the resist material can be surely applied to the peripheral portion. In this spin coating process, excess resist material on the wafer 4 wraps around the wafer from the periphery to the back side,
The back surface of the wafer 4 will be contaminated. However, in the present embodiment, the resist material is prevented from being scattered inward in the radial direction from the vacuum suction portion 30 due to the presence of the vacuum suction portion 30.

After executing the coating operation for a predetermined time, the driving of the second motor 24 is stopped and the elevating and lowering drive unit 14 is driven to raise the first container 11 to the position shown by the chain double-dashed line in the figure. The processing container 10 is released. Thereafter, by driving the elevation drive unit 33 attached to the lower base 1 and raising the first motor 36, the spin chuck 31 is raised while the wafer 4 is being sucked, and the wafer 4 is removed from the processing container 10. It is taken out and set at the position indicated by the two-dot chain line in the figure. In this state, a cleaning device (not shown) for cleaning the back surface of the wafer 4 is moved to the back surface side of the wafer 4 and the first motor 36 is driven to perform the back surface cleaning while rotating the wafer 4. ,
It will shift to the subsequent processing steps. In this back surface cleaning step, the wafer 4 is held only by the spin chuck 31. The position at which the back surface of the wafer 4 is held by the spin chuck 31 is inside the position at which the wafer 4 is supported during rotation coating (the position at which the wafer 4 is supported by the vacuum suction unit 30). Therefore, in the back surface cleaning step, the position held by the vacuum suction unit 30 during the spin coating is exposed, and it is possible to remove the resist material that has wrapped around this area during the spin coating. Thus, when the wafer 4 is subsequently transferred or processed in the next step, the wafer 4
It is possible to prevent the transfer arm, the susceptor, and the like from being contaminated by the resist material attached to the back surface of the substrate.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

In the above-mentioned embodiment, a so-called nozzle scan system is adopted as the coating material dropping portion, which is capable of moving and scanning inside and outside the upper region of the wafer 4. Instead of this, it is also possible to adopt a fixing method in which the dripping part is fixed to the center of the first container 11.

In addition, in the above-described embodiment, in addition to the conventional spin chuck 31, the vacuum suction unit 30 is provided in the second container 1.
2 and is rotatable together with the processing container 10 and the wafer 4.
Are excellent in that they have the same rotational speed, but are not necessarily limited to this configuration. For example, without providing the vacuum suction unit 30, the suction and rotation of the wafer 4 in the processing container 10 can be performed by the spin chuck 31. In this case, it would be difficult to make the rotational speed of the surrounding space physically the same as that of the driving source, but at least the relative speed difference is greatly reduced as compared with the conventional one, so that the same The effects of the invention can be achieved. Further, in the above-described embodiment, the rotation driving mechanism 40 of the processing container 10 is of a pulley or belt type, but it is needless to say that various other rotation driving means can be used. Further, the coating device to which the present invention is applied is not limited to coating a resist on a semiconductor wafer, but can be applied to various coating devices such as a resist coating on a mask. Since it becomes possible, an excellent effect can be exhibited also in application to a square wafer such as a liquid crystal screen.

[0044]

According to the invention of the first aspect of the invention,
In the back surface cleaning step, since the back surface of the material to be coated is supported at a position inside the spin coating, even if the coating material wraps around within the support area of the material to be coated during spin coating, this portion should be covered during the back surface cleaning. It can be exposed and washed.

According to the inventions of claims 1 and 2, since the material to be coated and the processing container rotate in the same direction, the rotation of the material to be coated and the processing container can be prevented. The relative speed difference becomes small, the evaporation amount can be reduced, and the usage amount of the coating material can be reduced.

Particularly, in the invention of claim 2,
The material to be coated can be easily and closely supported on the processing container side, and the contact portion prevents the coating material from scattering and adhering inward in the radial direction from the contact portion area on the back surface of the material to be coated during spin coating. it can.

According to the third aspect of the invention, since the material to be coated is held only by the holding means, in the back surface cleaning step, the contact portion at the time of spin coating is in contact. The back surface area of the material is exposed, and the coating material that has circulated to this area can be reliably removed, and then, when the material to be coated is transported or is processed in the next step, it is possible to prevent contamination of the support portion and the like. .

According to the invention of the fourth aspect, the first rotation driving means can integrally rotate the material to be coated and the processing container, so that the processing container is rotated in the same direction together with the material to be coated. In this case, the relative speed difference between the rotation of the processing container and the material to be coated is reduced, and evaporation of the material to be coated having a large diameter is suppressed at the peripheral portion. Also, since the amount of evaporation can be reduced,
The amount of the coating material to be dropped on the coating material can be reduced reflectively.

According to the invention of claim 5, the coating material adhesion preventing means exposes the back surface region of the coating material to which the contact portion at the time of spin coating was in contact, and the area around this region is exposed. It is possible to reliably remove the dented coating material.

[0050]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 4 Coating Material 10 Processing Container 11 First Container 12 Second Container 14 Second Rotation Drive Unit 30 Vacuum Suction Unit (Contact Unit) 31 Spin Chuck (Holding Unit) 40 First Rotation Drive Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Omori Den 5-3-6 Akasaka, Minato-ku, Tokyo Tokyo Electron Co., Ltd.

Claims (5)

[Claims] 1. A coating method for applying a coating material by rotating the coating material, wherein the back surface of the coating material is held by a holding portion, and the treatment is performed by relative movement of the holding portion and a processing container. A step of arranging the material to be coated in a container, and bringing the back surface of the material to be coated into contact with the processing container at a position outside the holding position of the holding part, and A rotation coating step of integrally rotating the coating material in the same direction to form a coating film by the coating material supplied to the surface of the coating material, and a back surface of the coating material having the coating film formed thereon. And a back surface cleaning step of cleaning the back surface of the material to be coated by holding it by a holding section and rotating the holding section. 2. A processing container having an opening formed in the center and an abutting portion arranged around the opening, a shaft portion extending upward through the opening, and a holding member formed at an upper end of the shaft portion. When applying the coating material to the surface of the material to be coated using a coating device having a holding unit having a section, the holding section is arranged above the processing container to hold the back surface of the material to be coated. A step of holding the coating material, and a step of relatively moving the holding portion holding the coating material and the processing container, and bringing the back surface of the coating material into contact with the contact portion of the processing container. The step of bringing the back surface of the material to be coated into close contact with the contact portion by the holding force of the holding means, and rotating the processing container integrally with the material to be coated in the same direction to form a surface of the material to be coated. Coating film on the coated material by the supplied coating material A spin coating step of forming, subsequently, while rotating the coating the film is formed the coating material, the back surface cleaning step for cleaning the back surface of the object to be coated material,
And a coating method. 3. The back surface cleaning step according to claim 2, wherein the holding means holds the coated material and the holding means rotates the coated material. Application method. 4. A coating device for supplying a coating material to the surface of a coating material and rotating the coating material to form a coating film on the surface by the coating material, wherein an opening formed at the center A processing container having a contact portion arranged around the opening, and a holding means having a shaft portion extending upward through the opening and a holding portion for the coated material provided at an upper end of the shaft portion. An elevating means for moving the processing container and the holding part relative to each other to bring the coated material into contact with the contact portion; and the coated material contacting the contact portion. First rotation driving means for rotating the processing container to integrally rotate the processing container and the material to be coated to form the coating film; and holding the material to be coated having the coating film formed thereon. Second rotation driving means for rotating the holding portion, A cleaning device for cleaning the back surface of the material to be held and rotated, the coating device. 5. The abutting portion according to claim 4, wherein the coating material scattered from the coating material during spin coating is the contact area of the back surface area of the coating material. A coating device which is also used as a coating material adhesion preventing means for preventing adhesion to an inner region.