JP2011036847A - Film-forming method and spin coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film-forming method which removes the swell of a peripheral part of a substrate to form a film having a uniform film thickness, and a spin coater. <P>SOLUTION: In the film-forming method, the film is formed on the surface of the substrate 5. The film-forming method comprises a film arranging process of arranging a coating liquid 21 to form a film on the upper surface of the substrate 5, a substrate-rotating process of rotating the substrate 5 about a predetermined axis, and an air-spraying process of spraying air to the upper-surface peripheral part of the substrate from the upper part of the substrate 5. In the air-spraying process, air is sprayed from the central part of the substrate 5 toward the outside of the substrate. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a coating film forming method and a spin coater, and more specifically to a method for forming a coating film having a uniform film thickness on a substrate surface and a spin coater used in such a method.

  Conventionally, display materials, video display fields such as functional films, information recording fields such as magnetic tapes, paper fields such as ink-jet paper, electrical and telegraph related fields such as thin film batteries and electronic circuit boards, and optics such as low-pass filters The so-called spin coating method is employed to form a film with a uniform thickness on the surface of a substrate such as a substrate in many fields such as the related field, the functional fiber field such as water repellency, waterproofing and deodorization. . In this spin coating method, a substrate on which a coating liquid for forming a coating film is arranged is fixed on a stage that is rotationally driven, and this stage is rotated to use centrifugal force generated by the rotation of the stage. Spread the coating liquid. In the spin coating method, the film thickness is adjusted by adjusting the rotation speed and rotation time of the stage.

  When such a spin coating method is used, the film thickness can be made uniform with high accuracy at the center of the film close to the rotation axis of the stage, but at the peripheral edge of the substrate far from the rotation axis of the stage, There has been a problem that the thickness of the film becomes thicker than the central part. That is, when the coating liquid is spread by centrifugal force, the coating liquid flows from the center of the substrate toward the peripheral portion, and the coating liquid is collected at the peripheral portion of the base material. While the stage is rotating, the coating liquid collected at the peripheral edge of the base material is scattered from the peripheral edge of the base material to the outside of the stage by centrifugal force, but when the rotation of the stage is stopped, This is because the coating liquid concentrates on the peripheral edge of the substrate due to the surface tension.

Especially in optical fields such as low-pass filters,
Since high-precision film thickness is required, it is necessary to suppress the error in film thickness to about ± several μm with respect to the desired thickness. Since the thickness is several tens of μm or more, the error cannot be suppressed to about ± several μm.

  As means for solving this problem, the spin coating method described in Patent Document 1 is known. Specifically, in the spin coating method described in Patent Document 1, while spreading or spreading the coating liquid, from the lower side of the substrate placed on the stage toward the lower surface of the substrate. Air is blown to create a flow of air from the center of the substrate toward the periphery of the substrate. And according to Patent Document 1, by creating an air flow from the central part of the base material toward the peripheral part of the base material, a negative pressure is generated further outside the peripheral part of the base material, and the peripheral edge of the base material The coating liquid collected in the part is pulled toward the outside of the substrate.

JP 2004-164727 A

  However, in the spin coating method described in Patent Document 1, the rising of the peripheral edge of the substrate is eliminated by using a negative pressure generated by the air flowing from the lower side of the substrate toward the outer side of the substrate. Therefore, for example, when the thickness of the film is to be made relatively thick, the force for pulling the coating liquid is not sufficient, and the swell of the peripheral portion of the substrate cannot be eliminated. As a result, in the spin coating method described in Patent Document 1, the swell cannot be eliminated depending on the thickness of the film to be formed and the viscosity of the coating liquid to be used. There was a problem that it could not be formed.

Therefore, the present invention provides
It was made in order to solve the above-mentioned problems, and removes the bulge generated at the peripheral edge of the base material regardless of the thickness of the film to be formed and the viscosity of the coating liquid to be used. It is an object of the present invention to provide a coating film forming method capable of forming a coating film having a spin coater and a spin coater used in such a coating film forming method.

  In order to solve the above-mentioned problems, the present invention is a coating film forming method for forming a coating film on the surface of a substrate, and a coating film arrangement for arranging a coating liquid for forming a coating film on the upper surface of the substrate A step of rotating the base material around a predetermined axis, and an air blowing step of blowing air from the upper part of the base material to the upper peripheral edge of the base material, Air is blown along the direction from the center of the substrate toward the outside of the substrate.

  According to the present invention thus configured, the thickness of the coating liquid disposed on the upper surface of the base material is made substantially uniform by the base material rotation step, and then the air spraying step is performed. And in the air spraying step, the coating liquid at the peripheral edge of the base material is directed toward the outside of the base material by spraying air from the center of the base material toward the outside of the base material. Can fly along. As a result, the bulge formed on the peripheral edge of the substrate can be removed, and the thickness of the coating liquid can be made uniform in the central portion and the peripheral portion of the coating liquid.

  Preferably, in the present invention, in the air blowing step, air is blown onto the lower surface of the substrate along the direction from the center of the substrate toward the outside of the substrate at the same time as air is blown onto the upper surface of the substrate. .

  According to the present invention thus configured, the coating liquid blown from the upper surface of the base material by blowing air to the lower surface of the base material at the same time as the air is sprayed on the upper surface of the base material It is possible to prevent wrapping around the lower surface of the sheet.

  The present invention also provides a spin coater for forming a coating film on the surface of a substrate, a stage for holding the substrate on which the coating film is formed and rotating the substrate around a predetermined axis, An upper air blowing portion that blows air from the top of the material to the peripheral edge of the upper surface of the substrate, and the upper air blowing portion blows air along the direction from the center of the substrate toward the outside of the substrate It is characterized by that.

  According to the present invention configured as above, the thickness of the coating liquid disposed on the upper surface of the substrate is made substantially uniform by rotating the stage, and then air is sprayed onto the coating liquid by the upper air spraying unit. . Then, the upper air spraying part blows air to the upper surface peripheral part of the base material along the direction from the center part of the base material to the outside of the base material, thereby raising the bulge formed on the peripheral part of the base material. Can be blown toward the outside of the material. As a result, the swell of the peripheral portion of the substrate can be removed, and the thickness of the coating liquid can be made uniform in the central portion and the peripheral portion of the coating liquid.

  In the present invention, it is preferable to further include a lower air blowing portion that blows air onto the lower surface of the base material along a direction from the center of the base material toward the outside of the base material.

  According to the present invention configured as above, air can be blown to the lower surface of the base material at the same time as air is blown to the upper surface of the base material. It is possible to prevent wrapping around the lower surface of the base material.

  Moreover, preferably in this invention, an upper air spraying part has a disk shape, and is provided with the blower outlet formed along the outer periphery whole periphery.

  According to the present invention thus configured, the bulge formed on the entire periphery of the base material can be simultaneously removed by the air outlet formed along the entire outer periphery of the upper air spraying unit, Efficiency can be improved.

Preferably, in the present invention, the lower air blowing section includes a cylindrical body that surrounds the stage with a predetermined interval between the stage and an air flow path formed between the cylindrical body and the stage. Is sprayed onto the lower surface of the substrate.

  In the present invention, preferably, the upper air blowing portion is configured by a tubular member having a tip disposed toward the upper surface of the substrate.

  In the present invention, preferably, the lower air blowing portion is configured by a tubular member whose tip is disposed toward the lower surface of the substrate.

According to the present invention configured as described above, air is blown to the upper surface of the substrate by the tube-shaped upper air blowing portion whose tip is disposed toward the substrate while rotating the stage. The bulge formed at the peripheral edge can be removed. Thereby, the thickness of the coating liquid can be made uniform in the central portion and the peripheral portion of the coating liquid.
Also, at the same time as air is blown onto the upper surface of the base material, air is blown from the lower air spraying part to the lower surface of the base material, so that the coating liquid blown from the upper surface of the base material wraps around the lower surface of the base material. Can be prevented.

As described above, according to the present invention, it is possible to sufficiently remove the bulge generated at the peripheral edge of the base material and form a coating film having a uniform film thickness.

It is sectional drawing which shows the outline of the spin coater concerning the 1st Embodiment of this invention. It is sectional drawing to which some spin coaters of FIG. 1 were expanded. It is sectional drawing which shows the outline of the spin coater concerning the 1st Embodiment of this invention, and is a figure for demonstrating the coating-film formation method using a spin coater. It is sectional drawing which shows the outline of the spin coater concerning the 1st Embodiment of this invention, and is a figure for demonstrating the coating-film formation method using a spin coater. It is sectional drawing which shows the outline of the spin coater concerning the 1st Embodiment of this invention, and is a figure for demonstrating the coating-film formation method using a spin coater. It is sectional drawing which shows the outline of the spin coater concerning the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. In the following embodiments, the coating film forming method and the spin coater according to the present invention will be described as being used for manufacturing an optical low-pass filter. In addition, this invention is not limited to this embodiment, It is applicable also to the other use which needs to form the coating liquid of uniform thickness on the surface of a base material.

  The low-pass filter manufactured in this embodiment is an optical component used to suppress moire in an imaging system such as a digital camera. This low-pass filter is manufactured by curing a uniform coating film of a liquid photopolymerizable composition formed on a substrate with ultraviolet rays or the like. In this manufacturing process, when the coating film is cured by ultraviolet rays or the like, a photomask is disposed on the coating film at a predetermined interval, and therefore, the thickness of the coating film is required to be within a range of error ± several μm.

  In the coating film formation in this low-pass filter manufacturing method, a liquid photopolymerizable composition is supplied to the surface of the substrate, this substrate is placed on a spin coater stage and rotated, and the photopolymerizable composition is placed on the surface of the substrate. And a coating film is formed on the substrate surface. In addition, as a photopolymerizable composition, the photopolymerization composition containing polyfunctional monomers, such as a (meth) acryl monomer containing a (meth) acryloyl group, a vinyl group, an allyl group, is used. Then, the photopolymerizable composition in the peripheral part of a base material is removed with the air blown from the blower outlet of the air nozzle, and the coating film of uniform thickness is obtained.

  Next, a photomask is placed on the photopolymerization composition coating film with a gap of, for example, about 100 μm, and the photopolymerization composition coating film is irradiated with ultraviolet rays to cure the photopolymerizable composition at the irradiated site. Let As the ultraviolet rays, those having parallel light and a substantially constant light intensity distribution are preferable. Next, with the photomask removed, the photopolymerizable composition is again irradiated with ultraviolet rays to further cure the photopolymerizable composition. By such a process, a molded body having a columnar structure having a different refractive index, which is used as a low-pass filter or the like that can suppress moire, is formed.

  Next, the coating film formation performed during the low-pass filter manufacturing process will be described in detail. FIG. 1 is a cross-sectional view showing an outline of a spin coater according to a first embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a part of the spin coater of FIG.

First, as shown in FIG. 1, the spin coater 1 includes a stage 3 that is driven to rotate about a predetermined axis. The stage 3 includes a flat circular plate 7 for arranging the base material 5 to be processed and a columnar column 9 for supporting the circular plate 7. The stage 3 is rotationally driven around the axis of the support column 9 by a driving means (not shown) such as a motor. The base material 7 is provided with a vacuum chuck (not shown). The vacuum chuck fixes the base material 5 disposed on the upper surface of the circular plate 7 on the circular plate 7.
For spin coaters for coating a substrate with a hole in the center of a DVD, etc., a center pin is provided at the center of the stage, and the substrate is fixed to the stage using this center pin. It is good also as composition to do.

  In addition, the spin coater 1 includes an air nozzle 11 provided on the upper side of the stage 3 and an air blowing cylinder 13 provided on the lower side of the stage 3. The air nozzle 11 is fixed above the stage 3 so that the center of the air nozzle 11 overlaps the rotation axis of the stage 3. The air nozzle 11 includes an air inlet 15 formed in the center and a blower outlet 17 formed along the entire outer periphery of the air nozzle 11. The inlet 15 and the blower outlet 17 communicate with each other. . Moreover, the outer periphery vicinity of the disk-shaped air nozzle 11 is bent toward the lower side, and the blower outlet 17 opens toward the outer circumferential direction lower side of the air nozzle 11.

  The air blowing cylinder 13 is arranged with a predetermined distance from the support column 9 of the stage 3, and has a cylindrical shape surrounding the radially outer side of the support column 9 of the stage 3. And between the support | pillar 9 and the circular board 7 of the stage 3, and the air blowing cylinder 13, the air flow path 19 is formed over the perimeter. Further, an air introduction port (not shown) is provided below the air blowing cylinder 13. When air is introduced into the air blowing cylinder 13 from the air introduction port, the air is supplied to the wall of the air blowing cylinder 13. And flows upward through a flow path 19 provided between the columns 9 of the stage 3. The air flows between the circular plate 7 of the stage 3 and the air blowing cylinder 13 toward the radially outer side of the circular plate 7 of the stage 3.

  Next, the spin coater 1 will be described in more detail with reference to FIG. As shown in FIG. 2, the air nozzle 11 is configured such that the air blowing direction from the air outlet 17 is an angle α with respect to the perpendicular A on the upper surface of the substrate 5 so that the air flows from the center of the substrate 5 toward the periphery. It is comprised so that it may make. This angle α is an acute angle, more specifically, preferably 45 to 80 degrees, more preferably 60 to 80 degrees, and even more preferably 70 to 80 degrees. By setting the angle α to the above range, it is possible to prevent the coating liquid from flowing toward the center side of the substrate 5 when air hits the coating liquid.

  Further, the width S of the air outlet 17 of the air nozzle 11 is set to 0.1 mm to 0.15 mm, for example. Moreover, it is preferable that the distance L1 from the lower end of the blower outlet 17 to the upper surface of the base material 5 is set to 0.5 mm thru | or 2.0 mm. By setting the distance L1 in this way, it is possible to prevent the wind speed of the air blown out from the air nozzle 11 from decreasing before reaching the coating liquid and reducing the removal effect. In addition, the air nozzle 11 is preferably arranged so that the distance L2 between the position where the air from the air outlet 17 hits the base material 5 and the edge of the base material 5 is 1 mm to 5 mm. The distance L3 between the base material 5 and the air blowing cylinder 13 is preferably set to 0.1 mm to 0.15 mm. By setting the distance L3 in this way, it is possible to prevent the coating liquid removed from the base material 5 from entering the flow path 19. Moreover, it is preferable that the wind speed of the air which blows off from the blower outlet 17 of the air nozzle 11 is set so that it may become 30 m / s thru | or 400 m / s.

  In addition, each said value can be suitably changed according to the viscosity of a coating liquid, the thickness of the coating film to form, etc.

  Next, a coating film forming method using the spin coater 1 will be described in detail with reference to FIGS. Here, FIG. 3 to FIG. 5 are cross-sectional views showing an outline of the spin coater, and are diagrams for explaining a coating film forming method using the spin coater.

  In the coating film formation method in this embodiment, first, the coating liquid 21 for forming a coating film is arrange | positioned on the upper surface of the base material 5. FIG. At this time, the coating liquid 21 is disposed in the vicinity of the center of the circular plate 7 of the stage 3. Next, the stage 3 is rotated around the axis. As a result, the coating liquid disposed in the vicinity of the central portion of the circular plate 7 of the stage 3 is spread by the centrifugal force and spreads around the peripheral portion of the circular plate 7. When the rotation of the stage 3 is stopped, as shown in FIG. 4, the thickness of the coating liquid in the vicinity of the center portion of the circular plate 7 of the stage 3 becomes a desired thickness. On the other hand, a bulge is formed near the peripheral edge of the circular plate 7 of the stage 3 due to the surface tension of the coating liquid 21.

  Next, air is blown onto the base material 5 from the lower side of the base material 5 by the air blowing cylinder 13 at the same time as air is blown onto the upper surface of the base material 5 by the air nozzle 11. And the coating liquid which exists in the circumferential direction outer side of the circular board 7 rather than the position where air hits the circular board 7 with the air sprayed on the upper surface of the base material 5 from the air nozzle 11 can be blown out of the circular board 7. At this time, since the air outlet 11 of the air nozzle 11 is provided over the entire circumference of the air nozzle 11, the coating liquid in the vicinity of the peripheral edge of the circular plate 7 can be simultaneously blown over the entire circumference.

  Thereby, as shown in FIG. 5, the coating liquid at the peripheral edge of the circular plate 7 and the coating liquid under the swelling can be removed from the base material 5. As a result, a circular coating film having a uniform thickness and a diameter obtained by subtracting the width of the removed peripheral portion from the diameter of the substrate 5 can be formed on the substrate 5.

  At this time, by spraying air from the lower side of the circular plate 7 by the air blowing cylinder 13, the coating liquid splashed from the upper surface of the circular plate 7 wraps around the edge of the circular plate 7 and the side portion of the circular plate 7. It can be prevented from adhering to the flow path or entering the flow path 19.

In addition, it is preferable that the air is blown from the air nozzle 11 after the coating liquid is formed on the entire surface by rotating the stage 3 to the peripheral edge. This is because if the air is blown before the coating liquid spreads to the peripheral edge, the coating film is not formed well by the air. When air is blown after the coating film is formed, the stage 3 may be stopped, or the stage 3 may be rotated. When spraying while rotating, if the rotational speed of the stage 3 is too high, the film thickness becomes thinner than the desired film thickness. Therefore, the rotational speed needs to be sufficiently slower than the rotational speed at which the coating film is formed.
Note that it is preferable to start the air blowing by the air blowing cylinder 13 not only after the coating film is formed, but while the coating liquid 21 is spread by rotating the stage 3. Thereby, while spreading the coating liquid 21, it is possible to prevent the coating liquid 21 from entering the flow path 19 around the edge of the circular plate 7.

  Next, a second embodiment of the present invention will be described in detail. Since the spin coater according to the second embodiment has the same configuration as the spin coater 1 according to the first embodiment described above, detailed description thereof is omitted, and there is a difference. Only a detailed explanation.

  FIG. 6 is a cross-sectional view showing a spin coater according to the second embodiment. As shown in FIG. 6, the spin coater 31 includes tube-shaped air blowing portions 33 and 35 on the upper side and the lower side of the circular plate 7 of the stage 3, respectively.

  Unlike the above-described air nozzle 11 and air blowing cylinder 13, the upper air blowing portion 33 and the lower air blowing portion 35 blow air to one point of the base material 5 instead of the entire circumference of the base material 5. .

  Furthermore, it is preferable that the upper air blowing portion 33 and the lower air blowing portion 35 are arranged in the same straight line from the center of the substrate 5. If the air blowing portions are not in the same straight line, the effect of the air in the lower air blowing portion that prevents wraparound when removed by the upper air blowing portion may be lost.

  Further, the air outlet 37 of the upper air outlet 33 is configured such that the air blowing direction forms an angle α with the perpendicular A on the upper surface of the circular plate 7 as described above. The angle α is an acute angle, and more specifically, is preferably 45 to 85 degrees, more preferably 60 to 85 degrees, and still more preferably 70 to 80 degrees. By setting the angle α to the above range, it is possible to prevent the coating liquid from flowing toward the center side of the substrate 5 when air hits the coating liquid.

The distance L4 between the lowermost surface of the air outlet 37 of the upper air outlet 33 and the upper surface of the substrate 5 is preferably set to 0.5 mm to 2.0 mm. By setting the distance L4 in this way, it is possible to prevent the wind speed of the air blown out from the upper air blowing portion 33 from being lowered before reaching the coating liquid, thereby reducing the removal effect. Moreover, it is preferable to arrange | position so that the distance L5 of the front end surface of the blower outlet 33 of the upper side air blowing part 33 and the edge of the base material 5 may be set to 1 mm thru | or 5 mm.

  The distance L6 from the uppermost surface of the air outlet 39 of the lower air outlet 35 to the lower surface of the substrate 5 is preferably set to 0.5 mm to 2.0 mm. By setting the distance L6 in this way, it is possible to prevent the effect for preventing the coating liquid blown off from the upper air blowing portion 33 from flowing around the back surface of the base material 5 from decreasing. Moreover, it is preferable to install so that the distance L7 of the front end surface of the blower outlet 39 of the lower air blowing part 35 and the edge of the base material 5 may be set to 1 mm to 2 mm.

  It is preferable that the wind speed of the air blown out from the upper air outlet 37 and the lower air outlet 39 is set to be 30 m / s to 400 m / s.

  Depending on the location of the upper air blowing part 33 and the lower air blowing part 35, even if the wind speed at the blower outlet is the same, there is a possibility that the balance between the removal of the upper surface and the air to prevent the lower surface from flowing out may not be achieved. What is necessary is just to adjust the wind speed of the air of upper side and lower side.

In addition, each said value can be suitably changed according to the viscosity of a coating liquid, the thickness of the coating film to form, etc.

And when forming a coating film on the base material 5 using such a spin coater 31, after rotating the stage 3 and spreading a coating liquid and forming a coating film, the rotational speed of the stage 3 is made into about 10 rpm thru | or 100 rpm. While rotating at a slow speed, air is blown onto the base material 5 simultaneously from the upper air blowing portion 33 and the lower air blowing portion 35 only while the base material 5 is rotated once to three times. In addition, since the rotational speed of the stage 3 will become still thinner than the coating film of a desired film thickness if it is too fast, it needs to be a rotational speed sufficiently slower than the rotational speed at which the coating film is formed.
The air blowing by the lower air blowing portion 35 may be performed while the stage 3 is rotated to form a coating film. Thereby, wraparound while spreading the coating liquid can be prevented.

  In this way, even if the bulge is removed while rotating the stage 3 using the tubular upper air blowing portion 33 and the lower blowing portion 35, the uniform thickness as described above is formed on the substrate 5. This film can be formed.

  Next, examples of the present invention will be described.

  In this example, the present coating film forming method was performed using a glass plate having a diameter of 120 mm and a thickness of 0.7 mm (product name: D263, manufactured by Ceratech Japan Co., Ltd.) as a base material. In the following description, “parts” indicates parts by mass.

  As the coating liquid to be disposed on the substrate, 25 parts of polyoxytetramethylene glycol dimethacrylate (trade name: Acryester PBOM, manufactured by Mitsubishi Rayon Co., Ltd.), 2,2 bispropane (Daiichi Kogyo Seiyaku Co., Ltd.) Manufactured, trade name: New Frontier BPEM-10) 30 parts, phenol ethyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd., trade name: New Frontier PHE), urethane acrylate composition (Daiichi Kogyo Seiyaku Co., Ltd.) , Trade name: GX-8862V) and 35 parts of 1-hydroxy-cyclohexyl-phenyl-ketone (Ciba Specialty Chemicals, trade name: IRGACURE 184) mixed. The viscosity of the coating liquid at 20 ° C. was 1100 mPa · s.

Example 1
(1) Installation of air nozzle The spin coater detailed in Embodiment 1 (see FIG. 1) was used. At this time, an air nozzle having a slit width of 0.1 mm and an angle in the air blowing direction of 60 degrees with respect to a normal to the upper surface of the base material was used. The distance between the air nozzle and the substrate was set to 0.5 mm, and the distance between the position where the air blown from the air nozzle hits the substrate and the edge of the substrate was set to 5 mm.

(2) Formation of coating film After fixing the substrate on the spin coater stage as described above by vacuum suction, about 50 ml of coating solution is dropped near the center of the coating surface using a dropper, and the air blown out from the air blowing cylinder The wind speed was adjusted to 30 m / s. Then, the stage was rotated at 600 rpm for 30 seconds while air was blown out from the air blowing cylinder, and the film thickness was controlled to be 70 μm.

  After stopping the rotation of the stage, the air speed of the air blown from the air nozzle is set to be about 200 m / s, and further the air speed of the air blown from the air blowing cylinder is set to be 50 m / s, At the same time, air was blown onto the substrate for 30 seconds by an air blowing cylinder.

  As a result, a circle having a diameter of about 110 mm and a film thickness of 70 μm was formed on the substrate. The bulge between the central portion and the peripheral portion formed by the air was about 5 μm thicker than the desired film thickness. Moreover, the coating liquid did not adhere to the lower surface of the substrate.

(Comparative Example 1)
The processing was performed in the same manner as in Example 1 except that the processing with air after the stage rotation was stopped was not performed.

  As a result, a coating film was formed on the entire surface of the substrate, the film thickness of the central portion of the coating film was 70 μm, and no coating liquid adhered to the lower surface of the substrate. However, a bulge thicker than the desired film thickness by 40 μm was formed at the peripheral edge of the coating film.

(Example 2)
(1) Installation of air nozzle In Example 2, the spin coater detailed in Embodiment 2 was used. At this time, a special needle (needle model: SNA-18G) manufactured by Musashi Engineering Co., Ltd. is used for the upper air blowing portion and the lower air blowing portion, and the angle of the air blowing direction is perpendicular to the upper surface of the base material. The one subjected to bending so as to be 80 degrees was used. The distance between the lowermost surface of the air outlet of the upper air outlet and the upper surface of the substrate is 0.5 mm, and the distance between the uppermost surface of the air outlet of the lower air outlet and the lower surface of the substrate is 0.5 mm. . Furthermore, the distance between the front end surface of the air outlet of the upper and lower air outlets and the edge of the substrate was set to 2 mm.

(2) Formation of coating film After fixing the substrate on the stage of the spin coater by vacuum adsorption, about 50 ml of coating solution is dropped near the center of the coating surface using a dropper, and while rotating the stage at 600 rpm for 30 seconds, The film thickness was 70 μm.

  Next, after rotating at 600 rpm for 30 seconds, the stage was rotated at 10 rpm for 20 seconds, and the air speed of the air blown out from the upper and lower air blowing portions was set to about 200 m / s and air was blown.

As a result, a circle having a diameter of about 110 mm and a film thickness of 70 μm was formed on the substrate. The bulge between the central portion and the peripheral portion formed by air was in a state of about 3 μm thicker than the desired film thickness. Moreover, the coating liquid did not adhere to the lower surface of the substrate.
(Comparative Example 2)
The same processing as in Example 2 was performed except that air was not blown from the lower air blowing portion of the upper and lower air blowing portions.

  As a result, a coating film was formed on the entire surface of the substrate, the film thickness of the central portion of the coating film was 70 μm, and no coating liquid adhered to the lower surface of the substrate. However, a bulge thicker than the desired film thickness by 40 μm was formed at the peripheral edge of the coating film.

1,31 Spin coater 3 Stage 5 Base material 11 Air nozzle 13 Air blowing cylinder

Claims (7)

A coating film forming method for forming a coating film on a substrate surface,
A coating film arranging step of arranging a coating liquid for forming a coating film on the upper surface of the substrate;
A base material rotating step of rotating the base material around a predetermined axis;
An air blowing step of blowing air from the upper part of the base material to the upper surface peripheral part of the base material,
In the air blowing step, air is blown along the direction from the center of the base material toward the outside of the base material;
A method of forming a coating film characterized by   In the air blowing step, at the same time as air is blown onto the upper surface of the substrate, air is blown onto the lower surface of the substrate along the direction from the center of the substrate toward the outside of the substrate. The coating-film formation method of description. A spin coater for forming a coating film on a substrate surface,
A stage for holding a substrate on which a coating film is formed and rotating the substrate around a predetermined axis;
An upper air blowing part for blowing air from the upper part of the base material to the upper surface peripheral part of the base material,
The upper air blowing portion blows air along a direction from the central portion of the base material toward the outside of the base material.
A spin coater characterized by   4. The spin coater according to claim 3, further comprising a lower air blowing portion that blows air onto a lower surface of the base material along a direction from the center of the base material toward the outside of the base material.   4. The spin coater according to claim 3, wherein the upper air spraying portion has a disk shape and includes an air outlet formed along the entire outer periphery thereof.   The lower air blowing section includes a cylindrical body that surrounds the stage with a predetermined interval between the lower air blowing section, and the air is supplied to the base via a flow path formed between the cylindrical body and the stage. The spin coater according to claim 4, wherein the spin coater is sprayed onto a lower surface of the material.   4. The spin coater according to claim 3, wherein the upper air blowing portion and / or the lower air blowing portion is configured by a tubular member having a tip disposed toward an upper surface and / or a lower surface of the base material.

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