JP2014014794A - Coating film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating film forming method capable of preventing deposition of coating agent on an undersurface and side surfaces of an outer peripheral edge section of a substrate with high versatility.SOLUTION: A coating film forming method includes: a first protective film sticking process for sticking a first protective film 20 to an upper surface 12 of a substrate 10 so that an outer peripheral edge section 22 of the first protective film 20 protrudes from an outer peripheral edge of the substrate 10; a second protective film sticking process for sticking a second protective film 30 to an undersurface 13 of the substrate 10 so that an outer peripheral edge section 32 of the second protective film 30 protrudes from the outer peripheral edge of the substrate 10; a film sticking process for sticking the outer peripheral edge section 22 of the first protective film 20 and the outer peripheral edge section 32 of the second protective film 30 together; an application process for applying coating agent by a spin coat method after the film sticking process; and a film peeling process for peeling the first protective film 20 and the second protective film 30 from the substrate 10 after the application process.

Description

  The present invention relates to a coating film forming method, and more particularly to a technique for forming a coating film on a substrate by spin coating (rotary coating).

Conventionally, a spin coating method is known as one of methods for forming a coating film on a substrate. In the spin coat method, a coating agent containing the material constituting the coating film is dropped onto the top surface of the substrate rotated at high speed, and the coating agent is spread on the top surface of the substrate by centrifugal force to form a coating film with a uniform thickness. To do.
By the way, when forming a coating film on a board | substrate, it may be preferable that a coating agent does not adhere to the outer periphery part of a board | substrate. This is because the outer peripheral edge portion of the substrate easily comes into contact with the jig or the storage case when handling the substrate, and therefore, if the coating agent adheres to the outer peripheral edge portion, the jig or the storage case becomes dirty with the coating agent. This is because if the jig or the storage case becomes dirty with the coating agent, the substrate also becomes dirty due to secondary contamination.

  As one method for preventing the coating agent from adhering to the outer peripheral edge of the substrate, Patent Document 1 discloses a frame-like protection on the upper surface of the outer peripheral edge of the substrate 901 as shown in FIG. A film 902 is attached, and a coating agent 903 is applied by spin coating in that state as shown in FIG. 16 (b), and the protective film 902 is applied from the substrate 901 after application as shown in FIG. 16 (c). It is described that, by peeling, a coating film 904 is formed on the upper surface of the outer peripheral edge portion of the substrate 901 without attaching the coating agent 903 as shown in FIG.

  In Patent Document 2, as shown in FIG. 7, a block layer 912 is formed on the upper surface of the outer peripheral edge portion of the substrate 911, and block layers 913 and 914 are also formed on the lower surface and side surfaces of the outer peripheral edge portion. In this state, a coating agent is applied by spin coating, and after coating, the block layers 912 to 914 are removed by evaporation by heating or by dissolving with a solvent, and the outer peripheral edge of the substrate 911 is removed. It is described that the coating film is formed on the lower surface and the side surface as well as the upper surface of the part without adhering the splash 915 of the coating agent.

JP-A-2-170163 JP-A-6-63498

  However, although the coating film forming method described in Patent Document 1 can prevent the coating agent 903 from adhering to the upper surface of the outer peripheral edge portion of the substrate 901, the coating agent 903 splashes on the lower surface and side surfaces of the outer peripheral edge portion. It cannot be prevented until it adheres. On the other hand, the coating film forming method described in Patent Document 2 can prevent the coating agent droplets 915 from adhering to the lower surface and the side surface of the outer peripheral edge of the substrate 911, but to remove the block layers 912 to 914. Heating is required or use of a solvent is required. Therefore, since it cannot be used when applying a heat-sensitive coating agent, or cannot be used when applying a coating agent that dissolves in a solvent, the types of coating agents that can be used are limited. Poor versatility as a method for forming a coating film.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a coating film forming method that can prevent the coating agent from adhering to the lower and side surfaces of the outer peripheral edge of the substrate and has high versatility. And

  In order to achieve the above object, a coating film forming method according to an aspect of the present invention is a coating film forming method in which a coating agent is applied to a predetermined region on a substrate by spin coating to form a coating film, A first protective film having an opening provided in a region corresponding to the predetermined region and having an outer contour larger than the outer contour of the substrate is formed on the upper surface of the substrate, the predetermined region is included in the opening, and the first A first protective film application step for attaching the outer peripheral edge of the protective film so as to protrude from the outer peripheral edge of the substrate, and a second protective film having an outer contour larger than the outer contour of the substrate, on the lower surface of the substrate, A second protective film attaching step for attaching an outer peripheral edge portion of the second protective film so as to protrude from an outer peripheral edge of the substrate; the first protective film attaching step; and the second protective film attaching step. In addition, a film bonding step for bonding the outer peripheral edge portion of the first protective film and the outer peripheral edge portion of the second protective film, and after the film bonding step, the coating agent is applied to the predetermined region by a spin coating method. And a film peeling step of peeling the first protective film and the second protective film from the substrate after the coating step.

  The coating film formation method which concerns on 1 aspect of this invention bonds the outer peripheral part of the 1st protective film affixed on the upper surface of the board | substrate, and the outer peripheral part of the 2nd protective film affixed on the lower surface of the said board | substrate. After that, since the coating agent is applied by a spin coating method, it is possible to prevent the coating agent from adhering to the upper surface, the lower surface, and the side surface of the outer peripheral edge of the substrate. In addition, since the first protective film and the second protective film are removed by peeling, it is not necessary to limit the type of coating agent in consideration of the removal step, and this is a highly versatile coating film forming method.

The conceptual diagram for demonstrating the outline of the coating film formation method which concerns on 1 aspect of this invention Process drawing which shows the coating film formation method which concerns on 1 aspect of this invention The top view for demonstrating the coating film formation method which concerns on 1st Embodiment Sectional drawing for demonstrating the coating film formation method which concerns on 1st Embodiment The figure which shows the result of having measured the thickness of the outer periphery part of a coating film The figure for demonstrating the film bonding process which concerns on the modification 1. The top view for demonstrating the coating film formation method which concerns on 2nd Embodiment The figure for demonstrating the 1st protective film which concerns on the modification 2. The figure for demonstrating the 1st protective film which concerns on the modification 3. The figure for demonstrating the 1st protective film which concerns on the modification 4. FIG. 4E is an enlarged cross-sectional view showing a portion surrounded by a two-dot chain line Diagram showing the relationship between film protrusion width and particle adhesion number Diagram for explaining peeling experiment by double cantilever method The figure which shows the relationship between the bending elastic modulus of a protective film, and peeling distance The figure which shows the relationship between the thickness of a 2nd protective film, and the number of particle adhesion The perspective view which shows the coating film formation method of patent document 1 Sectional drawing which shows the coating film formation method of patent document 2

Hereinafter, a coating film forming method according to one embodiment of the present invention will be described with reference to the drawings.
<Outline of One Embodiment of the Present Invention>
A coating film forming method according to an aspect of the present invention is a coating film forming method for forming a coating film by applying a coating agent to a predetermined region on a substrate by a spin coating method, and the coating film forming method is provided in a region corresponding to the predetermined region. A first protective film having an opening and having an outer contour larger than the outer contour of the substrate is formed on the upper surface of the substrate, the predetermined region is included in the opening, and the outer peripheral edge of the first protective film is A first protective film sticking step for sticking so as to protrude from the outer peripheral edge of the substrate, and a second protective film having an outer contour larger than the outer contour of the substrate on the lower surface of the substrate. After the second protective film sticking step, the peripheral edge portion sticking out of the outer peripheral edge of the substrate, the first protective film sticking step, and the second protective film sticking step, A film laminating step for laminating the peripheral edge portion and the outer peripheral edge portion of the second protective film, an application step of applying the coating agent to the predetermined region by a spin coating method after the film laminating step, and after the application step, A film peeling step of peeling the first protective film and the second protective film from the substrate.

Moreover, in a specific aspect of the coating film forming method according to an aspect of the present invention, the opening has the same shape as the predetermined region, and the first protective film is attached to the substrate in the first protective film attaching step. Affixed to the upper surface of the substrate so that the opening and the predetermined region coincide.
Moreover, in the specific situation of the coating film formation method which concerns on 1 aspect of this invention, in the said film bonding process, the outer periphery part of a 1st protective film and the outer periphery part of a 2nd protective film are the perimeters in the circumferential direction. Paste over.

Moreover, in a specific aspect of the coating film forming method according to an aspect of the present invention, the coating agent contains an adhesive.
Moreover, in the specific situation of the coating film formation method which concerns on 1 aspect of this invention, the thickness of a said 2nd protective film is thicker than the thickness of a said 1st protective film.
Moreover, in the specific situation of the coating film formation method which concerns on 1 aspect of this invention, the said opening is a square.

<Background to the Present Invention>
An example of a substrate on which a coating film having a uniform thickness is formed by a spin coating method is a support substrate with an adhesive layer that is used during the manufacture of a flexible display device. An adhesive layer is formed as a coating film on the upper surface of the support substrate. When manufacturing a flexible organic EL display, the flexible substrate is adhered to the support substrate via an adhesive layer, so that the flatness of the upper surface is maintained, thereby enabling the device to be formed in a fine pattern on the upper surface. Become.

  It is preferable that the adhesive as the coating agent is not attached to the outer peripheral edge of the support substrate with the adhesive layer. This is because if the adhesive is attached to the outer peripheral edge, the adhesive is also attached to the jig or the storage case. In addition, the support substrate is secondarily contaminated by the adhesive attached to the jig or the storage case. For example, when particles made of an adhesive (fine adhesive mass) are placed on the upper surface of the adhesive layer due to secondary contamination, when the flexible substrate is attached from there, the particles are uneven on the upper surface of the flexible substrate. This makes it difficult to form a device with a fine pattern.

  Although the coating film forming method described in Patent Document 1 can prevent the adhesive from adhering to the upper surface of the outer peripheral edge of the substrate 901, it cannot prevent the adhesive from adhering to the lower surface and side surfaces of the outer peripheral edge. Therefore, it cannot be said that the above problem is sufficiently addressed. In particular, when applying a high-viscosity adhesive, the adhesive that is blown off by centrifugal force during spin coating easily pulls the thread and wraps around the lower and side surfaces of the support substrate. The inability to prevent adhesion can be a fatal drawback.

  In addition, in the coating film forming method described in Patent Document 1, since the portion of the protective film that protrudes from the support substrate flutters due to high-speed rotation during spin coating, the particles are rolled up by the fluttering, and on the adhesive film Problems such as particle adhesion may also occur. However, if the protrusion width of the film is narrowed in order to suppress fluttering, the pressure-sensitive adhesive is more likely to wrap around the lower and side surfaces of the outer peripheral edge of the support substrate.

  On the other hand, in the coating film forming method described in Patent Document 2, since the adhesive does not adhere not only to the upper surface of the outer peripheral edge of the substrate but also to the lower surface and side surfaces, the coating film forming method described in Patent Document 1 The problems mentioned do not occur. However, since heating is necessary to remove the block layers 912 to 914 or a solvent needs to be used, it cannot be used for applying a heat-sensitive adhesive or dissolves in the solvent. The type of pressure-sensitive adhesive that can be applied is limited because it cannot be used for the application of pressure-sensitive adhesive.

  The inventors have made extensive studies on the above problems, and have invented a coating film forming method that can prevent the coating agent from adhering to the lower surface and side surfaces of the outer peripheral edge of the substrate and has high versatility. It was. In the coating film forming method according to one embodiment of the present invention, two protective films are used to prevent the coating agent from adhering to the outer peripheral edge of the substrate. These protective films are used by being attached to the upper and lower surfaces of the substrate before applying the coating agent, and are removed by peeling after the coating agent is applied. Therefore, it is not necessary to heat or use a solvent to remove the protective film, and as a result, it is not necessary to limit the type of coating agent used in consideration of the protective film removal process. This is a high coating film forming method.

  In spite of such high versatility, the coating film forming method according to one embodiment of the present invention can prevent adhesion of the coating agent to the lower surface and side surfaces as well as the upper surface of the outer peripheral edge of the substrate. . This is because the upper surface of the outer peripheral edge portion of the substrate is protected by the first protective film attached to the upper surface of the substrate, and the lower surface of the outer peripheral edge portion of the substrate is protected by the second protective film attached to the lower surface of the substrate. Furthermore, the side surface of the outer peripheral edge of the substrate is protected by bonding the outer peripheral edge of the first protective film and the outer peripheral edge of the second protective film.

  Furthermore, in the coating film formation method which concerns on 1 aspect of this invention, since the outer periphery part of the 1st protective film and the outer periphery part of the said 2nd protective film were bonded together, it protruded from the board | substrate of the protective film as a result. The thickness of the part increases. For this reason, the protruding portion is difficult to flutter due to high-speed rotation during spin coating. And since it is the structure which bonds the outer periphery part of a 1st protective film, and the outer periphery part of a 2nd protective film, even if a film protrusion width is not wide, adhesion of the coating agent to the lower surface and side surface of an outer periphery part Can be reliably prevented. Therefore, the protruding part is more difficult to flutter. From the above, it is difficult for the particles to be rolled up, and the particles are difficult to adhere on the adhesive layer.

  In addition, as a method of obtaining the board | substrate with a coating film in which the coating agent has not adhered to the outer periphery part of a board | substrate, the coating film formation method which concerns on 1 aspect of this invention, and the coating film of patent document 1 and patent document 2 In addition to the forming method, for example, a method of physically removing the coating agent by polishing or the like from the upper surface, the lower surface, and the side surface of the outer peripheral edge of the substrate after the coating process by a spin coating method is also conceivable. However, such a method not only imposes a burden on the substrate, but also may cause powder generated by polishing or the like to adhere to the coating layer.

<First Embodiment>
In the following, as an example of a coating film forming method for forming a coating film by applying a coating agent to a predetermined region on a substrate by spin coating, an adhesive as coating agent 2 is applied to a support substrate as substrate 10. A method for forming the adhesive layer as the coating film 40 will be described. Note that the coating film forming method according to one embodiment of the present invention is not limited to the method of forming an adhesive film as the coating film, and for example, a resist may be formed as the coating film.

(Outline of coating film forming method)
FIG. 1 is a conceptual diagram for explaining an outline of a coating film forming method according to one embodiment of the present invention. In the coating film forming method according to one aspect of the present invention, first, as shown in FIG. 1A, the first protective film 20 and the second protective film 30 are attached to the substrate 10 from above and below, and the protective films 20, The outer peripheral edge 11 of the substrate 10 is covered by 30 and then the substrate 10 is attached to the rotary stage 1 of the spin coater (film attachment). Next, as shown in FIG. 1B, the coating agent 2 is dropped on the substrate 10 while rotating the rotary stage 1 at a high speed, and the coating agent 2 is spread on the substrate 10 (spin coating). Next, as shown in FIG.1 (c), the board | substrate 10 is removed from the rotation stage 1, and the 1st protective film 20 and the 2nd protective film 30 are peeled and removed from the board | substrate 10 (film removal).

Thus, the substrate 10 on which the coating film 40 having a uniform thickness is formed, and the coating agent 2 adheres to the outer peripheral edge portion 11 of the substrate 10 covered with the first protective film 20 and the second protective film 30. Not done.
FIG. 2 is a process diagram showing a coating film forming method according to one embodiment of the present invention. As shown in FIG. 2, the coating film formation method which concerns on 1 aspect of this invention is a board | substrate preparation process (step S1), a 1st protective film sticking process (step S2), a 2nd protective film sticking process (step S3), A film bonding process (step S4), an application process (step S5), and a film removal process (step S6) are included.

(Board preparation process)
FIG. 3 is a plan view for explaining the coating film forming method according to the first embodiment. FIG. 4 is a cross-sectional view for explaining the coating film forming method according to the first embodiment, and is a cross-sectional view along the line AA shown in FIGS.
In the substrate preparation step, as shown in FIGS. 3A and 4A, a substrate 10 on which a coating film is to be formed is prepared. In the present embodiment, the shape of the substrate 10 is a square, but the shape of the substrate is not limited to a square and is arbitrary. The material, size, thickness, etc. of the substrate 10 are also arbitrary. Examples of the material of the substrate 10 include glass, metal, resin, and ceramic.

(First protective film application process)
In the first protective film attaching step, as shown in FIGS. 3B and 4B, the first protective film 20 is attached to the upper surface 12 of the substrate 10 prepared in the substrate preparing step. The first protective film 20 has a rectangular frame shape having an opening 21. The outer contour of the first protective film 20 is larger than the outer contour of the substrate 10, and the first protective film 20 is attached to the substrate 10 such that the outer peripheral edge 22 protrudes from the outer peripheral edge of the substrate 10. The opening 21 of the first protective film 20 is smaller than the outer contour of the substrate 10 and is provided in a region corresponding to the region 12a where the coating film 40 is formed. In a state where the first protective film 20 is attached to the substrate 10, the opening 21 coincides with the region 12 a where the coating film 40 is formed.

  In addition, although the shape of the outer contour of the first protective film 20 is not limited to a square and is arbitrary, the outer contour of the first protective film 20 is preferably larger than the outer contour of the substrate 10. In addition, the shape of the opening 21 of the first protective film 20 is not limited to a square but is arbitrary, but when the first protective film 20 is attached to the substrate 10, the entire region 12 a where the coating film 40 is formed. Is preferably included in the opening 21.

More preferably, the region 21a where the opening 21 and the coating film 40 are formed has the same shape, and the region where the opening 21 and the coating film 40 are formed when the first protective film 20 is attached to the substrate 10. It is preferable that 12a matches. Then, the shape and size of the coating film 40 can be arbitrarily selected by adjusting the shape and size of the opening 21.
The 1st protective film 20 is a film with the adhesion layer comprised by the film and the adhesion layer formed in the main surface at the side of the board | substrate 10 of the said film, for example. In addition, the 1st protective film 20 is not limited to the film with the adhesion layer affixed on the board | substrate 10 with the adhesive force of an adhesion layer, The film affixed on the board | substrate 10 by thermocompression bonding etc. by the heat seal method etc. may be sufficient. .

Examples of the film constituting the first protective film 20 include resin films made of PET, PEN, PC, PI, and the like, and a polymer film having resistance to the coating agent 2 is preferable.
The pressure-sensitive adhesive layer constituting the first protective film 20 is such that the first protective film 20 is not peeled off from the substrate 10 during spin coating, and can be peeled off from the substrate 10 after spin coating. What has power is preferable. Further, the adhesive layer constituting the first protective film 20 is preferably such that no adhesive remains on the substrate 10 after the first protective film 20 is peeled from the substrate 10. Furthermore, the first protective film 20 is preferably attached to the substrate 10 without any gap so that the coating agent 2 does not enter between the first protective film 20 and the substrate 10 during spin coating. For that purpose, it is preferable that the adhesion layer which comprises the 1st protective film 20 is formed in the whole main surface at the side of the board | substrate 10 of the film which comprises the 1st protective film 20. FIG.

  In a state where the first protective film 20 is attached to the substrate 10, the width W1 of the region 12b covered with the first protective film 20 on the upper surface 12 of the substrate 10 is preferably 3 mm or more. When the width W1 is less than 3 mm, it is difficult to attach the first protective film 20 to the substrate 10, and the first protective film 20 may be peeled off from the substrate 10 by centrifugal force due to high-speed rotation during spin coating.

  FIG. 5 is a diagram showing the results of measuring the thickness of the outer peripheral edge of the coating film. In FIG. 5, the solid line indicates the case where the coating film 40 is formed using the thick first protective film 20 (the film with the adhesive layer having a thickness of 25 μm and the adhesive layer having the thickness of 25 μm formed on the film having a thickness of 50 μm). The surface height of the outer peripheral edge portion of the coating film is shown, and the broken line uses a thin first protective film 20 (a film with a 26 μm thick adhesive layer in which a 1 μm thick adhesive layer is formed on a 25 μm thick film). The surface height of the outer peripheral edge portion of the coating film when the coating film 40 is formed is shown.

When the thickness of the 1st protective film 20 is thicker than the thickness of the coating film 40, the 1st protective film 20 will be a thick film or a thin film, but the outer periphery 41 (FIG. 3 (f) ))), Thick portions 41a and 41b as shown in FIG. 5 are generated. Therefore, the thickness of the first protective film 20 is preferably equal to the thickness of the coating film 40.
Thick portions 41a and 41b are formed in the outer peripheral edge 41 of the coating film 40 at the inner peripheral edge 23 (see FIG. 3B) of the first protective film 20 during spin coating. This is because the agent 2 is blocked and a liquid pool is generated near the outer periphery of the opening 21. The phenomenon in which such thick portions 41a and 41b are generated is significant when the first protective film 20 is a thick film as shown in FIG. Accordingly, the first protective film 20 is preferably a thin film.

(Second protective film application process)
In the second protective film attaching step, as shown in FIGS. 3C and 4C, the second protective film 30 is attached to the lower surface 13 of the substrate 10 after the first protective film 20 is attached. In the present embodiment, the first protective film 20 is attached to the substrate 10 first, but the second protective film 30 may be attached to the substrate 10 before the first protective film 20. That is, in the coating film forming method according to an aspect of the present invention, either the first protective film sticking step or the second protective film sticking step may be performed first.

  The second protective film 30 has a rectangular frame shape having an opening 31. The outer contour of the second protective film 30 is larger than the outer contour of the substrate 10, and the second protective film 30 is affixed to the substrate 10 such that the outer peripheral edge 32 protrudes from the outer peripheral edge of the substrate 10. The opening 31 of the second protective film 30 is provided to secure a space for attaching the substrate 10 to the rotary stage 1 of the spin coater by vacuum suction or the like. In order to prevent the coating agent 2 from adhering to the lower surface 13 of the substrate 10, it is preferable that the opening 31 be as small as possible within a range in which the substrate 10 can be attached to the rotary stage 1.

In addition, although the shape of the outer contour of the second protective film 30 is not limited to a square and is arbitrary, the outer contour of the second protective film 30 is preferably larger than the outer contour of the substrate 10. Moreover, the opening 21 of the 1st protective film 20 is not limited to a square shape, but is arbitrary.
The 2nd protective film 30 is a film with the adhesion layer comprised by the film and the adhesion layer formed in the main surface at the side of the board | substrate 10 of the said film similarly to the 1st protection film 20, for example. In addition, the 2nd protective film 30 is not limited to the film with the adhesion layer affixed on the board | substrate 10 with the adhesive force of an adhesion layer, The film affixed on the board | substrate 10 by thermocompression bonding etc. by the heat seal method etc. may be sufficient. .

Examples of the film constituting the second protective film 30 include resin films made of PET, PEN, PC, PI, and the like, and a polymer film having resistance to the coating agent 2 is preferable.
The pressure-sensitive adhesive layer constituting the second protective film 30 is such that the second protective film 30 is not peeled off from the substrate 10 at the time of spin coating and that the second protective film 30 can be peeled off from the substrate 10 after spin coating. What has power is preferable. The adhesive layer constituting the second protective film 30 is preferably such that no adhesive remains on the substrate 10 after the second protective film 30 is peeled off from the substrate 10. In a state where the second protective film 30 is attached to the substrate 10, the width W2 of the region where the lower surface 13 of the substrate 10 is covered by the second protective film 30 is preferably 3 mm or more. When the width W2 is less than 3 mm, it is difficult to attach the second protective film 30 to the substrate 10, and the second protective film 30 may be peeled off from the substrate 10 by centrifugal force due to high-speed rotation during spin coating.

The second protective film 30 has a thickness that can support the portion of the first protective film 20 that protrudes from the substrate 10 from below, thereby preventing the protruding portion from bending downward due to its own weight. preferable. Therefore, the thickness of the second protective film 30 is preferably equal to or greater than the thickness of the first protective film 20.
(Film bonding process)
In the film bonding step, the outer peripheral edge 22 of the first protective film 20 and the outer peripheral edge 32 of the second protective film 30 are bonded together as shown in FIGS. 3 (d) and 4 (d). Since each of the first protective film 20 and the second protective film 30 has an adhesive layer, the first protective film 20 and the second protective film 30 can be easily bonded together, and a process of applying an adhesive for bonding is not necessary.

  In the outer peripheral edge portion 22 of the first protective film 20 and the outer peripheral edge portion 32 of the second protective film 30, the coating agent 2 enters between the first protective film 20 and the second protective film 30, and the side surface 14 of the substrate 10. In order to reliably prevent the coating agent 2 from adhering to the surface, the coating material 2 is bonded over the entire circumference in the circumferential direction (the portion with the pattern in FIG. 3D is the bonding region 3).

  However, in the coating film forming method according to one embodiment of the present invention, the coating film may not necessarily be bonded over the entire circumference, and the coating agent 2 is bonded in a discontinuous manner to the extent that the coating agent 2 does not adhere to the side surface 14 of the substrate 10. May be. FIGS. 6A and 6B are diagrams for explaining a film bonding process according to Modification Example 1. FIG. 6A is a plan view, and FIG. 6B is along the line AA shown in FIG. FIG. 6C is a cross-sectional view taken along line BB shown in FIG. For example, as shown in FIG. 6, the outer peripheral edge portion 22 of the first protective film 20 and the outer peripheral edge portion 32 of the second protective film 30 may be bonded only on a pair of opposing sides (FIG. 6 ( The areas 4 and 5 where the pattern is included in a) are the areas that are pasted together).

In the coating film forming method according to an aspect of the present invention, the outer peripheral edge portion 22 of the first protective film 20 and the outer peripheral edge portion 32 of the second protective film 30 are bonded to each other from the substrate 10 of the first protective film 20. Even if the protrusion width W3 (see FIGS. 3B and 4B) is not increased, the coating agent 2 can be prevented from adhering to the lower surface and side surfaces of the outer peripheral edge portion 11 of the substrate 10.
(Coating process)
In the coating process, as shown in FIGS. 3 (e) and 4 (e), while rotating the rotary stage 1 at a high speed, the discharge nozzle disposed above the substrate 10 is directed toward the center of the upper surface 12 of the substrate 10. A liquid coating agent 2 is dropped. As a result, the coating agent 2 spreads, and the coating agent 2 is applied to the region 12 a where the coating film 40 is formed on the upper surface 12 of the substrate 10 and the entire upper surface of the first protective film 20. However, the coating agent 2 is not applied to the region 12 b covered with the first protective film 20 on the upper surface 12 of the substrate 10.

  At the time of spin coating, the coating agent 2 dripped onto the upper surface 12 of the substrate 10 protrudes from the upper surface 12 of the substrate 10 and scatters due to the centrifugal force generated by the high-speed rotation of the substrate 10. However, since the 1st protective film 20 and the 2nd protective film 30 are affixed on the board | substrate 10, the upper surface of the outer periphery 11 of the board | substrate 10 covered with these 1st protective films 20 and the 2nd protective film 30 The coating agent 2 does not adhere to the lower and side surfaces.

  In the present embodiment, the adhesive itself (stock solution) is applied as the coating agent 2. In such a case, the viscosity of the coating agent 2 is high. When the viscosity of the coating agent 2 is high, the coating agent 2 easily pulls the yarn and spins around the lower surface 13 and the side surface 14 of the substrate 10 during spin coating, so that the effect of the coating film forming method according to one embodiment of the present invention is exhibited. . In particular, when the viscosity of the coating agent 2 is 50 mPa · s or more, the coating agent 2 is likely to wrap around the lower surface 13 and the side surface 14 of the substrate 10, so that the effect of the coating film forming method according to one embodiment of the present invention is exhibited. . In addition, the coating agent 2 which concerns on this Embodiment should just contain the adhesive, and the adhesive itself or what melt | dissolved and diluted the adhesive in the solvent may be sufficient.

(Film removal process)
In the film removal step, the first protective film 20 and the second protective film 30 are peeled off and removed from the substrate 10 as shown in FIGS. 3 (f) and 4 (f). By removing the first protective film 20 and the second protective film 30, the upper surface and the lower surface of the outer peripheral edge portion 11 of the substrate 10 to which the coating agent 2 is not attached are exposed. Thereby, the board | substrate 10 in which the coating film 40 is not formed in the outer periphery part 11 is obtained.

<Second Embodiment>
FIG. 7 is a plan view for explaining the coating film forming method according to the second embodiment. As shown in FIG. 7, in the coating film forming method according to the second embodiment, the shape of the substrate 110, the first protective film 120, and the second protective film 130 is the same as that of the substrate 10 according to the first embodiment. Except for the differences from the shapes of the first protective film 20 and the second protective film 30, it is basically the same as the coating film forming method according to the first embodiment. Therefore, description of common parts is omitted or simplified, and different points will be mainly described.

(Board preparation process)
In the substrate preparation step, as shown in FIG. 7A, a substrate 110 to be a target for forming a coating film is prepared. In the present embodiment, the shape of the substrate 110 is a substantially circular shape having a cutout portion 115 cut out in a straight line at one place on the outer peripheral edge.
(First protective film application process)
In the first protective film attaching step, as shown in FIG. 7B, the first protective film 120 is attached to the upper surface 112 of the substrate 110 prepared in the substrate preparing step. The first protective film 20 has a substantially annular shape having an opening 121. The outer contour of the first protective film 120 is larger than the outer contour of the substrate 110, and the first protective film 120 is attached to the substrate 110 such that the outer peripheral edge 122 protrudes from the outer peripheral edge of the substrate 10. The opening 121 of the first protective film 120 has the same shape as the outer contour of the substrate 110, but is smaller than the outer contour of the substrate 110. In the state where the first protective film 120 is attached to the substrate 110, the opening 121 coincides with the region 112a where the coating film 140 is formed.

  In addition, although the shape of the outer contour of the first protective film 120 is not limited to a substantially circular shape and is arbitrary, the outer contour of the first protective film 120 is preferably larger than the outer contour of the substrate 110. In addition, the shape of the opening 121 of the first protective film 120 is not limited to a substantially circular shape but is arbitrary, but when the first protective film 120 is attached to the substrate 110, the region 12a where the coating film 140 is formed is formed. It is preferable that the entirety is contained in the opening 121.

  8A and 8B are diagrams for explaining the first protective film according to the modified example 2, in which FIG. 8A is a plan view, and FIG. 8B is an AA line shown in FIG. 8A. FIG. The first protective film 20 according to the first embodiment and the first protective film 120 according to the second embodiment have the same outer contour shape and the shapes of the openings 21 and 121, but the outer contour shape. And the shapes of the openings 21 and 121 may be different. For example, like the 1st protective film 220 which concerns on the modification 2 shown in FIG. 8, although an outer contour is the substantially same circle as 2nd Embodiment, the opening 221 is the same square as 1st Embodiment, Also good. Also in this case, the first protective film 220 is affixed to the outer peripheral edge 211 of the substrate 210, and the coating liquid does not adhere to the area 212b covered with the first protective film 220 on the upper surface 212. Further, in a state where the first protective film 220 is attached to the substrate 210, the opening 221 and the region 212a where the coating film is formed coincide with each other.

  FIG. 9 is a view for explaining the first protective film according to the third modification. In the first protective film 20 according to the first embodiment and the first protective film 120 according to the second embodiment, in the state where the first protective films 20, 120 are attached to the substrates 10, 110, the openings 21, 121. However, it is not always necessary to match the regions where the coating films 40 and 140 are formed. That is, the opening 121 of the first protective film 120 does not necessarily define a region where the coating film 140 is formed.

  For example, in Modification 3 shown in FIG. 9, the coating film is formed in a region smaller than the opening 221 of the first protective film 220. Specifically, first, as shown in FIG. 9A, the first protective film 120 and the second protective film 130 are attached to the substrate 110 from above and below, and the outer peripheral edge portion of the substrate 110 is formed by the protective films 120 and 130. 111 is covered, and then the substrate 110 is attached to the rotary stage 1 of the spin coater (film attachment). Next, as shown in FIG. 9B, the auxiliary protective film 360 is pasted from above the first protective film 120. Since the outer contour of the auxiliary protective film 360 is larger than the opening 121 of the first protective film 120, the outer peripheral edge of the auxiliary protective film 360 overlaps with the first protective film 120 as shown in FIG.

The auxiliary protective film 360 is provided with an opening 361 smaller than the opening 121 of the first protective film 120, and the opening 361 coincides with a region where the coating film 340 is formed. Except for the region where the coating film 340 is formed, the first protective film 120 and the auxiliary protective film 360 are covered.
Next, as shown in FIG. 9D, the coating agent 102 is dropped on the substrate 110 while rotating the rotary stage 1 at a high speed to spread the coating agent 102 on the substrate 110 (spin coating). Next, as shown in FIG. 9E, the substrate 110 is removed from the rotary stage 1, and the first protective film 120 and the second protective film 130 are peeled off and removed from the substrate 110 (film removal).

  10A and 10B are diagrams for explaining the first protective film according to the modified example 4, in which FIG. 10A is a plan view, and FIG. 10B is a BB line shown in FIG. FIG. In the first protective film 20 according to the first embodiment and the first protective film 120 according to the second embodiment, the number of openings 21 and 121 is one, but the number of openings is not limited to one. For example, a plurality of openings 421 may be formed as in the first protective film 420 according to Modification 4 shown in FIG. In this case, the first protective film 420 is affixed to the outer peripheral edge 411 of the substrate 410, and the coating liquid does not adhere to the region 412 b covered with the first protective film 420 on the upper surface 412 of the first protective film 420. . And in the state which affixed the 1st protective film 420 on the board | substrate 410, each opening 421 and the area | region 412a which forms a coating film correspond.

(Second protective film application process)
In the second protective film attaching step, as shown in FIG. 7C, the second protective film 130 is attached to the lower surface of the substrate 110 after the first protective film 120 is attached. The second protective film 130 has a substantially annular shape having an opening 131. The outer contour of the second protective film 130 is larger than the outer contour of the substrate 110, and the second protective film 130 is attached to the substrate 110 such that the outer peripheral edge 132 of the second protective film 130 protrudes from the outer peripheral edge of the substrate 110. The opening 131 of the second protective film 130 is provided to secure a space for attaching the substrate 110 to the rotary stage 1 of the spin coater by vacuum suction or the like.

(Film bonding process)
In the film bonding step, as shown in FIG. 7D, the outer peripheral edge 122 of the first protective film 120 and the outer peripheral edge 132 of the second protective film 130 are bonded together. The outer peripheral edge 122 of the first protective film 120 and the outer peripheral edge 132 of the second protective film 130 are such that the coating agent 102 enters between the first protective film 120 and the second protective film 130, and In order to surely prevent the coating agent 102 from adhering, it is bonded over the entire circumference in the circumferential direction (the portion with the pattern in FIG. 7D is the bonding region 103).

(Coating process)
In the coating process, as shown in FIG. 7E, the coating agent 102 is applied to the region 112a where the coating film 140 is formed on the upper surface 112 of the substrate 110 and the entire upper surface of the first protective film 120 by spin coating. Agent 102 is applied. However, the coating agent 102 is not applied to the region 112 b covered with the first protective film 120 on the upper surface 112 of the substrate 110.

  At the time of spin coating, the coating agent 102 dripped onto the upper surface 112 of the substrate 110 protrudes from the upper surface 112 of the substrate 110 or scatters due to the centrifugal force generated by the high-speed rotation of the substrate 110. However, since the first protective film 120 and the second protective film 130 are attached to the substrate 110, the upper surface of the outer peripheral edge 111 of the substrate 110 that is covered with the first protective film 120 and the second protective film 130. The coating agent 102 does not adhere to the lower and side surfaces.

(Film removal process)
In the film removing step, as shown in FIG. 7F, the first protective film 120 and the second protective film 130 are peeled off from the substrate 110 and removed. By removing the first protective film 120 and the second protective film 130, the upper and lower surfaces of the outer peripheral edge 111 of the substrate 10 to which the coating agent 102 is not attached are exposed. Thereby, the substrate 110 in which the coating film 140 is not formed on the outer peripheral edge 111 is obtained.

<Experiment>
As a result of conducting various experiments and examinations on the conditions for bonding the first protective film and the second protective film, the following findings could be obtained.
Generally, in order to form the uniform coating film 40 by spin coating, a rotational speed of about 2500 to 3500 rpm is required. However, if the protruding width W3 of the first protective film and the protruding width W4 of the second protective film 30 (see FIGS. 3C and 4C) are wide, the protruding portion bends downward under its own weight, and the substrate It will flutter when 10 is rotated at a high rotational speed. As a result, the particles in the spin coater environment are wound up, and the particles adhere to the coating film 40. Therefore, an experiment was conducted to examine how much the protrusion width of the film is kept to suppress the fluttering of the protruding portion, and as a result, prevention of particle adhesion.

  FIG. 11 is an enlarged cross-sectional view showing a portion surrounded by a two-dot chain line in FIG. Here, as shown in FIG. 11, the protruding width of the film is the protruding width W5 of the first protective film 20 and the second protective film in a state where the first protective film 20 and the second protective film 30 are bonded together. It means the wider one of the 30 protruding widths W6. In the example shown in FIG. 5, since the width W5 is wider than the width W6, the film protrusion width is the protrusion width W5 of the first protective film 20.

  FIG. 12 is a diagram showing the relationship between the film protrusion width and the number of adhered particles. FIG. 12 shows the result of measuring the number of adhered particles attached to the upper surface of the coating film 40 when a silicon wafer was used as the substrate 10 and the film protrusion width was changed and rotated at 3000 rpm. As the film protrusion width increases, the number of adhering particles adhering to the upper surface of the coating film 40 increases. From this point of view, it is understood that the film protrusion width is preferably narrow. Furthermore, compared with the case where the protective films 20 and 30 are not attached, the number of adhered particles is equal when the film protrusion width is 20 mm, but the number of particle adhesion increases when the film protrusion width is 30 mm or more. .

  Thus, in order to prevent adhesion of particles, it is preferable that the film protrusion width is narrow. However, since the substrate 10 has a thickness, a gap portion 6 (see FIG. 11) exists between the side surface 14 of the substrate 10 and the bonding region 3. Therefore, if the film protrusion width is too narrow, the protective films 20 and 30 cannot be bonded together. In order to securely bond the protective films 20 and 30 to each other, it is necessary to determine the width of protrusion of the film by taking into account the width W7 of the gap 6.

FIG. 13 is a diagram for explaining a peeling experiment by the double cantilever method. As shown in FIG. 13, when a razor 53 is inserted between two bonded films 51 and 52, the films 51 and 52 are peeled off. The peel distance is “a”, the thickness of the film 51 is “h-1”, the thickness of the film 52 is “h-2”, the thickness of the razor 53 is “d”, and the flexural modulus of the film 51 is “E-1”. When the flexural modulus of the film 52 is “E-2”, the dissociation energy Gc when the two films 51 and 52 are peeled can be expressed by the following formula 1. Here, C is Ci = 1 + 0.64 (hi / a).

  Therefore, in Equation 1, the thickness of the first protective film 20, the thickness of the second protective film 30, the thickness of the substrate 10, the bending elastic modulus of the first protective film 20, the bending elastic modulus of the second protective film 30, and the first When the peel strengths of the first protective film 20 and the second protective film 30 are substituted, the peel distance a can be obtained. For example, the thickness of the first protective film 20 is 0.075 mm, the thickness of the second protective film 30 is 0.075 mm, the thickness of the substrate 10 is 0.7 mm, the bending elastic modulus of the first protective film 20 is 2.2 GPa, 2 When the bending elastic modulus of the protective film 30 is 2.2 GPa and the peel strength between the first protective film 20 and the second protective film 30 is 0.05 N / 20 mm, the peel distance is 15.9 mm.

  This peeling distance a corresponds to the width 7 of the gap portion 6 generated when the protective films 20 and 30 are bonded together. That is, in order to stably bond the first protective film 20 and the second protective film 30, the width W8 of the bonding region 3 (see FIG. 11) in anticipation of the width W7 of the gap 6 being 15.9 mm. ) Needs to be designed so that the film protrusion width is sufficient.

  FIG. 14 is a diagram showing the relationship between the bending elastic modulus of the protective film and the peel distance. FIG. 14 shows the results of calculating the peel distance a under various conditions by varying the thicknesses of the substrate 10 and the protective films 20 and 30 and the bending elastic modulus of the protective films 20 and 30. From FIG. 14, it can be seen that the peel distance a tends to increase as the flexural modulus of the protective films 20 and 30 and the thickness of the substrate 10 increase. That is, when the protective films 20 and 30 having a high flexural modulus and the thick substrate 10 are used, the projecting width of the film is designed to be wider than the peeling distance a in order to ensure that the protective films 20 and 30 are bonded to each other. There is a need to.

  From FIG. 12, it can be seen that if the film protrusion width is 20 mm or less, particles are difficult to adhere. In order to suppress the film protruding width to 20 mm or less, even if the width W8 of the bonding region 3 is set to 5 mm, which is the minimum requirement, the width W7 of the gap portion 6 needs to be 15 mm or less. That is, in FIG. 14, the condition must be determined in a range where the peel distance a is less than a line of 15 mm. Specifically, when the thickness d of the substrate 10 is 1.0 mm, the bending elastic modulus of the protective films 20 and 30 is preferably about 1 GPa or less. When the thickness d of the substrate 10 is 0.7 mm, the bending elastic modulus of the protective films 20 and 30 is preferably about 2 GPa or less. When the thickness d of the substrate 10 is 0.5 mm, the elastic modulus of the protective films 20 and 30 is preferably about 3 GPa or less.

As described above, the result shown in FIG. 14 is a measure of how to set the flexibility (bending elastic modulus) of the protective films 20 and 30 with respect to the thickness of the substrate 10. In order to prevent adhesion of particles, it is preferable to select the bending elastic modulus of the protective films 20 and 30 and the thickness d of the substrate 10 so that the separation distance a is 15 mm or less.
Next, the relationship between the thickness of the second protective film and the number of adhered particles was examined. Since the thickness of the 1st protective film 20 is restrict | limited by the thickness of the coating film 40, it cannot be made thick freely. Therefore, when the thickness of the protective films 20 and 30 suppresses the fluttering of the protruding portion and prevents the particles from adhering to the coating film 40, the thickness of the second protective film 30 needs to be increased. .

  For the case of using the thin second protective film 30 and the case of using the thick second protective film 30, the number of adhered particles on the coating film 40 when the coating film 40 is formed by the spin coating method, respectively. The measurement results are shown in FIG. FIG. 15 shows that the number of adhered particles is smaller when the second protective film 30 is thicker. This is probably because the thicker second protective film 30 can suppress the fluttering of the protruding portions of the protective films 20 and 30.

<Others>
As mentioned above, although the coating film formation method which concerns on 1 aspect of this invention has been concretely demonstrated based on 1st and 2nd embodiment and those modifications 1-4, the content of this invention is , But not limited to them. For example, the coating film formation method which combined suitably the partial structure of 1st and 2nd embodiment and those modifications 1-4 may be sufficient.

  The method for forming a coating film according to one embodiment of the present invention is useful in producing a support substrate with an adhesive layer used at the time of producing a flexible organic EL display or the like.

2,102 Coating agent 10,110,210,310,410 Substrate 12,112,212,412 Upper surface 13,113 Lower surface 20,120,220,420 First protective film 21,121,221,421 of first protective film Opening 22, 122 Outer peripheral edge portion of first protective film 30, 130 Second protective film 31, 131 Opening of second protective film 32, 132 Outer peripheral edge portion of second protective film 40, 140, 340 Coating film

Claims (6)

A coating film forming method for forming a coating film by applying a coating agent to a predetermined region on a substrate by a spin coating method,
A first protective film having an opening provided in a region corresponding to the predetermined region and having an outer contour larger than the outer contour of the substrate is formed on the upper surface of the substrate, the predetermined region is included in the opening, and the first A first protective film sticking step for sticking the outer peripheral edge of one protective film so as to protrude from the outer peripheral edge of the substrate;
Adhering a second protective film having an outer contour larger than the outer contour of the substrate to the lower surface of the substrate so that the outer peripheral edge of the second protective film protrudes from the outer peripheral edge of the substrate Process,
A film laminating step for laminating the outer peripheral edge of the first protective film and the outer peripheral edge of the second protective film after the first protective film affixing step and the second protective film affixing step;
After the film laminating step, an application step of applying the coating agent to the predetermined region by a spin coating method;
After the coating process, a film peeling process for peeling the first protective film and the second protective film from the substrate;
A coating film forming method comprising: The opening has the same shape as the predetermined region,
In the first protective film attaching step, the first protective film is attached to the upper surface of the substrate so that the opening and the predetermined region coincide with each other.
The coating film forming method according to claim 1. In the film bonding step, the outer peripheral edge of the first protective film and the outer peripheral edge of the second protective film are bonded over the entire circumference in the circumferential direction.
The coating film formation method of Claim 1 or 2. The coating agent is an adhesive.
The coating film formation method in any one of Claims 1-3. The thickness of the second protective film is thicker than the thickness of the first protective film,
The coating film formation method in any one of Claims 1-4. The coating film forming method according to claim 1, wherein the opening has a square shape.

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