Patent Publication Number: US-2019173013-A1

Title: Method of producing film

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of PCT International Application No. PCT/JP2017/032216 filed on Sep. 7, 2017, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2016-187918 filed on Sep. 27, 2016. The above application is hereby expressly incorporated by reference, in its entirety, into the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of producing a film according to a coating method and particularly relates to a method of producing a film formed of an organic semiconductor material, a crystal material, an alignment material, and the like. 
     2. Description of the Related Art 
     Currently, organic semiconductors have been expected as a semiconductor material used for flexible devices and the like. One of the features of organic semiconductors is that the organic semiconductors can be formed by performing coating at a low temperature, compared to inorganic semiconductors such as silicon. Various methods of producing an organic semiconductor film obtained by using organic semiconductors have been suggested. 
     JP5397921B describes a method of producing an organic semiconductor film according to a coating method using an organic semiconductor material. 
     According to the method of producing an organic semiconductor film in JP5397921B, a wedge-like gap is provided between a contact surface and a surface of a substrate, and liquid droplets of a raw material solution are held in a space between the surface of the substrate and the contact surface at the time of forming a state in which liquid droplets are held. In this state, the raw material solution is supplied so as to come into contact with the contact surface. A drying process is performed in a state in which the liquid droplets are held by the contact surface so that the solvent in the liquid droplets is evaporated. The crystallization of the organic semiconductor material is promoted simultaneously with the evaporation of the solvent, and crystal growth progresses toward the closed side of the contact surface to gradually form an organic semiconductor film. 
     WO2016/031968A describes a method of producing a semiconductor film. WO2016/031968A describes an edge cast method of coating a surface of a gate insulating film formed on a gate electrode. 
     According to the edge cast method, a nozzle and a blade are disposed on the gate insulating film. A coating solution is supplied from the nozzle to an edge portion facing the surface of the gate insulating film on which the blade is disposed. The nozzle and the substrate are held at a temperature at which the solvent is evaporated. The substrate is moved in one direction while the coating solution is continuously supplied such that the amount of the coating solution held by the edge portion becomes constant. The organic semiconductor material is crystallized as the solvent in the coating solution supplied from the nozzle is evaporated. 
     SUMMARY OF THE INVENTION 
     An organic semiconductor film can be formed using any of the method of producing an organic semiconductor film in JP5397921B or the method of producing a semiconductor film in WO2016/031968A. However, in regard to an organic semiconductor film, further reduction in film thickness and uniformity in film thickness or the like have been required currently. 
     An object of the present invention is to solve the problems caused by the techniques of the related art described above and to provide a method of producing a high-quality film having a thin film and high uniformity in film thickness or the like. 
     In order to achieve the above-described object, the present invention provides a method of producing a film, comprising: supplying a raw material solution containing a solvent and a material that forms a film onto a substrate and drying the solvent to form the film on the substrate, in which a coating blade holding the raw material solution on the substrate is used, the coating blade has a facing surface which faces a surface of the substrate and at least one side surface which is provided in the periphery of the facing surface and is in contact with the raw material solution, and the solvent of the raw material solution is dried along a specific direction to form the film. 
     It is preferable that at least three surfaces, which are the facing surface and two side surfaces of the coating blade, are in contact with the raw material solution. 
     Further, it is preferable that the specific direction in which the raw material solution is dried is determined by at least one surface from among the facing surface and at least two side surfaces of the coating blade. 
     Further, it is preferable that the specific direction in which the raw material solution is dried is determined only by one surface from among the facing surface and at least two side surfaces of the coating blade. Further, it is preferable that the specific direction in which the raw material solution is dried is determined only by the facing surface of the coating blade. 
     It is preferable that the coating blade has two side surfaces, and two side surfaces are respectively perpendicular to the surface of the substrate and provided so as to face each other. 
     It is preferable that the facing surface of the coating blade is inclined with respect to the surface of the substrate. It is preferable that a tilt angle of the facing surface of the coating blade with respect to the surface of the substrate is in a range of 1° to 6°. 
     It is preferable that a film growth interface of the raw material solution held on the substrate by the coating blade is curved toward the center of the raw material solution. 
     Further, it is preferable that a position of the coating blade is fixed to the surface of the substrate. 
     The coating blade may include an open part that opens at least a part in the periphery of the raw material solution and the substrate may be moved in a direction toward the open part from the center of the raw material solution. 
     In this case, it is preferable that the substrate is moved while the raw material solution is supplied to a space between the surface of the substrate and the coating blade so that the film is continuously formed. 
     It is preferable that, in a case where a boiling point of the solvent of the raw material solution is set as Tb° C. and a substrate temperature is set as Ts° C., the substrate temperature Ts is held at a temperature satisfying an expression of “Tb−50° C.≤Ts≤Tb”. 
     The film is formed of a material having an aligning property. For example, the material having an aligning property is a material or an organic semiconductor that forms a crystal. 
     According to the present invention, it is possible to obtain a high-quality film having a thin film and high uniformity in film thickness or the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view illustrating a coating blade used for a method of producing a film according to an embodiment of the present invention. 
         FIG. 2  is a schematic view illustrating the coating blade used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 3  is a view obtained by enlarging main parts of one end portion of the coating blade used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 4  is a view obtained by enlarging main parts of the other end portion of the coating blade used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 5  is a schematic plan view illustrating the coating blade used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 6  is a schematic view illustrating a side surface of the coating blade used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 7  is a schematic view illustrating one step in a first example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 8  is a schematic view illustrating one step in the first example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 9  is a schematic cross-sectional view illustrating an example of a thin film transistor to be produced using the method of producing a film according to the embodiment of the present invention. 
         FIG. 10  is a schematic cross-sectional view illustrating a first example of a position where a supply port of a supply pipe in the coating blade used for the method of producing a film according to the embodiment of the present invention is disposed. 
         FIG. 11  is a schematic cross-sectional view illustrating a second example of the position where the supply port of the supply pipe in the coating blade is disposed. 
         FIG. 12  is a schematic cross-sectional view illustrating a third example of the position where the supply port of the supply pipe in the coating blade is disposed. 
         FIG. 13  is a schematic view illustrating an example of disposition of a film to be formed according to the method of producing a film according to the embodiment of the present invention. 
         FIG. 14  is a schematic view illustrating one step in a second example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 15  is a schematic view illustrating one step in the second example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 16  is a schematic view illustrating one step in the second example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 17  is a schematic view illustrating one step in the second example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 18  is a schematic view illustrating a first example of a production device used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 19  is a schematic view for describing a third example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 20  is a plan view for describing the third example of the method of producing a film according to the embodiment of the present invention. 
         FIG. 21  is a schematic view illustrating a second example of the production device used for the method of producing a film according to the embodiment of the present invention. 
         FIG. 22  is a schematic view illustrating a coating blade used in an example. 
         FIG. 23  is a schematic cross-sectional view illustrating the coating blade used in the example. 
         FIG. 24  is a schematic view illustrating a coating blade used in a comparative example. 
         FIG. 25  is a schematic cross-sectional view illustrating the coating blade used in the comparative example. 
         FIG. 26  is a schematic view showing a measuring region of a film thickness and a saturation mobility. 
         FIG. 27  is a schematic view showing the film in Example 1. 
         FIG. 28  is a schematic view showing the film in Comparative Example 1. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, a method of producing a film according to the embodiment of the present invention will be described in detail based on preferred embodiments illustrated in the accompanying drawings. 
     Further, hereinafter, “to” indicating the ranges of numerical values includes numerical values described on both sides. For example, the expression “ε is in a range of a numerical value α to a numerical value β” means that the range of s is a range including the numerical value α and the numerical value β and satisfies an expression “α≤ε≤β” shown using the mathematical symbols. 
     Angles such as “an angle represented by a specific numerical value”, “parallel”, “perpendicular”, and “orthogonal” include error ranges typically accepted in the corresponding technical fields unless otherwise specified. 
       FIG. 1  is a schematic perspective view illustrating a coating blade used for a method of producing a film according to an embodiment of the present invention,  FIG. 2  is a schematic view illustrating the coating blade used for the method of producing a film according to the embodiment of the present invention,  FIG. 3  is a view obtained by enlarging main parts of one end portion of the coating blade used for the method of producing a film according to the embodiment of the present invention, and  FIG. 4  is a view obtained by enlarging main parts of the other end portion of the coating blade used for the method of producing a film according to the embodiment of the present invention. 
     A coating blade  10  illustrated in  FIGS. 1 to 4  is used for forming a film  38  (see  FIG. 8 ). A raw material solution  36  is held by a substrate  30 , that is, a surface  30   a  of the substrate  30 . 
     The coating blade  10  includes, for example, a plane portion  12  formed of a rectangular flat plate and at least two side surfaces  14  provided on the plane portion  12 . 
     The plane portion  12  includes a facing surface  12   a  that faces the surface  30   a  of the substrate  30 . For example, two side surfaces  14  are provided in the periphery of the facing surface  12   a . In  FIGS. 1 to 4 , the longitudinal direction of the plane portion  12  is set as a first direction D 1  and a direction orthogonal to the first direction D is set as a second direction D 2  (see  FIG. 1 ). 
     In the coating blade  10 , the plane portion  12  is disposed so as to be spaced from the surface  30   a  of the substrate  30  in a state of facing the surface  30   a , and the facing surface  12   a  of the plane portion  12  is inclined with respect to the surface  30   a  of the substrate  30 . For example, the facing surface  12   a  is an inclined surface which is monotonically inclined with respect to the surface  30   a  of the substrate  30 . 
     Further, the facing surface  12   a  of the coating blade  10  may not be inclined with respect to the surface  30   a  of the substrate  30 , and the facing surface  12   a  may be in parallel with the surface  30   a  of the substrate  30 . 
     A tilt angle θ of the facing surface  12   a  of the coating blade  10  with respect to the surface  30   a  of the substrate  30  is an angle between the facing surface  12   a  of the coating blade  10  and the surface  30   a  of the substrate  30 . 
     For example, the tilt angle θ is preferably in a range of 1 to 60. The tilt angle θ is more preferably in a range of 3° to 5°. In a case where the tilt angle θ is in a range of 1° to 6°, a proper amount of the raw material solution  36  can be held, and the mobility is high in a case of an organic semiconductor film, and thus the film  38  with an excellent film quality can be obtained. 
     The length of the coating blade  10  is not particularly limited and is appropriately determined according to the length of a film to be formed. The length of the coating blade  10  is a length of the plane portion  12  in the longitudinal direction in  FIG. 1 . 
     The width of the coating blade  10  is not particularly limited and is appropriately determined according to the width of a film to be formed. The width of the coating blade  10  is a length of a direction orthogonal to the longitudinal direction described above, that is, the length of the second direction D 2 . 
     Two side surfaces  14  of the coating blade  10  are respectively perpendicular to the surface  30   a  of the substrate  30  and provided so as to face each other. In the coating blade  10 , end surfaces  14   b  of the side surfaces  14  are disposed to face the surface  30   a  of the substrate  30 . At this time, each end surface  14   b  of the side surface  14  and the surface  30   a  of the substrate  30  are disposed with a gap G 3  therebetween. A size d 3  of this gap G 3  is the same as a size d 2  of a second gap G 2  described below. 
     In the coating blade  10 , a supply pipe  16  is provided on the plane portion  12 . The raw material solution  36  is supplied through the supply pipe  16 , and three surfaces which are the facing surface  12   a  and two side surfaces  14  of the coating blade  10  come into contact with the raw material solution  36 . The surface tension is imparted to the raw material solution  36  due to the facing surface  12   a  and two side surfaces  14 . For example, it is preferable that at least three surfaces which are the facing surface  12   a  and two side surfaces  14  of the coating blade  10  are in contact with the raw material solution  36 . 
     In the coating blade  10 , the raw material solution  36  is held in a region surrounded by the plane portion  12  and the side surfaces  14 , and a liquid reservoir  34  of the raw material solution  36  is formed. The liquid reservoir  34  is a region where the facing surface  12   a  and the side surfaces  14  of the coating blade  10  are in contact with the raw material solution  36 . 
     The facing surface  12   a  of the coating blade  10  is inclined, a first gap G 1  and the second gap G 2  having a difference in size between separation gaps are formed in the liquid reservoir  34  between the facing surface  12   a  of the coating blade  10  and the surface  30   a  of the substrate  30 . A size d 1  of the first gap G 1  is larger than the size d 2  of the second gap G 2 . 
     The first gap G 1  is a gap between the surface  30   a  of the substrate  30  and one end portion of the liquid reservoir  34  in the first direction D 1 . The second gap G 2  is a gap between the surface  30   a  and the substrate  30  and the other end portion of the liquid reservoir  34  in the first direction D 1 . The coating blade  10  is provided with two side surfaces  14  and includes an open part  33  formed such that at least a part in the periphery of the raw material solution  36  is opened. Specifically, in the coating blade  10 , the first gap G 1  side between the facing surface  12   a  and the surface  30   a  of the substrate  30  is opened, and this opened side forms the open part  33 . 
     As illustrated in  FIG. 3 , the size d 1  of the first gap G 1  indicates a length between a site  12   c  and the surface  30   a  of the substrate  30 , which means from the site  12   c  at which a liquid surface  36   a  of the raw material solution  36  in the open part  33  of the liquid reservoir  34  is in contact with the facing surface  12   a  of the coating blade  10  to the surface  30   a  of the substrate  30  in a straight line La perpendicular to the surface  30   a  of the substrate  30 . 
     The size d 1  of the first gap G 1  decreases as the raw material solution  36  is dried and finally becomes the same as the size d 2  of the second gap G 2 , in a case where film formation is carried out by fixing the coating blade  10 . Accordingly, the size d 1  of the first gap G 1  is a standard value at the time of supplying the raw material solution  36 . 
     Since the size d 1  of the first gap G 1  at the time of supplying the raw material solution depends on the length of a film to be formed which is in a range of 0.5 mm to 5 mm, the size d 1  is not limited. 
     The size d 2  of the second gap G 2  is the minimum distance between the surface  30   a  of the substrate  30  in the liquid reservoir  34  and the facing surface  12   a  of the coating blade  10  and the value is 40 μm or less. The facing surface  12   a  of the coating blade  10  is monotonically inclined with respect to the surface  30   a  of the substrate  30  as described above. In this case, the length between the surface  30   a  of the substrate  30  and a corner portion  12   d  of the coating blade  10  illustrated in  FIG. 4  becomes the minimum distance. Accordingly, in the coating blade  10  illustrated in  FIG. 2 , the size d 2  of the second gap G 2  is the length between the surface  30   a  of the substrate  30  and the corner portion  12   d  of the coating blade  10 . A range from the above-described site  12   c  to the above-described corner portion  12   d  in the facing surface  12   a  of the coating blade  10  is a range where the coating blade  10  is in contact with the raw material solution  36 , and the range from the above-described site  12   c  to the above-described corner portion  12   d  is referred to as a solution holding portion. 
     The size d 1  of the first gap G 1  is obtained by acquiring a digital image including the substrate  30  from the side surface of the coating blade  10 , inputting this digital image into a computer, drawing the above-described straight line La on the digital image based on this digital image, and measuring the length between the site  12   c  of the facing surface  12   a  and the surface  30   a  of the substrate  30  on the computer. 
     The size d 2  of the second gap G 2  is obtained by acquiring a digital image including the substrate  30  from the side surface of the coating blade  10 , inputting this digital image into a computer, and measuring the length between the surface  30   a  of the substrate  30  and the corner portion  12   d  of the facing surface  12   a  of the coating blade  10  on the computer based on this digital image. 
     As described above, the size d 2  of the second gap G 2  is 40 μm or less. In a case where film formation is carried out by fixing the coating blade  10 , the lower limit of the size d 2  of the second gap G 2  is 0 μm. In other words, film formation may be carried out in a grounded state. In a case where film formation is carried out by moving the coating blade  10  or the substrate  30 , the lower limit of the size d 2  of the second gap G 2  is 10 μm. 
     The size d 2  of the second gap G 2  is 40 μm or less, occurrence of vibration of the raw material solution  36  is suppressed so that the film quality of the film  38  can be improved. As described below, in a case where the film  38  is formed by moving the substrate  30  or the coating blade  10 , occurrence of vibration of the raw material solution  36  in the liquid reservoir  34  can be suppressed, and the moving speed can be increased. Therefore, for example, in a case where a thin film transistor is prepared, a transistor having excellent characteristics can be obtained with high productivity. 
     Meanwhile, the size d 2  of the second gap G 2  exceeds 40 μm, vibration of the raw material solution  36  in the liquid reservoir  34  occurs, and thus the film quality of the film  38  deteriorates. Consequently, for example, in a case where a thin film transistor is prepared, excellent characteristics cannot be obtained. 
     Since the upper limits of the size d 1  of the first gap G 1  and the size d 2  of the second gap G 2  are changed depending on the surface energy (the solvent, the material of the coating blade  10 , and the surface treatment) described below, the present invention is not limited to the above-described upper limits. 
     It is preferable that the size d 3  of the gap G 3  is the same as the size d 2  of the second gap G 2  described above. By setting the size d 3  of the gap G 3  to 40 μm or less, which is the same as the size d 2  of the second gap G 2 , the surface tension can be imparted to the raw material solution  36 , and occurrence of vibration of the raw material solution  36  can be suppressed by the surface tension. Similar to the size d 3  of the gap G 3 , in a case where film formation is carried out by fixing the coating blade  10 , the lower limit of the size d 3  of the gap G 3  is 0 μm. In other words, the film formation may be carried out in a grounded state. In a case where film formation is carried out by moving the coating blade  10  or the substrate  30 , the lower limit of the size d 3  of the gap G 3  is 10 μm. 
     Since the upper limit of the size d 3  of the gap G 3  is changed depending on the surface energy (the solvent, the material of the coating blade  10 , and the surface treatment) described below, the present invention is not limited to the above-described upper limit. 
     The size d 3  of the gap G 3  is obtained by acquiring a digital image including the substrate  30  from the side surface of the coating blade  10 , inputting this digital image into a computer, and measuring the length between the surface  30   a  of the substrate  30  and the bottom surface of the side surface  14  on the computer based on the digital image. 
     The coating blade  10  is disposed on the surface  30   a  of the substrate  30  in a state in which the first gap G 1 , the second gap G 2 , and the gap G 3  described above are maintained, and the liquid reservoir  34  can be allowed to be present in a space between the facing surface  12   a  and the side surfaces  14  of the coating blade  10  and the surface  30   a  of the substrate  30  depending on the amount of the raw material solution  36  to be supplied. 
     The liquid surface  36   a  of the raw material solution  36  is affected by the surface energy of the raw material solution  36 , the surface energy of the facing surface  12   a , and the surface energy of the side surfaces  14 .  FIG. 5  illustrates the liquid surface  36   a  of the raw material solution  36  in the open part  33  of the liquid reservoir  34 . In the raw material solution  36 , it is preferable that a film growth interface Bg is curved toward the center of the raw material solution  36 . 
     The film growth interface Bg indicates a surface where drying of the solvent in the raw material solution  36  progresses during the formation of the film  38  (see  FIG. 8 ). The drying of the solvent in the raw material solution  36  advances along the first direction D 1  described below, and the liquid surface  36   a  is moved to a contact side  13  along the progression of the drying. Therefore, the film growth interface Bg is the liquid surface  36   a.    
     Specifically, as illustrated in  FIG. 5 , it is preferable that the liquid surface  36   a  of the raw material solution  36  in the open part  33  is curved toward the center of the raw material solution  36 . The curvature of the liquid surface  36   a  of the raw material solution  36  is caused by attraction of the raw material solution  36  to two side surfaces  14 . In this case, the liquid surface  36   a  of the raw material solution  36  has a shape of a depression depressed to the contact side  13  in a plan view. In a case where the liquid surface  36   a  of the raw material solution  36  is curved, the vibration of the raw material solution  36  is suppressed so that a film having a small film thickness can be obtained. 
     Further, the liquid surface  36   a  of the raw material solution  36  may protrude toward the center of the raw material solution  36 . In this case, the liquid surface  36   a  has a shape of a projection projected to the open part  33  side in a plan view. The center of the raw material solution  36  indicates the center of gravity of the raw material solution  36 . In a case where the movement of the substrate  30  is accompanied, since the frictional force acts on the raw material solution  36  in a direction opposite to the first direction D 1 , the liquid surface  36   a  is likely to have a shape of a projection in a plan view. 
     By changing the solvent or the like, the surface energy of the raw material solution  36  can be changed. Further, the surface energy of the facing surface  12   a  and the surface energy of the side surfaces  14  can be changed by performing an ultraviolet (UV) treatment, a plasma treatment, and the like. The surface energy can be changed using the material. Since particularly the side surfaces  14  impart the surface tension to the raw material solution  36 , it is preferable that the wettability with respect to the raw material solution  36  and particularly with respect to the solvent is high. In this manner, the liquid surface  36   a  of the raw material solution  36  can be formed in a shape of a depression or a projection. 
     Further, each side surface  14  is set to be perpendicular to the surface  30   a  of the substrate  30 , but the present invention is not limited to the right angle. As illustrated in  FIG. 6 , the side surface  14  may be inclined with respect to the surface  30   a  of the substrate  30 . The inclination of the side surface  14  is accepted to be 45° based on the right angle. In other words, the side surface  14  may be provided at 900±450 with respect to the surface  30   a  of the substrate  30 . It is more efficient that the side surface  14  is perpendicular to the surface  30   a  of the substrate  30  from the viewpoint of the crystal formation area. 
     The size d 3  of the gap G 3  described above and the size d 2  of the second gap G 2  described above are not necessarily the same as each other and may be different from each other. 
     Further, in a case where the substrate  30  is viewed from the upper side of the surface  30   a , the side surfaces  14  are provided by extending in parallel with the first direction D 1  as illustrated in  FIGS. 1 and 5 . In other words, the side surfaces  14  are provided by extending perpendicularly to the second direction. However, the inclination of each side surface  14  in the first direction D 1  is accepted to be 30° based on the state in which the side surface  14  is in parallel with the first direction D 1 . In other words, the side surface  14  may be provided at a disposition angle of 90°+30° with respect to the second direction D 2 . In consideration of the efficiency from the viewpoint of the crystal growth area, it is preferable that two side surfaces  14  are both provided at a disposition angle of 90°. Further, the disposition angles of two side surfaces  14  in a case where the substrate  30  is viewed from the upper side of the surface  30   a  may not be necessarily the same as each other. The disposition angles of two side surfaces  14  may be symmetric or left-right asymmetric. 
     The plane portion  12  and the side surfaces  14  of the coating blade  10  may be integrated or separated. The coating blade  10  is formed of glass, quartz glass, stainless steel, or the like. 
     As the substrate  30 , for example, a glass substrate or a plastic substrate is used. 
     A plastic substrate is formed of, for example, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefins such as polyethylene (PE), polypropylene (PP), polystyrene, ethylene vinyl acetate (EVA), a cycloolefin polymer (COP), and a cycloolefin copolymer (COC); a vinyl-based resin; and polycarbonate (PC), polyamide, polyimide, an acrylic resin, or triacetylcellulose (TAC). The plastic substrate is not bent even at the time of being attempted to be bent and is used for formation according to a roll-to-roll system. 
     Next, a first example of a method of producing a film will be described. 
       FIGS. 7 and 8  are schematic views sequentially illustrating steps in the formation step according to the first example of the method of producing a film of the embodiment of the present invention. 
     The coating blade  10  is disposed on the surface  30   a  of the substrate  30  toward the side surfaces  14 . At this time, the coating blade  10  is provided such that the tilt angle θ, the first gap G 1 , the second gap G 2 , and the gap G 3  are set as described above. In this state, the raw material solution  36  is supplied, through the supply pipe  16 , to a region surrounded by the surface  30   a  of the substrate  30 , the facing surface  12   a , and the side surfaces  14 . 
     At this time, it is preferable that the substrate  30  is held at an appropriate temperature according to the type of the raw material solution  36 . The substrate temperature of the substrate  30  can be adjusted using, for example, a hot plate. Further, it is preferable that the raw material solution  36  is heated to the same temperature as the substrate temperature before being supplied. It is preferable that the supply pipe  16  is also appropriately heated. 
     After the solvent of the raw material solution  36  is evaporated, the film  38  is formed on the surface  30   a  of the substrate  30  as illustrated in  FIG. 8 . In this case, the film  38  is formed by drying the solvent of the raw material solution  36  along a specific direction. The specific direction indicates the first direction D 1  illustrated in  FIGS. 5 and 8 . In this manner, the high-quality film  38  having high uniformity, in which the alignment is aligned, can be obtained. 
     The above-described specific direction indicates a direction in which drying of the solvent in the raw material solution  36  progresses, which is a direction in which the film  38  is formed. Further, the specific direction indicates a direction in which the film growth interface Bg, that is, the liquid surface  36   a  of the raw material solution  36  moves, and this specific direction is also referred to as a coating direction. 
     The above-described specific direction is determined by, for example, the facing surface  12   a  of the plane portion  12  of the coating blade  10 . The facing surface  12   a  of the plane portion  12  is close to the surface  30   a  of the substrate  30  and the corner portion  12   d  (see  FIG. 4 ). At the time of formation of the film  38 , the solvent of the raw material solution  36  is dried from the open part  33  toward the contact side  13  including the corner portion  12   d  (see  FIG. 4 ). In other words, the solvent is dried along the first direction D 1 , and thus the film  38  is formed along the first direction D 1 . 
     The surface tension is imparted to the raw material solution  36  by the side surfaces  14  as described above, but the side surfaces  14  do not affect the determination of the specific direction in the coating blade  10  illustrated in  FIG. 1 . In this case, the specific direction described above is determined only by the facing surface  12   a  of the plane portion  12  of the coating blade  10 . 
     Further, the determination of the specific direction is also affected by the side surfaces  14  in some cases depending on the shape and the size of the coating blade  10 , the surface energy of the raw material solution  36 , and the surface energy of the side surface  14 . 
     By providing the side surfaces  14 , the surface tension can be imparted to the raw material solution  36  as described above. 
     Due to the evaporation of the solvent in the raw material solution  36 , deposition and dissolution of the organic semiconductor, and the like, vibration of the raw material solution  36  occurs. Since the vibration of the raw material solution  36  is suppressed by the surface tension of the side surfaces  14  described above, continuous crystals can be prepared in a stabilized manner. Since the surface tension is imparted, it is preferable that the side surfaces  14  have high wettability with respect to the raw material solution  36  and particularly with respect to the solvent. 
     In a case where the side surfaces  14  are provided, nucleation of the organic semiconductor or the like is suppressed because evaporation of the raw material solution  36  and deposition and dissolution of the organic semiconductor do not occur inside the side surfaces  14 . Accordingly, the uniformity of the film quality in the film  38  can be increased. The uniformity of the film  38  indicates that unevenness in film thickness is small and a continuous crystal film is formed. In addition to this, the uniformity also indicates that the state of the film  38  is uniform, for example, the alignment direction is aligned over the entire film in a case of an alignment film and the crystal orientation is aligned over the entire film in a case of crystal orientation. 
     Due to the capillary phenomenon, since the raw material solution  36  goes around the outside of the side surfaces  14  through a space between the side surfaces  14  and the substrate  30  or the outer periphery of the side surfaces  14 , evaporation of the raw material solution  36  and deposition and dissolution of the organic semiconductor or the like occur outside the side surfaces  14 . 
     However, the side surfaces  14  are present between a site where the raw material solution  36  is evaporated and the liquid reservoir  34  of the raw material solution  36 . Therefore, practically, the vibration is unlikely to be transmitted to the raw material solution  36  inside the side surfaces  14 . As the result, the vibration of the raw material solution  36  is suppressed. 
     The evaporation of the solvent in the raw material solution  36  is suppressed by providing the side surfaces  14 . However, due to the presence of the side surfaces  14 , the evaporation speed of the solvent is practically increased. This is because the raw material solution  36  also goes around the outside of the side surfaces  14  and then is evaporated due to the capillary phenomenon. An increase in evaporation speed leads to a reduction in film thickness of the film  38  of the organic semiconductor film or the like to be formed. As the result, the film  38  with a small film thickness can be obtained so that the thickness of the film  38  can be reduced. Further, the configuration in which two side surfaces  14  are provided has been described, but the configuration is not limited thereto as long as at least one side surface  14  is provided. In a case where at least one side surface  14  is present, the high-quality film  38  having a small film thickness and high uniformity in film thickness or the like can be obtained. 
     Moreover, as a coating method for obtaining a high-quality crystal film, a method of using a coating blade inclined with respect to the surface  30   a  of the substrate  30  (hereinafter, also referred to as a “wedge method”) has been suggested. According to the wedge method, the vibration of the raw material solution is suppressed by the surface tension while the substrate temperature is increased so that discontinuity such as step-cut of crystals is suppressed. The present invention is different from other techniques in terms that the surface tension can be further imparted to the raw material solution  36  by further providing side surfaces on the coating blade. 
     According to a film forming method referred to as an edge cast method, the organic semiconductor is deposited on the outer periphery of a wall, but is different from the film such as an organic semiconductor film or the like described in the present invention. 
     The edge cast method is a coating method of performing crystal growth toward glass which is an edge, but the crystal growth method for an organic semiconductor film described in the present invention is basically not a coating method of performing crystal growth toward the side surface. In the configuration of the side surface  14  illustrated in  FIG. 1 , the crystal growth occurs perpendicular to the side surface  14  and the crystal growth is not performed toward the side surface  14 . 
     Here, in regard to the substrate  30 , in a case where the substrate  30  is present alone or a layer (not illustrated) is formed on the surface  30   a  of the substrate  30  and the film  38  (see  FIG. 8 ) formed of an organic semiconductor material, a crystal material, or an alignment material is formed on the surface of the layer (not illustrated), the surface of the layer corresponds to the surface  30   a  of the substrate  30 . 
     Next, an example of a thin film transistor to be produced according to the method of producing a film will be described. 
       FIG. 9  is a schematic cross-sectional view illustrating an example of a thin film transistor to be produced using the method of producing a film according to the embodiment of the present invention. 
     The thin film transistor  40  illustrated in  FIG. 9  is a bottom-gate top-contact type transistor. The thin film transistor  40  is provided such that a gate electrode  43  is formed on a surface  42   a  of a substrate  42 . An insulating film  44  that covers this gate electrode  43  is formed on the surface  42   a  of the substrate  42 . An organic semiconductor layer  46  is formed on a surface  44   a  of an insulating film  44 . This organic semiconductor layer  46  is produced according to the method of producing a film. A source electrode  48   a  and a drain electrode  48   b  are formed on a surface  46   a  of the organic semiconductor layer  46 . 
     Further, in the thin film transistor  40 , the organic semiconductor layer  46  is formed on the surface  44   a  of the insulating film  44 . In this case, the surface  44   a  of the insulating film  44  corresponds to the surface  30   a  of the substrate  30  as described above. 
     Here, in order to make a low-molecular organic semiconductor obtain high performance such as a high mobility, it is necessary to obtain an aligned continuous crystal film and to maintain the film thickness of the organic semiconductor layer to be small. 
     There is a direction in which electricity easily flows in an organic semiconductor and discontinuity of crystals becomes a resistance due to the aligned continuous crystal film described above. 
     The maintenance of the film thickness of a crystal film to be small is a request in a case of a bottom-gate top-contact type transistor. Since the current path of a thin film transistor is in the vicinity of the interface between the insulating film and the organic semiconductor layer, the thickness of the organic semiconductor layer becomes a resistance component. Typically, it is desired that the thickness of the organic semiconductor layer is several tens of nanometers (several layers). However, as the thickness thereof is decreased, it becomes difficult to carry out film formation through coating. 
     By employing the method of producing a film described above, the organic semiconductor layer  46  which is an aligned continuous crystal film and has a small film thickness can be obtained. Therefore, a thin film transistor having high performance such as a high mobility can be obtained. 
     Further, a transistor on which the organic semiconductor film is formed according to the method of producing a film is not limited to the bottom-gate top-contact thin film transistor  40  illustrated in  FIG. 9 . The transistor may be a bottom-gate bottom-contact type thin film transistor, a top-gate top-contact type thin film transistor, or a top-gate bottom-contact type thin film transistor. 
     In addition to the production of the thin film transistor  40  described above, the method of producing a film can be used for producing various films, for example, a photoelectric conversion film and a photoelectric modulation film such as an organic solar cell, an electrooptic conversion film and an electrooptic modulation film such as an organic EL, a memory such as an organic ferroelectric memory, an organic conductive film, an inorganic conductive film, a polarizing film, an optical retardation film, a light guide, an optical amplification film, a gas sensor such as a volatile organic compound (VOC) sensor, a self-assembled film such as a block copolymer, a molecular alignment film, and a nanoparticle alignment film. 
       FIG. 10  is a schematic cross-sectional view illustrating the first example of a position where a supply port of a supply pipe in the coating blade used for the method of producing a film according to the embodiment of the present invention is disposed.  FIG. 11  is a schematic cross-sectional view illustrating a second example of a position where a supply port of a supply pipe in a coating blade is disposed.  FIG. 12  is a schematic cross-sectional view illustrating a third example of a position where a supply port of a supply pipe in a coating blade is disposed. 
     In the coating blade  10 , a supply port  16   a  of a supply pipe  16  in the plane portion  12  is flush with the facing surface  12   a  of the plane portion  12  illustrated in  FIG. 10 , but the present invention is not limited to this configuration. The supply port  16   a  of the supply pipe  16  may protrude from the facing surface  12   a  of the plane portion  12  as illustrated in  FIG. 11  or the supply port  16   a  of the supply pipe  16  may be depressed from the facing surface  12   a  of the plane portion  12  as illustrated in  FIG. 12  and may be present inside the plane portion  12 . The supply port  16   a  is used to supply the raw material solution  36 . 
     Further, the position where the supply port  16   a  of the supply pipe  16  is disposed is not particularly limited. For example, it is preferable that the supply port  16   a  thereof is disposed in two central sections from among four equal intervals obtained by dividing the length of the first direction D 1  in which the liquid reservoir  34  as a region where the coating blade  10  is in contact with the above-described various raw material solutions  36  is projected on the surface  30   a  of the substrate  30 . Further, the region where the above-described liquid reservoir  34  is projected is a region from the above-described vertical straight line La to the corner portion  12   d  of the plane portion  12  in the coating blade  10  illustrated in  FIGS. 2 to 4 . 
     Next, the second example of the method of producing a film will be described. 
       FIG. 13  is a schematic view illustrating an example of disposition of a film to be formed according to the method of producing a film according to the embodiment of the present invention.  FIGS. 14 to 17  are schematic views sequentially illustrating steps in the second example of the method of producing a film according to the embodiment of the present invention. In  FIGS. 13 to 17 , the same constituent elements as those in the coating blade  10  and the substrate  30  illustrated in  FIGS. 1 to 6  are denoted by the same reference numerals and the detailed description thereof will not be provided. In  FIGS. 14 to 16 , the tilt angle θ, the first gap G 1 , the second gap G 2 , and the gap G 3  are not illustrated, but the tilt angle θ, the first gap G 1 , the second gap G 2 , and the gap G 3  are the same as those in the coating blade  10  illustrated in  FIG. 1 . 
     According to the method of producing a film, the film  38  can be formed in each of a plurality of regions  39  on the surface  30   a  of one substrate  30  illustrated in  FIG. 13 . Each region  39  is a region where the film  38  is formed, and the regions are separated from one another and regularly arranged. For example, the shapes and the areas of the regions  39  are the same. 
     The film  38  to be formed in a plurality of regions  39  corresponds to, for example, the organic semiconductor layer  46  of the thin film transistor  40 . In a case where the thin film transistor  40  is prepared, the plurality of regions  39  are regularly arranged, but the arrangement of the plurality of regions  39  is appropriately determined depending on the target to be prepared and is not particularly limited to the regular arrangement. 
     In a case where a plurality of films  38  are formed on one substrate  30 , a coating head  50  including a plurality of coating blades  11  is used as illustrated in  FIG. 14 . 
     In the coating head  50 , the plurality of coating blades  11  are arranged in a support  52  in the same manner as the arrangement of the regions  39  illustrated in  FIG. 13 . 
     The coating blade  11  is different from the coating blade  10  illustrated in  FIG. 1  in terms of the configuration of the plane portion  12 , but other configurations are the same as the configurations of the coating blade  10  illustrated in  FIG. 1 . In the coating blade  11 , the plane portion  12  does not have a shape of a flat plate and is formed of a block-like member having the facing surface  12   a . The plane portion  12  is attached to the support  52  in accordance with the positions of the regions  39 . In addition, the supply pipe  16  is provided in each coating blade  11 . 
     The coating head  50  includes an elevating unit (not illustrated) which elevates and lowers the coating head  50 ; and a supply unit (not illustrated) which supplies the raw material solution  36  to the coating blade  11 . Further, a heating unit (not illustrated) such as a hot plate which heats the substrate  30  and holds the increased temperature is also provided. 
     Further, the conditions for the substrate temperature and the like during the formation of the film  38  are the same as the conditions in the first example of the method of producing the film  38  illustrated in  FIGS. 7 and 8 . 
     As illustrated in  FIG. 14 , the coating head  50  is disposed such that the facing surfaces  12   a  are directed toward the surface  30   a  of the substrate  30 . 
     Next, the coating blades  11  are provided on the surface  30   a  of the substrate  30  using an elevating unit (not illustrated) by bringing the coating head  50  closer to the surface  30   a  such that the tilt angle θ, the first gap G 1 , the second gap G 2 , and the gap G 3  are set to be the same as described above as illustrated in  FIG. 15 . In this state, the raw material solution  36  is supplied from the supply pipe  16  to a space between the facing surface  12   a  and the surface  30   a  of the substrate  30 . 
     The substrate  30  is heated, and the temperature thereof is maintained to a specific substrate temperature. The solvent in the raw material solution  36  is dried along a specific direction as described above, for example, along the first direction D 1 . In this manner, the film  38  is formed as illustrated in  FIG. 16 . 
     Next, after the raw material solution  36  is dried, the coating head  50  is allowed to be spaced from the surface  30   a  of the substrate  30  using the elevating unit (not illustrated). As illustrated in  FIG. 17 , a plurality of films  38  are formed on the surface  30   a  of the substrate  30 . 
     Next, the third example of the method of producing a film will be described. 
       FIG. 18  is a schematic view illustrating the first example of a production device used for the method of producing a film according to the embodiment of the present invention.  FIG. 19  is a schematic view for describing the third example of the method of producing a film according to the embodiment of the present invention.  FIG. 20  is a plan view for describing the third example of the method of producing a film according to the embodiment of the present invention. 
     A production device  60  illustrated in  FIG. 18  is provided with a stage  64  in an inner portion  62   a  of a casing  62 ; a temperature controller  66  disposed on the stage  64 ; the coating blade  10 ; and a guide rail  74  which moves the coating blade  10  in the first direction D 1  and the direction opposite to the first direction D 1 . The first direction D 1  indicates the longitudinal direction of the plane portion  12  as described above. 
     The stage  64  and the temperature controller  66  are connected to a driver  68 , and movement of the substrate  30  by the stage  64  and control of the temperature of the substrate  30  by the temperature controller  66  are performed by the driver  68 . The coating blade  10  is connected to a supply unit  72  through the supply pipe  16 . 
     The guide rail  74  is connected to a motor  78 , and the motor  78  allows the coating blade  10  to move in the first direction D 1  and the direction opposite to the first direction D 1 . 
     The driver  68 , the supply unit  72 , and the motor  78  are connected to a control unit  79 , and the driver  68 , the supply unit  72 , and the motor  78  are controlled by the control unit  79 . 
     The first direction D 1  is aligned in a direction parallel to the surface of the stage  64 . Accordingly, the direction opposite to the first direction D 1  is also a direction parallel to the surface of the stage  64 . Further, since the substrate  30  is disposed on the stage  64  such that the surface  30   a  of the substrate  30  is in parallel with the surface of the stage  64 , the first direction D is a direction defined as a surface (not illustrated) parallel to the surface  30   a  of the substrate  30 . 
     The stage  64  is a place where the temperature controller  66  is disposed and the substrate  30  is further disposed thereon and is capable of moving the substrate  30  in the first direction D 1  and the direction opposite to the first direction D 1 . Further, the stage  64  is capable of moving the substrate  30  in a second direction D 2  (see  FIG. 1 ) orthogonal to the first direction D 1  and in a direction opposite to the second direction D 2 . 
     The configuration of the stage  64  is not particularly limited as long as the substrate  30  can be moved in the first direction D 1  and the direction opposite thereto, and the second direction D 2  and the direction opposite thereto. The stage  64  may have a configuration of allowing the substrate  30  to move in a third direction D 3  orthogonal to the first direction D 1  and the second direction D 2 . 
     The temperature controller  66  adjusts the temperature of the substrate  30  to a predetermined temperature and holds the temperature. The configuration of the temperature controller  66  is not particularly limited as long as the temperature of the substrate  30  can be set to a predetermined temperature as described above. As the temperature controller  66 , for example, a hot plate can be used. 
     The configuration of the supply pipe  16  connected to the coating blade  10  is not particularly limited as long as various solutions for forming a film described above can be supplied to a space between the facing surface  12   a  (see  FIG. 2 ) of the coating blade  10  and the surface  30   a  of the substrate  30  from the supply unit  72 . It is preferable that the supply pipe  16  has a flexibility so as to follow the coating blade  10  during the movement of the coating blade  10 . The number of the supply pipes  16  is not limited to one, and a plurality of supply pipes  16  may be provided. The number thereof is appropriately determined depending on the size of the coating blade  10 , the size of a film to be formed, and the like. 
     The supply unit  72  is used to supply the raw material solution  36  to a space between the facing surface  12   a  (see  FIG. 2 ) of the coating blade  10  and the surface  30   a  of the substrate  30  as described above and includes a tank (not illustrated) which stores the raw material solution  36 ; a pump (not illustrated) which sends the raw material solution  36  in the tank to the coating blade  10 ; and a flow meter (not illustrated) which measures the amount of the raw material solution  36  to be sent described above. As the supply unit  72 , for example, a syringe pump can be used. 
     It is desired that the supply unit  72  and the supply pipe  16  are heated so that the temperature thereof is adjusted at an appropriate time. The temperature thereof is desirably set to approximately the same temperature as the substrate temperature. The raw material solution  36  can be stably supplied by reliably dissolving the raw material solution  36  for forming a film through the heating. Further, as a difference in temperature between the raw material solution  36  and the substrate  30  at the time of being supplied is decreased, the stabilized liquid reservoir  34  (see  FIG. 2 ) can be formed. 
     Further, the coating blade  10  is provided with a sensor  70  which measures the distance between the surface  30   a  of the substrate  30  to be disposed on the temperature controller  66  and the facing surface  12   a  (see  FIG. 2 ) of the coating blade  10  (see  FIG. 2 ). The sensor  70  is connected to the control unit  79  so that the driver  68 , the supply unit  72 , and the motor  78  are controlled by the control unit  79  based on the distance between the surface  30   a  of the substrate  30  and the facing surface  12   a  (see  FIG. 2 ) of the coating blade  10  (see  FIG. 2 ). The configuration of the sensor  70  is not particularly limited as long as the above-described distance can be measured, and the distance thereof is measured using, for example, an optical measuring method. As the sensor  70 , a sensor using light interference, a sensor using the confocus, or a sensor using laser light can be appropriately used. 
     In the coating blade  10 , a carriage  76  is attached to the guide rail  74 . The carriage  76  can be moved in the first direction D 1  and the direction opposite to the first direction D by the guide rail  74 , and the coating blade  10  is moved in the first direction D 1  and the direction opposite to the first direction D 1  together with the carriage  76 . The carriage  76  is moved in the first direction D 1  and the direction opposite to the first direction D 1  by the motor  78 . 
     The position of the carriage  76  can be calculated based on read values of a linear scale (not illustrated) provided on the guide rail  74 , and thus the position of the coating blade  10  in the first direction D can be calculated. The carriage  76  is capable of changing the height at which the coating blade  10  has been attached and the tilt angle θ. In addition, the moving speed of the facing surface  12   a  (see  FIG. 2 ) of the coating blade  10  is adjusted by the motor  78 . 
     In the production device  60 , the coating blade  10  can be moved in the first direction D 1  and the direction opposite to the first direction D 1 , and the substrate  30  can be moved in the first direction D 1  and the direction opposite to the first direction D 1 . 
     In regard to the size d 1  of the first gap G 1  and the size d 2  of the second gap G 2 , in the production device  60 , the size d 2  of the second gap G 2  is measured based on the amount of the carriage  76  to be elevated in a state in which the facing surface  12   a  of the coating blade  10  is brought into contact with the surface  30   a  of the substrate  30 . The size d 2  of the second gap G 2  can be measured in a case where a micrometer (not illustrated) for adjusting the height is provided in the carriage  76 . Further, the size d 1  of the first gap G 1  can be calculated based on the length of the coating blade  10  in a case where the tilt angle θ of the coating blade  10  is known. In  FIG. 1 , the length of the coating blade  10  is the length of the plane portion  12  in the longitudinal direction. 
     Next, a method of continuously forming a film will be described. 
     The facing surface  12   a  of the coating blade  10  is disposed on the surface  30   a  of the substrate  30  such that the facing surface  12   a  is inclined at a tilt angle θ in a state in which the first gap G 1 , the second gap G 2 , and the gap G 3  described above are provided. 
     Next, the raw material solution  36  is supplied to the liquid reservoir  34  through the supply pipe  16  from the supply unit  72  (see  FIG. 18 ). At this time, the substrate temperature of the substrate  30  is set to a predetermined temperature using the above-described temperature controller  66  (see  FIG. 18 ). 
     The substrate  30  is moved in a direction D B  from the coating blade  10  at a predetermined moving speed in a state in which the facing surface  12   a  of the coating blade  10  is in contact with the raw material solution  36  as illustrated in  FIGS. 19 and 20  while the raw material solution  36  is supplied to a space between the coating blade  10  and the surface  30   a  of the substrate  30 , that is, the liquid reservoir  34 . In this manner, the region where the liquid surface  36   a  of the raw material solution  36  of the open part  33  is in contact with the surface  30   a  of the substrate  30  becomes a crystal growth portion Cg (see  FIG. 19 ) serving as a starting point where the film  38  is formed, and the film  38  is sequentially formed from this crystal growth portion Cg in a direction D F . Therefore, the film  38  is continuously formed in the direction D F  while the raw material solution  36  is applied to the direction D F  in which the coating blade  10  is moved. 
     Even in a case where the film  38  is continuously formed while the raw material solution  36  is supplied, since the surface tension is imparted to the raw material solution  36 , the vibration of the raw material solution  36  is suppressed, and the evaporation speed of the raw material solution  36  is increased by providing the side surfaces  14 , a film having a uniform film thickness can be continuously formed. Therefore, this contributes to raising the speed of film formation. 
     Further, the direction D B  is a direction toward the open part  33  from the center of the raw material solution  36 , which is the same direction as the direction opposite to the first direction D 1  described above. The direction D F  is a direction opposite to the direction D B , which is the same direction as the first direction D 1 . 
     In a case where the film formation is carried out by moving the substrate  30 , the lower limit of the size d 2  of the second gap G 2  is 10 μm as described above, and the lower limit of the size d 3  of the gap G 3  is 10 μm. Since the film formation is carried out while the raw material solution  36  is supplied, the film formation can be made in a state in which the size d 1  of the first gap G 1  is not changed. In addition, the size d 1  of the first gap G 1  may be changed. Even in a case where a film is continuously formed, the size d 2  of the second gap G 2  and the size d 3  of the gap G 3  may be the same as or different from each other. 
     The amount of the raw material solution  36  to be supplied is appropriately determined according to the temperature and the moving speed of the substrate  30 , the size of the film  38  to be formed, and the like. 
     In regard to the crystal growth portion Cg, the crystal growth portion Cg can be specified by acquiring a digital image including the liquid reservoir  34  and the film  38 , inputting this digital image into a computer, and visually observing the vicinity of the boundary between the liquid reservoir  34  and the film  38  based on this digital image. 
     Further, the method of continuously forming the film  38  by moving the substrate  30  in the direction D B  has been described, but the present invention is not limited thereto. In addition, the film  38  can be continuously formed in the direction D F  as described above by moving the coating blade  10  in the direction D F  at a predetermined moving speed. 
     In a case where the boiling point of the solvent in the raw material solution  36  is set as Tb° C. and the substrate temperature is set as Ts° C., it is preferable that the substrate temperature Ts is held to a temperature satisfying an expression “Tb−50° C.≤Ts≤Tb” according to any method of producing the film  38  described above. In a case where the substrate temperature is in the above-described temperature range, evaporation of the solvent in the raw material solution  36  is promoted, and the film formation speed for the film  38  can be increased. Therefore, the productivity of the film  38  can be increased. 
     It is more preferable that the substrate temperature Ts during the formation of the film  38  satisfies an expression “Tb−20° C.≤Ts≤Tb”. Further, the substrate temperature Ts indicates the temperature of the surface  30   a  of the substrate  30 . 
     The moving speed of the substrate  30  during the formation of the film  38 , that is, the moving speed of the facing surface  12   a  of the coating blade  10  is preferably 5 mm/min or greater and more preferably 10 mm/min or greater. In a case where the moving speed described above is 5 mm/min or greater, the film  38  can be formed at a high film formation speed and the productivity can be increased. Further, the upper limit of the moving speed described above is approximately 100 mm/min, and an organic semiconductor film with excellent crystallinity as the film  38  and a high mobility can be obtained in a case where the above-described moving speed is 100 mm/min or less. 
     Further, the film  38  is formed, for example, in an atmosphere under atmospheric pressure. 
     According to the method of producing the film  38 , the distance between the facing surface  12   a  of the coating blade  10  and the surface  30   a  of the substrate  30  is measured by the sensor  70  (see  FIG. 18 ), the first gap G 1 , the second gap G 2 , and the gap G 3  are maintained, and the substrate  30  is moved in the direction D B . 
     The production device  60  is of a single wafer type, but the method of producing a film is not limited to the single wafer type, and a roll-to-roll type production device as a production device  60   a  illustrated in  FIG. 21  may be employed. 
     Further, in the production device  60   a  in  FIG. 21 , the same constituent elements as those in the production device  60  illustrated in  FIG. 18  are denoted by the same reference numerals and the detailed description thereof will not be provided. 
     The production device  60   a  illustrated in  FIG. 21  is different from the production device  60  illustrated in  FIG. 18  in terms that the stage  64  is not provided, the transport form of the substrate  30  is stretched to an unwinding roll  80  and a winding roll  82 , the coating blade  10  is disposed on the surface  30   a  side of the substrate  30  as described above, and the temperature controller  66  is disposed on a rear surface  30   b  side. The configurations other than these are the same as the configurations of the production device  60  illustrated in  FIG. 18 . 
     In the production device  60   a  in  FIG. 21 , the substrate temperature is set to a predetermined temperature by the temperature controller  66  so that the film  38  is formed by the coating blade  10 . Further, during the film formation of the film  38 , the substrate  30  may be transported by being wound up using the winding roll  82 , and the coating blade  10  may be moved. 
     The above-described raw material solution  36  for forming a film is, for example, a solution containing a material having an aligning property. The solution containing a material having an aligning property is, for example, a solution containing a material that forms a crystal or a solution containing an organic semiconductor. The organic semiconductor may be not only a transistor but also an organic solar cell material. Examples of the material having a crystallinity include an organic ferroelectric material such as croconic acid or an imidazole compound; and a gas sensor material such as a pyrrole imine-naphthalene diimide (PI-NDI) compound. 
     Hereinafter, the solution containing an organic semiconductor used for the raw material solution  36  will be described in detail. The solution containing an organic semiconductor typically contains at least an organic semiconductor (organic semiconductor compound) and a solvent. 
     The type of the organic semiconductor is not particularly limited, and a known organic semiconductor can be used. Specific examples thereof include pentacenes such as 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene), tetramethyl pentacene, and perfluoropentacene; anthradithiophenes such as TES-ADT (5,11-bis(triethylsilylethynyl)anthradithiophene), and diF-TES-ADT (2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene); benzothienobenzothiophenes such as DPh-BTBT (2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene) and Cn-BTBT (benzothienobenzothiophene); dinaphthothienothiophenes such as C10-DNBDT (3,11-didecyl-dinaphtho[2,3-d:2′,3′-d′]-benzo[1,2-b:4,5-b′]dithiophene) and Cn-DNTT (dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene); dioxaanthanthrenes such as perixanthenoxanthene; rubrenes; fullerenes such as C60 and PCBM([6,6]-phenyl-C61-butyric acid methyl ester); phthalocyanines such as copper phthalocyanine and fluorinated copper phthalocyanine; polythiophenes such as P3RT (poly(3-alkylthiophene)), PQT (poly[5,5′-bis(3-dodecyl-2-thienyl 1)-2,2′-bithiophene]), and P3HT (poly(3-hexylthiophene)); and polythienothiophenes such as poly[2,5-bis(3-dodecylthiophene-2-yl)thieno[3,2-b]thiophene] (PBTTT). 
     Further, the type of the solvent is not particularly limited, and examples thereof include alcohol-based solvents such as methanol and ethanol; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; aromatic solvents such as benzene and thiophene, and halogen (chlorine, bromine, or the like) substituted substances (halogenated aromatic solvents) thereof; ether-based solvents such as tetrahydrofuran and diethyl ether; amide-based solvents such as dimethylformamide and dimethylacetamide; and sulfonic acid-based solvents such as dimethyl sulfoxide and sulfolane. 
     The present invention is basically configured as described above. Hereinbefore, the method of producing a film according to the embodiment of the present invention has been described in detail, but the present invention is not limited to the above-described embodiments, and various improvements and modifications can also be made within the range not departing from the scope of the present invention. 
     EXAMPLES 
     The features of the present invention will be described in more detail with reference to the following examples. The materials, the reagents, the use amounts, the amounts of materials, the proportions, the treatment contents, the treatment procedures, and the like described in the following examples can be appropriately changed within the range not departing from the scope of the present invention. Accordingly, the range of the present invention should not be limitatively interpreted by the specific examples described below. 
     In the present examples, organic semiconductor layers respectively formed of an organic semiconductor film were formed according to the method of producing a film, thereby obtaining thin film transistors of Examples 1 to 20 and Comparative Example 1. With respect to the thin film transistors in Example 1, Example 2, and Comparative Example 1, the film thicknesses and the thin film transistor element characteristics were evaluated. With respect to the thin film transistors in Examples 3 to 20, the thin film transistor element characteristics were evaluated. 
     Each thin film transistor was prepared in the following manner by setting the channel width to 1 mm and the channel length to 50 μm using the bottom-gate top-contact type thin film transistor  40  illustrated in  FIG. 9 . 
     &lt;Substrate and Lower Electrode&gt; 
     First, after a glass substrate was washed, a gate pattern was prepared through vacuum deposition using a metal mask. Chromium (Cr) having a thickness of 10 nm was deposited as an adhesive layer to form a gate electrode having a thickness of 40 nm using silver (Ag). 
     Next, a polyimide insulating film having a thickness of 0.5 μm was formed by spin-coating the glass substrate and curing the resultant. 
     &lt;Coating of Organic Semiconductor&gt; 
     Next, the glass substrate was provided on a hot plate present on a stage, the temperature of the surface of the substrate was set to 100° C., 120° C., or 140° C., and the surface thereof was coated with the raw material solution described below to form an organic semiconductor film, thereby obtaining an organic semiconductor layer. 
     Slide glass was used as the coating blade. The height of the slide glass with respect to the surface of the glass substrate was adjusted such that the tilt angle was set to be in a range of 1° to 60. 
     Slide glass having a width of 18 mm, 24 mm, or 32 mm was used. 
     The raw material solution whose concentration was adjusted to be in a range of 0.05% to 0.3% by mass was supplied to a space below the coating blade such that the length was set to be in a range of 10 to 20 mm. After the raw material solution was supplied, a glass material having a rectangular parallelepiped shape was provided as the side surface. A glass material having a size of 20 mm×5 mm×2 mm was used as the glass material. 
     The amount of the raw material solution was reduced due to evaporation toward the coating blade and a contact side  92   a  (see  FIG. 23 ) of the substrate in a state in which the coating blade was allowed to stand on the glass substrate and the position thereof was fixed so that an organic semiconductor film was formed. 
     In the raw material solution, anisole was used as the solvent using C4-TBBT (thieno[3,2-f:4,5-f′]bis[1]benzothiophene) as the organic semiconductor. The raw material solution was obtained by heating and dissolving anisole such that the concentration of the above-described organic semiconductor was set to 0.1% by mass. 
     &lt;Formation of Electrode&gt; 
     Next, a gold (Au) film having a thickness of 70 nm was formed on the organic semiconductor layer as a source drain electrode according to a vacuum deposition method performed using a metal mask. The position of the electrode was adjusted such that a thin film transistor was prepared in the vicinity of the center of the organic semiconductor with respect to the coating width thereof. 
     Example 1, Example 2, and Comparative Example 1 
     The coating blade was provided at a tilt angle of 4° using slide glass having a width of 18 mm. The substrate temperature was set to 120° C. The solution concentration of the raw material solution was examined while being adjusted such that a high-quality film having a concentration of 0.05% to 0.3% by mass was able to be obtained. The raw material solution was introduced up to the extent that the solution length was 12 mm. The value of the solution length is a value of the y axis in  FIG. 26 . 
     The numerical value of the solution length was set to a value of the length in a Y direction parallel to the first direction D 1 . The width was set to a value of the length in an X direction orthogonal to the Y direction. 
     Example 1 has a configuration illustrated in  FIGS. 22 and 23 , and a coating blade  90  was configured to include a plane portion  92  and side surfaces  94 . A reference numeral  92   a  in  FIG. 23  represents a contact side. Further,  FIG. 23  is a cross-sectional view taken along a line B 1 —B 2  of  FIG. 22 . 
     In Example 2, an ultraviolet (UV) treatment was performed on the glass material of the side surface of the coating blade. 
     Comparative Example 1 has a configuration illustrated in  FIGS. 24 and 25 , and a coating blade  100  was configured to have only a plane portion  102  and was not provided with a glass material on the side surface thereof. A reference numeral  102   a  in  FIG. 25  represents a contact side. Further,  FIG. 25  is a cross-sectional view taken along a line A 1 -A 2  of  FIG. 24 . 
     Examples 3 to 20 
     The coating blade was provided at a tilt angle of 1° to 6° using slide glass having a width of 18 mm. The substrate temperature was set to 100° C., 120° C., or 140° C. The solution concentration of the raw material solution was examined while being adjusted such that a high-quality film having a concentration of 0.05% to 0.3% by mass was able to be obtained. The raw material solution was introduced up to the extent that the solution length was 12 mm. The value of the solution length is a value of the y axis in  FIG. 26 . 
     In order to evaluate the thin film transistor element characteristics, the saturation mobility of each of nine regions S 1  to S 9  illustrated in  FIG. 26  was measured in the same manner as in Example 1, Example 2, and Comparative Example 1, the measured values were averaged, and the thin film transistor element characteristics were evaluated based on the average value, as described below. 
     The film thicknesses and the thin film transistor element characteristics of Example 1, Example 2, and Comparative Example 1 are listed in Table 1 below. The thin film transistor element characteristics of Examples 3 to 20 are listed in Table 2 below. 
     Further, in Tables 1 and 2 below, the thin film transistor element characteristics are noted as “TFT characteristics”. 
     Hereinafter, the methods of measuring the film thickness of the organic semiconductor film and the saturation mobility of the organic semiconductor film will be described. 
     &lt;Film Thickness&gt; 
     The film thickness of the formed organic semiconductor film was obtained by dividing the region S illustrated in  FIG. 26  into a total of nine regions S 1  to S 9 , and measuring the film thickness of each of the regions S 1  to S 9 . A stylus type step profiler (DEKTAK) was used for measuring the film thickness of the organic semiconductor film. In the coating blade used in the example illustrated in  FIG. 22  and the coating blade used in the comparative example illustrated in  FIG. 24 , the region S was set to have the same range. The range of the region S illustrated in  FIGS. 22 and 24  was set to have a size of 12 mm in the y direction and a size of 18 mm in the x direction. 
     &lt;Saturation Mobility&gt; 
     In regard to the thin film transistor element characteristics, the saturation mobility of each of the prepared thin film transistors was measured using a semiconductor parameter analyzer (manufactured by Agilent Technologies, Inc., 4156C) 
     The saturation mobility was obtained by dividing the region S illustrated in  FIG. 26  into a total of nine regions S 1  to S 9  similar to the measurement of the film thickness and measuring the saturation mobility of each of the regions S 1  to S 9 . 
     The thin film transistor element characteristics were evaluated based on the measured saturation mobilities and the following evaluation standard. 
     A: The saturation mobility p was 1.0 cm 2 /Vs or greater. 
     B: The saturation mobility pt was 0.1 cm 2 /Vs or greater and less than 1.0 cm 2 /Vs. 
     C: The saturation mobility g was 0.01 cm 2 /Vs or greater and less than 0.1 cm 2 /Vs. 
     D: The saturation mobility t was less than 0.01 cm 2 /Vs. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Example 1 
                 Example 2 
                   
               
               
                   
                 Side surfaces: 
                 Side surfaces UV-treated 
                 Comparative Example 1 
               
               
                   
                 glass material 
                 glass material 
                 No side surfaces 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Film 
                   
                 Film 
                   
                 Film 
                   
               
               
                   
                 thickness 
                 TFT 
                 thickness 
                 TFT 
                 thickness 
                 TFT 
               
               
                   
                 (nm) 
                 characteristics 
                 (nm) 
                 characteristics 
                 (nm) 
                 characteristics 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 S 1   
                 29 
                 A 
                 26 
                 A 
                 85 
                 D 
               
               
                 S 2   
                 38 
                 A 
                 35 
                 A 
                 150 
                 D 
               
               
                 S 3   
                 35 
                 A 
                 29 
                 A 
                 95 
                 D 
               
               
                 S 4   
                 27 
                 A 
                 23 
                 A 
                 95 
                 D 
               
               
                 S 5   
                 45 
                 B 
                 35 
                 A 
                 100 
                 C 
               
               
                 S 6   
                 33 
                 A 
                 30 
                 A 
                 110 
                 D 
               
               
                 S 7   
                 30 
                 A 
                 29 
                 A 
                 150 
                 C 
               
               
                 S 8   
                 38 
                 A 
                 33 
                 A 
                 75 
                 B 
               
               
                 S 9   
                 34 
                 A 
                 32 
                 A 
                 120 
                 C 
               
               
                 Average 
                 34 
                 A 
                 30 
                 A 
                 109 
                 D 
               
               
                 Deviation 
                 6 
                 — 
                 4 
                 — 
                 27 
                 — 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Substrate 
                 Tilt 
                 TFT 
               
               
                   
                 temperature (° C.) 
                 angle (°) 
                 characteristics 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Example 3 
                 100 
                 1 
                 C 
               
               
                 Example 4 
                 100 
                 2 
                 C 
               
               
                 Example 5 
                 100 
                 3 
                 B 
               
               
                 Example 6 
                 100 
                 4 
                 B 
               
               
                 Example 7 
                 100 
                 5 
                 B 
               
               
                 Example 8 
                 100 
                 6 
                 C 
               
               
                 Example 9 
                 120 
                 1 
                 B 
               
               
                 Example 10 
                 120 
                 2 
                 B 
               
               
                 Example 11 
                 120 
                 3 
                 A 
               
               
                 Example 12 
                 120 
                 4 
                 A 
               
               
                 Example 13 
                 120 
                 5 
                 A 
               
               
                 Example 14 
                 120 
                 6 
                 B 
               
               
                 Example 15 
                 140 
                 1 
                 C 
               
               
                 Example 16 
                 140 
                 2 
                 B 
               
               
                 Example 17 
                 140 
                 3 
                 A 
               
               
                 Example 18 
                 140 
                 4 
                 A 
               
               
                 Example 19 
                 140 
                 5 
                 A 
               
               
                 Example 20 
                 140 
                 6 
                 B 
               
               
                   
               
            
           
         
       
     
     As listed in Table 1, in Example 1 and Example 2, the film thickness was thin and unevenness in film thickness was small so that a uniform film was obtained, compared to Comparative Example 1. In regard to the TFT characteristics, unevenness in saturation mobility was small and the saturation mobility was uniform. Therefore, the TFT characteristics were excellent. As described above, Example 1 and Example 2, the film thickness was uniform and the uniformity was high so that a high-quality film with excellent TFT characteristics was able to be obtained. In Example 2, the UV treatment was performed on the side surfaces, and thus the wettability of the side surfaces with respect to the raw material solution was higher than that of the side surfaces of Example 1. Therefore, both of the uniformity in film thickness and the uniformity in TFT characteristics were excellent. 
       FIG. 27  illustrates the film of Example 1, and  FIG. 28  illustrates the film of Comparative Example 1.  FIGS. 27 and 28  are both photomicrographs obtained by a polarizing microscope. 
     The uniform film  38  was obtained in Example 1 as illustrated in  FIG. 27 , but the film  38  which had partially turbid regions  104  and was nonuniform as illustrated in  FIG. 28  was formed in Comparative Example 1. The turbid regions  104  were regions where the film thickness was not uniform, the crystal was discontinuous, and the alignment was not made. It was considered that the turbid regions  104  were generated due to extra nucleation caused by repetitive evaporation and dissolution of the raw material solution because side surfaces were not provided. 
     As listed in Table 2, in Examples 3 to 20, the substrate temperatures were 100° C., 120° C., and 140° C., and in a case where the tilt angle was in a range of 3° to 5° regardless of the substrate temperature, the saturation mobility was further increased and excellent TFT characteristics were obtained. 
     Further, the results obtained in a case where slide glass having a width of 24 mm or a width of 32 mm was used for the coating blade were not described, but the results were the same as those obtained in a case where the width of the slide glass was 18 mm. 
     The length of the solution supplied initially was in a range of 10 to 20 mm, which means that the same tendency was obtained. 
     EXPLANATION OF REFERENCES 
     
         
         
           
               10 ,  11 : coating blade 
               12 : plane portion 
               12   a : facing surface 
               12   c : site 
               12   d : corner portion 
               13 ,  92   a ,  102   a : contact side 
               14 ,  94 : side surface 
               14   b : end surface 
               16 : supply pipe 
               16   a : supply port 
               30 : substrate 
               30   a : surface 
               30   b : rear surface 
               33 : open part 
               34 : liquid reservoir 
               36 : raw material solution 
               36   a : liquid surface 
               38 : film 
               39 : region 
               40 : thin film transistor 
               42 : substrate 
               42   a ,  44   a ,  46   a : surface 
               43 : gate electrode 
               44 : insulating film 
               46 : organic semiconductor layer 
               48   a : source electrode 
               48   b : drain electrode 
               50 : coating head 
               52 : support 
               60 ,  60   a : production device 
               62 : casing 
               62   a : inner portion 
               64 : stage 
               66 : temperature controller 
               68 : driver 
               70 : sensor 
               72 : supply unit 
               74 : guide rail 
               76 : carriage 
               78 : motor 
               79 : control unit 
               80 : unwinding roll 
               82 : winding roll 
               90 ,  100 : coating blade 
               92 ,  102 : plane portion 
               104 : region 
             Bg: film growth interface 
             Cg: crystal growth portion 
             D 1 : first direction 
             D 2 : second direction 
             D 3 : third direction 
             D B : direction 
             D F : direction 
             G 1 : first gap 
             G 2 : second gap 
             G 3 : gap 
             S, S 1 , S 2 , S 3 , S 4 , S 5 , S 6 , S 7 , S 8 , S 9 : region 
             θ: tilt angle