JP6222113B2 - Thin film forming method and thin film forming apparatus - Google Patents

Description

  The present invention relates to a thin film forming method and a thin film forming apparatus, and more particularly to a thin film forming method and a thin film forming apparatus for forming a thin film by drying ink applied to a substrate.

  In recent years, as a method for manufacturing an electronic device, research and development of a so-called printed electronics that is manufactured by a printing method without using a conventional photolithography process or a vacuum process has been actively performed.

  Specific examples include LCD color filters and liquid crystal material printing, OLED light emitting and injection layers, electronic paper TFT backplanes, PCB and FPC electrode formation, solar cell wiring, transparent conductive films and touch panels. Many attempts have been made to print devices.

  Formation of organic thin films such as transparent electrodes, light emitting layers and organic layers of OLEDs, organic semiconductor layers of organic transistors, etc. has been studied from the conventional vacuum method to the printing at atmospheric pressure, especially the lamination by the ink jet method. Yes. By forming a coating film by coating and printing, equipment necessary for the vacuum process is unnecessary, and expensive materials can be saved, so that a significant cost reduction is possible.

  Such a functional thin film coating solution is set to have a low solid content concentration so that the thickness of the dried coating film is about 10 to several 100 nm. Therefore, the ink generally has a very low viscosity close to that of the solvent. In addition, since such a thin film is required to have few impurities, it is generally difficult to adjust the viscosity.

  In addition to coating methods such as die coater coating and capillary coating, as a method of forming a uniform thin film coating using a low viscosity coating liquid as ink, flexographic printing, gravure printing, ink jet printing are also possible. Printing is known.

  Above all, patterning is possible, materials can be applied to necessary locations as much as necessary, and low-viscosity ink can be printed, so the inkjet printing method is suitable for application of functional thin films, and various research and development have been conducted. Yes. For example, a light emitting layer, an injection layer, and a transport layer of OLED illumination and a display, an insulating film of an organic semiconductor, an electrode, and an organic semiconductor layer are included.

  However, in the printing by the ink jet method, the functional thin film ink has a low viscosity, so that the liquid flow on the substrate is caused to be flat like the coffee ring phenomenon or the like until it is dried on the substrate. A thin film may not be obtained.

  For example, in organic semiconductor printing of organic TFTs, there are cases where organic semiconductors are printed across the surface of two types of substrates, electrodes and insulating films, but because the wettability of ink differs between electrodes and insulating films, either There is also a problem that ink flows.

  In addition, when printing on a large area, the substrate surface has not a few in-plane variations such as wettability, so that a uniform coating property on a large area becomes a problem.

  Alternatively, when the size (diameter) of the coating film is as small as 10 to 100 μm, for example, liquid flow occurs during a very short time from when the ink is applied to the substrate until it dries. Flatness is impaired.

  As a method of drying by suppressing the flow of ink in a short time until drying, a method of heating the ink together with the substrate, a method of radiant heating with infrared rays, and a method of adjusting the physical properties of the ink can be considered, but each has a problem. .

  In the method of heating ink together with the base material, when a base material such as a film is used, not only the base material is deformed but the mechanical accuracy of the printing apparatus is lowered, but the ink is continuously heated until drying. By doing so, the ink flow is rather increased.

  In the method of radiant heating with infrared rays, the drying speed is slow, and ink liquid flow occurs before the heating effect is obtained.

  In the method of heating the ink together with the base material including infrared heating, the base material has a heat capacity, so that it is difficult to obtain a temperature for dramatically increasing the drying speed of the ink, and it is difficult to obtain the effect of suppressing liquid flow.

  In the method of adjusting the physical properties of the ink, for example, the addition of a thickened material, the addition of a surfactant, the addition of an additive for imparting thixotropic properties, and the like can be considered, but these cause a decrease in the function of the coating film.

  Regarding a method for heating a functional thin film, a method of forming an organic semiconductor by a coating method by heating a precursor of the organic semiconductor is disclosed (Patent Document 1).

  On the other hand, a method is disclosed in which a spot where ink is landed is heated in advance with a laser beam to suppress wetting and spreading of the landed ink (Patent Document 2).

JP 2004-247716 A WO2009 / 076023

  However, the process described in Patent Document 1 is a heating method after forming a thin film, and does not control coating film formation in a short time until the ink is dried.

  On the other hand, in the process of Patent Document 2, the base material is preliminarily heated, and in order to obtain an effect, the deformation of the base material cannot be ignored, particularly in the formation of a thin film coating film of 10 to several hundred nm. There was a problem that the flow was rather increased. The reason why the ink flow is increased is not clear, but it is considered that the ink flow at the initial stage of drying tends to increase because the temperature of the ink increases and the viscosity decreases immediately after landing.

  Accordingly, an object of the present invention is to realize homogenization of the obtained thin film and improvement of flatness with good reproducibility without using a method such as adding an additive to the ink. An object of the present invention is to provide a thin film forming method and a thin film forming apparatus capable of performing heat drying and preventing deformation and modification of a substrate.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

1.
In a method for forming a thin film coating film by applying ink on a substrate, after applying the ink on the substrate, before the ink is dried , flash light is applied to the substrate surface for one irradiation time. The range is from microseconds to 2 milliseconds, an intermittent time of 0.5 milliseconds to 100 milliseconds is provided between each irradiation time, and the ink is heated and dried by continuously irradiating 10 times to 30000 times. A thin film forming method.

2.
Thin film forming method according to claim 1, wherein the illuminance on the substrate surface of the flash light is ^{100mW / cm 2 ~400mW / cm 2} .

3.
3. The method for forming a thin film according to either 1 or 2 , wherein the method for applying ink to the substrate surface is an ink jet method.

4).
4. The thin film forming method according to any one of 1 to 3 , wherein the ink contains an organic semiconductor material.

5.
5. The thin film forming method according to any one of 1 to 4 , wherein a layer that absorbs the high illuminance light is provided in the vicinity of the surface of the base material to which the ink is applied.

6).
6. The method of forming a thin film as described in 5 above, wherein the layer that absorbs high illuminance light is an electrode material.

7).
The layer that absorbs the high illuminance light has an absorbance of 0.01 or more and 3 or less in a part or all of the light source spectrum of the flash light, and
The layer that absorbs high illuminance light is in direct contact with the ink applied on the substrate, or is not in contact with the ink at a distance of 2 μm or less from the ink application position. The method for forming a thin film according to 5 or 6 above.

8).
The thin film forming method according to any one of 1 to 7, wherein the viscosity of the ink is in the range of 1 mPa · s to 30 mPa · s.

9.
In an apparatus for forming a thin film coating film by applying ink onto a substrate, the apparatus applies a flash light to the substrate surface before the ink is dried . The irradiation time is in the range of 1 microsecond to 2 milliseconds, an intermittent time of 0.5 milliseconds to 100 milliseconds is provided between each irradiation time, and the ink is heated and dried by continuously irradiating 10 times to 30000 times. A thin film forming apparatus having a mechanism for

Explanatory drawing which shows an example of the thin film formation method concerning this invention Explanatory drawing which shows the 1st aspect which forms the organic-semiconductor thin film of an organic thin-film transistor with the thin-film formation method concerning this invention Explanatory drawing which shows the 2nd aspect which forms the organic-semiconductor thin film of an organic thin-film transistor with the thin-film formation method concerning this invention Explanatory drawing which shows the 3rd aspect which forms the organic-semiconductor thin film of an organic thin-film transistor with the thin-film formation method concerning this invention Explanatory drawing which shows the 4th aspect which forms the organic-semiconductor thin film of an organic thin-film transistor with the thin-film formation method concerning this invention. The principal part schematic side view which shows an example of the thin film forming apparatus which concerns on this invention It is a principal part schematic plan view of the thin film forming apparatus shown in FIG. The figure which shows the result of an Example and a comparative example The figure which shows the result of an Example and a comparative example The figure which shows the result of an Example and a comparative example The figure which shows the result of an Example and a comparative example

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory view showing an example of a thin film forming method according to the present invention.

  In the thin film forming method according to the present invention, first, a base material 1 is prepared as shown in FIG.

  Next, as shown in FIG. 1B, an ink 2 containing a thin film forming component and a solvent is applied to the surface 10 (also referred to as a substrate surface) of the substrate 1.

  The diameter of the ink 2 (wet film) applied to the substrate surface 10 is not particularly limited, but it is preferably in the range of 5 μm or more and 200 μm or less from the viewpoint of more remarkable effects of the present invention.

  Next, as shown in FIG. 1C, before the ink 2 applied to the substrate surface 10 is dried, the substrate surface 10 is irradiated with high illuminance light, and the ink 2 is heated and dried. Here, “drying” specifically refers to removal of the solvent contained in the ink 2, and “before ink 2 is dried” specifically refers to the solvent contained in the ink 2 being the ink concerned. 2 is a period in which the ink 2 contains the solvent and, more narrowly, a period in which the ink 2 is kept in a low-viscosity state.

  In the present invention, the ink 2 applied to the substrate surface 10 is preferably a low-viscosity ink from the viewpoint of more prominently achieving the effects of the present invention. Specifically, the viscosity is 1 mP · s or more. The range is preferably 30 mPa · s or less, and more preferably 1 mP · s or more and 10 mP · s or less. It is preferable to perform irradiation with high illuminance light within a period in which the ink 2 maintains such a viscosity. The viscosity is a value measured using a rotary viscometer, a vibration viscometer, or the like under a viscosity measurement condition suitable for the above-described viscosity range measurement under a shear rate of about 10 to 1000-1 s.

  The ink 2 is heated and dried by irradiation with high illuminance light, and as shown in FIG. 1D, a solid dry thin film 3 made of a thin film forming component (hereinafter sometimes simply referred to as a thin film). become.

  The thickness of the thin film 3 is not particularly limited, but is preferably in the range of 10 nm or more and 1 μm or less from the viewpoint of more prominently achieving the effects of the present invention.

  According to the present invention, as described above, by heating and drying the ink 2 by irradiation with high illuminance light, for example, without using a method such as adding an additive to the ink 2, the resulting thin film 3 is homogenized. In addition, the effect of improving the flatness with good reproducibility can be obtained. In addition, since high illuminance light is used, the ink can be heated and dried in a short time, and the effect of preventing the deformation and modification of the base material 10 can be obtained.

  In the present invention, the method for applying the ink 2 to the substrate surface 10 is not particularly limited, but a printing method or the like is suitable. As a printing method, a generally known method can be used, and an inkjet method, a screen printing method, a relief printing method, an intaglio printing method, an offset printing method, a flexographic printing method, etc. can be preferably exemplified, and an inkjet method in particular. Is preferred.

  As the ink jet method, for example, a known method such as an on-demand type such as a piezo method or a bubble jet (registered trademark) method or a continuous jet type ink jet method such as an electrostatic suction method can be used.

  Further, in the present invention, the application of the ink 2 is not limited to the case of applying the pre-prepared ink 2, and a plurality of ink components are individually applied to the substrate surface 10, and The ink 2 may be applied as a result of mixing the ink 2 and mixing the ink 2. For example, a method of preparing a desired ink 2 by mixing two or more kinds of inks individually applied by an ink jet method or the like on the substrate surface 10 can be mentioned.

  Alternatively, the ink 2 may be applied after the precursor of the ink component is applied to the substrate surface 10 and then the precursor of the ink component becomes an ink component by reaction.

In the thin film forming method according to the present invention, the high illuminance light is preferably light having an illuminance of at least 100 mW / cm ² on the substrate surface 10, and such light is not particularly limited. However, a laser beam, flash light, etc. can be illustrated preferably. In the present invention, the illuminance on the substrate surface 10 refers to the entire emission wavelength, and is the maximum value of the light emission power conversion value or a value measured by an exposure illuminance measuring machine as appropriate.

The laser light preferably used in the present invention is not particularly limited, but a solid laser such as a ruby laser, a YAG laser, or a glass laser; a He—Ne laser, an Ar ion laser, a Kr ion laser, a CO ₂ laser, Gas laser such as CO laser, He-Cd laser, N ₂ laser, excimer laser; semiconductor laser such as InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, GaSb laser; chemical laser, dye laser It is possible to preferably illustrate the above, and it is possible to appropriately perform a scanning exposure according to the purpose by narrowing it into a beam shape. In order to obtain high resolution by exposure with laser light, electromagnetic waves that can narrow the energy application area, particularly ultraviolet light, visible light, and infrared light with a wavelength of 1 nm to 1 mm are preferable. As such a laser light source, ruby laser is used. Solid lasers such as YAG laser and glass laser; He—Ne laser, Ar ion laser, Kr ion laser, CO ₂ laser, CO laser, He—Cd laser, N ₂ laser, excimer laser and other gas lasers; InGaP laser, Examples thereof include semiconductor lasers such as AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, and GaSb laser; chemical laser, dye laser, and the like.

  The flash light preferably used in the present invention is not particularly limited, but a flash light by a xenon lamp, a halogen lamp, a mercury lamp, or the like can be preferably exemplified, and these exposures may be performed on the entire surface, Or you may carry out through a photomask.

  When the high illuminance light is flash light, it is also preferable to continuously irradiate the substrate surface 10 with the flash light a plurality of times. The irradiation conditions are preferably set as appropriate in accordance with the solvent type of the ink 2, the amount of the ink 2 applied to the substrate surface 10, and the like. For example, when performing multiple continuous irradiations, It is preferable that the irradiation time is in the range of 1 microsecond to 2 milliseconds, and an intermittent time (no irradiation time or low output irradiation time) of 0.5 to 100 milliseconds is provided between the irradiation times. Moreover, it is preferable that the frequency | count of irradiation is the range of 10-30000 times.

  By intermittently performing exposure with high illuminance in this way, the ink applied on the substrate repeats from room temperature → higher temperature → higher temperature → higher temperature → lower temperature →. A heating history different from simple heating can effectively suppress ink flow and form a flat thin film.

  In the present invention, it is preferable that the irradiation range is set so that the high illuminance light irradiated to the substrate surface 10 is directly irradiated to the ink 2 on the substrate surface 10. That is, in the present invention, the ink 2 on the substrate surface 10 can be indirectly heated and dried by the substrate 1 heated by the irradiation of the high illuminance light to the substrate surface 10, but more preferably, Direct drying is performed by directly irradiating the ink 2 on the substrate surface 10.

  In the present invention, the solvent that the ink 2 can contain is not particularly limited, but for example, an organic solvent such as hydrocarbon, alcohol, ether, ester, ketone, glycol ether, or water can be used. It can illustrate preferably, These 1 type (s) or 2 or more types can be mixed and used.

  In the present invention, it is preferable that the ink composition (solvent composition) is appropriately adjusted so that the ink 2 satisfies the above-described conditions for the low-viscosity ink.

  On the other hand, the thin film forming component contained in the ink 2 is not particularly limited, but conductive materials such as conductive fine particles and conductive polymers, insulating materials, semiconductor materials, optical filter materials, dielectric materials. And the like, and organic semiconductor materials are particularly preferable. The thin film forming component is preferably contained in the ink 2 in a state of being dispersed or dissolved in the solvent described above.

  In the case where the ink 2 contains an organic semiconductor material, for example, a material that serves as an acceptor that accepts electrons or a material that serves as a donor that serves as an electron donor is contained, and the thin film obtained is subjected to a so-called doping treatment. You may make it give.

  In addition, the specific aspect which forms an organic-semiconductor layer using an organic-semiconductor material is explained in full detail behind.

  As described above, it is not necessary to add an additive to the ink used in the present invention in order to homogenize the thin film 3 or improve the flatness. For example, the dispersibility or solubility of the thin film forming component in the solvent Additives can be added for the purpose of adjusting the viscosity or for the purpose of optimizing the ink jet method.

  In the present invention, the substrate 1 to which the ink 2 is applied is not particularly limited, but is a substrate that hardly absorbs the components constituting the ink 2 from the viewpoint of more prominently achieving the effects of the present invention. It is preferable. Specific examples of the substrate include glass, plastic (polyethylene, polypropylene, acrylic, polyester, polyamide, etc.), metal (copper, nickel, aluminum, iron, etc., or alloy), ceramic, and the like.

  Moreover, the base material 1 of this invention can use preferably the base material surface 10 which consists of a coating layer which does not absorb a liquid.

  In the present invention, the substrate 1 preferably has a layer that absorbs high illuminance light in the vicinity of the application position of the ink 2 on the substrate surface 10. Thereby, the drying speed of the ink 2 can be further increased, and the effects of the present invention can be exhibited more remarkably.

  The layer that absorbs high illuminance light is preferably an organic layer or inorganic layer that can absorb high illuminance light and convert it into heat, and the absorbance is preferably 0.01 or more and 3 or less in part or all of the light source spectrum. For example, a metal layer deposited or printed, an insulating layer such as polyimide, a colored polymer layer, and the like can be preferably exemplified.

  The ink 2 may be applied so as to be in direct contact with the layer that absorbs high-intensity light, but within a distance that can receive heat energy from the layer that absorbs high-intensity light even if it is non-contact. If it is given, indirect heat drying is promoted, which is preferable. In this case, the distance from the ink 2 application position to the layer that absorbs high illuminance light is preferably 2 μm or less.

  In the base material 1, the layer that absorbs high illuminance light may be provided as a part or all of the base material surface 10, or is not directly exposed to the base material surface 10 and provided as an inner layer of the base material 1. May be.

  In the present invention, an electrode material can be preferably exemplified as an example of a layer that absorbs high illuminance light, and this will be described in detail in the following embodiment of forming an organic semiconductor thin film.

  Below, based on the aspect which forms an organic-semiconductor thin film (organic-semiconductor layer), the thin film formation method concerning this invention is demonstrated in more detail.

  FIG. 2 is an explanatory view showing a first mode of forming an organic semiconductor thin film of an organic thin film transistor by the thin film forming method according to the present invention.

  First, as shown in FIG. 2 (a), a gate electrode 112 is formed on a support 111, an insulating layer 113 is formed, and a source electrode 114 and a drain electrode 115 are respectively formed thereon. Prepare 1

  Next, as shown in FIG. 2B, the ink 2 containing the organic semiconductor material is formed in a region (base material surface 10) extending from the surface of the source electrode 114 of the base material 1 to the surface of the drain electrode 115 through the surface of the insulating layer 113. Is granted.

  Next, as shown in FIG. 2 (c), the substrate surface 10 is irradiated with high illuminance light to heat and dry the ink 2 applied to the substrate 1, as shown in FIG. 2 (d). The organic semiconductor layer 116 (thin film 3) containing the organic semiconductor material is formed, and the organic thin film transistor 101 according to the first aspect is obtained.

  Since the obtained organic thin film transistor includes the organic semiconductor layer 116 (thin film 3) produced by the thin film formation method according to the present invention, homogenization of the organic semiconductor layer 116 and improvement of flatness are realized with good reproducibility. The transistor performance is improved stably. In addition, because high-intensity light is used, the ink can be heated and dried in a short time, and the effect of preventing deformation and modification of other components can be obtained, which also improves the transistor performance stably. Contribute to.

  3-5 is explanatory drawing which shows the 2nd-4th aspect of the organic thin-film transistor formed by the thin film formation method which concerns on this invention, respectively. The effects of the first aspect described above are also exhibited in the second to fourth aspects.

  In the second mode of FIG. 3, first, as shown in FIG. 3A, a gate electrode 112 is formed on a support 111, and an insulating layer 113 is formed on the gate electrode 112 and the support 111. A base material 1 is prepared.

  Next, as shown in FIG. 3B, the ink 2 containing an organic semiconductor material is applied to the surface of the insulating layer 113 (base material surface 10) of the base material 1.

  Next, as shown in FIG. 3 (c), the substrate surface 10 is irradiated with high illuminance light to heat and dry the ink 2 applied to the substrate 1, and as shown in FIG. 3 (d). Then, the organic semiconductor layer 116 (thin film 3) is formed.

  Next, as shown in FIG. 3E, the organic thin film transistor 102 according to the second aspect is obtained by forming the source electrode 114 and the drain electrode 115 so as to be in contact with the organic semiconductor layer 116.

  In the third mode of FIG. 4, first, as shown in FIG. 4A, the substrate 1 formed by forming the source electrode 114 and the drain electrode 115 on the support 111 is facilitated.

  Next, as shown in FIG. 4B, the ink 2 containing the organic semiconductor material in a region (base material surface 10) extending from the surface of the source electrode 114 of the base material 1 to the surface of the drain electrode 115 via the surface of the support 111. Is granted.

  Next, as shown in FIG. 4C, the base material surface 10 is irradiated with high illuminance light to heat and dry the ink 2 applied to the base material 1, as shown in FIG. 4D. Then, the organic semiconductor layer 116 (thin film 3) is formed.

  Next, as shown in FIG. 4E, an insulating layer 113 is formed on the organic semiconductor layer 116 (thin film 3), and a gate electrode 112 is further formed thereon, whereby the organic thin film transistor according to the third aspect is formed. 103 is obtained.

  In the fourth mode of FIG. 5, first, as shown in FIG. 5A, a base material 1 made of a support 111 is prepared.

  Next, as shown in FIG. 5B, the ink 2 containing the organic semiconductor material is applied to the surface of the substrate 1 (substrate surface 10).

  Next, as shown in FIG. 5C, the base material surface 10 is irradiated with high illuminance light to heat and dry the ink 2 applied to the base material 1, as shown in FIG. 5D. Then, the organic semiconductor layer 116 (thin film 3) is formed.

  Next, the source electrode 114 and the drain electrode 115 are formed so as to be in contact with the organic semiconductor layer 116 (thin film 3), and the gate electrode 112 is sequentially formed thereon via the insulating layer 113, whereby the fourth aspect is achieved. An organic thin film transistor 104 is obtained.

  In the present invention, it has been described above that the substrate 1 preferably has a layer that absorbs high illuminance light. However, in the process for producing the organic thin film transistor shown in the first aspect of FIG. Since the substrate 1 includes the gate electrode 112, the source electrode 114, and the drain electrode 115 made of an electrode material in the vicinity of the ink 2, these electrodes function as a layer that absorbs high illuminance light. The effect is even more pronounced. That is, in the example of FIG. 2, the gate electrode 112 that has absorbed the high illuminance light contributes to the heating and drying of the ink 2 through the insulating layer 113, while the source electrode 114 and the drain electrode 115 have absorbed the high illuminance light. In addition, by directly adjoining the ink 2, it contributes to heat drying of the ink 2.

  In addition, also when the organic thin film transistor shown in the second mode in FIG. 3 is manufactured, the gate electrode 112 can function as a layer that absorbs high illuminance light. That is, the gate electrode 112 that has absorbed the high illuminance light contributes to the heat drying of the ink 2 through the insulating layer 113.

  Furthermore, when the organic thin film transistor shown in the third embodiment in FIG. 4 is manufactured, the source electrode 114 and the drain electrode 115 can function as a layer that absorbs high illuminance light. That is, the source electrode 114 and the drain electrode 115 that have absorbed high illuminance light are directly adjacent to the ink 2, thereby contributing to heating and drying of the ink 2.

  In the above description, the case where the organic semiconductor thin film of the organic thin film transistor is formed by the thin film forming method according to the present invention has been described. However, the present invention is not limited to this, and other components of the organic thin film transistor, for example, the gate electrode 112, the insulating layer It is also preferable that the 113, the source electrode 114, the drain electrode 115, etc. are formed by the thin film forming method according to the present invention.

  Specifically, when the gate electrode 112, the source electrode 114, and the drain electrode 115 are formed, an ink containing a conductive material such as conductive fine particles or a conductive polymer can be used as the ink 2, and the insulating layer 113 is used. In forming the ink, an ink containing an insulating material can be used.

  In addition, the configuration of the organic thin film transistor manufactured by the thin film forming method according to the present invention is not limited to the configuration of the organic thin film transistors 101, 102, 103, and 104 shown in the first to fourth embodiments, and other configurations are possible. It can be preferably used for the preparation of the organic thin film transistor provided, and the effects of the present invention can be obtained.

  In the present invention, it is also preferable to blow air around the ink 2 at the time of irradiation with high illuminance light. As a result, the solvent vapor generated along with the drying of the ink 2 due to the irradiation of the high illuminance light can be removed from the vicinity of the ink 2 to further accelerate the drying, and the effects of the present invention can be exhibited more remarkably. In particular, in the present invention, the drying speed of the ink 2 by irradiation with high illuminance light is fast, and the solvent vapor is rapidly generated along with this, so the effect of removing this by blowing is great.

  The timing for starting the blowing is preferably between after applying the ink 2 to the substrate 1 and before or during the irradiation of the high illuminance light. In addition, when the application method of the ink 2 is not easily affected by the blowing, the blowing may be performed before the ink 2 is applied to the substrate 1. The blowing is continued at least during the irradiation of the high illuminance light, and preferably continues until the irradiation of the high illuminance light is completed.

  The thin film forming apparatus used in the thin film forming method according to the present invention described above includes a mechanism for applying ink onto the substrate, and heating the ink by irradiating the substrate surface with high illuminance light before the ink dries. Those having a drying mechanism (sometimes referred to as high illumination light irradiation means) can be preferably used.

  FIG. 6 is a schematic side view of an essential part showing an example of a thin film forming apparatus according to the present invention, and FIG. 7 is a plan view thereof.

  The thin film forming apparatus shown in FIGS. 6 and 7 incorporates a high illuminance light irradiation means in the configuration of a normal ink jet recording apparatus (mechanism for applying ink onto a substrate).

  6 and 7, the thin film forming apparatus 4 includes a carriage 41 that can be moved relative to the substrate 1 by a driving unit (not shown). The carriage 41 includes an inkjet head 42 and a high-illuminance light irradiation unit 43. And equipped. Here, the carriage 41 is described as moving in the left direction (arrow direction) in the figure with respect to the base material 1 along a guide rail (not shown).

  Here, the high-illuminance light irradiation means 43 is equipped with two xenon flash lamps 43a and 43b, and one xenon flash lamp 43a is closer to the inkjet head 42 side (upstream side in the movement direction) than the other xenon flash lamp 43b. It is arranged in. Reference numerals 431a and 431b denote optical filters provided in the xenon flash lamps 43a and 43b.

  Further, an air supply unit 44 and an exhaust unit 45 are provided before and after the high illuminance light irradiation unit 43 on the downstream side of the carriage 41 in the traveling direction from the inkjet head 42. The air supply from the air supply means 44 is exhausted by the exhaust means 45, so that a blast of laminar flow can be formed between the high illuminance light irradiation means 43 and the substrate surface. Each of the air supply means 44 and the exhaust means 45 can be constituted by a fan or the like. Reference numeral 46 denotes a rectifying unit for promoting the laminar flow of the air blow, and is provided over a region from the air supply means 44 to the exhaust means 45.

  When thin film formation is performed using the thin film forming apparatus 4 having the above-described configuration, the inkjet head 42 of the carriage 41 that moves relative to the base material 1 in the left direction (the arrow direction in the drawing) Ink 2 is applied to the substrate surface 10 of the material 1.

  Thereafter, when the carriage 41 further moves to the left, the ink 2 applied to the substrate surface 10 is heated and dried by receiving irradiation of high illuminance light from the xenon flash lamps 43a and 43b. Become. The solvent vapor generated with the drying is suitably removed by the air generated by the air supply means 44, the exhaust means 45, and the rectifying unit 46, and the drying is further promoted.

  In the above description, the case where the configuration of the ink jet recording apparatus is used as the mechanism for applying ink onto the base material has been described. However, the present invention is not limited to this, and any mechanism can be used.

  Examples of the present invention will be described below, but the present invention is not limited to such examples.

Example 1
The base material surfaces 114 and 115 (FIG. 2) of the base material 1 shown in FIG. 2 are printed with an ink containing 4.0% by weight of a thienothiophene low molecular semiconductor as an organic semiconductor material and 96.0% by weight of tetralin as a solvent. (Source electrode and drain electrode) was applied so that the applied amount was 320 pL. The ink viscosity was 1.8 mPa · s as measured by a vibration viscometer.

From 30 seconds after application of the ink, irradiation of high illuminance light with a xenon flash was performed for 30 seconds, and the ink was dried by heating to obtain a thin film. The xenon flash lamp uses a Hamamatsu Photonics 60W xenon flash lamp L7684, voltage 1000 V (input voltage 60 W), emission frequency 100 Hz, exposure surface output 1 W / 50 mmφ, pulse width 2.1 μs, (illuminance on the substrate surface; 400 mW / equivalent to cm ² ).

  An optical micrograph of the obtained thin film is shown in FIG.

(Comparative Example 1)
In Example 1, a thin film was obtained in the same manner as in Example 1 except that high-illuminance light was not irradiated.

  An optical micrograph of the obtained thin film is shown in FIG.

  8A and 8B, Sa represents a three-dimensional arithmetic surface roughness, and Sz represents a three-dimensional maximum value (a difference in height between the highest peak and the lowest valley).

<Evaluation>
From the results shown in FIGS. 8A and 8B, in Example 1 in which the ink was heated and dried by irradiation with high illuminance light, suppression of dot diameter reduction, elimination of cracks at the crystal edge, and unevenness in film thickness were reduced. The effect to do can be confirmed.

(Example 2)
In Example 1, ink was applied to the base material surface 10 (region straddling the two silver electrodes (source electrode and drain electrode)) of the base material 1 in the same manner as shown in FIG. In addition to an ink containing 2.0% by weight of a thienothiophene based low molecular semiconductor as a solvent, cyclohexylbenzene (abbreviation: CHB) as a solvent, 50.0% by weight and 48.0% by weight of tetralin, The illuminance on the material surface was changed as shown in FIG. 9, and after 25 seconds from ink landing, offline light heating was performed to obtain a thin film in the same manner as in Example 1. The ink viscosity was 2.1 mPa · s.

  In addition to the same exposure conditions as in Example 1 (pulse width, frequency, time), the conditions for changing the voltage of the xenon lamp were also added.

  An optical micrograph of the obtained thin film is shown in FIG. In FIG. 9, a test example that is not irradiated with high illuminance light is a comparative example.

Moreover, the exposure illumination intensity (all wavelengths [mW / cm < ² >]) shown in FIG. 9 is the value converted from UVPF-A1 (365 nm) peak illumination intensity measured by Eye Graphics Co., Ltd. (Examples 3 and 4). The exposure illuminance in FIGS. 10 and 11 showing the results is also the same).

(Example 3)
In Example 2, the ink was mixed with 1.0 wt% of a blended organic semiconductor composed of a low molecular organic semiconductor and a high molecular organic semiconductor as an organic semiconductor material, 49.0 wt% of cyclohexylbenzene (abbreviation: CHB) as a solvent, and tetralin. A thin film was obtained in the same manner as in Example 1, except that the amount of ink applied and the illuminance on the substrate surface were changed as shown in FIG. The ink viscosity was 3.5 mPa · s.

  An optical micrograph of the obtained thin film is shown in FIG. In addition, in FIG. 10, the test example which is not irradiating with high illumination light is a comparative example.

Example 4
Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co-bithiophene] (abbreviation: F8T2) 1.0 wt% as an organic semiconductor material, 49.0 wt% of cyclohexylbenzene (abbreviation: CHB) as a solvent, and In place of the ink containing 50.0% by weight of tetralin, the amount of ink applied and the illuminance on the substrate surface were changed as shown in FIG. The ink viscosity was 4.4 mPa · s.

  An optical micrograph of the obtained thin film is shown in FIG. In addition, in FIG. 11, the test example which is not irradiating with high illumination light is a comparative example.

<Evaluation>
From the results of FIGS. 9 to 11, it is understood that the ink fluidity between the source electrode and the drain electrode is prevented by performing irradiation with high illuminance light.

In particular, when the illuminance on the substrate surface has at least 100 mW / cm ² , it can be seen that ink fluidity is more remarkably prevented.

  FIG. 9 shows that the thienothiophene-based semiconductor / CHB / tetralin ink prevents the liquid from being drawn into the electrodes as the illuminance of light heating increases, and the dot diameter between the channels increases (can maintain the original size). The same effect can be confirmed also in the case of blended semiconductor / tetralin ink (FIG. 10) and in the case of F8T2 / CHB ink (FIG. 11).

  In the above-described embodiments, the application of 100 to 320 pL of droplets is illustrated. However, the present invention is not limited to this. For example, when the droplet size is smaller, the illuminance of the light source and the integrated light amount are smaller. However, the effect of flattening the thin film can be obtained.

1: Base material 10: Base material surface (base material surface)
2: ink 3: thin film 101, 102, 103, 104: organic thin film transistor 111: support 112: gate electrode 113: insulating layer 114: source electrode 115: drain electrode 116: organic semiconductor thin film 4: thin film forming apparatus 41: carriage 42 : Inkjet head 43: High illumination light irradiation means 43a, 43b: Xenon flash lamps 431a, 431b: Optical filter 44: Air supply means 45: Exhaust means 46: Rectification unit

Claims (9)

In a method for forming a thin film coating film by applying ink on a substrate, after applying the ink on the substrate, before the ink is dried , flash light is applied to the substrate surface for one irradiation time. The range is from microseconds to 2 milliseconds, an intermittent time of 0.5 milliseconds to 100 milliseconds is provided between each irradiation time, and the ink is heated and dried by continuously irradiating 10 times to 30000 times. A thin film forming method. Illuminance of the flash light on the substrate surface is 100 mW / cm ² ~ 400mW / cm ² The thin film forming method according to claim 1, wherein: Method of applying ink to a substrate surface, a thin film forming method according to claim 1 or 2, characterized in that the ink jet method. Thin film forming method according to any one of claims 1 to 3, wherein the ink is characterized by containing an organic semiconductor material. Wherein in the vicinity of the substrate surface, a thin film forming method according to any one of claims 1-4, characterized in that there is a layer that absorbs the high intensity light to impart the ink. 6. The method of forming a thin film according to claim 5, wherein the layer that absorbs high illuminance light is an electrode material. The layer that absorbs the high illuminance light has an absorbance of 0.01 or more and 3 or less in a part or all of the light source spectrum of the flash light, and
The layer that absorbs high illuminance light is in direct contact with the ink applied on the substrate, or is not in contact with the ink at a distance of 2 μm or less from the ink application position. The thin film forming method according to claim 5 or 6.   The method of forming a thin film according to claim 1, wherein the viscosity of the ink is in a range of 1 mPa · s to 30 mPa · s. In an apparatus for forming a thin film coating film by applying ink onto a substrate, the apparatus applies a flash light to the substrate surface before the ink is dried . The irradiation time is in the range of 1 microsecond to 2 milliseconds, an intermittent time of 0.5 milliseconds to 100 milliseconds is provided between each irradiation time, and the ink is heated and dried by continuously irradiating 10 times to 30000 times. A thin film forming apparatus having a mechanism for

Images