JPWO2015102110A1 - Functional material lamination method and functional material laminate - Google Patents

Abstract

The present invention realizes homogenization of electrical characteristics even when layered structures such as organic TFTs and OLED light emitting elements are formed using a printing method, even when layered printing is performed with a functional ink having a particularly high solvent ratio. A first functional material ink containing a first solvent and a first functional material is applied to a substrate 1 for the purpose of providing a functional material lamination method and a functional material laminate formed thereby. In the method of laminating the functional material, the second functional material ink containing the second solvent and the second functional material is formed on the first functional material layer 2 on which the coating film is formed by printing. Before forming the coating film of the second functional material ink, it has a process of controlling the first functional material layer 2, and the process has a second solvent of the second functional material ink in the first functional material layer 2 When the 3 is dipped, the second solvent contacts the first functional material layer 2. Corners, are over time the process of controlling the first functional material layer 2 so that the state substantially unchanged.

Description

  TECHNICAL FIELD The present invention relates to a functional material laminating method and a functional material laminate, and more specifically, a functional material composed of a plurality of layers such as an organic TFT or an OLED light-emitting element by applying or printing an ink containing a solvent and a functional material on a substrate. The present invention relates to a functional material laminating method and a functional material laminating body that can make the film quality at the interface of the laminated body uniform.

  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. Attempts have been made to print devices.

  Formation of organic thin films such as transparent electrodes, light-emitting layers and organic layers of OLEDs, semiconductor layers of organic transistors, etc., from the production by the conventional vacuum method, to form a coating film by coating and printing under atmospheric pressure, especially Lamination using an ink jet method has been studied. 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.

  A process of patterning and laminating a plurality of functional materials by printing or coating without using a vacuum process is called a “wet process”, and an ink in which a functional material is dissolved or dispersed in a solvent is overcoated.

  In the application as described above, the solid content and the wet film thickness of the functional material are usually adjusted so that the dry coating thickness of the functional material layer is about 1 to several hundred nm.

  As a method for laminating functional material inks, screen printing, offset printing, flexographic printing, gravure printing, and inkjet printing are known as methods for printing pattern shapes, in addition to coating methods such as die coater coating and capillary coating. Above all, the ability to perform patterning without plateless digital, the ability to apply as much material as needed to the required locations, and the ability to print low-viscosity inks make inkjet printing suitable for applying functional thin films, and various R & D efforts are underway. It has been broken. For example, functional thin films such as 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, an organic semiconductor layer, and the like can be given.

  As a technique for processing the formed functional material, the background art of Patent Document 1 discloses a method of converting a precursor film coated and formed using a soluble organic semiconductor precursor into an organic semiconductor by heat treatment. Has been.

  In addition, in making functional materials into inks, various additives for imparting printability are blended in addition to the functional material as the main component in order to have printability suitable for each printing method. Since these additives affect the printability of the functional material provided on the provided functional layer and the electrical properties of the finished laminate, several attempts have been made.

  Japanese Patent Laid-Open No. 2004-228688 describes that a nonionic surfactant is added to the silver particle-containing ink used for reversal printing to make the ink nonionic, thereby preventing printability and TFT characteristic deterioration.

  Patent Document 3 is used as a bank for forming a liquid repellent layer by depositing a liquid repellent component added to a printed source electrode and drain electrode on the surface of the electrode by baking to form a semiconductor film. Is disclosed. At this time, it is described that the G insulating film is protected.

  Patent Document 4 discloses that an electrode surface is made lyophilic and a semiconductor is formed by ink jet printing with an ink surface tension suitable for a short channel pattern.

JP 2004-247716 A JP 2010-219447 A JP 2011-54877 A JP 2010-93092 A

  However, even if the method described in the above-mentioned patent document is used, there is room for further improvement in terms of suppressing variations in electrical characteristics of laminated devices, for example, variations in characteristics of organic semiconductors, at a high level. In particular, when an organic semiconductor is printed on an electrode or an insulating film by an ink jet method, there is a great demand for further homogenization of TFT characteristics. For example, in an organic semiconductor produced by a printing process, a large variation among elements in various performances such as mobility, on-current, and voltage threshold is expected to be a device capable of flexible and low-temperature processing. This is one of the obstacles.

  The present inventor has provided a second functional material for forming an upper layer in order to laminate the second functional material layer on the first functional material layer serving as a base and to laminate the second functional material layer. Solvent resistance of the lower first functional material layer or the solvent type in the second functional material ink that forms the upper layer so that the lower first functional material layer is not dissolved or swollen by the solvent in the ink. Was considered. For example, by appropriately selecting good and poor solvents for each functional material layer and maintaining a uniform interface between the functional material layers, we tried to keep the film quality of the laminate uniform and suppress variations in electrical characteristics. .

  In addition, in order to provide solvent resistance in the second functional material ink forming the upper layer, it was also considered to perform a process such as a crosslinking reaction after forming the first functional material layer as the lower layer.

  However, considering the solvent resistance of the material in this way, it has been found that there are many cases where the electrical characteristics of the laminated device will vary even if the device is kept homogeneous by avoiding the interface between the functional material layers. It was. In particular, it was found that when the solid content of the functional material ink laminated on the functional material layer is small and the ratio of the solvent is large, it is difficult to obtain uniform electrical characteristics.

  Conventionally, as a measure for improving variations in TFT elements by printing, many studies have been made focusing on semiconductor film quality. Particularly in the case of a low molecular type organic semiconductor, the charge / electron mobility largely depends on the crystal structure of the coating film, so that the control of the semiconductor drying process is important. On the other hand, many polymer-type organic semiconductors are formed in an amorphous state, and the effect of the semiconductor drying / deposition process on the film quality itself such as mobility is relatively small. However, an interface between different materials such as an electrode or an insulating film and a semiconductor layer is a part related to charge transfer, and thus has a great influence on characteristics regardless of the type of semiconductor.

  Therefore, the present invention makes it possible to homogenize electrical characteristics even when a laminated structure such as an organic TFT or an OLED light-emitting element is formed using a printing method, even if laminated printing is performed using a functional ink having a high solvent ratio. It is an object of the present invention to provide a functional material stacking method capable of realizing the above and a functional material stack formed thereby.

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

  The above problems are solved by the following inventions.

1.
The second solvent and the second function are formed on the first functional material layer formed by coating or printing the first functional material ink containing the first solvent and the first functional material on the substrate. In the method of laminating a functional material for forming a coating film by printing the second functional material ink containing the material,
A process of controlling the first functional material layer before forming the coating film of the second functional material ink;
In the process, when the second solvent of the second functional material ink is immersed in the first functional material layer, the contact angle of the second solvent with respect to the first functional material layer Is a process for controlling the first functional material layer so that the first functional material layer is not substantially changed over time.

2.
2. The method for laminating functional materials according to 1 above, wherein the second functional material is an organic semiconductor material.

3.
The second solvent and the second function are formed on the first functional material layer formed by coating or printing the first functional material ink containing the first solvent and the first functional material on the substrate. In the method of laminating a functional material for forming a coating film by printing the second functional material ink containing the material,
The first functional material is a conductive material, and the second functional material is a semiconductor material;
A process of controlling the first functional material layer before forming the coating film of the second functional material ink;
In the process, when the second solvent of the second functional material ink is immersed in the first functional material layer, an output gradient obtained by photoelectron yield spectroscopy measurement of the first functional material layer is increased. A method of laminating a functional material, which is a process of controlling the first functional material layer so that it does not change substantially with time.

4).
4. The functional material laminating method according to 1, 2, or 3, wherein the first functional material ink is printed by an offset printing method.

5.
5. The method for laminating a functional material according to any one of 1 to 4, wherein the second functional material ink is printed by an inkjet method.

6).
The process for controlling the first functional material layer includes a cleaning process using a solvent, a solution processing process including a third functional material, an annealing process using a solvent vapor, an ozone processing process, a plasma processing process, a CVD processing process, and a vapor deposition processing process. 6. The functional material laminating method according to any one of 1 to 5, wherein any one or two or more of a sputtering treatment process and an active energy ray irradiation treatment process are combined.

7).
The process for controlling the first functional material layer includes a cleaning process using a solvent, and the solvent contains a good solvent for the first functional material. .

8).
The process for controlling the first functional material layer includes a cleaning process using a solvent, and the solvent includes a good solvent for the second functional material. .

9.
The process for controlling the first functional material layer includes a cleaning process using a solvent, and the solvent includes a good solvent for the first functional material and a good solvent for the second functional material. A method for laminating a functional material according to any one of the above.

10.
A functional material laminate obtained by the functional material lamination method according to any one of 1 to 9 above.

Schematic cross-sectional view illustrating an example of a method for laminating functional materials of the present invention Schematic sectional view schematically showing an example of a laminated structure of thin film transistors as a functional material laminate Schematic cross-sectional view for explaining an example of forming a laminated structure of thin film transistors by the functional material lamination method of the present invention Diagram showing an example of output slope measurement obtained by photoelectron yield spectroscopy

(First embodiment)
In the functional material laminating method according to the first embodiment of the present invention, a first functional material ink containing a first solvent and a first functional material is applied to a substrate by coating or printing to form a first coating. On the functional material layer, a second functional material ink containing a second solvent and a second functional material is formed by printing to form a first functional material layer (lower layer) on the substrate. The second functional material layer (upper layer) is laminated.

  And it has the process which controls a 1st functional material layer, before forming a coating film with a 2nd functional material ink.

  FIG. 1 shows a state in which a second solvent 3 of a second functional material ink is immersed in a first functional material layer 2 having a coating film formed on a substrate 1. By the immersion treatment, the second solvent 3 forms hemispherical droplets on the surface of the first functional material layer 2. In the present invention, the process of controlling the first functional material layer is performed when the second functional material ink second solvent 3 is immersed in the first functional material layer 2 as shown in FIG. It is a process for controlling the first functional material layer 2 so that the contact angle θ of the second solvent 3 to the first functional material layer 2 does not substantially change with time. To do.

  Thereby, when the coating film is formed on the first functional material layer by printing the second functional material ink, the contact angle of the second solvent of the second functional material ink with respect to the first functional material layer is changed. Can be prevented. As a result, when a laminated structure such as an organic TFT or an OLED light-emitting element is formed using a printing method, even if laminated printing is performed with a functional ink having a high solvent ratio, such as an inkjet method or a coating method, Homogenization of characteristics can be realized. That is, when the second functional material layer is formed using an ink having a high solvent ratio with respect to the first functional material layer, the effect of homogenizing the electrical characteristics becomes remarkable.

  The ink having a high solvent ratio is not particularly limited, but is a low-viscosity ink suitable for an inkjet method, spin coating application, slit die coating application, etc., and the content of the functional material is 0.1 wt% to It is preferable that it is 30 wt% or the range of the solvent is 70 wt% or more.

  The present invention is directed to two layers: a first functional material layer that is laminated on a base material, and a second functional material layer that is laminated by forming a coating film of functional material ink thereon by printing. . Therefore, the functional material layer laminated on the substrate is not limited to two layers, and may be three or more layers. When three or more layers are stacked, the stacking method of the present invention can be applied when stacking two layers (upper layer and lower layer) stacked adjacent to each other in the vertical direction.

  Further, the upper layer and the lower layer are not limited to one layer each, and there may be a plurality of layers. Therefore, for example, a plurality of layers may be stacked on the lower layer of one layer, or the upper layer of one layer may straddle the plurality of layers arranged in parallel. It may be laminated. Furthermore, the further upper layer may be laminated | stacked so that it may straddle both the two layers laminated | stacked up and down.

  The first functional material layer is formed on the substrate by applying or printing a first functional material ink containing a first solvent and a first functional material.

  Examples of the method for forming the first functional material layer by applying the first functional material ink include dipping, spin coating, knife coating, bar coating, blade coating, squeeze coating, reverse roll coating, and gravure. Known coating methods such as roll coating, curtain coating, spray coating, and die coating can be used.

  Moreover, as a method of forming the first functional material layer by coating the first functional material ink, known printing methods such as screen printing, offset printing, flexographic printing, gravure printing, inkjet printing, etc. Can be used. Among these, the offset printing method is preferable. The offset printing method is not particularly limited, but the microcontact printing method, the reversal printing method, and the like are preferable as the semiconductor array printing method because the flatness of the coating film is good and high-resolution printing can be handled.

  In this way, after the first functional material layer is formed on the substrate, the second functional material ink containing the second solvent and the second functional material is formed thereon by printing. As described above, before forming the coating film by printing the second functional material ink, the contact angle of the second solvent in the second functional material ink with respect to the first functional material layer is changed over time. The process (process) which controls so that it will be in the state which does not change substantially is performed.

  The timing for executing this process is preferably the timing from the time when the first functional material ink is applied on the substrate to the time before the second functional material ink is formed by printing. As a more preferable timing, after forming a dry coating film in which the first solvent in the first functional material ink is dried, or after forming a cured coating film obtained by curing the first functional material ink, The second functional material ink has a timing before the coating film is formed by printing. In particular, it is preferable to execute such a process at a timing immediately before printing the second functional material ink. This makes it easy to prevent contamination of the first functional material ink, for example. Effects such as easy to prevent fluctuations can be obtained.

  By performing such a process, the first functional material layer has a contact angle θ of the second solvent with respect to the first functional material layer when the second solvent in the second functional material ink is dipped. However, the physical properties of the surface are controlled so that they do not substantially change with time.

  Note that the state in which the contact angle θ does not substantially change with time means that the contact angle is 10 minutes after the second solvent of the second functional material ink is applied on the first functional material layer. It means that the absolute value of the change amount of θ is kept at 10 ° or less. When the volatility of the second solvent is sufficiently small, the achievement of the control can be confirmed by dropping the solvent onto the first functional material layer and following the change with time of the contact angle as it is. When the volatility of the second solvent is large, the first functional material is immersed in the second solvent for 10 minutes, and after removing the solvent by drying, the second solvent is dropped again to measure the contact angle. Comparing changes in the front and rear contact angles can confirm the achievement of control.

  Specific processes include a cleaning process using a solvent, a solution processing process including a third functional material, an annealing process using a solvent vapor, an ozone processing process, a plasma processing process, a CVD processing process, a vapor deposition processing process, a sputtering processing process, and an activity. Examples include an energy beam irradiation treatment process, and any one process selected from these or two or more processes can be used in appropriate combination.

  The solvent cleaning process is a process of cleaning the surface of the first functional material layer with a solvent. The solvent is not particularly limited, but various solvents such as pure water, various alcohols, glycols, glycol ethers, ketones, ethers, esters, hydrocarbons, halogen solvents and the like can be preferably exemplified. Moreover, you may use together 1 type, or 2 or more types of solvents as a solvent. The solvent preferably has a high purity.

  It is preferable that the solvent used in the cleaning process with the solvent contains a good solvent for the second functional material. As a result, the components contained in the first functional material are homogenized by dissolution or washing, and fluctuations in the contact angle of the second functional material ink are suppressed. As a result, the second functional material layer is laminated in a uniform shape. The crystal orientation of the functional material can be homogenized. In addition, it is possible to prevent the impurities contained in the first functional material layer from diffusing into the second functional material layer and affecting the electrical characteristics. These effects become more remarkable as the solvent ratio of the second functional material ink is higher. When the second functional material layer is an organic semiconductor layer, a good solvent for the organic semiconductor is used as a cleaning solvent, for example, a solvent such as xylene, toluene, anisole, mesitylene, tetralin, cyclohexylbenzene, mesitylene, chloroform, dichlorobenzene, etc. Can be preferably exemplified. As the good solvent for the second functional material, it is also preferable to use, for example, the second solvent of the second functional material ink.

  In the present invention, the good solvent for the functional material means a solvent that can easily form a homogeneous system by dispersing the functional material in the solvent in a broad sense, and a solvent that easily dissolves the functional material in a narrow sense. Point to. In the present invention, for example, relatively insoluble functional materials such as organic semiconductor materials and organic light-emitting materials are also targeted. Therefore, any solvent that can dissolve 0.2 wt% or more of functional materials at 25 ° C. is acceptable. It can be suitably used as a solvent. For example, in the case of a relatively easily soluble functional material, a solvent capable of dissolving 1.0 wt% or more of the functional material at 25 ° C. is suitable as a good solvent.

  Moreover, it is also preferable that the solvent used in the cleaning process with the solvent contains a good solvent for the first functional material. As a result, there is an effect that the surface can be homogenized by cleaning a trace amount of impurity components contained in the first functional material ink and components that affect electrical characteristics such as additives for obtaining printability. In the case where the first functional material layer is a source / drain electrode of a TFT, these impurity components affect carrier injection into the semiconductor. Therefore, by removing or homogenizing by a control process, variation is small, and Devices with good characteristics can be manufactured. As the good solvent for the first functional material, it is also preferable to use, for example, the first solvent of the first functional material ink.

  Furthermore, it is preferable that the solvent used in the cleaning process with the solvent includes a good solvent for the first functional material and a good solvent for the second functional material. As a result, the surface state of the first functional material layer is homogenized to improve electrical characteristics, and impurities are prevented from being mixed into the second functional material ink even when laminated with the solvent of the second functional material ink. The above-described effect that the electrical characteristics that are uniform and have a small characteristic variation can be obtained is favorably achieved. At this time, the solvent may contain a good solvent for the first functional material and one kind of solvent that also serves as the good solvent for the second functional material, or may be a good solvent for the first functional material. It may include both a solvent and a solvent that is a good solvent for the second functional material.

  The solution treatment process containing the third functional material is a process of treating the surface of the first functional material layer by bringing it into contact with the solution containing the third functional material. As the third functional material, a material that exerts a physical or chemical action on the surface of the first functional material layer is preferably used. Although not particularly limited, a SAM (Self-assembled monolayer) is used. ) The process etc. can be illustrated preferably. It is also preferable to leave the third functional material or a substance generated from the third functional material on the surface of the first functional material layer. For example, as the third functional material, it is also preferable to select and use a material capable of modifying an arbitrary functional group on the surface of the first functional material layer. For example, a compound having a functional group such as a thiol group that can be fixed by reacting with the surface of a metal or the like constituting an electrode or the like is reacted with the surface by wet treatment, and a functional group such as a thiol group is formed on the surface. A technique for modifying is widely known. Such SAM processing has been a problem because there are many cases in which variation is increased even if the characteristic value of the TFT can be improved. This was particularly remarkable for electrodes provided by printing. However, as in the present invention, before the coating film of the second functional material ink is formed, the SAM treatment surface is formed so that the contact angle of the solvent of the second functional material ink is not substantially changed, or SAM. The effect of the present invention can be obtained by forming the SAM treatment surface so that the output slope obtained by photoelectron yield spectroscopy measurement of the treatment surface does not substantially change with time.

  The annealing process using the solvent vapor is a process of annealing the surface of the first functional material layer by bringing it into contact with the solvent vapor. Thereby, the orientation state of molecules on the surface of the first functional material layer can be changed. Although it does not specifically limit as a solvent, The good solvent of a 1st functional material, the good solvent of a 2nd functional material, etc. can be illustrated preferably. From the viewpoint of annealing the surface of the first functional material layer, it is also preferable to select a solvent having a high affinity with the surface of the first functional material layer.

  The ozone treatment process is a process in which the surface of the first functional material layer is brought into contact with ozone. Thereby, the surface of the first functional material layer can be chemically modified.

  The plasma treatment process is a process for treating the surface of the first functional material layer with plasma. Thereby, the surface of the first functional material layer can be chemically modified. It is also preferable to perform the plasma treatment process in parallel with the ozone treatment process.

The CVD (Chemical Vapor Deposition) treatment process is a process in which chemical vapor deposition treatment is performed on the surface of the first functional material layer. Thereby, a film can be formed on the surface of the first functional material layer by a chemical reaction. The CVD process is not particularly limited, but for example, a plasma CVD process or a thermal CVD can be preferably exemplified. Although these materials used for CVD are not particularly limited, various metals such as Al and Cu, metal oxides, and source gases such as SiH ₄ / O ₂ can be preferably exemplified.

  The vapor deposition process is a process of performing a vapor deposition process on the surface of the first functional material layer. Thereby, a film can be formed on the surface of the first functional material layer. Specifically, physical vapor deposition (PVD: Physical Vapor Deposition) etc. can be illustrated preferably. Although it does not specifically limit as a material used for a vapor deposition process, Organic materials, Au, Cr other metal materials, etc. which have hole injection functions, such as PEDOT, can be illustrated preferably.

The sputter treatment process is a process in which the surface of the first functional material layer is sputtered. Thereby, a metal film can be formed on the surface of the first functional material layer. The metal forming the film may be an oxide or the like, and is not particularly limited, but ITO, Cr, Pt, Au, Cu, Ag, SiO ₂ , ZnO, and the like can be preferably exemplified.

  The active energy ray irradiation treatment process is a process of irradiating the surface of the first functional material layer with active energy rays. As the active energy ray, an energy ray capable of activating the surface of the first functional material layer can be preferably used. Although not particularly limited, microwaves, infrared rays, visible rays, ultraviolet rays, electron beams and the like can be preferably exemplified. By irradiating the active energy ray, for example, a substance constituting the surface of the first functional material layer can be changed. Specifically, for example, on the surface of the first functional material layer, an action of advancing the polymerization reaction or breaking the chemical bond can be given.

  The process for controlling the first functional material layer in the first embodiment preferably includes at least a cleaning process using a solvent. In particular, a solvent containing a good solvent for the second functional material is preferably used as the cleaning solvent.

  After such a process is performed on the first functional material layer, a second functional material ink is printed thereon.

  As the printing method of the second functional material ink, a known printing method similar to the printing method of the first functional material ink described above can be used. An ink jet printing method is preferable in that a material can be applied to a portion as much as necessary and printing can be performed even with a low viscosity ink.

  For example, the second solvent in the second functional material ink applied on the first functional material layer is dried to form a dry coating film, or the second functional material ink is cured to be cured. By using a film, the second functional material layer can be formed.

  In the present invention, the functional material laminate obtained by the functional material laminating method is a laminate that exhibits a specific function by laminating various functional materials into a plurality of layers on a substrate by the laminating method. Although not specifically limited, For example, OLED (organic light emitting diode) illumination, OLED (organic light emitting diode) display, TFT (thin film transistor), FPC (flexible printed circuit board), a touch panel etc. can be mentioned preferably.

  FIG. 2 schematically shows an example of a laminated structure of thin film transistors as such a functional material laminate. This laminated structure itself is known. In the figure, 10 is a base material, 11 is a gate electrode laminated on the base material 10, 12 is an insulator layer laminated on the gate electrode 11, 13 is a source electrode laminated on the insulator layer 12, 14 Is a drain electrode laminated on the insulator layer 12, and 15 is a semiconductor layer laminated on the insulator layer 12 and between the source electrode 13 and the drain electrode 14.

  The base material 10 is not particularly limited as long as it has insulating properties, and a known material can be appropriately used according to the purpose. For example, in addition to relatively hard and high heat resistant substrates such as glass substrates, ceramic substrates, metal substrates (eg metal thin film substrates), paper phenol substrates, paper epoxy substrates, nanocellulose fiber paper, It may be a substrate made of a mixture of two kinds such as a glass composite substrate and a glass epoxy substrate, or may be a resin substrate. Examples of the resin of the resin base material include polyimide, polyamide, polyethylene terephthalate, polyethylene naphthalate, and polyethersulfone. The substrate 1 may have a single layer structure or a multilayer structure, and an insulating coated conductive material or the like can also be used.

  The gate electrode 11 is not particularly limited as long as it is a conductive material. For example, metals such as Al, Au, Ag, Pt, Pd, Cu, Cr, Mo, In, Zn, and Mg, and oxides such as ITO and ZnO A conductive material, a conductive polymer such as PEDOT-PSS, or the like can be used. Further, a plurality of these materials may be used for lamination.

  The formation method of the gate electrode 11 is not particularly limited, and the gate electrode 11 can be formed by patterning using a photolithography method after forming a gate electrode material using a sputtering method, vapor deposition, or the like. Moreover, it can form using a mask vapor deposition method.

The insulator layer 12 can be made of an inorganic material such as SiO ² or SiN, or an organic material such as PVA, PVP, polyimide resin, or novolac resin. Further, a plurality of these materials may be used for lamination.

  The formation method of the insulator layer 12 is not particularly limited, and sputtering, vapor deposition, CVD, spin coating, ink jet printing, or the like can be used.

  Hereinafter, the present invention will be further described on the assumption that the first functional material layer is the source electrode 13 and the drain electrode 14 and the second functional material layer is the semiconductor layer 15.

  The source electrode 13 and the drain electrode 14 as the first functional material layer are laminated on the insulator layer 12 by coating or printing. That is, on the insulator layer 12 using a functional material ink (first functional material ink) including a solvent (first solvent) and an electrode material (first functional material) to be a source electrode and a drain electrode. The source electrode 13 and the drain electrode 14 are applied or printed by the method described above.

  Examples of the electrode material to be the source electrode 13 and the drain electrode 14 include metals such as Ag, Au, Pt, Pd, Cr, Se, and Ni, oxide conductive materials such as ITO and ZnO, and conductive polymers. Examples thereof include a conductive material that is dissolved or dispersed in an organic solvent or water.

  The solvent (first solvent) constituting the first functional material ink together with these electrode materials is not particularly limited, but is appropriately selected depending on the solute to be dispersed or dissolved. For example, PEDOT-PSS typically uses water, isopropyl alcohol (abbreviated as IPA), water-based Ag nanoinks, polar solvents such as water, ethanol, and IPA, and solvent-based Ag nanoinks typically use hydrocarbon solvents such as tetradecane.

  The source electrode 13 and the drain electrode 14 are formed by drying a solvent after forming a coating film on the insulator layer 12 by coating or printing so as to be separated from each other. The film thickness is appropriately set. In the case of coating method, ink jet printing, and screen printing, ink is applied directly on the insulator layer. In the case of gravure printing, flexographic printing, offset printing, etc., an electrode is formed by retransferring ink or semi-dry ink applied to a gravure plate, anilox roll, blanket or the like to an insulator layer.

  After the source electrode 13 and the drain electrode 14 are formed in this way, the semiconductor layer 15 as the second functional material layer is printed over the source electrode 13 and the drain electrode 14 and the insulator film 12. To form a coating film. That is, by using a functional material ink (second functional material ink) containing a solvent (second solvent) and a semiconductor material (second functional material), the source electrode 13, the drain electrode 14, and the insulator layer 12 are formed. The semiconductor layer 15 is printed over the top.

  As a semiconductor printing method, any of coating, ink jet, gravure, flexo, and offset methods can be applied, but an ink jet method that can apply ink to only a desired portion without waste is most suitable.

  The semiconductor material to be the semiconductor layer 15 is not particularly limited as long as it can be dissolved or dispersed in a solvent (second solvent). In addition to organic polymer materials, low molecular materials, hybrid types of low molecules and polymers, and the like can also be used. Moreover, the precursor of a semiconductor may be sufficient. Furthermore, organic-inorganic hybrid materials such as oxides and inorganic materials may be used.

  The solvent (second solvent) that constitutes the second functional material ink together with such a semiconductor material is not particularly limited, but in the case of an organic semiconductor, a low-polarity carbonization that provides sufficient solubility. A hydrogen-based solvent or a halogen-based solvent is used.

  Here, as shown in FIG. 3, before forming the coating film on the semiconductor layer 15, the source electrode 13 and the drain electrode 14, which are the second functional material layers, are connected to the source electrode 13 and the drain electrode 14. The process is performed so that the contact angle of the second solvent is not substantially changed with time.

  By performing such a process, the physical properties of the surface of the source electrode 13 and the drain electrode 14 are set so that the contact angle of the second solvent in the ink containing the semiconductor material does not substantially change with time. Is controlled. Thereby, when the semiconductor layer 15 is formed on the source electrode 13 and the drain electrode 14 by printing, variation in electrical characteristics is suppressed.

(Second Embodiment)
In the functional material laminating method according to the second embodiment of the present invention, the first functional material ink containing the first solvent and the first functional material is coated on the substrate or formed by printing. On the functional material layer, a second functional material ink containing a second solvent and a second functional material is formed by printing to form a first functional material layer (lower layer) on the substrate. The first functional material layer (upper layer) is laminated, and the first functional material layer has a process of controlling the first functional material layer before forming the coating film of the second functional material ink. Although the embodiments are the same, the first functional material is a conductive material, and the second functional material is a semiconductor material.

  In the above process, when the second solvent of the second functional material ink is immersed in the first functional material layer, the output slope obtained by the photoelectron yield spectroscopy measurement of the first functional material layer is It is a process for controlling the first functional material layer so that it does not change substantially with time.

  In addition, the state in which the output slope obtained by photoelectron yield spectroscopy measurement does not substantially change with time is the output slope measured before the immersion treatment when the immersion treatment with the second solvent is performed for 10 minutes, It means that the absolute value of the difference in output slope measured after the immersion treatment is kept at 10% or less.

Photoelectron yield spectroscopy can be performed, for example, by AC-2 or AC-3 from Riken Keiki Co., Ltd. As shown in FIG. 4, which is a measurement example, the output slope is an output intensity in a linear region with respect to irradiation energy (eV) above a threshold energy in photoelectron yield spectroscopy measurement of the first functional material layer (= It means the slope of (number of photoelectrons emitted) ^1/2 ). The change in the output slope can be determined from the difference in the output slope measured before and after the immersion treatment with the second solvent.

  In this way, when the second functional material ink is formed on the first functional material layer by printing, the electrical characteristics can be homogenized. In particular, when the solid content of the functional material ink laminated on the functional material layer is small and the ratio of the solvent is large, the effect of homogenizing the electrical characteristics becomes remarkable.

  In the second embodiment, for the same constituent elements as those of the first embodiment described above, the description in the first embodiment is used, and the description here is omitted.

  The specific means used in the process for controlling the first functional material layer in the second embodiment is not particularly limited, but means used in the process for controlling the first functional material layer in the first embodiment. Can be used alone or in combination. When the second solvent of the second functional material ink is immersed in the first functional material layer using such means, the output slope obtained by the photoelectron yield spectroscopy measurement of the first functional material layer is Therefore, the first functional material layer is controlled so as to be substantially unchanged.

  The process for controlling the first functional material layer in the second embodiment preferably includes at least a cleaning process using a solvent. In particular, a solvent containing a good solvent for the first functional material is preferably used as the cleaning solvent.

  As the conductive material that is the first functional material, the same electrode material as described above can be used.

  Further, the semiconductor material described above can be used as the semiconductor material that is the second functional material.

  In the present invention, it is also preferable to combine the first embodiment with the second embodiment. That is, in the second embodiment, as a control process, “when the second solvent of the second functional material ink is immersed in the first functional material layer, the photoelectron yield spectroscopy measurement of the first functional material layer is performed. The process of controlling the first functional material layer so that the output slope obtained in the above does not substantially change with time ”is executed. In addition to this process, the process according to the first embodiment is further performed. The control process, that is, “when the second solvent of the second functional material ink is immersed in the first functional material layer, the contact angle of the second solvent with respect to the first functional material layer It is also preferable to execute the “process for controlling the first functional material layer so as to be substantially unchanged”. Thereby, the electrical characteristics can be further homogenized.

  The method of combining the first embodiment with the second embodiment is not particularly limited. For example, as a control process of the second embodiment, a cleaning process using a solvent containing a good solvent for the first functional material is executed. In addition to this, as a control process of the first embodiment, a method of executing a cleaning process using a solvent including a good solvent for the second functional material is suitable.

  The order in which the control processes according to the second embodiment and the first embodiment are executed is not particularly limited.

  Further, for example, each control according to the second embodiment and the first embodiment is performed by executing a cleaning process using a solvent including both the good solvent of the first functional material and the good solvent of the second functional material. It is also preferable to run the processes simultaneously.

  In the present invention, the functional material used as the first or second functional material is not limited to the example described above, and for example, a semiconductor material, a light emitting material, a dielectric material, a conductive material, an insulating material, etc. are preferable. The first or second functional material can be appropriately selected from these. The functional material may be either an inorganic material or an organic material.

  In one preferred embodiment, for example, a conductive material (for example, a material for forming an electrode) or an insulating material (for example, a material for forming an insulating layer) is selected as the first functional material, and a semiconductor is selected as the second functional material. A material, luminescent material or dielectric material can be selected.

  In the second embodiment, a conductive material (for example, a material for forming an electrode) or an insulating material (for example, a material for forming an insulating layer) is selected as the first functional material, and as the second functional material, It is preferable to select a semiconductor material.

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

Example 1
1. Fabrication of Thin Film Transistor (1) Formation of Gate Electrode A gate electrode was formed on the highly transparent and smooth PEN film Teonex Q65HA (thickness 125 μm) by Teijin DuPont Films by reverse printing. The printing ink for the gate electrode is made of conductive ink (manufactured by Dainippon Ink & Chemicals, Inc. (DIC Corporation): EPODIC RAGT-19; containing nano silver particles as a conductive material (electrode material)), and from polydimethylsiloxane. The blanket surface was coated with the same ink with a dry film thickness equivalent to 150 nm, the non-image area was removed with a relief plate, and then the ink was transferred from the blanket to the PEN film surface with some ink solvent remaining. Next, a gate electrode was formed by performing a heat treatment at 180 ° C. for 30 minutes.

(2) Formation of gate insulating film An organic insulating material (trade name: Chemite CT-4112 (polyimide resin)) from Kyocera Chemical Co., Ltd. is applied onto the gate electrode / PEN substrate by spin coating. And fired at 180 ° C. for 30 minutes to obtain a gate insulating film having a dry thickness of 600 nm.

(3) Formation of source / drain electrodes (formation of first functional material layer)
In this embodiment, the source / drain electrodes are used as the first functional material layer.
Considering the position of the gate electrode, source / drain electrodes were formed on the gate insulating film. The ink used was RAGT-19, as was the gate electrode. The ink solvent is an aqueous solvent mainly composed of water and ethanol. Thermal firing was performed at 180 ° C. for 30 minutes, as with the gate electrode. The electrode thickness is 150 nm.
The channel length of the source / drain electrodes was 20 μm and the channel width was 100 μm.

(4) Contact angle control process In tests 1 to 3, the following process is performed as a process for controlling the first functional material layer so that the contact angle of the second solvent is not substantially changed to a time-lapse drop. Executed. In Test 4 which is a comparison, execution of such a control process was omitted.
In Test 1, the substrate on which the source and drain electrodes were formed was washed by immersing in tetralin for 10 minutes, and then the cleaning solvent remaining on the source and drain electrodes was removed by heating at 100 ° C. for 1 minute. .
In Test 2, the control process was performed in the same manner as in Test 1 except that the immersion time in tetralin was 30 seconds.
In Test 3, the control process was carried out in the same manner as in Test 1 except that the solvent was changed from tetralin to chloroform and the immersion time in chloroform was 1 minute.
Tetralin and chloroform are good solvents for the following semiconductor material (second functional material), respectively.

(5) Print formation of semiconductor layer (formation of second functional material layer)
In this embodiment, the semiconductor layer is a second functional material layer.
After the above process was performed so that the contact angle variation did not change, a polymer organic semiconductor FS0085 of UK FLEXINK was dropped onto the channel so as to straddle the source / drain electrodes by ink jetting to form a coating film. The solvent of this ink is tetralin, and the solvent ratio is 98% or more. The inkjet droplet size was 40 pL, two droplets were applied onto the channel, and baked at 100 ° C. for 10 minutes to obtain a TFT. The average thickness of the obtained semiconductor layer on the channel was 700 nm.

2. Evaluation method (1) Confirmation of contact angle Separately from the base material provided for the above-mentioned "1- (5) Semiconductor layer printing", the above-mentioned "1- (4) contact angle control process" finished base material Was prepared, and the behavior with time of the contact angle of the second solvent (here, tetralin) of the second functional material ink applied on the first functional material layer (here, the source / drain electrodes) was confirmed.
Specifically, tetralin is applied onto the source / drain electrodes after the above “1- (4) contact angle control process”, and the contact angles immediately after the application and after 10 minutes are measured, and the amount of change is measured. If the absolute value is maintained at 10 ° or less, it can be determined that the control target by the control process has been achieved.
The results are shown in Table 1.

(2) Evaluation of TFT characteristics The obtained TFT was heat-treated at 100 ° C. for 10 minutes, and then Id-Vg characteristics were measured. From the measured data, carrier mobility, Vd30V, Vg-30V on Current variations and threshold voltage variations were determined.

  The results are shown in Table 1.

3. Evaluation The state in which the contact angle of tetralin (second solvent) to the source / drain electrode (first functional material layer) does not substantially change over time (the absolute value of the change amount after 10 minutes is 10). It can be seen that the surface conditions of the source / drain electrodes are homogenized in Tests 1 to 3, which are defined as “° or less”. In order to form the above state, it can be seen that a cleaning process with a solvent using a good solvent (here, tetralin or chloroform) of the second functional material is preferable. In Tests 1 to 3, it can be seen that the variation in TFT characteristics is remarkably suppressed as compared with Test 4 in which the second functional material ink is applied as it is after firing the source / drain electrodes.
Specifically, in tests 1 to 3, the on-current variation can be suppressed to 20% or less, and the coating shape on the channel of the semiconductor layer is stabilized by this process, leading to coating defects, insulating films, and electrodes. The repellency defects were also suppressed.
In tests 1 to 3, it can be seen that the variation in threshold voltage is also suppressed to 10% or less. This is considered to be a result of being able to obtain a uniform surface by immersing and washing with a good solvent of semiconductor ink. On the other hand, in Test 4, after the semiconductor ink is applied on the source / drain electrodes, the impurity components on the surface of the electrodes are redissolved in the solvent of the semiconductor ink, so that the carrier injectability varies or diffuses on the gate insulating film. Thus, it is considered that the dispersion of the threshold voltage is caused by the carrier causing trapping and the variation.

(Example 2)
1. Production of Thin Film Transistor (1) Formation to Source / Drain Electrode A base material on which the source / drain electrode was formed was prepared in the same manner as in Example 1.

(2) Output slope control process obtained by photoelectron yield spectroscopy measurement In Tests 5 to 7, the first functional material is used so that the output slope obtained by photoelectron yield spectroscopy measurement does not substantially change with time. As a process for controlling the layer (here, the source / drain electrodes), the following process was performed. In test 8 which is a comparison, execution of the control process was omitted.
In Test 5, the substrate on which the source and drain electrodes were formed was washed by immersing in a mixed solvent of pure water: isopropyl alcohol (abbreviation: IPA) = 1: 1 for 5 minutes, and then heated at 100 ° C. for 1 minute. Then, the cleaning solvent remaining on the source / drain electrodes was removed.
In Test 6, the control process was performed in the same manner as in Test 5 except that the immersion time in the mixed solvent of pure water: IPA = 1: 1 was set to 1 minute.
In Test 7, the control process was carried out in the same manner as in Test 5 except that the solvent was changed from pure water: IPA = 1: 1 to acetone and the immersion time in acetone was 1 minute.
Pure water, IPA, and acetone are good solvents for the electrode material (first functional material) of the source / drain electrodes, respectively.

(3) Print formation of semiconductor layer After performing the above process, a semiconductor layer (second functional material layer) was formed in the same manner as in Example 1. The second solvent is tetralin as in Example 1.

2. Evaluation Method (1) Confirmation of Output Gradient Obtained by Photoelectron Yield Spectrometry Separately from the above-mentioned “2- (2) Photoelectron Yield Spectroscopy” Prepare a base material that has completed the “control process of output tilt obtained by measurement”, and the first functional material layer (here source / drain electrodes) before and after the immersion treatment with the second solvent (here tetralin). Yield spectrometry was performed to confirm the time-dependent behavior of the output slope.
Specifically, the output gradient before applying tetralin on the source / drain electrodes after the above “2- (2) process for controlling the output gradient obtained by photoelectron yield spectroscopy measurement” and at the time when 10 minutes have elapsed from the application. If the absolute value of the change amount is maintained at 10% or less, it can be determined that the control target by the control process has been achieved. As photoelectron yield spectroscopy measurement, AC-2 of Riken Keiki Co., Ltd. was used, and the output slope when the detection light output was 100 nW was measured.

(2) Evaluation of TFT characteristics For the obtained TFT, carrier mobility, on-current variation of Vd30V, Vg-30V, and threshold voltage variation were obtained in the same manner as in Example 1.

  The results are shown in Table 2.

3. Evaluation When tetralin (second solvent) is immersed in the source / drain electrode (first functional material layer), the output slope obtained by photoelectron yield spectroscopy measurement of the source / drain electrode is substantially In Tests 5 to 7 in which no change occurs (the absolute value of the change amount after 10 minutes has passed is 10% or less), the on-current variation is 25% or less compared to Test 8 in which the process is not executed. It can be seen that variations in TFT characteristics can be suppressed at each stage. Furthermore, the carrier mobility is 0.1 (cm ² / V · sec) or more, which is larger than that of Example 1, and it can be seen that the electrical characteristics are further improved.
In order to form a state in which the output slope does not change substantially with time, a cleaning process using a good solvent (here, pure water, IPA, acetone) of the first functional material is suitable. I understand.

(Example 3)
1. Production of Thin Film Transistor (1) Formation to Source / Drain Electrode A base material on which the source / drain electrode was formed was prepared in the same manner as in Example 1.

(2) Control Process In Tests 9 to 11, (i) a process of controlling the first functional material layer so that the contact angle of the second solvent does not substantially change with time-lapse droplets, and (ii) ) The following process was performed as a process for controlling the first functional material layer so that the output slope obtained by photoelectron yield spectroscopy measurement would not change substantially with time. In the test 12 which is a comparison, the execution of the control process is omitted.
In Test 9, the base material on which the source and drain electrodes were formed was cleaned by immersing it in a mixed solvent of pure water: isopropyl alcohol = 1: 1 for 5 minutes, and then immersed in chloroform for 5 minutes for cleaning. The cleaning solvent remaining on the source / drain electrodes was removed by heating at 100 ° C. for 1 minute. Pure water and IPA are good solvents for the electrode material (first functional material) of the source / drain electrodes, respectively. Also,
In Test 10, the substrate on which the source and drain electrodes were formed was cleaned by immersing in acetone for 1 minute, then immersed in tetralin for 5 minutes, and then heated at 100 ° C. for 1 minute. The remaining cleaning solvent was removed.
In Test 11, the substrate on which the source and drain electrodes were formed was washed by immersing it in a mixed solvent of acetone: chloroform = 1: 1 for 5 minutes, and remained on the source / drain electrodes by heating at 100 ° C. for 1 minute. The cleaning solvent was removed.
Pure water, IPA, and acetone are good solvents for the electrode material (first functional material) of the source / drain electrodes, respectively. Tetralin and chloroform are good solvents for the semiconductor material (second functional material), respectively.

(3) Print formation of semiconductor layer After performing the above process, a semiconductor layer (second functional material layer) was formed in the same manner as in Example 1. The second solvent is tetralin as in Example 1.

2. Evaluation Method (1) Confirmation of Contact Angle The contact angle of the second solvent was confirmed in the same manner as in Example 1.

(2) Confirmation of output slope obtained by photoelectron yield spectroscopy As in Example 2, the output slope obtained by photoelectron yield spectroscopy was confirmed for the first functional material layer.

(3) Evaluation of TFT characteristics For the obtained TFT, the carrier mobility, the on-current variation of Vd30V, Vg-30V, and the threshold voltage variation were obtained in the same manner as in Example 1.
The results are shown in Table 3.

3. Evaluation (i) The process of controlling the first functional material layer so that the contact angle of the second solvent does not substantially change with time, and (ii) the output gradient obtained by photoelectron yield spectroscopy measurement However, in the tests 9 to 11 in which both of the processes for controlling the first functional material layer so as to be substantially unchanged with time are performed, compared to the test 12 in which the processes are not performed, It can be seen that TFT characteristics with low current variation and high carrier mobility can be obtained.
Further, in order to form a state in which the contact angle and the output slope do not substantially change with time, a good solvent (in this case, pure water, IPA, acetone) of the first functional material and a second function It turns out that the combined use of the good solvent (here tetralin, chloroform) of a material is suitable.

1: base material 2: first functional material layer 3: second solvent of second functional material ink 10: base material 11: gate electrode 12: insulator layer 13: source electrode 14: drain electrode 15: semiconductor layer

Claims (10)

The second solvent and the second function are formed on the first functional material layer formed by coating or printing the first functional material ink containing the first solvent and the first functional material on the substrate. In the method of laminating a functional material for forming a coating film by printing the second functional material ink containing the material,
A process of controlling the first functional material layer before forming the coating film of the second functional material ink;
In the process, when the second solvent of the second functional material ink is immersed in the first functional material layer, the contact angle of the second solvent with respect to the first functional material layer Is a process for controlling the first functional material layer so that the first functional material layer is not substantially changed over time.   The method for laminating functional materials according to claim 1, wherein the second functional material is an organic semiconductor material. The second solvent and the second function are formed on the first functional material layer formed by coating or printing the first functional material ink containing the first solvent and the first functional material on the substrate. In the method of laminating a functional material for forming a coating film by printing the second functional material ink containing the material,
The first functional material is a conductive material, and the second functional material is a semiconductor material;
A process of controlling the first functional material layer before forming the coating film of the second functional material ink;
In the process, when the second solvent of the second functional material ink is immersed in the first functional material layer, an output gradient obtained by photoelectron yield spectroscopy measurement of the first functional material layer is increased. A method of laminating a functional material, which is a process of controlling the first functional material layer so that it does not change substantially with time.   The functional material laminating method according to claim 1, wherein the first functional material ink is printed by an offset printing method.   The method for laminating functional materials according to claim 1, wherein the second functional material ink is printed by an inkjet method.   The process for controlling the first functional material layer includes a cleaning process using a solvent, a solution processing process including a third functional material, an annealing process using a solvent vapor, an ozone processing process, a plasma processing process, a CVD processing process, and a vapor deposition processing process. The method for laminating functional materials according to any one of claims 1 to 5, comprising any one or more of a sputtering treatment process and an active energy ray irradiation treatment process.   The process for controlling the first functional material layer includes a cleaning process using a solvent, and the solvent includes a good solvent for the first functional material. Method.   The process for controlling the first functional material layer includes a cleaning process using a solvent, and the solvent includes a good solvent for the second functional material. Method.   The process for controlling the first functional material layer includes a cleaning process using a solvent, and the solvent includes a good solvent for the first functional material and a good solvent for the second functional material. A method for laminating functional materials according to any one of the above. A functional material laminate obtained by the functional material lamination method according to claim 1.

Images