JP5729055B2 - Field effect transistor, display element, image display device, and system - Google Patents

Description

  The present invention relates to a field effect transistor, a display element, an image display device, and a system.

  A field effect transistor (FET) which is a kind of semiconductor device is a current flowing between a source and a drain by applying a gate voltage and inducing carriers in the semiconductor while an electric field is applied to a channel. This is a transistor capable of controlling.

Since FETs can be switched by applying a gate voltage, they are used as various switching elements and amplifying elements. Further, since the FET has a planar structure in addition to a low gate current, it can be easily manufactured as compared with a bipolar transistor, and further, high integration can be easily performed. For this reason, FETs are used in many of the integrated circuits used in current electronic devices.
Among them, the FET is applied to an active matrix type display as a thin film transistor (TFT).

  2. Description of the Related Art In recent years, liquid crystal displays (LCDs), organic EL (electroluminescence) displays (OLEDs), electronic papers, and the like have been put into practical use as flat thin displays (FPDs) of an active matrix system.

  These FPDs are usually driven by a driving circuit including a TFT using amorphous silicon or polycrystalline silicon as an active layer. In addition, FPDs are required to have larger size, higher definition, and higher speed driving performance. Accordingly, TFTs with higher carrier mobility, small change in characteristics over time, and small variation between elements are required. ing.

In recent years, an oxide semiconductor has attracted attention as a semiconductor material that can replace silicon. Among them, InGaZnO ₄ (a-IGZO) has features such as film formation at room temperature, amorphous state, and high mobility characteristics with a mobility of around 10 cm ² / V · s, and it has been actively developed for practical use. (See Non-Patent Document 1).

  An oxide semiconductor generates carriers due to oxygen vacancies, and is likely to deteriorate characteristics due to a change in oxygen concentration in a later process, or to deteriorate characteristics due to the influence of oxygen and moisture in the atmosphere. Therefore, it has been studied to protect the oxide semiconductor with a protective layer.

  On the other hand, in recent years, development of printable electronics using a wet process that can reduce the cost for vacuum processes that require expensive equipment such as sputtering, CVD (Chemical Vapor Deposition), and dry etching. Has become active.

As a method for forming a protective layer for protecting an oxide semiconductor, SiO ₂ and SiNx formed by a vacuum process are mainly used, but reports using printable electronics are increasing for the purpose of reducing the cost.

For example, a method using a silicon-based resin as a protective layer material has been proposed (see Patent Document 1). However, the silicon-based resin has a problem that the low hygroscopicity is not sufficient, and an oxide semiconductor protective layer made of a lower hygroscopic material is demanded.
In addition, a method of forming a protective layer of an oxide semiconductor by a coating method using a metal oxide thin film using polysilazane or alkoxysilane as a precursor, or polyimide or phenol resin has been proposed (see Patent Document 2). However, precursors such as polysilazane and alkoxysilane are materials that react with water in the atmosphere to cause a hydrolysis reaction, and have a problem that they are insufficient due to their low hygroscopicity. In addition, polyimide and phenolic resin are not sufficiently hygroscopic and have a problem that the carrier concentration of the oxide semiconductor is changed by an oxidation reaction by a baking process. The inventors have studied that there is a problem that a threshold voltage shift (depletion) of −5 V or more occurs when a metal oxide using alkoxysilane as a precursor or polyimide is used as a protective layer of an oxide semiconductor.

Therefore, a method has been proposed in which a fluororesin, which is a low moisture-absorbing material and is a stable material that does not easily oxidize, is used as a protective layer for an oxide semiconductor.
For example, a method has been proposed in which a shift in threshold value of TFT characteristics is suppressed by using a perfluorinated resin as a protective layer (see Patent Document 3).
Generally, since the fluororesin has a stable C—F bond with high binding energy, its surface exhibits liquid repellency. In particular, a perfluorinated resin in which all C—H groups are substituted with C—F groups exhibits high liquid repellency because the C—F groups are exposed on the surface at a higher density, and the contact angle with water is 100. More than °. Further, it is difficult to modify the surface of a perfluorinated resin due to its stability.
In the technique proposed above, since a fully fluorinated resin is used as a protective layer, surface modification becomes difficult even when a hydrophilic treatment such as UV ozone treatment or oxygen plasma treatment is performed. There is a problem that it is difficult to form a layer thereon. Further, even if a layer can be formed on the protective layer, there is a problem that the adhesion between the protective film and the layer is low and the reliability is poor.

  Therefore, in a field effect transistor using an oxide semiconductor, a field effect transistor that is low in cost, excellent in the coating property of an upper layer formed in a later step, and exhibits high reliability, and the field effect transistor At present, it is required to provide a display element, an image display device, and a system using the above.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention is a low-cost, field-effect transistor that is excellent in coatability of an upper layer formed in a later process and exhibits high reliability, and a display element and an image display using the field-effect transistor An object is to provide an apparatus and a system.

Means for solving the problems are as follows. That is,
<1> an insulating substrate;
A gate electrode formed on the insulating substrate;
A gate insulating layer formed on the gate electrode;
A source electrode and a drain electrode formed on the gate insulating layer;
An oxide semiconductor layer formed on the gate insulating layer and formed at least between the source electrode and the drain electrode;
A protective layer formed to cover the oxide semiconductor layer,
The protective layer contains a fluororesin;
The field effect transistor according to claim 1, wherein a contact angle of the protective layer with respect to water after forming the protective layer is 75 ° or more and 90 ° or less.
<2> The contact angle of the protective layer with respect to n-tetradecane is 0 ° or more and 50 ° or less, and the contact angle of the protective layer with respect to γ-butyrolactone is at least one of 0 ° or more and 40 ° or less. It is a field effect transistor.
<3> a light control element whose light output is controlled according to a drive signal;
A display element comprising the field effect transistor according to any one of <1> to <2>, and a drive circuit that drives the light control element.
<4> The display element according to <3>, wherein the light control element includes any one of an organic electroluminescence element and an electrochromic element.
<5> The display element according to <3>, wherein the light control element includes any one of a liquid crystal element, an electrophoretic element, and an electrowetting element.
<6> An image display device that displays an image according to image data,
A plurality of the display elements according to any one of <3> to <5> arranged in a matrix;
A plurality of wirings for individually applying a gate voltage to each field effect transistor in the plurality of display elements;
An image display device comprising: a display control device that individually controls a gate voltage of each of the field effect transistors through the plurality of wirings according to the image data.
<7> The image display device according to <6>,
An image data creation device that creates image data based on image information to be displayed and outputs the image data to the image display device.

  According to the present invention, the conventional problems can be solved, and the field effect transistor which is low in cost, excellent in the coating property of an upper layer formed in a subsequent process, and exhibits high reliability, and the electric field. A display element, an image display device, and a system using an effect transistor can be provided.

FIG. 1 is a diagram for explaining an image display apparatus. FIG. 2 is a diagram for explaining an example of the display element of the present invention. FIG. 3 is a diagram showing an example of the field effect transistor of the present invention. FIG. 4 is a schematic configuration diagram illustrating an example of an organic EL element. FIG. 5 is a schematic configuration diagram showing an example of the display element of the present invention. FIG. 6 is a schematic configuration diagram showing another example of the display element of the present invention. FIG. 7 is a schematic configuration diagram showing another example of the display element of the present invention. FIG. 8 is a diagram for explaining the display control apparatus. FIG. 9 is a diagram showing an example of a top contact / bottom gate type field effect transistor according to the present invention. FIG. 10 is a diagram for explaining a liquid crystal display. FIG. 11 is a diagram for explaining the display element in FIG. FIG. 12 is a diagram illustrating a change in contact angle of the protective layer with respect to water in Example 1 and Comparative Example 1 when UV ozone treatment is performed. FIG. 13 is a diagram showing a change in contact angle of the protective layer with respect to water in Example 1 and Comparative Example 1 when oxygen plasma treatment is performed. FIG. 14 is a diagram showing a change in contact angle of the protective layer with respect to n-tetradecane in Example 1 and Comparative Example 1 when UV ozone treatment is performed. FIG. 15 is a diagram showing a change in contact angle of the protective layer with respect to n-tetradecane in Example 1 and Comparative Example 1 when oxygen plasma treatment is performed. FIG. 16 is a diagram showing a change in contact angle with respect to γ-butyrolactone of the protective layer in Example 1 and Comparative Example 1 when UV ozone treatment is performed. FIG. 17 is a diagram showing a change in contact angle with respect to γ-butyrolactone of the protective layer in Example 1 and Comparative Example 1 when oxygen plasma treatment is performed. FIG. 18 is a graph showing an evaluation of the characteristics of the field effect transistor obtained in Example 2. FIG. 19 is a diagram evaluating the characteristics of the field-effect transistor obtained in Comparative Example 2. FIG. 20 is a diagram evaluating the characteristics of the field-effect transistor obtained in Comparative Example 3. FIG. 21 is a diagram illustrating the organic EL display device manufactured in Example 3.

(Field effect transistor)
The field effect transistor of the present invention has at least an insulating substrate, a gate electrode, a gate insulating layer, a source electrode, a drain electrode, an oxide semiconductor layer, and a protective layer, and further if necessary. And other members.

<Insulating substrate>
There is no restriction | limiting in particular as a shape, a structure, and a magnitude | size of the said insulating substrate, According to the objective, it can select suitably.
There is no restriction | limiting in particular as a material of the said insulating substrate, According to the objective, it can select suitably, For example, glass, a plastics etc. are mentioned.
There is no restriction | limiting in particular as said glass, According to the objective, it can select suitably, For example, an alkali free glass, silica glass, etc. are mentioned.
There is no restriction | limiting in particular as a material of the said plastics, According to the objective, it can select suitably, For example, a polycarbonate (PC), a polyimide (PI), a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN) etc. are mentioned. It is done.
The insulating substrate is preferably subjected to pretreatment such as cleaning with oxygen plasma, UV ozone, or UV irradiation in terms of surface cleaning and adhesion improvement.

<Gate electrode>
The gate electrode is not particularly limited as long as it is an electrode for applying a gate voltage, and can be appropriately selected according to the purpose.
The gate electrode is formed on the insulating substrate.
The material of the gate electrode is not particularly limited and may be appropriately selected depending on the purpose. For example, a metal or alloy such as Mo, Al, Ag, or Cu, a transparent conductive oxide such as ITO or ATO, Examples thereof include organic conductors such as polyethylene dioxythiophene (PEDOT) and polyaniline (PANI).

-Formation method of gate electrode-
The method for forming the gate electrode is not particularly limited and may be appropriately selected depending on the intended purpose. For example, (i) a method of patterning by photolithography after film formation by sputtering, dip coating, or the like ( ii) A method of directly forming a desired shape by a printing process such as inkjet, nanoimprint, or gravure.

  There is no restriction | limiting in particular as average thickness of the said gate electrode, Although it can select suitably according to the objective, 20 nm-1 micrometer are preferable and 50 nm-300 nm are more preferable.

<Gate insulation layer>
The gate insulating layer is formed on the gate electrode.
The material of the gate insulating layer is not particularly limited and can be appropriately selected according to the purpose. For example, a material already widely used for mass production such as SiO ₂ and SiN _x , La ₂ O ₃ , Examples thereof include high dielectric constant materials such as HfO ₂ and organic materials such as polyimide (PI) and fluorine-based resins.

-Formation method of gate insulating layer-
There is no restriction | limiting in particular as a formation method of the said gate insulating layer, According to the objective, it can select suitably, For example, vacuum film-forming methods, such as sputtering, chemical vapor deposition (CVD), and atomic layer deposition (ALD) , Printing methods such as spin coating, die coating, and inkjet.

  There is no restriction | limiting in particular as average thickness of the said gate insulating layer, Although it can select suitably according to the objective, 50 nm-3 micrometers are preferable, and 100 nm-1 micrometer are more preferable.

<Source electrode and drain electrode>
The source electrode and the drain electrode are not particularly limited as long as they are electrodes for taking out current, and can be appropriately selected according to the purpose.
The source electrode and the drain electrode are formed on the gate insulating layer.
There is no restriction | limiting in particular as a material of the said source electrode and the said drain electrode, According to the objective, it can select suitably, For example, the material same as the material described in description of the said gate electrode etc. are mentioned.

-Method for forming source electrode and drain electrode-
There is no restriction | limiting in particular as a formation method of the said source electrode and the said drain electrode, According to the objective, it can select suitably, For example, the same method as the formation method described in description of the said gate electrode is mentioned.

  There is no restriction | limiting in particular as average thickness of the said source electrode and the said drain electrode, Although it can select suitably according to the objective, 20 nm-1 micrometer are preferable and 50 nm-300 nm are more preferable.

<Oxide semiconductor layer>
The oxide semiconductor layer is formed on the gate insulating layer and is formed at least between the source electrode and the drain electrode.
The material of the oxide semiconductor layer is not particularly limited as long as it is an oxide semiconductor and can be appropriately selected according to the purpose. For example, In—Ga—Zn—O, I—Z—O, In An oxide semiconductor such as -Mg-O can be given.

-Formation method of oxide semiconductor layer-
There is no restriction | limiting in particular as a formation method of the said oxide semiconductor layer, According to the objective, it can select suitably, For example, a sputtering method, a pulse laser deposition (PLD) method, CVD method, ALD (Atomic Layer Deposition) After film formation by a vacuum process such as dip coating, solution process such as dip coating, spin coating, die coating, etc., a desired shape is directly formed by a printing method such as patterning by photolithography, inkjet, nanoimprinting, gravure, etc. The method etc. are mentioned.

  There is no restriction | limiting in particular as average thickness of the said oxide semiconductor layer, Although it can select suitably according to the objective, 5 nm-1 micrometer are preferable and 10 nm-0.5 micrometer are more preferable.

<Protective layer>
The said protective layer is formed so that the said oxide semiconductor layer may be coat | covered, contains a fluororesin, and also contains another component as needed.
When the protective layer contains the fluororesin, the field effect transistor can suppress a Vth shift in TFT characteristics.

The protective layer has a contact angle of 75 ° or more and 90 ° or less with respect to water of the protective layer after the formation of the protective layer.
The contact angle can be measured by, for example, using an automatic contact angle measuring device (OCA20, manufactured by Eiko Seiki Co., Ltd.), attaching 1 μL of a contact angle measurement target droplet on the protective layer, and measuring 9 seconds after the adhesion.
The contact angle of the protective layer with respect to water after the protective layer is formed is within 24 hours after the curing treatment when the fluororesin contained in the protective layer is a thermosetting fluororesin or a UV curable fluororesin. If the fluororesin is a thermoplastic resin, it means the contact angle measured within 24 hours after the heat treatment for volatilizing the solvent, etc. It is a contact angle in the state which is not going.
Usually, a fluororesin having a contact angle of more than 90 °, for example, a fully fluorinated resin in which all C—H bonds in the resin are replaced with C—F bonds, is used as an oxide semiconductor protective layer. It has a function of suppressing the Vth shift of characteristics. On the other hand, the coating property of the layer formed on the protective layer in the subsequent step is inferior and the adhesiveness is insufficient. In addition, the fluororesin having a contact angle of less than 75 ° has good coating properties on the protective layer, but is insufficient from the viewpoint of suppressing the Vth shift of TFT characteristics.
In the present invention, the contact angle with respect to water of the protective layer after the formation of the protective layer is set to 75 ° or more and 90 ° or less, thereby suppressing the Vth shift of the TFT characteristics and the layer formed on the protective layer. Application properties (printability) of (for example, an anode, a cathode, and a partition wall in an organic EL display device as a display element) are excellent, and high adhesion can be obtained.

There is no restriction | limiting in particular as a method which makes the contact angle with respect to the water of the said protective layer 75 degrees or more and 90 degrees or less, According to the objective, it can select suitably, For example, as a fluororesin, a hydroxyl group, a carboxyl group, a sulfone group For example, a method using a fluororesin having a hydrophilic functional group, a method using a fluororesin having an ether bond, a method using a fluororesin having an ester bond, a method using a partially fluorinated resin as the fluororesin, and the like. Among these, it is preferable to use a partially fluorinated resin having at least one of a hydrophilic functional group, an ether bond, and an ester bond as the fluororesin.
Here, the partially fluorinated resin is a fluororesin in which a part of C—H bonds are substituted with C—F bonds.

Moreover, the contact angle with respect to water can be made small by hydrophilizing the protective layer.
There is no restriction | limiting in particular as said hydrophilic treatment, According to the objective, it can select suitably, For example, UV ozone treatment, oxygen ozone treatment, argon plasma treatment, corona treatment etc. are mentioned. Among these, UV ozone treatment and oxygen plasma treatment are preferable.
The fluororesin is made of a fluororesin having a low density of C—F groups exposed on the surface as compared with a fluororesin having a high liquid repellency with a contact angle with water exceeding 90 °, such as a perfluorinated resin. Thus, the functional group on the surface can be decomposed by the hydrophilization treatment to generate a hydrophilic functional group, and the contact angle with water can be reduced.
In the case of a fully fluorinated resin having a contact angle with respect to water exceeding 90 °, the contact angle is hardly changed even when a hydrophilic treatment is performed.
That is, the surface free energy can be increased by hydrophilization treatment by containing a fluororesin as the protective layer and further having a contact angle of the protective layer of 75 ° or more and 90 ° or less after the formation of the protective layer. It is possible to improve the adhesion between the protective layer and the upper layer of the protective layer.

  The contact angle of the protective layer after the hydrophilic treatment is a contact angle measured within 24 hours after the hydrophilic treatment.

The contact angle of the protective layer with respect to water after the hydrophilization treatment is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of increasing the adhesion between the protective layer and the protective layer upper layer. 0 ° to 55 ° is preferable, 0 ° to 20 ° is more preferable, and 0 ° to 5 ° is particularly preferable. However, in the case of patterning the protective film upper layer by a printing method such as inkjet, it is not limited thereto, and both the adhesion between the protective layer and the protective layer upper layer, and the patterning properties of the protective layer upper layer Thus, the contact angle of the protective layer with respect to water can be selected as appropriate.
Here, the contact angle of the protective layer after the hydrophilic treatment is a contact angle measured within 24 hours after the hydrophilic treatment.
In addition, the lower limit value of 0 ° of the contact angle indicates a state where the droplet spreads in a thin film form before measurement is impossible.

The protective layer preferably has a contact angle with respect to n-tetradecane of 0 ° to 50 ° and a contact angle with respect to γ-butyrolactone of at least 0 ° to 40 °.
In the display element in this embodiment to be described later, examples of the layer formed on the protective layer include an insulating layer (partition wall, interlayer insulating film, etc.) formed of a resin such as polyimide or acrylic, nanometal ink, or the like. A conductive layer (a cathode or an anode of an organic EL element, a pixel electrode such as a liquid crystal element or an electrophoretic element), and the like. The protective film is γ-butyrolactone, a polar solvent often used as a solvent for a coating solution of a resin such as polyimide or acrylic, or n-tetradecane, a nonpolar solvent often used as a solvent for a nanometal ink. By satisfy | filling the said contact angle, it is excellent in the applicability | paintability (printability) of the said protective film upper layer, and can obtain high adhesiveness.

  The fluororesin may be a thermoplastic resin, a thermosetting resin, or a UV curable resin. Among these, thermosetting resins and UV curable resins are preferable. When the thermosetting resin or the UV curable resin is used, a cured product is obtained by crosslinking between molecules by heat treatment or UV irradiation, whereby high mechanical strength can be obtained and high reliability can be obtained. This is advantageous.

There is no restriction | limiting in particular as glass transition temperature (Tg) of the said fluororesin, Although it can select suitably according to the objective, 150 degreeC or more is preferable and 200 degreeC or more is more preferable. When the Tg is less than 150 ° C., a malfunction due to a phenomenon such as softening may occur in a subsequent process.
The glass transition temperature (Tg) can be measured, for example, by differential scanning calorimetry (DSC).

The electrical insulating property of the protective layer is not particularly limited and may be appropriately selected depending on the intended purpose. However, the volume resistivity is preferably 1 × 10 ¹⁰ Ω · cm or more, and 1 × 10 ¹² Ω · cm. The above is more preferable.
The volume resistivity can be measured by, for example, a two-terminal method.

  The protective layer may have a single layer structure or a multilayer structure. Since the fluororesin can prevent deterioration of characteristics of the oxide semiconductor and maintain high reliability, the protective layer may be a single layer structure. Moreover, if it is a single layer structure, the said field effect transistor can be manufactured at lower cost.

-Method for forming protective layer-
There is no restriction | limiting in particular as a formation method of the said protective layer, According to the objective, it can select suitably, For example, it can form by apply | coating the coating liquid containing the material which forms the said protective layer.

  The application method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include spin coating, ink jet printing, slit coating, nozzle printing, gravure printing, and dip coating. These coating methods may be used to directly form a desired shape, or the coating solution may be prepared as a photosensitive material and patterned by photolithography to form a desired shape.

After the application, heat treatment may be performed as necessary.
There is no restriction | limiting in particular as temperature of the said heat processing, Although it can select suitably according to the objective, 150 to 300 degreeC is preferable.
There is no restriction | limiting in particular as time of the said heat processing, Although it can select suitably according to the objective, 5 minutes-10 hours are preferable.

  There is no restriction | limiting in particular as average thickness of the said protective layer, Although it can select suitably according to the objective, 0.05 micrometers-20 micrometers are preferable, and 0.1 micrometer-10 micrometers are more preferable.

The field-effect transistor can have high reliability by suppressing the change in carrier concentration due to an oxidation reaction of the oxide semiconductor layer by including the protective layer. In addition, since the protective layer can be formed by a coating method, a field effect transistor can be manufactured at low cost.
Further, the protective layer has a small contact angle, and the contact angle can be easily reduced by UV ozone treatment, oxygen plasma treatment, etc., and it becomes easy to produce the upper layer by coating or printing. It can be suitably applied to the production of display elements by printing (printable electronics). Specifically, it is possible to form an electrode (anode, cathode) in an organic EL element by printing conductive particle-containing ink such as nanoparticulate ITO ink or Ag ink on the protective layer by inkjet. Become.

  The structure of the field effect transistor is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a top contact / bottom gate type and a bottom contact / bottom gate type.

  The field effect transistor can be suitably used for a display element to be described later, but is not limited thereto, and can be used for an IC card, an ID tag, and the like, for example.

(Display element)
The display element of the present invention includes at least a light control element and a drive circuit that drives the light control element, and further includes other members as necessary.

<Light control element>
The light control element is not particularly limited as long as it is an element that controls the light output in accordance with a drive signal, and can be appropriately selected according to the purpose. For example, an organic electroluminescence (EL) element, an electrochromic element Examples include (EC) elements, liquid crystal elements, electrophoretic elements, electrowetting elements, and the like.

<Drive circuit>
The drive circuit is not particularly limited as long as it has the field effect transistor of the present invention, and can be appropriately selected according to the purpose.

<Other members>
There is no restriction | limiting in particular as said other member, According to the objective, it can select suitably.

  Since the display element includes the field effect transistor of the present invention, it is possible to extend the life and cost.

(Image display device)
The image display device of the present invention includes at least a plurality of display elements, a plurality of wirings, and a display control device, and further includes other members as necessary.

<Display element>
The display element is not particularly limited as long as it is the display element of the present invention arranged in a matrix, and can be appropriately selected according to the purpose.

<Wiring>
The wiring is not particularly limited and can be appropriately selected depending on the purpose as long as a gate voltage and an image data signal can be individually applied to each field effect transistor in the display element.

<Display control device>
The display control device is not particularly limited as long as the gate voltage and the signal voltage of each field effect transistor can be individually controlled via the plurality of wirings according to image data. It can be selected appropriately.

<Other members>
There is no restriction | limiting in particular as said other member, According to the objective, it can select suitably.

Since the image display device includes the display element of the present invention, it is possible to extend the life and cost.
The image display device is used as display means in portable information devices such as mobile phones, portable music playback devices, portable video playback devices, electronic BOOK and PDA (Personal Digital Assistant), and imaging devices such as still cameras and video cameras. be able to. It can also be used as a display means for various information in a mobile system such as a car, an aircraft, a train, and a ship. Furthermore, various information display means in a measurement device, an analysis device, a medical device, and an advertising medium can be used.

(system)
The system of the present invention includes at least the image display device of the present invention and an image data creation device.
The image data creation device creates image data based on image information to be displayed, and outputs the image data to the image display device.

Hereinafter, a display element, an image display device, and a system of the present invention will be described with reference to the drawings.
First, a television apparatus as an example of the system of the present invention will be described.
A television device as an example of the system of the present invention can employ, for example, the configurations described in paragraphs [0038] to [0058] and FIG. 1 of JP 2010-074148.

Next, the image display apparatus of the present invention will be described.
As the image display device of the present invention, for example, the configurations described in paragraphs [0059] to [0060], FIG. 2 and FIG. 3 of JP 2010-074148 A can be employed.

Next, the display element of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a display 310 in which display elements are arranged on a matrix. As shown in FIG. 1, the display 310 includes n scanning lines (X0, X1, X2, X3,..., Xn-2, Xn-1) arranged at equal intervals along the X-axis direction. ) And m data lines (Y0, Y1, Y2, Y3,..., Ym-1) arranged at equal intervals along the Y-axis direction, and arranged at equal intervals along the Y-axis direction. M current supply lines (Y0i, Y1i, Y2i, Y3i,..., Ym-1i).
Therefore, the display element can be specified by the scanning line and the data line.

FIG. 2 is a schematic configuration diagram showing an example of the display element of the present invention.
As an example, the display element includes an organic EL (electroluminescence) element 350 and a drive circuit 320 for causing the organic EL element 350 to emit light, as shown in FIG. That is, the display 310 is a so-called active matrix organic EL display. The display 310 is a color-compatible 32-inch display. The size is not limited to this.

The drive circuit 320 in FIG. 2 will be described.
The drive circuit 320 includes two field effect transistors 11 and 12 and a capacitor 13.
The field effect transistor 11 operates as a switch element. The gate electrode G is connected to a predetermined scanning line, and the source electrode S is connected to a predetermined data line. The drain electrode D is connected to one terminal of the capacitor 13.

  The capacitor 13 is for storing the state of the field effect transistor 11, that is, data. The other terminal of the capacitor 13 is connected to a predetermined current supply line.

  The field effect transistor 12 is for supplying a large current to the organic EL element 350. The gate electrode G is connected to the drain electrode D of the field effect transistor 11. The drain electrode D is connected to the anode of the organic EL element 350, and the source electrode S is connected to a predetermined current supply line.

  Therefore, when the field effect transistor 11 is turned on, the organic EL element 350 is driven by the field effect transistor 12.

As shown in FIG. 3 as an example, the field effect transistors 11 and 12 include a substrate 21, a gate electrode 22, a gate insulating layer 23, a source electrode 24, a drain electrode 25, an oxide semiconductor layer 26, and a protective layer 27. Have.
The field effect transistors 11 and 12 can be formed by the materials, processes, and the like described in the description of the field effect transistor of the present invention.

  Here, each field effect transistor is a so-called “bottom contact / bottom gate type”, but may be a “top contact / bottom gate type”.

FIG. 4 is a schematic configuration diagram illustrating an example of an organic EL element.
In FIG. 4, the organic EL element 350 includes a cathode 312, an anode 314, and an organic EL thin film layer 340.

  The material of the cathode 312 is not particularly limited and may be appropriately selected depending on the purpose. For example, aluminum (Al), magnesium (Mg) -silver (Ag) alloy, aluminum (Al) -lithium (Li) An alloy, ITO (Indium Tin Oxide), etc. are mentioned. A magnesium (Mg) -silver (Ag) alloy becomes a high reflectance electrode if it is sufficiently thick, and a semitransparent electrode if it is an extremely thin film (less than about 20 nm). Although light is extracted from the anode side in FIG. 4, light can be extracted from the cathode side by using a transparent or semi-transparent electrode for the cathode.

  There is no restriction | limiting in particular as a material of the anode 314, According to the objective, it can select suitably, For example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), a silver (Ag) -neodymium (Nd) alloy, Etc. In addition, when a silver alloy is used, it becomes a high reflectance electrode and is suitable when taking out light from the cathode side.

  The organic EL thin film layer 340 includes an electron transport layer 342, a light emitting layer 344, and a hole transport layer 346. The electron transport layer 342 is connected to the cathode 312, and the hole transport layer 346 is connected to the anode 314. When a predetermined voltage is applied between the anode 314 and the cathode 312, the light emitting layer 344 emits light.

  Here, the electron transport layer 342 and the light emitting layer 344 may form one layer, an electron injection layer may be provided between the electron transport layer 342 and the cathode 312, and hole transport is further performed. A hole injection layer may be provided between the layer 346 and the anode 314.

  Further, the case of so-called “bottom emission” in which light is extracted from the substrate side has been described, but “top emission” in which light is extracted from the side opposite to the substrate may be used.

  FIG. 5 shows an example of a display element in which the organic EL element 350 and the drive circuit 320 are combined.

The display element includes a substrate 31, first and second gate electrodes 32 and 33, a gate insulating layer 34, first and second source electrodes 35 and 36, first and second drain electrodes 37 and 38, first The second oxide semiconductor layers 39 and 40, the first and second protective layers 41 and 42, the interlayer insulating film 43, the organic EL layer 44, and the cathode 45 are included. The first drain electrode 37 and the second gate electrode 33 are connected via a through hole formed in the gate insulating layer 34.
In FIG. 5, for the sake of convenience, it appears that a capacitor is formed between the second gate electrode 33 and the second drain electrode 38. However, in practice, the location where the capacitor is formed is not limited, and a capacitor having a necessary capacity is appropriately selected. Can be designed where needed.
Further, in the display element of FIG. 5, the second drain electrode 38 functions as an organic EL element 350 anode.
Substrate 31, first and second gate electrodes 32 and 33, gate insulating layer 34, first and second source electrodes 35 and 36, first and second drain electrodes 37 and 38, first and second electrodes The oxide semiconductor layers 39 and 40 and the first and second protective layers 41 and 42 can be formed by materials, processes, and the like described in the description of the field effect transistor of the present invention.

  After the formation of the first and second protective layers 41 and 42, it is preferable to perform surface modification treatment such as UV ozone treatment or oxygen plasma treatment. As a result, the adhesion between the first and second protective layers 41 and 42 and the interlayer insulating film 43 can be improved.

  There is no restriction | limiting in particular as a material of the interlayer insulation film 43 (planarization film | membrane), According to the objective, it can select suitably, For example, resin, such as a polyimide and an acryl, photosensitive resin using them, SOG, etc. (Spin on glass). The process for forming the interlayer insulating film is not particularly limited and can be appropriately selected according to the purpose. For example, a desired process can be performed by spin coating, inkjet printing, slit coating, nozzle printing, gravure printing, dip coating, or the like. The shape may be directly formed, or may be patterned by a photolithography method if it is a photosensitive material.

  There is no restriction | limiting in particular as a preparation method of the organic EL layer 44 and the cathode 45, According to the objective, it can select suitably, For example, vacuum film-forming methods, such as a vacuum evaporation method and a sputtering method, an inkjet, nozzle coating, etc. Solution process.

  Thus, a display element which is a so-called “bottom emission” organic EL element that extracts light emission from the substrate side can be manufactured. In this case, the substrate 31, the gate insulating film 34, and the second drain electrode (anode) 38 are required to be transparent.

Further, as shown in FIG. 6, by forming the interlayer insulating film 43 using the materials and processes of the first and second protective layers 41 and 42 in FIG. 5, the interlayer insulating film 43 functions as a protective layer. It is possible to shorten the process by providing
In this case, it is preferable to perform surface modification treatment such as UV ozone treatment or oxygen plasma treatment after the formation of the interlayer insulating film 43 (the protective layer in the present invention). As a result, the adhesion between the interlayer insulating film 43 and the counter electrode 45 can be improved.

5 and 6, the configuration in which the organic EL element 350 is disposed beside the drive circuit 320 has been described. However, as illustrated in FIG. 7, the configuration in which the organic EL element 350 is disposed above the drive circuit 320. It is good. Also in this case, so-called “bottom emission” in which light emission is extracted from the substrate side is required, and the drive circuit 320 is required to be transparent. The source / drain electrodes and anode are made of transparent conductive materials such as ITO, In ₂ O ₃ , SnO ₂ , ZnO, ZnO added with Ga, ZnO added with Al, and SnO ₂ added with Sb. It is preferable to use an oxide.

  As an example, the display control device 400 includes an image data processing circuit 402, a scanning line driving circuit 404, and a data line driving circuit 406, as shown in FIG.

  The image data processing circuit 402 determines the luminance of the plurality of display elements 302 in the display 310 based on the output signal of the video output circuit.

  The scanning line driving circuit 404 individually applies voltages to the n scanning lines in accordance with an instruction from the image data processing circuit 402.

  The data line driving circuit 406 individually applies voltages to the m data lines in accordance with an instruction from the image data processing circuit 402.

  In the above embodiment, the case where the organic EL thin film layer is composed of an electron transport layer, a light emitting layer, and a hole transport layer has been described, but the present invention is not limited to this. For example, the electron transport layer and the light emitting layer may be a single layer. An electron injection layer may be provided between the electron transport layer and the cathode. Furthermore, a hole injection layer may be provided between the hole transport layer and the anode.

  In the above-described embodiment, the case of so-called “bottom emission” in which light emission is extracted from the substrate side has been described. However, the present invention is not limited to this. For example, a substrate using a high reflectance electrode such as silver (Ag) -neodymium (Nd) alloy as the anode 314 and a translucent electrode such as magnesium (Mg) -silver (Ag) alloy or a transparent electrode such as ITO as the cathode 312. You may take out light from the opposite side.

  In the above embodiment, the field effect transistor is a so-called “bottom contact / bottom gate type”, but the present invention is not limited to this. For example, as shown in FIG. 9, a so-called “top contact / bottom gate type” may be used. The top contact / bottom gate type field effect transistor shown in FIG. 9 includes a substrate 21, a gate electrode 22, a gate insulating layer 23, a source electrode 24, a drain electrode 25, an oxide semiconductor layer 26, And a protective layer 27.

  Moreover, although the said embodiment demonstrated the case where a light control element was an organic EL element, it is not limited to this, For example, a light control element may be an electrochromic element. In this case, the display 310 is an electrochromic display.

  The light control element may be a liquid crystal element. In this case, the display 310 is a liquid crystal display. As an example, as shown in FIG. 10, a current supply line for the display element 302 ′ is unnecessary.

  In this case, as shown in FIG. 11 as an example, the drive circuit 320 ′ is composed of one field effect transistor 14 and a capacitor 15 similar to the field effect transistors (11, 12) described above. Can do. In the field effect transistor 14, the gate electrode G is connected to a predetermined scanning line, and the source electrode S is connected to a predetermined data line. Further, the drain electrode D is connected to the pixel electrode of the liquid crystal element 370 and the capacitor 15. Note that reference numerals 16 and 372 in FIG. 11 denote counter electrodes (common electrodes) of the liquid crystal element 370.

  In the embodiment, the light control element may be an electrophoretic element. The light control element may be an electrowetting element.

  Moreover, although the said embodiment demonstrated the case where a display respond | corresponds to a color, it is not limited to this.

  Note that the field-effect transistor according to this embodiment can be used for other than display elements (for example, IC cards and ID tags).

  Since the field effect transistor of the present invention is low in cost and high in reliability, the same effect can be obtained for a display element, an image display device, and a system using the field effect transistor.

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

(Example 1 and Comparative Example 1)
<Preparation of samples for wettability and adhesion evaluation>
In order to evaluate the wettability and adhesion of the protective layer of the field effect transistor, an evaluation sample was prepared.
-Preparation of evaluation sample of Example 1-
A fluororesin coating film was prepared on a glass substrate by applying heat treatment at 230 ° C. for 1 hour after spin coating using a partially fluorinated resin having a hydrophilic functional group. Next, the produced fluororesin coating film was subjected to hydrophilic treatment by UV ozone treatment or oxygen plasma treatment. As an apparatus for UV ozone treatment, UV-300 manufactured by samco was used. The UV lamp is a water-cooled low-pressure mercury lamp having a main wavelength of 254 nm and 185 nm, heated at 90 ° C., and subjected to UV ozone treatment for 0 to 20 minutes to produce a sample for evaluation on which a protective layer was formed. On the other hand, as an oxygen plasma processing apparatus, PDC-510 manufactured by Yamato Scientific Co., Ltd. was used, the oxygen flow rate was 50 sccm, the power was 500 W, and the treatment was performed for 0 second to 60 seconds to produce an evaluation sample on which a protective layer was formed.

-Preparation of sample for evaluation of Comparative Example 1-
In the preparation of the above evaluation sample, the same procedure as in the above preparation of the evaluation sample was performed except that the partially fluorinated resin having a hydrophilic functional group was replaced with Cytop (Asahi Glass Co., Ltd., CTL-809A, fully fluorinated resin). Thus, a sample for evaluation was produced.

<Evaluation>
-Evaluation of wettability-
The contact angle of the sample for evaluation produced above was measured. The measurement was performed using an automatic contact angle measuring apparatus (OCA20 manufactured by Eiko Seiki Co., Ltd.) with 1 μL of a contact angle measurement target droplet attached on the fluororesin coating film and 9 seconds after the attachment. Water (pure water), n-tetradecane, and γ-butyrolactone were used for the contact angle measurement target liquid.
The results of using water (pure water) as the contact angle measurement target liquid are shown in FIGS. The results of using n-tetradecane as the contact angle measurement target liquid are shown in FIGS. The results of using γ-butyrolactone as the contact angle measurement target liquid are shown in FIGS. 16 and 17.
12 and 13, the fluororesin coating film in Comparative Example 1 showed high liquid repellency with a contact angle with water of 100 ° or more in an untreated state. Further, even when the UV ozone treatment was performed, no contact angle change occurred, and even when the oxygen plasma treatment was performed, the contact angle of 90 ° or more was maintained. On the other hand, the fluororesin in Example 1 has a water contact angle of 90 ° or less in an untreated state (before hydrophilization treatment), which is lower in liquid repellency than Comparative Example 1, and UV ozone treatment and oxygen A wettability with a contact angle of 5 ° or less was obtained regardless of which hydrophilic treatment of the plasma treatment was performed.
14 and 15, in Comparative Example 1, it was difficult to make the contact angle with respect to n-tetradecane smaller than 50 ° even when the hydrophilic treatment was performed. The contact angle was 5 ° or less regardless of whether or not the treatment was performed.
16 and 17, in Comparative Example 1, it was difficult to make the contact angle with respect to γ-butyrolactone smaller than 40 ° even when the hydrophilization treatment was performed, whereas in Example 1, the hydrophilization was performed. The contact angle showed 5 degrees or less irrespective of the presence or absence of a process.
From these results, in Comparative Example 1, it was difficult to reduce the contact angle even after the hydrophilization treatment, whereas in Example 1, water, n-tetradecane, and γ-butyrolactone In any case, the contact angle is small, the wettability of the surface is good, and the adhesion with a layer (for example, a partition wall, an anode, a cathode, etc.) formed in a later process can be made good. I found out.

-Evaluation of applicability-
With respect to the fluororesin coating films prepared in Example 1 and Comparative Example 1, samples without hydrophilization treatment, UV ozone treatment for 10 minutes, and oxygen plasma treatment for 60 seconds were produced. For each sample, spin coating application experiment using polyimide resin (Toray Industries, DL-1000, solvent: mixed solvent containing γ-butyrolactone), and nano Ag ink (Harima Kasei Co., NPS-J) , Solvent: n-Tetradecane) was used to conduct line pattern formation experiments by inkjet. The results are shown in Table 1.

In Table 1, UV ozone treatment was performed at 90 ° C. for 10 minutes. The oxygen plasma treatment was performed at 500 W for 60 seconds under an oxygen flow rate of 50 sccm.

In Comparative Example 1, in the case of no hydrophilization treatment and UV ozone treatment, the polyimide resin did not adhere at all even when the polyimide resin was spin-coated, and application was impossible. When nano-Ag ink was ink-jetted, the droplets adhering onto the fluororesin coating film were finely separated, and discontinuous lines were formed. In the case of the oxygen plasma treatment, when polyimide resin was spin-coated, the polyimide resin adhered to a part of the fluororesin coating film, but a non-uniform film was formed. When inkjetting nano Ag ink, discontinuous lines were formed as in the case of no hydrophilization treatment and UV ozone treatment.
On the other hand, in Example 1, in any case of no hydrophilization treatment, UV ozone treatment, and oxygen plasma treatment, the polyimide resin spin coating can be applied uniformly, and the nano Ag ink inkjet is uniform. A continuous line was formed.

From the above, the fluororesin coating film having a contact angle with water of 81 ° and a contact angle with respect to n-tetradecane and γ-butyrolactone of 5 ° or less without hydrophilization was prepared on the fluororesin coating film. It was found that a uniform entire surface coating film can be formed by spin coating using a polyimide resin, and that continuous and uniform line formation by ink jet using nano Ag ink can be performed.
In addition, the fluororesin coating film produced in Example 1 has a contact angle with water of 5 ° or less by both hydrophilic treatment of UV ozone treatment and oxygen plasma treatment, and increases the surface free energy. It is possible to improve the adhesion with the coating film formed on the film.
On the other hand, the highly liquid-repellent fluororesin coating film produced in Comparative Example 1 sufficiently generates hydrophilic groups on the surface by both the UV ozone treatment and the oxygen plasma treatment due to its high liquid repellency. The contact angle for water exceeds 90 °, the contact angle for n-tetradecane exceeds 50 °, the contact angle for γ-butyrolactone exceeds 40 °, and is uniform on the fluororesin coating film. It turned out that it was difficult to form a coating film.

(Example 2)
<Fabrication of field effect transistor>
A bottom contact / bottom gate type field effect transistor as shown in FIG. 3 was fabricated.
-Formation of gate electrode-
First, the gate electrode 22 was formed on the glass substrate 21. Specifically, an ITO (Indium Tin Oxide) film, which is a transparent conductive film, was formed on the glass substrate 21 by DC sputtering so as to have an average thickness of about 100 nm. Thereafter, a photoresist was applied, and a resist pattern similar to the pattern of the gate electrode 22 to be formed was formed by pre-baking, exposure by an exposure apparatus, and development. Further, the ITO film in the region where the resist pattern is not formed is removed by reactive ion etching (RIE), and then the resist pattern is also removed, thereby forming the gate electrode 22 made of ITO. .

-Formation of gate insulation layer-
Next, a gate insulating layer 23 was formed on the gate electrode 22. Specifically, an SiO ₂ film was formed on the gate electrode 22 and the glass substrate 21 by RF sputtering so as to have an average thickness of about 300 nm, and the gate insulating layer 23 was formed.

-Formation of source and drain electrodes-
Next, a source electrode 24 and a drain electrode 25 were formed on the gate insulating layer 23. Specifically, an ITO film, which is a transparent conductive film, is formed on the gate insulating layer 23 by DC sputtering so that the average thickness is about 100 nm. Thereafter, a photoresist is applied on the ITO film, A resist pattern similar to the pattern of the source electrode 24 and the drain electrode 25 to be formed was formed by pre-baking, exposure by an exposure apparatus, and development. Further, the ITO film in the region where the resist pattern is not formed is removed by RIE, and then the resist pattern is also removed, thereby forming the source electrode 24 and the drain electrode 25 made of the ITO film.

-Formation of oxide semiconductor layer-
Next, an oxide semiconductor layer 26 was formed. Specifically, an Mg—In-based oxide (In ₂ MgO ₄ ) film is formed by DC sputtering so as to have an average thickness of about 100 nm, and thereafter, a photocatalyst is formed on the Mg-In-based oxide film. A resist was applied, and a resist pattern similar to the pattern of the oxide semiconductor layer 26 to be formed was formed by pre-baking, exposure with an exposure apparatus, and development. Furthermore, the oxide semiconductor layer 26 was formed by removing the Mg—In-based oxide film in the region where the resist pattern was not formed by RIE, and then removing the resist pattern. Thus, the oxide semiconductor layer 26 was formed so that a channel was formed between the source electrode 24 and the drain electrode 25.

-Formation of protective layer-
Next, the protective layer 27 was formed. Specifically, using a partially fluorinated resin having the same hydrophilic functional group as used in Example 1, it was applied by spin coating, pre-baked at 60 ° C. for 2 minutes, and then post-baked at 230 ° C. for 60 minutes. A protective layer 27 was formed so as to cover the oxide semiconductor layer 26 by baking. The average thickness of the protective layer thus formed was about 1.5 μm.

(Comparative Example 2)
<Fabrication of field effect transistor>
First, a gate electrode, a gate insulating layer, a source electrode and a drain electrode, and an oxide semiconductor layer were formed over a glass substrate by a method similar to that in Example 2.
-Formation of protective layer-
Next, a protective layer was formed. Specifically, using Cytop (Asahi Glass Co., Ltd., CTL-809A, fully fluorinated resin), it is applied by spin coating, pre-baked at 90 ° C for 30 minutes, and post-baked at 230 ° C for 60 minutes. Thus, a protective layer was formed so as to cover the oxide semiconductor layer. The average thickness of the protective layer thus formed was about 1.5 μm.

(Comparative Example 3)
<Fabrication of field effect transistor>
First, a gate electrode, a gate insulating layer, a source electrode and a drain electrode, and an oxide semiconductor layer were formed over a glass substrate by a method similar to that in Example 2.
-Formation of protective layer-
Next, a protective layer was formed. Specifically, using a polyimide resin (DL-1000 manufactured by Toray Industries, Inc.) by spin coating, pre-baking at 120 ° C. for 2 minutes, and then post-baking at 230 ° C. for 30 minutes, the oxidation is performed. A protective layer was formed so as to cover the physical semiconductor layer. The average thickness of the protective layer thus formed was about 1.5 μm.

<Evaluation of transistor characteristics>
The characteristics (Vds = 20 V) of the field effect transistors manufactured in Example 2, Comparative Example 2, and Comparative Example 3 were measured. Note that the measurement was performed immediately after the production of the field effect transistor. The results are shown in FIG. 18 (Field Effect Transistor of Example 2), FIG. 19 (Field Effect Transistor of Comparative Example 2), and FIG. 20 (Field Effect Transistor of Comparative Example 3).
From FIG. 20, when polyimide was used as a protective layer for the oxide semiconductor, a change in depletion was observed. The amount of change in Vth was about -7V.
On the other hand, from FIG. 18 and FIG. 19, when the fluororesin was used as the protective layer for the oxide semiconductor, the characteristic change was hardly observed, and the Vth change amount remained at about −1V.
The reason for this is that the fluororesin is less hygroscopic than the polyimide resin, and the polyimide resin is more likely to be oxidized by heat treatment than the stable fluororesin, reducing the oxide semiconductor. Therefore, it is considered that a phenomenon called depletion occurred due to an increase in carrier concentration.
In Comparative Example 3, the contact angle of the polyimide resin used as the protective layer with respect to water was measured by the same method as in Example 1 and found to be 73 °.
Further, the field effect transistors manufactured in Example 2 and Comparative Example 2 have no change in mobility even after being stored in the atmosphere for 300 hours, and the amount of change in Vth is within 1 V. It was found that the film functions equivalently.

  From Examples 1-2 and Comparative Examples 1-3, the field effect transistor of the present invention using a protective layer containing a fluororesin and having a contact angle with water after forming the protective layer of 75 ° or more and 90 ° or less, In addition to showing high reliability due to the stability of the C—F bond, it was found that the upper layer of the protective layer can be easily formed and the adhesion between the protective layer and the upper layer of the protective layer can be improved.

(Example 3)
<Production of organic EL display device>
An organic EL display device as shown in FIG. 21 was produced.
-Formation of gate electrode-
First, the first gate electrode 52 and the second gate electrode 53 were formed on the glass substrate 51. Specifically, an ITO film, which is a transparent conductive film, was formed on the glass substrate 51 by DC sputtering so as to have an average thickness of about 100 nm. Thereafter, a photoresist was applied, and a resist pattern similar to the pattern of the first gate electrode 52 and the second gate electrode 53 to be formed was formed by pre-baking, exposure by an exposure apparatus, and development. Further, the ITO film in the region where the resist pattern was not formed was removed by RIE. Then, the first gate electrode 52 and the second gate electrode 53 were formed by removing the resist pattern.

-Formation of gate insulation layer-
Next, the gate insulating layer 54 was formed. Specifically, an SiO ₂ film was formed on the first gate electrode 52, the second gate electrode 53, and the glass substrate 51 by RF sputtering so as to have an average thickness of about 300 nm. Thereafter, a photoresist was applied, and a resist pattern similar to the pattern of the formed gate insulating layer 54 was formed by pre-baking, exposure by an exposure apparatus, and development. Furthermore, the SiO ₂ film in the region where the resist pattern was not formed was removed by RIE, and then the resist pattern was also removed to form the gate insulating layer 54.

-Formation of source and drain electrodes-
Next, a first source electrode 55 and a second source electrode 56, and a first drain electrode 57 and a second drain electrode 58 were formed. Specifically, an ITO film, which is a transparent conductive film, is formed on the gate insulating layer 54 by DC sputtering so that the average thickness is about 100 nm, and then a photoresist is applied on the ITO film, A resist pattern similar to the pattern of the first source electrode 55 and the second source electrode 56 to be formed, and the first drain electrode 57 and the second drain electrode 58 is formed by pre-baking, exposure by an exposure apparatus, and development. did. Further, the ITO film in the region where the resist pattern was not formed was removed by RIE. Thereafter, the resist pattern was also removed to form a first source electrode 55 and a second source electrode 56 made of an ITO film, and a first drain electrode 57 and a second drain electrode 58.

-Formation of oxide semiconductor layer-
Next, the first oxide semiconductor layer 59 and the second oxide semiconductor layer 60 were formed. Specifically, an Mg—In-based oxide (In ₂ MgO ₄ ) film is formed by DC sputtering so as to have an average thickness of about 100 nm, and thereafter, a photocatalyst is formed on the Mg-In-based oxide film. A resist was applied, and a resist pattern similar to the pattern of the first oxide semiconductor layer 59 and the second oxide semiconductor layer 60 to be formed was formed by pre-baking, exposure using an exposure apparatus, and development. Further, the Mg—In-based oxide film in the region where the resist pattern was not formed was removed by RIE. Thereafter, the first oxide semiconductor layer 59 and the second oxide semiconductor layer 60 were formed by removing the resist pattern. Thus, the first oxide semiconductor layer 59 was formed so that a channel was formed between the first source electrode 55 and the first drain electrode 56. Further, the second oxide semiconductor layer 60 was formed so that a channel was formed between the second source electrode 57 and the second drain electrode 58.

-Formation of protective layer-
Next, the protective layer 61 was formed. Specifically, by using a partially fluorinated resin (photosensitive resin) having the same hydrophilic functional group as that used in Example 1, it is applied by spin coating, prebaked, exposed by an exposure apparatus, and developed to be desired. After obtaining the above pattern, post-baking is performed at 230 ° C. for 60 minutes, so that the protective layer 61 having a through hole on the second drain electrode 58 is formed on the first oxide semiconductor layer 59 and the second oxide semiconductor layer 59. The oxide semiconductor layer 60 was formed so as to be covered. The average thickness of the protective layer 61 thus formed was about 1.5 μm.

-Formation of partition walls-
Next, the surface of the protective layer was modified by UV ozone treatment, and then the partition wall 62 was formed. Specifically, using a positive photosensitive polyimide resin (DL-1000, manufactured by Toray Industries, Inc.), a desired pattern is obtained by spin coating on the protective layer 61, pre-baking, exposure with an exposure apparatus, and development. After that, the partition wall 62 was formed by post-baking at 230 ° C. for 30 minutes.

-Formation of anode-
Next, after the surface modification of the protective layer 61 was performed again by UV ozone treatment, the anode 63 was formed. Specifically, an anode 63 having an average thickness of about 50 nm was formed on the protective layer 61 by ink jetting using nano-particle ITO ink.

-Formation of organic EL layer-
Next, an organic EL layer 64 was formed on the anode 63 by an ink jet apparatus using a polymer organic light emitting material.

-Formation of cathode-
Next, the cathode 65 was formed. Specifically, the cathode 65 was formed on the organic EL layer 64 and the partition wall 62 by vacuum deposition of MgAg.

-Formation of sealing layer-
Next, the sealing layer 66 was formed. Specifically, a sealing layer 66 was formed on the cathode 65 by depositing a SiO ₂ film with an average thickness of about 2 μm by CVD.

-Lamination-
Next, bonding with the counter substrate 68 was performed. Specifically, an adhesive layer 67 was formed on the sealing layer 66, and a counter substrate 68 made of a glass substrate was bonded thereto. Thus, a display panel of the real organic EL display device having the configuration shown in FIG. 21 was produced.

-Drive circuit connection-
Next, the drive circuit was connected. Specifically, a drive circuit (not shown) is connected to the display panel so that an image can be displayed on the display panel. This produced the image display system of the organic EL display device.

This organic EL display device is a so-called “bottom emission” type organic EL display device because a field effect transistor is formed of a transparent film in all layers and only a cathode uses a metal layer having high reflectivity. .
In this organic EL display device, it was easy to form the partition wall 62 and the anode 63 by coating on the protective layer 61 also serving as an interlayer insulating film, and showed high adhesion. This organic EL display device has high reliability and can be manufactured at low cost. Moreover, in this organic EL display device, the protective layer and the partition showed good adhesion. The protective layer and the anode also showed good adhesion.

  The field effect transistor of the present invention can be suitably used for an active matrix type flat thin display and the like because it is low in cost, excellent in the coating property of an upper layer formed in a subsequent process, and exhibits high reliability.

DESCRIPTION OF SYMBOLS 11 Field effect transistor 12 Field effect transistor 13 Capacitor 14 Field effect transistor 15 Capacitor 16 Counter electrode 21 Base material 22 Gate electrode 23 Gate insulating layer 24 Source electrode 25 Drain electrode 26 Oxide semiconductor layer 27 Protective layer 31 Substrate 32 Second One gate electrode 33 Second gate electrode 34 Gate insulating layer 35 First source electrode 36 Second source electrode 37 First drain electrode 38 Second drain electrode 39 First oxide semiconductor layer 40 Second Oxide semiconductor layer 41 First protective layer 42 Second protective layer 43 Interlayer insulating film 44 Organic EL layer 45 Cathode 51 Glass substrate 52 First gate electrode 53 Second gate electrode 54 Gate insulating layer 55 First source Electrode 56 First drain electrode 57 Second source electrode 58 Second Drain electrode 59 First oxide semiconductor layer 60 Second oxide semiconductor layer 61 Protective layer 62 Partition wall 63 Anode 64 Organic EL layer 65 Cathode 66 Sealing layer 67 Adhesive layer 68 Counter substrate 302, 302 ′ Display element 310 Display 312 Cathode 314 Anode 320, 320 ′ Drive circuit (drive circuit)
340 Organic EL thin film layer 342 Electron transport layer 344 Light emitting layer 346 Hole transport layer 350 Organic EL element 370 Liquid crystal element 372 Counter electrode 400 Display control device 402 Image data processing circuit 404 Scan line drive circuit 406 Data line drive circuit

JP 2007-0773705 A JP 2010-103203 A JP 2007-299913 A Japanese Patent No. 3801271

K. Nomura, et al., “Room-temperament fabrication of transparent flexible thin-film transformers using amorphous semiconductors”, NATURE, VOL4. 25, NOVEMBER, 2004, p. 488-492

Claims (8)

An insulating substrate;
A gate electrode formed on the insulating substrate;
A gate insulating layer formed on the gate electrode;
A source electrode and a drain electrode formed on the gate insulating layer;
An oxide semiconductor layer formed on the gate insulating layer and formed at least between the source electrode and the drain electrode;
A protective layer formed to cover the oxide semiconductor layer,
The protective layer contains a fluororesin;
Contact angle with water of the protective layer after the protective layer formation state, and are 75 ° to 90 °,
The field effect type wherein the contact angle of the protective layer with respect to n-tetradecane is 0 ° or more and 50 ° or less and the contact angle of the protective layer with γ-butyrolactone is at least 0 ° or more and 40 ° or less. Transistor. The field effect transistor according to claim 1, wherein a contact angle of the protective layer with respect to water after forming the protective layer is 81 ° or more and 90 ° or less. A light control element whose light output is controlled according to a drive signal;
A display element comprising the field effect transistor according to claim 1 and a drive circuit for driving the light control element. The display element according to claim 3, wherein the drive circuit includes a planarizing film formed on the field effect transistor. The light control element is an organic electroluminescence element or electrochromic element.
The display element according to claim 3, which has any one of them. The display element according to claim 3, wherein the light control element includes any one of a liquid crystal element, an electrophoretic element, and an electrowetting element. An image display device that displays an image according to image data,
A plurality of display elements according to any one of claims 3 to 6 arranged in a matrix;
A gate voltage is individually applied to each field effect transistor in the plurality of display elements.
Multiple wires for,
In accordance with the image data, the gate voltage of each field effect transistor is set to the plurality of arrangements.
An image display device comprising: a display control device that individually controls via lines. An image display device according to claim 7,
Image data is created based on image information to be displayed, and the image data is stored in the image display device.
And a system for generating image data to be output.