JP2014107280A - Thin film transistor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film transistor which has high reliability and a manufacturing method thereof.SOLUTION: A thin film transistor comprises: a substrate; a gate electrode formed on the substrate; a gate insulation film formed on the substrate so as to cover the gate electrode; a semiconductor layer formed on the gate insulation film on the gate electrode; a protection film formed so as to cover a part of the semiconductor layer to divide the semiconductor layer into two exposed regions; and a source electrode and a drain electrode which are formed so as to cover the semiconductor layer and parts of the protection film. The thin film transistor further comprises a resist layer between the protection film and the source electrode and/or between the protection film and the drain electrode.

Description

  The present invention relates to a thin film transistor using an oxide semiconductor and a manufacturing method thereof.

At present, thin film transistors, particularly field effect transistors, are widely used as semiconductor memory integrated circuits, high frequency signal amplifying elements, and the like.
In addition, as a switching element of a flat and thin image display device (FPD) such as a liquid crystal display device (LCD), an electroluminescence display device (EL), and a field emission display (FED), a thin film transistor among field effect transistors (Hereinafter also referred to as TFT) is used. In a TFT used for FPD, an amorphous silicon thin film or a polycrystalline silicon thin film is formed as an active layer on a glass substrate.

A TFT using the above-described amorphous silicon thin film or polycrystalline silicon thin film as an active layer requires a relatively high temperature thermal process. For this reason, although a glass substrate can be used, it is difficult to use a resin substrate having low heat resistance.
Further, the FPD is required to be thinner, lighter, and more resistant to breakage, and the use of a lightweight and flexible resin substrate instead of the glass substrate is also being studied. For this reason, TFTs using an amorphous oxide that can be formed at a low temperature, such as an In—Ga—Zn—O-based oxide, are being actively developed.

A TFT using an oxide has a substrate, a gate electrode, a gate insulating film, an active layer composed of an oxide semiconductor, a source electrode, and a drain electrode. The source electrode and the drain electrode are formed on the active layer. ing.
In a TFT using an oxide, a source electrode and a drain electrode are formed by etching a conductive film. For this reason, if an etching stopper layer for protecting the active layer is not formed on the active layer, the active layer may also be etched when the source electrode and the drain electrode are formed, resulting in poor TFT characteristics and uneven characteristics. is there. In an extreme case, the active layer is entirely etched and may not exhibit TFT characteristics. For this reason, a TFT provided with an etching stopper layer for protecting the active layer has been proposed.

  Patent Document 1 discloses a substrate, a gate electrode, a gate insulating film, an active layer formed of an InGaZnO oxide semiconductor, and a protective layer having a function of protecting the active layer from etching (an etching stopper layer, a source electrode, and a drain electrode). It is what you have.

  The protective film of the thin film transistor corresponding to the channel protective film of Patent Document 1 is formed by first forming a layer serving as a protective film over the entire surface (FIG. 4A of Patent Document 1) and then applying a resist on the layer serving as the protective film. A film (second resist 51) is formed and patterned into a protective film shape. Then, after patterning the protective film by etching using oxalic acid or the like using this resist film as a mask, the resist film is peeled off (FIG. 4B of Patent Document 1). In this way, a protective film is formed on the semiconductor layer.

  Here, the resist film made of an organic material remaining on the protective film after patterning the protective film is removed. As a method for removing the resist that is no longer necessary, the resist film is immersed in a mixed solution of concentrated sulfuric acid and hydrogen peroxide solution. A method or a method using oxygen plasma (ashing) is used. In the case of a wet process using a mixed solution of concentrated sulfuric acid and hydrogen peroxide solution, there is a problem that the resist removal capability tends to decrease with a change in the composition of the mixed solution, and it is difficult to form a fine wiring pattern in the wet process. Therefore, the resist removal method is generally etching using oxygen plasma.

However, when removing the resist using oxygen plasma, the surface of the semiconductor layer that is not covered by the protective film that becomes the connection between the semiconductor layer and the source / drain electrodes is damaged by the oxygen plasma, and the reliability of the TFT is low. There was a problem of becoming. Actually, when the connection portion between the semiconductor layer and the source / drain electrodes becomes defective due to surface damage caused by oxygen plasma during resist removal, the Vd-Id characteristics show saturation characteristics at high Vg as shown in FIG. Therefore, the ON current reaches its peak, and the reliability is lowered. For example, in FIG. 4B of Patent Document 1, the resist film on the protective film is removed after patterning the protective film (channel portion etching stopper 53). In the etching process for removing the resist film, oxidation is performed. The surface of the physical semiconductor layer will deteriorate.
In addition, when the connection part of a semiconductor layer and a source / drain electrode is favorable, a Vd-Id characteristic shows a linear characteristic like FIG. 5 in high Vg.

JP 2007-157916 A

  An object of the present invention is to solve the above-mentioned problems based on the prior art and provide a highly reliable thin film transistor and a method for manufacturing the same.

  A first invention made to solve the above problems includes a substrate, a gate electrode formed on the substrate, a gate insulating film formed on the substrate so as to cover the gate electrode, A semiconductor layer formed on the gate electrode on the gate insulating film; a protective film formed so as to cover a part of the semiconductor layer so as to be divided into two exposed regions; and the semiconductor layer and the protective film A thin film transistor having a source electrode and a drain electrode formed so as to cover a part, wherein a resist layer is provided between the protective film and the source electrode and / or between the protective layer and the drain electrode. The thin film transistor is characterized by having a thin film transistor.

  A second invention made to solve the above problems is a thin film transistor in which at least a gate electrode, a gate insulating film, a semiconductor layer, a protective film covering a front semiconductor layer, a source electrode, and a drain electrode are formed on a substrate. And forming the gate electrode on the substrate, forming the gate insulating film on the substrate so as to cover the gate electrode, and forming the semiconductor layer on the gate insulating film. Forming a protective film on the semiconductor layer, forming a first resist film on the protective film, and using the first resist film as a mask Etching a layer to be a protective film to form a protective film; the gate insulating layer; the protective film; an exposed portion of the semiconductor layer not covered with the protective film; and the first over the protective film Forming a film to be a source electrode and a drain electrode so as to cover the resist film; forming a second resist film on the film to be a source electrode and a drain electrode; and masking the second resist film And etching the layer to be the source electrode and the drain electrode to form the source electrode and the drain electrode, and removing the first resist film and the second resist film by etching. A method of manufacturing a thin film transistor characterized by the above.

  According to the present invention, the source / drain electrodes are formed before the resist film for forming the protective film pattern is removed, so that the source / drain electrodes are formed after the resist film for forming the protective film pattern is removed. As compared with the above, it is possible to provide a thin film transistor and a method for manufacturing the same, in which damage on the surface of the semiconductor layer in contact with the source / drain electrodes is reduced.

1 is a schematic cross-sectional view illustrating a structure of a thin film transistor in an embodiment of the present invention. 1 is a schematic cross-sectional view showing a manufacturing process of a thin film transistor in an embodiment of the present invention. (Top) and plan view (bottom). 1 is a schematic cross-sectional view showing a manufacturing process of a thin film transistor in an embodiment of the present invention. (Top) and plan view (bottom). The graph which shows the Vd-Id characteristic of a thin-film transistor when the connection part of a semiconductor layer and a source / drain electrode is bad. The graph which shows the Vd-Id characteristic of a thin-film transistor when the connection part of a semiconductor layer and a source / drain electrode is favorable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in the embodiments, the same components are denoted by the same reference numerals, and redundant description among the embodiments is omitted.

As shown in FIG. 1, a thin film transistor according to an embodiment of the present invention includes a gate electrode 2, a gate insulating layer 4 formed on the gate electrode so as to cover the gate electrode, and a gate insulating layer. This is a bottom-gate / top-contact thin film transistor including an upper semiconductor layer 5 and a source electrode 7 and a drain electrode 8 connected to the semiconductor layer. A protective film 6 is formed on the semiconductor layer so as to divide the semiconductor layer into two regions, and the source electrode and the drain electrode are in contact with each other in the divided semiconductor layer region and are electrically connected. The drain electrode is connected to the pixel electrode 11 so as to cover a part of the protective film 6. A capacitor electrode 3 is formed under the drain electrode with the gate insulating layer interposed therebetween. Further, the source electrode and the drain electrode cover a part of the first resist film 9.
2 and 3 are a schematic plan view (lower view) and a schematic cross-sectional view (upper view) taken along line II ′ of the plan view in the manufacturing process of the thin film transistor shown in FIG.

  Hereafter, each component of this invention is demonstrated in detail along a manufacturing process.

  As the substrate 1 according to the embodiment of the present invention, specifically, polymethyl methacrylate, polyacrylate, polycarbonate, polystyrene, polyethylene sulfide, polyethersulfone, polyolefin, polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymer, poly Ether sulfone, polyvinyl fluoride film, ethylene-tetrafluoroethylene copolymer resin, weather resistant polypropylene, glass fiber reinforced acrylic resin film, glass fiber reinforced polycarbonate, transparent polyimide, fluorine resin, cyclic polyolefin resin, glass, quartz, etc. However, the present invention is not limited to these. These may be used as a single substantially transparent substrate 1, but can also be used as a composite substantially transparent substrate 1 in which two or more kinds are laminated.

When the substantially transparent substrate 1 according to the embodiment of the present invention is an organic film, a transparent gas barrier layer (not shown) is formed to improve the durability of the element on the active matrix substrate. Can do. Examples of the gas barrier layer include aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), and diamond-like carbon (DLC). The present invention is not limited to these. These gas barrier layers can also be used by laminating two or more layers. The gas barrier layer may be formed only on one side of the substantially transparent substrate 1 using an organic film, or may be formed on both sides. The gas barrier layer can be formed using a vacuum deposition method, an ion plating method, a sputtering method, a laser ablation method, a plasma CVD (Chemical Vapor Deposition) method, a hot wire CVD method, a sol-gel method, and the like. It is not limited.

  First, a gate electrode and a capacitor electrode and respective wirings are formed on a substrate. The electrode portion and the wiring portion do not need to be clearly separated, and in the present invention, the constituent elements of each thin film transistor are particularly called electrodes. When there is no need to distinguish between the electrode and the wiring, they are collectively described as a gate, a source, a drain, a capacitor, and the like.

FIG. 2A is a schematic plan view at the stage where the gate and the capacitor are formed, and a schematic cross-sectional view taken along I-I ′ of the plan view. In FIG. 2A, the source electrode and the source wiring, and the capacitor electrode and the capacitor wiring are formed in an integrated stripe shape. Therefore, an array of thin film transistors can be arranged on the gate and capacitor lines.

For each electrode (gate electrode, source electrode, drain electrode, capacitor electrode, pixel electrode) and each wiring according to the embodiment of the present invention, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), cadmium oxide (CdO), indium cadmium oxide (CdIn ₂ O ₄ ), cadmium tin oxide (Cd ₂ SnO ₄ ), zinc tin oxide (Zn ₂ SnO ₄ ), indium zinc oxide (In—Zn—O) An oxide material such as Moreover, what doped this oxide material with the impurity is used suitably. For example, indium oxide doped with tin (Sn), molybdenum (Mo), titanium (Ti), tin oxide doped with antimony (Sb) or fluorine (F), zinc oxide indium, aluminum, gallium ( For example, doped with Ga). Among these, indium tin oxide (commonly known as ITO) in which tin (Sn) is doped in indium oxide is particularly preferably used because of high transparency and low resistivity. In addition, the conductive oxide material and gold (Au), silver (Ag), copper (Cu), cobalt (Co), tantalum (Ta), molybdenum (Mo), chromium (Cr), aluminum (Al), nickel ( A laminate of a plurality of thin films of metals such as Ni), tungsten (W), platinum (Pt), and titanium (Ti) can also be used. In this case, a three-layer structure in which a conductive oxide thin film / metal thin film / conductive oxide thin film is laminated in order in order to prevent oxidation or deterioration with time of the metal material is particularly preferably used.
In addition, it is preferable to make the metal thin film layer as thin as possible so that light reflection and light absorption at the metal thin film layer do not disturb the visibility of the display device. Specifically, it is desirably 1 nm or more and 20 nm or less.

Further, when transparency is not required, a light-shielding metal may be used, or the metal may be formed thick enough to become opaque. Specifically, the above-mentioned gold (Au), silver (Ag), copper (Cu), cobalt (Co), tantalum (Ta), molybdenum (Mo), chromium (Cr), aluminum (Al), nickel (Ni) Further, metals such as tungsten (W), platinum (Pt), and titanium (Ti) can be used, and a non-light-transmitting material may be used only for some of the electrodes and wirings. For example, when the gate electrode and the source wiring are formed in a region other than the display region, such as a black matrix region, the light-shielding metal material can be used.

  The gate, capacitor, source, drain, and pixel electrode may be made of the same material, or may be made of different materials. However, in order to reduce the number of processes, it is more desirable that the gate and the capacitor, and the source and the drain are made of the same material. These wirings and electrodes can be formed by vacuum deposition, ion plating, sputtering, laser ablation, plasma CVD, photo CVD, hot wire CVD or screen printing, letterpress printing, ink jet printing, etc. However, it is not limited to these, and a publicly known general method can be used. Patterning can be performed, for example, by forming a protective film on a pattern forming portion using a photolithography method and removing an unnecessary portion by etching. However, this is not limited to this method, and a known general patterning method is used. Can be used.

Next, an insulating layer 4 is formed so as to cover the gate electrode. It can be formed on the entire surface of the substrate. The material used for the gate insulating film 4 according to the embodiment of the present invention is not particularly limited, but silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, tantalum oxide, yttrium oxide, hafnium oxide, hafnium aluminate, Examples include inorganic materials such as zirconia oxide and titanium oxide, or polyacrylates such as PMMA (polymethyl methacrylate), PVA (polyvinyl alcohol), PS (polystyrene), transparent polyimide, polyester, epoxy, polyvinylphenol, and polyvinyl alcohol. However, it is not limited to these. In order to suppress the gate leakage current, the resistivity of the insulating material is desirably 10 ¹¹ Ωcm or more, more preferably 10 ¹⁴ Ωcm or more. The gate insulating film 4 may be formed by a vacuum deposition method, an ion plating method, a sputtering method, a laser ablation method, a dry film forming method such as a plasma CVD, a photo CVD method, a hot wire CVD method, a spin coating method, a dip coating method, a screen. A wet film forming method such as a printing method is appropriately used depending on the material. These gate insulating films 4 may be used as a single layer or may be used by stacking two or more layers. Further, the composition may be inclined in the growth direction.

Next, as shown in FIG. 2B, the semiconductor layer 5 is formed at a position directly above the gate electrode 2 on the insulator layer 4.
As the semiconductor layer 5 according to the embodiment of the present invention, an oxide semiconductor material containing a metal oxide as a main component can be used. The oxide semiconductor material is zinc oxide (ZnO) which is an oxide containing one or more elements of zinc (Zn), indium (In), tin (Sn), tungsten (W), magnesium (Mg), and gallium. ), Indium oxide (InO), indium zinc oxide (In—Zn—O), tin oxide (SnO), tungsten oxide (WO), and zinc gallium indium oxide (In—Ga—Zn—O). It is done. The structure of these materials may be any of single crystal, polycrystal, microcrystal, mixed crystal of crystal and amorphous, nanocrystal scattered amorphous, and amorphous. In addition, when the semiconductor layer does not need transparency, other inorganic materials that can be used include silicon semiconductors such as hydrogenated amorphous silicon, microcrystalline silicon, polycrystalline silicon, and single crystal silicon. These materials are formed using a method such as a CVD method, a sputtering method, a pulse laser deposition method, a vacuum evaporation method, or a sol-gel method. Examples of CVD include hot wire CVD, plasma CVD, sputtering include RF magnetron sputtering, DC sputtering, and vacuum deposition include heat evaporation, electron beam evaporation, ion plating, and the like. It is not something. The film thickness of the semiconductor layer 5 is preferably 20 nm or more.

Next, as shown in FIG. 2C, a layer that becomes the protective film 6 is formed on the entire surface of the gate insulating layer 4 and the semiconductor layer 5.
The protective film 6 according to the embodiment of the present invention includes an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, tantalum oxide, yttrium oxide, hafnium oxide, hafnium aluminate, zirconia oxide, and titanium oxide. Or, polyacrylate such as PMMA (polymethyl methacrylate), PVA (polyvinyl alcohol), PS (polystyrene), transparent polyimide, polyester, epoxy, polyvinylphenol, polyvinyl alcohol, etc. can be used. Fluorinated resin in which hydrogen is replaced with fluorine, specifically, fluorinated epoxy, fluorinated acrylic, fluorinated polyimide, polyvinylidene fluoride, fluorinated olefin / propylene copolymer, fluorinated olefin / vinyl ether Polymers, fluorinated olefin / vinyl ester copolymers, fluorinated ether cyclized polymers, etc. can be used, but when an oxide semiconductor material is used as the semiconductor layer, an inorganic material should be selected as the protective film 6 Is desirable.

The protective film 6 preferably has a resistivity of 1 × 10 ¹¹ Ωcm or more, particularly 1 × 10 ¹⁴ Ωcm or more, so as not to electrically affect the semiconductor layer of the thin film transistor according to the present invention. If the protective film 6 is an inorganic material, a vacuum deposition method, an ion plating method, a sputtering method, a laser ablation method, a dry film forming method such as a plasma CVD, a photo CVD method, a hot wire CVD method, or a spin coating is used for an organic material. A wet film formation method such as a method, a dip coating method, or a screen printing method is appropriately used depending on the material. These protective films 6 may be used by stacking two or more layers.

Next, as shown in FIG. 2D, a first resist film 9 is formed in the shape of the protective film 6 by a photolithography process on the layer to be the protective film. As shown in FIG. 1, the protective film 6 covers the semiconductor layer 5 except for the contact portion between the source electrode 7 and the drain electrode 8, and the region where the protective film is formed has the semiconductor layer 5 in two regions. The first resist film 9 on the protective film 6 is also formed in the same shape as the protective film 6 because there is no particular limitation other than exposing a part so as to be divided.
Although the channel width is determined by the width of the semiconductor layer 6, since the source / drain electrodes are formed after the protective film 6 in the embodiment of the present invention, the channel length is determined by the width of the protective film 6.
Subsequently, as shown in FIG. 3A, the protective film 6 is etched and patterned using the first resist film 9 as a mask.

  For the first resist film 9 according to the embodiment of the present invention, a photosensitive acrylic resin, an epoxy resin, polyimide, a positive photoresist, or the like can be used, and the second resist film 10 described later has the same material. Can be used.

Next, as shown in FIG. 3B, the conductive material of the wiring / electrode material to be the source / drain electrode and the pixel electrode is applied to the entire surface of the substrate on the gate insulating layer 4, the semiconductor layer 5, and the first resist film 9. A film is formed and covered, including the protective film 6 and the first resist film 9.
By forming the source / drain electrodes before the removal of the first resist film 9 in this manner, the semiconductor layer 5 is compared with the case where the first resist film 9 is removed before the source / drain electrodes are formed. The damage on the surface of the contact portion with the source electrode 7 and the drain electrode 8 can be reduced.

Next, as shown in FIG. 3C, the source electrode and the drain electrode are electrically connected while covering the exposed surfaces of the two semiconductor layers 5, and the source electrode and the drain electrode are connected to the semiconductor layer 5. The conductive material layer is patterned so as to be connected only through the above. In the patterning process of the source / drain electrodes, a second resist film 10 having the same shape as the pattern of the source / drain electrodes is formed on the conductive material layer formed on the entire surface of the substrate, and the conductive material layer is etched using this as a mask. Is done.
The source / drain electrodes are preferably patterned so as to overlap the protective film 6 and the first resist film 9. As a result, the semiconductor layer 5 is covered with the source / drain electrodes and the protective film 6 when the second resist film described later is etched, so that the semiconductor layer 5 is not etched.

Usually, a protective film provided on the semiconductor layer of the thin film transistor serves as an etch stopper when patterning the source / drain electrodes. When the thin film transistor is used as an active matrix substrate having a pixel electrode, the pixel electrode and the drain electrode 8 are connected via a via formed in the interlayer insulating layer. At this time, the second resist film is formed on the drain electrode. If there is 10 residue, the reliability of the connection is lowered. Therefore, it is desirable to carefully remove the second resist film 10 described later. In the present invention, the first resist film 9 is formed on the protective film 6. Therefore, even if etching is performed until the second resist film is completely removed, the semiconductor layer 5 can be reliably prevented from being etched.
Further, it has been reported that when the semiconductor layer 5 and an organic insulating material such as a resist are in direct contact with each other, the driving of the transistor is hindered (for example, Japanese Patent Application Laid-Open No. 2007-299913). By providing the protective film 6, it is possible to prevent the semiconductor layer 5 from being deteriorated due to the first resist film 9, a resin such as epoxy, which constitutes an interlayer insulating layer described later, and the like contacting with the semiconductor layer 5. .

Next, as shown in FIG. 3D, a part of the first resist film 9 formed on the protective film 6 is removed together with the removal of the second resist film 10 formed on the source / drain electrodes. Is done.
As described above, since the step of removing the first resist film 9 on the protective film, which has been performed separately, is performed together with the step of removing the second resist film 10 on the source / drain electrodes, the first resist film 9 is removed. It is possible to improve the yield by reducing the number of steps for removing.

  Depending on the etching method and etching time, the first resist film 9 may not be completely removed and may remain partially in the semiconductor layer 5. In particular, since the source / drain electrodes are partially overlapped with the first resist film 9, there is a high possibility that the portion of the first resist film 9 where the source / drain electrodes overlap is left without being removed.

  When the thin film transistor of the present invention is used as an active matrix substrate used for driving a display or the like, an interlayer insulating layer for insulating the source electrode and the pixel electrode is formed on the substrate on which the source and drain electrodes are formed. The protective film 6 can protect the semiconductor layer 5 from the influence of various film forming / coating methods when forming the interlayer insulating layer.

  Examples of the material for the interlayer insulating layer include silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, tantalum oxide, yttrium oxide, hafnium oxide, hafnium aluminate, zirconia oxide, and titanium oxide, or PMMA (polyethylene oxide). Polyacrylate such as methyl methacrylate), PVA (polyvinyl alcohol), PS (polystyrene), transparent polyimide, polyester, epoxy, polyvinylphenol, polyvinyl alcohol, and the like can be used, but are not limited thereto.

In order to insulate between the source wiring and the pixel electrode, the interlayer insulating layer preferably has a resistivity of 1 × 10 ¹¹ Ωcm or more, particularly 1 × 10 ¹⁴ Ωcm or more. Interlayer insulation layers are vacuum deposition, ion plating, sputtering, laser ablation, plasma CVD, photo CVD, hot wire CVD, and other dry film formation methods, spin coating, dip coating, and screen printing. The wet film forming method such as the above is used as appropriate depending on the material. Two or more of these interlayer insulating layers may be stacked and used. Further, the composition may be inclined toward the growth direction.

  Subsequently, a through hole with the pixel electrode 11 is provided in the interlayer insulating layer, a conductive material is formed on the interlayer insulating layer so as to be connected to the drain electrode, and patterned into a predetermined pixel shape to form the second pixel electrode. By forming, an active matrix substrate can be obtained.

  By laminating the image display element and the counter electrode on the active matrix substrate thus created, an image display device can be obtained. Examples of the image display element include an electrophoretic display medium (electronic paper), a liquid crystal display medium, an organic EL, an inorganic EL, and the like. As a lamination method, the active matrix substrate of the present invention and a laminate of a counter substrate, a counter electrode, and an image display element are bonded together, a method of sequentially stacking an image display element, a counter electrode, and a counter substrate on a pixel electrode, etc. What is necessary is just to select suitably by the kind of image display element.

Note that the transistor of this embodiment can be used as an image display device using liquid crystal or an EL element, in particular, as an FPD switching element or driving element. Furthermore, the image display device using the transistor 10 of the present embodiment can be applied to a wide range of fields including a mobile phone display, a personal digital assistant (PDA), a computer display, an automobile information display, a TV monitor, or general lighting. is there.
Furthermore, the substrate of the transistor 10 of this embodiment can be a flexible substrate such as a plastic film, and can be applied to an IC card or an ID tag.

1 ... substrate 2 ... gate electrode (gate wiring)
3. Capacitor electrode (capacitor wiring)
4 ... Gate insulating film 5 ... Semiconductor layer 6 ... Protective film 7 ... Source electrode (source wiring)
8... Drain electrode 9... First resist film 10 .. second resist film 11 .. pixel electrode

Claims (2)

A substrate, a gate electrode formed on the substrate, a gate insulating film formed on the substrate so as to cover the gate electrode, and a semiconductor layer formed on the gate electrode on the gate insulating film; A protective film formed so as to cover a part of the semiconductor layer so as to be divided into two exposed regions; a source electrode and a drain electrode formed so as to cover a part of the semiconductor layer and the protective film; A thin film transistor comprising:
A thin film transistor comprising a resist layer between the protective film and the source electrode and / or between the protective layer and the drain electrode. A method of manufacturing a thin film transistor in which at least a gate electrode, a gate insulating film, a semiconductor layer, a protective film covering a front semiconductor layer, a source electrode, and a drain electrode are formed on a substrate,
Forming the gate electrode on the substrate;
Forming the gate insulating film on the substrate so as to cover the gate electrode, and forming the semiconductor layer on the gate insulating film;
Forming a layer to be a protective film on the semiconductor layer;
Forming a first resist film on the layer to be the protective film;
Etching the layer serving as the protective film using the first resist film as a mask to form a protective film;
A film to be a source electrode and a drain electrode is formed so as to cover the gate insulating layer, the protective film, the exposed portion of the semiconductor layer not covered with the protective film, and the first resist film on the protective film And a process of
Forming a second resist film on the film to be the source electrode and the drain electrode;
Etching the layer to be the source and drain electrodes by using the second resist film as a mask to form the source and drain electrodes;
Removing the first resist film and the second resist film by etching;
A method for producing a thin film transistor, comprising:

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