KR102302306B1 - A thin film transistor substrate having a passivation film, and a method of manufacturing the same - Google Patents

Abstract

[Problem] A thin film transistor substrate provided with a protective film, which can provide high driving stability, is provided.
[Solution] A thin film transistor substrate comprising a thin film transistor and a protective film made of a cured product of a photosensitive siloxane composition covering the thin film transistor, wherein the thin film transistor has a semiconductor layer made of an oxide semiconductor, and the photosensitive siloxane composition has an alkali dissolution rate It is a thin film transistor substrate characterized by containing at least two types of polysiloxane, a photosensitizer and a solvent which are different from each other.

Description

A thin film transistor substrate having a protective film and a method for manufacturing the same

The present invention relates to a thin film transistor substrate having a protective film and a method for manufacturing the same.

In recent years, development of thin film transistors using an oxide semiconductor typified by amorphous InGaZnO has been actively conducted for high-resolution displays. Compared with amorphous silicon thin film transistors used in liquid crystal displays, oxide semiconductors have high electron mobility and exhibit excellent electrical properties such as high on/off ratios, and thus are driving devices or power-saving types of organic EL displays. It is expected as a power device. In development for displays, it is an important task to maintain device operation stability as a transistor and uniformity on a large-area substrate in particular. As a very important factor for device operation stability, there is an insulating film that protects the oxide semiconductor layer from an external atmosphere. However, as such an insulating film, a protective insulating film used in conventional thin film transistors using amorphous silicon is mainly used (Patent Documents 1 and 2), and there is a concern that the physical properties inherent in the oxide semiconductor cannot be sufficiently utilized. And, this is considered to be one of the factors limiting the performance of the thin film transistor using the oxide semiconductor.

The protective film in the oxide semiconductor must be one that suppresses penetration of moisture, hydrogen, oxygen, or the like. The penetration of these impurities significantly changes the conductivity of the oxide semiconductor, impairing operational stability such as fluctuations in threshold values. _{In this regard, the conventional insulating film for protection is mainly SiO x} , SiN _x , SiON _x using a chemical vapor deposition method (CVD) or a physical vapor deposition method (PVD) such as sputtering is applied as a single layer or a multilayer. A manufacturing process, such as CVD, for forming such a high barrier property inorganic film may damage the oxide semiconductor which is the base layer of the thin film transistor using an oxide semiconductor. _{Specifically, there are SiO 2} films or SiN films as conventional protective films formed using a vacuum deposition apparatus. Since these films are formed by decomposing a source gas by plasma or the like, ion species generated by plasma in such a production process are The oxide semiconductor surface may be damaged and the film characteristics may be deteriorated. In addition, there is a concern that the oxide semiconductor will be further deteriorated due to processes such as various chemical solutions or dry etching in manufacturing the oxide semiconductor device. Therefore, for protection from the process, a protective film such as an etch stopper is also applied (Patent Document 3).

In addition, when a film-forming method using such a gas as a raw material is used, it is difficult to form a uniform protective film when manufacturing a large-screen display. Therefore, in order to solve such a point, it has been proposed to form a protective film by a coating method.

Japanese Patent Laid-Open No. 2013-211410 Japanese Patent Laid-Open No. 2013-207247 Japanese Patent Laid-Open No. 2012-235105 Japanese Patent Laid-Open No. 2013-89971

Juan Paolo Bermundo, Yasuaki Ishikawa, Haruka Yamazaki, Toshiaki Nonaka, and Yukiharu Uraoka, “Darkroom of Amorphous InGaZnO Thin-Film Transistors” Effect of polysilsesquioxane passivation layer on the dark and illuminated negative bias stress of amorphous InGaZnO thin-film transistors" March 29, 2013, 29p-F1-5 Juan Paolo Belmundo, Yasuaki Ishikawa, Haruka Yamazaki, Toshiaki Nonaka, Yukiharu Uraoka, "Effect of reactive ion etching and post-annealing conditions on the properties and reliability of InGaZnO thin film transistors with polysilsesquioxane-based passivation layers ( Effect of reactive ion etching and post-annealing conditions on the characteristics and reliability of a-InGaZnO thin-film transistors with polysilsesquioxane based passivation layer)", Preview of lectures at the 13th International Information Display Exhibition (IMID), August 26, 2013 1, p. 431 (P2-30)

However, the solution for forming a protective film used in this coating method so far mainly contains a polyimide resin or an acrylic resin. In many cases, there was room for improvement. Also, a coating type protective film using a siloxane resin has been proposed (Patent Document 4). Although this document discloses transistor characteristics in the initial stage of a semiconductor device having such a protective film, the driving stability is not sufficiently disclosed, so there is room for improvement. It is presumed that there is In addition, by using a siloxane resin as a coating type protective film and annealing the deteriorated oxide semiconductor element when the protective film is processed by dry etching at 300 ° C. A method has been proposed (Non-Patent Documents 1 and 2). However, the method of processing the protective film by dry etching or the long-time annealing of the semiconductor device at a high temperature is expensive, and there is room for further improvement in terms of production efficiency.

As a result of the present inventors examining a method for solving the above problems, a thin film transistor substrate having a protective film was formed from a photosensitive siloxane composition containing at least two types of polysiloxane having different alkali dissolution rates, a photosensitizer and a solvent by a simple method. found that it can be done. Further, it has been found that, in the thin film transistor substrate provided with such a protective film, deterioration of the thin film transistor can be suppressed, so that it is possible to impart high driving stability to the thin film transistor substrate by relatively gentle annealing. The present invention has been made based on these findings.

Accordingly, an object of the present invention is to provide a thin film transistor substrate provided with a protective film, which can provide high driving stability.

Another object of the present invention is a method for manufacturing a thin film transistor substrate having a protective film, wherein the protective film can be processed by exposure development, and high driving stability can be imparted to the thin film transistor by annealing the thin film transistor substrate. It is to provide a manufacturing method.

According to one aspect of the present invention,

thin film transistor,

A protective film made of a cured product of a photosensitive siloxane composition covering the thin film transistor

A thin film transistor substrate comprising:

The thin film transistor has a semiconductor layer made of an oxide semiconductor,

The photosensitive siloxane composition,

at least two kinds of polysiloxanes having different alkali dissolution rates;

photosensitizer and

solvent

contains

A thin film transistor substrate is provided.

In addition, according to a preferred aspect of the present invention, as the polysiloxane,

It is a polysiloxane obtained by hydrolysis and condensation of a silane compound represented by the following formula (1) and a silane compound represented by the following formula (2) in the presence of a basic catalyst, and the film after prebaking is soluble in 5 wt% tetramethylammonium hydroxide aqueous solution and polysiloxane (I) whose dissolution rate is 1000 Å/sec or less,

It is a polysiloxane obtainable by hydrolyzing and condensing at least a silane compound of the following formula (1) in the presence of an acidic or basic catalyst, and the film after prebaking is soluble in 2.38 wt% tetramethylammonium hydroxide aqueous solution, and its dissolution rate is 100 Å/ Polysiloxane (II) over seconds

Formed from a photosensitive siloxane composition comprising a, the thin film transistor substrate is provided.

Formula 1

RSi(OR ¹ ) ₃

Formula 2

Si(OR ¹ ) ₄

In Formulas 1 and 2,

R is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms in which at least one methylene may be substituted with oxygen, or 6 to 20 carbon atoms of an aryl group, or an aryl group having 6 to 20 carbon atoms in which at least one hydrogen may be substituted with fluorine,

R ¹ represents an alkyl group having 1 to 5 carbon atoms.

According to another aspect of the present invention, in the method of manufacturing the thin film transistor substrate,

at least two kinds of polysiloxanes having different alkali dissolution rates;

photosensitizer and

solvent

A process of preparing a photosensitive siloxane composition containing

applying the photosensitive siloxane composition to a thin film transistor and drying the solvent to form a protective film precursor layer;

exposing the protective film precursor layer;

developing the exposed protective film precursor layer;

forming a protective film by heating and curing the developed protective film precursor layer;

A step of annealing the thin film transistor with the heat-cured protective film at least once

A manufacturing method comprising:

ADVANTAGE OF THE INVENTION According to this invention, the thin film transistor board|substrate with a protective film which shows high stability with respect to voltage stress, optical stress, and optical/voltage stress can be provided. In the conventional coating type protective film, it is very difficult to impart high stability against stress to the thin film transistor. Further, according to the present invention, a thin film transistor capable of more simple and stable operation is realized. In addition, since a vacuum device or the like is not required, productivity can also be greatly improved.

1 is a schematic diagram showing one aspect (Example 1) of a thin film transistor substrate provided with a protective film according to the present invention.
2 is a schematic diagram showing another embodiment of a thin film transistor substrate having a protective film according to the present invention.
3 is a schematic diagram showing another embodiment of a thin film transistor substrate having a protective film according to the present invention.
4 is a graph showing the transfer characteristics of the thin film transistor substrate according to the present invention.
5 is a graph showing performance recovery by annealing the thin film transistor substrate according to Comparative Example 2. Referring to FIG.
6 is a graph showing the transfer characteristics of a thin film transistor substrate according to Comparative Example 2. Referring to FIG.
7 is a graph showing performance recovery by annealing the thin film transistor substrate according to Reference Example 1. Referring to FIG.
8 is a graph illustrating transfer characteristics of a thin film transistor substrate according to Reference Example 1. Referring to FIG.
9 is a graph showing performance recovery by annealing the thin film transistor substrate according to Reference Example 2. Referring to FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, in FIG. 1, one aspect of the thin film transistor substrate 1 provided with the protective film formed by the manufacturing method according to this invention is shown. In FIG. 1 , a gate insulating layer 3 is formed over a gate layer 2 , and a metal oxide semiconductor layer 4 is formed thereon. In addition, a source electrode 5 and a drain electrode 6 are respectively formed at both ends of the metal oxide semiconductor layer 4 so as to be in contact with the gate insulating layer 3 . In addition, although not shown in the figure, an etch stopper may be formed on the metal oxide semiconductor layer 4 . A protective film 7 is formed to cover the metal oxide semiconductor layer 4 , the source electrode 5 , and the drain electrode 6 . In another form, for example, a thin film transistor having a structure in which a source electrode 5 and a drain electrode 6 in contact with the oxide semiconductor layer 4 are formed through a contact hole 9 on the protective film 7 . The same can be applied to a substrate (FIG. 2) or a thin film transistor substrate having a top gate structure. In addition, the structure shown here is merely an example, and a thin film transistor substrate having a structure other than that shown here can also be manufactured by the manufacturing method according to the present invention.

In FIG. 3, one aspect of the thin film transistor substrate in which the pixel electrode 8 is formed on the protective film 7 is shown. The pixel electrode 8 and the drain electrode 6 are in contact through a contact hole 9 formed in the protective film.

[Thin film transistor substrate with protective film]

A thin film transistor substrate according to the present invention includes a thin film transistor and a protective film made of a cured product of a siloxane composition covering the thin film transistor. The thin film transistor substrate according to the present invention may include a plurality of passivation layers, and may have a second passivation layer on the passivation layer covering the thin film transistor. In this specification, a thin film transistor refers to the element which comprises a thin film transistor board|substrate, such as a board|substrate provided with an electrode, an electric circuit, a semiconductor layer, an insulating layer, etc. on the surface, for example. Further, examples of the wiring arranged on the substrate include a gate wiring, a data wiring, and a via wiring for connecting two or more types of wiring layers. As the semiconductor layer, an amorphous silicon semiconductor, a polycrystalline silicon semiconductor, and an oxide semiconductor are common. The thin film transistor substrate provided with the protective film which concerns on this invention is especially preferable at the point which can acquire high protective characteristic by an oxide semiconductor and an annealing process. In the past, an inorganic film such as a silicon oxide film or silicon nitride formed by PE-CVD has been applied as a protective film to enable high-temperature annealing, but reactive ion etching or the like is required to form contact holes in these inorganic films. However, since reactive ion etching remarkably accelerates the deterioration of the oxide semiconductor, it was necessary to raise the annealing temperature, which will be described later, in order to recover the performance of the semiconductor after processing. In the present invention, the protective film suppresses deterioration of the semiconductor, and high driving stability can be imparted to the thin film transistor by relatively gentle annealing.

The protective film of the thin film transistor substrate according to the present invention is formed from a photosensitive siloxane composition containing at least two types of polysiloxane having different alkali dissolution rates, a photosensitizer, and a solvent. By using such a photosensitive siloxane composition, it is possible to process a protective film by exposure development, and since pattern processing by dry etching or the like is not required, there is an advantage in that damage to thin film transistor performance is relatively small and annealing time is short. Such a photosensitive siloxane composition will be described in detail below.

[Photosensitive siloxane composition]

The photosensitive siloxane composition is classified into a positive photosensitive siloxane composition and a negative photosensitive siloxane composition according to the type of photosensitizer. Preferred positive photosensitive siloxane compositions used for forming a protective film on a thin film transistor substrate according to the present invention include at least two kinds of polysiloxanes (I) and (II) having different alkali dissolution rates, diazonaphthoquinone derivatives as photosensitizers and Contains solvent. Such a positive-type photosensitive siloxane composition forms a positive-type photosensitive layer which is removed by image development when an exposed part becomes soluble in an alkali developing solution. On the other hand, the preferable negative photosensitive siloxane composition used for forming the protective film in the thin film transistor substrate according to the present invention is at least two types of polysiloxanes (I) and (II) having different alkali dissolution rates, and an acid or a base by light. It is characterized in that it contains a curing aid and a solvent capable of generating Such a negative photosensitive siloxane composition forms the negative photosensitive layer which remains after image development because an exposed part becomes insoluble in an alkali developing solution.

<Polysiloxane>

Polysiloxane refers to a polymer having a Si-0-Si bond (siloxane bond) as a main chain. In addition, in the present specification, polysiloxane is considered to include a silsesquioxane polymer represented by _{the formula (RSiO 1.5} ) _n.

In the present invention, as the polysiloxane contained in the photosensitive siloxane composition used to form the protective film, it is preferable to use at least two kinds of polysiloxanes having different alkali dissolution rates. It is preferable to use the following polysiloxanes (I) and (II) as polysiloxane from which such an alkali dissolution rate differs. Polysiloxane (I) is a polysiloxane obtained by hydrolyzing and condensing a silane compound represented by the following formula (1) and a silane compound represented by the following formula (2) in the presence of a basic catalyst. The film after prebaking of polysiloxane (I) is soluble in a 5% by weight TMAH solution, and its dissolution rate is not more than 1000 ANGSTROM /sec, preferably from 10 to 700 ANGSTROM /sec. When the solubility is 10 angstroms/sec or more, the possibility of remaining insoluble substances after development is very low, and thus disconnection and the like are prevented, which is preferable.

Formula 1

RSi(OR ¹ ) ₃

Formula 2

Si(OR ¹ ) ₄

In Formulas 1 and 2,

R is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms in which at least one methylene may be substituted with oxygen, or an aryl group having 6 to 20 carbon atoms , or an aryl group having 6 to 20 carbon atoms in which at least one hydrogen may be substituted with fluorine,

R ¹ represents an alkyl group having 1 to 5 carbon atoms.

Polysiloxane (II) is a polysiloxane obtainable by hydrolyzing and condensing at least the silane compound of the formula (1) in the presence of an acidic or basic catalyst. The film after prebaking of polysiloxane (II) is soluble in a 2.38 wt% aqueous TMAH solution, and its dissolution rate is 100 ANGSTROM /sec or more, preferably 100 to 15,000 ANGSTROM /sec. The dissolution rate of polysiloxane (II) can be selected in the range of 100 angstroms/sec to 15,000 angstroms/sec depending on the desired thickness of the protective film. More preferably, from 100 Å/sec to 10,000 Å/sec. By setting it to 15,000 Å/sec or less, the dissolution rate difference with polysiloxane (I) is not too large, and uniform development can be performed.

Polysiloxane (I) hardly causes "pattern" sagging when the pattern after image development is heat-hardened, but cannot be used alone because its alkali solubility is very small. Further, even if the alkali solubility is adjusted to use the polysiloxane (I) or polysiloxane (II) alone, the stability of the pattern exhibited by the photosensitive siloxane composition used for forming the protective film in the present invention cannot be obtained, so that the polysiloxane (I) ) and polysiloxane (II) are preferably used in combination. Moreover, when a dissolution rate difference is large, it is preferable to use several polysiloxane (II) from which a dissolution rate differs.

The content of the silane compound of the formula (2) in the polysiloxane (I) and the polysiloxane (II) can be appropriately set depending on the use, but it is preferably 3 mol% to 40 mol% of each polysiloxane compound, and 5 mol% to 30 mol % is more preferable for controlling the hardness of the film or the thermal stability of the pattern. When the content is 3 mol% or more, the pattern stability at high temperature becomes better, and when the content is 40 mol% or less, the reaction activity can be suppressed, and the stability during storage becomes even better.

<Measurement and calculation method of alkali dissolution rate (ADR)>

The dissolution rate of the polysiloxanes (I) and (II) in the aqueous TMAH solution is measured and calculated as follows.

First, polysiloxane is dissolved in propylene glycol monomethyl ether acetate (PGMEA) in an amount of 35% by weight. The solution was spin-coated on a silicon wafer to a dry film thickness of about 2 mu m, and then the solvent was further removed by heating on a hot plate at 100 DEG C for 60 seconds. The film thickness of the coating film was measured with a spectroscopic ellipsometer (Woollam, Inc.). Next, the silicon wafer having the above film was immersed in a 5% TMAH aqueous solution for polysiloxane (I) and 2.38% TMAH aqueous solution for polysiloxane (II) at room temperature (25° C.), and the time until the film disappears was measured do. The dissolution rate is obtained by dividing the initial film thickness by the time until the film disappears. When the dissolution rate is remarkably slow, the film thickness measurement is performed after immersion for a certain period of time, and the dissolution rate is calculated by dividing the amount of film thickness change before and after immersion by the immersion time.

In any of the polymers of polysiloxane (I) and (II), the weight average molecular weight in terms of polystyrene is generally 700 to 10,000, preferably 1,000 to 4,000. If the molecular weight is within the above range, it is preferable to adjust the molecular weight within the above range, since it is possible to prevent a development residual from occurring, to obtain sufficient resolution and to obtain good sensitivity.

The mixing ratio of polysiloxane (I) and (II) can be adjusted in any ratio depending on the film thickness of the interlayer insulating film or the sensitivity and resolution of the photosensitive composition. "It is preferable because it has an anti-sagging effect. Here, "pattern" sagging is a phenomenon in which the pattern is deformed when the pattern is heated. For example, a pattern with a rectangular cross section and a clear ridge line has a rounded ridge line after heating, or a rectangular-shaped side surface that is close to vertical is It refers to a phenomenon such as inclining.

<Photosensitizer>

In the present invention, the photosensitive siloxane composition for forming a pattern by light includes various photosensitizers as a component thereof. Examples of the photosensitizer that can be used in the positive photosensitive siloxane composition include diazonaphthoquinone derivatives, and examples of the photosensitizer that can be used in the negative photosensitive siloxane composition include a curing aid that decomposes upon irradiation with light to promote condensation of silanol groups. have. Hereinafter, various photosensitizers are demonstrated.

<Diazonaphthoquinone derivative>

The diazonaphthoquinone derivative in the present invention is a compound in which naphthoquinone diazide sulfonic acid is ester-bonded to a compound having a phenolic hydroxyl group, and the structure is not particularly limited, but preferably has at least one phenolic hydroxyl group It is preferable that it is an ester compound with a compound. As naphthoquinone diazide sulfonic acid, 4-naphthoquinone diazide sulfonic acid or 5-naphthoquinone diazide sulfonic acid can be used. Since the 4-naphthoquinone diazide sulfonic acid ester compound has absorption in the i-line (wavelength 365 nm) region, it is suitable for i-line exposure. In addition, 5-naphthoquinone diazide sulfonic acid ester compound is suitable for exposure in a wide range of wavelengths because absorption exists in a wide range of wavelengths. It is preferable to select a 4-naphthoquinone diazide sulfonic acid ester compound and a 5-naphthoquinone diazide sulfonic acid ester compound according to the wavelength to be exposed. A mixture of a 4-naphthoquinone diazide sulfonic acid ester compound and a 5-naphthoquinone diazide sulfonic acid ester compound may be used.

Although it does not specifically limit as a compound which has a phenolic hydroxyl group, For example, the following compound is mentioned (a brand name, Honshu Chemical Co., Ltd. product).

The amount of diazonaphthoquinone derivative added depends on the esterification rate of naphthoquinone diazide sulfonic acid or the physical properties of the polysiloxane used, the required sensitivity, and the dissolution contrast between the exposed and unexposed areas. , preferably 3 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of the polysiloxane mixture. When the addition amount of the diazonaphthoquinone derivative is 3 parts by weight or more, the dissolution contrast between the exposed portion and the unexposed portion is increased, so that good photosensitivity is obtained. Moreover, in order to obtain still more favorable dissolution contrast, 5 weight part or more is preferable. On the other hand, colorless transparency of a cured film improves that the addition amount of a diazonaphthoquinone derivative is 20 weight part or less.

<curing aid>

As curing aids usable in the present invention, there are those that decompose upon irradiation with light to promote the condensation of silanol groups. a photoacid generator that releases an acid, which is an active material for photocuring the composition, a photobase generator that releases a base, and the like. Here, as light, visible light, an ultraviolet-ray, infrared rays, etc. are mentioned. In particular, it is preferable to generate an acid or a base by ultraviolet rays that can be used in the manufacture of thin film transistors.

The optimal amount of the curing aid to be added depends on the type of the active material generated by decomposition of the curing aid, the amount generated, the required sensitivity, and the dissolution contrast of the exposed and unexposed areas, but preferably 0. 001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight. When the addition amount is 0.001 parts by weight or more, the dissolution contrast of the exposed portion and the unexposed portion is increased, and the effect of the addition is improved. On the other hand, if the amount of the curing aid added is 10 parts by weight or less, cracking of the formed coating film is suppressed, and coloring due to decomposition of the curing aid is also suppressed, so that the colorless transparency of the coating film is improved.

Examples of the photoacid generator include diazomethane compounds, diphenyliodonium salts, triphenylsulfonium salts, sulfonium salts, ammonium salts, phosphonium salts, and sulfonimide compounds. The structure of these photo-acid generators can be represented by general formula (A).

Formula A

R ⁺ X ^-

In the above formula (A),

R ⁺ is hydrogen, an organic ion selected from the group consisting of an alkyl group modified with a carbon atom or other hetero atom, an aryl group, an alkenyl group, an acyl group and an alkoxyl group, for example, a diphenyliodonium ion or triphenylsulf phonium ion.

Further, X ⁻ is preferably any of a counter ion represented by the following formula.

In the above formulas,

Y is a halogen atom,

R ^a is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms substituted with a substituent selected from fluorine, a nitro group and a cyano group,

R ^b is hydrogen or an alkyl group having 1 to 8 carbon atoms,

p is a number from 0 to 6,

q is a number from 0 to 4.

Specific counter ions include BF ₄ ^- , (C ₆ F ₅ ) ₄ B ^- , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ B ^- , PF ₆ ^- , (CF ₃ CF ₂ ) ₃ PF ₃ ^- , SbF ₆ ^- , (C ₆ F ₅ ) ₄ Ga ^- , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ Ga ^- , SCN ^- , (CF ₃ SO ₂ ) ₃ C ^- , (CF ₃ SO ₂ ) ₂ N ^- , a group consisting of formate ion, acetate ion, trifluoromethanesulfonic acid ion, nonafluorobutanesulfonic acid ion, methanesulfonic acid ion, butanesulfonic acid ion, benzenesulfonic acid ion, p-toluenesulfonic acid ion and sulfonic acid ion may be selected from

Among the photo-acid generators that can be used in the present invention, it is particularly preferable to generate sulfonic acids or boric acids, for example, tolylcumyliodonium tetrakis(pentafluorophenyl)boric acid (Rhodia), PHOTOINITIATOR 2074 (trade name)), diphenyliodonium tetra(perfluorophenyl)boric acid, a cation moiety composed of a sulfonium ion, and an anion moiety composed of a pentafluoroborate ion, and the like. In addition, triphenylsulfonium trifluoromethanesulfonic acid, triphenylsulfonium camphorsulfonic acid, triphenylsulfonium tetra (perfluorophenyl) boric acid, 4-acetoxyphenyldimethylsulfonium hexafluoroarsenic acid, 1 -(4-n-Butoxynaphthalen-1-yl)tetrahydrothiopheniumtrifluoromethanesulfonic acid, 1-(4,7-dibutoxy-1-naphthalenyl)tetrahydrothiopheniumtrifluoro Methanesulfonic acid, diphenyliodonium trifluoromethanesulfonic acid, diphenyliodonium hexafluoroarsenic acid, etc. are mentioned. In addition, a photoacid generator represented by the following formula can also be used.

In the above formulas,

A is each independently selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkyl carbonyl group having 1 to 20 carbon atoms, an aryl carbonyl group having 6 to 20 carbon atoms, a hydroxyl group and an amino group. a selected substituent;

p is each independently an integer from 0 to 5,

B ^- may be a fluorinated alkylsulfonate group, a fluorinated arylsulfonate group, a fluorinated alkylborate group, an alkylsulfonate group or an arylsulfonate group.

It is also possible to use a compound in which the cation and anion represented by these formulas are interchanged, or a photoacid generator in which the cation or anion represented by these formulas is combined with the various cations or anions described above. For example, any of the sulfonium ions represented by the above formula are combined with tetra(perfluorophenyl)borate ions, or any of the iodonium ions represented by the above formulas and tetra(perfluorophenyl)borate ions are combined A combination can also be used as a photo-acid generator.

As an example of the said photobase generator, the polysubstituted amide compound which has an amide group, a lactam, an imide compound, or the thing containing the said structure is mentioned.

Examples of the thermal base generator include N-(2-nitrobenzyloxycarbonyl)imidazole, N-(3-nitrobenzyloxycarbonyl)imidazole, N-(4-nitrobenzyloxycarbonyl)imidazole, imidazole derivatives such as N-(5-methyl-2-nitrobenzyloxycarbonyl)imidazole and N-(4-chloro-2-nitrobenzyloxycarbonyl)imidazole; 1,8-diazabicyclo(5) ,4,0)undecene-7, tertiary amines, quaternary ammonium salts, and mixtures thereof. These base generators can be used alone or in combination as in the acid generator.

<solvent>

As a solvent, For example, ethylene glycol monoalkyl ethers, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl Diethylene glycol dialkyl ethers such as ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate, PGMEA, propylene glycol mono Propylene glycol alkyl ether acetates such as ethyl ether acetate and propylene glycol monopropyl ether acetate, aromatic hydrocarbons such as benzene, toluene, and xylene, methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Ketones, etc. are mentioned. These solvents can be used individually, respectively, or can be used in combination of 2 or more type. The compounding ratio of the solvent varies depending on the application method or the requirement of the film thickness after application. For example, in the case of spray coating, it is 90% by weight or more, based on the total weight of the polysiloxane and optional components, but in the slit application of large glass substrates used in the manufacture of displays, it is generally 50% by weight or more, preferably 60% by weight. % by weight or more, generally 90% by weight or less, preferably 85% by weight or less.

<Optional ingredients>

In addition, the photosensitive siloxane composition according to the present invention may include other optional components as needed. Surfactants etc. are mentioned as such a component.

Among these, it is preferable to use a surfactant in order to improve the coatability. Examples of the surfactant that can be used in the photosensitive siloxane composition of the present invention include nonionic surfactants, anionic surfactants, and amphoteric surfactants.

As said nonionic surfactant, For example, polyoxyethylene alkyl ethers, such as polyoxyethylene alkyl ether, For example, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, or Acetylene glycol derivatives, such as polyoxyethylene fatty acid diester, polyoxy fatty acid monoester, polyoxyethylene polyoxypropylene block polymer, acetylene alcohol, acetylene glycol, polyethoxylate of acetylene alcohol, and polyethoxylate of acetylene glycol, fluorine Containing surfactants such as Prorad (trade name, manufactured by Sumitomo 3M Co., Ltd.), Megapack (trade name, manufactured by DIC Corporation), sulfron (trade name, manufactured by Asahi Glass, Ltd.), or organic siloxane interface Activators such as KP341 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. Examples of the acetylene glycol include 3-methyl-1-butyn-3-ol, 3-methyl-1-penty-3-ol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7 ,9-tetramethyl-5-decyne-4,7-diol, 3,5-dimethyl-1-hexyn-3-ol, 2,5-dimethyl-3-hexyne-2,5-diol, 2,5- Dimethyl-2,5-hexanediol etc. are mentioned.

Moreover, as anionic surfactant, the ammonium salt or organic amine salt of alkyldiphenyl ether disulfonic acid, the ammonium salt or organic amine salt of alkyldiphenyl ether sulfonic acid, the ammonium salt or organic amine salt of alkylbenzene sulfonic acid, polyoxy ammonium salts or organic amine salts of ethylene alkyl ether sulfuric acid, ammonium salts or organic amine salts of alkyl sulfuric acid, and the like.

Further, examples of the amphoteric surfactant include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, amide propylhydroxysulfone lauryl acid and the like.

These surfactants may be used alone or in mixture of two or more, and the mixing ratio thereof is usually 50 to 10,000 ppm, preferably 100 to 5,000 ppm, based on the total weight of the photosensitive siloxane composition.

[Method for manufacturing thin film transistor with protective film]

A thin film transistor substrate provided with a protective film (cured film) can be obtained by apply|coating a photosensitive siloxane composition to a thin film transistor and heating. At this time, a pattern such as a contact hole is formed by performing exposure and development through a desired mask.

As a method of manufacturing a thin film transistor substrate having an oxide semiconductor layer, a bottom gate type TFT shown in FIG. 1 will be described as an example. A gate electrode 2 is patterned on a substrate made of glass or the like. As the gate electrode material, materials such as molybdenum, aluminum and aluminum alloys, copper and copper alloys, and titanium are constituted as a single layer or a laminated film of two or more types. A gate insulating film 3 is formed over the gate electrode. As a gate insulating film, a silicon oxide film, a silicon nitride film, a silicon nitride oxide film, etc. are generally formed by the PE-CVD method. The thickness of the gate insulating film is usually 100 to 300 nm. The oxide semiconductor layer 4 on the gate insulating film is formed by a sputtering method in which a sputtering target having the same composition as that of the oxide semiconductor is formed by DC sputtering or RF sputtering, or a precursor solution such as a metal alkoxide, a metal organic acid salt, a chloride, or oxide semiconductor nanoparticles. There is a liquid phase method in which an oxide semiconductor layer is formed by applying a dispersion of After the oxide semiconductor layer 4 is patterned, the source/drain electrodes 5 and 6 are patterned. As the source/drain electrode material, materials such as molybdenum, aluminum and aluminum alloys, copper and copper alloys, and titanium are constituted as a single layer or a laminated film of two or more types.

In the method for manufacturing a thin film transistor substrate having a protective film, a photosensitive siloxane composition is applied on the thin film transistor having an oxide semiconductor layer, dried by prebaking, etc., and then exposed to light, followed by exposure to an aqueous solution of tetramethylammonium hydroxide (generally, 2.38% aqueous solution is used) to form a pattern such as contact holes, and then the applied photosensitive siloxane composition (protective film precursor layer) is cured to form a protective film 7 . Further, on the protective film, an ITO film is formed by, for example, sputtering, and patterned to form the element in Fig. 3 . It is also possible to form an inorganic film on the protective film by CVD or PVD, or to have an organic material for the purpose of a protective film or planarization by a coating method.

Each step of the manufacturing method according to the present invention will be described below.

<Step of preparing the photosensitive siloxane composition>

In the method for manufacturing a thin film transistor substrate with a protective film according to the present invention, a photosensitive siloxane composition containing at least two types of polysiloxane having different alkali dissolution rates, a photosensitizer, and a solvent is prepared. Detailed description of each component of the photosensitive siloxane composition is as described above.

<Applying process>

The application process in the present invention is performed by applying the photosensitive siloxane composition to the surface of the thin film transistor. Such an application process is a general application method, that is, dip coating, roll coating, bar coating, brush coating, spray coating, doctor coating, flow coating, spin coating, slit coating, etc., conventional photosensitive composition It can be carried out by any method known as a method of applying the . A protective film precursor layer can be formed to a desired film thickness by repeatingly apply|coating once or twice or more as needed.

<Pre-baking process>

After forming the protective film precursor layer, in order to further dry the layer and further reduce the residual amount of the solvent, it is preferable to prebaking (heat treatment) the layer. The pre-baking process is carried out in a clean oven, generally at a temperature of 70 to 150° C., preferably 90 to 130° C., for 10 to 180 seconds, preferably 30 to 90 seconds in the case of a hot plate. In the case of by, it can be carried out for 1 to 5 minutes. Preferably, a solvent removal process by spin or vacuum is included prior to pre-baking.

<Exposure process>

After the protective film precursor layer is formed, the surface thereof is irradiated with light. As a light source used for light irradiation, any thing conventionally used for the pattern formation method can be used. As such a light source, lamps, such as a high pressure mercury vapor lamp, a low pressure mercury lamp, a metal halide, and xenon, a laser diode, LED, etc. are mentioned. As the irradiated light, ultraviolet rays such as g-rays, h-rays, and i-rays can be generally used. Except for ultra-fine processing such as semiconductors, it is common to use light (high pressure mercury lamp) of 360 to 430 nm for patterning from several μm to several tens of μm. Among these, in the case of a liquid crystal display device, 430 nm light is used in many cases. Although the energy of the irradiated light also depends on the film thickness of the light source or the protective film precursor layer, it is generally 20 to 2000 mJ/cm 2 , preferably 50 to 1000 mJ/cm 2 for the positive type of the diazonaphthoquinone derivative. When the irradiation light energy is lower than 20 mJ/cm 2 , sufficient resolution may not be obtained. Conversely, if it is higher than 2000 mJ/cm 2 , excessive exposure may occur, resulting in generation of halation. Moreover, in the case of a negative type, it is 1-50mJ/cm<2>, Preferably it is 10-100mJ/cm<2>. When the irradiation light energy is lower than 1 mJ/cm 2 , the film reduction is large, and conversely, when it is higher than 500 mJ/cm 2 , the exposure becomes excessive and resolution cannot be obtained in some cases.

In order to irradiate light in a pattern shape, a general photomask may be used. Such photomasks may be arbitrarily selected from those well known. Although the environment at the time of irradiation is not specifically limited, Generally, an ambient atmosphere (atmospheric air) or a nitrogen atmosphere is preferable. In addition, when forming a film on the entire surface of the substrate, it is preferable to irradiate the entire surface of the substrate with light. In the present invention, the patterned film also includes a case in which a film is formed on the entire surface of the substrate.

<Post-exposure heating process>

After exposure, in order to promote the reaction between the polymers in the film by the reaction initiator generated at the exposure site, post exposure baking may be performed if necessary. This heat treatment is not performed to completely harden the protective film precursor layer, but is performed so that only a desired pattern remains on the substrate after development and the other portions can be removed by development.

<Development process>

After exposure, if necessary, post-exposure heating is performed, and then the protective film precursor layer is developed. As a developer that can be used during development, any developer used for developing a conventionally known photosensitive siloxane composition may be used. In the present invention, an aqueous solution of tetramethylammonium hydroxide (TMAH) is used to specify the dissolution rate of polysiloxane, but the developer used when forming the cured film is not limited thereto. As a preferred developer, an alkali which is an aqueous solution of an alkaline compound such as tetraalkylammonium hydroxide, choline, alkali metal hydroxide, alkali metal metasilicate (hydrate), alkali metal phosphate (hydrate), ammonia, alkylamine, alkanolamine, and heterocyclic amine. a developing solution is mentioned, and an especially preferable alkaline developing solution is TMAH aqueous solution. These alkaline developing solutions may further contain water-soluble organic solvents, such as methanol and ethanol, or surfactant as needed. The developing method may also be arbitrarily selected from conventionally known methods. Specific examples include methods such as immersion in a developer (dip), paddle, shower, slit, cap coating, and spraying. A pattern can be obtained by such a phenomenon. It is preferable to wash with water after developing with a developer. Further, in the manufacturing method according to the present invention, as shown in Fig. 3, a transparent electrode (pixel electrode) formed on the drain electrode 6 and the protective film 7 via the contact hole 9 formed by development. (8)) can also be made conduction|electrical_connection.

<Post-development Irradiation Process>

When a protective film formed using a positive composition is used as a transparent film, it is preferable to perform light irradiation called bleaching exposure. By performing the bleaching exposure, the unreacted diazonaphthoquinone derivative remaining in the film is photolyzed, and the optical transparency of the film is further improved. As a method of bleaching exposure, a high-pressure mercury lamp, a low-pressure mercury lamp, etc. are used to expose the entire surface at about 100 to 2,000 mJ/cm 2 (in terms of wavelength 365 nm exposure dose) depending on the film thickness. Further, in the case of the negative type, by activating the curing aid remaining in the film after development by light irradiation, subsequent heat curing can be performed more easily. Depending on the film thickness, about 100 to 2,000 mJ/cm 2 (in terms of wavelength 365 nm exposure dose) is exposed over the entire surface.

<Heat hardening (calcination) process>

The firing temperature at the time of curing the protective film precursor layer may be arbitrarily selected as long as it is a temperature at which the protective film is cured. However, when the calcination temperature is too low, the reaction may not proceed sufficiently and the curing may not be sufficiently performed. For this reason, it is preferable that it is 200 degreeC or more, and, as for a calcination temperature, it is more preferable that it is 250 degreeC or more. In addition, when the temperature is excessively high, the production cost may increase or the polymer may be decomposed. Therefore, it is preferably 500°C or less, and more preferably 400°C or less. In addition, although the calcination time is not specifically limited, Generally, it is 10 minutes or more, Preferably it is 20 minutes or more. Firing is carried out in an inert gas or atmosphere.

<Annealing process>

In addition, after formation of the thin film transistor with a protective film, annealing of the thin film transistor is performed. In particular, in devices using oxide semiconductors, thin film transistor performance deteriorates due to film formation by PVD or CVD, pattern processing such as dry etching or wet etching, and resist stripping, so it is difficult to restore performance by annealing. desirable. In the present invention, by performing annealing at 250° C. or higher after the formation of the protective film, the performance of the thin film transistor, which was once degraded during processing, is recovered. In particular, in the present invention, a thin film transistor having a greatly deteriorated oxide semiconductor layer is characterized in that it induces significant performance recovery by annealing in the presence of oxygen. By increasing the annealing temperature or lengthening the annealing time according to the degree of deterioration of the oxide semiconductor, the performance recovery of the thin film transistor and the reliability of the device can be improved. Annealing temperature is 250 degreeC or more and 450 degrees C or less, Preferably they are 300 degreeC or more and 400 degrees C or less. The annealing time is 30 minutes or more, preferably 60 minutes or more, but from the viewpoint of cost and production efficiency, it is more preferably 60 minutes or more and less than 120 minutes. The annealing is preferably performed in the presence of oxygen. In the case of a thin film transistor substrate provided with a protective film formed by a conventional organic coating film, since annealing at such a high temperature could not be performed, a significant performance recovery by annealing could not be achieved. However, in the annealing in the presence of oxygen, it is preferable to perform the annealing at 400° C. or less in consideration of the effects of oxidation of the electrode or coloring due to oxidation of the protective film of the present invention. In addition, since the protective film formed of the photosensitive siloxane composition of the present invention has photosensitivity, it is not necessary to perform pattern processing by dry etching or the like, so there is an advantage in that the performance of the thin film transistor is relatively less damaged and the annealing time is short.

Example

The present invention will be described in more detail through examples as follows.

Synthesis Example 1 (Synthesis of polysiloxane (I))

In a 2L flask equipped with a stirrer, a thermometer, and a cooling tube, 36.5 g of 25 wt% tetramethylammonium hydroxide (TMAH) aqueous solution, 300 ml of isopropyl alcohol (IPA), and 1.5 g of water were injected, followed by a dropping lot (lot). ), a mixed solution of 44.6 g of phenyltrimethoxysilane, 34.1 g of methyltrimethoxysilane, and 3.8 g of tetramethoxysilane was prepared. The mixed solution was added dropwise at 60° C., stirred at the same temperature for 3 hours, and then neutralized by adding 10% HCl aqueous solution. 200 ml of toluene and 300 ml of water were added to the neutralized solution, and the organic layer obtained by separating into two layers was concentrated under reduced pressure to remove the solvent, and propylene glycol monomethyl ether acetate was obtained so that the concentration of solid content in the concentrate was 40% by weight. (PGMEA) was added. The molecular weight (in terms of polystyrene) of the obtained polysiloxane (I) was a weight average molecular weight (Mw) = 1,420. The obtained resin solution was applied to a silicon wafer so that the film thickness after prebaking became 2 mu m, and the dissolution rate in 5% TMAH aqueous solution was measured. As a result, it was 950 angstroms/sec.

Synthesis Example 2 (Synthesis of polysiloxane (II))

In a 2L flask equipped with a stirrer, a thermometer, and a cooling tube, 36.5 g of 25 wt% aqueous TMAH solution, 800 ml of IPA, and 2.0 g of water were charged, and then 39.7 g of phenyltrimethoxysilane and 34.1 methyltrimethoxysilane were added to the dropping funnel. g and a mixed solution of 7.6 g of tetramethoxysilane was prepared. The mixed solution was added dropwise at 10°C, stirred at the same temperature for 24 hours, and then neutralized by adding 10% HCl aqueous solution. 400 ml of toluene and 100 ml of water were added to the neutralized solution, and the organic layer obtained by separating into two layers was concentrated under reduced pressure to remove the solvent, and PGMEA was added to the concentrate so that the concentration of the solid content was 40% by weight. The molecular weight (in terms of polystyrene) of the obtained polysiloxane (II) was Mw=2,200. The obtained resin solution was applied to a silicon wafer so that the film thickness after prebaking became 2 mu m, and the dissolution rate in 2.38% TMAH aqueous solution was measured. As a result, it was 490 angstroms/sec.

Positive photosensitive siloxane composition A

After mixing in the ratio of polysiloxane (I):(II)=(80% by weight):(20% by weight), the polysiloxane mixture was adjusted with 35% PGMEA solution, and 4-4'-(1-(4-( 1-(4-hydroxyphenol)-1-methylethyl)phenyl)ethylidene)bisphenol 2.0 molar modified form of diazonaphthoquinone (hereinafter abbreviated as “PAC”) was added in an amount of 12% by weight based on polysiloxane . Further, as a surfactant, KF-53 manufactured by Shin-Etsu Chemical Co., Ltd. was added in an amount of 0.3% by weight based on the polysiloxane to obtain a photosensitive siloxane composition A.

Example 1 (Thin film transistor substrate provided with a protective film according to the present invention)

On the n-doped silicon wafer, a 100 nm silicon oxide film was provided as a gate insulating film. Amorphous InGaZnO was deposited on the gate insulating film by RF sputtering (70 nm). After the amorphous InGaZnO film was patterned, the source/drain electrodes were patterned. Molybdenum was used as the source/drain electrode material. Thereafter, the thin film transistor was annealed at 300° C. for 1 hour. Then, as a protective film, the positive photosensitive siloxane composition A was applied by spin coating. After prebaking at 100 DEG C for 90 seconds, contact holes were formed by exposure and development.

Then, it was cured under a nitrogen atmosphere at 250° C. for 60 minutes to form a protective film. The thin film transistor provided with the said protective film was annealed. Annealing was performed at 250° C. under an oxygen atmosphere for 1 hour. The protective film thickness was 400 nm. The transfer characteristic of the thin film transistor with the said protective film after annealing is shown in FIG. The characteristics hardly changed with respect to the constant voltage applied stress, so that good transfer characteristics of the thin film transistor could be obtained.

Comparative Example 1 (Thin film transistor substrate provided with a protective film containing a photosensitizer and one kind of polysiloxane)

The polysiloxane (II) was adjusted with a 35% solution of PGMEA, diazona of 4-4'-(1-(4-(1-(4-hydroxyphenol)-1-methylethyl)phenyl)ethylidene)bisphenol Ptoquinone 2.0 molar modified form (hereinafter abbreviated as "PAC") was added in an amount of 12% by weight based on polysiloxane (II). In addition, as a surfactant, KF-53 manufactured by Shin-Etsu Chemical Co., Ltd. was added in an amount of 0.3% by weight based on the polysiloxane to obtain a photosensitive siloxane composition B. As in Example 1, the photosensitive siloxane composition B was applied as a protective film by spin coating. After prebaking at 100 DEG C for 90 seconds, contact holes were formed by exposure and development. Subsequently, as a result of curing under a nitrogen atmosphere at 250° C. for 60 minutes, the contact holes formed by the development were lost by heat flow, so that the transistor characteristics could not be measured.

Comparative Example 2 (Thin film transistor substrate without protective film)

On the gate electrode, a 100 nm silicon oxide film was provided as a gate insulating film. Amorphous InGaZnO was deposited on the gate insulating film by RF sputtering. After the amorphous InGaZnO film was patterned, the source/drain electrodes were patterned. Molybdenum was used as the source/drain electrode material. The protective film was not provided, and the thin film transistor without the said protective film was annealed. Annealing was performed at 300° C. for 2 hours. As shown in FIG. 5, performance recovery by annealing was insufficient. 6 shows the transfer characteristics of the thin film transistor. Characteristics greatly changed with respect to constant voltage applied stress, and unstable transfer characteristics of thin film transistors were obtained.

Reference Example 1 (Thin film transistor substrate provided with a protective film containing one type of polysiloxane)

Methylphenylsilsesquioxane (methyl group: phenyl group = 60 mol: 40 mol) was synthesized in the presence of a basic catalyst. The molecular weight (in terms of polystyrene) was Mw=1,800. It was mostly insoluble in 5% aqueous TMAH solution, and the dissolution rate was almost 0 Å/sec. The obtained polymer was adjusted with a 35% PGMEA solution, and as a surfactant, KF-53 manufactured by Shin-Etsu Chemical Co., Ltd. was added in an amount of 0.3% by weight based on polysiloxane to obtain a siloxane composition C. After spin coating of siloxane composition C on the amorphous InGaZnO prepared in the same manner as in Example 1, prebaking at 100° C. for 90 seconds, and curing (300° C., 1 hour, in nitrogen) to form a protective film. After the contact holes were formed by dry etching, the thin film transistor was annealed at 300° C. for 1 hour in an oxygen atmosphere. 7 shows the transfer characteristics of the thin film transistor. Characteristic deterioration due to dry etching after application of the protective film was found. In addition, properties close to the initial properties were exhibited by annealing. As a result of verifying the characteristic change due to the stress application, a large characteristic change was confirmed as shown in FIG. 8 .

Reference Example 2 (Thin Film Transistor Substrate with Protective Film Containing Acrylic Material)

A composition comprising an acrylic resin comprising a polymer of 2-hydroxyethyl methacrylate and a silane monomer containing a vinyl group (Shin-Etsu Chemical KBM-5103) and methylphenylsilsesquioxane synthesized in Comparative Example 3 was prepared. The acrylic resin was added in an amount of 30% by weight based on 100% by weight of methylphenylsilsesquioxane. As in the examples, a 35% solution was prepared by adding a surfactant. In the same manner as in Comparative Example 3, a protective film was formed on the amorphous InGaZnO, contact holes were formed by dry etching, and then the thin film transistor was annealed at 300° C. for 1 hour in an oxygen atmosphere. 9 shows the transfer characteristics of the thin film transistor before and after annealing. Even after annealing, good transistor characteristics could not be obtained, such as a high current flowing in the negative voltage region.

1 Thin film transistor substrate with protective film
2 gate layer
3 gate insulating layer
4 metal oxide semiconductor layer
5 source electrode
6 drain electrode
7 Shield
8 pixel electrode
9 contact hole

Claims (9)

delete delete delete delete delete delete A method of manufacturing a thin film transistor substrate comprising: a thin film transistor having a semiconductor layer made of an oxide semiconductor; and a protective film made of a cured product of a photosensitive siloxane composition covering the thin film transistor,
at least two kinds of polysiloxanes having different alkali dissolution rates;
photosensitizer and
solvent
A process of preparing a photosensitive siloxane composition containing
applying the photosensitive siloxane composition to a thin film transistor and drying the solvent to form a protective film precursor layer;
exposing the protective film precursor layer;
developing the exposed protective film precursor layer;
forming a protective film by heating and curing the developed protective film precursor layer; and
A step of annealing the thin film transistor with the heat-cured protective film at least once
comprising, a manufacturing method. The method according to claim 7, wherein the annealing is performed at 250°C or higher and 450°C or lower. The method according to claim 7, wherein the annealing is performed at a temperature of 250°C or higher and 400°C or lower under an oxygen atmosphere.

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