JP2011222788A - Thin-film transistor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a TFT substrate with superior switching characteristics that can be manufactured through simple processes.SOLUTION: The invention provides a thin-film transistor substrate comprising a substrate and a thin-film transistor, the thin film transistor comprising an oxide semiconductor layer composed of a oxide semiconductor and formed on the substrate and a semiconductor-layer-contacting-insulation layer formed in contact with the oxide semiconductor layer. At least one of the semiconductor-layer-contacting-insulation layer included in the thin-film transistor is a photosensitive polyimide insulation layer formed with a photosensitive polyimide resin composition.

Description

  The present invention relates to a thin film transistor substrate that can be manufactured by a simple process and has excellent switching characteristics.

  In recent years, semiconductor transistors typified by thin film transistors (hereinafter sometimes referred to as TFTs) tend to expand their applications with the development of display devices. Such a semiconductor transistor functions as a switching element when electrodes are connected via a semiconductor material.

As an insulating layer such as a gate insulating layer and a passivation layer used in a TFT, generally, an inorganic compound such as silicon oxide is used, and these are formed by a vapor deposition method (Patent Document 1, etc.). .
However, when an insulating layer is formed using such a vapor deposition method, resist patterning, inorganic compound etching, and resist peeling are performed in order to form vacuum equipment necessary for vapor deposition and a patterned insulating layer. There is a problem that a complicated process such as this is required and the cost becomes high. In addition, an insulating layer using an inorganic compound has a problem that cracks are easily generated when used for a flexible substrate. Furthermore, it is difficult to increase the thickness of the insulating layer using an inorganic compound, and there is a problem that a short circuit may occur when there is foreign matter such as dust on the gate electrode, the source / drain electrode, or the pixel electrode. .

With respect to such a problem, when a resin insulating layer using a resin is used, it can be manufactured by a simple process as compared with an inorganic compound insulating layer. Moreover, since the vacuum equipment required for vapor deposition can be eliminated, the cost can be reduced. Moreover, when it uses for the board | substrate use which covers a flexible nest, it can be set as a thing which a crack does not enter easily. Further, when such an insulating layer made of resin is used, the thickness can be easily increased unlike the insulating layer made of the above-mentioned inorganic compound. Therefore, even when foreign matter or the like is mixed, occurrence of problems such as a short circuit can be suppressed.
However, when such a resin insulating layer is used as a TFT, there is a problem that the characteristics required for the TFT cannot be sufficiently satisfied, for example, the switching characteristics are deteriorated.

JP 2000-324368 A

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a TFT substrate that can be manufactured by a simple process and has excellent switching characteristics.

  In order to solve the above problems, the present invention includes a substrate, an oxide semiconductor layer formed on the substrate and made of an oxide semiconductor, and a semiconductor layer contact insulating layer formed so as to be in contact with the oxide semiconductor layer. A TFT substrate, wherein at least one of the semiconductor contact insulating layers included in the TFT is a photosensitive polyimide insulating layer formed using a photosensitive polyimide resin composition. provide.

According to the present invention, at least one of the semiconductor layer contact insulating layers included in the TFT is the photosensitive polyimide insulating layer, that is, formed using the photosensitive polyimide resin composition. It can be made excellent in workability, heat resistance and insulation, can be manufactured by a simple process, and can be excellent in switching characteristics.
In addition, since the oxide semiconductor has excellent semiconductor characteristics among semiconductor materials, the oxide semiconductor layer can have excellent semiconductor characteristics.
Further, when the photosensitive polyimide insulating layer is formed using a photosensitive polyimide resin composition containing a polyimide precursor, it is necessary to imidize the polyimide precursor by a dehydration ring-closing reaction by annealing treatment. is there. Further, water is generated simultaneously with this imidization. When such an annealing treatment in the presence of water, that is, a water vapor annealing treatment is performed, the polyimide precursor can be imidized and at the same time the semiconductor characteristics of the oxide semiconductor can be improved, and the switching characteristics are superior. Because it can be. That is, by having both the oxide semiconductor layer and the photosensitive polyimide insulating layer, it can be manufactured particularly by a simple process and can have excellent switching characteristics.

  In the present invention, the photosensitive polyimide resin composition preferably contains a polyimide component and a photosensitive component, and the polyimide component preferably contains a polyimide precursor. This is because, as described above, steam annealing of the oxide semiconductor can be performed simultaneously with imidization of the polyimide precursor, and the switching characteristics can be improved with a simple process.

  In the present invention, the 5% weight reduction temperature of the photosensitive polyimide resin composition is preferably 450 ° C. or higher. This is because the photosensitive polyimide insulating layer can be reduced in outgas and can be excellent in switching characteristics.

  In this invention, the said photosensitive polyimide resin composition contains a polyimide component and a photosensitive component, and content of the said photosensitive component is 0.1 weight with respect to 100 weight part of said polyimide components. It is preferable to be within the range of not less than 30 parts by weight. This is because the photosensitive polyimide insulating layer can have less outgas and can have excellent switching characteristics.

  In the present invention, the photosensitive polyimide resin composition contains a polyimide component and a photosensitive component, and the photosensitive component contains a photoacid generator or a photobase generator as a main component. Is preferred. This is because the amount of outgas can be reduced.

  In the present invention, the photosensitive component is preferably a photobase generator. This is because the influence on the metal or the like contained in the TFT substrate of the present invention can be reduced.

  In the present invention, the base generated in the photobase generator is preferably an aliphatic amine or amidine. It is because it can be excellent in the catalytic effect and the like.

  In the present invention, the 5% weight loss temperature of the photobase generator is preferably in the range of 150 ° C to 300 ° C. This is because the low outgas polyimide insulating layer can be easily formed and the amount of outgas generation can be reduced.

  In the present invention, the photobase generator is preferably one represented by the following formula (a).

(In Formula (a), R ²¹ and R ²² are each independently hydrogen or a monovalent organic group, and may be the same or different. R ²¹ and R ²² are bonded to each other. May form a cyclic structure and may contain a heteroatom bond, provided that at least one of R ²¹ and R ²² is a monovalent organic group R ²³ , R ²⁴ , R ²⁵ And R ²⁶ are each independently hydrogen, halogen, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group. , phosphonato group, an amino group, an ammonio group or a monovalent organic group, may be different even in the same ^{.R 23, R 24,} R ²⁵ and ^{R 26,} those two or more binding And it may form a cyclic structure, may contain a binding heteroatom.)

  In the present invention, at least one of the gate insulating layer in the top gate type TFT or the gate insulating layer and the passivation layer in the bottom gate type TFT among the semiconductor layer contact insulating layer is at least the photosensitive polyimide. An insulating layer is preferred. This is because the switching characteristics can be improved.

In the present invention, of the semiconductor layer contact insulating layer, the gate insulating layer in the top gate type TFT or the passivation layer in the bottom gate type TFT is preferably at least the photosensitive polyimide insulating layer. .
The gate insulating layer in the top gate type TFT and the passivation layer in the bottom gate type TFT are usually formed so as to cover the oxide semiconductor layer. Therefore, when the photosensitive polyimide resin composition contains a polyimide precursor, the photosensitive polyimide insulating layer is coated with the photosensitive polyimide resin composition after the formation of the oxide semiconductor layer, and then imidized. Is formed. Accordingly, the water vapor annealing treatment of the oxide semiconductor layer can be performed simultaneously with imidization without separately performing the water vapor annealing treatment of the oxide semiconductor layer, and the switching characteristics can be easily improved. Because.

In the present invention, the substrate is preferably a flexible substrate having a metal foil and a planarizing layer formed on the metal foil and containing polyimide.
By having the planarization layer, since the planarization layer containing polyimide is formed on the metal foil, unevenness on the surface of the metal foil can be planarized, and deterioration of the electrical performance of the TFT can be prevented. Because it can. In addition, the photosensitive polyimide insulating layer is different from an insulating layer made of an inorganic material because it does not cause defects such as cracks even when the substrate is a flexible substrate.

In the present invention, the flexible substrate preferably has an adhesion layer containing an inorganic compound on the planarizing layer.
By having the adhesion layer, the adhesion to the TFT can be improved, and even when the dimensions of the planarization layer containing polyimide change due to the application of moisture or heat during the production of the TFT substrate. This is because peeling and cracking can be prevented from occurring in the electrodes and oxide semiconductor layers constituting the TFT.

  The present invention is advantageous in that it can be manufactured by a simple process and a TFT substrate having excellent switching characteristics can be provided.

It is a schematic sectional drawing which shows an example of the TFT substrate of this invention. It is a schematic sectional drawing which shows the other example of the TFT substrate of this invention. It is a schematic sectional drawing which shows the other example of the TFT substrate of this invention. It is a schematic sectional drawing which shows an example of the flexible substrate used for this invention. It is a schematic sectional drawing which shows the other example of the flexible substrate used for this invention.

The present invention relates to a TFT substrate.
Hereinafter, the TFT substrate of the present invention will be described in detail.

  The TFT substrate of the present invention includes a substrate, a TFT having an oxide semiconductor layer formed on the substrate and made of an oxide semiconductor, and a semiconductor layer contact insulating layer formed in contact with the oxide semiconductor layer. And at least one of the semiconductor layer contact insulating layers included in the TFT is a photosensitive polyimide insulating layer formed using a photosensitive polyimide resin composition.

Such a TFT substrate of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a TFT substrate of the present invention. As illustrated in FIG. 1A, the TFT substrate 20 of the present invention is formed on the metal foil 1, the planarizing layer 2 formed on the metallic foil 1 and containing polyimide, and the planarizing layer 2. Flexible substrate 10 having adhesion layer 3 containing an inorganic compound, source electrode 12S and drain electrode 12D and oxide semiconductor layer 11 formed on adhesion layer 3 of flexible substrate 10, and source electrode 12S and drain electrode. 12D and the oxide semiconductor layer 11 have a gate insulating layer 14 formed using the photosensitive polyimide resin composition, and a gate electrode 13G formed on the gate insulating layer 14. It has a gate / bottom contact structure.
1B includes a TFT having a top gate / top contact structure, and includes an oxide semiconductor layer 11 and a source electrode 12S formed on the adhesion layer 3 of the flexible substrate 10. A gate insulating layer 14 formed on the oxide semiconductor layer 11 and the source electrode 12S and the drain electrode 12D by using the photosensitive polyimide resin composition; and a gate formed on the gate insulating layer 14. And an electrode 13G.

As another example of the TFT substrate of the present invention, as illustrated in FIG. 2A, the TFT substrate 20 includes a TFT having a bottom gate / bottom contact structure, and the adhesion layer 3 of the flexible substrate 10. A gate electrode 13G formed thereon, a gate insulating layer 14 formed using the photosensitive polyimide resin composition so as to cover the gate electrode 13G, and a source electrode 12S formed on the gate insulating layer 14 And the drain electrode 12D and the oxide semiconductor layer 11, and the passivation layer 15 formed on the source electrode 12S, the drain electrode 12D, and the oxide semiconductor layer 11 using the photosensitive polyimide resin composition. .
The TFT substrate 20 illustrated in FIG. 2B includes a TFT having a bottom gate / top contact structure, and includes a gate electrode 13G formed on the adhesion layer 3 of the flexible substrate 10 and a gate electrode 13G. A gate insulating layer 14 formed using the photosensitive polyimide resin composition, an oxide semiconductor layer 11, a source electrode 12S and a drain electrode 12D formed on the gate insulating layer 14, and an oxide semiconductor A passivation layer 15 formed using the photosensitive polyimide resin composition is provided on the layer 11, the source electrode 12S, and the drain electrode 12D.

Further, as another example of the TFT substrate of the present invention, as illustrated in FIG. 3A, the TFT substrate 20 includes a TFT having a top gate type coplanar structure, and the adhesion layer 3 of the flexible substrate 10. Formed on the oxide semiconductor layer 11 formed above, the source electrode 12S and the drain electrode 12D formed on the oxide semiconductor layer 11, and the oxide semiconductor layer 11 using the photosensitive polyimide resin composition. And the gate electrode 13G formed on the gate insulating layer 14.
3B includes a TFT having a bottom gate type coplanar structure, and includes a gate electrode 13G formed on the adhesion layer 3 of the flexible substrate 10, and a gate electrode 13G. A gate insulating layer formed using the photosensitive polyimide resin composition; an oxide semiconductor layer formed on the gate insulating layer; and an oxide semiconductor layer formed on the oxide semiconductor layer. It has the source electrode 12S and the drain electrode 12D, and the passivation layer 15 formed on the oxide semiconductor layer 11 using the said photosensitive polyimide resin composition.
Further, the semiconductor layer contact insulating layer in the top gate type TFT illustrated in FIGS. 1 and 3A is a gate insulating layer, and the semiconductor layer in the bottom gate type TFT illustrated in FIGS. 2 and 3B. The contact insulating layers are a gate insulating layer and a passivation layer (FIG. 2). In this example, all of these semiconductor layer contact insulating layers are the photosensitive polyimide insulating layers.

According to the present invention, at least one of the semiconductor contact insulating layers included in the TFT is a photosensitive polyimide insulating layer formed using the photosensitive polyimide resin composition, that is, a photosensitive polyimide resin composition. By coating and patterning the photosensitive polyimide resin composition without performing a vapor deposition process using a vacuum facility required for forming an insulating layer made of an inorganic compound. Since an insulating layer can be formed by this, a simple process can be achieved.
In addition, the photosensitive polyimide insulating layer can be made into an insulating layer having excellent heat resistance because it contains polyimide, and when exposed to a high temperature atmosphere during the production of the oxide semiconductor layer and other members. Even if it exists, since it can be set as a thing with little fall of insulation performance, it can be set as the thing excellent in switching characteristics. Further, since it is made of resin, for example, even when a flexible substrate is used as the substrate and a flexible TFT substrate is used, the non-photosensitive polyimide insulating layer can be hardly cracked.
Furthermore, since the oxide semiconductor has excellent semiconductor characteristics among semiconductor materials, the TFT substrate of the present invention can have excellent semiconductor characteristics by using the oxide semiconductor layer.
Here, it is known that the semiconductor properties of the oxide semiconductor can be further improved by annealing in the presence of water (water vapor annealing) (Appl. Phys. Lett. 93, 192107 (2008) etc.).
On the other hand, when the photosensitive polyimide insulating layer is formed using a photosensitive polyimide resin composition containing a polyimide precursor as a polyimide component, it is necessary to imidize the polyimide precursor by a dehydration ring-closing reaction by annealing treatment. is there. Further, water is generated simultaneously with this imidization. When such an annealing treatment in the presence of water, that is, a water vapor annealing treatment is performed, the polyimide precursor can be imidized and at the same time the semiconductor characteristics of the oxide semiconductor can be improved, and the switching characteristics are superior. Because it can be. Therefore, the semiconductor characteristics of the oxide semiconductor layer can be improved without adding a separate water vapor annealing step.
Thus, by having both the said oxide semiconductor layer and the said photosensitive polyimide insulating layer, it can manufacture with a simple process especially and can be set as the thing excellent in the switching characteristic.

The TFT substrate of the present invention has at least a substrate and a TFT.
Hereinafter, each configuration of the TFT substrate of the present invention will be described in detail.

1. TFT
The TFT used in the present invention has at least the oxide semiconductor layer and the semiconductor contact insulating layer.

(1) Semiconductor layer contact insulation layer The semiconductor layer contact insulation layer used in the present invention is in contact with the oxide semiconductor layer, and at least one of them is the photosensitive polyimide insulation layer.

(A) Photosensitive polyimide insulating layer The photosensitive polyimide insulating layer used for this invention is formed using the photosensitive polyimide resin composition.

(I) Photosensitive polyimide resin composition The photosensitive polyimide resin composition used in the present invention is particularly limited as long as it can form a photosensitive polyimide insulating layer having a desired insulating property with high precision. However, examples include a) a polyimide component, b) a photosensitive component, c) a solvent, d) and the like.

  Specifically, a solvent development negative in which an ethylenic double bond is introduced into the above polyimide component as a photosensitive component into the carboxyl group of polyamic acid, which is a polyimide component, and further mixed with a photoradical initiator. Type photosensitive polyimide resin composition, an alkali development positive photosensitive polyimide resin composition in which a naphthoquinone diazide compound is added as a photosensitive component to a polyamic acid that is a polyimide component or a partially esterified product thereof, and an acid-crosslinking property that is a polyimide component. A negative photosensitive polyimide resin composition in which a photoacid generator is added as a photosensitive component to a polyimide or polyimide precursor into which a substituent is introduced, and a polyimide or polyimide precursor in which an acid-decomposable substituent that is a polyimide component is introduced To the body, a photoacid generator is added as a photosensitive component. Type photosensitive polyimide resin composition, an alkali developing negative photosensitive polyimide resin composition in which a photoacid generator is added as a photosensitive component to a polyamic acid that is a polyimide component, or a polyamic acid that is a polyimide component. An alkali developing negative photosensitive polyimide resin composition in which a nifedipine compound or the like is added as a component, and an alkali developing negative photosensitive polyimide resin composition in which a photobase generator is added as a photosensitive component to a polyamic acid that is a polyimide component Is mentioned.

The photosensitive polyimide resin composition used in the present invention preferably has a 5% weight loss temperature of 450 ° C. or higher.
Here, the photosensitive polyimide resin composition having a 5% weight reduction temperature of 450 ° C. or more is a weight reduction using a thermogravimetric analyzer for a polyimide film containing a polyimide resin after curing of the photosensitive polyimide resin composition. Is measured at a heating rate of 10 ° C./min up to 100 ° C. in a nitrogen atmosphere, heated at 100 ° C. for 60 minutes, allowed to cool in a nitrogen atmosphere for 15 minutes or more, and then heated up. The 5% weight loss temperature measured on the basis of the weight after cooling when measured at a rate of 10 ° C / min is 450 ° C or higher.
The 5% weight reduction temperature is the time when the weight of the sample is reduced by 5% from the initial weight when the weight reduction is measured using a thermogravimetric analyzer (that is, the sample weight becomes 95% of the initial weight). Temperature).

In the present invention, the 5% weight reduction temperature of the photosensitive polyimide resin composition is preferably 480 ° C. or higher, and more preferably 500 ° C. or higher. When the 5% weight reduction temperature is within the above range, the weight loss in a high temperature atmosphere or vacuum atmosphere when forming the oxide semiconductor layer or other member is small, that is, the outgas is small. This is because a TFT substrate having excellent switching characteristics can be obtained. In particular, since the oxide semiconductor layer is usually formed in a high temperature and vacuum atmosphere, when the oxide semiconductor layer is formed in an environment where a large amount of outgas can be generated, the outgas is used as an impurity. There is a high possibility that the oxide semiconductor layer is incorporated into the oxide semiconductor layer. On the other hand, when the photosensitive polyimide insulating layer is formed using the photosensitive polyimide resin composition having the above-mentioned 5% weight loss temperature, the photosensitive polyimide insulating layer can be used even in a high temperature and vacuum atmosphere. This is because the generation of the outgas is small and the oxide semiconductor layer can be reduced in the impurities.
Moreover, the outgas component contained in the photosensitive polyimide insulating layer formed using such a photosensitive polyimide resin composition usually increases significantly under general TFT manufacturing conditions and TFT usage environments. There is no. Therefore, the 5% weight reduction temperature of the photosensitive polyimide insulating layer is approximately the same as the 5% weight reduction temperature of the photosensitive polyimide resin composition.

a. Polyimide Component The polyimide component used in the present invention refers to a component that becomes a polyimide resin after curing (curing) in the photosensitive polyimide resin composition.
Specifically, a polyimide having a structure represented by the following formula (1) and a polyimide precursor having a structure represented by the following formulas (2) and (3) are exemplified.

As the polyimide component in the present invention, the above formula (1), formula (2) and formula (3) can be used even when only polymers having the structures of the above formula (1), formula (2) and formula (3) are used. Even if polymers having only the respective structures are mixed and used, those in which the structures of the above formulas (1), (2) and (3) are mixed in one polymer molecular chain can also be used.
In the present invention, the polyimide component preferably contains at least the polyimide precursor. This is because water is generated during the annealing process for imidization, so that the oxide semiconductor layer can be subjected to water vapor annealing at the same time as imidization, and semiconductor characteristics can be improved.
In the present invention, among them, the carboxyl group derived from an acid anhydride (or a derivative such as an esterified product thereof) is desirably 50% or more, more preferably 75% or more, and all of the following formulas ( The polyamic acid represented by 2) and derivatives thereof are preferable. This is because the above-described water vapor annealing can be effectively performed.
In addition, the polyamic acid (and the derivative thereof) of the formula (2) is particularly preferably a polyamic acid in which R ³ is all hydrogen atoms because of ease of synthesis and high solubility in an alkali developer. .
In addition, the content rate of the carboxyl group (or its ester) derived from an acid anhydride can be calculated | required by 100% -imidation rate (%). Therefore, when the carboxyl group (or its ester) derived from an acid anhydride is 50% of the whole, it indicates that the imidization ratio is 50%.
The imidization rate can be confirmed using, for example, an infrared absorption spectrum. Specifically, it can be determined by quantifying from the peak area of the C═O double bond derived from the imide bond contained in the polyimide resin.

(In the formulas (1) to (3), R ¹ is a tetravalent organic group, R ² is a divalent organic group, R ³ is a hydrogen atom or a monovalent organic group and R ¹ and R ² are repeated. And R ³ may be the same or different, and n is a natural number of 1 or more.)

  Moreover, about Formula (3), although it is left-right asymmetric, what differs in the left-right direction may be contained in one polymer molecular chain.

  In addition, like a solvent-developed negative photosensitive polyimide resin composition in which an ethylenic double bond is introduced into the carboxyl group of the polyamic acid with an ester bond and a photo radical initiator is further mixed, the carboxyl group of the polyamic acid is introduced through the carboxyl group of the polyamic acid. In the case of a compound having a photosensitive moiety introduced by covalent bond, C (= O) -O up to the carboxyl group of the polyamic acid is regarded as a polyimide component, and the substituent moiety containing the previously introduced photosensitive moiety is photosensitized. Considered a sexual component.

  In addition, in the solvent-developed negative photosensitive polyimide resin composition in which an ethylenic double bond is introduced into the carboxyl group of the polyamic acid by an ionic bond and a photo radical initiator is further mixed, the polyamic acid is used as a polyimide component, and the ionic bond The amine having an ethylenic double bond bonded by the above is a photosensitive component.

In the above formulas (1) to (3), generally R ¹ is a structure derived from tetracarboxylic dianhydride and R ² is a structure derived from diamine.

As a method for producing the polyimide component used in the present invention, a conventionally known method can be applied. For example, as a method for forming a polyimide precursor having the structure represented by (2) above, (i) a method of synthesizing polyamic acid from acid dianhydride and diamine, or (ii) monovalent to acid dianhydride Examples include, but are not limited to, a method in which a diamino compound or a derivative thereof is reacted with a carboxylic acid of an ester acid or an amic acid monomer synthesized by reacting an alcohol, an amino compound, an epoxy compound, or the like.
Moreover, as a formation method of the polyimide precursor which has the structure represented by said (3), or the polyimide represented by said (1), the method of imidating the polyimide precursor represented by said (2) by heating Is mentioned.

Examples of the tetracarboxylic dianhydride applicable to the polyimide component in the present invention include ethylene tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, cyclobutane tetracarboxylic dianhydride, and methylcyclobutane tetracarboxylic acid. Dianhydrides, aliphatic tetracarboxylic dianhydrides such as cyclopentanetetracarboxylic dianhydride; pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2, 2 ', 3,3'-benzophenone tetracarboxylic dianhydride, 2,3', 3,4'-benzophenone tetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,3 ′, 3,4′-biphenyltetracarboxylic dianhydride, , 2 ′, 6,6′-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) Propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane Dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1 , 1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride 1,3-bis [ (3,4-dicarboxy) benzoyl] benzene dianhydride, 1,4-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 2,2-bis {4- [4- (1, 2-dicarboxy) phenoxy] phenyl} propane dianhydride, 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, bis {4- [4- ( 1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, 4,4′-bis [4- ( 1,2-dicarboxy) phenoxy] biphenyl dianhydride, 4,4′-bis [3- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, bis {4- [4- (1,2- Dicarboxy) phenoxy] phenyl} Ton dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfone Anhydride, bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride Bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} -1 , 1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} -1,1,1,3 3,3-hexafluoropropane Water, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis (2,3- or 3,4-di Carboxyphenyl) propane dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetra Carboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic Acid dianhydride, pyridinetetracarboxylic dianhydride, sulfonyldiphthalic anhydride, m-terphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, p-terphenyl-3,3 ', 4,4'-tetracarboxylic acid Water, 9,9-bis- (trifluoromethyl) xanthenetetracarboxylic dianhydride, 9-phenyl-9- (trifluoromethyl) xanthenetetracarboxylic dianhydride, 12,14-diphenyl-12,14 -Bis (trifluoromethyl) -12H, 14H-5,7-dioxapentacene-2,3,9,10-tetracarboxylic dianhydride, 1,4-bis (3,4-dicarboxytrifluorophenoxy ) Tetrafluorobenzene dianhydride, 1,4-bis (trifluoromethyl) -2,3,5,6-benzenetetracarboxylic dianhydride, 1- (trifluoromethyl) -2,3,5,6 -Benzenetetracarboxylic dianhydride, p-phenylenebistrimellitic acid monoester dianhydride, p-biphenylenebistrimellitic acid monoester dianhydride, etc. Aromatic tetracarboxylic dianhydride, and the like.
These may be used alone or in combination of two or more.

On the other hand, a diamine component applicable to the polyimide component can also be used alone or in combination of two or more diamines. The diamine component used is p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′- Diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3, , 3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 2,2 -Di (3-aminophenyl) Propane, 2,2-di (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2,2-di (3-aminophenyl) -1,1, 1,3,3,3-hexafluoropropane, 2,2-di (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2- (3-aminophenyl) -2 -(4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,1-di (3-aminophenyl) -1-phenylethane, 1,1-di (4-amino) Phenyl) -1-phenylethane, 1- (3-aminophenyl) -1- (4-aminophenyl) -1-phenylethane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis ( 4-aminophenoxy) benzene, 1, -Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminobenzoyl) benzene, 1,3-bis (4-aminobenzoyl) benzene, , 4-bis (3-aminobenzoyl) benzene, 1,4-bis (4-aminobenzoyl) benzene, 1,3-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,3-bis ( 4-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (4-amino-α, α-dimethylbenzyl) benzene 1,3-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,3-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4- Bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 2,6-bis (3-aminophenoxy) benzo Nitrile, 2,6-bis (3-aminophenoxy) pyridine, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3- Aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-Aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-Aminophenoxy) phenyl] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4 -(4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [ 4- (4-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (4-aminophenoxy) benzo L] benzene, 1,3-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] Benzene, 1,4-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 4,4′-bis [4- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-Amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, 4,4′-bis [4- (4-aminophenoxy) phenoxy] diphenylsulfone, 3,3′-dia Mino-4,4′-diphenoxybenzophenone, 3,3′-diamino-4,4′-dibiphenoxybenzophenone, 3,3′-diamino-4-phenoxybenzophenone, 3,3′-diamino-4-biphenoxy Benzophenone, 6,6′-bis (3-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, 6,6′-bis (4-aminophenoxy) -3, Aromatic amines such as 3,3 ′, 3′-tetramethyl-1,1′-spirobiindane; 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,3-bis (4-aminobutyl) ) Tetramethyldisiloxane, α, ω-bis (3-aminopropyl) polydimethylsiloxane, α, ω-bis (3-aminobutyl) polydimethylsiloxane, bis (aminomethyl) A Bis (2-aminoethyl) ether, bis (3-aminopropyl) ether, bis (2-aminomethoxy) ethyl] ether, bis [2- (2-aminoethoxy) ethyl] ether, bis [2- ( 3-aminoprotoxy) ethyl] ether, 1,2-bis (aminomethoxy) ethane, 1,2-bis (2-aminoethoxy) ethane, 1,2-bis [2- (aminomethoxy) ethoxy] ethane, 1,2-bis [2- (2-aminoethoxy) ethoxy] ethane, ethylene glycol bis (3-aminopropyl) ether, diethylene glycol bis (3-aminopropyl) ether, triethylene glycol bis (3-aminopropyl) ether , Ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diamino Of 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane Such aliphatic amines; 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,2-di (2-aminoethyl) cyclohexane, 1,3-di (2-aminoethyl) ) Cyclohexane, 1,4-di (2-aminoethyl) cyclohexane, bis (4-aminocyclohexyl) methane, 2,6-bis (aminomethyl) bicyclo [2.2.1] heptane, 2,5- And alicyclic diamines such as bis (aminomethyl) bicyclo [2.2.1] heptane. Examples of guanamines include acetoguanamine, benzoguanamine, and the like, and some or all of the hydrogen atoms on the aromatic ring of the diamine are fluoro group, methyl group, methoxy group, trifluoromethyl group, or trifluoromethoxy group. Diamines substituted with substituents selected from the group can also be used.
Furthermore, depending on the purpose, any one or two or more of the ethynyl group, benzocyclobuten-4′-yl group, vinyl group, allyl group, cyano group, isocyanate group, and isopropenyl group serving as a crosslinking point, Even if it introduce | transduces into some or all of the hydrogen atoms on the aromatic ring of diamine as a substituent, it can be used.

As the photosensitive polyimide resin composition in the present invention, the 5% weight reduction temperature of the insulating layer is set within a predetermined range, and the 5% weight reduction temperature of the insulating layer is suitable for the TFT substrate of the present invention. The polyimide component preferably contains an aromatic skeleton. The polyimide resin obtained by heat-curing a polyimide component containing an aromatic skeleton is derived from its rigid and highly planar skeleton, and is excellent in heat resistance and insulation in a thin film, and has a 5% weight loss temperature. It is because it is preferably used for the insulating layer of the TFT substrate of the present invention because it is high and low outgas.
In addition, the polyimide component of the photosensitive polyimide resin composition having a high 5% weight loss temperature and low outgas has a portion derived from acid dianhydride having an aromatic structure, and a portion derived from diamine also has an aromatic structure. It is desirable to include. Therefore, the structure derived from the diamine component is also preferably a structure derived from an aromatic diamine. In particular, it is preferable that all of the part derived from the acid dianhydride and the part derived from the diamine are a wholly aromatic polyimide or a wholly aromatic polyimide precursor containing an aromatic structure.

Here, the wholly aromatic polyimide precursor is a polyimide precursor obtained by copolymerization of an aromatic acid component and an aromatic amine component, or polymerization of an aromatic acid / amino component, and a derivative thereof. The aromatic acid component is a compound in which all four acid groups forming the polyimide skeleton are substituted on the aromatic ring, and the aromatic amine component is the two amino groups forming the polyimide skeleton. Both are compounds substituted on the aromatic ring, and the aromatic acid / amino component is a compound in which both the acid group and amino group forming the polyimide skeleton are substituted on the aromatic ring. However, as is clear from the specific examples of the raw material aromatic dianhydride and aromatic diamine, it is not necessary that all acid groups or amino groups exist on the same aromatic ring.
For the above reasons, the polyimide precursor should have a copolymerization ratio of the aromatic acid component and / or aromatic amine component as large as possible when the final polyimide resin is required to have heat resistance and dimensional stability. preferable. Specifically, the proportion of the aromatic acid component in the acid component constituting the repeating unit of the imide structure is preferably 50 mol% or more, particularly preferably 70 mol% or more, and the amine component constituting the repeating unit of the imide structure The proportion of the aromatic amine component in the total is preferably 40 mol% or more, particularly preferably 60 mol% or more, and is preferably a wholly aromatic polyimide or a wholly aromatic polyimide precursor.

In the present invention, among them, 33 mol% or more of R ^{1 in} the polyimide component having the structure represented by the above (1) to (3) is preferably any structure represented by the following formula. . It is because it has the merit that it becomes a polyimide resin which is excellent in heat resistance and shows a low linear thermal expansion coefficient.

(In formula (11), a is a natural number of 0 or 1 or more, A is a single bond (biphenyl structure), an oxygen atom (ether bond), or an ester bond. The linking group is bonded to the 2, 3 or 3, 4 position of the aromatic ring as viewed from the bonding site of the aromatic ring.)

  In the present invention, in particular, when the polyimide component having the structure represented by the above (1) to (3) includes the structure represented by the above formula (11), the polyimide resin exhibits low hygroscopic expansion. Furthermore, there is also an advantage that it is easily available on the market and is low cost.

The polyimide component having the above-described structure can form a polyimide resin exhibiting high heat resistance and a low linear thermal expansion coefficient. Therefore, the content of the structure represented by the above formula is preferably closer to 100 mol% in R ^{1 in} the above formulas (1) to (3), but at least in the above formulas (1) to (3). it may be contained 33% or more of R ^1. Among them, the content of the structure represented by the above formula is preferably 50 mol% or more, more preferably 70 mol% or more, among R ^{1 in} the above formulas (1) to (3).

  In the present invention, examples of the structure of the acid dianhydride that makes the polyimide resin moisture-absorbing include those represented by the following formula (12).

(In formula (12), a is a natural number of 0 or 1 or more, A is a single bond (biphenyl structure), an oxygen atom (ether bond), or an ester bond. (The acid anhydride skeleton (—CO—O—CO—) is bonded to the 2, 3 or 3, 4 position of the aromatic ring as viewed from the bonding site of the adjacent aromatic ring.)

  In the above formula (12), as the acid dianhydride in which A is a single bond (biphenyl structure) or an oxygen atom (ether bond), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2 , 3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, etc. Is mentioned. These are preferable from the viewpoint of reducing the hygroscopic expansion coefficient and from the viewpoint of expanding the selectivity of the diamine.

  In the above formula (12), a phenyl ester acid dianhydride in which A is an ester bond is particularly preferable from the viewpoint of making the polyimide resin moisture-absorbing. For example, an acid dianhydride represented by the following formula may be mentioned. Specific examples include p-phenylenebistrimellitic acid monoester dianhydride, p-biphenylenebistrimellitic acid monoester dianhydride, and the like. These are particularly preferable from the viewpoint of reducing the hygroscopic expansion coefficient and from the viewpoint of expanding the selectivity of the diamine.

(Wherein, a is a natural number of 0 or 1 or more. The acid anhydride skeleton (—CO—O—CO—) is a 2, 3-position or 3 of the aromatic ring as viewed from the bonding site of the adjacent aromatic ring. , Binds to position 4.)

  In the case of the tetracarboxylic dianhydride having a small hygroscopic expansion coefficient as described above, a wide variety of diamines to be described later can be selected.

  As the tetracarboxylic dianhydride used in combination, a tetracarboxylic dianhydride having at least one fluorine atom as represented by the following formula can be used. When tetracarboxylic dianhydride into which fluorine is introduced is used, the hygroscopic expansion coefficient of the finally obtained polyimide resin is lowered. The tetracarboxylic dianhydride having at least one fluorine atom preferably has a fluoro group, a trifluoromethyl group, or a trifluoromethoxy group. Specific examples include 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride. However, when the polyimide precursor contained as the polyimide component has a skeleton containing fluorine, the polyimide precursor tends to be difficult to dissolve in a basic aqueous solution, and a resist or the like is used in the state of the polyimide precursor. When patterning is performed, it may be necessary to perform development with a mixed solution of an organic solvent such as alcohol and a basic aqueous solution.

  Here, the selected diamine is preferably an aromatic diamine from the viewpoint of heat resistance, that is, low outgassing, but in a range not exceeding 60 mol%, preferably 40 mol% of the total of the diamine depending on the desired physical properties. A non-aromatic diamine such as an aliphatic diamine or a siloxane diamine may be used.

Moreover, in the said polyimide component, it is preferable that 33 mol% or more among R < ² > in said Formula (1)-(3) is either structure represented by a following formula.

(R ¹¹ is a divalent organic group, an oxygen atom, a sulfur atom, or a sulfone group, and R ¹² and R ¹³ are a monovalent organic group or a halogen atom.)

When the polyimide component contains any structure of the above formula, it is derived from these rigid skeletons and exhibits low linear thermal expansion and low hygroscopic expansion. Furthermore, there is also an advantage that it is easily available on the market and is low cost.
When it has the above structure, the heat resistance of the polyimide resin is improved and the linear thermal expansion coefficient is reduced. Therefore, the closer to 100 mol% of R ^{2 in} the above formulas (1) to (3), the better, but it is preferable that at least 33% or more of R ^{2 in} the above formulas (1) to (3) is contained. Good. Among them, the content of the structure represented by the above formula is preferably 50 mol% or more, more preferably 70 mol% or more, of R ^{2 in} the above formula (1).

  From the viewpoint of lowering the hygroscopic expansion of the polyimide resin, the diamine structure is preferably represented by the following formulas (13) and (14).

(In formula (13), two amino groups may be bonded to the same aromatic ring.
In Formula (14), a is a natural number of 0 or 1 or more, and the amino group is bonded to the meta position or the para position with respect to the bond between the benzene rings. Further, some or all of the hydrogen atoms on the aromatic ring may be substituted with a substituent selected from a fluoro group, a methyl group, a methoxy group, a trifluoromethyl group, or a trifluoromethoxy group. )

  Specific examples of the diamine represented by the above formula (13) include p-phenylenediamine, m-phenylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2 , 7-diaminonaphthalene, 1,4-diaminoanthracene and the like.

  Specific examples of the diamine represented by the above formula (14) include 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 3 3,3′-dichloro-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, and the like.

  In addition, when fluorine is introduced as a substituent of the aromatic ring, the hygroscopic expansion coefficient of the polyimide resin can be reduced. For example, examples of the structure in which fluorine is introduced in the diamine represented by the above formula (14) include those represented by the following formula. However, a polyimide precursor containing fluorine, particularly polyamic acid, is difficult to dissolve in a basic aqueous solution. When a photosensitive polyimide insulating layer is partially formed on a substrate, an alcohol is used during the processing of the insulating layer. It may be necessary to develop with a mixed solution with an organic solvent such as

  The polyimide component used in the present invention increases the sensitivity when the photosensitive polyimide resin composition is used, and in order to obtain a pattern shape that accurately reproduces the mask pattern, with respect to the exposure wavelength when the film thickness is 1 μm. Therefore, it is preferable to exhibit a transmittance of at least 5%, more preferably a transmittance of 15% or more.

In addition, when exposure is performed using a high-pressure mercury lamp, which is a general exposure light source, a transmittance with respect to an electromagnetic wave having a wavelength of at least 436 nm, 405 nm, and 365 nm is formed on a film having a thickness of 1 μm. Is preferably 5% or more, more preferably 15%, and still more preferably 50% or more.
That the transmittance | permeability of a polyimide component is high with respect to an exposure wavelength means that there is little light loss, and a highly sensitive photosensitive polyimide resin composition can be obtained.

In order to increase the transmittance as the polyimide component, it is desirable to use an acid dianhydride into which fluorine is introduced as an acid dianhydride or an acid dianhydride having an alicyclic skeleton. However, if an acid dianhydride having an alicyclic skeleton is used, the heat resistance may be lowered and the low outgassing property may be impaired.
In the present invention, in order to increase the transmittance, the use of an aromatic acid dianhydride into which fluorine is introduced as the acid dianhydride reduces the hygroscopic expansion while maintaining heat resistance (because it is aromatic). It is further preferable because it can be performed.

As the tetracarboxylic dianhydride having at least one fluorine atom used in the present invention, the above-mentioned tetracarboxylic dianhydride having a fluorine atom can be used, among which a fluoro group, a trifluoromethyl group, Alternatively, it preferably has a trifluoromethoxy group. Specific examples include 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride.
However, a polyimide precursor having a skeleton containing fluorine tends to be difficult to dissolve in a basic aqueous solution, and when patterning using a resist or the like in the state of the polyimide precursor, an organic solvent such as alcohol and the like It may be necessary to perform development with a mixed solution with a basic aqueous solution.

  Also, rigid acid dianhydrides such as pyromellitic acid anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, etc. If used, the linear thermal expansion coefficient of the finally obtained polyimide resin is reduced, but it tends to hinder the improvement of transparency, so it may be used in combination while paying attention to the copolymerization ratio.

In order to increase the transmittance as the polyimide component, it is desirable to use a diamine introduced with fluorine as a diamine or a diamine having an alicyclic skeleton. However, if a diamine having an alicyclic skeleton is used, the heat resistance may be lowered and the low outgassing property may be impaired.
In order to increase the transmittance, it is more preferable to use an aromatic diamine into which fluorine is introduced as the diamine because it is possible to reduce hygroscopic expansion while maintaining heat resistance (since it is aromatic).

Specific examples of the aromatic diamine into which fluorine has been introduced include those having the above-mentioned structure into which fluorine has been introduced. More specifically, 2,2′-ditrifluoromethyl-4 , 4'-diaminobiphenyl, 2,2-di (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-di (4-aminophenyl) -1,1 , 1,3,3,3-hexafluoropropane, 2- (3-aminophenyl) -2- (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,3 -Bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,3-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (3-amino-α , Α-Ditrifluoromethylbenzyl Benzene, 1,4-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3 Examples include 3-hexafluoropropane and 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane.
However, a polyimide precursor containing fluorine, particularly polyamic acid, is difficult to dissolve in a basic aqueous solution. When a photosensitive polyimide insulating layer is partially formed on a substrate, an alcohol is used during the processing of the insulating layer. It may be necessary to develop with a mixed solution with an organic solvent such as

Moreover, the ratio of the ring structure after imidation contained in the above formulas (1) and (3) is the carboxylic acid before imidation contained in the polyimide precursor represented by the above formulas (3) and (2), respectively. Since the transmittance tends to be lower than that of the portion, it is desirable to use a highly transparent polyimide precursor containing a large number of structures before imidization. It is desirable that the acid anhydride-derived carboxyl group (or ester thereof) is 50% or more of the total, more preferably 75% or more, and all of the polyimide precursor represented by the above formula (2), that is, polyamic Acid (and) derivatives thereof are preferred.
Moreover, when developing using an alkali developing solution, the solubility with respect to an alkali developing solution can be changed with the residual amount of the carboxylic acid part before imidation contained in said Formula (2) and (3). From the viewpoint of increasing the development speed, it is desirable to use a highly soluble polyimide precursor containing a large number of structures before imidization, and R ³ in the above formulas (2) and (3) are all hydrogen atoms. It is preferable that However, when the development speed is too high and the solubility of the pattern remaining portion is too high, the one that has undergone imidization is used, or a monovalent organic group is added to R ³ in (2) and (3) above. It can be introduced to lower the dissolution rate.

  On the other hand, when a diamine having a siloxane skeleton such as 1,3-bis (3-aminopropyl) tetramethyldisiloxane is used as the diamine, the adhesion to the substrate is improved or the elastic modulus of the polyimide resin is decreased. The glass transition temperature can be lowered.

The weight average molecular weight of the polyimide component used in the present invention is preferably in the range of 3,000 to 1,000,000, and more preferably in the range of 5,000 to 500,000, depending on the use. More preferably, it is in the range of 10,000 to 500,000. When the weight average molecular weight is less than 3,000, it is difficult to obtain sufficient strength when a coating film or film is used. In addition, the strength of the film is reduced when a heat treatment or the like is performed to obtain a polymer such as a polyimide resin. On the other hand, when the weight average molecular weight exceeds 1,000,000, the viscosity increases and the solubility decreases, so that it is difficult to obtain a coating film or film having a smooth surface and a uniform film thickness.
The molecular weight used here refers to a value in terms of polystyrene by gel permeation chromatography (GPC), may be the molecular weight of the polyimide precursor itself, or after chemical imidization treatment with acetic anhydride or the like. Things can be used.

As content of the polyimide component used for this invention, it is 50 weight% or more with respect to the whole solid of the said photosensitive polyimide resin composition from the point of the film | membrane physical property of the pattern obtained, especially film | membrane intensity | strength and heat resistance. In particular, it is preferably 70% by weight or more.
In addition, solid content of the photosensitive polyimide resin composition is all components other than a solvent, and a liquid monomer component is also contained in solid content.

b. Photosensitive Component The photosensitive component in the present invention is included for curing the polyimide component, and includes a photo radical generator, a photo acid generator, and a photo base generator contained in the above-described photosensitive polyimide resin composition. A photoinitiator such as naphthoquinonediazide compound, an ethylenic double compound introduced into the carboxyl group of polyamic acid with an ester bond or ionic bond, along with components that change the solubility of the compound itself upon light irradiation. Components that crosslink by radicals, such as bonding sites, radically crosslinkable monomers, acid crosslinkable monomers, photosensitive main components such as acid-decomposable substituents introduced into the carboxyl group of polyamic acid, Examples include photosensitive auxiliary components such as sensitizers used together with such photosensitive main components.

  More specifically, in a solvent-developed negative photosensitive polyimide resin composition in which an ethylenic double bond is introduced into a carboxyl group of a polyamic acid by an ester bond or an ionic bond, and a photo radical initiator is further mixed, In the alkali development positive photosensitive polyimide resin composition in which a naphthoquinone diazide compound is added to a binding site and a photo radical generator, polyamic acid or a partially esterified product thereof, a naphthoquinone diazide compound, a polyimide or a polyimide having an acid-crosslinking substituent introduced In a negative photosensitive polyimide resin composition in which a photoacid generator is added to the precursor, a photoacid generator is added to the photoacid generator and a polyimide or polyimide precursor having an acid-decomposable substituent and an acid-decomposable substituent. In a positive photosensitive polyimide resin composition to which a generator is added, a photoacid generator and In the alkali developing negative photosensitive polyimide resin composition in which a photoacid generator is added to a degradable substituent or polyamic acid, a photoacid generator is used, or an alkali developing negative type in which a polyamic acid is added with a nifedipine compound or the like In the photosensitive polyimide resin composition, the nifedipine-based compound and in the alkali development negative photosensitive polyimide resin composition obtained by adding a photobase generator to polyamic acid, the photobase generator corresponds to the photosensitive component.

The content of the photosensitive component used in the present invention is not particularly limited as long as it can form a photosensitive polyimide insulating layer having a desired pattern, and can be a general content.
Polyimide resin is generally known as a high heat-resistant resin, and since it has high heat resistance, the photosensitive component tends to have lower heat resistance than the polyimide component. If the proportion of the component is reduced, the outgassing property is reduced.
Therefore, the content of the photosensitive component is preferably small. In the present invention, the photosensitive component is 0.1 parts by weight or more and less than 30 parts by weight with respect to 100 parts by weight of the polyimide component. It is preferably within the range, and in particular, it is preferably within the range of 0.5 to 20 parts by weight, and particularly preferably within the range of 0.5 to 15 parts by weight.

Among the photosensitive components used in the present invention, those having a photoacid generator or a photobase generator as a main component are preferable. The photoacid generator or photobase generator is preferably used because the generated chemical species act catalytically, and the content of additives other than the polyimide component and solvent, which are constituent components of the polyimide resin, can be reduced. Because you can.
In particular, a photoacid generator or photobase generator is added to a polyimide precursor such as polyamic acid, and the imidation reaction is promoted catalytically by the acid or base generated during light irradiation to selectively insolubilize the exposed area. In this system, patterning is possible by adding only a photoacid generator or a photobase generator. This is because it is not necessary to introduce a crosslinking component or a degradable substituent, and therefore the amount of additive can be further reduced.
Therefore, the content of the photosensitive component contained in a general photosensitive polyimide resin composition is more than 30 parts by weight with respect to 100 parts by weight of the polyimide component, whereas the acid This is because the generator or photobase generator has exposure sensitivity that can be sufficiently cured even when the content is within the above-mentioned range, because the generated chemical species act catalytically as described above. . Moreover, since the said photosensitive component has low heat resistance compared with a polyimide component and it is thought that it is a main component of outgas, by making the said content into the range mentioned above, the said photosensitive polyimide insulating layer of This is because the weight can be reduced little, that is, the amount of outgas generation can be made sufficiently small.
In the present invention, it is particularly preferable that the photosensitive component is mainly composed of the photobase generator, and in particular, it is the photobase generator, that is, the photosensitive component is the above. It is preferable that only a photobase generator is included. The base which is a generated chemical species is desirable because it has less influence on metals and the like than acids.
In addition, the main component means that the content of the photobase generator and the like in the photosensitive component is 50% by mass or more.

The photobase generator used in the present invention is not active under normal conditions of normal temperature and pressure, but generates a base (basic substance) when subjected to electromagnetic wave irradiation and heating as an external stimulus. If it is, it will not specifically limit.
In the present invention, unless otherwise specified, the electromagnetic wave is not only an electromagnetic wave having a wavelength in the visible and invisible regions, but also a particle beam such as an electron beam, and radiation or a general term for the electromagnetic wave and the particle beam. Contains ionizing radiation. In this specification, irradiation with electromagnetic waves is also referred to as exposure.

  In the present invention, known photobase generators can be used. For example, M. Shirai, and M Tsunooka, Prog. Polym. Sci., 21, 1 (1996), Masahiro Tsunooka, Polymer Processing, 46, 2 (1997), C. Kutal, Coord. Chem. Rev. , 211, 353 (2001), Y. Kaneko, A. Sarker, and D. Neckers, Chem. Mater., 11, 170 (1999), H. Tachi, M. Shirai, and M. Tsunooka, J. Photopolym. Sci. Technol., 13, 153 (2000), M. Winkle, and K. Graziano, J. Photopolym. Sci. Technol., 3, 419 (1990), M. Tsunooka, H. Tachi, and S. Yoshitaka, Transition as described in J. Photopolym. Sci. Technol., 9, 13 (1996), K. Suyama, H. Araki, M. Shirai, J. Photopolym. Sci. Technol., 19, 81 (2006) An ionic compound neutralized by forming a salt with a base component, such as a metal compound complex, an ammonium salt or the like, or an amidine moiety formed by forming a salt with a carboxylic acid. And urethane bonds and oximes such as carbamate derivatives, oxime ester derivatives and acyl compounds. Etc. By mention may be made of non-ionic, which is latent focus.

  Here, specific examples of the ionic compound as the photobase generator include compounds represented by the following formulae.

  Moreover, as an oxime ester derivative as a photobase generator, the compound shown by a following formula can be mentioned, for example.

  Examples of the acyl compound include compounds represented by the following formula.

  Examples of the carbamate compound as the photobase generator include compounds represented by the following formula.

  Moreover, as a photobase generator, the compounds as shown below are mentioned, for example.

(In Formula (a), R ²¹ and R ²² are each independently hydrogen or a monovalent organic group, and may be the same or different. R ²¹ and R ²² are bonded to each other. May form a cyclic structure and may contain a heteroatom bond, provided that at least one of R ²¹ and R ²² is a monovalent organic group R ²³ , R ²⁴ , R ²⁵ And R ²⁶ are each independently hydrogen, halogen, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group. , A phosphonate group, an amino group, an ammonio group, or a monovalent organic group, which may be the same or different, and R ²³ , R ²⁴ , R ²⁵ and R ²⁶ , two or more of which are bonded A ring structure may be formed, and a heteroatom bond may be included.)

Since the photobase generator represented by the above formula (a) has the specific structure as described above, (—CH═CH—C () in the above formula (a) is irradiated by irradiation with light such as ultraviolet rays. The ═O)-) moiety isomerizes to the cis isomer and is further cyclized by heating to produce the base (NHR ²¹ R ²² ). That is, the photobase generator represented by the above formula (a) can generate a primary amine, a secondary amine, or an amidine-based compound as a base according to the structure.

  The above-mentioned photobase generators can be used singly or in combination of a plurality of types.

  The photobase generator used in the present invention is used in combination with the above polyimide component. Since the polyimide component has strong absorption in the wavelength region of less than 350 nm, both the polyimide and the polyimide precursor, it is desirable that the photobase generator has sensitivity in the wavelength region of 350 nm or more. In order to sufficiently exhibit the function of generating a base for the polyimide component to become a final product, it is necessary to have absorption for at least a part of the exposure wavelength. The wavelength of a high-pressure mercury lamp that is a general exposure light source includes 365 nm, 405 nm, and 436 nm. For this reason, it is preferable that the base generator in the present invention absorbs electromagnetic waves having at least one wavelength among electromagnetic waves having wavelengths of at least 365 nm, 405 nm, and 436 nm. In such a case, it is preferable because the number of applicable polyimide components is further increased.

  Examples of the basic substance generated in the photobase generator according to the present invention include an amine represented by the following formula A and an amidine represented by the following formula B.

(R ^{c s} are each independently hydrogen or a monovalent organic group, and may be the same or different. R ^c may be bonded to form a cyclic structure. Provided that at least one of R ^c is a monovalent organic group, and each R ^d is independently hydrogen or a monovalent organic group, and R ^d may be bonded to form a cyclic structure or may contain a hetero atom bond.)

In addition, when R ^c of the formula (A) has an amidine structure as contained in the formula (B), the generated base is not the amine of the formula (A) but the formula (B ) Belonging to amidine.

  In view of the large effect of the generated basic substance such as the catalytic effect as described above, it is preferable that the generated basic substance is an aliphatic amine or amidine because it is a highly basic amine. Among these, from the viewpoint of basicity, secondary or tertiary aliphatic amines or amidines are preferable. However, even when an aliphatic primary amine is used, a sufficient catalytic effect can be obtained as compared with the case where an aromatic amine is used. Therefore, among aliphatic amines, from the viewpoints of thermal properties such as 5% weight loss temperature, 50% weight loss temperature, thermal decomposition temperature, other physical properties such as solubility, ease of synthesis and cost, etc. It is desirable to appropriately select amidine.

In the present invention, the aliphatic amine is generated to achieve high sensitivity, and further, from the viewpoint of increasing the solubility contrast of the unexposed area of the exposed portion, directly with the nitrogen atom of R ^c in the formula (A). It is preferable that all bonded atoms are hydrogen atoms or carbon atoms having SP3 orbital (except when all of R ^c are hydrogen atoms).
Examples of the substituent in which the atom directly bonded to the nitrogen atom is a carbon atom having an SP3 orbital include a linear aliphatic hydrocarbon group, a branched aliphatic hydrocarbon group, and a cyclic aliphatic hydrocarbon. An aliphatic hydrocarbon group composed of a group or a combination thereof. In addition, the said aliphatic hydrocarbon group may have substituents, such as an aromatic group, or may contain bonds other than hydrocarbons, such as a hetero atom, in a hydrocarbon chain. Preferable examples include a linear or branched saturated or unsaturated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 4 to 13 carbon atoms, a phenoxyalkyl group having 7 to 26 carbon atoms, and an aryl having 7 to 26 carbon atoms. An alkyl group and a C1-C20 hydroxyalkyl group are mentioned.
Here, when R ^c has the above cyclic aliphatic hydrocarbon group or the above cycloalkyl group, a heterocyclic structure containing a nitrogen atom to which two of R ^c are linked to form a ring and R ^c is bonded Including the case of forming.

Specific examples of the aliphatic hydrocarbon group include a methyl group, an ethyl group, an ethynyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a cyclohexyl group, an isobornyl group, a norbornyl group, and an adamantyl group. , A benzyl group and the like, but are not limited thereto.
Further, it becomes annularly two of R ^c linked, the heterocyclic structure when forming a heterocyclic structure containing a nitrogen atom to which R ^c is attached, for example, aziridine (three-membered ring) Azetidine (4-membered ring), pyrrolidine (5-membered ring), piperidine (6-membered ring), azepane (7-membered ring), azocane (8-membered ring) and the like. These heterocyclic structures may have a substituent such as a linear or branched alkyl group. For example, as an alkyl substituent, a monoalkylaziridine such as methylaziridine, a dialkylaziridine such as dimethylaziridine, and methylazetidine Monoalkyl azetidine such as dialkyl azetidine such as dimethyl azetidine, trialkyl azetidine such as trimethyl azetidine, monoalkyl pyrrolidine such as methyl pyrrolidine, dialkyl pyrrolidine such as dimethyl pyrrolidine, trialkyl pyrrolidine such as trimethyl pyrrolidine, tetra Tetraalkylpyrrolidines such as methylpyrrolidine, monoalkylpiperidines such as methylpiperidine, dialkylpiperidines such as dimethylpiperidine, and trialkylpiperidines such as trimethylpiperidine Lysine, a tetraalkyl piperidine, such as tetramethylpiperidine, penta-alkyl piperidines such as such as pentamethyl piperidine.

In the present invention, the bond other than the hydrocarbon atom group in the organic group of R ^c is not particularly limited as long as the effect of the present invention is not impaired, and an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, Ester bond, amide bond, urethane bond, imino bond (-N = C (-R)-, -C (= NR)-, where R is a hydrogen atom or a monovalent organic group), carbonate bond, sulfonyl bond, Examples thereof include a sulfinyl bond and an azo bond. From the viewpoint of heat resistance, the bond other than the hydrocarbon atom group in the organic group includes an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, a urethane bond, and an imino bond (—N═C ( -R)-, -C (= NR)-: where R is a hydrogen atom or a monovalent organic group), a carbonate bond, a sulfonyl bond, or a sulfinyl bond.

In the present invention, the substituent other than the hydrocarbon atom group in the organic group of R ^c is not particularly limited as long as the effect of the present invention is not impaired, and is a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group. Group, isocyano group, cyanato group, isocyanato group, thiocyanato group, isothiocyanato group, silyl group, silanol group, alkoxy group, alkoxycarbonyl group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxyl group, carboxylate group, Acyl group, acyloxy group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, hydroxyimino group, saturated or unsaturated alkyl ether group, saturated or unsaturated alkyl thioether group, aryl ether group And arylthioates Ether group, an amino group _{(-NH 2, -NHR, -NRR '} : wherein, R and R' each independently represent a hydrocarbon atom group). The hydrogen atom contained in the substituent may be substituted with a hydrocarbon atom group. Moreover, the hydrocarbon atom group contained in the substituent may be linear, branched, or cyclic.

  Specific examples of amines generated during the decomposition of the photobase generator according to the present invention include primary amines such as n-butylamine, amylamine, hexylamine, cyclohexylamine, octylamine, and benzylamine, diethylamine, and diamine. Linear secondary amines such as propylamine, diisopropylamine and dibutylamine, secondary amines such as aziridine, azetidine, pyrrolidine, piperidine, azepane and azocan, and secondary amines such as alkyl substitutions thereof , Aromatic tertiary amines such as dimethylaniline, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, 1,4-diazabicyclo [2.2.2] octane, quinuclidine and 3-quinuclidinol Tribe Tertiary amines, and isoquinoline, pyridine, collidine, and heterocyclic tertiary amines such as beta-picoline and the like.

  Specific examples of the amidine generated upon decomposition of the photobase generator according to the present invention include secondary amidines such as imidazole, purine, triazole, guanidine, and derivatives thereof, pyrimidine, triazine, 1,8-diazabicyclo [5.4. .0] tertiary amidines such as undeca-7-ene (DBU) and 1,5-diazabicyclo [4.3.0] non-5-ene (DBN), and derivatives thereof.

  The photobase generator in the present invention preferably has a temperature (5% weight reduction temperature) of 150 ° C. or higher when heated to 5% by weight from the initial weight and is preferably 200 ° C. or higher. . In the case of forming a low outgas photosensitive polyimide insulating layer using a low outgas photosensitive polyimide resin composition containing a photobase generator as a photosensitive component, the heating step performed after exposure and before development is usually 150 to 200 ° C. Therefore, it is preferable because the photobase generator in the unexposed area is hardly decomposed. Further, in the case of a polyimide precursor or polyimide, it is necessary to use a high boiling point solvent such as N-methyl-2-pyrrolidone when forming a coating film. The coating film can be formed under drying conditions that reduce the influence of the solvent. Thereby, the reduction | decrease of the solubility contrast by the influence of a residual solvent in an exposed part and an unexposed part can be suppressed.

On the other hand, since it is preferable that the impurities derived from the base generator do not remain in the photosensitive polyimide insulating layer in the present invention, the base generator in the present invention has a heating process (for example, a polymer to be combined) performed after development. In the case of a polyimide precursor, it is preferably decomposed or volatilized in the imidization process). Specifically, the 5% weight loss temperature of the base generator in the present invention is preferably 300 ° C. or less, more preferably 280 ° C. or less, and particularly preferably 260 ° C. or less.
In the present invention, the 25% weight reduction temperature is preferably 300 ° C. or less, and in particular, the 50% weight reduction temperature is preferably 300 ° C. or less.
Furthermore, in the present invention, the weight reduction rate at 300 ° C. is preferably 50% or more, and more preferably 70% or more, and particularly preferably 85% or more.

  In the present invention, among the above base generators, those represented by the above formula (a) are preferable. Even if it is exposed to a high temperature atmosphere or a vacuum atmosphere in a subsequent process such as forming an oxide semiconductor layer because it is easily decomposed or volatilized in a heating process performed after development, It is because it can be made into the thing with few components which volatilize and become outgas. This is because the resulting low outgas polyimide insulating layer can be reduced in outgas.

The base generator represented by the above formula (a) can efficiently generate a base with a small amount of electromagnetic wave irradiation by combining electromagnetic wave irradiation and heating. Higher sensitivity than
Since the base generator represented by the above formula (a) has the above-mentioned specific structure, as shown by the following formula, (—CH═CH—C) in the formula (a) when irradiated with electromagnetic waves. The (= O)-) moiety is isomerized to the cis isomer and further cyclized by heating to produce the base (NHR ²¹ R ²² ). By the catalytic action of the amine, the temperature at which the reaction when the polyimide component becomes the final product can be lowered, or the curing reaction where the polyimide component becomes the final product can be started.
The base generator represented by the above formula (a) generates a base even when irradiated with an electromagnetic wave, but generation of the base is promoted by heating appropriately.

  When the base generator represented by the chemical formula (a) is cyclized, the phenolic hydroxyl group disappears, the solubility changes, and in the case of a basic aqueous solution, the solubility decreases. Thereby, it has a function of further assisting the decrease in solubility due to the reaction of the polyimide component to the final product, and the solubility contrast between the exposed portion and the unexposed portion can be increased.

R ²¹ and R ²² are each independently a hydrogen atom or a monovalent organic group, and at least one of R ²¹ and R ²² is a monovalent organic group. ^{Further, NHR} 21 ^{R 22} is a base (basic ^{substance), R 21} and ^{R 22,} respectively, is preferably an organic group containing no amino group. If an amino group is contained in R ²¹ and R ²² , the base generator itself becomes a basic substance, which accelerates the reaction of the polyimide component, resulting in a difference in solubility contrast between the exposed and unexposed areas. May become smaller. However, when there is a difference in basicity between the irradiation with electromagnetic waves and the base generated after heating, such as when an amino group is bonded to the aromatic ring present in the organic group of R ²¹ and R ^22. May be used even if the organic group of R ²¹ and R ²² contains an amino group.
Examples of the monovalent organic group include a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, an aryl group, an aralkyl group, and a saturated or unsaturated halogenated alkyl group. These organic groups may contain bonds and substituents other than hydrocarbon groups such as heteroatoms in the organic group, and these may be linear or branched.

R ²¹ and R ²² may be bonded to form a cyclic structure.
The cyclic structure is a combination of two or more selected from the group consisting of saturated or unsaturated alicyclic hydrocarbons, heterocycles, and condensed rings, and the alicyclic hydrocarbons, heterocycles, and condensed rings. The structure which becomes may be sufficient.

The bond other than the hydrocarbon group in the organic group of R ²¹ and R ²² is not particularly limited as long as the effect of the present invention is not impaired. , Amide bond, urethane bond, imino bond (—N═C (—R) —, —C (═NR) —, where R is a hydrogen atom or a monovalent organic group), carbonate bond, sulfonyl bond, sulfinyl bond And an azo bond.
From the viewpoint of heat resistance, the bond other than the hydrocarbon group in the organic group includes an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, a urethane bond, and an imino bond (—N═C (— R)-, -C (= NR)-: where R is a hydrogen atom or a monovalent organic group), a carbonate bond, a sulfonyl bond, or a sulfinyl bond.

The substituent other than the hydrocarbon group in the organic group of R ²¹ and R ²² is not particularly limited as long as the effect of the present invention is not impaired. A halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group, Isocyano group, cyanato group, isocyanato group, thiocyanato group, isothiocyanato group, silyl group, silanol group, alkoxy group, alkoxycarbonyl group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxyl group, carboxylate group, acyl group Acyloxy group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, hydroxyimino group, saturated or unsaturated alkyl ether group, saturated or unsaturated alkyl thioether group, aryl ether group, and Arylthioether group Amino group _{(-NH 2, -NHR, -NRR '} : wherein, R and R' are each independently a hydrocarbon group) include an ammonio group. The hydrogen contained in the substituent may be substituted with a hydrocarbon group. Further, the hydrocarbon group contained in the substituent may be any of linear, branched, and cyclic.
Examples of the substituent other than the hydrocarbon group in the organic group of R ²¹ and R ²² include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group, an isocyano group, a cyanato group, an isocyanato group, a thiocyanato group, an isothiocyanato group, Silyl group, silanol group, alkoxy group, alkoxycarbonyl group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxyl group, carboxylate group, acyl group, acyloxy group, sulfino group, sulfo group, sulfonate group, phosphino group , A phosphinyl group, a phosphono group, a phosphonato group, a hydroxyimino group, a saturated or unsaturated alkyl ether group, a saturated or unsaturated alkyl thioether group, an aryl ether group, and an aryl thioether group.

Since the basic substance to be generated is NHR ²¹ R ²² , examples thereof include primary amines, secondary amines, and heterocyclic compounds. The amine includes an aliphatic amine and an aromatic amine, respectively. In addition, the heterocyclic compound here means that NHR ²¹ R ²² has a cyclic structure and has aromaticity. Non-aromatic heterocyclic compounds that are not aromatic heterocyclic compounds are included here in aliphatic amines as alicyclic amines.

Furthermore, the NHR ²¹ R ^{22 to be} produced is not only a basic substance such as a monoamine having only one NH group capable of forming an amide bond, but also 2 NH groups capable of forming an amide bond such as diamine, triamine, and tetraamine. It may be a basic substance having two or more. In the case where the generated NHR ²¹ R ²² is a basic substance having two or more NH groups, an NH group capable of forming an amide bond is formed at one or more terminals of R ²¹ and / or R ^{22 in} the above formula (a). The structure which the photolatent part which generate | occur | produces the base which has by irradiation of electromagnetic waves and a heating has couple | bonded further is mentioned. As the photolatent site, to one or more ends of the ^{R 21} and / or ^{R 22} in the formula (a), residues obtained by removing ^{R 21} and / or ^{R 22} of formula (a) is further bound Structure.

  Aliphatic primary amines include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, sec-butylamine, tert-butylamine, pentylamine, isoamylamine, tert-pentylamine, cyclopentylamine, hexylamine, cyclohexylamine , Heptylamine, cycloheptaneamine, octylamine, 2-octaneamine, 2,4,4-trimethylpentan-2-amine, cyclooctylamine and the like.

  Examples of the aromatic primary amine include aniline, 2-aminophenol, 3-aminophenol, and 4-aminophenol.

  Aliphatic secondary amines include dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, ethylmethylamine, aziridine, azetidine, pyrrolidine, piperidine, azepan, azocan, methylaziridine, dimethylaziridine, methylazetidine, dimethyl Examples thereof include azetidine, trimethylazetidine, methylpyrrolidine, dimethylpyrrolidine, trimethylpyrrolidine, tetramethylpyrrolidine, methylpiperidine, dimethylpiperidine, trimethylpiperidine, tetramethylpiperidine, pentamethylpiperidine and the like, among which alicyclic amine is preferable.

  Aromatic secondary amines include methylaniline, diphenylamine, and N-phenyl-1-naphthylamine. In addition, as an aromatic heterocyclic compound having an NH group capable of forming an amide bond, an imino bond (—N═C (—R) —, —C (═NR) — Here, R preferably has a hydrogen atom or a monovalent organic group), and examples thereof include imidazole, purine, triazole, and derivatives thereof.

As amines higher than diamine, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, Linear aliphatic alkylenediamines such as 1,9-nonanediamine and 1,10-decanediamine; 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl- 1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2,3- Branched aliphatic alkylenediamine such as dimethyl-1,4-butanediamine; diethylenetriamine, triethylenetetramine, tetraethylenepentami Polyethylene amines represented by the general formula _{NH 2 (CH 2 CH 2 NH} ) n H and the like; cyclohexane diamine, methylcyclohexane diamine, isophorone diamine, norbornane dimethylamine, tricyclodecane dimethylamine, alicyclic such as menthenediamine Diamine; aromatic diamine such as p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4′-diaminodiphenylmethane, diaminodiphenylsulfone; benzenetriamine, melamine, 2,4, Examples include triamines such as 6-triaminopyrimidine; tetraamines such as 2,4,5,6-tetraaminopyrimidine.

Depending on the substituents introduced at the positions of R ²¹ and R ²² , the thermophysical properties and basicity of the basic substance to be generated are different.
Catalytic action such as lowering the reaction start temperature for the reaction from the polyimide component to the final product, the basic substance having a large basicity has a larger effect as a catalyst, and at a lower temperature with a smaller amount of addition. Reaction to the final product. In general, secondary amines have higher basicity than primary amines, and their catalytic effect is greater.
In addition, aliphatic amines are preferred over aromatic amines because they are more basic.

  Further, when the base generated in the present invention is a secondary amine and / or a heterocyclic compound, it is preferable from the viewpoint of increasing the sensitivity as a base generator. It is presumed that this is because the use of a secondary amine or a heterocyclic compound eliminates active hydrogen at the amide bond site, thereby changing the electron density and improving the sensitivity of isomerization.

Further, from the viewpoint of the thermophysical properties of the base to be eliminated and the basicity, the organic groups of R ²¹ and R ²² each independently preferably have 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably carbon. It is preferable that it is number 1-8.

  The base generated from the base generator represented by the chemical formula (a) preferably has one NH group capable of forming an amide bond. When the generated base has two or more NH groups capable of forming an amide bond, the base generator has two or more amide bonds that are cleaved by irradiation with electromagnetic waves and heating, for example, cinnamic acid derivatives There will be two or more photophores, such as residues, per molecule. In such a case, since the molecular weight is usually increased, there is a problem that the solvent solubility is deteriorated. In addition, when there are two or more photophores in one molecule, it becomes a base if one amide bond where the photophore and the base are bonded is cleaved, but a base that still contains the photophore has a large molecular weight. Therefore, the diffusibility is deteriorated, and the sensitivity when used as a base generator is deteriorated. Furthermore, when synthesizing a base generator, if there is one light-absorbing group, it is synthesized by adding an excessive amount of a relatively inexpensive base, but if there are two or more light-absorbing groups, it is relatively expensive. It is necessary to add an excessive amount of the raw material of the photophore portion. In addition, in the case of a base having two or more NH groups capable of forming an amide bond, there is a problem that purification after synthesis is difficult. In particular, when combined with a polyimide precursor, it is preferable to have one NH group capable of forming an amide bond.

  The structure of the generated secondary amine and / or heterocyclic compound is preferably represented by the following formula (b).

(In formula (b), R ²¹ and R ²² are each independently a monovalent organic group having an alkyl group having 1 to 20 carbon atoms which may have a substituent, or a substituent. Or a cycloalkyl group having 4 to ²² carbon atoms, R ²¹ and R ²² may be the same or different, and R ²¹ and R ²² are bonded to each other to form a cyclic structure. Or may contain a heteroatom bond.)

In R ²¹ and R ²² of formula (b), the alkyl group may be linear or branched. The alkyl group preferably further has 1 to 12 carbon atoms, and the cycloalkyl group preferably further has 4 to 14 carbon atoms. Also, cycloaliphatic amine which is the R ²¹ and R ²² are bonded which may have a substituent cyclic structure having 4 to 12 carbon atoms are also preferred. Moreover, heterocyclic compounds become R ²¹ and R ²² are bonded which may have a substituent ring structure having 2 to 12 carbon atoms are also preferred.

R ²³ , R ²⁴ , R ²⁵ and R ²⁶ are each independently hydrogen, halogen, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group Group, phosphinyl group, phosphono group, phosphonato group, amino group, ammonio group or monovalent organic group, which may be the same or different. R ²³ , R ²⁴ , R ²⁵ and R ²⁶ , or two or more of them may be bonded to form a cyclic structure, or may contain a hetero atom bond.
Examples of the halogen include fluorine, chlorine, bromine and the like.
The monovalent organic group is not particularly limited, and may be a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, an aryl group, an aralkyl group, and a saturated or unsaturated halogenated alkyl group, a cyano group, an isocyano group, Examples include cyanato group, isocyanato group, thiocyanato group, isothiocyanato group, alkoxy group, alkoxycarbonyl group, carbamoyl group, thiocarbamoyl group, carboxyl group, carboxylate group, acyl group, acyloxy group, and hydroxyimino group. These organic groups may contain bonds and substituents other than hydrocarbon groups such as heteroatoms in the organic group, and these may be linear or branched.

The bond other than the hydrocarbon group in the organic group of R ^{23 to} R ²⁶ is not particularly limited as long as the effects of the present invention are not impaired, and an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, and an ester bond. Amide bond, urethane bond, carbonate bond, sulfonyl bond, sulfinyl bond, azo bond and the like.
From the viewpoint of heat resistance, the bond other than the hydrocarbon group in the organic group includes an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, a urethane bond, and an imino bond (—N═C (— R)-, -C (= NR)-: where R is a hydrogen atom or a monovalent organic group), a carbonate bond, a sulfonyl bond, or a sulfinyl bond.

The substituent other than the hydrocarbon group in the organic group of R ^{23 to} R ²⁶ is not particularly limited as long as the effect of the present invention is not impaired. A halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group, Isocyano group, cyanato group, isocyanato group, thiocyanato group, isothiocyanato group, silyl group, silanol group, alkoxy group, alkoxycarbonyl group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxyl group, carboxylate group, acyl group Acyloxy group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, hydroxyimino group, saturated or unsaturated alkyl ether group, saturated or unsaturated alkyl thioether group, aryl ether group, and An aryl thioether group, Amino group _{(-NH 2, -NHR, -NRR '} : wherein, R and R' each independently represent a hydrocarbon group) include an ammonio group. The hydrogen contained in the substituent may be substituted with a hydrocarbon group. Further, the hydrocarbon group contained in the substituent may be any of linear, branched, and cyclic.
Among them, examples of the substituent other than the hydrocarbon group in the organic group represented by R ^{23 to} R ²⁶ include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group, an isocyano group, a cyanato group, an isocyanato group, a thiocyanato group, and an isothiocyanato group. , Silyl group, silanol group, alkoxy group, alkoxycarbonyl group, carbamoyl group, thiocarbamoyl group, nitro group, nitroso group, carboxyl group, carboxylate group, acyl group, acyloxy group, sulfino group, sulfo group, sulfonate group, phosphino A group, a phosphinyl group, a phosphono group, a phosphonato group, a hydroxyimino group, a saturated or unsaturated alkyl ether group, a saturated or unsaturated alkyl thioether group, an aryl ether group, and an aryl thioether group are preferred.

Examples of the monovalent organic group include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, and a propyl group; cycloalkyl groups having 4 to 23 carbon atoms such as a cyclopentyl group and a cyclohexyl group; a cyclopentenyl group and a cyclohexenyl group. A cycloalkenyl group having 4 to 23 carbon atoms such as a group; an aryloxyalkyl group having 7 to 26 carbon atoms (-ROAr group) such as a phenoxymethyl group, a 2-phenoxyethyl group and a 4-phenoxybutyl group; a benzyl group, 3 An aralkyl group having 7 to 20 carbon atoms such as phenylpropyl group; an alkyl group having 2 to 21 carbon atoms having a cyano group such as cyanomethyl group and β-cyanoethyl group; 1 to 20 carbon atoms having a hydroxyl group such as hydroxymethyl group Alkyl group, methoxy group, ethoxy group, etc., C1-C20 alkoxy group, acetamide group, benzenesulfonamide group _{C 6 H 5 SO 2 NH 2} -) amide group having a carbon number of 2 to 21, such as a methylthio group, an alkylthio group (-SR group having 1 to 20 carbon atoms such as an ethylthio group), an acetyl group, carbon atoms such as benzoyl group 6 to 20 carbon atoms such as an acyl group having 1 to 20 carbon atoms, a methoxycarbonyl group, an acetoxy group and the like, an ester group having 2 to 21 carbon atoms (—COOR group and —OCOR group), a phenyl group, a naphthyl group, a biphenyl group, a tolyl group, etc. ˜20 aryl group, electron donating group and / or electron withdrawing group substituted aryl group having 6 to 20 carbon atoms, electron donating group and / or electron withdrawing group substituted benzyl group, cyano group, and A methylthio group (—SCH ₃ ) is preferred. The alkyl moiety may be linear, branched or cyclic.

Two or more of R ^{23 to} R ²⁶ may be bonded to form a cyclic structure.
The cyclic structure is a combination of two or more selected from the group consisting of saturated or unsaturated alicyclic hydrocarbons, heterocycles, and condensed rings, and the alicyclic hydrocarbons, heterocycles, and condensed rings. The structure which becomes may be sufficient. For ^example, R 23 ^{to R 26} is formed by combining two or more of ^them, naphthalene share atoms of the benzene ring of R 23 ^{to R 26} are attached, anthracene, phenanthrene, and fused ring indene In this case, the absorption wavelength is preferable from the viewpoint of increasing the wavelength.

In the present invention, at least one of R ²³ , R ²⁴ , R ²⁵ and R ²⁶ is a hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, A phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, or an ammonio group is desirable. It is possible to adjust the wavelength of light to be absorbed by introducing at least one substituent as described above into the substituents R ^{23 to} R ²⁶ , and absorbing a desired wavelength by introducing the substituent. It can also be made to do. It is also possible to improve the solubility and compatibility with the polymer precursor to be combined. Thereby, it is possible to improve the sensitivity while considering the absorption wavelength of the polyimide component to be combined.

  As a guideline of what substituents should be introduced to shift the absorption wavelength with respect to a desired wavelength, the Interspection of the Ultraviolet Products (AI Scott 1964) and the spectrum of organic compounds The table described in the identification method 5th edition (RM Silverstein 1993) can be referred to.

Among them, compared the base generator in the present ^invention, R ^23, R ^24, if at least one of ^{R 25} and ^{R 26} is a hydroxyl ^group, a compound containing no hydroxyl group in R ^23, R ^{24, R 25} and ^{R 26,} This is preferable from the viewpoint of improving the solubility in a basic aqueous solution and the like and increasing the absorption wavelength. In particular, when R ²⁶ is a phenolic hydroxyl group, a reaction site for cyclization of a compound isomerized to a cis isomer increases, which is preferable from the viewpoint of easy cyclization.

  The structure represented by the chemical formula (a) has a geometric isomer at the (—CH═CH—C (═O) —) moiety, but it is preferable to use only the trans isomer. However, cis isomers that are geometric isomers may be mixed during synthesis and purification steps and storage, and in this case, a mixture of trans isomer and cis isomer may be used. It is preferable that the ratio of cis-isomer is less than 10%.

In addition, the weight decreasing temperature of the base generator represented by the chemical formula (a) can be adjusted by appropriately selecting the substituents R ^{23 to} R ²⁶ .

The heating temperature for generating a base when using the base generator represented by the above formula (a) is appropriately selected depending on the polyimide component to be combined and the purpose, and is not particularly limited. Heating by the temperature (for example, room temperature) of the environment where the base generator is placed may be used, and in this case, the base is gradually generated. Further, since the base is also generated by heat generated as a by-product during irradiation with electromagnetic waves, heating may be performed substantially simultaneously with the heat generated as a by-product during irradiation with electromagnetic waves. From the viewpoint of increasing the reaction rate and generating the base efficiently, the heating temperature for generating the base is preferably 30 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 100 ° C. or higher, Especially preferably, it is 120 degreeC or more. However, depending on the polyimide components used in combination, for example, the unexposed portion is cured by heating at 60 ° C. or higher, and therefore, a suitable heating temperature is not limited to the above.
Moreover, in order to prevent decomposition | disassembly other than base generation | occurrence | production of the base generator represented by the said Formula (a), it is preferable to heat at 300 degrees C or less.

  The base generator represented by the above formula (a) generates a base only by irradiation with electromagnetic waves, but generation of the base is promoted by heating appropriately. Therefore, in order to generate a base efficiently, when using the base generator represented by the above formula (a), the base is generated by heating after exposure or simultaneously with exposure. Exposure and heating may be performed alternately. The most efficient method is a method of heating simultaneously with exposure.

  The method for synthesizing the base generator represented by the chemical formula (a) in the present invention will be described by taking 2-hydroxycinnamic acid amide as an example, but the present invention is not limited thereto. The base generator in the present invention can be synthesized by a plurality of conventionally known synthesis routes.

2-hydroxycinnamic amide can be synthesized, for example, by reacting 2-hydroxy cinnamic acid with cyclohexylamine. The desired product can be obtained by dissolving 2-hydroxycinnamic acid and cyclohexylamine in tetrahydrofuran in the presence of a condensing agent such as 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride and stirring.
Cinnamic acid into which each substituent is introduced can be synthesized by performing wittig reaction, Knoevenagel reaction, or Perkin reaction on hydroxybenzaldehyde having a corresponding substituent. Among these, the wittig reaction is preferable from the viewpoint that a trans isomer can be selectively obtained. For example, the aldehyde having the corresponding substituent can be synthesized by performing Duff reaction or Vilsmeier-Haack reaction on phenol having the corresponding substituent.

  The base generator represented by the chemical formula (a) in the present invention has absorption with respect to at least a part of the exposure wavelength in order to sufficiently exhibit the function of base generation for the polyimide component to be the final product. There is a need. The wavelength of a high-pressure mercury lamp that is a general exposure light source includes 365 nm, 405 nm, and 436 nm. For this reason, it is preferable that the base generator represented by the chemical formula (a) in the present invention absorbs at least one electromagnetic wave having a wavelength of 365 nm, 405 nm, or 436 nm. In such a case, it is preferable because the number of applicable polyimide components is further increased.

  The base generator represented by the chemical formula (a) has a molar extinction coefficient of 100 or more at an electromagnetic wave wavelength of 365 nm, or 1 or more at 405 nm, because the number of applicable polyimide components further increases. preferable.

It should be noted that the fact that the base generator represented by the chemical formula (a) in the present invention has absorption in the wavelength region is expressed by the chemical formula (a) in a solvent (for example, acetonitrile) that does not absorb in the wavelength region. bases generating agent 1 × ¹⁰ -4 mol / L or less of the concentration ^{(usually, 1 × 10 -4 mol / L~1} × 10 -5 mol / L or so. so as to give suitable absorption intensity, as appropriate, It may be clarified by measuring the absorbance with an ultraviolet-visible spectrophotometer (for example, UV-2550, manufactured by Shimadzu Corporation).

  In addition, as the radically crosslinkable monomer used in the present invention, for example, a compound having one or more ethylenically unsaturated bonds can be used, and more specifically, an amide monomer, (meth) Examples thereof include aromatic vinyl compounds such as acrylate monomers, urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers, epoxy (meth) acrylates, hydroxyl group-containing (meth) acrylates, and styrene. In addition, when the polyimide component has a carboxylic acid component such as polyamic acid in the structure, an ethylenically unsaturated bond-containing compound having a tertiary amino group is used to form an ionic bond with the carboxylic acid of the polyimide component. When the photosensitive polyimide resin composition is used, the contrast of the dissolution rate of the exposed area and the unexposed area is increased.

  Examples of the acid crosslinkable monomer used in the present invention include 4,4′-methylenebis [2,6-bis (hydroxymethyl)] phenol (MBHP), 4,4′-methylenebis [2,6-bis ( Methoxymethyl)] phenol (MBMP), 2,3-dihydroxy-5-hydroxymethylnorbornane, 2-hydroxy-5,6-bis (hydroxymethyl) norbornane, cyclohexanedimethanol, 3,4,8 (or 9)- Fat having a hydroxyl group or a hydroxyalkyl group or both such as trihydroxytricyclodecane, 2-methyl-2-adamantanol, 1,4-dioxane-2,3-diol, 1,3,5-trihydroxycyclohexane Group cyclic hydrocarbons or oxygen-containing derivatives thereof.

  In addition, as the acid-crosslinkable monomer, an amino group-containing compound such as melamine, acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, glycoluril is reacted with formaldehyde or formaldehyde and a lower alcohol, and the hydrogen of the amino group is reacted. A compound in which an atom is substituted with a hydroxymethyl group or a lower alkoxymethyl group can also be used. Of these, those using melamine are melamine-based crosslinking agents, those using urea are urea-based crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea-based crosslinking agents, and glycoluril is used. This was called a glycoluril-based crosslinking agent.

  Examples of the melamine-based crosslinking agent include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxybutyl melamine and the like.

  Examples of the urea-based crosslinking agent include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea and the like.

  Examples of the alkylene urea crosslinking agent include mono and / or dihydroxymethylated ethylene urea, mono and / or dimethoxymethylated ethylene urea, mono and / or diethoxymethylated ethylene urea, mono and / or dipropoxymethylated ethylene Ethylene urea crosslinking agents such as urea, mono and / or dibutoxymethylated ethylene urea; mono and / or dihydroxymethylated propylene urea, mono and / or dimethoxymethylated propylene urea, mono and / or diethoxymethylated propylene urea Propylene urea-based crosslinking agents such as mono- and / or dipropoxymethylated propylene urea, mono- and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy-2-imidazolidinone 1,3-di (methoxymethyl 4,5-dimethoxy-2-imidazolidinone.

  Examples of the glycoluril-based crosslinking agent include mono, di, tri and / or tetrahydroxymethylated glycoluril, mono, di, tri and / or tetramethoxymethylated glycoluril, mono, di, tri and / or tetraethoxy. Examples include methylated glycoluril, mono, di, tri and / or tetrabutoxymethylated glycoluril.

  For photoradical generators used in the present invention, photoinitiators such as photoacid generators, naphthoquinonediazide compounds, crosslinkable components such as ethylenic double bond sites, etc., general photosensitive polyimide resins What is used for a composition can be used.

  In the present invention, when the absorption wavelength of the photobase generator overlaps with the absorption wavelength of the polyimide component and sufficient sensitivity cannot be obtained, the addition of a sensitizer is effective as a means for improving sensitivity. There is a case. Further, even when the photobase generator has an absorption wavelength in the wavelength band of electromagnetic waves that pass through the polyimide component, a sensitizer can be added as a means for improving sensitivity. However, it is necessary to take into consideration the film physical properties of the resulting pattern, particularly the decrease in film strength and heat resistance, accompanying the decrease in the content of the polyimide component due to the addition of the sensitizer.

  Specific examples of compounds called sensitizers include thioxanthone and derivatives thereof such as diethylthioxanthone, cyanine and derivatives thereof, merocyanine and derivatives thereof, coumarins and derivatives thereof, ketocoumarins and derivatives thereof, and ketobiscoumarins. And derivatives thereof, cyclopentanone and derivatives thereof, cyclohexanone and derivatives thereof, thiopyrylium salts and derivatives thereof, quinoline derivatives and derivatives thereof, styrylquinoline derivatives and derivatives thereof, thioxanthene derivatives, xanthene derivatives and Derivatives, oxonol-based and derivatives thereof, rhodamine-based and derivatives thereof, pyrylium salts and derivatives thereof.

Specific examples of cyanine, merocyanine and derivatives thereof include 3,3′-dicarboxyethyl-2,2′thiocyanine bromide, 1-carboxymethyl-1′-carboxyethyl-2,2′-quinocyanine bromide, 1,3′-diethyl-2,2′-quinothiocyanine iodide, 3-ethyl-5-[(3-ethyl-2 (3H) -benzothiazolidene) ethylidene] -2-thioxo-4- And oxazolidine.
Specific examples of coumarin, ketocoumarin and derivatives thereof include 3- (2′-benzimidazole) -7-diethylaminocoumarin, 3,3′-carbonylbis (7-diethylaminocoumarin), and 3,3′-carbonylbiscoumarin. 3,3′-carbonylbis (5,7-dimethoxycoumarin), 3,3′-carbonylbis (7-acetoxycoumarin) and the like.
Specific examples of thioxanthone and derivatives thereof include diethyl thioxanthone and isopropyl thioxanthone.

In addition, benzophenone, acetophenone, anthrone, p, p'-tetramethyldiaminobenzophenone (Michler ketone), phenanthrene, 2-nitrofluorene, 5-nitroacenaphthene, benzoquinone, N-acetyl-p-nitroaniline, p-nitro Aniline, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, N-acetyl-4-nitro-1-naphthylamine, picramide, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9- Benzanthrone, p, p'-tetraethyldiaminobenzophenone, 2-chloro-4-nitroaniline, dibenzalacetone, 1,2-naphthoquinone, 2,5-bis- (4'-diethylaminobenzal) -cyclopentane, 2,6-bis- (4′-diethyla Minobenzal) -cyclohexanone, 2,6-bis- (4′-dimethylaminobenzal) -4-methyl-cyclohexanone, 2,6-bis- (4′-diethylaminobenzal) -4-methyl-cyclohexanone, 4, 4'-bis- (dimethylamino) -chalcone, 4,4'-bis- (diethylamino) -chalcone, p-dimethylaminobenzylideneindanone, 1,3-bis- (4'-dimethylaminobenzal) -acetone 1,3-bis- (4′-diethylaminobenzal) -acetone, N-phenyl-diethanolamine, Np-tolyl-diethylamine, and the like.
In the present invention, one or more of these sensitizers can be used.

c. Solvent The solvent used in the present invention is not particularly limited as long as it can uniformly disperse or dissolve the polyimide component and the photosensitive component. For example, diethyl ether, tetrahydrofuran, dioxane, ethylene glycol Ethers such as dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether Glycol monoethers (so-called cellosolves); methyl ethyl ketone Of ketones such as ethyl acetate, butyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, and glycol monoethers. Esters such as acetates (eg methyl cellosolve acetate, ethyl cellosolve acetate), methoxypropyl acetate, ethoxypropyl acetate, dimethyl oxalate, methyl lactate, ethyl lactate; ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol Alcohols such as glycerin; methylene chloride, 1,1-dichloroethane, 1,2-dichloroethylene, 1-chloropropane, 1-chlorobutane, 1-chloropentane, Halogenated hydrocarbons such as lobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene; N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, etc. Amides; pyrrolidones such as N-methylpyrrolidone; lactones such as γ-butyrolactone; sulfoxides such as dimethyl sulfoxide; other organic polar solvents; and further aromatics such as benzene, toluene and xylene. Group hydrocarbons and other organic nonpolar solvents are also included. These solvents are used alone or in combination.
Among them, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexa Polar solvents such as methylphosphoamide, N-acetyl-2-pyrrolidone, pyridine, dimethyl sulfone, tetramethylene sulfone, dimethyltetramethylene sulfone, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone It is mentioned as a suitable thing.

  Moreover, when using the polyamic acid which is a polyimide precursor as a polyimide component, you may use the solution obtained by the synthesis reaction of polyamic acid as a solvent as it is, and may mix other components there as needed.

d. Others Although the photosensitive polyimide resin composition in this invention contains the said polyimide component, a photosensitive component, and a solvent at least, it may contain another component as needed.
As such other components, a thermosetting component, a non-polymerizable binder resin other than the polyimide precursor, and other additives may be blended to prepare a photosensitive polyimide resin composition.

  In the present invention, various other organic or inorganic low-molecular or high-molecular compounds may be blended in addition to impart processing characteristics and various functionalities to the photosensitive polyimide resin composition. For example, dyes, surfactants, leveling agents, plasticizers, fine particles and the like can be used. The fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, inorganic fine particles such as colloidal silica, carbon, and layered silicate, and these may have a porous or hollow structure. The function or form includes pigments, fillers, fibers, and the like.

  In addition, the blending ratio of other optional components in the present invention is preferably in the range of 0.1 wt% to 20 wt% with respect to the entire solid content of the photosensitive polyimide resin composition. If it is less than 0.1% by weight, the effect of adding the additive is difficult to be exhibited, and if it exceeds 20% by weight, the properties of the finally obtained resin cured product are hardly reflected in the final product.

(Ii) Photosensitive polyimide insulating layer The photosensitive polyimide insulating layer used for this invention is formed using the said photosensitive polyimide resin composition.

The photosensitive polyimide insulating layer in the present invention may be at least one of the above semiconductor layer contact insulating layers. As shown in FIGS. 1 to 3 already described, the gate insulating layer in the top gate type TFT or the bottom gate type It is used as a gate insulating layer and a passivation layer in TFT.
In the present invention, among the above semiconductor layer contact insulating layers, at least one of the gate insulating layer in the top gate type TFT or at least one of the gate insulating layer and the passivation layer in the bottom gate type TFT is preferably used. In particular, among the semiconductor layer contact insulating layers, it is preferably used at least as a gate insulating layer in a top gate type TFT or a passivation layer in a bottom gate type TFT. It is preferably used at least as a gate insulating layer in a top gate type TFT, or as both a gate insulating layer and a passivation layer in a bottom gate type TFT, and more preferably used as all of the semiconductor layer contact insulating layer. It is preferable to be. The gate insulating layer and the passivation layer have a wide contact area with the oxide semiconductor layer among the semiconductor layer contact insulating layers, and are easily affected by outgas from the semiconductor layer contact insulating layer. For this reason, by making these semiconductor layer contact insulating layers into photosensitive polyimide insulating layers, the oxide semiconductor layer can be made to have fewer impurities, and the effects of the present invention can be exhibited more effectively. Because you can. Moreover, it is because it can be set as a simple process.
In addition, the gate insulating layer in the top gate type TFT and the passivation layer in the bottom gate type TFT are usually formed so as to cover the oxide semiconductor layer. Therefore, when the photosensitive polyimide resin composition contains a polyimide precursor, the photosensitive polyimide insulating layer is coated with the photosensitive polyimide resin composition after the formation of the oxide semiconductor layer, and then imidized. Is formed. Accordingly, the water vapor annealing treatment of the oxide semiconductor layer can be performed simultaneously with imidization without separately performing the water vapor annealing treatment of the oxide semiconductor layer, and the switching characteristics can be easily improved. Because.
Furthermore, it is because the effect of this invention can be exhibited more effectively by making all the said semiconductor layer contact insulation layers into the said photosensitive polyimide insulation layers.

The photosensitive polyimide insulating layer in the present invention has insulating properties. Specifically, the volume resistance of the photosensitive polyimide insulating layer is preferably 1.0 × 10 ⁹ Ω · m or more, and more preferably 1.0 × 10 ¹⁰ Ω · m or more. In particular, it is preferably 1.0 × 10 ¹¹ Ω · m or more.
The volume resistance can be measured by a method based on standards such as JIS K6911, JIS C2318, and ASTM D257.

  The film thickness of the photosensitive polyimide insulating layer in the present invention is appropriately set according to the semiconductor layer contact insulating layer used, and can be the same as that of a general semiconductor layer contact insulating layer.

  The photosensitive polyimide insulating layer in the present invention contains at least the above polyimide resin, but in a range where the outgas generation amount can be within a desired range, a leveling agent, a plasticizer, a surfactant, an antifoaming agent, a sensitizer, etc. Or additives such as acrylic resins, phenolic resins, fluorine resins, epoxy resins, cardo resins, vinyl resins, imide resins, novolac resins, etc. good.

  The imidization ratio of the polyimide resin contained in the photosensitive polyimide insulating layer of the present invention is not particularly limited as long as it can exhibit characteristics such as desired insulating properties, heat resistance, low outgassing properties, Specifically, it is preferably 90% or more, and more preferably 95% or more, and particularly preferably 100%, that is, a polyamic acid that does not contain a polyimide precursor. This is because when the imidization ratio is within the above range, the heat resistance and the low outgassing property can be particularly improved.

The method for forming the photosensitive polyimide insulating layer in the present invention is not particularly limited as long as it can be formed using the photosensitive polyimide resin composition, and a photolithography method, a printing method, or the like is used. be able to.
Examples of the photolithography method include a method in which a photosensitive polyimide resin film is formed by coating the photosensitive polyimide resin composition on the substrate, followed by pattern exposure through a mask and development. it can.
As the coating method, a spin coating method, a die coating method, a dip coating method, a bar coating method, a gravure printing method, or a screen printing method can be used.
Moreover, as a printing method, the method using well-known printing techniques, such as gravure printing, flexographic printing, screen printing, and an inkjet method, can be illustrated.

Moreover, when the said photosensitive polyimide resin composition contains a polyimide precursor as said polyimide component, imidation of the said polyimide precursor is performed.
The method for imidizing the polyimide precursor is not particularly limited as long as it is a method capable of imidizing the polyamic acid contained in the polyimide precursor by a dehydration ring-closing reaction. Usually, annealing treatment (heat treatment) A method using can be used.
Such an annealing temperature (heating temperature) is appropriately set in consideration of the type of polyimide precursor to be used, the heat resistance of the members constituting the TFT substrate of the present invention, etc. It is preferably carried out within a range of ˜500 ° C., and particularly preferably within a range of 250 ° C. to 400 ° C., and in particular, from the viewpoint of physical properties after curing of the polyimide precursor and low outgassing properties, 280 ° C. to 400 ° C. It is preferably within the range of ° C. This is because imidization can be sufficiently progressed by being in the above-described temperature range, and thermal deterioration of other members can be suppressed.

In the present invention, the timing for performing the imidization is not particularly limited as long as the photosensitive polyimide insulating layer can be stably formed, but is after the oxide semiconductor layer is formed. That is, when the photosensitive polyimide insulating layer is formed using a photosensitive polyimide resin composition containing the polyimide precursor, the polyimide precursor is imidized after the oxide semiconductor layer is formed. It is preferable that they are formed. This is because the steam annealing treatment of the oxide semiconductor can be performed simultaneously.
Therefore, when the oxide semiconductor layer is formed on the photosensitive polyimide insulating layer, the coating film of the photosensitive polyimide insulating layer is patterned, so that the process can withstand the process before or after imidization. After the imidization (partial imidization) of a part of the polyimide precursor, the oxide semiconductor layer is formed, and then the remaining polyimide precursor is imidized. It is preferable to perform water vapor annealing of the oxide semiconductor layer.

(B) Semiconductor layer contact insulation layer At least one of the semiconductor layer contact insulation layers used in the present invention may be the photosensitive polyimide insulation layer.
In the present invention, the other semiconductor layer contact insulating layer may be an insulating layer other than the photosensitive polyimide insulating layer.
Such other insulating layer is not particularly limited as long as it can exhibit a desired insulating performance, and the same insulating layer as that in a general TFT can be used. Insulating inorganic materials such as silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, barium strontium titanate (BST), lead zirconate titanate (PZT), and those using the above insulating organic materials Can do.

(2) Oxide Semiconductor Layer The oxide semiconductor layer used in the present invention is made of an oxide semiconductor.
Examples of such an oxide semiconductor include zinc oxide (ZnO), titanium oxide (TiO), magnesium zinc oxide (Mg _x Zn _1-x O), cadmium zinc oxide (Cd _x Zn _1-x O), and oxidation. Cadmium (CdO), indium oxide (In ₂ O ₃ ), gallium oxide (Ga ₂ O ₃ ), tin oxide (SnO ₂ ), magnesium oxide (MgO), tungsten oxide (WO), InGaZnO system, InGaSnO system, InGaZnMgO system InAlZnO, InFeZnO, InGaO, ZnGaO, and InZnO can be used.

  The formation method and thickness of the oxide semiconductor layer used in the present invention can be the same as a general method.

(3) TFT
The structure of the TFT used in the present invention is not particularly limited as long as it has the oxide semiconductor layer and the semiconductor contact insulating layer, and includes a top gate structure (positive stagger type, coplanar type structure), bottom A gate structure (inverted stagger type or coplanar type structure) can be given. In the case of the top gate structure (forward stagger type) and the bottom gate structure (reverse stagger type), a top contact structure and a bottom contact structure can be further exemplified. These structures are appropriately selected depending on the type of the oxide semiconductor layer constituting the TFT.

The TFT used in the present invention usually has a gate electrode, a source electrode, and a drain electrode in addition to the oxide semiconductor layer and the semiconductor layer contact insulating layer.
Moreover, you may have a semiconductor layer non-contact insulating layer other than the said semiconductor layer contact insulating layer as needed.

The gate electrode, source electrode, and drain electrode in the present invention are not particularly limited as long as they have desired conductivity, and conductive materials generally used for TFTs can be used. Examples of such materials include Ta, Ti, Al, Zr, Cr, Nb, Hf, Mo, Au, Ag, Pt, Mo-Ta alloys, W-Mo alloys, ITO, IZO and other inorganic materials, and And organic materials having conductivity such as PEDOT / PSS.
The formation method and thickness of the gate electrode, the source electrode, and the drain electrode can be the same as those in general.

The semiconductor layer non-contact insulating layer in the present invention is not particularly limited as long as it has a desired insulating property, and includes the material described in the above section “(1) Semiconductor layer contact insulating layer”. be able to.
In the present invention, it is preferable that the photosensitive polyimide resin composition is used. This is because a simple process can be achieved, cost reduction can be achieved, and switching characteristics can be improved.

2. Substrate The substrate used in the present invention is not particularly limited as long as it can support the TFT. For example, a non-flexible substrate or a flexible flexible substrate is used. Can do.
In the present invention, among these, the flexible substrate is preferable. This is because a flexible TFT substrate that can be easily manufactured in a large area and has excellent impact resistance can be obtained. In addition, the photosensitive polyimide insulating layer is different from an insulating layer made of an inorganic material because it does not cause defects such as cracks even when the substrate is a flexible substrate.

  Examples of the material for the non-flexible substrate in the present invention include glass, silicon, and a metal plate.

Moreover, as the flexible substrate, a film made of a resin or a film in which a film is laminated on a metal foil can be used.
In the present invention, among them, a flexible substrate having the metal foil and a planarizing layer formed on the metal foil and containing polyimide is preferable. In particular, an inorganic compound is included on the planarizing layer. It is preferable to have an adhesion layer.
By having the planarization layer, since the planarization layer containing polyimide is formed on the metal foil, unevenness on the surface of the metal foil can be planarized, and deterioration of the electrical performance of the TFT can be prevented. Because it can.
Further, by having the adhesion layer, the adhesion to the TFT is excellent. Even when the dimensions of the planarizing layer containing polyimide are changed by applying moisture or heat during the production of the flexible TFT substrate, the TFT This is because peeling and cracking can be prevented from occurring in the electrode and the oxide semiconductor layer constituting the layer.
Hereinafter, such a metal foil, a planarization layer, and an adhesion layer will be described in detail.

(1) Adhesion layer The adhesion layer in the present invention is formed on the planarization layer and contains an inorganic compound. Adequate adhesion between the planarization layer containing polyimide and the TFT fabricated on the flexible substrate It is a layer provided to gain power.

  The adhesion layer preferably has smoothness. The surface roughness Ra of the adhesion layer only needs to be smaller than the surface roughness Ra of the metal foil, and specifically, is preferably 25 nm or less, more preferably 10 nm or less. This is because if the surface roughness Ra of the adhesion layer is too large, the electrical performance of the TFT may be deteriorated.

  The surface roughness Ra is a value measured using an atomic force microscope (AFM) or a scanning white interferometer. For example, when measuring using AFM, using Nanoscope V multimode (Veeco), in tapping mode, cantilever: MPP11100, scanning range: 50 μm × 50 μm, scanning speed: 0.5 Hz, surface shape Ra can be obtained by taking an image and calculating an average deviation from the center line of the roughness curve calculated from the obtained image. Further, when measuring using a scanning white interferometer, using New View 5000 (manufactured by Zygo), objective lens: 100 times, zoom lens: 2 times, Scan Length: 15 μm, 50 μm × 50 μm Ra can be obtained by imaging the surface shape of the range and calculating the average deviation from the center line of the roughness curve calculated from the obtained image.

The adhesion layer preferably has heat resistance. This is because a high-temperature treatment is usually performed when manufacturing a TFT. As the heat resistance of the adhesive layer, the 5% weight reduction temperature of the adhesive layer is preferably 300 ° C. or higher.
In addition, about the measurement of 5% weight reduction | decrease temperature, using a thermal analyzer (DTG-60 (made by Shimadzu Corp.)), atmosphere: nitrogen atmosphere, temperature range: 30 degreeC-600 degreeC, temperature increase rate: Thermogravimetric / differential heat (TG-DTA) measurement was performed at 10 ° C./min, and the temperature at which the weight of the sample decreased by 5% was defined as a 5% weight reduction temperature (° C.).

  The adhesion layer usually has an insulating property. This is because insulation is required to produce TFTs on a flexible substrate.

  In addition, the adhesion layer is preferably one that prevents impurity ions contained in the planarization layer containing polyimide from diffusing into the oxide semiconductor layer of the TFT. Specifically, as the ion permeability of the adhesion layer, the iron (Fe) ion concentration is preferably 0.1 ppm or less, or the sodium (Na) ion concentration is preferably 50 ppb or less. In addition, as a measuring method of the density | concentration of Fe ion and Na ion, after sampling and extracting the layer formed on the contact | adherence layer, the method of analyzing by an ion chromatography method is used.

  The inorganic compound constituting the adhesion layer is not particularly limited as long as it satisfies the above-described characteristics. For example, silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, oxidation Examples thereof include chromium and titanium oxide. These may be one type or two or more types.

The adhesion layer may be a single layer or a multilayer.
When the adhesion layer is a multilayer film, a plurality of layers made of the above-described inorganic compound may be laminated, or a layer made of the above-mentioned inorganic compound and a layer made of metal may be laminated. The metal used in this case is not particularly limited as long as an adhesion layer that satisfies the above-described characteristics can be obtained, and examples thereof include chromium, titanium, aluminum, and silicon.
When the adhesion layer is a multilayer film, the outermost layer of the adhesion layer is preferably a silicon oxide film. This is because the silicon oxide film sufficiently satisfies the above characteristics. The silicon oxide in this case is preferably SiO _x (X is in the range of 1.5 to 2.0).

  In the present invention, the adhesion layer 3 is formed on the planarizing layer 2 as illustrated in FIG. 4 and is made of chromium, titanium, aluminum, silicon, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride. A first adhesion layer 3a made of at least one selected from the group consisting of aluminum oxynitride, chromium oxide and titanium oxide, and a second adhesion layer 3b made of silicon oxide and formed on the first adhesion layer 3a. It is preferable to have. The first adhesion layer can enhance the adhesion between the planarization layer and the second adhesion layer, and the second adhesion layer can enhance the adhesion between the planarization layer and the TFT formed on the flexible substrate. It is. Moreover, it is because the 2nd contact | adherence layer which consists of silicon oxides fully satisfy | fills the above-mentioned characteristic.

  The thickness of the adhesion layer is not particularly limited as long as it can satisfy the above-described characteristics, but specifically, it is preferably in the range of 1 nm to 500 nm. Especially, when the adhesion layer has the first adhesion layer and the second adhesion layer as described above, the thickness of the second adhesion layer is larger than that of the first adhesion layer, the first adhesion layer is relatively thin, and the second adhesion layer. The layer is preferably relatively thick. In this case, the thickness of the first adhesion layer is preferably in the range of 0.1 nm to 50 nm, more preferably in the range of 0.5 nm to 20 nm, and still more preferably in the range of 1 nm to 10 nm. The thickness of the second adhesion layer is preferably in the range of 10 nm to 500 nm, more preferably in the range of 50 nm to 300 nm, and still more preferably in the range of 80 nm to 120 nm. This is because if the thickness is too thin, sufficient adhesion may not be obtained, and if the thickness is too thick, cracks may occur in the adhesion layer.

  The adhesion layer may be formed on the entire surface of the metal foil, or may be partially formed on the metal foil. In particular, when the planarizing layer is partially formed on the metal foil as will be described later, the adhesion layer 3 is the same as the planarizing layer 2 as illustrated in FIG. It is preferable that it is partially formed on 1. This is because if the adhesion layer containing an inorganic compound is formed directly on the metal foil, a crack or the like may occur in the adhesion layer. That is, it is preferable that the adhesion layer and the planarization layer have the same shape.

  The method for forming the adhesion layer is not particularly limited as long as it is a method capable of forming a layer made of the above-described inorganic compound or a layer made of the above-mentioned metal. For example, DC (direct current) sputtering, RF (High frequency) magnetron sputtering method, plasma CVD (chemical vapor deposition) method, etc. can be mentioned. In particular, when a layer made of the above-described inorganic compound is formed and a layer containing aluminum or silicon is formed, it is preferable to use a reactive sputtering method. This is because a film having excellent adhesion to the planarizing layer can be obtained.

(2) Planarization layer The planarization layer in this invention is formed on metal foil, contains a polyimide, and is a layer provided in order to planarize the unevenness | corrugation of the metal foil surface.

  The surface roughness Ra of the planarizing layer may be smaller than the surface roughness Ra of the metal foil, but specifically, it is preferably 25 nm or less, more preferably 10 nm or less. The method for measuring the surface roughness is the same as the method for measuring the surface roughness of the adhesion layer.

  The planarization layer contains polyimide, and preferably contains polyimide as a main component. In general, polyimide has water absorption. Since many semiconductor materials used in TFTs are sensitive to moisture, the planarization layer has a relatively low water absorption in order to reduce moisture inside the device and achieve high reliability in the presence of moisture. preferable. One of the indexes of water absorption is a hygroscopic expansion coefficient. The smaller the hygroscopic expansion coefficient, the smaller the water absorption. Therefore, it is preferable that the hygroscopic expansion coefficient of the planarizing layer is as small as possible. Specifically, it is preferably in the range of 0 ppm /% RH to 15 ppm /% RH, more preferably 0 ppm /% RH to 12 ppm /% RH. More preferably, it is in the range of 0 ppm /% RH to 10 ppm /% RH. If the hygroscopic expansion coefficient of the flattening layer is in the above range, the water absorption of the flattening layer can be made sufficiently small, the flexible substrate can be easily stored, and the process for producing a flexible TFT substrate becomes simple. . Furthermore, the smaller the hygroscopic expansion coefficient, the better the dimensional stability. When the hygroscopic expansion coefficient of the flattening layer is large, the flexible substrate warps as the humidity increases due to the difference in expansion coefficient from the metal foil whose hygroscopic expansion coefficient is almost zero, and the adhesion between the flattening layer and the metal foil decreases. There is a case to do. Therefore, it is preferable that the hygroscopic expansion coefficient is small even when a wet process is performed in the manufacturing process.

The hygroscopic expansion coefficient is measured as follows. First, a film having only a planarizing layer is produced. The flattening layer film can be produced by a method of producing a flattening layer film on a heat resistant film (Upilex S 50S (manufactured by Ube Industries)) or a glass substrate, and then peeling the flattening layer film or on a metal substrate. There is a method in which after the flattening layer film is prepared, the metal is removed by etching to obtain the flattening layer film. Next, the obtained flattened layer film is cut into a width of 5 mm and a length of 20 mm to obtain an evaluation sample. The hygroscopic expansion coefficient is measured by a humidity variable mechanical analyzer (Thermo Plus TMA8310 (manufactured by Rigaku Corporation)). For example, the temperature is kept constant at 25 ° C., the humidity is first set to a stable state in an environment of 15% RH, the state is maintained for about 30 minutes to 2 hours, and the humidity of the measurement site is set to 20%. RH and hold for 30 minutes to 2 hours until the sample is stable. Thereafter, the humidity is changed to 50% RH, and the difference between the sample length when the humidity becomes stable and the sample length when the humidity becomes stable at 20% RH is expressed as a change in humidity (in this case, 50-20). 30) and the value divided by the sample length is the hygroscopic expansion coefficient (CHE). At the time of measurement, the tensile weight is set to 1 g / 25000 μm ² so that the weight per cross-sectional area of the evaluation sample becomes the same.

Further, the linear thermal expansion coefficient of the planarizing layer is preferably 15 ppm / ° C. or less, more preferably 10 ppm / ° C. or less, more preferably from the viewpoint of dimensional stability. Is 5 ppm / ° C. or less. The closer the linear thermal expansion coefficient between the flattening layer and the metal foil, the less the warping of the flexible substrate, and the smaller the stress at the interface between the flattening layer and the metal foil when the thermal environment of the flexible substrate changes. The adhesion is improved. Moreover, it is preferable that the flexible substrate does not warp in a temperature environment in the range of 0 ° C. to 100 ° C. for handling, but since the linear thermal expansion coefficient of the planarizing layer is large, the planarizing layer and the metal foil If the linear thermal expansion coefficients differ greatly, the flexible substrate will warp due to changes in the thermal environment.
In addition, when the flexible substrate is not warped, the flexible substrate is cut into a strip shape having a width of 10 mm and a length of 50 mm, and one short side of the obtained sample is fixed on a horizontal and smooth table. The floating distance from the surface of the other short side of the sample is 1.0 mm or less.

  Specifically, the linear thermal expansion coefficient of the planarization layer is preferably in the range of 0 ppm / ° C. to 30 ppm / ° C., more preferably in the range of 0 ppm / ° C. to 25 ppm / ° C. from the viewpoint of dimensional stability. More preferably, it is in the range of 0 ppm / ° C. to 18 ppm / ° C., particularly preferably in the range of 0 ppm / ° C. to 12 ppm / ° C., and most preferably in the range of 0 ppm / ° C. to 7 ppm / ° C.

The linear thermal expansion coefficient is measured as follows. First, a film having only a planarizing layer is produced. The method for producing the planarizing layer film is as described above. Next, the obtained flattened layer is cut into a width of 5 mm and a length of 20 mm to obtain an evaluation sample. The linear thermal expansion coefficient is measured by a thermomechanical analyzer (for example, Thermo Plus TMA8310 (manufactured by Rigaku Corporation)). The measurement conditions were a heating rate of 10 ° C./min, a tensile load of 1 g / 25,000 μm ² so that the weight per cross-sectional area of the evaluation sample was the same, and an average linear thermal expansion within a range of 100 ° C. to 200 ° C. The coefficient is the linear thermal expansion coefficient (CTE).

  The planarizing layer has an insulating property. Specifically, it can be the same as the photosensitive polyimide insulating layer.

  The polyimide constituting the planarizing layer is not particularly limited as long as it satisfies the above characteristics. For example, it is possible to control the hygroscopic expansion coefficient and the linear thermal expansion coefficient by appropriately selecting the structure of polyimide.

  The polyimide is preferably a polyimide containing an aromatic skeleton from the viewpoint of making the linear thermal expansion coefficient and hygroscopic expansion coefficient of the planarizing layer suitable for a flexible substrate. Among polyimides, polyimides containing aromatic skeletons are derived from their rigid and highly planar skeletons, which are excellent in heat resistance, insulation in thin films, and have a low coefficient of linear thermal expansion. It is preferably used for the chemical layer.

  Since polyimide is required to have low hygroscopic expansion and low linear thermal expansion, it is preferable to have a repeating unit represented by the following formula (21). Such polyimide exhibits high heat resistance and insulation properties derived from its rigid skeleton, and exhibits linear thermal expansion equivalent to that of metal. Furthermore, the hygroscopic expansion coefficient can be reduced.

(In Formula (21), R ³¹ is a tetravalent organic group, R ³² is a divalent organic group, and R ³¹ and R ³² that are repeated may be the same or different. m is a natural number of 1 or more.)

In formula (21), R ³¹ is generally a structure derived from tetracarboxylic dianhydride, and R ³² is a structure derived from diamine.

  The tetracarboxylic dianhydride applicable to the polyimide contained in the planarization layer in the present invention is not particularly limited as long as it can form a polyimide having the above-described characteristics. Specifically, A tetracarboxylic dianhydride applicable to the polyimide component described in the section “1. TFT” can be used.

The tetracarboxylic dianhydride preferably used from the viewpoints of the heat resistance of the polyimide contained in the planarization layer and the linear thermal expansion coefficient in the present invention is an aromatic tetracarboxylic dianhydride. Particularly preferably used tetracarboxylic dianhydrides include pyromellitic dianhydride, merophanic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4. , 4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 2, 2 ′, 6,6′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1, Examples include 1,3,3,3-hexafluoropropane dianhydride and bis (3,4-dicarboxyphenyl) ether dianhydride.
Among these, from the viewpoint of reducing the hygroscopic expansion coefficient, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2, 3,2 ′, 3′-biphenyltetracarboxylic dianhydride and bis (3,4-dicarboxyphenyl) ether dianhydride are particularly preferred.

When tetracarboxylic dianhydride into which fluorine is introduced is used as the tetracarboxylic dianhydride to be used in combination, the hygroscopic expansion coefficient of polyimide is lowered. However, a polyimide precursor having a skeleton containing fluorine is difficult to dissolve in a basic aqueous solution and needs to be developed with a mixed solution of an organic solvent such as alcohol and a basic aqueous solution.
In addition, pyromellitic dianhydride, merophanic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride When rigid tetracarboxylic dianhydrides such as 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride and 1,4,5,8-naphthalene tetracarboxylic dianhydride are used, This is preferable because the linear thermal expansion coefficient is small. Among these, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 2,3,3 ′, 4′-biphenyltetracarboxylic acid are used from the viewpoint of the balance between the linear thermal expansion coefficient and the hygroscopic expansion coefficient. The dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride is particularly preferred.

  When the tetracarboxylic dianhydride has an alicyclic skeleton, the transparency of the polyimide precursor is improved, so that the sensitivity becomes high. On the other hand, the heat resistance and insulation of polyimide tend to be inferior compared to aromatic polyimide.

When an aromatic tetracarboxylic dianhydride is used, there is a merit that it becomes a polyimide having excellent heat resistance and a low linear thermal expansion coefficient. Therefore, in the polyimide, it is preferable that 33 mol% or more of R ³¹ in the formula (21) has any structure represented by the following formula.

When the polyimide contained in the planarization layer in the present invention includes any structure of the above formula, it is derived from these rigid skeletons and exhibits low linear thermal expansion and low hygroscopic expansion. Furthermore, there is also an advantage that it is easily available on the market and is low cost.
The polyimide having the structure as described above is a polyimide that exhibits high heat resistance and a low linear thermal expansion coefficient. Therefore, the content of the structure represented by the above formula is preferably closer to 100 mol% of R ^{31 in} the above formula (21), but at least 33% of R ^{31 in} the above formula (21) is contained. do it. In particular, the content of the structure represented by the above formula is preferably 50 mol% or more, and more preferably 70 mol% or more, of R ³¹ in the formula (21).

  On the other hand, the diamine component applicable to the polyimide contained in the planarization layer in the present invention can also be used alone or in combination of two or more diamines. The diamine component used is not particularly limited, and for example, a diamine component applicable to the polyimide component described in the section “1. TFT” can be used.

The diamine can be selected depending on the desired physical properties. If a rigid diamine such as p-phenylenediamine is used, the polyimide has a low expansion coefficient. Rigid diamines include p-phenylenediamine, m-phenylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2, 6 as diamines in which two amino groups are bonded to the same aromatic ring. -Diaminonaphthalene, 2,7-diaminonaphthalene, 1,4-diaminoanthracene and the like can be mentioned.
In addition, diamines in which two or more aromatic rings are bonded by a single bond, and two or more amino groups are each bonded directly or as part of a substituent on a separate aromatic ring, for example, Some are represented by the following formula (22). Specific examples include benzidine and the like.

(In formula (22), b is a natural number of 0 or 1 or more, and the amino group is bonded to the meta position or the para position with respect to the bond between the benzene rings.)

Furthermore, in the above formula (22), a diamine having a substituent at a position where the amino group on the benzene ring is not substituted and which does not participate in the bond with another benzene ring can also be used. These substituents are monovalent organic groups, but they may be bonded to each other. Specific examples include 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diamino. Biphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl and the like can be mentioned.
In addition, when fluorine is introduced as a substituent of the aromatic ring, the hygroscopic expansion coefficient can be reduced. However, polyimide precursors containing fluorine, especially polyamic acid, are difficult to dissolve in a basic aqueous solution, and in the case of partially forming a planarizing layer on a metal foil, alcohol or the like is used during the processing of the planarizing layer. It may be necessary to develop with a mixed solution of the organic solvent.

  On the other hand, when a diamine having a siloxane skeleton such as 1,3-bis (3-aminopropyl) tetramethyldisiloxane is used as the diamine, the adhesion with the metal foil is improved, or the elastic modulus of the polyimide is reduced. The glass transition temperature can be lowered.

  Here, the selected diamine is preferably an aromatic diamine from the viewpoint of heat resistance. However, depending on the desired physical properties, the diamine may be an aliphatic diamine or siloxane within a range not exceeding 60 mol%, preferably not exceeding 40 mol%. Non-aromatic diamines such as diamines may be used.

Moreover, in the polyimide contained in the planarization layer in this invention, it is preferable that 33 mol% or more among R ^<32 > in said Formula (21) is either structure represented by a following formula.

(R ⁴¹ is a divalent organic group, oxygen atom, sulfur atom, or sulfone group, and R ⁴² and R ⁴³ are a monovalent organic group or a halogen atom.)

When the polyimide contained in the planarization layer in the present invention includes any structure of the above formula, it is derived from these rigid skeletons and exhibits low linear thermal expansion and low hygroscopic expansion. Furthermore, there is also an advantage that it is easily available on the market and is low cost.
When it has the above structure, the heat resistance of a polyimide improves and a linear thermal expansion coefficient becomes small. Therefore, the content of the structure represented by the above formula is preferably as close as possible to 100 mol% of R ^{32 in} the above formula (21), but at least 33% or more of R ^{32 in} the above formula (21). It may be contained. Among them, the content of the structure represented by the above formula is preferably at least 50 mol% of R ³² in the formula (21), is preferably further 70 mol% or more.

Generally, the linear thermal expansion coefficient of the metal foil, that is, the linear thermal expansion coefficient of the metal is fixed to some extent. Therefore, the linear thermal expansion coefficient of the planarizing layer is determined according to the linear thermal expansion coefficient of the metal foil to be used, and the polyimide structure Is preferably selected as appropriate.
Specifically, the linear thermal expansion coefficient of the metal foil is determined according to the linear thermal expansion coefficient of the TFT, the linear thermal expansion coefficient of the planarizing layer is determined according to the linear thermal expansion coefficient of the metal foil, and the polyimide It is preferable to select the structure appropriately.

  In the present invention, the planarizing layer preferably contains a polyimide having a repeating unit represented by the above formula (21), and this polyimide and another polyimide may be appropriately laminated as necessary. They may be combined and used as a planarization layer.

Moreover, the polyimide which has a repeating unit represented by the said Formula (21) can be obtained using the photosensitive polyimide resin composition which has a polyimide component and a photosensitive component. This is because by using such a photosensitive material, it can be manufactured by a simple process.
Regarding the characteristics such as the 5% weight loss temperature of the photosensitive polyimide resin composition and the components such as the photosensitive component to be used, refer to “(1) Semiconductor layer contact insulating layer” of “1. TFT” above. It can be the same as that described in the section.

  When the polyimide in this invention is formed using the photosensitive polyimide resin composition containing a polyimide precursor as a polyimide component, it is metal foil that the said polyimide precursor is developable with basic aqueous solution. When the planarization layer is partially formed thereon, it is preferable from the viewpoint of ensuring the safety of the working environment and reducing the process cost. This is because the basic aqueous solution can be obtained at a low cost, and the waste liquid treatment cost and the equipment cost for ensuring work safety are low, so that production at a lower cost is possible.

Generally, the linear thermal expansion coefficient of the metal foil, that is, the linear thermal expansion coefficient of the metal is fixed to some extent. Therefore, the linear thermal expansion coefficient of the planarizing layer is determined according to the linear thermal expansion coefficient of the metal foil to be used, and the polyimide structure Is preferably selected as appropriate.
Specifically, the linear thermal expansion coefficient of the metal foil is determined according to the linear thermal expansion coefficient of the TFT, the linear thermal expansion coefficient of the planarizing layer is determined according to the linear thermal expansion coefficient of the metal foil, and the polyimide It is preferable to select the structure appropriately.

  In the present invention, it is preferable that the planarizing layer contains a polyimide having a repeating unit represented by the above formula (21). However, this polyimide and another polyimide are appropriately laminated as necessary. Or may be used in combination as a planarizing layer.

Although the planarization layer should just contain a polyimide, it is preferable to have a polyimide as a main component especially. By using polyimide as a main component, it is possible to obtain a planarization layer having excellent insulation and heat resistance. In addition, by using polyimide as a main component, the planarization layer can be thinned, the thermal conductivity of the planarization layer is improved, and a flexible substrate having excellent thermal conductivity can be obtained.
Note that that the planarizing layer contains polyimide as a main component means that the planarizing layer contains polyimide to the extent that the above-described characteristics are satisfied. Specifically, the content of the polyimide in the planarization layer is 75% by mass or more, preferably 90% by mass or more, and it is particularly preferable that the planarization layer is made of only polyimide. If the content of the polyimide in the planarizing layer is in the above range, it is possible to exhibit characteristics sufficient to achieve the object of the present invention. Properties such as insulation are improved.

  The planarization layer may contain additives such as a leveling agent, a plasticizer, a surfactant, and an antifoaming agent as necessary.

  The planarizing layer may be formed on the entire surface of the metal foil, or may be partially formed on the metal foil. That is, a metal foil exposed region where the planarizing layer and the adhesion layer are not present and the metal foil is exposed may be provided on the surface of the metal foil where the planarization layer and the adhesion layer are formed.

  When the planarizing layer is partially formed on the metal foil, the planarizing layer 2 is formed except at least the outer edge portion of the metal foil 1 as illustrated in FIGS. 5A and 5B. It may be. 5A is a cross-sectional view taken along the line AA in FIG. 5B, and the adhesion layer is omitted in FIG. 5B. If a flattening layer is formed on the entire surface of the metal foil and the edge of the flattening layer is exposed, polyimide generally exhibits hygroscopicity, so that moisture can be introduced into the device from the end face of the flattening layer during manufacturing or driving. May invade. This moisture deteriorates the device performance or changes the dimension of the planarization layer. Therefore, it is preferable that the planarizing layer is not formed on the outer edge portion of the metal foil, and the portion where the planarizing layer containing polyimide is directly exposed to the outside air is minimized.

In the present invention, that the planarizing layer is partially formed on the metal foil means that the planarizing layer is not formed on the entire surface of the metal foil.
The planarization layer may be formed on one surface of the metal foil except for the outer edge portion of the metal foil, or may be further formed in a pattern on the metal foil except for the outer edge portion of the metal foil.

  The thickness of the planarizing layer is not particularly limited as long as it can satisfy the above-mentioned characteristics, but specifically, it is preferably in the range of 1 μm to 1000 μm, more preferably in the range of 1 μm to 200 μm. More preferably, it is in the range of 1 μm to 100 μm. This is because if the thickness of the flattening layer is too thin, insulation cannot be maintained, or it is difficult to flatten the irregularities on the surface of the metal foil. Also, if the thickness of the flattening layer is too thick, flexibility will be reduced, it will become heavy, drying during film formation will be difficult, and the amount of materials used will increase and the cost will increase. is there. Furthermore, when the heat dissipation function is imparted to the flexible substrate, if the thickness of the planarizing layer is thick, the thermal conductivity is lowered because polyimide has a lower thermal conductivity than metal.

  The method for forming the flattening layer is not particularly limited as long as a flattening layer having good smoothness can be obtained. For example, a method of applying a polyimide solution or a polyimide precursor solution on a metal foil, The method of bonding metal foil and a polyimide film through an adhesive agent, and the method of heat-pressing a metal foil and a polyimide film can be used. Especially, the method of apply | coating a polyimide solution or a polyimide precursor solution is preferable. This is because a flattened layer having excellent smoothness can be obtained. In particular, a method of applying a polyimide precursor solution is suitable. This is because polyimide generally has poor solubility in a solvent. In addition, polyimide having high solubility in a solvent is inferior in physical properties such as heat resistance, linear thermal expansion coefficient, and hygroscopic expansion coefficient.

The application method is not particularly limited as long as it is a method capable of obtaining a flattened layer having good smoothness. In the section “(1) Semiconductor layer contact insulating layer” of “1. TFT” above. The described method can be used.
When applying a polyimide solution or a polyimide precursor solution, the fluidity of the film can be increased and the smoothness can be improved by heating to a temperature higher than the glass transition temperature of the polyimide or polyimide precursor after application.

  Moreover, when forming a planarization layer partially on metal foil, the method of processing directly with a printing method, a photolithographic method, a laser etc. can be used as the formation method. As a photolithography method, for example, the method described in the section “(1) Semiconductor layer contact insulating layer” of “1. TFT”; after forming a polyamic acid as a polyimide precursor on a metal foil, A photosensitive resin film is formed on the film, a photosensitive resin film pattern is formed by a photolithography method, and then the polyamic acid film in the pattern opening is removed using the pattern as a mask, and then the photosensitive resin film pattern is formed. A method of removing and imidizing polyamic acid; a method of developing a polyamic acid film simultaneously with the formation of the photosensitive resin film pattern; a method of removing the photosensitive resin film pattern and imidizing polyamic acid; and a metal foil and A photosensitive resin film pattern is formed on the planarization layer in the state of the planarized layer laminate, and the planarization layer is wet-etched along the pattern. A method of removing a photosensitive resin pattern after etching by a ching method or a dry etching method; patterning one metal foil of a laminate in which a metal foil, a planarizing layer, and a metal foil are laminated, and using the pattern as a mask A method of removing the metal pattern after etching the planarization layer; a method of forming a pattern of the planarization layer directly on the metal foil using a photosensitive polyimide resin composition. As the printing method, the method described in the section “(1) Semiconductor layer contact insulating layer” of “1. TFT” can be used.

(3) Metal foil The metal foil in this invention supports said planarization layer and contact | adherence layer.

  The linear thermal expansion coefficient of the metal foil is preferably in the range of 0 ppm / ° C. to 25 ppm / ° C., more preferably in the range of 0 ppm / ° C. to 18 ppm / ° C., more preferably from the viewpoint of dimensional stability. It is in the range of 0 ppm / ° C. to 12 ppm / ° C., particularly preferably in the range of 0 ppm / ° C. to 7 ppm / ° C. The method for measuring the linear thermal expansion coefficient is the same as the method for measuring the linear thermal expansion coefficient of the planarizing layer, except that the metal foil is cut into a width of 5 mm and a length of 20 mm to obtain an evaluation sample.

  Moreover, it is preferable that metal foil has oxidation resistance. This is because high-temperature treatment is performed when the TFT is manufactured. In particular, when the TFT has an oxide semiconductor layer, the metal foil preferably has oxidation resistance because annealing is performed at a high temperature in the presence of oxygen.

  The metal material constituting the metal foil can be a foil and is not particularly limited as long as it satisfies the above-mentioned characteristics. For example, aluminum, copper, copper alloy, phosphor bronze, stainless steel ( SUS), gold, gold alloy, nickel, nickel alloy, silver, silver alloy, tin, tin alloy, titanium, iron, iron alloy, zinc, molybdenum and the like. Among these, considering the linear thermal expansion coefficients of the metal foil and TFT, titanium or invar having a lower linear thermal expansion coefficient than SUS430 is preferable from the viewpoint of the linear thermal expansion coefficient. However, it is desirable to select not only the linear thermal expansion coefficient but also considering the workability of the foil and the cost due to the oxidation resistance, heat resistance, malleability and ductility of the metal foil.

  The thickness of the metal foil is not particularly limited as long as it can satisfy the above-mentioned characteristics. Specifically, the thickness is preferably in the range of 1 μm to 1000 μm, more preferably in the range of 1 μm to 200 μm. More preferably, it is in the range of 1 μm to 100 μm. If the thickness of the metal foil is too thin, the gas barrier properties against oxygen and water vapor may be reduced, and the strength of the flexible substrate may be reduced. On the other hand, when the thickness of the metal foil is too thick, the flexibility is lowered, the weight is excessive, and the cost is increased.

  The metal foil may be a rolled foil or an electrolytic foil, and is appropriately selected according to the type of metal material. Usually, the metal foil is produced by rolling.

  The surface roughness Ra of the metal foil is larger than the surface roughness Ra of the adhesion layer and the planarization layer, and is, for example, about 50 nm to 200 nm. The method for measuring the surface roughness is the same as the method for measuring the surface roughness of the adhesion layer.

(D) Other structure In this invention, the intermediate | middle layer may be formed between metal foil and the planarization layer. For example, an intermediate layer made of an oxide film obtained by oxidizing a metal constituting the metal foil may be formed between the metal foil and the planarizing layer. Thereby, the adhesiveness of metal foil and a planarization layer can be improved. This oxide film is formed by oxidizing the surface of the metal foil.
Moreover, the said oxide film may be formed also in the surface on the opposite side to the surface in which the planarization layer of metal foil is formed.

3. TFT substrate The TFT substrate of the present invention has at least the TFT and the substrate, but may have other members as necessary.

  The manufacturing method of the TFT substrate of the present invention is not particularly limited as long as it can accurately form the TFT and the substrate, and a general method can be used.

As a use of the TFT substrate of the present invention, it can be used as a TFT array substrate of a display device using a TFT system, and among them, it is preferably used for a TFT array substrate that requires excellent switching characteristics.
Examples of such a display device include a liquid crystal display device, an organic EL display device, and electronic paper. In addition to the display device, a circuit such as an RFID and a sensor can be exemplified.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be specifically described using examples and comparative examples.

[Production example]
1. Preparation of polymid varnish (polyimide precursor solution) (Production Example 1)
4.0 g (20 mmol) of 4,4′-diaminodiphenyl ether (ODA) and 8.65 g (80 mmol) of paraphenylenediamine (PPD) were put into a 500 ml separable flask, and 200 g of dehydrated N-methyl-2 was added. -It dissolved in pyrrolidone (NMP), and it stirred, heating and monitoring with a thermocouple so that liquid temperature might be 50 degreeC with an oil bath under nitrogen stream. After confirming that they were completely dissolved, 29.1 g (99 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) was added thereto gradually over 30 minutes. After the addition, the mixture was stirred at 50 ° C. for 5 hours. Then, it cooled to room temperature and obtained the polyimide precursor solution 1.

(Production Example 2)
The polyimide precursor solution 2 was prepared in the same manner as in Production Example 1, except that the amount of NMP was adjusted so that the reaction temperature and the solution concentration were 17% by weight to 19% by weight, with the compounding ratio shown in Table 1 below. ~ 17 were synthesized.
Acid dianhydrides include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) or pyromellitic dianhydride (PMDA), p-phenylenebistrimellitic acid monoester dianhydride (TAHQ), p-biphenylenebistrimellitic acid monoester dianhydride (BPTME) was used. Diamines include 4,4'-diaminodiphenyl ether (ODA), paraphenylenediamine (PPD), 1,4-Bis (4-aminophenoxy) benzene (4APB), 2,2'-Dimethyl-4,4'-diaminobiphenyl. One or two of (TBHG) and 2,2′-Bis (trifluoromethyl) -4,4′-diaminobiphenyl (TFMB) were used.

(Evaluation of linear thermal expansion coefficient and hygroscopic expansion coefficient)
The polyimide precursor solutions 1 to 17 are applied to a heat-resistant film (Upilex S 50S: manufactured by Ube Industries, Ltd.) pasted on glass, dried on a hot plate at 80 ° C. for 10 minutes, and then heat-resistant film. Was peeled off to obtain a film having a thickness of 15 μm to 20 μm. Thereafter, the film was fixed to a metal frame, and was heat-treated at 350 ° C. for 1 hour in a nitrogen atmosphere (temperature increase rate: 10 ° C./min, natural cooling), and the polyimide resins 1 to 17 having a film thickness of 9 μm to 15 μm A film was obtained.

<Linear thermal expansion coefficient>
The film produced by the above method was cut into a width of 5 mm and a length of 20 mm and used as an evaluation sample. The linear thermal expansion coefficient was measured by a thermomechanical analyzer Thermo Plus TMA8310 (manufactured by Rigaku Corporation). The measurement conditions are as follows: the observation length of the evaluation sample is 15 mm, the heating rate is 10 ° C./min, the tensile load is 1 g / 25000 μm ² so that the weight per cross-sectional area of the evaluation sample is the same, and 100 ° C. to 200 ° C. The average linear thermal expansion coefficient in the range was defined as the linear thermal expansion coefficient (CTE).

<Humidity expansion coefficient>
The film produced by the above method was cut into a width of 5 mm and a length of 20 mm and used as an evaluation sample. The humidity expansion coefficient was measured by a humidity variable mechanical analyzer Thermo Plus TMA8310 (manufactured by Rigaku Corporation). The temperature is kept constant at 25 ° C., and the sample is first stabilized in a humidity of 15% RH. After maintaining this state for approximately 30 minutes to 2 hours, the humidity of the measurement site is set to 20% RH. Further, this state was maintained for 30 minutes to 2 hours until the sample became stable. Thereafter, the humidity is changed to 50% RH, and the difference between the sample length when the humidity becomes stable and the sample length when the humidity becomes stable at 20% RH is expressed as a change in humidity (in this case, 50-20). 30), and the value divided by the sample length was defined as the humidity expansion coefficient (CHE). At this time, the tensile load was set to 1 g / 25000 μm ² so that the weight per cross-sectional area of the evaluation sample was the same.

(Substrate warpage evaluation)
On the 18 μm thick SUS304-HTA foil (manufactured by Toyo Seiki Co., Ltd.), the polyimide precursor solutions 1 to 17 are applied, and the linear thermal expansion coefficient is evaluated so that the film thickness after imidization becomes 10 μm ± 1 μm. A polyimide film of polyimide resins 1 to 17 was formed under the same process conditions as the sample preparation. Then, the laminated body of SUS304 foil and a polyimide film was cut | disconnected to width 10mm x length 50mm, and it was set as the sample for board | substrate curvature evaluation.

This sample was fixed to the SUS plate surface with only one of the short sides of the sample with Kapton tape, heated in an oven at 100 ° C. for 1 hour, and then in the oven heated to 100 ° C., the short side on the opposite side of the sample The distance from the SUS plate was measured. At that time, a sample having a distance of 0 mm or more and 0.5 mm or less was evaluated as “◯”, a sample of more than 0.5 mm and 1.0 mm or less was evaluated as Δ, and a sample of 1.0 mm or more was determined as “X”.
Similarly, when this sample is fixed to the surface of the SUS plate with only one of the short sides of the sample with Kapton tape and left in a constant temperature and humidity chamber at 23 ° C. and 85% Rh for 1 hour, The distance from the short side SUS plate was measured. At that time, a sample having a distance of 0 mm or more and 0.5 mm or less was evaluated as “◯”, a sample of more than 0.5 mm and 1.0 mm or less was evaluated as Δ, and a sample of 1.0 mm or more was determined as “X”.
These evaluation results are shown in Table 2.

Since the linear thermal expansion coefficient of SUS304 foil was 17 ppm / ° C., it was confirmed that the warpage of the laminate was large when the difference in linear thermal expansion coefficient between the polyimide film and the metal foil was large.
Table 2 shows that the smaller the hygroscopic expansion coefficient of the polyimide film, the smaller the warp of the laminate in a high humidity environment.

2. Synthesis of photobase generator (synthesis of photobase generator 1)
Under a nitrogen atmosphere, in a 200 mL three-necked flask equipped with a Dean-Stark apparatus, 8.2 g (39 mmol) of 4,5-dimethoxy-2-nitrobenzaldehyde was dissolved in 100 mL of dehydrated 2-propanol, and 2.0 g (10 mmol, 0.25) of aluminum isopropoxide was dissolved. eq.) was added, and the mixture was heated and stirred at 105 ° C. for 7 hours. During the course of evaporation of the solvent, 40 mL of 2-propanol was added four times. After stopping the reaction with 150 mL of 0.2N hydrochloric acid, extraction was performed with chloroform, and the solvent was distilled off under reduced pressure to obtain 7.2 g of 6-nitroveratryl alcohol.
Under a nitrogen atmosphere, 5.3 g (25 mmol) of 6-nitroveratryl alcohol was dissolved in 100 mL of dehydrated dimethylacetamide in a 200 mL three-necked flask, and 7.0 mL (50 mmol, 2.0 eq) of triethylamine was added. In an ice bath, 5.5 g (27 mmol, 1.1 eq) of p-nitrophenyl chloroformate was added, and the mixture was stirred at room temperature for 16 hours. The reaction solution was poured into 2 L of water, and the resulting precipitate was filtered and purified by silica gel column chromatography to obtain 6.4 g of 4,5-dimethoxy-2-nitrobenzyl-p-nitrophenyl carbonate.
Under a nitrogen atmosphere, 3.6 g (9.5 mmol) of 4,5-dimethoxy-2-nitrobenzyl-p-nitrophenyl carbonate was dissolved in 50 mL of dehydrated dimethylacetamide in a 100 mL three-necked flask, and 5 mL of 2,6-dimethylpiperidine ( 37 mmol, 3.9 eq) and 0.36 g (0.3 eq) of 1-hydroxybenzotriazole were added, and the mixture was heated and stirred at 90 ° C. for 18 hours. The reaction solution was poured into 1 L of a 1% aqueous sodium hydrogen carbonate solution, and the resulting precipitate was filtered and washed with water to give a photobase generator 1N-{[(4,5-dimethoxy- 2.7 g of 2-nitrobenzyl) oxy] carbonyl} -2,6-dimethylpiperidine was obtained.

(Synthesis of photobase generator 2)
Under a nitrogen atmosphere, 0.50 g (3.1 mmol) of o-coumaric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 40 mL of dehydrated tetrahydroxyfuran in a 100 mL three-necked flask, and 1-ethyl-3- (3-dimethylamino) was dissolved. Propyl) carbodiimide hydrochloride (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.59 g (3.1 mmol, 1.0 eq) was added. Piperidine (manufactured by Tokyo Chemical Industry Co., Ltd.) (0.3 ml, 3.1 mmol, 1.0 eq) was added in an ice bath, and the mixture was stirred overnight at room temperature. The reaction solution was concentrated, extracted with chloroform, washed with dilute hydrochloric acid, saturated aqueous sodium hydrogen carbonate solution and brine, and filtered to obtain 450 mg of a photobase generator 2 represented by the following formula.

(Synthesis of photobase generator 3)
In a 100 mL flask, 2.00 g of potassium carbonate was added to 15 mL of methanol. In a 50 mL flask, 2.67 g (6.2 mmol) of ethoxycarbonylmethyl (triphenyl) phosphonium bromide and 945 mg (6.2 mmol) of 2-hydroxy-4-methoxybenzaldehyde were dissolved in 10 mL of methanol and slowly added dropwise to a well-stirred potassium carbonate solution. . After stirring for 3 hours, the completion of the reaction was confirmed by TLC, followed by filtration to remove potassium carbonate and concentration under reduced pressure. After concentration, 50 mL of 1N aqueous sodium hydroxide solution was added and stirred for 1 hour. After completion of the reaction, triphenylphosphine oxide was removed by filtration, and then concentrated hydrochloric acid was added dropwise to acidify the reaction solution. The precipitate was collected by filtration and washed with a small amount of chloroform to obtain 1.00 g of 2-hydroxy-4-methoxycinnamic acid. Subsequently, in a 100 mL three-necked flask, 500 mg (3.0 mmol) of 2-hydroxy-4-methoxycinnamic acid was dissolved in 40 mL of dehydrated tetrahydroxyfuran, and 0.586 g (3.0 mmol) of EDC was added. After 30 minutes, 0.3 ml (3.0 mmol) piperidine was added. After completion of the reaction, the reaction solution was concentrated and dissolved in water. After extraction with diethyl ether, the mixture was washed with saturated aqueous sodium hydrogen carbonate solution, 1N hydrochloric acid and saturated brine. Thereafter, purification by silica gel column chromatography (developing solvent: chloroform / methanol 100/1 to 10/1) yielded 64 mg of a photobase generator 3 represented by the following formula.

(Synthesis of photobase generator 4)
In the synthesis of the photobase generator 3, 80 mg of the photobase generator 4 represented by the following formula was obtained in the same manner as the synthesis of the photobase generator 3 except that cyclohexylamine was used instead of piperidine.

(Synthesis of photobase generator 5)
In the synthesis of photobase generator 3, in the same manner as the synthesis of photobase generator 3, except that 1-hydroxy-2-naphthaldehyde was used instead of 2-hydroxy-4-methoxybenzaldehyde, 75 mg of the photobase generator 5 represented was obtained.

(Synthesis of photobase generator 6)
In the synthesis of the photobase generator 3, in the same manner as the synthesis of the photobase generator 3 except that 2-hydroxy-1-naphthaldehyde was used instead of 2-hydroxy-4-methoxybenzaldehyde, 90 mg of the photobase generator 6 represented was obtained.

[Evaluation of base generator]
The synthesized base generators 1 to 6 were measured and evaluated as follows. The results of molar extinction coefficient and base generation ability are shown in Table 3. In Table 3, the photoreaction rate is a percentage of the number of moles of photoreaction with respect to the number of moles of the base generator used. The results for the 5% weight loss temperature are shown in Table 4.

(1) Molar Absorption Coefficient Base generators 1 to 6 were each dissolved in acetonitrile at a concentration of 1 × 10 ⁻⁴ mol / L, filled in a quartz cell (optical path length 10 mm), and the absorbance was measured. The molar extinction coefficient ε is a value (L / (mol · cm)) obtained by dividing the absorbance of the solution by the thickness of the absorbing layer and the molar concentration of the solute.

(2) Photoreaction rate evaluation For each of the base generators 1 to 6, three 1 mg samples were prepared, and each was dissolved in deuterated acetonitrile in a quartz NMR trough. Using a filter and high-pressure mercury lamp that cuts light with a wavelength of 350 nm or less and transmits 20% of i-line, one is irradiated with light at ² J / cm ² and the other with 20 J / cm ² Light irradiation was performed. The remaining one was not irradiated with light. 1H NMR of each sample was measured to determine the rate of photoreaction.
In addition, about the photoreaction rate, both the base generator and the photoreaction product were quantified by NMR, and the photoreaction rate (%) was calculated from the ratio by the following formula.
Photoreaction rate = photoreaction product amount / (undecomposed base generator amount + photoreaction product amount) × 100

From Table 3, it was clarified that the base generators 1 to 6 have a sensitivity to i-line because it was confirmed that they photoreacted by irradiation with 20 J / cm ² . In the base generator 1, generation of base was not confirmed by irradiation at ² J / cm ² . Photobase generator 6 showed the highest sensitivity, and then photobase generator 3 had the highest sensitivity.

3. Thermogravimetric measurement In order to evaluate the heat resistance of the base generators 1 to 6 and nifedipine (manufactured by Tokyo Chemical Industry), thermogravimetric measurement was performed under the condition of a heating rate of 10 ° C / min, based on the weight at 30 ° C. Went. The results are shown in Table 4.

(Preparation Example 1)
Photobase generator 1 was added to the polyimide precursor solution 1 at 15% by weight of the solid content of the solution to obtain a photosensitive polyimide resin composition 1.

(Preparation Example 2)
A photobase generator 3 was added to the polyimide precursor solution 1 at 10% by weight of the solid content of the solution to obtain a photosensitive polyimide resin composition 2.

(Preparation Example 3)
Photobase generator 3 was added to the polyimide precursor solution 11 at 15% by weight of the solid content of the solution to obtain a photosensitive polyimide resin composition 3.

(Preparation Example 4)
Photobase generator 1 was added to the polyimide precursor solution 11 at 15% by weight of the solid content of the solution to obtain a photosensitive polyimide resin composition 4.

(Preparation Example 5)
15 wt% of the solid content of the solution was added to the polyimide precursor solution 11 to obtain a photosensitive polyimide resin composition 5.

(Preparation Example 6)
15 wt% of the solid content of the solution was added to the polyimide precursor solution 11 to obtain a photosensitive polyimide resin composition 6.

(Preparation Example 7)
15 wt% of the solid content of the solution was added to the polyimide precursor solution 11 to obtain a photosensitive polyimide resin composition 7.

(Preparation Example 8)
15 wt% of the solid content of the solution was added to the polyimide precursor solution 11 to obtain a photosensitive polyimide resin composition 8.

(Preparation Example 9)
30% by weight of the solid content of the solution was added to the polyimide precursor solution 11 to make a photosensitive polyimide resin composition 9.

3. Evaluation of photosensitive resin composition: Evaluation of pattern forming ability Each of the photosensitive polyimide resin composition 1 and the photosensitive polyimide resin composition 2 prepared in the preparation examples has a final film thickness of 4 μm on chrome-plated glass. The film was spin-coated as described above and dried for 15 minutes on a hot plate at 80 ° C. to prepare coating films of the photosensitive polyimide resin composition 1 and the photosensitive polyimide resin composition 2. With a high-pressure mercury lamp using a manual exposure machine through a photomask, the coating film of the photosensitive polyimide resin composition 1 is patterned to 2000 mJ / cm ² and the coating film of the photosensitive polyimide resin composition 2 is 100 mJ / cm. ^Two exposures were performed. Thereafter, each coating film was heated at 155 ° C. for 10 minutes.

  About each coating film, it was immersed in the solution which mixed tetramethylammonium hydroxide 2.38weight% aqueous solution and isopropanol by 9: 1. As a result, a pattern was obtained in which the exposed portion remained undissolved in the developer. Furthermore, it was heated at 350 ° C. for 1 hour to perform imidization. Thus, it became clear that a favorable pattern can be formed by using the said photosensitive polyimide resin compositions 1 and 2.

The photosensitive polyimide resin compositions 3 to 8 prepared in the preparation examples were each spin-coated on a chrome-plated glass so as to have a final film thickness of 4 μm, and dried on a hot plate at 100 ° C. for 15 minutes, Coating films of photosensitive polyimide resin compositions 3 to 8 were produced. The photosensitive polyimide resin composition 3 is 80 mJ / cm ² , the photosensitive polyimide resin composition 4 is 1500 mJ / cm ² , and the photosensitive polyimide resin composition is patterned in a pattern with a high-pressure mercury lamp using a manual exposure machine through a photomask. 5 was 500 mJ / cm ² , photosensitive polyimide resin composition 6 was 400 mJ / cm ² , photosensitive polyimide resin composition 7 was 200 mJ / cm ² , and photosensitive polyimide resin composition 8 was 80 mJ / cm ² exposed. Thereafter, each coating film was heated at 170 ° C. for 10 minutes.

  About each coating film, it was immersed in the solution which mixed tetramethylammonium hydroxide 2.38weight% aqueous solution and isopropanol by 8: 2. As a result, a pattern was obtained in which the exposed portion remained undissolved in the developer.

4). Evaluation of linear thermal expansion coefficient and hygroscopic expansion coefficient Further, the photosensitive polyimide resin compositions 1, 2 and 3 were applied to a heat-resistant film (Upilex S 50S: manufactured by Ube Industries, Ltd.) pasted on glass, After drying on a hot plate at 100 ° C. for 10 minutes, exposure to 2000 mJ / cm ^{2 in} terms of illuminance at a wavelength of 365 nm with a high-pressure mercury lamp, heating on the hot plate at 170 ° C. for 10 minutes, and then peeling off from the heat-resistant film A film having a thickness of 10 μm was obtained. Thereafter, the film is fixed to a metal frame, and heat-treated in a nitrogen atmosphere at 350 ° C. for 1 hour (temperature increase rate 10 ° C./min, natural cooling), photosensitive polyimide 1 having a thickness of 6 μm, photosensitive polyimide 2 and photosensitive polyimide 3 films were obtained.

  The linear thermal expansion coefficient, hygroscopic expansion coefficient, and substrate warpage were evaluated in the same manner as described above. The results are shown in Table 5.

As shown in Table 5, since the linear thermal expansion coefficient of SUS304 foil is 17 ppm / ° C., it was confirmed that the warpage of the laminate was large when the difference in linear thermal expansion coefficient between the polyimide film and the metal foil was large. .
Table 5 also shows that the smaller the hygroscopic expansion coefficient of the polyimide film, the smaller the warpage of the laminate in a high humidity environment.

5. Outgas test Each of the photosensitive polyimide resin composition 3 and the photosensitive polyimide resin composition 4 prepared in the preparation examples was spin-coated on glass so as to have a final film thickness of 10 μm. It was made to dry for minutes and the coating film of the photosensitive polyimide resin composition 3 and the photosensitive polyimide resin composition 4 was produced. The photosensitive polyimide resin composition 3 was exposed to 500 mJ / cm ² and the photosensitive polyimide resin composition 4 was exposed to 2000 mJ / cm ² with a high-pressure mercury lamp using a manual exposure machine through a photomask. Thereafter, each coating film was heated at 170 ° C. for 10 minutes. About each coating film, it heated at 350 degreeC for 1 hour, imidated, and the outgas measurement samples 1 and 2 were obtained.

Moreover, the polyimide precursor solution 11 was spin-coated on glass so that the final film thickness might be 10 micrometers, and it was made to dry for 15 minutes on a 100 degreeC hotplate, and the coating film of the polyimide solution 11 was produced. About each coating film, it heated at 350 degreeC for 1 hour, imidated, and the outgas measurement sample 3 was obtained.
The photosensitive polyimide resin composition 9 prepared in Preparation Example 9 was spin-coated on glass so as to have a final film thickness of 10 μm, and dried on a hot plate at 100 ° C. for 15 minutes. Comparative photosensitive polyimide resin composition 1 A coating film was prepared. 1000 mJ / cm < ² > exposure was performed with the high pressure mercury lamp using the manual exposure machine through the photomask. Then, after heating at 185 degreeC for 10 minute (s), it heated at 350 degreeC for 1 hour, imidated, and the outgas measurement sample 4 was obtained.

UR-5100FX (manufactured by Toray) was spin-coated on glass to a final film thickness of 10 μm and dried on a hot plate at 95 ° C. for 8 minutes to prepare a UR-5100FX coating film. 70 mJ / cm ² exposure was performed with a high-pressure mercury lamp using a manual exposure machine through a photomask. Then, after heating at 80 ° C. for 1 minute, imidization was performed by heating at 140 ° C. for 30 minutes and at 350 ° C. for 1 hour to obtain an outgas measurement sample 5.

XP-1530 (manufactured by HD Microsystems) was spin-coated on glass to a final film thickness of 10 μm, dried on a 70 ° C. hot plate for 2 minutes, and then dried on an 85 ° C. hot plate for 2 minutes. A coating film of -1530 was produced. 300 mJ / cm < ² > exposure was performed with the high pressure mercury lamp using the manual exposure machine through the photomask. Then, after heating at 105 ° C. for 1 minute, imidization was performed by heating at 200 ° C. for 30 minutes and at 350 ° C. for 1 hour to obtain an outgas measurement sample 6.

  About the produced outgas measurement samples 1 to 6, after scraping the sample from the glass, raising the temperature to 100 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, heating at 100 ° C. for 60 minutes, and then 15 minutes or more After cooling in a nitrogen atmosphere, a 5% weight loss temperature was measured based on the weight after cooling when measured at a temperature elevation rate of 10 ° C./min. The results are shown in Table 6.

  As shown in Table 6, the samples using the photobase generator (outgas measurement samples 1 and 2) both had a 5% weight loss temperature of 450 ° C. or higher. Regarding the outgas measurement sample 1, it had a very low low outgassing property comparable to that of the polyamic acid alone (outgas measurement sample 3) (because the photobase generator has a low 50% weight loss temperature, it is derived from the photosensitive component) Less residue). All the other measurement samples had a 5% weight loss temperature of less than 450 ° C.

[Example 1]
A SUS304-HTA base material (manufactured by Koyama Steel Co., Ltd.) having a thickness of 100 μm was coated with a spin coater using the polyimide precursor solution 1 so that the film thickness after imidation was 7 μm ± 1 μm, and 100 ° C. After being dried in the oven for 60 minutes in the air, heat treatment was performed at 350 ° C. for 1 hour in a nitrogen atmosphere (temperature increase rate: 10 ° C./minute, natural cooling) to form an insulating layer.
Next, an aluminum film as a first adhesion layer was formed on the insulating layer with a thickness of 5 nm by a DC sputtering method (film formation pressure 0.2 Pa (argon), input power 1 kW, film formation time 10 seconds). Next, a silicon oxide film as a second adhesion layer was formed with a thickness of 100 nm by RF magnetron sputtering (deposition pressure 0.3 Pa (argon: oxygen = 3: 1), input power 2 kW, deposition time 30 minutes). . Thereby, a substrate for TFT was obtained.

A TFT having a bottom gate / bottom contact structure was fabricated on the TFT substrate. First, an aluminum film having a thickness of 100 nm was formed as a gate electrode film, a resist pattern was formed by photolithography, and then wet etching was performed with a phosphoric acid solution, and the aluminum film was patterned into a predetermined pattern to form a gate electrode. Next, silicon oxide having a thickness of 300 nm was formed as a gate insulating film on the entire surface so as to cover the gate electrode. This gate insulating film uses an RF magnetron sputtering apparatus and is applied to a 6-inch SiO ₂ target with a power of 1.0 kW (= 3 W / cm ² ), a pressure of 1.0 Pa, and a gas of argon + O ₂ (50%). It formed on film-forming conditions. Thereafter, a resist pattern was formed by photolithography and then dry etching was performed to form a contact hole. Next, a 100 nm thick titanium film, aluminum film, and IZO film are deposited on the entire surface of the gate insulating film to form a source electrode and a drain electrode, and then a resist pattern is formed by a photolithography method, and then a hydrogen peroxide solution is formed. Then, wet etching was continuously performed with a phosphoric acid solution, and the titanium film was patterned into a predetermined pattern to form a source electrode and a drain electrode. At this time, the source electrode and the drain electrode were formed on the gate insulating film so as to have a pattern apart from a portion other than directly above the central portion of the gate electrode.

Next, an InGaZnO amorphous oxide thin film (InGaZnO ₄ ) with an In: Ga: Zn ratio of 1: 1: 1 was formed on the entire surface so as to cover the source electrode and the drain electrode so as to have a thickness of 25 nm. The amorphous oxide thin film is 4 inches of InGaZnO (In: Ga: Zn = 1: 1: 1) using an RF magnetron sputtering apparatus under conditions of room temperature (25 ° C.) and Ar: O ₂ of 30:50. It was formed using a target. Then, after forming a resist pattern on the amorphous oxide thin film by photolithography, wet etching was performed with an oxalic acid solution, and the amorphous oxide thin film was patterned to form an amorphous oxide thin film having a predetermined pattern. The amorphous oxide thin film thus obtained was formed on the gate insulating film so as to contact the source electrode and the drain electrode on both sides and straddle the source electrode and the drain electrode.

Subsequently, the photosensitive polyimide resin composition 3 was spin-coated so as to have a final film thickness of 0.1 μm so as to cover the whole, and dried at 100 ° C. for 15 minutes. 80 mJ / cm ² exposure was performed in a pattern with a high-pressure mercury lamp using a manual exposure machine through a photomask. Then, after heating at 170 ° C. for 10 minutes, it was developed with a solution prepared by mixing a 2.38 wt% tetramethylammonium hydroxide aqueous solution and isopropanol at 8: 2, and further heated at 350 ° C. for 1 hour in a nitrogen atmosphere. Imidization was performed.
Next, a TFT was fabricated by annealing in the atmosphere at 300 ° C. for 1 hour.

  When the obtained TFT was driven, it worked well.

[Comparative Example 1]
In the above TFT manufacturing method, an amorphous oxide thin film was formed in the same manner as in Example 1. Subsequently, 100 nm thick silicon oxide was formed as a protective film by RF magnetron sputtering so as to cover the whole, and then a resist pattern was formed by photolithography, followed by dry etching. Annealing was performed in the atmosphere at 300 ° C. for 1 hour to produce a TFT substrate.

[Evaluation results]
The TFT produced in the example showed a decrease in the S value in the TFT transfer characteristics as compared with the comparative example. This is presumably because the trap density at the interface between the oxide semiconductor and the gate insulating film was reduced by the water vapor annealing.

DESCRIPTION OF SYMBOLS 1 ... Metal foil 2 ... Flattening layer 3 ... Adhesion layer 10 ... Substrate 11 ... Oxide semiconductor layer 12S ... Source electrode 12D ... Drain electrode 13G ... Gate electrode 14 ... Gate insulating layer 15 ... Passivation layer 20 ... TFT substrate

Claims (13)

A substrate,
A thin film transistor including an oxide semiconductor layer formed on the substrate and formed of an oxide semiconductor and a semiconductor layer contact insulating layer formed so as to be in contact with the oxide semiconductor layer;
Have
A thin film transistor substrate, wherein at least one of the semiconductor layer contact insulating layers included in the thin film transistor is a photosensitive polyimide insulating layer formed using a photosensitive polyimide resin composition. The photosensitive polyimide resin composition contains a polyimide component and a photosensitive component,
The thin film transistor substrate according to claim 1, wherein the polyimide component includes a polyimide precursor.   The thin film transistor substrate according to claim 1, wherein a 5% weight reduction temperature of the photosensitive polyimide resin composition is 450 ° C. or more. The photosensitive polyimide resin composition contains a polyimide component and a photosensitive component,
4. The thin film transistor substrate according to claim 3, wherein a content of the photosensitive component is in a range of 0.1 parts by weight or more and less than 30 parts by weight with respect to 100 parts by weight of the polyimide component.   5. The thin film transistor substrate according to claim 4, wherein the photosensitive component is mainly composed of a photoacid generator or a photobase generator.   The thin film transistor substrate according to claim 5, wherein the photosensitive component is a photobase generator.   7. The thin film transistor substrate according to claim 5, wherein the base generated in the photobase generator is an aliphatic amine or amidine.   8. The thin film transistor substrate according to claim 5, wherein a 5% weight reduction temperature of the photobase generator is in a range of 150 ° C. to 300 ° C. 9. The thin film transistor substrate according to any one of claims 5 to 8, wherein the photobase generator is represented by the following formula.

(In Formula (a), R ²¹ and R ²² are each independently hydrogen or a monovalent organic group, and may be the same or different. R ²¹ and R ²² are bonded to each other. May form a cyclic structure and may contain a heteroatom bond, provided that at least one of R ²¹ and R ²² is a monovalent organic group R ²³ , R ²⁴ , R ²⁵ And R ²⁶ , each independently, hydrogen, halogen, hydroxyl group, mercapto group, sulfide group, silyl group, silanol group, nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonato group, an amino group, an ammonio group or a monovalent organic group, may be different even in the same ^{.R 23, R 24,} R ²⁵ and ^{R 26,} those two or more binding May form a cyclic structure Te may, may contain a binding heteroatom.)   At least one of the gate insulating layer in the top gate type thin film transistor or the gate insulating layer and the passivation layer in the bottom gate type thin film transistor among the semiconductor layer contact insulating layer is at least the photosensitive polyimide insulating layer. The thin film transistor substrate according to claim 1, wherein the thin film transistor substrate is a thin film transistor substrate.   The gate insulating layer in the top gate type thin film transistor or the passivation layer in the bottom gate type thin film transistor among the semiconductor layer contact insulating layers is at least the photosensitive polyimide insulating layer. The thin film transistor substrate according to 1.   The said board | substrate is a flexible substrate which has a metal foil and the planarization layer which is formed on the said metal foil and contains a polyimide, The claim in any one of Claim 1-11 characterized by the above-mentioned. Thin film transistor substrate.   The thin film transistor substrate according to claim 12, wherein the flexible substrate has an adhesion layer containing an inorganic compound on the planarizing layer.

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