WO2023190861A1

WO2023190861A1 - Vapor deposition mask

Info

Publication number: WO2023190861A1
Application number: PCT/JP2023/013165
Authority: WO
Inventors: 義和大塚; 智久山田; 大輔前田
Original assignee: 日産化学株式会社
Priority date: 2022-03-30
Filing date: 2023-03-30
Publication date: 2023-10-05
Also published as: JP2023149108A; JP7131728B1

Abstract

Provided is a vapor deposition mask in which thermal deformation is inhibited. An embodiment of the present invention is a vapor deposition mask 10. The vapor deposition mask 10 is provided with a resin layer 24 having a pattern of opening parts for forming a thin film pattern, by vapor deposition, on a substrate subject to vapor deposition. The resin layer 24 contains a polyamic acid-derived polyimide including structural units represented by formula (1). In formula (1), X¹ represents at least one tetravalent organic acid selected from formulas (3) and (3'), Y¹ represents an F-containing organic group or a group represented by formula (P), and n is a positive integer representing the number of structural units. In formula (3'), R¹⁰, R¹¹, R¹², and R¹³ independently represent a hydrogen atom or a C1-3 monovalent alkyl group.　In formula (P), R represents Cl, a C1-3 alkyl group, or a phenyl group. In formula (P), m represents an integer of 0-4, and r represents an integer of 1-3.

Description

vapor deposition mask

The present invention relates to a vapor deposition mask.

In the manufacturing process of an organic EL display device, a vapor deposition mask is used to stack necessary organic layers only on necessary pixels on a device substrate on which switch elements such as TFTs are formed. Conventionally, a metal mask has been used as the vapor deposition mask, but in recent years, in order to form a finer pattern of mask openings, there is a tendency to use a resin film as a mask material instead of a metal mask.
Furthermore, as products become larger or device substrates become larger, there is a demand for larger vapor deposition masks, and resin films are attracting attention as mask materials from the viewpoint of weight reduction.

Unexamined Japanese Patent Publication No. 2017-14620

Resin films conventionally used as mask materials are required to further reduce their coefficient of linear expansion from the viewpoint of suppressing thermal deformation.
The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a vapor deposition mask in which thermal deformation is suppressed.

An embodiment of the present invention is a vapor deposition mask. A resin layer having a pattern of openings for forming a thin film pattern by vapor deposition on a substrate to be vapor-deposited, the resin layer containing polyimide derived from polyamic acid containing a structural unit represented by the following formula (1). .

In formula (1), X ¹ represents at least one tetravalent organic group selected from formulas (3) and (3') below, and Y ¹ represents a group represented by formula (P) below. or represents an F-containing organic group, and n is a positive integer representing the number of repeating units.

In formula (3'), R ¹⁰ , R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a monovalent alkyl group having 1 to 3 carbon atoms.
In formula (P), R represents Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group. Further, in formula (P), m represents an integer of 0 to 4, and r represents an integer of 1 to 3.

The vapor deposition mask of the above aspect may further include a metal layer laminated on at least a portion of the surface of the resin layer facing the vapor deposition source. Moreover, the resin layer may contain silica particles. Further, the surface of the silica particles may be modified with an alkoxysilane compound having two aromatic groups having 6 to 18 carbon atoms or one aromatic group having 7 to 18 carbon atoms.

According to the present invention, a technique related to a vapor deposition mask in which thermal deformation is suppressed is provided.

FIG. 1(a) is a plan view of the vapor deposition mask according to Embodiment 1 when viewed from the resin layer side, and FIG. 1(b) is a cross-sectional view taken along line AA shown in FIG. 1(a). It is.

Hereinafter, embodiments of the present invention will be described in detail. In addition, in this specification, the notation "a to b" in the description of numerical ranges represents a range from a to b, unless otherwise specified.

(vapor deposition mask)
FIG. 1(a) is a plan view of the vapor deposition mask 10 according to the embodiment when viewed from the resin layer 24 side, and FIG. 1(b) is a cross-sectional view taken along line AA shown in FIG. 1(a). It is a diagram.

The vapor deposition mask 10 includes a plurality of mask bodies 20 and a reinforcing frame 30 disposed around the plurality of mask bodies 20 so as to surround the plurality of mask bodies 20. The frame body 30 fixes and holds the mask body 20 in a tensioned state.

The mask body 20 is a hybrid mask in which a metal layer 22 is laminated on the main surface side of a resin layer 24 facing the vapor deposition source. In the mask body 20, an opening P for forming a thin film pattern on the substrate to be deposited by vapor deposition is provided in the resin layer 24, and a through hole Q containing the opening P is formed in the metal layer 22. There is.

The material of the metal layer 22 is not particularly limited, but stainless steel, iron-nickel alloy, aluminum alloy, etc. are applicable, for example. In particular, Invar alloy, which is an alloy mainly composed of iron and nickel, has a relatively small coefficient of linear expansion and is preferable from the viewpoint of suppressing thermal deformation. The metal layer 22 and the frame 30 are bonded to each other at a portion in contact with the frame 30.

The material of the resin layer 24 will be described later.

The frame body 30 is formed of a metal plate material having a low coefficient of linear thermal expansion. Examples of the metal plate material constituting the frame 30 include Invar material, which is a nickel-iron alloy, and Super Invar material, which is a nickel-iron-cobalt alloy.

(Method for manufacturing a vapor deposition mask)
An example of a method for manufacturing a vapor deposition mask according to an embodiment will be described below.
First, the resin layer 24 is laminated on the metal layer 22 in the form of metal foil. Examples of the lamination method include a method of pasting the resin layer 24 on the metal layer 22 and a method of forming the metal layer 22 on the resin layer 24 by plating.
After applying a resist (not shown) to the main surface of the metal layer 22 opposite to the resin layer 24, exposure and development are performed to form through-holes Q in the metal layer 22. The corresponding part is removed.
Subsequently, the portions of the metal layer 22 that are exposed in the portions where the resist has been removed are selectively removed by an etching process, thereby forming through-holes Q in a predetermined pattern in the metal layer 22.
Subsequently, the mask body 20 is formed by irradiating a region of the resin layer 24 included in the through hole Q with a laser beam to form a predetermined pattern of openings P.
The obtained mask main body 20 is aligned with the frame 30, and the metal layer 22 and the frame 30 are joined at the portions that contact the frame 30. The method of joining the metal layer 22 and the frame body 30 is not particularly limited, but examples thereof include a method of joining with an adhesive, a method of joining by welding, and the like.

(Resin composition for vapor deposition mask)
The resin composition for a vapor deposition mask used to form the resin layer 24 will be explained.
The resin composition for a vapor deposition mask according to the embodiment includes a polyamic acid containing a structural unit represented by formula (1) and an organic solvent.

In formula (1), X ¹ represents a tetravalent aromatic group of formula (3), and Y ¹ represents a group represented by formula (P).

In formula (1), X ¹ represents at least one tetravalent organic group selected from formulas (3) and (3') below, and Y ¹ represents a group represented by formula (P) below. or represents an F-containing organic group, and n is a positive integer representing the number of repeating units, and is determined according to the weight average molecular weight of the polyamic acid used in this embodiment.

In formula (3'), R ¹⁰ , R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a monovalent alkyl group having 1 to 3 carbon atoms.
Further, in formula (P), R represents Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, and preferably represents F or Cl. Furthermore, in formula (P), m represents an integer of 0 to 4, preferably 0 to 2, more preferably 0 to 1, particularly preferably 0. Furthermore, in the above formula (P), r represents an integer of 1 to 3.
Note that the alkyl group having 1 to 3 carbon atoms includes methyl, ethyl, n-propyl, and i-propyl, preferably the alkyl group having 1 to 3 carbon atoms is methyl, and more preferably, It is methyl.

The weight average molecular weight of the polyamic acid having the repeating unit represented by formula (1) used in this embodiment is preferably 10,000 or more, more preferably 15,000 or more, even more preferably 20,000 or more, 30, 000 or more is even more preferable. On the other hand, the upper limit of the weight average molecular weight of the polyamic acid used in this embodiment is usually 2,000,000 or less, but it is important to prevent the viscosity of the resin composition (varnish) for a vapor deposition mask from becoming excessively high. In consideration of obtaining reproducibly, it is preferably 1,000,000 or less, more preferably 200,000 or less. In addition, in this specification, the weight average molecular weight is obtained by measuring by gel permeation chromatography (GPC) and converting it using a calibration curve prepared using standard polystyrene.

The polyamic acid used in this embodiment contains repeating units represented by formula (1) at least 50 mol%, preferably at least 60 mol%, more preferably at least 70 mol%, even more preferably at least 80 mol%, More preferably, the content is at least 90 mol%. By using polyamic acid in such an amount, a resin layer having characteristics suitable for a vapor deposition mask can be obtained with good reproducibility.

According to a preferred aspect of the present embodiment, the polyamic acid is a copolymer made only of repeating units represented by formula (1), that is, a polymer containing 100 mol% of these repeating units. At this time, the structural unit represented by formula (1) in this polyamic acid is not composed of only one specific type of repeating units represented by formula (1), but is composed of two or more types of repeating units represented by formula (1). It is preferable to have a random or block copolymer structure consisting of repeating units of ). The types of repeating units of formula (1) that can be used are preferably 2 to 4, and even more preferably 2 to 3.

According to a preferred aspect of the present embodiment, the resin composition for a vapor deposition mask is a polyamic acid containing structural units represented by formulas (1-1) and (1-2), and whose weight average molecular weight is 10,000 or more, and an organic solvent.

In formula (1-1) and formula (1-2), X ¹ represents at least one tetravalent organic group selected from the above formulas (3) and (3'), and Y ² represents the above-mentioned It represents a group represented by formula (P1) or (P2), preferably represents a group represented by formula (P1), and Y ³ represents a group represented by formula (P3) above.

In formula (P1), formula (P2) and formula (P3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different, and F, Cl, Represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, preferably F or Cl. Furthermore, m1, m2, m3, m4, m5 and m6 may be the same or different and represent an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1. , particularly preferably 0.
Furthermore, in formulas (1-1) and (1-2), n1 and n2 indicate the number of each repeating unit, and satisfy the condition of n1/n2=1.7 to 20. Here, the lower limit of the numerical range of n1/n2 is preferably 2.1, more preferably 2.2, and even more preferably 2.3. On the other hand, the upper limit of the numerical range of n1/n2 is preferably 19, more preferably 18.
Considering that a resin layer having an appropriate coefficient of linear expansion, heat resistance, and tensile strength can be obtained with good reproducibility, n1/n2 preferably satisfies 2.1 to 7.5, and preferably 2.1 to 6.8. More preferably, it satisfies 3.2 to 6.0, even more preferably 3.2 to 5.1.

The polyamic acid used in this embodiment contains repeating units represented by formula (1-1) and formula (1-2) at least 50 mol%, preferably at least 60 mol%, more preferably at least 70 mol%, Even more preferably it contains at least 80 mol%, and even more preferably at least 90 mol%. By using polyamic acid in such an amount, a resin layer having characteristics suitable for a vapor deposition mask can be obtained with good reproducibility.

According to a particularly preferred aspect of this embodiment, the polyamic acid is a copolymer made only of the repeating units represented by formula (1-1) and formula (1-2), that is, the polyamic acid contains 100 mol% of these repeating units. It is a polymer that

The weight average molecular weight of the polyamic acid used in this embodiment needs to be 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and even more preferably 30,000 or more. On the other hand, the upper limit of the weight average molecular weight of the polyamic acid used in this embodiment is usually 2,000,000 or less, but it is important to prevent the viscosity of the resin composition (varnish) for a vapor deposition mask from becoming excessively high. In consideration of obtaining a resin layer with high tensile strength and high reproducibility, etc., it is preferably 1,000,000 or less, more preferably 200,000 or less.

According to a more preferred aspect of this embodiment, the polyamic acid can further include a structural unit represented by formula (2).

In formula (2), X ¹ represents at least one tetravalent organic group selected from the above formulas (3) and (3'), and Y ⁴ represents a group represented by the following formula (P4). and n ³ represents the number of repeating units.

In formula (P4), R ⁷ and R ⁸ may be the same or different and represent F, Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group. R ⁷ preferably represents F or Cl. R ⁸ preferably represents F or Cl. R' represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom. Furthermore, l and m may be the same or different and represent an integer of 0 to 4, preferably 0 to 2, more preferably 0 to 1, particularly preferably 0.

When the structural unit represented by formula (2) is included in addition to the structural unit represented by formula (1), n and n3 are preferably n3/(n+n3)≦0.2, more preferably n3/ (n+n3)≦0.1, more preferably n3/(n+n3)≦0.05. This range is advantageous in obtaining a resin layer with appropriate linear expansion coefficient, heat resistance, and tensile strength with good reproducibility.

In addition to the structural units represented by formulas (1-1) and (1-2), when the structural unit represented by formula (2) is included, n1, n2, and n3 are preferably n3/(n1+n2+n3 )≦0.2, more preferably n3/(n1+n2+n3)≦0.1, even more preferably n3/(n1+n2+n3)≦0.05. This range is advantageous in obtaining a resin layer with appropriate linear expansion coefficient, heat resistance, and tensile strength with good reproducibility.

The polyamic acid used in this embodiment has other structural units (repeating unit). The content of such other structural units must be less than 50 mol%, preferably less than 40 mol%, more preferably less than 30 mol%, and less than 20 mol%. is even more preferable, and even more preferably less than 10 mol%.

Such other structural units include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 5-methyl-1,3-phenylenediamine, 4-methyl -1,3-phenylenediamine, 2-(trifluoromethyl)-1,4-phenylenediamine, 2-(trifluoromethyl)-1,3-phenylenediamine and 4-(trifluoromethyl)-1,3- Phenylenediamine, benzidine, 2,2'-dimethylbenzidine, 3,3'-dimethylbenzidine, 2,3'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-bis(trifluoromethyl)benzidine, fluoromethyl)benzidine, 2,3'-bis(trifluoromethyl)benzidine, 4,4'-diphenyl ether, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diaminobenzanilide, 5- Diamines such as amino-2-(3-aminophenyl)-1H-benzimidazole, 9,9-bis(4-aminophenyl)fluorene, pyromellitic anhydride (PMDA), 2,3,6,7-naphthalene Examples include structures derived from acid dianhydrides such as tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 3,3',4,4'-benzophenone tetracarboxylic anhydride.

According to a preferred aspect of this embodiment, the polyamic acid used in this embodiment is 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) (formula (4)) as an acid dianhydride. ) with p-phenylenediamine (pPDA) (formula (5)) and 4,4''-diamino-p-terphenyl (DATP) (formula (6)) as diamines. can.

In the above reaction, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), p-phenylenediamine (pPDA) and 4,4''-diamino-p-terphenyl (DATP) are used. The charging ratio (mole ratio) of the diamine can be set as appropriate by taking into consideration the molecular weight of the desired polyamic acid, the ratio of structural units, etc. It can be about .7 to 1.3, preferably about 0.8 to 1.2.

On the other hand, the charging ratio of pPDA and DATP, which are diamines, can be such that when the amount of DATP (m ² ) is 1, the amount of pPDA (m ¹ ) is usually about 1.7 to 20. is preferably 2.1 to 20, more preferably 2.2 to 20, even more preferably 2.3 to 19, even more preferably 2.3 to 18. That is, m ¹ and m ² are usually m ¹ /m ² = 1.7 to 20, preferably 2.1 to 20, more preferably 2.2 to 20, even more preferably It is 2.3 to 19, more preferably 2.3 to 18.

According to a more preferred aspect of the present embodiment, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) as the acid dianhydride and p-phenylenediamine (pPDA) as the diamine. and 4,4”-diamino-p-terphenyl (DATP) and further react with 2-(3-aminophenyl)-5-aminobenzimidazole (APAB) (formula (7)). can.

In the above reaction, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), p-phenylenediamine (pPDA), 4,4''-diamino-p-terphenyl (DATP) and 2 The charging ratio (molar ratio) of the diamine consisting of -(3-aminophenyl)-5-aminobenzimidazole (APAB) can be appropriately set in consideration of the desired molecular weight of the polyamic acid, the ratio of structural units, etc. However, the amount of BPDA, which is an acid anhydride component, can be generally adjusted to about 0.7 to 1.3, preferably about 0.8 to 1.2, relative to the amine component 1.

On the other hand, the preparation ratio of the diamines pPDA, DATP, and APAB is as follows, assuming that the sum of the amount of pPDA (m ¹ ), the amount of DATP (m ² ), and the amount of APAB (m ³ ) is 1. The amount (m ³ ) of APAB is preferably 0.2 or less, more preferably 0.1 or less, even more preferably 0.05 or less. That is, m ¹ , m ² and m ³ are preferably m ³ /(m ¹ +m ² +m ³ )≦0.2, more preferably m ³ /(m ¹ +m ² +m ³ )≦0.1. , more preferably satisfies m3/(m1+m2+m3)≦0.05.

The above-mentioned reaction is preferably carried out in a solvent, and when a solvent is used, various types of solvents can be used as long as they do not adversely affect the reaction.
Specific examples include m-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide. , 3-methoxy-N,N-dimethylpropylamide, 3-ethoxy-N,N-dimethylpropylamide, 3-propoxy-N,N-dimethylpropylamide, 3-isopropoxy-N,N-dimethylpropylamide, Protic solvents such as 3-butoxy-N,N-dimethylpropylamide, 3-sec-butoxy-N,N-dimethylpropylamide, 3-tert-butoxy-N,N-dimethylpropylamide, γ-butyrolactone, etc. Can be mentioned. These may be used alone or in combination of two or more.

The reaction temperature may be appropriately set within the range from the melting point to the boiling point of the solvent used, and is usually about 0 to 100°C, but it is necessary to prevent imidization of the resulting polyamic acid and maintain a high content of polyamic acid units. For this purpose, the temperature is preferably about 0 to 70°C, more preferably about 0 to 60°C, even more preferably about 0 to 50°C.
Although the reaction time cannot be absolutely defined because it depends on the reaction temperature and the reactivity of the raw materials, it is usually about 1 to 100 hours.

By the method explained above, a reaction solution containing the desired polyamic acid can be obtained.

In this embodiment, the reaction solution is usually filtered, and then the filtrate is used as it is, or after being diluted or concentrated, as a resin composition (varnish) for a vapor deposition mask. By doing so, it is possible not only to reduce the incorporation of impurities that may cause deterioration of the heat resistance, tensile strength, or linear expansion coefficient characteristics of the resulting resin layer, but also to efficiently obtain the composition.
The solvent used for dilution and concentration is not particularly limited, and examples include those similar to the specific examples of the reaction solvent for the above reaction, and they may be used alone or in combination of two or more. .

Among these, in order to obtain a highly flat resin layer with good reproducibility, the solvents used are N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3 -dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, and γ-butyrolactone are preferred.

In addition, in this embodiment, after post-processing the above reaction solution according to a conventional method to isolate polyamic acid, a varnish obtained by dissolving or dispersing the isolated polyamic acid in an organic solvent is used as a vapor deposition mask. It may also be used as a resin composition. In this case, in order to obtain a highly flat thin film with good reproducibility, it is preferable that the polyamic acid is dissolved in an organic solvent. The organic solvent used for dissolution and dispersion is not particularly limited, and examples thereof include those similar to the specific examples of the reaction solvent for the above reaction, and they may be used alone or in combination of two or more. good.

The concentration of polyamic acid relative to the total mass of the varnish should be set appropriately taking into account the thickness of the thin film to be produced, the viscosity of the varnish, etc., but it is usually about 0.5 to 30 mass%, preferably about 5 to 25 mass%. be.

In addition, the viscosity of the varnish should be set appropriately considering the thickness of the thin film to be produced, etc., but when the purpose is to obtain a resin layer with a thickness of about 5 to 50 μm with good reproducibility, it is usually heated at 25°C. It is about 500 to 50,000 mPa·s, preferably about 1,000 to 20,000 mPa·s.
Here, the viscosity of the varnish can be measured using a commercially available viscometer for measuring the viscosity of liquids, for example, with reference to the procedure described in JIS K7117-2, and at a varnish temperature of 25°C. . Preferably, a cone-plate rotational viscometer is used as the viscometer, preferably using the same type of viscometer with a standard cone rotor of 1°34'×R24, and a varnish temperature of 25°C. It can be measured under certain conditions. An example of such a rotational viscometer is TVE-25H manufactured by Toki Sangyo Co., Ltd.

By applying the resin composition for a vapor deposition mask of this embodiment described above to the metal layer 22 and heating it, a resin layer 24 containing polyimide having high heat resistance and a low coefficient of linear expansion can be obtained. The coefficient of linear expansion of the resin layer 24 is preferably 3 ppm/K or less, more preferably 2 ppm/K or less, and even more preferably 1 ppm/K or less.

(Silica particles)
The resin composition for a vapor deposition mask of this embodiment contains silica (silicon dioxide) particles or silica particles whose surfaces are modified with a specific alkoxysilane (hereinafter sometimes referred to as surface-modified silica particles) as other components. It is preferable to include.
The average particle diameter of the silica particles and surface-modified silica particles can be appropriately selected depending on the purpose and the like. Among them, the average particle diameter is preferably 1 nm to 100 nm, more preferably 1 nm to 60 nm, even more preferably 9 nm to 60 nm, and even more preferably 9 nm to 45 nm, from the viewpoint of obtaining a highly transparent thin film. It is particularly preferable.
In addition, in this specification, the average particle diameter of silica particles and surface-modified silica particles is an average particle diameter value calculated from specific surface area values measured by a nitrogen adsorption method using silica particles and surface-modified silica particles, respectively. be.

As the silica particles, for example, colloidal silica having the above average particle diameter value can be suitably used, and as the colloidal silica, silica sol can be used. As the silica sol, it is possible to use an aqueous silica sol produced by a known method using an aqueous sodium silicate solution as a raw material, and an organosilica sol obtained by replacing water, which is a dispersion medium of the aqueous silica sol, with an organic solvent.
In addition, alkoxysilanes such as methyl silicate and ethyl silicate are hydrolyzed in an organic solvent such as alcohol in the presence of a catalyst (e.g., ammonia, an organic amine compound, an alkali catalyst such as sodium hydroxide) and condensed. It is also possible to use silica sol, or organosilica sol obtained by substituting the silica sol with another organic solvent.
Among these, in this embodiment, it is preferable to use an organosilica sol whose dispersion medium is an organic solvent.

Examples of the organic solvent in the above organosilica sol include lower alcohols such as methyl alcohol, ethyl alcohol, and isopropanol; linear amides such as N,N-dimethylformamide and N,N-dimethylacetamide; N-methyl-2- Examples include cyclic amides such as pyrrolidone; ethers such as γ-butyrolactone; glycols such as ethyl cellosolve and ethylene glycol; and acetonitrile.
Replacement of water, which is the dispersion medium of the aqueous silica sol, or replacement with another desired organic solvent can be carried out by a conventional method such as distillation or ultrafiltration.
The viscosity of the above organosilica sol is about 0.6 mPa·s to 100 mPa·s at 20°C.

Examples of commercial products of the organosilica sol include, for example, the product name MA-ST-S (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd. (currently Nissan Chemical Co., Ltd., hereinafter the same)), and the product name MT-ST. (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MA-ST-UP (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), product name MA-ST-M (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.) Co., Ltd.), product name MA-ST-L (methanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), product name IPA-ST-S (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), product name IPA-ST (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name IPA-ST-UP (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name IPA-ST-L (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.) (manufactured by Nissan Chemical Industries, Ltd.), trade name IPA-ST-ZL (isopropanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name NPC-ST-30 (n-propyl cellosolve-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.) ), trade name PGM-ST (1-methoxy-2-propanol-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name DMAC-ST (dimethylacetamide-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), product Product name: XBA-ST (silica sol dispersed in xylene/n-butanol mixed solvent, manufactured by Nissan Chemical Industries, Ltd.), Product name: EAC-ST (Silica sol dispersed in ethyl acetate, manufactured by Nissan Chemical Industries, Ltd.), Product name: PMA-ST ( Propylene glycol monomethyl ether acetate-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MEK-ST (methyl ethyl ketone-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), trade name MEK-ST-UP (methyl ethyl ketone-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.) (manufactured by Kogyo Co., Ltd.), trade name MEK-ST-L (methyl ethyl ketone-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.) and trade name MIBK-ST (methyl isobutyl ketone-dispersed silica sol, manufactured by Nissan Chemical Industries, Ltd.), PL. -1-IPA (isopropanol-dispersed silica sol, manufactured by Fuso Chemical Industries, Ltd.), PL-1-TOL (toluene-dispersed silica sol, manufactured by Fuso Chemical Industries, Ltd.), PL-2L-PGME (propylene glycol monomethyl ether-dispersed silica sol, PL-2L-MEK (methyl ethyl ketone dispersed silica sol, manufactured by Fuso Chemical Industry Co., Ltd.), PL-3-ME (methanol dispersed silica sol, manufactured by Fuso Chemical Industry Co., Ltd.), etc. However, it is not limited to these.
In this embodiment, silicon dioxide, for example, the silicon dioxides listed in the above products used as organosilica sol, may be used in combination of two or more types.

In this embodiment, the alkoxysilane compound (hereinafter referred to as a specific alkoxysilane) used to modify inorganic fine particles is an alkoxysilane compound having two aromatic groups having 6 to 18 carbon atoms, or an alkoxysilane compound having 2 aromatic groups having 6 to 18 carbon atoms, or having 7 to 18 carbon atoms. Examples include alkoxysilane compounds having one 18 aromatic group.
Examples of the aromatic group having 6 to 18 carbon atoms include a phenyl group and an aromatic group having 7 to 18 carbon atoms, which will be described later. Examples of the aromatic group having 7 to 18 carbon atoms include a group having two to three benzene rings and a group having two to four condensed benzene rings. Among these, an alkoxysilane having a structure represented by the following formula (S1) and having a biphenyl group as an aromatic group having 7 to 18 carbon atoms is preferable.

In formula (S1), R ¹ and R ² are each independently an alkyl group having 1 to 3 carbon atoms, W is an integer of 1 to 3, Y is an integer of 0 to 2, and , W+Y=3, Z ¹ represents a group selected from the group consisting of a halogen atom, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms, and m is an integer of 0 to 5. where m is an integer of 2 or more, Z ¹ may be the same or different groups. Among these, alkoxysilanes in which m is 0 (biphenyl group is not substituted) are preferred.

Examples of the alkoxysilane compound represented by the above formula (S1) include 4-biphenyltrimethoxysilane, 4-biphenyltriethoxysilane, 3-biphenyltrimethoxysilane, and 3-biphenyltriethoxysilane.

Silica particles whose surfaces are modified with a specific alkoxysilane can be prepared by bringing the specific alkoxysilane and silica particles into contact. When a specific alkoxysilane and silica particles are brought into contact, for example, the silanol group or alkoxysilyl group in the specific alkoxysilane undergoes a condensation reaction and bonds with the hydroxyl group present on the surface of the silica particle, and the surface is modified with the specific alkoxysilane. It is thought that silica particles are formed.
Specifically, for example, silica particles whose surfaces are modified with a specific alkoxysilane can be prepared by mixing a colloidal solution of silica particles and a specific alkoxysilane solution prepared in advance. The colloidal solution and the specific alkoxysilane solution may be mixed at room temperature or while being heated. From the viewpoint of reaction efficiency, it is preferable to perform the mixing while heating. When mixing is performed while heating, the heating temperature can be appropriately selected depending on the solvent and the like. The heating temperature can be, for example, 60° C. or higher, and is preferably the reflux temperature of the solvent.

The mixing ratio of the specific alkoxysilane and silica particles can be appropriately selected depending on the purpose and the like. For example, the mass ratio of silica particles to specific alkoxysilane (silica particles/specific alkoxysilane) is preferably 70/30 to 99/1, more preferably 70/30 to 90/10, and 80/30 to 99/1. More preferably, the ratio is 20 to 90/10. Here, the mass number of the silica particles is calculated assuming that the compositional formula of the silica particles is SiO2.

In the resin composition for a vapor deposition mask of the present embodiment, the content of the silica particles or surface-modified silica particles is 20 to 100 parts by mass based on 100 parts by mass of the polyamic acid containing the structural unit represented by formula (1). It is preferably 20 to 80 parts by weight, more preferably 30 to 70 parts by weight. By setting the content of silica particles or surface-modified silica particles within the above range, the strength can be further increased without impairing the linear expansion coefficient of the resin layer obtained using the resin composition for a vapor deposition mask.

When the resin composition for a vapor deposition mask of this embodiment contains silica particles or surface-modified silica particles, the polyimide suitably used in the resin composition for a vapor deposition mask preferably contains fluorine. According to this, the compatibility between polyimide and silica particles or surface-modified silica particles can be improved. As a result, aggregation of the silica particles or surface-modified silica particles can be suppressed, and good dispersibility of the silica particles or surface-modified silica particles can be maintained in the resin layer obtained using the resin composition for a vapor deposition mask.
For example, Y ¹ in formula (1) may be a divalent group selected from the group consisting of formulas (Y-1) to (Y-34) below.

In formulas (Y-1) to (Y-34), * represents a bond.

Methods for imidizing the polyamic acid contained in the resin composition for a vapor deposition mask of this embodiment include thermal imidization in which the resin composition for a vapor deposition mask coated on the metal layer 22 is directly heated, and the resin composition for a vapor deposition mask One example is catalytic imidization, in which a catalyst is added to a substance and heated.

In the case of catalytic imidization of polyamic acid, a catalyst is added to the resin composition for a vapor deposition mask of this embodiment, and the resin composition for a vapor deposition mask to which the catalyst has been added is prepared by stirring, and then the metal layer is A resin layer 24 is obtained by coating the resin layer 22 and heating it. The amount of catalyst is 0.1 to 30 times the amount of the amic acid group, preferably 1 to 20 times the amount by mole. Furthermore, acetic anhydride or the like can be added as a dehydrating agent to the resin composition for a vapor deposition mask to which a catalyst has been added, and the amount thereof is 1 to 50 times, preferably 3 to 30 times by mole, the amount of the amic acid group.

It is preferable to use a tertiary amine as the imidization catalyst. Preferred tertiary amines include pyridine, substituted pyridines, imidazole, substituted imidazoles, picoline, quinoline, and isoquinoline.

The heating temperature during thermal imidization and catalyst imidization is preferably 450° C. or lower. If the temperature exceeds 450°C, the resin layer obtained becomes brittle, and it may not be possible to obtain a resin layer suitable for use as a vapor deposition mask.
In addition, considering the heat resistance and linear expansion coefficient characteristics of the resin layer obtained, it is possible to heat the applied resin composition for a vapor deposition mask at 50°C to 100°C for 5 minutes to 2 hours, and then gradually increase the heating temperature. It is desirable to finally heat the mixture at a temperature of over 375°C to 450°C for 30 minutes to 4 hours.
In particular, the applied resin composition for a vapor deposition mask is heated at 50°C to 100°C for 5 minutes to 2 hours, then heated at over 100°C to 200°C for 5 minutes to 2 hours, and then heated at over 200°C to 375°C for 5 minutes to 2 hours. Preferably, the mixture is heated for 30 minutes to 2 hours and finally at a temperature of more than 375° C. to 450° C. for 30 minutes to 4 hours.
Examples of appliances used for heating include hot plates and ovens. The heating atmosphere may be under air or inert gas, and may be under normal pressure or reduced pressure.

The thickness of the resin layer 24, especially when used as a vapor deposition mask, is usually about 1 to 60 μm, preferably about 5 to 50 μm, and the thickness of the coating before heating can be adjusted to obtain a resin layer of a desired thickness. Form.

The resin layer 24 described above satisfies each condition necessary for a vapor deposition mask, and in particular has an extremely low coefficient of linear expansion of 3 ppm/K, so it is optimal for use as a vapor deposition mask with suppressed thermal deformation.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

Although the frame 30 of the embodiment described above has a frame-like shape with an opening, a horizontal frame or a vertical frame may be formed in the opening, and the metal layer 22 may be bonded to the horizontal frame or vertical frame. . According to this, the strength of the mask body 20 due to the frame body 30 can be increased, and in turn, the mask body 20 can be prevented from bending, and the flatness can be increased.

Further, in the embodiment described above, the metal layer 22 and the resin layer 24 are laminated in the entire mask body 20, but the metal layer 22 is laminated on a part of the resin layer 24, and the other parts of the resin layer 24 are laminated. The portion may be used alone as a mask.

10 Vapor deposition mask, 20 Mask body, 22 Metal layer, 24 Resin layer, 30 Frame

Claims

a resin layer having a pattern of openings for forming a thin film pattern by vapor deposition on a substrate to be vapor-deposited;
A vapor deposition mask, wherein the resin layer contains polyimide derived from polyamic acid containing a structural unit represented by the following formula (1).

In formula (1), X 1 represents at least one tetravalent organic group selected from formulas (3) and (3') below, and Y 1 represents a group represented by formula (P) below. or represents an F-containing organic group, and n is a positive integer representing the number of repeating units.

In formula (3'), R 10 , R 11 , R 12 and R 13 each independently represent a hydrogen atom or a monovalent alkyl group having 1 to 3 carbon atoms.
In formula (P), R represents Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group. Further, in formula (P), m represents an integer of 0 to 4, and r represents an integer of 1 to 3.
The vapor deposition mask according to claim 1, further comprising a metal layer laminated on at least a portion of the surface of the resin layer facing the vapor deposition source.
The vapor deposition mask according to claim 1 or 2, wherein the resin layer contains silica particles.
According to claim 3, the surface of the silica particles is modified with an alkoxysilane compound having two aromatic groups having 6 to 18 carbon atoms or one aromatic group having 7 to 18 carbon atoms. Vapor deposition mask as described.