Alkali-developable polymer and alkali-developable polymer composition

Abstract

To provide an alkali-developable polymer that facilitates high-definition patterning, offers superior curability and developability, enables the formation of a cured product with superior hardness and heat resistance, and allows for easy development even with a low-concentration alkali developer.SOLUTION: Provided is an alkali-developable polymer including a polymer chain A and a polymer chain B with a number average molecular weight of 7,000-20,000, a molecular weight distribution of 1.2-1.8, an acid value of 40-100 mg / KOH, and an unsaturated group equivalent of 900-3,000 g / mol. This polymer is a reaction product resulting from the reaction of an A'B' block copolymer, having a number average molecular weight of 6,000-18,000, a molecular weight distribution of 1.1-1.7, and an acid value of 70-130 mgKOH / g, with an epoxy group-containing (meth)acrylate.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an alkali-developable polymer and an alkali-developable polymer composition.

Background Art

[0002] An alkali-developable polymer is used as a patterning material such as a photoresist when manufacturing printed wiring boards, semiconductor packages, insulating films, printing plates, spacers for liquid crystal cells, color filters, black matrices, and the like. An alkali-developable polymer is a polymer used to cure the exposed portion irradiated with ultraviolet rays and dissolve and develop the unexposed portion not irradiated with ultraviolet rays with an alkali.

[0003] As such alkali-developable polymers, various polymers having improved properties such as developability, heat resistance, and patterning properties have been developed (Patent Documents 1 to 3). For example, a curable polymer in which a radically polymerizable double bond is introduced into a polymer synthesized from a monomer formulation containing a maleimide-based monomer, acrylic acid, and an acrylate ester but not containing methacrylic acid and its ester has been proposed (Patent Document 1). Further, an alkali-developable resin obtained using an epoxy resin, an unsaturated monocarboxylic acid, an unsaturated monocarboxylic acid anhydride, and a dicarboxylic acid anhydride has been proposed (Patent Document 2). Furthermore, an alkali-developable resin obtained by further reacting a polybasic acid anhydride with the hydroxyl group of a product obtained by reacting a compound having a hydroxyl group and an epoxy group with the hydroxyl group of a phenol resin has been proposed (Patent Document 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, further high-precision patterning has been required, and further improvement in the durability and heat resistance of the cured product obtained by patterning has been demanded. Also, in order to improve productivity, a resin that can be developed more quickly has been sought. Furthermore, from the viewpoints of cost and environmental load, etc., a resin that can be easily developed even with a low-concentration alkaline developer has been required. And, a composition containing such a developable resin and suppressing the amount of outgas generated before and after curing of the resin as much as possible has been demanded.

[0006] The present invention has been made in view of such problems of the prior art, and the problem to be solved is that high-precision patterning is possible, the curing characteristics and developability are good, and a cured product excellent in hardness and heat resistance can be formed, and it can be easily developed even when using a low-concentration alkaline developer. That is, to provide an alkali-developable polymer. Furthermore, the problem to be solved by the present invention is to provide an alkali-developable polymer composition containing this alkali-developable polymer and suppressing the generation of outgas.

Means for Solving the Problems

[0007] That is, according to the present invention, an alkali-developable polymer shown below is provided. [1] An alkali-developable polymer which is a reaction product obtained by reacting an A'B' block copolymer satisfying the following requirements (1) to (3) with an epoxy group-containing (meth)acrylate, having a number average molecular weight of 7,000 to 20,000, a molecular weight distribution (weight average molecular weight / number average molecular weight) of 1.2 to 1.8, an acid value of 40 to 100 mg / KOH, and an unsaturated group equivalent of 900 to 3,000 g / mol, and containing a polymer chain A and a polymer chain B. [Requirement (1)] A block copolymer containing polymer chains A' and B', having a number average molecular weight of 6,000 to 18,000, a molecular weight distribution of 1.1 to 1.7, and an acid value of 70 to 130 mgKOH / g. [Requirement (2)] The polymer chain A' contains 15 to 55% by mass of structural unit (i-a) derived from at least one monomer selected from the group consisting of methyl methacrylate and benzyl methacrylate, 15 to 60% by mass of structural unit (ii-a) derived from at least one monomer selected from the group consisting of cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate, 5 to 30% by mass of structural unit (iii-a) derived from a methacrylate having a hydroxyl group, and 5 to 30% by mass of structural unit (iv-a) derived from succinic acid mono(2-methacryloyloxyethyl). The total content of the structural units (i-a) to (iv-a) is 90% by mass or more, and it is a polymer block having a number average molecular weight of 4,000 to 10,000 and a molecular weight distribution of 1.1 to 1.6. [Requirement (3)] The polymer chain B' contains 10 to 60% by mass of structural unit (i-b) derived from at least one monomer selected from the group consisting of methyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate, and 40 to 90% by mass of structural unit (ii-b) derived from succinic acid mono(2-methacryloyloxyethyl). The total content of the structural units (i-b) and (ii-b) is 90% by mass or more, and it is a polymer block having a number average molecular weight of 2,000 to 8,000. [2] The alkali-developable polymer according to [1], wherein the epoxy group-containing (meth)acrylate is (3,4-epoxycyclohexyl)methyl methacrylate.

[0008] Furthermore, according to the present invention, an alkali-developable polymer composition shown below is provided. [3] The alkali-developable polymer according to [1] or [2], and an organic solvent, wherein the organic solvent contains at least one selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane in an amount of 50% by mass or more. An alkali-developable polymer composition. [Advantages of the Invention]

[0009] According to the present invention, high-precision patterning is possible, the curing characteristics and developability are good, and a cured product excellent in hardness and heat resistance can be formed. Even when a low-concentration alkali developer is used, an alkali-developable polymer that can be easily developed can be provided. Furthermore, according to the present invention, an alkali-developable polymer composition containing this alkali-developable polymer and suppressing the generation of outgas can be provided. [Embodiments for Carrying Out the Invention]

[0010] [Alkali-Developable Polymer] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. One embodiment of the alkali-developable polymer of the present invention is a reaction product obtained by reacting a specific A'B' block copolymer with an epoxy group-containing (meth) acrylate. The alkali-developable polymer of this embodiment has a number average molecular weight of 7,000 to 20,000, a molecular weight distribution (weight average molecular weight / number average molecular weight) of 1.2 to 1.8, an acid value of 40 to 100 mg / KOH, and an unsaturated group equivalent of 900 to 3,000 g / mol. It is an AB block copolymer containing a polymer chain A and a polymer chain B. Hereinafter, the details of the alkali-developable polymer of this embodiment will be described.

[0011] (A'B' Block Copolymer) The A'B' block copolymer is a precursor of the AB block copolymer, which is the alkali-developable polymer of this embodiment. The A'B' block copolymer is a block copolymer that satisfies the requirements (1) to (3) described in detail below.

[0012] [Requirement (1)] The A'B' block copolymer is a block copolymer containing polymer chain A' and polymer chain B', having a number average molecular weight of 6,000 to 18,000, a molecular weight distribution of 1.1 to 1.7, and an acid value of 70 to 130 mgKOH / g.

[0013] The number average molecular weight (Mn) of the A'B' block copolymer is 6,000 to 18,000, preferably 7,000 to 16,000. When the Mn of the A'B' block copolymer is less than 6,000, since the molecular weight is too small, the durability of the cured product of the AB block copolymer (alkali-developable polymer) obtained using this A'B' block copolymer is insufficient. On the other hand, when the Mn of the A'B' block copolymer exceeds 18,000, since the molecular weight is too large, it may take time to dissolve the alkali-developable polymer obtained using this A'B' block copolymer with an alkali developer (alkali developing solution). In addition, both the number average molecular weight (Mn) and the weight average molecular weight (Mw) in this specification are values in terms of polystyrene measured by gel permeation chromatography (GPC).

[0014] The molecular weight distribution (PDI = weight average molecular weight (Mw) / number average molecular weight (Mn)) of the A'B' block copolymer is 1.1 to 1.7, preferably 1.2 to 1.6. That is, the A'B' block copolymer is a polymer with relatively uniform molecular weights. Due to the uniformity of the molecular weights in this way, the properties of the molecular chains are uniform, and the developability of the AB block copolymer (alkali-developable polymer) obtained using this A'B' block copolymer can be improved. Also, since it is easily and uniformly soluble, the shape of the pixel is good, and it is difficult to be in a peeled state even after being dissolved.

[0015] The AB block copolymer needs to have a sufficient acid value for alkali development. Therefore, the A'B' block copolymer, which is the precursor of the AB block copolymer, also needs to have a sufficient acid value. That is, the acid value of the A'B' block copolymer is 70 to 130 mgKOH / g, preferably 80 to 120 mgKOH / g. If the acid value of the A'B' block copolymer is less than 70 mgKOH / g, the amount of carboxyl groups remaining after the reaction with the epoxy group-containing (meth)acrylate decreases, and the alkali developability may decrease. On the other hand, if the acid value of the A'B' block copolymer exceeds 130 mgKOH / g, even if the epoxy group-containing (meth)acrylate is reacted, too many carboxyl groups will remain. For this reason, while the developability may be improved, the water resistance of the cured product formed may decrease.

[0016] [Requirement (2)] The polymer chain A' (hereinafter also referred to as "A' chain") is a polymer block containing 15 to 55% by mass of the structural unit (i-a), 15 to 60% by mass of the structural unit (ii-a), 5 to 30% by mass of the structural unit (iii-a), and 5 to 30% by mass of the structural unit (iv-a) (however, the total of the structural units (i-a) to (iv-a) is 100% by mass). The structural unit (i-a) is a structural unit derived from at least one monomer selected from the group consisting of methyl methacrylate and benzyl methacrylate. The structural unit (ii-a) is a structural unit derived from at least one monomer selected from the group consisting of cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate. The structural unit (iii-a) is a structural unit derived from a methacrylate having a hydroxyl group. The structural unit (iv-a) is a structural unit derived from succinic acid mono(2-methacryloyloxyethyl). Also, in the A' chain, the total content of the structural units (i-a) to (iv-a) is 90% by mass or more. And the number average molecular weight of the A' chain is 4,000 to 10,000, and the molecular weight distribution is 1.1 to 1.6.

[0017] The A' chain contains a structural unit (iv-a) derived from succinic acid mono(2-methacryloyloxyethyl). By reacting the carboxy group in this structural unit (iv-a) with the epoxy group of the epoxy group-containing (meth)acrylate, the polymer chain A that constitutes the AB block copolymer is formed. The polymer chain A thus formed has an unsaturated bond and has little or only a small amount of carboxy group remaining, so it has poor water solubility. Therefore, by using the AB block copolymer containing this polymer chain A, a cured film having water resistance can be formed.

[0018] In the A' chain, the content of the structural unit (iv-a) is 5 to 30% by mass, preferably 10 to 25% by mass. When the content of the structural unit (iv-a) in the A' chain is less than 5% by mass, the amount of unsaturated groups introduced into the AB block copolymer decreases, resulting in insufficient curability. On the other hand, when the content of the structural unit (iv-a) in the A' chain exceeds 30% by mass, a large amount of carboxy groups remain even after reacting with the epoxy group-containing (meth)acrylate, and the water resistance of the formed cured film decreases.

[0019] Succinic acid mono(2-methacryloyloxyethyl) has a long ester residue. Further, when the carboxy group in the structural unit (iv-a) is reacted with the epoxy group-containing (meth)acrylate, the ester residue becomes even longer, so the glass transition temperature (Tg) of the polymer chain A becomes lower, and the formed cured film tends to be soft. Therefore, the A' chain contains a structural unit (ii-a) derived from at least one monomer selected from the group consisting of cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate. By including such a structural unit (ii-a) having a cycloalkyl group, the glass transition temperature (Tg) of the formed polymer chain A can be increased, and a hard cured film can be formed.

[0020] In the A' chain, the content of the structural unit (ii-a) is 15 to 60% by mass, preferably 20 to 55% by mass. When the content of the structural unit (ii-a) in the A' chain is less than 15% by mass, it becomes difficult to increase the hardness of the formed cured film. On the other hand, when the content of the structural unit (ii-a) in the A' chain exceeds 60% by mass, due to the strong hydrophobicity of the cycloalkyl group, it may be difficult to develop.

[0021] The A' chain further contains a structural unit (i-a) derived from at least one monomer selected from the group consisting of methyl methacrylate and benzyl methacrylate. The structural unit (i-a) is a water-insoluble or poorly water-soluble structural unit derived from a monomer with a small molecular weight or a monomer having an aromatic ring. By including such a structural unit (i-a), it is possible to obtain an AB block copolymer capable of forming a cured film with both developability and hardness. Note that if the number of carbon atoms is more than that of methyl methacrylate, the hydrophobicity becomes too high, making it difficult to develop with alkali and the formed cured film may become soft.

[0022] In the A' chain, the content of the structural unit (i-a) is 15 to 55% by mass, preferably 20 to 50% by mass. When the content of the structural unit (i-a) in the A' chain is less than 15% by mass, the developability may decrease. On the other hand, when the content of the structural unit (i-a) in the A' chain exceeds 55% by mass, the polymer chain A may become soft.

[0023] The A' chain further contains a structural unit (iii-a) derived from a methacrylate having a hydroxyl group. By including the structural unit (iii-a) having a hydrophilic hydroxyl group, the alkali developability of the AB block copolymer can be improved. Examples of the methacrylate having a hydroxyl group include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,3-dihydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, and 4-hydroxypropyl methacrylate. Among them, 2-hydroxyethyl methacrylate is preferred.

[0024] In the A’ chain, the content of the structural unit (iii-a) is 5 to 30% by mass, preferably 7.5 to 25% by mass. When the content of the structural unit (iii-a) in the A’ chain is less than 5% by mass, the alkali developability decreases. On the other hand, when the content of the structural unit (iii-a) in the A’ chain exceeds 30% by mass, the hydrophilicity becomes too high, and the water resistance of the formed cured film decreases. In addition, the cured film may swell with water or become sticky.

[0025] In the A’ chain, the total content of the structural units (i-a) to (iv-a) is 90% by mass or more, preferably 95% by mass or more. It should be noted that it is particularly preferable that the total content of the structural units (i-a) to (iv-a) in the A’ chain is 100% by mass, that is, the A’ chain is substantially composed only of the structural units (i-a) to (iv-a).

[0026] The A’ chain may further contain other structural units other than the structural units (i-a) to (iv-a). Examples of the monomers that form the other structural units include methacrylic acid and methacrylates. Examples of methacrylates include methacrylates having an alkyl group or an alkenyl group such as ethyl methacrylate, butyl methacrylate, t-butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate; hydroxyl group-containing methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 3-hydroxypropyl methacrylate; glycol ether-based methacrylates such as (poly)ethylene glycol monomethyl ether methacrylate, (poly)ethylene glycol monoethyl ether methacrylate, and (poly)propylene glycol monomethyl ether methacrylate; amino group-containing methacrylates such as dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and t-butylaminoethyl methacrylate; and the like.

[0027] The number average molecular weight (Mn) of the A' chain is 4,000 to 10,000, preferably 4,500 to 9,500. When the Mn of the A' chain is less than 4,000, the durability and water resistance of the cured film are insufficient. On the other hand, when the Mn of the A' chain exceeds 10,000, the developability decreases.

[0028] The molecular weight distribution (PDI) of the A' chain is 1.1 to 1.6, preferably 1.2 to 1.5. That is, the A' chain is a polymer block with relatively uniform molecular weights. Due to the uniformity of the molecular weights, the developability of the AB block copolymer (alkali-developable polymer) obtained using the A'B' block copolymer containing this A' chain can be improved. In addition, since it is easily dissolved uniformly, the shape of the pixel becomes good, and it is difficult to be in a state of peeling off even when dissolved.

[0029] [Requirement (3)] The polymer chain B' (hereinafter also referred to as the "B' chain") is a polymer block containing 10 to 60% by mass of the structural unit (i-b) and 40 to 90% by mass of the structural unit (ii-b) (however, the total of the structural units (i-b) and (ii-b) is 100% by mass). The structural unit (i-b) is a structural unit derived from at least one monomer selected from the group consisting of methyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate. The structural unit (ii-b) is a structural unit derived from succinic acid mono(2-methacryloyloxyethyl). Also, in the B' chain, the total content of the structural units (i-b) and (ii-b) is 90% by mass or more. And the number average molecular weight of the B' chain is 2,000 to 8,000.

[0030] The B’ chain contains a structural unit (ii-b) derived from mono(2-methacryloyloxyethyl) succinate. By introducing a large amount of this structural unit (ii-b), a large amount of carboxy groups can be introduced into the B’ chain. By introducing a predetermined amount of carboxy groups into the B’ chain, even when reacting an epoxy group-containing (meth)acrylate, a large amount of carboxy groups can remain. Then, since the remaining carboxy groups are neutralized by the alkali in the alkali developer and dissolved in water, the alkali developability can be improved. Further, carboxy groups exist at positions away from the main chain composed of polymethacrylate. As a result, it becomes easy to come into contact with the alkali in the alkali developer and easy to undergo a neutralization reaction, so that the dissolution time can be shortened and the alkali developability can be improved. Furthermore, since unsaturated bonds are densely introduced by reacting with an epoxy group-containing (meth)acrylate, the crosslink density can be increased, and a cured product having high hardness and excellent heat resistance can be formed.

[0031] In the B’ chain, the content of the structural unit (ii-b) is 40 to 90% by mass, preferably 45 to 85% by mass. When the content of the structural unit (ii-b) in the B’ chain is less than 40% by mass, the amount of carboxy groups remaining when reacting with an epoxy group-containing (meth)acrylate decreases, and the developability deteriorates. On the other hand, if the content of the structural unit (ii-b) in the B’ chain is to exceed 90% by mass, since the molecular weight of the monomer is large, the polymerization rate decreases and the monomer tends to remain.

[0032] The B’ chain further contains a structural unit (i-b) derived from at least one monomer selected from the group consisting of methyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate. By containing such a structural unit (i-b), an AB block copolymer capable of forming a cured film with both developability and hardness can be obtained, and the glass transition temperature (Tg) of the formed polymer chain B can be increased to form a hard cured film. Furthermore, by containing such a structural unit (i-b), it is possible to suppress the remaining of monosuccinic acid mono(2-methacryloyloxyethyl) which has a large molecular weight and is difficult to enhance polymerizability.

[0033] In the B’ chain, the content of the structural unit (i-b) is 10 to 60% by mass, preferably 5 to 50% by mass. When the content of the structural unit (i-b) in the B’ chain is less than 10% by mass, the copolymerizability of monosuccinic acid mono(2-methacryloyloxyethyl) is insufficient, and monosuccinic acid mono(2-methacryloyloxyethyl) may remain. On the other hand, when the content of the structural unit (i-b) in the B’ chain exceeds 60% by mass, the content of the structural unit (ii-b) relatively decreases, so the developability decreases.

[0034] The structural unit (i-b) is preferably a structural unit formed from at least one monomer of methyl methacrylate and benzyl methacrylate and at least one monomer of cyclohexyl methacrylate and dicyclopentenyl oxyethyl methacrylate. Thereby, the glass transition temperature (Tg) of the B’ chain, the hardness and stickiness of the formed cured film can be adjusted.

[0035] In the B’ chain, the total content of the structural units (i-b) and (ii-b) is 90% by mass or more, preferably 95% by mass or more. It is particularly preferable that the total content of the structural units (i-b) and (ii-b) in the B’ chain is 100% by mass, that is, the B’ chain is substantially composed only of the structural units (i-b) to (ii-b).

[0036] The B' chain may further contain other structural units other than the structural units (i-b) and (ii-b). Examples of the monomers forming the other structural units include methacrylic acid and the aforementioned methacrylates.

[0037] The number average molecular weight (Mn) of the B' chain is such that the number average molecular weight is from 2,000 to 8,000, preferably from 3,000 to 7,000. The Mn of the B' chain is the value obtained by subtracting the Mn of the A' chain from the Mn of the A'B' block copolymer. When the Mn of the B' chain is less than 2,000, the polymer block soluble in water becomes small, and the alkali developability decreases. On the other hand, when the Mn of the B' chain exceeds 8,000, the water resistance of the cured film decreases while containing the water-insoluble or hardly soluble A' chain.

[0038] (Method for producing A'B' block copolymer) Since the A'B' block copolymer has a special structure, it is difficult to produce by ordinary radical polymerization. Therefore, the A'B' block copolymer is preferably produced by a living polymerization method such as a living anionic polymerization method, a living cationic polymerization method, and a living radical polymerization method. Among them, from the viewpoints of conditions, materials, apparatuses, etc., it is preferably produced by a living radical polymerization method. Further, the RTCP method and the RCMP method using an organic compound as a catalyst and an organic iodide as a polymerization initiator compound are preferred. These methods use relatively safe commercially available compounds, do not use heavy metals or special compounds, and are advantageous in terms of cost and purification. Further, by making the growing end a tertiary iodine, an accurate block structure can be easily formed with general equipment.

[0039] Either the A' chain or the B' chain polymer block may be polymerized first. It is preferable to polymerize the B' chain after polymerizing the A' chain. If the B chain is polymerized first, when succinic acid mono(2-methacryloyloxyethyl) remains in the polymerization system, a large amount of the structural unit (iv-a) may be introduced into the subsequently polymerized A' chain.

[0040] The A'B' block copolymer is preferably produced by solution polymerization. As the organic solvent used in solution polymerization, the organic solvent used in the alkali-developable polymer composition described below can also be used. Further, after polymerization in an organic solvent, the solid obtained by adding a poor solvent to precipitate the polymer may be dissolved in an organic solvent.

[0041] (AB block copolymer) The alkali-developable polymer of the present embodiment is an AB block copolymer containing a polymer chain A (hereinafter, also simply referred to as "A chain") and a polymer chain B (hereinafter, also simply referred to as "B chain"), which is a reaction product obtained by reacting the above-described A'B' block copolymer with an epoxy group-containing (meth)acrylate. The alkali-developable polymer (AB block copolymer) of the present embodiment is such that all of its constituent monomers are methacrylate-based monomers such as methacrylic acid esters. That is, the monomers forming the constituent units in the alkali-developable polymer of the present embodiment are preferably substantially composed of only methacrylate-based monomers such as methacrylic acid esters.

[0042] Examples of the epoxy group-containing (meth)acrylate include glycidyl (meth)acrylate and (3,4-epoxycyclohexyl)methyl (meth)acrylate. Among them, (3,4-epoxycyclohexyl)methyl methacrylate having a cycloalkyl ring is preferable from the viewpoints of easy availability and improvement of the hardness of the polymer.

[0043] The number average molecular weight (Mn) of the AB block copolymer is 7,000 to 20,000, preferably 8,000 to 18,000. When the Mn of the AB block copolymer is less than 7,000, the molecular weight is too small, so the durability of the cured film is insufficient. On the other hand, when the Mn of the AB block copolymer exceeds 20,000, the molecular weight is too large, so the alkali developability decreases.

[0044] The molecular weight distribution (PDI) of the AB block copolymer is 1.2 to 1.8, preferably 1.2 to 1.7. That is, the AB block copolymer is a polymer with relatively uniform molecular weights. Due to such uniformity of molecular weights, the properties of the molecular chains are uniform, and the developability can be improved. Also, since it is easily and uniformly soluble, the shape of the pixel is improved, and it is difficult to become a state of peeling even when dissolved.

[0045] Since the AB block copolymer is a reaction product obtained by reacting an A'B' block copolymer with an epoxy group-containing (meth)acrylate, the acid value of the AB block copolymer is smaller than the acid value of the A'B' block copolymer. That is, the acid value of the AB block copolymer is 40 to 100 mg / KOH, preferably 45 to 90 mg KOH / g. When the acid value of the AB block copolymer is less than 40 mg KOH / g, it cannot be developed or the development rate (dissolution rate) becomes slow. On the other hand, when the acid value of the AB block copolymer exceeds 100 mg KOH / g, the amount of remaining carboxy groups is too large, and the water resistance of the cured film decreases. The acid value of the AB block copolymer can be controlled by adjusting the acid value of the A'B' block copolymer and the number of moles of the epoxy group-containing (meth)acrylate reacted with the A'B' block copolymer.

[0046] The unsaturated group equivalent of the AB block copolymer is 900 to 3,000 g / mol, preferably 1,000 to 2,800 g / mol. When the unsaturated group equivalent of the AB block copolymer is less than 900 g / mol, it becomes difficult to increase the crosslinking density of the formed cured film, and the strength of the cured film is insufficient. On the other hand, when the unsaturated group equivalent of the AB block copolymer exceeds 3,000 g / mol, the alkali developability decreases.

[0047] The A’B’ block copolymer and the epoxy group-containing (meth)acrylate can be reacted according to a conventionally known method. For example, the reaction can be carried out under temperature conditions of 120 °C or lower in the presence of a catalyst such as a phosphorus compound like triphenylphosphine or a quaternary ammonium salt like tetrabutylammonium bromide. In addition, a polymerization inhibitor such as hydroquinone may be added or air may be fed in order to prevent the unsaturated bonds of the epoxy group-containing (meth)acrylate from reacting or polymerizing. The end point of the reaction can be confirmed by measuring IR with an infrared spectrophotometer and confirming the disappearance of the absorption derived from the epoxy group; measuring the epoxy equivalent and confirming that the epoxy equivalent becomes zero; measuring the acid value and confirming that it reaches a predetermined value; and other methods.

[0048] <Alkaline developable polymer composition> One embodiment of the alkaline developable polymer composition of the present invention contains the aforementioned alkaline developable polymer and an organic solvent. And the organic solvent is at least one selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane. Hereinafter, the details of the alkaline developable polymer composition (hereinafter, also referred to as "resist ink composition") of this embodiment will be described.

[0049] Generally, when using an alkaline developable resist composition containing a high-boiling organic solvent, the organic solvent remains in the pre-bake and post-bake processes, and the remaining organic solvent becomes outgas and is likely to contaminate mechanical devices and the like. In contrast, in the alkaline developable polymer composition (resist ink composition) of this embodiment, at least one kind of organic solvent having a relatively low boiling point, selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane, which can dissolve the alkaline developable polymer, is used. Under normal pressure conditions, the boiling point of propyl acetate is 102 °C, the boiling point of butyl acetate is 126 °C, and the boiling point of methoxycyclopentane is 106 °C. These organic solvents also have a high vapor pressure, are volatile, and are less likely to remain even after baking.

[0050] In the organic solvent contained in the alkali-developable polymer composition, the content of at least one selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane is 50% by mass or more, preferably 80% by mass or more. In the organic solvent, it is particularly preferable that the content of at least one selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane is 100% by mass, that is, the organic solvent is substantially composed of only at least one selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane.

[0051] The organic solvent in the alkali-developable polymer composition may further contain other organic solvents other than the above-mentioned organic solvents. Examples of other organic solvents include propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, N-methylpyrrolidone, and γ-butyrolactone.

[0052] The content of the alkali-developable polymer (AB block copolymer) in the alkali-developable polymer composition and the viscosity of the alkali-developable polymer composition are not particularly limited and may be appropriately set according to the application and the like. The alkali-developable polymer composition can be produced, for example, by reacting an A'B' block copolymer formed by polymerization in an organic solvent with an epoxy group-containing (meth)acrylate and then adding and diluting the organic solvent so as to obtain the desired content of the AB block copolymer.

[0053] Additives can be contained in the alkali-developable polymer composition. Examples of additives include photopolymerizable monomers, photopolymerizable oligomers, ultraviolet absorbers, light stabilizers, photopolymerization initiators, photosensitizers, acid-base generators, antioxidants, leveling agents, defoaming agents, thickeners, and colorants such as pigments.

Examples

[0054] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are based on mass unless otherwise specified.

[0055] <Production of alkali-developable polymer> (Synthesis Example 1) 239.1 parts of propylene glycol monomethyl ether acetate (PGMAc), 4.0 parts of iodine, 14.8 parts of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70) (trade name "V-70", manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), 0.7 part of difluoromethane (DPM), 58.2 parts of benzyl methacrylate (BzMA), 58.2 parts of cyclohexyl methacrylate (CHMA), 32.5 parts of 2-hydroxyethyl methacrylate (HEMA), and 27.2 parts of succinic acid mono(2-methacryloyloxyethyl) (SA) (trade name "SA", manufactured by Shin-Nakamura Chemical Co., Ltd., Mw 230.21) were placed in a reaction vessel. While flowing nitrogen, the mixture was heated to 45°C and stirred, and polymerized for 4 hours to form an A' chain (polymer). A part was sampled, and the solid content measured using a moisture meter was 39.7%, and the polymerization conversion rate calculated from the solid content was 88.2%. The molecular weight of the polymer was measured by gel permeation chromatography (GPC) using a differential refractive index detector with tetrahydrofuran as the developing solvent. As a result, the number average molecular weight (Mn) of the polymer in terms of polystyrene was 4,700, the molecular weight distribution (PDI = weight average molecular weight (Mw) / number average molecular weight (Mn)) was 1.28, and the peak top molecular weight (PT) was 6,200. Also, the theoretical acid value of the A' chain was 37.5 mgKOH / g. The theoretical acid value was calculated as follows. · Amount of SA in 1 g of A' chain (g) = 27.2 / (58.2 + 58.2 + 32.5 + 27.2) = 0.154 · Acid value (mgKOH / g) =(0.154 / 230.21)×56.11×1,000 = 37.5

[0056] After adding 10.6 parts of V-70, a monomer solution containing 74.5 parts of BzMA, 138.1 parts of SA, and 272.8 parts of PGMAc was further added. It was heated to 45 °C, stirred, and polymerized for 4 hours to form the B' chain and obtain a polymer. A part was sampled to measure the solid content, and it was confirmed that the target product was obtained almost quantitatively. The Mn of the obtained polymer was 10,100, the PDI was 1.55, and the PT was 15,200. Since Mn was larger than that of the A' chain, the obtained polymer was considered to be an A'B' block copolymer. The Mn of the B' chain calculated by subtracting the Mn of the A' chain from the Mn of the A'B' block copolymer was 5,400.

[0057] 0.8 part of 4-methoxyphenol (MEHQ), 3.9 parts of tetrabutylammonium bromide (TBAB), and 58.9 parts of (3,4-epoxycyclohexyl)methyl methacrylate (M100) (trade name "Cyclomer M100", manufactured by Daicel Corporation, Mw 196.2) were added. It was heated to 90 °C and reacted for 3 hours to obtain a solution containing an AB block copolymer (solution of alkali-developable polymer EP-1). A part was sampled, and IR was measured using an infrared spectrophotometer. By confirming the disappearance of the absorption peak derived from the epoxy group, the completion of the reaction was confirmed. The solid content was 47.5%. After dilution with toluene and ethanol, the acid value (measured acid value) measured by acid-base titration using a phenolphthalein solution as an indicator and 0.1% ethanolic potassium hydroxide solution was 53.5 mgKOH / g.

[0058] (Synthesis Examples 2 to 5) Solutions of alkali-developable polymers EP-2 to 5 were obtained in the same manner as in Synthesis Example 1 described above, except that various materials of the types and amounts (unit: part) shown in Tables 1-1 and 1-2 were used. The physical properties, etc. of the obtained alkali-developable polymers are shown in Tables 1-1 and 1-2. The meanings of the abbreviations in Tables 1-1 and 1-2 are shown below. · MMA: Methyl methacrylate · TMCHMA: 3,3,5-Trimethylcyclohexyl methacrylate ·TBCHMA: 4-tert-Butylcyclohexyl methacrylate ·FA513M: Dicyclopentanyl methacrylate (trade name "Funcrile FA513M", manufactured by Showa Denko Materials Co., Ltd.) ·FA512M: Dicyclopentenyl oxyethyl methacrylate (trade name "Funcrile FA512M", manufactured by Showa Denko Materials Co., Ltd.) ·GMA: Glycidyl methacrylate ·SA·M100: Adduct of SA and M100 (Mw 426.41) ·SA·GMA: Adduct of SA and GMA (Mw 372.36)

[0059] Note that the "unsaturated group equivalent weight" in Tables 1-1 and 1-2 was calculated as follows. For example, in the case of Synthesis Example 1, since 0.286 g of SA·M100 is contained in 1 g of the polymer, the amount (mol) of SA·M100 in 1 g of the polymer is "0.286 / 426.41 = 0.0006707 mol". Therefore, the unsaturated group equivalent weight of the alkali-developable polymer EP-1 obtained in Synthesis Example 1 can be calculated as "1 / 0.0006707 = 1,491 g / mol".

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[0061] TIFF0007706484000002.tif255154

[0062] (Synthesis Example 6) 119.5 parts of PGMAc, 119.6 parts of propyl acetate, 4.0 parts of iodine, 14.8 parts of V-70, 0.7 part of DPM, 33.2 parts of BzMA, 99.5 parts of CHMA, 16.2 parts of HEMA, and 27.2 parts of SA were placed in a reaction vessel. While flowing nitrogen, the mixture was heated to 45 °C and stirred, and polymerized for 4 hours to form an A' chain (polymer). The solid content was 41.5%, and the polymerization conversion rate calculated from the solid content was 92.2%. The Mn measured by GPC was 5,100, the PDI was 1.36, and the PT was 6,900. Also, the theoretical acid value of the A' chain was 37.5 mgKOH / g.

[0063] After adding 7.1 parts of V-70, a monomer solution containing 12.4 parts of BzMA, 37.2 parts of CHMA, 92.1 parts of SA, 90.9 parts of PGMAc, and 91.0 parts of propyl acetate was further added. It was heated to 45 °C, stirred, and polymerized for 4 hours to form the B’ chain and obtain a polymer. A part was sampled to measure the solid content, and it was confirmed that the target product was obtained almost quantitatively. The Mn of the obtained polymer was 8,000, the PDI was 1.45, and the PT was 11,700. Since the Mn was larger than that of the A’ chain, the obtained polymer was considered to be an A’B’ block copolymer. The Mn of the B’ chain calculated by subtracting the Mn of the A’ chain from the Mn of the A’B’ block copolymer was 2,900.

[0064] 0.5 part of MEHQ, 2.6 parts of TBAB, and 39.3 parts of M100 were added. It was heated to 90 °C and reacted for 3 hours to obtain a solution containing an AB block copolymer (solution of alkali-developable polymer EP-6). A part was sampled, and IR was measured using an infrared spectrophotometer. The completion of the reaction was confirmed by confirming the disappearance of the absorption peak derived from the epoxy group. The solid content was 47.8%. The actually measured acid value was 52.2 mgKOH / g.

[0065] (Synthesis Examples 7 and 8) Solutions of alkali-developable polymers EP-7 and 8 were obtained in the same manner as in Synthesis Example 6 described above, except that various materials of the types and amounts (unit: part) shown in Table 2 were used. The physical properties, etc. of the obtained alkali-developable polymers are shown in Table 2.

[0066] TIFF0007706484000003.tif255164

[0067] (Comparative Synthesis Example 1) 239.0 parts of PGMAc, 4.0 parts of iodine, 14.8 parts of V-70, 0.7 part of DPM, 58.2 parts of BzMA, 58.2 parts of CHMA, 32.5 parts of HEMA, and 27.2 parts of methacrylic acid (MAA) were placed in a reaction vessel. While flowing nitrogen, it was heated to 42 °C, stirred, and polymerized for 4.5 hours to form an A' chain (polymer). The solid content was 38.4%, and the polymerization conversion rate calculated from the solid content was 85.3%. Mn measured by GPC was 5,000, PDI was 1.26, and PT was 6,400. Also, the theoretical acid value of the A' chain was 100.4 mgKOH / g.

[0068] After adding 10.5 parts of V-70, a monomer solution containing 141.0 parts of BzMA, 68.9 parts of MAA, and 731.7 parts of PGMAc was further added. It was heated to 42 °C, stirred, and polymerized for 4 hours to form a B' chain and obtain a polymer. A part was sampled to measure the solid content, and it was confirmed that the target product was obtained almost quantitatively. The Mn of the obtained polymer was 9,400, PDI was 1.49, and PT was 14,200. Since Mn was larger than that of the A' chain, the obtained polymer was considered to be an A'B' block copolymer. The Mn of the B' chain calculated by subtracting the Mn of the A' chain from the Mn of the A'B' block copolymer was 4,400.

[0069] 0.3 part of MEHQ, 5.2 parts of TBAB, and 78.5 parts of M100 were added. It was heated to 90 °C and reacted for 3 hours to obtain a solution containing an AB block copolymer (a solution of an alkali-developable polymer HEP-1). A part was sampled and IR was measured using an infrared spectrophotometer, and the completion of the reaction was confirmed by confirming the disappearance of the absorption peak derived from the epoxy group. The solid content was 47.3%. The measured acid value was 87.2 mgKOH / g.

[0070] (Comparative Synthesis Examples 2 to 4) A solution of alkali-developable polymers HEP-2 to 4 was obtained in the same manner as in Comparative Synthesis Example 1 described above, except that various materials of the types and amounts (unit: part) shown in Tables 3-1 and 3-2 were used. The physical properties and the like of the obtained alkali-developable polymers are shown in Tables 3-1 and 3-2. In Tables 3-1 and 3-2, "MAA·M100" means an adduct of MAA and M100 (Mw 282.29).

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[0073] (Comparative Synthesis Example 5) 583.1 parts of PGMAc were placed in a reaction vessel and heated to 70°C. A monomer solution containing 12.0 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) (V-65) (trade name "V-65", manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), 132.7 parts of BzMA, 58.2 parts of CHMA, 32.5 parts of HEMA, and 165.3 parts of SA was added dropwise over 1.5 hours. After the dropwise addition, polymerization was carried out at 70°C for 6 hours to form a polymer, and a polymer solution was obtained. The solid content of the obtained polymer solution was 41.5%. The Mn of the polymer was 16,700, the PT was 36,500, and the PDI was 2.15.

[0074] 0.8 part of MEHQ, 3.9 parts of TBAB, and 58.9 parts of M100 were added. The mixture was heated to 90°C and reacted for 3 hours to obtain a solution containing a random copolymer (a solution of alkali-developable polymer HEP-5). A part was sampled and IR was measured using an infrared spectrophotometer, and the completion of the reaction was confirmed by confirming the disappearance of the absorption peak derived from the epoxy group. The solid content was 43.8%. The actually measured acid value was 54.1 mgKOH / g.

[0075] ><Production of Resist Ink Composition (Alkali-Developable Polymer Composition)> (Example 1) 26.3 parts of a solution of an alkali-developable polymer EP-1, 52.7 parts of PGMAc, 20.0 parts of dipentaerythritol hexaacrylate (DPHA) (trade name "SR899NS", manufactured by Arkema), and 1.0 part of 1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazole-3-yl]ethanone O-acetoxyoxime (OXE-02) (trade name "Irgacure OXE-02", manufactured by BASF) were blended and thoroughly mixed using a mixer to obtain a resist ink composition-1.

[0076] (Examples 2 to 8, Comparative Examples 1 to 5) Resist ink compositions-2 to 13 were obtained in the same manner as in Example 1 described above, except that the formulations shown in Table 4 were used.

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[0078] <Manufacture of Resin-Coated Glass Substrate> (Application Example 1) The resist ink composition-1 was spin-coated onto a thoroughly cleaned glass substrate so that the final film thickness was 2.0 μm. After pre-baking at 90°C for 2 minutes, a photomask for forming a 1 cm × 3 cm pattern was used, and exposure was performed using an ultra-high pressure mercury lamp with a light quantity of 100 mJ / cm 2 Then, post-baking was performed at 230°C for 30 minutes to obtain a resin-coated glass substrate-1.

[0079] (Application Examples 2 to 8, Comparative Application Examples 1 to 5) Resin-coated glass substrates-2 to 13 were manufactured in the same manner as in Application Example 1 described above, except that the resist ink compositions shown in Table 5 were used respectively.

[0080] <Evaluation> The unexposed portions of the manufactured resin-coated glass substrates were alkali-developed using a 5% aqueous solution of tetramethylammonium hydroxide. Then, the time until the unexposed portions were completely dissolved (dissolution time (seconds)) was measured, and the development behavior, the presence or absence of dissolution residues, and the presence or absence of stickiness of the coating film were confirmed. The results are shown in Table 5.

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[0082] When the edges of the exposed portions remaining undissolved in the resin-coated glass substrates - 1 to 8 obtained in Application Examples 1 to 8 were observed with a microscope, it was confirmed that all of them were sharp. From this, it was found that any of the resist ink compositions - 1 to 8 was excellent in alkali developability.

[0083] In addition, it was found that the resin-coated glass substrates - 1 to 8 obtained in Application Examples 1 to 8 all had excellent light transmittance. Note that the resin-coated glass substrates - 6 to 8 obtained in Application Examples 6 to 8 were produced using an alkali-developable polymer polymerized in combination with a specific organic solvent (propyl acetate, butyl acetate, methoxycyclopentane) having a lower boiling point than PGMAc. Furthermore, since the resist ink compositions used when producing these resin-coated glass substrates - 6 to 8 contained the above specific organic solvent, it was found that almost no outgas was generated in the resin-coated glass substrates - 6 to 8.

Industrial Applicability

[0084] The alkali-developable polymer of the present invention and the composition (resist ink composition) using the same are useful as a patterning material used, for example, in the production of printed wiring boards, semiconductor packages, insulating films, printing plates, spacers for liquid crystal cells, color filters, and black matrices.

Claims

1. It is a reaction product obtained by reacting an epoxy group-containing (meth)acrylate with an A'B' block copolymer satisfying the following requirements (1) to (3). An alkali-developable polymer which is an AB block copolymer containing polymer chain A and polymer chain B, having a number average molecular weight of 7,000 to 20,000, a molecular weight distribution (weight average molecular weight / number average molecular weight) of 1.2 to 1.8, an acid value of 40 to 100 mg / KOH, and an unsaturated group equivalent of 900 to 3,000 g / mol. [Requirement (1)] It is a block copolymer containing polymer chain A' and polymer chain B', having a number average molecular weight of 6,000 to 18,000, a molecular weight distribution of 1.1 to 1.7, and an acid value of 70 to 130 mg KOH / g. [Requirement (2)] The polymer chain A' is 15 to 55% by mass of a structural unit (i-a) derived from at least one monomer selected from the group consisting of methyl methacrylate and benzyl methacrylate, 15 to 60% by mass of a structural unit (ii-a) derived from at least one monomer selected from the group consisting of cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate, 5 to 30% by mass of a structural unit (iii-a) derived from a methacrylate having a hydroxyl group, and 5 to 30% by mass of a structural unit (iv-a) derived from succinic acid mono(2-methacryloyloxyethyl), and The total content of the structural units (i-a) to (iv-a) is 90% by mass or more, It is a polymer block having a number average molecular weight of 4,000 to 10,000 and a molecular weight distribution of 1.1 to 1.

6. [Requirement (3)] The polymer chain B' is 10 to 60% by mass of a structural unit (i-b) derived from at least one monomer selected from the group consisting of methyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, and dicyclopentenyl oxyethyl methacrylate, and 40 to 90% by mass of a structural unit (ii-b) derived from succinic acid mono(2-methacryloyloxyethyl), and The total content of the structural units (i-b) and (ii-b) is 90% by mass or more, It is a polymer block having a number average molecular weight of 2,000 to 8,000.

2. The alkali-developable polymer according to claim 1, wherein the epoxy group-containing (meth)acrylate is (3,4-epoxycyclohexyl)methyl methacrylate.

3. An alkali-developable polymer composition containing the alkali-developable polymer according to claim 1 or 2 and an organic solvent, wherein the organic solvent contains at least one selected from the group consisting of propyl acetate, butyl acetate, and methoxycyclopentane in an amount of 50% by mass or more.

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