Acetalized sugars, photosensitive compositions, and positive-type resist compositions

Abstract

This can provide novel sugars containing an acetal group. [Solution] Acetalized sugars are formed in which at least a portion of the hydroxyl groups of the sugars are modified into acetal groups.

Description

[Technical Field]

[0001] This invention relates to acetalized sugars and their uses. [Background technology]

[0002] Patent Document 1 describes a resist material characterized by using a polymer compound having a weight-average molecular weight in the range of 1,000 to 500,000, which contains repeating units a having acid-unstable groups, as the base resin.

[0003] Patent Document 2 describes a positive-type resist composition containing a sulfonium compound and a polymer as a base polymer that contains predetermined repeating units, decomposes upon the action of an acid, and whose solubility in an alkaline developer increases.

[0004] Patent Document 3 describes a water-soluble sugar in which at least a portion of the hydroxyl groups of the sugar are modified into polymerizable groups. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-102837 [Patent Document 2] Japanese Patent Publication No. 2018-109764 [Patent Document 3] Japanese Patent Publication No. 2021-161199 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Patent documents 1 to 3 do not disclose any materials having acetal groups produced using sugars as the main material.

[0007] The inventors have discovered that protecting the hydroxyl groups of sugars with acetal groups not only imparts high resistance to swelling in water to the sugars, but also restores the high water solubility inherent in the sugars by removing the acetal groups, making it extremely useful as a novel material.

[0008] One aspect of the present invention aims to provide novel sugars comprising an acetal group, and related technologies. [Means for solving the problem]

[0009] To solve the above problems, an acetalized sugar according to one aspect of the present invention is obtained by modifying at least a portion of the hydroxyl groups present in the sugar into acetal groups.

[0010] Furthermore, a photosensitive composition according to one aspect of the present invention contains acetalized sugars according to one aspect of the present invention and a photoacid generator. [Effects of the Invention]

[0011] According to one aspect of the present invention, it is possible to provide novel sugars comprising an acetal group, and related technologies. [Modes for carrying out the invention]

[0012] <Terminology> Where used herein, a numerical range indicated by "~" represents a range that includes the numbers before and after the "~" as the minimum and maximum values, respectively.

[0013] As used herein, when simply referred to as "sugars," unless otherwise specified, it means "sugars" that are raw materials for "acetalized sugars" according to one aspect of the present invention. Such "sugars" encompass carbohydrates in the field of food science.

[0014] Also, as used herein, the term "acetalated saccharide" means a "saccharide" in which at least a part of the hydroxyl groups of the saccharide are modified into acetal groups, thereby protecting the hydroxyl groups.

[0015] Also, as used herein, the term "photosensitivity" means that when an actinic ray selected from the group consisting of visible light, infrared rays, ultraviolet rays, and electron beams irradiates a composition, the compound contained in the composition generates radicals or protons (H+) by absorbing the actinic ray, and it is a property exhibited by the composition due to these radicals or protons (H+), which means the elimination of the acetal group of the acetalated saccharide and the change in the properties of the composition containing the acetalated saccharide associated therewith.

[0016] The inventors have found that by acetalating the hydroxyl groups of saccharides, the water solubility of saccharides that are originally water-soluble can be extremely reduced. Acetalated saccharides can form a coating film that is difficult to swell with water because the hydroxyl groups of the saccharides are protected by acetal groups. Also, in acetalated saccharides, hydroxyl groups are formed by deprotection of the acetal groups by an acid, and the high solubility in water that the saccharides originally have can be restored. Acetalated saccharides have the property that a coating film that is difficult to swell with water (aqueous solvent) can be obtained and the property that the high water solubility that the saccharides originally have can be restored by an acid. Therefore, acetalated saccharides are useful, for example, as a base resin contained in a photosensitive composition. Also, one advantage of the photosensitive composition is that it can be developed with water, not with an aqueous alkali solution.

[0017] <Acetalated Saccharide> For example, the acetalated saccharide according to one aspect of the present invention is a saccharide in which at least a part of the plurality of hydroxyl groups (-OH) of the saccharide is modified into an acetal group represented by the following formula (1).

[0018]

Chemical Formula

[0019] In formula (1), C* is a carbon atom included in the sugar chain, selected from the carbon atoms at positions 1, 2, 3, 4, 5, and 6 of the sugar chain, as well as carbon atoms at other positions.

[0020] In formula (1), R 1 and R 2 Each is independently selected from a hydrogen atom and an alkylene group having 1 to 10 carbon atoms, R 1 and R 2 One of them may be a hydrogen atom, and the other may be a methyl group.

[0021] In formula (1), R 3 R is selected from alkyl groups, and the number of carbon atoms constituting the alkyl group is represented by an integer from 1 to 30, more specifically, 3 More specifically, the alkyl groups represented by can include, for example, ethyl groups, propyl groups, n-butyl groups, i-butyl groups, hexyl groups, cyclohexyl groups, and 2-ethylhexyl groups.

[0022] In acetalized sugars, the denaturation rate is defined as the percentage of hydroxyl groups converted to acetal groups, with the total amount of hydroxyl groups in the raw material sugars being set at 100 mol%. Furthermore, from the perspective of protecting the hydroxyl groups with acetal groups, the denaturation rate from hydroxyl groups to acetal groups also represents the protection rate of the hydroxyl groups in the sugars. In one aspect of the present invention, the acetalized sugar has a denaturation rate of hydroxyl groups to acetal groups of preferably 40 mol% or more, and more preferably 50 mol% or more. This allows for a lower water solubility inherent in the sugars, thereby imparting water-resistant swelling to the acetalized sugar coating. Also, in one aspect of the present invention, the denaturation rate of hydroxyl groups to acetal groups is not limited, but may be 100 mol%. The denaturation rate of acetalized sugars can be appropriately designed depending on the application. The denaturation rate of acetalized sugars is: 13 This can be determined by 13C-NMR (nuclear magnetic resonance spectroscopy).

[0023] The weight-average molecular weight (Mw) of acetalized sugars is preferably 200 or more, more preferably 500 or more, and even more preferably 1500 or more. A weight-average molecular weight (Mw) of acetalized sugars of, for example, 200 or more enhances the water-resistant swelling of the coating film formed by the acetalized sugars. Furthermore, the weight-average molecular weight (Mw) of acetalized sugars is preferably 400,000 or less, and more preferably 200,000 or less. A weight-average molecular weight (Mw) of acetalized sugars of 400,000 or less enhances the exposure sensitivity and resolution of the acetalized sugars when used, for example, as a base resin for a resist. The weight-average molecular weight (Mw) of acetalized sugars is measured by gel permeation chromatography (GPC) as a value equivalent to standard polystyrene.

[0024] [Glycan linkage pattern] Acetalized sugars may have at least one of the following bonds in at least a portion of their sugar chain: a 1,2-bond, a 1,3-bond, a 1,4-bond, and a 1,6-bond. For example, a "1,3-bond" means at least one of the following: an α-glycosidic bond and a β-glycosidic bond, formed by a hydroxyl group bonded to the carbon atom at position 1 of the sugar and a hydroxyl group bonded to the carbon atom at position 3 of a sugar in a different molecule. Similarly, a 1,2-bond, a 1,4-bond, and a 1,6-bond each mean at least one of the following: an α-glycosidic bond and a β-glycosidic bond. In other words, unless otherwise specified herein, when simply referred to as a "1,2-bond," "1,3-bond," "1,4-bond," and "1,6-bond," these bonds have the meaning of either an α-glycosidic bond or a β-glycosidic bond, or both.

[0025] It is preferable that acetalized sugars have at least one of the following in at least a portion of their sugar chain: α1,4-linkage, α1,6-linkage, α1,2-linkage, α1,3-linkage, and β1,4-linkage, and it is more preferable that they have α1,4-linkage, α1,6-linkage, α1,2-linkage, and α1,3-linkage.

[0026] The presence of 1,4- and 1,6-links in acetalized sugars increases the branching structure of the acetalized sugars. This improves the coatability of compositions containing acetalized sugars during coating and enhances adhesion after coating. In acetalized sugars, with the total amount of glycosidic bonds in the sugar chain being 100 mol%, the total amount of 1,4- and 1,6-links is preferably 30 mol% or more, and more preferably 50 mol% or more. This improves the polymerizability of the acetalized sugars. Furthermore, with the total amount of glycosidic bonds in the sugar chain of acetalized sugars being 100 mol%, the total amount of 1,4- and 1,6-links is preferably 90 mol% or less, and more preferably 80 mol% or less. This improves the water solubility of the sugars after the acetal group is removed from the acetalized sugars.

[0027] In acetalized sugars, with the total amount of glycosidic bonds in the sugar chain being 100 mol%, the amount of 1,3-bonds is preferably 5 mol% or more, and more preferably 15 mol% or more. This can increase the strength of the acetalized sugars. Furthermore, with the total amount of glycosidic bonds in the acetalized sugar chain being 100 mol%, the amount of 1,3-bonds is preferably 70 mol% or less, and more preferably 50 mol% or less. This can maintain the water solubility of the sugar after the acetal group is removed from the acetalized sugar chain. Note that with the total amount of glycosidic bonds in the acetalized sugar chain being 100 mol%, the amount of 1,3-bonds is 13 This can be determined by 13C-NMR (nuclear magnetic resonance spectroscopy).

[0028] Furthermore, if acetalized sugars have one or both of 1,4-links and 1,6-links in at least a portion of their sugar chain, the 1,4-links and 1,6-links may form the main chain structure of the sugar chain, and the 1,3-links may form the side chain structure of the sugar chain.

[0029] In the case of acetalated saccharides, the sugar chain bonding mode is typically the same as that of the saccharide serving as the raw material and forming the backbone of the acetalated saccharide. However, depending on the steps such as hydrolysis and dehydration condensation that the production method may include, the acetalated saccharide may have a sugar chain bonding mode different from that of the raw material saccharide.

[0030] Unlike conventional functional materials such as resist materials that use petroleum-derived raw materials, the acetalated saccharide according to one aspect of the present invention can be produced using saccharides, which are natural-derived polymers, as raw materials. Therefore, one of the advantages is that acetalated saccharides can be provided as functional materials with a high biomass content. The biomass content may be measured by accelerator mass spectrometry (AMS) through radiocarbon concentration measurement ( 14 [[ID=_{6}]]C biomass content measurement).

[0031] Also, by adding a photosensitizer, the acetalated saccharide according to one aspect of the present invention can regain its high solubility in water that saccharides originally have. Therefore, the acetalated saccharide according to one aspect of the present invention can be, for example, an acetalated saccharide for a resist agent.

[0032] 〔Method for producing acetalated saccharide〕 The acetalated saccharide according to one aspect of the present invention can be produced, for example, by reacting a saccharide with an olefin ether compound such as a vinyl ether compound in an organic solvent in the presence of a catalyst, thereby modifying at least the hydroxyl groups of the saccharide into acetal groups.

[0033] 〔Saccharides〕 The sugars used as raw materials for acetalized sugars are those that form the backbone of the acetalized sugar. Typically, the raw material sugars are one or more selected from the group consisting of disaccharides, trisaccharides, tetrasaccharides, oligosaccharides, polysaccharides, carbohydrates, and dietary fiber. The raw material sugars for acetalized sugars may be one type or a combination of two or more types. The raw material sugars may be artificially synthesized sugars or natural sugars. Furthermore, if the raw material sugars are poorly water-soluble, sugars obtained by hydrolysis of such sugars may be used as raw materials. Furthermore, if the raw material sugars are poorly water-soluble, sugars to which hydrophilic groups such as hydroxyalkylene groups have been introduced to improve water solubility may be used as raw materials. The raw material sugars are not limited, but may be sugars with a solubility of 5% by weight or more in water at 20°C.

[0034] Examples of disaccharides include sucrose, lactose, maltose, trehalose, turanose, and cellobiose. Examples of trisaccharides include raffinose, melegitose, and maltotriose. Examples of tetrasaccharides include acarbose and stachyose. Examples of oligosaccharides include fructooligosaccharides, galactooligosaccharides, mannanoligosaccharides, and lactulose-fructose oligosaccharides. Examples of polysaccharides include glycogen, starch, pullulan, dextrin, cyclodextrin, dextrose, cellulose, glucan, fructan, and chitin; as well as polysaccharides in which some of the hydroxyl groups of these polysaccharides are modified by hydrophilic groups such as hydroxyalkylene groups; and so on.

[0035] The raw materials for acetalized sugars, the sugars forming the backbone of the acetalized sugars, may have cross-linking structures derived from polyhydric alcohols or polyhydric carboxylic acids in their sugar chains. Examples of polyhydric alcohols include sugar alcohols such as sorbitol, mannitol, xylitol, maltitol, and erythritol; glycerin; etc. Examples of polyhydric carboxylic acids include citric acid.

[0036] The sugars used as raw materials for acetalized sugars are more preferably selected from pullulan, dextrin, and cyclodextrin.

[0037] The sugars used as raw materials for acetalized sugars are preferably water-soluble dietary fiber. Water-soluble dietary fiber has multiple hydroxyl groups in its molecule, thus having high water solubility, and these hydroxyl groups can be modified into acetal groups. Furthermore, water-soluble dietary fiber has many branched structures in its sugar chain, making it suitable as a raw material for acetalized sugars, which have high polymerizability. From the viewpoint of easily preparing a low-viscosity aqueous composition, the sugars used as raw materials for the acetalized sugars are preferably water-soluble dietary fiber that forms a low-viscosity aqueous solution. Examples of water-soluble dietary fiber that forms a low-viscosity aqueous solution include indigestible dextrin, isomaltodextrin, dextrose, and polydextrose, with indigestible dextrin or dextrose being preferred.

[0038] The raw material sugars may be sugars that have been modified beforehand by processes such as enzymatic decomposition and acid treatment. Alternatively, the raw material sugars may be sugars that have been purified and fractionated beforehand by processes such as reprecipitation.

[0039] The weight-average molecular weight (Mw) of the raw sugars should be selected according to the intended use of the acetalized sugars. The weight-average molecular weight (Mw) of the raw sugars is preferably 200 or more, more preferably 500 or more, and even more preferably 1500 or more. For example, the weight-average molecular weight (Mw) of the raw sugars is preferably 400,000 or less, and more preferably 200,000 or less. It is preferable that the weight-average molecular weight (Mw) of the acetalized sugars is 400,000 or less. Similar to the weight-average molecular weight (Mw) of the acetalized sugars, the weight-average molecular weight of the raw sugars is measured by gel permeation chromatography (GPC) as a value equivalent to standard polystyrene.

[0040] [Olefin ether compounds] Compounds for forming an acetal group include olefin ether compounds in which an alkoxy group is ether-bonded to the carbon constituting the unsaturated double bond of an olefin, and preferably vinyl ether compounds. The vinyl ether compounds may be alkyl-containing vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, tert-butyl vinyl ether, 4-cyclopentyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, and cyclohexylmethyl vinyl ether, and may be aromatic-containing vinyl ether compounds such as phenyl vinyl ether and benzyl vinyl ether.

[0041] Besides vinyl ether compounds, other examples of olefin ether compounds include 1-methoxypropylene, 2-methoxy-2-butene, 2-methoxy-3-methyl-2-butene, and 2-(ethenyloxy)bicyclo[2.2.1]heptane.

[0042] The olefin ether compound preferably has a molecular weight of 50 or more, and more preferably 75 or more. The higher the molecular weight of the compound for forming the acetal group is above 50, the greater the swelling resistance of the acetalized sugar to water. Also, for example, when the acetalized sugar is used as the base resin of a resist, high exposure sensitivity can be obtained. Furthermore, the compound for forming the acetal group preferably has a molecular weight of 500 or less, and more preferably 150 or less. The lower the molecular weight of the allylalkoxy compound is below 500, the more quickly the hydroxyl group of the sugar can be converted to an acetal group.

[0043] The amount of allyl alkoxy compound used in the production of acetalized sugars should be appropriately determined according to the amount of sugar used, the amount of hydroxyl groups present in the sugar, and the desired denaturation rate. The amount of hydroxyl groups present in the sugar can be, for example, 13The integral value can be calculated by taking the ratio of the integral value at the carbon atom to which the hydroxyl group is attached in the sugar chain of the acetalized sugar, as measured by 13C-NMR, to the integral value at the peak of a specific carbon atom originating from the acetal group.

[0044] [Organic solvents] The organic solvent used in the method for producing acetalized sugars should be an organic solvent that can dissolve the sugars and the olefin ether compound, and does not react with the sugars and the denaturant. The organic solvent is preferably an aprotic polar solvent. Examples of aprotic polar solvents include N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and dimethylacetamide (DMAc), and Examples include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl (MIBK), ethers such as dioxane and tetrahydrofuran, lactones such as γ-butyl lactone, and esters.

[0045] 〔catalyst〕 Catalysts for acetalizing sugars include acid catalysts, such as trifluoroacetic acid and p-toluenesulfonic acid, with trifluoroacetic acid being preferred. The amount of catalyst used can be designed according to the type of sugar, the desired denaturation rate, etc., and is not limited, but the catalyst concentration in the reaction solution should be around 0.01 to 2.0% by weight.

[0046] [Reaction environment] In the reaction between sugars and olefin ether compounds, the system temperature of the reaction solution is preferably -10°C or higher, and more preferably 0°C or higher. This allows for easy temperature control during the reaction with the denaturing agent. Furthermore, during the reaction with the denaturing agent, the system temperature is preferably 100°C or lower, and more preferably 60°C or lower.

[0047] The reaction between sugars and olefin ether compounds may be carried out under an atmospheric or inert gas atmosphere. The reaction with the denaturing agent is not limited, but is preferably carried out under an inert gas atmosphere. Examples of inert gases include nitrogen gas and argon gas.

[0048] In the reaction between sugars and olefin ether compounds, the acid produced as a byproduct may be neutralized by adding an amine to the system after the reaction is complete. Examples of amines include tertiary amines such as triethylamine.

[0049] The obtained acetalized sugars are preferably purified using a mixed solvent of water and an organic solvent. Here, the organic solvent should be one that is immiscible with water at room temperature (around 23°C). For example, ketones such as methyl isobutyl ketone (MIBK), esters such as ethyl acetate, and ethers such as dioxane can be used.

[0050] <Photosensitive composition> A photosensitive composition according to one aspect of the present invention may contain acetalized sugars according to one aspect of the present invention as a base resin for the photosensitive composition, and preferably contain a photoacid generator as a photosensitive agent. By containing acetalized sugars and a photoacid generator, the photosensitive composition can be suitably used, for example, as a positive-type resist composition. Furthermore, the photosensitive composition may more preferably contain an organic solvent and a quencher.

[0051] Examples of acetalized sugars according to one aspect of the present invention in the photosensitive composition, as well as preferred embodiments, have already been described and will not be repeated here.

[0052] The photosensitive agent contained in the photosensitive composition according to one aspect of the present invention is typically a photoacid generator. The photosensitive agent may be one type or a combination of two or more types.

[0053] The photoacid generator can be any known photoacid generator and is not limited to it, but examples include onium salt-based photoacid generators, diazomethane derivatives, nitrobenzyl sulfonate derivatives, and disulfone-based acid generators. The acid generator may be used alone or in combination of two or more acid generators.

[0054] Examples of onium salt-based photoacid generators include salts of sulfonium cations or iodonium cations with anions such as sulfonates, bis(substituted alkylsulfonyl)imides, or tris(substituted alkylsulfonyl)methides. Examples include sulfonium salts such as triphenylsulfonium trifluoromethanesulfonic acid, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonic acid, and bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonic acid; iodonium salts such as diphenyliodonium trifluoromethanesulfonic acid and (p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonic acid; and ammonium salts such as tetramethylammonium trifluoromethanesulfonic acid.

[0055] Examples of diazomethane derivatives include bisarylsulfonyl diazomethanes such as bis(benzenesulfonyl)diazomethane and bis(p-toluenesulfonyl)diazomethane; and bisalkylsulfonyl diazomethanes such as bis(cyclohexylsulfonyl)diazomethane.

[0056] Other examples of acid generators include nitrobenzyl sulfonate derivatives such as p-toluenesulfonic acid 2,6-dinitrobenzyl and p-toluenesulfonic acid 2,4-dinitrobenzyl; bissulfone derivatives such as bisnaphthylsulfonylmethane; and sulfonic acid ester derivatives of N-hydroxyimide compounds such as N-hydroxysuccinidomethanesulfonic acid ester, N-hydroxysuccinidomitetrifluoromethanesulfonic acid ester, N-hydroxysuccinidomitep-toluenesulfonic acid ester, and N-hydroxynaphthalimidemethanesulfonic acid ester.

[0057] The content of the acetalized sugars in the photosensitive composition is preferably 5% by weight or more, more preferably 20% by weight or more, and even more preferably 30% by weight or more, based on the total weight of the photosensitive composition. Furthermore, in terms of reducing the viscosity of the photosensitive composition and improving coating properties, the content of the acetalized sugars is preferably 50% by weight or less, and more preferably 40% by weight or less.

[0058] The amount of photosensitive agent contained in the photosensitive composition is preferably 0.01 parts by weight or more, and more preferably 0.1 parts by weight or more, based on 100 parts by weight of acetalized sugars. Furthermore, the amount of photosensitive agent contained in the photosensitive composition is preferably 100 parts by weight or less, and more preferably 10 parts by weight or less, based on 100 parts by weight of acetalized sugars.

[0059] [Quencher] The photosensitive composition preferably contains a quencher. The inclusion of a quencher in the photosensitive composition suppresses the rapid diffusion rate of acid generated from the photoacid generator in a film containing acetalized sugars as a base resin. This improves the resolution of the pattern when the film containing acetalized sugars is exposed. Therefore, environmentally dependent post-exposure sensitivity changes can be reduced, improving exposure condition alignment and pattern profile.

[0060] Quenchers include nitrogen-containing organic compounds, which include primary, secondary, and tertiary aliphatic amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. Specifically, primary aliphatic amines include ethylamine, hexylamine, cyclohexylamine, ethylenediamine, and tetraethylenepentamine; secondary aliphatic amines include diethylamine, dibutylamine, dihexylamine, dicyclohexylamine, and N,N-dimethyltetraethylenepentamine; and tertiary aliphatic amines include triethylamine, tripropylamine, tributylamine, trihexylamine, tricyclohexylamine, N,N,N',N'-tetramethylmethylenediamine and N,N,N',N'-tetramethyltetraethylenepentamine.

[0061] Aromatic amines include, for example, aniline and its derivatives such as aniline, N-methylaniline, and N-ethylaniline. Heterocyclic amines include pyrrole, oxazole, imidazole, pyrazole, furazan, pyrroline, pyrrolidine, imidazoline, and its derivatives. Derivatives of pyrrolidine include N-methylpyrrolidine, pyrrolidinone, and N-methylpyrrolidone.

[0062] Examples of nitrogen-containing compounds having a carboxyl group include aminobenzoic acid, and examples of nitrogen-containing compounds having a sulfonyl group include 3-pyridinesulfonic acid and pyridinium p-toluenesulfonate. Examples of nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, and alcoholic nitrogen-containing compounds include 2-hydroxypyridine, 2-aminoethanol, 3-amino-1-propanol, and 4-amino-1-butanol.

[0063] The amount of quencher can be appropriately designed depending on the type of acetalized sugars and photosensitive agent, and is not limited, but for example, it is preferably 0 to 50 parts by weight, and more preferably 0 to 40 parts by weight, based on 100 parts by weight of acetalized sugars contained in the photosensitive composition.

[0064] [Other ingredients] A photosensitive composition according to one aspect of the present invention may contain, to the extent that the effects of the present invention are not impaired, other components such as a diluent; a crosslinking agent; a surfactant; a reaction inhibitor; an adhesion aid; a filler; a pH adjuster; a pH buffer; and other additives such as a water-soluble resin. The other components may be one or a combination of two or more.

[0065] (Diluting solvent) The diluent included in the photosensitive composition is not limited, but is often an organic solvent, and preferably an amphiphilic solvent. Examples of amphiphilic solvents include monoalcohols such as ethanol, methanol, acetonitrile, and propanol; polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, trimethylene glycol, diethylene glycol, polyethylene glycol, and glycerin; and 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol. Examples of diluent solvents include glycol ethers such as ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl methyl ether, ethylene glycol monophenyl ether, and propylene glycol methyl ether (PGME); cyclic ethers such as 1,3-dioxane and 1,4-dioxane; glycol esters such as propylene glycol 1-monomethyl ether 2-acetate (PGMEA); and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Other organic solvents include aromatic hydrocarbons such as toluene and xylene, and polar solvents such as N-methyl-2-pyrrolidone. These diluent solvents may be used individually or in combination of two or more. The photosensitive composition may also contain water as a mixed solvent with the diluent solvent. For example, the water content in the photosensitive composition can be appropriately selected depending on the desired viscosity of the photosensitive composition and the film thickness obtained by coating with the photosensitive composition.

[0066] (Surfactants) By including an appropriate amount of surfactant in the photosensitive composition, the surface tension of the photosensitive composition can be arbitrarily adjusted, improving the leveling properties during coating and enhancing the uniformity of the coating film thickness.

[0067] Examples of surfactants included in the photosensitive composition include fluororesin-based surfactants, silicone-based surfactants, polyoxyalkylene ether-based surfactants, and acrylic resin-based surfactants.

[0068] In the photosensitive composition, the surfactant content is preferably 0.01 parts by weight or more, and more preferably 0.30 parts by weight or more, based on 100 parts by weight of acetalized sugars. Furthermore, in the photosensitive composition, the surfactant content is preferably 10.00 parts by weight or less, and more preferably 5.00 parts by weight or less, based on 100 parts by weight of acetalized sugars.

[0069] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0070] 〔summary〕 The acetalized sugars according to an aspect of the present disclosure [1] are obtained by modifying at least a portion of the hydroxyl groups of the sugars into acetal groups.

[0071] In the acetalized sugars according to aspect [2] of the present disclosure, it is more preferable that the weight-average molecular weight is 200 or more and 400,000 or less in aspect [1].

[0072] In the acetalized sugars according to aspect [3] of the present disclosure, it is more preferable that, in aspect [1] or [2], the total amount of hydroxyl groups in the sugar is 100 mol%, and 40 mol% or more of the hydroxyl groups are modified into acetal groups.

[0073] In any of the embodiments [4] of the present disclosure, the acetalized sugars are more preferably such that the sugar is at least one sugar selected from dextrin, indigestible dextrin, and pullulan.

[0074] In any of the embodiments [1] to [4] of the present disclosure, the acetalized sugars according to embodiment [5] are more preferably such that the acetal group is derived from a vinyl ether compound. In any of the embodiments [1] to [5] of the present disclosure, the acetalized sugars are more preferably selected from the group consisting of ethyl vinyl ether and cyclohexyl vinyl ether.

[0075] A photosensitive composition according to an aspect of the present disclosure [7] comprises any of the acetalized sugars of aspects [1] to [6] and a photoacid generator.

[0076] The photosensitive composition according to an aspect of the present disclosure [8] is more preferably further comprising an organic solvent in the aspect [7].

[0077] A photosensitive composition according to an aspect of the present disclosure [9] is more preferably further comprising a quencher in the aspect [7] or [8].

[0078] The photosensitive composition according to an aspect of the present disclosure

[10] may be a positive-type resist composition in the aspects [7] to [9] described above. [Examples]

[0079] One embodiment of the present invention is described below. [Measurement of weight-average molecular weight (Mw)] For the GPC (gel permeation chromatography) measurement device, we used the "HLC-8120GPC" (a registered trademark of Tosoh Corporation) manufactured by Tosoh Corporation. The column consisted of three linked columns (each manufactured by Tosoh Corporation, with product names "TSKgel G3000HHR", "TSKgel G2000HHR", and "TSKgel G2000HHR"; "TSKgel" is a registered trademark of Tosoh Corporation). Tetrahydrofuran (THF) was used as the mobile phase for the GPC measurement, and polystyrene (TSKgel standard Polystyrene, manufactured by Tosoh Corporation) was used as the standard substance.

[0080] Table 1 shows the weight-average molecular weights of the raw materials, which are sugars, determined under the conditions described above.

[0081] <1> Sample preparation <Example 1> First, a 1L reaction vessel equipped with a thermometer, stirrer, and condenser was prepared. 25.0g of NSD500S (dextrin, manufactured by San-ei Sugar Refining Co., Ltd.) and 58.3g of N-methylpyrrolidone (NMP) were charged into the reaction vessel to prepare the solution. Next, residual water in the solution was removed under vacuum conditions of -740mmHg and heating conditions of 50°C. After cooling the solution to 30°C, the solution was replaced with nitrogen gas. Subsequently, 5.28g (0.046mol) of trifluoroacetic acid was added to the solution as the reaction mixture, followed by the dropwise addition of 26.5g (0.368mol) of ethyl vinyl ether over 1 hour. After the dropwise addition, the reaction was continued for 3 hours while maintaining the temperature of the solution at 30°C. Then, 4.65g (0.046mol) of triethylamine was added to the reaction mixture to neutralize it. Methyl isobutyl ketone (MIBK) and deionized water were added to the reaction mixture after neutralization, thereby transferring the neutralized salt and N-methylpyrrolidone to the aqueous phase and purifying the product, 80% acetal-modified dextrin. The phase containing methyl isobutyl ketone was concentrated by raising the temperature to approximately 70°C under a vacuum of -740 mmHg to obtain a solution (hereafter TOA-DE80) with a concentration of 15% by weight of 80% acetal-modified dextrin.

[0082] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-DE80, as determined by 13C-NMR (measured value), was 70 mol%.

[0083] The weight-average molecular weight of TOA-DE80, as determined by GPC analysis, was 19700 (based on standard polystyrene).

[0084] To prepare the photosensitive composition TOA-DE805, 100 parts by weight of acetal-modified dextrin in TOA-DE80 was used, and 5.0 parts by weight of triphenylsulfonium trifluorosulfonate and 0.5 parts by weight of n-octylamine were added. To prepare the photosensitive composition TOA-DE8010, 100 parts by weight of acetal-modified dextrin in TOA-DE80 was used, and 10.0 parts by weight of triphenylsulfonium trifluorosulfonate and 1.0 part by weight of n-octylamine were added.

[0085] <Example 2> Dextrin (NSD500S) was acetal-modified by performing the same procedure as in Example 1, except that the amount of ethyl vinyl ether was changed from 26.5 g (0.368 mol) to 33.2 g (0.460 mol). This yielded a solution (hereafter TOA-DE100) in which the concentration of 100% acetal-modified dextrin was 15% by weight.

[0086] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-DE100, as determined by 13C-NMR (measured value), was 90 mol%.

[0087] The weight-average molecular weight of TOA-DE100, as determined by GPC analysis, was 22,500 (based on standard polystyrene).

[0088] TOA-DE1005 was prepared by adding 5.0 parts by weight of triphenylsulfonium trifluorosulfonate and 0.5 parts by weight of n-octylamine to 100 parts by weight of acetal-modified dextrin in TOA-DE100. Furthermore, TOA-DE10010 was prepared by adding 10.0 parts by weight of triphenylsulfonium trifluorosulfonate and 1.0 part by weight of n-octylamine to 100 parts by weight of acetal-modified dextrin in TOA-DE100.

[0089] <Example 3> In a reaction vessel similar to that of Example 1, 25.0 g of Fibersol® 2 (indigestible dextrin, manufactured by Matsutani Chemical Industry Co., Ltd.) and 58.3 g of N-methylpyrrolidone were charged, and the solution was obtained by performing the same operations as in Example 1, from dehydration of the solution to substitution with nitrogen gas. Then, using this solution as the reaction mixture, 5.28 g (0.046 mol) of trifluoroacetic acid was added, followed by the dropwise addition of 23.2 g (0.322 mol) of ethyl vinyl ether over 1 hour. After the dropwise addition, the reaction was continued for 3 hours while maintaining the temperature of the solution at 30°C. Subsequently, 4.65 g (0.046 mol) of triethylamine was added to the reaction mixture to neutralize it.

[0090] Methyl isobutyl ketone and deionized water were added to the reaction solution after neutralization, thereby transferring the neutralized salt and N-methylpyrrolidone to the aqueous phase, and the 70% acetal modified product of indigestible dextrin was purified. The phase containing methyl isobutyl ketone was concentrated by raising the temperature to approximately 70°C under a vacuum of -740 mmHg, and a solution (hereafter TOA-FE70) with a concentration of 15% by weight of the 70% acetal modified product of indigestible dextrin was obtained.

[0091] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-FE70, as determined by 13C-NMR, was 60 mol% (measured value).

[0092] The weight-average molecular weight of TOA-FE70, as determined by GPC analysis, was 2200 (based on standard polystyrene).

[0093] To prepare the photosensitive composition TOA-FE705, 100 parts by weight of the acetal-modified product in TOA-FE70 was used, and 5.0 parts by weight of triphenylsulfonium trifluorosulfonate and 0.5 parts by weight of n-octylamine were added. In addition, to prepare the photosensitive composition TOA-FE7010, 100 parts by weight of the acetal-modified dextrin in TOA-FE70 was used, and 10.0 parts by weight of triphenylsulfonium trifluorosulfonate and 1.0 part by weight of n-octylamine were added.

[0094] <Example 4> Indigestible dextrin (Fibersol 2) was acetal-modified by performing the same procedure as in Example 3, except that the amount of ethyl vinyl ether was changed from 23.2 g (0.322 mol) to 26.5 g (0.368 mol). This yielded a solution (hereafter TOA-FE80) in which the concentration of 80% acetal-modified indigestible dextrin was 15% by weight.

[0095] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-FE80, as determined by 13C-NMR, was 70 mol% (measured value).

[0096] The weight-average molecular weight of TOA-FE80, as determined by GPC analysis, was 2600 (based on standard polystyrene).

[0097] To prepare the photosensitive composition TOA-FE805, 100 parts by weight of the acetal-modified material in TOA-FE80 was used, and 5.0 parts by weight of triphenylsulfonium trifluorosulfonate and 0.5 parts by weight of n-octylamine were added. In addition, to prepare the photosensitive composition TOA-FE8010, 100 parts by weight of the acetal-modified material in TOA-FE80 was used, and 10.0 parts by weight of triphenylsulfonium trifluorosulfonate and 1.0 part by weight of n-octylamine were added.

[0098] <Example 5> Indigestible dextrin (Fibersol 2) was acetal-modified by performing the same procedure as in Example 3, except that the amount of ethyl vinyl ether was changed from 23.2 g (0.322 mol) to 33.2 g (0.460 mol). This yielded a solution (hereafter TOA-FE100) in which the concentration of 100% acetal-modified indigestible dextrin was 15% by weight.

[0099] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-FE100, as determined by 13C-NMR, was 90 mol% (measured value).

[0100] The weight-average molecular weight of TOA-FE10, as determined by GPC analysis, was 3600 (based on standard polystyrene). To prepare the photosensitive composition TOA-FE1005, 100 parts by weight of the acetal-modified material in TOA-FE100 was used, and 5.0 parts by weight of triphenylsulfonium trifluorosulfonate and 0.5 parts by weight of n-octylamine were added. In addition, to prepare the photosensitive composition TOA-FE10010, 100 parts by weight of the acetal-modified material in TOA-FE100 was used, and 10.0 parts by weight of triphenylsulfonium trifluorosulfonate and 1.0 part by weight of n-octylamine were added.

[0101] <Example 6> Dextrin (NSD500S) was acetal-modified by performing the same procedure as in Example 1, except that 26.5 g (0.368 mol) of ethyl vinyl ether was replaced with 46.7 g (0.368 mol) of cyclohexyl vinyl ether. This yielded a solution (hereafter TOA-DC80) in which the concentration of the 80% acetal-modified dextrin was 15% by weight.

[0102] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-DC80 (measured value) was 70 mol% as determined by 13C-NMR measurement.

[0103] The weight-average molecular weight of TOA-DC80, as determined by GPC analysis, was 20800 (based on standard polystyrene). To prepare the photosensitive composition TOA-DC805, 100 parts by weight of the acetal-modified material in TOA-DC80 was used, and 5.0 parts by weight of triphenylsulfonium trifluorosulfonate and 0.5 parts by weight of n-octylamine were added. To prepare the photosensitive composition TOA-DC8010, 100 parts by weight of the acetal-modified material in TOA-DC80 was used, and 10.0 parts by weight of triphenylsulfonium trifluorosulfonate and 1.0 part by weight of n-octylamine were added.

[0104] <Example 7> In a reaction vessel similar to that of Example 1, 25.0 g of pullulan (manufactured by Hayashibara Co., Ltd.) and 225 g of N-methylpyrrolidone were charged, and the solution was obtained by performing the same operations as in Example 1, from dehydration of the solution to replacement with nitrogen gas. Then, using this solution as the reaction mixture, 5.28 g (0.046 mol) of trifluoroacetic acid was added, followed by the dropwise addition of 26.5 g (0.368 mol) of ethyl vinyl ether over 1 hour. After the dropwise addition, the reaction was continued for 3 hours while maintaining the temperature of the solution at 30°C. Subsequently, 4.65 g (0.046 mol) of triethylamine was added to the reaction mixture to neutralize it.

[0105] Methyl isobutyl ketone and deionized water were added to the reaction mixture after neutralization, thereby transferring the neutralized salt and N-methylpyrrolidone to the aqueous phase and purifying the 80% acetal modified pullulan. The phase containing methyl isobutyl ketone was concentrated by raising the temperature to approximately 70°C under a vacuum of -740 mmHg to obtain a solution (hereafter TOA-PE80) with a concentration of 10% by weight of the 80% acetal modified pullulan.

[0106] 13 The denaturation rate of acetal groups relative to hydroxyl groups in TOA-PE80 (measured value) was 73 mol% by 13C-NMR measurement.

[0107] The weight-average molecular weight of TOA-PE80, determined by GPC analysis, was 250,000 (based on standard polystyrene).

[0108] To prepare the photosensitive composition TOA-PE8030, 100 parts by weight of the acetal-modified product in TOA-PE80 was used, and 30.0 parts by weight of triphenylsulfonium trifluorosulfonate and 3.0 parts by weight of n-octylamine were added.

[0109] <Comparative Example 1> A 1L reaction vessel was prepared, and 100.0g of NSD500S (dextrin, manufactured by San-ei Sugar Refining Co., Ltd.) and 185.7g of N-methylpyrrolidone were charged into the vessel to prepare a solution. Next, the water remaining in the solution was removed under a vacuum of -740mmHg and heating conditions of 40°C. Then, the solution was cooled to 15°C, and while keeping the temperature below 15°C, 50.4g (0.56mol) of acrylate chloride was added dropwise over 2 hours, and the reaction was continued for 2 hours while maintaining cooling. Subsequently, 56.2g (0.56mol) of triethylamine was added to the reaction mixture to neutralize it. After that, the neutralized salt and N-methylpyrrolidone were removed by purification, thereby obtaining a 30% acrylic acid modified dextrin. Subsequently, deionized water was added to achieve a concentration of 25% by weight of the acrylic acid modified product, and a 30% acrylic acid modified water-soluble dextrin solution (hereafter referred to as Dx30) was obtained.

[0110] To prepare photosensitive composition Dx30-3, 3.0 parts by weight of a photosensitive agent (Omnirad® 2959 (manufactured by IGM Resins BV)) was added to 100 parts by weight of the acrylic acid modified product in Dx30.

[0111] <Comparative Example 2> 100.0 g of Fibersol® 2 (indigestible dextrin, manufactured by Matsutani Chemical Industry Co., Ltd.) and 185.7 g of N-methylpyrrolidone were charged into a 1 L reaction vessel, and a solution was obtained by dehydration under the same conditions as in Comparative Example 1. Next, this solution was used as the reaction solution, cooled to 15°C, and while keeping the temperature below 15°C, 50.4 g (0.56 mol) of acrylate chloride was added dropwise over 2 hours, and the reaction was continued for 2 hours while maintaining cooling. Then, 56.2 g (0.56 mol) of triethylamine was added to the reaction solution to neutralize it. Subsequently, the neutralized salt and N-methylpyrrolidone were removed by purification, thereby obtaining a 30% acrylic acid modified product of indigestible dextrin. Then, ion-exchanged water was added so that the concentration of the acrylic acid modified product was 25% by weight, and a water-soluble aqueous varnish of 30% acrylic acid modified product of indigestible dextrin (hereafter FB30) was obtained.

[0112] To prepare photosensitive composition FB30-3, 100 parts by weight of the acrylic acid modified product in FB30 was used, and 3.0 parts by weight of a photosensitive agent (Omnirad® 2959 (manufactured by IGM Resins BV)) was added.

[0113] <Comparative Example 3> 100 g of pullulan (manufactured by Hayashibara Co., Ltd.) and 900 g of N-methylpyrrolidone were charged into a 2 L reaction vessel, and a solution was obtained by dehydration under the same conditions as in Comparative Example 1. Next, this solution was used as the reaction mixture, cooled to 15°C, and while keeping the temperature below 15°C, 50.4 g (0.56 mol) of acrylate chloride was added dropwise over 2 hours, and the reaction was continued for 2 hours while maintaining cooling. Subsequently, 56.2 g (0.56 mol) of triethylamine was added to the reaction mixture to neutralize it. Then, the neutralized salt and N-methylpyrrolidone were removed by purification, thereby obtaining a 30% acrylic acid modified product of pullulan. Subsequently, ion-exchanged water was added so that the concentration of the acrylic acid modified product was 10% by weight, and a water varnish of 30% acrylic acid modified water of water-soluble indigestible dextrin (hereafter P30) was obtained.

[0114] To prepare photosensitive composition P30-3, 3.0 parts by weight of a photosensitive agent (Omnirad® 2959 (manufactured by IGM Resins BV)) was added to 100 parts by weight of the acrylic acid modified product in P30.

[0115] <2> Each evaluation <2-1> Exposure Sensitivity Evaluation The exposure sensitivity of each of the photosensitive compositions in Examples 1 to 6 was evaluated.

[0116] Preparation of test specimens: 3 ml of photosensitive composition was dropped onto a silicon wafer, mounted on a spinner (CLEAN TRACK ACT8; manufactured by Tokyo Electron Limited), and spin-coated at 3000 rpm for 30 seconds to coat the silicon wafer with the photosensitive composition. Subsequently, the silicon wafer coated with the photosensitive composition was heated at 110°C for 60 seconds to volatilize and remove the solvent contained in the photosensitive composition, forming a resist film. This created a test specimen for evaluating exposure sensitivity.

[0117] Using the mask contact exposure apparatus and sensitivity confirmation mask described below, 70-3000 mJ / cm² 2 The resist film was exposed under the specified exposure conditions and developed with pure water. The film thickness before and after development was measured, and the exposure sensitivity was evaluated as the time (seconds) required to expose a predetermined film thickness. Mask contact exposure system: LTCET-500 (manufactured by Lithotech Japan Co., Ltd.) Sensitivity verification mask: 5-inch multi-transmission mask (manufactured by Taiyo Ink Manufacturing Co., Ltd.) Table 1 shows the photosensitive compositions subjected to exposure sensitivity testing and the results of the exposure sensitivity evaluation.

[0118] [Table 1]

[0119] As shown in Table 1, it was confirmed that each of the photosensitive compositions in Examples 1 to 7 could obtain good exposure sensitivity. The fact that the exposure sensitivity of each photosensitive composition in Examples 1 to 6 was higher than that of the photosensitive composition in Example 7 is judged to be due to the smaller weight-average molecular weight of dextrin and indigestible dextrin compared to pullulan. Also, as shown in Table 1, the photosensitive compositions in Examples 4 and 5 showed exposure sensitivity equivalent to that of the photosensitive compositions in Examples 1 and 2, despite having a smaller weight-average molecular weight of acetalized sugars compared to Examples 1 and 2. Since a smaller weight-average molecular weight makes a substance more easily soluble in water, which is the developing solution, it is thought that the photosensitive compositions in Examples 4 and 5, which have lower molecular weights, require a lower minimum exposure than the photosensitive compositions in Examples 1 and 2. In all of the photosensitive compositions in Examples 1 to 7, there was a tendency for the exposure sensitivity to decrease as the sugars containing a higher rate of acetal group conversion were increased. Furthermore, a comparison between the photosensitive composition TOA-DC8010 and the photosensitive composition TOA-DE8010 shows that acetalization with cyclohexyl vinyl ether results in higher exposure sensitivity.

[0120] <2-2> Resolution Evaluation Test specimens for evaluating the resolution of the examples were prepared under the same conditions as those used for evaluating exposure sensitivity. In the resolution evaluation, the resolution of the photosensitive compositions TOA-DE8010 and TOA-FE8010 of the examples was evaluated.

[0121] A resist film was formed under the same conditions as the photosensitive composition of the example, except that the solvent contained in the comparative example's photosensitive composition was removed by heating at 80°C for 60 seconds.

[0122] Using the mask contact exposure apparatus and resolution confirmation mask described below, the embodiment uses a density of 100-3000 mJ / cm². 2 In the comparative example, the resist film was exposed under exposure conditions of 600, and then developed with pure water. The resolution was then evaluated. Mask contact exposure system: LTCET-500 (manufactured by Lithotech Japan Co., Ltd.) Resolution verification mask: Toppan Test Chart N01-PN (manufactured by Toppan Corporation) Table 2 shows the photosensitive compositions that underwent resolution evaluation and the results of the exposure sensitivity evaluation.

[0123] [Table 2]

[0124] As shown in Table 2, compared to the negative-type resist film of the comparative example, the positive-type resist film of the example demonstrated that, even when synthesized using the same sugars, it was possible to create high-resolution patterns with a lower exposure.

[0125] Furthermore, it is determined that the high resolution of the resist films formed using the photosensitive compositions of Examples 1, 4, and 7 is due to the high exposure sensitivity of these photosensitive compositions, as well as their high resistance to swelling in water.

[0126] <Evaluation of the feasibility of water-based development> Test specimens for evaluating the feasibility of water development were prepared under the same conditions as those used for evaluating exposure sensitivity. For the evaluation of water development feasibility, the resolution of the photosensitive compositions TOA-DE8010 and TOA-FE8010 from the examples was evaluated, and a positive-type resist agent GTS (novolac-type phenolic resin, manufactured by Gun-ei Chemical Industry Co., Ltd.) was used as a control. For the evaluation of water development feasibility, the same mask-contact exposure apparatus and sensitivity confirmation mask as used for exposure sensitivity evaluation were employed, at 200 mJ / cm². 2 The resist film was exposed under the specified exposure conditions and developed with pure water.

[0127] Table 3 shows the photosensitive compositions evaluated for their suitability for water development, along with the results of the exposure sensitivity evaluation.

[0128] [Table 3]

[0129] The results shown in Table 3 confirm that while conventional positive-type photosensitive compositions using resin as a base resin could not be developed with water, rather than an alkaline aqueous solution, the photosensitive compositions of the examples, which used sugar chains as a backbone, were developable with water. [Industrial applicability]

[0130] The acetalized sugars provided in this disclosure can be used, for example, as photosensitive materials such as photoresist materials.

Claims

1. Acetalized sugars are sugars in which at least some of the hydroxyl groups present in the sugar are modified into acetal groups.

2. The acetalized sugar according to claim 1, wherein the weight-average molecular weight is 200 or more and 400,000 or less.

3. The acetalized sugar according to claim 1, wherein the total amount of hydroxyl groups in the sugar is 100 mol%, and 40 mol% or more of the hydroxyl groups are modified into acetal groups.

4. The acetalized sugar according to claim 1, wherein the sugar is at least one sugar selected from dextrin, indigestible dextrin, and pullulan.

5. The acetalized sugars according to claim 1, wherein the acetal group is an acetal group derived from a vinyl ether compound.

6. The acetalized sugar according to claim 5, wherein the vinyl ether compound is selected from the group consisting of ethyl vinyl ether and cyclohexyl vinyl ether.

7. A photosensitive composition comprising the acetalized sugars described in claim 1 and a photoacid generator.

8. Furthermore, the photosensitive composition according to claim 7, comprising an organic solvent.

9. Furthermore, the photosensitive composition according to claim 7, further comprising a quencher.

10. A photosensitive composition according to any one of claims 7 to 9, which is a positive-type resist agent composition.

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