Polymers useful as surface leveling agents, method for producing the same, and article comprising the same

Abstract

To provide polymers useful as surface leveling agents, a method for producing the same, and an article comprising the same.SOLUTION: There is provided a copolymer comprising first polymerized units of the formula (1) and second polymerized units of the formula (2), wherein the first polymerized units and the second polymerized units are chemically different, and the copolymer is free of fluorine. [In the formula (1), R1 is H or a substituted or unsubstituted C1 to C6 alkyl group; and R2 is a substituted or unsubstituted C3 to C20 alkyl group that optionally includes one or more of -O-, -S-, -N-, -C(O)-, or -C(O)O-, -N-C(O)-, -C(O)-NR-(wherein R is H or a substituted or unsubstituted C1 to C6 alkyl group).] [In the formula (2), R3 is a substituted or unsubstituted C1 to C6 alkyl group that optionally includes one or more of -O-, -N-, -S-, -C(O)-, or -C(O)O-.]SELECTED DRAWING: None

Description

[Technical field]

[0001] Disclosed herein are polymers useful as surface leveling agents, methods for making same, and articles containing same. [Background technology]

[0002] Surface leveling agents (SLAs) are used in compositions for producing thin films and coating solutions. Surface leveling agents typically tend to migrate to the free surface (surface in contact with air) and promote surface leveling or surface smoothing. Surface leveling agents generally comprise polymers or oligomers that have a lower surface energy compared to other molecules in the solution, which allows them to selectively segregate to the free surface even at low solids loadings. This ability to migrate to the surface (i.e., molecular mobility) promotes the flow and leveling of the surface / interface layer, resulting in a flat smooth surface / interface.

[0003] The most common surface leveling agents contain polysiloxanes, alkyl modified acrylic polymers, polyesters or fluorocarbons. Good surface leveling agents have properties such as, for example, excellent slip, leveling, flow, surface tension reduction, anti-cratering ability, anti-fisheye ability, substrate wetting, tendency to prevent Benard cell formation, as well as good bubble stability.

[0004] Surface leveling agents play a vital role in various coating formulations, such as spin-on thin films that enable microlithography. With the need for ever increasing resolution of patterned features, aspect ratios, and low defect lithographic patterns, strategies to pursue new materials for surface leveling agents are desirable.

[0005] There are many reasons why defects are caused by surface leveling agents. Some of these are described below. Most surface leveling agents contain silicon or fluorine moieties and are highly hydrophobic. The hydrophobic nature of these surface leveling agents is unfortunately the main cause of defects in advanced photoresist patterning. These defects include not only surface defects but also other types such as residue precipitation, bridging defects, pattern undefined defects, etc.

[0006] Many lithographic patterning processes use wet base developers. Insoluble species in these base developers produce insoluble residues that cause defects. Therefore, it is desirable that any exposed resist material be completely removable and not leave behind insoluble residues that can potentially form defects.

[0007] To overcome this problem, surface leveling agent is used in photoresist composition in the smallest possible amount.Another way to use surface leveling agent is to modify the agent to contain base-soluble units or base-switchable functional groups to allow solubility.In other words, it is desirable to specially modify the surface leveling agent containing fluorine and / or silicon moieties for use in photoresist composition.

[0008] Another problem with fluorine-containing surface leveling agents is regulatory issues: government regulations require that fluorine-containing products be used at a minimum level.

[0009] It is therefore desirable to develop a surface leveling agent that can be used in compositions for lithographic or coating applications and that is non-fluorocarbon-containing and provides good surface leveling properties without causing defects in the resulting article. Summary of the Invention [Means for solving the problem]

[0010] Formula (1): [ka] [In the formula, R1 is H or a substituted or unsubstituted C1-C6 alkyl group, and R2 is a substituted or unsubstituted C3-C6 alkyl group optionally containing one or more of -O-, -S-, -N-, -C(O)-, -C(O)O-, -NC(O)-, -C(O)-NR- (R is H or a substituted or unsubstituted C1-C6 alkyl group). 20 and a first polymerized unit of Formula (2): [ka] and second polymerized units of the formula: wherein R3 is a substituted or unsubstituted C1-C6 alkyl group optionally containing one or more of -O-, -N-, -S-, -C(O)-, or -C(O)O-, wherein the first polymerized units and the second polymerized units are chemically distinct. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As used herein, the terms "a," "an," and "the" do not denote limitations of quantity and should be construed to include both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. "Or" means "and / or" unless otherwise stated.

[0012] As used herein, "acid labile group" refers to a group whose bond is cleaved by acid catalysis, optionally and typically by thermal treatment, resulting in a polar group, such as a carboxylic acid or alcohol group, formed in the polymer, and optionally and typically resulting in the moiety connected to the cleaved bond being detached from the polymer. Such acids are typically photogenerated acids whose bonds are cleaved during post-exposure bake. Suitable acid labile groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups with a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups or ketal groups. Acid labile groups are also commonly referred to in the art as "acid cleavable groups", "acid cleavable protecting groups", "acid labile protecting groups", "groups that are released with acid", "acid labile groups" and "groups that are sensitive to acid".

[0013] "Substituted" means that at least one hydrogen atom in a group is replaced with another atom or group, provided that the normal valence of the specified atom is not exceeded. When the substituent is oxo (i.e., =O), two hydrogens on a carbon atom are replaced. Combinations of substituents or variables are permitted. Exemplary groups that may be in a "substituted" position are nitro (-NO2), cyano (-CN), hydroxy (-OH), oxo (=O), amino (-NH2), mono- or di-(C 1~6 ) Alkylamino, alkanoyl (acyl, etc.) 2~6 alkanoyl group, etc.), formyl (-C(=O)H), carboxylic acid or their alkali metal or ammonium salts, C 2~6 Alkyl esters (-C(=O)O-alkyl or -OC(=O)-alkyl) and C 7~13 Esters (including acrylates, methacrylates and lactones), such as aryl esters (-C(=O)O-aryl or -OC(=O)-aryl), amides (-C(=O)NR2, where R is hydrogen or C 1~6 alkyl), carboxamide (-CH2C(=O)NR2 (R is hydrogen or C 1~6 Alkyl), halogen, thiol (-SH), C 1~6Alkylthio (-S-alkyl), thiocyano (-SCN), C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 1~6 Haloalkyl, C 1~9 Alkoxy, C 1~6 Haloalkoxy, C 3~12 Cycloalkyl, C 5~18 Cycloalkenyl, C having at least one aromatic ring (e.g., phenyl, biphenyl, naphthyl, etc., each ring being substituted or unsubstituted aromatic). 6~12 Aryl, C having 1-3 separated or fused rings and 6-18 ring carbon atoms 7~19 Arylalkyl, arylalkoxy having 1-3 separated or fused rings and 6-18 ring carbon atoms, C 7~12 Alkylaryl, C 4~12 Heterocycloalkyl, C 3~12 Heteroaryl, C 1~6 Alkylsulfonyl (-S(=O)2-alkyl), C 6~12 Examples of such radicals include, but are not limited to, arylsulfonyl (-S(=O)2-aryl) or tosyl (CH3C6H4SO2-). If a group is substituted, the indicated number of carbon atoms is the total number of carbon atoms in the group, excluding the carbon atoms of any substituents. For example, the group -CH2CH2CN is a C2 alkyl group substituted with a cyano group.

[0014] In this specification, "(meth)acrylate" refers to "at least one of acrylate and methacrylate." Furthermore, "(meth)acrylic acid" refers to "at least one of acrylic acid and methacrylic acid."

[0015] The term "alkyl" as used herein means a branched or straight chain saturated aliphatic hydrocarbon group having the specified number of carbon atoms, typically 1 to about 12 carbon atoms. The term C1-C6 alkyl as used herein refers to an alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms. Other embodiments include alkyl groups having 1 to 8 carbon atoms, 1 to 4 carbon atoms, or 1 or 2 carbon atoms, such as C1-C6 alkyl, C1-C4 alkyl, and C1-C2 alkyl. C0-C n When alkyl is used herein in conjunction with another group, for example, (cycloalkyl)C0-C4 alkyl, the indicated group, in this case cycloalkyl, is either directly attached by a single covalent bond (C0) or by an alkyl chain having the specified number of carbon atoms, in this case 1, 2, 3, or 4 carbon atoms. Examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, 3-methylbutyl, t-butyl, n-pentyl, and sec-pentyl.

[0016] The term "cycloalkyl," as used herein, refers to a saturated hydrocarbon ring group having only carbon ring atoms and having a specified number of carbon atoms, usually from 3 to about 8 ring carbon atoms, or from 3 to about 7 carbon atoms. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl as well as bridged or caged saturated ring groups such as norbornane or adamantane.

[0017] The term "heterocycloalkyl," as used herein, refers to a saturated cyclic group containing from 1 to about 3 heteroatoms selected from N, O, and S, with the remaining ring atoms being carbon. Heterocycloalkyl groups have from 3 to about 8 ring atoms, more typically 5 to 7 ring atoms. Examples of heterocycloalkyl groups include morpholinyl, piperazinyl, piperidinyl, and pyrrolidinyl groups. The nitrogen in a heterocycloalkyl group can be optionally quaternized.

[0018] In the present specification, when a group is described without specifying whether it is substituted or unsubstituted, the group includes both the group and the atomic group that does not have a substituent, and the group and the atomic group that has a substituent. For example, an "alkyl group" without specifying whether it is substituted or unsubstituted includes not only an alkyl group that does not have a substituent (an unsubstituted alkyl group), but also an alkyl group that has a substituent (a substituted alkyl group).

[0019] Disclosed herein is a surface leveling agent for use in surface active chemical applications, particularly lithographic compositions for producing spin-on thin films. The surface leveling agent comprises a copolymer of two or more polymer units having ether bonds in the backbone of the chain. The two or more polymer units do not contain fluorine. In an optional embodiment, the polymer does not contain a surface energy reducing moiety that contains silicon. Although the aforementioned ether bonds are part of the main chain of the polymer, there may be additional functional linkages in pendant groups (side chains) that are covalently attached to the main chain of the copolymer. In an embodiment, these side chains may contain only carbon-carbon bonds. In another embodiment, these side chains may contain carbon-carbon bonds in addition to other functional linkages or functional groups, such as, but not limited to, ether, ester, amide, sulfonate, hydroxy, thiol, cyano, amine, thiol, aldehyde, carboxyl, alkyl halide, ketone, allyl, allenyl, norbornyl, ethynyl, acrylate, methacrylate, itaconate, maleimide, maleic anhydride, and the like. In other words, the side chains can contain heteroatoms such as nitrogen, sulfur, oxygen, and the like.

[0020] Surface leveling agents may be used not only in compositions for lithographic applications, but also in other applications where good surface leveling and glossy appearance are desirable, such as coatings, paints, inks, plating solutions, medical, anti-corrosion, and lubrication technologies.

[0021] In a typical embodiment, at least one of the polymer units of the copolymer is a polyoxetane (hereinafter polyalkyloxetane) having at least one alkyl substituent along the backbone of the chain. The polyoxetane backbone provides hydrophilicity to the leveling agent copolymer, promoting miscibility with base and water, while the alkyl side chains provide hydrophobicity, allowing the leveling agent to migrate to the interface of a thin film or coating. The interface can be between a spin-on layer and air, or alternatively, between two layers of a multilayer film. In an embodiment, the polyalkyloxetane is present in the copolymer in an amount greater than 40 mole percent (mol%).

[0022] In embodiments, the polyoxetane copolymers may contain one or more terminal functional groups. The terminal functional groups may include hydroxyl, thiol, cyano, amine, or sulfonate.

[0023] The aforementioned alkyl substituents may be linear, branched, or may optionally contain other atoms such as O, S, N, P, or other functional linkages such as ether, ester, amide, imide, urethane, or urea. The alkyl substituents may also optionally contain terminal functional groups such as, for example, hydroxyl, thiol, cyano, amine, or sulfonate.

[0024] The surface leveling agent can be hydrophobic for certain applications, but sufficiently hydrophilic to be miscible with water or wet developers in other applications. The absence of fluorine or silicon-containing moieties in the surface leveling agent minimizes defect formation. The absence of fluorine-containing moieties meets environmental regulations.

[0025] The surface leveling agent is preferably a copolymer containing two or more different repeat units. In embodiments, the surface leveling agent can be a copolymer containing three or more different repeat units. The copolymer can be a random copolymer, an alternating copolymer, a block copolymer, a star block copolymer, a hyperbranched polymer, a comb copolymer, a dendrimer, a gradient copolymer, etc., but is preferably a random copolymer or a block copolymer. A combination of a random copolymer and a block copolymer can also be used in the surface leveling agent.

[0026] In an embodiment, the copolymer has the formula (1): [ka] [In the formula, R1 is H or a substituted or unsubstituted C1-C6 alkyl group, and R2 is a substituted or unsubstituted C3-C6 alkyl group optionally containing one or more of -O-, -S-, -N-, -C(O)-, -C(O)O-, -NC(O)-, -C(O)-NR- (R is H or a substituted or unsubstituted C1-C6 alkyl group). 20 and a first polymerized unit of formula (2): [ka] and second polymerized units of the formula: wherein R3 is a substituted or unsubstituted C1-C6 alkyl group optionally containing one or more of -O-, -N-, -S-, -C(O)-, or -C(O)O-, wherein the first polymerized units and the second polymerized units are chemically distinct and the copolymer does not contain fluorine. In a preferred embodiment, R3 is an unsubstituted C1-C5 alkyl.

[0027] When R3 is substituted, the chain length of the substituent has 2 or fewer carbon atoms. The hydrophilic polymer units of formula (2) can provide the advantage of surfactant leveling and miscibility with water or wet base developers.

[0028] In an embodiment, R2 has a branched structure. In an embodiment, R2 has two or more branches.

[0029] In embodiments, the surface leveling agent comprises polymerized units of formula (1), polymerized units of formula (2), and further polymerized units of formula (3). [ka] [wherein R4 is -O-, -S-, -N-, -C(O)-, or a substituted or unsubstituted C2 to C4 alkyl group optionally containing one or more of -C(O)O-, -NC(O)-, -C(O)-NR- (wherein R is H or a substituted or unsubstituted C1 to C6 alkyl group).

[0030] As a specific example of the above embodiment, the first polymerized unit is represented by formula (1-1), the second polymerized unit is represented by formula (2-1), and the third polymerized unit is represented by formula (4): [ka] (Wherein, R4 is a substituted or unsubstituted C3-C alkyl group optionally containing one or more of -O-, -S-, -N-, -C(O)-, or -C(O)O-. 20 alkyl group), [ka] It is expressed as:

[0031] Examples of precursors of the polymerized units of formula (1) include 3-methyloxetane, 3-ethyloxetane, 3-propyloxetane, 3-butyloxetane, 3-neopentyloxetane, 3-pentyloxetane, 3-hexyloxetane, 3-(2,2-dimethylbutyl)oxetane, 3-methoxymethyloxetane, 3-ethoxymethyloxetane, 3-propoxymethyloxetane, 3-butoxymethyloxetane, 3-neopentoxymethyloxetane, 3-pentoxymethyloxetane, 3-hexoxymethyloxetane, 3-(2,2-dimethylbutoxy)oxetane, 3-methoxyethyloxetane, 3-ethoxyethyloxetane, 3-propoxyethyloxetane, 3-butoxyethyloxetane, 3-neopentoxyethyloxetane, 3-pentoxyethyloxetane, 3-(1-methylethyl)-oxetane, or a combination thereof.

[0032] Examples of precursors of polymerized units of formula (2) include formaldehyde, ethylene oxide, propylene oxide, tetrahydrofuran, 1,4-dioxane, or combinations thereof.

[0033] Examples of precursors of polymerized units of formula (3) include 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or combinations thereof.

[0034] A preferred precursor of the polymerized units of formula (1) is 3-butyloxymethyl-3-methyloxetane, a preferred precursor of the polymerized units of formula (2) is tetrahydrofuran, and a preferred precursor of the polymerized units of formula (3) is 2,2-dimethyl-1,3-propanediol.

[0035] The surface leveling agent can have a weight average molecular weight of 500 to 30,000 grams per mole (g / mol), preferably 800 to 12,000 g / mol, and more preferably 1000 to 10,000 g / mol.

[0036] The polymerized units of formula (1) are typically present in the copolymer in an amount greater than 40 mol%, preferably greater than 50 mol%, and more preferably greater than 60 mol%, based on the total number of moles in the copolymer. The polymerized units of formula (1) are present in the copolymer in an amount less than 80 mol%, preferably less than 75 mol%, and more preferably greater than 70 mol%, based on the total number of moles in the copolymer.

[0037] In embodiments, the polymerized units of formula (2) are present in the copolymer in an amount greater than 20 mol%, preferably greater than 25 mol%, and more preferably greater than 70 mol%, based on the total number of moles in the copolymer. In embodiments, the polymerized units of formula (2) are present in the copolymer in an amount less than 60 mol%, preferably less than 50 mol%, and more preferably less than 40 mol%, based on the total number of moles in the copolymer.

[0038] In embodiments, the polymerized units of formula (3) are present in the copolymer in an amount of 0.01 mol % or more, preferably 1 mol % or more, and more preferably 2 mol % or more, based on the total number of moles in the copolymer. In embodiments, the polymerized units of formula (3) are present in the copolymer in an amount of 20 mol % or less, preferably 15 mol % or less, and more preferably 10 mol % or less, based on the total number of moles in the copolymer.

[0039] The surface leveling agent can be used in a variety of different compositions. In an embodiment, the surface leveling agent can be used in just the solvent or solvent mixture that acts as the rinse formulation. In another embodiment, the surface leveling agent can be used in a composition that includes the matrix polymer, the solvent, and other optional additives.

[0040] In embodiments, a surface leveling agent can be used in a photoresist composition containing a polymer matrix resin, an optional quencher, one or more photoacid generators, optional additives, and a solvent. The matrix polymer is preferably a copolymer containing at least one repeat unit that contains an acid labile group and / or that contains a crosslinkable functional group. If used, the surface leveling agent is present in an amount of 0.001 to 100 wt %, more preferably 0.001 to 1 wt %, based on the total solids content of the composition.

[0041] In another embodiment, the surface leveling agent can be used in a photoresist composition that contains, in addition to the surface leveling agent, a matrix polymer, a photoacid generator, an optional quencher, a solvent, and other optional additives.

[0042] In another embodiment, the surface leveling agent can be used in a composition containing a matrix polymer, at least one thermally activated acid generator, and a solvent in addition to the surface leveling agent.Other optional additives, such as, but not limited to, a crosslinking agent, can be added to the composition.Examples of compositions containing a thermally activated acid generator can be antireflective coating compositions, topcoats, photoresist trimming or pattern enhancing compositions, and other underlayer compositions.

[0043] The polymer matrix used in the aforementioned composition can include a thermoplastic polymer, a blend of thermoplastic polymers, a thermosetting polymer, or a blend of a thermoplastic polymer and a thermosetting polymer. The polymer matrix can also include a blend of polymers, copolymers, terpolymers, or a combination of at least one of the aforementioned polymers. The polymer matrix can also include oligomers, homopolymers, copolymers, block copolymers, alternating copolymers, random polymers, random copolymers, random block copolymers, gradient copolymers, graft copolymers, star block copolymers, dendrimers, polyelectrolytes (polymers with several repeat groups that contain electrolytes), polyampholytes (polyelectrolytes with both cationic and anionic repeat groups), ionomers, etc., or combinations thereof. The copolymers can be available as solute molecules, in the form of microparticles, or in the form of nanoparticle dispersions or suspensions in a solvent or solvent mixture.

[0044] Examples of thermoplastic polymers include polyacetals, polydienes, polyacrylics, polycarbonates, polyalkyds, polystyrenes, polyolefins, polyesters, polyamides, polyaramids, polyamideimides, polyarylates, polyurethanes, epoxies, phenols, silicones, polyarylsulfones, polyethersulfones, polyphenylene sulfides, polysulfones, polyimides, polyetherimides, polytetrafluoroethylenes, polyetherketones, polyetheretherketones, polyetherketoneketones, polybenzoxazoles, polyoxadiazoles, polybenzothiazinophenothiazines, polybenzothiazoles, polypyrazinoquinoxalines, polypyromellitimides, polyquinoxalines, Polybenzimidazoles, polyoxindoles, polyoxoisoindolines, polydioxoisoindolines, polytriazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polycarboranes, polyoxabicyclononanes, polydibenzofurans, polyphthalides, polyacetals, polyanhydrides, polyvinyl ethers, polyvinyl thioethers, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polysilazanes, polysiloxanes, and the like, or combinations thereof.

[0045] Examples of thermosetting polymers include epoxy polymers, unsaturated polyester polymers, polyimide polymers, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, vinyl polymers, benzoxazine polymers, benzocyclobutene polymers, acrylics, alkyds, phenol-formaldehyde polymers, novolacs, resoles, melamine-formaldehyde polymers, urea-formaldehyde polymers, hydroxymethylfurans, isocyanates, diallyl phthalates, triallyl cyanurates, triallyl isocyanurates, unsaturated polyesterimides, and the like, or combinations thereof. The composition may include a crosslinking agent to facilitate the formation of the thermosetting polymer. The crosslinking agent may be self-crosslinking, an acid or base activated crosslinking agent, a free radical crosslinking agent, or a combination thereof.

[0046] Suitable solvents include, for example, aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane and 1-chlorohexane, alcohols such as methanol, ethanol, 1-propanol, isopropanol, tert-butanol, 2-methyl-2-butanol and 4-methyl-2-pentanol, ethers such as propylene glycol monomethyl ether (PGME), diethyl ether, tetrahydrofuran, 1,4-dioxane and anisole, ketones such as acetone, methyl ethyl ketone, methyl iso-butyl ketone, 2-heptanone and cyclohexanone (CHO), ethyl acetate, and the like. , esters such as n-butyl acetate, propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), hydroxyisobutyric acid methyl ester (HBM) and ethyl acetoacetate, lactones such as γ-butyrolactone (GBL) and ε-caprolactone, lactams such as N-methylpyrrolidone, nitriles such as acetonitrile and propionitrile, cyclic or acyclic carbonate esters such as propylene carbonate, dimethyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate and propylene carbonate, polar aprotic solvents such as dimethylsulfoxide and dimethylformamide, water and combinations thereof. Of these, preferred solvents are PGME, PGMEA, EL, GBL, HBM, CHO and combinations thereof. The total solvent content in the composition (i.e., the cumulative solvent content of all solvents) is typically 40-99% by weight, such as 70-99% by weight or 85-99% by weight, based on the total weight of the photoresist composition. The desired solvent content depends, for example, on the desired thickness of the coated photoresist layer and the coating conditions.

[0047] The composition is first prepared by mixing the matrix polymer, the surface leveling agent, and any other solid components and optional additives together with a solvent. The composition can be subjected to additional processes such as filtration, ion exchange, etc., before being used. The composition can be applied to the substrate by spin coating, dipping, roller coating, or other coating methods. The substrate can include electronic device substrates, metal, wood, paper, polymer substrates, or base layers. The solids content of the coating solution can be varied to provide films of variable thickness. The solids content can also be based on the specific coating equipment utilized, the viscosity of the solution, the speed of the coating tool, and the amount of time used for rotation. In an embodiment, a layer of the composition can be applied in a single application. In another embodiment, a layer of the composition can be applied in multiple applications.

[0048] Depending on the particular coating composition, it may be beneficial to soft bake the layer of the composition (disposed on the substrate) to minimize the solvent content in the film. The soft bake promotes the formation of a tack-free coating and improves the adhesion of the composition layer to the substrate. The soft bake can be performed on a hot plate or in an oven, or alternatively, using ultraviolet light or using a laser.

[0049] In the case of a photoresist composition, the layer can then be patternwise exposed by direct writing or contact or by a pattern created using optical interference to allow irradiation through a photomask to create a solubility difference between exposed and unexposed areas. This irradiation creates a latent image in the layer. The photomask has optically transparent and optically opaque areas corresponding to areas of the layer of composition that are exposed or not exposed by activating radiation.

[0050] The layer of the composition can be optionally subjected to a post-exposure bake process, which is then developed to provide a resist relief image. In an embodiment, an alkaline developer is used to remove the exposed portion of the layer of the composition. Examples of alkaline developers include aqueous solutions of tetramethylammonium hydroxide, sodium hydroxide, and potassium hydroxide. The exposed portion can form a pattern, such as a hole (e.g., contact, via, or bump pattern) or a groove (e.g., line-space) pattern.

[0051] In one embodiment, the surface leveling agent is advantageous because it is miscible with water and wet developers. In another embodiment, the surface leveling agent exhibits a suitable level of hydrophobicity, which makes it miscible with organic solvent developers, rather than being miscible with water and wet developers. It does not contain fluorine, and is therefore environmentally friendly.

[0052] Surface leveling agents can be used as wetting agents to improve flow control. These properties (surface leveling and wetting ability) provide coatings with good optical properties (e.g., high gloss and good clarity of image). Thus, surface leveling agents can be blended with a wide variety of solutions, waxes, polishes, coatings, blends, etc. In embodiments, surface leveling agents can be used in floor polish formulations, paints, powder coating compositions, etc.

[0053] The invention will now be illustrated by the following non-limiting examples. EXAMPLES

[0054] Example 1 This hypothetical example is performed to demonstrate the synthesis of a monomer repeat unit used in a copolymer (surface leveling agent). The copolymer is made using 3-butyloxymethyl-3-methyloxetane as one of the monomers, tetrahydrofuran, and another monomer. In other words, 3-butyloxymethyl-3-methyloxetane is used to make the first polymer unit of the copolymer, and tetrahydrofuran is used to make the second polymer unit of the copolymer. The synthesis of the 3-butyloxymethyl-3-methyloxetane monomer is performed as follows: [ka]

[0055] A 50 weight percent (2.8 grams, 58.3 mmol) dispersion of sodium hydride in mineral oil is washed twice with hexane and suspended in 35 milliliters of dimethylformamide. Next, 3.9 grams (52.6 mmol) of butanol is added to the dispersion and the mixture is stirred for 45 minutes. A solution of 10.0 grams (39 mmol) of 3-hydroxymethyl-3-methyloxetane p-toluenesulfonate in 15 milliliters of dimethylformamide is added and the mixture is heated at 80° C. for 20 hours, at which time 'H-NMR analysis of an aliquot sample indicates that the starting sulfonate is completely consumed.

[0056] The mixture is then poured into 100 milliliters of ice water and extracted with two volumes of methylene chloride. The combined organic extracts are washed twice with water, twice with 2 weight percent aqueous hydrochloric acid, twice with brine, dried over magnesium sulfate, and evaporated to yield 3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane as an oil containing less than 1 weight percent dimethylformamide. The oil is distilled under reduced pressure to yield high purity 3-butyloxymethyl-3-methyloxetane monomer by analysis.

[0057] The synthesis of (3-methyloxetan-3-yl)methyl 3,3-dimethylbutanoate monomer is carried out as follows. [ka] In a 100 mL 4-neck flask, 10.0 g of 3,3-dimethylbutanoic anhydride (46.7 mmol), 0.6 g of dimethylaminopyridine (4.7 mmol) are dissolved in 250 ml of dichloromethane. 6.0 g of 3-ethyl-3-hydroxymethyloxetane (51.4 mmol) is added slowly in an ice-water bath and the reaction is allowed to stir at room temperature for 24 hours. The reaction mixture is then washed with saturated aqueous sodium bicarbonate, water and brine, then dried over magnesium sulfate overnight. The solvent is removed and the oil is distilled under reduced pressure to yield analytically pure (3-ethyloxetan-3-yl)methyl 3,3-dimethylbutanoate.

[0058] Example 2 This hypothetical example is conducted to demonstrate the synthesis of a polymer for use as a surface leveling agent. A method for preparing a copolymer using functional oxetanes and tetrahydrofuran is described in detail below.

[0059] A 400 ml flask (fitted with a condenser, thermocouple temperature probe, and mechanical stirrer) is charged with anhydrous methylene chloride (100 ml) and 1,4-butanediol (2.03 g, 22.6 mmol). Next, BF3THF (29.6 g, 211.7 mol), 2,2-dimethyl-1,3-propanediol (22.1 g, 211.7 mmol) are added and the mixture is stirred for 10 minutes. Next, a solution of 3-butyloxymethyl-3-methyloxetane (67 g, 423.4 mol) in anhydrous methylene chloride (30 ml) is pumped into the vessel over a period of 5 hours. The reaction temperature is maintained between 38-42°C throughout the addition. The mixture is then refluxed (with simultaneous stirring) for an additional 2 hours, after which it is cooled to 50°C. 1 H-NMR showed >98% conversion. The reaction was quenched with 10% aqueous sodium bicarbonate (200 mL) and the organic phase was washed with 3% aqueous HCl (200 mL) and water (200 mL). The organic phase was dried over sodium sulfate, filtered and stripped of solvent under reduced pressure to give the (3-methyloxetan-3-yl)methyl 3,3-dimethylbutanoate monomer as a clear oil.

[0060] Example 3 This hypothetical example is conducted to determine the resist coating and developing properties of the resist compositions. Formulations R1-R4 (resist compositions) and CR1-CR2 (comparative resist compositions) are prepared with the components and amounts shown in Table 1. In Table 1, the numbers in parentheses indicate the weight ratio of each component. The structures represented as C1-2, D1-2, and S1-2 are shown below in Table 2. Note that all polymers in Table 1 are prepared according to this general synthesis protocol. [ka]

[0061] [Table 1]

[0062] [Table 2]

[0063] The structures of the additives (C1, C2, D1 and D2) and solvents (S1 and S2) are shown immediately below. [ka]

[0064] Polymers A1 and A2 have a weight average molecular weight of 8000 g / mol. E1 is a polymer as described in Synthesis Example 2.

[0065] E2 is PolyFox PF-656, which is a commercial material manufactured by Omnova Solution Incorporation. [ka]

[0066] Each formulation is prepared using the components shown in Table 2, mixed together (by stirring) overnight, then passed through a 0.2 micrometer filter, spin-coated onto a wafer, and then exposed to a 65 nm / 130 nm pitch line / space pattern under an ASML1100 scanner with increasing focus with increasing dose, followed by a post-exposure bake (PEB) for 60 seconds at 100° C. After the PEB, the wafer is developed in 0.26 N TMAH wet developer for 12 seconds, rinsed with distilled water, and spun dry.

[0067] Coating defect evaluation is performed on the spin-coated wafers of the above compositions. After the compositions are spin-coated on hexamethyldisilazane (HDMS) primed silicon wafers, measurements are performed on a Hitachi CG4000 CD-SEM and SP2 tool evaluation. The total number of defects and haze value are measured for comparison.

[0068] To evaluate patterning defects, immersion lithography was performed using a TEL Lithius 300 mm wafer track and an ASML 1900i immersion scanner with dipole illumination at 1.3 NA (numerical aperture), 0.86 / 0.61 internal / external sigma, and 35Y polarization. Wafers for photolithography testing were coated with 800 Å AR40A bottom antireflective coating (BARC) and cured at 205°C for 60 seconds. Over the AR40A layer, 400 Å AR104 BARC was coated using a 175°C / 60 second cure. Over the BARC stack, 900 Å photoresist was coated using a 90°C / 60 second soft bake. Wafers were exposed to a 55 nm / 110 nm pitch line / space pattern at increased focus and dose, then post-exposure baked (PEB) at 100°C / 60 seconds. Following PEB, the wafers were developed with 0.26N TMAH wet developer for 12 seconds, rinsed with distilled water, and spun dry. Measurements were then performed on a Hitachi CG4000 CD-SEM, and the defect counts were calculated for comparison.

[0069] It is expected that the surface leveling agents described in this invention can be advantageously used to produce photoresist compositions that are free of numerous coating and patterning defects.

Claims

1. Formula (1): 【Chemistry 1】 [In the formula, R １ is H or a substituted or unsubstituted C １ ~C ６ is an alkyl group, and R ２ is -O-, -S-, -N-, -C(O)-, or -C(O)O-, -N-C(O)-, -C(O)-NR- (R is H or a substituted or unsubstituted C １ ~C ６ Optionally, one or more of the substituted or unsubstituted C ３ ~C ２０ a first polymerized unit of Formula (2): 【Chemistry 2】 [In the formula, R ３ is a substituted or unsubstituted C optionally containing one or more of -O-, -N-, -S-, -C(O)-, or -C(O)O-; １ ~C ６ and a second polymerized unit of the first polymerized units and the second polymerized units are chemically distinct; A fluorine-free copolymer, wherein the first polymerized unit of formula (1) is present in the copolymer in an amount greater than 60 mole %, based on the total number of moles in the copolymer.

2. R ２ The copolymer of claim 1 , wherein

3. Formula (3): 【Chemistry 3】 [In the formula, R ４ is -O-, -S-, -N-, -C(O)-, -C(O)O-, -N-C(O)-, or -C(O)-NR- (R is H or a substituted or unsubstituted C １ ~C ６ 2. The copolymer of claim 1, further comprising a third polymerized unit of:

4. The copolymer according to claim 3, wherein the first polymerized unit is represented by formula (1-1) and the second polymerized unit is represented by formula (2-1), and further wherein the copolymer is represented by formula (4): 【Chemistry 4】 (In the formula, R ４ is a substituted or unsubstituted C optionally containing one or more of -O-, -S-, -N-, -C(O)-, or -C(O)O-; ３ ~C ２０ is an alkyl group) 【Chemistry 5】 The copolymer further comprises a third polymerized unit of:

5. A composition comprising the copolymer according to any one of claims 1 to 4 and a solvent.

6. A composition comprising the copolymer of any one of claims 1 to 5 and a matrix polymer.

7. The composition of claim 6 further comprising a photoacid generator, wherein the matrix polymer comprises acid-decomposable groups.

8. The composition of claim 6 further comprising a thermal acid generator.

9. The composition of claim 6 further comprising a crosslinker.

10. A method of coating comprising applying a layer of the composition according to any one of claims 5 to 9 onto a substrate.

11. disposing a layer of the composition of any one of claims 5 to 7 on a substrate; exposing a layer of the composition to activating radiation; and developing the layer of said composition to provide a resist relief image.

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