TWI821199B - Multiple trigger monomer containing photoresist compositions and method - Google Patents

Abstract

The present disclosure relates to novel multiple trigger monomer containing negative working photoresist compositions and processes. The processes involve removing acid-labile protecting groups from crosslinking functionalities in a first step and crosslinking the crosslinking functionality with an acid sensitive crosslinker in a second step. The incorporation of a multiple trigger pathway in the resist catalytic chain increases the chemical gradient in areas receiving a low dose of irradiation, effectively acting as a built in dose depend quencher-analog and thus enhancing chemical gradient and thus resolution, resolution blur and exposure latitude. The photoresist compositions utilize novel monomers and mixtures of novel monomers. The methods are ideal for fine pattern processing using, for example, ultraviolet radiation, beyond extreme ultraviolet radiation, extreme ultraviolet radiation, X-rays and charged particle rays.

Description

Photoresist compositions and methods containing multiple triggering monomers

The present invention relates to novel negative photoresist compositions and methods of using them. The present invention further relates to a multi-trigger photoresist process that allows for improved contrast, resolution and/or line edge roughness in some systems without sacrificing sensitivity. Compositions comprising polymers, oligomers, resins and monomers containing cross-linking functional groups protected with acid-labile protecting groups, wherein the acid generated by photoacid removes the protecting groups to provide currently active cross-links Functional group. In a second step, the cross-linking functional groups react with the cross-linking agent in the presence of a photogenerated acid. In particular, novel monomers are used in the compositions. The photoresist compositions and methods of the present disclosure are ideal for fine pattern processing using, for example, ultraviolet radiation, extreme ultraviolet radiation, ultra-extreme ultraviolet radiation, X-rays, and charged particle beam exposure.

As is well known in the industry, the manufacturing process of various electronic or semiconductor devices such as ICs, LSIs, etc. involves fine patterning of a photoresist layer on the surface of a substrate material such as a semiconductor silicon wafer. This fine patterning process is traditionally performed through photolithography, in which the surface of the substrate is uniformly coated with a positive or negative tone photoresist composition to form a thin layer of the photoresist composition and is selectively illuminated with actinic rays (such as ultraviolet light) is irradiated through the photomask, followed by a development process to selectively dissolve the photoresist layer in areas exposed or not exposed to actinic rays, leaving a patterned photoresist layer on the surface of the substrate . The patterned photoresist layer thus obtained is used as a photomask in subsequent processing on the substrate surface. Such as etching, electroplating, chemical vapor deposition, etc. The fabrication of structures with nanometer-scale dimensions is an area of considerable interest, as it enables electronic and optical devices that exploit novel phenomena such as exploiting quantum confinement effects and allows for greater component packaging densities. Therefore, photoresist layers are required to have ever-increasing finesse. One method that can be used to achieve this is to use actinic rays with shorter wavelengths than traditional UV light, such as electron beams (e-beams), excimer laser beams, EUV, BEUV and X-rays, which are used as short-wavelength actinic rays ray. Needless to say, the minimum achievable size depends primarily on the properties of the photoresist material and the wavelength of the actinic rays. Various materials have been proposed as suitable photoresist materials.

Many positive photoresists typically apply a technique called "chemical amplification" to polymer photoresist materials. Chemically amplified photoresists are typically multi-component formulations in which there is a major polymeric component, such as a novolac resin, which contributes to properties such as the material's resistance to etch, mechanical stability, and developability; and one or A variety of additional components and photoacid generators that impart desired properties to photoresists. Usually, part of the hydroxyl groups of the phenolic polymer (such as novolac, polyhydroxystyrene, etc.) is protected by the functional group that reacts with the acid, and is removed to deprotect the hydroxyl group, making the hydroxyl group available for other reactions. It is developable in positive photoresist. By definition, chemical amplification occurs through a catalytic process involving a sensitizer, which results in a single radiation event causing a cascade effect by reacting with multiple functional groups of the protected novolac molecule. In a typical example, the photoresist contains a polymer and a photoacid generator (PAG) as a sensitizer. PAG releases protons in the presence of actinic radiation (light or electron beam). The protons then react with the polymer, causing it to lose its functional group, thus deprotecting the hydroxyl group. A second proton is produced in the process, which can then react with another molecule.

Many negative photoresists rely on photoacid generation to cause cross-linking or polymerization of the photoresist components, making the exposed area insoluble in the developer, which is solvent or water-based, especially aqueous alkaline developers. these lights The resist process often requires a heating step to efficiently and effectively cause the reaction (polymerization or cross-linking) because there is not enough polymerization or cross-linking at room temperature to render the resist impervious to developer penetration. Most of these negative photoresists also require post-bake to further cure the remaining photoresist pattern.

Negative photoresists are also described, which combine chemically amplified positive photoresist chemicals with negative curing agents (eg, cross-linkers). In these photoresists, a phenolic polymer whose hydroxyl groups are partially protected is combined with a cross-linker and a photoacid generator. During exposure, the protected hydroxyl groups are deprotected and free to react with cross-linking groups, see for example Hakey, US Patent No. 6,114,082. In this disclosure, the phenolic polymer needs to be partially protected (75% protected) so that after exposure, the aqueous alkaline developer can dissolve the unexposed areas, allowing the negative image to remain. It is also disclosed that post-exposure heating is required to allow the photoresist to be properly cured to prevent the developer from attacking the exposed areas of the photoresist. The rate of the curing reaction can be controlled, for example, by heating the photoresist film after exposure (post exposure bake (PEB)) to drive reactions that cause loss of functional groups and/or cross-linking/curing. Also during the heating process, the reacted polymer molecules are free to react with the rest of the formulation, which is true for negative photoresists. As mentioned above, these systems require heating of the photoresist to accomplish the required cross-linking, rendering the exposed areas insoluble in the developer.

A well-known and documented problem with chemically amplified photoresists is a phenomenon called "resist blur" or "dark reaction." During this process, photo-generated acid migrates from exposed areas (acid migration) and into unexposed areas, where it may cause undesirable reactions. In positive photoresists, a line sharpening result is produced, whereas in negative photoresists, a line broadening result is produced. Various methods and photoresist compositions have been introduced to control acid diffusion, such as the addition of base quenchers, which react with the diffusing acid to remove it from the system before any unwanted photoresist reaction. The addition of alkali quenchers inherently brings limitations such as reduced sensitivity, development issues, etc. Additionally, since most photoresists require PEB, Increased temperature imparts higher kinetic energy to the system, so the acid causes an increase in the degree of migration and therefore line broadening. In some cases where a small critical dimension (CD) is required, the exposure latitude of these systems is severely reduced, including line bridging and poor resolution.

As can be seen, there is an ongoing desire to obtain increasingly finer photoresist resolutions, which will allow the fabrication of smaller and smaller semiconductor devices to meet current and further demands. To achieve these lofty goals, line broadening and line edge roughness need to be reduced, and exposure latitude and contrast need to be improved. Accordingly, it would be desirable to create materials, compositions, and methods that can be used in conjunction with these photoresist processes to produce these improvements.

This application claims priority from U.S. Patent Application No. 15/687449, entitled "Multiple Trigger Photoresist Compositions and Methods", filed on February 24, 2017, which application is incorporated herein by reference in its entirety.

In a first embodiment, a multi-trigger negative photoresist composition is disclosed, which includes: (a) at least one polymer, oligomer, resin or monomer, each of which includes two or more cross-linkable Functional groups, wherein substantially all of the functional groups are linked to acid-labile protecting groups; (b) at least one acid-activated cross-linking agent; and (c) at least one photoacid generator.

In a second embodiment, the multi-trigger negative photoresist composition of the above embodiment is disclosed, wherein the monomer is one or more of the following structures (I), (II), (III) and (IV) A compound _, wherein R ₂ , R ₃ and R ₄ are the same or different, and are branched or unbranched, substituted or unsubstituted, saturated or unsaturated monovalent alkyl chains with 1 to 16 carbon atoms, which may or may not have one or multiple heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, heteroaromatic groups, fused aromatic or fused heteroaromatic groups, aralkyl groups, alicyclic groups group, or a cyclic, bicyclic or polycyclic ring formed when any 2 or more of R ₁ , R ₂ , R ₃ and R ₄ are covalently linked to each other.

In a third embodiment, the multi-trigger negative photoresist composition of any of the above embodiments is disclosed, wherein at least one of X or Y includes: -(alkyl) _j -(aryl) _k -(O) _p -(COO) _q -ALPG where the values of j, k, p, q are as follows:

wherein alkyl is a branched or unbranched, substituted or unsubstituted, saturated or unsaturated divalent alkyl chain having 1 to 16 carbon atoms, with or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted aromatic group, heteroaromatic group or fused aromatic or fused heteroaromatic group, and ALPG is an acid-labile protecting group, and ALPG contains a leaving group , and can be a tertiary alkyl group, an alicyclic group, a ketal or a cyclic aliphatic ketal, or an acetal.

In a fourth embodiment, the multi-trigger negative photoresist composition of any of the above embodiments is disclosed, further comprising at least one photoacid generator, and the at least one photoacid generator includes an onium salt compound, a sulfonium salt, Phenyl sulfonium salt, sulfonyl imine, halogen-containing compound, sulfonate, sulfonyl imine, sulfonate ester, quinonediazide, diazomethane, quinone salt, oxime sulfonate, dicarboxyliminosulfate , imidelaminooxysulfonates, sulfonyldiazomethane, or mixtures thereof, capable of generating acids when exposed to at least one of UV, deep UV, extreme UV, X-ray or electron beam actinic radiation. The at least one acid-activated cross-linking agent includes aliphatic, aromatic or aralkyl monomers, oligomers, resins or polymers, including glycidyl ethers, glycidyl esters, oxetanes, glycidyl amines, Methoxymethyl group, ethoxymethyl group, butoxymethyl group, benzyloxymethyl group, dimethylaminomethyl group, diethylaminomethylamine group, dioxane methylamine group, dibutoxymethylamine group, dihydroxymethylmethylamine group, dihydroxyethylmethylamine group, dihydroxybutylmethylamine group, morpholinemethyl group , at least one of an acetyloxymethyl group, a benzyloxymethyl group, a formyl group, an acetyl group, a vinyl group or an isopropylene group and a solvent, wherein the solvent includes ester, ether, Ether-esters, hydroxyesters, hydroxyethers, ketones, ketone-esters, hydrocarbons, aromatic compounds, halogenated solvents, alkyl-aryl ethers or combinations thereof.

In a fifth embodiment, a multi-trigger negative photoresist composition according to any of the above embodiments is disclosed, wherein when exposed to a photoacid-generated acid and optionally during a post-exposure bake process, the acid-labile protection The group can be removed, providing functional groups capable of cross-linking with the cross-linking agent when the cross-linking agent is exposed to the photoacid.

In a sixth embodiment, the multi-trigger negative photoresist composition of any of the above embodiments is disclosed, wherein the monomer has the following structure (V), (VI), (VII) or (VIII) one or more of.

In a seventh embodiment, a method for forming a patterned photoresist layer on a substrate is disclosed, including the following steps: (a) providing a substrate; (b) applying the multi-trigger negative photoresist combination of any one of the above embodiments (c) heating the coated substrate to form a substantially dry coating to obtain the desired thickness; (d) imagewise exposing the coated substrate to a light selected from UV, deep UV, extreme UV, X-ray or Actinic radiation of one or more of electron beam actinic radiation; and (e) removing unexposed areas of the coating using an aqueous solvent, an organic solvent, or a combined aqueous-solvent developer composition; leaving a photoimageable pattern therein Optionally heated.

In a seventh embodiment, a method for forming a patterned photoresist layer on a substrate according to the above embodiment is disclosed, wherein under environmental conditions that provide functional groups that can cross-link with the cross-linking system when the cross-linking system is catalyzed by an acid. Acid-labile protecting groups can be removed upon exposure to acid, where the acid-labile protecting groups include tertiary alkoxycarbonyl groups.

In an eighth embodiment, the method of forming a patterned photoresist layer on a substrate according to the above embodiment is disclosed, wherein the at least one photoacid generator includes an onium salt compound, triphenylsulfonium salt, sulfonimide, halogen-containing compound, sulfonate, quinonediazide, diazomethane, iodine salt, oxime sulfonate or dicarboxylimide sulfate, wherein the at least one acid-activated cross-linking agent includes a monomer, a resin, an oligosaccharide Polymer or polymer, which includes glycidyl ether, glycidyl ester, glycidyl amine, methoxymethyl group, ethoxymethyl group, butoxymethyl group, benzyloxymethyl group, dimethyl Aminomethyl group, diethylaminomethylamine group, dialkylmethylamine group, dibutoxymethylamine group, dimethylolmethylamine group, dihydroxyethyl Methylamine group, dihydroxybutylmethylamine group, morpholine methyl group, acetyloxymethyl group, benzyloxymethyl group, formyl group, acetyl group, vinyl group, At least one of an isopropylene group or one or more glycidyl ether groups attached to an aromatic monomer, oligomer or polymer.

In a ninth embodiment, the method of forming a patterned photoresist layer on a substrate according to the above embodiment is disclosed, wherein the multi-trigger negative photoresist composition includes a monomer, and the monomer has the following structure (V), One or more of (VI), (VII) or (VIII).

In another embodiment, compositions and methods of the above embodiments are disclosed that include mixtures of monomers having structures I to VIII as described below.

[FIG. 1] shows scanning electron micrographs of etched features produced using Composition Example 3 (FIG. 1(A)) and Composition Example 4 (FIG. 1(B)) described below.

[FIG. 2] shows scanning electron micrographs of etched features produced using Composition Example 5 (FIG. 2(A)) and Composition Example 6 (FIG. 2(B)) described below.

[Figure 3] shows a scanning electron micrograph of etched features produced using Composition Example 7 described below.

As used herein, unless otherwise stated, the conjunction "and" is intended to be inclusive, and the conjunction "or" is not intended to be exclusive. For example, the phrase "or, alternatively" is intended to be exclusive.

As used herein, the terms "have," "contains," "includes," "includes," etc. are open-ended terms indicating the presence of stated elements or features but not excluding other elements or features. levy. The articles "a", "an" and "the" are intended to include the plural as well as the singular unless the context clearly indicates otherwise.

As used herein, the phrase "acid labile protecting group (ALPG)" refers to a cross-linking functionality attached to a cross-linkable functional group and having a cross-linking functionality that reacts with an acid causing its removal and thus its incorporation. A group with deprotecting properties, which cross-links the cross-linking functional group with the cross-linking agent in the second step. ALPG may include one or more moieties, including, for example, a leaving group (LG). In some cases, leaving an unstable intermediate, the leaving group of this intermediate further decomposes and "leaves", resulting in a cross-linking functional group that is now unprotected.

As used herein, the terms "dry", "dry" and "dry coated" mean having less than 8% residual solvent.

As used herein, the phrase "substantially all" means at least 90%.

The present disclosure describes a multi-trigger negative photoresist composition comprising: a) at least one polymer, oligomer or monomer, each of which includes two or more cross-linkable functional groups, wherein substantially all The functional groups are all connected to acid-labile protecting groups; b) at least one acid-activated cross-linking agent; and c) at least one photoacid generator. Surprisingly, it has been found that when virtually all crosslinkable functional groups of a polymer, oligomer, resin or monomer in combination with an acid-activated cross-linker are attached to an acid-labile protecting group, as described below Considered a multi-trigger negative photoresist process, it offers significant improvements in resolution, resolution blur, exposure latitude and adjustable sensitivity.

Cross-linkable functional groups for negative photoresists are well known in the industry and include, for example, hydroxyl groups, amine groups, oximes, and the like. In the presence of acids and acid-activated cross-linking agents, functional groups will react with them to cross-link. These functional groups can be linked to ballast groups, such as alkyl, aryl or aralkyl groups. Such aromatic groups useful in the present disclosure include, for example, substituted or unsubstituted divalent aromatic groups, such aromatic groups include, for example, phenylene (-C ₆ H ₄ -), fused divalent aromatic groups. Valent aromatic groups, such as naphthylene (-C ₁₀ H ₆ -), anthracene (-C ₁₄ H ₈ -), etc.; and heteroaryl groups, such as nitrogen heterocycles: pyridine, quinoline, pyrrole, indole , pyrazole, triazine, and other nitrogen-containing aromatic heterocycles well known in the art; and oxygen heterocycles: furans, oxazoles, and other oxygen-containing aromatic heterocycles; and sulfur-containing aromatic heterocycles, such as thiophene. Trivalent and tetravalent aromatic compounds may also be used.

Such alkyl groups useful in the present disclosure include branched or unbranched, substituted or unsubstituted, saturated or unsaturated divalent alkyl chains having 1 to 16 carbon atoms, with 0 to 16 heteroatoms substituted into the chain middle.

The aromatic groups may be in the form of oligomers, polymers or resins or monomers with a molecular weight between about 100 Daltons and 100,000 Daltons and are highly dependent on the desired properties of the cured negative photoresist pattern, e.g. Etching resistance.

Examples of polymers or oligomers include phenol-based novolacs, cresols, resorcinols, pyrogallol, and the like, including copolymers prepared therefrom. Additionally, polyhydroxystyrene-based polymers and derivatives or copolymers thereof may be used in these photoresist compositions.

Acid-labile protecting groups block or protect cross-linkable functional groups. Acid labile protecting groups include, for example, substituted methyl groups, silane groups, germane groups, and alkoxycarbonylic acid labile protecting groups include, for example, methoxycarbonyl groups, ethoxycarbonyl groups, Isopropoxycarbonyl and tert-butoxycarbonyl groups, carboxylate groups, sulfur-based ester groups, vinyl groups, ketals, acetals, etc. include, for example, tert-butyl groups, tert-amyl groups, 2 ,3-dimethylbutan-2-group, 2,3,3-trimethylbutan-2-group, 2,3-dimethylpentan-3-group, 2-methylbicyclo[2.2 .1]hept-2-group, bicyclo[2.2.1]hept-2-group, 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1 - an ethylcyclohexyl group, a 2-methyladamantane group or a 2-ethyladamantane group.

Acid-activated cross-linkers suitable for use in the present disclosure constitute compounds capable of cross-linking with the cross-linkable functional groups described above during processing such that when deprotected to provide, for example, phenol or similar groups, the cross-linker will interact with the currently deprotected -OH or similar groups located on phenol or similar groups react. Cross-linking agents can be polymers, oligomers, resins or monomers. Without being bound by theory, it is believed that the acid generated by exposure to actinic radiation not only reacts with acid-labile protecting groups of polymers, oligomers, resins, or monomers to act as a first trigger, but also contributes to The reaction between the crosslinking agent and the crosslinkable functional group serves as the second trigger for the curing reaction. This curing reaction reduces the solubility of the developer in the exposed and currently reacting areas, thereby creating a pattern of cured material. Examples of cross-linking agents include compounds containing at least one substituent group having cross-linking reactivity with a hydroxyl group, such as from phenols, amines or similar groups from polymers, oligomers, resins or monomers group.

Specific examples of acid-activated cross-linking agents include glycidyl ether groups, glycidyl ester groups, glycidyl amine groups, methoxymethyl groups, ethoxymethyl groups, benzyloxymethyl groups, dimethyl hydroxylaminomethyl group, diethylamine methyl group, dihydroxymethylmethylamine group, dihydroxyethylmethylamine group, morpholine methyl group, acetyloxymethyl group, Benzyloxymethyl group, formyl group, acetyl group, vinyl group and isopropylene group.

Photo acid generators (PAGs) suitable for the multi-trigger negative photoresist of the present disclosure include onium salt compounds, tertiary imine compounds, halogen-containing compounds, terine compounds, ester sulfonate compounds, and quinone peroxide compounds. Nitrogen compounds and diazomethane compounds.

Compositions of the present disclosure may include one or more photoacid generators described above.

Examples of solvents suitable for use in the present disclosure include ethers, esters, alcohols, ether esters, ketones, lactones, ketoesters, and the like.

Various additives can be added to the photoresist composition to provide certain desired properties of the photoresist, such as acid diffusion control agents to prevent acid migration into unexposed areas of the coating, surfactants to improve substrate coatings, adhesion Accelerators are added to improve the adhesion of the coating to the substrate, sensitizers are added to improve the photosensitivity of the photoresist coating during exposure, as well as defoamers and air release agents and other materials well known in the coatings industry.

The cross-linkable functional groups are all blocked by acid-labile protecting groups, from about 90% to about 100%. Acid labile groups have the well-known property of being able to be removed when exposed to acid and optionally heat.

The compositions of the present disclosure include, on a weight/weight basis, a composition ranging from about 1% to about 65% of protected polymer, oligomer, resin or monomer and about 10% of acid-activated crosslinker. to about 80%, and the photoacid generator is from about 0.5% to about 50%. The composition may have a solids percentage of about 0.001% to about 25%.

Surprisingly, it has been found that specific monomers can be formulated into the presently disclosed multi-trigger negative photoresist compositions with excellent results. These monomers include esters, where esters are the product of a chemical reaction between malonate and amidine in the presence of a suitable halogen donor or pseudohalogen donor:

_{wherein _ _ 4} is the same or different, and is a branched or unbranched, substituted or unsubstituted, saturated or unsaturated divalent alkyl chain with 1 to 16 carbon atoms, which may or may not have one or more heteroatoms substituted into the chain, a substituted or unsubstituted aromatic group, a heteroaromatic group, a fused aromatic or fused heteroaromatic group, an aralkyl group, an alicyclic group, or when R ₁ , A cyclic, bicyclic or polycyclic ring formed when any 2 or more of R ₂ , R ₃ and R ₄ are covalently linked to each other, and may be fused as follows:

Among them, m=1~4, n=1~4.

A multi-trigger negative photoresist composition is disclosed here, including: at least one monomer ester having a general structure selected from (I), (II), (III) or (IV); at least one photoacid generator; at least one cross-linking agent; and at least one solvent; wherein Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same or different, and are branched or unbranched, substituted or unsubstituted, saturated or unsaturated monovalent alkyl chains with 1 to 16 carbon atoms, which have or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, heteroaromatic groups, fused aromatic or fused heteroaromatic groups, aralkyl groups, Alicyclic groups, or cyclic, bicyclic or polycyclic rings formed when any 2 or more of R ₁ , R ₂ , R ₃ and R ₄ are covalently linked to each other, and may Condensation.

In the above, the group -N=R ₃ ' is used here to represent an amine in which the R ₃ group is linked by a double bond.

Further disclosed herein is a multi-trigger negative photoresist composition comprising at least one monomer ester having a structure selected from (V), (VI), (VII) or (VIII), wherein X and Y include acid-labile group, and where m=1~4, n=1~4.

In the structures I-VIII disclosed above, at least one of X or Y may contain an acid-labile protecting group, such that X or Y has the general structure -EO _p -COO-LG

It may or may not contain the extended chain -E-. Furthermore, the acid-labile protecting group may comprise a carbonate (where p=1) or a carboxylate (where p=0) and a leaving group LG. In the case of carbonates, the ALPG group is a combination of LG and _CO , both of which are eliminated during the deprotection reaction, leaving the OH group. In the case of carboxylate esters, ALPG is only the ester moiety that is eliminated, leaving the carboxylic acid. In some cases, carboxylic acids can be removed through decarboxylation using a base. As an example, either or both X and Y may include structures such as -alkyl-aryl-(O) _p -COO-LG

where p=0 or 1, where the -alkyl-aryl- part is an extended chain, where alkyl is a branched or unbranched, substituted or unsubstituted, saturated or unsaturated divalent alkyl chain with 1 to 16 carbon atoms, With or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted divalent phenyl group, a divalent heteroaromatic group or a divalent fused aromatic or fused heteroaromatic group group, where -O-COO-LG is acid labile A defined protecting group that is removed when reacting with a photogenerated acid. In addition to the carbonates described above, ALPG may contain acid-labile carboxylic esters with similar leaving groups. ALPG can be a tert-butoxy carbonate group, a tert-butoxy carboxylate group, or other carbonate or carboxylate groups with leaving groups, such as but not limited to tert-alkyl or cycloalkyl groups, lipid Cyclic groups, ketals or cyclic aliphatic ketals or acetals. Additionally, ALPG may include a mass persistent moiety, where p=0 and the leaving group is bonded to the extending chain.

Non-limiting examples may generally be represented by structures, and may include, for example, the following structures:

The substances in brackets above show a putative acidolysis reaction, where the point of attachment to the remainder of group E is shown. Wherein R ₆ is hydrogen, methyl, ethyl or benzyl, R ₇ and R ₈ can be the same or different, and can be methyl, ethyl or benzyl, q=0 to 4. Numerous examples of durable photoresists are known. See, for example, Klop et al., Chem. Commun., (2002), 2956-2957, and Ushirogouchi et al., Proc. SPIE, 3999, 1147, (2000).

Additionally, X and Y may have no extended chains or include, for example, but not limited to, bivalent extended chains including -alkyl-, -aryl-, -alkyl-aryl-, -aryl-alkyl-, -alkoxy- , -alkoxy-aryl-, -aryl-alkoxy-, -alkyl-alkoxy-, -alkoxy-alkyl- or a combination of the foregoing, where alkyl is branched or unbranched, substituted or unsubstituted, with 1 to 16 carbon atoms, A saturated or unsaturated divalent alkyl chain with or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted aromatic group, heteroaromatic group or fused aromatic group or fused heteroaromatic groups, and where ALPG is an acid-labile protecting group.

The above-mentioned -aryl- is a substituted or unsubstituted divalent aromatic group. These aromatic groups include: for example, phenylene (-C ₆ H ₄ -); condensed divalent aromatic group, such as naphthylene. group (-C ₁₀ H ₆ -), anthracene group (-C ₁₄ H ₈ -), etc.; and heteroaromatic groups, such as nitrogen heterocyclic compounds: pyridine, quinoline, pyrrole, indole, pyrazole, tris Azines and other nitrogen-containing aromatic heterocycles well known in the art; and oxygen heterocycles: furans, oxazoles, and other oxygen-containing aromatic heterocycles; and sulfur-containing aromatic heterocycles, such as thiophenes.

Turning to the leaving group LG, on one of X or Y, LG can be H or D as long as the other of X or Y includes ALPG. ALPG is intended to be a group that is removable or acidolytically removable, and may include, for example, but not limited to, a tertiary alkyl leaving group having the general structure -CR ₅ R ₆ R ₇ , where R ₅ , R ₆ and R ₇ may be the same or different, and represent linear or branched alkyl, heteroalkyl or alkylaryl. Without limitation, exemplary groups may be tert-butyl group, tert-amyl group, 2,3-dimethylbut-2-group, 2,3,3-trimethylbut-2-group , 2,3-dimethylpentan-3-group, 2-methylbicyclo[2.2.1]hept-2-group, bicyclo[2.2.1]hept-2-group, 1-methylcyclo Pentyl group, 1-ethylcyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 2-methyladamantane group or 2-ethyladamantane group. Additionally, exemplary tertiary carbon-containing leaving groups may include ring structures having oxygen atoms, such as mevalonolactone groups.

Acid labile protecting groups may also include, but are not limited to, substituted methyl, silyl, ketals, and acetals.

Alkoxycarbonyl leaving groups include methoxycarbonyl, ethoxycarbonyl, isopropoxycarbonyl and tert-butoxycarbonyl groups. Acid-labile groups include, for example, acetyl group, propionyl group, butyl group, heptyl group, hexyl group, valeryl group, neopentyl group, isopentyl group, lauryl group acyl group, myristyl group, palmityl group, stearyl group, oxalyl group, malonyl group, succinyl group, glutadiyl group, adipidyl group, piperonyl group Aridyl group, suberyl group, nonyl group, sebacyl group, acrylic group, propynyl group, methacryl group, crotonyl group, oleyl group, horse Lysyl group, fumaryl group, zhongkang group, camphor group, benzyl group, phthalyl group, isophthalyl group, terephthalyl group, naphthyl group group, toluyl group, hydrogenated urea group, nonyl group, cinnamyl group, furanyl group, thiophene group, nicotinyl group, isonicotinyl group, p-toluenesulfonyl group and methanesulfonyl group.

The leaving group may also include cyclic or alicyclic structures that can be removed by acidolysis, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexene group, a 4-methoxycyclohexyl group, a tetrahydrofuran group, Hydropyran group, tetrahydrofuran group, tetrahydrothiopyran group, tetrahydrothiophene group, 3-bromotetrahydropyran group, 4-methoxytetrahydropyran group, 4-methoxy group Tetrahydrothiopyran group and 3-tetrahydrothiophene-1,1-dioxyl group.

The negative photoresist composition disclosed here contains the esters of (I) to (VIII) as described above, or, in the presence of a suitable halogen donor or pseudo-halogen donor, the above-mentioned malonate ester reacts with the above-mentioned amidine any other product obtained; at least one crosslinkable material; and at least one acid generator, wherein the ester replaces at least a portion of the resin used in conventional negative photoresists.

The methods for preparing the above monomeric esters I~IV and V~VIII produce mixtures of I~IV and V~VIII respectively. The isolation of these synthetic esters is laborious and expensive because their structures are very similar and play similar roles in the isolation scheme. It was unexpectedly found that compositions disclosed directly using mixtures of esters gave results that were in some embodiments the same as or better than compositions using isolated purified esters. From a cost and yield perspective, this can result in significant cost savings, as more can be used from the synthesis reaction and less is lost in the isolation scheme. Furthermore, it was unexpectedly found that the presence of similar substances in the composition tends to inhibit nucleation, aggregation and/or crystallization, which contributes to line edge roughness and poor film quality. Generally speaking, it is more desirable to use "purified" compositions than mixtures containing materials commonly referred to as "by-products." However, in the examples of the present disclosure, the mixture was surprisingly superior.

The photoresist composition may be coated onto a substrate, such as a silicon wafer or wafer coated with silicon dioxide, aluminum, alumina, copper, nickel, any of a variety of semiconductor materials or nitrides, or other substrates well known in the semiconductor industry, Or a substrate having an organic film (such as an underlying anti-reflective film) or the like thereon. The photoresist composition is applied through processes such as spin coating, curtain coating, slot coating, dip coating, roller coating, blade coating, and the like. After coating, the solvent is removed to the extent that the coating can be properly exposed. In some cases, a remaining 5% solvent may remain in the coating, while in other cases, less than 1% is required. Drying can be accomplished through hot plate heating, convection heating, infrared heating, etc. The coating is image-exposed through markings containing the desired pattern.

Radiation suitable for use in the photoresist composition includes, for example, ultraviolet rays (UV), such as the bright line spectrum of a mercury lamp (254 nm), KrF excimer laser (248 nm) and ArF excimer laser (193 nm), extreme ultraviolet ( extreme ultraviolet (EUV), such as 13.5nm light from plasma discharges and synchrotron light sources, beyond extreme ultraviolet (BEUV), such as 6.7nm exposure, X-rays, such as synchrotron radiation. Ion beam lithography and charged particle rays such as electron beams can also be used.

After exposure, the exposed coated substrate may optionally undergo a post-exposure bake to enhance the reaction of the photoacid generator, for example, heating at about 30 to about 200° C. for about 10 to about 600 seconds. This can be achieved through hot plate heating, convection heating, infrared heating, etc. Heating can also be performed through a laser heating process, for example, CO ₂ laser pulse heating for about 2 to about 5 milliseconds. Both heating processes can be combined in series.

A flood exposure process may optionally be applied after pattern exposure to aid further curing. The results indicate that full-surface exposure reduces or eliminates pattern collapse and reduced line edge roughness after negative tone photoresist development. For example, a 532nm continuous wavelength laser exposes a previously exposed photoresist for 1 to 2 seconds, followed by wet development. The whole-surface exposure process may or may not be accompanied by a heating step.

Next use developer to move the unexposed areas. These developers typically include organic and semi-aqueous solvents. The developing solvent is less aggressive than the solvent used to prepare the photoresist composition.

After development, a final bake step can be included to further enhance the curing of the now exposed and developed pattern. The heating process can be, for example, about 30 to about 300° C., about 10 to about 120 seconds, and can be completed by hot plate heating, convection heating, infrared heating, etc.

While not to be construed as theory, it is believed that curing of the system involves multiple triggers and, in the example below, is a two-step process in which both the protected cross-linking functionality and the cross-linking agent must be exposed to the acid to allow They react. When PAG is exposed to actinic radiation, acids are produced that will cross-link functional groups Deprotected, the cross-linking functional group can now cross-link with the cross-linking agent only if the acid generated by radiation activates the cross-linking agent in the presence of the cross-linking functional group. Because two reactions are required, it is believed that "acid migration" or "dark reaction" is suppressed and photoresist blur is reduced, and resolution and exposure latitude are significantly improved. See option 1 below. Theoretically, if a third reaction is required to cure the negative photoresist, resolution blur, further improvements in resolution and exposure latitude will occur.

In Scheme 1, the protected cross-linkable functional group A is deprotected in the presence of the acid radical H ⁺ , and a deprotected compound B is produced, in which the functional group is -OH. The cross-linking agent C and the cross-linkable functional group can react together in the presence of acid to obtain the cured material D.

The following examples and the following discussion will demonstrate surprising improvements to the present disclosure.

Examples using monolithic materials

Synthesis of monomer A:

Step 1:

Add 3-(4-hydroxyphenyl)-1-propanol (102.1g, 670.9mmol), dichloromethane (760mL) and dichloromethane (760mL) into a 3L round-bottomed flask. Di-tert-butyldicarbonate (146.4g, 670.9mmol). The mixture was stirred under nitrogen and cooled to 0°C in an ice bath. Potassium carbonate (250.3g, 1811.3mmol) and 18-crown-6 (8.9g, 33.5mmol) were added. The resulting mixture was stirred and warmed to room temperature overnight. The crude reaction mixture was evaporated to remove most of the solvent and the residue was purified by flash column chromatography on silica gel using ethyl acetate:hexane (40%/60%) as eluant. The third fractions were combined together, and the solvent was removed to obtain 135.6 g (yield: 80%) of 1 as a yellow oil. The product was characterized by ¹ H NMR.

Step 2:

Dichloromethane (2L) was added to 1 (135.6g, 537.7mmol) in a 3L round bottom flask. Pyridine (56.6 g, 715.1 mmol) was added thereto with stirring and the solution was cooled to 0°C in an ice bath under nitrogen. Malonyl dichloride (34.8 mL, 357.6 mmol) was added dropwise using an addition funnel. Upon complete addition of malondichloride, the initially clear solution turned dark red. The mixture was stirred and allowed to warm to room temperature overnight, at which time it turned dark blue/green. The mixture was filtered through a silica plug, which was rinsed with ethyl acetate. The filtrate was evaporated and the residue was purified by silica gel flash column chromatography using 25% ethyl acetate/n-hexane as eluent. Fractions were collected and the solvent was removed to afford 2 as a yellow oil (93.1 g, 61% yield). The product was characterized by ¹ H NMR.

Step 3:

Tetrabromomethane (4.05g, 12.2mmol) and 2 (6.3g, 11.0mmol) were added to a 500mL round bottom flask. Toluene (240 mL) was added and the mixture was stirred under nitrogen for 1 hour. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU, 7.3 g, 48.2 mmol) was added dropwise. The reaction mixture was stirred under nitrogen for 18 hours, then filtered. The resulting mixture was purified through a silica column using toluene, then ethyl acetate, then a 20% to 50% gradient of isopropanol/ethyl acetate. The fifth fraction was collected and the solvent was removed to give the final product as a pale yellow solid (3.4 g). The product was characterized by ¹ H NMR and elemental analysis and by ¹³ C NMR analysis, which showed that it was most likely a mixture of combinations of monomers V~VIII, where m=2 and n=3.

Synthesis of monomer B:

The synthesis steps are similar to the monomers, except that 1,5-Diazabicyclo(4.3.0)non-5-ene (DBN, 5.95g, 48.2mmol) instead of DBU. The product was characterized by ¹ H NMR ¹³ C NMR, Moldi-TOF, crystallography and Mass Spec.

Composition Example 1:

Add 0.25g monomer A and 0.50g poly[(o-cresyl glycidyl ether)-co-formaldehyde] (poly[(o-cresyl glycidyl ether)- co-formaldehyde]) and 0.25g triphenylsulfonium hexafluoroantimonate. The mixture was stirred at room temperature for 1 hour and filtered through a 20 nm PTFE membrane filter available from Pall Corporation, Port Washington New York. The composition was applied to the silicon wafer and spin-coated at 500 rpm for 5 seconds, followed by Spin coating at 2000rpm for 60 seconds. The coated wafer was then heated on a hot plate at 75°C for 5 minutes to obtain a film of approximately 25 nm. The coated wafer was then imagewise exposed to synchrotron radiation based on EUV light with a wavelength of 13 to 14 nm and baked at 90°C for 3 minutes. Unexposed areas were removed by puddle development in a 50:50 mixture of monochlorobenzene and isopropyl alcohol for 20 seconds, followed by an isopropyl alcohol rinse.

Composition Example 2:

The composition and method of Composition Example 1 were used, except that Monomer B material was used.

Composition Example 3:

Add 0.05g monomer A product and 0.50g poly[(o-cresyl glycidyl ether)-co-formaldehyde]) (poly[(o-cresyl glycidyl ether)-co-formaldehyde]) ( Mn=1270) and 0.25g triphenylsulfonium hexafluoroantimonate, and stir at room temperature for 1 hour. The composition was applied to a silicon wafer and spin-coated at 500 rpm for 5 seconds, followed by 1500 rpm for 90 seconds. The coated wafer was then heated on a hot plate at 70°C for 5 minutes to obtain a film of approximately 25 nm. The wafers were imagewise exposed to an electron beam (E-beam) and post-exposure baked at 90°C for 1 minute. Unexposed areas were removed by melt pool development in cyclohexanone for 20 seconds and rinsed with isopropyl alcohol. A line dose of 142pC/cm was applied, giving dense lines of 40nm half pitch. Figure 1(A) shows the resulting print characteristics.

Composition Example 4:

Use poly[(o-cresyl glycidyl ether)-co-formaldehyde] (poly[(o-cresyl glycidyl ether)-co-formaldehyde]) (Mn=870) instead of poly[(o-cresyl glycidyl ether)-co-formaldehyde] -Formaldehyde] (poly[(o-cresyl glycidyl ether)-co-formaldehyde]) (Mn=1270), repeat Composition Example 3. A line dose of 107 pC/cm was applied, giving dense lines of 38 nm half pitch. Figure 1(B) shows the resulting print characteristics.

Composition Example 5:

Add 0.04g triphenylsulfonium nonaflate to the photoresist composition and repeat Composition Example 3. A line dose of 117 pC/cm was applied, giving dense lines of 38 nm half pitch. Figure 2(A) shows the resulting print characteristics.

Composition Example 6:

Add 0.008g of 1,8-Diazabicycloundedec-7-ene into the photoresist composition, and repeat Composition Example 5. A line dose of 156 pC/cm was applied, giving dense lines of 38 nm half pitch. Figure 2(B) shows the resulting print characteristics.

Composition Example 7:

Add 0.05g of monomer B product and 0.50g of poly[(o-cresyl glycidyl ether)-co-formaldehyde] to 67.2mL of ethyl lactate. ]) (Mn=870), 0.04g triphenylsulfonium trifluoromethane sulfonate and 0.25g triphenylsulfonium hexafluoroantimonate, and stir at room temperature for 1 hour . The composition was applied to a silicon wafer and spin-coated at 3000 rpm for 90 seconds. The coated wafer was then heated on a hot plate at 105°C for 5 minutes to obtain a film of approximately 25 nm. The wafer was imagewise exposed using EUV light with a wavelength of approximately 13.4 nm, masked at a dose of 88 mJ/cm ² (the estimated dose for the wafer is 8.8 mJ/cm ² ) and baked at 90°C for 3 minutes. Development through a bath in cyclohexanone for 30 seconds, followed by a rinse with isopropyl alcohol to remove unexposed areas, produced 14 nm half-pitch lines. Figure 3 shows the resulting print characteristics.

Although the present invention has been shown and described with reference to specific embodiments, it will be apparent to those of ordinary skill in the art that various changes and modifications within the spirit, scope and concept of the technical features set forth in the appended claims. Think it's obvious.

Claims (18)

A multi-trigger negative photoresist composition, comprising: a. at least one polymer, each of which includes two or more cross-linkable functional groups, at least 90% of which are acid-labile protecting groups connected; b. at least one acid-activated cross-linking agent; c. at least one of a photoacid generator or a thermal acid generator; and d. a monomer, which is one or more compounds with the following structure:

_{wherein _} R ₃ and R ₄ are the same or different, and are branched or unbranched, substituted or unsubstituted, saturated or unsaturated monovalent alkyl chains with 1 to 16 carbon atoms, which may or may not have one or more heteroatoms are substituted into the chain, substituted or unsubstituted aromatic groups, heteroaromatic groups, fused aromatic or fused heteroaromatic groups, aralkyl groups, cycloaliphatic groups, or A cyclic, bicyclic or polycyclic ring formed when any 2 or more of R ₁ , R ₂ , R ₃ and R ₄ are covalently linked to each other; and the group -N=R ₃ ' This is used to mean an amine in which the R ₃ group is linked by a double bond. The photoresist composition of claim 1 further includes a mixture of monomers having structures I-IV. The photoresist composition of claim 2, wherein at least one of X or Y includes: -(alkyl) _j -(aryl) _k -(O) _p -(COO) _q -ALPG where j, k, p , the value of q is as follows:

wherein alkyl is a branched or unbranched, substituted or unsubstituted, saturated or unsaturated divalent alkyl chain having 1 to 16 carbon atoms, with or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted aromatic group, heteroaromatic group or fused aromatic or fused heteroaromatic group, and ALPG is an acid-labile protecting group, and ALPG contains a leaving group . The photoresist composition of claim 3, wherein ALPG is a tertiary alkyl group, an alicyclic group, a ketal or a cyclic aliphatic ketal, or an acetal. The photoresist composition of claim 2, wherein the at least one photoacid generator includes an onium salt compound, a sulfonimide, a halogen-containing compound, a sulfonate, a sulfonyl imine, or a sulfonic acid. esters, quinonediazides, diazomethanes, oxime sulfonates, dicarboxyliminosulfates or mixtures thereof, when exposed to at least 10% of UV, deep UV, extreme UV, X-ray or electron beam actinic radiation One can produce acid. The photoresist composition of claim 2, wherein the at least one acid-activated cross-linking agent includes aliphatic, aromatic or aralkyl monomers, oligomers or polymers, including glycidyl ethers and glycidyl esters. , oxetane, glycidylamine, methoxymethyl group, ethoxymethyl group, butoxymethyl group, benzyloxymethyl group, dimethylaminomethyl group, diethyl Aminomethylamine group, dialkylmethylamine group, dibutoxymethylamine group, dihydroxymethylmethylamine group, dihydroxyethylmethylamine group, dihydroxy At least one of a butylmethylamine group, a morpholine methyl group, an acetyloxymethyl group, a benzyloxymethyl group, a formyl group, an acetyl group, a vinyl group or an isopropylene group. The photoresist composition of claim 2, further comprising a solvent, wherein the solvent includes ester, ether, ether-ester, hydroxyester, hydroxyether, ketone, ketone-ester, hydrocarbon, aromatic compound, halogenated solvent, Alkyl-aryl ethers or combinations thereof. The photoresist composition of claim 2, wherein the acid-labile protecting group can be removed when exposed to photoacid generation and optionally during post-exposure baking, providing that when the cross-linking agent is exposed A functional group capable of cross-linking with the cross-linking agent during the photoacid generation. The photoresist composition according to claim 2, wherein monomers (I), (II), (III) and (IV) have structures (V), (VI), (VII) or (VIII) respectively. Single body:

. The photoresist composition of claim 9, wherein at least one of X or Y includes: -(alkyl) _j -(aryl) _k -(O) _p -(COO) _q -ALPG where j, k, p , the value of q is as follows:

wherein alkyl is a branched or unbranched, substituted or unsubstituted, saturated or unsaturated divalent alkyl chain having 1 to 16 carbon atoms, with or without one or more heteroatoms substituted into the chain, aryl is a substituted or unsubstituted aromatic group, heteroaromatic group or fused aromatic or fused heteroaromatic group, and ALPG is an acid-labile protecting group, and ALPG contains a leaving group . The photoresist composition of claim 9, wherein ALPG is a tertiary alkyl group, an alicyclic group, a ketal or a cyclic aliphatic ketal, or an acetal. The photoresist composition of claim 9, further comprising a solvent, wherein the solvent includes ester, ether, ether-ester, hydroxyester, hydroxyether, ketone, ketone-ester, hydrocarbon, aromatic compound, halogenated solvent, Alkyl-aryl ethers or combinations thereof. The photoresist composition of claim 9, wherein the acid-labile protecting group can be removed when exposed to photoacid generation and optionally during post-exposure baking, providing that when the cross-linking agent is exposed A functional group capable of cross-linking with the cross-linking agent during the photoacid generation. A method for forming a patterned photoresist layer on a substrate, comprising the following steps: a. providing a substrate; b. applying the multi-trigger negative photoresist composition of claim 1 to a required wet thickness; c. heating the coating cloth substrate to form a dry coating to obtain the desired thickness; d. imagewise expose the coated substrate to one or more selected from UV, deep UV, extreme UV, X-ray or electron beam actinic radiation Actinic radiation; e. Removal of unexposed areas of the coating using an aqueous solvent, organic solvent, or combined aqueous-solvent developer composition; wherein the remaining photoimageable pattern is optionally heated. The method of claim 14, wherein when exposed to the acid under environmental conditions that provide functional groups capable of crosslinking with the crosslinking system when the crosslinking system is catalyzed by the acid, the acid Acid-labile protecting groups can be removed, wherein acid-labile protecting groups include tertiary alkoxycarbonyl groups. The method of claim 14, wherein the at least one photoacid generator includes an onium salt compound, a sulfonimide, a halogen-containing compound, a sulfonate, a quinonediazide, a diazomethane, and an oxime sulfonic acid. salt or dicarboxylic imine sulfate. The method of claim 14, wherein the at least one acid-activated cross-linking agent comprises a monomer, oligomer or polymer including glycidyl ether, glycidyl ester, glycidyl amine, methoxy methyl group, Ethoxymethyl group, butoxymethyl group, benzyloxymethyl group, dimethylaminomethyl group, diethylaminomethylamine group, dialkylmethylamine group, Dibutoxymethylamine group, dihydroxymethylmethylamine group, dihydroxyethylmethylamine group, dihydroxybutylmethylamine group, morpholine methyl group, acetyloxymethyl group group, benzyloxymethyl group, formyl group, acetyl group, vinyl group, isopropylene group or one or more glycidyl ether groups attached to an aryl monomer, oligomer or polymer At least one of the group. The method of claim 14, wherein the multi-trigger negative photoresist composition of claim 2 is applied to a required wet thickness in step b.