Photoresist composition and patterning method

Abstract

Disclosed herein is a photoresist composition comprising a nonionic thioxanthone compound, a nonionic oxime compound, or a combination of a nonionic thioxanthone compound and a nonionic oxime compound; a polymer comprising a first repeating unit having formula (3) and a second repeating unit having formula (4a): wherein in formula (3), R1 is a hydrogen atom or a substituted or unsubstituted C1 to C3 alkyl group; z is a non-hydrogen substituent comprising an acid labile moiety; and wherein in formula (4a), a is an integer from 1 to 5, and wherein Z2 is a hydrogen atom or a substituted or unsubstituted C1 to C5 alkyl group; an alkali quenching agent; a photoacid generator; and a solvent. # imgabs0 #

Description

BACKGROUND OF THE INVENTION

[0001] The present disclosure relates to a photoresist composition and a method for manufacturing the same. The present disclosure also relates to a patterning method for manufacturing a semiconductor, which prevents the development of a footing profile in a photoresist pattern.

[0002] For many years, mobile devices, devices as part of the Internet of Things (IoT), and wearable electronic devices have become smaller, lighter, and thinner. Despite their increasing miniaturization, they use larger amounts of memory and perform more and more computations.

[0003] The manufacturing and packaging of these electronic devices play an important role in size reduction. For example, the flip-chip packaging method has been used to increase the density of I / O (input / output) connections between devices, especially for microprocessing unit (MPU) and dynamic random access memory (DRAM) semiconductor chips.

[0004] Dry plasma etching is widely used in semiconductor manufacturing. The manufacturing of 3D-NAND devices requires the use of a thick film photoresist having durable etch resistance. 3D-NAND (three-dimensional NAND) is a flash memory technology used in data storage devices such as solid state drives (SSDs) and USB flash drives. The "3D" in 3D NAND refers to stacking memory cells in multiple layers to form a vertical structure.

[0005] When meeting the technical specifications of a thick film photoresist, there is a tendency to increase the pattern height and decrease the width. To address these technical specifications, chemically amplified photoresists (CARs) are employed.

[0006] In a plasma etching process involving a chemically amplified photoresist (CAR), a concern is the presence of ultraviolet (UV) emission, which activates the photoacid generator (PAG) present in the photoresist composition. The acid generated by activating the photoacid generator decomposes the acid-labile groups in the polymer, which accumulates and aggregates inside the photoresist film. After exceeding the critical point, these aggregates may cause bubbling or bursting. Even when the degree of degassing is low, when inspected using scanning microscopy, it may appear as voids.

[0007] A potential solution to mitigate the degassing problem is to reduce the amount of acid-labile components present in the photoresist composition. However, this adjustment negatively affects the dissolution rate, which proves less favorable for thick film applications. Another method to mitigate this problem is to increase the quencher base loading in the photoresist composition. A higher quencher loading has been shown to effectively reduce the severity of bubbling. However, this reduction comes at the cost of sensitivity.

[0008] Therefore, it is desirable to improve dry-etch resistance by maintaining sensitivity while reducing void formation and / or blistering caused by UV emission during plasma etching. SUMMARY OF THE INVENTION

[0009] Disclosed herein is a photoresist composition comprising a nonionic thioxanthone compound, a nonionic oxime compound, or a combination of a nonionic thioxanthone compound and a nonionic oxime compound; a polymer comprising a first repeating unit having formula (3) and a second repeating unit having formula (4a): wherein in formula (3), R1 is a hydrogen atom or a substituted or unsubstituted C1 to C3 alkyl group; Z is a non-hydrogen substituent comprising an acid-labile moiety; and wherein in formula (4a), a is an integer from 1 to 5, and wherein Z 2 is a hydrogen atom or a substituted or unsubstituted C1 to C5 alkyl group; a base quencher; a photoacid generator; and a solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A Depicts an exemplary embodiment of a substrate having a first layer disposed thereon;

[0011] Figure 1B Depicts an exemplary embodiment of the deposition of a photoresist layer on the first layer and the photolithographic patterning of the photoresist layer and the first layer;

[0012] Figure 1C Depicts an exemplary embodiment of the development of the photoresist layer;

[0013] Figure 1D Depicts the etching of the first layer by plasma dry etching;

[0014] Figure 2 Depicts in graphical form the effect of thioxanthone loading on the unexposed film thickness loss (UFTL) (lower figure), the energy to reach a -100 nm deviation from the nominal mask size (middle figure), and the process window at a -100 nm mask deviation from a 1200 nm nominal (upper figure);

[0015] Figure 3A Depicts the Bossung curve of a photoresist composition without ITX (photoresist composition CF-7 from Table 1);

[0016] Figure 3B Depicts the Bossung curve of a photoresist composition containing ITX (photoresist composition EX-5 from Table 1);

[0017] Figure 4A The focused exposure matrix process window (PW) of Comparative Example CF-7 (which does not contain ITX) is illustrated, aiming to achieve a space width of 1.1 μm using a 1.2 μm nominal mask;

[0018] Figure 4B The focused exposure matrix process window (PW) of, for example, EX-5 (which contains ITX) is illustrated, aiming to achieve the same space width using the same nominal mask as in Figure 4A ;

[0019] Figure 5 A series of graphs are depicted that depict the effects of nonionic oxime compounds on the unexposed film thickness loss (UFTL) (lower graph), sensitivity (middle graph), and process window (upper graph) of a photoresist composition containing a nonionic oxime additive;

[0020] Figure 6 Table 6 is included, which depicts scanning electron micrographs of cross-sectional images of different wafers after plasma etching. Detailed Description

[0021] As used herein, the terms "a / an" and "the" do not denote a limitation of quantity and are construed to include both the singular and the plural unless otherwise indicated herein or clearly contradicted by the context. Unless otherwise expressly stated, "or" means "and / or".

[0022] As used herein, an "acid-labile group" refers to a group in which a bond is cleaved by the catalytic action of an acid (optionally and typically together with heat treatment), resulting in the formation of a polar group (such as a carboxylic acid or alcohol group) on the polymer, and optionally and typically the moiety connected to the cleaved bond is disconnected from the polymer. Such an acid is typically a photoacid that causes bond cleavage during post-exposure baking. Suitable acid-labile groups include, for example: tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of an alkyl and an aryl group, 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", "acid-leaving groups", "acid-decomposable groups", and "acid-sensitive groups".

[0023] In lithography, the term "underdosed area" refers to an area under exposure conditions where the amount of light or radiation used to expose a photoresist is intentionally reduced to below the standard or optimal dose. This is a controlled variation of the nominal exposure conditions. The exposure dose in lithography can be used to define the desired pattern on the photoresist. Underdosing involves intentionally reducing the exposure energy during the lithography process. This method is sometimes used to explore the sensitivity limits of the photoresist or to intentionally cause changes in pattern dimensions.

[0024] The term "process window" refers to the range of process conditions, such as exposure dose, focal length, and depth of focus, within which the manufacturing process is robust and the desired pattern is formed consistently and accurately on the photoresist. "Improved process window" means an expansion or enhancement of this range, resulting in more forgiving and reliable manufacturing conditions.

[0025] The term "thioxanthone" includes nonionic sulfur-containing heterocyclic compounds containing a thioether group (S atom) in their structure. It includes nonionic derivatives of thioxanthone.

[0026] The term "oxime" includes nonionic oximes and their derivatives. It includes nonionic oxime esters, oxime ethers, and their derivatives.

[0027] Disclosed herein is a photoresist composition useful for plasma dry etching. The photoresist composition reduces the presence of voids and other forms of photoresist damage and exhibits an improved process window. The photoresist composition comprises a polymer containing acid-labile groups, a nonionic thioxanthone compound and / or a nonionic oxime compound, a photoacid generator, and a base quencher. The nonionic thioxanthone compound and / or the nonionic oxime compound improves the process window as compared to a photoresist composition containing all the same components except the nonionic thioxanthone compound and / or the nonionic oxime compound. The nonionic thioxanthone compound and / or the nonionic oxime compound enables the photoresist composition to have an improved process window at an exposure wavelength of 300 to 400 nanometers.

[0028] Without being bound by theory, it is believed that the nonionic thioxanthone compound absorbs some of the UV radiation to which the photoresist composition is exposed during the plasma etching process. The absorption of the UV radiation reduces the acid generated by the photoacid generator, thereby improving the process window. The nonionic oxime compound generates a base quencher upon exposure to UV radiation, and the base quencher effectively quenches the acid generated during the etching process. The quenching of the acid is beneficial for improving the process window. It also improves the tolerance to dry plasma etching.

[0029] The above photoresist composition is disposed on a substrate to form a photoresist layer. The photoresist layer is exposed to actinic radiation in a patterned manner. Then, the exposed photoresist layer is developed with an alkaline developer, thereby removing portions of the photoresist layer to form a relief pattern. The relief pattern serves as a mask during dry plasma etching.

[0030] As described above, in a plasma etching process, the acid generated by activating a photoacid generator decomposes the acid-labile groups in the polymer. Excess acid may accumulate inside the photoresist film, eventually causing bubbling (formation of voids) or bursting out of the film. The nonionic thioxanthone compound and / or nonionic oxime compound enable the photoresist composition to exhibit improved etch resistance by reducing the number of such voids. These compounds absorb UV emission and reduce the decomposition of the PAG during plasma etching, thereby affecting the formation of voids by preventing the cleavage of the acid-labile polymer.

[0031] Figures 1A - 1D A method of forming a pattern on a substrate using dry etching is depicted. Figure 1A A substrate 100 having a first layer 102 disposed thereon is depicted. Figure 1B Coating a photoresist layer 106 on the first layer 102 and subsequently exposing the photoresist layer 106 are depicted. The photoresist layer 106 contains a photoacid generator and a polymer containing acid-labile groups. After coating the photoresist layer 106, the photoresist layer 106 is exposed to actinic radiation 108 in a patterned manner through a photomask 110 having optically opaque regions and optically transparent regions. UV light with a wavelength of 10 to 400 nanometers is used for photolithographic patterning.

[0032] Figure 1C Development of the exposed portion of the photoresist layer 106 is depicted. The exposed portion of the photoresist layer 106 is removed via an aqueous alkaline developer, as visible from Figure 1C Then, the exposed portions of the first layer 102 and / or the substrate 100 are removed by dry plasma etching, as visible from Figure 1D During dry plasma etching, the photoresist layer 106 (with the exposed portion removed) serves as an etch mask. The etch mask exposes portions of the first layer 102 and / or the substrate 100 such that these portions can be removed during etching. Substrate

[0033] Examples of substrates include, but are not limited to, silicon wafers, glass substrates, and plastic substrates, which optionally include one or more layers or features formed thereon. A preferred substrate is a silicon wafer. First layer

[0034] Figure 1A Depicts a substrate 100 having a first layer 102 disposed thereon. The first layer 102 is selectively removed by dry plasma mask etching. The first layer comprises a metal, a ceramic, or a combination thereof. The metal includes aluminum, copper, titanium, silicon, or a combination thereof. The ceramic includes silicon oxide, silicon nitride, titanium nitride, or a combination thereof. In an embodiment, the first layer may include a stack of multiple layers, wherein the alternating layers comprise silicon oxide and silicon nitride. The stack may include 10 to 500 such alternating layers. Photoresist layer

[0035] Figure 1B Depicts the deposition of a photoresist layer 106 on the first layer 102 to be etched. The photoresist composition 106 comprises a polymer containing acid-labile groups; a photoacid generator; a quencher; and a solvent. The polymer comprises a first repeating unit containing acid-labile groups. In an embodiment, the polymer comprises a second repeating unit containing vinyl aromatic groups. In an embodiment, the polymer comprises a first repeating unit having formula (3) and a second repeating unit having formula (4a): wherein in formula (3), R1 is a hydrogen atom or a substituted or unsubstituted C1-C3 alkyl group; Z is a non-hydrogen substituent containing an acid-labile moiety; and wherein in formula (4a), "a" is an integer including 1 to 5, and wherein Z 2 is a hydrogen atom or a C1-C5 alkyl group.

[0036] An acid-labile group is a chemical moiety that undergoes a deprotection reaction in the presence of an acid. Deprotection of some acid-labile groups used in examples is caused by heat. Acetal protecting groups readily undergo deprotection at room temperature. The solubility of the polymer in the photoresist composition changes, which is a result of reaction with an acid generated by a photoacid generator (contained in the photoresist composition) after soft baking, exposure to actinic radiation, and post-exposure baking. This is due to a change in the polarity of the polymer caused by cleavage of the acid-labile groups induced by the photoacid. Acid-labile groups may be selected from, for example, tertiary alkyl carbonates, tertiary alkyl esters, tertiary alkyl ethers, acetals, and ketals. Preferably, the acid-labile group is an ester group containing a tertiary acyclic alkyl carbon or a tertiary cycloaliphatic carbon covalently linked to the carboxy oxygen of the ester of the polymer. Cleavage of such acid-labile groups results in the formation of a carboxylic acid group.

[0037] In one embodiment, the polymer containing acid-labile groups comprises a polymerization unit having the structure shown in formula (1) below: wherein Z is selected from a hydrogen atom, a substituted or unsubstituted C1-C4 alkyl group, a substituted or unsubstituted C1-C4 fluoroalkyl group, or a cyano group; Z 1 is a non-hydrogen substituent containing an acid-labile group, and cleavage of the acid-labile group forms a carboxylic acid on the polymer.

[0038] In an embodiment, the acid-labile group that forms a carboxylic acid group on the polymer after decomposition is preferably a tertiary ester group having the formula -C(O)OC(R1)3 or an acetal group having the formula -C(O)OC(R2)2OR3, wherein: each R1 is independently a straight-chain C1-20 alkyl group, a branched C3-20 alkyl group, a monocyclic or polycyclic C3-20 cycloalkyl group, a straight-chain C2-20 alkenyl group, a branched C3-20 alkenyl group, a monocyclic or polycyclic C3-20 cycloalkenyl group, a monocyclic or polycyclic C6-20 aryl group, or a monocyclic or polycyclic C2-20 heteroaryl group, preferably a straight-chain C1-6 alkyl group, a branched C3-6 alkyl group, or a monocyclic or polycyclic C3-10 cycloalkyl group, each of which is substituted or unsubstituted, each R1 optionally contains one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and any two R1 groups together optionally form a ring; R2 is independently hydrogen, fluorine, a straight-chain C1-20 alkyl group, a branched C3-20 alkyl group, a monocyclic or polycyclic C3-20 cycloalkyl group, a straight-chain C2-20 alkenyl group, a branched C3-20 alkenyl group, a monocyclic or polycyclic C3-20 cycloalkenyl group, a monocyclic or polycyclic C6-20 aryl group, or a monocyclic or polycyclic C2-20 heteroaryl group, preferably hydrogen, a straight-chain C1-6 alkyl group, a branched C3-6 alkyl group, or a monocyclic or polycyclic C3-10 cycloalkyl group, each of which is substituted or unsubstituted, each R2 optionally contains one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and the R2 groups together optionally form a ring; and R3 is a straight-chain C1-20 alkyl group, a branched C3-20 alkyl group, a monocyclic or polycyclic C3-20 cycloalkyl group, a straight-chain C2-20 alkenyl group, a branched C3-20 alkenyl group, a monocyclic or polycyclic C3-20 cycloalkenyl group, a monocyclic or polycyclic C6-20 aryl group, or a monocyclic or polycyclic C2-20 heteroaryl group, preferably a straight-chain C1-6 alkyl group, a branched C3-6 alkyl group, or a monocyclic or polycyclic C3-10 cycloalkyl group, each of which is substituted or unsubstituted, R3 optionally contains one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and one R2 and R3 together optionally form a ring. Such monomers are typically vinyl aromatic compounds, (meth)acrylates, or norbornyl monomers.

[0039] Suitable units containing acid-labile groups include, for example, acid-labile (alkyl) acrylate units such as tert-butyl (meth)acrylate, 1-methylcyclopentyl (meth)acrylate, 1-ethylcyclopentyl (meth)acrylate, 1-isopropylcyclopentyl (meth)acrylate, 1-propylcyclopentyl (meth)acrylate, 1-methylcyclohexyl (meth)acrylate, 1-ethylcyclohexyl (meth)acrylate, 1-isopropylcyclohexyl (meth)acrylate, 1-propylcyclohexyl (meth)acrylate, methyladamantyl (meth)acrylate, ethyladamantyl (meth)acrylate, etc., and other cyclic and acyclic (alkyl) acrylates including alicyclics.

[0040] Acetal and ketal acid-labile groups can be replaced by a base-soluble group such as a hydrogen atom at the carboxyl terminus to bond to an oxygen atom. When an acid is generated, the acid cleaves the bond between the acetal or ketal group and the oxygen atom to which the acid-dissociable dissolution-inhibiting group of the acetal type is bonded. Exemplary such acid-labile groups are described in, for example, U.S. Patent Nos. US6057083, US 6136501, and US 8206886, and European Patent Publication Nos. EP 01008913 A1 and EP 00930542A1. Also suitable are acetal and ketal groups that are part of a sugar-derived structure (the cleavage of which will result in the formation of a hydroxyl group), such as those described in U.S. Patent Application No. US 2012 / 0064456 A1.

[0041] Suitable polymers include, for example, phenolic resins containing acid-labile groups. Such particularly preferred resins include: (i) polymers containing polymerization units of vinylphenol and the acid-labile (alkyl) acrylate as described above, such as the polymers described in U.S. Patent Nos. 6,042,997 and 5,492,793; (ii) polymers containing polymerization units of vinylphenol, optionally substituted vinylphenyl (such as styrene) without a hydroxyl or carboxyl ring substituent, and the acid-labile (alkyl) acrylate as described above, such as the polymers described in U.S. Patent No. 6,042,997; (iii) polymers containing repeating units comprising an acetal or ketal moiety that will react with a photoacid and optionally aromatic repeating units (such as phenyl or phenol groups); such polymers are described in U.S. Patent Nos. 5,929,176 and 6,090,526; and blends of (i) and / or (ii) and / or (iii). Such polymers can be used for imaging at wavelengths of, for example, 200 nm or greater (such as 248 nm and 365 nm).

[0042] Suitable polymers include those that can be used for imaging at wavelengths below certain 200 nm (such as 193 nm), such as those disclosed in European Patent Publication No. EP 930542 A1 and U.S. Patent Nos. 6,692,888 and 6,680,159. For imaging at 193 nm wavelength, the polymer is preferably substantially free (e.g., less than 15 mol%) and preferably completely free of phenyl, benzyl or other aromatic groups, where such groups highly absorb radiation.

[0043] Other suitable polymers for photoresist compositions include, for example, those containing polymeric units of non-aromatic cyclic olefins (internal ring double bonds) (such as optionally substituted norbornene), such as the polymers described in U.S. Patent Nos. 5,843,624 and 6,048,664. Still other suitable polymers for photoresist compositions include polymers containing polymeric anhydride units, particularly polymeric maleic anhydride units and / or itaconic anhydride units, as disclosed in European Published Application EP 01008913 A1 and U.S. Patent No. 6,048,662.

[0044] Also suitable for use in photoresist compositions are polymers containing repeating units that contain heteroatoms, particularly oxygen and / or sulfur (but not anhydrides, i.e., the unit does not contain keto ring atoms). The heterocycloaliphatic units can be fused to the polymer backbone and can include fused carbocycloaliphatic units (such as provided by the polymerization of norbornene groups) and / or anhydride units (such as provided by the polymerization of maleic anhydride or itaconic anhydride). Such polymers are disclosed in International Publication No. WO0186353 A1 and U.S. Patent No. 6,306,554. Other suitable polymers containing heteroatom groups include polymers that contain polymeric carbocyclic aryl units (such as hydroxynaphthyl) substituted by one or more groups containing heteroatoms (e.g., oxygen or sulfur), as disclosed in U.S. Patent No. 7,244,542.

[0045] The polymer can further contain units containing lactone moieties for controlling the dissolution rate of the polymer and the photoresist composition. Suitable monomers for polymers containing lactone moieties include, for example, the following:

[0046] In embodiments, the polymer further typically contains units containing polar groups that enhance the etch resistance of the polymer and the photoresist composition and provide an additional means for controlling the dissolution rate of the polymer and the photoresist composition. Monomers for forming such units include, for example, the following:

[0047] The polymer may include one or more additional units of the above types. Typically, the additional units for the polymer will include polymerizable groups that are the same as or similar to the polymerizable groups used in the monomers of the other units used to form the polymer, but may include other different polymerizable groups in the same polymer backbone.

[0048] The polymer may also include one or more polymerized repeating units derived from vinyl aromatic monomers. Exemplary vinyl aromatic monomers are styrene. In an embodiment, the polymer derived from a vinyl aromatic monomer has a structure represented by the following formula (4a): where a is from 1 to 5, and where Z 2 is hydrogen or an alkyl group having 1 to 5 carbon atoms. In a preferred embodiment, a is 1 and Z 2 is hydrogen. Preferably, the vinyl aromatic monomer has a hydroxyl group at the para position on the aromatic ring. A preferred vinyl aromatic polymer is poly(p-hydroxystyrene) (abbreviated as PHS).

[0049] In an embodiment, the polymer for use in a photoresist composition includes a first repeating unit having formula (3) and a second repeating unit having formula (4): where R1 is a hydrogen atom or a substituted or unsubstituted C1-C3 alkyl group; Z is a non-hydrogen substituent containing an acid-labile moiety. In an embodiment, m + n (in formulas (3) and (4)) is from 70 to 100 mole percent (mol%). In an embodiment, based on the total polymerized units present in the polymer, m is from 10 to 90 mol%, preferably from 15 to 50 mol%, preferably from 20 to 40 mol%, and n is from 10 to 80 mol%, preferably from 20 to 75 mol%, and more preferably from 60 to 70 mol%. In an embodiment, the molar ratio of n to m is from 0.7 to 9, preferably from 0.2 to 4.

[0050] When the polymer includes a third repeating unit (different from the first and second repeating units), the third repeating unit may be present in the polymer in an amount of from 5 to 35 mol% and preferably from 10 to 30 mol% based on the total polymerized units present in the polymer.

[0051] Although not limited thereto, exemplary polymers include, for example, the following:

[0052] Suitable polymers for the photoresist composition are commercially available and can be readily prepared by those skilled in the art. The polymer is present in the photoresist composition in an amount sufficient to render the exposed coating of the photoresist developable in a suitable developer solution.

[0053] Typically, the polymer is present in the photoresist composition in an amount of 70 to 100 wt% based on the total solids of the photoresist composition. The weight-average molecular weight Mw of the polymer is typically less than 100,000, for example, 4000 to 100,000, more typically 4000 to 20,000 grams per mole (g / mol), as measured by gel permeation chromatography using polystyrene standards. Blends of two or more of the above-described polymers can be suitably used in the photoresist composition of the present invention.

[0054] The photoresist composition contains a nonionic photoacid generator. In embodiments, the photoresist composition may optionally contain an ionic photoacid generator. It is desirable to use a photoacid generator that generates a photoacid by Norrish-1 cleavage. The Norrish-I reaction is the photochemical cleavage or homolysis of aldehydes and ketones into two radical intermediates. The carbonyl group accepts a photon and is excited to a photochemical singlet state. In embodiments, the photoacid generator has the structure shown in formula (5) wherein in formula (4), R4 is a hydrogen atom, a substituted or unsubstituted straight-chain or branched C1 to C 14 alkyl group, a substituted heterocyclic group, or a halogen atom; and wherein R5 is a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms; a halogen atom, or an aryl group having 6 to 20 unsubstituted carbon atoms.

[0055] Examples of suitable photoacid generators are N-hydroxynaphthalenedicarboximide trifluoromethanesulfonate (NHNI-TF), N-hydroxynaphthalenedicarboximide perfluoro-1-butanesulfonate (NHNI-PFBS), N-hydroxynaphthalenedicarboximide camphor-10-sulfonate, N-hydroxynaphthalenedicarboximide 2-trifluoromethylbenzenesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide perfluoro-1-butanesulfonate, N-(trifluoromethylsulfonyloxy)phthalimide, N-hydroxysuccinimide perfluorobutanesulfonate or phenylacetonitrile, 2-methyl-α-[2-[[(propylsulfonyl)oxy]imino]-3(2H)-thiophenemethylene]-(commercially available as IRGACURE PAG 103). In a preferred embodiment, the photoacid generator can be one or more of the structures of formula (5a) or (5b) shown below:

[0056] The photoacid generator is present in the photoresist composition in an amount of 0.2 to 15 wt%, more typically 0.3 to 5 wt%, and more preferably 0.5 to 3 wt% based on the total solids of the photoresist composition. By minimizing the photoacid generator loading, the UV transparency of the photoresist can also be minimized. It increases the UV transparency of the photoresist layer.

[0057] As described above, the photoresist composition contains a nonionic thioxanthone compound and / or a nonionic oxime compound to improve the process window and prevent the formation of voids during dry plasma etching. The nonionic thioxanthone compound can be used alone or in combination with the nonionic oxime compound in the photoresist composition. The nonionic thioxanthone compound has the structure of formula (6) wherein R is a non-hydrogen substituent; each T is independently a hydrogen atom, a substituted or unsubstituted C 1-5 alkyl group, amino group, mercapto group or hydroxyl group; and each m is independently an integer from 0 to 4. In an embodiment, each T is independently a hydrogen atom or a substituted or unsubstituted C 1-3 alkyl group. In another embodiment, the nonionic thioxanthone compound is 2-isopropylthioxanthone, diethylthioxanthone, or a combination thereof.

[0058] The nonionic thioxanthone compound can be used in the photoresist composition in an amount of 0.05 to 3 wt%, preferably 0.08 to 2 wt%, and more preferably 0.1 to 1.5 wt% based on the total solids of the photoresist composition.

[0059] In an embodiment, the nonionic oxime compound has formula (7A) wherein in formula (7A), R 21 is a hydrogen atom, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted C 2-20 alkenyl group, a substituted or unsubstituted C 6-30 aryl group, a substituted or unsubstituted C 3-30 heteroaryl group, a substituted or unsubstituted C 7-20 arylalkyl group, a substituted or unsubstituted C 4-20 heteroarylalkyl group, or a combination thereof, R 21 optionally contains a -C(O)- group bonded to an O atom; R 22 and R 23 are each independently a hydrogen atom, a substituted or unsubstituted C 1-20 alkyl group, a substituted or unsubstituted C 3-20 cycloalkyl group, a substituted or unsubstituted C 2-20Alkenyl, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C 3-30 Heteroaryl, substituted or unsubstituted C 7-20 Arylalkyl, substituted or unsubstituted C 4-20 Heteroarylalkyl; or a combination thereof; provided that R 22 and R 23 cannot both be hydrogen atoms; and R 22 and R 23 optionally connect to each other via a single bond or a divalent linking group to form a ring. The ring formed by the fusion of R 22 and R 23 can include one of the following structures.

[0060] In an embodiment, R21 contains a -C(O)- group bonded to an O atom, and R22 and R23 connect to each other via a single bond or a divalent linking group to form a ring.

[0061] In an embodiment, R22 and R23 can be used to form fluorene.

[0062] In an embodiment, preferred nonionic oximes include 1-(2-naphthyl)ethanone O-(2-phenylacetyl)oxime (sometimes also called (E)-1-(naphthalen-2-yl)ethan-1-one O-(2-phenylacetyl)oxime (hereinafter referred to as oxime A)) and (9H-fluoren-9-one, O-(2-phenylacetyl)oxime) (sometimes also called 9H-fluoren-9-one O-(2-phenylacetyl)oxime) (hereinafter referred to as oxime B).

[0063] The nonionic oxime compound can be used in the photoresist composition in an amount of 0.1 to 1.5 wt%, preferably 0.2 to 1 wt%, based on the total solid content of the photoresist composition.

[0064] The photoresist composition further contains a base quencher. The base quencher improves the resolution of the developed resist relief image. However, the nonionic photoacid generator listed as an example decomposes in the presence of a basic substance. Therefore, a lower alkalinity is beneficial to prevent the decomposition of the photoacid generator during the storage of the photoresist composition.

[0065] The base quencher is selected from N-diethyldodecanamide, 2,8-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine (tropine), 1,1-dimethylethyl 4-hydroxypiperidine-1-carboxylate, N-allylcaprolactam, ethyl 3-(morpholino)propionate, 4-(p-tolyl)morpholine, or a combination thereof. The preferred base quencher is 2,8-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine (tropine).

[0066] The amount of the base quencher in the photoresist layer is preferably 0.001 to 1.0 wt%, more preferably 0.01 to 0.8 wt%, or 0.02 to 0.2 wt% based on the total weight of the solids in the photoresist composition. Solvent

[0067] The photoresist composition further comprises a solvent. The solvent is used to solvate the polymers used in the composition and to promote the miscibility of the various components used in the composition.

[0068] Solvents generally suitable for dissolving, dispensing, and coating include anisole, alcohols (including 1-methoxy-2-propanol (also known as propylene glycol methyl ether, PGME) and 1-ethoxy-2-propanol), esters (including n-butyl acetate, 1-methoxy-2-propyl acetate (also known as propylene glycol methyl ether acetate, PGMEA), methoxyethyl propionate, ethoxyethyl propionate), ketones (including cyclohexanone, 2,6-dimethyl-4-heptanone, 2-heptanone); ethyl lactate (EL), methyl 2-hydroxyisobutyrate (HBM), γ-butyrolactone (GBL), methyl 3-methoxypropionate, and combinations thereof.

[0069] The amount of the solvent can be, for example, 20 to 98 wt%, preferably 40 to 90 wt%, and more preferably 60 to 80 wt% based on the total weight of the photoresist composition. It should be understood that "polymer" as used in the context of the components in the photoresist layer can only mean the polymers disclosed herein (which contain acid-labile groups). It will be understood that the total solids include the polymer, the base quencher, the surfactant (if used), the photoacid generator, and any optional additives (excluding the solvent). The solids content of the composition can be 2 to 80 wt%, preferably 10 to 60 wt% based on the total weight of the photoresist composition.

[0070] The photoresist composition can contain other optional components, such as one or more surface leveling agents (SLA), adhesion promoters, and / or plasticizers. If used, the SLA is preferably present in an amount of 0.001 to 0.1 wt% based on the total weight of the solids in the photoresist composition, and if used, the adhesion promoter and / or plasticizer are each present in an amount of 0.1 to 10 wt% based on the total weight of the solids in the photoresist composition.

[0071] The photoresist composition further comprises a weakly acidic or weakly basic compound that promotes control of the influence of the substrate. When the photoresist is disposed on a metal substrate (such as copper), a footing profile is typically generated in the photoresist. These weakly acidic or weakly basic compounds form a passivation layer on the metal surface, which reduces the influence of the footing profile. If used, the weakly acidic or weakly basic compound is present in an amount of 0.001 to 0.1 wt% based on the weight of the solids of the photoresist composition.

[0072] The photoresist composition is applied onto the first layer 102 to form a photoresist layer 106. In an embodiment, the photoresist layer has a thickness greater than 2 microns. The photoresist composition is generally applied onto the surface of the metal layer via spin coating, dipping, roll coating, or some other conventional coating technique. Spin coating is preferred. For spin coating, the solids content of the coating solution can be adjusted based on the specific coating equipment used, the viscosity of the solution, the speed of the coating tool, and the amount of time allowed for rotation to provide the desired film thickness. In an embodiment, the photoresist composition is applied in a single application.

[0073] Then the photoresist composition layer is exposed to actinic radiation through a photomask in a patterned manner to create a solubility difference between the exposed and unexposed regions. Referring to Figure 1B , after depositing the photoresist layer 106, a mask 110 is disposed on the photoresist layer 106 so as to perform photolithography on the photoresist layer 106. UV light having a wavelength of 10 to 500 nanometers can be used in the photolithography. The exposed portion of the photoresist layer can be removed by an aqueous alkaline developer (such as 2.38 wt% tetramethylammonium hydroxide), followed by a water rinse and spin drying, as Figure 1C seen.

[0074] The exposure of the photoresist composition layer to radiation that is activating to the layer as mentioned herein indicates that the radiation is capable of forming a latent image in the layer. The photomask has optically transparent and optically opaque regions that respectively correspond to the regions of the resist layer to be exposed and not exposed by the actinic radiation. The exposure wavelength is typically below 500 nm, such as 200 to 500 nm of UV-visible light. Preferably, the exposure is performed with radiation of the 365 nm wavelength (i-line) of a mercury lamp.

[0075] After the exposure of the photoresist composition layer, post-exposure baking (PEB) is typically performed to decompose the acid-labile groups by the acid generated by the PAG during the exposure step. The PEB can be performed, for example, on a hot plate or in an oven. Thereby, a latent image defined by the boundary between the polarity-converted and non-converted regions (corresponding to the exposed and unexposed regions respectively) is formed.

[0076] Next, the photoresist composition layer is contacted with an alkaline developer solution to remove the exposed portions of the layer, thereby forming a resist pattern in the unexposed areas. The developer is typically an aqueous alkaline developer, such as a quaternary ammonium hydroxide solution, e.g., a tetraalkylammonium hydroxide solution, such as a 0.26 normal (N) (2.38 wt%) tetramethylammonium hydroxide (TMAH).

[0077] Another aspect is a process for dry plasma etching of a first layer 102. The first layer 102 is partially removed by using a photoresist relief pattern as an etch mask. After dry plasma etching, any remaining portions of the photoresist composition can be removed (stripped) from the substrate.

[0078] An advantage of the present invention is that the photoresist composition can be used to obtain a wider process window in a lithography process to form an etch mask. The etch mask formed from the photoresist then has greater tolerance to the etching process by reducing the formation of voids caused by outgassing of acid-labile groups of the polymer.

[0079] The present invention will now be illustrated by the following non-limiting examples. Examples Example 1

[0080] This example was conducted to determine the process window of photoresist compositions that do not contain a nonionic thioxanthone compound or a nonionic oxime compound, contain a nonionic thioxanthone compound or a nonionic oxime compound, or contain both a nonionic thioxanthone compound and a nonionic oxime compound. These compositions contain one of additive A and additive B to control the pattern profile. Either additive is beneficial for removing the footing profile.

[0081] For this example, the photoacid generator (PAG-1) is N-hydroxynaphthalenedicarboximide trifluoromethanesulfonate. The base quencher (base A) is Troger's base. Additive A is 1H-1,2,3-benzotriazole. Additive A has a lower basicity than the base quencher. Additive B is trithiocyanuric acid. 2-Isopropylthioxanthone (ITX) and diethylthioxanthone (DETX) are nonionic thioxanthone compounds that reduce the photoacid generated by the photoacid generator. Nonionic oxime compounds that improve the process window (e.g., additives that generate base quenchers that improve the process window) include 1-(2-naphthyl)ethanone O-(2-phenylacetyl)oxime (also known as oxime A) and (9H-fluoren-9-one, O-(2-phenylacetyl)oxime) (also known as oxime B). The structures of all of the above materials are shown below.

[0082] All samples contain 0.02 wt% of POLYFOX PF-656, with a PGMEA / GBL of 98 / 2 by weight.

[0083] The acid-labile polymer of the photoresist composition has a weight-average molecular weight (Mw) of 23,000 grams per mole and contains 35 mole percent of tert-butanol and 65 mole percent of polyhydroxystyrene. Table 1 shows samples of the photoresist composition with solid contents shown in parts by weight (pbw).

[0084] The comparative photoresist compositions shown in Table 1 are CF-5 to CF-8. These comparative compositions do not contain an oxime or thioxanthone. The exemplary compositions EX-1 to EX-21 contain one of a nonionic oxime compound or a nonionic thioxanthone compound or both a nonionic oxime compound and a nonionic thioxanthone compound.

[0085] A 150-nm-thick titanium layer is deposited on a 150-mm silicon substrate. Then, a 200-nm-thick copper layer is deposited on the titanium layer by sputtering. The surface of the copper layer is washed with a 10 wt% sulfuric acid (H2SO4) solution for 30 seconds to remove the surface oxide layer, followed by rinsing with deionized (DI) water. Then, the water is removed by blowing a pressurized nitrogen stream onto the substrate. The substrate is puddle-wetted with a 2.38 wt% TMAH solution for 60 seconds, followed by rinsing with deionized water. Then, the substrate is spin-dried. No primer is used on the copper layer.

[0086] Then, the photoresist composition is spin-coated onto the substrate using a D-Spin 60A SK-W60A-AVP wafer track (Sokudo Corporation). After soft baking at 135 °C for 90 seconds, the spin speed is adjusted to obtain a 7.5-micron (μm)-thick photoresist layer.

[0087] Then, the photoresist layer is mask-exposed through an NSR-2005i9C (Nikon Corporation) light source with a numerical aperture of 0.50 NA. The post-exposure bake (PEB) and development processes are applied through a Clean Track Mk-Vz (Tokyo Electron Limited). The PEB process is applied at 110 °C for 90 seconds. Then, the photoresist layer is puddle-developed in a 2.38 wt% TMAH aqueous developer (MFTM CD-26, DuPont Electronics & Industrial) for 80 seconds. After development, the substrate is then rinsed with water and spin-dried. The term "puddle development" typically refers to a specific development technique used in photoresist processing. Puddle development involves allowing the developer solution to pool or form a "puddle" on the surface of the photoresist during the development step.

[0088] During the mask exposure step of the lithography process (Focus Exposure Matrix = FEM), the stability of pattern width against focus position and energy intensity variations was evaluated using a 1.2 μm trench mask. The aim was to evaluate a pattern width that is 100 nm narrower than the nominal size, with a focus on the underdose process window. The process window was quantified as the focus tolerance, which provides a 5% exposure margin corresponding to a ±10% variation of the target pattern size (1210 nm to 990 nm). Calculations were performed using ProData software via KLA-TENCOR.

[0089] Table 2 presents the results of the lithography tests and the process window evaluation. To evaluate the impact of analogs of both nonionic oxime and nonionic thioxanthone compounds, their loadings were depicted as relative values with respect to the PAG molar amount, as shown in Table 2. Table 1 Table 2 Effect of adding thioxanthone to the photoresist composition

[0090] The impact of thioxanthone additives in the photoresist composition was evaluated by: a) using the thioxanthone additive alone in the form of a single additive (ITX) in an amount suitable for alleviating footing on the copper substrate; or b) splitting the total amount used in (a) and adding it in the form of two different additives (ITX and DETX). Figure 2 The impact of nonionic thioxanthone loading on the unexposed film thickness loss (UFTL) (lower figure), the energy to reach a -100 nm deviation from the nominal mask size (middle figure), and the process window at a -100 nm mask deviation from the 1200 nm nominal (upper figure) was depicted in a graphical form. The use of nonionic thioxanthone compounds resulted in a reduction in unexposed film thickness loss (UFTL) and a decrease in sensitivity, as Figure 2 shown. This trend persisted when comparing different types of thioxanthone (ITX and DETX) or different additives (benzotriazole and trithiocyanuric acid). Notably, as a weak base in iCAR, benzotriazole exhibited a slower sensitivity (Eop, the energy to reach the 1200 nm nominal mask size).

[0091] Figure 3A and 3B The pattern space width was depicted against variations in focus position and exposure energy, as shown by the Poisson curve. Figure 3Adepicts the Poisson curve of a photoresist composition without ITX (photoresist composition CF-7 from Table 1), while Figure 3B depicts the curve of a photoresist composition containing ITX (photoresist composition EX-5 from Table 1). The exposure tool uses "msec" as the unit of exposure energy. It is the exposure time and is almost equal to 1 / 2 mJ / cm 2 . The Poisson curve (also known as the focus exposure matrix or process window) is a graphical representation used in lithography to analyze the performance of the lithography process. This figure illustrates how the critical dimension (CD) of a pattern (such as the width of a line) changes with both the focus position and the exposure energy during the lithography exposure step. The x-axis of the Poisson curve typically represents the focus position, indicating the position of the photoresist layer relative to the focal plane of the imaging system in the vertical direction. The y-axis represents the exposure energy, which is the amount of light or other radiation used during exposure. The Poisson curve helps to determine the optimal conditions for producing a pattern with the desired dimensions. Compared with the composition without ITX ( Figure 3A , based on CF-7), the addition of ITX ( Figure 3B , based on EX-5) results in a narrower pattern width variation with respect to changes in both the exposure energy and the focus position. In other words, when compared with an equivalent control composition (CF-7) containing the same components but without ITX, (for the photoresist composition containing ITX (EX-5)) the pattern width tends to stabilize with an increase in the exposure energy.

[0092] Figure 4A and 4B illustrate examples of process window graphs using a nominal mask size of 1200 nm. Figure 4A Illustrates the focus exposure matrix process window (PW) of the control example CF-7 (which does not contain ITX), aiming to achieve a space width of 1.1 μm using a 1.2 μm nominal mask. Figure 4B Illustrates the focus exposure matrix process window (PW) of, for example, EX-5 (which contains ITX), aiming to achieve the same space width using the same nominal mask. The process window is designed to have a 5% exposure margin, which allows for a ±10% pattern size variation relative to the target size. As previously in Figure 3BAs can be seen, when compared to an equivalent comparative composition (CF-7) having the same components but without ITX, the pattern width (for the photoresist composition (EX-5) containing ITX) tends to stabilize as the exposure energy increases. In this evaluation, the process window was determined at a lower exposure energy, resulting in a deviation of -100 nm (1100 nm) compared to the nominal mask size (1200 nm). A pattern width tolerance of plus or minus 10% relative to the target size was considered, and the exposure latitude was calculated at each focus offset. It is defined as the ratio of the difference between the exposure energy for the plus 10% pattern size (E+10%, 1210 nm = 1100 nm × 110%) and the minus 10% (E-10%, 990 nm) to the energy of the target size (E-100 nm deviation, 1100 nm).

[0093] The focus range providing a 5% EL margin was used as the process window in this evaluation. Unexpectedly, the addition of the nonionic thioxanthone compound tended to result in a wider process window. For example, CF7 and EX5 have the same formulation except for the nonionic thioxanthone compound. As indicated in the graph, the addition of ITX resulted in more stable changes in the critical dimension (CD) with respect to both exposure energy and focus position (offset). By maintaining plus or minus 10% of the pattern width change, EX5 produced a process window of 0.96 μm compared to under-sized patterns (see Figure 4B for the oval region). This represents an almost two-fold improvement in the process window compared to the baseline CF7 (0.49 μm) (see Figure 4A for the oval region). Effect of adding oxime to the photoresist composition

[0094] The lithographic performance of the nonionic oxime additives 1-(2-naphthyl)-ethanone, O-(2-phenylacetyl)oxime (oxime A) and (9H-fluoren-9-one, O-(2-phenylacetyl)oxime) (oxime B) was evaluated in the photoresist composition. The test results from Table 2 showed that the addition of the nonionic oxime compound increased the process window with and without the nonionic thioxanthone compound.

[0095] Figure 5 A series of graphs are depicted that depict the effect of the oxime compound on the unexposed film thickness loss (UFTL) (lower graph), sensitivity (energy to reach -100 m deviation, middle graph), and process window (PW deviation -100 nm, upper graph) of the photoresist composition containing the oxime additive. Figure 5 Data from EX-5, EX-11, EX-12, EX-14, and EX-19 from Table 2 are depicted.

[0096] Figure 5 It has been shown that a photoresist composition containing an increased amount of a nonionic oxime compound (such as oxime A) exhibits a reduced amount of UFTL. This trend is similar to that observed when a nonionic thioxanthone compound is incorporated into the photoresist composition (see Figure 2 ). Additionally, by introducing a nonionic oxime compound in addition to a baseline formulation already containing a nonionic thioxanthone compound, the process window is further expanded. Example 2

[0097] The effects of nonionic thioxanthone and nonionic oxime compounds on dry-etch resistance were evaluated. The process conditions and plasma etching conditions are detailed in Tables 4 and 5, respectively. Table 6 ( Figure 6 as shown) presents the wafer appearance after plasma etching and the corresponding cross-sectional SEM images.

[0098] As can be seen from Table 6, sample CF-7 (see Table 1) that contains neither thioxanthone (ITX) nor oxime compound (oxime A) exhibits bubbles on its surface. The addition of ITX or oxime A results in a reduction in the number and size of these bubbles, indicating an improvement. When examining the cross-section by scanning electron microscopy (SEM), small and round voids were observed, with their size being smaller closer to the photoresist surface. The introduction of ITX or oxime A further reduces the size and thickness of the void distribution in the surface. Table 4 Substrate Silicon Primer HMDS (Hexamethyldisilazane) Pre - bake 135°C / 90 seconds Film thickness 10μm Exposure i - line, NSR - 2005i9C, 0.50NA / 0.68PC P.E.B 110°C / 90 seconds Developer <![CDATA[MF TM CD-26, 2.38 wt% TMAH, single water pit for 80 seconds]]> Table 5 Tool SAMCO, RIE - 10NR Gas flow <![CDATA[SF6 / O2 = 66 / 10 SCCM]]> RF power 250W Etching time 150 seconds

[0099] Without being bound by theory, the observed bubbles (in comparative sample CF-7) may be aggregates of minute voids generated by the degassing of acid-labile polymers in the photoresist. During plasma etching, UV emission can play an important role in generating photoacid from a photoacid generator (PAG). This photoacid is thought to decompose acid-labile groups, serving as a source of degassing.

[0100] As demonstrated above, both nonionic thioxanthone (ITX) and oxime compound (oxime A) contribute to a wider process window, especially in the underdose region. Both methods result in lower UFTL and slower sensitivity. The slower sensitivity can provide better control over the exposure process, thus allowing for more precise development of the pattern.

Claims

1. A photoresist composition comprising: A nonionic thioxanthone compound, a nonionic oxime compound, or a combination of a nonionic thioxanthone compound and a nonionic oxime compound; A polymer comprising a first repeating unit having formula (3) and a second repeating unit having formula (4a): wherein in formula (3), R1 is a hydrogen atom or a substituted or unsubstituted C1 to C3 alkyl group; Z is a non-hydrogen substituent containing an acid-labile moiety; and wherein in formula (4a), a is an integer from 1 to 5, and wherein Z 2 is a hydrogen atom or a substituted or unsubstituted C1 to C5 alkyl group; Alkaline quencher; photoacid generators; and Solvent.

2. The photoresist composition according to claim 1, wherein The nonionic thioxanthone compound has a structure of formula (6): wherein R is a non-hydrogen substituent; each T is independently a hydrogen atom, a substituted or unsubstituted C 1-5 alkyl, amino, mercapto or hydroxyl; and each m is independently an integer from 0 to 4.

3. The photoresist composition according to claim 2, wherein Each T is independently a hydrogen atom or a substituted or unsubstituted C 1-3 alkyl.

4. The photoresist composition according to any one of claims 1 to 3, wherein The nonionic thioxanthone compound is 2-isopropylthioxanthone, diethylthioxanthone, or a combination thereof.

5. The photoresist composition according to claim 1, wherein The nonionic oxime compound has the formula (7A) In formula (7A), R 21 is a hydrogen atom, a substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 3-20 Cycloalkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C 3-30 Heteroaryl, substituted or unsubstituted C 7-20 Arylalkyl, substituted or unsubstituted C 4-20 heteroarylalkyl, or a combination thereof, R 21 optionally containing a -C(O)- group bonded to an O atom; R 22 and R 23 are independently a hydrogen atom, a substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 3-20 Cycloalkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C 3-30 Heteroaryl, substituted or unsubstituted C 7-20 Arylalkyl, substituted or unsubstituted C 4-20 heteroarylalkyl; or a combination thereof; provided that R 22 and R 23 cannot all be hydrogen atoms; and R 22 and R 23 They are optionally linked to each other via a single bond or a divalent linking group to form a ring.

6. The photoresist composition according to claim 5, wherein R 21 Contains a -C(O)- group bonded to an O atom.

7. The photoresist composition according to any one of claims 5 or 6, wherein R 22 and R 23 They are linked to each other via a single bond or a divalent linking group to form a ring.

8. The photoresist composition according to any one of claims 1 to 7, wherein The photoacid generator is selected from N-hydroxynaphthalene dicarboxylic acid imide trifluoromethanesulfonate, N-hydroxynaphthalene dicarboxylic acid imide perfluoro-1-butanesulfonate, N-hydroxynaphthalene dicarboxylic acid imide camphor-10-sulfonate, N-hydroxynaphthalene dicarboxylic acid imide 2-trifluoromethylbenzenesulfonate, N-hydroxy-5-norbornene-2,3-dicarboxylic acid imide perfluoro-1-butanesulfonate, N-(trifluoromethanesulfonyloxy)phthalimide and N-hydroxysuccinimide perfluorobutanesulfonate.

9. The photoresist composition according to any one of claims 1 to 8, wherein The base quencher is selected from N-diethyl dodecanamide, 2,8-dimethyl-6H,12H-5,11-methylenedibenzo[b,f][1,5]diazocine (trogol base), 4-hydroxypiperidine-1-carboxylic acid 1,1-dimethylethyl ester, N-allyl caprolactam, ethyl-3-(morpholino) propionate, 4-(p-tolyl)morpholine, or a combination thereof.

10. A patterning method comprising: providing a substrate; forming a photoresist layer on the substrate, wherein the photoresist layer is formed from the photoresist composition according to any one of claims 1 to 9; exposing the photoresist layer to activating radiation in a pattern-wise manner; as well as The photoresist layer is contacted with a developing solution to form a photoresist pattern.

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