Photoresist composition and pattern forming method

Abstract

Disclosed herein is a method of forming a pattern, the method comprising: (a) applying a layer of a photoresist composition on a semiconductor substrate, (b) exposing the layer of the photoresist composition to i-line radiation in a patterned manner; and (c) developing the exposed photoresist composition layer to provide a resist relief image; wherein the photoresist composition comprises a non-ionic photoacid generator; a solvent; a first polymer and a second polymer; and wherein the first polymer comprises a polymeric dye.

Description

BACKGROUND

[0001] The present disclosure relates to photoresist compositions and pattern forming methods. More specifically, photoresist compositions are particularly applied in the electronics industry for the manufacture of semiconductor devices. In particular, the present disclosure relates to photoresist compositions comprising a polymer having an anthracene chromophore.

[0002] Photoresist materials are photosensitive compositions used to transfer an image to one or more underlying layers, such as metal, semiconductor, or dielectric layers, disposed on a semiconductor substrate. To increase the integration density of semiconductor devices and to allow the formation of structures having dimensions in the nanometer range, photoresists and photolithography tooling with high resolution capabilities have been and continue to be developed.

[0003] Chemically amplified (CA) photoresists are conventionally used for high resolution processing. Such resists typically use a polymer with acid-labile groups and a photoacid generator. Exposure in a patterned fashion through a photomask to activating radiation causes the photoacid generator to form acid, which during a post-exposure bake causes the acid-labile groups in the exposed regions of the polymer to cleave. This creates a difference in solubility characteristics between the exposed and unexposed regions of the resist in the developer solution. In a positive tone development (PTD) process, the exposed regions of the photoresist layer are soluble in the developer and are removed from the substrate surface, while the unexposed regions, which are insoluble in the developer, remain after development to form a positive image.

[0004] With the continued growth of the packaging industry, there has been a significant increase in the demand for thick layer resists in recent years. Such applications use thick resist coatings of 10 μιη to about 100 μιη. The exposure tools used in these applications employ i-line (365 nanometers (nm)) and longer wavelength radiation (g-line to h-line).

[0005] For thick layer resists, it is desirable to minimize overhang. An overhang profile is a profile in which the sidewall angle is greater than 90° (degrees). In other words, when comparing the width of the photoresist pattern at the surface and the bottom using a scanning electron microscope cross-sectional image, the width at the surface is narrower than the width at the bottom.

[0006] It is desirable to develop photoresist compositions with faster sensitivity and reduced overhang. SUMMARY

[0007] Disclosed herein is a method of patterning, the method comprising: (a) applying a layer of a photoresist composition on a semiconductor substrate, (b) exposing the layer of the photoresist composition to i-line radiation in a patterned manner; and (c) developing the exposed photoresist composition layer to provide a resist relief image; wherein the photoresist composition comprises a non-ionic photoacid generator; a solvent; a first polymer comprising a first polymeric unit of formula (1), a second polymeric unit of formula (2), and a third polymeric unit of formula (3):

[0008]

[0009] wherein a is 1 to 5 and Z 3 is hydrogen or an alkyl group having 1 to 5 carbon atoms, Z and R 5 are independently selected from a hydrogen atom, a C1-C4 alkyl group, a C1-C4 fluoroalkyl group, or a cyano group; Z 1 is a non-hydrogen substituent comprising an acid labile group whose cleavage forms a carboxylic acid on the polymer; L is a divalent linking group; Ar1 is a substituted or unsubstituted anthracene group; wherein the first polymer is present in the photoresist composition in an amount of 0.1 wt% to 10 wt% based on the total solids of the photoresist composition; and a second polymer comprising a first polymeric unit of formula (4):

[0010]

[0011] wherein b is 1 to 5 and Z 3 is hydrogen or an alkyl group having 1 to 5 carbon atoms; and a second polymeric unit of a monomer comprising an acid labile group; and wherein the second polymer is free of polymeric units of formula (3), is present in the photoresist composition in an amount of 10 wt% to 99 wt% based on the total solids of the photoresist composition. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1A is a plot depicting film loss in unexposed areas (dark etch);

[0013] Figure 1B is a plot depicting sensitivity (E op ) shift as a function of polymer dye (first polymer) loading;

[0014] Figure 2 is a plot showing that the addition of the first polymer (containing an anthracene substituent) improves the absorbance (Abs) of the photoresist at the i-line wavelength (365 nm);

[0015] Figures 3A to 3D A cross-sectional profile plot of Example 1 is described.

[0016] Figures 4A to 4E Sections 5A to 5E and 6A to 6E describe the cross-sectional profiles in Example 2.

[0017] Figures 7A to 7D 8A to 8D, 9A to 9D, and 10A to 10D describe the cross-sectional profiles in Example 3.

[0018] Figures 11A to 11D The cross-sectional profile of Example 4 is described. Detailed Implementation

[0019] As used herein, the terms “a / an” and “described” do not indicate a limitation of quantity and are to be construed as including both the singular and plural unless otherwise indicated herein or clearly contradicted by the context. Unless otherwise explicitly stated, “or” means “and / or”.

[0020] As used herein, an "acid-instable group" refers to a group in which a bond is broken by the catalytic action of an acid (optionally and typically in conjunction with heat treatment), resulting in a polar group (such as a carboxylic acid or alcohol group) formed on the polymer, and optionally and typically a portion attached to the broken bond that breaks off from the polymer. Such acids are typically photogenerated acids where bond cleavage occurs during post-exposure baking. Suitable acid-instable groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, or ketal groups. Acid-instable groups are also commonly referred to in the art as "acid-crackable groups," "acid-crackable protecting groups," "acid-instable protecting groups," "acid-leaving groups," "acid-instable groups," and "acid-sensitive groups."

[0021] "Substituted" means that at least one hydrogen atom on a group is replaced by another atom or group, provided that the valence of the specified atom is not exceeded. When the substituent is an oxo group (i.e., =O), both hydrogen atoms on the carbon atom are replaced. Combinations of substituents or variables are permitted. Exemplary groups that may exist at the "substituted" position include, but are not limited to, nitro (-NO2), cyano (-CN), hydroxyl (-OH), oxo (=O), amino (-NH2), mono- or di-(C 1-6 )alkylamino, alkanoyl (such as C 2-6 Alkyl groups (such as acyl groups), formyl groups (-C(=O)H), carboxylic acids or their alkali metal or ammonium salts; esters (including acrylates, methacrylates and lactones) such as C 2-6 Alkyl esters (-C(=O)O-alkyl or -OC(=O)-alkyl) and C 7-13Aryloxy (-O-aryl), C 1-6 Alkyl), carboxamido (-CH2C(=O)NR2, where R is hydrogen or C 1-6 Alkyl), halogen, mercapto (-SH), C 1-6 Alkylthio (-S-alkyl), thiocyano (-SCN), C 1-6 Alkyl, C 2-6 Alkenyl, C 2-6 Alkynyl, C 1-6 Haloalkyl, C 1-9 Alkoxy, C 1-6 Haloalkoxy, C 3-12 Cycloalkyl, C 5-18 Cycloalkenyl, C 6-12 Aryl (e.g., phenyl, biphenyl, naphthyl, etc., each ring aromatic, substituted or unsubstituted), C 7-19 Arylalkyl, arylalkoxy, C 7-12 Alkylaryl, C 4-12 Heterocycloalkyl, C 3-12 Heteroaryl, C 1-6 Alkylsulfonyl (-S(=O)2-alkyl), C 6-12 Arylsulfonyl (-S(=O)2-aryl), or tosyl (CH3C6H4SO2-). When a group is substituted, the indicated number of carbon atoms is the total number of carbon atoms in the group, not including those of any substituents. For example, the group -CH2CH2CN is a C2alkyl group that is substituted with a cyano group.

[0022] In this specification, “(meth)acrylate” means “at least one of acrylate and methacrylate.” Additionally, “(meth)acrylic acid” means “at least one of acrylic acid and methacrylic acid.”

[0023] As used herein, the term “alkyl” means a branched or straight-chain saturated aliphatic hydrocarbon group having the specified number of carbon atoms. As used herein, the term C1-C6alkyl indicates an alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms. Other embodiments include alkyl groups having 1 to 8 carbon atoms, 1 to 4 carbon atoms, or 1 or 2 carbon atoms, e.g., C1-C6alkyl, C1-C4alkyl, and C1-C2alkyl. When C0-C nWhen an alkyl group is used in conjunction with another group (e.g., (cycloalkyl)Co-C4alkyl), the indicated group (in this case, a cycloalkyl group) can be bonded directly through a single covalent bond (Co) or attached through an alkyl chain having the specified number of carbon atoms, in this case, 1, 2, 3, or 4 carbon atoms. Examples of alkyl groups include, but are not limited to: methyl, ethyl, n-propyl, i-propyl, n-butyl, 3-methylbutyl, t-butyl, n-pentyl, and sec-pentyl.

[0024] As used herein, the term "cycloalkyl" indicates a saturated hydrocarbon ring group having only carbon ring atoms and having the specified number of carbon atoms (typically having 3 to about 8 ring carbon atoms or 3 to about 7 carbon atoms). Examples of cycloalkyl groups include: cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl as well as bridged or caged saturated ring groups such as norbornane or adamantane.

[0025] As used herein, the term "heterocycloalkyl" denotes a saturated ring group containing 1 to about 3 heteroatoms selected from N, O, and S, the remaining ring atoms being carbon. Heterocycloalkyl groups have 3 to about 8 ring atoms, and more typically 5 to 7 ring atoms. Examples of heterocycloalkyl groups include morpholinyl, piperazinyl, piperidinyl, and pyrrolidinyl. The nitrogen in a heterocycloalkyl group can optionally be quaternized.

[0026] In references to groups and radicals in this specification, where a group is indicated without explicit statement of whether that group is substituted or unsubstituted, then that group includes groups and radicals both without substituents (unsubstituted) and with substituents (substituted). For example, "alkyl" indicated without statement of whether it is substituted or unsubstituted includes not only alkyl groups without substituents (unsubstituted alkyl), but also alkyl groups with substituents (substituted alkyl).

[0027] As used herein, the term "aryl" means an aromatic group containing only carbon in one or more aromatic rings. Typical aryl groups contain 1-3 separate, fused, or pendant rings and 6 to about 18 ring atoms, without heteroatoms as ring members. When indicated, such aryl groups can be further substituted with carbon or non-carbon atoms or groups. Bicyclic aryl groups can be further substituted with carbon or non-carbon atoms or groups. Bicyclic aryl groups can contain two fused aromatic rings (naphthyl) or an aromatic ring fused to a 5- to 7-membered non-aromatic ring group, optionally containing 1 or 2 heteroatoms independently selected from N, O, and S, such as 3,4-methylenedioxy-phenyl. Aryl groups include, for example, phenyl, naphthyl (including 1-naphthyl and 2-naphthyl), and biphenyl.

[0028] "Halo" or "halogen" is any of fluorine, chlorine, bromine, and iodine.

[0029] Disclosed herein is a photoresist composition comprising a non-ionic photoacid generator; an organic solvent; and a first polymer comprising first polymerized units of a first vinyl aromatic monomer, second polymerized units of a first ethylenically unsaturated double bond having an acid-labile pendant group, and third polymerized units of an ethylenically unsaturated double bond having a substituted or unsubstituted aromatic group containing three fused aromatic rings; and a second polymer comprising first polymerized units of a second vinyl aromatic monomer and second polymerized units of a second ethylenically unsaturated double bond having an acid-labile pendant group.

[0030] Also disclosed herein is a method of making and using the photoresist composition. The photoresist composition is made by blending the photoacid generator, the first polymer, and the second polymer in a solvent. The photoresist composition can optionally be filtered or passed through an ion exchange resin. Then, a layer (e.g., film) of the photoresist composition is applied on a semiconductor substrate. The photoresist composition layer is exposed to i-line radiation in a patterned manner. Then, the exposed photoresist composition layer is developed to provide a resist relief image.

[0031] The first polymer is typically a copolymer comprising three or more different repeating units. The copolymer can be a random copolymer, a block copolymer, a star block copolymer, a gradient copolymer, and the like, with a random copolymer being preferred.

[0032] The first polymerized units of the first polymer have the structure shown in the following formula (1):

[0033]

[0034] where a is 1 to 5 and where Z 3 is hydrogen or an alkyl group having 1 to 5 carbon atoms. In preferred embodiments, a is 1 and Z 3 is hydrogen. Preferred for the first polymerized units of the first polymer is a hydroxyl group located at the para position of the aromatic ring. A preferred first polymerized unit of the first polymer is poly(p-hydroxystyrene).

[0035] Typically, the first polymerized units of the first polymer are present in the first polymer in an amount of 30 mole % to 90 mole %, typically 50 mole % to 80 mole %, 55 mole % to 75 mole %, or 63 mole % to 75 mole %, based on the total repeating units of the first polymer.

[0036] The second polymerized units of the first polymer have the structure shown in the following formula (2):

[0037]

[0038] 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 comprising an acid labile group whose cleavage forms a carboxylic acid on the polymer. Additional details regarding Z and Z 1 are provided below. In the following formulae (2a) and (2b), Z is replaced by R.

[0039] In embodiments, the acid labile group that forms a carboxylic acid group on the polymer upon decomposition is preferably a tertiary ester group having the formula -C(O)OC(R 1 )3or an acetal group having the formula -C(O)OC(R 2 )2OR 3 , wherein: R 1 each independently is a linear C 1-20 alkyl group, a branched C 3-20 alkyl group, a monocyclic or polycyclic C 3-20 cycloalkyl group, a linear C 2-20 alkenyl group, a branched C 3-20 alkenyl group, a monocyclic or polycyclic C 3-20 cycloalkenyl group, a monocyclic or polycyclic C 6-20 aryl group, or a monocyclic or polycyclic C 2-20 heteroaryl group, preferably a linear C 1-6 alkyl group, a branched C 3-6 alkyl group, or a monocyclic or polycyclic C 3-10 cycloalkyl group, each of which is substituted or unsubstituted, each R 1 optionally includes one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and any two R 1 groups together optionally form a ring; R 2 independently is hydrogen, fluorine, a linear C 1-20 alkyl group, a branched C 3-20 alkyl group, a monocyclic or polycyclic C 3-20 cycloalkyl group, a linear C 2-20 alkenyl group, a branched C 3-20 alkenyl group, a monocyclic or polycyclic C 3-20 cycloalkenyl group, a monocyclic or polycyclic C 6-20 aryl group, or a monocyclic or polycyclic C 2-20 heteroaryl group, preferably hydrogen, a linear C 1-6 alkyl group, a branched C 3-6 alkyl group, or a monocyclic or polycyclic C 3-10 cycloalkyl group, each of which is substituted or unsubstituted, each R 2 optionally includes one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and R2 The groups optionally form a ring together; and R 3 It is a straight chain C 1-20 Alkyl, branched C 3-20 alkyl, monocyclic or polycyclic C 3-20 cycloalkyl, straight-chain C 2-20 Alkenyl, branched C 3-20 alkenyl, monocyclic or polycyclic C 3-20 Cycloalkenyl, monocyclic or polycyclic C 6-20 aryl, or monocyclic or polycyclic C 2-20 Heteroaryl groups, preferably linear C 1-6 Alkyl, branched C 3-6 Alkyl, or monocyclic or polycyclic C 3-10 Cycloalkyl, each of which is substituted or unsubstituted, R 3 Optionally, it includes one or more groups selected from -O-, -C(O)-, -C(O)-O-, or -S- as part of its structure, and an R 2 With R 3 They can optionally form a ring together. Such monomers are typically vinyl aromatic compounds, (meth)acrylates, or norbornyl monomers.

[0040] Suitable monomers containing such acid-instable groups include monomers of formulas (2a) and (2b):

[0041]

[0042] Where: R is hydrogen, C is... 1-4 Alkyl, or C 1-4 Fluoroalkyl groups, typically hydrogen or methyl; R 1 R 2 and R 3 It is as defined above; L 1 It is a divalent linking group containing at least one carbon atom, typically C. 1-10 Alkylene, such as C 1-10 straight-chain alkylene, C 3-10 Branched alkylene, or C 3-10 Cyclic alkylene groups, or combinations thereof, each of which may be substituted or unsubstituted, and may contain one or more heteroatoms, such as O, S, or N; and wherein n is 0 or 1. In a preferred embodiment, n is 0.

[0043] Suitable monomers containing acid-labile groups include structures such as those shown below:

[0044]

[0045]

[0046]

[0047] wherein R is as defined above in formula (2a) and (2b).

[0048] The total content of the polymeric units of formula (2) in the first polymer is typically 1 to 65 mole %, more typically 5 to 50 mole % or 5 to 30 mole %, based on the total number of moles of the first polymer. A preferred monomer for forming the second polymeric units is tert-butyl methacrylate.

[0049] The third polymeric unit of the first polymer has the structure shown in the following formula (3):

[0050]

[0051] wherein L is a divalent linking group, wherein R 5 is selected from a hydrogen atom, a C1-C4 alkyl group, a C1-C4 fluoroalkyl group, or a cyano group, and wherein Ar1is a substituted or unsubstituted anthracene group. Examples of divalent linking groups include substituted or unsubstituted alkylene groups, which preferably have 1 to about 4 carbons. In preferred embodiments, the divalent linking group is unsubstituted methylene.

[0052] In embodiments, the third polymeric unit has the structure shown in the following formula (3a):

[0053]

[0054] wherein L is a divalent linking group, wherein R 5 is as defined above and each R 4 may independently be a hydrogen, a halogen (F, Cl, Br, I); a substituted or unsubstituted alkyl group, which preferably has 1 to about 12 carbon atoms; a substituted or unsubstituted alkoxy group, which preferably has 1 to about 12 carbon atoms; a substituted or unsubstituted alkenyl group, which preferably has 2 to about 12 carbon atoms; a substituted or unsubstituted alkynyl group, which preferably has 2 to about 12 carbon atoms; a substituted or unsubstituted alkylthio group, which preferably has 1 to about 12 carbon atoms; a cyano group; a nitro group; an amino group; a hydroxyl group; m is an integer from 0 (where the anthracene ring is fully substituted with hydrogens) to 9. In embodiments, m is preferably 0, 1, or 2. In preferred embodiments of structure 3(a), L is unsubstituted methylene and m is 0. Preferred third polymeric units have the following structure:

[0055] wherein R 5 is a hydrogen.

[0056] The third polymeric unit is typically present in the first polymer in an amount of 5 to 30 mole %, typically 15 to 27 mole %, more typically 18 to 24 mole %, based on the total moles of the first polymer. Typically, the first polymer has a molecular weight of 5,000 to 15,000 g / mole.

[0057] In exemplary embodiments, the first polymer is a copolymer having a structure shown in Formula (4):

[0058]

[0059] wherein I, m, and n represent the mole content of each polymeric unit, and the sum is 100 mole %. In embodiments, I is 40 to 75 mole %, m is 8 to 16 mole %, and n is 5 to 30 mole %, based on the total moles of the copolymer. The total weight average molecular weight of the polymer of Formula (4) is typically 5,000 to 15,000 g / mole, preferably 7,500 to 12,500 g / mole, using polystyrene standards.

[0060] In embodiments, the first polymer (comprising the first, second, and third polymeric units) is present in the photoresist composition in an amount of 0.1 to 20 weight %, preferably 1 to 9 weight %, more preferably 3 to 8 weight %, based on the total solids of the photoresist composition.

[0061] The second polymer is a copolymer comprising first polymeric units of a vinyl aromatic monomer and second polymeric units of an acid-labile group-containing monomer, without comprising polymeric units of Formula (3). The second polymer can also be a random copolymer, a block copolymer, a star block copolymer, a gradient copolymer, and the like, with a random copolymer being preferred.

[0062] In embodiments, the vinyl aromatic polymeric units of the second polymer can be the same or different from the first (vinyl aromatic) polymeric units of the first polymer. In preferred embodiments, the vinyl aromatic polymeric units of the second polymer are different from the vinyl aromatic polymeric units of the first polymer either in chemical structure or in molecular weight.

[0063] In embodiments, the first polymeric units of the second polymer have a structure of Formula (5):

[0064]

[0065] wherein b is 1 to 5, and wherein Z 4 is hydrogen or an alkyl group having 1 to 5 carbon atoms. In preferred embodiments, b is 1 and Z 3is hydrogen. In preferred embodiments, the substituent is a hydroxyl group located at the para position of the aromatic ring. In preferred embodiments, the first polymeric unit of the second polymer is poly(p-hydroxystyrene).

[0066] In one embodiment, the first polymeric unit is present in the second polymer in an amount of 40 to 90 mole percent, typically 52 to 76 mole percent, more typically 55 to 72 mole percent, based on the total moles of the second polymer.

[0067] The second polymeric unit of the second polymer can be the same as or different from the second repeating unit of the first polymer described above in formula (2) or described below in formula (7). In embodiments, the second polymeric unit of the second polymer is different from the second polymeric unit of the first polymer either in chemical structure or in molecular weight.

[0068] The second polymer can alternatively comprise a second polymeric unit derived by polymerization of an ethylenically unsaturated monomer containing a phenolic group protected with an acetal or ketal group. In embodiments, the second polymeric unit of the second polymer can be derived from a monomer of formula (7):

[0069]

[0070] In formula (7), R b is hydrogen, fluorine, a substituted or unsubstituted C 1-5 alkyl group, or a substituted or unsubstituted C 1-5 fluoroalkyl group; each A is independently a halogen, a hydroxyl group, a carboxylic acid or ester, a mercapto group, a linear or branched C 1-20 alkyl group, a monocyclic or polycyclic C 3-20 cycloalkyl group, a monocyclic or polycyclic C 3-20 fluorocycloalkyl group, a monocyclic or polycyclic C 3-20 heterocycloalkyl group, a monocyclic or polycyclic C 6-20 aryl group, or a monocyclic or polycyclic C 4-20 heteroaryl group, each of which is substituted or unsubstituted; and m is independently an integer from 0 to 4. Preferably, R b is hydrogen or a methyl group, A is a hydroxyl group, and m is 0 or 1.

[0071] In formula (7), R 11 , R 10 , and R 8 are each independently hydrogen, a linear or branched C 1-20 alkyl group, a linear or branched C 1-20 heteroalkyl group, a monocyclic or polycyclic C 3-20 cycloalkyl group, a monocyclic or polycyclic C 3-20 heterocycloalkyl group, a monocyclic or polycyclic C 6-20 aryl group, or a monocyclic or polycyclic C7-20 aryloxyalkyl, or monocyclic or polycyclic C 4-20 Heteroaryl groups, each of which is substituted or unsubstituted. In the examples, R 11 R 10 and R 8 Any two of them can optionally form a ring. In another embodiment, the multi-ring structure can be formed by R 11 R 10 and R 8 They formed together.

[0072] In equation (7), R 7 It is a hydrogen, substituted or unsubstituted straight-chain or branched C 1-20 Alkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Cycloalkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Heterocyclic alkyl, substituted or unsubstituted C 6-14 aryl, substituted or unsubstituted C 3-14 heteroaryl, substituted or unsubstituted C 7-18 arylalkyl, substituted or unsubstituted C 4-18 Heteroarylalkyl, or substituted or unsubstituted C 1-12 Heteroalkyl groups.

[0073] In equation (7), R 9 It is a hydrogen, substituted or unsubstituted straight-chain or branched C 1-20 Alkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Cycloalkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Heterocyclic alkyl, substituted or unsubstituted C 6-14 aryl, substituted or unsubstituted C 3-14 heteroaryl, substituted or unsubstituted C 7-18 arylalkyl, substituted or unsubstituted C 4-18 Heteroarylalkyl, or substituted or unsubstituted C 1-12 Heteroalkyl. In one embodiment, R 7 and R 9 They are the same.

[0074] In equation (7), R 7 and R 9 They can be chosen to form a ring together.

[0075] In another embodiment, in equation (7), R 7 Or R 9 One of the optional R 8 R 10 Or R 11 A ring is formed.

[0076] For example, the second polymer can contain repeat units derived from a monomer of formula (7a):

[0077]

[0078] wherein R b , R 11 , R 10 and R 7 are the same as defined for formula (7). In one embodiment, R 10 and R 11 are not both hydrogen. In one aspect, R 10 and R 11 together optionally can form a ring. In another aspect, R 7 and R 10 or R 11 together optionally can form a ring.

[0079] Non-limiting examples of monomers having formula (7a) include:

[0080]

[0081] wherein R b is defined in formula (7) above.

[0082] In embodiments, the second polymer can include first polymerized units derived from a monomer of formula (5) and / or second polymerized units derived from a monomer of formula (2) and / or a monomer of formula (7).

[0083] In one embodiment, the second polymerized units are typically present in the second polymer in an amount of 10 to 40 mole %, preferably 12 to 39 mole %, more preferably 14 to 38 mole %, based on the total moles of the second polymer.

[0084] In exemplary embodiments, the second polymer is a copolymer having a structure shown in formula (8):

[0085]

[0086] wherein o is 40 to 90 mole %, preferably 54 to 70 mole %, more preferably 56 to 66 mole %, and p is 10 to 60 mole %, preferably 15 to 46 mole %, more preferably 20 to 42 mole %, and most preferably 25 to 38 mole %, based on the total mole content of the second polymer.

[0087] In embodiments, the second polymer can comprise three different repeat units, so long as it does not contain a polymeric unit of formula (3). In embodiments, the second polymer can comprise repeat units of formula (5) and / or (7).

[0088] In another exemplary embodiment, the second polymer is a copolymer having a structure shown in formula (9) to (12):

[0089]

[0090]

[0091]

[0092] wherein o is 50 mole % to 85 mole %, preferably 54 mole % to 70 mole %, more preferably 56 mole % to 67 mole %, and p is 5 mole % to 30 mole %, preferably 18 mole % to 24 mole %, and q is 10 mole % to 25 mole %, preferably 14 mole % to 18 mole %, based on the total mole content of the second polymer.

[0093] In embodiments, the second polymer has a higher average molecular weight than the first polymer. The second polymer has a weight average molecular weight of 5,000 g / mole to 50,000 g / mole, preferably 10,000 g / mole to 40,000 g / mole, and more preferably 14,000 g / mole to 25,000 g / mole.

[0094] In embodiments, the second polymer (comprising the first polymeric unit and the second polymeric unit) is present in the photoresist composition in an amount of 10 wt % to 99 wt %, based on the total solids of the photoresist composition.

[0095] The photoresist composition further comprises a non-ionic photoacid generator. In embodiments, the photoresist composition is free of ionic photoacid generators. It is desirable to use a photoacid generator that generates a photoacid through a 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 into a photochemical singlet state. In embodiments, the photoacid generator has a structure shown in formula (13):

[0096]

[0097] wherein in formula (13), R4is a hydrogen atom, a substituted or unsubstituted linear or branched C1to C 14 alkyl, a substituted heterocyclic group, or a halogen atom; and wherein R5is 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.

[0098] Examples of suitable photoacid generators are N-hydroxynaphthalimide trifluoromethanesulfonate (NHNI-TF), N-hydroxynaphthalimide perfluoro-1- butanesulfonate (NHNI-PFBS), N-hydroxynaphthalimide camphor-10- sulfonate, N-hydroxynaphthalimide 2-trifluoromethylbenzenesulfonate, N- hydroxy-5-norbornene-2,3-dicarboxylic acid imide perfluoro-1-butanesulfonate, N-(trifluoromethylsulfonyloxy)phthalimide, N-hydroxysuccinimide perfluorobutanesulfonate, or phenylacetonitrile, 2-methyl-a-[2-[[(propylsulfonyl)oxy] imino]-3(2H)-thiophenemethyl]-(commercially available as IRGACURE PAG 103). In preferred embodiments, the photoacid generator can be one or more of the structures of formula (13a), (13b), or (13c) below:

[0099]

[0100] The photoacid generator is present in the photoresist composition in an amount of 0.5 to 30 weight percent, more typically 0.7 to 20 weight percent, and more preferably 0.9 to 15 weight percent, based on the total solids of the photoresist composition.

[0101] The photoresist composition also includes a solvent. The solvent is used to solvate the polymer used in the composition and to promote miscibility of the various ingredients used in the composition. In some embodiments, the photoresist composition in solution includes the polymer in an amount of 5 to 80 weight percent, particularly 10 to 60 weight percent, more particularly 15 to 40 weight percent, based on the weight of the total solids. It will be understood that “polymer” used in this context of components in a resist can mean only the copolymer disclosed herein, or a combination of the copolymer with another polymer useful in photoresists. It will be understood that the total solids include the polymer, the photo-diable base, the quencher, the surfactant, any added PAG, and any optional additives (not including the solvent).

[0102] Solvents generally suitable for dissolution, 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), gamma-butyrolactone (GBL), 3-methoxypropyl methyl ether, and combinations thereof.

[0103] The amount of solvent can be, for example, 20 to 95 weight percent, preferably 40 to 90 weight percent, and more preferably 60 to 52 weight percent, based on the total weight of the photoresist composition.

[0104] The photoresist composition can further include a base quencher. The base quencher can include a non-photodegradable base such as those based on hydroxides, carboxylates, amines, imines, and amides. Preferably, the quencher includes a C 1-30 organic amine, imine, or amide, or a strong base (e.g., hydroxide or alkoxide) or a weak base (e.g., carboxylate)

[0105] In embodiments, the base quencher includes a first quencher and a second quencher.

[0106] The first quencher is effective to reduce footing profile problems at the bottom of the photoresist pattern on the metal layer. When a radiation-sensitive (photoresist) film is formed on a metal layer such as a copper or copper alloy layer, the photosensitivity of the film can be reduced at the interface region of the film and the metal layer. It is believed that the reduction in photosensitivity is due to the consumption of the generated photoacid by the metal ions formed at the resist film / metal layer interface in an electrochemical reaction (see Griffin et al., A Simple Phase Transition Model for Metal Passivation Kinetics, J. Electrochem. Soc, Vol. 131, No. 1, pp. 18-21). This is believed to result in a low photoacid concentration at the interface. As a result, the acid-catalyzed cleavage of the acid-labile portion of the resin at the resist / copper interface will not be as effective, and a footing will result. The first quencher is believed to be effective to inhibit the formation of metal ions at the resist film / metal layer interface.

[0107] The first quencher is selected from benzotriazole or a derivative thereof. Examples of benzotriazole derivatives include, but are not limited to, 1H-benzotriazole-1- methanol, 1 -aminobenzotriazole, 1 -(formamidomethyl)-1H-benzotriazole, 1 -(methoxymethyl)- 1H-benzotriazole, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert- octylphenyl)benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, and 5,6-dimethyl-1,2,3-benzotriazole hydrate. Preferably, benzotriazole, 1H-benzotriazole-1- methanol, 5-methyl-1H-benzotriazole, or 5,6-dimethyl-1,2,3-benzotriazole hydrate. The present inventors have found that benzotriazole or a derivative thereof prevents the formation of metal ions (such as copper ions) without reducing the sensitivity of the radiation-sensitive film.

[0108] The amount of the first quencher in the radiation-sensitive film is preferably 0.001 to 1.0% by weight, more preferably 0.005 to 0.2% by weight, and most preferably 0.01 to 0.1% by weight, based on the total weight of the solid.

[0109] The second quencher is believed to function as an acid diffusion control agent in the middle or upper surface region of the radiation-sensitive film to compensate for the relatively high volatility of the benzotriazole analog. When the radiation-sensitive film is formed without the use of the second quencher, the contact hole sidewall can have a tapered profile. In the formation of a metal pillar bump, straight and vertical sidewalls are highly advantageous. The second quencher is selected from amine compounds, but straight-chain and branched tertiary alkyl amines are excluded.

[0110] Examples of the second quencher include, but are not limited to, N,N-diethyldodecanamide, 2,8-dimethyl-6H,12H-5,11-methano dibenzo[b,f][1,5] diazocin (troger's base), 1,1-dimethylethyl 4-hydroxypiperidine-1-carboxylate, and N-allylcaprolactam.

[0111] The amount of the second quencher in the radiation-sensitive film is preferably 0.001 to 1.2% by weight, more preferably 0.01 to 0.8% by weight or 0.02 to 0.2% by weight, based on the total weight of the solid.

[0112] In an embodiment, the mole percent (expressed as a percentage) of the quencher to the photoacid generator is 5% to 50%, preferably 8% to 30%, and most preferably 10% to 15%.

[0113] The radiation-sensitive composition can include other optional ingredients, such as one or more surface leveling agents (SLAs), 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 solids of the composition, and the adhesion promoters and / or plasticizers are each present in an amount of 0.1 to 10 wt.%, based on the total solids of the composition.

[0114] A method of using the photoresist composition will now be described. In accordance with a patterning process, a layer of the photoresist composition is formed on a substrate. The composition can be applied to the substrate by spin coating, dip coating, roll coating, or other conventional coating techniques. Spin coating is preferred. For spin coating, the solids content of the coating solution can be adjusted based on the particular coating equipment used, the viscosity of the solution, the speed of the coating tool, and the amount of time allowed for spinning to provide the desired film thickness. In embodiments, the layer of photoresist composition is applied in a single application.

[0115] The layer of photoresist composition can then be soft baked to minimize the solvent content in the film, to form a tack-free coating, and to improve the adhesion of the layer to the substrate. Soft baking can be performed on a hot plate or in an oven, with a hot plate being typical.

[0116] The layer of photoresist composition is then exposed through a photomask to activating radiation in a patterned manner to create a solubility differential between exposed and non-exposed areas. Reference herein to exposing a layer of photoresist composition to radiation that is activating to the layer indicates that the radiation is capable of forming a latent image in the layer. The photomask has optically transparent and optically opaque areas corresponding to the areas in the resist layer that are to be exposed and not exposed, respectively, by the activating radiation. The exposure wavelength is typically below 500 nm, such as ultraviolet visible light of 200 to 500 nm. Preferably, the exposure is with radiation of 365 nm wavelength (i-line) of a mercury lamp.

[0117] Following exposure of the layer of photoresist composition, a post-exposure bake (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 is formed defined by the boundaries between the polarity-converted and unconverted areas, corresponding to the exposed and non-exposed areas, respectively.

[0118] The layer of photoresist composition is next contacted with an alkaline developer to remove the exposed portions of the layer, leaving the non-exposed areas to form a resist pattern. The developer is typically an aqueous alkaline developer, such as a quaternary ammonium hydroxide solution, for example, a tetraalkylammonium hydroxide solution, such as 0.26 normal (N) (2.38 wt.%) tetramethylammonium hydroxide (TMAH).

[0119] A further aspect of the present application is a method for depositing a metal on a metal layer. The method comprises: (i) forming a photoresist composition layer on the metal layer; (ii) exposing the photoresist composition layer to activating radiation in a patterned manner; (iii) a post-exposure bake step to decompose acid-labile groups; (iv) contacting the photoresist composition layer with an alkaline developer to remove exposed portions of the photoresist composition layer; and (v) immersing the metal layer in a metal plating solution and electrodepositing a metal on the metal layer in the exposed portions of the photoresist composition layer. The metal layer is typically formed on a substrate.

[0120] The metal layer can be composed of, for example, copper, silver, aluminum, gold or alloys thereof. The metal layer can also be referred to herein as a first metal layer. When forming the metal layer on a substrate, the metal layer can be formed using known methods, for example by chemical vapor deposition (CVD) or physical vapor deposition (PVD) techniques, wherein sputtering and plating are typical. The thickness of the metal layer is typically 10 nm to 1000 nm. Examples of substrates include, but are not limited to, silicon wafers, glass substrates and plastic substrates, such substrates optionally including one or more layers or features formed thereon.

[0121] The photoresist composition layer is formed from a photoresist composition as described herein, which comprises: a first polymer, a second polymer, optionally a quencher, a photoacid generator and a solvent. The photoresist composition is applied on the metal layer by known methods such as spin coating, roll coating or screen printing. In order to form a thick photoresist composition layer, a photoresist composition with a high solids content and / or a high viscosity is typically required. The solids content of the composition is typically 10 wt% to 60 wt%, preferably 20 wt% to 50 wt%, based on the total weight of the photoresist composition. By using such a composition, a thick layer of, for example, 50 nm to 50 micrometers, preferably 0.8 micrometers to 30 micrometers, and more preferably 1.2 micrometers to 10 micrometers, can be formed.

[0122] After applying the photoresist composition, a soft bake can be performed to minimize the solvent content in the layer and to improve the adhesion of the layer to the substrate. The photoresist composition layer is then exposed using radiation such as ultraviolet visible light (having a wavelength of 200 nm to 500 nm (nm)) or visible light through a mask having a predetermined pattern. Preferably, the exposure is carried out with radiation of 365 nm wavelength (i-line).

[0123] The photoresist composition layer is contacted with an alkaline developer to develop the exposed portions of the photoresist composition layer. Examples of alkaline developers include aqueous solutions of tetramethylammonium hydroxide, sodium hydroxide, and potassium hydroxide. The exposed portions can form a pattern, such as a hole (e.g., a contact, via, or bump pattern) or trench (e.g., line space) pattern. Such patterns preferably have a high aspect ratio. As used herein, the aspect ratio (AR) is defined as AR = h / d, where h is the photoresist height (i.e., thickness) and d is the pitch in the pattern, e.g., the hole diameter (e.g., for a contact, via, or bump pattern) or the length of the pitch between adjacent lines (e.g., for a trench pattern). Typically, the hole diameter can be 2 to 200 micrometers, preferably 10 to 50 micrometers. The aspect ratio is typically 0.1 or greater, 0.2 or greater, 0.1 to 10.0, or 0.2 to 7.0.

[0124] The substrate can next be immersed in a metal plating solution to plate a metal on the exposed first metal layer in those areas of the photoresist composition layer where the photoresist composition layer has been developed. The developed areas of the photoresist composition layer act as a mold for the metal plating. The metal can be plated, for example, by electroplating. Various types of metal plating solutions known in the art can be used. Additionally, two or more different metal layers can be formed, and the layers can be the same or different metal layers. Preferred plated metals include, but are not limited to, copper, nickel, tin, silver, gold, and mixtures and alloys thereof. Suitable metal plating solutions for forming such metals are known in the art and are commercially available from DuPont Electronic and Imaging. The thickness of the plated metal layer is typically 1 to 100 micrometers, preferably 20 to 50 micrometers. The plated metal layer thickness can be less than or exceed the thickness of the photoresist layer.

[0125] After the metal plating, the remaining photoresist composition layer can be removed (stripped) from the substrate. Suitable photoresist strippers are commercially available, such as Shipley BPR™ photo-stripper (DuPont Electronic and Imaging).

[0126] The exposed first metal layer between the plated metal structures can be removed, for example, by a back-etching process, to electrically isolate each of the plated metal structures. The resulting metal structures can, for example, have a columnar shape, which can be used as a metal bump to provide an electrical connection between two components. Advantageously, metal columns having a small diameter and straight (vertical) sidewalls can be formed by the compositions and methods disclosed herein. Such structures are used, for example, in electrical connections in small, light, and thin devices. The width (diameter) of the column can be, for example, 5 to 200 micrometers, preferably 10 to 50 micrometers. The height of the column will depend, for example, on the thickness of the photoresist composition resin, but a column height of 20 micrometers or greater can be formed.

[0127] The present application is advantageous in that the photoresist composition can be used for metal plating. It can also be used in dry etching processes to remove an underlying layer (e.g., metal, oxide, or nitride, etc.) in processes that do not always use a photoresist pattern.

[0128] Another aspect of the present application is a method for etching a metal, silicon (and / or its oxide or nitride), or a combination thereof. The method comprises: (i) forming a layer of a photoresist composition on the metal, silicon (and / or its oxide or nitride), or a combination thereof; (ii) exposing the layer of the photoresist composition to activating radiation in a patterned manner; (iii) post-exposure baking to decompose acid-labile groups; (iv) contacting the layer of the photoresist composition with an alkaline developer to remove exposed portions of the layer of the photoresist composition; and (v) etching the metal, silicon (and / or its oxide or nitride), or a combination thereof at locations where the photoresist was removed in the previous step. Typically, a dry plasma etching method or a wet etching method is used.

[0129] A photoresist layer is then formed as described above. If the photoresist layer is formed on a non-metal surface, the first quenching agent can not be used because it is to prevent pattern footing caused by the metal surface. Pattern footing describes the ease of ionization and the ease of migration of the ionized metal.

[0130] The present application will now be illustrated by the following non-limiting examples.

[0131] Example

[0132] Example 1

[0133] This example details the absorption characteristics of a photoresist composition containing a first polymer and a second polymer. The first polymer comprises first polymeric units of a first vinyl aromatic monomer, second polymeric units of a first ethylenically unsaturated double bond having an acid-labile pendant group, and third polymeric units of an ethylenically unsaturated double bond having a substituted or unsubstituted aromatic group containing three fused aromatic rings. The first polymer is also referred to herein as a polymeric dye due to the presence of the fused aromatic rings. The components of the photoresist composition are shown below.

[0134] The first polymer (also referred to as polymeric dye A) comprises:

[0135]

[0136] The second polymer comprising a copolymer of polyhydroxystyrene and poly(tert- butyl methacrylate) (denoted as PHS / TBA) is shown below.

[0137]

[0138] Photoacid generator

[0139]

[0140] Quencher

[0141]

[0142] The composition of the photoresist is described in parts by weight. The solvent is a mixture of propylene glycol methyl ether acetate (PGMEA) and gamma-butyrolactone (GBL). The solvent is present in an amount of 71.5 parts by weight. Propylene glycol methyl ether acetate and gamma-butyrolactone are used in a weight ratio of 95:5.

[0143] Anthracene acts as a dye to absorb incident light with i-line wavelength (365 nm). In the pre-bake step that is performed prior to exposure, anthracene undergoes strong sublimation when subjected to high temperature. To prevent sublimation, the anthracene chromophore is attached to the side chain of the acrylic repeat unit. This anthracene-containing polymer is called ANTMA (anthracene methacrylate). ANTMA has a unique ultraviolet spectrum between 320 nm and 420 nm. There is strong ultraviolet absorption near the i-line wavelength. The g-line (436 nm) and h-line (405 nm) ultraviolet absorption of anthracene is weaker than the i-line. The j-line (334 nm) can be absorbed by ANTMA. Photolithography experiments were performed using a 330 nm cut-off high pass filter.

[0144] A photoresist composition containing a first polymer, a second polymer, a quencher, a photoacid generator, and a solvent was first coated on a silicon substrate with a hexamethyldisilazane (HMDS) primer.

[0145] Table 1 shows the photoresist compositions used for the samples, while Table 2 shows the application and exposure conditions. The structures of the individual components used in the photoresist compositions are shown below.

[0146]

[0147] Table 2

[0148]

[0149] From the data in Table 1, it can be seen that the (photoresist) absorbance at the i-line wavelength (365 nm) increases as the loading of the polymer dye (first polymer) increases. By adding the polymer dye, the dark erosion is reduced. Dark erosion is the non-zero dissolution of resist in the developer in the unexposed areas. However, the sensitivity is improved. By controlling the absorbance, the overhanging pattern profile is also improved.

[0150] Figure 1Ais a plot depicting film loss in the unexposed region of the film (dark erosion) and Figure 1B is a plot depicting sensitivity (E op ) shift as a function of polymer dye (first polymer) loading. CD stands for critical dimension and is measured by pattern size. E th represents the minimum exposure energy that goes through the film during a particular development condition. E op represents the optimum exposure energy that gives the desired pattern size. The goal of this experiment is 15 μm pattern size. In Figure 1A , UFTL stands for unexposed film thickness loss (film thickness loss in the unexposed region).

[0151] Example 2

[0152] This example was conducted to evaluate a photoresist composition containing a polymer dye (first polymer) when subjected to narrowband i-line exposure. The ingredients used in this photoresist composition are shown in Table 3. The structures of the second polymer and the quencher are shown below. The solvent used was propylene glycol methyl ether acetate (PGMEA) and gamma-butyrolactone (GBL) at a weight ratio of 95:5. The first polymer was the same as used in Example 1.

[0153]

[0154] Table 3

[0155]

[0156] All weights in Table 3 are parts by weight per 100 parts of solids in the photoresist composition. Table 4 below shows the test conditions when the photoresist composition was coated on a substrate.

[0157] Table 4

[0158]

[0159]

[0160] As can be seen from Table 3, higher polymer dye (first polymer) loading gives higher sensitivity (lower exposure energy for clear thickness [Eth] and for obtaining target pattern size [Eop]). Without wishing to be bound by theory, the addition of the first polymer to the photoresist composition affects sensitivity through its absorbance capacity. Figure 2 is a plot showing that the addition of the first polymer (containing an anthracene substituent) increases the absorbance of the photoresist at i-line wavelength (365 nm).

[0161] Compared to the second polymer, a higher weight average molecular weight (M w= 15,500 g / mole), the first polymer used a lower weight average molecular weight (M w = 8900 g / mole) was thought to produce a greater amount of dark erosion, but this did not occur. The addition of the first polymer also produced lower film loss (dark erosion), which resulted in a lower dissolution rate of the photoresist composition.

[0162] The sidewall angle decreased as the loading of the first polymer in the photoresist composition increased compared to a comparative photoresist composition that did not contain an anthracene substituent in the polymer. The effect of the ratio of tBOC-4HP to tetrabutylammonium hydroxide base quencher was weak and did not show a significant effect on performance.

[0163] Example 3

[0164] This example was performed to determine the effect of the first polymer (containing an anthracene pendant group) on improving sensitivity and overhang pattern profile. The PAG used was NHNI-PFBS, the first polymer was Polymer Dye-A shown below, and the second polymer was one of Polymer B, Polymer C, or Polymer E, the structures of which are shown below.

[0165]

[0166] The mole percent of each repeat unit in each second polymer is shown above. The photoresist compositions are shown in Tables 5, 6, and 7. The first polymer was Polymer Dye-A (see below) with a weight average molecular weight of 9,800 g / mole.

[0167]

[0168] Table 5 details the photoresists, while Tables 6 and 7 detail the photoresist compositions and some results.

[0169]

[0170] Table 6

[0171]

[0172] Table 7

[0173]

[0174]

[0175] As can be seen from Tables 6 and 7, the first polymer containing an anthracene pendant group imparts higher sensitivity to the photoresist composition. The photoresist composition is effective with i-line radiation (365 nm) even when a PAG other than NHNI-TF is used. As can be seen in Tables 6 and 7, an improvement in the side wall angle (lower side wall angle) is observed when the first polymer is added to the formulation.

[0176] Example 4

[0177] This example demonstrates the effect of using a photoresist composition containing an acetal-protected polyhydroxystyrene as the acid-labile polymer. The photoresist composition also contains the first polymer (polymeric dye) detailed above. Table 9 details the photoresist composition. The second polymer contains an acetal-protected polyhydroxystyrene as the acid-labile polymer and is shown below as Polymer F, which has a weight average molecular weight of 22,000 g / mole.

[0178]

[0179] Table 9 shows the process conditions and Table 10 shows various photoresist compositions containing the first polymer (Polymeric Dye A) and the second polymer (Polymer F). All weights in Table 10 are parts by weight based on total solids content.

[0180] Table 9

[0181]

[0182] Table 10

[0183]

[0184]

[0185] By using a photoresist composition containing a first polymer (containing a polymeric dye) and a second polymer (acetal-protected polyhydroxystyrene), higher sensitivity and improved side wall angles are obtained.

Claims

1. A method for forming a pattern, the method comprising: Apply a photoresist composition layer onto the substrate. The photoresist composition layer is exposed to i-ray radiation in a patterned manner; as well as The exposed photoresist composition layer is developed to provide a photoresist relief image. The photoresist composition layer is applied in a single application by spin coating to a thickness of 1 to 50 micrometers; The photoresist composition comprises: Nonionic photoacid generator; Solvent; A first polymer, comprising a first polymerization unit of formula (1), a second polymerization unit of formula (2), and a third polymerization unit of formula (3): Where a is an integer from 1 to 5 and Z 3 Z and R5 are hydrogen atoms, and Z and R5 are independently selected from hydrogen atoms, C1-C4 alkyl, C1-C4 fluoroalkyl or cyano groups; Z1 is a non-hydrogen substituent containing an acid-labile group, the cleavage of which forms a carboxylic acid on the polymer; L is a substituted or unsubstituted C1-C4 alkylene group; Ar1 ​​is a substituted or unsubstituted anthracene group; wherein, based on the total solids of the photoresist composition, the first polymer is present in the photoresist composition in an amount of 0.1% to 10% by weight; as well as The second polymer comprises the first polymer unit of formula (4): Where b is an integer from 1 to 5 and Z 4 It is hydrogen or an alkyl group having 1 to 5 carbon atoms; and a second polymeric unit comprising a monomer containing an acid-indestabilized group; and wherein the second polymer does not contain polymeric units of formula (3), and is present in the photoresist composition in an amount of 10% to 99% by weight based on the total solids of the photoresist composition.

2. The method according to claim 1, wherein, The acid-unstable group of the second polymer unit in formula (2) is a tertiary ester group or an acetal group.

3. The method according to claim 1, wherein, The third polymerization unit of the first polymer is shown in equation (3a): Each R 4 It is selected from hydrogen, halogen, substituted or unsubstituted alkyl having 1 to 12 carbon atoms; substituted or unsubstituted alkoxy having 1 to 12 carbon atoms; substituted or unsubstituted alkenyl having 2 to 12 carbon atoms; substituted or unsubstituted alkynyl having 2 to 12 carbon atoms; substituted or unsubstituted alkylthio having 1 to 12 carbon atoms; cyano; nitro; amino; or hydroxyl; m is an integer from 0 to 9, and wherein R5 is selected from hydrogen, C1-C4 alkyl, C1-C4 fluoroalkyl and cyano; and wherein L is a divalent linking group.

4. The method according to claim 3, wherein, The first polymer unit of formula (1) comprises polyhydroxystyrene, and the second polymer unit of formula (2) comprises a tertiary alkyl ester.

5. The method according to claim 1, wherein, The second polymer has a higher average molecular weight than the first polymer, and wherein the second polymer has a weight-average molecular weight of 5,000 g / mol to 50,000 g / mol.

6. The method according to claim 1, wherein, The first polymer comprises polyhydroxystyrene, a polymer derived from an olefinically unsaturated acrylate having an acid-insecure group, and a polymer having the following structure: Where R 5 It is hydrogen.

7. The method according to claim 1, wherein, The first polymer has the structure of formula (4): Wherein, based on the total molar number of the copolymer, l is 40 mol% to 75 mol%, m is 8 mol% to 16 mol%, and n is 5 mol% to 30 mol%; and wherein the weight-average molecular weight of the first polymer is 5,000 g / mol to 15,000 g / mol.

8. The method according to claim 1, wherein, The second polymer is a copolymer having a structure of formula (8), (9), (10), (11), or (12): In equation (8), o is 40 mol% to 90 mol% and p is 10 mol% to 60 mol%. as well as In formulas (9) to (12), o is 50 mol% to 85 mol%, p is 5 mol% to 30 mol%, and q is 10 mol% to 25 mol%; and all of the molar percentages are based on the total molar content of the second polymer.

9. The method according to claim 1, wherein, The photoacid generator has the structure shown in formula (13): In equation (13), R 4 It is a substituted or unsubstituted straight or branched chain C1 to C2. 14 Alkyl group, substituted heterocyclic group, or halogen atom; and wherein R 5 It 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; and x is an integer from 0 to 6.

10. The method according to claim 1, wherein, The photoresist composition further comprises an alkaline quencher, wherein the alkaline quencher is selected from N,N-diethyldodecylamide, 2,8-dimethyl-6H,12H-5,11-bridged methylenedibenzo[b,f][1,5]diazopentane and 1,1-dimethylethyl 4-hydroxypiperidine-1-carboxylate.

11. The method according to claim 1, wherein, The acid-unstable groups of the second polymer are tertiary alkyl ester groups or acetal groups.

12. The method according to claim 1, wherein, The monomer containing the acid-unstable group of the second polymer has the structure of formula (7): In equation (7), R b It is hydrogen, fluorine, substituted or unsubstituted C 1-5 Alkyl, or substituted or unsubstituted C 1-5 Fluoroalkyl; each A is independently a halogen, hydroxyl, carboxylic acid or ester, thiol, straight-chain or branched C. 1-20 alkyl, monocyclic or polycyclic C 3-20 Cycloalkyl, monocyclic or polycyclic C 3-20 Fluorocycloalkenyl, monocyclic or polycyclic C 3-20 Heterocyclic alkyl, monocyclic or polycyclic C 6-20 aryl, or monocyclic or polycyclic C 4-20 The heteroaryl groups, each of which is substituted or unsubstituted; and m is independently an integer from 0 to 4; In equation (7), R 11 R 10 and R 8 Each is independently a hydrogen, straight-chain or branched C 1-20 Alkyl, straight-chain or branched C 1-20 Heteroalkyl, monocyclic or polycyclic C 3-20 Cycloalkyl, monocyclic or polycyclic C 3-20 Heterocyclic alkyl, monocyclic or polycyclic C 6-20 Aryl, C 7-20 aryloxyalkyl, or monocyclic or polycyclic C 4-20 Heteroaryl groups, each of which is substituted or unsubstituted, and wherein R 11 R 10 and R 8 Any two of them together can form a ring; In equation (7), R 7 It is a hydrogen, substituted or unsubstituted straight-chain or branched C 1-20 Alkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Cycloalkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Heterocyclic alkyl, substituted or unsubstituted C 6-14 aryl, substituted or unsubstituted C 3-14 heteroaryl, substituted or unsubstituted C 7-18 arylalkyl, substituted or unsubstituted C 4-18 Heteroarylalkyl, or substituted or unsubstituted C 1-12 Heteroalkyl; and wherein in formula (7), R 9 It is a hydrogen, substituted or unsubstituted straight-chain or branched C 1-20 Alkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Cycloalkyl, substituted or unsubstituted monocyclic or polycyclic C 3-20 Heterocyclic alkyl, substituted or unsubstituted C 6-14 aryl, substituted or unsubstituted C 3-14 heteroaryl, substituted or unsubstituted C 7-18 arylalkyl, substituted or unsubstituted C 4-18 Heteroarylalkyl, or substituted or unsubstituted C 1-12 Heteroalkyl; and wherein R 7 and R 9 They can be combined to form a ring, and R 7 R 9 Any one of them can be used with R 8 R 10 or R 11 Any one of them can be combined to form a ring.

13. The method according to claim 10, wherein, The acid-indestabilized group of the second polymer is a tertiary alkyl ester, and the second polymer also contains a third polymer unit of a monomer containing an acetal group.

14. The method according to claim 1, wherein, The solvent is an organic solvent, and the substrate contains a metal layer.

15. The method according to claim 14, wherein, The photoresist composition layer is disposed on the metal layer, and the method further includes immersing the metal layer in a metal plating solution and depositing metal on the metal layer in the exposed portion of the photoresist composition.

16. The method according to claim 1, wherein, L is an unsubstituted C1-C4 alkylene group.

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