CN117826534A - Method for forming a semiconductor device - Google Patents

Abstract

Methods for forming semiconductor devices are provided. The method includes the step of forming a coating layer on a substrate, the coating layer comprising a switchable polymer comprising a polymer backbone and pendant groups attached to the polymer backbone, and an acid generator. The pendant groups include acid labile groups and crosslinking groups. A baking process is then performed to cause crosslinking of the crosslinking groups to form a crosslinked coating layer. Next, a photoresist layer is deposited onto the crosslinked coating layer. After selectively exposing the photoresist layer and the crosslinked coating layer to patterning radiation, developing the selectively exposed photoresist layer and the crosslinked coating layer to form an open pattern on the photoresist layer and the crosslinked coating layer.

Description

Method for forming a semiconductor device

Technical Field

The present disclosure relates to a method for forming a semiconductor device.

Background Art

The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced multiple generations of ICs, each with smaller and more complex circuits than the previous generation. During the evolution of ICs, functional density (i.e., the number of interconnected devices per chip area) has generally increased, while geometry size (i.e., the smallest component (or line) that can be produced using a manufacturing process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and reducing associated costs. This scaling down also increases the complexity of processing and manufacturing ICs.

Summary of the invention

According to some embodiments of the present disclosure, a method for forming a semiconductor device includes the following steps. A coating layer is formed above a substrate. The coating layer includes a switchable polymer and an acid generator. The switchable polymer includes a polymer backbone and a plurality of side groups connected to the polymer backbone, wherein the side groups include a plurality of acid-labile groups and a plurality of cross-linking groups. A baking process is performed to cause the cross-linking groups to undergo a cross-linking reaction to form a cross-linked coating layer. A photoresist layer is deposited above the cross-linked coating layer. The photoresist layer and the cross-linked coating layer are selectively exposed to patterned radiation. The selectively exposed photoresist layer and the cross-linked coating layer are developed to form a pattern of a plurality of openings in the photoresist layer and the cross-linked coating layer.

According to some embodiments of the present disclosure, a method for forming a semiconductor device includes the following steps. A photoresist layer comprising an organic metal compound is deposited onto a substrate. A coating layer is formed over the photoresist layer, the coating layer comprising a switchable polymer, an acid generator, and a quencher. The switchable polymer comprises a polymer backbone and a plurality of pendant acid-labile groups and a plurality of cross-linking groups connected to the polymer backbone. The coating layer is heated at a cross-linking temperature of the cross-linking groups to form a cross-linked coating layer. The photoresist layer and the cross-linked coating layer are selectively exposed to patterned radiation. The selectively exposed photoresist layer and the cross-linked coating layer are developed to form a patterned cross-linked coating layer and a patterned photoresist layer.

According to some embodiments of the present disclosure, a method for forming a semiconductor device includes the following steps. A coating composition is applied to a substrate to form a coating layer, the coating composition comprising a switchable polymer, an acid generator and a solvent. The switchable polymer has a polymer backbone and multiple side groups including one or more acid-labile groups, one or more cross-linking groups and one or more optional floating groups connected to the polymer backbone. The substrate and the coating layer are heated to a temperature at which one or more cross-linking groups react to cross-link the switchable polymer, thereby forming a cross-linked coating layer. A photoresist layer is formed above the cross-linked coating layer. The photoresist layer and the cross-linked coating layer are exposed to radiation through a photomask. Multiple unexposed areas of the photoresist layer and the cross-linked coating layer are removed by a developer to form a patterned photoresist layer and a patterned cross-linked coating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects of the present disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various features are not drawn to scale. In fact, the sizes of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a flow chart of a method for manufacturing a semiconductor device according to some embodiments;

2A to 2F are cross-sectional views of a semiconductor device manufactured using the method of FIG. 1 according to some embodiments;

FIG3 shows an exemplary switchable polymer in a coating layer according to some embodiments;

FIG. 4A illustrates an exemplary organometallic compound according to some embodiments;

FIG. 4B shows an exemplary reaction of an organometallic compound in the presence of water according to some embodiments;

FIG5 shows an exemplary reaction of an organometallic compound according to some embodiments;

FIG6A shows an exemplary cleavage reaction of an acid-labile group of a switchable polymer according to some embodiments;

FIG6B shows an exemplary condensation reaction between an organometallic compound in a photoresist layer and a deprotected switchable polymer in a coating layer according to some embodiments;

7 is a flow chart of a method for manufacturing a semiconductor device according to some embodiments;

8A to 8E are cross-sectional views of a semiconductor device manufactured using the method of FIG. 7 according to some embodiments.

【Explanation of symbols】

100, 700: Method

102, 104, 106, 108, 110, 112, 702, 704, 706, 708, 710, 712: Operation

200:Semiconductor devices

202: Substrate

210: coating layer

210a: Floating area

212: Cross-linked coating layer

212a: Cross-linked floating area

212e: Exposure Area

212u: Unexposed area

212p: Patterned cross-linked coating

214: first baking process, baking or heating process, baking process

220: Photoresist layer

220e: Exposure area

220u: Unexposed area

220p: Patterned photoresist layer

230: Radiation

240: Photomask

242: District 1

244: District 2

250: Opening

260: Recess

301:Polymer

302: Switchable polymer

310: polymer main chain

312: Acid-labile group

314: Cross-linking group

316: floating group

320: Acid Generator

330: Quencher

402:Organometallic compounds

404: Hydroxyl compounds

406:Organometallic polymers

M: Core

M+: Metalcore

L: Ligand

DETAILED DESCRIPTION

The following disclosure provides many different embodiments or examples for realizing the different features of the provided subject matter. Specific examples of components, values, operations, materials, arrangements or the like are described below to simplify the disclosure. Of course, these examples are only illustrative and are not intended to be restrictive. Other components, values, operations, materials, arrangements and the like are considered. For example, forming a first feature above or on a second feature in the following description may include an embodiment in which the first feature and the second feature are formed by direct contact, and may also include an embodiment in which additional features may be formed between the first feature and the second feature so that the first feature and the second feature may not be directly contacted. In addition, the disclosure may repeat component symbols and/or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself specify the relationship between the various embodiments and/or configurations discussed.

Additionally, spatially relative terms, such as "below," "beneath," "below," "above," "upper," and the like, may be used herein for ease of description to describe the relationship of one part or feature to another part or features, as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The system may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should likewise be interpreted accordingly.

When describing the compounds, compositions, methods and processes of the present disclosure, the following terms have the following meanings unless otherwise indicated.

As described herein, the compounds disclosed herein may be optionally substituted with one or more substituents, such as described generally below, or as exemplified by specific classes, subclasses, and materials of the present disclosure. It should be understood that the phrase "optionally substituted" can be used interchangeably with the phrase "substituted or unsubstituted". In general, the term "substituted", whether preceded by the term "optionally", refers to the replacement of one or more hydrogen radicals in a given structure with a radical of a specified substituent. Unless otherwise specified, an optionally substituted group may have a substituent at each substitutable position of the group. When more than one position in a given structure is substituted with more than one substituent selected from a specified group, the substituent may be the same or different at each position.

"Amine" refers to a _-NH2 group.

"Carboxy" refers to a _-CO2H group.

"Carbonyl" refers to a -C=O group.

"Hydroxy" or "hydroxyl" refers to an -OH group.

"Oxo" refers to a =0 substituent.

"Nitro" refers to the _-NO2 radical.

"Alkyl" refers to a straight or branched hydrocarbon group consisting only of carbon atoms and hydrogen atoms, which is saturated or unsaturated (i.e., contains one or more double bonds and/or triple bonds), has one to twelve carbon atoms (C1-C12 alkyl), preferably one to eight carbon atoms (C1-C8 alkyl) or one to six carbon atoms (C1-C6 alkyl), and which is attached to the rest of the molecule by a single bond, such as methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, n-pentyl, 1,1-dimethylethyl (tertiary butyl), 3-methylhexyl, 2-methylhexyl, vinyl, prop-1-enyl, but-1-enyl, pent-1-enyl, pent-1,4-dienyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl and the like. Unless otherwise specifically stated in the specification, the alkyl group may be optionally substituted.

"Alkylene" or "alkylene chain" refers to a straight or branched divalent hydrocarbon chain consisting only of carbon and hydrogen that connects the rest of the molecule to a substituent, the straight or branched divalent hydrocarbon chain being saturated or unsaturated (i.e., containing one or more double bonds and/or triple bonds) and having one to twelve carbon atoms, such as methylene, ethylene, propylene, n-butylene, vinylene, propenylene, n-butenylene, propynylene, n-butynylene, and the like. The alkylene chain is connected to the rest of the molecule and to the substituent via a single bond or a double bond. The points of attachment of the alkylene chain to the rest of the molecule and to the substituent can be through one carbon or any two carbons within the chain. Unless otherwise specifically stated in the specification, the alkylene chain may be substituted as appropriate.

"Alkoxy" refers to a radical of the formula -OR _a , wherein _Ra is an alkyl radical as defined above containing from one to twelve carbon atoms. Unless stated otherwise specifically in the specification, an alkoxy radical may be optionally substituted.

"Alkylamino" refers to a _radical of the formula _-NHRa or _-NRaRa , wherein each _Ra is independently an alkyl radical as defined above containing from one to twelve carbon atoms. Unless stated otherwise specifically in the specification, an alkylamino radical may be optionally substituted.

"Amide" refers to _{a -NRaRb} radical, where _Ra and _Rb are independently H, alkyl or aryl. Unless stated otherwise specifically in the specification, an amide group may be optionally substituted.

"Aryl" refers to a hydrocarbon ring system radical containing hydrogen, 6 to 18 carbon atoms and at least one aromatic ring. For the purposes of this disclosure, an aryl group may be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which may include fused or bridged ring systems. Aryl groups include, but are not limited to, those derived from aceanthrylene, acenaphthylene, acephenanthrylene, allium, azulene, benzene, The term "aryl" or the prefix "ar-" (such as in "aralkyl") is intended to include optionally substituted aryl groups, unless otherwise specifically stated in the specification.

"Cycloalkyl" or "carbocycle" refers to a stable, aromatic monocyclic or polycyclic hydrocarbon radical consisting solely of carbon and hydrogen atoms, which may include a fused or bridged ring system, having three to fifteen carbon atoms, preferably three to ten carbon atoms, and which is saturated or unsaturated and connected to the rest of the molecule by a single bond. Monocyclic cycloalkyls include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Polycyclic cycloalkyls include, for example, adamantyl, norbornyl, decahydronaphthyl, 7,7-dimethyl-bicyclo[2.2.1]heptanyl, and the like. Unless otherwise specifically stated in the specification, cycloalkyls may be optionally substituted.

"Halo" or "halogen" refers to bromo, chloro, fluoro and iodo.

"Haloalkyl" refers to an alkyl group as defined above substituted with one or more halo groups as defined above, such as trifluoromethyl, difluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 1,2-difluoroethyl, 3-bromo-2-fluoropropyl, 1,2-dibromoethyl and the like. Unless otherwise specifically stated in the specification, a haloalkyl group may be optionally substituted.

"Heterocyclyl" or "heterocycle" refers to a stable 3- to 18-membered non-aromatic ring group consisting of 2 to 12 carbon atoms and 1 to 6 heteroatoms selected from nitrogen, oxygen and sulfur. Unless otherwise specifically stated in the specification, the heterocyclyl may be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which may include a fused or bridged ring system; and the nitrogen, carbon or sulfur atom in the heterocyclyl may be optionally oxidized; the nitrogen atom may be optionally quaternized; and the heterocyclyl may be partially or fully saturated. Examples of such heterocyclic groups include, but are not limited to, dioxolanyl, thienyl[1,3]dithiocyclohexyl, decahydroisoquinolinyl, imidazolinyl, imidazolidinyl, isothiazolyl, isoxazolidinyl, morpholinyl, octahydroindolyl, octahydroisoindolyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2-oxopyrrolidinyl, oxazolidinyl, piperidinyl, piperazinyl, 4-piperidonyl, pyrrolidinyl, pyrazolidinyl, quinuclidinyl, tetrahydrothiazolyl, tetrahydrofuranyl, trithianyl, tetrahydropyranyl, thiomorpholinyl, thiomorpholinyl, 1-oxo-thiomorpholinyl and 1,1-dioxo-thiomorpholinyl. Unless otherwise specifically stated in the specification, the heterocyclic group may be optionally substituted.

"N-heterocyclyl" refers to a heterocyclyl as defined above containing at least one nitrogen and wherein the point of attachment of the heterocyclyl to the rest of the molecule is through the nitrogen atom in the heterocyclyl. Unless stated otherwise specifically in the specification, an N-heterocyclyl group may be optionally substituted.

"Heterocyclylalkyl" refers to a radical of _the formula _-RbRe , wherein _Rb is an alkylene chain as defined above and _Re is a heterocyclyl radical as defined above, and if the heterocyclyl radical is a nitrogen-containing heterocyclyl radical, the heterocyclyl radical may be attached to the alkyl radical at the nitrogen atom. Unless otherwise specifically stated in the specification, the heterocyclylalkyl radical may be optionally substituted.

"Heteroaryl" refers to a 5- to 14-membered ring system radical comprising hydrogen atoms, one to thirteen carbon atoms, one to six heteroatoms selected from nitrogen, oxygen and sulfur, and at least one aromatic ring. For the purposes of this disclosure, a heteroaryl group may be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which may include a fused or bridged ring system; and the nitrogen, carbon or sulfur atoms in the heteroaryl group may be optionally oxidized; the nitrogen atom may be optionally quaternized. Examples include, but are not limited to, azobenzene, acridinyl, benzimidazolyl, benzothiazolyl, benzindolyl, benzodioxolyl, benzofuranyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, benzo[b][1,4]dioxolyl, 1,4-benzodioxanyl, benzonaphthofuranyl, benzoxazolyl, benzodioxolyl, benzodioxinyl, benzopyranyl, benzopyranonyl, benzofuranyl, benzofuranonyl, benzothiophenyl (benzophenylthio), benzotriazolyl, benzo[4,6]imidazo[1,2-a]pyridinyl, carbazolyl, cinnolinyl, dibenzofuranyl, dibenzophenylthio, furanyl, furanonyl, isothiazolyl, imidazolyl , indazolyl, indolyl, indazolyl, isoindolyl, indolinyl, isoindolyl, isoquinolinyl, indolizinyl, isoxazolyl, naphthyridinyl, oxadiazolyl, 2-oxazapyridine, oxazolyl, oxiranyl, 1-pyridinyl oxide, 1-pyrimidinyl oxide, 1-pyrazinyl oxide, 1-pyridazinyl oxide, 1-phenyl-1H-pyrrolyl, phenazinyl, phenathiazinyl, phenoxazinyl, oxazinyl, pteridinyl, purinyl, pyrrolyl, pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinazolinyl, quinoxalinyl, quinolinyl, quinuclidinyl, isoquinolinyl, tetrahydroquinolinyl, thiazolyl, thiadiazolyl, triazolyl, tetrazolyl, triazinyl and thiophenyl (i.e., thienyl). Unless otherwise specifically stated in the specification, the heteroaryl group may be optionally substituted.

"N-heteroaryl" refers to a heteroaryl group as defined above containing at least one nitrogen and wherein the point of attachment of the heteroaryl group to the rest of the molecule is through the nitrogen atom in the heteroaryl group. Unless stated otherwise specifically in the specification, an N-heteroaryl group may be optionally substituted.

"Heteroaralkyl" refers to a radical of _the formula _-RbRf , wherein _Rb is an alkylene chain as defined above and _Rf is a heteroaryl group as defined above. Unless stated otherwise specifically in the specification, a heteroaralkyl radical may be optionally substituted.

"Hydroxyalkyl" refers to an alkyl group containing at least one hydroxy substituent. The one or more -OH substituents may be located on a primary, secondary or tertiary carbon atom. Unless otherwise specifically stated in the specification, a hydroxyalkyl group may be optionally substituted.

"Hydroxyalkyl ether" refers to an alkyl ether group containing at least one hydroxy substituent. The one or more -OH substituents may be located on a primary, secondary or tertiary carbon atom. Unless otherwise specifically stated in the specification, a hydroxyalkyl ether group may be optionally substituted.

"Sulfonate" refers to a -OS(O) _{2Ra radical} , where _Ra is alkyl or aryl. Unless stated otherwise specifically in the specification, a sulfonate group may be optionally substituted.

As used herein, the term "substituted" means any of the above groups (i.e., alkyl, alkylene, alkoxy, alkylamino, amide, aryl, cycloalkyl, etc.) in which at least one hydrogen atom is replaced by a bond to a non-hydrogen atom, such as, but not limited to, halogen atoms such as F, Cl, Br, and I; oxygen atoms in groups such as hydroxyl, alkoxy, and ester groups; sulfur atoms in groups such as thiol, thioalkyl, sulfone, sulfonyl, and sulfoxide groups; nitrogen atoms in groups such as amine, amide, alkylamine, dialkylamine, arylamine, alkarylamine, diarylamine, N-oxide, imide, and enamine; silicon atoms in groups such as trialkylsilyl, dialkylarylsilyl, alkyldiarylsilyl, and triarylsilyl; and other heteroatoms in various other groups. "Substituted" also means any of the above groups in which one or more hydrogen atoms are replaced by a higher order bond (e.g., a double bond or a triple bond) to a heteroatom, such as oxygen in pendant oxy, carbonyl, carboxyl, and ester groups; and nitrogen in _groups such as _imines , oximes, hydrazones, and nitriles. For example, "substituted" includes any of the above groups in which one or more hydrogen atoms are _replaced by _-NRgRh , _-NRgC (= _O ) _Rh , _-NRgC (=O) _NRgRh , _{-NRgC (} = _{O )} ORh, _-NRgSO2Rh , _{-OC (} = _{O )} NRgRh, _-ORg , -SRg, _{-SORg , -SO2Rg} , _-OSO2Rg , _-SO2ORg , = _{NSO2Rg , and -SO2NRgRh} . "Substituted" also means any of the above groups in which one or more hydrogen atoms are replaced by -C(=O) _Rg , -C(=O _{) ORg} , -C(=O) _NRgRh , _-CH2SO2Rg , _-CH2SO2NRgRh . In the above, _Rg and _Rh are the same or different and are independently _hydrogen , alkyl, alkoxy _{, alkylamino} , thioalkyl, _aryl , aralkyl, cycloalkyl, cycloalkylalkyl, haloalkyl, heterocyclyl, N _- heterocyclyl, heterocyclylalkyl, heteroaryl, N-heteroaryl and/or heteroarylalkyl. "Substituted" further means any of the above groups in which one or more hydrogen atoms are replaced by a bond to an amine, cyano, hydroxyl, imino, nitro, pendant, thiol, halo, alkyl, alkoxy, alkylamino, thioalkyl, aryl, aralkyl, cycloalkyl, cycloalkylalkyl, haloalkyl, heterocyclyl, N-heterocyclyl, heterocyclylalkyl, heteroaryl, N-heteroaryl and/or heteroarylalkyl. In addition, each of the above substituents may also be substituted with one or more of the above substituents as appropriate.

IC manufacturing uses one or more photolithography processes to transfer geometric patterns onto a film or substrate. The geometric shapes and patterns on the semiconductor form complex structures that enable dopants, electrical properties, and wires to form circuits and achieve technological goals. In the photolithography process, a photoresist is applied as a thin film to a substrate and then exposed to one or more types of radiation or light through a mask. The mask contains transparent and opaque features that define the pattern to be produced in the photoresist layer. The areas of the photoresist exposed to the light passing through the mask are soluble or insoluble in a specific type of solution called a developer. In the case where the exposed areas are soluble, a positive image of the mask is produced in the photoresist, and this type of photoresist is called a positive photoresist. On the other hand, if the unexposed areas are dissolved by the developer, a negative image is produced in the photoresist, and this type of photoresist is called a negative photoresist. The developer removes the more soluble areas, leaving the patterned photoresist in place. The resist pattern is then used as an etch mask in a subsequent etching process to transfer the pattern to the underlying material layer, thereby replicating the mask pattern in the underlying material layer. Alternatively, the resist pattern is then used as an ion implantation mask in a subsequent ion implantation process applied to the underlying material layer, such as an epitaxial semiconductor layer.

Extreme ultraviolet (EUV) lithography that achieves sub-20nm half-pitch resolution is being developed for mass production at the next-generation sub-5nm node. EUV lithography requires high-performance photoresists with high sensitivity to reduce the cost of high-power exposure sources and provide good image resolution.

As feature size decreases to below 40nm pattern pitch, line width resolution is affected. In small pitch and high aspect ratio patterns, it is difficult to remove residual photoresist or scum. In order to improve line width roughness (LWR) in EUV etching operations, a coating layer is formed under a photoresist layer or on top of a photoresist layer according to an embodiment of the present disclosure, the coating layer includes a switchable polymer having a polymer backbone and pendant acid-labile groups and cross-linking groups connected to the polymer backbone. Upon irradiation, the acid-labile groups of the switchable polymer in the exposed areas of the coating layer cleave from the polymer backbone to generate reactive functional groups, which react with the organometallic compound in the photoresist layer to form covalent bonds therebetween. Therefore, the coating layer helps to enhance the collapse window, reduce LWR, and fine-tune the profile shape of the resist pattern. By using a coating layer under or over the photoresist layer, the collapse window can be expanded by about 0.5nm to 2nm, the LWR can be improved by more than 5%, and the resist pattern integrity can be improved by more than 10%. In some embodiments, the coating layer is formed below the photoresist layer and serves as a bottom anti-reflective coating (BARC). In some embodiments, the coating layer is formed on top of the photoresist layer and serves as a top anti-reflective coating (TARC).

FIG. 1 is a flow chart illustrating a method 100 for forming a semiconductor device 200 according to some embodiments of the present disclosure. FIGS. 2A-2F are cross-sectional views of the semiconductor device 200 at various stages of fabrication according to some embodiments of the present disclosure. Intermediate steps of the method 100 are described with reference to the cross-sectional views of the semiconductor device 200 as shown in FIGS. 2A-2F. It should be understood that for additional embodiments of the method, additional steps may be provided before, during, and after the method 100, and some of the steps described below may be replaced or eliminated. It should be further understood that for additional embodiments of the semiconductor device 200, additional features may be added to the semiconductor device 200, and some of the features described below may be replaced or eliminated.

Semiconductor device 200 may be an intermediate structure or a portion thereof during IC manufacturing. An IC may include logic circuits, memory structures, passive components (such as resistors, capacitors, and inductors), and active components such as diodes, field-effect transistors (FETs), metal-oxide semiconductor field effect transistors (MOSFETs), complementary metal-oxide semiconductor (CMOS) transistors, bipolar transistors, high-voltage transistors, high-frequency transistors, fin FETs, other three-dimensional (3D) FETs, and combinations thereof. Semiconductor device 200 may include multiple semiconductor devices (e.g., transistors) that may be interconnected.

1 and 2A, according to some embodiments, method 100 includes operation 102, in which a coating layer 210 is formed over a substrate 202. FIG2A is a cross-sectional view of a semiconductor device 200 after forming a coating layer 210 over a substrate 202, according to some embodiments.

In some embodiments, substrate 202 may be a bulk semiconductor substrate including one or more semiconductor materials. In some embodiments, substrate 202 may include silicon, silicon germanium, carbon-doped silicon (Si:C), silicon germanium carbide, or other suitable semiconductor materials. In some embodiments, substrate 202 is entirely composed of silicon.

In some embodiments, substrate 202 may include one or more epitaxial layers formed on a top surface of a bulk semiconductor substrate. In some embodiments, the one or more epitaxial layers introduce strain into substrate 202 for performance enhancement. For example, the epitaxial layers include a semiconductor material different from the semiconductor material of the bulk semiconductor substrate, such as a silicon germanium layer covering bulk silicon or a silicon layer covering bulk silicon germanium. In some embodiments, the one or more epitaxial layers incorporated into substrate 202 are formed by selective epitaxial growth (such as metal-organic vapor phase epitaxy (MOVPE), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE), liquid phase epitaxy (liquid phase epitaxy, LPE), metal-organic molecular beam epitaxy (MOMBE) or a combination thereof).

In some embodiments, substrate 202 may be a semiconductor-on-insulator (SOI) substrate. In some embodiments, the SOI substrate includes a semiconductor layer, such as a silicon layer formed on an insulator layer. In some embodiments, the insulator layer is a buried oxide (BOX) layer including silicon oxide or silicon germanium oxide. The insulator layer is disposed on a processing substrate such as a silicon substrate. In some embodiments, the SOI substrate is formed using separation implantation oxygen (SIMOX) or other suitable techniques such as wafer bonding and grinding.

In some embodiments, substrate 202 may also include a dielectric substrate such as silicon oxide, silicon nitride, silicon oxynitride, low-k dielectric, silicon carbide, and/or other suitable layers.

In some embodiments, substrate 202 may also include various p-type doped regions and/or n-type doped regions, which are implemented by processes such as ion implantation and/or diffusion. Those doped regions include n-type wells, p-type wells, lightly doped regions (LDDs), and various channel doping profiles, which are used to form various IC devices, such as COMOS transistors, imaging sensors, and/or light emitting diodes (LEDs). Substrate 202 may also include other functional features, such as resistors and/or capacitors formed in and/or on substrate 202.

In some embodiments, substrate 202 may also include various isolation features. Isolation features separate various device regions in substrate 202. Isolation features include different structures formed by using different processing techniques. For example, isolation features may include shallow trench isolation (STI) features. The formation of STI may include etching trenches in substrate 202 and filling the trenches with insulator materials such as silicon oxide, silicon nitride and/or silicon oxynitride. The filled trenches may have a multi-layer structure, such as a thermal oxide liner with silicon nitride filling the trenches. Chemical mechanical polishing (CMP) may be performed to polish away excess insulator material and planarize the top surface of the isolation features.

In some embodiments, the substrate 202 may also include a gate stack formed of a dielectric layer and an electrode layer. The dielectric layer may include an interfacial layer and a high-k dielectric layer deposited by a suitable technique, such as chemical vapor deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD), thermal oxidation, combinations thereof, and/or other suitable techniques. The interfacial layer may include silicon dioxide and the high-k dielectric layer may include LaO, AlO, ZrO, TiO, Ta ₂ O ₅ , Y ₂ O ₃ , SrTiO ₃ , BaTiO ₃ , BaZrO, HfZrO, HfLaO, HfSiO, LaSiO, AlSiO, HfTaO, HfTiO, (Ba,Sr)TiO ₃ (BST), Al ₂ O ₃ , Si ₃ N ₄ , SiON, and/or other suitable materials. The electrode layer may include a single layer or a multilayer structure, such as a metal layer having a work function for enhancing device performance (work function metal layer), a liner, a wetting layer, an adhesion layer, and various combinations of a conductive layer of a metal, a metal alloy, or a metal silicide. The electrode layer may include Ti, Ag, Al, TiAlN, TaC, TaCN, TaSiN, Mn, Zr, TiN, TaN, Ru, Mo, Al, WN, Cu, W, any suitable material, and/or combinations thereof.

In some embodiments, the substrate 202 may also include multiple inter-level dielectric (ILD) layers and conductive features integrated to form an interconnect structure, which is used to couple various p-type and n-type doped regions and other functional features (such as gate electrodes) to form a functional integrated circuit. In one example, the substrate 202 may include a portion of an interconnect structure, and the interconnect structure may include a multi-layer interconnect (MLI) structure and an ILD layer integrated with the MLI structure, providing electrical wiring to couple various devices in the substrate 202 to input/output power and signals. The interconnect structure includes various metal lines, contacts, and through-hole features (or plug holes). Metal lines provide horizontal electrical wiring. Contacts provide vertical connections between the silicon substrate and the metal lines, and through-hole features provide vertical connections between metal lines in different metal layers.

In some embodiments, substrate 202 includes a dielectric layer. In some embodiments, the dielectric layer includes silicon oxide, silicon nitride, or silicon oxynitride. In some other embodiments, the dielectric material includes a metal oxide such as titanium oxide or a metal nitride such as titanium nitride.

The coating layer 210 is disposed on the substrate 202. In some embodiments, the coating layer 210 improves the adhesion of the photoresist layer to the substrate 202. In some embodiments, the coating layer 210 acts as a bottom anti-reflective coating (BARC). The BARC absorbs radiation passing through the photoresist layer, thereby preventing the radiation from reflecting from the substrate 202 and exposing unintended portions of the photoresist layer. Therefore, the BARC improves the line width roughness and line edge roughness of the photoresist pattern.

In some embodiments and as shown in FIG. 3 , the coating layer 210 may include a switchable polymer 302 , an acid generator 320 , and a quencher 330 .

The switchable polymer 302 has a polymer backbone 310 and a plurality of side groups (e.g., groups 312, 314, and 316) connected to the polymer backbone 310. In some embodiments, the polymer backbone 310 is an organic polymer or an inorganic polymer. In some embodiments, the polymer backbone 310 (i.e., the polymer main chain) is formed by one or more monomers selected from the group consisting of acrylates, acrylic acid, siloxanes, hydroxystyrenes, methacrylates, vinyl esters, maleates, methacrylonitrile, and methacrylamide.

In some embodiments, the functional groups attached to the polymer backbone 310 may include an acid labile group 312, a crosslinking group 314, and a floating group 316. The floating group 316 is optional and may be omitted in some embodiments. In some embodiments, additional functional groups may be bonded to the polymer backbone 310 and/or between the polymer backbone 310 and the functional groups 312, 314, and 316.

Acid labile groups (ALG) 312 are linked to the polymer backbone 310 via linkers ^L1. Acid labile groups 312 undergo an acid-promoted deprotection reaction upon exposure to radiation and/or heat treatment, thereby generating reactive groups on the polymer side chains. In some embodiments, the decomposed acid labile groups 312 are derived from carboxylic acid groups, fluorinated alcohol groups, phenolic alcohol groups, sulfonic acid groups, sulfonamide groups, sulfonimide groups, (alkylsulfonyl)(alkylcarbonyl)methylene groups, (alkylsulfonyl)(alkylcarbonyl)imino groups, bis(alkylcarbonyl)methylene groups, bis(alkylcarbonyl)imino groups, bis(alkylsulfonyl)methylene groups, bis(alkylsulfonyl)imino groups, tris(alkylcarbonyl)methylene groups, tris(alkylsulfonyl)methylene groups, combinations of these groups, or the like. Specific groups for fluorinated alcohol groups include fluorinated hydroxyalkyl groups, such as hexafluoroisopropanol groups in some embodiments. Specific groups for the carboxylic acid group include an acrylic acid group, a methacrylic acid group or the like.

The acid-labile groups 312 are selected to be stable at the crosslinking temperature of the crosslinking groups 314 and the photoresist pre-exposure bake temperature, so that the acid-labile groups 312 do not switch or decompose before exposure to radiation. For example, in the case where the crosslinking temperature is 215° C. and the photoresist pre-exposure bake temperature is 180° C., the acid-labile groups 312 need to be stable at least at 215° C. In some embodiments, the acid-labile groups 312 account for about 10 wt.% to about 70 wt.% of the switchable polymer 302. When the amount of the acid-labile groups 312 is outside the disclosed range, line width roughness and scum reduction may not be improved.

The crosslinking group 314 is connected to the polymer backbone 310 via the linker ^L2. The crosslinking groups 314 on the two polymer chains can react to bond the two polymer chains together, thereby improving the solvent resistance of the coating layer 210, so that the coating layer 210 is not dissolved by the solvent used to form the photoresist layer. The crosslinking group 314 is selected so that the activation energy of the crosslinking group 314 is lower than the activation energy of the acid-labile group 312, so that the crosslinking of the switchable polymer 302 does not cause the reaction or decomposition of the acid-labile group 312. In some embodiments, the crosslinking group 314 accounts for about 30 wt.% to about 70 wt.% of the switchable polymer 302. When the amount of the crosslinking group 314 is outside the disclosed range, the line width roughness and scum reduction may not be improved.

The floating group 316 is connected to the polymer backbone 310 via a linker ^L3 . In some embodiments, ^L3 is not present and the floating group 316 is directly connected to the polymer backbone 310. The floating group 316 helps the switchable polymer 302 float to the upper part of the coating layer 210 during the coating and baking process. In some embodiments, the floating group 316 includes a fluorine-containing functional group. In some embodiments, the floating group 316 is a fluoroalkyl group, such as _-CF3 , _-C2F5 , _{-C3F7 ,} or _-C4F9 . In some embodiments, in the case where the acid-labile group 312 includes a fluoroalkyl group that can float the switchable polymer 302, the floating group 316 is omitted from the polymer structure _. If present, the floating group ₃₁₆ accounts for about 5 wt.% to about 40 wt.% of the switchable polymer 302. When the amount of the floating group 316 is outside the disclosed range, line width roughness and scum reduction may not be improved.

In some examples, the switchable polymer 302 has the following structure (I):

in:

L ¹ , L ² and L ³ are independently at each occurrence a direct bond or a C _1-10 alkylene, C _1-10 heteroalkylene, arylene, heteroarylene or heteroatom linker.

Ra, Rb and Rc are independently hydrogen, C _1-10 alkyl or halogen at each occurrence;

R ^1, at each occurrence, is an acid-labile group;

R ^2, at each occurrence, is a cross-linking group;

R ³ is a floating group at each occurrence;

m and n are independently an integer of 1 or greater; and

p is an integer of 0 or greater.

In some embodiments, Ra, Rb, and Rc are each independently hydrogen or methyl.

In some embodiments, R ¹ has one of the following structures:

In some embodiments, R ² has one of the following structures:

in:

R at each occurrence is hydrogen or C _1-10 alkyl;

q is an integer from 1 to 300; and

w is an integer from 1 to 6.

In some embodiments, R is methyl, ethyl, propyl, isopropyl, n-butyl, and n-pentyl.

R ³ is a CxFy-containing group. CxFy may contain a straight chain or a branched chain. The number of carbon atoms (x) may be one (1) to nine (9). The number of fluorine atoms (y) may be equal to 2x+1 or 3x. In some embodiments, R ³ has one of the following structures:

In some embodiments, L ¹ , L ² and L ³ are independently substituted or unsubstituted, branched or unbranched, cyclic or acyclic groups, and include unsubstituted or halogen (e.g., olefin) substituted saturated 1-9 carbocyclic or acyclic groups, -S-, -P-, -P(O ₂ )-, -C(═O)S-, -C(═O)O-, -O-, -N-, -C(═O)N-, -SO ₂ O-, -SO ₂ S-, -SO-, -SO ₂ -, -C ₆ H ₆ -O-, -C ₆ H ₆ -OC(═O)O-, or ether, keto, ester, or phenylene.

In some embodiments, L ¹ , L ² or L ³ independently has one of the following structures:

Acid generator 320 is dispersed within coating layer 210. Acid generator 320 is selected to have sufficient thermal stability to withstand the high temperatures used in the heating process to which coating layer 210 is subjected during processing (eg, crosslinking crosslinking groups 314 and baking the photoresist).

In some embodiments, the acid generator 320 is a photoacid generator (PAG) that generates an acid when exposed to radiation, such as EUV radiation or electron beam radiation. In some embodiments, the photoacid generator may include a combination of cations and anions. Examples of photoacid generators according to embodiments of the present disclosure include α-(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide (MDT), N-hydroxy-naphthalene dicarboximide (DDSN), benzoin tosylate, tert-butylphenyl-α-(p-toluenesulfonyloxy) acetate and tert-butyl-α-(p-toluenesulfonyloxy) acetate, triarylsulfonium and diaryliodonium hexafluoroantimonates, hexafluoroarsenates, trifluoromethanesulfonates, iodonium perfluorooctanesulfonates, N-camphorsulfonyloxynaphthalene dicarboximide, N-pentafluorophenylsulfonyloxynaphthalene dicarboximide, ionic iodonium, sulfonates (such as diaryliodonium (alkyl or aryl) sulfonates and bis-(di-tert-butylphenyl)iodonium camphenyl sulfonate), perfluoroalkane sulfonates (such as perfluoropentanesulfonate, perfluorooctanesulfonate, perfluoromethanesulfonate), aryl (e.g. phenyl or benzyl) trifluoromethanesulfonates (such as triphenylsulfonium trifluoromethanesulfonate or bis-tert-butylphenyl)iodonium trifluoromethanesulfonate), gallol derivatives (e.g. gallol trimesylate), trifluoromethanesulfonates of hydroxyimides, α,α′-bis-sulfonyl-diazomethane, sulfonates of nitro-substituted benzyl alcohols, naphthoquinone-4-diazide, alkyl disulfones or the like.

In some embodiments, the cation is selected from the group consisting of:

In some embodiments, the anion is selected from the group consisting of:

In some embodiments, the acid generator 320 is a thermal acid generator (TAG) that generates acid when heated. In some embodiments, the thermal acid generator is selected from the group consisting of:

in:

R is H or alkyl; and

n is an integer of 1 to 6.

In some embodiments, the concentration of the acid generator 320 is in the range of about 1 wt.% to about 20 wt.% based on the total weight of the coating composition. In other embodiments, the concentration of the acid generator 320 is in the range of about 10 wt.% to about 15 wt.% based on the total weight of the coating composition. When the concentration of the acid generator 320 is below the disclosed range, sufficient acid may not be generated to improve line width roughness and reduce scum. When the concentration of the acid generator 320 is greater than the disclosed range, there may be no significant improvement or line width roughness and scum may increase.

The quencher 330 is dispersed in the coating layer 210. The quencher 330 neutralizes the excess acid generated by the irradiation operation and the subsequent post-exposure baking operation, thereby inhibiting the diffusion of the generated acid in the coating layer 210. The quencher 330 improves the resist pattern configuration and the stability of the photoresist over time. In some embodiments, the quencher 330 is an amine, such as a secondary lower aliphatic amine, a tertiary lower aliphatic amine, or a similar amine. Specific examples of amines include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine and triethanolamine, alkanolamine, a combination thereof, or a similar amine. In some embodiments, the quencher 330 has one of the following structures:

In some embodiments, the quencher 330 is a photodecomposable base (PDB) that generates a basic moiety in response to radiation. The basic moiety generated by the photodecomposable base reacts with the generated acid, thereby preventing the generated acid from diffusing into the portion of the coating layer 210 that is not exposed to the actinic radiation. In some embodiments, the photodecomposable base may include a combination of cations and anions. In some examples, the photobase generator has the following structure:

in:

R is alkyl, heteroalkyl, cycloalkyl or heterocycloalkyl;

X is a carbonyloxy group (-C(=O)O-);

Y is a linear, branched or cyclic alkyl or aryl group;

Rf is a hydrocarbon group containing a fluorine atom; and

represents an organic cation or a metal cation.

In some embodiments, R is selected from cyclopentyl, cyclohexyl, cycloheptyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl, 2-oxycyclopentyl, 2-oxycyclohexyl, 2-cyclopentyl-2-oxyethyl, 2-cyclohexyl-2-oxyethyl, 2-(4-methylcyclohexyl)-2-oxyethyl, and 4-oxyadamantyl.

In some embodiments, Rf is trifluoromethyl.

In some embodiments, the cation is selected from one of the following structures:

In some embodiments, the anion is selected from one of the following structures:

In some embodiments, the concentration of the quencher 330 is in the range of about 1 wt.% to about 20 wt.% based on the total weight of the coating composition. In other embodiments, the concentration of the quencher 330 is in the range of about 10 wt.% to about 15 wt.% based on the total weight of the coating composition. When the concentration of the quencher 330 is below the disclosed range, there may not be enough base to improve the line width roughness and reduce scum. When the concentration of the quencher 330 is greater than the disclosed range, there may not be a significant improvement or may be a reduction in line width roughness and scum.

In some embodiments, the coating layer 210 may have a thickness in the range of about 2 nm to about 1 nm. In some embodiments, the coating layer 210 has a thickness in the range of about 5 nm to about 500 nm, and in other embodiments, the coating layer 210 has a thickness in the range of about 10 nm to about 200 nm. Coating thicknesses less than the disclosed ranges may not be sufficient to provide adequate photoresist adhesion and anti-reflective properties. Coating thicknesses greater than the disclosed ranges may be unnecessarily thick and may not provide further improvements in resist layer adhesion and scum reduction.

To form the coating layer 210, the individual components of the coating layer 210 including the switchable polymer 302, the acid generator 320, and the quencher 330 are placed in a solvent, and the resulting coating composition is then applied to the top surface of the substrate 202, for example, by spin coating or by CVD, PVD, or ALD. The solvent can be any suitable solvent for dissolving the switchable polymer 302 and the selected coating components, such as the acid generator 320 and the quencher 330. In some embodiments, the solvent is one or more selected from the following: propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), 1-ethoxy-2-propanol (PGEE), γ-butyrolactone (GBL), cyclohexanone (CHN), ethyl lactate (EL), methanol, ethanol, propanol, n-butanol, acetone, dimethylformamide (DMF), isopropyl alcohol (IPA), tetrahydrofuran (THF), methyl isobutyl carbinol (MIBC), n-butyl acetate (nBA), and 2-heptanone (MAK).

In some embodiments, the coating layer 210 may include a floating region 210a along the top surface of the coating layer 210. In some embodiments, the floating region 210a may include the acid-labile groups 312 and the floating groups 316 (if present). The floating region 210a is formed due to the acid-labile groups 312 and the floating groups 316 moving to the top of the coating layer 210 when the coating layer 210 is applied, for example, by spin coating. This movement is caused because the acid-labile groups 312 and the floating groups 316 have high surface energy due to the addition of fluorine atoms. This high surface energy, combined with the low interaction between the fluorine atoms and other atoms in the coating layer 210, simultaneously causes the acid-labile groups 312 and the floating groups 316 to move toward the top surface of the coating layer 210.

In embodiments where a float region 210a is formed, the float region 210a will have a higher concentration of acid-labile groups 312 than the remainder of the coating layer 210, such as between about 0.01% and about 10%, such as about 2%, while the remainder of the coating layer 210 (outside the float region 210a) will have a concentration of acid-labile groups 312 no greater than about 5%. In some embodiments, the float region 210a will have a concentration between about 0.01% and about 10%, such as about 2%. About Between, such as about However, these dimensions and concentrations may vary and are intended to be illustrative only, and any benefits may be obtained from suitable concentrations other than those listed herein.

1 and 2B, according to some embodiments, method 100 proceeds to operation 104, where coating layer 210 is cross-linked to form cross-linked coating layer 212. FIG2B is a cross-sectional view of semiconductor device 200 after forming cross-linked coating layer 212 according to some embodiments.

In some embodiments, a first baking process 214 is performed to remove residual solvent from the coating layer 210 and cause the crosslinking groups 314 to crosslink, thereby forming a crosslinked coating layer 212. In some embodiments, the crosslinked coating layer 212 includes a crosslinked floating area 212a along the top surface of the crosslinked coating layer 212. The first baking process 214 is performed for a period of time at a temperature sufficient to cause the crosslinking groups 314 to react with each other and bond the individual polymers 301 into a polymer network; but does not cause the acid-labile groups 312 to decompose. In some embodiments, the baking or heating process 214 is performed at a temperature ranging from about 40°C to about 300°C. In certain embodiments, the first baking process 214 is performed at a temperature of about 80°C to about 200°C for about 20 seconds to about 3 minutes. In other embodiments, the baking process 214 is performed at a temperature of about 100°C to about 250°C for about 10 seconds to about 2 minutes.

1 and 2C, according to some embodiments, the method proceeds to operation 106 where a photoresist layer 220 is formed over the cross-linked coating layer 212. FIG2C is a cross-sectional view of the semiconductor device 200 after forming the photoresist layer 220 over the cross-linked coating layer 212 according to some embodiments.

Photoresist layer 220 is a photosensitive layer patterned by exposure to radiation. Generally, the chemical properties of the photoresist area irradiated by the incident radiation vary in a manner depending on the type of photoresist used. Photoresist layer 220 includes a positive resist or a negative resist. A positive resist refers to a photoresist material that becomes soluble in a developer when exposed to radiation (such as UV light), while the unexposed (or less exposed) photoresist area is insoluble in the developer. On the other hand, a negative resist refers to a photoresist material that becomes insoluble in a developer when exposed to radiation, while the unexposed (or less exposed) photoresist area is soluble in the developer. The negative resist area that becomes insoluble when exposed to radiation may become insoluble due to the cross-linking reaction caused by exposure to radiation.

In some embodiments, the photoresist layer 220 includes a high-sensitivity photoresist composition. In some embodiments, the high-sensitivity photoresist composition includes a metal that has a high absorption to EUV radiation.

In some embodiments, the photoresist layer 220 may include an organometallic compound including a metal core coordinated with a plurality of organic ligands. In some embodiments and as shown in FIG. 4A , the organometallic compound has the following formula:

M _a L _b X _c ，

in:

M is at least one of tin (Sn), bismuth (Bi), antimony (Sb), indium (In), tellurium (Te), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), cobalt (Co), molybdenum (Mo), tungsten (W), aluminum (Al), arsenic (As), yttrium (Y), lanthanum (La), cerium (Ce), or lutetium (Lu);

L is independently substituted or unsubstituted alkyl, alkenyl, cycloalkyl, cycloheteroalkyl, aralkyl, aryl or heteroaryl;

X is independently a hydrolyzable ligand; and

1≤a≤2, b≥1, c≥1 and b+c≤5.

In some embodiments, M is selected from the group consisting of Sn, Bi, Sb, In, Te, and combinations thereof. In some embodiments, L is a C3-C6 alkyl, alkenyl. In some embodiments, L is selected from the group consisting of propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, secondary pentyl, tertiary pentyl, hexyl, isohexyl, secondary hexyl, tertiary hexyl, and combinations thereof. In some embodiments, L is fluorinated such that the alkyl or alkenyl is substituted with one or more fluoro groups.

In some embodiments, X is any moiety that readily reacts with a second compound to produce -OH, such as a moiety selected from the group consisting of amines, including dialkylamino and monoalkylamino; alkoxy; carboxylates, halogens, and sulfonates. In some embodiments, the sulfonate group is substituted with one or more amine groups. In some embodiments, the halide is one or more selected from the group consisting of F, Cl, Br, and I. In some embodiments, the sulfonate group includes a substituted or unsubstituted C1-C3 group.

In some embodiments, the second compound is at least one of an amine, a borane, a phosphine, or water. In some embodiments, the amine has the formula NpHnXm, wherein 0≤n≤3, 0≤m≤3, n+m＝3 when p is 1, and n+m＝4 when p is 2, and each X is independently a halogen selected from the group consisting of F, Cl, Br, and I. In some embodiments, the borane has the formula BpHnXm, wherein 0≤n≤3, 0≤m≤3, n+m＝3 when p is 1, and n+m＝4 when p is 2, and each _X is independently a halogen selected from the group consisting of F, Cl, Br, and I. In some embodiments, the _phosphine has the formula _PpHnXm , wherein 0≤n≤3, 0≤m≤3, n+m＝3 when p is 1, or n+m＝4 when p is 2, and each X is independently a halogen selected from the group consisting of F, Cl, Br, and I.

In some embodiments, the second compound is water, ammonia or hydrazine. The reaction products of water, ammonia or hydrazine with the organometallic compound can form hydrogen bonds, which increase the boiling point of the reaction product and prevent emission of the metal photoresist material, thereby preventing metal contamination. Hydrogen bonds can also help prevent moisture from affecting the quality of the photoresist layer.

4B shows the reaction between the organometallic compound 402 and water. As shown in FIG4B , in the presence of water, the organometallic compound 402 is hydrolyzed, i.e., the hydroxyl group replaces the hydrolyzable ligand and bonds to the core M to obtain a hydroxyl-containing compound 404. More than one hydroxyl-containing compound 404 may undergo a condensation reaction to form an organometallic polymer 406. It should be noted that although the organometallic polymer 406 includes three organometallic compounds 402, organometallic polymers with fewer or more organometallic compounds 402 are also contemplated.

In some embodiments, the organometallic compound includes secondary hexyl tin (dimethylamino), tertiary hexyl tin (dimethylamino), isohexyl tin (dimethylamino), n-hexyl tin (dimethylamino), secondary amyl tin (dimethylamino), tertiary amyl tin (dimethylamino), isoamyl tin (dimethylamino), n-amyl tin (dimethylamino), secondary butyl tin (dimethylamino), tertiary butyl tin (dimethylamino), isobutyl tin (dimethylamino), n-butyl tin (dimethylamino), secondary butyl tin (dimethylamino), isopropyl tin (dimethylamino), n-propyl tin (diethylamino) , and similar alkyl (tin) (tertiary butoxy) tin compounds, including secondary hexyl tin (tertiary butoxy) tin, tertiary hexyl tin (tertiary butoxy) tin, isohexyl tin (tertiary butoxy) tin, n-hexyl tin (tertiary butoxy) tin, secondary amyl tin (tertiary butoxy) tin, tertiary amyl tin (tertiary butoxy) tin, isopentyl tin (tertiary butoxy) tin, n-pentyl tin (tertiary butoxy) tin, tertiary butyl tin (tertiary butoxy) tin, isobutyl tin (butoxy) tin, n-butyl tin (butoxy) tin, secondary butyl tin (butoxy) tin, isopropyl (tin) dimethylamino tin or n-propyl tin (butoxy) tin. In some embodiments, the organometallic compound is fluorinated. In some embodiments, the boiling point of the organometallic compound is less than about 200°C.

In some embodiments, the organometallic compound has one of the following structures:

In some embodiments, the photoresist layer 220 is formed by applying a photoresist composition to the cross-linked coating layer 212 using, for example, spin coating. In some embodiments, the photoresist composition includes at least one organic metal compound and at least one solvent. The amount of the organic metal compound in the photoresist composition may be about 0.5 wt % to 10 wt %. In some embodiments, the photoresist composition may include about 1 wt % of the organic metal compound.

In some embodiments, after the photoresist layer 220 is disposed on the cross-linked coating layer 212, a pre-exposure baking process may be performed to remove the solvent from the photoresist layer 220. The baking temperature is selected so that the pre-exposure baking process does not cause the cleavage of the acid-labile groups 312 of the switchable polymer 302 in the cross-linked coating layer 212. In some embodiments, the pre-exposure baking process may be performed at a temperature of about 40° C. to about 140° C. for 10 seconds to 5 minutes. In some embodiments, the photoresist layer 220 and the cross-linked coating layer 212 are heated at a temperature of about 60° C. to about 120° C. for 20 seconds to 3 minutes.

1 and 2D, according to some embodiments, the method 100 proceeds to operation 108, where the photoresist layer 220 and the cross-linked coating layer 212 are exposed to radiation 230. FIG2D is a cross-sectional view of the semiconductor device 200 after exposing the photoresist layer 220 and the cross-linked coating layer 212 to radiation 230, according to some embodiments.

The photoresist layer 220 and the cross-linked coating layer 212 are exposed to radiation 230 from a light source through a photomask 240. The photomask 240 has a predefined pattern designed for the IC based on the specifications of the IC to be manufactured. The pattern of the photomask 240 corresponds to the pattern of the materials that make up the various elements of the IC device to be manufactured. For example, a portion of the IC design layout includes various IC features such as active regions to be formed in the substrate 202, gate electrodes, source and drain electrodes, metal lines or vias for interlayer interconnects, and openings for bonding pads.

In some embodiments, the photomask 240 includes a first area 242 and a second area 244. In the first area 242, the radiation 230 is blocked by the photomask 240 from reaching the photoresist layer 220 and the cross-linked coating layer 212, while in the second area 244, the radiation 230 is not blocked by the photomask 240 and can pass through the photomask 240 to reach the photoresist layer 220 and the cross-linked coating layer 212. Therefore, the photomask 240 is used to form exposed areas 220e and unexposed areas 220u of the photoresist layer, and exposed areas 212e and unexposed areas 212u of the cross-linked coating layer 212. In some embodiments, the exposure to the radiation 230 is performed by placing the photoresist-coated substrate 202 in a photolithography tool. The photolithography tool includes the photomask 240, an optical device, an exposure radiation source that provides the radiation 230 for exposure, and a movable stage for supporting and moving the substrate 202 under the radiation 230.

In some embodiments, radiation 230 is EUV radiation (e.g., 13.5 nm). Alternatively, in some embodiments, radiation 230 is DUV radiation (e.g., 248 nm KrF excimer laser or 193 nm ArF excimer laser), X-ray radiation, electron beam radiation, ion beam radiation, or other suitable radiation. In some embodiments, operation 108 is performed in a liquid (immersion lithography) or in a vacuum for EUV etching and electron beam etching.

In some embodiments, the exposed areas 220e of the photoresist layer 220 irradiated by the radiation 230 undergo further condensation reactions to form metal clusters, while the unexposed areas 220u not irradiated by the radiation 230 do not undergo condensation reactions. The exposed areas 220e of the photoresist layer 220 may constitute a latent pattern. Since the metal clusters are substantially insoluble in the developer used in the subsequent development process, the exposed areas 220e of the photoresist layer 220 irradiated by the radiation 230 are substantially insoluble in the developer. The unexposed areas 220u not irradiated by the radiation 230 do not undergo condensation reactions and are soluble in the developer. The difference in solubility allows the latent pattern to be developed in the development process.

5 illustrates the reaction of an organometallic compound in some embodiments as a result of exposure to radiation 230. As a result of exposure to radiation 230, ligand L is cleaved from the metal core M ⁺ of the organometallic compound, and two or more organometallic compound cores bond to each other to form a metal oxide cluster.

Upon irradiation, the acid generator 320, such as PAG or TAG, in the exposure region 212e of the cross-linked coating layer 212 absorbs energy to generate acid. The acid generated during exposure to radiation 230 cleaves the acid labile group (ALG) from the cross-linked switchable polymer in the cross-linked coating layer 212, thereby forming a reactive functional group, such as -COOH or -OH, in the exposure region 212e. The reactive functional group in the cross-linked coating layer 212 then reacts with the hydroxyl group (OH) in the hydrolyzed organometallic compound (M-OH). The resulting covalent bond formed between the photoresist layer 220 and the cross-linked coating layer 212 helps to enhance the collapse window, LWR and fine-tune the resist profile shape.

6A shows a deprotection reaction of an acid labile group (ALG) 312 according to an embodiment of the present disclosure. When the cross-linked coating layer 212 is exposed to radiation 230, the acid generator 320 generates an acid (H ⁺ ) that cleaves the acid labile group (ALG) 312 and generates a carboxyl group (-COOH) or a hydroxyl group (-OH) on the polymer side chain.

FIG6B shows the condensation reaction between the ALG-cleaved cross-linked switchable polymer and the hydrolyzed organometallic compound (M-OH).

Next, the photoresist layer 220 is subjected to post-exposure baking (PEB). In some embodiments, the photoresist layer 220 is heated at a temperature of about 50° C. to about 250° C. for about 20 seconds to about 300 seconds. In some embodiments, the post-exposure baking is performed at a temperature in the range of about 100° C. to about 230° C., and in other embodiments at a temperature in the range of about 150° C. to about 200° C. During the PEB operation, more acid is generated in the exposed area 212 e of the cross-linked coating layer 212. The generated acid promotes the deprotection reaction of the ALG and the condensation reaction between the cross-linked coating layer 212 and the photoresist layer 220.

1 and 2E, according to some embodiments, the method 100 proceeds to operation 110, where the photoresist layer 220 and the cross-linked coating layer 212 are developed to form a patterned photoresist layer 220p and a patterned cross-linked coating layer 212p. FIG2E is a cross-sectional view of the semiconductor device 200 after developing the photoresist layer 220 and the cross-linked coating layer 212 to form a patterned photoresist layer 220p and a patterned cross-linked coating layer 212p according to some embodiments.

In some embodiments, the photoresist layer 220 is developed by applying a solvent-based developer to the photoresist layer 220. In some embodiments, the exposed regions 220e of the photoresist layer 220 undergo a metal cluster formation reaction due to exposure to radiation, and the unexposed regions 220u of the photoresist layer 220 are removed by the developer forming a pattern of openings 250 in the photoresist layer 220 to expose the substrate 202. In some embodiments, the cross-linked coating layer 212 located below the unexposed regions 220u of the photoresist layer 220 is removed during the development operation.

In some embodiments, the resist developer includes a solvent and an acid or base. In some embodiments, the concentration of the solvent is about 60 wt.% to about 99 wt.% based on the total weight of the resist developer. The concentration of the acid or base is about 0.001 wt.% to about 20 wt.% based on the total weight of the resist developer. In certain embodiments, the concentration of the acid or base in the developer is about 0.01 wt.% to about 15 wt.% based on the total weight of the developer.

In some embodiments, the developer is applied to the photoresist layer 220 using a spin coating process. In the spin coating process, the developer is applied to the photoresist layer 220 from above the photoresist layer 220 while the photoresist-coated substrate 202 is rotated. In some embodiments, the developer is supplied at a rate between about 5 ml/min and about 800 ml/min, while the photoresist-coated substrate 202 is rotated at a speed between about 100 rpm and about 2000 rpm. In some embodiments, the developer is at a temperature between about 10° C. and about 80° C. In some embodiments, the development operation lasts from about 30 seconds to about 10 minutes.

In some embodiments, the developer includes an organic solvent. The organic solvent may be any suitable solvent. In some embodiments, the solvent is one or more selected from the following: propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), 1-ethoxy-2-propanol (PGEE), γ-butyrolactone (GBL), cyclohexanone (CHN), ethyl lactate (EL), methanol, ethanol, propanol, n-butanol, 4-methyl-2-pentanol, acetone, methyl ethyl ketone, dimethylformamide (DMF), isopropyl alcohol (IPA), tetrahydrofuran (THF), methyl isobutyl carbinol (MIBC), n-butyl acetate (nBA), 2-heptanone (MAK) and dioxane.

Although spin coating is a suitable method for developing photoresist layer 220 after exposure, it is intended to be illustrative and not intended to limit the embodiment. Instead, any suitable developing operation may be used alternatively, including dipping process, stirring process and spraying method. All such developing operations are included within the scope of the embodiment.

In some embodiments, a dry developer is applied to the photoresist layer 220. In some embodiments, the dry developer is a plasma or a chemical vapor, and the dry development operation is a plasma etch or a chemical etch operation. Dry development uses differences related to composition, degree of crosslinking, and film density to selectively remove desired portions of the resist. In some embodiments, the dry development process uses a mild plasma (high voltage, low power) or a thermal process in a heated vacuum chamber while flowing a dry development chemical, such as BCl ₃ , BF ₃ , or other Lewis acids in a vapor state. In some embodiments, BCl ₃ removes unexposed material, leaving a pattern of exposed film, which is transferred to the underlying layer by a plasma-based etching process.

In some embodiments, the dry development includes a plasma process, including transformer coupled plasma (TCP), inductively coupled plasma (ICP) or capacitively coupled plasma (CCP). In some embodiments, the plasma process is performed at a pressure in the range of about 5 mTorr to about 20 mTorr, a power level of about 250 W to about 1000 W, a temperature in the range of about 0° C. to about 300° C., and a flow rate of about 100 sccm to about 1000 sccm for about 1 second to about 3000 seconds.

In some embodiments, the photoresist is a negative resist, and the unexposed regions 220u of the photoresist layer 220 are removed by a developing operation. In other embodiments, the photoresist is a positive resist, and the exposed regions 220e of the photoresist layer 220 are removed by a developing operation.

1 and 2F, according to some embodiments, the method 100 proceeds to operation 112, in which the substrate 202 is etched using the patterned photoresist layer 220p and the patterned cross-linked coating layer 212p as an etching mask. FIG2F is a cross-sectional view of the semiconductor device 200 after etching the substrate 202 using the patterned photoresist layer 220p and the patterned cross-linked coating layer 212p as an etching mask according to some embodiments.

As shown in FIG. 2F , the substrate 202 is patterned using the patterned photoresist layer 220P as an etching mask to form a recess 260 in the substrate 202 .

An etching process may be performed to transfer the pattern in the patterned photoresist layer 220p to the substrate 202. In some embodiments, the etching process employed is an anisotropic etching such as dry etching, although any suitable etching process may be employed. In some embodiments, the dry etching is reactive ion etching (RIE) or plasma etching. In some embodiments, the dry etching is performed by a fluorine-containing gas (e.g., CF ₄ , SF ₆ , CH ₂ F ₂ , CHF ₃ and/or C ₂ F ₆ ), a chlorine-containing gas (e.g., Cl ₂ , CHCl ₃ , CCl ₄ and/or BCl ₃ ), a bromine-containing gas (e.g., HBr and/or CHBr ₃ ), an oxygen-containing gas, an iodine-containing gas, other suitable gases and/or plasma, or a combination thereof. In some embodiments, oxygen plasma is performed to etch the substrate 202. In some embodiments, the anisotropic etching is performed at a temperature of about 250° C. to 450° C. for a duration of about 20 seconds to about 300 seconds.

If not completely consumed in the etching process, after forming the recess 260 , the patterned photoresist layer 220 p and the patterned cross-linked coating layer 212 p are removed, for example, by plasma ashing or wet stripping.

FIG. 7 is a flow chart showing a method 700 for forming a semiconductor device 200 according to some embodiments of the present disclosure. FIGS. 8A to 8E are cross-sectional views of a semiconductor device 200 at various stages of manufacture according to some embodiments of the present disclosure. Intermediate steps of method 700 are described with reference to cross-sectional views of semiconductor device 200 as shown in FIGS. 8A to 8E. Unlike method 100 in which coating layer 210 is formed as a bottom layer below a photoresist layer, in method 700, coating layer 210 is formed as a top coating layer above photoresist layer 220. Unless otherwise specified, the materials and formation methods of the elements in these embodiments are substantially the same as those of similar elements, which are indicated by similar element symbols in the embodiments shown in FIGS. 2A to 2F. Therefore, detailed information on the formation process and element materials shown in FIGS. 8A to 8E is found in the discussion of the embodiments shown in FIGS. 2A to 2F.

7 and 8A, according to some embodiments, method 700 includes operation 702, in which a photoresist layer 220 is formed over substrate 202. FIG8A is a cross-sectional view of semiconductor device 200 after forming photoresist layer 220 over substrate 202 according to some embodiments. In some embodiments, photoresist layer 220 includes an organic metal compound and is formed by the above-described manufacturing process in FIG2C.

7 and 8B, according to some embodiments, the method 700 proceeds to operation 704, where a coating layer 210 is formed over the photoresist layer 220. FIG8B is a cross-sectional view of the semiconductor device 200 after forming the coating layer 210 over the photoresist layer 220 according to some embodiments. In some embodiments, the coating layer 210 includes a switchable polymer 302, an acid generator 320, and a quencher 330, and is formed by the above-described manufacturing process in FIG2A.

7 and 8C, according to some embodiments, the method 700 proceeds to operation 706, where the coating layer 210 is heated to form a cross-linked coating layer 212. FIG8C is a cross-sectional view of the semiconductor device 200 after forming the cross-linked coating layer 212 according to some embodiments. In some embodiments, the cross-linked coating layer 212 is formed by the above-described manufacturing process in FIG2B.

7 and 8D, according to some embodiments, the method 700 proceeds to operation 708, in which the cross-linked coating layer 212 and the photoresist layer 220 are exposed to radiation 230 to form exposed regions 212e and unexposed regions 212u in the cross-linked coating layer 212, and exposed regions 220e and unexposed regions 220u in the photoresist layer 220. FIG8D is a cross-sectional view of the semiconductor device 200 after exposing the cross-linked coating layer 212 and the photoresist layer 220 to the radiation 230, according to some embodiments. In some embodiments, exposing the cross-linked coating layer 212 and the photoresist layer 220 to the radiation 230 is performed by the above-described manufacturing process in FIG2D.

Upon irradiation, the acid generator 320, such as PAG or TAG, in the exposure region 212e of the cross-linked coating layer 212 absorbs energy to generate acid. The acid generated during exposure to radiation 230 cleaves the acid labile group (ALG) from the cross-linked switchable polymer in the cross-linked coating layer 212, thereby forming a reactive functional group, such as -COOH or -OH, in the exposure region 212e. The reactive functional group in the cross-linked coating layer 212 then reacts with the hydroxyl group (OH) in the hydrolyzed organometallic compound (M-OH). The resulting covalent bond formed between the photoresist layer 220 and the cross-linked coating layer 212 helps to enhance the collapse window, reduce LWR, and fine-tune the resist profile shape.

7 and 8E, according to some embodiments, the method 700 proceeds to operation 710, in which the cross-linked coating layer 212 and the photoresist layer 220 are developed to form a patterned cross-linked coating layer 212p and a patterned photoresist layer 220p. FIG8E is a cross-sectional view of the semiconductor device 200 after developing the cross-linked coating layer 212 and the photoresist layer 220 to form a patterned cross-linked coating layer 212p and a patterned photoresist layer 220p according to some embodiments. In some embodiments, the cross-linked coating layer 212 and the photoresist layer 220 are developed by the above-described manufacturing process in FIG2E.

7 , according to some embodiments, method 700 proceeds to operation 712, where substrate 202 is etched using patterned cross-linked coating layer 212p and patterned photoresist layer 220p. In some embodiments, substrate 202 is etched by the above-described manufacturing process in FIG. 2F to obtain an etched substrate as shown in FIG. 2F .

One aspect of the present specification is about a method for forming a semiconductor device. The method includes the step of forming a coating on a substrate, the coating including a switchable polymer and an acid generator. The switchable polymer includes a polymer backbone and a side group connected to the polymer backbone. The side group includes an acid-labile group and a cross-linking group. The method further includes the step of performing a baking process to cause the cross-linking group to undergo a cross-linking reaction to form a cross-linked coating. The method further includes the step of depositing a photoresist layer onto the cross-linked coating. The method further includes the step of selectively exposing the photoresist layer and the cross-linked coating to patterned radiation. The method further includes the step of developing the selectively exposed photoresist layer and the cross-linked coating to form a pattern of openings on the photoresist layer and the cross-linked coating.

In some embodiments, the acid generator comprises a photoacid generator or a thermal acid generator. In some embodiments, the baking process is performed at a temperature that causes crosslinking of the crosslinking groups but does not cause cleavage of the acid-labile groups. In some embodiments, the temperature is in the range of 80°C to 200°C. In some embodiments, the photoresist layer comprises an organic metal compound. In some embodiments, the coating layer further comprises a quencher. In some embodiments, the switchable polymer comprises 10-70wt.% of acid-labile groups and 30-70wt.% of crosslinking groups. In some embodiments, the switchable polymer further comprises a plurality of pendant floating groups connected to the polymer backbone. In some embodiments, the method further comprises removing portions of the substrate exposed by the openings.

Another aspect of the present specification is about a method for forming a semiconductor device. The method includes the step of depositing a photoresist layer comprising an organometallic compound onto a substrate. The method further includes the step of forming a coating layer on the photoresist layer. The coating layer includes a switchable polymer, an acid generator, and a quencher. The switchable polymer includes a polymer backbone and pendant acid-labile groups and cross-linking groups connected to the polymer backbone. The method further includes the step of heating the coating layer at a cross-linking temperature of the cross-linking group to form a cross-linked coating layer. The method further includes the step of selectively exposing the photoresist layer and the cross-linked coating layer to patterned radiation. The method further includes the step of developing the selectively exposed photoresist layer and the cross-linked coating layer to form a patterned cross-linked coating layer and a patterned photoresist layer.

In some embodiments, the patterned radiation is extreme ultraviolet or electron beam radiation, and the patterned radiation causes the acid generator to generate an acid, which causes the acid-labile group to cleave. In some embodiments, the method further includes etching the substrate using the patterned cross-linked coating layer and the patterned photoresist layer as an etching mask.

Yet another aspect of the present specification is about a method for forming a semiconductor device. The method includes the step of applying a coating composition to a substrate to form a coating layer. The coating composition includes a switchable polymer, an acid generator, and a solvent, wherein the switchable polymer has a polymer backbone and side groups including one or more acid-labile groups, one or more cross-linking groups, and one or more optional floating groups connected to the polymer backbone. The method further includes heating the substrate and the coating layer to a temperature at which one or more cross-linking groups react to cross-link the switchable polymer. The method further includes the step of forming a photoresist layer on the cross-linked coating layer. The method further includes the step of exposing the photoresist layer and the cross-linked coating layer to radiation through a photomask. The method further includes the step of removing the unexposed areas of the photoresist layer and the cross-linked coating layer by a developer to form a patterned photoresist layer and a patterned cross-linked coating layer.

In some embodiments, the switchable polymer has the following structure (I): Wherein L ¹ , L ² and L ³ are independently linear or C _1-10 alkylene, C _1-10 heteroalkylene, arylene, heteroarylene or heteroatom linker at each occurrence; Ra, Rb and Rc are independently hydrogen, C _1-10 alkyl or halogen at each occurrence; R ¹ is an acid-labile group at each occurrence; R ² is a cross-linking group at each occurrence; R ³ is a floating group at each occurrence; m and n are independently an integer of 1 or greater; and p is an integer of 0 or greater. In some embodiments, Ra, Rb and Rc are independently hydrogen or methyl. In some embodiments, R ¹ has one of the following structures:

In some embodiments, R ² has one of the following structures:

wherein R at each occurrence is hydrogen or an alkyl group having 1 to 10 carbon atoms; q is an integer from 1 to 300; and w is an integer from 1 to 6. In some embodiments, R ³ has one of the following structures:

In some embodiments, L ¹ , L ² and L ³ are independently an unsubstituted or halogen-substituted saturated C1-C9 cyclic or acyclic group, -S-, -P-, -P(O ₂ )-, -C(═O)S-, -C(═O)O-, -O-, -N-, -C(═O)N-, -SO ₂ O-, -SO ₂ S-, -SO-, -SO ₂ -, -C ₆ H ₆ -O-, -C ₆ H ₆ -OC(═O)O-, an ether group, a ketone group, an ester group or a phenylene group. In some embodiments, L ¹ , L ² and L ³ are independently one of the following structures:

The features of several embodiments are summarized above so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and/or achieve the same advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and various modifications, substitutions, and changes may be made herein without departing from the spirit and scope of the present disclosure.

Claims (10)

1. A method for forming a semiconductor device, comprising:

forming a coating layer over a substrate, the coating layer comprising a switchable polymer and an acid generator, the switchable polymer comprising a polymer backbone and a plurality of pendent groups attached to the polymer backbone, wherein the plurality of pendent groups comprise a plurality of acid-labile groups and a plurality of crosslinking groups;

performing a baking process to make the crosslinking groups undergo a crosslinking reaction so as to form a crosslinked coating layer;

Depositing a photoresist layer over the crosslinked coating layer;

exposing the photoresist layer and the crosslinked coating layer selectively to a patterning radiation; and

developing the selectively exposed photoresist layer and the crosslinked coating layer to form a pattern of openings in the photoresist layer and the crosslinked coating layer.

2. The method for forming the semiconductor device of claim 1, wherein the switchable polymer further comprises a plurality of pendant floating groups attached to the polymer backbone.

3. A method for forming a semiconductor device, comprising:

depositing a photoresist layer comprising an organometallic compound over a substrate;

forming a coating layer over the photoresist layer, the coating layer comprising a switchable polymer, an acid generator, and a quencher, the switchable polymer comprising a polymer backbone and a plurality of pendant acid labile groups and a plurality of crosslinking groups attached to the polymer backbone;

heating the coating layer at a crosslinking temperature of the plurality of crosslinking groups to form a crosslinked coating layer;

exposing the photoresist layer and the crosslinked coating layer selectively to a patterning radiation; and

Developing the selectively exposed photoresist layer and the crosslinked coating layer to form a patterned crosslinked coating layer and a patterned photoresist layer.

4. A method for forming a semiconductor device, comprising:

applying a coating composition to a substrate to form a coating layer, the coating composition comprising a switchable polymer having a polymer backbone and a plurality of pendent groups comprising one or more acid-labile groups, one or more crosslinking groups, and one or more optional float groups attached to the polymer backbone, an acid generator, and a solvent;

heating the substrate and the coating layer to a temperature at which the one or more crosslinking groups react to crosslink the switchable polymer, thereby forming a crosslinked coating layer;

forming a photoresist layer over the crosslinked coating layer;

exposing the photoresist layer and the crosslinked coating layer to radiation through a photomask; and

the photoresist layer and the plurality of unexposed areas of the crosslinked coating layer are removed by a developer to form a patterned photoresist layer and a patterned crosslinked coating layer.

5. The method for forming the semiconductor device of claim 4, wherein the switchable polymer has the following structure (I):

Wherein:

L ¹ 、L ² l and L ³ Independently at each occurrence a straight chain or a C _1-10 Alkylene, C _1-10 A heteroalkylene, arylene, heteroarylene, or heteroatom linker;

ra, rb, and Rc are, at each occurrence, independently hydrogen, C _1-10 Alkyl or halogen;

R ¹ an acid labile group at each occurrence;

R ² at each occurrence is a crosslinking group;

R ³ at each occurrence is a drift group;

m and n are independently an integer of 1 or more; and is also provided with

p is an integer of 0 or more.

6. The method for forming the semiconductor device according to claim 5, wherein R ¹ Has one of the following structures:

7. the method for forming the semiconductor device according to claim 5, wherein R ² Has one of the following structures:

wherein:

r is hydrogen or a mono-alkyl group having 1 to 10 carbon atoms at each occurrence;

q is an integer from 1 to 300; and is also provided with

w is an integer from 1 to 6.

8. The method for forming the semiconductor device according to claim 5, wherein R ³ Has one of the following structures:

9. the method for forming the semiconductor device according to claim 5, wherein L ¹ 、L ² L and L ³ Independently an unsubstituted or halogen-substituted, saturated C1-C9 cyclic or acyclic group, -S-, -P (O) ₂ )-、-C(＝O)S-、-C(＝O)O-、-O-、-N-、-C(＝O)N-、-SO ₂ O-、-SO ₂ S-、-SO-、-SO ₂ -、-C ₆ H ₆ -O-、-C ₆ H ₆ -O-C (=o) O-, monoether-, mono-ketone-, mono-ester-or mono-phenylene.

10. The method for forming the semiconductor device according to claim 5, wherein L ¹ 、L ² L and L ³ Independently having one of the following structures: