Bottom anti-reflective coating

Abstract

The present disclosure relates to bottom anti-reflective coatings. A method according to the present disclosure includes: providing a substrate; depositing an underlayer over the substrate; depositing a photoresist layer over the underlayer; exposing a portion of the photoresist layer and a portion of the underlayer to a radiation source according to a pattern; baking the photoresist layer and the underlayer; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer. The underlayer includes: a polymer backbone; a polarity switchable group; a crosslinkable group bonded to the polymer backbone; and a photoacid generator. The polarity switchable group includes: a first end group bonded to the polymer backbone, a second end group including fluorine, and an acid-labile group bonded between the first end group and the second end group. The exposure decomposes the photoacid generator to generate an acidic portion, which separates the second end group from the polymer backbone during baking.

Description

Technical Field

[0001] The present disclosure relates generally to bottom anti-reflective coatings. Background Art

[0002] The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced several generations of ICs, each with smaller and more complex circuits than the previous generation. In the course of IC evolution, 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 shrinking process generally provides benefits by increasing production efficiency and reducing associated costs. This shrinking has also increased the complexity of processing and manufacturing ICs, and similar developments in IC processing and manufacturing are needed to achieve these advances.

[0003] In one exemplary aspect, photolithography is a process used in semiconductor microfabrication to selectively remove a portion of a film or substrate. The process uses light to transfer a pattern (e.g., a geometric pattern) from a photomask to a photosensitive layer (e.g., a photoresist layer) on a substrate. The light causes a chemical change (e.g., an increase or decrease in solubility) in the exposure area of ​​the photosensitive layer. A baking process can be performed before and / or after exposing the substrate, for example, in a pre-exposure and / or post-exposure baking process. The pre-exposure baking process may also be referred to as a post-application exposure process. Then, the developing process selectively removes the exposed or unexposed areas with a developer solution, thereby forming an exposure pattern on the substrate. Finally, a process is implemented to remove (or strip) the remaining photoresist from the underlying (one or more) material layers, which process may be subjected to additional circuit manufacturing steps. For complex IC devices, the substrate may undergo multiple photolithography patterning processes. Although conventional underlying components and photolithography processes are generally sufficient to meet their intended purposes, they are not completely satisfactory. For example, in some IC manufacturing scenarios, a photoresist layer may be deposited directly on an underlying layer (e.g., a bottom anti-reflective coating (BARC) layer) to pattern a material layer below the underlying layer. Due to the affinity of the photoresist layer to the underlying layer, scum or residual photoresist material may remain in the exposure pattern on the underlying layer. Additional improvements are needed. Summary of the invention

[0004] According to one embodiment of the present disclosure, a method for manufacturing a semiconductor device is provided, comprising: providing a substrate; depositing a bottom layer over the substrate, the bottom layer comprising: a polymer main chain; a polarity switchable group comprising: an acid-labile group bonded to a first end group of the polymer main chain, a second end group comprising fluorine, and a bonded between the first end group and the second end group; a cross-linkable group bonded to the polymer main chain; and a photoacid generator; depositing a photoresist layer over the bottom layer; exposing a portion of the photoresist layer and a portion of the bottom layer to a radiation source according to a pattern, thereby decomposing the photoacid generator in the exposed portion of the bottom layer to generate an acidic portion; baking the photoresist layer and the bottom layer so that the acidic portion reacts with the acid-labile group to separate the second end group from the polymer main chain; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer.

[0005] According to another embodiment of the present disclosure, a method for manufacturing a semiconductor device is provided, comprising: providing a substrate; depositing a bottom layer over the substrate, wherein the bottom layer comprises: a polymer backbone; a fluorine-containing group bonded to the polymer backbone; a polar group bonded to the polymer backbone; a thermally cross-linkable group bonded to the polymer backbone; a cross-linker; and a thermal acid generator comprising an acidic portion configured to catalyze the bonding between the polar group and the cross-linker; depositing a photoresist layer over the bottom layer; exposing a portion of the photoresist layer to a radiation source according to a pattern; baking the photoresist layer; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer.

[0006] According to another embodiment of the present disclosure, a method for manufacturing a semiconductor device is provided, comprising: providing a substrate; depositing a bottom layer over the substrate, wherein the bottom layer comprises: a polymer backbone; an acid-labile group bonded to the polymer backbone; an ultraviolet (UV) curable group bonded to the acid-labile group; a thermal acid generator configured to release an acidic portion at a first temperature; and a photobase generator configured to release an alkaline portion when exposed to a radiation source; depositing a photoresist layer over the bottom layer; baking the photoresist layer at a second temperature lower than the first temperature; exposing a portion of the photoresist layer and a portion of the bottom layer to a radiation source according to a pattern, thereby releasing the alkaline portion from the photobase generator; baking the bottom layer at the first temperature, thereby releasing the acidic portion to neutralize the alkaline portion; and developing the exposed portion of the photoresist layer and the exposed portion of the bottom layer to transfer the pattern to the photoresist layer and the bottom layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Various aspects of the present disclosure may 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, various features are not drawn to scale and are for illustration purposes only. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0008] Figure 1 A flow chart of a method for manufacturing a semiconductor device according to various aspects of the present disclosure is shown.

[0009] Figure 2A Components of a first coating solution for forming a base layer according to various aspects of the present disclosure are shown.

[0010] Figure 2B Polarity switchable groups in a first coating solution according to various aspects of the present disclosure are shown.

[0011] Figure 3-Figure 10 According to various aspects of the present disclosure Figure 1 FIG. 2 is a partial cross-sectional view of a workpiece at an intermediate step of the method and using the first coating solution in FIG. 2 .

[0012] Fig.11 Components of a second coating solution for forming a base layer according to various aspects of the present disclosure are shown.

[0013] Figure 12-Figure 27 According to various aspects of the present disclosure Figure 1 In the middle step of the method and use Fig.11 A partial cross-sectional view of a workpiece in which the second coating solution is applied.

[0014] Fig.28 Components of a third coating solution for forming a base layer according to various aspects of the present disclosure are shown.

[0015] Figure 29-Figure 37 According to various aspects of the present disclosure Figure 1 In the middle step of the method and use Fig.28 A partial cross-sectional view of the workpiece in the third coating solution. DETAILED DESCRIPTION

[0016] The following disclosure provides many different embodiments or examples for realizing the different features of the present disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be restrictive. For example, in the following description, forming a first feature above or on a second feature may include an embodiment in which the first feature and the second feature are formed in 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 in direct contact. In addition, the present disclosure may repeat reference numbers and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or configurations discussed.

[0017] In addition, the present disclosure may repeat reference numbers and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or configurations discussed. In addition, in the present disclosure below, a feature formed on, connected to, and / or coupled to another feature may include an embodiment in which the feature is formed in a direct contact manner, and may also include an embodiment in which additional features may be formed between features so that the features may not be in direct contact. In addition, spatially related terms (e.g., "lower", "upper", "horizontal", "vertical", "above", "above", "below", "below", "up", "down", "top", "bottom", etc. and their derivatives (e.g., "horizontally", "downward", "upward", etc.)) are used to easily present the relationship of one feature to another feature. Spatially related terms are intended to cover different orientations of devices including features. Further, when a number or a range of numbers is described with "about", "approximately", etc., unless otherwise specified, the term is intended to cover numbers within + / -10% of the described number. For example, the term "about 5nm" covers a size range from 4.5nm to 5.5nm.

[0018] The present disclosure generally relates to semiconductor device manufacturing, and more specifically, to the composition of the bottom layer and the photolithography process for reducing scum. In some semiconductor manufacturing scenarios, a photoresist layer is directly deposited on the bottom layer, for example, a bottom anti-reflective coating (BARC) layer deposited on a material layer. A photolithography process is then applied to pattern the photoresist layer to form a patterned photoresist layer. The material layer is then etched using the patterned photoresist layer as an etching mask to form a patterned material layer. The patterned material layer is then used as an etching mask to etch and pattern the layer below the material layer to form various semiconductor device features and contact structures. For example, when extreme ultraviolet (EUV) is used as a radiation source for lithography, an organometallic photoresist that absorbs EUV can be used. The organometallic photoresist can include metals, for example, tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium. An example of an organometallic photoresist is tin-oxygen cage compound (SnOx). In order to introduce unique etching selectivity, the material layer patterned using a patterned organic metal photoresist layer can be a carbon-containing layer, for example, a spin-on carbon (SOC) layer. The bottom layer is arranged between the material layer and the organic metal photoresist layer, and its thickness can be between about 3nm and 30nm. In some cases, the bottom layer can be a bottom anti-reflective coating (BARC) layer, which improves the adhesion of the organic metal photoresist and / or reduces the reflection of radiation from the bottom interface of the organic metal photoresist layer. Although some embodiments of the present disclosure will be described below in conjunction with the organic metal photoresist layer, it will be understood by those skilled in the art that these embodiments can also be implemented when using other types of photoresist layers, as long as these types of photoresist layers are directly deposited on the bottom layer.

[0019] The present disclosure discloses a coating solution for depositing a bottom layer that reduces scum formation and a method for depositing a bottom layer using the disclosed coating solution. In some embodiments, the first bottom layer formed using the first coating solution includes a fluorine-containing group that can be cracked after being exposed to a radiation source. Because the fluorine-containing group reduces the affinity between the photoresist layer and the first bottom layer, less residual photoresist material or scum will remain on the first bottom layer after the exposed photoresist layer is developed. In some other embodiments, the second bottom layer formed using the second coating solution includes a permanently bonded fluorine-containing group. Because the fluorine-containing group reduces the affinity between the photoresist layer and the second bottom layer, less residual photoresist material or scum can be left after the exposed photoresist layer is developed. In some other embodiments, the third bottom layer formed using the third coating solution includes a photobase generator and a thermal acid generator. Since the unexposed third bottom layer can be selectively removed together with the unexposed photoresist in a negative tone development (NTD) process, less residual photoresist material or scum can be left after the exposed photoresist layer is developed. By reducing the amount of remaining photoresist / scum, the embodiments of the present disclosure expand the process window and improve the yield.

[0020] Figure 1 A flow chart of a method 10 for fabricating a semiconductor device on a workpiece is shown. The method 10 is merely an example and is not intended to limit the present disclosure beyond what is expressly recited in the claims. Other operations may be provided before, during, and after the method 10, and some of the operations described may be replaced, eliminated, or moved for other embodiments of the process. The operations of the method 10 will be described below with reference to Figure 3-Figure 10 When using the Figure 2A and Figure 2B The operation of method 10 will be described below with reference to the cross-sectional view of workpiece 200 when first coating solution 100 of the composition shown is used to form a first bottom layer. Figure 12-Figure 27 When using the Fig.11 The operation of method 10 will be described below with reference to the cross-sectional view of workpiece 400 or workpiece 500 when a second coating solution 300 of the composition shown is used to form a second bottom layer. Figure 29-Figure 37 When using with Fig.28 A cross-sectional view of a workpiece 700 when the composition of the third coating solution 600 is used to form a third bottom layer will be described.

[0021] refer to Figure 1 and Figure 3, method 10 includes block 12, in which a substrate 202 is received. In some embodiments, substrate 202 may include: a basic (single element) semiconductor, such as silicon and / or germanium; a compound semiconductor, such as silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, and / or indium antimonide; an alloy semiconductor, such as SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and / or GaInAsP; a non-semiconductor material, such as soda-lime glass, fused silica, fused quartz, and / or calcium fluoride (CaF2); and / or combinations thereof. In some other embodiments, substrate 202 may be a single layer of material having a uniform composition; alternatively, substrate 202 may include multiple material layers having similar or different compositions suitable for IC device fabrication. In one example, substrate 202 may be a silicon-on-insulator (SOI) substrate having a semiconductor silicon layer formed on a silicon oxide layer. In other examples, substrate 202 may include a conductive layer, a semiconductor layer, a dielectric layer, other layers, and / or combinations thereof. Substrate 202 may include various circuit features formed thereon, including, for example, field effect transistors (FETs), metal oxide semiconductor field effect transistors (MOSFETs), CMOS transistors, high voltage transistors, high frequency transistors, bipolar junction transistors, diodes, resistors, capacitors, inductors, varactors, other suitable devices, and / or combinations thereof. In some embodiments where substrate 202 includes FETs, various doped regions, such as source / drain regions, are formed on substrate 202. The doped regions may be doped with p-type dopants (e.g., phosphorus or arsenic) and / or n-type dopants (e.g., boron or BF2), depending on design requirements. The doped regions may be planar or non-planar (e.g., in fin FET devices), and may be formed directly on substrate 202 in a P-well structure, an N-well structure, a dual-well structure, or using a raised structure. The doped regions may be formed by implanting dopant atoms, in-situ doping epitaxial growth, and / or other suitable techniques.

[0022] Despite Figure 3 202. Although not shown in the figure, substrate 202 may include a material layer so that the material layer constitutes the uppermost layer of substrate 202. The composition of the material layer may be selected so that the material layer can be etched without substantially etching the patterned photoresist layer. In this way, the patterned photoresist layer can be used as an etching mask to selectively etch the material layer. In embodiments where the photoresist layer deposited above the material layer is an organic metal photoresist layer including a metal, the material layer may include carbon. In some cases, the material layer may be a spin-on carbon (SOC) layer. In some embodiments, substrate 202 may further include a spin-on glass (SOG) layer, which includes silicon oxide and the material layer is deposited on the SOG layer.

[0023] refer to Figure 1 , Figure 2A , Figure 2B and Figure 4 The method 10 includes block 14, wherein a first bottom layer 204 is formed over the substrate 202. In some embodiments, the first bottom layer 204 may be formed using Figure 2A The first coating solution 100 schematically shown in FIG. 1 is spin-coated on a substrate 202 to form a bottom anti-reflective coating (BARC) layer. The first coating solution 100 includes a solvent 101, a polymer backbone 102, a cross-linkable group 104, a polarity switchable group 106, a photoresist affinity group 108, a photoacid generator 110, and an additive 112. Figure 2A In some embodiments shown, the crosslinkable groups 104, the polarity switchable groups 106, and the photoresist-affinity groups 108 are each chemically bonded to the polymer backbone 102. In some embodiments, the polarity switchable groups 106 and the photoresist-affinity groups 108 are each covalently bonded to the polymer backbone 102. The solvent 101 can be an organic solvent and can include alkanes, alkenes, alcohols, ketones, ethers, esters, imines, amides, dimethylformamide (DMF), sulfones, sulfoxides, dimethyl sulfoxide (DMSO), cyanides, acetonitrile, dichloromethane, propylene glycol methyl ether (PGME), benzene, amines, n-butyl acetate, 2-heptanone, cyclohexanone, dichloromethane, toluene, propylene glycol methyl ether acetate (PGMEA), methyl ethyl ketone (MEK), diethyl phthalate, formic acid, or mixtures thereof.

[0024] The polymer backbone 102 may include polystyrene (PS), poly(hydroxystyrene) (PHS), poly(methyl methacrylate) (PMMA), poly(methacrylate) (PMA), poly(norbornene)-maleic anhydride (COMA), or other suitable polymers, or block copolymers thereof. In some embodiments, the crosslinkable group 104 may be an ultraviolet (UV) curable group or a thermal crosslinkable group. With respect to the former, exposure to UV may generate one or more free radicals on the UV curable group, thereby allowing it to bond to another UV curable group or another polymer backbone other than the polymer backbone 102 through a free radical polymerization reaction. With respect to the latter, exposure to an elevated temperature during a baking process may cause the thermal crosslinkable group to bond to another crosslinkable group or another polymer backbone 102 through a condensation reaction. In some embodiments, the crosslinkable group 104 may include a non-cyclic structure or a cyclic alkyl structure having 2 to 30 carbon atoms. In embodiments where the crosslinkable group 104 is a thermally crosslinkable group, the crosslinkable group 104 may include a functional group, for example, a halide group (-I, -Br, -Cl), an amine group (-NH2), a carboxylic acid group (-COOH), a hydroxyl group (-OH), a thiol group (-SH), a nitride (-N3) group, an epoxy group, an alkynyl group, an alkenyl group, a ketone group, an aldehyde, an ester group, an acyl halide, an NHS ester group, an imidoester group, a pentafluorophenyl ester group, a hydroxymethylphosphine, a carbodiimide, a maleimide, a haloacetyl group, a pyridyldisulfide group, a thiosulfonate, a vinyl sulfone, a hydrazide, an alkoxyamine, a diazirine, an aromatic azide, an isocyanate, a phosphine, an amide, an ether, or a combination thereof. In the embodiment where the crosslinkable group 104 is a UV curable group, the crosslinkable group 104 includes at least one photosensitive functional group, for example, epoxy resin, azo compound, alkyl halide, imine, olefin, alkyne, peroxide, ketone, aldehyde, allene, aromatic group, or heterocyclic group. The aromatic structure can be phenyl, naphthlenyl, phenanthrenyl, anthracenyl, phenalenyl, and other aromatic derivatives containing three to ten rings.

[0025] Figure 2B Provided in Figure 2AA more detailed illustration of the polarity switchable group 106 in . The polarity switchable group 106 may include a first end group 1061 bonded to the polymer backbone 102, a second end group 1062, and an acid-labile group 1063 bonded to both the first end group 1061 and the second end group 1062. In some cases, the second end group 1062 has a hydrophobicity or chemical affinity (i.e., polarity) different from that of the polymer backbone 102 and the group bonded thereto. When the acid-labile group 1063 decomposes in the presence of an acidic moiety, the second end group 1062 may be released, thereby changing the "polarity" of the polymer backbone 102 and the group bonded thereto. In some embodiments, the first end group 1061 may be omitted, and the acid-labile group 1063 is bonded to the polymer backbone 102 and the second end group 1062 and is located between them, thereby allowing the second end group 1062 to cleave from the polymer backbone 102 in the presence of an acid. Although as an example, the acid-labile group 1063 is Figure 2B In the embodiment of the present invention, the second end group 1062 is shown as including a carboxyl bond, but in other embodiments, it can include a hydrazone bond, a carboxylic acid hydrazone bond, a ketal bond, an acetal bond, a siloxane bond, an aconite bond, an oxime bond, a silyl ether bond, or an anhydride. The second end group 1062 includes a fluorine atom or a fluorine-containing group (Fx), for example, a fluorocarbon group. Since the fluorine-containing group reduces the affinity for the photoresist layer to be deposited on the first bottom layer 204, whether the second end group 1062 is cut off from the polymer backbone 102 has a key influence on the affinity of the first bottom layer 204 to the photoresist. In some embodiments, the polarity switchable group 106 may include an ester, an amide, an imine, an acetal, a ketal, an anhydride, a sulfonate, a t-Butyl, a tert-Butoxycarbonyl, an iso-Norbornyl, a 2-methyl-2-adamantyl, a 2-ethyl-2-adamantyl, a 3-THF, a lactone, a 2-THF, a 2-THP group. In some embodiments, the polarity switchable group 106 may include a functional group, for example, -I, -Br, -Cl, -COOH, -OH, -SH, -N3, -S(=O)-, an alkene, an alkyne, acetic acid, a cyanide, or a propadiene. In order to illustrate and emphasize the function of the fluorine-containing group on the polarity switchable group 106 in the first bottom layer 204, Figure 4 as well as Figure 5-10 The fluorine-containing group is marked with reference numeral 206 in FIG.

[0026] In some embodiments, the polarity switchable group 106 can be obtained by chemically modifying the acid-labile group. The chemical modification includes attaching a fluorine-containing group (Fx) to the acid-labile group so that the fluorine-containing group and the polymer backbone are located on different sides of the acid-labile bond, which is cut in the presence of the acidic part. Note that the fluorine-containing group may not be bonded to a position adjacent to the acid-labile bond to avoid affecting the acid stability of the acid-labile bond. Examples of modified acid-labile groups include:

[0027]

[0028] The photoresist affinity groups 108 on the polymer backbone 102 help adjust the contact angle of the photoresist layer to be deposited on the first bottom layer 204. The contact angle of the photoresist layer relative to the surface of the first bottom layer 204 depends on the affinity of the photoresist layer to the first bottom layer 204. As described above, the presence of the fluorine-containing group on the second end group 1062 reduces the affinity between the first bottom layer 204 and the photoresist layer. In some embodiments, the photoresist affinity groups 108 provide a balance to the fluorine-containing groups. That is, the photoresist affinity groups 108 are designed to enhance the affinity to the photoresist layer. In some cases, the photoresist affinity groups 108 may have a cyclic or non-cyclic alkyl group containing between 1 and 30 carbon atoms. In order to enhance the affinity to the photoresist layer, the photoresist affinity group 108 may include a functional group, for example, -I, -Br, -Cl, -NH2, -COOH, -OH, -SH, -N3, -S(=O)-, olefin, alkyne, imine, ether, ester, aldehyde, ketone, amide, sulfone, acetic acid, or cyanide.

[0029] The photoacid generator 110 includes one or more chemical compounds that can decompose when exposed to a radiation source (at block 22) to generate one or more acidic moieties to cleave the acid-labile group 1063 and sever the second end group 1062 from the polymer backbone 102. In some embodiments, the photoacid generator 110 can include a benzene ring. In some embodiments, the photoacid generator 110 includes triazines, onium salts, diazonium salts, aromatic diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, o-nitrobenzylsulfonates, sulfonated esters, halogenated sulfonyloxy dicarboximides, diazodisulfones, α-cyanooxyamine sulfonates, imide sulfonates, ketodiazosulfones, sulfonyldiazoesters, 1,2-di(arylsulfonyl)hydrazines, nitrobenzyl esters, or other applicable materials. The additive 112 may include a surfactant that promotes uniform dispersion of the components of the first coating solution. In some embodiments, the additive may include more than one surfactant to satisfactorily disperse components of various molecular weights. Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan Sugar alcohol monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, polyethylene glycol distearate, polyethylene glycol dilaurate, polyethylene glycol dilaurate, polyethylene glycol, polypropylene glycol, polyoxyethylene stearyl ether, and polyoxyethylene cetyl ether; fluorinated cationic surfactants, fluorinated nonionic surfactants, fluorinated anionic surfactants, cationic surfactants and anionic surfactants, polyethylene glycol, polypropylene glycol, polyoxyethylene cetyl ether, combinations of these items, etc.

[0030] refer to Figure 1 and Figure 5, method 10 includes frame 16, wherein first bottom layer 204 is cured to form cured first bottom layer 208. In embodiments where crosslinkable groups 104 are heat crosslinkable groups, frame 16 includes a baking process to activate crosslinkable groups 104 to bond to another polymer backbone other than the polymer backbone to which crosslinkable groups 104 are bonded, or another crosslinkable group. In embodiments where crosslinkable groups 104 are UV curable groups, frame 16 includes a UV curing process to expose crosslinkable groups 104 to UV to activate crosslinkable groups 104 to bond to another polymer backbone other than the polymer backbone to which crosslinkable groups 104 are bonded, or another crosslinkable group. Figure 5 In the illustrated embodiment, the first bottom layer 204 is subjected to a baking process 1002 at a temperature between about 160° C. and about 250° C. to activate and cure the crosslinkable groups 104. Figure 5 Not shown, but fully contemplated by the present disclosure, is a UV curing process at block 16 to cure the first bottom layer 204 when the cross-linkable groups 104 in the first bottom layer 204 include UV curable groups.

[0031] refer to Figure 1 and Figure 6 The method 10 includes block 18, wherein a photoresist layer 210 is deposited over the cured first bottom layer 208. The photoresist layer 210 may be an organic chemically amplified photoresist (CARs) layer, an inorganic photoresist, or an organometallic photoresist layer. Figure 6 In the illustrated embodiment, the photoresist layer 210 is an organometallic photoresist that includes a metal such as tin, zirconium, palladium, cobalt, nickel, chromium, iron, rhodium, or ruthenium. For example, the photoresist layer 210 may include a tin-oxygen cage compound, such as [(SnBu) 12 O 14 (OH)6](OH)2. In some embodiments, the photoresist layer 210 is deposited directly on the cured first bottom layer 208 using spin coating. The photoresist layer 210 is a negative photoresist that can undergo a chemical change during the exposure process to become insoluble in a developer solution during the development process. For example, the photoresist layer 210 can include a photoacid generator that generates an acid when exposed to catalyze crosslinking to make the photoresist layer 210 insoluble in a developer solution.

[0032] refer to Figure 1 and Figure 7 , method 10 includes block 20, wherein a pre-exposure baking process 1004 is performed. The pre-exposure baking process 1004 may also be referred to as a post-application baking process 1004. In some embodiments, Figure 7The temperature of the pre-exposure bake process 1004 is shown to be between about 60° C. and about 170° C. The pre-exposure bake process 1004 may drive off excess solvent in the photoresist layer 210 and cure the photoresist layer 210 .

[0033] refer to Figure 1 and Figure 8 , method 10 includes block 22, wherein a portion of photoresist layer 210 is exposed to radiation source 1006 according to the pattern of mask 1008. Figure 8 Mask 1008 is shown as a transmissive mask commonly used with an ArF (argon fluoride) excimer laser radiation source or a KrF (krypton fluoride) excimer laser radiation source, but the embodiments of the present disclosure are fully applicable to lithography systems including reflective masks commonly used with EUV radiation sources. Similarly, radiation source 1006 can be an ArF excimer laser radiation source, a KrF excimer laser radiation source, or an EUV radiation source. Figure 8 Schematically shown in FIG, mask 1008 includes a pattern so that only portion 212 of photoresist layer 210 and portion 214 of cured first bottom layer 208 are exposed to radiation from radiation source 1006. The radiation at frame 22 not only causes chemical changes in photoresist layer 210, but also activates photoacid generator 110 to release acidic moieties. Note that although the above-mentioned acid-labile groups 1063 can be chemically cleaved in the presence of acidic moieties, the cleavage reaction may not occur at room temperature. In some embodiments, the cleavage reaction occurs substantially during the post-exposure baking process at frame 24. In embodiments where photoresist layer 210 includes an inorganic photoresist or an organometallic photoresist, the chemical changes caused by exposure at frame 22 may not require a post-exposure baking process to promote further chemical reactions. In contrast, in embodiments where photoresist layer 210 includes an organic photoresist, the chemical changes caused by exposure at frame 22 may include releasing acidic moieties from the photoacid generator, and a post-exposure baking process is required to cause crosslinking.

[0034] refer to Figure 1 and Fig. 9, the method 10 includes a block 24, wherein a post-exposure baking process 1010 is performed. The acid-labile groups 1063 of the polarity-convertible groups 106 may be decomposed in the presence of the acidic moiety released from the photoacid generator 110 during the post-exposure baking process 1010. In some embodiments, the baking temperature or baking temperature profile of the post-exposure baking process 1010 is selected to ensure that the acid-labile groups 1063 may be decomposed to cut off the second end groups 1062 from the polymer backbone 102 of the cured first bottom layer 208. In some embodiments, the second end groups 1062 have a small molecular weight and are removed from the first bottom layer by outgassing during the post-exposure baking process 1010. Since the second end groups 1062 include fluorine-containing groups 206, which reduce affinity with the photoresist layer 210, once the second end groups 1062 in the exposed portion 214 are removed, the affinity of the photoresist layer 210 to the exposed portion 214 of the cured first bottom layer 208 increases. In contrast, since the fluorine-containing groups 206 are still present in the unexposed portions 215 of the cured first bottom layer 208, the affinity of the photoresist 210 to the unexposed portions 215 is weaker than the affinity of the photoresist layer 210 to the exposed portions 214 of the cured first bottom layer 208. The reduced affinity of the unexposed portions 215 due to the presence of the fluorine-containing groups 206 can facilitate the removal of the photoresist layer 210 from the unexposed portions 215 at block 216.

[0035] refer to Figure 1 and Fig.10 , the method 10 includes block 26, wherein the exposed portions 212 of the photoresist layer 210 are developed in a developing process 1012 to form a patterned photoresist layer 216. In some embodiments, the developing process 1012 may include using a developer solution that is easily adapted to remove the unexposed photoresist 210 while the exposed portions 212 of the photoresist layer 210 remain on the cured first bottom layer 208. Since the exposed portions 212 remain after the developing process 1012 and the unexposed portions are removed, Fig.10The development process 1012 shown can be referred to as a negative tone development (NTD) process. When the photoresist layer 210 is organic, a suitable negative tone developer may include a solvent, such as n-butyl acetate, ethanol, hexane, benzene, toluene, and / or other suitable solvents, and when the photoresist layer 210 is inorganic or organometallic, a suitable negative tone developer may include water, isopropyl alcohol (IPA), 2-heptanone, or a mixture thereof. In some embodiments, frame 26 may also include one or more slag removal or rinsing processes to remove any residual photoresist layer 210 or debris. In all of these slag removal or rinsing processes, the affinity of the unexposed portion 215 (to the photoresist layer 210) reduced by the presence of the fluorine-containing group 206 helps to remove the photoresist layer 210 from the unexposed portion 215 at frame 26, thereby reducing scum, improving the process window, and increasing process yield. Note that the unexposed portion 215 of the cured first bottom layer 208 remains on the substrate 202.

[0036] refer to Figure 1 , method 10 includes block 28, wherein substrate 202 is etched using photoresist layer 216 as an etching mask. In some embodiments, substrate 202 and cured first bottom layer 208 are both etched by a dry etching process (e.g., a reactive ion etching (RIE) process) using patterned photoresist layer 216 as an etching mask. In some examples, the dry etching process may be performed using an etchant gas including: a fluorine-containing etchant gas (e.g., NF3, CF4, SF6, CH2F2, CHF3, and / or C2F6), an oxygen-containing gas (e.g., O2), a chlorine-containing gas (e.g., Cl2, CHCl3, CCl4, SiCl4, and / or BCl3), a bromine-containing gas (e.g., HBr and / or CHBr3), an iodine-containing gas, other suitable gases and / or plasmas, or combinations thereof. Substrate 202 may include a material layer as the topmost layer of substrate 202, and the material layer is etched and patterned at block 28 to form a patterned material layer. In some embodiments, the material layer may be a spin-on carbon (SOC) layer.

[0037] refer to Figure 1, the method 10 includes a block 30, wherein further processing is performed. Such further processing may include removing the residual photoresist layer 210 from above the patterned material layer by stripping, and the patterned material layer is used as an etching mask to etch other layers and structures below the material layer. Further processing may be performed to form various passive and active microelectronic devices, such as resistors, capacitors, inductors, diodes, metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), laterally diffused MOS (LDMOS) transistors, high power MOS transistors, other types of transistors, and / or other circuit elements on the workpiece 200.

[0038] The operation of method 10 will be referred to below as follows Figure 12-27 When using the Fig.11 The second coating solution 300 of the composition shown in FIG. 1 is used to form a second bottom layer. The second coating solution 300 can be used to form a second bottom layer suitable for a positive tone development (PTD) process or an NTD process. Figure 12-19 An example NTD process using the second coating solution 300 is shown in FIG. Figure 20-27 An example PTD process using a second coating solution is shown in FIG.

[0039] refer to Figure 1 and Fig.12 , the method 10 includes block 12, in which a substrate 402 is received. The substrate 402 is substantially similar to the substrate 202, and a description thereof is omitted.

[0040] Reference now Figure 1 , Fig.11 and Fig.13 , method 10 includes block 14, wherein a second bottom layer 404 is formed over substrate 402. In some embodiments, second bottom layer 404 may be formed using Fig.11The second coating solution 300 schematically shown is spin-coated on a bottom anti-reflective coating (BARC) layer on a substrate 402. Similar to the first coating solution 100, the second coating solution 300 includes a solvent 101, a polymer backbone 102, a photoresist affinity group 108, a photoacid generator 110, and an additive 112. Unlike the first coating solution 100, the second coating solution 300 includes a fluorine-containing group 302 directly bonded to the polymer backbone 102, a polar group 304 directly bonded to the polymer backbone 102, a crosslinker 306, and a thermal acid generator (TAG) 308. The description of the solvent 101, the polymer backbone 102, the photoresist affinity group 108, the photoacid generator 110, and the additive 112 has been described above in conjunction with the first coating solution 100 and will not be repeated here.

[0041] In order to illustrate the function of the fluorine-containing group 302, Figure 11-19 The fluorine-containing group 302 is labeled and described in FIG. In terms of composition, the fluorine-containing group 302 can be substantially similar to the fluorine-containing group 206 described above. Instead of being bonded to the polymer backbone 102 via the acid-labile group 1063, the fluorine-containing group 302 is directly bonded to the polymer backbone 102. As a result, the fluorine-containing group 302 will not be Fig.10 The polar group 304 may include a functional group that can react with the crosslinking agent 306 (when there is an acidic part to catalyze such a reaction). In some embodiments, the polar group 304 may include a cyclic or non-cyclic alkyl backbone having 1 to 30 carbon atoms. The polar group 304 may include a functional group, for example, -I, -Br, -Cl, -NH2, -COOH, -OH, -SH, -N3, -S(=O)-, olefins, alkynes, imines, ethers, esters, aldehydes, ketones, amides, sulfones, acetic acid, cyanide, allene, alcohols, diols, amines, phosphine, phosphites, anilines, pyridines, pyrroles, or combinations thereof. The crosslinking agent 306 includes a functional group that can be catalyzed by an acidic part to crosslink with the polar group 304. The thermal acid generator 308 includes one or more functional groups that can generate an acidic part when baked at a suitable temperature. Examples of thermal acid generators 308 may include:

[0042] NH4 + C4F9SO3 - NH4 + CF3SO3 -

[0043]

[0044] refer to Figure 1 and Fig.14, method 10 includes block 16, wherein second bottom layer 404 is cured to form cured second bottom layer 408. Fig.14 In the illustrated embodiment, the second bottom layer 404 is cured using a baking process 1002 that includes a temperature between about 160° C. and about 250° C. At block 16, the baking process 1002 activates the thermal acid generator 308 to generate an acidic moiety. The acidic moiety catalyzes a reaction between the crosslinking agent 306 and the polar groups 304 bonded to the polymer backbone 102, thereby curing the second bottom layer 404 to form a cured second bottom layer 408.

[0045] refer to Figure 1 and Fig.15 , method 10 includes frame 18, wherein a photoresist layer 412 is deposited over the cured second bottom layer 408. The photoresist layer 412 can be a positive photoresist that can undergo a chemical change during an exposure process to become soluble in a developer during a development process. For example, the photoresist layer 412 can include a photoacid generator that generates an acid when exposed to light to cleave acid-labile groups to make the photoresist layer 412 soluble in an aqueous developer solution. The photoresist layer can be a negative photoresist that can undergo a chemical change during an exposure process to become insoluble in a developer solution during a development process. For example, the photoresist layer 412 can include a photoacid generator that generates an acid when exposed to light to catalyze crosslinking to make the photoresist layer 412 insoluble in a developer solution. In Figure 15-19 In the illustrated embodiment, the photoresist layer 412 is a negative photoresist layer.

[0046] refer to Figure 1 and Fig.16 , the method 10 includes block 20, wherein a pre-exposure bake process 1004 is performed. During the pre-exposure bake process 1004, excess solvent in the photoresist layer 412 is removed.

[0047] refer to Figure 1 and Fig.17, method 10 includes frame 22, wherein a portion of photoresist layer 412 is exposed to radiation source 1006 according to the pattern of mask 1008. Descriptions of radiation source 1006 and mask 1008 have been provided above and are not repeated here. Note again that since fluorine-containing groups 302 are directly bonded to polymer backbone 102, exposure to radiation from radiation source 1006 does not trigger any cleavage reaction to remove fluorine-containing groups 302 from cured second bottom layer 408. In embodiments where negative photoresist layer 412 comprises an inorganic photoresist or an organometallic photoresist, the chemical changes caused by exposure at frame 22 may not require a post-exposure bake process to drive further chemical reactions. In contrast, in embodiments where negative photoresist layer 412 comprises an organic photoresist, the chemical changes caused by exposure at frame 22 may include the release of acidic moieties from a photoacid generator, and a post-exposure bake process is required to generate acidic moieties to cause crosslinking.

[0048] refer to Figure 1 and Fig.18 , method 10 includes frame 24, wherein a post-exposure bake process 1010 is performed. In some embodiments, the post-exposure bake process 1010 has no substantial effect on the cured second bottom layer 408, because the exposure process at frame 22 does not produce any chemical substances to initiate any further chemical reactions. In those embodiments, the necessity of performing the post-exposure bake process 1010 depends on whether it is needed to drive further reactions in the exposed portion 414 of the photoresist layer 412. In the case where the photoresist layer 412 includes an inorganic photoresist or an organometallic photoresist, the post-exposure bake process 1010 can be omitted because the chemical changes in the photoresist layer 412 do not require thermal energy input. In the case where the photoresist layer 412 includes an organic photoresist, the post-exposure bake process 1010 may be required because the acidic or basic portions produced at frame 22 may require thermal energy to cause crosslinking.

[0049] refer to Figure 1 and Fig.19 , method 10 includes block 26, wherein the exposed portions 414 of the photoresist layer 412 are developed in a development process 1012 to form a patterned photoresist layer 416. In some embodiments, the development process 1012 may include using a developer solution that is suitable for removing the unexposed portions of the photoresist layer 412 while the exposed portions 414 of the photoresist layer 412 remain on the cured second bottom layer 408. Because the exposed portions 414 remain after the development process 1012 and the unexposed portions are removed, Fig.19The development process 1012 shown can be referred to as an NTD process. When the photoresist layer 210 is organic, a suitable negative developer can include a solvent, such as n-butyl acetate, ethanol, hexane, benzene, toluene, and / or other suitable solvents, and when the photoresist layer 210 is inorganic or organometallic, a suitable negative developer can include water, isopropyl alcohol (IPA), 2-heptanone, or a mixture thereof. In some embodiments, frame 26 can also include one or more descum or rinse processes to remove any residual photoresist layer 412 or debris. In all of these descum or rinse processes, the affinity of the cured second bottom layer 408 (to the photoresist layer 412) reduced by the presence of the fluorine-containing groups 302 helps to remove the residual photoresist layer 412 from the cured second bottom layer 408 at frame 26, thereby reducing scum, improving process window and increasing process yield. Note that the unexposed portion of the cured second bottom layer 408 remains on the substrate 402.

[0050] refer to Figure 1 , method 10 includes frame 28, wherein the substrate 402 is etched using the photoresist layer 416 as an etching mask. In some embodiments, the substrate 402 and the cured second bottom layer 408 are both etched by a dry etching process (e.g., a reactive ion etching (RIE) process) using the patterned photoresist layer 416 as an etching mask. In some examples, the dry etching process can be performed using an etchant gas including the following items: a fluorine-containing etchant gas (e.g., NF3, CF4, SF6, CH2F2, CHF3, and / or C2F6), an oxygen-containing gas (e.g., O2), a chlorine-containing gas (e.g., Cl2, CHCl3, CCl4, SiCl4, and / or BCl3), a bromine-containing gas (e.g., HBr and / or CHBr3), an iodine-containing gas, other suitable gases and / or plasmas, or a combination thereof. In some embodiments, the substrate 402 may include a material layer as the topmost layer of the substrate 402, and the material layer is etched and patterned at frame 28 to form a patterned material layer. In some embodiments, the material layer may be a spin-on carbon (SOC) layer.

[0051] refer to Figure 1, method 10 includes block 30, wherein further processing is performed. Such further processing may include removing residual photoresist layer 412 from above the patterned material layer by stripping, and the patterned material layer is used as an etching mask to etch other layers and structures below the material layer. Further processing may be performed to form various passive and active microelectronic devices, such as resistors, capacitors, inductors, diodes, metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), laterally diffused MOS (LDMOS) transistors, high power MOS transistors, other types of transistors, and / or other circuit elements on the workpiece 400.

[0052] The second coating solution 300 can be used to form the second bottom layer 504 in a PTD process, in which the pattern of the mask 1008 is transferred to the positive photoresist layer 512 ( Fig.23 ), instead of the negative photoresist layer 412. The method 10 may be implemented using the positive photoresist layer 512 and the second coating solution 300, and the following is combined with Figure 20-27 Describe the operation.

[0053] refer to Figure 1 and 20 , method 10 includes block 12, in which a substrate 502 is received. Substrate 502 is substantially similar to substrate 202, and a description thereof is omitted. Substrate 502 and any layers formed thereon may be referred to as workpiece 500. Figure 1 , Fig.11 and Fig.21 , method 10 includes block 14, wherein a second bottom layer 504 is formed over substrate 502. Second bottom layer 504 is substantially similar to second bottom layer 404, and a description thereof is omitted. Figure 1 and Fig. 22 , method 10 includes block 16, wherein second bottom layer 504 is cured in a baking process 1002 to form a cured second bottom layer 508. The description of the curing of second bottom layer 504 and baking process 1002 has been described above with respect to second bottom layer 404 and will not be repeated here. Figure 1 and Fig.23 , method 10 includes block 18, wherein a photoresist layer 512 is deposited over the cured second bottom layer 508. The photoresist layer 512 is a positive photoresist layer and may be deposited using spin coating. Figure 1 and Fig.24The method 10 includes a block 20 in which a pre-exposure bake process 1004 is performed to make the positive photoresist layer 512 soluble in a developer solution. Unlike the negative photoresist layer 412, the photoresist layer 512 may include a photoacid generator that may generate an acidic portion to cleave an acid-labile group to change the hydrophobicity of the photoresist layer 512.

[0054] refer to Figure 1 and Fig.25 , method 10 includes box 22, wherein a portion 514 of the photoresist layer 512 is exposed to a pattern of radiation. A description of the radiation source 1006 and the mask 1008 has been provided above and will not be repeated here. Note again that because the fluorine-containing groups 302 are directly bonded to the polymer backbone 102, exposure to radiation from the radiation source 1006 does not trigger any cleavage reaction to remove the fluorine-containing groups 302 from the cured second bottom layer 508. In embodiments in which the positive photoresist layer 512 comprises an inorganic photoresist or an organometallic photoresist, the chemical changes caused by the exposure at box 22 may not require a post-exposure bake process to drive further chemical reactions. In contrast, in embodiments in which the positive photoresist layer 512 comprises an organic photoresist, the chemical changes caused by the exposure at box 22 may include the release of acidic moieties from a photoacid generator, and a post-exposure bake process is required to generate acidic moieties to change the solubility of the positive photoresist layer 512. Reference Figure 1 and Fig.26 , the method 10 includes a block 24, in which a post-exposure bake process 1010 is performed. The necessity of performing the post-exposure bake process 1010 depends on whether it is needed to drive further reactions in the exposed portions 514 of the photoresist layer 512. In the case where the photoresist layer 512 includes an inorganic photoresist or an organometallic photoresist, the post-exposure bake process 1010 can be omitted because the chemical changes in the photoresist layer 512 do not require thermal energy input. In the case where the photoresist layer 512 includes an organic photoresist, the post-exposure bake process 1010 may be required because the acidic moieties generated at block 22 may require thermal energy to make the exposed portions 514 soluble in the developer to be used at block 26.

[0055] refer to Figure 1 and Fig. 27, method 10 includes frame 26, wherein the exposed portion 514 of the photoresist layer 512 is developed in a development process 1012 to form a patterned photoresist layer 516. In some embodiments, the development process 1012 may include using a developer solution that is suitable for removing the exposed portion 514 of the positive photoresist layer 512, while the unexposed portion of the photoresist layer 412 remains on the cured second bottom layer 508. Suitable positive developers include tetramethylammonium hydroxide (TMAH), KOH, NaOH, and / or other suitable solvents. In some embodiments, frame 26 may also include one or more descum or rinse processes to remove any residual photoresist layer 512 or debris. In all of these descum or rinse processes, the reduced affinity of the cured second bottom layer 508 (to the photoresist layer 512) due to the presence of the fluorine-containing groups 302 facilitates the removal of any residual photoresist layer 512 from the cured second bottom layer 508 at block 26, thereby reducing scum, improving the process window, and increasing process yields. Note that the exposed portions of the cured second bottom layer 508 remain on the substrate 502.

[0056] refer to Figure 1 , method 10 includes frame 28, wherein the substrate 502 is etched using the patterned photoresist layer 516 as an etching mask. In some embodiments, both the substrate 502 and the cured second bottom layer 508 are etched by a dry etching process (e.g., a reactive ion etching (RIE) process) using the patterned photoresist layer 516 as an etching mask. Suitable dry etchants have been described above and are not repeated here. In some embodiments, the substrate 502 may include a material layer as the topmost layer of the substrate 502, and the material layer is etched and patterned at frame 28 to form a patterned material layer. In some embodiments, the material layer may be a spin-on carbon (SOC) layer. Reference Figure 1 , method 10 includes block 30, wherein further processing is performed. Such further processing may include removing the residual photoresist layer 512 from above the patterned material layer by stripping, and the patterned material layer is used as an etching mask to etch other layers and structures below the material layer. Further processing has been described above and will not be repeated here.

[0057] The operation of method 10 will be referred to below as follows Figure 29-37 When using the Fig.28 A cross-sectional view of a workpiece 700 when the composition of the third coating solution 600 is used to form a third bottom layer will be described.

[0058] refer to Figure 1 and Fig.29, the method 10 includes block 12, in which a substrate 702 is received. The substrate 702 is substantially similar to the substrate 202, and a description thereof is omitted.

[0059] refer to Figure 1 , Fig.28 and Fig.30 The method 10 includes block 14, wherein a third bottom layer 704 is formed over the substrate 702. In some embodiments, the third bottom layer 704 may be formed using Fig.28 1 and 2. The third coating solution 600 schematically shown in FIG. 1 is a bottom anti-reflective coating (BARC) layer spin-coated on the substrate 702. Similar to the second coating solution 300, the third coating solution 600 includes a solvent 101, a polymer backbone 102, a photoresist affinity group 108, an additive 112, a polar group 304, and a thermal acid generator 308. Different from the second coating solution 300, the third coating solution 600 includes an acid-labile group 602 bonded to the polymer backbone 102, a UV-curable group 604 bonded to the polymer backbone 102, and a photobase generator 606. That is, the acid-labile group 602 serves as a bridge between the polymer backbone 102 and the UV-curable group 604. The description of the solvent 101, the polymer backbone 102, the photoresist affinity group 108, the photoacid generator 110, the additive 112, the polar group 304 and the thermal acid generator 308 has been described above in conjunction with the first coating solution 100 and the second coating solution 300 and will not be repeated here.

[0060] The acid-labile group 602 can be cleaved in the presence of an acidic part, thereby cutting off the UV curable group from the polymer backbone 102. The acidic part can be generated by the activation of a thermal acid generator 308. The UV curable group 604 is used to crosslink to another UV curable group or another polymer backbone, and the cleavage of the acid-labile group 602 also decouples the crosslinking. The acid-labile group 602 can have a cyclic structure or a non-cyclic alkyl structure, and can include an aromatic ring or a non-aromatic ring. In some embodiments, the acid-labile group 602 may include: ester, amide, imine, acetal, ketal, anhydride, sulfonate, tert-butyl, tert-butyloxycarbonyl, iso-norbornyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl, 3-THF, lactone, 2-THF, or 2-THP. The acid-labile group 602 may include a functional group, for example, -I, -Br, -Cl, -NH2, -COOH, -OH, -SH, -N3, -S(=O)-, olefin, alkyne, imine, ether, vinyl ether, acetal, hemiacetal, ester, aldehyde, ketone, amide, sulfone, acetic acid, cyanide, allene, or imine.

[0061] UV curable group 604 may include an alkyl backbone with 3 to 30 carbon atoms. In certain embodiments, UV curable group 604 includes at least one photosensitive functional group, for example, epoxy resin, azo compound, alkyl halide, imine, olefin, alkyne, peroxide, ketone, aldehyde, allene, aromatic group or heterocyclic group. Aromatic structure can be phenyl, naphthyl, phenanthrenyl, anthracenyl, phenoxyl and other aromatic derivatives containing three to ten rings. When exposed to UV, one or more free radicals can be formed on UV curable group 604, allowing it to be bonded to another UV curable group or another polymer backbone by free radical polymerization.

[0062] The photobase generator 606 can be photosensitive and can decompose to provide a basic moiety when exposed to radiation in a suitable wavelength range. Non-limiting examples of PBGs provided herein include the following structures:

[0063]

[0064] refer to Figure 1 and Fig.31 , method 10 includes block 16, wherein the third bottom layer 704 is cured to form a cured third bottom layer 706. When the third bottom layer 704 is formed using the third coating solution 600, the third bottom layer 704 is cured using a UV curing process 1022. The UV radiation at the UV curing process 1022 activates the UV curable groups 604 to form crosslinks, thereby curing the third bottom layer 704. Note that the acid-labile groups 602 remain inactive at block 16 because the acid-labile groups 602 are not sensitive to UV. It should also be noted that the third coating solution 600 does not include any photoacid generator that can generate an acidic moiety to cleave the acid-labile groups 602.

[0065] refer to Figure 1 and Fig.32 , method 10 includes frame 18, wherein a photoresist layer 708 is deposited over the cured third bottom layer 706. The photoresist layer 708 is a negative photoresist. When the photoresist layer 708 is organic, a suitable negative developer may include a solvent, for example, n-butyl acetate, ethanol, hexane, benzene, toluene, and / or other suitable solvents, and when the photoresist layer 708 is inorganic or organometallic, a suitable negative developer may include water, isopropyl alcohol (IPA), 2-heptanone, or a mixture thereof. The photoresist layer 708 may be an organic chemically amplified photoresist (CARs) layer, an inorganic photoresist, or an organometallic photoresist layer. In Fig.32In the illustrated embodiment, the photoresist layer 708 is an organometallic photoresist that includes a metal such as tin, zirconium, palladium, cobalt, nickel, chromium, iron, rhodium, or ruthenium. For example, the photoresist layer 708 may include a tin-oxygen cage compound, such as [(SnBu) 12 O 14 (OH)6](OH)2. In some embodiments, the photoresist layer 708 is deposited directly on the cured third bottom layer 706 using spin coating.

[0066] refer to Figure 1 and Fig.33 , the method 10 includes block 20, wherein a low temperature bake process 1014 is performed. In some embodiments, the temperature of the low temperature bake process 1014 is selected so that the acid labile groups 602 are not cleaved by the operation of thermal energy on the thermal acid generator 308. That is, the temperature of the low temperature bake process 1014 is below a threshold temperature for decomposing the thermal acid generator 308. In some embodiments, the temperature of the low temperature bake process 1014 is between about 60° C. and about 150° C., and the threshold temperature for decomposing the thermal acid generator 308 is about 160° C.

[0067] refer to Figure 1 and Fig.34 , method 10 includes frame 22, wherein, part 712 of photoresist layer 708 is exposed to the pattern of radiation. The description of radiation source 1006 and mask 1008 has been provided above, and will not be repeated here. As mentioned above, photoresist layer 708 is a negative photoresist layer. In the embodiment where negative photoresist layer 708 includes inorganic photoresist or organometallic photoresist, the chemical change caused by the exposure at frame 22 may not need a post-exposure baking process to drive further chemical reactions. On the contrary, in the embodiment where negative photoresist layer 708 includes organic photoresist, the chemical change caused by the exposure at frame 22 may include releasing acidic parts from photoacid generator, and a post-exposure baking process is needed to generate acidic parts to cause crosslinking. At frame 22, part 714 of the cured third bottom layer 706 is also exposed to radiation from radiation source 1006. The radiation decomposes the photobase generator 606 in the exposed portion 714 of the cured third bottom layer 706 to generate a basic portion 716 in the cured third bottom layer 706 .

[0068] refer to Figure 1 , Fig.35 and Fig.36 The method 10 includes block 24, wherein a post-exposure bake process 1010 is performed. The temperature of the post-exposure bake process 1010 is selected to be greater than a threshold temperature to decompose the thermal acid generator 308 to provide the acidic portion 718, such as Fig.35As shown. In some embodiments, the temperature of the post-exposure bake process 1010 is between about 160°C and about 250°C. In embodiments where the photoresist layer 708 comprises an inorganic photoresist or an organometallic photoresist, the chemical changes caused by the exposure at frame 22 may not require a post-exposure bake process to drive further chemical reactions. In contrast, in embodiments where the photoresist layer 708 comprises an organic photoresist, the chemical changes caused by the exposure at frame 22 may include releasing acidic moieties from the photoacid generator, and a post-exposure bake process 1010 is required to generate the acidic moieties to cause crosslinking. As shown Fig.35 As shown, the acidic moieties 718 in the exposed portions 714 of the cured third bottom layer 706 are neutralized by the alkaline moieties 716 generated in frame 22, while the acidic moieties 718 in the unexposed portions 720 of the cured third bottom layer 706 do not encounter any alkaline moieties 716. In some embodiments, substantially all of the acidic moieties 718 in the exposed portions 714 of the cured third bottom layer 706 are neutralized, leaving no acidic moieties 718 to cleave the acid-labile groups 602 during the post-exposure bake process 1010. In some other embodiments, the amount of the acidic moieties 718 in the exposed portions 714 is reduced to a level substantially less than the amount of the acidic moieties 718 in the unexposed portions 720. Fig.36 As shown, the acidic moieties 718 can decompose the acid labile groups 602, resulting in decoupling of the crosslinking that may occur with the UV curable groups 604. Decrosslinking in the unexposed portions 720 converts the unexposed portions 720 into converted portions 722, which can be removed in the development process at block 26. Due to the lack of acidic moieties 718 or the reduced amount of acidic moieties 718 in the exposed portions 714, the exposed portions 714 cannot be removed in the development process at block 26.

[0069] refer to Figure 1 and Fig.37 , method 10 includes frame 26, wherein the exposed portions of photoresist layer 708 are developed in a development process 1012 to form a patterned photoresist layer 724. Fig.37 As shown, the development process 1012 includes using a developer selected to dissolve the unexposed portions of the photoresist layer 708 and the converted portions 722 of the cured third bottom layer 706, thereby exposing the top surface of the substrate 702. The developer can remove the unexposed portions of the photoresist layer 708 because the unexposed portions are not cross-linked. The developer can remove the converted portions 722 because they have been de-cross-linked by the operation of the acidic portion 718 and the thermal energy of the post-exposure bake process 1010.

[0070] refer to Figure 1, method 10 includes frame 28, wherein the substrate 702 is etched using the patterned photoresist layer 724 as an etching mask. In some embodiments, the substrate 702 is etched by a dry etching process (e.g., a reactive ion etching (RIE) process) using the patterned photoresist layer 724 as an etching mask. Suitable dry etchants have been described above and are not repeated here. In some embodiments, the substrate 702 may include a material layer as the topmost layer of the substrate 702, and the material layer is etched and patterned at frame 28 to form a patterned material layer. In some embodiments, the material layer may be a spin-on carbon (SOC) layer.

[0071] refer to Figure 1 , method 10 includes block 30, wherein further processing is performed. Such further processing may include removing residual photoresist layer 708 from above the patterned material layer by stripping, and the patterned material layer is used as an etching mask to etch other layers and structures below the material layer. Still further processing may be performed to form various passive and active microelectronic devices, such as resistors, capacitors, inductors, diodes, metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), laterally diffused MOS (LDMOS) transistors, high power MOS transistors, other types of transistors, and / or other circuit elements on the workpiece 700.

[0072] Although not intended to be limiting, one or more embodiments of the present disclosure provide many benefits for semiconductor devices and their formation processes. For example, the present disclosure discloses a coating solution for depositing a bottom layer that reduces scum formation, and a method for depositing a bottom layer using the disclosed coating solution. In some embodiments, the first bottom layer formed using the first coating solution includes a fluorine-containing group that can be cracked after exposure to a radiation source. Since the fluorine-containing group reduces the affinity between the photoresist layer and the first bottom layer, less residual photoresist material or scum will remain on the first bottom layer after the exposed photoresist layer is developed. In some other embodiments, the second bottom layer formed using the second coating solution includes a permanently bonded fluorine-containing group. Since the fluorine-containing group reduces the affinity between the photoresist layer and the second bottom layer, less residual photoresist material or scum will remain after the exposed photoresist layer is developed. In some other embodiments, the third bottom layer formed using the third coating solution includes a photobase generator and a thermal acid generator. Since the unexposed third bottom layer can be selectively removed together with the unexposed photoresist in a negative tone development (NTD) process, less residual photoresist material or scum may remain after the exposed photoresist layer is developed. By reducing the amount of residual photoresist / scum, the embodiments of the present disclosure expand the process window and improve the yield.

[0073] The present disclosure provides methods for forming semiconductor devices and embodiments of components of a bottom layer used with the disclosed methods. In one embodiment, a method is provided. The method includes: providing a substrate; depositing a bottom layer over the substrate, the bottom layer including: a polymer backbone; a polarity switchable group including: an acid-labile group bonded to a first end group of the polymer backbone, a second end group including fluorine, and a bonded between the first end group and the second end group; a crosslinkable group bonded to the polymer backbone; and a photoacid generator; depositing a photoresist layer over the bottom layer; exposing a portion of the photoresist layer and a portion of the bottom layer to a radiation source according to a pattern, thereby decomposing the photoacid generator in the exposed portion of the bottom layer to produce an acidic portion; baking the photoresist layer and the bottom layer so that the acidic portion reacts with the acid-labile group to separate the second end group from the polymer backbone; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer.

[0074] In certain embodiments, the deposition of the photoresist layer includes directly depositing the photoresist layer on the bottom layer. In some embodiments, the method also includes: before depositing the photoresist layer, baking the deposited bottom layer to activate the crosslinkable group to bond to another polymer backbone. In certain embodiments, the method includes: before depositing the photoresist layer, exposing the deposited bottom layer to ultraviolet (UV) source to activate the crosslinkable group to bond to another polymer backbone. In certain embodiments, the radiation source includes ArF excimer laser, KrF excimer laser or extreme ultraviolet (EUV) radiation source. In some cases, the photoresist layer is an organic metal photoresist, which includes a metal selected from the group consisting of: tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium. In some embodiments, the bottom layer also includes a photoresist-affinity group bonded to the polymer backbone, the photoresist-affinity group including between 1 and 30 carbon atoms, and the affinity between the photoresist layer and the photoresist-affinity group is greater than the affinity between the photoresist layer and the second end group of the polarity-switchable group.

[0075] In another embodiment, a method is provided. The method includes: providing a substrate; depositing an underlayer over the substrate, the underlayer including: a polymer backbone; a fluorine-containing group bonded to the polymer backbone; a polar group bonded to the polymer backbone; a thermally crosslinkable group bonded to the polymer backbone; a crosslinker; and a thermal acid generator including an acidic portion configured to catalyze bonding between the polar group and the crosslinker; depositing a photoresist layer over the underlayer; exposing a portion of the photoresist layer to a radiation source according to a pattern; baking the photoresist layer; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer.

[0076] In certain embodiments, the deposition of the photoresist layer comprises that the photoresist layer is directly deposited on the bottom layer. In certain embodiments, the method also comprises: before the deposition of the photoresist layer, the deposited bottom layer is baked to activate the thermal acid generator to release the acidic part for bonding polar groups and crosslinking agents. In some embodiments, the radiation source comprises an ArF excimer laser, a KrF excimer laser or an extreme ultraviolet (EUV) radiation source. In certain embodiments, the photoresist layer is an organic metal photoresist, which comprises a metal selected from the group consisting of: tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium. In some cases, the bottom layer also comprises a photoresist affinity group bonded to the polymer backbone, the photoresist affinity group comprises between 1 and 30 carbon atoms, and the affinity between the photoresist layer and the photoresist affinity group is greater than the affinity between the photoresist layer and the fluorine-containing group.

[0077] In another embodiment, a method is provided. The method includes: providing a substrate; depositing a bottom layer over the substrate, the bottom layer including: a polymer backbone; an acid-labile group bonded to the polymer backbone; an ultraviolet (UV) curable group bonded to the acid-labile group; a thermal acid generator configured to release an acidic portion at a first temperature; and a photobase generator configured to release a basic portion when exposed to a radiation source; depositing a photoresist layer over the bottom layer; baking the photoresist layer at a second temperature lower than the first temperature; exposing a portion of the photoresist layer and a portion of the bottom layer to the radiation source according to a pattern, thereby releasing the basic portion from the photobase generator; baking the bottom layer at the first temperature, thereby releasing the acidic portion to neutralize the basic portion; and developing the exposed portion of the photoresist layer and the exposed portion of the bottom layer to transfer the pattern to the photoresist layer and the bottom layer.

[0078] In some embodiments, depositing a photoresist layer includes depositing the photoresist layer directly on the bottom layer. In some embodiments, the photoresist layer is an organic metal photoresist, which includes a metal selected from the group consisting of: tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium. In some embodiments, the method also includes: before depositing the photoresist layer, the deposited bottom layer is exposed to an ultraviolet (UV) source to activate the UV curable group to bond to another polymer backbone. In some embodiments, the first temperature is between about 160°C and about 250°C. In some cases, the second temperature is between about 60°C and about 150°C. In some embodiments, the radiation source includes an ArF excimer laser, a KrF excimer laser, or an extreme ultraviolet (EUV) radiation source.

[0079] The features of several embodiments are summarized above so that those skilled in the art can better understand the various 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 purpose of the embodiments introduced herein and / or achieve the same advantages of the embodiments introduced 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 they can make various changes, substitutions and modifications herein without departing from the spirit and scope of the present disclosure.

[0080] Example 1 is a method for manufacturing a semiconductor device, comprising: providing a substrate; depositing a bottom layer over the substrate, the bottom layer comprising: a polymer main chain; a polarity switchable group comprising: an acid-labile group bonded to a first end group of the polymer main chain, a second end group comprising fluorine, and a cross-linkable group bonded to the polymer main chain; and a photoacid generator; depositing a photoresist layer over the bottom layer; exposing a portion of the photoresist layer and a portion of the bottom layer to a radiation source according to a pattern, thereby decomposing the photoacid generator in the exposed portion of the bottom layer to produce an acidic portion; baking the photoresist layer and the bottom layer so that the acidic portion reacts with the acid-labile group to separate the second end group from the polymer main chain; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer.

[0081] Example 2 is the method of Example 1, wherein depositing the photoresist layer includes depositing the photoresist layer directly on the bottom layer.

[0082] Example 3 is the method of Example 2, further comprising: before depositing the photoresist layer, baking the deposited bottom layer to activate the crosslinkable groups to bond to another polymer backbone.

[0083] Example 4 is the method of Example 2, further comprising: before depositing the photoresist layer, exposing the deposited bottom layer to an ultraviolet (UV) source to activate the crosslinkable groups to bond to another polymer backbone.

[0084] Example 5 is the method of Example 1, wherein the radiation source comprises an ArF excimer laser, a KrF excimer laser, or an extreme ultraviolet (EUV) radiation source.

[0085] Example 6 is the method of Example 1, wherein the photoresist layer is an organic metal photoresist comprising a metal selected from the group consisting of tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium.

[0086] Example 7 is the method described in Example 1, wherein the bottom layer also includes a photoresist affinity group bonded to the polymer main chain, wherein the photoresist affinity group includes between 1 and 30 carbon atoms, and wherein the affinity between the photoresist layer and the photoresist affinity group is greater than the affinity between the photoresist layer and the second end group of the polarity switchable group.

[0087] Example 8 is a method for manufacturing a semiconductor device, comprising: providing a substrate; depositing a bottom layer over the substrate, wherein the bottom layer comprises: a polymer backbone; a fluorine-containing group bonded to the polymer backbone; a polar group bonded to the polymer backbone; a thermally cross-linkable group bonded to the polymer backbone; a cross-linker; and a thermal acid generator comprising an acidic portion configured to catalyze the bonding between the polar group and the cross-linker; depositing a photoresist layer over the bottom layer; exposing a portion of the photoresist layer to a radiation source according to a pattern; baking the photoresist layer; and developing the exposed portion of the photoresist layer to transfer the pattern to the photoresist layer.

[0088] Example 9 is the method of Example 8, wherein depositing the photoresist layer includes depositing the photoresist layer directly on the bottom layer.

[0089] Example 10 is the method of Example 8, further comprising: before depositing the photoresist layer, baking the deposited bottom layer to activate the thermal acid generator to release the acidic portion for bonding the polar group and the cross-linking agent.

[0090] Example 11 is the method of Example 8, wherein the radiation source comprises an ArF excimer laser, a KrF excimer laser, or an extreme ultraviolet (EUV) radiation source.

[0091] Example 12 is the method of Example 8, wherein the photoresist layer is an organic metal photoresist comprising a metal selected from the group consisting of tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium.

[0092] Example 13 is the method described in Example 8, wherein the bottom layer also includes a photoresist affinity group bonded to the polymer backbone, wherein the photoresist affinity group includes between 1 and 30 carbon atoms, and wherein the affinity between the photoresist layer and the photoresist affinity group is greater than the affinity between the photoresist layer and the fluorine-containing group.

[0093] Example 14 is a method for manufacturing a semiconductor device, comprising: providing a substrate; depositing a bottom layer over the substrate, wherein the bottom layer comprises: a polymer backbone; an acid-labile group bonded to the polymer backbone; an ultraviolet (UV) curable group bonded to the acid-labile group; a thermal acid generator configured to release an acidic portion at a first temperature; and a photobase generator configured to release an alkaline portion when exposed to a radiation source; depositing a photoresist layer over the bottom layer; baking the photoresist layer at a second temperature lower than the first temperature; exposing a portion of the photoresist layer and a portion of the bottom layer to a radiation source according to a pattern, thereby releasing the alkaline portion from the photobase generator; baking the bottom layer at the first temperature, thereby releasing the acidic portion to neutralize the alkaline portion; and developing the exposed portion of the photoresist layer and the exposed portion of the bottom layer to transfer the pattern to the photoresist layer and the bottom layer.

[0094] Example 15 is the method of Example 14, wherein depositing the photoresist layer comprises depositing the photoresist layer directly on the bottom layer.

[0095] Example 16 is the method of Example 14, wherein the photoresist layer is an organic metal photoresist comprising a metal selected from the group consisting of tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium.

[0096] Example 17 is the method of Example 14, further comprising: before depositing the photoresist layer, exposing the deposited bottom layer to an ultraviolet (UV) source to activate the UV curable group to bond to another polymer backbone.

[0097] Example 18 is the method of Example 14, wherein the first temperature is between about 160°C and about 250°C.

[0098] Example 19 is the method of Example 14, wherein the second temperature is between about 60°C and about 150°C.

[0099] Example 20 is the method of Example 14, wherein the radiation source comprises an ArF excimer laser, a KrF excimer laser, or an extreme ultraviolet (EUV) radiation source.

Claims

1. A method for manufacturing a semiconductor device, comprising: providing a substrate; A bottom anti-reflection layer is deposited over the substrate, the bottom anti-reflection layer comprising: polymer backbone; a polarity switchable group comprising: a first end group directly bonded to the polymer backbone, a second end group comprising fluorine, and an acid labile group bonded between the first end group and the second end group; a photoresist-affinity group directly bonded to the polymer backbone; A cross-linkable group directly bonded to the polymer backbone; and Photoacid generators; depositing a photoresist layer over the bottom anti-reflective layer; exposing a portion of the photoresist layer and a portion of the bottom anti-reflective layer to an extreme ultraviolet (EUV) radiation source according to a pattern, thereby decomposing the photoacid generator in the exposed portion of the bottom anti-reflective layer to generate an acidic portion; baking the photoresist layer and the bottom anti-reflective layer so that the acidic moiety reacts with the acid-labile group to separate the second end group from the polymer backbone; and developing the exposed portions of the photoresist layer to transfer the pattern to the photoresist layer, Wherein, the acid-labile group comprises a carboxyl bond, Wherein, the photoresist affinity groups include -I, -Br, -Cl, -NH2, -SH, -N3, -S(=O)-, imine, aldehyde, amide, and sulfone.

2. The method according to claim 1, wherein: Depositing the photoresist layer includes depositing the photoresist layer directly on the bottom anti-reflective layer.

3. The method according to claim 2, further comprising: Prior to depositing the photoresist layer, the deposited bottom anti-reflective layer is baked to activate the cross-linkable groups to bond to another polymer backbone.

4. The method according to claim 2, further comprising: Prior to depositing the photoresist layer, the deposited bottom anti-reflective layer is exposed to an ultraviolet UV source to activate the cross-linkable groups to bond to another polymer backbone.

5. The method according to claim 1, wherein: The photoresist layer is an organometallic photoresist including a metal selected from the group consisting of tin, palladium, zirconium, cobalt, nickel, chromium, iron, rhodium and ruthenium.

6. The method according to claim 1, in, The photoresist-affinity group comprises between 1 and 30 carbon atoms, The affinity between the photoresist layer and the photoresist affinity group is greater than the affinity between the photoresist layer and the second end group of the polarity switchable group.

7. The method according to claim 1, wherein: The composition of the bottom anti-reflective layer is different from the composition of the photoresist layer.

8. A method for manufacturing a semiconductor device, comprising: providing a substrate; Depositing a bottom anti-reflection layer over the substrate, wherein the bottom anti-reflection layer comprises: polymer backbone; a polarity switchable group directly bonded to the polymer backbone; A cross-linkable group directly bonded to the polymer backbone; a photoresist-affinity group directly bonded to the polymer backbone; and Photoacid generators; curing the bottom anti-reflective layer; depositing a photoresist layer over the bottom anti-reflective layer after curing the bottom anti-reflective layer; curing the photoresist layer; exposing a portion of the photoresist layer and a portion of the bottom anti-reflective layer to an extreme ultraviolet (EUV) radiation source according to a pattern; After the exposing, baking the photoresist layer and the bottom anti-reflective layer; and developing the exposed portions of the photoresist layer to transfer the pattern to the photoresist layer, wherein the polarity switchable group comprises an acid-labile group, and the acid-labile group comprises a carboxyl bond, Wherein, the photoresist affinity groups include -I, -Br, -Cl, -NH2, -SH, -N3, -S(=O)-, imine, aldehyde, amide, and sulfone, Wherein, the polarity switchable group further comprises: A first end group bonded to the polymer backbone; and The second terminal group includes fluorine, Wherein, the acid-labile group is bonded between the first end group and the second end group.

9. The method according to claim 8, wherein: Curing the photoresist layer includes baking the photoresist layer.

10. The method according to claim 8, in, The photoresist-affinity group comprises between 1 and 30 carbon atoms, The affinity between the photoresist layer and the photoresist affinity group is greater than the affinity between the photoresist layer and the second end group of the polarity switchable group.

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