Hydrophobic cross-linkable pinning bottom layers with improved dry etch ability for patterned directed self-assembly of PS-B-PMMA type block copolymers

Abstract

The present invention relates to a new random copolymer whose repeat units include repeat units of structures (I), (II), and (III), wherein R1 and R2 are independently C-1 to C-4 alkyl groups, x and y are independently the number of R1 and R2, which are independently integers from 0 to 3, R3 is a C-1 to C-4 alkyl group, and R4 is selected from a C-2 to C-10 primary alkyl group, or a moiety comprising an aromatic hydrocarbon selected from the group consisting of a substituted or unsubstituted biphenyl moiety, a substituted or unsubstituted phenyl moiety, and a substituted or unsubstituted benzyl moiety. Another aspect of the invention is a composition comprising the random copolymer and an organic spin coating solvent. Another aspect of the invention is a coating using the composition to form a patterned pinning MAT for directed self-assembly.

Description

Invention Field

[0001] This invention relates to novel styrene-based polymers, novel compositions, and novel methods for aligning microdomains of oriented self-assembled block copolymers (BCPs) using these novel compositions. The compositions and methods can be used to manufacture electronic devices.

[0002] background

[0003] Directed self-assembly (DSA) of block copolymers is a method for generating increasingly smaller patterned features for fabricating microelectronic devices, where the critical size (CD) of nanoscale features can be achieved. Directed self-assembly methods are desired for extending the resolution capabilities of microlithography. In conventional lithography, ultraviolet (UV) radiation is used to expose a photoresist layer coated on a substrate or layered substrate through a mask. Positive or negative photoresists are useful, and they can also contain refractory elements, such as silicon, to enable dry development using conventional integrated circuit (IC) plasma processing. In positive photoresists, UV radiation through the mask induces a photochemical reaction in the photoresist, allowing the exposed areas to be removed with a developer solution or via conventional IC plasma processing. Conversely, in negative photoresists, UV radiation through the mask causes the exposed areas to become difficult to remove with a developer solution or conventional IC plasma processing. The integrated circuit features (e.g., gates, vias, or interconnects) are then etched into the substrate or layered substrate, and the remaining photoresist is removed. When using conventional photolithography processes, the feature size of integrated circuit features is limited. Further reductions in pattern size using radiation exposure are difficult due to limitations related to aberrations, focusing, proximity effects, minimum achievable exposure wavelength, and maximum achievable numerical aperture. The demand for large-scale integration has led to continuous shrinkage of circuit size and features in devices. Historically, the final resolution of features has depended on the wavelength of light used to expose the photoresist, which has its own limitations. Directional assembly techniques, such as patterned epitaxy and chemical epitaxy using block copolymer imaging, are ideal for enhancing resolution while reducing CD variation. These techniques can be used to enhance conventional UV lithography or achieve even higher resolution and CD control in methods employing EUV, electron beam, deep UV, or immersion lithography. Directional self-assembled block copolymers, containing etch-resistant copolymer blocks and highly etchable block copolymer blocks, produce very high-density patterned regions when coated, aligned, and etched on a substrate. In patterned epitaxial oriented self-assembly methods, block copolymers self-organize around a pre-patterned substrate using conventional photolithography (e.g., ultraviolet, deep UV, electron beam, extreme UV (EUV) exposure sources) to form repeating morphological features such as line / space (L / S) or contact hole (CH) patterns. In examples of L / S oriented self-assembly arrays, block copolymers can form self-aligned layered regions that can form parallel line-space patterns with varying pitches in trenches between pre-patterned lines, thereby enhancing pattern resolution by subdividing the space in the trenches between morphological lines into finer patterns. For example, diblock copolymers capable of microphase separation and containing plasma-etchable carbon-rich blocks (e.g., styrene or blocks containing other elements such as Si, Ge, Ti) and highly plasma-etchable or removable blocks can provide high-resolution pattern definition.Examples of highly etchable blocks may contain oxygen-rich monomers that are free of refractory elements and capable of forming highly etchable blocks, such as methyl methacrylate. The plasma etching gas used in etching processes that define self-assembly patterns is typically the same gas used in processes for manufacturing integrated circuits (ICs). In this way, finer patterns can be created on typical IC substrates than those definable by conventional photolithography, resulting in pattern multiplication. Similarly, features such as contact holes can be made denser by using patterned epitaxy, where suitable block copolymers align themselves by directional self-assembly around contact holes or pillar arrays defined by conventional photolithography, forming a denser array of etchable and etch-resistant regions, which in turn produces a denser array of contact holes during etching. Therefore, patterned epitaxy has the potential to provide pattern correction and pattern multiplication.

[0004] In chemical epitaxy, or pinned chemical epitaxy (also known as chemical epitaxy), the self-assembly of block copolymers forms around a surface with regions of different chemical affinities but no or only very slight morphology to guide the self-assembly process. For example, a substrate surface can be patterned using conventional lithography (e.g., UV, deep UV, electron beam EUV) to create surfaces with different chemical affinities in both line and space (L / S) patterns, where exposed areas whose surface chemistry has been altered by radiation alternate with unexposed areas that do not show chemical changes. These regions do not exhibit morphological differences, but do have surface chemical differences or pinning to orient the self-assembly of block copolymer fragments. Specifically, the oriented self-assembly of block copolymers containing etch-resistant (e.g., styrene repeating units) and fast-etch repeating units (e.g., methyl methacrylate repeating units) will allow for the precise placement of etch-resistant and highly etchable block copolymer fragments on the pattern. This technique allows for the precise placement of these block copolymers and subsequent pattern transfer onto the substrate after plasma or wet etching processes. The advantage of chemical epitaxy is that it allows for fine-tuning through variations in chemical differences, which helps improve line edge roughness and CD control, thereby enabling pattern correction. Other types of patterns, such as repeating contact hole (CH) arrays, can also be patterned using chemical epitaxy.

[0005] A neutral layer is a layer on or on the surface of a substrate that has no affinity for any of the block fragments of the block copolymer used in oriented self-assembly. Neutral layers are useful in patterning epitaxy methods for oriented self-assembly of block copolymers because they allow for the correct placement or orientation of the block polymer fragments used for oriented self-assembly, resulting in the correct placement of both etch-resistant and highly etchable block polymer fragments relative to the substrate. For example, in a surface containing lines and spatial features defined by conventional radiation lithography, a neutral layer allows the block fragments to be oriented such that they are perpendicular to the substrate surface. This orientation is ideal for both pattern correction and pattern multiplication, depending on the length of the block fragments in the block copolymer, which is related to the length between lines defined by conventional lithography. If the substrate interacts too strongly with one of the block fragments, it will cause it to lie flat on the surface to maximize the contact surface between the fragment and the substrate; such a surface will disrupt the vertical alignment required to achieve pattern correction or pattern multiplication based on features created by conventional lithography. Selected small regions or pinned substrates are modified to strongly interact with one block of the block copolymer, leaving the remaining portion of the surface coated with a pinned MAT layer. This can be used to force the domains of the block copolymer to align in the desired direction, which is the basis for pinned chemical epitaxy or patterned epitaxy used for pattern multiplication. The MAT layer is cross-linked and insoluble in any layer coated on it, and can be used as a neutral layer or pinning layer in DSA.

[0006] Compositions containing standard cross-linked polystyrene pinned MAT layer materials exhibit high plasma etching resistance due to their high aromatic hydrocarbon content and the fact that they do not allow for simple patterning using dry etching processes, which would affect the development of pre-patterns suitable for directional self-assembly. Specifically, a problem associated with dry etching of standard cross-linked polystyrene pinned MAT DSA underlayers for pattern multiplication of pre-patterns that can be formed via dry 193nm or 193nm immersion lithography or extreme ultraviolet (EUV) lithography is that the high etch resistance of these standard MAT materials used for pattern multiplication or correction can impair the favorable morphological design of the pre-pattern by generating DSA defects that lead to edge misalignment, such as bridging, dislocations, and inhomogeneities in the critical size of block copolymer domains. Problems associated with dry etching of cross-linkable polystyrene underlayers in 193i lithography processes (193nm immersion lithography) can impair the favorable morphological design of the pre-pattern and generate DSA defects, such as those in bridging, substrates, and standard polystyrene pinned MAT layer compositions containing an underlayer anti-reflective coating. Invention Overview

[0008] To facilitate the processing of hydrophobic crosslinkable mat substrates used for DSA pre-patterning development for chemical epitaxial directional self-assembly processes, a series of novel polystyrene copolymers containing small amounts of polar copolymers were synthesized. Specifically, several terpolymers containing repeating units derived from styrene and 4-vinylbenzocyclobutene, as well as repeating units of methacrylates derived from polar alkyl or aromatic methacrylate moieties, were developed. The dry etching characteristics of these novel terpolymers were tuned based on the presence and concentration of these polar alkyl or aromatic methacrylate-containing moieties. These novel hydrophobic crosslinkable mat substrates exhibited controllable pre-patterning morphologies and positively impacted the assembly of PS-b-PMMA block copolymers for line multiplication DSA processes due to the more uniform domain sizes of the PS and PMMA blocks.

[0009] One aspect of the invention is a random copolymer whose repeating units comprise repeating units of structures (I), (II), and (III), wherein R1 and R2 are independently C-1 to C-4 alkyl groups, x and y are independently the number of R1 and R2, and are independently integers from 0 to 3, R3 is a C-1 to C-4 alkyl group, and R4 is selected from C-2 to C-10 primary alkyl groups, or comprises an aromatic moiety selected from the group consisting of a substituted or unsubstituted biphenyl moiety, a substituted or unsubstituted phenyl moiety, and a substituted or unsubstituted benzyl moiety, and m, n, and o are the number of repeating units of structures (I), (II), and (III), respectively, wherein the molar percentage of the repeating units of structure (I) ranges from about 60 mol% to The molar percentage of repeating units of structure (II) ranges from about 5 mol% to about 25 mol%, and the molar percentage of repeating units of structure (III) ranges from about 2 mol% to about 18 mol%, wherein if other different repeating units are present, the sum of the molar percentages of these repeating units is less than 100 mol%, or if only repeating units of structures (I), (II) and (III) are present, it is equal to 100 mol%, and furthermore, the polydispersity of said random copolymer is from about 1.25 to about 1.80, and Mw is from about 30,000 to about 45,000 Daltons, and said random copolymer does not have reactive end groups containing a portion of benzyl alcohol.

[0010]

[0011] Another aspect of the present invention is a composition comprising the random copolymer and an organic spin-coating solvent.

[0012] Another aspect of the invention is to use a coating of the composition to form patterned studded MATs for directional self-assembly. Figure 1 This demonstrates one possible chemical epitaxial approach that can be employed when using a crosslinked pinned MAT layer formed from a composition comprising the novel random copolymer described above.

[0013] Brief description of the attached figures

[0014] Figure 1 Examples of suitable chemical epitaxial directional self-assembly schemes for crosslinked pinned MAT layers formed by novel random copolymers comprising repeating units (I), (II) and (III) of repeating units.

[0015] Figure 2 Reference Comparative Example 1 shows that it is not neutral to PS-b-PMMA, and the new material series Examples 1, 2, and 3 (1 to 3 with different concentrations of n-butyl methacrylate monomer) show similar behavior. Conditions: Coating Examples 1 to 3 and Comparative Example 1, baking at 250°C / 30 min / N2, coating with neutral brush 1, baking at 250°C / 30 min / N2, 2 min EBR rinse, dry baking, coating with block copolymer 1, at 35 nm ctg 50, annealing at 250°C / 30 min / N2.

[0016] Figure 3 Comparison of etch rate and normalized etch rate. Overall etching improvement in Examples 1, 2, and 3 compared to Comparative Example 1. Conditions: ACT12: 110°C / 1 min, 250°C / 30 min (N2). Trion etching machine: Pressure = 70 mT; Top / Bottom (W) = 50 / 50; O2 (sccm) = 50.

[0017] Figure 4 Comparison of etch rate and normalized etch rate. Overall etching improvement in Examples 1, 2, 11, and 12 compared to Comparative Example 1. Conditions: ACT12: 110°C / 1 min, 250°C / 30 min (N2). Trion etching machine: Pressure = 70 mT; Top / Bottom (W) = 50 / 50; O2 (sccm) = 50.

[0018] Figure 5 Photolithography performance at P90nm. Compared to the pinned MAT layers from Examples 1 and 2 or Comparative Example 1, Example 3 induces a larger post-development inspection (ADI) CD.

[0019] Figure 6 Photolithography performance at 90 nm. Compared to Examples 1 and 2 or Comparative Example 1, Example 3 induces a larger post-etch inspection (AEI) CD.

[0020] Figure 7 Polymer as a pinned-guided DSA process window; Comparison of Comparative Example 1 with Examples 1, 2, and 3.

[0021] Figure 8The average CD and 3σ of the DSA lines formed using Comparative Example 1 and Examples 1, 2 and 3 are used.

[0022] Figure 9 : Instances of booted and unbooted DSA lines formed and used for CD evaluation.

[0023] Detailed Explanation

[0024] It should be understood that the foregoing general description and the following detailed description are illustrative and explanatory, and do not limit the subject matter claimed. In this application, unless otherwise expressly stated, the use of the singular includes the plural, the words “a” or “an” mean “at least one,” and the use of “or” means “and / or.” Furthermore, the use of the term “comprising” and other forms such as “including” and “included” is not restrictive. Additionally, unless otherwise expressly stated, the terms “element” or “component” cover elements and components comprising one unit as well as elements or components comprising more than one unit. As used herein, the conjunction “and” is intended to include, and the conjunction “or” is not intended to be exclusive unless otherwise stated. For example, the phrase “or, alternatively” is intended to be exclusive. As used herein, the term “and / or” refers to any combination of the foregoing elements, including the use of a single element.

[0025] The chapter headings used herein are for organizational purposes and should not be construed as limiting the subject matter described. All references or portions thereof cited in this application, including but not limited to patents, patent applications, articles, books, and papers, are hereby expressly incorporated herein by reference in their entirety for any purpose. If one or more incorporated references and similar materials define a term in a manner that contradicts the definition used in this application, the definition used in this application shall prevail.

[0026] In this article, "alkyl" refers to a hydrocarbon group that can be straight-chain, branched (e.g., methyl, ethyl, propyl, isopropyl, tert-butyl, etc.), or cyclic (e.g., cyclohexyl, cyclopropyl, cyclopentyl, etc.).

[0027] "Alkoxy" refers to an alkyl group as defined above (e.g., methoxy, ethoxy, propoxy, butoxy, 1,2-isopropoxy, cyclopentoxy, cyclohexyloxy, etc.) connected by an oxygen (-O-) moiety.

[0028] "Fluoroalkyl" refers to a straight-chain, cyclic, or branched saturated alkyl group as defined above, wherein hydrogen has been partially or completely replaced by fluorine (e.g., trifluoromethyl, perfluoroethyl, 2,2,2-trifluoroethyl, perfluoroisopropyl, perfluorocyclohexyl, etc.).

[0029] "Fluoroalkoxy" refers to a fluoroalkyl group as defined above (e.g., trifluoromethoxy, perfluoroethoxy, 2,2,2-trifluoroethoxy, perfluorocyclohexyloxy, etc.) connected by an oxygen (-O-) moiety.

[0030] In this document, when referring to alkyl, alkoxy, fluoroalkyl, or fluoroalkoxy moieties having a possible range of carbon atoms beginning with C-1, e.g., "C-1 to C-10 alkyl" or "C-1 to C-10 fluoroalkyl" are used as non-limiting examples, the range covers primary alkyl, straight-chain alkyl (also known as n-alkyl), secondary alkyl, alkoxy, fluoroalkyl, and fluoroalkoxy moieties beginning with C-1, but only branched alkyl, branched alkoxy, cycloalkyl, cycloalkoxy, branched fluoroalkyl, and cyclofluoroalkyl moieties beginning with C-3 are specified.

[0031] The term "primary alkyl" refers to a portion of the substituent whose linking site is a primary carbon atom, wherein the remainder of the substituent, excluding the linking site, can be H (also called methyl), a straight-chain alkyl portion (e.g., n-alkyl), a branched alkyl, or a cycloalkyl. Specific, non-limiting examples are methyl, ethyl, n-propyl, isopropyl, isobutyl, n-butyl, n-pentyl, 2-methylpentyl, 3-methylpentyl, n-hexyl, 2-methylhexyl, n-heptyl, 2-methylheptane, 3-methylheptane, n-octyl, (cyclohexyl)methyl, (CH2-cyclohexyl), and (cyclopentyl)methyl(CH2-cyclopentyl). A further description of C-1 to C-10 primary alkyl groups is that these primary alkyl groups have a total of C-1 to C-10 carbon atoms.

[0032] In this document, the term "alkylene" refers to a hydrocarbon group having two connecting points, which may be straight-chain, branched, or cyclic (e.g., methylene, ethylene, 1,2-isopropylene, 1,4-cyclohexylene, etc.). Again, when a possible carbon range (e.g., C-1 to C-20) is specified as a non-limiting example, the range covers straight-chain alkylenes beginning at C-1 (also called methyl), but only branched alkylenes or branched cycloalkylenes beginning at C-3 are specified. The term alkylene also covers unsubstituted alkylenes (also known as straight-chain, branched, or cyclic alkylenes containing only hydrogen) and substituted alkylenes (also known as straight-chain, branched, or cyclic alkylenes containing these substituents other than hydrogen), wherein these substituted alkylenes are alkylenes in which one or more hydrogens are replaced by substituents selected from aryl, halogen, C-1 to C-20 alkyl, or C-1 to C-20 alkoxy groups.

[0033] In this document, the term "contains an aromatic moiety" refers to an aromatic monofunctional group containing a benzyl moiety selected from substituted or unsubstituted, biphenyl moiety selected from substituted or unsubstituted, and substituted or unsubstituted, phenyl moiety selected from substituted or unsubstituted. In this document, unsubstituted means the presence of only hydrogen, while the term substituted means the presence of at least one substituent selected from halogen, C-1 to C-20 alkyl, fluoroalkyl, perfluoroalkyl, and C-1 to C-20 alkoxy, or a mixture of these substituents.

[0034] In this document, the term "aryl" refers to an aromatic moiety having a single linking point, which may be a single benzene moiety (e.g., phenyl), a polycyclic aromatic moiety having a single linking point, such as that derived from naphthalene, anthracene, pyrene, etc., or multiple benzene rings in a chain having a single linking point (e.g., 1,4-biphenyl). The term "aryl" also encompasses the above-mentioned moiety as an unsubstituted aryl (also referred to as hydrogen as a substituent only) or a substituted aryl, wherein the substituent is selected from halogens, C-1 to C-20 alkyl groups, or C-1 to C-20 alkoxy groups.

[0035] “Lo” is the bulk repeating period of the block copolymer, as defined in Erik W. Edwards et al., Macromolecules 2007, 40, pp. 90-96.

[0036] If two connect parts are adjacent to each other and both are designated as single-price keys, then the designation represents a single connect part of a single-price key (e.g., if both connect parts L1 and L2 are designated as single-price keys, this represents a single connect part of a single-price key).

[0037] One aspect of the invention is a random copolymer whose repeating units comprise repeating units of structures (I), (II), and (III), wherein R1 and R2 are independently C-1 to C-4 alkyl groups, x and y are independently the number of R1 and R2, and are independently integers from 0 to 3, R3 is a C-1 to C-4 alkyl group, and R4 is selected from C-2 to C-10 primary alkyl groups, or comprises an aromatic moiety selected from the group consisting of a substituted or unsubstituted biphenyl moiety, a substituted or unsubstituted phenyl moiety, and a substituted or unsubstituted benzyl moiety, and m, n, and o are the number of repeating units of structures (I), (II), and (III), respectively, wherein the molar percentage of the repeating units of structure (I) ranges from about 60 mol% to The random copolymer comprises approximately 95 mol%, the repeating units of structure (II) range from approximately 5 mol% to approximately 25 mol%, and the repeating units of structure (III) range from approximately 2 mol% to approximately 18 mol%, wherein if other different repeating units are present, the sum of the mol% of these repeating units is less than 100 mol%, or if only repeating units of structures (I), (II), and (III) are present, it is equal to 100 mol%, and furthermore, the polydispersity of the random copolymer is approximately 1.25 to approximately 1.80, and the Mw is approximately 30,000 to approximately 45,000 Daltons, and the random copolymer does not have reactive end groups containing a portion of benzyl alcohol. In another aspect of this embodiment, the random copolymer is substantially composed of repeating units of structures (I), (II), and (III). In yet another aspect of this embodiment, the random copolymer is composed of repeating units of structures (I), (II), and (III), wherein the sum of the mol% of repeating units (I), (II), and (III) is equal to 100 mol%.

[0038]

[0039] In another aspect of the random copolymer, the repeating units of structure (III) range from about 2.5 mol% to about 20 mol%. In another aspect of this embodiment, the repeating units range from about 2.5 mol% to about 16 mol%. In yet another aspect of this embodiment, the repeating units range from about 3 mol% to about 15 mol%.

[0040] In another aspect of the random copolymer, the repeating units of structure (II) range from about 6 mol% to about 23 mol%. In another aspect of this embodiment, the repeating units range from about 7 mol% to about 20 mol%. In yet another aspect of this embodiment, the repeating units range from about 7 mol% to about 15 mol%.

[0041] In another aspect of the random copolymer, the repeating units of structure (I) range from about 62 mol% to about 93 mol%. In another aspect of this embodiment, the repeating units range from about 60 mol% to about 90 mol%.

[0042] In another aspect of the random copolymer, the repeating units of structure (I) range from about 60 mol% to about 90 mol%, the repeating units of structure (II) range from about 7 mol% to about 20 mol%, and the repeating units of structure (III) range from about 3 mol% to about 15 mol%.

[0043] In another aspect of the random copolymer, y is 0.

[0044] In the other aspect of the random copolymer, x is 0.

[0045] In another aspect of the random copolymer, x and y are 0.

[0046] In another aspect of the random copolymer, R3 is CH3.

[0047] In another aspect of the random copolymer, R4 is a C-2 to C-10 primary alkyl group. In another aspect of this embodiment, R4 is a C-2 to C-9 primary alkyl group. In another aspect of this embodiment, R4 is a C-2 to C-8 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-2 to C-7 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-3 to C-7 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-3 to C-6 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-4 to C-6 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-4 to C-5 primary alkyl group. In another aspect of this embodiment, R4 is n-butyl.

[0048] In another aspect of the random copolymer, R4 is a C-2 to C-6 primary alkyl group. In another aspect of this embodiment, R4 is a C-2 to C-5 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-2 to C-4 primary alkyl group. In yet another aspect of this embodiment, R4 is a C-2 to C-3 primary alkyl group. In yet another aspect, R4 is n-propyl. In yet another aspect of this embodiment, R4 is ethyl.

[0049] In another aspect of the random copolymer, R4 is an aromatic moiety. In one embodiment, R4 is a benzyl moiety. In another embodiment, R4 is benzyl.

[0050] In another aspect of the random copolymer, R4 is an aromatic moiety. In one embodiment, R4 is a phenyl moiety. In another embodiment, it is a substituted phenyl group. In yet another embodiment, R4 is a phenyl group.

[0051] In another aspect of the random copolymer, R4 is the aromatic moiety. In one embodiment, R4 is a biphenyl. In another embodiment, it is a substituted biphenyl moiety. In another case, it is an unsubstituted biphenyl. In yet another embodiment, R4 is [1,1'-biphenyl-4-yl].

[0052] In another aspect of the random copolymer, the repeating unit has the following structures (Ia), (IIa), and (IIIa):

[0053]

[0054] In another aspect of this embodiment, the repeating units of structure (Ia) are present at about 60 mol% to about 90 mol%, the repeating units of structure (IIa) are present at about 5 mol% to about 25 mol%, and the repeating units of structure (IIIa) are present at about 2 mol% to about 18 mol%.

[0055] In another aspect of this embodiment, the repeating unit of structure (Ia) is present at about 75 mol% to about 90 mol%, the repeating unit of structure (IIa) is present at about 5 mol% to about 15 mol%, and the repeating unit of structure (IIIa) is present at about 2 mol% to about 18 mol%.

[0056] In another aspect of the random copolymer described herein, the repeating unit has the following structures (Ia), (IIa), and (IIIa-1):

[0057]

[0058] In another aspect of this embodiment, the repeating units of structure (Ia) are present at about 60 mol% to about 90 mol%, the repeating units of structure (IIa) are present at about 5 mol% to about 25 mol%, and the repeating units of structure (IIIa-1) are present at about 2 mol% to about 18 mol%.

[0059] In another aspect of this embodiment, the repeating units of structure (Ia) are present at about 60 mol% to about 90 mol%, the repeating units of structure (IIa) are present at about 5 mol% to about 25 mol%, and the repeating units of structure (IIIa-1) are present at about 2 mol% to about 18 mol%.

[0060] In another aspect of the random copolymer, the repeating unit has the following structures: (Ia), (IIa), and (IIIb):

[0061]

[0062] In another aspect of this embodiment, the repeating unit of structure (Ia) is present at about 60 mol% to about 90 mol%, the repeating unit of structure (IIa) is present at about 5 mol% to about 25 mol%, and the repeating unit of structure (IIIb) is present at about 2 mol% to about 18 mol%.

[0063] In another aspect of this embodiment, the repeating unit of structure (Ia) is present in an amount of about 65 mol% to about 85 mol%, the repeating unit of structure (IIa) is present in an amount of about 5 mol% to about 15 mol%, and the repeating unit of structure (IIIb) is present in an amount of about 10 mol% to about 18 mol%.

[0064] In another aspect of the random copolymer, the repeating unit has the following structures: (Ia), (IIa), and (IIIc):

[0065]

[0066] In another aspect of this embodiment, the repeating unit of structure (Ia) is present at about 60 mol% to about 90 mol%, the repeating unit of structure (IIa) is present at about 5 mol% to about 25 mol%, and the repeating unit of structure (IIIc) is present at about 2 mol% to about 18 mol%.

[0067] In another aspect of this embodiment, the repeating unit of structure (Ia) is present at about 65 mol% to about 85 mol%, the repeating unit of structure (IIa) is present at about 5 mol% to about 15 mol%, and the repeating unit of structure (IIIc) is present at about 10 mol% to about 18 mol%.

[0068] In another aspect of the random copolymer described herein, the repeating unit has the following structures (Ia), (IIa), and (IIId):

[0069]

[0070] In another aspect of this embodiment, the repeating units of structure (Ia) are present at about 60 mol% to about 90 mol%, the repeating units of structure (IIa) are present at about 5 mol% to about 25 mol%, and the repeating units of structure (IIId) are present at about 2 mol% to about 18 mol%.

[0071] In another aspect of this embodiment, the repeating unit of structure (Ia) is present at about 65 mol% to about 80 mol%, the repeating unit of structure (IIa) is present at about 5 mol% to about 15 mol%, and the repeating unit of structure (IIId) is present at about 10 mol% to about 18 mol%.

[0072] Another aspect of the present invention is a novel composition comprising the random copolymer and an organic spin-coating solvent.

[0073] On the other hand, the novel composition includes other additives as components, such as surfactants, leveling agents, stabilizers, etc. In one aspect of this embodiment, a surfactant is included as an additive to promote coating.

[0074] In another aspect of the novel composition, the organic spin-coating solvent is a solvent capable of dissolving the random copolymer and any other optional components as described above. The organic spin-coating solvent can be a single solvent or a mixture of solvents. Suitable solvents are organic solvents that may include, for example, glycol ether derivatives such as ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether (PGME), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol dimethyl ether, propylene glycol n-propyl ether, or diethylene glycol dimethyl ether; glycol ether ester derivatives such as ethyl cellosolve acetate, methyl cellosolve acetate, or propylene glycol monomethyl ether acetate (PGMEA); carboxylic acid esters such as ethyl acetate, n-butyl acetate, and amyl acetate; carboxylic acid esters of diacids such as diethoxylate and diethyl malonate; dicarboxylic acid esters of glycols such as ethylene glycol diacetate and propylene glycol diacetate; and hydroxycarboxylic acid esters such as methyl lactate. Ethyl lactate (EL), ethyl glycolate, and ethyl 3-hydroxypropionate; ketone esters, such as methyl pyruvate or ethyl pyruvate; alkoxycarboxylic acid esters, such as methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 2-hydroxy-2-methylpropionate, or methyl ethoxypropionate; ketone derivatives, such as methyl ethyl ketone, acetylacetone, cyclopentanone, cyclohexanone, or 2-heptanone; ketone ether derivatives, such as diacetone alcohol methyl ether; ketone alcohol derivatives, such as acetone alcohol or diacetone alcohol; ketals or acetals, such as 1,3-dioxane and diethoxypropane; lactones, such as butyrolactone; amide derivatives, such as dimethylacetamide or dimethylformamide, anisole, and mixtures thereof.

[0075] In another aspect of the novel composition, the random copolymer comprises about 0.1% to about 2% by weight of the total weight of the composition including the organic spin-coating solvent. In another aspect, it comprises about 0.1% to about 1% by weight. In yet another embodiment, it comprises about 0.2% to about 0.5% by weight. In yet another embodiment, it comprises about 0.2% to about 0.3% by weight.

[0076] Another aspect of the present invention is a method for forming a copolymer crosslinking layer on a substrate using the novel composition described herein, comprising the following steps:

[0077] a) Forming a coating of the novel composition described herein on a substrate;

[0078] b) Heat the coating at a temperature ranging from about 90°C to about 180°C to remove the solvent;

[0079] c) Heating the coating at a temperature ranging from about 200°C to about 350°C to form a crosslinked copolymer coating or a pinned MAT layer.

[0080] Another aspect of the invention, also employing the novel compositions described herein, is a chemical epitaxial method for forming images using the directional self-assembly of block copolymer layers, comprising the following steps:

[0081] a-1) A substrate is coated with a graftable neutral layer polymer precursor to form coating 1;

[0082] b-1) Heat coating 1 at a temperature of 90°C to 180°C to remove the solvent;

[0083] c-1) The coating 1 after step b-1) is heated at a temperature of about 200°C to about 350°C, preferably about 330°C, to affect the grafting;

[0084] d-1) Treat coating 1 after step c-1) with an organic solvent to remove the ungrafted neutral layer polymer, leaving an insoluble grafted neutral layer on the substrate.

[0085] e-1) Coating a negative photoresist layer onto the grafted neutral layer;

[0086] f-1) A negative pattern is formed in the photoresist layer, thereby forming a region in which the grafted neutral layer is covered or not covered by the photoresist, wherein the pattern in the photoresist includes repeating patterns of small nanoscale size and large regions that do not contain repeating patterns of nanoscale size after the photoresist is removed during imaging.

[0087] g-1) Etching to remove the neutral layer areas not covered in step f-1), leaving the substrate exposed in these areas;

[0088] h-1) After step g-1), the photoresist is peeled off from the substrate, leaving a patterned substrate, wherein the substrate areas not covered by the photoresist in step f-1) do not have a grafted neutral layer and the areas covered by the photoresist in step f-1) retain a grafted neutral layer.

[0089] i-1) Coating a patterned substrate with the novel composition described herein to form coating 2;

[0090] j-1) Heat coating 2 at a temperature of about 90°C to about 180°C to remove the solvent;

[0091] k-1) Heat coating 2 for about 1 to about 10 minutes at a temperature ranging from about 200°C to about 350°C to leave an insoluble crosslinked pinned MAT layer in the area of ​​the substrate without the grafted neutral layer, thereby creating a substrate with a pinned MAT layer area and a neutral layer area.

[0092] l-1) A block copolymer coating containing etch-resistant styrene blocks and highly etchable aliphatic blocks is applied to a substrate containing a patterned neutral layer and a stapled MAT layer to create a substrate containing both a patterned neutral layer and a patterned stapled MAT layer.

[0093] m-1) The block copolymer layer was annealed until directional self-assembly occurred in the small nanoscale repeating pattern of the substrate, but no vertical orientation of the block polymer domains occurred in the large region containing the pinned MAT layer.

[0094] o-1) Etching the block copolymer to remove highly etchable blocks of the copolymer and forming repeating nanoscale patterns in the region on the substrate where the block copolymer undergoes directional self-assembly in step m-1).

[0095] A chemical epitaxial method for forming images using the directional self-assembly of block copolymer layers with the novel compositions described herein includes the following steps:

[0096] a-2) Forming a crosslinkable or both crosslinkable and graftable neutral layer polymer precursor coating on a substrate;

[0097] b-2) Heating the crosslinkable neutral polymer layer precursor coating or the crosslinkable and graftable precursor coating at a temperature of 90°C to 180°C to remove the solvent.

[0098] c-2) Heating a crosslinkable neutral layer polymer precursor coating or a coating precursor coating that is both crosslinkable and graftable at a temperature of 200°C to 330°C to form a crosslinked neutral layer or a crosslinked and grafted neutral layer.

[0099] d-2) A coating of negative photoresist layer is provided on a cross-linked neutral layer or on a cross-linked and grafted neutral layer;

[0100] e-2) A negative pattern is formed in the photoresist layer, thereby forming a region in which the cross-linked or cross-linked and grafted neutral layer is covered or uncovered by the photoresist, wherein the pattern in the photoresist includes small nano-repeating patterns and large area regions that do not contain nano-sized repeating patterns after the photoresist is removed during imaging.

[0101] f-2) Use plasma etching to remove the neutral layer regions not covered in step e-2), remove crosslinked or crosslinked and grafted neutral layers, leaving bare substrate in the regions not covered in step e-2).

[0102] g-2) After step f-2), the photoresist is peeled off from the substrate, leaving a patterned substrate, wherein the substrate areas not covered by the photoresist in step e-2) do not contain a cross-linked or cross-linked and grafted neutral layer, and the areas covered by the photoresist in step f-2) retain a cross-linked or cross-linked and grafted neutral layer.

[0103] h-2) Coating a patterned substrate with the novel composition described herein to form coating 3;

[0104] i-2) Heat coating 3 at a temperature of about 90°C to about 180°C to remove the solvent;

[0105] j-2) The coating 3 is heated at a temperature of about 200°C to about 350°C for about 1 to about 10 minutes to form an insoluble crosslinked pinned MAT layer in the region of the substrate without the grafted neutral layer, thereby creating a substrate containing the pinned MAT layer region and the neutral layer region.

[0106] k-2) Apply a block copolymer coating containing etch-resistant styrene blocks and highly etchable aliphatic blocks to a substrate containing a patterned neutral layer and a pinned MAT layer;

[0107] l-2) Anneal the block copolymer layer until directional self-assembly occurs in the small nanoscale repeating pattern of the substrate, but in which vertical orientation of the block polymer domains does not occur in the large region containing the grafted pinned MAT layer.

[0108] m-2) Etching the block copolymer to remove highly etchable blocks of the copolymer and forming repeating nanoscale patterns in the region on the substrate where the block copolymer undergoes directional self-assembly in step l-2).

[0109] A chemical epitaxial method for forming images using the directional self-assembly of block copolymer layers with the novel compositions described herein includes the following steps:

[0110] a-3) Forming a coating of the novel composition described herein on a substrate to form a film.

[0111] b-3) The membrane is baked at a temperature of about 200°C to about 350°C for about 1 to about 10 minutes to form an insoluble cross-linked pinned MAT layer.

[0112] c-3) A coating that provides a positive or negative photoresist layer on the crosslinked pinned MAT layer.

[0113] d-3) Forming negative or positive images in negative or positive photoresist layers, respectively, thereby creating cross-linked pinning of areas covered or uncovered by the photoresist.

[0114] e-3) Use plasma etching to remove the cross-linked pinned MAT layer in the areas not covered in step d-3), leaving the bare substrate and the cross-linked pinned MAT layer in the areas covered in step d-3), forming a patterned cross-linked pinned MAT layer.

[0115] f-3) The patterned cross-linked pinned MAT layer is coated with a neutral layer coating.

[0116] g-3) Curing the neutral layer coating and washing away the uncured neutral layer formed in areas of the substrate not covered by the patterned crosslinked pinned MAT layer with solvent, thereby forming a neutral orientation layer on the substrate, thus forming a chemical epitaxial orientation layer.

[0117] h-3) A block copolymer solution is coated onto the chemically epitaxially oriented layer to form a block copolymer coating.

[0118] i-3) Anneal the block copolymer coating to form a oriented self-assembled film of the block copolymer on the chemical epitaxial orientation layer.

[0119] j-3) Etching the block copolymer to remove highly etchable blocks of the copolymer and forming repeating nanoscale patterns in the region on the substrate where the block copolymer undergoes directional self-assembly in step h-3).

[0120] In another aspect of the chemical epitaxial method described herein, including steps a-1) to o-1), a-2) to m-2), or a-3) to j-3), in the above-described pinned MAT layer baking process j-1), j-2), or b-3), the baking time may also vary from about 2 minutes to about 7 minutes in one embodiment, and from about 2 minutes to about 5 minutes in another embodiment.

[0121] In another aspect of the chemical epitaxy method, the thickness of the crosslinked pinned MAT layer in steps c), k-1), j-2), or b-3) is about 5 nm to about 20 nm. In another aspect, its thickness is about 7 nm to about 14 nm.

[0122] In another aspect of the chemical epitaxial method including steps a-1) to o-1), a-2) to m-2), or a-3) to j-3), the substrate is a suitable substrate described later herein. As an example, a semiconductor substrate, such as silicon, can be used. As another example, the substrate is metal. As a further example, the substrate can be a metal oxide. In yet another example, it can be SiN. In still another example, it can be an organic coating, such as a bottom anti-reflective coating (BARC).

[0123] In another aspect of the chemical epitaxial method including steps a-1) to o-1), a-2) to m-2), or a-3) to j-3), the block copolymer comprising etch-resistant styrene blocks and highly etchable aliphatic blocks is a block copolymer as described herein. In one aspect of this embodiment, it is a block copolymer of styrene and methyl methacrylate.

[0124] In another aspect of the chemical epitaxial method including steps a-1) to o-1), a-2) to m-2), or a-3) to i-3), in steps m-1), l-2), or i-3), the annealing of the block copolymer coating may be carried out at a temperature of about 230°C to about 260°C for about 5 minutes to about 30 minutes.

[0125] In another aspect of the chemical epitaxial method including steps a-1) to o-1), a-2) to m-2), or a-3) to j-3), self-assembled block copolymer domains are used to provide a selective barrier layer against etching into the substrate. This selectivity in etching can be imparted by the assembled block domains to different reactivity with the chemical etchant used to etch the substrate, or by different reactivity with the plasma etching step used to etch the substrate. One example is that one block is a plasma-resistant etch-resistant block, while another block is highly plasma-etchable. Selective etching into the substrate via self-assembled block copolymers can be used to provide an image in the substrate. In turn, this image can be used for the fabrication of microelectronic devices by defining the structure in a specific layer used in the process of manufacturing memory or logic devices.

[0126] In another aspect of the chemical epitaxial method including steps a-3) to j-3), the patterned cross-linked pinned MAT layer in step c-3) above, a negative or positive resist can be coated on the cross-linked pinned MAT layer, imaged and developed, and the resulting patterned resist is used as an etch stop layer to create the patterned cross-linked pinned MAT layer.

[0127] In another aspect of the chemical epitaxial method including steps a-1) to o-1), a-2) to m-2), or a-3) to j-3), the etching step can be performed, for example, by plasma or chemical etching. For positive resists, their tones are inverted by developing them using an organic solvent instead of a TMAH-based developer, thus obtaining a negative image instead of a positive image. Furthermore, the radiation used to form the resulting photoresist pattern can be selected from electron beam, broadband, 193nm immersion lithography, 13.5nm, 193nm, 248nm, 365nm, and 436nm radiation.

[0128] Another aspect of the invention is the use of the copolymer or composition described above for coating a substrate, preferably for coating a substrate in a chemical epitaxial process.

[0129] Typically, but not theoretically constrained, when one domain of the substrate and the diblock copolymer forming the sheet has a more favorable interfacial energy than the other, the interaction between the substrate and the favorable domain causes the sheet to be oriented parallel to the substrate in the film, rather than perpendicularly. This parallel morphology of the film exhibits three typical structures: asymmetric, symmetric, and island structures, depending on the BCP film thickness and the interfacial energy between the BCP domains and the surrounding environment (e.g., air or N2). On grafted polystyrene (PS) substrates coated with BCP and annealed in an N2 atmosphere, the PS and PMMA domains have the same interfacial energy. Therefore, both PS and PMMA domains can be oriented parallel to the substrate surface.

[0130] Specifically, in the large area of ​​the neutral layer stripped in the above method, a novel copolymer is crosslinked onto the exposed substrate. This crosslinked layer produces a surprisingly strong, dense, and uniform pinned MAT layer, which can be used to avoid the formation of defects in these large areas, which would occur in block copolymers forming diblock sheets of styrene (or other etch-resistant polymer blocks with similar polarity to the novel crosslinked layer formed by the novel copolymer described herein) and aliphatic blocks (or other etchable polymer blocks with different polarity than the styrene blocks). The formation of this unexpectedly strong pinned MAT layer produces a surface with a consistent parallel layered orientation that is highly favorable to the block copolymer, consistent over the entire large area with the crosslinked pinned MAT layer formed by the novel copolymer described herein. These parallel layered orientations produce a block copolymer coating that, along with its uniform orientation, provides a consistent etching rate over the entire area during patterning etching. This uniformity of large-area etching on the block copolymer coating prevents the formation of defective areas with inconsistent etching rates. This will occur if the block copolymer coating forms self-assembled islands or pore structures during self-assembly; otherwise, for a given Lo with a sheet forming a diblock copolymer that will form block copolymer domains with parallel layered orientation in well-pinned regions, this will occur at the substrate. Therefore, for a cross-linked pinned MAT layer formed from a novel styrene polymer, a surprisingly strong and uniform pinned MAT layer is formed, which in turn leads to the consistent formation of parallel layered structures over the entire large area without containing nanoscale repeating patterns, such as lines and spaces or trenches.

[0131] In the chemical epitaxial method using the novel compositions described above, the block copolymers used in conjunction with the novel compositions capable of forming pinned MAT layers can be any block copolymer capable of forming domains through self-assembly. The microdomains are formed from blocks of the same type that tend to self-associate. Typically, block copolymers used for this purpose are polymers in which repeating units derived from monomers are arranged in blocks of different composition, structure, or both, and are capable of phase separation and forming domains. These blocks have different properties that can be used to remove one block while leaving another block intact on the surface, thereby providing a pattern on the surface. Therefore, blocks can be selectively removed by plasma etching, solvent etching, developer etching using alkaline aqueous solutions, etc. In an organic monomer-based block copolymer, one block may be made of a polyolefin monomer (including polydiene), a polyether (including poly(oxyalkylene), such as poly(oxyethylene), poly(oxypropylene), poly(oxybutylene)) or a mixture thereof; and the other block may be made of a different monomer, including poly((meth)acrylate), polystyrene, polyester, polysiloxane, polygermanane, and / or mixtures thereof. These blocks in the polymer chain may each contain one or more repeating units derived from the monomer. Different types of block copolymers may be used depending on the type of desired pattern and the method used. For example, they may include diblock copolymers, triblock copolymers, ternary copolymers, or multiblock copolymers. The blocks of these block copolymers may themselves consist of homopolymers or copolymers. Different types of block copolymers can also be used for self-assembly, such as dendritic block copolymers, hyperbranched block copolymers, grafted block copolymers, organic diblock copolymers, organic multiblock copolymers, linear block copolymers, star-shaped block copolymers, amphiphilic inorganic block copolymers, amphiphilic organic block copolymers, or mixtures of at least different types of block copolymers.

[0132] The blocks of organic block copolymers can contain monomers derived from monomers such as C-2 to C-30 olefins, (meth)acrylate monomers derived from C-1 to C-30 alcohols, or repeating units containing inorganic monomers (including those based on Si, Ge, Ti, Fe, and Al). Monomers based on C-2 to C-30 olefins can form highly etch-resistant blocks, alone or in combination with another olefin monomer. Specific examples of this type of olefin monomer are ethylene, propylene, 1-butene, 1,3-butadiene, isoprene, dihydropyran, norbornene, maleic anhydride, styrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-methylstyrene, α-methylstyrene, or mixtures thereof. Examples of highly etchable units can be derived from (meth)acrylate monomers, such as (meth)acrylate, (meth)methyl acrylate, (meth)ethyl acrylate, (meth)propyl acrylate, (meth)isopropyl acrylate, (meth)butyl acrylate, (meth)isobutyl acrylate, (meth)pentyl acrylate, (meth)isopentyl acrylate, (meth)neopentyl acrylate, (meth)hexyl acrylate, (meth)cyclohexyl acrylate, (meth)isobornyl acrylate, (meth)hydroxyethyl acrylate, or mixtures thereof.

[0133] Illustrative examples of block copolymers containing one type of highly etch-resistant repeating units are polystyrene blocks containing only repeating units derived from styrene and another type of highly etchable polymethyl methacrylate blocks containing only repeating units derived from methyl methacrylate. Together, these form the block copolymer poly(styrene-b-methyl methacrylate), where b refers to a block.

[0134] Non-limiting examples of block copolymers that can be used in the chemical epitaxial method described herein, comprising patterned neutral layer regions and patterned novel crosslinked pinned MAT layer regions, include poly(styrene-b-vinylpyridine), poly(styrene-b-butadiene), poly(styrene-b-isoprene), poly(styrene-b-methyl methacrylate), poly(styrene-b-alkenyl aromatics), poly(isoprene-b-ethylene oxide), poly(styrene-b-(ethylene-propylene)), and poly(ethylene oxide). The polymers include alkyl-β-caprolactone, poly(butadiene-β-ethylene oxide), poly(styrene-β-(meth)acrylate tert-butyl ester), poly(methyl methacrylate-β-methacrylate tert-butyl ester), poly(ethylene oxide-β-propylene oxide), poly(styrene-β-tetrahydrofuran), poly(styrene-β-isoprene-β-ethylene oxide), poly(styrene-β-dimethylsiloxane), poly(methyl methacrylate-β-dimethylsiloxane), or combinations containing at least one of the above block copolymers. All these polymeric materials share the common feature of containing at least one block rich in repeating units resistant to etching techniques commonly used in IC device manufacturing and at least one block that is rapidly etched under these same conditions. This allows the oriented self-assembling polymer to transfer patterns onto the substrate to influence pattern correction or pattern multiplication.

[0135] In the chemical epitaxy method described in this paper, the suitable molecular weight property of the block copolymer is the weight-average molecular weight (M). w In the range of approximately 3,000 to approximately 500,000 g / mol and number-average molecular weight (M... n The value ranges from approximately 1,000 to approximately 60,000 and exhibits polydispersity (M). w / M n The molecular weight is approximately 1.01 to approximately 6, or 1.01 to approximately 2, or 1.01 to approximately 1.5. w and M n It can be determined, for example, by gel permeation chromatography using a universal calibration method, calibrated according to polystyrene standards. This ensures that, when applied to a given surface, the polymer blocks have sufficient mobility to undergo self-assembly, either spontaneously or through pure heat treatment, or through assisted heat treatment by absorbing solvent vapor into the polymer backbone to increase the flow of the segments and thus enable self-assembly to occur.

[0136] Solvents suitable for dissolving these block copolymers to form films can vary depending on the solubility requirements of the block copolymers. Examples of solvents used for block copolymer assemblies include propylene glycol monomethyl ether acetate (PGMEA), ethoxyethyl propionate, anisole, ethyl lactate, 2-heptanone, cyclohexanone, amyl acetate, n-butyl acetate, methyl n-pentyl ketone (MAK), γ-butyrolactone (GBL), toluene, and combinations thereof. In one embodiment, particularly useful casting solvents include propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), or combinations thereof.

[0137] The block copolymer composition may contain additional components and / or additives selected from: inorganic polymers; additives, including small molecules, inorganic molecules, surfactants, photoacidogens, thermoacidogens, quenchers, hardeners, crosslinking agents, chain extenders, etc.; and combinations comprising at least one of the foregoing, wherein one or more additional components and / or additives are co-assembled with the block copolymer to form a block copolymer assembly.

[0138] A block copolymer composition is applied to a patterned substrate containing patterned neutral layer regions, and regions of a patterned novel copolymer pinned MAT layer are defined on the surface by conventional photolithography as described above, wherein the neutral layer surface is formed of the material as previously described and the pinned MAT layer is formed of a composition containing the novel copolymer described herein. After solvent application and removal, the block copolymer then undergoes self-assembly in a specific pattern orientation formed on the neutral layer by conventional photolithography through patterned chemical differences on the substrate surface created by the conventional photolithography process. If multiple phase boundaries are formed between features defined by conventional photolithography, pattern correction maintaining the same resolution and / or pattern multiplication can be achieved, depending on the relationship between the relative pitch of the pattern after pattern transfer and the microphase separation distance in standard IC processing.

[0139] Applying block copolymers via spin coating (including spin drying) is sufficient to form self-oriented block copolymer assemblies. Other methods for forming self-oriented domains can occur during application, baking, annealing, or a combination of one or more of these operations. In this way, oriented block copolymer assemblies with microphase-separated domains, comprising cylindrical microdomains oriented perpendicular to a neutral surface, or lamellar domains oriented perpendicular to a neutral surface, are prepared by the above methods. Typically, the microphase-separated domains are lamellar domains oriented perpendicular to a neutral surface, providing parallel line / space patterns in the block copolymer assembly. Such oriented domains exhibit ideal thermal stability under further processing conditions. Therefore, after coating a layer comprising a block copolymer assembly containing a useful diblock copolymer such as poly(styrene-b-methyl methacrylate) and optionally baking and / or annealing, the domains of the block copolymer will form on the neutral surface and remain perpendicular to the neutral surface to provide highly etch-resistant and highly etchable regions on the substrate surface, which can be further patterned in the substrate layer. The oriented self-assembled block copolymer pattern is transferred to the underlying substrate using known techniques. In one example, wet etching or plasma etching with optional UV exposure can be used. Acetic acid can be used for wet etching. Standard plasma etching processes can be used, such as oxygen-containing plasma; additionally, argon, carbon monoxide, carbon dioxide, CF4, and CHF3 can be present in the plasma.

[0140] In this invention, the initial negative or positive photoresist pattern used to form the oriented self-assembled pattern can be defined using negative or positive photoresist in either a negative-tone or positive-tone development process, and can be imaged using any conventional lithography technique, such as electron beam, ion beam, X-ray, EUV (13.5 nm), broadband or UV (450 nm-10 nm) exposure, immersion lithography, etc. In one embodiment, the invention is particularly applicable to 193 nm imaging exposure using dry lithography or immersion lithography. For 193 nm lithography, commercially available positive 193 nm photoresists can be used, such as non-limiting examples like AZ AX2110P (available from EMD Performance Materials Corp, Somerville, NJ), photoresists from Shin-Etsu Chemical Corp., JSR Micro from Japan Synthetic Rubber, and other photoresists available from Fujifilm, TOK, etc. These photoresists can be developed using an alkaline aqueous solution containing tetramethylammonium hydroxide after exposure and then baked to obtain a positive-tone pattern, or developed using organic solvents such as methyl ammonium ketone (MAK), butyl acetate, anisole, etc., to obtain a negative-tone pattern. Alternatively, commercially available negative-tone photoresists can be used for 193nm exposure as well.

[0141] The substrates that can be used in the novel coating and chemical epitaxial methods described herein are any substrates required in IC device fabrication. In one example, the substrate is a wafer coated with a high-carbon-content organic layer, upon which is a silicon or titanium coating containing ARC (high resistance to etch by oxygen plasma), allowing the transfer of patterned block copolymer patterns into these coatings. Suitable substrates include, but are not limited to, silicon, silicon substrates coated with metal surfaces, copper-coated silicon wafers, copper, aluminum, polymer resins, silicon dioxide, metals, doped silicon dioxide, silicon nitride (SiN), silicon carbide, tantalum, polycrystalline silicon, ceramics, aluminum / copper mixtures, glass, coated glass; gallium arsenide and other such Group III / V compounds. These substrates may be coated with an anti-reflective coating. The substrate may comprise any number of layers made of the materials described above.

[0142] For this invention, the directional self-assembly of the above-mentioned block copolymers can be achieved using various methods involving pinned chemical epitaxy, novel styrene polymer compositions, and known neutral layers described in US8,835,581, US9,181,449, US9,093,263, US8691925, US20140335324A1, US2016-0122579A1, or US Application No. 14 / 885,328, all of which are incorporated herein by reference in their entirety. This pattern can then be further transferred to a substrate. In this way, various high-resolution features can be patterned onto the substrate, achieving pattern correction, pattern multiplication, or both.

[0143] As described in more detail in the Examples section, it has been found that compositions comprising the novel random copolymers described herein enable pre-patterning design flexibility when these are used as pinned substrates in chemical epitaxy methods. Conventional pinned MAT layers containing high levels of nonpolar aromatic monomers have low etch rates, which can lead to residue problems during pre-patterning in chemical epitaxy. The novel materials disclosed herein can potentially eliminate residues due to their ease of etching, resulting in uniform assembly of the lines and spatial CDs of the block copolymer domains.

[0144] Crosslinkable polystyrene pinning MAT is used for developing pre-patterns for L / SDSA. Although the LiNe flow process of DSA has been effectively patterned using copolymers composed of styrene and vinylbenzocyclobutene, the crosslinked underlayer is difficult to etch after resist patterning and during pattern trimming after DSA pattern transfer. This difficulty in patterning and poor morphology is due to the low etch rate of this copolymer, composed of completely hydrophobic styrene repeating units. An alternative pinning material was prepared by adding acrylate monomers, which achieves higher etch rates and improved morphology. This novel material also improves the BCP structure, reduces edge misalignment, and exhibits almost no CD difference between guide and non-guide lines. Example

[0145] Photolithography was performed using an ASML (ASML Veldhoven, De Run 65015504 DR, Veldhoven The Netherlands) NXT 1950i. Etching experiments were performed using a LAM (4650 Cushing Parkway Fremont, CA94538 USA) Kiyo E5. Spin coating and development of the film and pattern were performed using a SCREEN (SCREEN semiconductor solutions Co., Ltd., Tenjinkita-machi 1-1, Teranouchi-agaru 4-chome, Horikawa-dori, Kamigyo-ku, Kyoto, JAPAN), a SOKUDO DUO track, or a TEL (Tokyo Electrons Ltd., Akasaka BizTower 3-1 Akasaka 5-chome, Minato-ku, Tokyo 107-6325) ACT-12. The photoresist pattern was stripped using a SCREEN (SCREEN Semiconductor Solutions Co., Ltd., Tenjinkita-machi 1-1, Teranouchi-agaru 4-chome, Horikawa-dori, Kamigyo-ku, Kyoto, JAPAN) AQUASPIN. Scanning electron micrographs were obtained using a Hitachi H-5000 (Hitachi High Technologies America Inc., 10 North Martingale Road, Suite 500 Schaumburg, Illinois 60173-2295).

[0146] Synthesis of Block Copolymers and Neutral Brushes

[0147] Neutral Substrate Synthesis Example 1: Synthesis of P(S-co-PMMA) Brush Neutral Layer Polymer

[0148] A 2000 ml flask equipped with a condenser, temperature controller, heating mantle, and mechanical stirrer was constructed. 400 g (3.84 mol) styrene (S), 401 g (4 mol) methyl methacrylate (MMA), 9.44 g (0.016 mol) nitrooxy initiator, and 534 g anisole were added to the flask. The mechanical stirrer was turned on and set to approximately 120 rpm. The reaction solution was then degassed by vigorously bubbling nitrogen through the solution at room temperature for approximately 30 minutes. After 30 minutes of degassed treatment, the heating mantle was turned on and the temperature controller was set to 140 °C, and the stirred reaction mixture was maintained at this temperature for 20 hours. Afterward, the heating mantle was turned off and the reaction solution was cooled to approximately 40 °C. The reaction mixture was then poured into 13 L of isopropanol, with mechanical stirring during the addition. During this addition, the polymer precipitated. The precipitated polymer was collected by filtration. The collected polymer was dried in a vacuum oven at 40 °C. Approximately 500 g of polymer was obtained. The dried polymer was dissolved in 1500 g THF and then filtered through a 0.2 μm nylon filter. The filtered solution was then precipitated again in 13 L of stirred methanol solution, and the precipitated polymer was collected and dried under vacuum at 40 °C as previously described. In this manner, 400 g (48% yield) of polymer was obtained after drying. The M of this polymer... w It is approximately 15k and the polydispersity index (PDI) is 1.5.

[0149] Synthesis of a block copolymer 1: an anionic copolymer of styrene and methyl methacrylate

[0150] P(Sb-MMA)(21K-b-24K) was synthesized using the same procedure as described in the previous examples. Briefly, 20 g (0.192 mol) of styrene was polymerized with 0.68 mL (1.4 M solution) of sec-butyllithium. Then, a solution of 0.196 g (0.0011 mol) of 1,1'-diphenylethylene (DPE) in 2.5 mL of anhydrous toluene was added to the reactor via an ampoule. The reaction mixture changed from orange to deep brick red, indicating that the active site of the styrene-based lithium was converted to a delocalized DPE adduct carbanion. After stirring for 2 minutes, a small amount (2 mL) of the reaction mixture was taken for PS block molecular weight analysis. Methyl methacrylate (22.85 g, 0.23 mol) was then added via an ampoule. The reaction was terminated with 1 mL of degassed methanol after 30 minutes. The block copolymer was recovered by precipitation in an excess of isopropanol containing 10% water (5 times the amount of the polymer solution), filtered, and dried under vacuum at 70°C for 12 hours to give 40 g of P(Sb-MMA) (yield 94%).

[0151] Comparative Example 1: Synthesis of a copolymer of styrene and 4-vinylbenzocyclobutene (Comparative Polymer 1)

[0152] 660.3 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a 3 L four-necked flask equipped with a condenser, temperature controller, and mechanical stirrer, fixed in a heating mantle. 65 g of vinylbenzocyclobutene (VBCB), 11.23 g of azobisisobutyronitrile (AIBN), and 900 g of 2-butanone (MEK) were added to the flask. The reaction solution was degassed by vigorously bubbling nitrogen through the solution with mechanical stirring at room temperature for approximately 30 minutes. The reaction was then heated to 80 °C under nitrogen for 20 hours, followed by cooling to 40 °C. The reaction mixture was then precipitated in isopropanol, filtered, and dried in a vacuum oven. w It is 18,500 g / mol, PD 1.8.

[0153] Synthesis of novel copolymers

[0154] Novel copolymers (Examples 1 to 13) were prepared in 60% to 70% yields by free radical copolymerization of polystyrene and 4-vinylbenzocyclobutene (VBCB) with polar methacrylate monomers, as described in Tables 1 and 2. These copolymers, due to their higher oxygen atom content, are more susceptible to plasma etching. However, further introduction of these polar methacrylate monomers into these copolymers reduces the hydrophobicity of the polymer, resulting in reduced pinning strength. Tables 1 and 2 show detailed information on the properties of these novel copolymers and the layers formed therefrom, representing an optimal trade-off between retaining the desired hydrophobicity and increasing etching capability. For comparison, these tables also show data for Comparative Example 1, a copolymer of styrene and 4-vinylbenzocyclobutene, which exhibits higher resistance to plasma etching and reduced etching capability due to the lack of oxygen atoms.

[0155] Example 1 Synthesis of Copolymer 1

[0156] 0.86 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.56 g of vinylbenzocyclobutene (VBCB), 2.13 g of butyl methacrylate (99%, stabilized with hydroquinone monomethyl ether), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 18 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0157] Example 2 Synthesis of copolymer 2

[0158] 41.68 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 6.51 g of vinylbenzocyclobutene (VBCB), 7.11 g of butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was then vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 18 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven.

[0159] Example 3 Synthesis of copolymer 3

[0160] 40.62 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, followed by 4.56 g of vinylbenzocyclobutene (VBCB), 10.66 g of butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was then vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 18 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0161] Example 4 Synthesis of copolymer 4

[0162] 43.23 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.56 g of vinylbenzocyclobutene (VBCB), 7.11 g of n-butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100.21 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0163] Example 5 Synthesis of copolymer 5

[0164] 39.07 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 6.53 g of vinylbenzocyclobutene (VBCB), 10.65 g of n-butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0165] Example 6 Synthesis of copolymer 6

[0166] 36.50 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, and 9.77 g of vinylbenzocyclobutene (VBCB), 10.67 g of n-butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole were added. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0167] Example 7 Synthesis of copolymer 7

[0168] 33.86 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, and 13.08 g of vinylbenzocyclobutene (VBCB), 10.66 g of n-butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole were added. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0169] Example 8 Synthesis of copolymer 8

[0170] 46.87 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.58 g of vinylbenzocyclobutene (VBCB), 2.66 g of benzyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 101.21 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0171] Example 9 Synthesis of copolymer 9

[0172] 43.24 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.57 g of vinylbenzocyclobutene (VBCB), 8.83 g of benzyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 102.21 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0173] Example 10 Synthesis of copolymer 10

[0174] 40.63 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.56 g of vinylbenzocyclobutene (VBCB), 13.22 g of benzyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 101.25 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 17 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in Table 1.

[0175] Example 11 Synthesis of copolymer 11

[0176] 40.62 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.56 g of vinylbenzocyclobutene (VBCB), 10.66 g of butyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was then vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 18 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in the table.

[0177] Example 12 Synthesis of copolymer 12

[0178] 41.68 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 6.51 g of vinylbenzocyclobutene (VBCB), 5.71 g of ethyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was then vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 18 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. The composition and molecular weight are shown in the table.

[0179] Example 13 Synthesis of copolymer 13

[0180] 40.62 g of styrene (≥99%, stabilized with 4-tert-butylcatechol) was weighed into a round-bottom flask, along with 4.56 g of vinylbenzocyclobutene (VBCB), 8.56 g of ethyl methacrylate (99%, stabilized with monomethyl ether hydroquinone), 0.41 g of azobisisobutyronitrile (AIBN), and 100 g of anisole. The flask was sealed with a three-way stopper, briefly degassed, and rinsed with argon. The mixture was then vacuum-frozen and thawed three times in a liquid nitrogen bath to remove residual moisture and impurities. The reaction mixture was then heated to 73 °C under nitrogen for 18 hours. The reaction mixture was then precipitated in isopropanol, filtered, and dried overnight in a vacuum oven. Composition and molecular weight are shown in the table.

[0181] Table 1

[0182] Example 1 P(S-VBCB-BuMA) 90-7-3 36.2 1.32 Example 2 P(S-VBCB-BuMA) 80-10-10 38.9 1.45 Example 3 P(S-VBCB-BuMA) 78-7-15 39.5 1.5 Example 4 P(S-VBCB-BuMA) 83-7-10 37.6 1.52 Example 5 P(S-VBCB-BuMA) 75-10-15 37.8 1.63 Example 6 P(S-VBCB-BuMA) 70-15-15 39.4 1.59 Example 7 P(S-VBCB-BuMA) 65-20-15 36.7 1.6 Example 8 P(S-VBCB-BnMA) 90-7-3 34 1.7 Example 9 P(S-VBCB-BnMA) 83-7-10 37 1.65 Example 10 P(S-VBCB-BnMA) 78-7-15 40.7 1.64 Example 11 P(S-VBCB-EMA) 90-7-3 33.4 1.65 Example 12 P(S-VBCB-EMA) 80-10-10 34.3 1.59 Example 13 P(S-VBCB-EMA) 78-7-15 38.5 1.6 Comparative Example 1 P(S-VBCB) 93-7-0 18.7 2

[0183] Photolithography and chemical epitaxy methods

[0184] Figure 1The method used for the novel pinned MAT layer composition described herein and the comparative layer of comparative polymer 1 is illustrated. Specifically, this illustrates LiNe flow DSA for line and space multiplication schemes. The conditions for pre-patterning development and DSA are as follows: a 13 nm substrate with 13 nm thick SiN on silicon is used, and the following crosslinkable pinning material, Comparative Example 1 and Examples 1, 2 or 3, is coated with a film thickness of 8 nm and cured in N2 at 315°C for 5 minutes to form a crosslinked pinned MAT layer. The photolithography of this pinned MAT layer is performed using AIM-5484PTD photoresist (JSR Micro, Inc. 1280N. Mathilda Ave. Sunnyvale, CA 940890) with a film thickness of 95 nm, and exposure is performed using an ASML 1970i (iArF scanner) to form a photoresist pattern exposing the underlying crosslinked pinned MAT layer. The finishing etching conditions employed plasma etching with N2O2 etching chemicals to remove cross-linked pinning material from areas not covered by patterned photoresist.

[0185] Formulation preparation:

[0186] The dried copolymer, neutral layer 1, and block copolymer 1 prepared in the above examples (Examples 1 to 13) and Comparative Example 1 were weighed separately in vials and dissolved in PGMEA at 2% by weight. The vials were placed on a shaker overnight and then filtered through a PTFE syringe filter.

[0187] Formulation crosslinking to form a pinned MAT layer and neutral assessment:

[0188] Formulations containing different copolymers (Examples 1 to 13 and Comparative Example 1) were individually coated onto Si wafers at sufficient rotational speeds to obtain film thicknesses of approximately 8 nm. The wafers were then baked at 250°C under nitrogen for one hour, followed by rinsing with EBR solvent for two minutes to form the pinned MAT layer to be evaluated. The thicknesses of these films were measured by ellipsometry before and after EBR rinsing to determine film loss.

[0189] To determine neutrality, the pinned MAT layers were evaluated as follows: they were coated with a neutral polymer formulation (neutral layer 1), then coated with a formulation containing the formulations of Examples 1 to 13 or Comparative Example 1 and baked at 250°C for 30 minutes under nitrogen, then rinsed with EBR solvent (AZ EBR solvent, EMD PM Branchburg, 70 Meister Ave, Somerville, NJ 08876) for 2 minutes and baked at low temperature to dry. The film thickness was measured before and after coating the neutral layer to determine film growth, if any. The film was then coated with a formulation containing block copolymer 1 to form a 35 nm film, which was then annealed at 250°C for 30 minutes under nitrogen. The film was then imaged by CDSEM to determine the structure of the BCP for neutrality evaluation. All tested polymers showed little to no orientation in the BCP film, indicating that the polymer was non-neutral.

[0190] Photoresist stripping was performed using Orgasolv STR 301 (BASF, 100 Park Avenue, Florham Park, NJ 07932, USA). The resulting patterned crosslinked pinned MAT layer was then coated with a composition containing a neutral brush (neutral brush 1) and baked at 250°C for 30 minutes, followed by rinsing with RER 600 (RER 600, Fujifilm, 200 Summit Lake Drive, Valhalla, NY 10595) for 30 minutes to form a pattern comprising neutral layer regions and pinned MAT layer regions. This pattern was then coated with a composition containing block copolymer 1 and baked at 250°C for x minutes to form a baked film with a thickness of 35 nm, followed by annealing at 250°C to influence the directional self-assembly of the block copolymer domains.

[0191] Table 2 shows a comparison of coatings obtained using novel copolymers incorporating 3 mol% to 15 mol% polar methacrylate monomers. These properties include film thickness before and after rinsing, k-value at 193 nm, and WCA (water contact angle). The table shows that the WCA and k-values ​​of the novel copolymers in Examples 1 to 13 are similar to those in Comparative Example 1, a copolymer of styrene and 4-vinylbenzocyclobutene. This similarity indicates that these materials have pinning properties similar to Comparative Example 1, although they are endowed with a significant oxygen content by the introduction of polar methacrylate monomers that can promote plasma etching. Therefore, due to the minimal variation in water contact angle and k-value shown in Table 2, novel copolymers containing polar methacrylate monomers (Examples 1 to 13) can be coated to form novel hydrophobic crosslinkable underlayer pinning MAT materials for the polystyrene domain in PS-b-PMMA DSA.

[0192] Table 2

[0193] Example 1 7.79nm + 0.63A 7.64nm + 0.36A 0.8174 86.6 Example 2 7.58nm+0.35A 7.45nm + 0.46A 0.72524 85 Example 3 8+0.1nm 8±0.1nm 0.7143 85±1.5 Example 4 8±0.1nm 8±0.2nm 0.7563 86±0.9 Example 5 7.8±0.1nm 7.9±0.1nm 0.698 84±0.3 Example 6 7.9±0.1nm 7.9±0.1nm 0.673 85±1.2 Example 7 8.1±0.1nm 8.1±0.2nm 0.6553 85±1.2 Example 8 7.7 + 0.1 nm 7.7±0.1nm 0.84148 87±1.2 Example 9 7.6 + 0.09nm 7.6±0.1nm 0.8209 85±0.9 Example 10 7.4 + 0.1 nm 7.4±0.07nm 0.8051 84±0.6 Comparative Example 1 8.2+0.2nm 8.2±0.1nm 0.86042 87±0.3

[0194] Figure 2 A comparison of coatings made from Reference Comparative Example 1 is shown, demonstrating that the material is not neutral to styrene and methyl methacrylate block polymer (PS-b-PMMA) coatings, and that the new materials of Examples 1, 2, and 3 (1 to 3 with different concentrations of polar n-butyl methacrylate monomer) exhibit similar behavior.

[0195] The addition of 15 mol% n-butyl methacrylate resulted in a 10% increase in etching rate compared to Comparative Example 1, observed in the styrene-4-vinylbenzocyclobutene copolymer. This led to a change in the morphology of the stapled bands, with more vertical sidewalls compared to the standard, thus reducing the impact of the sidewalls on DSA performance. DSA processes on polymers with 15% n-BuMA showed minimal dimensional differences between guided and unguided lines after N2 / O2 plasma etching to remove PMMA.

[0196] Compared to the standard pinned MAT layer derived from Comparative Example 1, trimming etching or dry etching improved the results by up to 4-15%.

[0197] Therefore, depending on the composition of the polar comonomers in the novel copolymer Examples 1 to 13, adjustable dry etching resistance of the pinned MAT layer has been achieved.

[0198] The PMMA space CD on each photolithographic spacing can more uniformly reduce the polystyrene line CD.

[0199] Crosslinkability and non-neutrality testing in Examples 1, 2, and 3:

[0200] The crosslinkability of the copolymers was tested using a film of approximately 8 nm, and the film was baked at 250 °C for 30 minutes under nitrogen. The film thickness was measured, and the film was immersed in PGMEA solvent for testing. The results showed that these copolymers formed a well-crosslinkable film and remained stable even after immersion in PGMEA, indicating crosslinking (Table 2).

[0201] Specifically, the crosslinking immersion test of the MAT pinning layer formed from copolymers of Examples 1 to 10 or formulations containing Comparative Example 1 was performed by coating on Si and then baking (250°C / 30 min / N2 2 min), followed by rinsing with EBR70 / 30.

[0202] After crosslinking these copolymers to form the MAT layer to be tested, a neutral underlayer (neutral layer 1, a hydroxyl-terminated copolymer of methyl methacrylate and styrene, PS 50 mol%) was applied by baking and rinsing. Since the crosslinked MAT pinning layers formed from copolymers of Examples 1 to 13 do not have any functional groups that react with the brush neutral material, no reaction occurs, and there are no MAT pinning layers formed from formulations containing Examples 1 to 13. It is expected that these surfaces should not have any neutral grafting. This was verified by coating the diblock copolymer and baking to develop any vertically morphological fingerprint block copolymer domains. None of these copolymers showed fingerprint morphology, but rather a parallel morphology, indicating that the surface is hydrophobic and can selectively pin the polystyrene domains of the PS-b-PMMA diblock copolymer ( Figure 2 ).

[0203] Etching rate comparison:

[0204] The polymer was dissolved in PGMEA and coated onto an 8-inch silicon wafer at approximately 100 nm. The wafer was then soft-baked at 110 °C for one minute and annealed at 250 °C for 30 minutes under nitrogen. The overall etching rate of the polymer film was determined by O2 (50 sccm) plasma etching from 0 to 60 seconds (in 10-second increments), and the film thickness was determined by ellipsometry.

[0205] Table 3 shows a comparison of the normalized etch rates of MAT pinning layers formed from formulations containing polar methacrylate monomers in Examples 1 to 13, and MAT pinning layers formed from a copolymer of styrene and 4-vinylbenzocyclobutene (reference material, Comparative Example 1) without polar methacrylate monomers.

[0206] These etching rates were determined by the slope of the plotted film thickness versus etching time to give an overall etching rate in nm / s. The rates were then normalized by dividing by the etching rate of the reference material (Comparative Example 1). The normalized etching rates are shown in Table 3.

[0207] Figure 3 The comparison between the etching rate and the normalized etching rate shows the overall etching improvement of the series of Examples 1 to 13 compared to Comparative Example 1. (Conditions: ACT12: 110°C / 1 min, 250°C / 30 min (N2). Trion etching machine: pressure = 70 mT; top / bottom (W) = 50 / 50; O2 (sccm) = 50).

[0208] like Figure 3As shown, the etching rate increases with the addition of the polar component to the novel copolymers in the series of Examples 1 to 13. This is due to the increased degradation rate of the polar portion during etching compared to the aromatic portion. The etching rate can be further improved by increasing the ratio of the polar portion to the non-polar portion in the polymer.

[0209] like Figure 4 As shown, after annealing at 250°C for 60 minutes under nitrogen, the etching rate and normalized etching rate of the comparative samples were also determined. This indicates a similar improvement in etching capability compared to Comparative Example 1, the copolymer of styrene and 4-vinylbenzocyclobutene. (Conditions: ACT12: 110°C / 1 min, 250°C / 30 min (N2). Trion etching machine: pressure = 70 mT; top / bottom (W) = 50 / 50; O2 (sccm) = 50).

[0210] Figure 4 The etching rates of the reference material relative to the examples and comparative examples are shown. As shown in the figure, the addition of the polar portion increased the etching rate compared to the reference material, and the subsequent increase in the polar to non-polar loading ratio further enhanced the etching rate. However, the structure of the polar monomer has a significant impact on the etching rate. Adding similar amounts of different polar compounds resulted in very different etching rates, i.e., a comparison of the etching rates between Example 2 and Comparative Example 2. A summary of the normalized etching rates of each synthesized copolymer compared to Comparative Example 1 is shown in Table 1.

[0211] Table 3 shows the normalized etch rates of the novel copolymers containing polar methacrylate monomers, Examples 1 to 1, and Comparative Example 1, a copolymer of styrene and 4-vinylbenzocyclobutene.

[0212] Table 3

[0213]

[0214] DSA process window assessment:

[0215] The DSA process window was inspected on a patterned SiN wafer to evaluate different combinations of spacing and etch dose. The DSA pre-patterns used for DSA were fabricated via photolithography using a LiNe flow process, such as... Figure 1As shown. In short, SiN (13nm) is coated onto a Si wafer, then a crosslinkable PS pad is coated at 8nm, and then baked at 315°C for 5 minutes under nitrogen. Guide lines are formed using AIM-5484PTD photoresist (95nm) imaged with ASML 1970i, followed by N2O2 trimming etching and stripping with STR Orgasolv and IPA rinsing to form a 90nm pitch guide pattern for the associated xPS material. A formulation with neutral layer polymer 1 (neutral brush) is coated onto the wafer, baked at 250°C for 30 minutes, and then excess portions are rinsed off with RER 600 to form a DSA chemical pre-pattern. Finally, a formulation containing block copolymer 1 (PS 43%, FT35nm) is coated and annealed at 250°C for 5 or 30 minutes.

[0216] The critical dimension (CD) of the formed BCP line was determined for after-development inspection (ADI), before etching, and after etching (AEI). The figure below shows the CD as a function of dose (mJ / cm) observed in Examples 1, 2, and 3 containing polar methacrylate monomers relative to Comparative Example 1 using non-polar methacrylate monomers. 2 The variation is as follows. Compared with other materials, Example 3 has a larger CD in every case.

[0217] Figure 5 The photolithography performance of P90nm was compared. Example 3 induced a larger ADI CD than other novel copolymers.

[0218] Figure 6 The photolithography performance of P90nm was compared, and it was again shown that Example 3 induced a larger etch-after inspection (AEI) CD compared to Example 1, Example 2 or Comparative Example 1.

[0219] Figure 7 The DSA process windows of the novel pinned MAT pinning layers derived from Examples 1, 2, and 3 are shown compared to the MAT pinning layer derived from Comparative Example 1. The DSA dislocation rate was evaluated after N2O2 etching to remove PMMA. The process window area was found to be similar for each material, although the formulation based on Example 3 differed slightly. This implies that despite the increased polarity and hydrophilicity of the pinning materials, the polymers are non-neutral, and their pinning strength is sufficient to keep the DSA process window unaffected.

[0220] DSA critical size (CD) change:

[0221] Figure 8The average CD and 3σ of the DSA lines formed using Comparative Example 1 and Examples 1, 2, and 3 are shown. This indicates that the DSA line widths on guided (pinned) and unguided (unpinned) regions were also compared. The line CD value was determined by averaging 10 lines from each of the 30 images. The figure below shows the line CD and 3σ values ​​in the images. No significant differences were observed between the different CD values. Figure 9 Examples of guided and unguided DSA lines formed and used in the CD assessment described above are shown.

Claims

1. A random copolymer having repeating units comprising repeating units of structures (I), (II), and (III), wherein R1 and R2 are independently C-1 to C-4 alkyl groups, x and y are independently the number of R1 and R2, which are independently integers from 0 to 3, R3 is a C-1 to C-4 alkyl group, and R4 is selected from C-2 to C-10 primary alkyl groups, or comprises an aromatic moiety consisting of a substituted or unsubstituted biphenyl moiety, a substituted or unsubstituted phenyl moiety, and a substituted or unsubstituted benzyl moiety, and m, n, and o are the number of repeating units of structures (I), (II), and (III), respectively, wherein the mol% of repeating units of structure (I) ranges from 60 mol% to 95 mol%. The molar percentage of repeating units of structure (II) ranges from 5 mol% to 25 mol%, and the molar percentage of repeating units of structure (III) ranges from 2 mol% to 18 mol%, wherein if other different repeating units are present, the sum of the molar percentages of these repeating units is less than 100 mol%, or if only repeating units of structures (I), (II), and (III) are present, it is equal to 100 mol%. Furthermore, the polydispersity of the random copolymer ranges from 1.25 to 1.80, and the Mw ranges from 30,000 to 45,000 Daltons, and the random copolymer does not have reactive end groups containing benzyl alcohol moieties. 。 2. The random copolymer of claim 1, wherein the repeating units are substantially composed of repeating units of structures (I), (II) and (III).

3. The random copolymer of claim 1 or 2, wherein the repeating units are composed of repeating units of structures (I), (II) and (III), wherein the sum of the molar percentages of repeating units (I), (II) and (III) is equal to 100 moles.

4. The random copolymer of claim 1 or 2, wherein the repeating unit of structure (III) ranges from 2.5 mol% to 16 mol%.

5. The random copolymer of claim 1 or 2, wherein the repeating units of structure (II) range from 6 mol% to 23 mol%.

6. The random copolymer of claim 1 or 2, wherein the repeating units of structure (I) range from 62 mol% to 93 mol%.

7. The random copolymer of claim 1 or 2, wherein the repeating units of structure (I) range from 60 mol% to 90 mol%, the repeating units of structure (II) range from 7 mol% to 20 mol%, and the repeating units of structure (III) range from 3 mol% to 15 mol%.

8. The random copolymer of claim 1 or 2, wherein x is 0.

9. The random copolymer of claim 1 or 2, wherein y is 0.

10. The random copolymer of claim 1 or 2, wherein x and y are 0.

11. The random copolymer of claim 1 or 2, wherein R3 is CH3.

12. The random copolymer of claim 1 or 2, wherein R4 is a C-2 to C-10 primary alkyl group.

13. The random copolymer of claim 1 or 2, wherein R4 is a C-3 to C-7 primary alkyl group.

14. The random copolymer of claim 1 or 2, wherein R4 is n-butyl.

15. The random copolymer of claim 1 or 2, wherein R4 is a C-2 to C-6 primary alkyl group.

16. The random copolymer of claim 1 or 2, wherein R4 is n-propyl.

17. The random copolymer of claim 1 or 2, wherein R4 is ethyl.

18. The random copolymer of claim 1 or 2, wherein R4 is a benzyl moiety.

19. The random copolymer of claim 1 or 2, wherein R4 is benzyl.

20. The random copolymer of claim 1 or 2, wherein R4 is a substituted phenyl moiety.

21. The random copolymer of claim 1 or 2, wherein R4 is phenyl.

22. The random copolymer of claim 1 or 2, wherein R4 is a substituted biphenyl.

23. The random copolymer of claim 1 or 2, wherein R4 is an unsubstituted biphenyl moiety.

24. The random copolymer of claim 1 or 2, wherein R4 is [1,1'-biphenyl-4-yl].

25. The random copolymer of claim 1 or 2, wherein the repeating unit has structures (Ia), (IIa) and (IIIa); 。 26. The random copolymer of claim 1 or 2, wherein the repeating unit has structures (Ia), (IIa) and (IIIa-1); 。 27. The random copolymer of claim 1 or 2, wherein the repeating unit has structures (Ia), (IIa) and (IIIb); 。 28. The random copolymer of claim 1 or 2, wherein the repeating unit has structures (Ia), (IIa) and (IIIc); 。 29. The random copolymer of claim 1 or 2, wherein the repeating unit has structures (Ia), (IIa) and (IIId); 。 30. A composition comprising any one of claims 1 to 29, a random copolymer and an organic spin-coating solvent.

31. A method for forming a copolymer crosslinking layer on a substrate, comprising the following steps: a) Forming a coating of the composition of claim 30 on a substrate; b) Heat the coating at a temperature in the range of 90°C to 180°C to remove the solvent; c) Heating the coating at a temperature in the range of 200°C to 350°C to form a crosslinked copolymer coating.

32. A chemical epitaxy method using the directional self-assembly of block copolymer layers to form an image, comprising the following steps: a-1) A graftable neutral layer polymer precursor is coated onto a substrate to form coating 1; b-1) Heat coating 1 at a temperature of 90°C to 180°C to remove the solvent; c-1) Heat the coating 1 after step b-1) at a temperature of 200°C to 350°C to affect the grafting; d-1) Treat coating 1 after step c-1) with an organic solvent to remove the ungrafted neutral layer polymer, leaving an insoluble grafted neutral layer on the substrate. e-1) Coating a negative photoresist layer onto the grafted neutral layer; f-1) A negative pattern is formed in the photoresist layer, thereby forming a region in which the grafted neutral layer is covered or not covered by the photoresist, wherein the pattern in the photoresist includes small nanoscale repeating patterns and large regions that do not contain nanoscale repeating patterns after the photoresist is removed during imaging. g-1) Etching to remove the neutral layer areas not covered in step f-1), leaving the substrate exposed in these areas; h-1) After step g-1), the photoresist is peeled off from the substrate, leaving a patterned substrate, wherein the substrate areas not covered by the photoresist in step f-1) do not have a grafted neutral layer and the areas covered by the photoresist in step f-1) retain a grafted neutral layer. i-1) Coating a patterned substrate with the composition of claim 30 to form coating 2; j-1) Heat coating 2 at a temperature of 90°C to 180°C to remove the solvent; k-1) Heat coating 2 at a temperature in the range of 200°C to 350°C to leave an insoluble crosslinked pinned MAT layer in the area of ​​the substrate without a grafted neutral layer, thereby creating a substrate with a pinned MAT layer area and a neutral layer area. l-1) A block copolymer coating comprising etch-resistant styrene blocks and highly etchable aliphatic blocks is applied to a substrate comprising a patterned neutral layer and a pinned MAT layer to create a substrate comprising both a patterned neutral layer and a patterned pinned MAT layer; m-1) The block copolymer coating was annealed until directional self-assembly occurred in the small nanoscale repeating pattern of the substrate, but no vertical orientation of the block polymer domains occurred in the large region containing the cross-linked pinned MAT layer. o-1) Etching the block copolymer to remove the highly etchable blocks of the copolymer and forming repeating nanoscale patterns in the region on the substrate where the directional self-assembly of the block copolymer occurs in step m-1).

33. A chemical epitaxial method using the directional self-assembly of block copolymer layers to form an image, comprising the following steps: a-2) Forming a crosslinkable or both crosslinkable and graftable neutral layer polymer precursor coating on a substrate; b-2) Heating the crosslinkable neutral polymer layer precursor coating or the crosslinkable and graftable precursor coating at a temperature of 90°C to 180°C to remove the solvent; c-2) Heating a crosslinkable neutral layer polymer precursor coating or a coating precursor coating that is both crosslinkable and graftable at a temperature of 200°C to 330°C to form a crosslinked neutral layer or a crosslinked and grafted neutral layer. d-2) A coating of photoresist layer is provided on a cross-linked neutral layer or on a cross-linked and grafted neutral layer; e-2) A negative pattern is formed in the photoresist layer, thereby forming a region in which the cross-linked or cross-linked and grafted neutral layer is covered or uncovered by the photoresist, wherein the pattern in the photoresist includes small nano-repeating patterns and large area regions that do not contain nano-sized repeating patterns after the photoresist is removed during imaging. f-2) Use plasma etching to remove the neutral layer regions not covered in step e-2), remove crosslinked or crosslinked and grafted neutral layers, leaving bare substrate in the regions not covered in step e-2). g-2) After step f-2), the photoresist is peeled off from the substrate, leaving a patterned substrate, wherein the substrate areas not covered by the photoresist in step e-2) do not contain a cross-linked or cross-linked and grafted neutral layer, and the areas covered by the photoresist in step f-2) retain a cross-linked or cross-linked and grafted neutral layer. h-2) Coating a patterned substrate with the composition of claim 30 to form coating 3; i-2) Heat coating 3 at a temperature of 90°C to 180°C to remove the solvent; j-2) Heat coating 3 at a temperature in the range of 200°C to 350°C to leave an insoluble crosslinked pinned MAT layer in the area of ​​the substrate without grafted neutral layer, and create a substrate containing the pinned MAT layer area and the neutral layer area. k-2) Apply a block copolymer coating containing etch-resistant styrene blocks and highly etchable aliphatic blocks to a substrate containing a patterned neutral layer and a pinned MAT layer; l-2) Anneal the block copolymer layer until directional self-assembly occurs in the small nanoscale repeating pattern of the substrate, but in which vertical orientation of the block polymer domains does not occur in the large region containing the cross-linked pinned MAT layer. m-2) Etching the block copolymer to remove highly etchable blocks of the copolymer and forming repeating nanoscale patterns in the region on the substrate where the block copolymer undergoes directional self-assembly in step l-2).

34. A chemical epitaxial method using the directional self-assembly of block copolymer layers to form an image, comprising the following steps: a-3) Forming a coating of the composition of claim 30 on a substrate to form a film. b-3) Bake the membrane at a temperature of 200°C to 350°C for 1 to 10 minutes to form an insoluble cross-linked pinned MAT layer. c-3) A coating that provides a positive or negative photoresist layer on the crosslinked pinned MAT layer. d-3) Forming a negative or positive image in the negative or positive photoresist layer accordingly, thereby creating cross-linked pinning of areas covered or uncovered by the photoresist. e-3) Use plasma etching to remove the cross-linked pinned MAT layer in the areas not covered in step d-3), leaving the bare substrate and the cross-linked pinned MAT layer in the areas covered in step d-3), forming a patterned cross-linked pinned MAT layer. f-3) Apply the patterned crosslinked pinned MAT layer with a neutral brush coating. g-3) Curing the neutral brush layer coating and washing away the ungrafted neutral layer formed in areas of the substrate not covered by the patterned crosslinked pinned MAT layer with solvent, forming a neutral brush orientation layer on the substrate, thereby forming a chemical epitaxial orientation layer. h-3) A block copolymer solution is coated onto the chemically epitaxially oriented layer to form a block copolymer coating. i-3) Annealing the block copolymer coating to form a oriented self-assembled film of the block copolymer on the chemical epitaxial orientation layer. j-3) Etching the block copolymer to remove the highly etchable blocks of the copolymer and forming repeating nanoscale patterns in the region on the substrate where the directional self-assembly of the block copolymer occurs in step i-3).

35. Use of the copolymer according to any one of claims 1 to 29 or the composition according to claim 30 in a chemical epitaxial process for coating a substrate.

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