A method using a composition containing a solvent mixture to avoid pattern collapse when processing patterned material having line-to-line dimensions of 50 nm or less.
A solvent mixture of alkanol and carboxylic acid ester forms an azeotropic mixture to prevent pattern collapse in sub-50 nm features by minimizing adhesion, ensuring structural stability during drying.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- BASF SE
- Filing Date
- 2024-03-18
- Publication Date
- 2026-06-01
AI Technical Summary
Existing methods fail to effectively prevent pattern collapse in patterned material layers with dimensions of 50 nm or less, particularly in structures with high aspect ratios, due to insufficient consideration of capillary forces and chemical reactions during drying.
A composition comprising an alkanol and a carboxylic acid ester forming an azeotropic mixture is used to minimize irreversible adhesion between patterned structures, preventing pattern collapse during drying.
The composition significantly reduces pattern collapse in sub-50 nm features with high aspect ratios, maintaining structural integrity during the drying process.
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Abstract
Description
[Technical Field]
[0001] The present invention relates, in particular, to a method of using a composition for manufacturing integrated circuit devices, optical devices, micromachines, and mechanical precision devices to avoid pattern collapse. [Background technology]
[0002] In manufacturing methods for ICs having LSI, VLSI, and ULSI, patterned material layers, such as patterned photoresist layers, patterned barrier material layers containing or consisting of titanium nitride, tantalum, or tantalum nitride, patterned multi-stack material layers containing or consisting of stacks of alternating layers of polysilicon and silicon dioxide or silicon nitride, and patterned dielectric material layers containing or consisting of silicon dioxide or dielectric materials with low or ultra-low dielectric constants are manufactured by photolithography techniques. Recently, such patterned material layers include structures with dimensions even smaller than 22 nm, along with high aspect ratios.
[0003] However, regardless of the exposure technique, wet chemical processing of small patterns presents several challenges. As technology advances and dimensional requirements become stricter, patterns are required to include relatively thin and tall structures or device structure features on the substrate, i.e., features with high aspect ratios. These structures can be bent and / or collapse, particularly during the spin-drying process, due to the excessive capillary forces of the deionized water liquid or solution of the rinse fluid that remain between adjacent patterned structures and are positioned between them.
[0004] Traditionally, these problems have been addressed by reducing the maximum stress σ between small features caused by capillary forces, according to Namatsu et al., Appl. Phys. Lett. 66(20), 1995:
number
[0005] Due to dimensional shrinkage, removing particles and plasma etching residues is also a crucial factor in achieving a defect-free patterned structure. This applies not only to photoresist patterns but also to other patterned material layers generated during the manufacture of optical devices, micromachines, and mechanical precision equipment.
[0006] International Publication No. 2012 / 027667 discloses a method for modifying the surface of a high aspect ratio feature by contacting the surface of the high aspect ratio feature with an additive composition to produce a modified surface, wherein the force acting on the high aspect ratio feature when the rinse solution contacts the modified surface is sufficiently minimized to prevent bending or collapse of the high aspect ratio feature, at least during the removal of the rinse solution or at least during the drying of the high aspect ratio feature. Various solvents containing isopropanol but not esters are mentioned. Solvent combinations containing 4-methyl-2-pentanol and tripropylene glycol methyl ether (TPGME) or isopropanol and TPGME are also disclosed.
[0007] An unpublished European patent application, No. 17199807.3, discloses a non-aqueous composition for pattern collapse prevention cleaning comprising a siloxane-based additive. Preferably, the solvent consists essentially of one or more organic solvents, which may be protic or aprotic organic solvents. One or more polar protic organic solvents are preferred, and a single polar protic organic solvent, such as isopropanol, is most preferred.
[0008] U.S. Patent Application No. 2017 / 17008 discloses a patterning composition comprising a polymer and a solvent containing a surface adhesion group for forming a bond with the surface of a patterned feature, as well as a second patterning composition different from the first composition. In addition to many other combinations, the solvent may be a combination of n-butyl acetate and isopropanol.
[0009] JP 2013-257379 discloses a solvent-based rinse composition that uses a combination of a low-fluorine-based, siloxane-based or hydrocarbon-based solvent and another solvent, such as n-butyl acetate.
[0010] However, these compositions still suffer from high pattern collapse in sub-22 nm structures. In particular, without being bound by any theory, the inventors have found that the theoretical correlation by Namatsu is only valid for the same solvent system, and thus the contact angles in the range of about 70° to about 110° measured with deionized water are insufficient to explain the capillary forces of the solvent-based system during drying. Furthermore, Equation (1) only explains the capillary forces during drying and ignores the potential chemical reactions between the collapsing / bending structures during drying and the elastic contraction forces of the collapsed structures. Therefore, the inventors believe that pattern collapse can also be prevented by preventing irreversible adhesion between the collapsed structures.
Prior Art Documents
Patent Documents
[0011]
Patent Document 1
Patent Document 2
Patent Document 3
Patent Document 4
Non-Patent Documents
[0012] [Non-Patent Document 1] Namatsu et al., Appl.Phys.Lett.66(20), 1995 [Overview of the project] [Problems that the invention aims to solve]
[0013] The object of the present invention is to provide a method for manufacturing integrated circuits with nodes of 50 nm or less, particularly nodes of 32 nm or less, and especially nodes of 22 nm or less, without exhibiting the shortcomings of prior art manufacturing methods. [Means for solving the problem]
[0014] In particular, the compounds according to the present invention enable chemical rinsing of patterned material layers containing patterns with a high aspect ratio and line-to-line dimensions of 50 nm or less, especially 32 nm or less, and especially 22 nm or less, without causing pattern collapse.
[0015] Without being constrained by any particular theory, the present invention is based on the finding that approaches that emphasize the low surface tension γ of the fluid and the high contact angle θ of the fluid on the material surface of the feature are ineffective when facing the feature and even shrink. Furthermore, the use of certain additives that affect the surface properties of the patterned substrate does not actually help to avoid pattern collapse of the pattern on the substrate.
[0016] Prior art has focused on surfactants that exhibit a high contact angle in water, and unpublished European Patent Application No. 17199807.3 discloses that the contact angle in water has little to no effect on the ability of surfactants to reduce pattern collapse. However, we have now found that pattern collapse can be further and significantly reduced by appropriately selecting an organic solvent, even without using any surfactants.
[0017] The present invention completely avoids all the drawbacks of the prior art by using a composition comprising an alkanol and a carboxylic acid ester that forms an azeotrope mixture as described herein.
Embodiment for Carrying out the Invention
[0018] One embodiment of the present invention is for treating a substrate containing a pattern having a line width dimension of 50 nm or less and an aspect ratio of 4 or more, a C1-C6 alkanol, and a compound of Formula I
Chemical Formula
[0019] Another embodiment of the present invention is a method for manufacturing an integrated circuit device, an optical device, a micromachine, and a precision mechanical device, comprising (1) preparing a substrate having a patterned material layer having a line width dimension of 50 nm or less, an aspect ratio of 4 or more, or a combination thereof; (2) contacting the substrate with the composition defined herein at least once; and (3) removing the composition from the contact with the substrate and the method comprises.
[0020] The use of these two types of organic solvents is particularly useful for patterned developable photoresist layers containing patterns with line-to-line dimensions of 50 nm or less, especially 32 nm or less, and most specifically 22 nm or less.
[0021] Furthermore, the use of these two types of organic solvents in the present invention is particularly useful for aspect ratios of 4 or higher without causing pattern collapse.
[0022] It should be noted that the compositions of the present invention are generally useful in avoiding pattern collapse of photoresist structures and pattern collapse of non-photoresist patterns having high aspect ratio stacks (HARS).
[0023] The present invention relates to compositions particularly suitable for manufacturing patterned materials containing sub-50 nm size features, such as integrated circuit (IC) devices, optical devices, micromachines, and mechanical precision devices, and especially IC devices.
[0024] Any conventional and known substrate used for manufacturing IC devices, optical devices, micromachines and mechanical precision devices can be used in the method of the present invention. Preferably, the substrate is a semiconductor substrate, more preferably a silicon wafer, which is conventionally used for manufacturing IC devices, particularly IC devices including ICs having LSIs, VLSIs and ULSIs.
[0025] The composition is particularly suitable for processing substrates having a patterned material layer with inter-line dimensions of 50 nm or less, especially 32 nm or less, and especially 22 nm or less, i.e., a patterned material layer of the sub-22 nm technology node. The patterned material layer preferably has an aspect ratio greater than 4, preferably greater than 5, more preferably greater than 6, even more preferably greater than 8, even more preferably greater than 10, even more preferably greater than 12, even more preferably greater than 15, and even more preferably greater than 20. The smaller the inter-line dimensions and the higher the aspect ratio, the more advantageous the use of the composition described herein becomes. The critical aspect ratio also depends on the substrate on which the pattern collapse prevention treatment is performed. For example, an aspect ratio of 4 is already difficult for dielectrics with low dielectric constants, as they are more unstable and tend to collapse.
[0026] As long as the structure is prone to collapse due to its shape, the composition of the present invention can be applied to any patterned material substrate.
[0027] For example, a patterned material layer is, (a) A patterned silicon layer, or a Si layer coated with silicon oxide or silicon nitride, (b) A patterned barrier material layer containing or consisting of ruthenium, cobalt, titanium nitride, tantalum, or tantalum nitride, (c) A patterned multi-stack material layer comprising or consisting of layers of at least two different materials selected from the group consisting of silicon, polysilicon, silicon dioxide, low dielectric constant and ultra-low dielectric constant materials, high dielectric constant materials, semiconductors other than silicon and polysilicon, and metals. (d) A patterned dielectric material layer containing or consisting of silicon dioxide or a dielectric material with a low dielectric constant or ultra-low dielectric constant. It is possible.
[0028] The composition contains two types of organic solvents: C1-C6 alkanols and carboxylic acid esters.
[0029] Alkanol The first organic solvent in the composition is a linear or branched C1-C6 alkanol (also referred to as "alkanol").
[0030] Preferably, the alkanol is a C1-C5 alkanol, more preferably a C1-C4 alkanol, most preferably methanol, ethanol, 1-propanol, or 2-propanol. 2-propanol is particularly preferred.
[0031] ester The second organic solvent in the composition is of formula I [ka] (In the formula, R 1 This includes unsubstituted or linear or branched C1-C6 alkyl groups which may be substituted with OH or F, and -X 21 -[OX 22 ] n - Selected from H, R 2 This includes unsubstituted or linear or branched C1-C6 alkyl groups which may be substituted with OH or F, and -X 21 -[OX 22 ] n - Selected from H, X 21 , X 22 These are independently selected from straight-chain or branched C1-C6 alkanediyl molecules that may be unsubstituted or substituted with OH or F. n is an integer between 1 and 5. It is a carboxylic acid ester (also called an "ester") of [the substance].
[0032] In a first preferred embodiment, R 1 The alkyl group is selected from linear or branched C1-C5 alkyl groups, more preferably C1-C4 alkyl groups, most preferably methyl, ethyl, 1-propyl, or 2-propyl groups. Such alkyl groups may be unsubstituted or substituted with OH or F. 2The alkyl group is selected from linear or branched C1-C5 alkyl groups, more preferably C1-C4 alkyl groups, most preferably methyl, ethyl, 1-propyl, or 2-propyl groups. Such alkyl groups may be unsubstituted or substituted with OH or F groups.
[0033] In a second preferred embodiment, R 1 The alkyl group is selected from linear or branched C1-C5 alkyl groups, more preferably C1-C4 alkyl groups, most preferably methyl, ethyl, 1-propyl, or 2-propyl groups. Such alkyl groups may be unsubstituted or substituted with OH or F. 2 is, -X 21 -[OX 22 ] n -H and X 21 , X 22 These are independently selected from linear or branched C1-C6 alkanediyl, preferably C1-C5 alkanediyl, more preferably C1-C4 alkanediyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl, or propane-1,2-diyl, and are integers from 1 to 5, preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, and most preferably 1. Such alkanediyl may be unsubstituted or substituted with OH or F.
[0034] In a third preferred embodiment, R 1 is, -X 21 -[OX 22 ] n -H and X 21 , X 22 These are independently selected from linear or branched C1-C6 alkanediyl, preferably C1-C5 alkanediyl, more preferably C1-C4 alkanediyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl, or propane-1,2-diyl, and are integers from 1 to 5, preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, most preferably 1. Such alkanediyl may be unsubstituted or substituted with OH or F. 2The alkyl group is selected from linear or branched C1-C5 alkyl groups, more preferably C1-C4 alkyl groups, most preferably methyl, ethyl, 1-propyl, or 2-propyl groups.
[0035] In a fourth preferred embodiment, R 1 is, -X 21 -[OX 22 ] n -H and X 21 , X 22 These are independently selected from linear or branched C1-C6 alkanediyl, preferably C1-C5 alkanediyl, more preferably C1-C4 alkanediyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl, or propane-1,2-diyl, and are integers from 1 to 5, preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, most preferably 1. Such alkanediyl may be unsubstituted or substituted with OH or F. 2 is, -X 21 -[OX 22 ] n -H and X 21 , X 22 These are independently selected from linear or branched C1-C6 alkanediyl, preferably C1-C5 alkanediyl, more preferably C1-C4 alkanediyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl, or propane-1,2-diyl, and are integers from 1 to 5, preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, and most preferably 1. Such alkanediyl may be unsubstituted or substituted with OH or F.
[0036] Particularly preferred esters are ethyl acetate, methyl acetate, isopropyl acetate, and those also known as 1-methoxy-2-propyl acetate, propylene glycol monomethyl ether acetate, or PGMEA.
[0037] composition The alkanol and ester must be capable of forming an azeotropic mixture, preferably an azeotropic mixture exhibiting the lowest temperature. Generally, the content of the alkanol in the solvent mixture of the alkanol and ester is preferably between 20% by mass and 20% by mass of the azeotropic mixture.
[0038] In a preferred embodiment, the content of alkanol in the solvent mixture of alkanol and ester is preferably less than 15% by mass to more than 15% by mass of the azeotropic mixture. More preferably, the content of alkanol in the solvent mixture of alkanol and ester is less than 10% by mass to more than 10% by mass of the azeotropic mixture. Even more preferably, the content of alkanol in the solvent mixture of alkanol and ester is less than 8% by mass to more than 8% by mass of the azeotropic mixture. Most preferably, the content of alkanol in the solvent mixture of alkanol and ester is less than 5% by mass to more than 5% by mass of the azeotropic mixture.
[0039] In a particularly preferred embodiment, the pattern collapse prevention cleaning (APCC) composition essentially consists of organic solvents, which in particular essentially consist of alkanols and carboxylic acid esters.
[0040] In another embodiment, the composition is a homogeneous (one-phase) composition.
[0041] When a combination of 2-propanol and ethyl acetate is used, 2-propanol is preferably present in an amount of 15 to 35% by mass, and particularly preferably 20 to 30% by mass.
[0042] Preferably, the composition is non-aqueous. As used herein, “non-aqueous” means that the composition may contain only a small amount of water, up to about 1% by mass. Preferably, the non-aqueous composition contains less than 0.5% by mass, more preferably less than 0.2% by mass, even more preferably less than 0.1% by mass, even more preferably less than 0.05% by mass, even more preferably less than 0.02% by mass, even more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass. Most preferably, water is essentially absent from the composition. Here, “essentially” means that the water present in the composition does not significantly affect the performance of the additive in the non-aqueous composition with respect to pattern collapse of the substrate being treated.
[0043] Furthermore, compared to the use of a single organic solvent and the siloxane-based additive described in European Patent Application No. 17199807.3, the compositions of the present invention have been found to be remarkably tolerable in terms of their water content. Thus, the compositions can contain up to 10% by volume of water, and pre-drying of the solvent can be avoided. Preferably, the water content can be 0.5 to 5% by mass.
[0044] The solvent mixture must have a boiling point low enough to be removed by heating without adversely affecting the substrate being treated with the composition. For a typical substrate, the boiling point of the organic solvent must be 150°C or lower, preferably 100°C or lower.
[0045] In addition to the two organic solvents, other organic solvents may be present in an amount of up to 10% by mass.
[0046] Further additives, such as surfactants, may be present in the composition in amounts that support the composition's pattern collapse prevention properties. Such surfactants may be, but are not limited to, those of formulas I-IV of the unpublished European Patent Application No. 17199807.3, which is more clearly incorporated by reference herein.
[0047] The content of other compounds must preferably be less than 1% by mass, more preferably less than 0.5% by mass, even more preferably less than 0.1% by mass, and most preferably less than 0.01% by mass. It is particularly preferable that the composition consists essentially of the two organic solvents present in the composition of the present invention. As used herein, "consistently of" means that the content of other components does not affect the pattern collapse prevention properties of the composition.
[0048] According to the method of the present invention, compositions comprising alkanols and esters can be used for different purposes and objectives. Accordingly, the compositions can be used as impregnation solutions for impregnating photoresists during chemical light irradiation through a mask, as developers for photoresist layers exposed to chemical light through a mask, and as chemical rinse compositions for rinsing patterned material layers.
[0049] In one embodiment, a method for manufacturing an integrated circuit device, an optical device, a micromachine, and a precision mechanical device, (1) A step of preparing a substrate having a patterned material layer with line spacing of 50 nm or less and an aspect ratio of 4 or more, (2) A step of bringing a substrate into contact with a composition comprising the alkanol and ester described herein at least once, (3) A step of removing the composition from contact with the substrate. Methods including the following were found.
[0050] In the third step of the method of the present invention, the composition is removed from contact with the substrate. Any known method conventionally used to remove a liquid from a solid surface may be used.
[0051] Preferably, the substrate is (i) A step of preparing a substrate having an impregnation photoresist, EUV photoresist, or eBeam photoresist layer, (ii) A step of exposing the photoresist layer to a chemical beam through a mask with or without impregnation solution, (iii) A step of developing the exposed photoresist layer with a developer to obtain a pattern having a line-to-line dimension of 32 nm or less and an aspect ratio of 4 or more, (iv) A step of applying the composition described herein to a patterned develop photoresist layer, (v) A step of spin-drying the semiconductor substrate after coating with the composition. It is prepared using photolithography, including the following methods.
[0052] Any conventional and known impregnation photoresist, EUV photoresist, or eBeam photoresist may be used. The impregnation photoresist may already contain at least one or a combination thereof of siloxane additives. Furthermore, the impregnation photoresist may contain other nonionic additives. Suitable nonionic additives are described, for example, in U.S. Patent Application Publication 2008 / 0299487, page 6, paragraph
[0078] . Most preferably, the impregnation photoresist is a positive resist.
[0053] In addition to eBeam exposure or extreme ultraviolet light at approximately 13.5 nm, ultraviolet light with a wavelength of 193 nm is preferably used as a chemical beam.
[0054] In the case of impregnation lithography, ultrapure water is preferably used as the impregnation solution.
[0055] Any conventional and known developer can be used to develop the exposed photoresist layer. Preferably, an aqueous developer containing tetramethylammonium hydroxide (TMAH) is used.
[0056] Preferably, the chemical rinse composition is applied to the photoresist layer that has been exposed and developed as a paddle.
[0057] The inclusion of a combination of alcohol and ester in the chemical rinse composition is essential for the photolithography method according to the present invention.
[0058] Conventional and well-known apparatus commonly used in the semiconductor industry can be used to perform photolithography according to the method of the present invention. [Examples]
[0059] The pattern collapse performance of formulations during drying was determined using patterned silicon wafers with circular nanopillar patterns. The AR20 pillars (aspect ratio) used in the test had a height of 600 nm and a diameter of 30 nm. The pitch size was 90 nm. 1 × 1 cm wafer pieces were processed in the following order without intermediate drying: • Immerse in 0.9% dilute hydrofluoric acid (DHF) for 50 seconds. • Immerse in ultrapure water (UPW) for 60 seconds. • Immerse in 2-propanol (isopropanol, IPA) for 30 seconds. • Immerse in a composition consisting of the amounts of 2-propanol and ethyl acetate specified in Table 1 for 60 seconds at room temperature. • Immerse in IPA for 60 seconds. • N2 blow dry.
[0060] Dry silicon wafers were analyzed using a top-down SEM. Examples of collapse statistics are shown in Tables 1-4. Because collapse varied from the center to the edge, only structures obtained from essentially the same center-edge distance were compared.
[0061] The cluster size distribution of pattern collapse was determined from SEM images. Cluster size corresponds to the number of uncollapsed pillars that make up each cluster. For example, if a wafer before processing contains 4x4 pillars and 8 pillars are still uncollapsed, 4 pillars will collapse into 2 clusters containing 2 pillars each, and 4 pillars will collapse into 1 cluster containing 4 pillars. The ratio is 8 / 11 single clusters, 2 / 11 double clusters, and 1 / 11 clusters of 4 pillars. The more single (1) clusters there are, the better the performance of the pattern collapse prevention treatment. The more clusters of 3, 4, or even >5, the worse the effect of the treatment.
[0062] [Table 1]
[0063] Table 1 shows that compositions 3 to 6 exhibit beneficial effects on the degree of pattern collapse compared to compositions containing only 2-propanol. In particular, compositions close to azeotropic mixtures containing 20-30% by mass of 2-propanol and 70-80% by mass of ethyl acetate show virtually no collapse at all.
[0064] [Table 2]
[0065] The results of Experiments 7-8, shown in Table 2, demonstrate that the claimed solvent combination is dramatically more effective in preventing pattern collapse compared to a single solvent.
[0066] [Table 3]
[0067] The results of experiments 10-12, shown in Table 3, indicate that large amounts of 2-propanol, compared to the claimed amount, do not have a positive effect on preventing pattern collapse.
[0068] [Table 4]
[0069] The results of experiments 13–17, shown in Table 4, are surprisingly, and in contrast to the use of a single solvent combined with an additive, such as a siloxane-based surfactant described in the unpublished European Patent Application No. 17199807.3, that solvent mixtures are highly tolerant of their water content. Even with 10% water, the effect on the pattern collapse prevention performance of the composition is minimal. Thorough drying of the solvent can thus be omitted.
Claims
1. A method for rinsing a substrate having a pattern having line-to-line dimensions in the range of 22 nm to 60 nm and an aspect ratio in the range of 4 to 20, using a composition comprising 2-propanol and ethyl acetate, The composition contains 2-propanol in an amount of 15 to 35% by mass, and ethyl acetate in an amount of 65 to 85% by mass, and A method wherein the composition comprises only 2-propanol and ethyl acetate.
2. A method for manufacturing an apparatus including a substrate having a pattern having line-to-line dimensions in the range of 22 nm to 60 nm and an aspect ratio in the range of 4 to 20, (1) A step of preparing a substrate having a patterned material layer having line spacing in the range of 22 nm to 60 nm and an aspect ratio in the range of 4 to 20, (2) A step of processing the substrate by bringing the substrate into contact with the rinse composition at least once, (3) A step of removing the rinse composition from contact with the substrate. The rinse composition contains 2-propanol in an amount of 15 to 35% by mass, and ethyl acetate in an amount of 65 to 85% by mass, and The rinse composition comprises only 2-propanol and ethyl acetate, and The method wherein the apparatus is at least one selected from the group consisting of integrated circuit apparatus, optical apparatus, micromachine, and mechanical precision apparatus.
3. The method according to claim 2, wherein the patterned material layer has line-to-line dimensions in the range of 22 nm to 32 nm.
4. The method according to claim 2 or 3, wherein the patterned material layer is selected from the group consisting of a patterned developable photoresist layer, a patterned barrier material layer, a patterned multi-stack material layer, and a patterned dielectric material layer.
5. A substrate having a patterned material layer having line spacing in the range of 22 nm to 60 nm and aspect ratio in the range of 4 to 20, (i) A step of preparing a substrate having an impregnated photoresist, EUV photoresist, or eBeam photoresist layer, (ii) A step of exposing the photoresist layer to a chemical beam through a mask, with or without impregnation solution, (iii) A step of developing the exposed photoresist layer with a developer to obtain a pattern having line spacing in the range of 22 nm to 60 nm and an aspect ratio in the range of 4 to 20, The method according to any one of claims 2 to 4, which includes being prepared by photolithography.