Filling film forming material for preventing collapse of semiconductor substrate pattern and semiconductor substrate processing method

Abstract

To provide a material for forming a filling film for inhibiting semiconductor substrate pattern collapse realizing a filling film capable of filling a fine structure pattern having a high aspect ratio without causing voids, and a method for treating a semiconductor substrate capable of inhibiting semiconductor substrate pattern collapse.SOLUTION: A material for forming a filling film for inhibiting semiconductor substrate pattern collapse contains: (A) a polymer having a structural unit shown by the general formula (1) in the figure; (B) a residual-solvent removal promoter with a specific structure; and (C) an organic solvent. The ratio Mw / Mn of the polymer (A) satisfies 2.50≤Mw / Mn≤9.00. The content of the residual-solvent removal promoter (B) is 0.1 to 40 pts.mass based on 100 pts.mass of the polymer (A).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filling film forming material for suppressing collapse of semiconductor substrate patterns and a method for treating semiconductor substrates. [Background technology]

[0002] In manufacturing processes for semiconductor devices, microelectromechanical systems (MEMS), and the like, substrates (processing objects) are processed with liquid. For example, substrates, laminated films, resist films, and the like are patterned by liquid processing, and microstructures are formed on the substrates. Furthermore, impurities, residues, and the like remaining on the substrates are removed by cleaning with liquid. Furthermore, these processes are often performed in combination. Then, when the liquid is removed after the liquid processing, the microstructures formed on the substrates may collapse due to the surface tension of the liquid.

[0003] Meanwhile, semiconductor devices for networks and digital home appliances are becoming increasingly smaller, more highly integrated, and faster, leading to increasingly finer substrate patterns. As the aspect ratio (the ratio of height to width) increases with the miniaturization of substrate patterns, this can lead to problems such as pattern collapse when the gas-liquid interface passes through the pattern during wafer drying after cleaning or rinsing. Examples of fine structure patterns prone to pattern collapse include line-and-space patterns in logic FinFet structures, line-and-space and island patterns in shallow trench isolation (STI) structures in dynamic random access memory (DRAM), pillar patterns in DRAM capacitor structures, and hole and slit patterns in 3D-NAND cell structures. Since no effective countermeasures for this inconvenience have been found, in order to reduce the size, increase the integration density, or increase the speed of semiconductor devices and micromachines, it is necessary to design patterns that do not collapse, which significantly restricts the freedom of pattern design.

[0004] Patent Document 1 discloses a technique for suppressing collapse of substrate patterns by replacing water with 2-propanol as a cleaning solution before the gas-liquid interface passes through the pattern. However, it is said that there are limitations, such as the aspect ratio of the pattern that can be handled being 5 or less.

[0005] Patent Document 2 discloses a cleaning method in which a wafer surface having a concave-convex pattern formed thereon using a silicon-containing film is modified by oxidation or the like, and a water-repellent protective film is formed on this surface using a water-soluble surfactant or a silane coupling agent, thereby reducing capillary force and preventing the pattern from collapsing.

[0006] Patent Document 3 discloses a technique for preventing collapse of a substrate pattern by carrying out a hydrophobic treatment using a treatment liquid containing a silylating agent such as N,N-dimethylaminotrimethylsilane and a solvent.

[0007] Patent Document 4 proposes a method in which a substrate on which a concave-convex pattern has been formed is washed with a rinse solution, and then the rinse solution remaining in the recesses of the pattern is replaced with a filling treatment solution containing a sublimable substance such as camphor or naphthalene, which is then filled into the recesses of the pattern, the sublimable substance is precipitated from the treatment solution, and the precipitated solid sublimable substance is removed by sublimation. However, it is disclosed that a method using a general sublimable substance frequently fails to fill the recesses of the pattern with the sublimable substance, and therefore is not effective in suppressing pattern collapse on the substrate surface.

[0008] Patent Document 5 discloses a technique for preventing collapse of a substrate pattern by forming a filling film on the pattern side of a substrate having a pattern formed on one side thereof, the filling film being formed by coating the pattern side with a treatment agent for inhibiting collapse of a substrate pattern, the treatment agent containing a compound having an aromatic ring and a solvent. Patent Document 6 discloses a technique for preventing collapse of a substrate pattern by forming a filling film by coating a treatment agent for inhibiting collapse of a substrate pattern, the treatment agent containing a hydroxyl group-containing vinyl polymer and a solvent. The filling film requires heat treatment to prevent thermal melting of the filling film when removed by dry etching or the like, thereby maintaining the strength of the substrate pattern. However, a composition consisting only of a compound having many hydrophilic groups and a solvent makes it difficult for the residual solvent in the compound to be released from the filling film at the bottom of the pattern during heat treatment, and instead foams and forms voids in the filling film, resulting in an insufficient effect of inhibiting collapse of a high aspect ratio microstructure pattern.

[0009] Patent Document 7 discloses a resist underlayer film-forming composition for a multilayer resist process, characterized by containing a specific polymer, a specific crosslinking agent, an acid generator, and a solvent. While the composition is capable of forming a thick film with excellent storage stability and crack resistance, the combination of the specific polymer and the specific crosslinking agent provides insufficient filling of high-aspect-ratio patterned substrates. For these reasons, there is a demand for a filling film-forming material for suppressing pattern collapse that has excellent filling properties for high-aspect-ratio microstructure patterns. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-198958 [Patent Document 2] Patent No. 4403202 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-129932 [Patent Document 4] Japanese Patent Application Laid-Open No. 2013-042093 [Patent Document 5] International Publication No. 2018 / 074535 [Patent Document 6] Patent No. 6718123 [Patent Document 7] Patent No. 6550760 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made based on the above circumstances, and aims to provide a filling film forming material for suppressing collapse of semiconductor substrate patterns, which provides a filling film that can fill high aspect ratio microstructure patterns without voids, and a semiconductor substrate processing method that can suppress collapse of semiconductor substrate patterns. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the present invention provides a filling film-forming material for suppressing collapse of a semiconductor substrate pattern, the filling film-forming material comprising: (A) a polymer having a structural unit represented by the following general formula (1); (B) a residual solvent removal promoter containing a compound represented by the following general formula (2); and (C) an organic solvent, wherein the ratio Mw / Mn of the weight average molecular weight Mw of the polymer (A) relative to the number average molecular weight Mn in terms of polystyrene, as determined by gel permeation chromatography, is 2.50≦Mw / Mn≦9.00; the content of the (B) residual solvent removal promoter is 0.1 to 40 parts by mass per 100 parts by mass of the polymer (A); and the filling film-forming material for suppressing collapse of a semiconductor substrate pattern is free of an acid generator. [ka] (In the general formula (1), R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1. [ka] (In the general formula (2), Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 02 is a hydrogen atom or a methyl group, and q is an integer of 1 to 5.

[0013] With such a filler film-forming material for suppressing collapse of semiconductor substrate patterns, during heat treatment of the filler film after filling a high-aspect ratio pattern substrate, the elimination of residual solvent contained in the (A) polymer in the filler film is promoted by the (B) residual solvent elimination promoter, enabling the formation of a filler film free of voids, thereby providing a processing method with excellent suppression of substrate pattern collapse after removal of the filler film. Furthermore, a filler film-forming material for suppressing collapse of semiconductor substrate patterns containing the (A) polymer within such a molecular weight dispersity range has high fluidity, making it effective for filling high-aspect ratio pattern substrates. It also has excellent film-forming properties and can suppress the generation of sublimates during heat treatment, thereby preventing equipment contamination by sublimates. It is also effective in reducing coating defects and residue after removal of the filler film, making it an excellent filler film-forming material for suppressing collapse of semiconductor substrate patterns. Furthermore, when the filling film that has filled the substrate pattern is heat-treated, the crosslinking reaction between the (A) polymer and the (B) residual solvent removal promoter proceeds gently, and the removal of the residual solvent contained in the (A) polymer in the filling film is promoted by the (B) residual solvent removal promoter, making it possible to form a filling film that does not contain voids.

[0014] In the present invention, the polymer (A) preferably has a structural unit represented by the following general formula (3) in addition to the structural unit represented by the general formula (1). [ka] (In the general formula (3), R 03 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, p is 0 or 1, and R 01 and X are the same as above.)

[0015] A filling film forming material for suppressing collapse of semiconductor substrate patterns containing a polymer such as that represented by the general formula (3) has increased fluidity and is effective for filling substrates with patterns of higher aspect ratios. Furthermore, because of its low affinity with polar solvents, it is effective for reducing the amount of residual solvent in the filling film.

[0016] In the present invention, in the general formula (3), R03 is preferably either an alkyl group having 1 to 30 carbon atoms or a structure represented by the following general formula (4). [ka] (In the above general formula (4), * represents a bonding site to an oxygen atom, and R A represents an optionally substituted divalent organic group having 1 to 10 carbon atoms, R B is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms.

[0017] A filler film-forming material for suppressing collapse of semiconductor substrate patterns containing such a polymer (A) has increased fluidity, making it even more effective for filling high aspect ratio patterned substrates, and its low affinity with polar solvents makes it effective for reducing the amount of residual solvent in the filler film. Furthermore, its increased crosslinking reactivity provides excellent film-forming properties and solvent resistance, and it can suppress the generation of sublimates during heat treatment and prevent equipment contamination by sublimates. It is effective in reducing coating defects and residues after removal of the filler film, making it an even more excellent filler film-forming material for suppressing collapse of semiconductor substrate patterns.

[0018] In the present invention, the content of the general formula (3) preferably satisfies the relationship a+b=100, b≦90, where a is the proportion of the general formula (1) and b is the proportion of the general formula (3).

[0019] The filling film forming material for suppressing collapse of semiconductor substrate patterns containing the polymer (A) can suppress deterioration of adhesion between the filling film and the substrate pattern, and reduce the occurrence of cracks in the filling film. Furthermore, since the affinity increases when replacing the cleaning solution retained in the recesses, the material is effective for filling substrates with high aspect ratio patterns.

[0020] In the present invention, the (C) organic solvent preferably contains a high-boiling point solvent.

[0021] Such organic solvents (C) are preferable in practice because they allow fine adjustment of properties such as film-forming properties and filling properties in accordance with customer requirements.

[0022] In the present invention, the high boiling point solvent is preferably one or more organic solvents having a boiling point of 180° C. or higher.

[0023] Such a filling film forming material for suppressing collapse of semiconductor substrate patterns has increased fluidity, making it even more effective for filling substrates with high aspect ratio patterns.

[0024] In the present invention, it is preferable that the filling film forming material for suppressing collapse of a semiconductor substrate pattern further contains (D) a surfactant.

[0025] Such a filling film forming material for suppressing collapse of semiconductor substrate patterns is preferable in practice because it allows fine adjustment of performance such as film forming properties and filling properties in accordance with customer requirements.

[0026] In the present invention, the amount of metal impurities in the material for forming a filling film for suppressing collapse of a semiconductor substrate pattern is preferably 3 ppb or less in terms of mass ratio.

[0027] In the present invention, the metal is preferably Na, Mg, K, Ca, Mn, Fe, Ni, Cu, or Ti.

[0028] In this way, by using the above-described material for forming a filling film for suppressing collapse of a semiconductor substrate pattern, it is possible to reduce the amount of metal impurities on the substrate surface after removing the filling film from the substrate pattern.

[0029] The present invention also provides a method for processing a semiconductor substrate, comprising the steps of filling a semiconductor substrate having an aspect ratio of 5 or more and a concave-convex pattern formed on its surface with the above-mentioned filling film forming material for suppressing collapse of a semiconductor substrate pattern, to form a filling film, and removing the filling film.

[0030] In this way, the filling film forming material for suppressing collapse of a substrate pattern of the present invention can be suitably used as a filling film for a substrate having an aspect ratio of 5 or more and having an uneven pattern formed on its surface, and since it has excellent properties for suppressing collapse of the substrate pattern after removal of the filling film, it can be suitably used in a substrate pattern collapse suppression process for suppressing collapse or destruction that occurs when drying a cleaning solution or rinse solution after cleaning the substrate pattern.

[0031] The present invention also provides a method for performing a drying process on a semiconductor substrate having a concave-convex pattern formed on its surface, the method comprising the steps of: (1) a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid, or a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid and then replacing the cleaning liquid with a rinse liquid; (2) replacing the cleaning solution or rinsing solution with the above-described filling film-forming material for suppressing collapse of a semiconductor substrate pattern, and filling the filling film; (3) a step of hardening the filling film by heat treatment at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds; (4) removing the hardened filler film from the semiconductor substrate by dry etching; and drying the semiconductor substrate by the step of:

[0032] As such, the filling film forming material for suppressing collapse of semiconductor substrate patterns of the present invention can be suitably used as a filling film for substrates having a concave-convex pattern formed on the surface, and is excellent in suppressing collapse of the substrate pattern after the filling film is removed, making it suitable for a process for suppressing collapse of semiconductor substrate patterns, which suppresses collapse or destruction that occurs when drying a cleaning solution or rinse solution after cleaning the substrate pattern.

[0033] Further, the present invention provides a method for drying a semiconductor substrate having a concave-convex pattern formed on a surface thereof, and performing a process for forming a concave-convex pattern different from the concave-convex pattern on the semiconductor substrate, the method comprising the steps of: (1) a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid, or a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid and then replacing the cleaning liquid with a rinse liquid; (2) replacing the cleaning solution or rinsing solution with the above-described filling film-forming material for suppressing collapse of a semiconductor substrate pattern, and filling the filling film; (3) a step of hardening the filling film by heat treatment at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds; (4) forming a silicon-containing resist intermediate film on the cured filling film using a silicon-containing resist intermediate film material; (5) forming a resist upper layer film on the silicon-containing resist intermediate film using a photoresist composition; (6) forming a circuit pattern on the resist upper layer film; (7) a step of transferring the pattern to the silicon-containing resist intermediate film by etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (8) A step of transferring a pattern to the hardened filling film by etching using the silicon-containing resist intermediate film to which the pattern has been transferred as a mask; (9) forming a recessed and raised pattern different from the recessed and raised pattern by etching the semiconductor substrate having the recessed and raised pattern formed on its surface using the hardened filling film to which the pattern has been transferred as a mask; (10) removing the hardened filler film from the semiconductor substrate by dry etching; The present invention provides a method for processing a semiconductor substrate, comprising:

[0034] As such, the filler film-forming material for suppressing semiconductor substrate pattern collapse of the present invention can be used to fill a substrate having a textured pattern formed on its surface and is also suitable for use as a resist underlayer film for a multilayer resist process, making it possible to omit the steps of removing the applied filler film after substrate cleaning and applying a resist underlayer film for a multilayer resist process, thereby contributing to the rationalization of the semiconductor manufacturing process.Alternatively, by replacing a drying step that does not use the filler film-forming material for suppressing semiconductor substrate pattern collapse, such as a drying method using 2-propanol, with the filler film-forming material for suppressing semiconductor substrate pattern collapse of the present invention, it is possible to omit the application step of applying a resist underlayer film for a multilayer resist process, thereby contributing to the rationalization of the semiconductor process.

[0035] In the present invention, the metal impurities on the surface of the semiconductor substrate after removing the hardened filling film from the semiconductor substrate are 2.0×10E +10 atoms / cm 2 It is preferable to do the following:

[0036] As described above, the filler film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention contains a small amount of metal impurities, and therefore the amount of metal impurities on the substrate surface after removing the filler film from the substrate pattern is also small. Therefore, there is little risk of a decrease in device yield and reliability, and the material is suitable for a process for suppressing collapse of semiconductor substrate patterns, which suppresses collapse and breakdown that occur when the cleaning solution after cleaning the substrate pattern is dried.

[0037] In the present invention, the cleaning liquid or rinsing liquid preferably contains at least one of water, a water-soluble alcohol, and a fluorine compound.

[0038] By selecting such a cleaning liquid or rinse liquid, high affinity with the material for forming a filling film for suppressing collapse of a semiconductor substrate pattern can be ensured, and substitution can be carried out efficiently. [Effects of the Invention]

[0039] As described above, the filler film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention and the semiconductor substrate processing method using the material have high filling properties for patterned substrates with high aspect ratios, and therefore are excellent in suppressing collapse of substrate patterns after filler film removal. For example, they can be widely applied to fine structure patterns prone to substrate pattern collapse, such as line-and-space patterns in logic FinFet structures, line-and-space patterns or island patterns in DRAM STI structures, pillar patterns in DRAM capacitor structures, and hole and slit patterns in 3D-NAND cell structures. Furthermore, since the amount of metal impurities on the semiconductor substrate surface after filler film removal is low, they are extremely useful in substrate cleaning and drying processes. Therefore, the filler film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention and the semiconductor substrate processing method using the material can be suitably used in semiconductor substrate pattern collapse suppression processes for suppressing collapse or destruction that occurs when drying cleaning or rinsing solutions after cleaning substrate patterns, which are expected to become more widely used as substrate patterns become higher in aspect ratio due to further semiconductor miniaturization in the future. [Brief explanation of the drawings]

[0040] [Figure 1] 1A and 1B are explanatory views of an example of a method for treating a semiconductor substrate using a filling film-forming material for suppressing collapse of a semiconductor substrate pattern according to the present invention. [Figure 2] 10A and 10B are explanatory diagrams illustrating another example of a method for treating a semiconductor substrate pattern using the filling film-forming material for suppressing collapse of a semiconductor substrate pattern of the present invention. [Figure 3] 10A and 10B are explanatory diagrams of an example of a semiconductor substrate pattern collapse suppression problem that causes collapse of a substrate pattern compared in an embodiment of the present invention. [Figure 4] FIG. 2 is an explanatory diagram of a flatness evaluation method in an example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] As described above, with the miniaturization of semiconductor devices, there has been a demand for a filling film-forming material for suppressing collapse of semiconductor substrate patterns, which has high filling properties for high aspect ratio pattern substrates and is excellent in suppressing collapse of substrate patterns after removal of the filling film, in a process for suppressing collapse of high aspect ratio pattern substrates after substrate cleaning, and a method for treating semiconductor substrates using this material.

[0042] As a result of extensive research into the above-mentioned problems, the inventors have verified the effect of forming a filling film in suppressing the collapse of substrate patterns in a process for suppressing the collapse of high aspect ratio pattern substrates after substrate cleaning, and have found that a filling film-forming material for suppressing the collapse of semiconductor substrate patterns, which is composed mainly of a polymer with a specific structure and a residual solvent removal promoter, and a method for treating semiconductor substrates using said material, are extremely effective in eliminating voids in the filling film that cause substrate pattern collapse, and have thus completed the present invention.

[0043] That is, the present invention provides a filling film-forming material for suppressing collapse of a semiconductor substrate pattern, the filling film-forming material comprising: (A) a polymer having a structural unit represented by the following general formula (1); (B) a residual solvent removal promoter containing a compound represented by the following general formula (2); and (C) an organic solvent, wherein the ratio Mw / Mn of the weight average molecular weight Mw of the polymer (A) relative to the polystyrene equivalent weight average molecular weight Mn as determined by gel permeation chromatography is 2.50≦Mw / Mn≦9.00; the content of the (B) residual solvent removal promoter is 0.1 to 40 parts by mass per 100 parts by mass of the polymer (A); and the filling film-forming material for suppressing collapse of a semiconductor substrate pattern does not contain an acid generator. [ka] (In the general formula (1), R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1. [ka] (In the general formula (2), Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 02 is a hydrogen atom or a methyl group, and q is an integer of 1 to 5.

[0044] While the present invention will be described below with reference to exemplary embodiments, it should be understood that the present invention is not limited to the following exemplary embodiments. In other words, it should be understood that modifications and improvements to the following exemplary embodiments, as appropriate, based on the ordinary knowledge of those skilled in the art, also fall within the scope of the present invention.

[0045] <Filling film forming material for preventing semiconductor substrate pattern collapse> The filler film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention comprises (A) a polymer having a structural unit represented by the general formula (1), (B) a residual solvent removal promoter containing a compound represented by the general formula (2), and (C) an organic solvent, wherein the ratio Mw / Mn of the weight average molecular weight Mw of the polymer (A) relative to the number average molecular weight Mn as measured by gel permeation chromatography (GPC) is 2.50≦Mw / Mn≦9.00, the content of the (B) residual solvent removal promoter is 0.1 to 40 parts by mass per 100 parts by mass of the (A) polymer, and the material does not contain an acid generator. This filler film-forming material for suppressing collapse of semiconductor substrate patterns is suitable for use in a processing method that, after a cleaning step for a semiconductor substrate having a concave-convex pattern formed on its surface and before a drying step, displaces the cleaning solution or rinse solution retained in the recesses to fill the recesses, and then removes the formed filler film by dry etching.

[0046] The filler film-forming material for suppressing collapse of semiconductor substrate patterns is preferably used to fill gaps in a substrate pattern. Specifically, after cleaning a substrate having a concave-convex pattern formed on its surface, the filler film-forming material for suppressing collapse of semiconductor substrate patterns is applied to the surface of the substrate facing the concave-convex pattern. As a result, liquids such as cleaning solutions and rinse solutions on the substrate are replaced with the filler film-forming material for suppressing collapse of semiconductor substrate patterns, forming a film (filler film) that fills the gaps in the concave pattern. This method allows the liquids such as cleaning solutions and rinse solutions to be removed without drying them, thereby suppressing pattern collapse due to the passage of an air-liquid interface along the side of the substrate pattern. This filler film can be removed from the substrate as needed by dry etching or the like.

[0047] The filling film-forming material for suppressing collapse of semiconductor substrate patterns contains (A) a polymer, (B) a residual solvent removal promoter, and (C) a solvent, and does not contain an acid generator, thereby making it possible to form a filling film that is excellent in suppressing collapse of substrate patterns. The reason why the filling film-forming material for suppressing collapse of semiconductor substrate patterns has the above-mentioned composition and thereby exhibits the above-mentioned effect is not necessarily clear, but can be inferred, for example, as follows.

[0048] That is, because the filling film forming material for suppressing collapse of semiconductor substrate patterns uses (A) a polymer having a structural unit represented by the general formula (1) above, it can be increased in molecular weight by a crosslinking reaction with (B) a residual solvent elimination promoter during heat treatment, thereby imparting heat resistance to the filling film. Such a filling film for suppressing collapse of substrate patterns easily maintains its strength by suppressing thermal melting even when partially or entirely exposed to high temperatures during removal from the substrate by dry etching or other methods. This allows for reliable removal by dry etching while suppressing collapse of the substrate pattern. On the other hand, as the aspect ratio of the substrate pattern increases, residual solvent in the filling film filling the recesses becomes more difficult to remove. Heat treatment removes the residual solvent contained in the polymer (A) filling the recesses, but at the same time, curing of the filling film progresses, which causes the residual solvent trapped in the cured film to foam and easily form voids. In the composition containing only a specific polymer and a solvent, which is known in the prior art WO 2018 / 074535, the residual solvent in the specific polymer foams when filling a high aspect ratio pattern substrate, resulting in the problem of voids being formed in the filling film.

[0049] In contrast, the filling film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention includes a (B) residual solvent elimination promoter, which facilitates elimination of the residual solvent retained by the (A) polymer from the filling film, enabling the formation of a void-free filling film. The mechanism by which the residual solvent in the (A) polymer is easily eliminated is believed to be that the high-level crosslinking between the (A) polymer and the (B) residual solvent elimination promoter compound reduces the affinity between the (A) polymer and the (C) solvent, making the (C) solvent more volatile. On the other hand, in a composition known in prior art Patent Publication No. 6550760, which contains a specific polymer, a specific crosslinking agent, an acid generator, and a solvent, the specific polymer exhibits insufficient residual solvent elimination, leading to the formation of voids in the filling film when filling high-aspect-ratio patterned substrates. For this reason, the polymer structure of the present invention is preferably a polymer structure having a structural unit represented by the general formula (1) above.

[0050] Furthermore, when an acid generator is included in a filler film-forming material for suppressing collapse of semiconductor substrate patterns, the catalytic action of the generated acid accelerates the crosslinking reaction between (A) the polymer and (B) the residual solvent removal promoter, resulting in rapid shrinkage of the filler film, which exerts strong physical stress on the substrate pattern and makes it more likely to cause curvature of the substrate pattern. Furthermore, because the curing of the filler film is completed before the removal of the residual solvent is complete, the residual solvent trapped in the cured film tends to foam and form voids. Because the filler film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention does not contain an acid generator, the mild crosslinking reaction between (A) the polymer and (B) the residual solvent removal promoter promotes the removal of the residual solvent, and stress on the substrate pattern is suppressed, making it easier to maintain strength, thereby providing a filler film-forming material for suppressing collapse of semiconductor substrate patterns with excellent filling properties.

[0051] The filler film-forming material for suppressing collapse of semiconductor substrate patterns can be formed into a coating film with a thickness ranging from a lower limit of 50 nm to an upper limit of 6,000 nm by adjusting the solids concentration of the filler film-forming material for suppressing collapse of semiconductor substrate patterns, and is therefore useful as a filler film for various microstructures prone to collapse of substrate patterns, such as line-and-space patterns in logic FinFet structures, line-and-space patterns and island patterns in DRAM STI structures, pillar patterns in DRAM capacitor structures, and hole patterns and slit patterns in 3D-NAND cell structures.

[0052] [(A) Polymer] The polymer (A) contained in the filling film-forming material for suppressing collapse of a semiconductor substrate pattern of the present invention has a structural unit represented by the following general formula (1). [ka] (In the general formula (1), R 01is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1.

[0053] By using a polymer having a structural unit represented by the above general formula (1), it is possible to provide a filling film-forming material for suppressing collapse of a semiconductor substrate pattern, which has excellent substitution affinity with a cleaning solution or a rinse solution, fluidity, and affinity with the substrate.

[0054] In the above general formula (1), R 01 Examples of the saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms represented by the formula (I) include monovalent saturated hydrocarbon groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, and a tert-pentyl group; monovalent unsaturated chain hydrocarbon groups such as an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, an ethynyl group, and a propynyl group; Examples of the monovalent hydrocarbon group include monocyclic saturated cyclic hydrocarbon groups such as cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; monovalent monocyclic unsaturated cyclic hydrocarbon groups such as cyclobutenyl, cyclopentenyl, and cyclohexenyl groups; monovalent polycyclic cyclic hydrocarbon groups such as norbornyl and adamantyl groups; and monovalent aromatic hydrocarbon groups such as phenyl, methylphenyl, naphthyl, methylnaphthyl, anthryl, and methylanthryl groups.

[0055] Above R 01Examples of the organic group represented by the formula (I) include alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, and an n-hexyloxy group; and alkoxycarbonyl groups such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, an i-butoxycarbonyl group, a sec-butoxycarbonyl group, a t-butoxycarbonyl group, an n-pentyloxycarbonyl group, and an n-hexyloxycarbonyl group.

[0056] Some or all of the hydrogen atoms of the saturated hydrocarbon group, unsaturated chain hydrocarbon group, monocyclic saturated cyclic hydrocarbon group, monocyclic unsaturated cyclic hydrocarbon group, polycyclic cyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, alkoxycarbonyl group, etc. may be substituted, and examples of the substituent include halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; a hydroxyl group, a cyano group, a carboxy group, a nitro group, an amino group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an alkoxycarbonyloxy group, an aryl group, and an aliphatic heterocyclic group such as a lactone group; and aromatic heterocyclic groups such as a furyl group and a pyridyl group.

[0057] Above R 01 From the viewpoint of raw material availability, a methyl group is preferred as the organic group represented by the formula:

[0058] In the general formula (1), examples of the divalent organic group having 1 to 30 carbon atoms represented by X include alkanediyl groups such as methylene, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octanediyl, and decanediyl groups; monocyclic cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, cyclodecanediyl, methylcyclohexanediyl, and ethylcyclohexanediyl groups; bicyclo[2.2.1]heptanediyl, bicyclo[2.2.2]octanediyl, and tricyclo[5.2.1.0]octanediyl groups; 2,6 ]decanediyl group (dicyclopentylene group), tricyclo[3.3.1.1 3,7 ]decanediyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Polycyclic cycloalkanediyl groups such as dodecanediyl group and adamantanediyl group, and arenediyl groups such as phenylene group and naphthylene group.

[0059] Examples of the alkanediyloxy group represented by X include groups formed by combining the above alkanediyl group with an oxygen atom, and examples of the cycloalkanediyloxy group represented by X include groups formed by combining the above cycloalkanediyl group with an oxygen atom.

[0060] Some or all of the hydrogen atoms of the alkanediyl group, cycloalkanediyl group, alkanediyloxy group, cycloalkanediyloxy group, and arenediyl group may be substituted, and examples of the substituent include the above-mentioned R 01 Examples of the substituent that the organic group represented by the following formula may have include the same groups as those mentioned above.

[0061] Examples of the organic group represented by X include groups represented by the following formulas. [ka] (In the above formula, * represents a bond.)

[0062] From the viewpoint of raw material availability, a methylene group is preferable as the above X.

[0063] (A) Specific examples of polymers having a structural unit represented by the above general formula (1) include, but are not limited to, the following. From the viewpoint of raw material availability, (AX-1) or (AX-3) is preferred, and (AX-3) is particularly preferred. [ka]

[0064] The ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the polymer (A) in terms of polystyrene as determined by gel permeation chromatography is 2.50≦Mw / Mn≦9.00, preferably 3.00≦Mw / Mn≦8.00.

[0065] If the Mw / Mn of the (A) polymer used in the filling film-forming material for suppressing collapse of semiconductor substrate patterns is outside this range, the fluidity of the filling film will be low, and even when combined with the (B) residual solvent removal promoter, it will not be possible to provide a filling film-forming material for suppressing collapse of semiconductor substrate patterns that has excellent filling properties.

[0066] The weight average molecular weight Mw of the polymer (A) as measured by gel permeation chromatography in terms of polystyrene is preferably 1,500≦Mw≦20,000, more preferably 3,000≦Mw≦15,000, and particularly preferably 4,000≦Mw≦9,000.

[0067] By controlling the Mw of the polymer (A) used in the filler film-forming material for suppressing collapse of semiconductor substrate patterns within this range, the fluidity of the filler film can be increased, and by combining it with the residual solvent removal promoter (B), a filler film-forming material for suppressing collapse of semiconductor substrate patterns can be provided that has excellent fillability. In addition, a filler film with excellent film thickness uniformity and a small amount of sublimation can be formed.

[0068] The polymer (A) may contain a polymer having a structural unit represented by the following general formula (3) in addition to the structural unit represented by the formula (1). [ka] (In the general formula (3), R 03 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, p is 0 or 1, and R 01 and X are the same as above.)

[0069] In general formula (3), R 03 Examples of the saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms include R 01 Similar examples include:

[0070] Furthermore, a preferred embodiment of the general formula (3) is R 03 is an alkyl group having 1 to 30 carbon atoms, or a polymer having a structural unit represented by any of the structures represented by the following general formula (4). [ka] (In the general formula (4), * represents a bonding site to an oxygen atom, and R A represents an optionally substituted divalent organic group having 1 to 10 carbon atoms, R B is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms.

[0071] In the above general formula (4), R A Examples of the divalent organic group having 1 to 10 carbon atoms represented by the formula (I) include alkanediyl groups such as a methylene group, an ethanediyl group, a propanediyl group, a butanediyl group, a pentanediyl group, a hexanediyl group, an octanediyl group, and a decanediyl group, and arenediyl groups such as a benzenediyl group, a methylbenzenediyl group, and a naphthalenediyl group.

[0072] In the above general formula (4), R BExamples of the monovalent organic group having 1 to 10 carbon atoms represented by the formula (I) include alkyl groups such as a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, and n-decyl group, and aryl groups such as a phenyl group, tolyl group, xylyl group, mesityl group, and naphthyl group.

[0073] Some or all of the hydrogen atoms of the alkanediyl group, arenediyl group, alkyl group, aryl group, etc. may be substituted, and examples of the substituent include the above-mentioned R 01 Examples of the substituent that the organic group represented by the following formula may have include the same groups as those mentioned above.

[0074] Particularly preferred examples include the structure shown below. When the material has such a structure, it is possible to provide a material for forming a filling film for suppressing collapse of semiconductor substrate patterns, which has good fluidity and improved filling properties, and is capable of forming a filling film with a small amount of residual solvent. Furthermore, it has good heat resistance and film formability, suppresses the generation of sublimates during heat curing, suppresses contamination of the equipment by the sublimates, and suppresses the occurrence of coating defects. [ka] (In the above formula, * represents the bonding site to the oxygen atom.)

[0075] Specific examples of polymers having a structural unit represented by the above general formula (3) include, but are not limited to, the following: From the viewpoint of raw material availability, (AY-1) or (AY-3) is preferred, and (AY-3) is particularly preferred. [ka]

[0076] The content of the polymer having the structural unit of general formula (3) preferably satisfies the relationship a+b=100, b≦90, and more preferably b≦70, where a is the proportion of the general formula (1) and b is the proportion of the general formula (3).

[0077] By controlling the proportion of the polymer of general formula (3) within this range, it is possible to improve the filling performance for the patterned substrate while ensuring affinity with the cleaning solution or rinsing solution, and also to reduce the occurrence of cracks in the filling film caused by insufficient adhesion between the patterned substrate and the filling film.

[0078] Furthermore, as described above, it is possible to obtain an equivalent composition by not only mixing two types of polymers in a desired ratio but also controlling the ratio of substituents in one type of polymer. In this case, a polymer represented by the following general formula (5) is used, and R 04 It is possible to prepare it by controlling the ratio of the structure that constitutes R. 04 When the ratio of hydrogen atoms in the structure constituting the formula (I) is a and the ratio of alkyl groups having 1 to 10 carbon atoms or the structure represented by the general formula (4) is b, the relationship of a+b=100 is satisfied, and in this case, the ratio preferably satisfies the relationship of b≦90, and the relationship of b≦70 can be exemplified as a more preferable ratio. [ka] (In the above general formula (5), R 04 is either a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, or a structure represented by the general formula (4), and 04 In the structure constituting the formula (1), when the ratio of hydrogen atoms is a and the ratio of alkyl groups having 1 to 10 carbon atoms or the structure represented by the general formula (4) is b, the relationship of a+b=100 is satisfied. 01 , X is the same as above.)

[0079] The lower limit of the content of the polymer (A) in the filling film-forming material for suppressing collapse of a semiconductor substrate pattern is preferably 0.1% by mass, more preferably 3% by mass, and even more preferably 5% by mass, while the upper limit of the content is preferably 50% by mass, more preferably 40% by mass, and even more preferably 35% by mass.

[0080] By setting the content of the (A) polymer within the above range, the coating film thickness of the filler film forming material for suppressing collapse of semiconductor substrate patterns can be formed from a lower limit of 50 nm to an upper limit of 6000 nm, making it useful as a filler film for various microstructures prone to collapse of substrate patterns, such as line-and-space patterns in logic FinFet structures, line-and-space patterns and island patterns in DRAM STI structures, pillar patterns in DRAM capacitor structures, and hole patterns and slit patterns in 3D-NAND cell structures.

[0081] The amount of metal impurities in the polymer (A) is preferably 100 ppb or less, more preferably 10 ppb or less, and even more preferably 5 ppb or less, in terms of mass ratio.

[0082] The metals are preferably Li, Na, Mg, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Sn, Pb, Au, Co, Ti, Ag, Cd, V, As, Ba, and W, and more preferably Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti. Metal impurities of the above elements include all those present in the polymer in the form of metal fine particles, ions, colloids, complexes, oxides, or nitrides, regardless of whether they are dissolved or undissolved.

[0083] By controlling each metal impurity within the above range, it is possible to reduce the amount of metal impurities on the substrate surface after the filling film filled in the uneven pattern is removed by dry etching, and it is possible to prevent a decrease in device yield and reliability.

[0084] The type and content of the metal in the polymer can be measured by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) or the like.

[0085] [(B) Residual solvent removal promoter] The (B) residual solvent removal promoter contains a compound represented by the following general formula (2). This promotes a crosslinking reaction with the (A) polymer in the filling film, facilitating the removal of residual solvent retained by the (A) polymer from the filling film, thereby enabling the formation of a void-free filling film. Furthermore, since the compound represented by the following general formula (2) has a sufficient crosslinking rate, the present invention does not include an acid generator. Here, the term "acid generator" refers to an additive that generates acid when exposed to heat or light, such as an onium salt compound such as a sulfonium salt or an iodonium salt. When an acid generator is contained, the crosslinking reaction between the (A) polymer and the (B) residual solvent removal promoter accelerates due to the catalytic action of the acid, causing rapid shrinkage of the filling film, which can exert strong physical stress on the substrate pattern and potentially result in curvature of the substrate pattern. Furthermore, since the curing of the filling film is completed before the removal of the residual solvent is complete, the residual solvent trapped in the cured film may foam and form voids. [ka] (In the general formula (2), Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 02 is a hydrogen atom or a methyl group, and q is an integer of 1 to 5.

[0086] In the above general formula (2), Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. q is an integer of 1 to 5, and more preferably 2 or 3. When Q is a q-valent hydrocarbon group having 1 to 20 carbon atoms, Q is a q-valent hydrocarbon group obtained by removing q hydrogen atoms from a hydrocarbon having 1 to 20 carbon atoms. More specific examples of the hydrocarbon having 1 to 20 carbon atoms in this case include methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane.

[0087] R in the above general formula (2) 02is a hydrogen atom or a methyl group, preferably a methyl group.

[0088] Specific examples of the compound represented by the general formula (2) include, but are not limited to, the following compounds: 02 is the same as above. q=3 and R 02 is preferably a methyl group from the viewpoints of curability, improvement of film thickness uniformity, and ability to remove residual solvents, and hexamethoxymethylated products of triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are particularly preferred.

[0089] [ka]

[0090] [ka]

[0091] The (B) residual solvent elimination promoter can be used alone or in combination of two or more. The content of the (B) residual solvent elimination promoter is 0.1% to 40% by mass, preferably 10% to 30% by mass, relative to 100 parts by mass of the (A) polymer. If the added amount is less than 0.1% by mass, the crosslinking reactivity with the (A) polymer is insufficient, and the elimination of the residual solvent contained in the (A) polymer in the filler film cannot be promoted. On the other hand, if the added amount exceeds 40% by mass, the crosslinking reaction between the (A) polymer and the (B) residual solvent elimination promoter slows down, resulting in the generation of sublimates and a deterioration in film thickness uniformity.

[0092] [(C) Organic solvent] The filling film-forming material for suppressing collapse of semiconductor substrate patterns contains (C) an organic solvent. Examples of (C) organic solvents include ketone-based solvents, amide-based solvents, ether-based solvents, ester-based solvents, and mixtures thereof. There are no particular limitations on the organic solvent, as long as it dissolves the (A) polymer, (B) residual solvent elimination promoter, and, if included, the (D) surfactant, etc. (described below). Specifically, solvents with a boiling point of less than 180°C, such as those described in paragraphs

[0091] and

[0092] of JP 2007-199653 A, can be used. Among these, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and mixtures of two or more of these are preferred. The amount of organic solvent blended is preferably 50 to 1,800 parts, more preferably 150 to 1,500 parts, per 100 parts by mass of the (A) polymer.

[0093] Such a material for forming a filling film for suppressing collapse of semiconductor substrate patterns can be applied by spin coating, and therefore a filling film for suppressing collapse of semiconductor substrate patterns can be formed with a uniform film thickness and high filling properties.

[0094] Furthermore, the organic solvent in the filling film forming material for suppressing collapse of semiconductor substrate patterns of the present invention can contain a high-boiling point solvent in addition to the above-mentioned solvents having a boiling point of less than 180°C. The high-boiling point solvent is preferably one or more organic solvents having a boiling point of 180°C or higher (a mixture of a solvent having a boiling point of less than 180°C and a solvent having a boiling point of 180°C or higher). The high-boiling point solvent is not particularly limited as long as it can dissolve the polymer and / or the residual solvent removal promoter, and may be any of hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc. Specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, triethylene Glycol diacetate, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,Examples of the diester include 6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, and dibutyl adipate, and these may be used alone or in combination.

[0095] The boiling point of the high-boiling solvent may be appropriately selected according to the temperature at which the filled film is heat-treated, and the boiling point of the added high-boiling solvent is preferably 180°C to 300°C, more preferably 200°C to 300°C. Such a boiling point allows for appropriate speed of volatilization during baking (heat treatment), ensuring sufficient thermal fluidity. Furthermore, since the solvent does not remain in the film after baking, it does not adversely affect film properties such as etching resistance.

[0096] Furthermore, when using the high-boiling point solvent, the blending amount of the high-boiling point solvent is preferably 1 to 50 parts by mass per 100 parts by mass of the solvent having a boiling point of less than 180° C. Such a blending amount can impart sufficient thermal fluidity during baking, and does not remain in the film, leading to deterioration of film properties such as etching resistance.

[0097] In the case of such a filling film forming material for preventing collapse of a semiconductor substrate pattern, by adding a high boiling point solvent to the above-mentioned filling film forming material for preventing collapse of a semiconductor substrate pattern, the filling film forming material for preventing collapse of a semiconductor substrate pattern also has high filling properties.

[0098] [(D) Surfactant] A surfactant (D) can be added to the filling film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention to improve the coating properties during spin coating. Examples of surfactants that can be used include those described in paragraphs

[0142] to

[0147] of JP-A-2009-269953. Examples include nonionic surfactants and fluorine-based surfactants. When a surfactant is added, the amount added is preferably 0.01 to 10 parts, more preferably 0.05 to 5 parts, per 100 parts of the polymer.

[0099] [Amount of metal impurities] From the viewpoint of reducing contamination of the substrate pattern, it is preferable that the filling film forming material for suppressing collapse of the semiconductor substrate pattern contains as few metal impurities as possible. The amount of metal impurities in the filling film forming material for suppressing collapse of the semiconductor substrate pattern is preferably 10 ppb or less by mass, more preferably 5 ppb or less, even more preferably 3 ppb or less, and particularly preferably 1 ppb or less. By controlling the amount of each metal impurity within the above range, the amount of metal impurities on the substrate surface can be reduced after the filling film filled in the uneven pattern is removed by dry etching.

[0100] The metals are preferably Li, Na, Mg, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Sn, Pb, Au, Co, Ti, Ag, Cd, V, As, Ba, and W, and more preferably Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti. Metal impurities of the above elements include all metal impurities present in the material for forming a filling film for suppressing collapse of semiconductor substrate patterns in the form of metal fine particles, ions, colloids, complexes, oxides, or nitrides, whether dissolved or undissolved.

[0101] By controlling the amount of each metal impurity within the above range, it is possible to reduce the amount of metal impurities on the substrate surface after the filling film that has filled the uneven pattern is removed by dry etching, thereby preventing a decrease in device yield and reliability.

[0102] After the filling film filling the uneven pattern was removed by dry etching, the amount of the above metal impurities on the substrate surface was 2.0 × 10E +10 atoms / cm 2 Preferably less than 1.0 x 10E +10 atoms / cm 2 The following is more preferable: The metal content on the substrate surface after removal of the filling film can be measured by an Expert VPD-ICP-MS manufactured by IAS Corporation or the like.

[0103] [Method of manufacturing a filling film forming material for preventing collapse of semiconductor substrate patterns] The filler film-forming material for suppressing collapse of semiconductor substrate patterns can be produced by mixing (A) a polymer, (B) a residual solvent elimination promoter, (C) an organic solvent, and optional components added as needed, and then filtering the resulting solution through a filter with a pore size of, for example, approximately 0.02 μm. The lower limit of the solids concentration of the filler film-forming material for suppressing collapse of semiconductor substrate patterns is preferably 0.1% by mass, more preferably 3% by mass, and even more preferably 5% by mass. The upper limit of the solids concentration is preferably 50% by mass, more preferably 40% by mass, and even more preferably 35% by mass. Here, the "solids" in the filler film-forming material for suppressing collapse of semiconductor substrate patterns refers to components other than (C) the organic solvent.

[0104] By setting the solids concentration of the filler film-forming material for suppressing collapse of semiconductor substrate patterns within the above range, it is possible to form a coating film of the filler film-forming material for suppressing collapse of semiconductor substrate patterns with a thickness ranging from a lower limit of 50 nm to an upper limit of 6000 nm, making it useful as a filler film for various microstructures prone to collapse of substrate patterns, such as line-and-space patterns in logic FinFet structures, line-and-space patterns and island patterns in DRAM STI structures, pillar patterns in DRAM capacitor structures, and hole patterns and slit patterns in 3D-NAND cell structures.

[0105] Furthermore, the obtained filler film-forming material for suppressing collapse of semiconductor substrate patterns is preferably further filtered through a nylon filter (e.g., a filter using a nylon 66 membrane as a filtration medium), an ion exchange filter, or a filter utilizing adsorption due to zeta potential. In this way, by filtering through a nylon filter, an ion exchange filter, or a filter utilizing adsorption due to zeta potential, the metal content in the filler film-forming material for suppressing collapse of semiconductor substrate patterns can be easily and reliably reduced, and a filler film-forming material for suppressing collapse of semiconductor substrate patterns with a relatively low metal content can be obtained at low cost. The metal content of the filler film-forming material for suppressing collapse of semiconductor substrate patterns can also be reduced by purification using known methods, such as chemical purification methods such as water washing and liquid-liquid extraction, or a combination of chemical purification methods with physical purification methods such as ultrafiltration and centrifugation.

[0106] <Method for processing semiconductor substrates> A process for suppressing pattern collapse of a semiconductor substrate having a high aspect ratio, for example, an aspect ratio of 5 or more, using the filling film-forming material for suppressing semiconductor substrate pattern collapse of the present invention is specifically shown below with reference to FIG.

[0107] The semiconductor substrate processing method is a method for performing a drying process on a semiconductor substrate having a concave-convex pattern formed on a surface thereof, the method comprising: (1) a step of cleaning the semiconductor substrate 1 on which the pattern has been formed with a cleaning liquid 2, or a step of cleaning the semiconductor substrate on which the pattern has been formed with the cleaning liquid 2 and then replacing it with a rinsing liquid 2 (FIG. 1(A)); (2) A step of replacing the cleaning liquid 2 or the rinsing liquid 2 with the above-described filling film forming material for suppressing collapse of a semiconductor substrate pattern and filling the filling film 3 (FIG. 1(B)); (3) A step of hardening the filling film 3 by heat treating it at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds (hardened filling film 3a, FIG. 1(C)). (4) A step of removing the hardened filling film 3a from the semiconductor substrate by dry etching (semiconductor substrate 1a after filling film removal, FIG. 1(D)). It is preferable that the method further comprises the steps of:

[0108] A method for treating a semiconductor substrate using the filler film-forming material for suppressing collapse of a semiconductor substrate pattern preferably includes a wet etching or dry etching step, followed by at least one step selected from a cleaning step in which the semiconductor substrate is cleaned with a cleaning liquid and a rinsing step in which the semiconductor substrate is rinsed with a rinse liquid, followed by applying the filler film-forming material for suppressing collapse of a semiconductor substrate pattern to the semiconductor substrate on which the pattern has been formed and drying. In this case, it is more preferable to apply the filler film-forming material for suppressing collapse of a semiconductor substrate pattern while the cleaning liquid or rinsing liquid is retained on the substrate, thereby replacing the cleaning liquid or rinsing liquid to form a coating film. Because the semiconductor substrate treatment method uses the filler film-forming material for suppressing collapse of a semiconductor substrate pattern, the method exhibits excellent suppression of collapse of the semiconductor substrate pattern and low metallurgy on the semiconductor substrate surface after removal of the filler film.

[0109] The filling film forming material for suppressing collapse of a semiconductor substrate pattern of the present invention can also be applied to a processing method such as that shown in FIG. 2 as a resist underlayer film in a multilayer resist process after filling a semiconductor substrate pattern.

[0110] A method for forming a different concave-convex pattern on a surface of a semiconductor substrate, the method comprising the steps of drying the semiconductor substrate and forming a different concave-convex pattern on the surface of the semiconductor substrate, the method comprising the steps of: (1) a step of cleaning the semiconductor substrate on which the pattern has been formed (semiconductor substrate 4 having a high aspect ratio pattern (Pattern-A)) with a cleaning liquid, or a step of cleaning the semiconductor substrate on which the pattern has been formed with the cleaning liquid and then replacing the cleaning liquid with a rinse liquid; (2) A step of replacing the cleaning liquid or rinsing liquid with the above-described filling film forming material for suppressing collapse of a semiconductor substrate pattern and filling the filling film 5 (FIG. 2(E)); (3) A step of hardening the filling film by heat treating it at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds (hardened filling film 5a, FIG. 2(F)). (4) forming a silicon-containing resist intermediate film 6 on the hardened filling film 5a using a silicon-containing resist intermediate film material (FIG. 2(G)); (5) forming a resist upper layer film 7 on the silicon-containing resist intermediate film 6 using a photoresist composition (FIG. 2(H)); (6) forming a circuit pattern 7a on the resist upper layer film (FIG. 2(I)); (7) A step of transferring a pattern to the silicon-containing resist intermediate film by etching using the resist upper layer film on which the circuit pattern 7a has been formed as a mask (silicon-containing resist intermediate film pattern 6a, FIG. 2(J)); (8) A step of transferring a pattern to the hardened filling film by etching using the silicon-containing resist intermediate film to which the pattern has been transferred as a mask (filling film pattern 5b, FIG. 2(K)); (9) A step of forming a different concave-convex pattern from the concave-convex pattern by etching the semiconductor substrate having the concave-convex pattern formed on its surface using the hardened filling film to which the pattern has been transferred as a mask (semiconductor substrate pattern (after formation of Pattern-B) 4a, FIG. 2(L)); (10) Step of removing the hardened filling film from the semiconductor substrate by dry etching (FIG. 2(M)). A method for processing a semiconductor substrate is provided.

[0111] Thus, a filling film coated with the filling film-forming material for suppressing semiconductor substrate pattern collapse of the present invention can be suitably used as a resist underlayer film for a semiconductor substrate having a concave-convex pattern formed on its surface. Because the heat-treated filling film has excellent solvent resistance, it can be used in various pattern formation methods, such as a multilayer resist process in which a silicon-containing intermediate film (silicon-containing resist intermediate film, inorganic hard mask intermediate film) is formed on the filling film without removing it, and a conventional organic photoresist film is formed on top of that as a resist upper layer film. After a circuit pattern formed using a photoresist composition is transferred by etching to form a semiconductor substrate pattern having a concave-convex pattern coated with the filling film, the filling film can be removed by dry etching. By continuing to use the highly clean filling film-forming material for suppressing semiconductor substrate pattern collapse as a resist underlayer film in a multilayer resist process without removing it, it is possible to omit the steps of removing the filling film for suppressing semiconductor substrate pattern collapse applied after semiconductor substrate cleaning and applying a resist underlayer film for the multilayer resist process. By replacing a drying step that does not use a filler film-forming material for suppressing collapse of a semiconductor substrate pattern, such as drying using 2-propanol, with the filler film-forming material for suppressing collapse of a semiconductor substrate pattern of the present invention, it is possible to omit the drying step, thereby contributing to process rationalization. Note that the use is not limited to drying semiconductor substrates, and the material can also be used as a resist underlayer film in a multilayer resist process used to fill a semiconductor substrate pattern after drying the semiconductor substrate in the manufacturing process of a semiconductor device.

[0112] Examples of the multilayer resist process include a silicon-containing two-layer resist process, a three-layer resist process using a silicon-containing intermediate film, a four-layer resist process using a silicon-containing intermediate film and an organic thin film, and a silicon-free two-layer resist process. From the viewpoints of anti-reflection performance and cost, a three-layer resist process using a silicon-containing intermediate film is preferred.

[0113] As the silicon-containing resist interlayer in the above multilayer resist process, a polysilsesquioxane-based interlayer is also preferably used. By imparting an anti-reflection effect to the silicon-containing resist interlayer, reflection can be suppressed. As a silicon-containing resist interlayer with an anti-reflection effect, anthracene is preferably used for exposure at 248 nm and 157 nm, and polysilsesquioxane is preferably used for exposure at 193 nm, with pendant light-absorbing groups having phenyl groups or silicon-silicon bonds, and crosslinked by acid or heat.

[0114] In this case, forming a silicon-containing resist intermediate film by spin coating is easier and more cost-effective than forming it by CVD.

[0115] When forming an inorganic hard mask intermediate film on the filling film, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, or the like. For example, methods for forming silicon nitride films are described in JP 2002-334869 A and WO 2004 / 066377 A. The thickness of the inorganic hard mask intermediate film is preferably 5 to 200 nm, more preferably 10 to 100 nm. Furthermore, a SiON film, which is highly effective as an anti-reflective film, is most preferably used as the inorganic hard mask intermediate film. When forming the SiON film, the semiconductor substrate temperature is 300 to 500°C, so the filling film must be able to withstand temperatures of 300 to 500°C.

[0116] The resist top layer film in the above multilayer resist process may be either positive or negative, and the same photoresist compositions as those commonly used can be used. After spin-coating the photoresist composition, pre-baking is performed, preferably at 60 to 180°C for 10 to 300 seconds. Thereafter, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist top layer film pattern. The thickness of the resist top layer film is not particularly limited, but is preferably 30 to 500 nm, and more preferably 50 to 400 nm.

[0117] In forming the circuit pattern of the resist upper layer film (resist upper layer film pattern) in the above multilayer resist process, it is preferable to form the circuit pattern by lithography using light with a wavelength of 10 nm or more and 300 nm or less, direct writing with an electron beam, nanoimprinting, or a combination of these.

[0118] Examples of exposure light include high-energy rays with a wavelength of 300 nm or less, specifically far ultraviolet rays, KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F2 laser light (157 nm), Kr2 laser light (146 nm), Ar2 laser light (126 nm), soft X-rays (EUV) of 3 to 20 nm, electron beams (EB), ion beams, X-rays, and the like.

[0119] In forming the circuit pattern, it is preferable to develop the circuit pattern using an alkali developer or an organic solvent.

[0120] Examples of cleaning solutions used to clean semiconductor substrates having the above-mentioned concave-convex pattern include a stripper containing sulfate ions, a cleaning solution containing chloride ions, a cleaning solution containing fluoride ions, an alkaline cleaning solution containing a nitrogen compound, and a cleaning solution containing phosphoric acid. The cleaning solution preferably contains hydrogen peroxide. Cleaning steps using two or more cleaning solutions may be performed continuously. A preferred cleaning solution containing sulfate ions is sulfuric acid / hydrogen peroxide (SPM), which is a mixture of hydrogen peroxide and sulfuric acid, and is suitable for removing organic materials such as resist. A preferred cleaning solution containing chloride ions is a mixed aqueous solution of hydrogen peroxide and hydrochloric acid (SC-2), which is suitable for removing metals. An example of a cleaning solution containing fluoride ions is a mixed aqueous solution of hydrofluoric acid and ammonium fluoride. A preferred alkaline cleaning solution containing a nitrogen compound is a mixed aqueous solution of hydrogen peroxide and ammonia (SC-1), which is suitable for removing particles.

[0121] Examples of the rinse liquid used to rinse the semiconductor substrate on which the above-mentioned concavo-convex pattern has been formed include ultrapure water and water-soluble alcohol. 2-Propanol is a preferred water-soluble alcohol. Rinsing steps using two or more rinse liquids may be performed consecutively. It is preferred to perform an alcohol rinse treatment in which ultrapure water is substituted with 2-propanol after rinsing with water, and then apply the filling film-forming material for suppressing collapse of the semiconductor substrate pattern.

[0122] The cleaning liquid or rinsing liquid preferably contains at least one of water, a water-soluble alcohol, and a fluorine compound.

[0123] The method for applying the filling film forming material for suppressing collapse of semiconductor substrate patterns to the semiconductor substrate is not particularly limited, and can be carried out by any appropriate method such as spin coating, casting coating, roll coating, or the like.

[0124] The method for drying the coating film coated with the filling film-forming material for suppressing collapse of semiconductor substrate patterns is not particularly limited, but is usually performed by heating in an atmospheric atmosphere. The lower limit of the heating temperature is not particularly limited, but is preferably 40°C, more preferably 60°C, and even more preferably 100°C. The upper limit of the heating temperature is preferably 400°C, more preferably 350°C, and even more preferably 300°C. The lower limit of the heating time is preferably 15 seconds, more preferably 30 seconds, and even more preferably 45 seconds. The upper limit of the heating time is preferably 1,200 seconds, more preferably 600 seconds, and even more preferably 300 seconds.

[0125] In this way, by applying the filler film-forming material for suppressing collapse of semiconductor substrate pattern on a semiconductor substrate having a concave-convex pattern formed thereon and drying it, it is possible to fill the recesses of the pattern with the filler film-forming material for suppressing collapse of semiconductor substrate pattern. This makes it possible to suppress collapse of the pattern, such as when one pattern comes into contact with an adjacent pattern. Furthermore, because the filler film-forming material for suppressing collapse of semiconductor substrate pattern contains (A) a polymer, it can be crosslinked with (B) a residual solvent removal promoter during heat treatment to increase its molecular weight, thereby imparting heat resistance to the filler film. Such a filler film can easily maintain its strength by suppressing thermal melting even when partially or entirely exposed to high temperatures during removal from the semiconductor substrate by dry etching or the like. Therefore, it can be reliably removed by dry etching or the like while suppressing collapse of the semiconductor substrate pattern.

[0126] The atmosphere during baking may be not only air, but also an inert gas such as N2, Ar, or He. The atmosphere may have an oxygen concentration of less than 0.1%. The baking temperature and other conditions may be the same as those described above. Even if the semiconductor substrate on which the concavo-convex pattern is formed contains a material that is unstable when heated in an oxygen atmosphere, the crosslinking reaction of the filling film-forming material for suppressing collapse of the semiconductor substrate pattern can be promoted without causing deterioration of the semiconductor substrate.

[0127] The semiconductor substrate on which the above-mentioned concave-convex pattern is formed is not particularly limited as long as it is a pattern formed on a semiconductor substrate other than a resist pattern. However, a semiconductor substrate having a semiconductor substrate pattern formed on at least one surface and containing silicon atoms or metal atoms is preferred, and a semiconductor substrate whose main component is a metal, metal nitride, metal oxide, silicon oxide, silicon nitride film, silicon, or a mixture thereof is more preferred. Here, the "main component" refers to the component with the highest content, for example, a component with a content of 50 mass% or more. Examples of the metal atoms include titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, silver, gold, aluminum, indium, gallium, arsenic, palladium, iron, tantalum, iridium, cobalt, manganese, and molybdenum.

[0128] Examples of the material constituting the semiconductor substrate pattern include the same materials as those exemplified as the material of the semiconductor substrate.

[0129] The shape of the semiconductor substrate pattern is not particularly limited, and examples thereof include fine structures such as line-and-space patterns, island patterns, hole patterns, pillar patterns, and slit patterns. The upper limit of the average spacing of the line-and-space patterns and island patterns is preferably 300 nm, more preferably 100 nm, even more preferably 50 nm, and particularly preferably 30 nm. The upper limit of the average spacing of the hole patterns and pillar patterns is preferably 300 nm, more preferably 150 nm, and even more preferably 100 nm. The upper limit of the average spacing of the slit patterns is preferably 2,000 nm, more preferably 1,500 nm. By applying the semiconductor substrate processing method to a semiconductor substrate on which such a pattern with a fine spacing is formed, excellent collapse suppression properties of the semiconductor substrate pattern can be maximized.

[0130] The lower limit of the average height of the line-and-space pattern and island pattern is preferably 100 nm, more preferably 200 nm, even more preferably 300 nm, and particularly preferably 400 nm. The upper limit of the average width of the lines-and-spaces and islands of the semiconductor substrate (e.g., based on the center in the height direction) is preferably 50 nm, more preferably 40 nm, even more preferably 30 nm, and particularly preferably 20 nm. The lower limit of the aspect ratio (average pattern height / average pattern width) of the semiconductor substrate is preferably 5, more preferably 10, even more preferably 15, and particularly preferably 20.

[0131] The lower limit of the average height of the hole pattern is preferably 3,000 nm, more preferably 5,000 nm, even more preferably 7,000 nm, and particularly preferably 10,000 nm. The upper limit of the average width of the holes in the semiconductor substrate (e.g., based on the center in the height direction) is preferably 300 nm, more preferably 150 nm, and even more preferably 100 nm. The lower limit of the aspect ratio (average pattern height / average pattern width) of the semiconductor substrate is preferably 10, more preferably 30, even more preferably 50, and particularly preferably 100.

[0132] The lower limit of the average height of the pillar pattern is preferably 100 nm, more preferably 200 nm, even more preferably 300 nm, and particularly preferably 400 nm. The upper limit of the average width of the pillars of the semiconductor substrate (e.g., based on the center in the height direction) is preferably 50 nm, more preferably 40 nm, even more preferably 30 nm, and particularly preferably 20 nm. The lower limit of the aspect ratio (average pattern height / average pattern width) of the semiconductor substrate is preferably 5, more preferably 10, even more preferably 15, and particularly preferably 20.

[0133] The lower limit of the average height of the slit pattern is preferably 3,000 nm, more preferably 5,000 nm, even more preferably 7,000 nm, and particularly preferably 10,000 nm. The upper limit of the average width of the slits of the semiconductor substrate (e.g., based on the center in the height direction) is preferably 500 nm, more preferably 300 nm, and even more preferably 150 nm. The lower limit of the aspect ratio of the semiconductor substrate (average pattern height / average pattern width) is preferably 3, more preferably 5, even more preferably 10, and particularly preferably 15.

[0134] The filling film forming material for suppressing collapse of semiconductor substrate patterns can be widely applied regardless of the type of the microstructure.

[0135] In addition, the present invention preferably provides a method for treating a semiconductor substrate, which includes a step of filling a semiconductor substrate having an aspect ratio of 5 or more and a concave-convex pattern formed on its surface with the above-described filling film forming material for suppressing collapse of a semiconductor substrate pattern, to form a filling film, and a step of removing the filling film.

[0136] It is preferable that the coating film formed by applying the material for suppressing collapse of a semiconductor substrate pattern be capable of filling recesses in the pattern. That is, the material for forming a filling film for suppressing collapse of a semiconductor substrate pattern can be suitably used as a filling film. The thickness of the coating film is not particularly limited, but the lower limit of the average thickness of the coating film on the surface of the protruding portions of the semiconductor substrate pattern is preferably 0.01 μm, more preferably 0.02 μm, and even more preferably 0.05 μm. The upper limit of the average thickness is preferably 5 μm, more preferably 3 μm, even more preferably 2 μm, and particularly preferably 0.5 μm.

[0137] The coating film formed on the semiconductor substrate using the filling film-forming material for suppressing collapse of a semiconductor substrate pattern can be removed in a gas phase by, for example, heat treatment, plasma treatment, dry etching (ashing), ultraviolet irradiation, electron beam irradiation, etc., but removal by dry etching (ashing) is preferred.

[0138] Dry etching can be performed using a known dry etching apparatus. The etching gas used in dry etching can be appropriately selected depending on the elemental composition of the substrate pattern collapse suppression filling film to be etched, and examples of suitable gases include fluorine-based gases such as CHF3, CF4, C2F6, C3F8, and SF6; chlorine-based gases such as Cl2 and BCl3; oxygen-based gases such as O2, O3, and H2O; reducing gases such as H2, NH3, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H4, C3H6, C3H8, HF, HI, HBr, HCl, NO, and BCl3; and inert gases such as He, N2, and Ar. These gases can also be used in combination. [Example]

[0139] The present invention will be described in more detail below with reference to Synthesis Examples, Examples, and Comparative Examples, but is not limited thereto. Regarding the molecular weight and dispersity, the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent, and the dispersity (Mw / Mn) was calculated.

[0140] [Compound synthesis] Synthesis of polymer (A-1) Under a nitrogen atmosphere, 216.3 g of meta-cresol, 130.0 g of 37% formaldehyde solution, 10.8 g of oxalic acid, and 200 g of dioxane were added and reacted at an internal temperature of 100°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK (methyl isobutyl ketone) was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was recovered and evaporated to dryness under reduced pressure to obtain polymer (A-1). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and were found to be Mw = 7,000 and Mw / Mn = 7.5. [ka]

[0141] Synthesis of polymer (A-2) Under a nitrogen atmosphere, 160.2 g of 1,5-dihydroxynaphthalene, 64.9 g of 37% formaldehyde solution, and 300 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100 °C. A pre-mixed mixture of 8.0 g of paratoluenesulfonic acid monohydrate and 8.0 g of PGME was then slowly added dropwise, and the reaction was carried out at an internal temperature of 80 °C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of purified water. The organic layer was evaporated to dryness under reduced pressure. 300 g of THF was added to the residue to form a homogenous solution, which was then crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed twice with 500 g of hexane, and then recovered. The recovered crystals were dried in vacuo at 70 °C to obtain polymer (A-2). The weight average molecular weight (Mw) and the polydispersity (Mw / Mn) were determined by GPC, and were found to be Mw=4,000 and Mw / Mn=3.0. [ka]

[0142] Synthesis of polymer (A-3) Under a nitrogen atmosphere, 100.0 g of polymer (A-1), 172.3 g of potassium carbonate, and 500 g of DMF were added to form a homogeneous dispersion at an internal temperature of 50°C. 119.0 g of propargyl bromide was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 1,000 ml of methyl isobutyl ketone and 1,000 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was removed. The organic layer was further washed six times with 300 g of 3% aqueous nitric acid solution and 300 g of pure water, and then evaporated to dryness under reduced pressure. 300 g of THF was added to the residue to form a homogeneous solution, which was then crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed twice with 500 g of hexane, and then recovered. The recovered crystals were dried in vacuo at 70°C to obtain polymer (A-3). The weight average molecular weight (Mw) and the polydispersity (Mw / Mn) were determined by GPC, and were found to be Mw=10,000 and Mw / Mn=3.1. [ka]

[0143] Synthesis of polymer (A-4) Under a nitrogen atmosphere, 188.2 g of phenol, 48.7 g of 37% formaldehyde solution, 9.4 g of oxalic acid, and 200 g of dioxane were added and reacted at an internal temperature of 100°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was recovered, and the pressure was reduced to 2 mmHg at an internal temperature of 150°C to remove water, solvent, and residual monomers under reduced pressure, yielding polymer (A-4). The weight-average molecular weight (Mw) and polydispersity (Mw / Mn) were determined by GPC, revealing Mw = 1,500 and Mw / Mn = 1.5. [ka]

[0144] Synthesis of polymer (A-5) Under a nitrogen atmosphere, 188.2 g of phenol, 113.6 g of 37% formaldehyde solution, 9.4 g of oxalic acid, and 200 g of dioxane were added and reacted at an internal temperature of 100°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was recovered and concentrated to a yield of approximately 25 wt%. Then, 1,000 g of a 1:1 (weight ratio) mixture of methanol and pure water was added with stirring to precipitate the polymer. After allowing to stand for 1 hour, the supernatant was decanted. The precipitate was recovered and evaporated to dryness under reduced pressure to obtain Polymer (A-5). The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC to be Mw = 10,000 and Mw / Mn = 1.5. [ka]

[0145] Synthesis of polymer (A-6) Under a nitrogen atmosphere, 60.0 g of 2-vinylnaphthalene, 40.0 g of vinylbenzyl alcohol, 300 g of methyl ethyl ketone, and 5.0 g of dimethyl 2,2-azobisisobutyrate were added and reacted at an internal temperature of 80°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature and crystallized in 3,000 g of heptane. The precipitated crystals were separated by filtration, washed twice with 500 g of heptane, and then recovered. The recovered crystals were dried in a vacuum at 70°C to obtain polymer (A-6). The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, revealing Mw = 4,500 and Mw / Mn = 2.0. [ka]

[0146] [Preparation of filling film forming material for preventing semiconductor substrate pattern collapse] The components used in preparing the filling film-forming material for suppressing collapse of semiconductor substrate patterns are shown below.

[0147] [(A) Polymer] The polymers (A) (A-1) to (A-6) used in the filling film forming material for suppressing collapse of semiconductor substrate patterns are shown below. [ka]

[0148] [(B) Residual solvent removal promoter] The following shows each (B) residual solvent removal promoter used in the filling film forming material for suppressing collapse of semiconductor substrate patterns. [ka]

[0149] [Composition FM-1] 100 parts by weight of (A-1) as a polymer (A), 15 parts by weight of (B-1) as a residual solvent removal promoter (B), and 0.25 parts by weight of (D-1) FC-4430 (manufactured by 3M Corporation) as a surfactant (D-1) were dissolved in 1,150 parts by weight of (C-1) propylene glycol monomethyl ether acetate (PGMEA) as an organic solvent (C). The resulting solution was filtered through a membrane filter with a pore size of 0.02 μm to prepare a filling film-forming material (FM-1) for suppressing semiconductor substrate pattern collapse.

[0150] [Compositions FM-2 to FM-4 and Comparative FM-1 to FM-11] Each filling film-forming material for suppressing semiconductor substrate pattern collapse was prepared in the same manner as FM-1, except that the type and content of each component was as shown in Tables 1 to 3. In Tables 1 to 3, "-" indicates that the corresponding component was not used. The acid generator (TAG) used was the compound represented by the following formula (E-1), and the high-boiling point solvent (C-2) used was 1,6-diacetoxyhexane (boiling point 260°C). [ka]

[0151] [Table 1]

[0152] [Table 2]

[0153] [Table 3]

[0154] <Formation of filling film> The filling film forming materials for suppressing semiconductor substrate pattern collapse prepared in FM-1 to FM-4 and comparative FM-3 to FM-11 were applied to the surface of a semiconductor substrate having a concave-convex pattern formed thereon, and the substrate was baked in air at 250°C for 60 seconds to form a filling film. Three types of silicon wafers (semiconductor substrates A to C) having different concave-convex patterns formed thereon were used as the semiconductor substrates. Semiconductor substrate A: A silicon wafer having a line-and-space pattern with an aspect ratio of 40, with a height of 6,000 nm, an average line width of 150 nm, and an average pitch between each line of 400 nm. Semiconductor substrate B: A silicon wafer having a hole pattern with an aspect ratio of 20, with a height of 8,000 nm, an average hole width of 380 nm, and an average pitch between holes of 500 nm. Semiconductor substrate C: A silicon wafer having a line-and-space pattern with an aspect ratio of 13, with a height of 400 nm, an average line width of 30 nm, and an average pitch between each line of 45 nm.

[0155] The filling film forming materials for suppressing semiconductor substrate pattern collapse, FM-1 to 4 and Comparative FM-1 to 11, were evaluated for film thickness uniformity, filling property, and pattern collapse suppression property by the following methods. In addition, for Example 4-1 and Comparative Example 4-1, the amount of metal impurities on the semiconductor substrate surface after removing the filling film was evaluated by the following methods.

[0156] [Thickness uniformity] Cross sections of the silicon wafer substrates on which the above-mentioned filling films (FM-1 to 4 and comparative FM-3 to 11) were formed were cut out, and the film thickness uniformity of each filling film was evaluated using an FE-SEM (Hitachi High-Technologies Corporation's "S4800"). In comparative examples 1-1 and 1-2, no filling film was formed, so the coating properties were not evaluated. The evaluation points are shown below. Semiconductor substrate A: This is the film thickness on the pattern in the area where the uneven pattern is dense. Film thickness 1 at the center of the silicon wafer substrate and film thickness 2 at the outer periphery were measured, and if the difference in film thickness between film thickness 1 and film thickness 2 was 60 nm or less, it was evaluated as "A" (very good), if it was 61 to 90 nm, it was evaluated as "B" (good), and if it was 91 nm or more, it was evaluated as "C" (poor). Semiconductor substrate B: The film thickness 1 at the center of the silicon wafer substrate and the film thickness 2 at the outer periphery were measured, and if the difference between film thickness 1 and film thickness 2 was 100 nm or less, it was evaluated as "A" (very good), if it was 101 to 150 nm, it was evaluated as "B" (good), and if it was 151 nm or more, it was evaluated as "C" (poor). Semiconductor substrate C: The film thickness 1 at the center of the silicon wafer substrate and the film thickness 2 at the outer periphery were measured, and if the difference between film thickness 1 and film thickness 2 was 4 nm or less, it was evaluated as "A" (very good), if it was 5 to 6 nm, it was evaluated as "B" (good), and if it was 7 nm or more, it was evaluated as "C" (poor).

[0157] [Table 4]

[0158] As shown in Table 4, Examples 1-1 to 4-1, which used the filler film-forming materials (FM-1 to FM-4) for suppressing semiconductor substrate pattern collapse of the present invention, ensured excellent film thickness uniformity even on substrates with high-aspect-ratio uneven patterns. In contrast, Comparative Examples 3-1, 5-1, and 6-1 did not contain the residual solvent elimination promoter (B-1), and therefore were unable to ensure film thickness uniformity due to sublimation of low-molecular-weight components in the (A) polymer. From these results, it is inferred that the addition of the residual solvent elimination promoter (B-1) contributes to improved film thickness uniformity. Furthermore, Comparative Example 5-1 shows that when the (A) polymer (A-4), which has a small molecular weight and a narrow molecular weight dispersity, was used, the amount of sublimate generated was large, significantly deteriorating film thickness uniformity. In particular, significant deterioration in film thickness uniformity was observed in the evaluation of Substrates A and B, which require thick filler films. From these results, it is inferred that a molecular weight of the (A) polymer of 3,000 or more is preferable to obtain sufficient film thickness uniformity. On the other hand, Comparative Example 8-1, which used Comparative FM-8, showed that when the content of the residual solvent elimination promoter (B-1) exceeded 50 parts by mass per 100 parts by mass of the (A) polymer, sublimates derived from the (B) residual solvent elimination promoter were generated, resulting in a deterioration in film thickness uniformity. This result suggests that there is an optimal amount of the (B) residual solvent elimination promoter, and that in the present invention, 0.1 to 40 parts by mass per 100 parts by mass of the (A) polymer is required, with 15 parts by mass being preferred. Furthermore, Comparative Example 9-1, which used Comparative FM-9 containing the (B) residual solvent elimination promoter additive (B-2) that does not contain a compound represented by general formula (2), presumably failed to ensure film thickness uniformity due to insufficient crosslinking reactivity with the (A) polymer. This result suggests that the (B) residual solvent elimination promoter must contain a compound represented by general formula (2).

[0159] [Fillability] Cross sections of each silicon wafer substrate on which the above-mentioned filling films (FM-1 to FM-4, Comparative FM-3 to FM-11) were formed were cut out, and the filling properties of each filling film were evaluated using a Hitachi electron microscope (S-4700). The filling properties were evaluated as "A" (very good) when the filling film was embedded to the bottom of the pattern, had no cracks, was not deformed such as curvature in the pattern shape, and had no exposed tops. The filling properties were evaluated as "B" (good) when the filling film was embedded to the bottom of the pattern but voids or cracks were observed in the filling film, or when the filling film was embedded to the bottom of the pattern but had deformed such as curvature in the pattern shape. The filling properties were evaluated as "C" (poor) when the filling film was not embedded to the bottom of the pattern and had exposed tops. In Comparative Examples 1-2 to 2-2, no filling films were formed, so the filling properties were not evaluated.

[0160] [Table 5]

[0161] As shown in Table 5, Examples 1-2 to 4-2, which use the filling film-forming material (FM-1 to 4) for suppressing collapse of semiconductor substrate patterns of the present invention, which combines (A) a polymer and (B) a residual solvent removal promoter, are able to ensure excellent filling properties on each semiconductor substrate on which a high aspect ratio uneven pattern is formed.

[0162] In contrast, in Comparative Examples 3-2 and 5-2, which used Comparative FM-3 and Comparative FM-5, which did not contain (B) the residual solvent removal promoter, voids were observed in the filling film. As the aspect ratio of the semiconductor substrate pattern increases, the residual solvent in the filling film filling the recesses becomes more difficult to remove. The heat treatment removes the residual solvent contained in the polymer filling the recesses, but at the same time, the curing of the filling film also progresses, and it is presumed that the residual solvent trapped in the cured film foams, forming voids.

[0163] In contrast, in the filling film forming materials (FM-1 to FM-4) for suppressing collapse of semiconductor substrate patterns of the present invention, the addition of the (B) residual solvent elimination promoter makes it easier for the residual solvent held by the (A) polymer to be eliminated from the filling film, making it possible to form a filling film that does not contain voids. The mechanism by which the residual solvent in the (A) polymer is easily eliminated is presumed to be that the high-dimensional crosslinking between the (A) polymer and the (B) residual solvent elimination promoter compound reduces the affinity between the (A) polymer and the (C) organic solvent, making it easier for the organic solvent to volatilize.

[0164] On the other hand, in Comparative Example 4-2, which used Comparative FM-4 containing an acid generator, voids in the filler film and curvature of the pattern shape were observed. This is presumably due to the fact that when an acid generator is included in the filler film-forming material for suppressing semiconductor substrate pattern collapse, the crosslinking reaction between (A) the polymer and (B) the residual solvent removal promoter accelerates, causing rapid shrinkage of the filler film, which exerts strong physical stress on the semiconductor substrate pattern and results in curvature of the pattern shape. Furthermore, because the curing of the filler film is completed before the removal of the residual solvent is complete, the residual solvent trapped in the cured film foams, forming voids. The problem observed in Comparative Example 8-2, which used Comparative FM-8 containing 50 parts by mass of (B) the residual solvent removal promoter, is also presumably due to the same reason as in Comparative Example 4-2, namely, the accelerated crosslinking reaction caused by the excessive addition of (B) the residual solvent removal promoter. For this reason, the present invention does not contain an acid generator, and the content of (B) the residual solvent removal promoter must be 0.1 to 40 parts by mass, preferably 15 parts by mass, per 100 parts by mass of the polymer.

[0165] Furthermore, when the molecular weight dispersity (Mw / Mn) of the polymer is narrow, as in Comparative FM-6 and Comparative FM-7, the fluidity is poor, and therefore in Comparative Examples 6-2 and 7-2, the filling film does not fill the bottom of the pattern, and the top of the pattern is exposed. From these results, it is preferable that the molecular weight dispersity (Mw / Mn) of the (A) polymer used in the filling film-forming material for suppressing semiconductor substrate pattern collapse is wider in order to improve fluidity, and in the present invention, it must be in the range of 2.50≦Mw / Mn≦9.00.

[0166] In Comparative Example 9-2, in which Comparative FM-9 containing additive (B-2) not containing the compound represented by general formula (2) was used as the (B) residual solvent removal promoter, the removal of the residual solvent from the (A) polymer was insufficient, and voids were confirmed in the filled film. From these results, in the present invention, it is necessary to use (B) a residual solvent removal promoter containing the compound represented by (2).

[0167] In Comparative Example 10-2, cracks were observed at the interface between the semiconductor substrate pattern and the filling film. This is presumably due to the high hydrophobicity of polymer (A-3), which reduced the adhesion between the filling film and the semiconductor substrate pattern due to heat treatment. In contrast, in Example 3-2, by mixing 30 parts by mass of polymer (A-1) with 70 parts by mass of polymer (A-3), adhesion to the semiconductor substrate pattern was improved and excellent filling properties were demonstrated. Polymer (A-3) has low viscosity and excellent filling properties, but its adhesion to the semiconductor substrate deteriorates, so it is preferable to use it in combination with polymer (A-1). In the present invention, a mixing ratio of (A-1) / (A-3) = 30 parts by mass / 70 parts by mass is preferred.

[0168] In Comparative Example 11-2, which uses Comparative FM-11 containing the polymer (A-6) that does not contain the structural unit represented by the general formula (1) of the present invention, the residual solvent content of the polymer is large, so even when using (B) the residual solvent removal promoter, the residual solvent in the polymer is not sufficiently removed, and voids are confirmed in the packed film.From this result, it can be said that in the present invention, the polymer having the structural unit represented by the general formula (1) is necessary.

[0169] [Pattern collapse prevention] The filler film was removed by dry etching (ashing) using a Tokyo Electron Telius etching system. The number of lines remaining on the semiconductor substrate C after removal was determined on the observation screen of the S-4700 electron microscope. The collapse prevention capability of the substrate pattern was evaluated as "A" (very good) when the percentage of lines remaining without collapse was over 90%, "B" (good) when the percentage of lines remaining without collapse was over 70% but not more than 90%, and "C" (poor) when the percentage of lines remaining without collapse was 70% or less. The specific examples of the collapse prevention failure of the substrate pattern are shown in Figure 3. In Comparative Examples 1-3 and 2-3, Comparative FM-1 and Comparative FM-2 were applied, respectively, and the substrates were baked in air at 250°C for 60 seconds, after which the collapse prevention capability of the pattern was evaluated.

[0170] The dry etching (ashing) treatment conditions are as follows: Chamber pressure 2.5Pa RF power 1,000W N2 gas flow rate 500 (mL / min) H2 gas flow rate: 30 (mL / min)

[0171] [Table 6]

[0172] As shown in Table 6, Examples 1-3 to 4-3, which used the filler film-forming materials (FM-1 to FM-4) for suppressing semiconductor substrate pattern collapse of the present invention, were able to ensure excellent pattern collapse suppression even on semiconductor substrates with high-aspect-ratio uneven patterns. In contrast, significant pattern collapse was observed in Comparative Examples 1-3 to 2-3 (semiconductor substrate 8 having a high-aspect-ratio pattern, and cleaning or rinsing liquid 9 (FIG. 3(L)), and semiconductor substrate pattern 8a with pattern collapse after drying (FIG. 3(M))). These results demonstrate that water and 2-propanol, as used in the prior art, are insufficient to suppress collapse of high-aspect-ratio patterns, and that treatment methods using the filler film-forming materials (FM-1 to FM-4) for suppressing semiconductor substrate pattern collapse of the present invention are preferred.

[0173] On the other hand, in the above-mentioned filling property evaluation, pattern collapse was also observed in Comparative Examples 3-3 to 9-3 and 11-3, which were processed using Comparative Examples 3-2 to 9-2 and 11-2, in which voids were observed in the filling film. (Semiconductor substrate 10 having a high aspect ratio pattern and filling film 11 (FIG. 3(N)), hardened filling film 11a containing voids and voids 12 (FIG. 3(O)), and semiconductor substrate pattern 10a with collapsed pattern after removal of filling film containing voids (FIG. 3(P))). From these results, it can be said that the higher the aspect ratio of the pattern, the greater the impact of voids in the filling film on pattern collapse when the filling film is removed. Therefore, it can be said that a filling film forming material for suppressing semiconductor substrate pattern collapse must have the filling performance to reliably fill recesses in the semiconductor substrate pattern.

[0174] In addition, in the above-mentioned filling property evaluation, significant pattern collapse was also observed in Comparative Examples 4-3 and 8-3, which were obtained by processing Comparative Examples 4-2 and 8-2, in which curvature of the pattern shape was observed (semiconductor substrate 13 having a high aspect ratio pattern and filling film 14 (Figure 3(Q)), pattern shape 13a curved due to thermal shrinkage of the filling film and hardened filling film 14a containing voids (Figure 3(R)), semiconductor substrate pattern 13b in which the pattern collapsed after removal of the filling film containing voids (Figure 3(S))), and Comparative Example 10-3, which was obtained by processing Comparative Example 10-2, in which cracks were observed at the interface between the semiconductor substrate pattern and the filling film (semiconductor substrate 15 having a high aspect ratio pattern and filling film 16 (Figure 3(T)), hardened filling film 16a containing cracks and cracks 17 (Figure 3(U)), semiconductor substrate pattern 15a in which the pattern collapsed after removal of the filling film containing cracks (Figure 3(V))). These results show that not only voids during filling, but also defects such as curvature of the pattern shape and cracks at the interface between the filling film and the substrate can cause collapse of the semiconductor substrate pattern after removal of the filling film. In the present invention, by using a filling film-forming material for suppressing collapse of semiconductor substrate patterns that contains (A) a polymer and (B) a residual solvent removal promoter but does not contain an acid generator, it is presumed that defects such as voids in the filling film, curvature of the pattern shape, and cracks at the interface between the filling film and the substrate can be suppressed, and a filling film that is highly effective in suppressing collapse of the semiconductor substrate pattern after removal of the filling film can be formed.

[0175] [Amount of metal impurities on the semiconductor substrate surface after removal of the filling film] Filler film materials for suppressing semiconductor substrate pattern collapse in Examples 1-4 and Comparative Examples 1-4, which have different amounts of metal impurities as listed in Table 7, were applied to the surface of a silicon substrate and baked at 250°C for 60 seconds to form a filler film with a thickness of 3,000 nm. The filler film was then removed by dry etching, and the amount of metal impurities on the silicon substrate surface was evaluated using an Expert VPD-ICP-MS manufactured by IAS Corporation. The metal species evaluated were Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti, and the amount of impurities of these metals was 2.0 x 10E +10 (atoms / cm 2 ) or less is "A" (good), 2.0 x 10E +10 (atoms / cm 2) was evaluated as "B" (poor).

[0176] [Table 7]

[0177] [Table 8]

[0178] As shown in Table 8, the filling film forming material for suppressing collapse of semiconductor substrate patterns of the present invention (Examples 1-4) has a metal impurity content of 3 ppb or less, and therefore the maximum amount of metal impurities on the semiconductor substrate surface after removal of the filling film is 2.0 × 10E +10 (atoms / cm 2 On the other hand, in Comparative Example 1-4, in which the amount of metal impurities exceeds 10 ppb, the amount of metal impurities on the semiconductor substrate surface after the filling film removal was 2.0 × 10E +10 (atoms / cm 2 ) was found to exceed. From these results, in the present invention, in order to reduce the amount of metal impurities on the semiconductor substrate surface after the filler film is removed, it is preferable that the amount of the above-mentioned metal impurities in the filler film forming material for suppressing semiconductor substrate pattern collapse be 3 ppb or less, and by controlling the amount of each metal impurity within the above range, it is possible to prevent a decrease in device yield and reliability. In this evaluation, a filler film with a thickness of 3,000 nm was used so that the amount of metal impurities in the filler film forming material for suppressing semiconductor substrate pattern collapse would affect performance, and these were strict evaluation conditions for evaluating the superiority or inferiority of cleanliness after the filler film is removed.

[0179] A filling film coated with the filling film-forming material for suppressing collapse of semiconductor substrate patterns of the present invention can also be suitably used as a resist underlayer film for semiconductor substrates having a concave-convex pattern formed on their surfaces. Because the heat-treated filling film has excellent solvent resistance, it can be used in various pattern formation methods, such as a multilayer resist process in which a silicon-containing intermediate film (silicon-containing resist intermediate film, inorganic hard mask intermediate film) is formed on the filling film without removing it, and then a conventional organic photoresist film is formed on top of that as a resist upper layer. A circuit pattern formed using a photoresist composition can be transferred by etching to form a semiconductor substrate pattern having a concave-convex pattern coated with the filling film, and then the filling film can be removed by dry etching. The filling film-forming materials for suppressing collapse of semiconductor substrate patterns (FM-1 to 4, Comparative FM-3 to 11) listed in Tables 1 to 3 above were evaluated for solvent resistance, flatness, and pattern formation using the following methods.

[0180] [Solvent resistance] The above-mentioned filling film forming materials for suppressing semiconductor substrate pattern collapse (FM-1 to 4, Comparative FM-3 to 11) were applied to a silicon substrate and baked at 250°C for 60 seconds, after which the film thickness (a [Å]) was measured. PGMEA solvent was dispensed onto the coating, left for 30 seconds, spin-dried, and baked at 100°C for 60 seconds to evaporate the PGMEA, and the film thickness (b [Å]) was measured. The difference in film thickness before and after PGMEA treatment (residual film ratio: (b / a) x 100) was calculated. The results are shown in Table 9 below. In Comparative Examples 1-5 to 2-5, no filling film was formed, so solvent resistance was not evaluated.

[0181] [Table 9]

[0182] As shown in Table 9, the filling film-forming materials (FM-1 to FM-4) for suppressing collapse of semiconductor substrate patterns of the present invention use (A) a polymer having a structural unit represented by the general formula (1) above. Therefore, due to the crosslinking reaction with (B) a residual solvent removal promoter that accompanies heat treatment, the polymer can be increased in molecular weight, resulting in the formation of a filling film with excellent solvent resistance. On the other hand, in Comparative Examples 3-5, 5-5, and 6-5, which used Comparative Examples FM-3, 5, and 6, which did not contain (B) a residual solvent removal promoter, the polymer did not increase in molecular weight sufficiently. Furthermore, in Comparative Example 9-5, which used Comparative Example FM-9, which contained additive (B-2) that did not contain a compound represented by the general formula (2), the crosslinking reactivity with the polymer (A) was reduced, presumably resulting in insufficient solvent resistance.

[0183] [Flatness] Each of the above-mentioned filler film forming materials for preventing collapse of semiconductor substrate patterns (FM-1 to FM-4, comparative FM-3 to FM-11) was applied to a base substrate 18 (SiO2 wafer substrate) with a large isolated trench pattern (Figure 4(W), trench width 10 μm, trench depth 0.10 μm) and baked at 250°C for 60 seconds to form a filler film 19. The step difference between the trench and non-trench portions of the filler film (delta in Figure 4(X)) was then observed using a Park Systems NX10 atomic force microscope (AFM). The results are shown in Table 10. In this evaluation, the smaller the step difference, the better the planarization characteristics. In this evaluation, a 0.10 μm deep trench pattern was planarized using a filler film forming material for preventing collapse of semiconductor substrate patterns with a normal film thickness of approximately 0.2 μm, which provides strict evaluation conditions for evaluating the superiority or inferiority of planarization characteristics. In Comparative Examples 1-6 to 2-6, no filling film was formed, so flatness was not evaluated.

[0184] [Table 10]

[0185] As shown in Table 10, Examples 1-6 to 4-6, which used the filler film-forming materials for suppressing semiconductor substrate pattern collapse (FM-1 to FM-4) of the present invention, showed smaller step differences between the organic film and the trench and non-trench portions, demonstrating superior planarization characteristics, compared to Comparative Examples 3-6 to 11-6, which used the comparative filler film-forming materials for suppressing semiconductor substrate pattern collapse (FM-3 to FM-11). The superior planarization of the filler film-forming materials for suppressing semiconductor substrate pattern collapse of the present invention is presumably due to (A) the broad molecular weight dispersity of the polymer having the structural unit represented by general formula (1), resulting in superior thermal fluidity during application and heat treatment. Furthermore, (B) the residual solvent removal promoter containing the compound represented by general formula (2) is presumably effective in improving fluidity during application due to its small molecular weight and low viscosity. The use of a polymer (A-3) having a structural unit represented by general formula (3) or a high-boiling-point solvent (C-2) can further enhance planarization.

[0186] [Pattern formation test after filling uneven patterns and pattern collapse prevention test after removing the filling film] The above-mentioned filler film-forming materials for suppressing semiconductor substrate pattern collapse (FM-1 to FM-4, comparative FM-3 to FM-11) were applied to the above-mentioned semiconductor substrate C and baked at 250°C for 60 seconds to form the above-mentioned filler film with a thickness of 200 nm as a resist underlayer film. A silicon-containing resist intermediate film was applied thereon and baked at 200°C for 60 seconds to form a 35 nm-thick anti-reflective coating. An ArF single-layer resist of the resist upper layer film material was applied thereon and baked at 105°C for 60 seconds to form a 100 nm-thick photoresist film (resist upper layer film). A line-and-space pattern with an average line width of 30 nm and an average line pitch of 45 nm was formed on the semiconductor substrate C. A circuit pattern formed with the resist upper layer film was transferred to the bulk area where the pattern was not formed to form a new pattern. The pattern transferability of the above-mentioned filler film-forming materials for suppressing semiconductor substrate pattern collapse as a resist underlayer film and the pattern collapse suppression ability after removal of the filler film were evaluated.

[0187] The silicon-containing resist interlayer film was prepared by dissolving the silicon-containing polymer and acid generator PAG1 shown below in an organic solvent containing 0.1 mass% of FC-4430 (manufactured by Sumitomo 3M Limited) in the proportions shown in Table 11, and filtering the resulting solution through a fluororesin filter with a pore size of 0.1 μm. [ka]

[0188] [Table 11] PGEE: Propylene glycol ethyl ether

[0189] The resist polymer, acid generator PAG2, and quencher shown below were dissolved in an organic solvent containing 0.1 mass % of FC-4430 (manufactured by Sumitomo 3M Limited) in the proportions shown in Table 12, and the resulting solution was filtered through a fluororesin filter with a pore size of 0.1 μm to prepare a resist upper layer film material (ArF resist film material).

[0190] [Table 12]

[0191] Resist Polymer Molecular weight (Mw)=7,500 Dispersity (Mw / Mn)=1.9 [ka]

[0192] [ka]

[0193] The film was then exposed using an ArF immersion exposure system (Nikon Corporation; NSR-S610C, NA 1.30, σ 0.98 / 0.65, 35° dipole s-polarized illumination, 6% halftone phase-shift mask), baked at 100°C for 60 seconds (post-exposure bake), and developed in a 2.38% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) for 30 seconds, yielding a 60 nm 1:1 line-and-space pattern.

[0194] Next, the pattern was transferred to the silicon-containing resist intermediate film by dry etching using the resist pattern formed above as a mask using a Telius etching apparatus manufactured by Tokyo Electron Ltd. Similarly, the pattern was transferred to the filling film by dry etching using the silicon-containing resist intermediate film to which the pattern had been transferred as a mask, and the pattern was transferred to the semiconductor substrate C using the filling film to which the pattern had been transferred as a mask.

[0195] The etching conditions are as follows: Transfer conditions for silicon-containing resist interlayer Chamber pressure 7.0Pa RF power 500W CF4 gas flow rate: 150sccm (mL / min) CHF3 gas flow rate: 50sccm (mL / min) Time 15sec

[0196] Transfer conditions to the filling film Chamber pressure 2.0Pa RF power 1,000W N2 gas flow rate: 80sccm (mL / min) CO gas flow rate: 320sccm (mL / min) Time 50sec

[0197] Transfer conditions onto semiconductor substrate C Chamber pressure 10Pa RF power 300W CF4 gas flow rate: 150sccm (mL / min) CHF3 gas flow rate: 30sccm (mL / min) Ar gas flow rate: 50sccm (mL / min) Time 200sec

[0198] Conditions for removing the filling film from semiconductor substrate C Chamber pressure 2.5Pa RF power 1,000W N2 gas flow rate 500 (mL / min) H2 gas flow rate: 30 (mL / min) Time 30sec

[0199] Next, the semiconductor substrate C after removing the filler film was fractured, and the cross section of the pattern was observed using a Hitachi electron microscope (S-4700). The pattern shape of Pattern-B, newly created by transferring the pattern from the resist top layer film, and the pattern collapse suppression of Pattern-A formed on the semiconductor substrate C were evaluated. The collapse suppression of the semiconductor substrate pattern was evaluated as "A" (very good) when the proportion of lines remaining without collapse was over 90%, "B" (good) when the proportion of lines remaining without collapse was over 70% but not more than 90%, and "C" (poor) when the proportion of lines remaining without collapse was 70% or less. The results are shown in Table 13.

[0200] [Table 13]

[0201] The filling film forming materials (FM-1 to FM-4) for suppressing collapse of semiconductor substrate patterns of the present invention not only have excellent solvent resistance, but also excellent filling and flatness, so that the resist upper layer pattern is ultimately transferred well to the bulk portion of the semiconductor substrate C, and a new pattern (Pattern-B) different from the pattern (Pattern-A) originally formed on the semiconductor substrate C can be formed.

[0202] On the other hand, in Comparative Examples 3-7 and 5-7, which used Comparative FM-3 and Comparative FM-5 that did not contain the (B) residual solvent removal promoter, Comparative Example 8-7, which used Comparative FM-8 to which an excessive amount of the (B) residual solvent removal promoter was added, and Comparative Example 9-7, which used Comparative FM-9 that contained additive (B-2) that did not contain the compound represented by general formula (2) as the (B) residual solvent removal promoter, pattern collapse was observed in Pattern-B due to deterioration in film thickness uniformity and flatness.

[0203] On the other hand, in Comparative Example 4-7, which used Comparative FM-4 containing an acid generator, the flatness was significantly impaired due to the curvature of the substrate pattern during heat treatment, and significant pattern collapse was observed. Furthermore, in Comparative Examples 6-7 and 7-7, which used Comparative FM-6 and Comparative FM-7 containing polymer (A-5), which has a narrow molecular weight dispersity (Mw / Mn) and poor fluidity, the filler film did not reach the bottom of the pattern, significantly deteriorating flatness and causing pattern collapse. In Comparative Example 10-7, which used Comparative FM-10 containing polymer (A-3), partial peeling and disappearance of the pattern was observed. This is presumably due to the high hydrophobicity of the polymer and poor adhesion between the filler film and the semiconductor substrate pattern. Furthermore, in Comparative Example 11-1, which used polymer (A-6) not containing a structural unit represented by general formula (1), pattern distortion was observed. This is presumably due to a decrease in crosslink density. The results of suppressing pattern collapse after removal of the filling film in Pattern-A were similar to those of Examples 1-3 to 4-3 and Comparative Examples 1-3 to 11-3.

[0204] From the above, it has become clear that the filling film forming material for suppressing semiconductor substrate pattern collapse of the present invention has good film-forming properties and film thickness uniformity, and is excellent in filling of high aspect ratio patterns, making it extremely useful as a filling film for suppressing pattern collapse in the cleaning and drying processes of fine semiconductor substrate patterns, and that the processing method of the present invention using this material makes it possible to perform processing with extremely low levels of metal impurities on the semiconductor substrate surface after removal of the filling film.In addition, because the above filling film also has excellent solvent resistance and flatness, it is also useful as a resist underlayer film in a multilayer resist process, and can form new fine patterns with high precision on a semiconductor substrate on which a high aspect ratio pattern has been formed.

[0205] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0206] 1...semiconductor substrate on which a pattern is formed, 1a...semiconductor substrate after removal of a filling film, 2...cleaning liquid or rinse liquid, 3...filled film, 3a...hardened filled film, 4...Semiconductor substrate having a high aspect ratio pattern (Pattern-A), 4a...semiconductor substrate pattern (after forming Pattern-B), 5...filling film, 5a...hardened filling film; 5b...filling film pattern; 6...silicon-containing resist intermediate film, 6a...silicon-containing resist intermediate film pattern, 7...resist upper layer film, 7a...circuit pattern, 8...Semiconductor substrate having a high aspect ratio pattern, 8a... Semiconductor substrate pattern collapsed after drying, 9... Cleaning liquid or rinse liquid, 10...Semiconductor substrate having a high aspect ratio pattern, 10a...Semiconductor substrate pattern with collapsed pattern after removal of filling film containing voids, 11...filled film; 11a...hardened filled film containing voids; 12... Void, 13... Semiconductor substrate having a high aspect ratio pattern, 13a...pattern shape curved due to thermal shrinkage of the filling film, 13b...Semiconductor substrate pattern with collapsed pattern after removal of filling film including voids, 14...filled film; 14a...hardened filled film containing voids; 15...Semiconductor substrate having a high aspect ratio pattern, 15a...Substrate pattern with collapsed pattern after removal of filling film containing cracks, 16...Filled film, 16a...Hardened filled film including cracks, 17...crack, 18...underlying substrate having a large isolated trench pattern, 19...filling film, delta...thickness difference between the filling film in the trench part and the non-trench part.

Claims

1. 1. A filling film-forming material for suppressing collapse of a semiconductor substrate pattern, the filling film-forming material comprising: (A) a polymer having a structural unit represented by the following general formula (1); (B) a residual solvent removal promoter containing a compound represented by the following general formula (2); and (C) an organic solvent, wherein the ratio Mw / Mn of the weight average molecular weight Mw of the polymer (A) relative to the number average molecular weight Mn in terms of polystyrene, as determined by gel permeation chromatography, is 2.50≦Mw / Mn≦9.00; the content of the (B) residual solvent removal promoter is 0.1 to 40 parts by mass per 100 parts by mass of the (A) polymer; the filling film-forming material for suppressing collapse of a semiconductor substrate pattern, the filling film-forming material comprising: (A) a polymer having a structural unit represented by the following general formula (1); (B) a residual solvent removal promoter containing a compound represented by the following general formula (2); and (C) an organic solvent, the filling film-forming material comprising: (A) a polymer having a structural unit represented by the following general formula (3) in addition to the structural unit represented by the general formula (1); 【Chemistry 1】 (In the general formula (1), R ０１ is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1. 【Chemistry 2】 (In the general formula (2), Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R ０２ is a hydrogen atom or a methyl group, and q is an integer of 1 to 5. 【Transformation 3】 (In the general formula (3), R ０３ is an unsaturated monovalent organic group having 2 to 30 carbon atoms, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, p is 0 or 1, R ０１ and X are the same as above.)

2. In the general formula (3), R ０３ 2. The filling film forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1, wherein the filling film forming material has any of the structures represented by the following general formula (4): 【Chemistry 4】 (In the general formula (4), * represents a bonding site to an oxygen atom, and R Ａ represents an optionally substituted divalent organic group having 1 to 10 carbon atoms; R Ｂ is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms.

3. 3. The filling film-forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1, wherein the content of the general formula (3) satisfies the relationship a+b=100, b≦90, where a is the proportion of the general formula (1) and b is the proportion of the general formula (3).

4. 3. The filling film forming material for suppressing collapse of semiconductor substrate patterns according to claim 1 or 2, characterized in that the (C) organic solvent contains a high-boiling point solvent, and the high-boiling point solvent is one or more organic solvents having a boiling point of 180°C or higher.

5. 3. The filling film forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1, further comprising (D) a surfactant.

6. 3. The filler film forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1, wherein the amount of metal impurities in the filler film forming material for suppressing collapse of a semiconductor substrate pattern is 3 ppb or less in terms of mass ratio.

7. 7. The filling film forming material for suppressing collapse of semiconductor substrate patterns according to claim 6, wherein the metal is Na, Mg, K, Ca, Mn, Fe, Ni, Cu, or Ti.

8. 3. A method for processing a semiconductor substrate, comprising the steps of: filling a semiconductor substrate having an aspect ratio of 5 or more and a concave-convex pattern formed on its surface with the filling film forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1 or 2 to form a filling film; and removing the filling film.

9. A method for drying a semiconductor substrate having a concave-convex pattern formed on its surface, comprising: (1) a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid, or a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid and then replacing the cleaning liquid with a rinse liquid; (2) A step of replacing the cleaning liquid or the rinsing liquid with the filling film-forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1 or 2, and filling the filling film; (3) a step of hardening the filling film by heat treating it at a temperature of 100° C. or higher and 600° C. or lower for 10 to 600 seconds; (4) removing the hardened filling film from the semiconductor substrate by dry etching; 10. A method for treating a semiconductor substrate, comprising:

10. A method for forming a different concave-convex pattern on a surface of a semiconductor substrate, the method comprising the steps of drying the semiconductor substrate and forming a different concave-convex pattern on the surface of the semiconductor substrate, the method comprising the steps of: (1) a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid, or a step of cleaning the semiconductor substrate on which the pattern has been formed with a cleaning liquid and then replacing the cleaning liquid with a rinse liquid; (2) A step of replacing the cleaning liquid or the rinsing liquid with the filling film-forming material for suppressing collapse of a semiconductor substrate pattern according to claim 1 or 2, and filling the filling film; (3) a step of hardening the filling film by heat treating it at a temperature of 100° C. or higher and 600° C. or lower for 10 to 600 seconds; (4) forming a silicon-containing resist intermediate film on the cured filling film using a silicon-containing resist intermediate film material; (5) forming a resist upper layer film on the silicon-containing resist intermediate film using a photoresist composition; (6) forming a circuit pattern on the resist upper layer film; (7) A step of transferring the pattern to the silicon-containing resist intermediate film by etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (8) A step of transferring a pattern to the hardened filling film by etching using the silicon-containing resist intermediate film to which the pattern has been transferred as a mask; (9) A step of forming a different concave-convex pattern by etching the semiconductor substrate having the concave-convex pattern formed on its surface using the hardened filling film to which the pattern has been transferred as a mask; (10) removing the hardened filling film from the semiconductor substrate by dry etching; 1. A method for processing a semiconductor substrate, comprising:

11. After removing the hardened filling film from the semiconductor substrate, the metal impurities on the surface of the semiconductor substrate are 2.0×10E ＋１０ atoms / cm ２ 10. The method for processing a semiconductor substrate according to claim 9, wherein the following steps are performed:

12. 10. The method for treating a semiconductor substrate according to claim 9, wherein the cleaning liquid or the rinsing liquid is a liquid containing at least one of water, a water-soluble alcohol, and a fluorine compound.

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