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

Abstract

The present invention relates to a filling film forming material for suppressing pattern collapse of a semiconductor substrate and a processing method for a semiconductor substrate. A filling film forming material for suppressing pattern collapse of a semiconductor substrate, characterized by containing (A) a polymer having a structural unit represented by the following general formula (1), (B) a residual solvent separation promoter containing a compound represented by the following general formula (2), and (C) an organic solvent, the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the (A) polymer obtained by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.00, the content of the (B) residual solvent separation promoter is 0.1 to 40 parts by mass with respect to 100 parts by mass of the (A) polymer, and the (B) residual solvent separation promoter does not contain an acid generator.

Description

Technical Field

[0001] This invention relates to a filler film forming material for suppressing pattern collapse on a semiconductor substrate and a method for processing a semiconductor substrate. Existing technology

[0002] In the manufacturing processes of semiconductor devices and microelectromechanical systems (MEMS), liquids are used to process substrates (processed materials). For example, substrates, multilayer films, and resist films are patterned using liquid processing to form fine structures on the substrate. Furthermore, impurities and residues remaining on the substrate are removed by washing with liquid. These steps are often performed in combination. However, when the liquid is removed after processing, the surface tension of the liquid can sometimes cause the fine structures formed on the substrate to collapse.

[0003] On the other hand, in semiconductor devices used in networks and digital home appliances, with the advancement of miniaturization, high integration, and high speed, the substrate pattern is also becoming increasingly refined. If the aspect ratio (the ratio of height to width in the pattern) increases along with this miniaturization, the substrate pattern is prone to collapse during wafer drying due to the gas-liquid interface passing through the pattern. Examples of microstructure patterns that easily cause substrate pattern collapse include line and spacing patterns in Logic's FinFET structure, line and spacing patterns and island patterns in DRAM's STI (ShallowTrench Isolation) structure, pillar patterns in DRAM capacitor structures, and hole and slit patterns in 3D-NAND cell structures. Currently, there is no effective countermeasure to address this problem. Therefore, when facing the miniaturization, high integration, or high speed of semiconductor devices and micromachines, it is necessary to design patterns that do not cause pattern collapse, which sometimes significantly restricts the freedom of pattern design.

[0004] Patent Document 1 discloses a method for suppressing substrate pattern collapse by replacing water with 2-propanol in the cleaning solution before the gas-liquid interface passes through the pattern. However, this method has limitations, such as being able to accommodate patterns with an aspect ratio of 5 or less.

[0005] Patent document 2 discloses a cleaning method that uses oxidation or the like to modify the surface of a wafer with a raised or recessed pattern formed by a silicon-containing film, and uses a water-soluble surfactant or silane coupling agent to form a water-repellent protective film on this surface, thereby reducing capillary forces and preventing the pattern from collapsing.

[0006] Patent document 3 discloses a technique for preventing substrate pattern collapse by using a processing solution containing a silanizing agent and solvent, primarily N,N-dimethylaminotrimethylsilane, to perform hydrophobic treatment.

[0007] Patent document 4 proposes the following method: After cleaning the substrate with the formed embossed pattern with a rinsing solution, the remaining rinsing solution in the recesses of the pattern is replaced by a filling treatment solution containing sublimable substances such as camphor and naphthalene, filling the recesses of the pattern. The sublimable substances are then precipitated from the aforementioned treatment solution, and the precipitated solid sublimable substances are removed by sublimation. However, this method, which uses common sublimable substances, often results in poor filling of the sublimable substances in the recesses of the pattern, and the effect of suppressing pattern collapse on the substrate surface is unsatisfactory.

[0008] Patent Document 5 discloses a technique for forming a filler film and preventing the collapse of the substrate pattern by coating a substrate pattern collapse suppressant containing a compound with aromatic rings and a solvent onto the pattern side of a substrate on one side. Patent Document 6 discloses a technique for forming a filler film and preventing the collapse of the substrate pattern by coating a substrate pattern collapse suppressant containing a vinyl polymer with hydroxyl groups and a solvent. In order to maintain the strength of the substrate pattern by suppressing the thermal melting of the filler film during removal by dry etching or the like, a heat treatment is required. However, the composition of the compound and solvent only contains a large amount of hydrophilic groups. The residual solvent in the compound is not easily removed from the filler film at the bottom of the pattern during heat treatment, and will foam in the filler film to form pores. Therefore, the collapse suppression effect of the high aspect ratio microstructure pattern can not be said to be sufficient.

[0009] Patent Document 7 discloses a composition for forming a lower layer film of a multilayer resist, characterized by containing a specific polymer, a specific crosslinking agent, an acid generator, and a solvent. This composition can form a thick film with excellent preservation stability and crack resistance; however, the combination of the specific polymer and the specific crosslinking agent results in insufficient filling of high aspect ratio patterned substrates. Therefore, a filling film forming material for suppressing pattern collapse with excellent filling performance of high aspect ratio microstructure patterns is sought.

[0010] Existing technical documents

[0011] Patent documents

[0012] [Patent Document 1] Japanese Patent Application Publication No. 2008-198958

[0013] [Patent Document 2] Japanese Patent No. 4403202

[0014] [Patent Document 3] Japanese Patent Application Publication No. 2010-129932

[0015] [Patent Document 4] Japanese Patent Application Publication No. 2013-042093

[0016] [Patent Document 5] International Publication No. 2018 / 074535

[0017] [Patent Document 6] Japanese Patent No. 6718123

[0018] [Patent Document 7] Japanese Patent No. 6550760 Summary of the Invention

[0019] [The problem the invention aims to solve]

[0020] The present invention was made in view of the above circumstances, and its object is to provide a filling film forming material for suppressing pattern collapse of a semiconductor substrate, which can provide a filling film that fills a high aspect ratio microstructure pattern without pores, and a method for processing a semiconductor substrate that can suppress pattern collapse of a semiconductor substrate.

[0021] [Methods for solving problems]

[0022] To address the aforementioned issues, the present invention provides a filler film forming material for suppressing pattern collapse of semiconductor substrates, comprising (A) a polymer having structural units 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 of the weight-average molecular weight Mw to the number-average molecular weight Mn of the aforementioned polymer (A) obtained by gel permeation chromatography, Mw / Mn, is 2.50≤Mw / Mn≤9.00, the content of the aforementioned residual solvent removal promoter (B) is 0.1 to 40 parts by mass relative to 100 parts by mass of the aforementioned polymer (A), and it does not contain an acid-generating agent.

[0023] [Chemistry 1]

[0024]

[0025] In the aforementioned general formula (1), R 01 X is a monovalent organic group with 1 to 30 carbon atoms, either saturated or unsaturated; m is an integer from 0 to 5; n is an integer from 1 to 6; m+n is an integer between 1 and 6; and p is 0 or 1.

[0026] [Chemistry 2]

[0027]

[0028] In the aforementioned general formula (2), Q is a single bond or a q-valent hydrocarbon group with 1 to 20 carbon atoms. 02 It can be a hydrogen atom or a methyl group. q is an integer from 1 to 5.

[0029] If the filler film forming material for suppressing pattern collapse of semiconductor substrates is such a material, then during the heat treatment of the filler film after filling high aspect ratio patterned substrates, the detachment of residual solvent carried by the polymer (A) in the filler film will be promoted by the residual solvent detachment promoter (B), resulting in a pore-free filler film. Therefore, a processing method with good suppression of substrate pattern collapse after filler film removal can be provided. Furthermore, if the filler film forming material for suppressing pattern collapse of semiconductor substrates contains a polymer (A) with such a molecular weight dispersion range, it has high fluidity, thus being effective for filling high aspect ratio patterned substrates. It also has excellent film-forming properties and suppresses the formation of sublimation during heat treatment, thus suppressing device contamination caused by sublimation. Moreover, it is effective in reducing coating defects and residue after filler film removal, making it an excellent filler film forming material for suppressing pattern collapse of semiconductor substrates. Furthermore, when the filler film filled with the substrate pattern is heat-treated, the cross-linking reaction between (A) polymer and (B) residual solvent removal promoter will proceed gently, and the removal of residual solvent carried by (A) polymer in the filler film will be promoted by (B) residual solvent removal promoter, thus forming a non-porous filler film.

[0030] Furthermore, in this invention, the aforementioned polymer (A) preferably has structural units represented by the following general formula (3) in addition to having the structural units of the aforementioned general formula (1).

[0031] [Chemistry 3]

[0032]

[0033] In the aforementioned general formula (3), R 03 It is a monovalent organic group, saturated or unsaturated, with 1 to 30 carbon atoms; m is an integer from 0 to 5; n is an integer from 1 to 6; m+n is an integer greater than 1 and less than 6; p is 0 or 1; R 01 Synonymous with X and the aforementioned.

[0034] If the filling film forming material for suppressing pattern collapse of semiconductor substrates contains polymers of the above general formula (3), the fluidity increases, making it more effective for filling high aspect ratio patterned substrates. Furthermore, it has low affinity for polar solvents, thus effectively reducing the amount of residual solvent in the filling film.

[0035] Furthermore, in this invention, in the aforementioned general formula (3), R 03 It is preferred to be an alkyl group having 1 to 30 carbon atoms, or any of the structures represented by the following general formula (4).

[0036] [Chemistry 4]

[0037]

[0038] In the above general formula (4), * represents the bonding site to the oxygen atom, R A R is a divalent organic group with 1 to 10 carbon atoms that can also be substituted. B It is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms that can be substituted.

[0039] If the filler film forming material for suppressing pattern collapse of semiconductor substrates contains such a polymer (A), its fluidity is further improved, making it more effective for filling high aspect ratio patterned substrates. It also has low affinity for polar solvents, thus effectively reducing the amount of residual solvent in the filler film. Furthermore, its crosslinking reactivity is increased, resulting in excellent film-forming properties and solvent resistance. It also suppresses the formation of sublimations during heat treatment, thus preventing device contamination caused by sublimations. It is effective in reducing coating defects and residue after filler film removal, making it an even superior filler film forming material for suppressing pattern collapse of semiconductor substrates.

[0040] Furthermore, in this invention, when the ratio of the aforementioned general formula (1) is a and the ratio of the aforementioned general formula (3) is b, it is preferable that the content of the aforementioned general formula (3) conforms to the relationship of a+b=100 and b≤90.

[0041] If the filling film forming material for suppressing semiconductor substrate pattern collapse contains such a polymer (A), it can suppress the deterioration of the adhesion between the filling film and the substrate pattern and reduce the occurrence of cracks in the filling film. Furthermore, when the cleaning solution held in the recess is replaced, the affinity increases, so it is effective for filling high aspect ratio patterned substrates.

[0042] Furthermore, in this invention, the aforementioned organic solvent (C) preferably contains a high-boiling-point solvent.

[0043] If the organic solvent is such (C), the film-forming properties, filling properties, and other properties can be finely adjusted to meet customer requirements, making it more ideal for practical use.

[0044] Furthermore, in this invention, it is preferable that the aforementioned high-boiling-point solvent is one or more organic solvents with a boiling point of 180°C or higher.

[0045] If such a filling film forming material is used to suppress pattern collapse on semiconductor substrates, its fluidity increases, making it more effective for filling high aspect ratio patterned substrates.

[0046] Furthermore, in this invention, the filler film forming material used to suppress the collapse of semiconductor substrate patterns preferably contains more (D) surfactant.

[0047] If it is a filler film forming material used to suppress the collapse of semiconductor substrate patterns, then the film forming properties, filling properties, and other properties can be finely adjusted to meet customer requirements, making it more ideal for practical use.

[0048] Furthermore, in this invention, the amount of metal impurities in the filler film forming material used to suppress pattern collapse of semiconductor substrates is preferably 3 ppb or less by mass ratio.

[0049] Furthermore, in this invention, the aforementioned metals are preferably Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti.

[0050] Thus, by using the filler film forming material for suppressing semiconductor substrate pattern collapse as described above, the amount of metal impurities on the substrate surface after the filler film has been removed from the substrate pattern can be reduced.

[0051] Furthermore, the present invention provides a method for processing a semiconductor substrate, comprising the following steps: filling a semiconductor substrate with an aspect ratio of 5 or more on the surface of which a raised or recessed pattern has been formed using the aforementioned filling film forming material for suppressing semiconductor substrate pattern collapse, and forming a filling film; and removing the aforementioned filling film.

[0052] Thus, the substrate pattern collapse suppression filling film forming material of the present invention is suitable for use as a filling film for a substrate with an aspect ratio of 5 or more on a substrate on which an uneven pattern has been formed on the surface. The substrate pattern collapse suppression performance after the filling film is removed is excellent, so it is suitable for use in substrate pattern collapse suppression treatment to suppress collapse and collapse that occurs when the washing liquid or rinsing liquid is dried after the substrate pattern is washed.

[0053] Furthermore, this invention provides a method for processing a semiconductor substrate, which involves drying a semiconductor substrate whose surface has been patterned with raised and recessed designs.

[0054] The aforementioned semiconductor substrate is dried by including the following steps.

[0055] (1) The step of cleaning the patterned semiconductor substrate with a cleaning solution, or the step of cleaning the patterned semiconductor substrate with a cleaning solution and then replacing it with a rinsing solution.

[0056] (2) The step of replacing the aforementioned cleaning solution or rinsing solution with the filler film forming material for suppressing semiconductor substrate pattern collapse as described above, and filling the filler film thereon.

[0057] (3) The step of hardening the aforementioned filler film by heat treatment at a temperature between 100°C and 600°C for 10 to 600 seconds.

[0058] (4) The step of removing the hardened filler film from the semiconductor substrate by dry etching.

[0059] Thus, the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention is suitable for use as a filler film for a substrate with an uneven pattern already formed on its surface. The substrate pattern collapse suppression performance after the filler film is removed is excellent, so it is suitable for use in semiconductor substrate pattern collapse suppression treatment to suppress collapse and collapse that occurs when the cleaning solution or rinsing solution is dried after the substrate pattern is cleaned.

[0060] Furthermore, this invention provides a method for processing a semiconductor substrate.

[0061] A method for processing a semiconductor substrate,

[0062] This method involves drying a semiconductor substrate with an existing raised and recessed pattern on its surface while simultaneously performing a process to form a raised and recessed pattern on the semiconductor substrate that differs from the original raised and recessed pattern.

[0063] Includes the following steps:

[0064] (1) The step of cleaning the patterned semiconductor substrate with a cleaning solution, or the step of cleaning the patterned semiconductor substrate with a cleaning solution and then replacing it with a rinsing solution.

[0065] (2) The step of using the filling film forming material for suppressing semiconductor substrate pattern collapse as described above to replace the aforementioned cleaning solution or rinsing solution and filling the filling film.

[0066] (3) The step of hardening the filler film by heat treatment at a temperature between 100°C and 600°C for 10 to 600 seconds.

[0067] (4) The step of forming a silicon-containing photoresist interlayer film by using a silicon-containing photoresist interlayer film material on the hardened filler film.

[0068] (5) The step of forming an upper resist film on the silicon-containing photoresist intermediate film using a photoresist composition.

[0069] (6) The step of forming a circuit pattern on the upper layer of the resist film.

[0070] (7) Using the upper resist film with the formed circuit pattern as a mask, the step of etching to transfer the pattern to the intermediate silicon resist film.

[0071] (8) Using the silicon-containing resist intermediate film with the transferred pattern as a mask, the step of etching to transfer the pattern to the hardened filler film.

[0072] (9) Using the hardened filler film with the transferred pattern as a mask, etching a semiconductor substrate on which a raised and recessed pattern has been formed to form a raised and recessed pattern different from the original raised and recessed pattern.

[0073] (10) The step of removing the hardened filler film from the semiconductor substrate by dry etching.

[0074] Thus, the filler film forming material for suppressing pattern collapse of semiconductor substrates of the present invention can fill substrates with surface patterns that have been formed with concave and convex designs, and can also be ideally used as a resist underlayer for multilayer resist processing. Therefore, the steps of removing the coated filler film after substrate cleaning and the coating step of the resist underlayer for multilayer resist processing can be omitted, contributing to the rationalization of semiconductor manufacturing processes. Alternatively, by replacing the drying step of the filler film forming material for suppressing pattern collapse of semiconductor substrates, such as a drying method using 2-propanol, with the filler film forming material for suppressing pattern collapse of semiconductor substrates of the present invention, the coating step of the resist underlayer for multilayer resist processing can be omitted, contributing to the rationalization of semiconductor processing.

[0075] Furthermore, in this invention, the metal impurities on the surface of the semiconductor substrate after the hardened filler film has been removed from the aforementioned semiconductor substrate are 2.0 × 10E. +10 atoms / cm 2 The following is better.

[0076] Thus, the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention contains less metal impurities, resulting in less metal impurities on the substrate surface after the filler film is removed from the substrate pattern. Therefore, there is less concern about a decrease in device yield and reliability, making it suitable for semiconductor substrate pattern collapse suppression treatment that prevents collapse and breakage that occurs when the cleaning solution is dried after substrate pattern cleaning.

[0077] Furthermore, in this invention, the aforementioned cleaning solution or rinsing solution is preferably a liquid containing one or more of water, water-soluble alcohol, and fluorine compounds.

[0078] By selecting such a cleaning or rinsing solution, high affinity between filler film forming materials used for semiconductor substrate pattern collapse can be ensured and suppressed, enabling efficient replacement.

[0079] [The effects of the invention]

[0080] As explained above, the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention and the semiconductor substrate processing method using the above material have high fillability for patterned substrates with high aspect ratios, thus exhibiting excellent suppression of substrate pattern collapse after the filler film is removed. It can be widely used in, for example, fine structural patterns prone to substrate pattern collapse, such as: line and spacing patterns of FinFET structures in Logic, line and spacing patterns of STI structures in DRAM, island patterns, pillar patterns of capacitor structures in DRAM, and hole patterns and slit patterns in cell structures of 3D-NAND. Furthermore, the surface of the semiconductor substrate after the filler film is removed has less metallic impurities, making it extremely useful for substrate cleaning and drying processes. Therefore, with the increasing miniaturization and high aspect ratio of semiconductor substrate patterns in the future, it is believed that its application will be more widespread in semiconductor substrate pattern collapse suppression processes that occur during the drying of cleaning or rinsing solutions after substrate pattern cleaning. The filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention and the semiconductor substrate processing method using the above material can be ideally used in these applications. Attached Figure Description

[0081] Figure 1 Figures (A) through (D) show an example of a method for processing a semiconductor substrate using the filler film forming material for suppressing semiconductor substrate pattern collapse according to the present invention.

[0082] Figure 2 Figures (E) to (M) show an illustration of another example of a method for processing a semiconductor substrate pattern using the filler film forming material for suppressing semiconductor substrate pattern collapse according to the present invention.

[0083] Figure 3 Figures (L) to (V) show an example of poor suppression of semiconductor substrate pattern collapse that causes substrate pattern collapse, compared to embodiments of the present invention.

[0084] Figure 4 (W) and (X) show an explanatory diagram of the flatness evaluation method of an embodiment of the present invention. Detailed Implementation

[0085] As mentioned above, with the miniaturization of semiconductor devices, there is a need for a filler film forming material for suppressing the collapse of semiconductor substrate patterns after the substrate is cleaned, which has high fillability for high aspect ratio patterned substrates and excellent suppression of the collapse of the substrate pattern after the filler film is removed, and a method for processing semiconductor substrates using such a material.

[0086] The inventors of this application have made efforts to explore the above-mentioned problems, and as a result, verified the effect of suppressing the collapse of the substrate pattern caused by the formation of the filler film in the collapse suppression treatment of the high aspect ratio patterned substrate after substrate cleaning. They also discovered that in order to eliminate the pores in the filler film that cause the collapse of the substrate pattern, a filler film forming material for suppressing the collapse of semiconductor substrate patterns, which is mainly composed of a polymer with a specific structure and a residual solvent removal promoter, and a semiconductor substrate processing method using this material are very effective. Thus, the present invention was completed.

[0087] That is, the present invention is a filler film forming material for suppressing pattern collapse of semiconductor substrates, comprising (A) a polymer having structural units represented by the following general formula (1), (B) a residual solvent removal promoter containing compounds represented by the following general formula (2), and (C) an organic solvent, wherein the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of the aforementioned polymer (A) obtained by gel permeation chromatography is 2.50≤Mw / Mn≤9.00, the content of the aforementioned residual solvent removal promoter (B) is 0.1 to 40 parts by mass relative to 100 parts by mass of the aforementioned polymer (A), and it does not contain an acid generating agent.

[0088] [Chemistry 5]

[0089]

[0090] In the aforementioned general formula (1), R 01 X is a monovalent organic group with 1 to 30 carbon atoms, either saturated or unsaturated; m is an integer from 0 to 5; n is an integer from 1 to 6; m+n is an integer between 1 and 6; and p is 0 or 1.

[0091] [Chemistry 6]

[0092]

[0093] In the aforementioned general formula (2), Q is a single bond or a q-valent hydrocarbon group with 1 to 20 carbon atoms. 02 It can be a hydrogen atom or a methyl group. q is an integer from 1 to 5.

[0094] The following description pertains to embodiments of the present invention, but the present invention is not limited to these embodiments. That is, it should be understood that appropriate modifications or improvements made to the following embodiments based on ordinary knowledge of those skilled in the art also fall within the scope of the invention.

[0095] <Fill film forming material for suppressing pattern collapse on semiconductor substrates>

[0096] The filler film forming material for suppressing pattern collapse of semiconductor substrates of the present invention comprises (A) a polymer having structural units represented by the above-described general formula (1), (B) a residual solvent removal promoter containing a compound represented by the above-described general formula (2), and (C) an organic solvent. The ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polymer (A) obtained by gel permeation chromatography, Mw / Mn, is 2.50 ≤ Mw / Mn ≤ 9.00. The content of the residual solvent removal promoter (B) is 0.1 to 40 parts by mass relative to 100 parts by mass of the polymer (A), and it does not contain an acid-generating agent. This filler film forming material for suppressing pattern collapse of semiconductor substrates is suitable for use in a process where, after a cleaning step and before a drying step, a cleaning solution or rinsing solution held in a recess is used to fill the recess, and the formed filler film is removed by dry etching.

[0097] The filling film forming material for suppressing pattern collapse of semiconductor substrates can be used to fill gaps in the substrate pattern. Specifically, after cleaning a substrate with an uneven pattern formed on its surface, the filling film forming material for suppressing pattern collapse of semiconductor substrates is applied to the uneven pattern side of the substrate. As a result, the cleaning solution, rinsing solution, and other liquids on the substrate are replaced by the filling film forming material for suppressing pattern collapse of semiconductor substrates, forming a film (filling film) that fills the gaps in the uneven pattern. In this way, the liquids such as cleaning solutions and rinsing solutions can be removed without drying them, so pattern collapse caused by the gas-liquid interface passing through the side of the substrate pattern can be suppressed. This filling film can be removed from the substrate by dry etching or the like, if necessary.

[0098] The filler film forming material for suppressing semiconductor substrate pattern collapse contains (A) a polymer, (B) a residual solvent removal promoter, and (C) a solvent, but does not contain an acid-generating agent, and is able to form a filler film with excellent suppression of substrate pattern collapse. The reason why the filler film forming material for suppressing semiconductor substrate pattern collapse achieves the above-mentioned effect by having the above-described structure is not entirely clear, but the reasons can be speculated as follows.

[0099] That is, the filling film forming material for suppressing semiconductor substrate pattern collapse uses a polymer (A) having the structural unit represented by the above general formula (1). Therefore, due to the crosslinking reaction accompanied by heat treatment and (B) residual solvent removal accelerator, the molecular weight can be increased, which results in heat resistance for the filling film. Such a substrate pattern collapse suppressing filling film, even when partially or entirely heated during removal from the substrate by dry etching or the like, will still suppress thermal melting and easily maintain strength, thus suppressing substrate pattern collapse and reliably removing it by dry etching or the like. On the other hand, if the aspect ratio of the substrate pattern increases, the residual solvent in the filling film filling the recesses becomes difficult to remove. Due to heat treatment, the residual solvent carried by the polymer (A) that has filled the recesses will gradually dissipate, but the hardening of the filling film will also occur at the same time, so the residual solvent trapped in the hardened film will bubble and easily form pores. In previous International Patent Publication No. 2018 / 074535, when a composition containing only a known specific polymer and solvent was filled into a high aspect ratio patterned substrate, bubbling of residual solvent from the specific polymer occurred, resulting in pores in the filled film.

[0100] In contrast, the filling film forming material for suppressing pattern collapse of semiconductor substrates according to the present invention, by adding a residual solvent detachment promoter (B), makes it easier for the residual solvent held by the polymer (A) to detach from the filling film, thus forming a pore-free filling film. The mechanism by which the residual solvent in the polymer (A) becomes easier to detach is presumably that the compound of the polymer (A) and the residual solvent detachment promoter (B) is cross-linked in a high dimension, reducing the affinity between the polymer (A) and the solvent (C), making the solvent (C) more volatile. On the other hand, the prior art Japanese Patent No. 6550760 is characterized by a composition containing a known specific polymer, a specific cross-linking agent, an acid product, and a solvent. The residual solvent detachment of the aforementioned specific polymer is insufficient, and pores easily appear in the filling film of high aspect ratio patterned substrates. Therefore, the structure of the polymer is preferably that of the polymer of the present invention having the structural unit represented by the above general formula (1).

[0101] Furthermore, if the filler film forming material used to suppress semiconductor substrate pattern collapse contains an acid-generating agent, the catalytic effect of the generated acid will accelerate the crosslinking reaction between the polymer (A) and the residual solvent removal accelerator (B). The resulting rapid shrinkage of the filler film leads to strong physical stress on the substrate pattern, making it prone to bending. Moreover, the hardening of the filler film is completed before the residual solvent removal is finished, causing the residual solvent trapped in the hardened film to bubble and easily form pores. The filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention does not contain an acid-generating agent, so the crosslinking reaction between the polymer (A) and the residual solvent removal accelerator (B) proceeds gently. This promotes the removal of the residual solvent and suppresses stress on the substrate pattern, thus maintaining strength. Therefore, it provides a filler film forming material for suppressing semiconductor substrate pattern collapse with excellent filling properties.

[0102] This filler film forming material for suppressing semiconductor substrate pattern collapse can achieve a coating thickness ranging from a lower limit of 50 nm to an upper limit of 6000 nm by adjusting the solid component concentration of the filler film forming material. It is useful as a filler film for various microstructures prone to substrate pattern collapse. Examples of microstructures prone to substrate pattern collapse include: line and spacing patterns of FinFET structures in Logic, line and spacing patterns and island patterns of STI structures in DRAM, pillar patterns of capacitor structures in DRAM, and hole patterns and slit patterns of cell structures in 3D-NAND.

[0103] [(A) Polymer]

[0104] The (A) polymer contained in the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention has a structural unit represented by the following general formula (1).

[0105] [Chemistry 7]

[0106]

[0107] In the aforementioned general formula (1), R 01 X is a monovalent organic group with 1 to 30 carbon atoms, either saturated or unsaturated; m is an integer from 0 to 5; n is an integer from 1 to 6; m+n is an integer between 1 and 6; and p is 0 or 1.

[0108] By using polymers having structural units represented by the above general formula (1), a filler film forming material for suppressing semiconductor substrate pattern collapse can be provided, which has excellent substitution affinity, flowability, and affinity to the substrate for cleaning or rinsing solutions.

[0109] In the above general formula (1), R 01The term refers to monovalent organic groups with 1 to 30 carbon atoms, whether saturated or unsaturated, such as: saturated hydrocarbon groups with monovalent valence, including methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, etc.; unsaturated chain hydrocarbon groups with monovalent valence, including vinyl, propynyl, butenyl, pentenyl, ethynyl, propynyl, etc.; monocyclic saturated cyclic hydrocarbon groups with monovalent valence, including cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc.; monocyclic unsaturated cyclic hydrocarbon groups with monovalent valence, including cyclobutenyl, cyclopentenyl, cyclohexenyl, etc.; polycyclic cyclic hydrocarbon groups with monovalent valence, including norbornel, adamantyl, etc.; and aromatic hydrocarbon groups with monovalent valence, including phenyl, methylphenyl, naphthyl, methylnaphthyl, anthracene, methylanthrayl, etc.

[0110] The above R 01 The organic groups represented can be listed as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, n-hexyloxy, etc., and alkoxy groups such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, n-pentoxycarbonyl, n-hexyloxycarbonyl, etc.

[0111] The hydrogen atoms in the aforementioned saturated hydrocarbon groups, unsaturated chain hydrocarbon groups, monocyclic saturated cyclic hydrocarbon groups, monocyclic unsaturated cyclic hydrocarbon groups, polycyclic cyclic hydrocarbon groups, aromatic hydrocarbon groups, alkoxy groups, and alkoxy carbonyl groups can be partially or completely replaced. Substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms, hydroxyl, cyano, carboxyl, nitro, amino, alkoxy, alkoxy carbonyl, acyl, alkoxy carbonyloxy, aryl, lactone, and other aliphatic heterocyclic groups, furanyl, pyridyl, and other aromatic heterocyclic groups.

[0112] Regarding the above R 01 The organic group represented is preferably methyl, considering the availability of raw materials.

[0113] In the above general formula (1), X represents a divalent organic group with 1 to 30 carbon atoms, such as: methylene, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octanediyl, decanediyl, etc., monocyclic cycloalkyldiyl, cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, cyclodecanediyl, methylcyclohexanediyl, ethylcyclohexanediyl, etc., bicyclic [2.2.1]heptanediyl, bicyclic [2.2.2]octanediyl, tricyclic [5.2.1.0]... 2,6 ] Decanediyl (dicyclopentylene), tricyclic [3.3.1.1] 3,7 ] Decanediyl, tetracyclo[6.2.1.1 3,6 .0 2,7Polycyclic cycloalkanes such as dodecanediyl and adamantanediyl, aromatic dimethyl compounds such as phenylene and naphthylene, etc.

[0114] The alkanedioxy group represented by X above includes, for example, groups formed by combining an alkanediol with an oxygen atom. Furthermore, the cycloalkanedioxy group represented by X above can include groups formed by combining a cycloalkanediol with an oxygen atom.

[0115] Some or all of the hydrogen atoms in the aforementioned alkyldiyl, cycloalkyldiyl, alkyldioxy, cycloalkyldioxy, and arenediyl groups can be substituted, for example, with the aforementioned R groups. 01 Examples of substituents that the organic group may represent include the same group, etc.

[0116] The organic groups represented by X above can include groups represented by the following formulas.

[0117] [Chemistry 8]

[0118]

[0119] In the above formula, * represents an atomic bond.

[0120] Regarding X above, considering the source of raw materials, it would be preferable to list methylene.

[0121] For polymers having structural units represented by the above general formula (1), the following examples can be specifically listed, but are not limited to these. From the viewpoint of raw material availability, (AX-1) or (AX-3) is more ideal, especially (AX-3).

[0122] [Chemistry 9]

[0123]

[0124] The ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polymer (A) obtained by gel permeation chromatography is preferably 2.50≤Mw / Mn≤9.00 and 3.00≤Mw / Mn≤8.00.

[0125] If the Mw / Mn ratio of the polymer used in the filling film forming material for suppressing semiconductor substrate pattern collapse is outside such a range, the fluidity of the filling film will be reduced, and even when combined with the residual solvent desorption accelerator (B), it will still be impossible to provide a filling film forming material for suppressing semiconductor substrate pattern collapse with excellent filling properties.

[0126] The weight-average molecular weight (Mw) of the polymer (A) obtained by gel permeation chromatography is preferably 1,500≤Mw≤20,000, more preferably 3,000≤Mw≤15,000, and especially preferably 4,000≤Mw≤9,000.

[0127] By controlling the Mw of the polymer (A) used in the filler film forming material for suppressing semiconductor substrate pattern collapse within such a range, the flowability of the filler film can be improved. Combined with the residual solvent removal promoter (B), a filler film forming material for suppressing semiconductor substrate pattern collapse with excellent filling properties can be provided. Furthermore, a filler film with excellent film thickness uniformity and low sublimation content can be formed.

[0128] The polymer (A) mentioned above may also contain polymers having structural units of the above formula (1) and further having structural units represented by the following general formula (3).

[0129] [Chemistry 10]

[0130]

[0131] In the aforementioned general formula (3), R 03 It is a monovalent organic group, saturated or unsaturated, with 1 to 30 carbon atoms; m is an integer from 0 to 5; n is an integer from 1 to 6; m+n is an integer greater than 1 and less than 6; p is 0 or 1; R 01 Synonymous with X and the aforementioned.

[0132] In general formula (3), R 03 A monovalent organic group, either saturated or unsaturated, with 1 to 30 carbon atoms, such as R 01 The same applies.

[0133] Furthermore, the ideal form of the above general formula (3) can be enumerated by having R 03 Polymers whose structural units are alkyl groups having 1 to 30 carbon atoms, or any of the structures represented by the following general formula (4).

[0134] [Chemistry 11]

[0135]

[0136] In the aforementioned general formula (4), * represents the bonding site to the oxygen atom, R A R is a divalent organic group with 1 to 10 carbon atoms that can also be substituted. B It is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms that can be substituted.

[0137] In the above general formula (4), R AIt represents divalent organic groups with 1 to 10 carbon atoms, such as methylene, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octanediyl, decanediyl, etc., alkyldiyl, phenyldiyl, methylphenyldiyl, naphthyl, etc., aromatic diyl, etc.

[0138] In the above general formula (4), R B It represents a monovalent organic group with 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, etc., alkyl, phenyl, tolyl, xylyl, mesitylene, naphthyl, etc., aryl, etc.

[0139] Some or all of the hydrogen atoms in the aforementioned alkyl dienes, aromatic dienes, alkyl groups, aryl groups, etc., can be substituted. Examples of substituents include R mentioned above. 01 Examples of substituents that the organic group may represent include the same group, etc.

[0140] Ideal examples can be illustrated by the following structure. With such a structure, flowability is improved, filling properties are enhanced, and a filling film forming material for suppressing semiconductor substrate pattern collapse can be provided, capable of forming a filling film with low residual solvent content. Furthermore, heat resistance and film-forming properties are improved, the occurrence of sublimation during heat curing is suppressed, device contamination caused by sublimation is suppressed, and coating defects are suppressed.

[0141] [Chemistry 12]

[0142]

[0143] In the above formula, * represents the bonding site to the oxygen atom.

[0144] Polymers having structural units represented by the above general formula (3) can be specifically listed below, but are not limited to these. From the viewpoint of raw material availability, (AY-1) or (AY-3) is more ideal, especially (AY-3).

[0145] [Chemistry 13]

[0146]

[0147] For the content of polymers with structural units of general formula (3), when the ratio of the aforementioned general formula (1) is a and the ratio of the aforementioned general formula (3) is b, it is preferable to satisfy the relationship of a+b=100 and b≤90, and even better to satisfy the relationship of b≤70.

[0148] By controlling the proportion of the polymer in general formula (3) within such a range, the affinity with the cleaning solution or rinsing solution can be ensured, and the filling performance for the patterned substrate can be improved. Furthermore, the occurrence of cracks in the filler film, which is caused by insufficient adhesion between the patterned substrate and the filler film, can be reduced.

[0149] Furthermore, as mentioned above, not only can two polymers be mixed in a desired ratio, but equivalent compositions can also be achieved by controlling the proportion of substituents in one polymer. In this case, the composition of R can be controlled by using the polymer represented by the following general formula (5). 04 The proportions of the structure are used to prepare it. Specifically, when the structure constituting R 04 When the proportion of hydrogen atoms in the structure is a, and the proportion of alkyl groups with 1 to 10 carbon atoms or the structure represented by the above general formula (4) is b, the relationship a+b=100 is satisfied. In this case, the proportions that satisfy b≤90 are better, and the ratios that satisfy b≤70 are even better.

[0150] [Chemistry 14]

[0151]

[0152] In the above general formula (5), R 04 The above-mentioned R is composed of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or any of the structures represented by the above general formula (4). 04 In the structure, when the proportion of hydrogen atoms is a and the proportion of alkyl groups with 1 to 10 carbon atoms or the structure represented by the above general formula (4) is b, the relationship a + b = 100 is satisfied. m, n, m + n, p, R 01 X and the aforementioned are the same.

[0153] In the filler film forming material used to suppress pattern collapse of semiconductor substrates, the lower limit of the content of polymer (A) is 0.1% by mass, more preferably 3% by mass, and even more preferably 5% by mass. On the other hand, the upper limit of the above content is 50% by mass, more preferably 40% by mass, and even more preferably 35% by mass.

[0154] (A) By ensuring the polymer content falls within the aforementioned range, the coating thickness of the filler film forming material used to suppress semiconductor substrate pattern collapse can be formed within a lower limit of 50 nm and an upper limit of 6000 nm. Therefore, filler films are useful for various microstructures prone to substrate pattern collapse. Examples of microstructures prone to substrate pattern collapse include: line and spacing patterns of FinFET structures in Logic, line and spacing patterns and island patterns of STI structures in DRAM, pillar patterns of capacitor structures in DRAM, hole patterns and slit patterns of cell structures in 3D-NAND, etc.

[0155] The amount of metallic impurities in the polymer (A) above is preferably below 100 ppb by mass, even better below 10 ppb, and ideally below 5 ppb.

[0156] The aforementioned 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, with Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti being even more preferred. Metal impurities of the above elements are considered in the form of metal particles, ions, colloids, complexes, oxides, and nitrides, regardless of whether they are dissolved or undissolved, and are present in the polymer.

[0157] By controlling the various metal impurities within the above-mentioned range, the amount of metal impurities on the substrate surface after the filler film filling the embossed pattern is removed by dry etching can be reduced, thus preventing a decrease in device yield and reliability.

[0158] The types and contents of metals in the above polymers can be determined using methods such as ICP-MS (Inductively Coupled Plasma-Mass Spectrometry).

[0159] [(B) Residual solvent removal accelerator]

[0160] (B) The residual solvent removal accelerator contains a compound represented by the following general formula (2). This allows it to crosslink with the polymer (A) in the filler film, facilitating the removal of residual solvent held by the polymer (A) from the filler film and forming a pore-free filler film. Furthermore, if the compound is represented by the following general formula (2), it has a sufficient crosslinking speed; therefore, this invention does not contain an acid-generating agent. Here, "acid-generating agent" refers to an additive that generates acid due to heat or light, such as sulfonium salts, monazite salts, or onium salt compounds. When an acid-generating agent is present, the crosslinking reaction between the polymer (A) and the residual solvent removal accelerator (B) is accelerated due to the catalytic effect of the acid, causing the filler film to shrink rapidly. This results in strong physical stress on the substrate pattern, potentially causing the substrate pattern to bend. Furthermore, the hardening of the filler film is completed before the residual solvent removal is finished, thus potentially causing residual solvent trapped in the hardened film to bubble and form pores.

[0161] [Chemistry 15]

[0162]

[0163] In the aforementioned general formula (2), Q is a single bond or a q-valent hydrocarbon group with 1 to 20 carbon atoms. 02 It can be a hydrogen atom or a methyl group. q is an integer from 1 to 5.

[0164] In the above general formula (2), Q is a single bond or a q-valent hydrocarbon group with 1 to 20 carbon atoms. q is an integer from 1 to 5, preferably 2 or 3. When Q is a q-valent hydrocarbon group with 1 to 20 carbon atoms, Q is a q-valent hydrocarbon group from which q hydrogens have been removed from a hydrocarbon with 1 to 20 carbon atoms. In this case, hydrocarbons with 1 to 20 carbon atoms can be more specifically listed as methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane.

[0165] In the above general formula (2), R 02 It can be a hydrogen atom or a methyl group, preferably a methyl group.

[0166] Examples of compounds represented by the above general formula (2) include, but are not limited to, the following compounds. In the following formula, R... 02 Same as above. It satisfies q = 3 and R 02 When the methyl group is used, it is more ideal from the perspectives of improving curability, film thickness uniformity, and residual solvent removal, especially the hexamethoxymethylated forms of triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene.

[0167] [Chemistry 16]

[0168]

[0169] [Chemistry 17]

[0170]

[0171] The aforementioned residual solvent removal accelerator (B) can be used alone or in combination of two or more. The content of the residual solvent removal accelerator (B) is preferably 0.1% to 40% by mass, or 10% to 30% by mass, relative to 100 parts by mass of the aforementioned polymer (A). If the addition amount is less than 0.1% by mass, it will not have sufficient cross-linking reactivity with the polymer (A), and will not be able to promote the removal of residual solvent carried by the polymer (A) in the filled film. On the other hand, if the addition amount exceeds 40% by mass, the cross-linking reaction between the polymer (A) and the residual solvent removal accelerator (B) will be deactivated, resulting in the formation of sublimation and deterioration of film thickness uniformity.

[0172] [(C) Organic solvent]

[0173] The filler film forming material for suppressing pattern collapse of semiconductor substrates contains (C) an organic solvent. (C) The organic solvent can be, for example, ketone-based solvents, amide-based solvents, ether-based solvents, ester-based solvents, or mixtures thereof. (C) The organic solvent is simply one that can dissolve the polymer (A) mentioned above, the residual solvent removal promoter (B), and, where appropriate, the surfactant (D) mentioned later, without particular limitation. Specifically, solvents with a boiling point not exceeding 180°C, such as those described in paragraphs

[0091] to

[0092] of Japanese Patent Application Publication No. 2007-199653, 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 incorporated is preferably 50 to 1,800 parts by mass relative to 100 parts by mass of the polymer (A), more preferably 150 to 1,500 parts.

[0174] If such a filling film forming material is used to suppress pattern collapse of semiconductor substrates, it can be coated using spin coating, thus becoming a filling film for suppressing pattern collapse of semiconductor substrates with uniform film thickness and high degree of filling.

[0175] Furthermore, the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention may also contain a high-boiling-point solvent as an organic solvent, in addition to the solvent with a boiling point below 180°C. The high-boiling-point solvent is preferably one or more organic solvents with a boiling point above 180°C (a mixture of solvents with a boiling point below 180°C and solvents with a boiling point above 180°C). The high-boiling-point solvent is only required to dissolve the polymer and / or residual solvent to remove the accelerator, and is not particularly limited to 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-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, and 2-ethyl-1,3-hexanediol. Diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerol, 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-butanediol diacetate, 1,6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, dibutyl adipate, etc., can be used alone or in combination.

[0176] The boiling point of the aforementioned high-boiling-point solvent should be appropriately selected in conjunction with the heat treatment temperature of the filler film. A boiling point of 180℃ to 300℃ is preferred, and more preferably 200℃ to 300℃. Such a boiling point ensures an appropriate rate of evaporation during baking (heat treatment), resulting in sufficient thermal fluidity. Furthermore, it will not remain in the film after baking, thus not adversely affecting film properties such as etching resistance.

[0177] Furthermore, in the case of using high-boiling-point solvents as described above, it is preferable that the amount of high-boiling-point solvent added is 1 to 50 parts by mass relative to 100 parts by mass of solvent with a boiling point not reaching 180°C. With such an amount of addition, sufficient thermal fluidity can be provided during baking, and no residue will remain in the film, thus avoiding the risk of degradation of film properties such as etching resistance.

[0178] If the filling film forming material for suppressing semiconductor substrate pattern collapse is such a material, then a high-boiling-point solvent is added to the filling film forming material for suppressing semiconductor substrate pattern collapse to impart fluidity, thereby making it a filling film forming material for suppressing semiconductor substrate pattern collapse with a high degree of filling properties.

[0179] [(D) Surfactant]

[0180] In the filler film forming material for suppressing pattern collapse of semiconductor substrates of the present invention, a surfactant (D) may be added to improve the coatability of spin coating. The surfactant may be, for example, the surfactants described in

[0142] to

[0147] of Japanese Patent Application Publication No. 2009-269953. Examples include nonionic surfactants and fluorinated surfactants. The amount of surfactant added is preferably 0.01 to 10 parts, more preferably 0.05 to 5 parts, relative to 100 parts of the polymer.

[0181] [Metallic impurities]

[0182] The filler film forming material used to suppress pattern collapse of semiconductor substrates should ideally be as free of metal impurities as possible, considering the need to reduce substrate pattern contamination. The metal impurity content of the filler film forming material for suppressing pattern collapse of semiconductor substrates is preferably 10 ppb or less by mass, more preferably 5 ppb or less, even better 3 ppb or less, and especially preferably 1 ppb or less. By controlling the impurity content of each metal within the above range, the amount of metal impurities on the substrate surface after the filler film filling the uneven pattern is removed by dry etching can be reduced.

[0183] The aforementioned 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, with Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti being even more preferred. Metal impurities of the aforementioned elements include all metal particles, ions, colloids, complexes, oxides, and nitrides present in the filler film forming material used to suppress pattern collapse of semiconductor substrates, whether dissolved or undissolved.

[0184] By controlling the amount of impurities in each metal within the above range, it is possible to reduce the amount of metal impurities on the substrate surface after the filler film filling the embossed pattern is removed by dry etching, thereby preventing a decrease in device yield and reliability.

[0185] The amount of the aforementioned metal impurities on the substrate surface after the filler film filling the embossed pattern is removed by dry etching is 2.0 × 10E. +10 atoms / cm 2 The following is more ideal, 1.0×10E +10 atoms / cm 2 The following is even more ideal. The metal content on the substrate surface after the above-mentioned filler film is removed can be determined using an Expert VPD-ICP-MS or similar instrument manufactured by IAS Corporation.

[0186] [Manufacturing method of filler film forming material for suppressing pattern collapse of semiconductor substrate]

[0187] The filler film forming material for suppressing pattern collapse of semiconductor substrates can be manufactured by mixing (A) a polymer, (B) a residual solvent removal accelerator, (C) an organic solvent, and any other components to be incorporated as needed, and then filtering the resulting solution through a filter with a pore size of approximately 0.02 μm. The lower limit of the solid component concentration of the filler film forming material for suppressing pattern collapse of semiconductor substrates is preferably 0.1% by mass, more preferably 3% by mass, and even more preferably 5% by mass. The upper limit of the above solid component concentration is preferably 50% by mass, more preferably 40% by mass, and even more preferably 35% by mass. Here, "solid component" in the filler film forming material for suppressing pattern collapse of semiconductor substrates refers to components other than (C) the organic solvent.

[0188] When the solid content concentration of the filler film forming material for suppressing semiconductor substrate pattern collapse is within the aforementioned range, the film thickness of the coating of the filler film forming material for suppressing semiconductor substrate pattern collapse can be formed within a lower limit of 50 nm and an upper limit of 6000 nm. Therefore, it is useful as a filler film for various microstructures that are prone to substrate pattern collapse. Examples of microstructures that are prone to substrate pattern collapse include: line and spacing patterns in Logic FinFET structures, line and spacing patterns and island patterns in DRAM STI structures, pillar patterns in DRAM capacitor structures, hole patterns and slit patterns in 3D-NAND cell structures, etc.

[0189] Furthermore, the obtained filler film forming material for suppressing semiconductor substrate pattern collapse is preferably further filtered using a nylon filter (e.g., a filter using a nylon 66 membrane as the filter medium), an ion exchange filter, or a filter utilizing adsorption caused by the Zeta potential. In this way, by using a nylon filter, an ion exchange filter, or a filter utilizing adsorption caused by the Zeta potential, the metal content in the filler film forming material for suppressing semiconductor substrate pattern collapse can be easily and reliably reduced, and a filler film forming material for suppressing semiconductor substrate pattern collapse with a lower metal content can be obtained at low cost. Moreover, the filler film forming material for suppressing semiconductor substrate pattern collapse can also be purified using known methods such as chemical purification methods (e.g., water washing, liquid-liquid extraction), or combinations of chemical purification methods with physical purification methods (e.g., ultrafiltration, centrifugation) to reduce the aforementioned metal content.

[0190] <Semiconductor substrate processing methods>

[0191] Examples of filling film forming materials used in this invention for suppressing pattern collapse of semiconductor substrates include pattern collapse suppression treatment of semiconductor substrates with a high aspect ratio of 5 or higher. Figure 1 The details are as follows.

[0192] The semiconductor substrate processing method is a method of drying a semiconductor substrate whose surface has been patterned with raised and recessed designs. Preferably, the method of drying the semiconductor substrate includes the following steps:

[0193] (1) The step of cleaning the aforementioned patterned semiconductor substrate 1 with cleaning solution 2, or the step of cleaning the aforementioned patterned semiconductor substrate with cleaning solution 2 and then replacing it with rinsing solution 2 ( Figure 1 (A)

[0194] (2) The step of using the filling film forming material for suppressing semiconductor substrate pattern collapse as described above, replacing the aforementioned cleaning solution 2 or rinsing solution 2, and filling the filling film 3. Figure 1 (B)

[0195] (3) The step of heat-treating the aforementioned filler film 3 at a temperature of 100°C to 600°C for 10 to 600 seconds to harden it (hardened filler film 3a, Figure 1 (C)

[0196] (4) The step of removing the hardened filler film 3a from the aforementioned semiconductor substrate using dry etching (semiconductor substrate 1a after filler film removal, Figure 1 (D)).

[0197] In a semiconductor substrate processing method using the filler film forming material for suppressing semiconductor substrate pattern collapse, it is preferable to perform at least one of the following steps after wet etching or dry etching: a cleaning step of cleaning the semiconductor substrate with a cleaning solution and a rinsing step of rinsing the semiconductor substrate with a rinsing solution. Then, the filler film forming material for suppressing semiconductor substrate pattern collapse is applied to the patterned semiconductor substrate and dried. In this case, it is even more preferable to apply the filler film forming material for suppressing semiconductor substrate pattern collapse while the cleaning solution or rinsing solution is held on the substrate, thereby replacing the cleaning solution or rinsing solution to form a coating. Because this semiconductor substrate processing method uses the filler film forming material for suppressing semiconductor substrate pattern collapse, the semiconductor substrate pattern collapse suppression performance and the low metallicity of the semiconductor substrate surface after the filler film is removed are excellent.

[0198] The filler film forming material for suppressing pattern collapse of semiconductor substrates according to the present invention, in such a way as Figure 2 The processing method is also applicable to the lower resist film treated as a multilayer resist after the semiconductor substrate pattern is filled.

[0199] A method for processing a semiconductor substrate involves drying a semiconductor substrate with an already formed uneven pattern on its surface, and simultaneously performing a method for forming an uneven pattern on the semiconductor substrate that is different from the previously formed uneven pattern. The method is characterized by including the following steps:

[0200] (1) The step of cleaning the aforementioned patterned semiconductor substrate (semiconductor substrate 4 with a high aspect ratio pattern (Pattern-A)) with a cleaning solution, or the step of cleaning the patterned semiconductor substrate with a cleaning solution and then replacing it with a rinsing solution.

[0201] (2) The step of replacing the aforementioned cleaning solution or rinsing solution with the filling film forming material for suppressing semiconductor substrate pattern collapse as described above, and filling the filling film 5. Figure 2 (E))

[0202] (3) The step of heat-treating the aforementioned filler film at a temperature of 100°C to 600°C for 10 to 600 seconds to harden it (hardened filler film 5a, Figure 2 (F)

[0203] (4) The step of forming a silicon-containing photoresist interlayer film 6 by using a silicon-containing photoresist interlayer film material on the aforementioned hardened filler film 5a. Figure 2 (G))

[0204] (5) The step of forming a photoresist upper film 7 on the aforementioned silicon-containing photoresist intermediate film 6 using a photoresist composition. Figure 2 (H))

[0205] (6) Step 7a of forming a circuit pattern on the aforementioned resist film. Figure 2 (I))

[0206] (7) Using the aforementioned upper resist film with the circuit pattern 7a as a mask, the pattern is transferred to the aforementioned silicon-containing resist intermediate film by etching (silicon-containing resist intermediate film pattern 6a, Figure 2 (J)

[0207] (8) Using the aforementioned silicon-containing resist intermediate film with the transferred pattern as a mask, the step of etching to transfer the pattern onto the aforementioned hardened filler film (filler film pattern 5b, Figure 2 (K)

[0208] (9) Using the hardened filler film with the aforementioned transferred pattern as a mask, etching is performed on the semiconductor substrate on which the aforementioned raised and recessed pattern has been formed to form a raised and recessed pattern different from the aforementioned raised and recessed pattern (Semiconductor substrate pattern (after Pattern-B is formed) 4a, Figure 2 (L))

[0209] (10) The step of removing the hardened filler film from the semiconductor substrate by dry etching. Figure 2 (M)).

[0210] Thus, the filler film coated with the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention is also suitable for use as a lower resist film for semiconductor substrates with surface-formed raised and recessed patterns. The heat-treated filler film exhibits excellent solvent resistance, and therefore can be used in various pattern forming methods such as forming a silicon-containing intermediate film (silicon-containing resist intermediate film, inorganic hard mask intermediate film) on the filler film without removing it, and forming a conventional organic photoresist film as the upper resist film, etc. After forming a circuit pattern using a photoresist composition on a semiconductor substrate pattern with raised and recessed patterns coated with the filler film using etching as a transfer, the filler film can be removed by dry etching. Thus, by continuing to use the high-cleanliness filler film forming material for suppressing semiconductor substrate pattern collapse as a resist underlayer in a multilayer resist treatment without removing it, the steps of removing the filler film for suppressing semiconductor substrate pattern collapse and coating the resist underlayer in a multilayer resist treatment after cleaning the semiconductor substrate can be omitted. Alternatively, a drying step that does not use the filler film forming material for suppressing semiconductor substrate pattern collapse, such as drying with 2-propanol, can be replaced with the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention, thereby omitting the drying step and contributing to the rationalization of the process. Furthermore, not limited to the purpose of drying the semiconductor substrate, the resist underlayer in a multilayer resist treatment used for filling the pattern of the dried semiconductor substrate in the manufacturing process of a semiconductor device can also be used.

[0211] The above-mentioned multilayer photoresist treatments include two-layer photoresist treatments containing silicon, three-layer photoresist treatments using a silicon-containing intermediate film, four-layer photoresist treatments using a silicon-containing intermediate film and an organic thin film, and two-layer photoresist treatments without silicon. However, considering the anti-reflective performance and cost, three-layer photoresist treatments using a silicon-containing intermediate film are preferable.

[0212] The aforementioned multilayer photoresist-treated silicon-containing photoresist interlayer film can also ideally utilize a polysilsesquioxane-based interlayer film. By imparting an anti-reflective effect to the silicon-containing photoresist interlayer film, reflection can be suppressed. For silicon-containing photoresist interlayer films with anti-reflective effects, polysilsesquioxanes with anthracene as the suspending group and cross-linked by acid or heat are preferable for 248nm and 157nm exposure applications, while polysilsesquioxanes with phenyl or silicon-silicon bond-containing light-absorbing groups as the suspending group and cross-linked by acid or heat are preferable for 193nm exposure applications.

[0213] In this situation, spin coating is simpler and more cost-effective than CVD for forming silicon-containing photoresist interlayer films.

[0214] When forming an inorganic hard mask interlayer on a filler film, silicon oxide films, silicon nitride films, and silicon oxide nitride films (SiON films) can be formed using methods such as CVD and ALD. For example, a method for forming a silicon nitride film is described in Japanese Patent Application Publication No. 2002-334869 and International Publication No. 2004 / 066377. A thickness of 5–200 nm for the inorganic hard mask interlayer is ideal, and 10–100 nm is more preferred. Furthermore, for the inorganic hard mask interlayer, using a SiON film, which has high anti-reflective properties, is most ideal. Because the semiconductor substrate temperature reaches 300–500°C during SiON film formation, the filler film must be able to withstand temperatures of 300–500°C.

[0215] The aforementioned multilayer photoresist top film can be either positive or negative, and can use the same composition as commonly used photoresist. After spin-coating the photoresist composition, pre-baking at 60–180°C for 10–300 seconds is preferred. Then, exposure is performed as usual, followed by post-exposure baking (PEB) and development to obtain the photoresist top film pattern. Furthermore, there are no particular limitations on the thickness of the photoresist top film, but 30–500 nm is ideal, especially 50–400 nm.

[0216] The formation of the circuit pattern (resist upper film pattern) of the above-mentioned multilayer resist treatment is preferably achieved by photolithography using light with wavelengths of 10nm to 300nm, direct drawing using electron beams, nanomolding, or a combination thereof.

[0217] Furthermore, exposure light can include high-energy rays with wavelengths below 300nm, specifically such as far ultraviolet light, KrF excimer laser (248nm), ArF excimer laser (193nm), F2 laser (157nm), Kr2 laser (146nm), Ar2 laser (126nm), soft X-rays (EUV) of 3-20nm, electron beam (EB), ion beam, X-rays, etc.

[0218] Furthermore, it is preferable to use alkaline development or organic solvents to develop circuit patterns.

[0219] The cleaning solutions used for cleaning semiconductor substrates with formed raised and recessed patterns can include, for example, stripping solutions containing sulfate ions, cleaning solutions containing chloride ions, cleaning solutions containing fluoride ions, alkaline cleaning solutions containing nitrogen compounds, and cleaning solutions containing phosphoric acid. It is preferable that these cleaning solutions contain hydrogen peroxide. Cleaning steps using two or more cleaning solutions can be performed consecutively. For cleaning solutions containing sulfate ions, a sulfuric acid-hydrogen peroxide aqueous solution (SPM) is ideal, suitable for removing organic substances such as photoresists. For cleaning solutions containing chloride ions, a mixed aqueous solution of hydrogen peroxide and hydrochloric acid (SC-2) is ideal, suitable for removing metals. For cleaning solutions containing fluoride ions, a mixed aqueous solution of hydrofluoric acid and ammonium fluoride can be used. For alkaline cleaning solutions containing nitrogen compounds, a mixed aqueous solution of hydrogen peroxide and ammonia (SC-1) is ideal, suitable for removing particulate matter.

[0220] The rinsing solution used for rinsing the semiconductor substrate with the aforementioned raised and recessed patterns can include ultrapure water or water-soluble alcohols. 2-Propanol is preferred as the water-soluble alcohol. The rinsing steps using two or more rinsing solutions can be performed consecutively. It is preferable to perform an alcohol rinsing process after rinsing with ultrapure water, replacing the rinsing with 2-propanol, and then coat the filler film forming material used to suppress pattern collapse of the semiconductor substrate.

[0221] The aforementioned cleaning or rinsing solution is preferably a liquid containing one or more of water, water-soluble alcohol, and fluorine compounds.

[0222] The filling film forming material used to suppress pattern collapse of semiconductor substrates is not particularly limited to the coating method of the semiconductor substrate, and can be implemented by appropriate methods such as spin coating, casting coating, and roll coating.

[0223] There are no particular restrictions on the drying method for the coating of the filler film forming material used to suppress pattern collapse on semiconductor substrates, and it is usually carried out by heating in an atmospheric gas environment. The lower limit of the heating temperature is not particularly limited, but 40°C is ideal, 60°C is preferred, and 100°C is even more preferred. The upper limit of the heating temperature is ideally 400°C, preferably 350°C, and even more preferred 300°C. The lower limit of the heating time is ideally 15 seconds, preferably 30 seconds, and even more preferred 45 seconds. The upper limit of the heating time is ideally 1,200 seconds, preferably 600 seconds, and even more preferred 300 seconds.

[0224] Thus, by coating the semiconductor substrate with the filling film forming material for suppressing semiconductor substrate pattern collapse onto a semiconductor substrate with an already formed concave-convex pattern and drying it, the filling film forming material for suppressing semiconductor substrate pattern collapse can be filled into the concave portions of the pattern, thereby suppressing the collapse of the pattern when it contacts an adjacent pattern. Furthermore, since the filling film forming material for suppressing semiconductor substrate pattern collapse uses (A) a polymer, it can be polymerized due to the crosslinking reaction accompanied by heat treatment and (B) the removal of residual solvent from the accelerator, resulting in heat resistance to the filling film. Such a filling film, even if partially or entirely heated during removal from the semiconductor substrate by dry etching or the like, easily suppresses thermal melting and maintains its strength, thus suppressing the collapse of the semiconductor substrate pattern and reliably removing it by dry etching or the like.

[0225] The gas environment during baking can include not only air, but also inert gases such as N2, Ar, and He. In this case, the gas environment can be set to have an oxygen concentration of less than 0.1%. Furthermore, the baking temperature and other parameters can be as described above. Even if the semiconductor substrate with the aforementioned raised and recessed patterns contains materials that are unstable to heating in an oxygen-filled gas environment, it will not cause degradation of the semiconductor substrate and can promote the cross-linking reaction of the filler film forming material used to suppress pattern collapse of the semiconductor substrate.

[0226] The aforementioned semiconductor substrate with formed raised and recessed patterns is acceptable as long as the pattern is formed on a semiconductor substrate other than the resist pattern; there are no particular restrictions. Semiconductor substrates with semiconductor substrate patterns formed on at least one side and containing silicon atoms or metal atoms are preferred. Semiconductor substrates with metals, metal nitrides, metal oxides, silicon oxides, silicon nitride films, silicon, or mixtures thereof as the main component are even more preferred. Here, "main component" refers to the component with the highest content, for example, a component with a content of 50% by mass or more. Examples of metal atoms include titanium, tungsten, hafnium, zirconium, chromium, germanium, copper, silver, gold, aluminum, indium, gallium, arsenic, palladium, iron, tantalum, iridium, cobalt, manganese, and molybdenum.

[0227] The material constituting the above-mentioned semiconductor substrate pattern is, for example, the same material as exemplified in the above-mentioned semiconductor substrate.

[0228] The shape of the aforementioned semiconductor substrate pattern is not particularly limited, and examples include fine structures such as line and spacing patterns, island patterns, hole patterns, pillar patterns, and slit patterns. The upper limit for the average spacing of the aforementioned line and spacing patterns and island patterns is preferably 300 nm, more preferably 100 nm, even more preferably 50 nm, and 30 nm is particularly desirable. The upper limit for the average spacing of the aforementioned hole patterns and pillar patterns is preferably 300 nm, more preferably 150 nm, and even more preferably 100 nm. The upper limit for the average spacing of the aforementioned slit patterns is preferably 2,000 nm, and even more preferably 1,500 nm. By applying this semiconductor substrate processing method to a semiconductor substrate with such finely spaced patterns, the excellent semiconductor substrate pattern collapse suppression can be maximized.

[0229] The lower limit of the average height of the aforementioned line and spacing patterns and island patterns is preferably 100 nm, more preferably 200 nm, even better than 300 nm, and especially preferably 400 nm. The upper limit of the average width (e.g., at the center of the height direction) of the aforementioned semiconductor substrate's line and spacing patterns and island patterns is preferably 50 nm, more preferably 40 nm, even better than 30 nm, and especially preferably 20 nm. The lower limit of the aforementioned semiconductor substrate's aspect ratio (average height of the pattern / average width of the pattern) is preferably 5, more preferably 10, more preferably 15, and especially preferably 20.

[0230] The lower limit of the average height of the aforementioned hole pattern is preferably 3,000 nm, more preferably 5,000 nm, even more preferably 7,000 nm, and especially preferably 10,000 nm. The upper limit of the average width of the holes in the aforementioned semiconductor substrate (e.g., based on the center portion 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 height of the pattern / average width of the pattern) of the aforementioned semiconductor substrate is preferably 10, more preferably 30, even more preferably 50, and especially preferably 100.

[0231] The lower limit of the average height of the aforementioned pillar pattern is preferably 100 nm, more preferably 200 nm, even better than 300 nm, and especially preferably 400 nm. The upper limit of the average width of the pillars in the aforementioned semiconductor substrate (e.g., based on the central portion in the height direction) is preferably 50 nm, more preferably 40 nm, even better than 30 nm, and especially preferably 20 nm. The lower limit of the aspect ratio (average height of the pattern / average width of the pattern) of the aforementioned semiconductor substrate is preferably 5, more preferably 10, even better than 15, and especially preferably 20.

[0232] The lower limit of the average height of the aforementioned slit pattern is preferably 3,000 nm, more preferably 5,000 nm, even more preferably 7,000 nm, and especially preferably 10,000 nm. The upper limit of the average width of the slits in the aforementioned semiconductor substrate (e.g., based on the center portion 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 (average height of the pattern / average width of the pattern) of the aforementioned semiconductor substrate is preferably 3, more preferably 5, even more preferably 10, and especially preferably 15.

[0233] The filler film forming material used to suppress pattern collapse on semiconductor substrates is widely applicable regardless of the type of microstructures mentioned above.

[0234] Furthermore, in this invention, a semiconductor substrate processing method comprising the following steps is preferred:

[0235] The steps are: a step of filling a semiconductor substrate with an aspect ratio of 5 or more on a surface with an already formed uneven pattern using the filling film forming material for suppressing semiconductor substrate pattern collapse as described above; and a step of removing the aforementioned filling film.

[0236] Furthermore, it is preferable to fill the recesses of the pattern by applying a coating film formed from the semiconductor substrate pattern collapse suppression forming material. That is, the filling film forming material for suppressing semiconductor substrate pattern collapse can ideally be used as a filling film. Also, there are no particular limitations on the thickness of the coating film, but the lower limit of the average thickness of the coating film on the raised surface 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 above average thickness is preferably 5 μm, more preferably 3 μm, more preferably 2 μm, and especially preferably 0.5 μm.

[0237] The coating on the semiconductor substrate formed by the filler film forming material for suppressing semiconductor substrate pattern collapse can be removed in the gas phase. This removal can be achieved by, for example, heat treatment, plasma treatment, dry etching (ashing), ultraviolet irradiation, electron beam irradiation, etc., but dry etching (ashing) is preferred.

[0238] Dry etching can be performed using known dry etching equipment. The etching gas used in dry etching can be appropriately selected based on the elemental composition of the filler film used to suppress the collapse of the aforementioned substrate pattern to be etched. Examples of gases that can be used 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 passive gases such as He, N2, and Ar. Furthermore, these gases can also be mixed.

[0239] [Example]

[0240] The following synthetic examples, embodiments, and comparative examples illustrate the present invention in more detail, but the present invention is not limited to these examples. Furthermore, the molecular weight and dispersity were determined by gel permeation chromatography (GPC) using tetrahydrofuran as the dissolution solution, yielding the weight-average molecular weight (Mw), number-average molecular weight (Mn), and dispersity (Mw / Mn) of polystyrene.

[0241] [Compound Synthesis]

[0242] Synthesis of polymer (A-1)

[0243] Under nitrogen atmosphere, 216.3 g of m-cresol, 130.0 g of 37% formaldehyde solution, 10.8 g of oxalic acid, and 200 g of dioxane were added, and the reaction was carried out at an internal temperature of 100 °C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and 2,000 ml of MIBK (methyl isobutyl ketone) was added. The mixture was washed six times with 500 ml of pure water. The organic layer was recovered and dried under reduced pressure to obtain polymer (A-1). The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were calculated using GPC. The results showed that Mw = 7,000 and Mw / Mn = 7.5.

[0244] [Chemistry 18]

[0245]

[0246] Synthesis of polymer (A-2)

[0247] Under 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. Then, a pre-mixed and homogenized mixture of 8.0 g of p-toluenesulfonic acid monohydrate and 8.0 g of PGME was 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 pure water. The organic layer was then dried under reduced pressure. 300 g of THF was added to the residue to prepare a homogenous solution, which was then allowed to precipitate in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed twice with 500 g of hexane, and recovered. The recovered crystals were dried under vacuum at 70 °C to obtain polymer (A-2). The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were determined using GPC. The results showed that Mw = 4,000 and Mw / Mn = 3.0.

[0248] [Chemistry 19]

[0249]

[0250] Synthesis of polymer (A-3)

[0251] Under nitrogen atmosphere, 100.0 g of polymer (A-1), 172.3 g of potassium carbonate, and 500 g of DMF were added to prepare 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. Further, the organic layer was washed six times with 300 g of 3% nitric acid aqueous solution and 300 g of pure water, and then dried under reduced pressure. 300 g of THF was added to the residue to prepare a homogeneous solution, which was then precipitated in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed twice with 500 g of hexane, and recovered. The recovered crystals were dried under vacuum at 70 °C to obtain polymer (A-3). The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were calculated using GPC, and the results were Mw = 10,000 and Mw / Mn = 3.1.

[0252] [Chemistry 20]

[0253]

[0254] Synthesis of polymer (A-4)

[0255] Phenol (188.2 g), 37% formaldehyde solution (48.7 g), oxalic acid (9.4 g), and dioxane (200 g) were added under nitrogen atmosphere, and the reaction was carried out at an internal temperature of 100 °C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and 2,000 ml of MIBK was added. 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 moisture, solvent, and residual monomers, yielding polymer (A-4). The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were calculated using GPC, resulting in Mw = 1,500 and Mw / Mn = 1.5.

[0256] [Chemistry 21]

[0257]

[0258] Synthesis of polymer (A-5)

[0259] Phenol (188.2 g), 37% formaldehyde solution (113.6 g), oxalic acid (9.4 g), and dioxane (200 g) were added under nitrogen atmosphere, and the reaction was carried out at an internal temperature of 100°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and MIBK (2000 ml) was added. The mixture was washed six times with 500 ml of pure water. The organic layer was recovered and concentrated to approximately 25 wt% based on the yield. Then, 1000 g of a 1:1 (weight ratio) mixture of methanol and pure water was added while stirring to precipitate the polymer. After standing for 1 hour, the supernatant was decanted. The precipitate was recovered and dried under reduced pressure to obtain polymer (A-5). The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were calculated using GPC. The results showed that Mw = 10,000 and Mw / Mn = 1.5.

[0260] [Chemistry 22]

[0261]

[0262] Synthesis of polymer (A-6)

[0263] 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 under nitrogen atmosphere, 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, allowing it to precipitate in 3,000 g of heptane. The precipitated crystals were separated by filtration, washed twice with 500 g of heptane, and recovered. The recovered crystals were dried under vacuum at 70 °C to obtain polymer (A-6). The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were calculated using GPC, and the results showed that Mw = 4,500 and Mw / Mn = 2.0.

[0264] [Chemistry 23]

[0265]

[0266] Preparation of filler film forming material for suppressing pattern collapse on semiconductor substrates

[0267] The components used in the preparation of the filler film forming material for suppressing pattern collapse on semiconductor substrates are shown below.

[0268] [(A) Polymer]

[0269] The following discloses polymers (A-1) to (A-6) used in filling film forming materials for suppressing pattern collapse on semiconductor substrates.

[0270] [Chemistry 24]

[0271]

[0272] [(B) Residual solvent removal accelerator]

[0273] The following discloses the various (B) residual solvent removal promoters used in the filler film forming material for suppressing pattern collapse on semiconductor substrates.

[0274] [Chemistry 25]

[0275]

[0276] [Composition FM-1]

[0277] 100 parts by weight of (A-1) as (A) polymer, 15 parts by weight of (B-1) as (B) residual solvent removal promoter, and 0.25 parts by weight of (D-1) FC-4430 (manufactured by 3M) as (D) surfactant were dissolved in 1,150 parts by weight of (C-1) propylene glycol monomethyl ether acetate (PGMEA) as (C) organic solvent. The resulting solution was filtered through a membrane filter with a pore size of 0.02 μm to prepare a filler film forming material (FM-1) for suppressing pattern collapse of semiconductor substrates.

[0278] [Compositions FM-2~4 and comparisons FM-1~11]

[0279] The types and contents of each component are shown in Tables 1-3. Except for these, the process is the same as for FM-1, to prepare various filler film forming materials for suppressing pattern collapse of semiconductor substrates. Also, in Tables 1-3, "―" indicates that the component was not used. The acid generating agent (PAG) uses the following formula (E-1), and the high-boiling solvent (C-2) uses 1,6-diacetoxyhexane: boiling point 260°C.

[0280] [Chemistry 26]

[0281]

[0282] [Table 1]

[0283]

[0284] [Table 2]

[0285]

[0286] [Table 3]

[0287]

[0288] <Formation of the Filler Membrane>

[0289] Filler film forming materials for suppressing semiconductor substrate pattern collapse, prepared by FM-1 to 4 and comparative FM-3 to 11, are coated onto the surface of a semiconductor substrate with an already formed uneven pattern. The filler film is then baked at 250°C for 60 seconds in atmospheric conditions. The semiconductor substrates described above are silicon wafers of three types (semiconductor substrates A to C) with different uneven patterns formed on their surfaces.

[0290] Semiconductor substrate A: A silicon wafer with a line and spacing pattern of aspect ratio 40, having a height of 6,000 nm, an average line width of 150 nm, an average pitch of 400 nm between lines.

[0291] Semiconductor substrate B: A silicon wafer with a hole pattern of aspect ratio 20, having a height of 8,000 nm, an average hole width of 380 nm, and an average hole pitch of 500 nm.

[0292] Semiconductor substrate C: A silicon wafer with a line and spacing pattern of aspect ratio 13, having a height of 400 nm, an average line width of 30 nm, and an average pitch of 45 nm between lines.

[0293] For each of the filler film forming materials used to suppress pattern collapse of semiconductor substrates in FM-1 to 4 and Comparative FM-1 to 11, the film thickness uniformity, fillability, and pattern collapse suppression performance were evaluated according to the following methods. Furthermore, for Examples 4-1 and Comparative Example 4-1, the amount of metal impurities on the surface of the semiconductor substrate after the filler film was removed was evaluated according to the following methods.

[0294] [Film thickness uniformity]

[0295] Cross-sections of silicon wafer substrates with the aforementioned filler films (FM-1 to 4 and Comparative FM-3 to 11) were cut out, and the film thickness uniformity of each filler film was evaluated using FE-SEM (Hitachi Advanced Technology Corporation's "S4800"). Comparative Examples 1-1 to 1-2 did not have filler films formed, so coating performance was not evaluated. The evaluation points are shown below.

[0296] Semiconductor substrate A: The film thickness on the pattern of the densely patterned area. The film thickness 1 at the center of the silicon wafer substrate and the film thickness 2 at the outer periphery are measured. When the film thickness difference between film thickness 1 and film thickness 2 is less than 60nm, it is rated as "A" (excellent), 61-90nm is rated as "B" (good), and more than 91nm is rated as "C" (poor).

[0297] Semiconductor substrate B: The film thickness 1 at the center of the silicon wafer substrate and the film thickness 2 at the outer periphery are measured. When the difference between film thickness 1 and film thickness 2 is less than 100nm, it is rated as "A" (excellent), 101-150nm is rated as "B" (good), and more than 151nm is rated as "C" (poor).

[0298] Semiconductor substrate C: The film thickness 1 at the center of the silicon wafer substrate and the film thickness 2 at the outer periphery are measured. When the difference between film thickness 1 and film thickness 2 is less than 4nm, it is rated as "A" (excellent), 5-6nm is rated as "B" (good), and more than 7nm is rated as "C" (poor).

[0299] [Table 4]

[0300]

[0301]

[0302] As shown in Table 4, Examples 1-1 to 4-1, which used the filler film forming materials (FM-1 to 4) for suppressing pattern collapse of semiconductor substrates according to the present invention, ensured excellent film thickness uniformity even on substrates with high aspect ratio embossed patterns. However, Comparative Examples 3-1, 5-1, and 6-1, lacking the residual solvent removal promoter (B-1), could not ensure film thickness uniformity due to the sublimation of low molecular weight components in polymer (A). This suggests that the addition of the residual solvent removal promoter (B-1) helps improve film thickness uniformity. Furthermore, Comparative Example 5-1 shows that when using polymer (A-4) with a small molecular weight and narrow molecular weight dispersion (A-4), the amount of sublimation is high, resulting in a significant deterioration in 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. This suggests that a molecular weight of polymer (A) of 3000 or higher is preferable to obtain sufficient film thickness uniformity. On the other hand, as seen in Comparative Example 8-1 using Comparative FM-8, when the content of the residual solvent removal accelerator (B-1) exceeds 50 parts by mass relative to 100 parts by mass of polymer (A), deterioration in film thickness uniformity is observed due to the generation of sublimation products from the residual solvent removal accelerator (B). Therefore, it is known that there is an optimal amount of residual solvent removal accelerator (B). In this invention, it should be 0.1 to 40 parts by mass relative to 100 parts by mass of polymer (A), with 15 parts by mass being preferable. Furthermore, regarding the residual solvent removal accelerator (B), Comparative Example 9-1 using Comparative FM-9, which uses an additive (B-2) containing a compound not represented by general formula (2), has insufficient crosslinking reactivity with polymer (A), suggesting that film thickness uniformity cannot be ensured. Therefore, it can be concluded that the residual solvent removal accelerator (B) must contain a compound represented by general formula (2).

[0303] [Fill]

[0304] Cross-sections of each silicon wafer substrate with the aforementioned filler films (FM-1 to 4, and Comparative FM-3 to 11) were cut out, and the filling performance of each filler film was evaluated using an electron microscope (S-4700) manufactured by Hitachi, Ltd. Regarding the filling performance, an "A" (Excellent) rating was given when the filler film was buried to the bottom of the pattern without cracks, deformation such as bending, and no exposure at the top of the pattern. A "B" (Good) rating was given when the filler film was buried to the bottom of the pattern but voids or cracks were observed, or when the pattern shape was bent or deformed even though the filler film was buried to the bottom of the pattern. A "C" (Poor) rating was given when the filler film was not buried to the bottom of the pattern and the top was exposed. In Comparative Examples 1-2 to 2-2, no filler films were formed, so the filling performance was not evaluated.

[0305] [Table 5]

[0306]

[0307]

[0308] As shown in Table 5, Examples 1-2 to 4-2 of the present invention, which uses a combination of (A) polymer and (B) residual solvent removal promoter, to suppress the pattern collapse of semiconductor substrates, can ensure excellent filling properties in each semiconductor substrate with a high aspect ratio embossed pattern.

[0309] Comparative Examples 3-2 and 5-2, which used Comparative FM-3 and Comparative FM-5 without the (B) residual solvent detachment promoter, showed porosity in the filled films. If the aspect ratio of the semiconductor substrate pattern increases, the residual solvent in the filled film of the recessed areas becomes more difficult to detach. It is inferred that due to heat treatment, the residual solvent carried by the polymer in the filled recesses will escape, but at the same time, the filled film will also harden, causing the residual solvent trapped in the hardened film to bubble and form pores.

[0310] The filler film forming materials (FM-1 to 4) for suppressing semiconductor substrate pattern collapse of the present invention, by adding a residual solvent detachment promoter (B), facilitate the detachment of residual solvent held by polymer (A) from the filler film, thus forming a pore-free filler film. The mechanism by which the residual solvent carried by polymer (A) becomes easier to detach is presumably due to the high-dimensional cross-linking of the compound between polymer (A) and the residual solvent detachment promoter (B), reducing the affinity between polymer (A) and organic solvent (C), and making the organic solvent more volatile.

[0311] On the other hand, Comparative Example 4-2, which used Comparative FM-4 containing an acid-generating agent, showed pores and pattern bending in the filler film. It is presumed that when the filler film forming material used to suppress semiconductor substrate pattern collapse contains an acid-generating agent, the crosslinking reaction between (A) polymer and (B) residual solvent removal accelerator proceeds more rapidly. Due to the rapid shrinkage of the filler film, strong physical stress is applied to the semiconductor substrate pattern, resulting in pattern bending. Furthermore, it is presumed that the hardening of the filler film is completed before the residual solvent removal is finished, so the residual solvent trapped in the hardened film bubbles and forms pores. The undesirable phenomena observed in Comparative Example 8-2, which used Comparative FM-8 containing 50 parts by mass of (B) residual solvent removal accelerator, are presumably for the same reason as Comparative Example 4-2: excessive addition of (B) residual solvent removal accelerator accelerates the crosslinking reaction. Therefore, in this invention, the composition does not contain acid generating agents, and (B) the content of residual solvent removal accelerator should be 0.1 to 40 parts by weight relative to 100 parts by weight of polymer, preferably 15 parts by weight.

[0312] Furthermore, when comparing FM-6 and FM-7, a narrow molecular weight dispersion (Mw / Mn) in the polymer results in poor flowability. Consequently, in Comparative Examples 6-2 and 7-2, the filler film was not buried to the bottom of the pattern, and the top of the pattern was exposed. This result indicates that, for better flowability, a wider molecular weight dispersion (Mw / Mn) of the polymer (A) used in the filler film forming material for suppressing semiconductor substrate pattern collapse is ideal. In this invention, it needs to be in the range of 2.50 ≤ Mw / Mn ≤ 9.00.

[0313] Comparative Example 9-2 of Comparative FM-9, which used an additive (B-2) that did not contain the compound represented by general formula (2) in relation to the residual solvent removal promoter (B), showed insufficient removal of the residual solvent carried by the polymer (A), confirming that there were pores in the filled film. From this result, it is clear that the residual solvent removal promoter (B) containing the compound represented by (2) is required in this invention.

[0314] In Comparative Example 10-2, cracks were observed at the interface between the semiconductor substrate pattern and the filler film. This is presumably due to the high hydrophobicity of polymer (A-3), which reduces the adhesion between the filler film and the semiconductor substrate pattern due to heat treatment. In Example 3-2, by mixing 30 parts by mass of polymer (A-1) with 70 parts by mass of polymer (A-3), the adhesion to the semiconductor substrate pattern was improved, and excellent filling properties were observed. Polymer (A-3) has low viscosity and excellent filling properties, but its adhesion to the semiconductor substrate is deteriorated; therefore, it is preferable to use it in combination with polymer (A-1). In this invention, a mixing ratio of (A-1) / (A-3) = 30 parts by mass / 70 parts by mass is preferred.

[0315] Comparative Example 11-2 of Comparative FM-11, which used a polymer (A-6) containing a structural unit not represented by the general formula (1) of the present invention, had a high amount of residual solvent. Therefore, even with the use of the residual solvent removal promoter (B), the removal of residual solvent from the polymer was insufficient, and pores were confirmed in the filled film. As a result, it can be said that a polymer having a structural unit represented by the general formula (1) is necessary in the present invention.

[0316] [Pattern Collapse Inhibition]

[0317] Dry etching (ashing) was performed using the Telius etching apparatus manufactured by Tokyo Powertech to remove the filler film. The number of lines remaining on the semiconductor substrate C after removal without collapse was determined using an electron microscope (S-4700). Regarding the collapse suppression performance of the substrate pattern, a rating of "A" (Excellent) was given when the proportion of remaining lines without collapse exceeded 90%, "B" (Good) when the proportion was between 70% and 90%, and "C" (Poor) when the proportion was below 70%. The specific manifestations of poor substrate pattern collapse suppression are shown below. Figure 3 In Comparative Examples 1-3 and 2-3, Comparative FM-1 and Comparative FM-2 were coated respectively, and the pattern collapse suppression of the substrates after baking in the atmosphere for 60 seconds was evaluated.

[0318] The dry etching (ashing) conditions are as follows.

[0319]

[0320] [Table 6]

[0321]

[0322] As shown in Table 6, Examples 1-3 to 4-3, which used the filler film forming materials (FM-1 to 4) of the present invention for suppressing pattern collapse of semiconductor substrates, ensured excellent pattern collapse suppression even on semiconductor substrates with high aspect ratio embossed patterns. However, Comparative Examples 1-3 to 2-3 showed significant pattern collapse (semiconductor substrate 8 with high aspect ratio patterns, and cleaning solution or rinsing solution 9...). Figure 3 (L)), Semiconductor substrate pattern 8a (after drying, the pattern collapses) Figure 3 The results show that water and 2-propanol in the prior art are insufficient to suppress the collapse of high aspect ratio patterns, and the processing method using the filling film forming materials (FM-1 to 4) for suppressing the collapse of semiconductor substrate patterns of the present invention is preferred.

[0323] On the other hand, in the above-mentioned filling performance evaluation, comparative examples 3-2 to 9-2 and 11-2, which showed porosity in the filling film, and comparative examples 3-3 to 9-3 and 11-3, which showed pattern collapse, were also observed (semiconductor substrate 10 and filling film 11 with high aspect ratio patterns). Figure 3 (N)), a hardened filled membrane 11a containing pores, and pores 12 ( Figure 3 (O)), Semiconductor substrate pattern 10a (after removal of porous filling film, pattern collapse). Figure 3 As a result, the higher the aspect ratio of the pattern, the greater the impact of the pores in the filler film on pattern collapse when the filler film is removed. Therefore, it can be said that the filling performance of the filler film forming material used to suppress the collapse of semiconductor substrate patterns is necessary to ensure that the recesses of the semiconductor substrate pattern are filled.

[0324] Furthermore, in the above-mentioned filling performance evaluation, Comparative Examples 4-3 and 8-3 (with high aspect ratio pattern semiconductor substrate 13 and filling film 14) were processed after processing Comparative Examples 4-2 and 8-2 where bending of the pattern shape was observed. Figure 3 (Q)), the pattern shape 13a bent due to the thermal shrinkage of the filler film, and the hardened filler film 14a containing pores. Figure 3 (R)), Semiconductor substrate pattern 13b after pattern collapse following removal of porous filling film (R) Figure 3 (S)), and Comparative Example 10-3 after processing the Comparative Example 10-2 in which cracks were observed at the interface between the semiconductor substrate pattern and the filling film (semiconductor substrate 15 with a high aspect ratio pattern and filling film 16) Figure 3 (T)), hardened filler film 16a containing cracks, and crack 17 ( Figure 3 (U)), Semiconductor substrate pattern 15a (with cracked filler film removed after pattern collapse) Figure 3 Significant pattern collapse was also observed in (V). This result indicates that not only porosity in the filler, but also defects such as pattern curvature and cracks at the filler-substrate interface can cause pattern collapse in the semiconductor substrate after filler removal. It is inferred that the filler film forming material of this invention, which contains (A) a polymer and (B) a residual solvent removal promoter and is free of acid-generating agents, for suppressing semiconductor substrate pattern collapse, can suppress defects such as porosity in the filler film, pattern curvature, and cracks at the filler-substrate interface, and can form a filler film with high suppression of semiconductor substrate pattern collapse after filler removal.

[0325] [Metal impurities on the surface of the semiconductor substrate after the filler film is removed]

[0326] The filling film materials for suppressing semiconductor substrate pattern collapse, as described in Table 7 for Examples 1-4 and Comparative Examples 1-4 with different metal impurity levels, were coated onto the surface of a silicon substrate and baked at 250°C for 60 seconds to form a filling film with a thickness of 3,000 nm. The filling film was then removed by dry etching, and the metal impurity level on the silicon substrate surface was evaluated using an Expert VPD-ICP-MS (manufactured by IAS). The metals evaluated were Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti, with an impurity level of 2.0 × 10⁻⁶ E. +10 (atoms / cm 2 The following ratings are "A" (good) and exceed 2.0 × 10⁻⁶. +10 (atoms / cm 2 It was rated "B" (poor) at the time.

[0327] [Table 7]

[0328]

[0329] [Table 8]

[0330]

[0331] As shown in Table 8, in the filler film forming materials for suppressing pattern collapse of semiconductor substrates of the present invention (Examples 1-4), the metal impurity content is 3 ppb or less. Therefore, the metal impurity content on the surface of the semiconductor substrate after the filler film is removed can maintain a maximum value of 2.0 × 10E. +10 (atoms / cm 2 The surface cleanliness is excellent, as shown in Comparative Examples 1-4, where the metal impurity content exceeds 10 ppb, and the metal impurity content on the semiconductor substrate surface after the filler film is removed exceeds 2.0 × 10⁻⁶ ppm. +10 (atoms / cm 2 As a result, in this invention, in order to reduce the amount of metal impurities on the surface of the semiconductor substrate after the filler film is removed, it is preferable that the amount of metal impurities in the filler film forming material used to suppress semiconductor substrate pattern collapse is 3 ppb or less. By controlling the amount of impurities of each metal within the above range, it is possible to prevent a decrease in device yield and reliability. Furthermore, in this evaluation, a filler film with a thickness of 3,000 nm is used for evaluation in a way that the amount of metal impurities in the filler film forming material used to suppress semiconductor substrate pattern collapse affects performance. In order to evaluate the cleanliness after the filler film is removed, strict evaluation conditions are adopted.

[0332] The filler film coated with the filler film forming material for suppressing pattern collapse of semiconductor substrates according to the present invention can also be ideally used as a lower resist film for semiconductor substrates with surface-mounted raised and recessed patterns. The filler film, after heat treatment, exhibits excellent solvent resistance and can be used in various pattern forming methods, such as forming a silicon-containing intermediate film (silicon-containing resist intermediate film, inorganic hard mask intermediate film) on the filler film without removing it, and then forming a conventional organic photoresist film as the upper resist film. After forming a circuit pattern using a photoresist composition onto a semiconductor substrate pattern with raised and recessed patterns coated with the filler film using etching as a transfer process, the filler film can be removed by dry etching. Solvent resistance, flatness, and pattern forming tests were evaluated for the filler film forming materials for suppressing pattern collapse of semiconductor substrates (FM-1 to 4, comparative FM-3 to 11) listed in Tables 1 to 3 above using the following methods.

[0333] Solvent resistance

[0334] The aforementioned filler film forming materials (FM-1 to 4, Comparative FM-3 to 11) for suppressing pattern collapse of semiconductor substrates were coated on a silicon substrate. After baking at 250°C for 60 seconds, the film thickness (a[Å]) was measured. PGMEA solvent was applied to the substrate, left for 30 seconds, spun dry, and baked at 100°C for 60 seconds to evaporate the PGMEA. The film thickness (b[Å]) was then measured. The difference in film thickness before and after PGMEA treatment was calculated (residual film rate: (b / a)×100). The results are shown in Table 9 below. Comparative Examples 1-5 to 2-5 did not form filler films, therefore solvent resistance was not evaluated.

[0335] [Table 9]

[0336]

[0337] As shown in Table 9, the filler film forming materials (FM-1 to 4) for suppressing semiconductor substrate pattern collapse of the present invention use a polymer having the structural unit represented by the above general formula (1) (A), which can be molecularly increased through a crosslinking reaction accompanied by heat treatment and (B) residual solvent removal accelerator, resulting in a filler film with excellent solvent resistance. On the other hand, comparative examples 3-5, 5-5, and 6-5, which use comparative FM-3, 5, and 6 without the residual solvent removal accelerator (B), have insufficient molecular weight increase of the polymer. Furthermore, comparative example 9-5, which uses comparative FM-9 containing an additive (B-2) without the compound represented by general formula (2), has deteriorated crosslinking reactivity of the polymer (A), so it is speculated that the solvent resistance is not ideal.

[0338] Flatness

[0339] The aforementioned filler film forming materials (FM-1 to 4, and comparative FM-3 to 11) for suppressing semiconductor substrate pattern collapse were respectively coated on patterns with large isolated trenches. Figure 4 On a substrate 18 (SiO2 wafer substrate) with a trench width of 10 μm and a trench depth of 0.10 μm, a filling film 19 was formed by baking at 250°C for 60 seconds. The height difference between the trench and non-trench portions of the filling film was then observed using an NX10 atomic force microscope (AFM) manufactured by PARK SYSTEMS. Figure 4 (delta in (X)). The results are shown in Table 10. In this evaluation, the smaller the height difference, the better the planarization characteristics. Furthermore, in this evaluation, a trench pattern with a depth of 0.10 μm was planarized using a filler film forming material with a typical film thickness of about 0.2 μm for suppressing semiconductor substrate pattern collapse. This was a strict evaluation condition to assess the quality of the planarization characteristics. Comparative Examples 1-6 to 2-6 did not have filler films formed, so their planarization was not evaluated.

[0340] [Table 10]

[0341]

[0342] As shown in Table 10, Examples 1-6 to 4-6, which used the filler film forming material (FM-1 to 4) for suppressing semiconductor substrate pattern collapse of the present invention, showed a smaller height difference between the organic film in the trench portion and the non-trench portion, and superior planarization characteristics, compared to Comparative Examples 3-6 to 11-6, which used the comparative filler film forming material (FM-3 to 11) for suppressing semiconductor substrate pattern collapse. The reason for the excellent planarity of the filler film forming material for suppressing semiconductor substrate pattern collapse of the present invention is presumably due to (A) the wide molecular weight dispersion of the polymer having the structural unit represented by the above general formula (1), resulting in excellent thermal fluidity during coating and heat treatment. Furthermore, it is presumed that the residual solvent removal promoter having (B) the compound represented by the above general formula (2) has a small molecular weight and low viscosity, thus improving fluidity during coating. By using a polymer (A-3) having the structural unit represented by general formula (3) and a high-boiling-point solvent (C-2), the planarity can be further improved.

[0343] [Pattern formation test after embossing and pattern collapse inhibition test after filler removal]

[0344] The aforementioned filler film forming materials (FM-1 to 4, comparative FM-3 to 11) for suppressing pattern collapse of semiconductor substrates are coated on the semiconductor substrate C and baked at 250°C for 60 seconds to form a filler film with a thickness of 200 nm as the lower resist film. A silicon-containing resist intermediate film is coated on it and baked at 200°C for 60 seconds to form an anti-reflection film with a thickness of 35 nm. An ArF monolayer resist of the upper resist film material is coated on it and baked at 105°C for 60 seconds to form a photoresist film (upper resist film) with a thickness of 100 nm. A semiconductor substrate C has a line and spacing pattern with an average line width of 30 nm and an average pitch of 45 nm between each line. However, a new pattern is formed by transferring a circuit pattern formed by an upper resist film to the main body where the pattern is not formed. This is to evaluate the pattern transferability of the filler film forming material used to suppress pattern collapse of the semiconductor substrate as a lower resist film and the pattern collapse suppression capability after the filler film is removed.

[0345] For silicon-containing photoresist interlayer films, the silicon-containing polymer and acid generator PAG1 shown below are dissolved in an organic solvent containing 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M) in the proportions shown in Table 11, and filtered through a fluoropolymer filter with a pore size of 0.1 μm to prepare silicon-containing photoresist interlayer film materials.

[0346] [Chemistry 27]

[0347]

[0348] [Table 11]

[0349]

[0350] PGEE: Propylene Glycol Ethyl Ether

[0351] The resist polymer, acid generator PAG2, and quencher shown below were dissolved in an organic solvent containing 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M) according to the proportions shown in Table 12. The solution was filtered through a fluoropolymer filter with a pore size of 0.1 μm to prepare the upper layer of the resist membrane material (resist membrane material for ArF).

[0352] [Table 12]

[0353]

[0354] Anti-corrosion polymer

[0355] Molecular weight (Mw) = 7,500

[0356] Dispersion (Mw / Mn) = 1.9

[0357] [Chemistry 28]

[0358]

[0359] [Chemistry 29]

[0360]

[0361] Then, the image was exposed using an ArF immersion exposure apparatus (Nikon; NSR-S610C, NA 1.30, σ 0.98 / 0.65, 35-degree dipole s-polarized illumination, 6% half-step phase shift mask), and baked at 100°C for 60 seconds (PEB). It was then developed for 30 seconds with a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution to obtain a 1:1 line and spacing pattern of 60 nm.

[0362] Then, using the Telius etching apparatus manufactured by Tokyo Powertech Co., Ltd., dry etching was performed, using the aforementioned resist pattern as a mask, to transfer the pattern onto the silicon-containing resist intermediate film. Again, using dry etching, the patterned silicon-containing resist intermediate film was used as a mask to transfer the pattern onto the filler film, and the patterned filler film was used as a mask to transfer the pattern onto the semiconductor substrate C.

[0363] The etching conditions are shown below.

[0364] Transfer conditions for silicon resist interlayer films

[0365]

[0366]

[0367] For the transfer conditions of the filler film

[0368] Transfer conditions on semiconductor substrate C

[0369] Conditions for removing the filler film from the semiconductor substrate C

[0370]

[0371] The semiconductor substrate C, after the aforementioned filler film was removed, was then cut, and the pattern cross-section was observed using an electron microscope (S-4700) manufactured by Hitachi, Ltd. The pattern shape of the newly created Pattern-B, transferred from the resist overlayer film, and the pattern collapse suppression performance of Pattern-A already formed on the semiconductor substrate C were evaluated. Regarding the pattern collapse suppression performance of the semiconductor substrate, a score of "A" (Excellent) was given when the proportion of uncollapsed and remaining lines exceeded 90%, a score of "B" (Good) was given when the proportion of uncollapsed and remaining lines exceeded 70% but was less than 90%, and a score of "C" (Poor) was given when the proportion of uncollapsed and remaining lines was less than 70%. The results are shown in Table 13.

[0372] [Table 13]

[0373]

[0374] The filler film forming materials (FM-1 to 4) for suppressing pattern collapse of semiconductor substrates of the present invention not only have excellent solvent resistance, but also excellent filling and flatness. Therefore, the upper resist pattern is finally well transferred to the main body of the semiconductor substrate C, and the newly formed pattern (Pattern-A) is different from the original pattern (Pattern-B) formed on the semiconductor substrate C.

[0375] On the other hand, comparative examples 3-7 and 5-7 of comparative FM-3 and FM-5, which used comparative FM-8, which used comparative FM-8, which used an excess of the residual solvent eliminator (B), and comparative example 9-7 of comparative FM-9, which used an additive (B-2) containing a compound not represented by general formula (2) in terms of the residual solvent eliminator (B), were found to have deteriorated film thickness uniformity and flatness, resulting in pattern collapse observed in Pattern-B.

[0376] Comparative Examples 4-7, which used Comparative FM-4 containing an acid-generating agent, showed significant damage to flatness due to bending of the substrate pattern during heat treatment, resulting in significant pattern collapse. Furthermore, Comparative Examples 6-7 and 7-7, which used Comparative FM-6 and Comparative FM-7 containing a polymer (A-5) with a narrow molecular weight dispersion (Mw / Mn) and poor flowability, showed significant deterioration in flatness due to the filler film not reaching the bottom of the pattern, suggesting pattern collapse. Comparative Example 10-7, which used Comparative FM-10 containing a polymer (A-3), showed partial peeling and disappearance of the pattern. This is presumably due to the high hydrophobicity of the polymer and low adhesion between the filler film and the semiconductor substrate pattern. Moreover, Comparative Example 11-1, which used a polymer (A-6) without structural units represented by general formula (1), showed pattern distortion. This is presumably due to deterioration in crosslinking density. Regarding the pattern collapse suppression after the filler film of Pattern-A is removed, the results are the same as those of Examples 1-3 to 4-3 and Comparative Examples 1-3 to 11-3.

[0377] As can be understood from the above, the filler film forming material for suppressing pattern collapse of semiconductor substrates according to the present invention has excellent film-forming properties and film thickness uniformity, as well as excellent filling properties for high aspect ratio patterns. Therefore, it is extremely useful as a filler film for suppressing pattern collapse in the cleaning and drying steps of fine semiconductor substrate patterns. Furthermore, if the processing method of the present invention uses this material, it can achieve a process where the amount of metal impurities on the surface of the semiconductor substrate after the filler film is removed is minimal. In addition, the aforementioned filler film has excellent solvent resistance and flatness, so it is also useful as a lower layer film in multilayer photoresist treatment, enabling the formation of new fine patterns with high precision on semiconductor substrates with already formed high aspect ratio patterns.

[0378] Furthermore, the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and those that have substantially the same structure and perform the same effect as the technical concept described in the claims of the present invention are all included within the technical scope of the present invention.

[0379] Explanation of reference numerals in the attached figures

[0380] 1: Patterned semiconductor substrate

[0381] 1a: Semiconductor substrate after filler film removal

[0382] 2: Cleaning solution or rinsing solution

[0383] 3: Filler membrane

[0384] 3a: Hardened filler membrane

[0385] 4: Semiconductor substrates with high aspect ratio patterns (Pattern-A)

[0386] 4a: Semiconductor substrate pattern (after Pattern-B formation)

[0387] 5: Filler membrane

[0388] 5a: Hardened filler membrane

[0389] 5b: Filler film pattern

[0390] 6: Silicon-containing photoresist interlayer

[0391] 6a: Pattern of silicon-containing photoresist interlayer

[0392] 7: Top layer of resist film

[0393] 7a: Circuit diagram

[0394] 8: Semiconductor substrates with high aspect ratio patterns

[0395] 8a: Semiconductor substrate pattern collapses after drying

[0396] 9: Cleaning solution or rinsing solution

[0397] 10: Semiconductor substrates with high aspect ratio patterns

[0398] 10a: Pattern collapse of a semiconductor substrate after removal of a porous filling film.

[0399] 11: Filler membrane

[0400] 11a: Hardened filled membrane containing pores

[0401] 12: Porosity

[0402] 13: Semiconductor substrates with high aspect ratio patterns

[0403] 13a: Pattern shape bent due to thermal shrinkage of the filler film

[0404] 13b: Pattern collapse of semiconductor substrate after removal of porous filler film

[0405] 14: Filler membrane

[0406] 14a: Hardened filled membrane containing pores

[0407] 15: Semiconductor substrates with high aspect ratio patterns

[0408] 15a: Substrate pattern collapse after removal of filler film containing cracks

[0409] 16: Filler membrane

[0410] 16a: Hardened filler membrane containing cracks

[0411] 17: Crack

[0412] 18: Substrate with a large isolated trench pattern

[0413] 19: Filler membrane

[0414] delta: The difference in membrane thickness between the trench section and the non-trench section.

Claims

1. A filler film forming material for suppressing pattern collapse on a semiconductor substrate, characterized in that: The mixture contains (A) a polymer having a structural unit represented by the following general formula (1), (B) a residual solvent removal accelerator containing a compound represented by the following general formula (2), and (C) an organic solvent. The ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polymer (A) obtained by gel permeation chromatography is 2.50 ≤ Mw / Mn ≤ 9.

00. The content of the residual solvent removal accelerator in (B) is 0.1 to 40 parts by mass relative to 100 parts by mass of the polymer in (A). And it does not contain acid-generating agents or acids. In this general formula (1), R 01 X is a monovalent organic group, either saturated or unsaturated, with 1 to 30 carbon atoms; m is an integer from 0 to 5; n is an integer from 1 to 6; m+n is an integer between 1 and 6; and p is 0 or 1. In this general formula (2), Q is a single bond or a q-valent hydrocarbon group with 1 to 20 carbon atoms, and R 02 It can be a hydrogen atom or a methyl group, and q is an integer from 1 to 5.

2. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to claim 1, wherein, In addition to the structural unit of general formula (1), polymer (A) also has the structural unit represented by the following general formula (3). In this general formula (3), R 03 It is a monovalent organic group with 1 to 30 carbon atoms, either saturated or unsaturated, where m is an integer from 0 to 5, n is an integer from 1 to 6, m+n is an integer between 1 and 6, p is 0 or 1, and R 01 Synonymous with X and the aforementioned.

3. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to claim 2, in, In this general formula (3), R 03 It is an alkyl group having 1 to 30 carbon atoms, or any of the structures represented by the following general formula (4). In this general formula (4), * represents the bonding site to the oxygen atom, R A R is a divalent organic group with 1 to 10 carbon atoms that can also be substituted. B It is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms that can be substituted.

4. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to claim 2 or 3, wherein, When the proportion of general formula (1) is a and the proportion of general formula (3) is b, the content of general formula (3) conforms to the relationship a+b=100 and b≤90.

5. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to any one of claims 1 to 3, wherein, This (C) organic solvent contains a high-boiling-point solvent.

6. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to claim 5, wherein, The high-boiling-point solvent is one or more organic solvents with a boiling point of 180°C or higher.

7. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to any one of claims 1 to 3, wherein, The filler film forming material used to suppress pattern collapse on semiconductor substrates contains (D) surfactant.

8. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to any one of claims 1 to 3, wherein, The amount of metal impurities in the filler film forming material used to suppress pattern collapse of semiconductor substrates is less than 3 ppb by mass.

9. The filler film forming material for suppressing pattern collapse of a semiconductor substrate according to claim 8, wherein, The metals are Na, Mg, K, Ca, Mn, Fe, Ni, Cu, and Ti.

10. A method for processing a semiconductor substrate, comprising the following steps: A filling film is formed by filling a semiconductor substrate with an aspect ratio of 5 or more on a surface with an uneven pattern formed thereon using a filling film forming material for suppressing pattern collapse of a semiconductor substrate according to any one of claims 1 to 9; and Remove the filler membrane.

11. A method for processing a semiconductor substrate, comprising a method for drying a semiconductor substrate on which a raised or recessed pattern has been formed on its surface, characterized in that: The semiconductor substrate is dried by including the following steps. (1) The step of cleaning the patterned semiconductor substrate with a cleaning solution, or the step of cleaning the patterned semiconductor substrate with a cleaning solution and then replacing it with a rinsing solution, (2) The step of using a filling film forming material for suppressing semiconductor substrate pattern collapse according to any one of claims 1 to 9 to replace the aforementioned cleaning solution or rinsing solution and filling the filling film. (3) The step of hardening the filler film by heat treatment at a temperature between 100°C and 600°C for 10 to 600 seconds. (4) The step of removing the hardened filler film from the semiconductor substrate by dry etching.

12. A method for processing a semiconductor substrate, This method involves drying a semiconductor substrate with an existing raised and recessed pattern on its surface while simultaneously performing a process to form a raised and recessed pattern on the semiconductor substrate that differs from the original raised and recessed pattern. Includes the following steps: (1) The step of cleaning the patterned semiconductor substrate with a cleaning solution, or the step of cleaning the patterned semiconductor substrate with a cleaning solution and then replacing it with a rinsing solution. (2) The step of using a filling film forming material for suppressing semiconductor substrate pattern collapse according to any one of claims 1 to 9 to replace the aforementioned cleaning solution or rinsing solution and filling the filling film. (3) The step of hardening the filler film by heat treatment at a temperature between 100°C and 600°C for 10 to 600 seconds. (4) The step of forming a silicon-containing photoresist interlayer film on the hardened filler film using a silicon-containing photoresist interlayer film material. (5) The step of forming an upper resist film on the silicon-containing photoresist intermediate film using a photoresist composition. (6) The step of forming a circuit pattern on the upper layer of the resist film. (7) Using the upper resist film with the circuit pattern as a mask, the step of etching to transfer the pattern to the silicon-containing resist intermediate film. (8) Using the silicon-containing resist intermediate film with the transferred pattern as a mask, the step of etching to transfer the pattern onto the hardened filler film. (9) Using a hardened filler film with a transferred pattern as a mask, etching a semiconductor substrate on which a raised and recessed pattern has been formed to form a raised and recessed pattern different from the original raised and recessed pattern. (10) The step of removing the hardened filler film from the semiconductor substrate by dry etching.

13. The method for processing a semiconductor substrate according to claim 11 or 12, wherein, The metallic impurities on the surface of the semiconductor substrate after the hardened filler film was removed were 2.0 × 10E. ＋10 atoms / cm 2 the following.

14. The method for processing a semiconductor substrate according to claim 11 or 12, wherein, The cleaning solution or rinsing solution is a liquid containing one or more of water, water-soluble alcohol, and fluorine compounds.

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