Sublimation film forming composition and method for manufacturing a substrate

Abstract

The sublimation film-forming composition of the present application contains a sublimation substance and a solvent having a saturated solubility of the sublimation substance of greater than 10 mass %.

Description

TECHNICAL FIELD

[0001] The present application relates to a sublimation film forming composition and a manufacturing method of a substrate. BACKGROUND

[0002] Up to now, various developments have been made on manufacturing processes of substrates having a concavo-convex structure. As such a technology, for example, the technology described in Patent Literature 1 is known.

[0003] Patent Literature 1 describes a substrate drying method including a sublimation substance filling step of supplying a solution of a sublimation substance to a substrate having a pattern of a concavo-convex structure on a surface thereof to fill the solution in a concave portion of the pattern; a solvent drying step of drying a solvent in the solution to fill the concave portion of the pattern with the sublimation substance in a solid state; and a sublimation substance removing step of heating the substrate to a temperature higher than a sublimation temperature of the sublimation substance to remove the sublimation substance from the substrate (claim 1 of Patent Literature 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Publication No. 2012-243869 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, as a result of the research by the present inventors, it has been found that the solution of the sublimation substance described in Patent Literature 1 has room for improvement in terms of manufacturing stability of the substrate.

[0009] SOLUTION TO PROBLEM

[0010] As a result of further research by the present inventors, it has been found that even in the case of using a solution containing a sublimation substance and a solvent, there is a concern that pattern collapse occurs in a concavo-convex structure on a substrate in a large amount.

[0011] As a result of further research by the present inventors based on this insight, it has been found that by appropriately selecting a solvent having a high solvency and a high volatility for a sublimation substance or appropriately combining two or more kinds of solvents in a sublimation film forming composition containing a sublimation substance and a solvent, it is possible to suppress the occurrence of pattern collapse and improve the manufacturing stability of a substrate, thereby completing the present application.

[0012] According to the present application, it is possible to provide a sublimation film forming composition containing:

[0013] a sublimation substance; and

[0014] Solvent A1, which has a saturation solubility of the aforementioned sublimable substance of more than 10 mass% and a boiling point of 5°C or more lower than the boiling point of the aforementioned sublimable substance at 1 atm.

[0015] According to the present application, it is possible to provide a sublimation film forming composition, which is a sublimation film forming composition containing a sublimable substance, comprising:

[0016] Solvent A2, which has a saturation solubility of the aforementioned sublimable substance of more than 10 mass%; and

[0017] Solvent B2, which has a content in the sublimation film forming composition of more than the content of the aforementioned solvent A2, a boiling point of less than the boiling point of the aforementioned sublimable substance at 1 atm and less than the boiling point of the aforementioned solvent A2.

[0018] Further, according to the present application, it is possible to provide a method for manufacturing a substrate, comprising:

[0019] a step of preparing a substrate having a surface with a concavo-convex structure;

[0020] a step of supplying the aforementioned surface with a sublimation film forming composition containing a sublimable substance;

[0021] a step of solidifying the aforementioned sublimation film forming composition to form a sublimation film on the aforementioned surface; and

[0022] a step of sublimating the aforementioned sublimable substance to remove the aforementioned sublimation film,

[0023] The sublimation film forming composition containing the aforementioned sublimable substance is the aforementioned sublimation film forming composition.

[0024] Effects of the Invention

[0025] According to the present application, it is possible to provide a sublimation film forming composition and a method for manufacturing a substrate, which are excellent in manufacturing stability of a substrate. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a process cross-sectional view in an example of a manufacturing process of a substrate.

[0027] Figure 2 is an SEM image of a substrate surface in Example 1.

[0028] Figure 3 is an SEM image of a substrate surface in Example 3.

[0029] Figure 4 is an SEM image of a substrate surface in Example 5.

[0030] Figure 5is an SEM image of the surface of the substrate in Example 21.

[0031] Figure 6 is an SEM image of the surface of the substrate in Example 22.

[0032] Figure 7 is an SEM image of the surface of the substrate in Comparative Example 1. DETAILED DESCRIPTION

[0033] The sublimation film-forming composition of the present embodiment is summarized.

[0034] The sublimation film-forming composition of the first embodiment contains: a sublimation substance; and, a solvent Al whose saturated solubility of the sublimation substance is greater than 10 mass% and whose boiling point is lower than the boiling point of the sublimation substance at 1 atm by 5°C or more.

[0035] The sublimation film-forming composition of the second embodiment contains: a sublimation substance; a solvent A2 whose saturated solubility of the sublimation substance is greater than 10 mass%; and, a solvent B2 whose content in the sublimation film-forming composition is greater than that of the solvent A2, whose boiling point is lower than the boiling point of the aforementioned sublimation substance at 1 atm and lower than the boiling point of the solvent A2.

[0036] Such a sublimation film-forming composition of the present embodiment can be suitably used in a manufacturing process of a substrate having a concavo-convex structure on the surface, and can suppress pattern collapse in the concavo-convex structure of the substrate.

[0037] Figure 1 (a) to (c) of FIG. 1 are process cross-sectional views showing an example of a manufacturing process of a substrate using a sublimation film-forming composition.

[0038] Figure 1 (a) of FIG. 1 shows a process of supplying a sublimation film-forming composition 30 to the surface of a substrate 10, and filling the sublimation film-forming composition 30 in a concave portion 24 in a concavo-convex structure 20, Figure 1 (b) of FIG. 1 shows a process of solidifying the sublimation film-forming composition 30 to form a sublimation film 50, Figure 1 (c) of FIG. 1 shows a process of sublimating the sublimation substance to remove the sublimation film 50.

[0039] An example is shown to explain the manufacturing of a semiconductor chip. In this manufacturing process, a fine concavo-convex pattern is formed on the surface of a substrate (wafer) through film formation, photolithography, or etching, and the like, and then, in order to clean the wafer surface, a wet treatment such as a cleaning process using water, an organic solvent, or the like is performed, and in order to remove a liquid such as a cleaning liquid or a rinsing liquid attached to the wafer due to the wet treatment, a drying process is also performed.

[0040] In this drying process, it is known that deformation and collapse of the fine concavo-convex pattern easily occur in a semiconductor substrate having a fine concavo-convex pattern.

[0041] In order to perform drying of a substrate having a concavo-convex pattern using a sublimable substance, a process of replacing a residual liquid remaining in the concavo-convex pattern with a treatment liquid containing a sublimable substance is generally performed.

[0042] According to the present inventors' insight, it was found that by appropriately selecting a solvent having a higher solubility and higher volatility of a sublimable substance, or by appropriately combining two or more solvents in a sublimable film-forming composition containing a sublimable substance and a solvent, it is possible to suppress the occurrence of pattern collapse in the concavo-convex structure of a substrate when used in a manufacturing process of a substrate having a concavo-convex structure.

[0043] As shown in the first embodiment, a solvent Al having a moderate solubility of a sublimable substance and a moderate volatility can be used. As shown in the second embodiment, a solvent A2 having a moderate solubility of a sublimable film and a solvent B2 having a moderate volatility can be used.

[0044] The detailed mechanism is not certain, but it is believed that by using a high-volatility solvent (solvent Al, solvent B2) having a higher volatility than the sublimable substance, the film-forming ability is improved, and by using a high-solubility solvent (solvent Al, solvent A2) having a higher solubility of the sublimable substance, the excessive precipitation of the sublimable substance at the initial stage is suppressed, and thus the pattern collapse starting from the sublimable substance precipitated at the initial stage is suppressed.

[0045] Furthermore, in the technical field of substrates having fine concavo-convex structures such as semiconductor wafers, pattern collapse is generally known to mean a state in which patterns in a specified range collapse in random directions, i.e., so-called planar collapse.

[0046] However, it is known that there is a linear collapse that is different from the planar collapse.

[0047] The so-called linear collapse basically means a state in which patterns collapse continuously in a specified direction. The linear collapse is sometimes formed in a manner of surrounding a specific region in which no pattern collapse occurs. Even if the planar collapse is suppressed and the pattern collapse rate is reduced, there is a concern that the linear collapse will occur.

[0048] According to the present inventors' insight, it was found that by using a solvent Al, a solvent A2 having a higher solubility of a sublimable substance and / or by using a sublimable substance having a lower heat of condensation, it is possible to suppress the linear collapse even in the pattern collapse.

[0049] The exact mechanism is uncertain, but it is thought that strip-like collapse occurs due to stress at the grain boundaries of the sublimable film. Therefore, it is believed that the aforementioned strip-like collapse can be suppressed by using a solvent with high solubility to inhibit local crystallization based on the initial precipitation of the sublimable material, and by using a sublimable material with low heat of solidification to reduce crystallinity.

[0050] The sublimation film forming composition of this embodiment is suitable for use in the process of drying the uneven pattern in the manufacturing process of a substrate with an uneven structure.

[0051] The sublimable material can be a substance that disappears entirely upon a specified heat treatment, or a substance that disappears after standing at 23°C under 1 atmosphere. In the substrate manufacturing process, the sublimable film is not a permanent film that remains on the substrate, but rather serves as a sacrificial film that will be removed in subsequent processes. Therefore, the sublimable film forming composition can be used as a composition for forming a sublimable sacrificial film.

[0052] The sublimation film-forming composition of this embodiment is described in detail below.

[0053] (Sublimable substances)

[0054] The sublimation film-forming composition contains one or more sublimation substances.

[0055] In this specification, a sublimable substance is a substance that has a vapor pressure in the solid state.

[0056] Sublimable substances can be used in principle as long as they are solid at a specific temperature and have vapor pressure.

[0057] The lower limit of the solidification point of the sublimable material is, for example, 5°C or higher at 1 atmosphere, preferably 20°C or higher, and more preferably 50°C or higher. Therefore, in the case of its application in substrate manufacturing methods, the solidification of the sublimable material does not need to be performed at extremely low temperatures, which improves the manufacturing stability of the semiconductor substrate.

[0058] On the other hand, the upper limit of the freezing point of the sublimable material is, for example, 220°C or below at 1 atmosphere, preferably 200°C or below, and more preferably 180°C or below. Therefore, in the case of its application in the manufacturing method of a substrate, the sublimation of the sublimable material does not require extremely high temperature processing, which improves the manufacturing stability of the semiconductor substrate.

[0059] The lower limit of the heat of solidification of sublimable substances is not particularly limited, and can be, for example, 1 J / g or more, preferably 5 J / g or more, and more preferably 10 J / g or more.

[0060] On the other hand, the upper limit of the heat of solidification of the sublimable substance is 200 J / g or less, preferably 100 J / g or less, and more preferably 50 J / g or less. This can suppress the occurrence of strip-like collapse.

[0061] The sublimable substance can also be composed in a manner that substantially does not contain any non-volatile substances that would become residues after sublimation. Non-volatile substances can be removed from the sublimable substance by separation methods such as sublimation purification or distillation. "Substantially does not contain" means that it preferably comprises 1% or less by mass in 100% by mass of the sublimable substance, more preferably 0.5% or less by mass, or where unavoidable contamination is permissible.

[0062] The lower limit of the boiling point of the sublimable substance is, for example, 60°C or higher at 1 atmosphere, preferably 100°C or higher, and more preferably 110°C or higher. This makes it possible to stably manufacture a sublimable film containing the sublimable substance.

[0063] On the other hand, the upper limit of the boiling point of the sublimable substance is, for example, below 300°C at 1 atmosphere, preferably below 280°C, and more preferably below 250°C. This makes the purification of the sublimable substance easier. Furthermore, in ambient temperature and pressure manufacturing processes, the sublimation of the sublimable substance becomes easier, improving manufacturing efficiency.

[0064] The boiling point or sublimation point of a substance containing multiple sublimable substances shall be the boiling point or sublimation point of the component with the highest content (mass%) among the components contained in the sublimable substance (wherein, if there are more than two components with the highest content, the boiling point or sublimation point of the component with the highest temperature shall be used).

[0065] The boiling point of sublimable substances is defined as the initial boiling point as specified in JIS K 2254:2018 (ISO 3405).

[0066] Furthermore, when the sublimation point is conventionally used depending on the substance, the sublimation point is used.

[0067] Furthermore, the freezing point of sublimable substances is determined using DSC at a rate of -10°C / min. For sublimable substances containing multiple components, the freezing point is determined by the component with the highest content (mass%) among the components contained in the sublimable substance (where, if there are two or more components with the highest content, the freezing point of the component with the higher content is used).

[0068] The temperature range in which the sublimable substance is a solid and has a vapor pressure (hereinafter also referred to as the "sublimation temperature range") can be, for example, 10°C or higher. Therefore, even when used in an environment of 20 to 25°C, which is the normal room temperature of a cleanroom, the sublimable substance can be solidified by cooling caused by the heat of vaporization of the solvent in the sublimable film forming composition.

[0069] Furthermore, if the sublimation temperature range is within 20 to 25°C, then sublimation-promoting treatments such as heating or depressurization are not required. The sublimable material can be sublimated more easily under the conditions of current substrate manufacturing processes to remove the sublimable film.

[0070] Furthermore, the vapor pressure at the defined sublimation temperature zone is, for example, 10 Pa or more, preferably 50 Pa or more.

[0071] In this specification, unless otherwise specified, “~” indicates that both the upper and lower limits are included.

[0072] As a sublimation material, it is not limited as long as it can be used in substrate materials such as semiconductors, but examples include: non-halogen sublimation material S1 with a low heat of solidification, non-halogen sublimation material S2 with a high heat of solidification, sublimation material S3 with a small difference between its freezing point and boiling point, and halogen-containing sublimation material S4 containing halogen elements, etc. These can be used alone or in combination of two or more.

[0073] The heat of solidification of the non-halogenated sublimable substance S1 is preferably 50 J / g or less, more preferably 40 J / g or less. Since S1 tends to have a large difference between its freezing point and boiling point, it can be purified by distillation in liquid form. Using S1 can suppress the occurrence of strip collapse.

[0074] The heat of solidification of non-halogenated sublimable substance S2 is preferably greater than 50 J / g.

[0075] The difference between the freezing point and boiling point of the sublimable substance S3 is, for example, 50°C or less, preferably 40°C or less, and more preferably 30°C or less.

[0076] The halogenated sublimable substance S4 can also be a fluorinated sublimable substance containing fluorine as the halogen element.

[0077] From the perspective of suppressing pattern collapse, sublimation substances of S1 to S3 are suitable for use.

[0078] Examples of sublimable substances include: norbornene, norbornane, camphor, pyrazine, 2,3-dichloropyrazine, 2,6-dichloropyrazine, 2,6-dichloropyridine, tetrahydrodicyclopentadiene, dimethyl oxalate, isobornol, neopentyl alcohol, neopentyl glycol, and ethylene carbonate. Among these, neopentyl alcohol, camphor, pyrazine, tetrahydrodicyclopentadiene, dimethyl oxalate, isobornol, and ethylene carbonate may also be used. These can be used alone or in combination of two or more. Furthermore, in the presence of optical isomers, one or both can be used.

[0079] The lower limit of the content of the sublimable substance in the sublimable film-forming composition is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 0.8% by mass or more. This makes it easier to uniformly solidify the sublimable substance in the sublimable film-forming composition.

[0080] On the other hand, the upper limit of the content of the sublimable substance in the sublimable film-forming composition is, for example, 80% by mass or less, preferably 50% by mass or less, and more preferably 40% by mass or less. This makes it easier to obtain a cooling effect due to the heat of vaporization of the solvent and to promote the solidification of the sublimable substance, which is therefore preferred. Furthermore, it makes it easier to shorten the time required for sublimation (sublimation time), which is also preferred.

[0081] (solvent)

[0082] The sublimation film-forming composition of this embodiment includes solvent A, in which the saturation solubility of one or more sublimation substances is greater than 10% by mass. Solvent A is defined as including solvent A1 and solvent A2 as described above.

[0083] By using solvent A, which has the dissolving power of sublimable substances, the formation of solidified sublimable substances at the nozzle tip can be suppressed when the sublimable film forming composition is supplied to the substrate via a nozzle.

[0084] Saturated solubility can be determined based on the saturated concentration (mass%) of the sublimable substance dissolved in the solvent.

[0085] In cases involving multiple solvents, the saturated solubility is determined using the value specified for each solvent.

[0086] When the sublimable film-forming composition contains multiple sublimable substances, the saturation solubility is determined by the saturation concentration of the sublimable substance with the highest content (mass%) in the composition (wherein, if there are two or more sublimable substances with the highest content, the value of the highest saturation concentration is used).

[0087] The sublimable substance has a lower limit of saturated solubility relative to solvent A of more than 10% by mass, preferably more than 30% by mass, more preferably more than 40% by mass, further preferably more than 50% by mass, and even more preferably more than 60% by mass. This reduces the pattern collapse rate.

[0088] On the other hand, the upper limit of the saturated solubility of the sublimable substance relative to solvent A can be, for example, 99% by mass or less, or 95% by mass or less.

[0089] Furthermore, the sublimation film-forming composition can also use solvent A, which is compatible with residual liquid remaining on the substrate surface. This allows for efficient replacement of the residual liquid with the sublimation film-forming composition, enabling stable drying of the residual liquid.

[0090] As residual liquids, common solvents used in semiconductor cleaning processes can be listed, specifically: water, alcohols with 3 or fewer carbon atoms (e.g., methanol, 1-propanol, 2-propanol, etc.) or mixtures thereof.

[0091] The term "miscible" means that, at 25°C and 1 atmosphere, the amount of solvent dissolved in the cleaning process is, for example, 0.05 parts by mass or more relative to 1 part by mass of solvent A.

[0092] The sublimation film-forming composition of the first embodiment contains one or more solvents A1, wherein the saturated solubility of the sublimation substance in solvent A1 is greater than 10% by mass, and the boiling point is more than 5°C lower than the boiling point of the sublimation substance at 1 atmosphere.

[0093] Solvent A1 is a solvent selected from solvent A that has a boiling point that is more than 5°C lower than the boiling point of the sublimable substance at 1 atmosphere (1).

[0094] In condition (1), (the boiling point of the sublimable substance at 1 atmosphere - the boiling point of solvent A1) can be 5°C or higher, preferably 50°C or higher, more preferably 80°C or higher, and on the other hand, it can also be 200°C or lower, preferably 180°C or lower.

[0095] In this specification, the boiling points of each solvent in cases involving multiple solvents are used. In the case of an azeotropic solvent, the azeotropic point is used. In the case of a non-azeotropic solvent, the boiling point specified for each solvent is used.

[0096] It can be considered that in the sublimable film forming composition of the first embodiment, by including at least one such solvent A1, the solvent A1 with high solubility will inhibit the excessive initial precipitation of the sublimable substance, and the solvent A1, which is more volatile than the sublimable substance, can promote the film formation of the sublimable film (the solidification of the sublimable substance) through the heat of vaporization. Thus, after the sublimable film is formed and removed, in addition to reducing the pattern collapse rate, strip collapse can also be suppressed.

[0097] The sublimation film-forming composition of this embodiment may contain, in addition to solvent A, one or more solvents B with boiling points lower than the boiling point of the sublimation substance at one atmosphere. Solvent B is defined as including solvent B1 and solvent B2 as described above.

[0098] The sublimation film-forming composition of the first embodiment may also contain one or more of the above-mentioned solvents A1 and one or more of solvents B1 with boiling points lower than those of solvent A1.

[0099] Solvent B1 is a solvent with a boiling point lower than that of solvent A1 in solvent B, and the saturated solubility of its sublimable substance is not particularly limited; it can be used even if its saturated solubility is lower than that of solvent A1. The difference between the boiling point of solvent A1 and the boiling point of solvent B1 is, for example, 5°C or more, preferably 10°C or more, more preferably 15°C or more, and on the other hand, it can be 200°C or less, or 150°C or less.

[0100] The boiling point of solvent B1 is, for example, 15°C to 85°C, preferably 20°C to 80°C, and more preferably 25°C to 70°C.

[0101] The lower limit of the content of solvent A1 in the sublimation film-forming composition is, for example, 0.5% by mass or more, preferably 0.8% by mass or more, and more preferably 0.9% by mass or more.

[0102] Furthermore, in the sublimable film-forming composition, when solvent A1 is the main solvent component, the content of solvent A1 in the sublimable film-forming composition can be 50% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more. In this case, if other solvents are used, solvent B1 is preferred. In this case, the content of solvent A1 in the sublimable film-forming composition can be made greater than the value of solvent B1.

[0103] On the other hand, regarding the upper limit of the content of solvent A1, when the solvent of the sublimable film-forming composition substantially contains only solvent A1 and / or when solvent A1 is defined as the main component of the solvent in the sublimable film-forming composition, it is, for example, 99.9% by mass or less, preferably 99.5% by mass or less, and more preferably 99.2% by mass or less. Furthermore, when the sublimable film-forming composition contains both solvent A1 and solvent B1 and A1 is not defined as the main component of the solvent, the content of solvent A1 in the sublimable film-forming composition, for example, can be made less than 50% by mass, preferably 30% by mass or less, and more preferably 15% by mass or less.

[0104] The sublimation film-forming composition of the second embodiment includes one or more solvents A2 and one or more solvents B2, wherein the saturated solubility of the sublimation substance in solvent A2 is greater than 10% by mass; the content of solvent B2 in the sublimation film-forming composition is greater than the content of solvent A2, and the boiling point is less than the boiling point of the aforementioned sublimation substance at 1 atmosphere and less than the boiling point of solvent A2.

[0105] Solvent A2 is selected from the solvents A mentioned above. The boiling point of the sublimable substance at 1 atmosphere – the boiling point of solvent A2 – can be 0°C, or 0°C or higher but less than 5°C, or 5°C or higher but less than 200°C. Furthermore, from the viewpoint of easily solidifying the sublimable substance, for example, 0°C or higher but less than 200°C is preferred, and 5°C or higher but less than 200°C is even more preferred.

[0106] Solvent B2 is a solvent that can promote the formation of sublimation films by evaporating earlier than solvent A2. As long as the boiling point of the solvent is lower than that of solvent A2 and the boiling point of the sublimation substance, the saturated solubility of the sublimation substance is not particularly limited. It can be used even if the saturated solubility of the sublimation substance relative to solvent A2 is lower than that of the aforementioned sublimation substance.

[0107] In this composition, the content of solvent B2 in the sublimable film-forming composition is a higher value than that of solvent A2. It is also preferable to include solvent B2 as a main component in the sublimable film-forming composition. The lower limit of the content of solvent B2 in the sublimable film-forming composition as a main component is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. The upper limit of the content of solvent B2 may also be, for example, 99.8% by mass or less, 99.5% by mass or less, or 99% by mass or less.

[0108] In a sublimable film-forming composition containing solvent B2 as the main component, the content of solvent A2 is, for example, 0.1% to 30% by mass, preferably 0.5% to 10% by mass.

[0109] In the sublimation film-forming composition of the second embodiment, by comprising at least one of solvents A2 and B2 respectively, solvent B2 relatively evaporates, thereby promoting the formation of the sublimation film (solidification of the sublimation substance) through heat of vaporization. At this time, the sublimation substance and solvent A2 remain, but since solvent A2 can dissolve the sublimation substance in these residues, it is considered that the excessive initial precipitation of the sublimation substance can be suppressed. Therefore, after the sublimation film is formed and removed, not only can the pattern collapse rate be reduced, but strip collapse can also be suppressed. Furthermore, the sublimation film-forming composition of this second embodiment is known to have a particular tendency to reduce the pattern collapse rate in the embodiments described later.

[0110] By including solvent B2 as the main component in the sublimation film forming composition of the second embodiment, the film forming time of the sublimation film can be reduced, and the manufacturing cost of the substrate can also be suppressed.

[0111] Furthermore, the difference between the boiling point of solvent A2 and the boiling point of solvent B2 is not particularly limited, as long as solvent A2 can remain after solvent B2 evaporates. For example, it can be 5°C or higher, preferably 10°C or higher, more preferably 15°C or higher, and even more preferably greater than 20°C. On the other hand, it can be 200°C or lower, or 150°C or lower.

[0112] The upper limit of the boiling point of solvent B2 is, for example, below 85°C, preferably below 80°C, and more preferably below 70°C.

[0113] On the other hand, the lower limit of the boiling point of solvent B2 may be, for example, 15°C or higher, preferably 20°C or higher, and more preferably 25°C or higher.

[0114] In the case where the first embodiment includes two or more solvents A1, as an example, the second and subsequent solvents A1 may be selected from solvents in which the saturated solubility of the sublimable substance relative to the solvent A1 is 40% by mass or more and the boiling point is 200°C or less, or preferably from solvents in which the saturated solubility of the sublimable substance is 75% by mass or more and the boiling point is 180°C or less.

[0115] In the second embodiment, when two or more solvents A2 and / or B2 are included, as an example, the second or subsequent solvent A2 may be selected from a solvent in which the saturated solubility of the sublimable substance relative to the solvent A2 is 40% by mass or more and the boiling point is below the boiling point of the sublimable substance. It may also preferably be selected from a solvent in which the saturated solubility of the sublimable substance is 50% by mass or more and the boiling point is 210°C or less. It may also preferably be selected from a solvent in which the saturated solubility of the sublimable substance is 60% by mass or more and the boiling point is 200°C or less. More preferably, it may also be selected from a solvent in which the saturated solubility of the sublimable substance is 75% by mass or more and the boiling point is 180°C or less.

[0116] Furthermore, when the solvent A2 contains two or more solvents A2 and one or more solvents B2, the solvent with the smaller boiling point difference among the solvents A2 is more likely to remain when solvent B2 evaporates, which is therefore preferable. The boiling point difference is not particularly limited as long as it allows solvent A2 to function effectively. For example, the difference between the highest and lowest boiling point of the two or more solvents A2 is preferably 20°C or less, more preferably 15°C or less, and even more preferably 10°C or less. That is, the difference in boiling point between the second or subsequent solvents A2 and the first solvent A1 can be, for example, 10°C or less, 15°C or less, or 20°C or less. Furthermore, in this case, the boiling point of solvent B2 is lower than the lowest boiling point of solvent A2.

[0117] Furthermore, the second and subsequent solvents B2 may also be selected from those with a boiling point of, for example, 83°C or below, preferably 80°C or below, and more preferably 70°C or below.

[0118] Solvents used in sublimation film-forming compositions include: hydrocarbons, ethers, alcohols, ketones, esters, sulfoxides, and nitrogen-containing compounds. These solvents may also have one or more halogen atoms, such as fluorine or chlorine, within their molecules. They can be used alone or in combination of two or more.

[0119] Hydrocarbons that can be used include, for example, alkanes or cycloalkanes with 4 to 10 carbon atoms, alkenes or cycloalkenes with 4 to 10 carbon atoms, and aromatic hydrocarbons with 6 to 10 carbon atoms.

[0120] Specific examples of hydrocarbons include: pentane, 3-methylpentane, hexane, heptane, octane, nonane, decane, isododecane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene (1233Z), trans-1-chloro-3,3,3-trifluoropropene (1233E), toluene, benzene, xylene, etc.

[0121] Ethers can be, for example, chain-like or cyclic ether compounds with 3 to 10 carbon atoms.

[0122] Specific examples of ethers include: tetrahydrofuran, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, tert-butyl methyl ether, dioxane, 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (Novec 7100), ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, etc.

[0123] Alcohols can be, for example, primary, secondary, and tertiary alcohols with 1 to 10 carbon atoms.

[0124] Specific examples of alcohols include: methanol, ethanol, 1-propanol, 2-propanol (IPA), 1-butanol, 2-butanol, cyclopentanol, cyclohexanol, 2-methyl-2-butanol, 4-methyl-2-pentanol, ethylene glycol, propylene glycol, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 1,3-propanediol, etc.

[0125] Ketones can be, for example, ketone compounds with 3 to 6 carbon atoms.

[0126] Specific examples of ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, and methyl butyl ketone.

[0127] Examples of esters include chain or cyclic ester compounds with 3 to 6 carbon atoms.

[0128] Specific examples of esters include: methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate, methyl lactate, ethyl lactate, ethyl acetoacetate, ethyl trifluoroacetate, γ-butyrolactone, ethylene glycol acetate, propylene glycol acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc.

[0129] Examples of sulfoxides include dimethyl sulfoxide, etc.

[0130] Examples of nitrogen-containing compounds include: formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, etc.

[0131] Based on the sublimation substance contained in the sublimation film forming composition, one or more solvents are selected from the above solvents as solvent A1, solvent A2, solvent B1 and solvent B2 respectively.

[0132] For solvents A1 and A2, from the viewpoint of balancing high solubility for sublimation agents and compatibility with water or alcohols with 3 or fewer carbon atoms as residual liquids remaining on the substrate surface, it is particularly preferred that they include at least one of the group consisting of ethers, alcohols, ketones, esters, and hydrocarbons having one or more halogen atoms such as fluorine or chlorine atoms in the molecule. Specific examples of these include: tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-butanol, acetone, methyl acetate, ethyl acetate, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, and trans-1-chloro-3,3,3-trifluoropropene, etc. Furthermore, the following can be preferably listed: methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, 2-methyl-2-butanol, acetone, methyl acetate, cis-1-chloro-3,3,3-trifluoropropene and trans-1-chloro-3,3,3-trifluoropropene, etc.

[0133] For solvents B1 and B2, from the viewpoint of balancing high volatility and compatibility with water or alcohols with 3 or fewer carbon atoms as residual liquids remaining on the substrate surface, it is preferable to include at least one selected from the group consisting of hydrocarbons, ethers, alcohols, ketones, and esters. Specific examples of these include: pentane, 3-methylpentane, hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, trans-1-chloro-3,3,3-trifluoropropene, toluene, benzene, xylene, diethyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, methyl acetate, and ethyl acetate, etc. Preferred examples include: pentane, hexane, cyclopentane, cyclohexane, methylcyclohexane, cis-1-chloro-3,3,3-trifluoropropene, trans-1-chloro-3,3,3-trifluoropropene, diethyl ether, tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, acetone, and methyl acetate.

[0134] (Other solvents)

[0135] The sublimation film forming composition may, to the extent that it does not impair the effects of the present invention, further include solvent C in addition to the above-mentioned solvents A1, A2, B1, and B2, for the purpose of adjusting the wettability to the substrate and / or the uneven pattern, or it may be configured in a manner that substantially does not contain solvent C in the sublimation film forming composition.

[0136] Solvent C can be exemplified by, for example, water, hydrocarbons, esters, ethers, ketones, sulfoxide solvents, alcohols, derivatives of polyols, nitrogen-containing compounds, etc., and refers to solvents that are not used as essential components as described above.

[0137] Examples of the aforementioned hydrocarbons include toluene, benzene, xylene, pentane, 3-methylpentane, hexane, heptane, octane, nonane, decane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene (1233Z), and trans-1-chloro-3,3,3-trifluoropropene (1233E). Examples of the aforementioned esters include... Examples of ethers include ethyl acetate, butyl acetate, methyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate, methyl lactate, ethyl lactate, ethyl acetoacetate, ethyl trifluoroacetate, and γ-butyrolactone. Examples of the above ethers include diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane, and 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (Novec). Examples of the above-mentioned ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, etc.; examples of the above-mentioned sulfoxide solvents include dimethyl sulfoxide, etc.; examples of the above-mentioned alcohols include methanol, ethanol, 1-propanol, 2-propanol, butanol, 4-methyl-2-butanol, ethylene glycol, 2-methyl-2-butanol, 4-methyl-2-pentanol, ethylene glycol, propylene glycol, 2,2,2-trifluoroethanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 1,3-propanediol, etc.; and derivatives of the above-mentioned polyols Examples of such compounds include diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, etc.; examples of the nitrogen-containing compounds mentioned above include formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, etc., and examples of solvents that are not solvents A1, A2, B1, B2 can be cited.

[0138] The lower limit of the total solvent content in the sublimable film-forming composition is, for example, 20% by mass or more, preferably 50% by mass or more, and more preferably 60% by mass or more. This makes it easier to obtain a cooling effect due to the heat of vaporization of the solvent, thus facilitating the solidification of the sublimable substance, and is therefore preferred.

[0139] On the other hand, the upper limit of the total solvent content in the sublimable film-forming composition is, for example, 99.9% by mass or less, preferably 99.5% by mass or less, and more preferably 99.2% by mass or less. This makes it easier for the sublimable material to solidify uniformly on the substrate, which is therefore preferable.

[0140] The sublimable film-forming composition is liquid, preferably a solution, at least when supplied to the substrate surface. From the viewpoint of easy and stable supply, it is preferable to be liquid (preferably a solution) at -15°C to 50°C, and more preferably liquid (preferably a solution) at 0°C to 40°C. Furthermore, from the viewpoint of simplifying the process by eliminating the need for heat preservation / heating devices for the discharge mechanism, it is preferable to be liquid (preferably a solution) at 20°C to 30°C.

[0141] Furthermore, from the viewpoint of facilitating handling (manufacturing, storage, transportation, etc.), it can be a liquid (preferably a solution) at -15°C to 50°C, and more preferably a liquid (preferably a solution) at 0°C to 40°C. Moreover, from the viewpoint of simplifying the construction of pipetting mechanisms, storage container insulation / heating devices, etc., it is more preferable to be a liquid (preferably a solution) at 20°C to 30°C.

[0142] (Substrate manufacturing method)

[0143] As an example of the substrate manufacturing method in this embodiment, such as Figure 1 As shown, it includes: a step of preparing a substrate 10 with a surface having an uneven structure 20; and a step of supplying a sublimable film forming composition 30 containing a sublimable substance to the surface. Figure 1 (a)); the process of solidifying the sublimation film forming composition 30 to form a sublimation film 50 on the surface. Figure 1 (b)); and, the process of sublimating the sublimable substance to remove the sublimable film 50 Figure 1 (c)).

[0144] As Figure 1 The sublimation film forming composition 30 containing a sublimation substance in (a) may use the sublimation film forming composition of this embodiment, or the sublimation film forming composition of the first embodiment or the second embodiment described above.

[0145] The sublimation film forming composition of this embodiment is used to suppress pattern collapse of the uneven structure 20 formed on the substrate 10.

[0146] The following details the method for manufacturing the substrate.

[0147] In the preparation process of the substrate 10 described above, the following method, which is an example of a method for forming a rough and uneven structure 20 on the surface of the substrate 10, may also be used.

[0148] First, after coating the wafer surface with a photoresist, the photoresist is exposed through a photoresist mask to remove either the exposed or unexposed photoresist, thereby creating a photoresist with the desired raised and recessed pattern. Alternatively, a photoresist with a raised and recessed pattern can be obtained by pressing a patterned mold onto the photoresist. Next, the wafer is etched. At this time, the substrate surface corresponding to the recessed portions of the photoresist pattern can be selectively etched. Finally, the photoresist is stripped off to obtain a wafer (substrate 10) with a raised and recessed structure 20 on its surface.

[0149] The wafer with the uneven structure 20 and the material of the uneven structure 20 are not particularly limited. As a wafer, various wafers can be used, such as silicon wafers, silicon carbide wafers, wafers composed of multiple components containing silicon, sapphire wafers, various compound semiconductor wafers, and plastic wafers. Furthermore, the material of the uneven structure 20 can also be silicon-based materials such as silicon oxide, silicon nitride, polycrystalline silicon, and monocrystalline silicon, metallic materials such as titanium nitride, tungsten, ruthenium, tantalum nitride, and tin, as well as materials combining these and photoresist materials.

[0150] Figure 1 (a) is a cross-sectional view showing an example of the raised pattern 20. For the pattern size in the cross-sectional structure (in the substrate thickness direction) of the raised pattern 20, at least one of its width and height, or for the pattern size in the three-dimensional structure (XYZ coordinates) of the raised pattern 20, at least one of its width (length in the X-axis direction), height (length in the Y-axis direction), and depth (length in the Z-axis direction), it can be, for example, 30 nm or less, 20 nm or less, or 10 nm or less. Even when using a substrate 10 having such a fine raised pattern 20, it becomes possible to reduce the pattern collapse rate by using the drying composition of this embodiment.

[0151] In addition, Figure 1 In the cross-sectional view, the inclination of the raised and recessed patterns 20 is parallel (non-intersecting) to the substrate thickness direction. However, the drying composition of this embodiment is suitable for use even when the inclination of the raised and recessed patterns 20 is not parallel to the substrate thickness direction. The aforementioned "non-parallel case" includes, for example, in... Figure 1 In the cross-sectional structure, there are cases where the inclination of the embossed pattern 20 is orthogonal to the thickness direction of the substrate, or where the inclination of the embossed pattern 20 intersects the thickness direction of the substrate (excluding orthogonal cases).

[0152] This sublimation film-forming composition is suitable for processing substrates 10, for example, having a pattern size of less than 30 nm, preferably less than 20 nm, with an uneven structure 20.

[0153] The lower limit of the aspect ratio of the protrusion 22 can be, for example, 3 or more, 5 or more, or 10 or more. Pattern collapse can be suppressed even in the concave-convex structure 20 of the protrusion 22, which has a fragile structure.

[0154] On the other hand, the aspect ratio of the protrusion 22 is not particularly limited and can be below 100.

[0155] The aspect ratio of the protrusion 22 is represented by the value obtained by dividing the height of the protrusion 22 by the width of the protrusion 22.

[0156] After the uneven structure 20 is formed, the surface of the substrate 10 is cleaned with a cleaning solution such as water or organic solvent (cleaning process).

[0157] After the cleaning process, such as Figure 1 As shown in (a), a liquid sublimation film-forming composition is supplied to the uneven structure 20 formed on the surface of the substrate 10. The supplied sublimation film-forming composition is preferably a liquid, more preferably a solution, at an environment of 20–30°C. Alternatively, it may be supplied in a manner that fills part or all of the recesses 24 of the uneven structure 20 (sometimes described as "a process of supplying a sublimation film-forming composition" or simply as "a filling process" or "a supply process"). The supply may also be carried out at, for example, an environment of 20–30°C.

[0158] The method of supplying the sublimation film forming composition can use well-known means, but can also use, for example, a single-wafer method represented by a rotary method; or a batch method in which multiple wafers are immersed in a composition tank, the cleaning solution supporting the uneven pattern on the wafer is replaced, and the composition is filled. The rotary method is characterized by supplying the composition to the vicinity of the rotation center while holding the wafers almost horizontally and rotating them to replace the cleaning solution supporting the uneven pattern on the wafer, and filling the composition.

[0159] After the cleaning process, the cleaning solution remains on the surface of the substrate 10. By selecting a type of cleaning solution that is soluble in the sublimable film-forming composition, it becomes easier to replace the remaining cleaning solution with the sublimable film-forming composition. Therefore, as a cleaning solution, at least one alcohol selected from methanol, 1-propanol, and 2-propanol, which have 3 or fewer carbon atoms, is generally preferred.

[0160] Furthermore, the sublimable substance used in the sublimable film-forming composition can be purified beforehand. Purification of the sublimable substance can be achieved using separation methods such as sublimation purification or distillation.

[0161] After the filling process, such as Figure 1As shown in (b), the sublimable substance in the sublimable film forming composition 30 is solidified, and a sublimable film 50 containing the solidified sublimable substance is formed on the uneven structure 20 (sometimes described as "the process of forming a sublimable film" or simply "the solidification process"). The sublimable film 50 filling the recesses 24 of the uneven structure 20 can suppress the pattern collapse of the uneven structure 20.

[0162] In the solidification process, the sublimable substances of the solid can be precipitated by cooling, or by heating and using appropriate environmental conditions to evaporate the solvent and precipitate the sublimable substances of the solid through its heat of vaporization.

[0163] In this embodiment, by appropriately selecting solvents A1, A2, B1, and B2 used in the sublimation film-forming composition as described above, solvent evaporation (drying) can also be carried out, for example, at room temperature and pressure (20°C to 25°C, 1 atm).

[0164] Furthermore, by setting the lower limit of the freezing point of the sublimable substance to be above the aforementioned lower limit value, the sublimable substance can be solidified by the heat of vaporization of the solvent without extreme cooling.

[0165] In addition, when the solidification process is carried out at normal temperature and pressure, an inactive gas may be blown onto the substrate 10 to promote the evaporation of the solvent, for example, by rotating the substrate 10.

[0166] After the solidification process, such as Figure 1 As shown in (c), a solid sublimable substance is sublimated to remove the sublimable film 50 on the uneven structure 20 (sometimes described as "step of removing sublimable film" or simply "removal step").

[0167] The method for sublimating a substance can be appropriately selected based on its boiling point. For example, if the boiling point is low, it can be sublimated at room temperature and pressure, but if necessary, heating or pressure reduction can also be used.

[0168] Figure 2-7 The manufacturing method shown is based on wafer patterns, but the present invention is not limited thereto. The substrate manufacturing method of this embodiment can also be based on resist patterns, and the collapse of the resist pattern can be suppressed by using the sublimation film forming composition of the present invention in its cleaning and drying processes.

[0169] Regarding the aforementioned supply process, a manufacturing method has been described that is performed after the cleaning process, but it is not limited to this and can also be performed after various treatments applied to the uneven structure 20. For example, the supply process can also be performed after the chemical solution for forming a water-repellent protective film has been applied to the uneven structure 20.

[0170] The substrate manufacturing method can also combine one or more well-known processes in addition to the above-described steps. For example, surface treatments such as plasma treatment can be performed after the above-described removal process.

[0171] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations may be employed. Furthermore, the present invention is not limited to the described embodiments; modifications and alterations that achieve the objectives of the present invention are all included within the scope of the present invention.

[0172] Furthermore, in this specification, the ordinal numbers such as "1st", "2nd", and "3rd", and the symbols such as "A" and "B", unless otherwise specified, are added only to distinguish components with the same name, and do not refer to specific characteristics of the components (such as order or importance).

[0173] Example

[0174] The present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to the description of these embodiments.

[0175] <Preparation of Sublimation Film-Forming Compositions>

[0176] (Examples 1-31, Comparative Example 1)

[0177] A sublimable film-forming composition was prepared by mixing and dissolving a sublimant (sublimable substance) in a solvent at approximately 25°C to achieve the sublimant concentration (mass %) described in Table 1. The boiling point (°C) of the sublimant, the boiling point (°C) of the solvent, and the saturated solubility (mass %) of the sublimant in the solvent are shown in Table 1.

[0178] Saturated solubility refers to the saturated concentration of a sublimant dissolved in a solvent, as measured below.

[0179] First, prepare a mixture of sublimation agent and solvent at a mass ratio of approximately 3:1, heat it to 40°C, and then cool it to room temperature (approximately 25°C). If the mixture exists as a solid-liquid mixture at room temperature, take 10 μL of the liquid portion using a microsyringe, dilute it 100 times (volume ratio) with dilution solvent, and analyze it using gas chromatography to obtain the saturated solubility (mass %). If no sublimation occurs and the solution is homogeneous at room temperature, increase the amount of sublimation agent relative to solvent and repeat the same procedure. Furthermore, if the liquid portion is too small to be taken with a microsyringe at room temperature, increase the amount of solvent relative to sublimation agent and repeat the same procedure. The mass ratio calculated according to gas chromatography is as follows: The area ratio detected by an FID detector using a Shimadzu Corporation GC-2010 gas chromatograph fitted with a capillary column (model TC-1, GL Sciences Inc., 30m long, 5μm liquid phase thickness, 0.32mm inner diameter) is converted to a mass ratio based on the area ratio of the diluent prepared by dissolving 1% by mass of the sublimant in each solution of the solvent. The diluent used in gas chromatography must be selected to obtain peaks of the sublimant and solvent sufficiently far from the analyte in the gas chromatography, specifically one with an development time distance of 0.1 minutes or more on the chromatogram.

[0180] (Examples 32-64, Comparative Examples 2 and 3)

[0181] A sublimation film-forming composition was prepared by mixing and dissolving at least one of solvents 1 to 3 at approximately 25°C in the mixing ratios (mass %) shown in Table 2. The boiling points (°C) of the sublimation agent and the solvents are shown in Table 2, and the saturated solubility (mass %) of the sublimation agent in the solvents is shown in Table 4.

[0182] (Examples 65-75)

[0183] A sublimable film-forming composition was prepared by mixing sublimant 1 and / or sublimant 2 (sublimable substances) with solvent 1 and solvent 2 at approximately 25°C and dissolving them in the mixing ratios (mass %) shown in Table 3. The boiling points (°C) of the sublimant and the solvents are shown in Table 3, and the saturated solubility (mass %) of the sublimant in the solvents is shown in Table 4.

[0184] Furthermore, the heat of solidification and freezing point of the sublimation agents recorded in Tables 1-4 are revealed in Table 5.

[0185] <Substrate Manufacturing>

[0186] First, a silicon substrate with a raised and recessed structure formed on its surface is cut into 1cm × 1.5cm sizes to prepare an evaluation substrate. The raised and recessed structure has multiple generally cylindrical protrusions with an aspect ratio of 22 and a pattern width of 19nm in cross-sectional view, with a spacing of 90nm (the total distance of the width of the protrusion and the adjacent spacing of the protrusions).

[0187] Subsequently, the surface of the uneven structure of the evaluation substrate was dry-cleaned by UV / O3 irradiation.

[0188] Subsequently, the evaluation substrate is placed in a spin coater, and 2-propanol is supplied to create a state in which the recesses in the uneven structure are supported by liquid (2-propanol).

[0189] Subsequently, the sublimable film-forming composition obtained above in a solution state is dropped onto the surface of the uneven structure, replacing the residual liquid of 2-propanol with the sublimable film-forming composition (step (I)).

[0190] Subsequently, the evaluation substrate is rotated at 100 revolutions per minute using a spin coater to visually confirm the formation of the sublimation film (the solidified film of the sublimation substance) (step (II)).

[0191] Then, continue to rotate it until the disappearance of the sublimation film is visually confirmed (step (III)).

[0192] In addition, the above processes (I) to (III) are carried out in a nitrogen atmosphere at 23 to 24°C and 1 atmosphere.

[0193] Subsequently, the evaluation substrate obtained after process (III) was observed using a scanning electron microscope (SEM) (SU8010, manufactured by Hitachi High-Technologies Corporation) to evaluate the proportion of protrusion collapse (pattern collapse) in the uneven structure (pattern collapse rate).

[0194] For the "pattern collapse rate," SEM was used to capture electron microscope images (secondary electron images) of the central portion of the evaluation substrate at a magnification of approximately 500 to 600 protrusions entering the field of view. The number of collapsed protrusions in the acquired images was calculated, and the percentage of each collapsed protrusion in the field of view was determined. The values ​​were rounded to the nearest 10 according to JIS Z 8401.

[0195] Furthermore, the SEM images obtained in Examples 1, 3, 5, 21, 22, and Comparative Example 1 are respectively revealed in... ​In Comparative Example 1 and Example 1, planar collapse occurred; in Example 3 and Example 5, no planar collapse occurred but some degree of strip collapse occurred; and in Example 21 and Example 22, strip collapse also occurred in small amounts.

[0196] In addition, in Table 3, the boiling point of isoboronol is defined as its sublimation point. In the table, 1233Z is the abbreviation for cis-1-chloro-3,3,3-trifluoropropene, and N71 is the abbreviation for Novec (registered trademark) 7100.

[0197] [Table 1]

[0198]

[0199] [Table 2]

[0200]

[0201] [Table 3]

[0202]

[0203] [Table 4]

[0204] Table 4

[0205]

[0206] [Table 5]

[0207] Table 5

[0208]

[0209] Compared to Comparative Example 1, the sublimation film-forming compositions of Examples 1-31 exhibited suppressed pattern collapse rates; compared to Comparative Examples 2-3, the sublimation film-forming compositions of Examples 32-75 exhibited suppressed pattern collapse rates. In these examples, it was observed that the occurrence of stripe collapse was suppressed.

[0210] The sublimation film-forming compositions of Examples 1-75 are suitable for use in the manufacturing process of substrates with uneven structures, and can improve the manufacturing stability of the substrates.

[0211] This application claims priority based on Japanese Patent Application No. 2020-046815, filed on March 17, 2020, all of which are incorporated herein by reference.

[0212] Explanation of reference numerals in the attached figures

[0213] 10 substrate

[0214] 20. Concave-convex structure

[0215] 22 convex part

[0216] 24 recess

[0217] 30 Sublimation Film-Forming Compositions

[0218] 50 Sublimable membrane

Claims

1. A sublimable film-forming composition comprising a sublimable substance, wherein the sublimable film-forming composition comprises: Solvent A2, wherein the saturated solubility of the sublimable substance is greater than 10% by mass; and Solvent B2, wherein its content in the sublimable film-forming composition is greater than that of solvent A2, and its boiling point is lower than the boiling point of the sublimable substance at 1 atmosphere and lower than the boiling point of solvent A2, The sublimable substance is at least one selected from the group consisting of norbornene, norbornane, camphor, pyrazine, 2,3-dichloropyrazine, 2,6-dichloropyrazine, 2,6-dichloropyridine, tetrahydrodicyclopentadiene, dimethyl oxalate, isobornol, neopentyl alcohol, neopentyl glycol, and ethylene carbonate. The solvent A2 is at least one selected from the group consisting of tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-butanol, acetone, methyl acetate, ethyl acetate, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, and trans-1-chloro-3,3,3-trifluoropropene. Solvent B2 is selected from at least one of the following groups: pentane, 3-methylpentane, hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, trans-1-chloro-3,3,3-trifluoropropene, toluene, benzene, xylene, diethyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, methyl acetate, and ethyl acetate. The content of the sublimable substance in the sublimable film-forming composition is more than 0.1% by mass and less than 40% by mass. The content of solvent A2 in the sublimable film-forming composition is 0.1% by mass or more and 30% by mass or less. The content of solvent B2 in the sublimable film-forming composition is more than 50% by mass and less than 99.8% by mass.

2. The sublimation film-forming composition according to claim 1, wherein, The difference between the boiling point of solvent A2 and the boiling point of solvent B2 is greater than 5°C.

3. A sublimation film-forming composition comprising: Sublimation substances; and Solvent A1, wherein the saturated solubility of the sublimable substance is greater than 10% by mass. The boiling point of solvent A1 is more than 5°C lower than the boiling point of the sublimable substance at 1 atmosphere. The sublimable substance is at least one selected from the group consisting of norbornene, norbornane, pyrazine, 2,3-dichloropyrazine, 2,6-dichloropyrazine, 2,6-dichloropyridine, tetrahydrodicyclopentadiene, dimethyl oxalate, isobornol, neopentyl alcohol, neopentyl glycol, and ethylene carbonate. The solvent A1 is at least one selected from the group consisting of tetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-butanol, acetone, methyl acetate, ethyl acetate, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichloroethylene, cis-1-chloro-3,3,3-trifluoropropene, and trans-1-chloro-3,3,3-trifluoropropene. The content of the sublimable substance in the sublimable film-forming composition is more than 0.1% by mass and less than 80% by mass. The content of solvent A1 in the sublimable film-forming composition is more than 0.5% by mass and less than 99.9% by mass.

4. The sublimation film-forming composition according to claim 3, comprising: Solvent B1 has a boiling point lower than that of solvent A1.

5. The sublimation film-forming composition according to claim 3 or 4, wherein, The content of solvent A1 in the sublimation film-forming composition is 50% by mass or more.

6. The sublimation film-forming composition according to claim 1 or 3, wherein, The heat of solidification of the sublimable substance is below 200 J / g.

7. The sublimation film-forming composition according to claim 1 or 3, wherein, The sublimable substance has a freezing point of 5°C or higher at 1 atmosphere.

8. The sublimation film-forming composition according to claim 1 or 3, wherein, The sublimable substance has a boiling point below 300°C at 1 atmosphere.

9. The sublimation film-forming composition according to claim 1 or 3, used to suppress pattern collapse of an uneven structure formed on a substrate.

10. The sublimation film forming composition according to claim 9, used to process a substrate having a patterned structure of less than 30 nm.

11. The sublimation film forming composition according to claim 10, used to process the substrate having a textured structure with a pattern size of less than 20 nm.

12. A method for manufacturing a substrate, comprising: The process of preparing a substrate with an uneven surface; The process of supplying the surface with a sublimable film forming composition comprising a sublimable substance; The process of solidifying the sublimation film forming composition to form a sublimation film on the surface; as well as The process of sublimating the sublimable substance to remove the sublimable film. The sublimation film-forming composition comprising the sublimation substance is the sublimation film-forming composition according to any one of claims 1 to 8.

13. The method for manufacturing a substrate according to claim 12, wherein, The surface of the substrate has a patterned uneven structure with a pattern size of less than 30 nm.

14. The method for manufacturing a substrate according to claim 13, wherein, The surface of the substrate has the uneven structure with a pattern size of less than 20 nm.

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