阅读说明：本技术 凹凸图案干燥用组合物、及表面具有凹凸图案的基板的制造方法 (Composition for drying uneven pattern, and method for producing substrate having uneven pattern on surface ) 是由 照井贵阳 公文创一 福井由季 于 2020-03-17 设计创作，主要内容包括：本发明的凹凸图案干燥用组合物包含升华性物质、及1大气压下的沸点比升华性物质的沸点或升华点低5℃以上且1大气压下的沸点为75℃以下的溶剂。(The composition for drying an uneven pattern of the present invention comprises a sublimable substance and a solvent having a boiling point at 1atm which is lower by 5 ℃ or more than the boiling point or sublimation point of the sublimable substance and a boiling point at 1atm which is 75 ℃ or less.)

1. A composition for drying a concave-convex pattern, comprising:

sublimable substance, and

a solvent having a boiling point at 1 atmosphere which is lower by 5 ℃ or more than the boiling point or sublimation point of the sublimable substance and a boiling point at 1 atmosphere of 75 ℃ or less.

2. The composition for drying a concave-convex pattern according to claim 1, wherein the freezing point of the sublimable substance is 5 ℃ or higher under 1 atmosphere.

3. The composition for drying an uneven pattern according to claim 1 or 2, wherein a boiling point or a sublimation point of the sublimable substance is 300 ℃ or lower.

4. The composition for drying an uneven pattern according to any one of claims 1 to 3, wherein the sublimable substance includes one or more selected from the group consisting of a fluoroalkane having 3 to 6 carbon atoms, a fluorocycloalkane having 3 to 6 carbon atoms, a compound in which a hydrogen atom of the fluoroalkane is substituted with a chlorine atom, and a compound in which a hydrogen atom of the fluorocycloalkane is substituted with a chlorine atom.

5. The uneven pattern drying composition according to any one of claims 1 to 3, wherein the sublimable substance includes one or more selected from the group consisting of naphthalene, 1,2,2,3,3, 4-heptafluorocyclopentane, 1-dichlorooctafluorocyclopentane, 1,2,2,3,3,4, 4-octafluorocyclohexane, perfluorocyclohexane, camphor, dimethyl oxalate, neopentyl alcohol, tetrahydrodicyclopentadiene, and pyrazine.

6. The composition for drying an uneven pattern according to claim 5, wherein the sublimable substance contains 1,1,2,2,3,3, 4-heptafluorocyclopentane.

7. The uneven pattern drying composition according to any one of claims 1 to 6, wherein a content of the sublimable substance is 1 mass% or more and 80 mass% or less with respect to a total mass of the uneven pattern drying composition.

8. The composition for drying an uneven pattern according to any one of claims 1 to 7, wherein the solvent includes one or more selected from the group consisting of hydrocarbons optionally having at least one of a fluorine atom and a chlorine atom, ethers optionally having at least one of a fluorine atom and a chlorine atom, alcohols optionally having at least one of a fluorine atom and a chlorine atom, and esters.

9. The composition for drying an uneven pattern according to claim 8, wherein the solvent contains one or more selected from the group consisting of hexane, trans-1-chloro-3, 3, 3-trifluoropropene, cis-1-chloro-3, 3, 3-trifluoropropene, diethyl ether, tetrahydrofuran, 1,1,1,3,3, 3-hexafluoro-2-methoxypropane, 1,1,1,2,2,3,3,4, 4-nonafluorobutyl methyl ether, 3-methylpentane, cyclopentane, and methyl acetate.

10. The composition for drying an uneven pattern according to any one of claims 1 to 9, which is used for treating a substrate having an uneven pattern with a pattern size of 30nm or less.

11. The composition for drying an uneven pattern according to claim 10, used for treating the substrate having an uneven pattern in which the pattern size is 20nm or less.

12. A method for manufacturing a substrate having a concave-convex pattern on a surface thereof, comprising:

a step (I) for supplying a composition for drying, which contains a sublimable substance and a solvent having a boiling point at 1atm that is 5 ℃ or more lower than the boiling point or sublimation point of the sublimable substance and a boiling point at 1atm that is 75 ℃ or less, to the recessed portions of the uneven pattern in a solution state;

a step (II) of drying the solvent in the recess to solidify the sublimable substance; and

and (III) sublimating the sublimable substance.

13. The method of manufacturing a substrate having a surface with a concave-convex pattern according to claim 12, wherein a step of purifying the sublimable substance is provided before the step (I).

14. The method of manufacturing a substrate having a concave-convex pattern on a surface according to claim 12 or 13, wherein the substrate has the concave-convex pattern having a pattern size of 30nm or less on the surface.

15. The method of manufacturing a substrate having a concave-convex pattern on a surface according to claim 14, wherein the substrate has the concave-convex pattern having the pattern size of 20nm or less on the surface.

Technical Field

The present invention relates to a composition for drying an uneven pattern and a method for producing a substrate having an uneven pattern on a surface thereof.

Background

In the manufacture of semiconductor chips, a fine uneven pattern is formed on the surface of a substrate (wafer) by film formation, photolithography, etching, or the like, and then wet treatment such as a cleaning step using water or an organic solvent is performed to clean the surface of the wafer, and a drying step is also performed to remove a liquid such as a cleaning liquid or a rinse liquid attached to the wafer by the wet treatment. It is known that, in the drying step, the semiconductor substrate having the fine uneven pattern is likely to be deformed or collapsed. This is considered to be caused by stress due to surface tension generated between the liquid adhering to the concave-convex pattern and the semiconductor interface. Various methods have been proposed to suppress the stress and prevent the fine uneven pattern from being deformed or collapsed.

Patent document 1 describes a method of supplying a treatment liquid containing a sublimable substance in a molten state to a pattern formation surface of a substrate, solidifying the treatment liquid on the pattern formation surface to obtain a solidified body, and then sublimating the solidified body.

Patent documents 2 and 3 describe a method of filling concave portions of an uneven pattern with a solution in which a sublimable substance is dissolved in a solvent, drying the solvent in the solution, depositing a solid sublimable substance in the concave portions, and then sublimating the sublimable substance.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2018-22861

Patent document 2: japanese patent laid-open No. 2013-42093

Patent document 3: japanese patent laid-open No. 2012-243869

Disclosure of Invention

Problems to be solved by the invention

As described in patent documents 1 to 3, in order to dry a substrate having an uneven pattern formed thereon using a sublimable substance, a step of replacing a liquid remaining in the uneven pattern (hereinafter, also simply referred to as "residual liquid") with a treatment liquid containing the sublimable substance is generally performed.

However, in patent document 1, there is a case where a melt in which a fluorinated carbon compound that is a sublimable substance is melted is used, and the fluorinated carbon compound may be solidified at the tip end portion of the supply nozzle, and for example, when the melt in which the solidified substance is mixed is supplied to the substrate surface, there is a concern that the uneven pattern may be adversely affected.

In patent documents 2 and 3, since a solution in which a sublimable substance is dissolved in a solvent is used, the problem of solidification at the tip of the supply nozzle as in patent document 1 is less likely to occur.

However, in recent years, with the miniaturization of the uneven pattern of the semiconductor wafer, the aspect ratio (height/width) of the uneven pattern has been increasing, and pattern collapse during drying of the residual liquid is more likely to occur.

According to the studies of the present inventors, it has been found that, in a concave-convex pattern having a high aspect ratio, even when a solution in which a sublimable substance is dissolved in a solvent is used, pattern collapse cannot be sufficiently suppressed by the combination of the sublimable substance and the solvent.

Further, after the solution is supplied to the concave portions of the uneven pattern, the solvent in the solution is dried to solidify the sublimable substance, but it has been found that a long time is required for the sublimable substance to solidify depending on the boiling point of the solvent.

The present invention addresses the problem of providing an uneven pattern drying composition that is less likely to cause solidification at the tip of a supply nozzle, and that can reduce the time required for the sublimable substance to solidify after being supplied to the uneven pattern surface, and that can suppress pattern collapse when drying the uneven pattern surface, particularly for uneven patterns having a high aspect ratio, and a method for producing a substrate having an uneven pattern on the surface using the drying composition.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that the above problems can be solved by the following configuration, and have completed the present invention. Namely, the present invention is as follows.

According to the present invention, there is provided,

provided is a composition for drying a concave-convex pattern, which comprises:

sublimable substance, and

a solvent having a boiling point at 1 atmosphere which is lower by 5 ℃ or more than the boiling point or sublimation point of the sublimable substance and a boiling point at 1 atmosphere of 75 ℃ or less.

In addition, according to the present invention,

provided is a method for manufacturing a substrate having a concave-convex pattern on a surface thereof, the method including:

a step (I) for supplying a composition for drying, which contains a sublimable substance and a solvent having a boiling point at 1atm lower by 5 ℃ or more than the boiling point or sublimation point of the sublimable substance and a boiling point at 1atm of 75 ℃ or less, to the recessed portions of the uneven pattern in a solution state;

a step (II) of drying the solvent in the recess to solidify the sublimable substance; and

and (III) sublimating the sublimable substance.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide an uneven pattern drying composition which is less likely to cause solidification at the tip of a supply nozzle, and which can reduce the time required for the sublimable substance to solidify after being supplied to the surface of the uneven pattern, and which can suppress pattern collapse when drying the surface of the uneven pattern, particularly for uneven patterns having a high aspect ratio, and a method for producing a substrate having an uneven pattern on the surface thereof using the drying composition.

Drawings

Fig. 1 is a process cross-sectional view of an example of a substrate manufacturing process.

Detailed Description

The present invention will be described in detail below.

[ composition for drying irregular Pattern ]

The composition for drying an uneven pattern (also simply referred to as "drying composition") of the present invention contains a sublimable substance and a solvent having a boiling point at 1atm that is 5 ℃ or more lower than the boiling point or sublimation point of the sublimable substance and a boiling point at 1atm that is 75 ℃ or less.

< subliming substance >

The sublimable substance contained in the drying composition of the present invention will be described.

The sublimable substance in the present specification means a substance having a vapor pressure in a solid state.

The sublimable substance in the present invention can be used as long as it is a solid substance having a vapor pressure at a specific temperature in principle, but is not preferable because it may complicate the apparatus or adversely affect the substrate (semiconductor) to be processed in the case where an extremely low temperature is required for solidification or an extremely high temperature is required for sublimation. In particular, there is a concern that moisture in the environment may interfere with uniform solidification of the sublimable substance when the moisture is solidified and mixed in the step (II) described later, or that the effect of suppressing pattern collapse may be impaired. Therefore, the freezing point of the sublimable substance is preferably 5 ℃ or higher, more preferably 20 ℃ or higher, under 1 atmosphere.

The sublimable substance is preferably removed from the volatile substance by a separation method such as sublimation purification or distillation in advance to reduce the residue after sublimation drying. From the viewpoint of easy purification as described above, the boiling point or sublimation point of the sublimable substance is preferably 300 ℃ or lower. Further, the boiling point or sublimation point of the sublimable substance is more preferably 120 ℃ or lower, because the step (III) (sublimation of the sublimable substance) described later is easily performed in the process at normal temperature and pressure.

The boiling point or sublimation point of the sublimable substance containing a plurality of components is the boiling point or sublimation point of the component having the highest content (mass%) among the components contained in the sublimable substance (however, when 2 or more components having the highest content are present, the boiling point or sublimation point having the highest temperature is used).

The boiling point of the sublimable substance is defined as the initial boiling point in JIS K2254 (ISO 3405).

Note that, in the case where the sublimation point is used depending on the substance, the sublimation point is used.

The freezing point of the sublimable substance was determined by DSC under the condition of-10 ℃/min. The freezing point of the sublimable substance containing a plurality of components is the freezing point of the component having the highest content (mass%) in the components contained in the sublimable substance (however, when there are 2 or more components having the highest content, the freezing point of the component having the highest content is the freezing point of the component having the highest content).

When the sublimable substance is a solid and a temperature region having a vapor pressure (hereinafter, also referred to as a "sublimation temperature region") is present at 10 ℃ or higher, even if the drying composition in a solution state is supplied in an environment of a general room temperature of 20 to 25 ℃ in a clean room, the sublimable substance can be solidified only by cooling by the heat of vaporization of the solvent in the drying composition, and therefore, it is more preferable.

Further, if the sublimation temperature range is in the range of 20 to 25 ℃, the sublimable substance can be sublimated and removed without promoting sublimation by heating, pressure reduction, or the like, and therefore, it is preferable.

The vapor pressure in defining the sublimation temperature region is preferably 10Pa or more, and more preferably 50Pa or more.

The type of the sublimable substance is not limited as long as it does not adversely affect the substrate (preferably, semiconductor) material, and examples thereof include a fluorine-containing compound, naphthalene, p-dichlorobenzene, camphor (camphor), dimethyl oxalate, neopentyl alcohol, tetrahydrodicyclopentadiene, pyrazine, carbonate of alkylamine, and the like, preferably a fluorine-containing compound, camphor, dimethyl oxalate, neopentyl alcohol, tetrahydrodicyclopentadiene, pyrazine, or naphthalene, and more preferably a fluorine-containing compound. These can be used alone, also can be combined with 2 more than use.

Examples of the fluorine-containing compound include fluoroalkanes having 1 or more fluorine atoms and having 3 to 6 carbon atoms, fluorocycloalkanes having 1 or more fluorine atoms and having 10 carbon atoms, tetrafluorotetracyanoquinodimethane, hexafluorocyclotriphosphazene, and compounds in which a hydrogen atom of the fluoroalkane is substituted with a substituent, compounds in which a hydrogen atom of the fluorocycloalkane is substituted with a substituent, and compounds in which a hydrogen atom of the fluorocycloalkane is substituted with a substituent. Examples of the substituent include a halogen atom (preferably chlorine atom, bromine atom, iodine atom) other than fluorine atom, a hydroxyl group, a carboxyl group, an oxo group, an alkyl group, an alkoxy group, and a group obtained by combining these groups.

The fluorine-containing compound is particularly preferably at least 1 compound selected from the group consisting of a fluoroalkane having 3 to 6 carbon atoms, a fluorocycloalkane having 3 to 6 carbon atoms, a compound in which a hydrogen atom of the fluoroalkane is substituted with a chlorine atom, and a compound in which a hydrogen atom of the fluorocycloalkane is substituted with a chlorine atom.

Examples of the sublimable substance having a sublimation temperature range of 20 to 25 ℃ include naphthalene, 1,2,2,3,3, 4-heptafluorocyclopentane (hereinafter, may be referred to as HFCPA), 1-dichlorooctafluorocyclopentane (hereinafter, may be referred to as DCOFCPA), perfluorocyclohexane (hereinafter, may be referred to as PFCHA), 1,2,2,3,3,4, 4-octafluorocyclohexane, camphor, dimethyl oxalate, neopentyl alcohol, tetrahydrodicyclopentadiene, pyrazine and the like. These can be used alone, also can be combined with 2 more than use.

As the sublimable substance, 1,2,2,3,3, 4-Heptafluorocyclopentane (HFCPA) is particularly preferable. HFCPA is generally available, and commercially available products such as "Zeorora H" manufactured by Zeon Corporation may also be used.

The content of the sublimable substance contained in the drying composition of the present invention is not particularly limited, and is preferably 1 to 80% by mass based on the total mass of the drying composition.

When the content of the sublimable substance is 1% by mass or more, the sublimable substance tends to be easily uniformly solidified on the substrate, and it is preferable.

On the other hand, when the content of the sublimable substance is 80% by mass or less, the cooling effect of the vaporization heat of the solvent tends to be easily obtained, and the solidification of the sublimable substance tends to be easily promoted, which is preferable. Further, the time required for sublimation (sublimation time) is preferably short because it is easy to keep the time.

The lower limit of the content of the sublimable substance is more preferably 5% by mass or more, and particularly preferably 7% by mass or more, based on the total mass of the drying composition. The upper limit of the content of the sublimable substance is more preferably 55 mass% or less, particularly preferably 53 mass% or less, based on the total mass of the drying composition.

The sublimable substance contained in the drying composition of the present invention has a boiling point or sublimation point higher than that of the solvent by 5 ℃ or more at 1 atmosphere. In this regard, the following description of the solvent will be described in detail.

< solvent >

The solvent contained in the drying composition of the present invention will be described.

The drying composition of the present invention is a solution obtained by dissolving the sublimable substance in a solvent.

The solvent used in the present invention includes 1 or 2 or more species satisfying the following condition (1) and the following condition (2).

Condition (1): the boiling point is lower than the boiling point or sublimation point of the sublimable substance by 5 ℃ or more under 1 atmosphere.

Condition (2): the boiling point is 75 ℃ or lower under 1 atmosphere.

In the present specification, as the boiling point of each solvent in the case of including a plurality of solvents, an azeotropic point is employed in the case of an azeotropic solvent. When the solvent is not an azeotropic solvent, a predetermined boiling point is used for each solvent.

In the present invention, in the step (II) described below, the sublimable substance is condensed by the concentration of the sublimable substance accompanied by the drying of the solvent (volatilization of the solvent), and therefore the above-mentioned condition (1) must be satisfied.

In the present invention, the boiling point under the condition (2) is preferably lower than the boiling point or sublimation point of the sublimable substance by 25 ℃ or more under 1 atmosphere.

In the present invention, a solvent satisfying the above condition (2) is used particularly from the viewpoint of reducing the time required for solidification in the step (II) described later. That is, when a solvent having a boiling point of 75 ℃ or less at 1 atmosphere pressure satisfying the above condition (2) is used, the time required for solidification in the step (II) to be described later can be reduced.

In addition, as the effects obtained by using the solvent, the following effects can be mentioned in addition to the above.

By using the solvent, the sublimable substance in the drying composition is diluted, and the amount of the sublimable substance used can be reduced. Thus, even when an expensive sublimable substance such as a fluorine-containing compound is used, the sublimable substance is used in a smaller amount than when a melt of the sublimable substance is used, and therefore, the sublimable substance is excellent in terms of economy.

By using the solvent, the drying composition can be supplied as a solution in which the sublimable substance is dissolved in the solvent, and therefore, the nozzle tip portion is less likely to be solidified, and damage to the uneven pattern to which the drying composition is applied can be avoided.

By including the solvent in the drying composition, the compatibility with the liquid (residual liquid) remaining in the uneven pattern can be improved as compared with the case where the solvent is not included (that is, the case where the melt of the sublimable substance is used). This enables the residual liquid on the substrate surface to be replaced with the drying composition more efficiently.

By drying (volatilizing) the solvent, the heat of vaporization at this time can be used to promote solidification of the sublimable substance in the drying composition. In this case, the film thickness of the film (solid sublimable substance film) formed by solidifying the sublimable substance can be made thinner than the film (solid sublimable substance film) formed by applying the melt composed of only the sublimable substance.

The solvent contained in the drying composition of the present invention is not particularly limited as long as it satisfies the above condition (1) and the above condition (2), but is preferably a solvent that is compatible with water, an alcohol having 3 or less carbon atoms (for example, methanol, 1-propanol, 2-propanol, or the like), or a mixture thereof, which is a general solvent used in the semiconductor cleaning step, because the replacement of the drying composition of the present invention with the liquid (residual liquid) held in at least the concave portion of the substrate in the step (I) described later can be efficiently performed.

The term "having compatibility" means that the amount of the "solvent used in the cleaning step" which can be dissolved in 1 part by mass of the "solvent contained in the drying composition" of the present invention is 0.05 parts by mass or more at 25 ℃ under 1 atmosphere.

The type of the solvent contained in the drying composition of the present invention is not particularly limited as long as the above conditions (1) and (2) are satisfied, and examples thereof include hydrocarbons optionally having at least one of a fluorine atom and a chlorine atom, ethers optionally having at least one of a fluorine atom and a chlorine atom, alcohols optionally having at least one of a fluorine atom and a chlorine atom, and esters. These can be used alone, also can be combined with 2 more than use.

As the solvent, hydrocarbons optionally having at least one of a fluorine atom and a chlorine atom, or ethers optionally having at least one of a fluorine atom and a chlorine atom are preferable.

Examples of the hydrocarbon optionally having a fluorine atom include an alkane or cycloalkane having 4 to 10 carbon atoms, an alkene or cycloalkene having 4 to 10 carbon atoms, and an aromatic hydrocarbon having 6 to 10 carbon atoms, and specifically, hexane (boiling point 69 ℃, vapor pressure 16kPa), pentane (boiling point 36 ℃, vapor pressure 53kPa), 2-methylpentane (boiling point 60 ℃, vapor pressure 23kPa), cyclopentane (boiling point 49 ℃, vapor pressure 45kPa), 3-methylpentane (boiling point 63 ℃, vapor pressure 20kPa), and the like.

Examples of the hydrocarbon include alkanes having 4 to 10 carbon atoms and having fluorine atoms, alkenes having 4 to 10 carbon atoms, and aromatic hydrocarbons having 6 to 10 carbon atoms, and specifically, perfluorohexane (boiling point 60 ℃, vapor pressure 27kPa at 25 ℃) and the like are mentioned.

Examples of the hydrocarbon include alkanes having 1 to 10 carbon atoms and having chlorine atoms, alkenes having 2 to 10 carbon atoms, and hydrocarbons having 6 to 10 carbon atoms and optionally having fluorine atoms among aromatic hydrocarbons, and specific examples thereof include dichloromethane (boiling point 40 ℃, vapor pressure 47kPa), trichloromethane (boiling point 62 ℃, vapor pressure 21kPa), trichlorofluoromethane (boiling point 24 ℃, vapor pressure 84kPa), trans-1-chloro-3, 3, 3-trifluoropropene (boiling point 18 ℃, vapor pressure 133kPa), cis-1-chloro-3, 3, 3-trifluoropropene (boiling point 39 ℃, vapor pressure 49 kPa).

The boiling point is a value of 1atm, and the vapor pressure is a value of 20 ℃ unless otherwise stated. The same applies to the following.

Examples of the ethers optionally having a fluorine atom include ethers optionally having a fluorine atom having 4 to 10 carbon atoms, and specific examples thereof include diethyl ether (boiling point 35 ℃, vapor pressure 59kPa), diisopropyl ether (boiling point 69 ℃, vapor pressure 21kPa), tert-butyl methyl ether (boiling point 55 ℃, vapor pressure 27kPa), tetrahydrofuran (boiling point 65 ℃, vapor pressure 19kPa), 1,1,1,3,3, 3-hexafluoro-2-methoxypropane (boiling point 61 ℃, vapor pressure 27kPa), 1,1,1,2,2,3,3,4, 4-nonafluorobutyl methyl ether (boiling point 61 ℃, vapor pressure 28kPa at 25 ℃), and the like.

Examples of the alcohols optionally having a fluorine atom include trifluoroethanol (boiling point: 74 ℃, vapor pressure: 10kPa at 25 ℃) and the like.

Examples of the esters include methyl acetate (boiling point: 57 ℃ C., vapor pressure: 23kPa) and ethyl acetate (boiling point: 77 ℃ C., vapor pressure: 10 kPa).

Among the above solvents, hexane, trans-1-chloro-3, 3, 3-trifluoropropene, cis-1-chloro-3, 3, 3-trifluoropropene, diethyl ether, tetrahydrofuran, 1,1,1,3,3, 3-hexafluoro-2-methoxypropane, or 1,1,1,2,2,3,3,4, 4-nonafluorobutyl methyl ether, 3-methylpentane, cyclopentane, methyl acetate, ethyl acetate are particularly preferable from the viewpoint of ease of handling.

(other solvents)

If the composition range is not outside the composition range specified in the present invention, the drying composition may further contain "another solvent" for the purpose of adjusting wettability to the substrate and/or the uneven pattern, in addition to the sublimation material and the solvent, which are essential components. Examples thereof include water, hydrocarbons, esters, ethers, ketones, sulfoxide solvents, alcohols, polyhydric alcohol derivatives, nitrogen-containing compounds, and the like, and refer to solvents that do not belong to the solvents used as the essential components. Examples of the hydrocarbon include toluene, benzene, xylene, pentane, hexane, heptane, octane, nonane, decane, etc., examples of the ester include ethyl acetate, propyl acetate, butyl acetate, ethyl lactate, ethyl acetoacetate, etc., examples of the ether include diethyl ether, dipropyl ether, dibutyl ether, tert-butyl methyl ether, tetrahydrofuran, dioxane, etc., examples of the ketone include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, etc., examples of the sulfoxide-based solvent include dimethyl sulfoxide, etc., examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, butanol, 4-methyl-2-pentanol, ethylene glycol, 1, 3-propylene glycol, etc., examples of the derivative of the polyhydric alcohol include diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol, 1, 3-propylene glycol, etc., and examples of the derivative of the polyhydric alcohol include ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol, etc, Ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and the like, and examples of the nitrogen-containing compound include formamide, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, and the like, and among them, a solvent which does not belong to a solvent used as the essential component can be exemplified.

The content of the solvent contained in the drying composition of the present invention is not particularly limited, and is preferably 20 to 99% by mass based on the total mass of the drying composition. When the content of the solvent is 20% by mass or more, the cooling effect of the vaporization heat of the solvent is easily obtained, and the sublimable substance tends to be easily accelerated to solidify, so that it is preferable. On the other hand, when the content of the solvent is 99% by mass or less, the sublimable substance tends to be easily and uniformly solidified on the substrate, and it is preferable. The lower limit of the content of the solvent is more preferably 45% by mass or more, and particularly preferably 47% by mass or more, based on the total mass of the drying composition. The upper limit of the content of the solvent is more preferably 95% by mass or less, and particularly preferably 93% by mass or less, based on the total mass of the drying composition.

The drying composition of the present invention is preferably a liquid (solution) at-15 to 50 ℃ and more preferably a liquid (solution) at 0 to 40 ℃ from the viewpoint of easy handling (production, storage, transportation, etc.). Further, from the viewpoint of simplifying the structure of the apparatus in which the ejection mechanism is not required to be kept warm or heated, it is particularly preferable that the ejection mechanism is liquid at 20 to 30 ℃.

[ method for producing substrate having uneven pattern on surface ]

The method for manufacturing a substrate having a pattern of recesses and projections on a surface thereof (also simply referred to as "method for manufacturing a substrate") according to the present invention includes:

a step (I) for supplying a composition for drying, which contains a sublimable substance and a solvent having a boiling point at 1atm that is 5 ℃ or more lower than the boiling point or sublimation point of the sublimable substance and a boiling point at 1atm that is 75 ℃ or less, to the recessed portions of the uneven pattern in a solution state;

a step (II) of drying the solvent in the recess to solidify the sublimable substance; and

and (III) sublimating the sublimable substance.

< Process (I) >

The step (I) is a step of supplying a drying composition containing a sublimable substance and a solvent in a solution state to the recesses of the uneven pattern provided on the surface of the substrate. The drying composition is the same as the drying composition of the present invention.

The substrate is not particularly limited, and a substrate including a semiconductor is preferable.

The step (I) is preferably carried out at 20 to 30 ℃. That is, it is preferable to use a composition for drying which is in a solution state at 20 to 30 ℃.

Before the drying composition is supplied in step (I), a residual liquid such as a cleaning liquid used in a cleaning step performed before the supply of the drying composition is usually present on the surface of the substrate. Then, the drying composition supplied in the step (I) is replaced with the residual liquid. The residual liquid is not particularly limited, and is usually water or an alcohol having 3 or less carbon atoms (e.g., methanol, 1-propanol, 2-propanol, etc.), and preferably at least 1 selected from methanol, 1-propanol, and 2-propanol from the viewpoint of easiness of substitution with the drying composition.

In the step (I), as long as the drying composition of the present invention is used as a drying composition and the composition is supplied in a solution state, a specific method for supplying is not particularly limited, and a known method can be used.

The drying composition is supplied to at least a part or all of the recess.

< Process (II) >

The step (II) is a step of drying the solvent in the concave portion to solidify the sublimable substance. That is, in the step (II), the solvent in the drying composition (drying composition in which the residual liquid of the uneven pattern is replaced) supplied to at least a part or all of the recessed portions in the step (I) is dried (volatilized), and the sublimable substance in the drying composition is solidified.

In the present invention, since the solvent having a boiling point of 75 ℃ or less at 1 atmosphere is used as the solvent, the time required for the sublimable substance to solidify after being supplied to the surface of the uneven pattern can be reduced, and the drying can be performed at normal temperature and pressure (20 to 25 ℃ C., 1 atm).

Further, if the freezing point of the sublimable substance is 5 ℃ or higher under 1 atmosphere, it is not necessary to make it extremely low temperature for solidification, and for example, the solvent can be dried (volatilized), and the solidification of the sublimable substance can be promoted by the heat of vaporization at that time, and therefore, this is preferable (it is possible to carry out the operation under normal temperature and pressure environment without using a special device).

The method for performing the step (II) is not particularly limited, and a process at normal temperature and pressure is preferable, and therefore, for example, a method of rotating a substrate supplied with the drying composition; a method of blowing a gas (preferably an inert gas if it is necessary to prevent the volatile vapor from igniting) onto the substrate to which the drying composition is supplied, and discharging the gas together with the dried (volatilized) solvent.

< Process (III) >

The step (III) is a step of sublimating the sublimable substance. That is, in the step (III), the sublimable substance is sublimated to remove the solidified product of the sublimable substance (the solid film of the sublimable substance) obtained in the step (II).

If the boiling point or sublimation point of the sublimable substance is 120 ℃ or lower, the step (III) can be carried out under normal temperature and pressure environment, and therefore, it is preferable.

The temperature for carrying out the step (III) is not particularly limited, and it may be carried out at normal temperature or under a heating environment (for example, 30 to 120 ℃ C., preferably 40 to 80 ℃ C.). The step (III) performed in a heated environment is also referred to as "step (IIIb)".

The method for performing the step (III) is not particularly limited, and a process at normal temperature and pressure is preferable from the viewpoint of simplification of the apparatus configuration, and therefore, for example, a method of rotating a substrate on which a solidified material of a sublimable substance is formed; a method of blowing a gas (preferably an inert gas if ignition of the vaporized sublimable substance is to be prevented) onto the substrate on which the solidified material of the sublimable substance is formed, and discharging the gas together with the vaporized sublimable substance.

The method for producing a substrate of the present invention preferably includes a step of purifying the sublimable substance before the step (I). The purification of the sublimable substance is preferably performed by a separation method such as sublimation purification or distillation.

The method for manufacturing a substrate according to the present invention can reduce the time required for the sublimable substance to solidify after being supplied to the surface of the uneven pattern, and can manufacture a dry (no residual liquid) substrate in which collapse of the uneven pattern is suppressed.

Fig. 1 (a) to (c) are process cross-sectional views showing an example of a process for producing a substrate using the drying composition.

Fig. 1 (a) shows a step of supplying a drying composition 30 to the surface of a substrate 10 and filling the drying composition 30 into the recesses 24 in the uneven pattern 20; fig. 1 (b) shows a step of solidifying the drying composition 30 to form a sublimable film 50; fig. 1 (c) shows a step of removing the sublimation film 50 by sublimating the sublimable substance.

Hereinafter, a method for manufacturing a substrate will be described in detail.

In the preparation step of the substrate 10, the following method can be used as an example of a method for forming the uneven pattern 20 on the surface of the substrate 10.

First, a resist is applied to a wafer surface, and then the resist is exposed through a resist mask, and the exposed resist or the unexposed resist is removed to produce a resist having a desired uneven pattern. Further, by pressing the mold having a pattern against the resist, a resist having an uneven pattern can also be obtained. Then, the wafer is etched. At this time, the substrate surface corresponding to the concave portion of the resist pattern is selectively etched. Finally, after the resist is stripped, a wafer (substrate 10) having an uneven pattern 20 on the surface thereof can be obtained.

The wafer on which the uneven pattern 20 is formed and the material of the uneven pattern 20 are not particularly limited, and various wafers such as a silicon wafer, a silicon carbide wafer, a wafer containing a plurality of components including a silicon element, a sapphire wafer, various compound semiconductor wafers, and a plastic wafer can be used as the wafer. As a material of the uneven pattern 20, a silicon-based material such as silicon dioxide, silicon nitride, polysilicon, or single crystal silicon, a metal-based material such as titanium nitride, tungsten, ruthenium, tantalum nitride, or tin, a material obtained by combining these materials, a resist (photoresist) material, or the like can be used.

Fig. 1 (a) shows a cross-sectional view of an example of the uneven pattern 20. The pattern size of at least one of the width and the height in the cross-sectional structure (in the substrate thickness direction) of the pattern of the uneven pattern 20, or the pattern size of at least one of the width (length in the X-axis direction), the height (length in the Y-axis direction), and the depth (length in the Z-axis direction) in the three-dimensional structure (3-dimensional coordinates of XYZ) of the pattern of the uneven pattern 20 may be, for example, 30nm or less, 20nm or less, or 10nm or less. Even when the substrate 10 having such a fine uneven pattern 20 is used, the pattern collapse rate can be reduced by using the drying composition of the present embodiment.

Such a drying composition is suitable as a composition for treating a substrate 10 having an uneven pattern 20 with a pattern size of 30nm or less, preferably 20nm or less, for example.

The lower limit of the aspect ratio of the convex portion 22 may be, for example, 3 or more, 5 or more, or 10 or more. Pattern collapse can be suppressed even in the uneven pattern 20 having the projections 22 of a brittle structure.

On the other hand, the upper limit of the aspect ratio of the convex portion 22 is not particularly limited, and may be 100 or less.

The aspect ratio of the convex portion 22 may be represented by a value obtained by dividing the height of the convex portion 22 by the width of the convex portion 22.

After the uneven pattern 20 is formed, the surface of the substrate 10 is cleaned with a cleaning liquid such as water or an organic solvent (cleaning step).

After the cleaning step, as shown in fig. 1 (a), a drying composition that is liquid in an environment of 20 to 30 ℃ is preferably supplied to the uneven pattern 20 formed on the surface of the substrate 10. At this time, the concave portions 24 of the uneven pattern 20 may be partially or entirely filled (filling step). The supply can be carried out, for example, in an environment of 20 to 30 ℃.

A known method can be used for supplying the composition for drying, and for example, a single-wafer type can be used in which the composition is supplied near the center of rotation while the wafers are rotated while being held substantially horizontally one by one, and the cleaning liquid or the like of the uneven pattern held on the wafers is replaced with the composition, and the rotation method for filling the composition is typically used; or a batch type in which a plurality of wafers are immersed in a composition tank, and a cleaning liquid or the like held on the concave-convex pattern of the wafer is replaced to fill the composition.

The used cleaning liquid remains on the surface of the substrate 10 after the cleaning step. By selecting a type of cleaning liquid that is soluble in the drying composition, the remaining cleaning liquid can be replaced with the drying composition relatively easily. Therefore, it is generally preferable to use at least 1 kind selected from alcohols having 3 or less carbon atoms such as methanol, 1-propanol, and 2-propanol as the cleaning liquid.

The sublimable substance used in the drying composition may be purified in advance. The purification of the sublimable substance may be carried out by a separation method such as sublimation purification or distillation.

After the filling step, as shown in fig. 1 (b), the sublimable substance in the drying composition 30 is solidified, and a sublimable film 50 containing a solidified body of the sublimable substance is formed on the uneven pattern 20 (solidification step). The sublimation film 50 filled in the concave portions 24 of the uneven pattern 20 can suppress pattern collapse of the uneven pattern 20.

In the solidification step, the solid sublimable substance may be precipitated by cooling, or the solid sublimable substance may be precipitated by heating or applying an appropriate environmental condition to evaporate the solvent and thereby precipitate the solid sublimable substance by the heat of vaporization.

In the present embodiment, by appropriately selecting the solvent used in the drying composition as described above, the solvent can be volatilized (dried) at, for example, normal temperature and normal pressure (20 to 25 ℃ C., 1 atm).

Further, by setting the lower limit of the freezing point of the sublimable substance to the lower limit or more, the sublimable substance can be solidified by the heat of vaporization of the solvent without requiring extreme cooling.

When the solidification step is performed at normal temperature and normal pressure, for example, a method of rotating the substrate 10 or a method of blowing an inert gas to the substrate 10 to promote volatilization of the solvent may be employed as necessary.

After the solidification step, as shown in fig. 1 (c), the sublimable substance in a solid state is sublimated to remove the sublimable film 50 on the uneven pattern 20 (removal step).

The method of sublimating the sublimable substance may be appropriately selected depending on the boiling point of the sublimable substance, and for example, in the case of a low boiling point, the sublimable substance may be sublimed at normal temperature and pressure, but if necessary, heating or pressure reduction may be performed.

The manufacturing method shown in fig. 1 is directed to wafer patterning, but the present invention is not limited thereto. The method for producing a substrate of the present embodiment is directed to a resist pattern, and the collapse of the resist pattern can be suppressed by using the drying composition of the present invention in the cleaning and drying steps thereof.

The above-described manufacturing method in which the supply step is performed after the cleaning step has been described, but the present invention is not limited thereto, and the supply step may be performed after various kinds of processing performed on the uneven pattern 20. For example, the supply step may be performed after the treatment of the chemical liquid for forming the water repellent protective film on the uneven pattern 20.

The method of manufacturing the substrate may use one or two or more known processes in combination in addition to the above-described steps. For example, the surface treatment such as plasma treatment may be performed after the removal step.

While the embodiments of the present invention have been described above, they are merely illustrative of the present invention and various configurations other than the above can be adopted. The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within a range that can achieve the object of the present invention are included in the present invention.

Hereinafter, reference examples will be given.

＜1＞

A composition for drying a concave-convex pattern, which contains a sublimable substance and a solvent,

the boiling point of the solvent is lower than the boiling point or sublimation point of the sublimable substance by 5 ℃ or more under 1 atmosphere, and

the boiling point of the solvent is 75 ℃ or lower under 1 atmosphere.

＜2＞

The composition for drying an uneven pattern according to < 1 >, wherein the freezing point of the sublimable substance is 5 ℃ or higher under 1 atmosphere.

＜3＞

The composition for drying an uneven pattern according to < 1 > or < 2 >, wherein the sublimable substance has a boiling point or sublimation point of 300 ℃ or lower.

＜4＞

The uneven pattern drying composition according to any one of < 1 > - < 3 >, wherein the sublimable substance is at least 1 compound selected from the group consisting of a fluoroalkane having 3-6 carbon atoms, a fluorocycloalkane having 3-6 carbon atoms, a compound in which a hydrogen atom of the fluoroalkane is substituted with a chlorine atom, and a compound in which a hydrogen atom of the fluorocycloalkane is substituted with a chlorine atom.

＜5＞

The uneven pattern drying composition according to any one of < 1 > - < 3 >, wherein the sublimable substance is naphthalene, 1,2,2,3,3, 4-heptafluorocyclopentane, 1-dichlorooctafluorocyclopentane, 1,2,2,3,3,4, 4-octafluorocyclohexane, or perfluorocyclohexane.

＜6＞

The uneven pattern drying composition according to < 5 >, wherein the sublimable substance is 1,1,2,2,3,3, 4-heptafluorocyclopentane.

＜7＞

The uneven pattern drying composition according to any one of < 1 > -6 >, wherein a content of the sublimable substance is 5-55% by mass with respect to a total mass of the uneven pattern drying composition.

＜8＞

The uneven pattern drying composition according to any one of < 1 > -7 >, wherein the solvent is at least 1 selected from hydrocarbons optionally having at least one of a fluorine atom and a chlorine atom, ethers optionally having at least one of a fluorine atom and a chlorine atom, and alcohols optionally having at least one of a fluorine atom and a chlorine atom.

＜9＞

The uneven pattern drying composition according to < 8 >, wherein the solvent is hexane, trans-1-chloro-3, 3, 3-trifluoropropene, cis-1-chloro-3, 3, 3-trifluoropropene, diethyl ether, tetrahydrofuran, 1,1,1,3,3, 3-hexafluoro-2-methoxypropane, or 1,1,1,2,2,3,3,4, 4-nonafluorobutyl methyl ether.

＜10＞

A method for manufacturing a substrate having a concave-convex pattern on a surface thereof, comprising:

a step (I) for supplying a drying composition containing a sublimable substance and a solvent in a solution state to the recessed portions of the uneven pattern;

a step (II) of drying the solvent in the recess to solidify the sublimable substance; and

a step (III) of sublimating the sublimable substance; and is

The boiling point of the solvent is lower than the boiling point or sublimation point of the sublimable substance by 5 ℃ or more under 1 atmosphere,

the boiling point of the solvent is 75 ℃ or lower under 1 atmosphere.

＜11＞

The method of manufacturing a substrate having a surface with a concavo-convex pattern as set forth in < 10 >, which comprises a step of purifying the sublimable substance before the step (I).

Examples

(example 1)

As the sublimable substance, 2.0g of 1,1,2,2,3,3, 4-Heptafluorocyclopentane (HFCPA) was used. Cis-1-chloro-3, 3, 3-trifluoropropene (1233Z) was used as a solvent, and dissolved and diluted so that the total amount was 10.0 g. The solution was used as a composition for drying. As the HFCPA, "Zeorora H" manufactured by Zeon Corporation was used.

A silicon substrate having a concave-convex pattern formed on the surface thereof with a plurality of substantially cylindrical convex portions having an aspect ratio of 22 and a pattern width of 19nm in cross-sectional view at a pitch of 90nm (total distance between the widths of the convex portions and adjacent intervals of the convex portions) was cut into a size of 1cm × 1.5cm and used as a sample for evaluation. The samples for evaluation were previously passed through UV/O₃The substrate was irradiated and dry-cleaned. The evaluation sample was set in a spin coater, and 2-propanol was supplied so that the liquid (2-propanol) was held in the recessed portions of the pattern. Then, the drying composition in a solution state is dropped to replace the 2-propanol (residual liquid) with the drying composition (step (I)). Then, the evaluation sample was rotated by a spin coater, and formation of a solidified product (a solid film of a sublimable substance) was visually confirmed (step (II)). Further, the rotation is continued until the solidified material disappears by visual observation (step (III)). The steps (I) to (III) are carried out at 23 to 24 ℃ under a nitrogen atmosphere of 1 atm.

The collapse prevention property of the pattern was evaluated by observing the sample for evaluation obtained after the process (III) with a Scanning Electron Microscope (SEM) (SU8010, manufactured by Hitachi High-Technologies Corporation). The results are shown in Table 1 below. The "pattern collapse rate" is obtained by taking an electron microscope image (secondary electron image) of the central portion of the evaluation sample at a magnification of 500 to 600 projections entering the field of view using SEM, counting the projections that have collapsed in the image, and calculating the percentage of the number of projections in the field of view. The numerical values are rounded by so-called rounding in units of 10 according to JIS Z8401.

(examples 2 to 15)

HFCPA was used as a sublimable substance in the same manner as in example 1, and the preparation and evaluation of evaluation samples were performed in the same manner as in example 1, with the concentrations of the solvent and the sublimable substance changed as shown in table 1 below. The results are shown in Table 1 below.

Comparative examples 1 to 10

HFCPA was used as a sublimable substance in the same manner as in example 1, and the preparation and evaluation of evaluation samples were performed in the same manner as in example 1, with the concentrations of the solvent and the sublimable substance changed as shown in table 2 below. The results are shown in Table 2 below.

In comparative example 1, only a solvent was used as the drying composition without using a sublimable substance. In comparative example 2, a melt of a sublimable substance was used as the drying composition without using a solvent. In comparative examples 3 to 9, a composition was used as the drying composition, which was not satisfied by the above condition (1) 'that the boiling point of the solvent was lower than the boiling point or sublimation point of the sublimable substance by 5 ℃ or more under 1 atmospheric pressure' and the condition (2) 'that the boiling point of the solvent was 75 ℃ or less under 1 atmospheric pressure'. In comparative example 10, a composition satisfying the above condition (1) but not satisfying the above condition (2) was used as the drying composition.

(example 16, comparative examples 11 to 15)

Naphthalene was used as a sublimable substance, the concentrations of the solvent and the sublimable substance were changed as shown in table 3 below, the steps (I) and (II) were performed in the same manner as in example 1, and the sample for evaluation was moved onto a heating plate at 50 ℃. The steps (I) and (II) are carried out at 23 to 24 ℃ under a nitrogen atmosphere of 1atm, and the step (IIIb) is carried out at 50 ℃ under a nitrogen atmosphere of 1 atm. The evaluation samples after completion of the step (IIIb) were evaluated in the same manner as in example 1, and the results are shown in table 3 below.

In comparative example 11, only a solvent was used as the drying composition without using a sublimable substance. In comparative example 12, a melt of a sublimable substance was used as a drying composition without using a solvent. In comparative examples 13 to 15, a composition satisfying the above condition (1) but not satisfying the above condition (2) was used as the drying composition.

(examples 17 to 21, comparative example 16)

DCOFCPA was used as the sublimable substance, and the preparation and evaluation of the evaluation samples were carried out in the same manner as in example 1, with the concentrations of the solvent and the sublimable substance changed as shown in table 4 below. The results are shown in Table 4 below. In comparative example 16, a composition that does not satisfy both of the above conditions (1) and (2) was used as the drying composition.

(examples 22 to 37, comparative example 17)

A sublimation agent (sublimable substance) was mixed with a solvent so that the concentration (mass%) of the sublimation agent was as shown in table 7, to prepare a composition for drying. The preparation and evaluation of the evaluation samples were carried out in the same manner as in example 1.

(examples 38 to 40)

A composition for drying was prepared by mixing a sublimation agent 1 and a sublimation agent 2 (sublimable substances) in a solvent 1 and/or a solvent 2 so as to have a mixing ratio (mass%) shown in table 8. The preparation and evaluation of the evaluation samples were carried out in the same manner as in example 1.

Tables 1 to 4, 7 and 8 below show the kind of solvent used in each of examples and comparative examples, the boiling point of the sublimable substance or the difference between the boiling point of the solvent and the boiling point of the sublimable substance, the concentration of the sublimable substance in the drying composition, the replaceability (the amount of the drying composition required in step (I)), the solidification time (the time taken in step (II)), the sublimation time (the time taken in step (III) or step (IIIb)), and the pattern collapse rate.

The abbreviation, boiling point and vapor pressure of the solvent are shown in Table 5 below.

The abbreviation, freezing point, boiling point and vapor pressure of the sublimable substance are shown in table 6 below.

In all examples and comparative examples, the sublimable substance was previously purified.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

TABLE 5

In the absence of any comment, the vapor pressure is the value at 20 ℃. The boiling point is a value at atmospheric pressure.

[ Table 6]

TABLE 6

[ Table 7]

[ Table 8]

TABLE 8

This application claims priority based on japanese application patent application No. 2019 @ -051796, filed on 3/19/2019, the disclosure of which is incorporated herein in its entirety.