JP7345317B2 - Filler and substrate treatment method - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to fillers and methods for treating substrates.

In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, advances in lithography technology have led to rapid miniaturization of patterns. As patterns become finer, the aspect ratio of the patterns tends to increase.

On the other hand, in semiconductor manufacturing processes, contamination of particles and the like causes a reduction in manufacturing yield. Therefore, in order to remove particles and the like attached to the substrate, the substrate is cleaned using a rinsing liquid. After cleaning the substrate on which a pattern has been formed with a rinsing liquid, the rinsing liquid is removed by drying the substrate, but at this time, the pattern on the surface of the substrate may collapse due to the capillary force of the rinsing liquid remaining in the pattern. This may occur.

In order to solve this problem of pattern collapse, for example, in Patent Document 1 and Patent Document 2, after cleaning a substrate on which a concavo-convex pattern is formed with a rinsing liquid, the rinsing liquid remaining in the concave portions of the pattern is removed using camphor, A method of replacing the liquid with a filling treatment liquid containing a sublimable substance such as naphthalene, filling the recesses of the pattern, precipitating the sublimable substance from the treatment liquid, and removing the precipitated solid sublimable substance by sublimation. is proposed. It is said that this makes it possible to reduce pattern collapse due to the action of capillary force.

Japanese Patent Application Publication No. 2012-243869 Japanese Patent Application Publication No. 2013-42093

However, in the method using a general sublimable substance as disclosed in Patent Document 1 and Patent Document 2 mentioned above, failure to fill the sublimable substance in the recesses of the pattern frequently occurs, resulting in pattern collapse on the substrate surface. The suppressive effect was not sufficient.

The present invention has been made in view of the above circumstances, and the present invention provides a filler that is excellent in suppressing pattern collapse and has good film-forming and sublimation properties when treating the surface of a substrate on which an uneven pattern is formed. An object of the present invention is to provide a method for processing a substrate using a filler.

In order to solve the above problems, the present invention employs the following configuration.
That is, the first aspect of the present invention is a filler that, when solidified, fills the recesses of a substrate having an uneven pattern formed on the surface, the (N) component being from the group consisting of imidazole and imidazole derivatives. It is a filler containing at least one selected one.

A second aspect of the present invention is a method for treating a substrate, the surface of a substrate having an uneven pattern formed thereon using the filler according to the first aspect. A method of processing a substrate, comprising a solidified film filling step of solidifying the pattern and filling at least the inside of the concave portion of the pattern with the solidified film, and a solidified film removing step of removing the solidified film.

According to the present invention, it is possible to provide a filler that is excellent in suppressing pattern collapse and has good film-forming properties and sublimation properties, and a method for treating a substrate using the filler.

FIG. 2 is a diagram schematically showing a substrate processing method according to the present embodiment.

(filler)
When solidified, the filler of this embodiment fills the recesses of a substrate having an uneven pattern formed on its surface.
The filler of this embodiment is typically used to replace the rinsing liquid remaining in the recesses of the pattern after cleaning a substrate with a pattern of projections and recesses on the surface with a rinsing liquid, and to fill the recesses. It is a filler used in

The filler of this embodiment contains component (N): at least one selected from the group consisting of imidazole and imidazole derivatives.

<(N) component: imidazole and imidazole derivative>
Component (N) in this embodiment is imidazole and imidazole derivatives, and is a sublimable substance. Since the filler of this embodiment contains the (N) component, both film-forming properties and sublimation properties are good.
Here, the imidazole derivative is a compound having a ring structure containing nitrogen atoms at the 1st and 3rd positions on a 5-membered ring, and some or all of the hydrogen atoms bonded to the imidazole ring are substituted with an alkyl group, etc. means a compound etc.

Among the above, component (N) preferably includes a compound represented by the following general formula (n1).

［式中、Ｒａ～Ｒｃは、それぞれ独立に、水素原子、ハロゲン原子、又は置換基を有してもよい炭化水素基である。Ｒｂ及びＲｃは、互いに結合し、環を形成してもよい。］

[In the formula, Ra to Rc are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group which may have a substituent. Rb and Rc may be bonded to each other to form a ring. ]

In formula (n1), Ra to Rc each independently represent a hydrogen atom, a halogen atom, or a hydrocarbon group which may have a substituent.
Examples of the halogen atom in Ra to Rc include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

Examples of the hydrocarbon group in Ra to Rc include a linear or branched alkyl group, or a cyclic hydrocarbon group.

The linear alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and even more preferably 1 to 5 carbon atoms. Specific examples include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, and the like.

The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, 1,1-diethylpropyl group, and 2,2-dimethylbutyl group.

The above-mentioned cyclic hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group.
As the aliphatic hydrocarbon group which is a monocyclic group, a group obtained by removing one hydrogen atom from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane.
The aliphatic hydrocarbon group which is a polycyclic group is preferably a group obtained by removing one hydrogen atom from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms. Examples include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.
This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms.
Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms; Can be mentioned. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

Examples of substituents that the hydrocarbon group in Ra to Rc may have include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a nitro group, an amino group, a thiol group, and the like.

Rb and Rc may be bonded to each other to form a ring.
The ring formed by combining Rb and Rc with each other is an aromatic hydrocarbon ring such as benzene, naphthalene, anthracene, phenanthrene; a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom. Examples include aromatic heterocycles. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

When Rb and Rc are bonded to each other to form a ring, among the above, it is preferable that they form an aromatic hydrocarbon ring, and it is more preferable that they form benzene.

Among the above, component (N) more preferably contains a compound represented by the following general formula (n1-1).

［式中、Ｒ^１～Ｒ^５は、それぞれ独立に、水素原子、ハロゲン原子、又は炭素原子数１～５のアルキル基である。］

[In the formula, R ¹ to R ⁵ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. ]

In formula (n1-1), R ¹ to R ⁵ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms.
The halogen atom is the same as the halogen atom in Ra to Rc in the above-mentioned formula (n1).
The alkyl group having 1 to 5 carbon atoms is the same as the linear or branched alkyl group having 1 to 5 carbon atoms in Ra to Rc in formula (n1) described above.

Among the above components, the component (N) in this embodiment is more preferably imidazole or benzimidazole, and from the viewpoint of film-forming properties, benzimidazole is particularly preferred.

The (N) component in this embodiment may be used alone or in combination of two or more.

The content of the component (N) is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly 8% by mass or more, based on the total amount of filler (100% by mass). preferable.
On the other hand, the content of the (N) component is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and 15% by mass or less based on the total amount of filler (100% by mass). is particularly preferred.
The content of the (N) component in this embodiment is preferably, for example, 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 30% by mass or less, based on the total amount of filler (100% by mass). It is more preferably 5% by mass or more and 20% by mass or less, particularly preferably 8% by mass or more and 15% by mass or less.

If the content of the (N) component is at least the above-mentioned preferable lower limit, the effect of suppressing pattern collapse will be more excellent.
If the content of the (N) component is below the preferable upper limit above, the removability of the solidified film will be better. Moreover, even if it is below the above-mentioned preferable upper limit, the film formability is sufficiently excellent.

The filler in this embodiment may consist only of the (N) component.
On the other hand, it may be used in combination with components other than the (N) component (other components).

<Other ingredients>
The filler of this embodiment can contain other components other than the above-mentioned components within a range that does not impede the object of the present invention.
Other components in the filler of this embodiment include component (S): solvent, surfactant, and the like.

≪(S) component: solvent≫
Among the (S) components, the filler of the present embodiment preferably contains (S1) component: a polar organic solvent from the viewpoint of compatibility with the (N) component.

(S1) Component: Polar organic solvents include protic polar solvents such as glycol solvents, glycol ether solvents, and monoalcohol solvents; ester solvents, amide solvents, sulfoxide solvents, sulfone solvents, and nitrile solvents. Examples include aprotic polar solvents such as.

Specific examples of the glycol solvent include ethylene glycol, propylene glycol, hexylene glycol, and the like.
Specific examples of glycol ether solvents include methyl diglycol, ethyl diglycol, butyl diglycol, 3-methoxy-3-methyl-1-butanol, diisopropylene glycol monomethyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl. Examples include ether.
Specific examples of the monoalcoholic solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol.

Specific examples of the ester solvent include ethyl acetate, n-propyl acetate, isobutyl acetate, ethyl lactate, diethyl oxalate, diethyl tartrate, β-propiolactone, γ-butyrolactone, and ε-caprolactone.
Specific examples of the amide solvent include N-methylpyrrolidone, N-ethylpyrrolidone, N-butylproldone, dimethylformamide, and dimethylacetamide.
Specific examples of the sulfoxide solvent include dimethyl sulfoxide and the like.
Specific examples of the sulfone solvent include sulfolane and the like.
Specific examples of the nitrile solvent include acetonitrile and the like.

Among the above components, the component (S1) is preferably a protic polar solvent, and more preferably a monoalcoholic solvent. Specifically, isopropanol is preferred.

The component (S1) in this embodiment may be used alone or in combination of two or more.
The content of the component (S1) is not particularly limited, and is appropriately set according to the thickness of the coating film at a concentration that allows the filler to be coated on the substrate.
The content of component (S1) is preferably 10 to 99% by mass, more preferably 30 to 95% by mass, and even more preferably 50 to 92% by mass, based on the total amount of filler (100% by mass).

The mixing ratio (mass ratio) of the (N) component and (S1) component (N) component:(S1) component is preferably 1:99 to 50:50, more preferably 5:95 to 30:70, and 8 :92 to 20:80 is more preferable.

The proportion of the component (S1) in the entire component (S) in this embodiment is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 95% by mass or more. Note that it may be 100% by mass.

The (S) component in this embodiment may contain a solvent other than the above-mentioned (S1) component. Examples of solvents other than the component (S1) include water, nonpolar organic solvents (hydrocarbon solvents, etc.), and the like.
As the water, pure water, ion exchange water, etc. can be used.
Specific examples of the hydrocarbon solvent include toluene, benzene, xylene, hexane, heptane, octane, and the like.

≪Surfactant≫
Examples of the surfactant include fluorosurfactants and silicone surfactants.

Specific examples of fluorosurfactants include BM-1000, BM-1100 (all manufactured by BM Chemie), Megafac F142D, Megafac F172, Megafac F173, and Megafac F183 (all manufactured by DIC). , Florado FC-135, Florado FC-170C, Florado FC-430, Florado FC-431 (all manufactured by Sumitomo 3M), Surflon S-112, Surflon S-113, Surflon S-131, Surflon S-141, Surflon Examples include commercially available fluorine-based surfactants such as S-145 (all manufactured by Asahi Glass Co., Ltd.), SH-28PA, SH-190, SH-193, SZ-6032, SF-8428 (all manufactured by Toray Silicone Co., Ltd.) .

Specific examples of silicone surfactants include unmodified silicone surfactants, polyether-modified silicone surfactants, polyester-modified silicone surfactants, alkyl-modified silicone surfactants, and aralkyl-modified silicone surfactants. Active agents, reactive silicone surfactants, and the like can be preferably used.
As the silicone surfactant, commercially available silicone surfactants can be used. Specific examples of commercially available silicone surfactants include Paintad M (manufactured by Dow Corning Toray), Topeka K1000, Topeka K2000, Topeka K5000 (all manufactured by Takachiho Sangyo Co., Ltd.), and XL-121 (polyether-modified silicone type). (surfactant, manufactured by Clariant), BYK-310 (polyester-modified silicone surfactant, manufactured by BYK-Chemie), and the like.

From the viewpoint of removability, the filler of this embodiment preferably contains the (N) component and the (S1) component, and is more preferably a solution in which the (N) component is dissolved in the (S1) component. The concentration of the (N) component in this solution is preferably 1 to 50% by mass, more preferably 3 to 30% by mass, and even more preferably 5 to 15% by mass.

Since the filler of the present embodiment described above contains the (N) component, it is possible to suppress pattern collapse when processing the surface of a substrate on which an uneven pattern is formed. In addition, the filler of this embodiment contains the (N) component and therefore has good film-forming properties and sublimation properties.

(Substrate processing method)
The substrate processing method of the present embodiment is a substrate processing method in which the surface of the substrate on which an uneven pattern is formed is treated using the filler according to the first aspect described above, and the filling agent according to the first aspect is This method of processing a substrate includes a solidified film filling step of solidifying an agent and filling at least the inside of the concave portion of the pattern with a solidified film, and a solidified film removing step of removing the solidified film.

<Substrate processing method according to first embodiment>
The substrate processing method according to the first embodiment includes a rinsing step of rinsing the surface of the substrate having a pattern of concave and convex portions formed thereon with a rinsing liquid, and a rinsing step of rinsing the rinsing liquid remaining in the recesses of the pattern in the above-mentioned step. a substitution filling step of replacing the filler with the filler according to the first aspect and filling the recesses of the pattern; a solidified film filling step of solidifying the filler and filling at least the inside of the recesses of the pattern with a solidified film; The method of processing a substrate includes a solidified film removing step of removing the solidified film.
The substrate processing method according to the first embodiment will be described in detail using FIG. 1.

FIG. 1(a) is a diagram schematically showing a substrate on which an uneven pattern is formed. An uneven pattern 11 (a pattern including a plurality of pillars) is formed on the surface of the substrate 1, and includes a concave portion 11a of the pattern and a convex portion 11b of the pattern.

The substrate 1 is not particularly limited, and any conventionally known substrate may be used, such as a substrate for electronic components, a substrate on which a predetermined wiring pattern is formed, and the like. More specifically, examples include silicon wafers, metal substrates such as copper, chromium, iron, and aluminum, and glass substrates. As the material for the wiring pattern, for example, copper, aluminum, nickel, gold, etc. can be used.
Among the above, the substrate 1 is preferably a silicon wafer (silicon substrate). The silicon substrate may have a silicon oxide film formed on its surface, such as a natural oxide film, a thermal oxide film, or a vapor phase synthesis film (such as a CVD film), and may have a pattern formed on the silicon oxide film. It may be.

Formation of such a pattern can be performed using a known method. For example, a resist film is formed on a substrate using a known resist composition, the resist film is developed and exposed to form a resist pattern, and then the substrate is etched using the resist pattern as a mask to form a pattern. can be formed.

[Rinse process]
The rinsing process is a process of rinsing the surface of the substrate 1 with a rinsing liquid 20, which will be described later.
FIG. 1(b) is a diagram showing the surface of the substrate 1 in contact with the rinsing liquid 20. As shown in FIG.
The rinsing method is not particularly limited, and any method commonly used for cleaning substrates in semiconductor manufacturing processes can be adopted. Examples of such methods include a spin coating method, a dipping method, a spray method, and a piling method (paddle method), which will be described later. Among these, the spin coating method is preferable as the rinsing method. An example of the rotational speed of the spin is 100 rpm or more and 5000 rpm or less.

The spin coating method is a method in which a substrate is rotated using a spin coater or the like, and a rinsing liquid is dripped or sprayed onto the rotated substrate.
The immersion method (dip method) is a method in which the substrate is immersed in a rinsing liquid.
The spray method is a method in which a substrate is transported in a predetermined direction and a rinsing liquid is sprayed into the space.
The liquid piling method (paddle method) is a method in which the rinsing liquid is piled up on the substrate by surface tension and left at rest for a certain period of time.

- Rinsing liquid The rinsing liquid 20 used in the rinsing process is not particularly limited, and those commonly used in the rinsing process of semiconductor substrates can be used. Examples of the rinse liquid 20 include those containing the above-mentioned polar organic solvent and non-polar organic solvent.
The rinsing liquid 20 may contain water instead of or together with the organic solvent.
The rinse liquid 20 may contain known additives and the like. Examples of known additives include the above-mentioned fluorosurfactants and silicone surfactants.

[Replacement filling process]
The replacement filling step is a step of replacing and filling the rinsing liquid 20 remaining in the concave portions 11a of the pattern with the filler 21 according to the first embodiment described above.
FIG. 1(c) is a diagram in which the rinsing liquid 20 remaining in the concave portions 11a of the pattern is replaced with the filler 21, and the inside of the concave portions 11a of the pattern and the top of the convex portions 11b of the pattern are filled and covered with the filler 21. It is.
Here, examples of the filler 21 include a melt of the (N) component and a mixture of the (N) component and other optional components (such as a mixture of the (N) component and the (S) component).

The rinsing liquid 20 remaining in the concave portions 11a of the pattern is replaced with the filler 21 according to the first aspect described above, and the filler 21 is filled by a spin coating method, an immersion method (dipping method), or a spray method. , a method of contacting the inside of the concave portion 11a of the pattern using a liquid piling method (paddle method) or the like.

When the filler 21 is solid at room temperature, the temperature at which the filler 21 is brought into contact with the recesses 11a of the pattern is heated to a temperature equal to or higher than the melting point of the filler 21. For example, in the case of a melt of component (N), the temperature is preferably 10° C. higher than the melting point of component (N).
On the other hand, if the filler 21 is a mixture of the (N) component, the (S) component, and other optional components, and is liquid at room temperature, it can be stored at around room temperature (25°C) without setting any particular temperature conditions. The process may be performed.

[Solidified membrane filling process]
The solidified film filling process is a process of solidifying the filler 21 and filling the inside of the concave portion 11a of the pattern with the solidified film 22.
FIG. 1(d) is a diagram in which the inside of the concave portion 11a of the pattern and the top of the convex portion 11b of the pattern are filled and covered with the solidified film 22.

As a method for solidifying the filler 21, when the filler 21 consists only of the (N) component, the filler ((N) component) can be solidified by cooling to below the freezing point of the (N) component. can.

When the filler 21 is a mixture of the (N) component and the (S) component, or a mixture of the (N) component, the (S) component, and other optional components, the (S) component is removed by the drying process. By removing it, the filler (component (N)) can be solidified.
As the drying process, known methods such as spin drying, heat drying, hot air drying, vacuum drying, etc. can be used. For example, spin drying under blowing with an inert gas (such as nitrogen gas) is preferably exemplified. Note that the drying step is carried out under conditions such that the (S) component evaporates but the (N) component is maintained at a temperature that does not sublimate.

[Solidified film removal process]
The solidified film removal process is a process of removing the solidified film 22.
As a method for removing the solidified film 22, it is preferable to sublimate the solidified film 22 ((N) component).
FIG. 1E is a diagram showing a process in which the solidified film 22 is sublimated and removed.
FIG. 1(f) is a diagram with the solidified film 22 removed.

The temperature at which the solidified film 22 ((N) component) is sublimated is lower than the melting point of the solidified film 22 ((N) component), and may be a temperature at which the solidified film 22 ((N) component) does not melt. Although not particularly limited, it is preferable to sublimate the solidified film 22 ((N) component) at a temperature that is 10 to 20° C. lower than the melting point of the (N) component, for example.
Moreover, the above-mentioned sublimation may be performed under reduced pressure.

Further, as a modification of the solidified film removal process, for example, a mode may be mentioned in which the solidified film 22 ((N) component) is heated to a temperature at which it decomposes, and the solidified film 22 ((N) component) is removed. Even in such an embodiment, reduced pressure conditions can be employed.

<Other embodiments>
The substrate processing method according to the first embodiment described above had a rinsing step and a substitution filling step, but the substrate processing method of this embodiment has a rinsing step and a substitution filling step. Alternatively, the method may include rinsing with the filler according to the first aspect, filling the recesses of the pattern with a solidified film, and removing the solidified film.
That is, as another embodiment, there is provided a method for treating a substrate, in which the surface of a substrate having an uneven pattern formed on the surface is treated using the filler according to the first aspect described above, the method comprising: a rinsing step of rinsing the surface of the substrate using a filler; a solidified film filling step of solidifying the filler and filling at least the inside of the recess of the pattern with a solidified film; and a solidifying step of removing the solidified film. This is a substrate processing method, which includes a film removal step.

Although a substrate on which a pattern including a plurality of pillars is formed has been described in FIG. 1(a), the shape of the uneven pattern is not particularly limited, and may be a pattern shape commonly formed in a semiconductor manufacturing process. I can do it. The pattern shape may be a line pattern, a hole pattern, or a pattern including a plurality of pillars. The pattern shape is preferably a pattern including a plurality of pillars. The shape of the pillar is not particularly limited, and examples thereof include a cylindrical shape, a polygonal prism shape (such as a quadrangular prism shape), and the like.

In FIGS. 1(c) and 1(d), the filler 21 and the solidified film 22 fill and cover the concave portions 11a and the convex portions 11b of the pattern, but the present invention is not limited to this, and at least It is sufficient that the concave portions 11a of the pattern are filled with the filler 21 and the solidified film 22 at a height from the substrate 1 to the middle of the convex portions 11b of the pattern.

The substrate processing method of this embodiment described above is a method of processing the surface of a substrate on which an uneven pattern is formed using the filler according to the first aspect described above. Since the filler according to the first aspect, which has good film-forming properties and sublimation properties, is used, pattern collapse can be suppressed. Moreover, since the filler according to the first aspect described above has good film-forming properties and sublimation properties, it is also excellent in productivity.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

<Preparation of filler>
(Examples 1 and 2, Comparative Examples 1 to 4)
Each component shown in Table 1 was mixed to prepare a filler for each example.

In Table 1, the abbreviations have the following meanings. The numerical value in [ ] is the compounding amount (mass %).
IPA: Isopropyl alcohol PM: Propylene glycol monomethyl ether Polystyrene: Number average molecular weight (Mn) determined by GPC measurement is 2000, molecular weight dispersity (Mw/Mn) is 1.10

[Evaluation of film formability]
<Formation of solidified film>
A 6-inch silicon wafer was used as the substrate.
The fillers of each example were applied onto the silicon wafer using a spin coating method to form a solidified film on the silicon wafer. Specifically, the filler of each example was discharged onto the silicon wafer at a SLOPE of 10 seconds and a speed of 1500 rpm for 10 seconds. It was then dried with a spin dry for 30 seconds and edge rinsed with isopropyl alcohol for 10 seconds. Next, it was further dried under the conditions of spin drying for 10 seconds and SLOPE for 10 seconds. Thereafter, the filler was left to stand until the filler was solidified and a solidified film was formed on the silicon wafer (temperature: 25° C.).

≪Evaluation of solidification time≫
In the above <Formation of a solidified film>, the time from when the spin stops when the filler of each example is applied by the spin coating method until the entire area of the filler of each example coated on the silicon wafer is solidified. was measured. The completion of solidification was determined by visual inspection and observation using an optical microscope, and the solidification time was evaluated based on the following criteria. The results are shown in Table 2.
○: Solidification is completed within 5 minutes ×: Solidification is not completed within 5 minutes From the viewpoint of productivity, the shorter the solidification time, the better, and 5 minutes or less was evaluated as ○.

≪Evaluation of filling properties of solidified membrane≫
The solidified film formed in the above <Formation of solidified film> was observed visually and with an optical microscope (5x magnification), and the filling properties of the solidified film were evaluated using the following evaluation criteria. The results are shown in Table 2.
〇: Substrate exposure is not observed visually and under optical microscope observation. △: Substrate exposure is not observed visually, but substrate exposure is confirmed under optical microscope observation. ×: Substrate exposure is observed visually in the coated area.

[Evaluation of sublimability]
The solidified film formed in the above <Formation of solidified film> was heated at a temperature 20 degrees lower than the respective melting points of each (N) component and other components (hereinafter referred to as (N) component, etc.) under normal pressure. The sublimation process of the solidified film was visually observed. The time from the start of heating to the completion of sublimation was measured, and the sublimation time was evaluated using the following evaluation criteria. The results are shown in Table 2.
○: Sublimation is completed within 5 minutes ×: Sublimation is not completed within 5 minutes From the viewpoint of productivity, the shorter the sublimation time, the better, and 5 minutes or less was evaluated as ○.

[Evaluation of pattern collapse suppression effect]
<Substrate processing>
[Solidified membrane filling process]
A silicon pattern chip (2 cm x 2 cm) having a pillar structure was used as the substrate.
The filler of each example was applied to the surface of the silicon pattern chip by a spin coating method. Next, the filler was dried by spin drying for 30 seconds to solidify the filler of each example in the recess of the silicon pattern chip, and the recess of the silicon pattern chip was filled with each solidified film.

[Solidified film removal process]
In the above [filling process], the solidified film of each (N) component etc. filling the recesses of the silicon pattern chip is heated at a temperature 20 degrees lower than the melting point of each (N) component etc. under normal pressure, Each (N) component etc. was sublimed and the solidified film of each (N) component etc. was removed.

≪Evaluation of collapse rate≫
The silicon pattern chip treated by the above <Substrate processing method> was observed with a SEM, the incidence of pattern collapse (collapse rate) of the silicon pattern chip was calculated, and the collapse rate was evaluated based on the following criteria. The results are shown in Table 2.
Note that when the above substrate was treated with only isopropyl alcohol, the collapse rate was 100%.
〇: Collapse rate is less than 30% ×: Collapse rate is 30% or more

As shown in Table 2, the fillers of Examples 1 and 2 were also more effective in suppressing pattern collapse than the fillers of Comparative Examples 1 to 4. Furthermore, the solidification time was short, the solidified film had high filling properties, and the sublimation time was short.

On the other hand, the filler of Comparative Example 1 has an excellent effect of suppressing pattern collapse, but the solidification time and sublimation time are 5 minutes or more, and compared to the fillers of Examples 1 and 2, the filler has poor film formability and sublimation property. The productivity is poor in practical terms.
The fillers of Comparative Example 2 and Comparative Example 3 were inferior to the fillers of Example 1 and Example 2 in suppressing pattern collapse. In addition, some visible substrate exposures were observed here and there.
The filler of Comparative Example 4 did not sublimate even after heating for 1 hour in the solidified film removal process, and the filler remained within the pattern, resulting in poor productivity in practice.

From the above, it can be confirmed that the filler of this embodiment has an excellent effect of suppressing pattern collapse and also has good film-forming properties and sublimation properties.

DESCRIPTION OF SYMBOLS 1... Substrate 11... Uneven pattern 11a... Recessed part of pattern 11b... Convex part of pattern 20... Rinse liquid 21... Filler 22... Solidified film

Claims (5)

A filler that, when solidified, fills the recesses of a substrate with an uneven pattern formed on its surface with a solidified film , and is removed by sublimating the solidified film, the filler comprising:
Component (N): A filler containing at least one member selected from the group consisting of imidazole and imidazole derivatives. The filler according to claim 1, wherein the component (N) includes a compound represented by the following general formula (n1).

[In the formula, Ra to Rc are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group which may have a substituent. Rb and Rc may be bonded to each other to form a ring. ] The filler according to claim 2, wherein the component (N) includes a compound represented by the following general formula (n1-1).

[In the formula, R ¹ to R ⁵ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. ] The filler according to any one of claims 1 to 3, further comprising component (S1): a polar organic solvent. 5. A method for treating a substrate, comprising treating the surface of a substrate having an uneven pattern formed on the surface using the filler according to any one of claims 1 to 4,
a solidified film filling step of solidifying the filler and filling at least the inside of the recess of the pattern with the solidified film;
A method for processing a substrate, comprising a solidified film removing step of removing the solidified film by sublimating the solidified film.

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