JP7123668B2 - SUBSTRATE WITH RESIST MULTILAYER FILM AND PATTERN FORMATION METHOD - Google Patents

Description

The present invention relates to a method of forming a wiring pattern on a semiconductor device manufacturing substrate, and a substrate with a resist multilayer film used in the method.

Conventionally, the advancement of the processing capability of semiconductor devices has been driven by the miniaturization of pattern dimensions due to the shortening of the wavelength of the light source in lithography technology. However, in recent years, since the speed of wavelength shortening after the ArF light source has been slowing down, there has been a demand for higher processing performance of semiconductor devices in place of miniaturization. As one of the methods, there has been proposed a semiconductor device with high processing capability in which three-dimensional transistors capable of operating at a higher speed than planar transistors are densely arranged. A substrate for manufacturing such a semiconductor device (hereinafter referred to as a substrate) has a three-dimensional structure that has undergone a stepped process that is more complicated than conventional substrates. Therefore, when a pattern is formed by a pattern formation method using a single-layer photoresist that has been applied to form a conventional planar transistor, the photoresist film follows the steps formed during substrate processing. As a result, steps are generated on the surface of the photoresist film, and as a result, a flat resist film cannot be obtained. As a result, when exposing and patterning the photoresist, the photoresist cannot be accurately focused, resulting in a decrease in substrate processing yield. New materials and methods are required to prevent this.

As one of the methods for solving such problems, there is a multi-layer resist method. In this method, a lower layer film with high planarization performance is used to flatten a substrate with steps, and a photoresist film is formed on this flattened film. can be prevented. Furthermore, in this method, if a lower layer film having different etching selectivities is selected with respect to the upper layer photoresist film and the substrate, after forming a pattern in the resist upper layer film, intermediate etching is performed by dry etching using the resist upper layer film pattern as a dry etching mask. It is possible to transfer the pattern to the film, and then transfer the pattern to the substrate to be processed by dry etching using the underlying film as a dry etching mask.

As the multi-layer resist method, a three-layer resist method is generally used, which can be performed using a general resist composition used in the single-layer resist method. For example, an organic resist underlayer film having high flatness and sufficient dry etching resistance for substrate processing is formed on a substrate to be processed, and a silicon-containing resist underlayer film is formed thereon as an intermediate film (hereinafter referred to as a silicon-containing resist underlayer film). (referred to as a resist intermediate film), and a photoresist film is formed thereon as a resist upper layer film. For dry etching with fluorine-based gas plasma, the organic resist upper layer film has a good etching selectivity with respect to the silicon-containing resist intermediate film, so the resist pattern should be dry-etched with fluorine-based gas plasma. can be transferred to the silicon-containing resist intermediate film at . Furthermore, in dry etching with oxygen-based gas plasma, the silicon-based resist intermediate film has a good etching selectivity with respect to the organic resist underlayer film. It can be transferred to the organic resist underlayer film by using etching. According to this method, the composition for forming a resist upper layer film, which is difficult to form a pattern with a sufficient thickness for directly processing a substrate to be processed, or the composition for forming a substrate, has sufficient dry etching resistance. Even if a resist upper layer film forming composition is used, if the pattern can be transferred only to the silicon-containing film, an organic resist lower layer film pattern having sufficient dry etching resistance for processing can be obtained. Pattern transfer by such dry etching does not cause problems such as pattern collapse due to friction caused by developer during resist development, so even a high aspect ratio can function sufficiently as a dry etching mask. A pattern of an organic film having a thickness corresponding to the desired thickness can be obtained. By using the pattern of the organic resist underlayer film thus formed as a dry etching mask, it becomes possible to transfer the pattern to a substrate having a three-dimensional transistor structure with complicated steps. As the organic resist underlayer film as described above, many have already been known, such as those described in Patent Document 1, for example.

Generally, in the three-layer resist method, it is necessary to leave a silicon-containing resist intermediate film with a thickness of several nanometers on the organic resist underlayer film pattern in pattern transfer by dry etching to the organic resist underlayer film in order to stabilize processing dimensions. be. The remaining silicon is etched away by dry etching gas for processing the substrate while the pattern is being transferred to the substrate using the organic resist underlayer film pattern as a mask. does not remain on top. Therefore, even if the organic resist underlayer film pattern remaining after processing the substrate is dry-etched (ashed) or wet-removed, the silicon content will not remain as a residue on the substrate.

As described above, the multi-layer resist method is used for a wide range of substrate processing because it can be applied to a substrate having a large step as a substrate processing method. Therefore, utilizing this feature, it is expected to be used as an ion implantation shielding mask in the ion implantation process which is a part of the three-dimensional transistor formation process. However, in the organic resist underlayer film pattern for ion implantation formed by the three-layer resist method, the substrate is not processed using the organic resist underlayer film pattern as a mask. Silicon remains on the pattern. Therefore, when ions are implanted using such an organic resist underlayer film pattern as a shielding mask, the silicon remaining on the organic resist underlayer film is modified by the implanted ions, and the organic resist is removed in the cleaning process after the implanting process. Those that cannot be removed at the same time as the underlying film pattern will eventually remain on the substrate as foreign matter, resulting in a decrease in the yield of the ion implantation process. In order to prevent this, the silicon remaining on the organic resist underlayer film pattern must be selectively washed away without affecting the organic resist underlayer film pattern before ion implantation. However, this silicon content is denatured by the dry etching gas when transferring the pattern to the organic resist underlayer film, and hydrogen peroxide-containing ammonia aqueous solution, which is generally applied in the semiconductor manufacturing process as a cleaning solution that does not damage the substrate, is used. (hereinafter also referred to as ammonia hydrogen peroxide solution) cannot be washed away. In order to completely remove the modified silicon content by washing, it is necessary to apply a hydrofluoric acid-based cleaning solution, but this cleaning solution also damages the surface of the semiconductor substrate, resulting in a decrease in yield in the processing step. Therefore, there is a demand for a method and a suitable material for removing the silicon portion remaining on the organic resist underlayer film pattern without damaging the substrate after pattern transfer to the organic resist underlayer film by dry etching is completed. .

Japanese Patent Application Laid-Open No. 2016-094612 (US Patent Application Publication No. 2013/0337649 (A1))

The present invention has been made in view of the above problems, and is a stripping solution that does not damage semiconductor device substrates and organic resist underlayer films required in the patterning process. Using a hydrogen peroxide-containing aqueous ammonia solution called SC1 (Standard Cleaner 1), a substrate with a resist multilayer film that can easily wet-remove silicon residue denatured by dry etching, and a substrate with the resist multilayer film. An object of the present invention is to provide a pattern formation method.

In order to solve the above problems, the present invention provides a substrate with a resist multilayer film having a substrate and a resist multilayer film formed on the substrate, wherein the resist multilayer film is coated with ammonia hydrogen peroxide from the substrate side. Provided is a substrate with a resist multilayer film having, in this order, an organic resist underlayer film sparingly soluble in water, an organic film soluble in ammonia hydrogen peroxide, a silicon-containing resist intermediate film, and a resist overlayer film.

If it is a substrate with such a resist multilayer film, it is a stripping solution that does not damage the semiconductor device substrate or the organic resist underlayer film required in the patterning process, such as SC1, which is commonly used in the semiconductor manufacturing process. Ammonia hydrogen peroxide solution can be used to easily wet-remove the silicon residue denatured by dry etching.

（式中、Ｒ_１は炭素数１～１９の炭化水素基、ハロゲン原子、アルコキシ基、カルボキシ基、スルホ基、メトキシカルボニル基、ヒドロキシフェニル基、又はアミノ基であり、Ｒ_２は水素原子又はＡＬである。ＡＬは加熱又は酸の作用により酸性の官能基を生じる基である。Ｒ_３は水素原子、フラニル基、又は塩素原子もしくはニトロ基を有していてもよい炭素数１～１６の炭化水素基である。ｋ_１、ｋ_２、及びｋ_３は１～２であり、ｌは１～３であり、ｍは０～３であり、ｎは０又は１である。） At this time, the organic film soluble in ammonia hydrogen peroxide mixture contains a polymer compound having one or more repeating units represented by the following general formulas (1) to (4) and an organic solvent. It is preferably a cured product of a composition for use.

(In the formula, R ₁ is a hydrocarbon group having 1 to 19 carbon atoms, a halogen atom, an alkoxy group, a carboxy group, a sulfo group, a methoxycarbonyl group, a hydroxyphenyl group, or an amino group, and R ₂ is a hydrogen atom or AL AL is a group that generates an acidic functional group by the action of heat or acid, and R ₃ is a hydrogen atom, a furanyl group, or a carbonized group having 1 to 16 carbon atoms which may have a chlorine atom or a nitro group. a hydrogen group, k ₁ , k ₂ and k ₃ are 1 to 2, l is 1 to 3, m is 0 to 3, and n is 0 or 1.)

If it is an organic film soluble in such ammonia peroxide water (hereinafter simply referred to as an organic film), a stripping solution that does not damage the semiconductor device substrate or the organic resist underlayer film required in the patterning process, such as a semiconductor Ammonia peroxide treatment, called SC1, commonly used in the manufacturing process, makes it readily wet removable along with dry-etch modified silicon residue. When a substrate with a resist multilayer film having such an organic film is used for pattern formation, an organic resist underlayer film pattern free of silicon residue can be obtained. Substrate processing of transistors can be performed with a high yield.

Moreover, at this time, in the organic solvent, the total amount of one or more selected from propylene glycol esters, ketones, and lactones preferably accounts for more than 30 wt % of the total organic solvent.

If the composition for forming an organic film containing an organic solvent that satisfies these conditions is used, the coatability of the organic film on the organic resist underlayer film is ensured, and the resulting organic film on the substrate with the resist multilayer film is defect-free and homogeneous. become something.

In this case, the composition for forming an organic film preferably further contains either or both of a thermal acid generator and a cross-linking agent.

If the composition for forming an organic film contains either or both of a thermal acid generator and a cross-linking agent, the obtained substrate with a resist multilayer film has an organic film of uniform thickness on the organic resist underlayer film. Not only can the composition be uniform, but intermixing can be suppressed when laminating a silicon-containing resist intermediate film on an organic film.

Further, at this time, the organic film soluble in the ammonia hydrogen peroxide solution is treated with a solution of 29% ammonia water/35% hydrogen peroxide water/water=1/1/8 at 65° C., and is processed at 5 nm/min or more. preferably have a dissolution rate of

In the case of a substrate with a resist multilayer film containing an organic film having such performance, the organic film and silicon residue on the organic film are sufficiently removed with ammonia hydrogen peroxide mixture without damaging the substrate for semiconductor device manufacturing. be able to.

Furthermore, it is preferable that the thickness of the organic film soluble in ammonia hydrogen peroxide is 10 nm or more and less than 100 nm.

In the substrate with a resist multilayer film of the present invention, if the film thickness of the organic film is within this range, the silicon residue can be sufficiently removed, and the silicon-containing resist intermediate film can be used as a dry etching mask to etch the organic film and the organic film at once. Even if the pattern is transferred to the resist lower layer film, it is possible to transfer the pattern while maintaining the accuracy of the pattern formed by the resist upper layer film.

Moreover, the silicon-containing resist intermediate film preferably contains either or both of boron and phosphorus.

Using the patterned silicon-containing resist intermediate film as a mask, when the pattern is transferred to the organic film and the organic resist underlayer film at once by dry etching, the silicon-containing resist intermediate film pattern undergoes a structural change due to the action of gas and plasma during dry etching. However, the solubility in ammonia peroxide water may decrease. However, since the silicon-containing resist intermediate film contains one or both of boron and phosphorus, the silicon-containing resist intermediate film and/or is soluble in ammonia hydrogen peroxide even after dry etching, regardless of the dry etching gas and conditions. Alternatively, it can be a silicon residue.

Further, in the present invention, the resist upper layer film of the above substrate with a resist multilayer film is exposed, developed with a developer to form a pattern in the resist upper layer film, and the resist upper layer film having the pattern formed thereon is used as an etching mask. etching the silicon-containing resist intermediate film to form a pattern; using the patterned silicon-containing resist intermediate film as an etching mask, etching the organic film and the organic resist underlayer film to form a pattern; The patterned silicon-containing resist intermediate film and the patterned organic film are removed by treatment with ammonia hydrogen peroxide mixture, and the patterned organic resist underlayer film is used as a mask to form a pattern on the substrate. A patterning method is provided.

With such a pattern formation method, a stripping solution that does not damage the semiconductor device substrate or the organic resist underlayer film required in the patterning process, such as an ammonia peroxide called SC1 commonly used in the semiconductor manufacturing process, is used. Since the silicon residue denatured by dry etching can be easily wet-removed using water, it is possible to form an organic resist underlayer film pattern in which no silicon remains on the pattern.

Furthermore, after forming the pattern on the substrate, the organic resist underlayer film having the pattern formed thereon is preferably removed by dry etching or wet etching.

In the pattern forming method of the present invention, an organic film soluble in ammonia hydrogen peroxide mixture is formed between an organic resist underlayer film and a silicon-containing resist intermediate film formed immediately below the photoresist in a three-layer resist method formed on a substrate. This is a method using the substrate with the introduced resist multilayer film, and is substantially a four-layer resist method. An organic resist underlayer film is formed on a substrate, an organic film soluble in ammonia peroxide is formed on the organic resist underlayer film (that is, between the organic resist underlayer film and the silicon-containing resist intermediate film), and then silicon After forming a containing resist intermediate film and further forming a resist upper layer film, a pattern is formed in the resist upper layer film, this pattern is transferred to the silicon-containing resist intermediate film by dry etching, and the transferred pattern is used as a mask, The pattern is transferred by dry etching the organic film and the organic resist underlayer film at once. Here, if the silicon-containing resist intermediate film is soluble in ammonia hydrogen peroxide water and the organic resist underlayer film is sparingly soluble in ammonia hydrogen peroxide water, then the organic resist underlayer film pattern is treated with ammonia hydrogen peroxide water. The remaining silicon portion is removed together with the organic film, and as a result, an organic resist underlayer film pattern free of silicon portion residue can be formed. When the organic resist underlayer film pattern obtained in this way is applied as a mask when forming a pattern on a substrate, when the organic resist underlayer film pattern is finally removed by dry etching or wet etching, no foreign matter remains on the substrate, and a step is formed. Even in the case of forming a three-dimensional transistor with a large value, the substrate can be processed with a high yield.

If it is a substrate with a resist multilayer film of the present invention, a stripping solution that does not damage the semiconductor device substrate or the organic resist underlayer film required in the patterning process, such as SC1, which is commonly used in the semiconductor manufacturing process. Ammonia hydrogen peroxide can be used to remove wet-removable organic films as well as denatured silicon residues by dry etching. As a result, an organic resist underlayer film pattern in which no silicon content remains on the pattern can be formed, and the substrate can be processed using this as a mask to form a pattern. After such an organic resist underlayer film pattern is removed by dry etching or wet etching, no foreign matter remains on the substrate, so that it is possible to prevent a decrease in yield in the manufacturing process of the three-dimensional transistor. That is, it becomes possible to economically manufacture a semiconductor device with higher performance.
In the pattern forming method of the present invention, a stripping solution that does not damage the semiconductor device substrate and the organic resist underlayer film required in the patterning process, for example, SC1, which is commonly used in the semiconductor manufacturing process, is used. Since the silicon residue denatured by dry etching can be easily removed by a wet method using ammonia hydrogen peroxide, an organic resist underlayer film pattern in which no silicon remains on the pattern can be formed.

As described above, a stripping solution that does not damage the semiconductor device substrate and the organic resist underlayer film required in the patterning process, for example, an ammonia hydrogen peroxide solution called SC1 commonly used in the semiconductor manufacturing process, is used for drying. There has been a demand for a substrate with a resist multilayer film and a pattern forming method capable of removing silicon residue modified by etching and suppressing foreign matter from remaining on the substrate after processing.

As a result of intensive studies on the above problems, the present inventors have found a substrate with a resist multilayer film having a substrate and a resist multilayer film formed on the substrate, wherein the resist multilayer film is exposed to ammonia from the substrate side. A substrate with a resist multilayer film having, in this order, an organic resist lower layer film sparingly soluble in hydrogen peroxide, an organic film soluble in ammonia hydrogen peroxide, an intermediate resist film containing silicon, and a resist upper layer film solves the above problems. We have found that the problem can be solved, and completed the present invention.

Embodiments of the present invention will be described below, but the present invention is not limited to these.

[Substrate with resist multilayer film]
A substrate with a resist multilayer film of the present invention comprises a substrate and a resist multilayer film (laminated film) formed on the substrate.

[substrate]
The substrate (substrate to be processed) in the substrate with a resist multilayer film of the present invention is not particularly limited, and includes semiconductor substrates such as silicon substrates, insulating substrates such as glass substrates, metal substrates, resin substrates, and the like. However, TiN, W, SiO ₂ , SiN, p-Si, Al, silica-based low dielectric constant insulating films, and the like can be preferably used as the layer to be processed, particularly on the surface.

[Resist multilayer film]
The resist multilayer film in the substrate with a resist multilayer film of the present invention comprises, from the substrate side, an organic resist underlayer film sparingly soluble in ammonia hydrogen peroxide water, an organic film soluble in ammonia hydrogen peroxide water, a silicon-containing resist intermediate film, a resist and an upper layer film in this order. Each film will be described in detail below.

<Organic resist underlayer film>
The resist multilayer film in the substrate with the resist multilayer film of the present invention has an organic resist underlayer film. This organic resist underlayer film is resistant to ammonia hydrogen peroxide mixture (that is, poorly soluble in ammonia hydrogen peroxide mixture). Here, the organic resist underlayer film that is sparingly soluble in ammonia peroxide water is specifically treated with a solution of 29% ammonia water/35% hydrogen peroxide water/water=1/1/8 mixed at 65°C. , refers to those having a dissolution rate of 3 nm/min or less.

Examples of such an organic resist underlayer film include, for example, JP-A-2004-205685 (US Pat. No. 7,427,464 (B2)), JP-A-2010-122656 (US Pat. /0099044 (A1) and US Patent Application Publication No. 2013/0184404 (A1)), JP 2012-214720 (US Patent Application Publication No. 2012/0252218 (A1)), An organic resist underlayer film disclosed in JP-A-2016-094612 (US Patent Application Publication No. 2013/0337649 (A1)) can be used.

The above organic resist underlayer film is formed by coating a substrate to be processed with a composition for forming an organic resist underlayer film by spin coating or the like. Good embedding characteristics can be obtained by using a spin coating method or the like. After spin coating, the solvent is evaporated, and baking is performed to prevent mixing with the resist upper layer film or the silicon-containing resist intermediate film, or to promote the cross-linking reaction. Baking is performed at a temperature of 100° C. to 600° C. for 10 to 600 seconds, preferably 10 to 300 seconds. The baking temperature is more preferably 200° C. or higher and 500° C. or lower. Considering the effects on device damage and wafer deformation, the upper limit of the heating temperature in the wafer process of lithography is preferably 600° C. or less, more preferably 500° C. or less.

In the method of forming the organic resist underlayer film as described above, the composition for forming the organic resist underlayer film is coated on the substrate to be processed by a spin coating method or the like, and the composition is applied to air, N ₂ , Ar, or He. The organic resist underlayer film can be formed by baking and curing in such an atmosphere. By baking this composition for forming an organic resist underlayer film in an oxygen-containing atmosphere, a cured film that is resistant to ammonia hydrogen peroxide can be obtained.

By forming the organic resist underlayer film in this way, it is possible to obtain a flat cured film regardless of the unevenness of the substrate to be processed due to its excellent embedding/flattening characteristics. Alternatively, it is extremely useful when forming a flat cured film on a substrate having steps.

The thickness of the organic resist underlayer film for semiconductor device manufacturing and planarization is appropriately selected, but is preferably 5 to 500 nm, particularly 10 to 400 nm.

（式中、Ｒ_１は炭素数１～１９の炭化水素基、ハロゲン原子、アルコキシ基、カルボキシ基、スルホ基、メトキシカルボニル基、ヒドロキシフェニル基、又はアミノ基であり、Ｒ_２は水素原子又はＡＬである。ＡＬは加熱又は酸の作用により酸性の官能基を生じる基である。Ｒ_３は水素原子、フラニル基、又は塩素原子もしくはニトロ基を有していてもよい炭素数１～１６の炭化水素基である。ｋ_１、ｋ_２、及びｋ_３は１～２であり、ｌは１～３であり、ｍは０～３であり、ｎは０又は１である。） <Organic film soluble in ammonia hydrogen peroxide solution>
The resist multilayer film in the substrate with a resist multilayer film of the present invention has an organic film soluble in ammonia hydrogen peroxide mixture. As the organic film soluble in ammonia peroxide water, an organic film-forming composition containing a polymer compound having at least one repeating unit represented by any one of the following general formulas (1) to (4) and an organic solvent (that is, a cured product of the composition for forming an organic film).

(In the formula, R ₁ is a hydrocarbon group having 1 to 19 carbon atoms, a halogen atom, an alkoxy group, a carboxy group, a sulfo group, a methoxycarbonyl group, a hydroxyphenyl group, or an amino group, and R ₂ is a hydrogen atom or AL AL is a group that generates an acidic functional group by the action of heat or acid, and R ₃ is a hydrogen atom, a furanyl group, or a carbonized group having 1 to 16 carbon atoms which may have a chlorine atom or a nitro group. a hydrogen group, k ₁ , k ₂ and k ₃ are 1 to 2, l is 1 to 3, m is 0 to 3, and n is 0 or 1.)

Here, as the repeating unit represented by the general formula (1), those having the following structures can be exemplified.

Examples of repeating units represented by formula (2) include those having the following structures.

Examples of repeating units represented by formula (3) include those having the following structures.

As the repeating unit represented by formula (4), the following structures can be exemplified.

Among these, preferred repeating units are those represented by the above general formula (2) or (3). An organic film-forming composition containing a polymer compound having such a repeating unit forms an organic film excellent in wet removability with ammonia water mixture because the highly polar carboxyl group is effectively positioned. can.

Here, as the repeating units represented by the above general formulas (1) to (4), the monomers for obtaining n=0 include phenol, o-cresol, m-cresol, p-cresol, 2,3 -dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 3, 4,5-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-t-butylcatechol , 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5-methylphenol, 4-phenylphenol, tritylphenol, pyrogallol, thymol, hydroxyphenyl glycidyl ether, 4-fluorophenol, 3,4-difluorophenol, 4-trifluoromethylphenol, 4-chloro Phenol, 4-hydroxybenzenesulfonic acid, 4-vinylphenol, 1-(4-hydroxyphenyl)naphthalene and the like can be mentioned.

Monomers for obtaining n=1 include 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, 1,2-dihydroxy Naphthalene, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene , 2,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 5-amino-1-naphthol, 2-methoxycarbonyl-1-naphthol, 6-(4-hydroxyphenyl)-2-naphthol, 6-(cyclohexyl) -2-naphthol, 1,1'-bi-2,2'-naphthol, 6,6'-bi-2,2'-naphthol, 9,9-bis(6-hydroxy-2-naphthyl)fluorene, 6 -hydroxy-2-vinylnaphthalene, 1-hydroxymethylnaphthalene, 2-hydroxymethylnaphthalene, 8-hydroxynaphthalene-1-sulfonic acid, 2-hydroxynaphthalene-7-sulfonic acid, 2,3-dihydroxynaphthalene-7-sulfone acid, 1,7-dihydroxynaphthalene-3-sulfonic acid, and the like.

Each of these may be used alone, or two or more of them may be used in combination to control the n value, k value, and etching resistance.

Examples of condensing agents for condensation reaction with these monomers include the following aldehyde compounds. For example, formaldehyde, trioxane, paraformaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, cyclopentanecarboxaldehyde, cyclopentenecarboxaldehyde, cyclohexanecarboxaldehyde, cyclohexenecarboxaldehyde, norbornanecarboxaldehyde, norbornenecarboxaldehyde, adamantanecarbaldehyde, benzaldehyde, phenylacetaldehyde , α-phenylpropylaldehyde, β-phenylpropylaldehyde, 2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, 2 - chlorobenzaldehyde, 3-chlorobenzaldehyde, 4-chlorobenzaldehyde, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, 2-ethylbenzaldehyde, 3 -ethylbenzaldehyde, 4-ethylbenzaldehyde, 2-methoxybenzaldehyde, 3-methoxybenzaldehyde, 4-methoxybenzaldehyde, anthracenecarbaldehyde, pyrenecarbaldehyde, furfural and the like.

In addition, compounds represented by the following formulas can be exemplified.

The ratio of the monomer and the aldehyde compound as the condensing agent is preferably 0.01 to 5 mol, more preferably 0.05 to 2 mol, per 1 mol of the total molar amount of the monomers.

The ratio of the repeating units represented by the general formulas (1) to (4) to all repeating units is preferably 10% or more, more preferably 30% or more, based on 100% of the whole.

When the polycondensation reaction is carried out using the raw materials as described above, it is usually carried out in the absence of solvent or in a solvent using an acid or base as a catalyst at room temperature or under cooling or heating as necessary. Thereby, a high molecular compound (polymer) can be obtained. Solvents used include alcohols such as methanol, ethanol, isopropyl alcohol, butanol, ethylene glycol, propylene glycol, diethylene glycol, glycerol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, diethyl ether, dibutyl ether, and diethylene glycol diethyl. Ethers such as ether, diethylene glycol dimethyl ether, tetrahydrofuran, and 1,4-dioxane; chlorinated solvents such as methylene chloride, chloroform, dichloroethane, and trichlorethylene; hydrocarbons such as hexane, heptane, benzene, toluene, xylene, and cumene; and acetonitrile. nitriles such as acetone, ethyl methyl ketone, isobutyl methyl ketone and the like, esters such as ethyl acetate, n-butyl acetate and propylene glycol methyl ether acetate, lactones such as γ-butyrolactone, dimethyl sulfoxide, N, Aprotic polar solvents such as N-dimethylformamide and hexamethylphosphoric triamide can be exemplified, and these can be used alone or in combination of two or more. These solvents can be used in the range of 0 to 2,000 parts by mass per 100 parts by mass of the reaction raw material.

Acid catalysts include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, inorganic acids such as heteropoly acids, oxalic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfone. Organic acids such as acids, aluminum trichloride, aluminum ethoxide, aluminum isopropoxide, boron trifluoride, boron trichloride, boron tribromide, tin tetrachloride, tin tetrabromide, dibutyltin dichloride, dibutyltin dimethoxide , dibutyltin oxide, titanium tetrachloride, titanium tetrabromide, titanium (IV) methoxide, titanium (IV) ethoxide, titanium (IV) isopropoxide, and titanium (IV) oxide. Examples of basic catalysts include inorganic bases such as sodium hydroxide, potassium hydroxide, barium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, lithium hydride, sodium hydride, potassium hydride, calcium hydride, and methyllithium. , n-butyllithium, methylmagnesium chloride, alkyl metals such as ethylmagnesium bromide, alkoxides such as sodium methoxide, sodium ethoxide, potassium t-butoxide, triethylamine, diisopropylethylamine, N,N-dimethylaniline, pyridine , 4-dimethylaminopyridine and the like can be used. The amount used is preferably 0.001 to 100% by weight, more preferably 0.005 to 50% by weight, based on the starting material. The reaction temperature is preferably from -50°C to about the boiling point of the solvent, more preferably from room temperature to 100°C.

Examples of the polycondensation reaction method include a method of charging the monomer, the condensing agent and the catalyst all at once, and a method of dropping the monomer and the condensing agent in the presence of the catalyst.

In addition, after the polycondensation reaction is completed, in order to remove unreacted raw materials, catalysts, etc. present in the system, the temperature of the reactor is raised to 130 to 230° C., and volatile matter is removed at about 1 to 50 mmHg. , a method of adding an appropriate solvent or water to fractionate the polymer, a method of dissolving the polymer in a good solvent and then reprecipitating it in a poor solvent, etc. can be used depending on the properties of the obtained reaction product.

The weight-average molecular weight (Mw) of the polymer thus obtained in terms of polystyrene is preferably 500 to 500,000, more preferably 1,000 to 100,000. Also, the molecular weight dispersity is preferably in the range of 1.2 to 20. Volatile components during baking can be suppressed by removing monomer components, oligomer components, or low molecular weight substances with a molecular weight (Mw) of 1,000 or less. It is possible to prevent surface defects caused by

An organic film-forming composition suitable for forming an organic film soluble in ammonia peroxide contains an organic solvent. Specific examples of organic solvents include ketones such as cyclopentanone, cyclohexanone, methyl-2-amyl ketone, 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy- 2-propanol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether and other alcohols, propylene glycol dimethyl ether, diethylene glycol dimethyl ether and other ethers, propylene glycol monomethyl ether acetate, propylene glycol mono Esters such as ethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono tert-butyl ether acetate .

Here, among the above organic solvents, one or more selected from propylene glycol esters, ketones, and lactones (for example, among the organic solvents exemplified above, propylene glycol monomethyl ether acetate, cyclopentanone, cyclohexanone, methyl-2-amyl ketone, , γ-butyrolactone) accounts for more than 30% by weight in the total amount of the organic solvent. When the organic solvent satisfies this condition, a uniform organic film can be reliably formed directly on the organic resist underlayer film.

In addition, an acid generator and a cross-linking agent can be added to the organic film-forming composition to further promote the cross-linking reaction. As the acid generator, there are those that generate acid by thermal decomposition (thermal acid generators) and those that generate acid by light irradiation, and any of them can be added.

Acid generators include onium salts, diazomethane derivatives, glyoxime derivatives, bissulfone derivatives, sulfonic acid esters of N-hydroxyimide compounds, β-ketosulfonic acid derivatives, disulfone derivatives, nitrobenzylsulfonate derivatives, sulfonates, and sulfonate ester derivatives. etc. can be mentioned. Specifically, those described in paragraphs (0081) to (0111) of JP-A-2008-65303 (US Patent Application Publication No. 2008/0038662 (A1)) can be mentioned.

Examples of cross-linking agents include melamine compounds, guanamine compounds, glycoluril compounds or urea compounds substituted with at least one group selected from methylol groups, alkoxymethyl groups and acyloxymethyl groups, epoxy compounds, thioepoxy compounds, isocyanate compounds, azides. compounds, compounds containing double bonds such as alkenyl ether groups, and the like. Specifically, those described in paragraphs (0074) to (0080) of JP-A-2008-65303 (US Patent Application Publication No. 2008/0038662 (A1)) can be mentioned.

A surfactant may also be added to the above organic film-forming composition in order to improve coatability in spin coating. Surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid ester nonionic surfactants, fluorine surfactants, partially fluorinated oxetane ring-opening polymer-based surfactants, and the like. Specifically, those described in paragraphs (0142) to (0147) of JP-A-2009-269953 (US Patent Application Publication No. 2009/0274978 (A1)) can be mentioned.

Furthermore, a basic compound can be added to the above composition for forming an organic film to improve storage stability. The basic compound plays a role of a quencher for the acid to prevent the progress of the cross-linking reaction of the acid generated in a trace amount by the acid generator. Such basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, sulfonyl groups, , nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amide derivatives, imide derivatives, and the like. Specifically, those described in paragraphs (0112) to (0119) of JP-A-2008-65303 (US Patent Application Publication No. 2008/0038662 (A1)) can be mentioned.

The composition for forming an organic film described above forms an organic film soluble in ammonia hydrogen peroxide water, which is introduced directly below the silicon-containing resist intermediate film and directly above the organic resist underlayer film that is sparingly soluble in ammonia hydrogen peroxide water. It can be suitably used for

In order to wet-remove the silicon residues modified by dry etching together, the above organic film was treated with a solution mixed with 29% ammonia water/35% hydrogen peroxide water/water=1/1/8 at 65°C. It preferably has a dissolution rate of 5 nm/min or more at .

The thickness of the organic film is preferably 10 nm or more and less than 100 nm, and more preferably 20 nm or more and 80 nm or less. If the film thickness of the organic film is 10 nm or more, a sufficient effect of removing the silicon content by the wet treatment can be obtained. .

Examples of the method of forming the above organic film include a method of coating a substrate to be processed with a composition for forming an organic film by a spin coating method or the like. After spin coating, the solvent is evaporated, and baking is performed to prevent mixing with the resist upper layer film or the silicon-containing resist intermediate film, or to promote the cross-linking reaction. Baking is performed at a temperature of 100° C. to 400° C. for 10 to 600 seconds, preferably 10 to 300 seconds. The baking temperature is more preferably 150° C. or higher and 350° C. or lower.

<Silicon-containing resist intermediate film>
The resist multilayer film in the substrate with a resist multilayer film of the present invention has a silicon-containing resist intermediate film. As such a silicon-containing resist intermediate film, one that is soluble in ammonia hydrogen peroxide mixture and can be dissolved or peeled off with ammonia hydrogen peroxide mixture is preferable. For example, JP 2010-085912 (US Patent Application Publication No. 2010/0086870 (A1)), JP 2010-085893 (US Patent Application Publication No. 2010/0086872 (A1)), JP 2015-028145 (US Patent Application Publication No. 2015/0004791 (A1)), WO 2010/068336 (US Patent Application Publication No. 2011/0233489 (A1)), JP 2016-074772 (US Patent Application Publication No. 2016/0096977 (A1)), JP 2016-074774 (US Patent Application Publication No. 2016/0096978 (A1)) Silicon-containing described It is preferable to use the resist underlayer film as the silicon-containing resist intermediate film in the present invention. Among these, those containing either or both of boron and phosphorus are particularly preferable because they are excellent in wet removability with ammonia hydrogen peroxide mixture.

<Resist upper layer film>
The resist multilayer film in the substrate with the resist multilayer film of the present invention has a resist upper layer film. The resist upper layer film is not particularly limited, and can be appropriately selected according to the pattern forming method. For example, when performing lithography using light with a wavelength of 300 nm or less or EUV light, a chemically amplified photoresist film, for example, can be used as the resist upper layer film. As such a photoresist film, there are those that form a positive pattern by dissolving the exposed areas with an alkaline developer after exposure, and those that dissolve the unexposed areas with a developer made of an organic solvent. An example of forming a negative pattern can be exemplified by

When lithography is performed using ArF excimer laser light as light having a wavelength of 300 nm or less, any ordinary resist film for ArF excimer laser light can be used as the resist upper layer film. A large number of candidates for the composition that provides such a resist film for ArF excimer laser light are already known, and can be broadly classified into poly(meth)acrylic, COMA (Cyclo Olefin Maleic Anhydride), and COMA-(meth)acrylic. There are hybrid systems, ROMP (Ring Opening Metathesis Polymerization) systems, polynorbornene systems, and the like. Since the durability is ensured, the resolution performance is superior to that of other resin systems and can be preferably used.

The resist upper layer film can be formed by a spin coating method or the like. The thickness of the resist upper layer film is appropriately selected, but preferably 20 to 500 nm, particularly 30 to 400 nm.

For a substrate with a resist multilayer film as described above, a stripping solution that does not damage the semiconductor device substrate and the organic resist underlayer film required in the patterning process, such as SC1, which is commonly used in the semiconductor manufacturing process, is used. Ammonia hydrogen peroxide called "Ammonia Peroxide" can be used to easily wet-remove the silicon residue that has been denatured by dry etching together with the organic film. In addition, when the pattern of the obtained organic resist underlayer film is removed by dry etching or wet etching after processing the substrate, it is possible to prevent foreign matter from remaining on the substrate. As a result, it becomes possible to prevent a decrease in yield in the manufacturing process of the three-dimensional transistor, and it becomes possible to economically manufacture high-performance semiconductor devices.

(Pattern formation method)
The present invention provides a pattern forming method using the substrate with the resist multilayer film described above. In the pattern forming method of the present invention, the resist upper layer film of the substrate with the above resist multilayer film is exposed, developed with a developer to form a pattern in the resist upper layer film, and the patterned resist upper layer film is used as an etching mask. Etching the silicon-containing resist intermediate film to form a pattern, using the patterned silicon-containing resist intermediate film as an etching mask, etching the organic film and the organic resist underlayer film to form a pattern, and forming the pattern. The silicon-containing resist intermediate film and the patterned organic film are removed by treatment with ammonia hydrogen peroxide mixture, and the patterned organic resist underlayer film is used as a mask to form a pattern on the substrate.

Furthermore, after forming the pattern on the substrate, the substrate processing is preferably completed by removing the patterned organic resist underlayer film by dry etching or wet etching.

In the pattern forming method of the present invention, first, the resist upper layer film of the substrate with the resist multilayer film of the present invention is exposed and developed with a developer to form a pattern on the resist upper layer film. As described above, the resist upper layer film may be of either a positive type or a negative type, and the same photoresist composition as commonly used can be used. When forming a resist upper layer film using a photoresist composition, a spin coating method is preferably used.

When the photoresist composition is pre-baked after spin coating, the temperature is preferably 60 to 180° C. for 10 to 300 seconds. After that, exposure, post-exposure baking (PEB), and development are carried out according to a conventional method to obtain a resist pattern. Although the thickness of the resist upper layer film is not particularly limited, it is preferably 20 to 500 nm, particularly 30 to 400 nm. Examples of exposure light include high-energy rays with a wavelength of 300 nm or less, specifically excimer lasers of 248 nm and 193 nm, extreme ultraviolet rays of 13.5 nm, electron beams, and X-rays.

Next, using the obtained resist upper layer film pattern as an etching mask, the silicon-containing resist intermediate film is dry-etched to form a pattern. Dry etching at this time is not particularly limited, but it is preferable to use a CF-based gas such as CF ₄ or CHF ₃ .

Next, using the silicon-containing resist intermediate film pattern as an etching mask, the organic film soluble in ammonia hydrogen peroxide mixture and the organic resist underlayer film are etched at once to form a pattern. Dry etching at this time is not particularly limited, but it is preferable to use, for example, N ₂ /H ₂ gas or O ₂ gas.

Furthermore, the remaining silicon-containing resist intermediate film pattern and the organic film pattern are wet-removed together. Here, it is preferable to use a stripping solution containing hydrogen peroxide. Further, it is more preferable to adjust the pH by adding an acid or an alkali to the stripping solution in order to promote stripping. Examples of such pH adjusters (acids or alkalis) include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as acetic acid, oxalic acid, tartaric acid, citric acid and lactic acid, ammonia, ethanolamine, tetramethylammonium hydroxide and the like. Nitrogen-containing alkalis and nitrogen-containing organic acid compounds such as EDTA (ethylenediaminetetraacetic acid) can be exemplified. Ammonia is particularly preferred. That is, ammonia hydrogen peroxide mixture is preferable as the stripping solution.

When ammonia hydrogen peroxide is used as the stripping solution, the ratio of ammonia to hydrogen peroxide to deionized water for dilution is 0.01 to 20 parts by mass, preferably 0.01 to 20 parts by mass of ammonia per 100 parts by mass of deionized water. 05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, hydrogen peroxide is 0.01 to 20 parts by mass, preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass Department.

Ammonia hydrogen peroxide treatment can be carried out simply by preparing a stripping solution at 0° C. to 80° C., preferably 5° C. to 70° C., and immersing the silicon wafer on which the substrate to be processed is formed. Furthermore, if necessary, the silicon-containing resist intermediate film and the ammonia-hydrogen-soluble organic solvent can be easily removed by standard procedures, such as spraying the stripping solution on the surface or applying the stripping solution while rotating the wafer. The film can be removed all at once.

After the ammonia hydrogen peroxide treatment, it is preferable to quantify the amount of silicon remaining on the surface of the organic resist underlayer film to confirm the degree of silicon removal. For example, analysis can be performed by the method described in Japanese Patent Application Laid-Open No. 2016-177262 (US Patent Application Publication No. 2016/0276152 (A1)).

Using the pattern of the organic resist underlayer film thus obtained as a mask, a pattern is formed on the substrate (substrate processing). The pattern forming method of the present invention can be suitably used in substrate processing that does not use dry etching, such as various ion implantation processing and substrate processing by wet etching. If the substrate to be processed is made of TiN or W, which can be etched with ammonia hydrogen peroxide mixture, the substrate can be processed at the same time that the silicon residue and the organic film are removed with ammonia hydrogen peroxide mixture. _In addition, substrate processing by dry etching is also possible. A condition mainly based on a system and a bromine-based gas is used.

After finishing the substrate processing, the organic resist underlayer film pattern used as a mask is removed by dry etching or wet etching. Conditions for dry etching (ashing) are not particularly limited, but it is preferable to use, for example, N ₂ /H ₂ gas or O ₂ gas as in the processing of the organic resist underlayer film. The wet etching conditions are also not particularly limited, but a wet treatment using sulfuric acid peroxide can be exemplified. By using the pattern forming method of the present invention, it is possible to prevent foreign matter from remaining on the substrate after removing the organic resist underlayer film pattern.

As described above, in the pattern forming method of the present invention, an organic resist underlayer film is formed on a substrate, an organic film soluble in ammonia hydrogen peroxide is formed on the organic resist underlayer film, and then a silicon-containing resist intermediate layer is formed on the organic resist underlayer film. After forming a film and further forming a resist upper layer film to obtain a substrate with a resist multilayer film, a pattern is formed in the resist upper layer film, this pattern is transferred to the silicon-containing resist intermediate film by dry etching, and the transferred By using this pattern as a mask, the organic film and the organic resist underlayer film can be dry-etched at once to transfer the pattern. As described above, silicon remaining on the transferred pattern can be removed together with the organic film with ammonia hydrogen peroxide mixture, and an organic resist underlayer film pattern free of silicon residue can be obtained. This organic resist underlayer film pattern can be used as a mask for substrate processing, and can prevent foreign matter from remaining on the substrate when finally removed by dry etching or wet etching. As a result, substrate processing can be performed with a high yield even when a three-dimensional transistor having a large step is formed.

EXAMPLES The present invention will be specifically described below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited by these descriptions. In the following examples, % indicates % by mass, and the molecular weight was measured by GPC. In the GPC measurement, RI was used for detection, and tetrahydrofuran was used as the elution solvent to determine the molecular weight in terms of polystyrene.

[Synthesis of polymer compound]
[Synthesis Example (A1)]
40.00 g (0.36 mol) of resorcinol, 10.00 g of a 20% by mass PGME solution of p-toluenesulfonic acid monohydrate, and 72.00 g of 2-methoxy-1-propanol were placed in a 500 ml three-necked flask and stirred. while heating to 80°C. 23.59 g of 37% formalin (0.29 mol of formaldehyde) was added thereto and stirred for 11 hours. 160 g of ultrapure water and 200 g of ethyl acetate were added to the reaction solution, transferred to a separating funnel, and washed 10 times with 150 g of ultrapure water to remove the acid catalyst and metal impurities. The obtained organic layer was concentrated under reduced pressure to 76 g, ethyl acetate was added to make a 150 g solution, and 217 g of n-hexane was added. The n-hexane layer was the upper layer and the high-concentration polymer solution was the lower layer, and the upper layer was removed. The same operation was repeated twice, and the resulting polymer solution was concentrated and dried under reduced pressure at 80° C. for 13 hours to obtain polymer compound A1. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were obtained by GPC, they were found to be Mw=800 and Mw/Mn=1.3. This polymer compound A1 has a repeating unit represented by the general formula (4).

[Synthesis example (A2)]
80.1 g (0.50 mol) of 1,5-dihydroxynaphthalene, 26.4 g (0.24 mol) of 37% formalin solution, and 250 g of 2-methoxy-1-propanol were placed in a 1,000 ml three-necked flask under a nitrogen atmosphere. After making a uniform solution at a liquid temperature of 80°C, 18 g of a 20% p-toluenesulfonic acid 2-methoxy-1-propanol solution was slowly added, and the mixture was stirred at a liquid temperature of 110°C for 12 hours. After cooling to room temperature, 500 g of methyl isobutyl ketone was added, the organic layer was washed with 200 g of pure water five times, and the organic layer was dried under reduced pressure. 300 mL of THF was added to the residue, and the polymer was reprecipitated with 2,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A2. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=3,000 and Mw/Mn=2.7. This polymer compound A2 has a repeating unit represented by the general formula (4).

[Synthesis example (A3)]
80.1 g (0.50 mol) of 1,5-dihydroxynaphthalene, 100.1 g (0.40 mol) of 3,4-di-t-butoxybenzaldehyde, and 2-methoxy-1-propanol were placed in a 2,000 ml three-necked flask. After 600 g was made into a uniform solution at a liquid temperature of 80°C under a nitrogen atmosphere, 6.4 g of a 25% sodium hydroxide aqueous solution was slowly added and stirred at a liquid temperature of 110°C for 24 hours. After cooling to room temperature, 1,500 g of ethyl acetate was added, and the organic layer was washed with 300 g of a 3% nitric acid aqueous solution, and further washed with 300 g of pure water five times, followed by drying to dryness under reduced pressure. 400 mL of THF was added to the residue, and the polymer was reprecipitated with 3,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A3. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=2,900 and Mw/Mn=2.9. This polymer compound A3 has a repeating unit represented by the general formula (1).

[Synthesis example (A4)]
80 g (0.50 mol) of 1,5-dihydroxynaphthalene, 36.6 g (0.30 mol) of 4-hydroxybenzaldehyde, and 145 g of methyl cellosolve were added to a 1,000 mL flask, and p-toluenesulfonic acid was added while stirring at 70°C. of 20% by weight methyl cellosolve solution was added. After raising the temperature to 85° C. and stirring for 6 hours, the mixture was cooled to room temperature and diluted with 800 mL of ethyl acetate. It was transferred to a separating funnel and washed repeatedly with 200 mL of deionized water to remove the reaction catalyst and metal impurities. After the obtained solution was concentrated under reduced pressure, 600 mL of ethyl acetate was added to the residue, and the polymer was precipitated with 2,400 mL of hexane. The precipitated polymer was collected by filtration and dried under reduced pressure to obtain polymer compound A4. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=3,800 and Mw/Mn=2.4. This polymer compound A4 has a repeating unit represented by the general formula (1).

[Synthesis example (A5)]
80.1 g (0.50 mol) of 2,7-dihydroxynaphthalene, 100.1 g (0.40 mol) of terephthalaldehyde acid = t-butyl, and 600 g of 2-methoxy-1-propanol were placed in a 2,000 ml three-necked flask under nitrogen. After forming a uniform solution at a liquid temperature of 80° C. under an atmosphere, 6.4 g of a 25% sodium hydroxide aqueous solution was slowly added, and the mixture was stirred at a liquid temperature of 110° C. for 24 hours. After cooling to room temperature, 1,500 g of ethyl acetate was added, and the organic layer was washed with 300 g of a 3% nitric acid aqueous solution, and further washed with 300 g of pure water five times, followed by drying to dryness under reduced pressure. 400 mL of THF was added to the residue, and the polymer was reprecipitated with 3,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A5. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=2,900 and Mw/Mn=2.9. This polymer compound A5 has a repeating unit represented by the general formula (2).

[Synthesis example (A6)]
94.4 g (0.50 mol) of 6-hydroxy-2-naphthoic acid, 100.1 g (0.40 mol) of terephthalaldehyde acid = t-butyl, and 600 g of 2-methoxy-1-propanol were placed in a 2,000 ml three-necked flask. was made into a uniform solution at a liquid temperature of 80°C under a nitrogen atmosphere, 6.4 g of a 25% sodium hydroxide aqueous solution was slowly added, and the mixture was stirred at a liquid temperature of 110°C for 24 hours. After cooling to room temperature, 1,500 g of ethyl acetate was added, and the organic layer was washed with 300 g of a 3% nitric acid aqueous solution, and further washed with 300 g of pure water five times, followed by drying to dryness under reduced pressure. 400 mL of THF was added to the residue, and the polymer was reprecipitated with 3,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A6. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=3,500 and Mw/Mn=2.8. This polymer compound A6 has a repeating unit represented by the general formula (2).

[Synthesis example (A7)]
80.1 g (0.50 mol) of 1,5-dihydroxynaphthalene, 60.1 g (0.40 mol) of terephthalaldehyde acid, and 600 g of 2-methoxy-1-propanol were placed in a 2,000 ml three-necked flask under a nitrogen atmosphere. After making a uniform solution at a temperature of 80°C, 6.4 g of a 25% sodium hydroxide aqueous solution was slowly added, and the solution was stirred at a liquid temperature of 110°C for 24 hours. After cooling to room temperature, 1,500 g of ethyl acetate was added, and the organic layer was washed with 300 g of a 3% nitric acid aqueous solution, and further washed with 300 g of pure water five times, followed by drying to dryness under reduced pressure. 400 mL of THF was added to the residue, and the polymer was reprecipitated with 3,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A7. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=2,200 and Mw/Mn=2.9. This polymer compound A7 has a repeating unit represented by the general formula (2).

[Synthesis example (A8)]
9.4 g (0.05 mol) of 6-hydroxy-2-naphthoic acid, 5.3 g (0.05 mol) of terephthalaldehyde acid, and 60 g of 2-methoxy-1-propanol were placed in a 200 ml three-necked flask under a nitrogen atmosphere. After making a uniform solution at a temperature of 80°C, 0.6 g of a 25% sodium hydroxide aqueous solution was slowly added, and the solution was stirred at a liquid temperature of 110°C for 24 hours. After cooling to room temperature, 150 g of ethyl acetate was added, and the organic layer was washed with 30 g of a 3% aqueous nitric acid solution and then with 30 g of pure water five times, followed by drying to dryness under reduced pressure. 40 mL of THF was added to the residue, and the polymer was reprecipitated with 300 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A8. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=2,000 and Mw/Mn=2.6. This polymer compound A8 has a repeating unit represented by the general formula (2).

[Synthesis example (A9)]
54.1 g (0.50 mol) of o-cresol, 140.2 g (0.40 mol) of 3,4-bis(t-butoxycarbonylmethoxy)benzaldehyde, and 2-methoxy-1-propanol were placed in a 2,000 ml three-necked flask. After 600 g was made into a uniform solution at a liquid temperature of 80°C under a nitrogen atmosphere, 6.4 g of a 25% sodium hydroxide aqueous solution was slowly added and stirred at a liquid temperature of 110°C for 24 hours. After cooling to room temperature, 1,500 g of ethyl acetate was added, and the organic layer was washed with 300 g of a 3% nitric acid aqueous solution, and further washed with 300 g of pure water five times, followed by drying to dryness under reduced pressure. 400 mL of THF was added to the residue, and the polymer was reprecipitated with 3,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A9. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=3,200 and Mw/Mn=3.0. This polymer compound A9 has a repeating unit represented by the general formula (3).

[Synthesis example (A10)]
80.1 g (0.50 mol) of 1,6-dihydroxynaphthalene, 94.5 g (0.40 mol) of 4-t-butoxycarbonylmethoxybenzaldehyde, and 600 g of 2-methoxy-1-propanol were placed in a 2,000 ml three-necked flask. After making a uniform solution at a liquid temperature of 80° C. under a nitrogen atmosphere, 6.4 g of a 25% sodium hydroxide aqueous solution was slowly added, and the mixture was stirred at a liquid temperature of 110° C. for 24 hours. After cooling to room temperature, 1,500 g of ethyl acetate was added, and the organic layer was washed with 300 g of a 3% nitric acid aqueous solution, and further washed with 300 g of pure water five times, followed by drying to dryness under reduced pressure. 400 mL of THF was added to the residue, and the polymer was reprecipitated with 3,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound A10. When the weight average molecular weight (Mw) and the degree of dispersion (Mw/Mn) were determined by GPC, they were Mw=2,700 and Mw/Mn=2.7. This polymer compound A10 has a repeating unit represented by the general formula (3).

[Preparation of Organic Film-Forming Compositions (Sol.1-22)]
An organic solvent containing the above polymer compounds A1 to A10, cross-linking agents XL1 to XL3 as additives, thermal acid generator AG1, and surfactant FC-4430 (manufactured by Sumitomo 3M Co., Ltd.) 0.1% by mass is shown. 1 and filtered through a 0.1 μm fluororesin filter to prepare organic film-forming compositions (Sol. 1 to 22). In addition, Sol. 1 to 10, 15 to 16, and 20 to 22 are organic film-forming compositions for obtaining a substrate with a resist multilayer film of the present invention; Sol. Nos. 11 to 14 and 17 to 19 are organic film-forming compositions for comparison. Table 1 also shows the amount of the total amount of one or more selected from propylene glycol esters, ketones, and lactones in the prepared organic film-forming composition in the total organic solvent.

Thermal acid generator AG1 and cross-linking agents XL1 to XL3 are shown below.

Moreover, the organic solvent in Table 1 means the following.
PGMEA: propylene glycol methyl ether acetate Cyho: cyclohexanone PGEE: propylene glycol ethyl ether GBL: γ-butyrolactone 4M2P: 4-methyl-2-pentanol

[Solvent resistance evaluation]
Since the silicon-containing resist intermediate film is spin-coated directly on the organic film in the substrate with the resist multilayer film of the present invention, an organic solvent was used to examine whether the organic film to be formed is an organic film that does not cause intermixing. was evaluated for resistance to Each of the above organic film-forming compositions (Sol. 1 to 22) was coated on a silicon substrate, baked at 285° C. for 60 seconds to form an organic film, and the film thickness T1 was measured. After spin-coating PGMEA/PGME=30/70 (mass ratio) on the obtained organic film, heat treatment was performed at 100° C. for 30 seconds, and the film thickness T2 was measured. From these measurement results, the thickness reduction indicated by T1-T2 was calculated. Table 2 shows the results.

As shown in Table 2, Sol. Organic films formed from 1 to 10, 15 to 16 and 20 to 22 have sufficient organic solvent resistance. Therefore, it was found that even if a silicon-containing resist intermediate film is spin-coated directly on these organic films, a laminated film can be formed without intermixing.

[Evaluation of film formability on organic resist underlayer film]
Since the organic film in the resist multilayer-coated substrate of the present invention is laminated on the organic resist underlayer film, the film-forming property on the organic resist underlayer film was confirmed. A silicon wafer was coated with a spin-on carbon film ODL-102 manufactured by Shin-Etsu Chemical Co., Ltd. as an organic resist underlayer film to form an organic resist underlayer film having a thickness of 200 nm. Organic film-forming compositions (Sol. 1 to 22) were applied thereon and baked at 285° C. for 60 seconds to form an organic film, and the state of formation of the organic film was confirmed. Table 3 shows the results.

As shown in Table 3, Sol. 1 to 10, 15 to 16, and 20 to 22 could be formed on the organic resist underlayer film by spin coating without film formation failure. On the other hand, Sol. In Nos. 11 to 14 and 17 to 19, repelling occurred on the organic resist underlayer film, and the film could not be laminated.

[Wet removability of organic film with ammonia water]
Each of the above organic film-forming compositions (Sol. 1 to 10, 15 to 16) is coated on a silicon substrate and baked at 285° C. for 60 seconds to form an organic film having a thickness of 25 nm. was measured. This film was mixed with 29% ammonia water/35% hydrogen peroxide water/water=1/1/8, immersed in ammonia overwater maintained at 65° C. for 5 minutes, washed with pure water, and then heated at 100° C. for 60 seconds. It was dried by heating, and the film thickness T3 was measured. Also, the film removal rate at this time was obtained. These results are shown in Table 4.

As shown in Table 4, Sol. It was found that the organic films formed from 1 to 10 and 15 to 16 can be removed with ammonia hydrogen peroxide at a rate of 5 nm/min or more.

[Production of Substrate with Resist Multilayer Film and Evaluation of Residue After Organic Resist Underlayer Film Ashing]
(Examples 1 to 15 and Comparative Example 1)
A spin-on carbon film ODL-102 manufactured by Shin-Etsu Chemical Co., Ltd. was formed as an organic resist underlayer film on a silicon wafer with a film thickness of 200 nm. Organic film-forming compositions (Sol. 1 to 10, 15 to 16, 20 to 22) were applied thereon, respectively, and heated at 285° C. for 60 seconds to laminate an organic film. On the other hand, as described above, Sol. In Nos. 11 to 14 and 17 to 19, repelling occurred on the organic resist underlayer film, and the film could not be laminated (that is, the substrate with the resist multilayer film of the present invention could not be produced), so an organic film was introduced. Comparative Example 1 was taken as Comparative Example 1.

Next, a composition for forming a silicon-containing resist intermediate film (SiARC-1) shown in Table 5 below was applied and heated at 220° C. for 60 seconds to laminate a silicon-containing resist intermediate film having a thickness of 35 nm. A positive development ArF resist solution (PR-1) shown in Table 6 below was applied thereon and heated at 110° C. for 60 seconds to form a photoresist film with a thickness of 100 nm as a resist upper layer film. A substrate with a film was obtained. Further, the liquid immersion protective film composition (TC-1) shown in Table 7 below was coated on the photoresist film and heated at 90° C. for 60 seconds to form a protective film having a thickness of 50 nm.

Subsequently, these wafers were exposed with an ArF immersion exposure apparatus (Nikon Corporation NSR-S610C, NA 1.30, σ 0.98/0.65, 35-degree dipole polarized illumination, 6% halftone phase shift mask). Then, it was baked (PEB) at 100° C. for 60 seconds and developed with a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds to obtain a 160 nm 1:1 positive type line-and-space pattern. For the wafer thus obtained, the cross-sectional shape of the pattern was examined with an electron microscope (S-4800) manufactured by Hitachi, Ltd., and the collapse of the pattern was examined with an electron microscope (CG4000) manufactured by Hitachi High-Technologies Corporation. Observed.

These wafers on which the photoresist pattern was obtained were subjected to dry etching under the processing conditions shown in Tables 8 and 9 using Tokyo Electron's etching apparatus Telus to form a silicon-containing resist intermediate film and an organic resist underlayer film, respectively. processed. In addition, the cross-sectional shape of the pattern on the obtained wafer was observed with an electron microscope (S-9380, manufactured by Hitachi, Ltd.).

Next, in order to wet-remove the silicon-containing resist intermediate film remaining after processing the organic resist underlayer film, the above wafer was mixed with 29% ammonia water/35% hydrogen peroxide water/water=1/1/8 and heated to 65°C. The mixture was treated with ammonia hydrogen peroxide kept at constant temperature for 5 minutes. After the treatment, it was washed with pure water and dried by heating at 100° C. for 60 seconds. In addition, in order to confirm whether the silicon content was removed by the ammonia hydrogen peroxide treatment, the surface of the organic resist underlayer film was subjected to XPS analysis using K-ALPHA manufactured by Thermo Fisher Scientific Co., Ltd., and the amount of silicon on the organic resist underlayer film was quantified. did.

The organic resist underlayer film pattern obtained by the above steps was processed under the processing conditions shown in Table 10 using an etching apparatus Telus manufactured by Tokyo Electron to remove the remaining organic resist underlayer film by ashing. After the ashing treatment, the wafer was observed with an electron microscope (CG4000, manufactured by Hitachi High-Technologies Corporation) to confirm the presence or absence of residues. Table 11 shows the results.

The composition of the silicon-containing resist intermediate film-forming composition (SiARC-1) is shown in Table 5 below.

ＴＰＳＮＯ_３：硝酸トリフェニルスルホニウム

TPSNO ₃ : triphenylsulfonium nitrate

The molecular weight and structural formula of SiARC polymer 1 shown in Table 5 are shown below.
SiARC polymer 1: molecular weight (Mw) = 2,800

The molecular weight and structural formula of SiARC polymer 2 shown in Table 5 are shown below.
SiARC polymer 2: molecular weight (Mw) = 2,800

The composition of the above ArF resist solution for positive development (PR-1) is shown in Table 6 below.

The molecular weight, dispersity, and structural formula of ArF resist polymer 1 shown in Table 6 are shown below.
ArF resist polymer 1: molecular weight (Mw) = 7,800
Dispersity (Mw/Mn) = 1.78

Acid generator shown in Table 6: The structural formula of PAG1 is shown below.

The structural formulas of the bases shown in Table 6: Quencher are shown below.

Table 7 below shows the composition of the liquid immersion protective film composition (TC-1) used in the above patterning test by positive development.

The molecular weights, dispersities, and structural formulas of the overcoat polymers shown in Table 7 above are shown below.
Protective film polymer: molecular weight (Mw) = 8,800
Dispersity (Mw/Mn) = 1.69

Dry etching processing conditions for the silicon-containing resist intermediate film are shown in Table 8 below.

The dry etching processing conditions for the organic resist underlayer film are shown in Table 9 below.

Table 10 below shows the ashing removal conditions for the organic resist underlayer film.

Observation results of the cross-sectional shape of the photoresist pattern and the collapse of the pattern obtained in the above evaluation, observation results of the cross-sectional shape of the pattern after dry etching processing, silicon remaining amount on the surface of the organic resist underlayer film after ammonia water treatment, Table 11 below shows the presence or absence of residue after ashing the organic resist underlayer film pattern.

As shown in Table 11, Sol. In Examples 1 to 12 in which the organic films formed from 1 to 10 and 15 to 16 were introduced, no silicon remained on the organic resist underlayer film after the ammonia hydrogen peroxide treatment, and no residue was left after the organic resist underlayer film pattern was ashed. no longer occurs. Further, when the influence of the film thickness of the organic film was confirmed in Examples 13 to 15 and Comparative Example 1, as shown in Example 13, when the organic film was thin, the organic resist after the ammonia hydrogen peroxide treatment No residue of silicon was found on the surface of the underlayer film, and no residue was generated after the organic resist underlayer film pattern was ashed. Moreover, as shown in Example 15, when the film was thick, the organic film portion was side-etched during the dry etching process, but no residue was generated after the organic resist underlayer film pattern was ashed. On the other hand, as shown in Comparative Example 1, when there was no organic film, the effect of removing the silicon residue was not obtained, and the residue was generated after the organic resist underlayer film pattern was ashed.

As described above, the substrate with a resist multilayer film of the present invention can be easily wet-processed with a silicon residue denatured by dry etching using a stripping solution that does not damage the semiconductor device substrate or the organic resist underlayer film required in the patterning process. It has become clear that it has a removable organic film and that it can be applied as an ion-implantation shielding mask material when forming a three-dimensional transistor. In particular, by introducing an organic film with a film thickness of 10 nm or more and less than 100 nm, it has become clear that a processing process that does not generate residues can be constructed more reliably. As a result, it becomes possible to prevent a decrease in yield in the manufacturing process of the three-dimensional transistor, and it becomes possible to economically manufacture a semiconductor device with higher performance.

It should be noted that the present invention is not limited to the above embodiments. The above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect is the present invention. included in the technical scope of

Claims (8)

A substrate with a resist multilayer film comprising a substrate and a resist multilayer film formed on the substrate,
The resist multilayer film comprises, from the substrate side, an organic resist lower layer film sparingly soluble in ammonia hydrogen peroxide water, an organic film soluble in ammonia hydrogen peroxide water, a silicon-containing resist intermediate film, and a resist upper layer film in this order. and
A composition for forming an organic film, wherein the organic film soluble in ammonia hydrogen peroxide mixture contains a polymer compound having at least one repeating unit represented by any one of the following general formulas (1) to (4), and an organic solvent. is a cured product of, and
The organic resist underlayer film, which is poorly soluble in ammonia hydrogen peroxide, is immersed in a solution of 29% ammonia water/35% hydrogen peroxide water/water (=1/1/8) at 65° C., so that the A substrate with a resist multilayer film, characterized by having a dissolution rate .

(In the formula, R ₁ is a hydrocarbon group having 1 to 19 carbon atoms, a halogen atom, an alkoxy group, a carboxy group, a sulfo group, a methoxycarbonyl group, a hydroxyphenyl group, or an amino group, and R ₂ is a hydrogen atom or AL AL is a group that generates an acidic functional group by the action of heat or acid, and R ₃ is a hydrogen atom, a furanyl group, or a carbonized group having 1 to 16 carbon atoms which may have a chlorine atom or a nitro group. is a hydrogen group, k ₁ , k ₂ and k ₃ are 1 to 2, l is 1 to 3, m is 0 to 3, and n is 0 or 1, provided that the polymer The compound is not m-cresol novolac.) 2. The substrate with a resist multilayer film according to claim 1 , wherein the composition for forming an organic film further contains either or both of a thermal acid generator and a cross-linking agent. The organic film soluble in ammonia hydrogen peroxide is immersed in a solution of 29% ammonia water/35% hydrogen peroxide water/water = 1/1/8 at 65°C to achieve a dissolution rate of 5 nm/min or more. 3. The substrate with a resist multilayer film according to claim 1 or 2 , characterized in that it has a 4. The substrate with a resist multilayer film according to claim 1, wherein the thickness of the organic film soluble in ammonia peroxide water is 10 nm or more and less than 100 nm. 5. The substrate with a resist multilayer film according to any one of claims 1 to 4 , wherein the silicon-containing resist intermediate film contains one or both of boron and phosphorus. A method for manufacturing a substrate with a resist multilayer film according to any one of claims 1 to 5,
The organic film-forming composition is characterized in that, in the organic solvent, the total amount of one or more selected from propylene glycol esters, ketones, and lactones accounts for more than 30% by weight in the total organic solvent. A method for manufacturing a substrate with a resist multilayer film. The resist upper layer film of the substrate with a resist multilayer film according to any one of claims 1 to 5 is exposed and developed with a developer to form a pattern on the resist upper layer film, and the pattern is formed. The silicon-containing resist intermediate film is etched using the resist upper layer film as an etching mask to form a pattern, and the silicon-containing resist intermediate film with the pattern formed thereon is used as an etching mask to etch the organic film and the organic resist lower layer film. The patterned silicon-containing resist intermediate film and the patterned organic film are removed by treatment with ammonia hydrogen peroxide mixture, and the patterned organic resist underlayer film is used as a mask. A pattern forming method, comprising forming a pattern on the substrate. 8. The pattern forming method according to claim 7 , wherein after the pattern is formed on the substrate, the organic resist underlayer film on which the pattern is formed is removed by dry etching or wet etching.