# Patent

## Title
Resist under layer film composition and patterning process

## Abstract

The present invention provides a resist under layer film composition containing a novolak resin having a repeating unit shown by the formula (1) and either or both of a novolak resin having a repeating unit shown by the formula (2) and a bisnaphthol derivative shown by the formula (3). There is provided a resist under layer film composition that is excellent in filling property, generates little outgas, and has excellent dry etching resistance and heat resistance.

## Background
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a resist under layer film composition for fine patterning in a manufacturing process of a semiconductor apparatus and the like, and to a patterning process.
Description of the Related Art
In recent years, double patterning which includes repeating lithography and etching steps (LELE, Litho-Etch-Litho-Etch) has been used to form interconnect with high density by three-dimensional gate such as ultra-fine and dense Fin-field effect transistor (Fin-FET) or dual damascene, in which trenches and vias of copper interconnect are formed at the same time. Accordingly, materials capable of filling gaps with high aspect ratio and high density have been demanded. Filling gaps makes the film surface flatten and facilitates focus leveling in lithography, thus enabling patterning with an adequate margin even if the focus margin is narrow.
A spin coating method has been commonly used for planarizing a substrate having gaps. Otherwise, the gaps can be filled by forming an amorphous carbon film by chemical vapor deposition (CVD) method, but this method has a disadvantage of process cost because the surface becomes uneven and the film surface is required to be ground by chemical mechanical polishing (CMP) method to planarize it. Moreover, there is a problem that the amorphous carbon film formed by the CVD method fails to fill ultra-fine gaps with a pitch of 50 nm or less because voids occur in the bottom of the gaps. The ultra-fine gaps with a pitch of 50 nm or less can be filled by spin coating of a material containing a large amount of low molecular weight components.
A liquid immersion lithography makes an angle of incident light to a resist and an underlying layer(s) shallower and substrate reflection larger. To suppress the substrate reflection, a multi-layer antireflection film is effectively formed under the resist. A 3-layer (tri-layer) structure in which a hydrocarbon film (a resist under layer film) with high carbon density is formed on a substrate, a silicon-containing resist middle layer film is formed thereon, and a resist upper layer film is formed thereon can prevent the substrate reflection by the two layers of the hydrocarbon film and the silicon-containing middle layer film. Thus, the application of this technique has been rapidly spreading with use of the liquid immersion lithography.
The resist under layer film is required to have functions such as filling and planarizing properties by spin coating, high dry-etching resistance for dry etching a substrate, and optimum optical properties for providing high antireflection effect.
The resist under layer film is also required to have high heat resistance in some cases, for example, when a hard mask layer such as p-Si, SiN, SiON, TiN, ZrO2, and HfO2 is formed on the resist under layer film because these films need a temperature exceeding 300° C. to be formed.
Examples of a resist under layer film material with high heat resistance include a bisnaphthol compound and a novolak resin thereof disclosed in Patent Document 1, bisnaphthol fluorene and a novolak resin thereof disclosed in Patent Document 2, a novolak resin of naphthol phthalein disclosed in Patent Document 3, and a novolak resin of naphthofluorescein disclosed in Patent Document 4.
In addition, there is a problem of outgas generated in baking for forming a resist under layer film. The outgas component adheres to an upper plate above a hot plate, and when the component drops onto a wafer, a defect is generated. To improve the property of filling gaps of a substrate, monomer components (low molecular weight components) are effectively added to the resist under layer film composition. However, the more the monomer components are added, the more outgas is generated in baking at high temperature. In other words, there is a trade-off relationship between the improvement in filling property and the reduction in outgas. Therefore, a resist under layer film composition that can overcome the trade-off relationship has been demanded.
PRIOR ART DOCUMENTS
Patent Documents
[Patent Document 1] Japanese Patent No. 4659678
[Patent Document 2] Japanese Patent No. 5336306
[Patent Document 3] Japanese Patent Laid-Open Publication No. 2015-018221
[Patent Document 4] Japanese Patent Laid-Open Publication No. 2015-018223
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of the above circumstances, and an object thereof is to provide a resist under layer film composition that has good filling property, generates little outgas, and is excellent in dry-etching resistance and heat resistance.
To achieve this object, the present invention provides a resist under layer film composition comprising a novolak resin having a repeating unit shown by the formula (1) and either or both of a novolak resin having a repeating unit shown by the formula (2) and a bisnaphthol derivative shown by the formula (3),




wherein R1 and R2 represent a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms, in which the alkyl group, the alkenyl group, the aryl group, and the aralkyl group may contain a fluorine atom(s) and may further contain a hydroxyl group, an alkoxy group, an acyl group, a sulfoxide group, a sulfo group, or an ester bond, and 10% or more of a total of R1 and R2 are groups containing at least one fluorine atom; R3, R4, R11, and R22 represent a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, in which the alkyl group, the alkenyl group, and the aryl group may contain a hydroxyl group, an alkoxy group, an acyloxy group, an ether group, or a sulfide group; R18 and R19 represent a halogen atom or the same group as R3, R4, R11, and R12; R5, R6, R23, R24, R20, and R21 represent a hydrogen atom, or R5, R13, and R20 may bond to R6, R14, and R21 respectively to form an ether bond; R7 and R15 represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, in which the alkyl group, the alkenyl group, and the aryl group may contain a hydroxyl group, an alkoxy group, an acyloxy group, an ether group, a sulfide group, a chloro group, or a nitro group; R9, R10, R16, and R17 represent a hydrogen atom, an acid-labile group, a glycidyl group, or a linear, branched, or cyclic alkyl, acyl, or alkoxycarbonyl group having 1 to 10 carbon atoms; X1, X2, and X3 represent a single bond or a linear, branched, or cyclic divalent hydrocarbon group having 1 to 38 carbon atoms and optionally containing a hydroxyl group, a carboxyl group, an ether group, or a lactone ring, when X1 is a divalent hydrocarbon group, R5 and R6 may bond to carbon atoms in X1 to form an ether bond, when X2 is a divalent hydrocarbon group, R13 and R14 may bond to carbon atoms in X2 to form an ether bond, and when X3 is a divalent hydrocarbon group, R20 and R21 may bond to carbon atoms in X3 to form an ether bond; and a, b, c, d, g, h, i, j, k, l, m, and n are each 1 or 2.

Such a resist under layer film composition has good filling property, generates little outgas, and is excellent in dry-etching resistance and heat resistance.
The resist under layer film composition preferably comprises the novolak resin having the repeating unit shown by the formula (1), the novolak resin having the repeating unit shown by the formula (2), and the bisnaphthol derivative shown by the formula (3).
The composition containing all three components of the novolak resin having the repeating unit shown by the formula (1), the novolak resin having the repeating unit shown by the formula (2), and the bisnaphthol derivative shown by the formula (3) can achieve the improvement in filling property and the reduction in outgas with good balance.
The novolak resin having the repeating unit shown by the formula (1) preferably contains one or more groups selected from the formulae (4)-1 to (4)-5 as R1 and/or R2 in the formula (1),




wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R0 represents a hydrogen atom, a methyl group, an acetyl group, or a trifluoroacetyl group; Rf represents a fluorine atom, a linear, branched, or cyclic alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon, an aralkyl group having 7 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, in which these groups contain at least one fluorine atom and may further contain a hydroxyl group or an alkoxy group; R22 represents a hydrogen atom, a methyl group, or an ethyl group; and R23 and R24 represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

When such groups are contained, the amount of outgas generated from the resist under layer film composition can be further reduced. [0017]
A total amount of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3) is preferably 5 to 100 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1).
Such a ratio enables the improvement in filling property and the reduction in outgas to be achieved with particularly good balance.
The resist under layer film composition preferably further comprises an organic solvent.
The organic solvent enables the concentration and the viscosity of the resist under layer film composition to be adjusted, and improves compatibility.
The resist under layer film composition preferably further comprises an acid generator and/or a crosslinking agent.
These components promote crosslinking curing reaction of the resist under layer film composition.
Furthermore, the present invention provides a patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the above-described resist under layer film composition; forming a silicon-containing middle layer film on the resist under layer film by using a silicon-containing middle layer film composition; forming a resist upper layer film on the silicon-containing middle layer film by using a resist upper layer film composition; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the silicon-containing middle layer film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the silicon-containing resist middle layer film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.
Furthermore, the present invention provides a patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the above-described resist under layer film composition; forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film on the resist under layer film; forming a resist upper layer film on the inorganic hard mask intermediate film by using a resist upper layer film composition; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the inorganic hard mask intermediate film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the inorganic hard mask intermediate film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.
Furthermore, the present invention provides a patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the above-described resist under layer film composition; forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film on the resist under layer film; forming an organic antireflection film on the inorganic hard mask intermediate film; forming a resist upper layer film on the organic antireflection film by using a resist upper layer film composition, thereby forming a 4-layer resist film; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the organic antireflection film and the inorganic hard mask intermediate film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the inorganic hard mask intermediate film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.
Furthermore, the present invention provides a patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the above-described resist under layer film composition; forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film on the resist under layer film; forming a hydrocarbon film on the inorganic hard mask intermediate film by using a hydrocarbon film composition by spin coating; forming a silicon-containing middle layer film on the hydrocarbon film by using a silicon-containing middle layer film composition; forming a resist upper layer film on the silicon-containing middle layer film by using a resist upper layer film composition, thereby forming a S-layer resist film; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the silicon-containing middle layer film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the hydrocarbon film by etching using the silicon-containing middle layer film having the transferred pattern as a mask; transferring the pattern to the inorganic hard mask intermediate film by etching using the hydrocarbon film having the transferred pattern as a mask; transferring the pattern to the resist under layer film by etching using the inorganic hard mask intermediate film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.
The patterning process using the inventive resist under layer film composition that has good filling property, generates little outgas, and is excellent in dry-etching resistance and heat resistance can significantly reduce defects at fine processing in the manufacturing process of a semiconductor apparatus and the like.
The inorganic hard mask intermediate film is preferably formed by a CVD method, an ALD method, or a sputtering method.
Such methods are suitable for forming the inorganic hard mask intermediate film.
It is preferred that the resist upper layer film composition do not contain a polymer having a silicon atom, and the etching of the resist under layer film using the silicon-containing middle layer film or the inorganic hard mask intermediate film as a mask be performed with an etching gas containing an oxygen gas or a hydrogen gas.
In this manner, removal of the resist upper layer film and etching of the resist under layer film can be performed at the same time.
As mentioned above, the inventive resist under layer film composition has good filling property, generates little outgas, and can form a resist under layer film having excellent dry-etching resistance and heat resistance. The resist under layer film is also improved in film thickness uniformity. In addition, the inventive patterning process using such a resist under layer film composition allows a substrate to be sufficiently embedded, prevents generation of outgas, and thus significantly reduces defects at fine processing in the manufacturing process of a semiconductor apparatus and the like. Accordingly, the resist under layer film composition and the patterning process of the present invention are especially suitable for manufacturing a three-dimension device such as Fin-FET, which requires filling a trench pattern having narrow pitch and inhibiting generation of outgas during baking of the resist under layer film that may cause defects.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A to 1F show an example of the inventive patterning process by 3-layer process using a silicon-containing middle layer film. FIG. 1A shows a step of forming a multi-layer film. FIG. 1B shows a step of exposure. FIG. 1C shows a step of development. FIG. 1D shows a step of transferring the resist pattern. FIG. 1E shows a step of transferring the silicon-containing middle layer film pattern. FIG. 1F shows a step of transferring the resist under layer film pattern.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As mentioned above, it has been desired to develop a resist under layer film composition that has good filling property and generates little outgas. To improve filling property, monomer components are effectively added to the resist under layer film composition. However, when monomer components are added, the monomer components evaporate at baking to generate outgas, and the outgas adheres to an upper plate above a hot plate. Drop of the substance adhering to the upper plate causes a defect, so that the improvement performance in filling property and the outgas prevention performance have a trade-off relationship. The present inventors have intensively studied to formulate a resist under layer film composition that has good filling property and generates little outgas, and found that a resist under layer film in which the side of a substrate with gaps contains many monomer components required for filling, and the surface layer side contains many polymer components is effective in both the improvement in filling property and the inhibition of outgas generation.
The present inventors have further studied and consequently found that a resist under layer film composition containing a novolak resin having a repeating unit shown by the formula (1) and either or both of a novolak resin having a repeating unit shown by the formula (2) and a bisnaphthol derivative shown by the formula (3) can improve filling property and inhibit generation of outgas even if the composition contains a large amount of monomer components, thereby brought the present invention to completion.
That is, the present invention is a resist under layer film composition comprising a novolak resin having a repeating unit shown by the formula (1) and either or both of a novolak resin having a repeating unit shown by the formula (2) and a bisnaphthol derivative shown by the formula (3),




wherein R1 and R2 represent a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms, in which the alkyl group, the alkenyl group, the aryl group, and the aralkyl group may contain a fluorine atom(s) and may further contain a hydroxyl group, an alkoxy group, an acyl group, a sulfoxide group, a sulfo group, or an ester bond, and 10% or more of a total of R1 and R2 are groups containing at least one fluorine atom; R3, R4, R11, and R12 represent a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, in which the alkyl group, the alkenyl group, and the aryl group may contain a hydroxyl group, an alkoxy group, an acyloxy group, an ether group, or a sulfide group; R18 and R19 represent a halogen atom or the same group as R3, R4, R11, and R12; R5, R6, R13, R14, R20, and R21 represent a hydrogen atom, or R5, R13, and R20 may bond to R6, R14, and R21 respectively to form an ether bond; R7 and R15 represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, in which the alkyl group, the alkenyl group, and the aryl group may contain a hydroxyl group, an alkoxy group, an acyloxy group, an ether group, a sulfide group, a chloro group, or a nitro group; R9, R10, R16, and R17 represent a hydrogen atom, an acid-labile group, a glycidyl group, or a linear, branched, or cyclic alkyl, acyl, or alkoxycarbonyl group having 1 to 10 carbon atoms; X1, X2, and X3 represent a single bond or a linear, branched, or cyclic divalent hydrocarbon group having 1 to 38 carbon atoms and optionally containing a hydroxyl group, a carboxyl group, an ether group, or a lactone ring, when X1 is a divalent hydrocarbon group, R5 and R6 may bond to carbon atoms in X1 to form an ether bond, when X2 is a divalent hydrocarbon group, R13 and R14 may bond to carbon atoms in X2 to form an ether bond, and when X3 is a divalent hydrocarbon group, R20 and R21 may bond to carbon atoms in X3 to form an ether bond; and a, b, c, d, g, h, i, j, k, l, m, and n are each 1 or 2.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.
<Resist Under Layer Film Composition>
The inventive resist under layer film composition contains the novolak resin having the repeating unit shown by the formula (1) and either or both of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3). When such a resist under layer film composition is used, the novolak resin containing the repeating unit shown by the formula (1) with fluorine atoms in a prescribed amount or more covers the film surface during spin coating. The presence of the fluorine-containing layer enables generation of outgas to be inhibited even when the resist under layer film composition containing monomer components for improving filling property is baked at high temperature.
The property of filling gaps of a substrate is further improved by adding the bisnaphthol derivative shown by the formula (3) as a monomer component. Generally, addition of such a monomer component increases generation of outgas in baking. However, as mentioned above, in the inventive resist under layer film composition, the novolak resin containing the repeating unit shown by the formula (1) with fluorine atoms in a prescribed amount or more moves to the surface of the resist under layer film at coating, and a resin layer containing a large amount of this resin is formed at the surface of the resist under layer film. Since the resist under layer film surface is coated with the resin layer of the fluorine-containing bisnaphthol novolak resin, even when monomer components are contained, it is possible to inhibit the monomer components from evaporating from the resist under layer film surface and causing outgas during baking. This is an effective means to inhibit generation of outgas and improve filling property. Filling property can be further improved by increasing the amount of monomer components or using lower molecular weight components.
In addition, formation of the fluorine-containing layer at the resist under layer film surface is also effective in prevention of damage to the resist under layer film surface when a silicon-containing middle layer film (SOG film) on the resist under layer film is removed with a hydrofluoric acid aqueous solution or when a TiN film or a Boron Phosphorus Silicate Glass (BPSG) film is removed with an alkali removing liquid, Standard Clean (SC) 1. This is because water-repellency of fluorine can prevent the hydrofluoric acid aqueous solution and the SC1 from soaking into the resist under layer film.
Further advantageously, a naphthalene ring can inhibit reflection from the resist under layer film because of its relatively small absorption at 193 nm wavelength of ArF excimer laser, and exhibits high dry-etching resistance because it is a condensed aromatic ring.
In some cases, above the resist under layer film, not only a silicon-containing middle layer film is formed by spin coating, but also an inorganic film, such as a SiON film and a TiN film, which serves as both an antireflection film and a hard mask is formed. The SiON film has not only excellent antireflection effect but also higher dry-etching resistance than the silicon-containing middle layer film formed by spin coating. The TiN film has advantages of high dry-etching resistance and removability with an alkali removing liquid such as SC1. Since the SiON film and the TiN film require a substrate temperature of 300° C. or higher to be formed, a resist under layer film having inadequate heat resistance cannot be used in a method including forming such an inorganic film even if the dry-etching resistance and other properties are excellent. By contrast, a resist under layer film formed from the inventive resist under layer film composition has adequate heat resistance, so that it can be suitably used even when an inorganic film that needs to be heated at 300° C. or higher is formed, as mentioned above.
When an under layer film solution is applied onto a substrate having gaps, for example, a hole pattern, bubbles exist in the bottoms of the holes just after the application, and the bottoms of the holes are filled after baking at high temperature. This indicates that the resin flows to fill the bottoms of the holes in baking, and the bubbles (voids) move toward the under layer film surface and then disappear.
In general, when a solution containing a resin is applied by spin coating at a low speed of 500 rpm or less and the solvent is then evaporated by baking, the film thickness becomes nonuniform. By contrast, when the solution is applied by spin coating at 700 rpm or more, phenomenon of thickness nonuniformity does not occur. The phenomenon that film thickness becomes nonuniform by low speed spin coating followed by baking is attributable to Marangoni effect.
Marangoni effect is supposed to occur also when an under layer film resin is baked at high temperature. In the case that a resin material composed of only monomers is used, pull-back phenomenon from wafer edge and the phenomenon of nonuniform thickness after coating can be explained by Marangoni effect. Movement of a high-temperature substance, which has low surface tension, toward the film surface decreases temperature, thereby increasing the surface tension. In general, a film in which the film surface is covered with a material having low surface tension is energetically stable. Conversely, Marangoni effect makes the film energetically unstable, resulting in thickness nonuniformity.
By contrast, the inventive resist under layer film composition contains a fluorine-containing material with low surface tension (i.e., the novolak resin having the repeating unit shown by the formula (1)). Therefore, the film surface is covered with the material with low surface tension, which resolves instability due to Marangoni effect. In other words, film thickness uniformity can also be improved.
As mentioned above, the inventive resist under layer film composition contains the novolak resin having the repeating unit shown by the formula (1) as an essential component and either or both of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3). That is, the composition may contain the novolak resin having the repeating unit shown by the formula (1) and the novolak resin having the repeating unit shown by the formula (2) but not the bisnaphthol derivative shown by the formula (3), or may contain the novolak resin having the repeating unit shown by the formula (1) and the bisnaphthol derivative shown by the formula (3) but not the novolak resin having the repeating unit shown by the formula (2). Alternatively, the composition may contain all three components of the novolak resin having the repeating unit shown by the formula (1), the novolak resin having the repeating unit shown by the formula (2), and the bisnaphthol derivative shown by the formula (3).
Above all, the composition preferably contains all three components of the novolak resin having the repeating unit shown by the formula (1), the novolak resin having the repeating unit shown by the formula (2), and the bisnaphthol derivative shown by the formula (3).
When the composition contains all three components of the novolak resin having the repeating unit shown by the formula (1), the novolak resin having the repeating unit shown by the formula (2), and the bisnaphthol derivative shown by the formula (3), both the improvement in filling property and the reduction in outgas can be achieved with better balance.
Illustrative examples of the linear, branched, or cyclic divalent hydrocarbon group having 1 to 38 carbon atoms represented by X1, X2, and X3 include linear, branched, or cyclic alkylene, arylene, and aralkylene groups having 1 to 38 carbon atoms.
Illustrative examples of a bisnaphthol derivative usable as a monomer to give the novolak resins having the repeating unit shown by the formula (1) or (2) include the following compounds. The following compounds can also be used as the bisnaphthol derivative shown by the formula (3).


























































In these formulae, R25 represents R1, R9, or R16, and R26 represents R2, R10, or R17. The bisnaphthol derivative to give the novolak resin having the repeating unit shown by the formula (1) or (2) may be the same as or different from the bisnaphthol derivative shown by the formula (3) for improving filling property.
When R9, R10, R16, and R17 are acid-labile groups, these groups may be the same or different. Examples thereof include groups shown by the formulae (A-1) to (A-3).




In the formula (A-1), RL30 represents a tertiary alkyl group having 4 to 20, preferably 4 to 15 carbon atoms, a trialkylsilyl group containing alkyl groups having 1 to 6 carbon atoms, an oxoalkyl group having 4 to 20 carbon atoms, or a substituent shown by the formula (A-3). Illustrative examples of the tertiary alkyl group include a tert-butyl group, a tert-amyl group, a 1,1-diethylpropyl group, a 1-ethylcyclopentyl group, a 1-butylcyclopentyl group, a 1-ethylcyclohexyl group, a 1-butylcyclohexyl group, a 1-ethyl-2-cyclopentenyl group, a 1-ethyl-2-cyclohexenyl group, and a 2-methyl-2-adamantyl group; illustrative examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, and a dimethyl-tert-butylsilyl group; and illustrative examples of the oxoalkyl group include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxane-4-yl group, and a 5-methyl-2-oxooxolane-5-yl group. A1 is an integer of 0 to 6.
Illustrative examples of the acid-labile group of the formula (A-1) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-amyloxycarbonyl group, a tert-amyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.
Other examples of the tertiary alkyl group include substituents shown by the formulae (A-1)-1 to (A-1)-10.







In these formulae, each RL37 may be the same or different, and represents a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 17 carbon atoms; RL38 represents a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms; each RL39 may be the same or different, and represents a linear, branched, or cyclic alkyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms; and A1 has the same meaning as above.
In the formula (A-2), RL31 and RL32 represent a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 18, preferably 1 to 10 carbon atoms. Illustrative examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and a n-octyl group. RL33 represents a monovalent hydrocarbon group having 1 to 18, preferably 1 to 10 carbon atoms, and optionally containing a heteroatom such as an oxygen atom. For example, there may be mentioned a linear, branched, or cyclic alkyl group and a group in which a part of hydrogen atoms in these groups is substituted with a hydroxyl group, an alkoxy group, an oxo group, an amino group, an alkylamino group, or the like. Illustrative examples thereof include the following substituted alkyl groups.




RL31 and RL32, RL31 and RL33, and RL32 and RL33 may be bonded to form a ring together with the carbon atoms to which these groups are bonded; and when the ring is formed, each of RL31, RL32, and RL33 that participate in the ring formation represents a linear or branched alkylene group having 1 to 18, preferably 1 to 10 carbon atoms. The carbon number in the ring is preferably 3 to 10, particularly preferably 4 to 10.
Among the acid-labile group shown by the formula (A-2), illustrative examples of the linear or branched one include groups of the following formulae (A-2)-1 to (A-2)-69.






















Among the acid-labile groups shown by the formula (A-2), illustrative examples of the cyclic one include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, and a 2-methyltetrahydropyran-2-yl group.
The base resins of the novolak resin having the repeating unit shown by the formula (2) may be linked through a crosslinking acetal group shown by the formula (A-2a) or (A-2b) to form intermolecular or intramolecular crosslinking.




In these formulae, RL40 and RL41 represent a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms. Alternatively, RL40 and RL41 may be bonded to form a ring together with the carbon atoms to which these groups are bonded. When the ring is formed, RL40 and RL41 represent a linear or branched alkylene group having 1 to 8 carbon atoms. RL42 represents a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms. B1 and D1 represent an integer of 0 to 10, preferably 0 to 5. C1 represents an integer of 1 to 7, preferably 1 to 3.
In these formulae, “A” represents an aliphatic or alicyclic saturated hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group having 1 to 50 carbon atoms with a valency of (C1+1); these groups may contain a heteroatom, or a part of hydrogen atoms bonded to the carbon atom in these groups may be substituted with a hydroxyl group, a carboxyl group, a carbonyl group, or a fluorine atom. “A” is preferably a linear, branched, or cyclic alkylene group, alkyltriyl group, alkyltetrayl group having 2 to 4 valency and 1 to 20 carbon atoms, or an arylene group having 6 to 30 carbon atoms; these group may contain a heteroatom, or a part of hydrogen atoms bonded to the carbon atom in these groups may be substituted with a hydroxyl group, a carboxyl group, an acyl group, or a halogen atom. “B” represents —CO—O—, —NHCO—O—, or —NHCONH—.
Illustrative examples of the crosslinking acetal group shown by the formulae (A-2a) and (A-2b) include groups of the following formulae (A-2)-70 to (A-2)-77.




In the formula (A-3), RL34, RL35, and RL36 represent a monovalent hydrocarbon group such as a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms or a linear, branched, or cyclic alkenyl group having 2 to 20 carbon atoms. These groups may contain a heteroatom such as oxygen, sulfur, nitrogen, and fluorine. RL34 and RL35, RL34 and RL36, and RL35 and RL36 may be bonded to form an aliphatic ring having 3 to 20 carbon atoms together with the carbon atoms to which these groups are bonded.
Illustrative examples of the tertiary alkyl group shown by the formula (A-3) include a tert-butyl group, a triethylcarbyl group, a 1-ethylnorbornyl group, a 1-methylcyclohexyl group, a 1-ethylcyclopentyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, and a tert-amyl group.
Other examples of the tertiary alkyl group include groups of the formulae (A-3)-1 to (A-3)-18.










In the formulae (A-3)-1 to (A-3)-18, each RL43 may be the same or different, and represents a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 20 carbon atoms, such as a phenyl group. RL44 and RL46 represent a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms. RL45 represents an aryl group having 6 to 20 carbon atoms, such as a phenyl group.
Furthermore, as shown in the formulae (A-3)-19 and (A-3)-20 below, the polymer may contain RL47 which represents a group with two or more valency such as an alkylene group and an arylene group to form intermolecular or intramolecular crosslinking. E1 represents an integer of 0 to 8, preferably 0 to 6.




The novolak resin having the repeating unit shown by the formula (1) or (2) may be a co-condensate of a monomer other than the above-described bisnaphthol derivative. Illustrative examples of the monomer usable in co-condensation include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-butyl-5-methylphenol, pyrogallol, thymol, isothymol, 4,4′-(9H-fluoren-9-ylidene)bisphenol, 2,2′-dimethyl-4,4′-(9H-fluoren-9-ylidene)bisphenol, 2,2′-diallyl-4,4′-(9H-fluoren-9-ylidene)bisphenol, 2,2′-difluoro-4,4′-(9H-fluoren-9-ylidene)bisphenol, 2,2′-diphenyl-4,4′-(9H-fluoren-9-ylidene)bisphenol, 2,2′-dimethoxy-4,4′-(9H-fluoren-9-ylidene)bisphenol, 2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 3,3,3′,3′-tetramethyl-2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 3,3,3′,3′,4,4′-hexamethyl-2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-5,5′-diol, 5,5′-dimethyl-3,3,3′,3′-tetramethyl-2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, 6-methoxy-2-naphthol, 3-methoxy-2-naphthol, 1,4-dimethoxynaphthalene, 1,5-dimethoxynaphthalene, 1,6-dimethoxynaphthalene, 1,7-dimethoxynaphthalene, 1,8-dimethoxynaphthalene, 2,3-dimethoxynaphthalene, 2,6-dimethoxynaphthalene, 2,7-dimethoxynaphthalene, methyl 3-hydroxy-naphthalene-2-carboxylate, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, 1,3-dimethylnaphthalene, 1,4-dimethylnaphthalene, 1,5-dimethylnaphthalene, 1,6-dimethylnaphthalene, 1,7-dimethylnaphthalene, 1,8-dimethylnaphthalene, 2,3-dimethylnaphthalene, 2,6-dimethylnaphthalene, 2,7-dimethylnaphthalene, 1-ethylnaphthalene, 2-ethylnaphthalene, 1-propylnaphthalene, 2-propylnaphthalene, 1-butylnaphthalene, 2-butylnaphthalene, 1-phenylnaphthalene, 1-cyclohexylnaphthalene, 1-cyclopentylnaphthalene, indene, hydroxyanthracene, acenaphthylene, acenaphthene, biphenyl, bisphenol, trisphenol, dicyclopentadiene, substituted or unsubstituted phenolphthalein, phenol red, cresolphthalein, cresol red, thymolphthalein, 2-fluorophenol, 3-fluorophenol, 4-fluorophenol, 4-trifluoromethylphenol, 2,3-difluorophenol, 2,4-difluorophenol, 2,5-difluorophenol, 2,6-difluorophenol, 3,4-difluorophenol, 3,5-difluorophenol, 2,3,4-trifluorophenol, 2,3,6-trifluorophenol, 3,4,5-trifluorophenol, 2-trifluoromethoxyphenol, 3-trifluoromethoxyphenol, 4-trifluoromethoxyphenol, 2-trifluoromethylthiophenol, 3-trifluoromethylthiophenol, 4-trifluoromethylthiophenol, 2,3-ditrifluorophenol, 2,4-ditrifluorophenol, 2,5-ditrifluorophenol, 2,6-ditrifluorophenol, 3,4-ditrifluorophenol, 3,5-ditrifluorophenol, pentafluorophenol, 3-trifluoromethylphenol, 2-trifluoromethylphenol, 4-(1,1,1,3,3,3-hexafluoro-2-propanol)phenol, 3-(1,1,1,3,3,3-hexafluoro-2-propanol)phenol, and 3,5-di(1,1,1,3,3,3-hexafluoro-2-propanol)phenol.
To synthesize the novolak resin having the repeating unit shown by the formula (1) or (2), optional monomers and aldehyde are added to the above-described substituted or unsubstituted bisnaphthol derivative and polymerized to form a novolak. Forming a novolak increases the molecular weight, thus enabling the inhibition of generation of outgas and particles due to low molecular weight components at baking.
Examples of the aldehyde usable in synthesis of the novolak resins having the repeating unit shown by the formula (1) or (2) include formaldehyde, trioxane, paraformaldehyde, benzaldehyde, methoxybenzaldehyde, phenylbenzaldehyde, tritylbenzaldehyde, cyclohexylbenzaldehyde, cyclopentylbenzaldehyde, tert-butylbenzaldehyde, naphthalenealdehyde, hydroxynaphthalenealdehyde, anthracenealdehyde, fluorenealdehyde, pyrenealdehyde, methoxynaphthalenealdehyde, dimethoxynaphthalenealdehyde, acetaldehyde, propylaldehyde, phenylacetaldehyde, naphthaleneacetaldehyde, substituted or unsubstituted carboxylnaphthaleneacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, p-n-butylbenzaldehyde, furfural, furancarboxaldehyde, and thiophenealdehyde. Among them, formaldehyde is particularly preferable.
The aldehydes can be used alone or in combination of two or more kinds. The amount of the aldehyde to be used is preferably 0.2 to 5 mol, more preferably 0.5 to 2 mol with respect to 1 mol of the substituted or unsubstituted bisnaphthol derivative.
A catalyst may be used in condensation reaction of the bisnaphthol derivative with the aldehyde. Illustrative examples thereof include acid catalysts such as hydrochloric acid, nitric acid, sulfuric acid, formic acid, oxalic acid, acetic acid, methanesulfonic acid, camphor sulfonic acid, tosic acid, and trifluoromethane sulfonic acid. The amount of the acid catalyst to be used is preferably in the range of 1×10−5 to 5×10−1 mol with respect to 1 mol of the bisnaphthol derivative.
The novolak resins having the repeating unit shown by the formula (1) or (2) preferably have a weight average molecular weight in the range of 400 to 20,000, more preferably 500 to 10,000, particularly preferably 600 to 10,000. A resin having smaller molecular weight is excellent in filling property, but easy to generate outgas in baking. Thus, it is preferable to optimize the molecular weight in view of filling property and generation of outgas.
To achieve both filling property and outgas reduction, the novolak resin having the repeating unit shown by the formula (2) is preferable contained in amount of 0.1 to 50 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1). For the same purpose, the bisnaphthol derivative shown by the formula (3) is preferably contained in amount of 0 to 50 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1).
Furthermore, the inventive resist under layer film composition preferably contains the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3) in a total amount of 5 to 100 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1). Such a ratio enables the reduction in outgas by a resin layer of the novolak resin having the repeating unit shown by the formula (1) and the improvement in filling property by the bisnaphthol derivative shown by the formula (3) to be achieved with particularly good balance.
When the novolak resin having the repeating unit shown by the formula (1) or (2) is synthesized, the reaction solution may contain monomers such as a substituted or unsubstituted bisnaphthol derivative that is unpolymerized and low molecular weight components such as dimer and trimer. Since a bisnaphthol derivative has larger molecular weight than a naphthol derivative, a bisnaphthol derivative is more difficult to become an outgas component than a naphthol derivative. However, large amount of the unpolymerized monomers and the low molecular weight components can cause outgas. Therefore, these components are preferably removed as much as possible to achieve both filling property and outgas reduction. In the case that monomer components are added to improve filling property, it is preferable to add additional monomer components in desired amount after the unpolymerized monomers and the low molecular weight components are removed as mentioned above.
The inventive resist under layer film composition contains the novolak resin having the repeating unit shown by the formula (1) and either or both of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3). In addition to these novolak resins, other resin may be blended to the composition. Examples of the blendable resin include novolak resins obtained by reaction of aldehyde with 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-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-butyl-5-methylphenol, pyrogallol, thymol, isothymol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, dihydroxynaphthalene such as 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene, phenolphthalein, phenol red, cresolphthalein, cresol red, thymolphthalein, methyl 3-hydroxynaphthalene-2-carboxylate, indene, hydroxyindene, benzofuran, hydroxyanthracene, acenaphthylene, biphenyl, bisphenol, or trisphenol. Other examples include resins obtained by co-condensation of a phenol compound with dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, norbornadiene, 5-vinylnorborna-2-ene, α-pinene, β-pinene, or limonene, without aldehyde.
Furthermore, as a monomer component other than the bisnaphthol derivative shown by the formula (3), a compound selected from hydroxystyrene, alkoxystyrene, hydroxyvinylnaphthalene, alkoxyvinylnaphthalene, (meth)acrylate, vinylether, maleic anhydride, and itaconic anhydride may be added. A compound such as substituted or unsubstituted naphthol may also be added.
The inventive resist under layer film composition may further contain a high-carbon resin. Examples of the resin include resins used in a resist under layer film composition disclosed in Japanese Patent Laid-Open Publication No. 2004-205658, No. 2004-205676, No. 2004-205685, No. 2004-271838, No. 2004-354554, No. 2005-010431, No. 2005-049810, No. 2005-114921, No. 2005-128509, No. 2005-250434, No. 2006-053543, No. 2006-227391, No. 2006-259249, No. 2006-259482, No. 2006-285095, No. 2006-293207, No. 2006-293298, No. 2007-140461, No. 2007-171895, No. 2007-199653, No. 2007-316282, No. 2008-026600, No. 2008-065303, No. 2008-096684, No. 2008-257188, No. 2010-160189, No. 2010-134437, No. 2010-170013, No. 2010-271654, No. 2008-116677, and No. 2008-145539.
The novolak resin having the repeating unit shown by the formula (1) in the inventive under layer film composition preferably contains one or more groups selected from the formulae (4)-1 to (4)-5 as R1 and/or R2 in the formula (1),




wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R0 represents a hydrogen atom, a methyl group, an acetyl group, or a trifluoroacetyl group; Rf represents a fluorine atom, a linear, branched, or cyclic alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon, an aralkyl group having 7 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, in which these groups contain at least one fluorine atom and may further contain a hydroxyl group or an alkoxy group; R22 represents a hydrogen atom, a methyl group, or an ethyl group; and R23 and R24 represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

When such groups are contained, the amount of outgas generated from the resist under layer film composition can be further reduced.
Illustrative examples of the groups shown by the formulae (4)-1 to (4)-5 include the following groups.




























In the novolak resin having the repeating unit shown by the formula (1), preferably 10% or more, more preferably 20% or more, particularly preferably 30% or more of the total of R1 and R2 in the formula (1) are groups shown by the formula (4)-1 to (4)-5. The novolak resin having the repeating unit shown by the formula (1) may contain various fluorine-containing groups shown by the formula (4)-1 to (4)-5.
Examples of the method for synthesizing the novolak resin having the repeating unit shown by the formula (1) include a method in which a monomer of the bisnaphthol derivative wherein R1 and/or R2 is a fluorine-containing group reacts with an aldehyde to form a novolak resin; a method in which a monomer of the bisnaphthol derivative wherein R1 and/or R2 is a hydrogen atom reacts with an aldehyde to form a novolak resin, and a fluorine-containing group is added to the obtained novolak resin; and a method in which a hydrogen atom of a hydroxyl group in a novolak resin is substituted with a fluorine-containing group.
Examples of the method for adding a fluorine-containing group to a novolak resin include an addition reaction of a fluorine-containing compound having a carbon-carbon double bond with a hydroxyl group of a novolak resin. Examples of the method for substituting a hydrogen atom of a hydroxyl group in a novolak resin with a fluorine-containing group include a method which uses an epoxy compound, an acid anhydride, an acid chloride or the like containing one or more fluorine atoms for substitution.
(Organic Solvent)
The inventive resist under layer film composition may further contain an organic solvent. The organic solvent usable in the inventive resist under layer film composition is not limited so long as it can dissolve a base resin of the above-described novolak resin or other resin, monomer components, and additives such as an acid generator and a crosslinking agent described later. Specifically, solvents disclosed in paragraphs (0091) and (0092) of Japanese Patent Laid-Open Publication No. 2007-199653 may be added.
(Crosslinking Agent)
The resist under layer film requires characteristics that when a silicon-containing middle layer film composition or a resist upper layer film composition is dispensed to the resist under layer film, the resist under layer film does not dissolve in the silicon-containing middle layer film composition or the resist upper layer film composition and does not mix with the silicon-containing middle layer film or the resist upper layer film. Therefore, a crosslinking agent is preferably added to the inventive resist under layer film composition to promote crosslinking by baking after the application.
Examples of the crosslinking agent usable in the present invention include a melamine compound, a guanamine compound, a glycoluril compound, a urea compound, an epoxy compound, an isocyanate compound, or an azide compound that is substituted with at least one group selected from a methylol group, an alkoxymethyl group, and acyloxymethyl group; and a compound having a double bond such as an alkenyl ether group. These compounds may be used as an additive, or may be introduced as a pendant group into a side chain of the polymer. A compound containing a hydroxyl group may also be used as the crosslinking agent.
Illustrative examples of the crosslinking agent include epoxy compounds such as tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether; melamine compounds such as hexamethylol melamine, hexamethoxymethyl melamine, a hexamethylol melamine compound in which 1 to 6 methylol groups are methoxymethylated, a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, and a hexamethylol melamine compound in which 1 to 6 methylol groups are acyloxymethylated, and a mixture thereof; guanamine compounds such as tetramethylol guanamine, tetramethoxymethyl guanamine, a tetramethylol guanamine compound in which 1 to 4 methylol groups are methoxymethylated, a mixture thereof, tetramethoxyethyl guanamine, tetraacyloxy guanamine, a tetramethylol guanamine compound in which 1 to 4 methylol groups are acyloxymethylated, and a mixture thereof; glycoluril compounds such as tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a tetramethylol glycoluril compound in which 1 to 4 methylol groups are methoxymethylated, a mixture thereof, a tetramethylol glycoluril compound in which 1 to 4 methylol groups are acyloxymethylated, and a mixture thereof; urea compounds such as tetramethylol urea, tetramethoxymethyl urea, a tetramethylol urea compound in which 1 to 4 methylol groups are methoxymethylated, a mixture thereof, and tetramethoxyethyl urea; isocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate; and azide compounds such as 1,1′-biphenyl-4,4′-bisazide, 4,4′-methylidene bisazide, and 4,4′-oxybisazide.
As the crosslinking agent for forming crosslinking by an acetal group, there may be mentioned a compound having multiple enolether groups within the molecule. Examples of the crosslinking agent having at least two enolether groups within the molecule include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, ethylene glycol dipropenyl ether, triethylene glycol dipropenyl ether, 1,2-propanediol dipropenyl ether, 1,4-buthanedisol dipropenyl ether, tetramethylene glycol dipropenyl ether, neopentyl glycol dipropenyl ether, trimethylol propane tripropenyl ether, hexanediol dipropenyl ether, 1,4-cyclohexanediol dipropenyl ether, pentaerythritol tripropenyl ether, pentaerythritol tetrapropenyl ether, sorbitol tetrapropenyl ether, and sorbitol pentapropenyl ether.
In addition, following compounds may be mentioned as the crosslinking agent of the compound having multiple enolether groups within the molecule.







An enolether group is linked with an hydroxyl group through an acetal bond by heat. Thus, addition of the compound having multiple enolether groups within the molecule promotes thermal crosslinking by acetal groups.
In addition, a crosslinking agent containing an acid-labile tertiary ester group having two or more oxirane within the molecule may also be added. Illustrative examples of the crosslinking agent include compounds disclosed in Japanese Patent Laid-Open Publication No. 2006-096848. When such a crosslinking agent is used, the oxirane is crosslinked by heat and the tertiary ester portion is decomposed by acid, as described in Japanese Patent Laid-Open Publication No. 2001-226430.
The inventive resist under layer film composition can be crosslinked by heating at 300° C. or higher after spin coating even without containing a crosslinking agent as mentioned above. In this case, polymers are linked by oxidative coupling reaction.
(Acid Generator)
In addition, an acid generator may be added to the inventive resist under layer film composition to further promote crosslinking reaction by heat. The acid generator includes one capable of generating an acid by thermal decomposition and one capable of generating an acid by light irradiation, and any acid generator can be added. Specifically, materials disclosed in paragraphs (0061) to (0085) of Japanese Patent Laid-Open Publication No. 2007-199653 may be mentioned.
When the inventive resist under layer film composition as described above is used, a resin layer of the novolak resin having the repeating unit shown by the formula (1) with fluorine atoms in a prescribed amount or more is formed on the resist under layer film surface. This fluorine-containing layer inhibits generation of outgas even when the resist under layer film composition is baked at high temperature. Moreover, by adding the monomer component shown by the formula (3) to the resist under layer film composition, the property of filling gaps of a substrate can be improved while inhibiting generation of outgas.
<Patterning Process>
Furthermore, the present invention provides a patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the above-described resist under layer film composition; forming a silicon-containing middle layer film on the resist under layer film by using a silicon-containing middle layer film composition; forming a resist upper layer film on the silicon-containing middle layer film by using a resist upper layer film composition; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the silicon-containing middle layer film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the silicon-containing resist middle layer film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.
Hereinafter, examples of the inventive patterning process will be described with reference to drawings, but the present invention is not limited thereto.
FIG. 1A to 1F show an example of the inventive patterning process by 3-layer process using a silicon-containing middle layer film. In the patterning process shown in FIG. 1A to 1F, first, (A) the inventive resist under layer film composition is applied onto a layer to be processed 2 on a substrate 1 to form a resist under layer film 3, a silicon-containing middle layer film composition is applied onto the resist under layer film 3 to form a silicon-containing middle layer film 4, and a resist upper layer film composition is applied onto the silicon-containing middle layer film 4 to form a resist upper layer film 5. Then, (B) a pattern circuit region 6 of the resist upper layer film 5 is exposed to light, and (C) development is performed to form a resist pattern in the resist upper layer film 5 (in the case of positive resist). (D) The pattern is transferred to the silicon-containing middle layer film 4 by etching using the resist upper layer film 5 having the formed resist pattern as a mask. (E) The pattern is transferred to the resist under layer film 3 by etching using the silicon-containing middle layer film 4 having the transferred pattern as a mask. (F) The pattern is formed in the layer to be processed 2 by etching using the resist under layer film 3 having the transferred pattern as a mask.
[Substrate to be Processed]
The substrate to be processed may be, but is not limited to, a substrate on which a layer to be processed is formed. The substrate is not limited, and a material such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, and Al, and a different material from the layer to be processed is preferably used. The layer to be processed is preferably made of Si, SiO2, SiON, SiN, p-Si, α-Si, W, W—Si, Al, Cu, Al—Si, or the like; and various low dielectric constant (low-k) films, etching stopper films thereof, and a substrate with gaps for Fin-FET are preferably used. The layer to be processed is preferably formed with a thickness of 10 to 10,000 nm, particularly 20 to 5,000 nm.
A hard mask for processing the substrate may be formed between the substrate to be processed and the resist under layer film. When the substrate to be processed is a SiO2 insulator film substrate, SiN, SiON, p-Si, α-Si, W, W—Si, amorphous carbon or the like is used as the hard mask. When the substrate to be processed is a gate electrode such as p-Si, W—Si, and Al—Si, SiO2, SiN, SiON or the like is used.
On the resist under layer film formed from the inventive resist under layer film composition, a resist upper layer film may be formed. Alternatively, a tri-layer process in which a middle layer film containing an element selected from silicon, titanium, zirconium, and hafnium is formed between a resist upper layer film and the resist under layer film is also preferably used. The most preferable element contained in the middle layer film for the tri-layer is silicon.
[Silicon-Containing Middle Layer Film]
The silicon-containing middle layer film composition may include, though not limited to, a silsesquioxane-based material having absorption at the exposure wavelength as disclosed in Japanese Patent Laid-Open Publication No. 2007-302873. The silicon-containing middle layer film may be formed by spin coating. After spin coating, the silicon-containing middle layer film composition is baked at 150 to 300° C. to form a silicon-containing middle layer film composed of a silicon oxide film.
The best optical constants (n- and k-values) of the silicon-containing middle layer film to be used in the tri-layer process for antireflection effect is as follows: the n-value is 1.5 to 1.9; the k-value is 0.15 to 0.3; the film thickness is 20 to 130 nm. Moreover, the best resist under layer film has a n-value of 1.3 to 1.8, a k-value of 0.2 to 0.8, and a film thickness of 50 nm or more.
[Resist Upper Layer Film]
The resist upper layer film composition may contain, though not limited to, a known base polymer mainly consisting of hydrocarbon, as disclosed in Japanese Patent Laid-Open Publication No. H09-073173 and No. 2000-336121. The thickness of the resist upper layer film is preferably, but not limited to, 20 to 500 nm, particularly 30 to 400 nm.
The spin coating method is suitable to form the resist upper layer film from the resist upper layer film composition, as in the case that the resist under layer film is formed. After the resist upper layer film is formed by spin coating or other method, pre-baking is performed preferably at 80 to 180° C. for 10 to 300 seconds.
When an inorganic hard mask intermediate film is formed instead of the silicon-containing middle layer film, an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film may be formed between the resist under layer film and the resist upper layer film.
[Inorganic Hard Mask Intermediate Film]
The inorganic hard mask intermediate film composition is not limited. An inorganic hard mask intermediate film containing an element selected from metals such as silicon, titanium, zirconium, and hafnium may be used. In particular, as to the titanium-containing intermediate film, materials disclosed in Japanese Patent Laid-Open Publication No. 2014-178602 may be used. The tri-layer process can be done by forming an inorganic hard mask intermediate film on a resist under layer film and forming a resist upper layer film thereon. In particular, p-Si, SiN, SiON, SiC, TiN, TiO2, TiC, ZrO2, and HfO2 are preferable as the inorganic hard mask intermediate film material. The inorganic hard mask intermediate film can be formed by, for example, the CVD method, the ALD method, or the sputtering method.
In the case of a 4-layer resist film in which an organic antireflection film is formed on the inorganic hard mask intermediate film, an organic antireflection film composition may be applied onto the inorganic hard mask intermediate film to form an organic antireflection film. This case is called 4-layer process.
[Organic Antireflection Film]
The organic antireflection film composition is not limited, and any known material can be used.
In the case of a 5-layer resist film in which a hydrocarbon film is formed and an silicon-containing middle layer film is then formed thereon, a hydrocarbon film is formed on the inorganic hard mask intermediate film from a hydrocarbon film composition by spin coating, and a silicon-containing middle layer film is formed thereon from a silicon-containing middle layer film composition. This case is called 5-layer process.
The hydrocarbon film composition is not limited, and any known materials can be used.
[Pattern Formation]
(3-Layer Process)
A method for forming a resist under layer film by using the inventive resist under layer film composition will now be described. The film can be formed on a substrate by spin coating or other method, in the same manner as in the conventional method for forming a photoresist film. The resist under layer film composition is applied onto the above-described substrate to be processed by spin coating or other method to form a resist under layer film. Then, baking is preferably performed to evaporate the organic solvent, prevent mixing with a resist upper layer film, or promote crosslinking reaction. The baking temperature is preferably at 80 to 1,000° C. for 10 to 300 seconds. The thickness of the resist under layer film is appropriately determined, and it is preferred to set 5 to 100,000 nm, particularly 10 to 50,000 nm. The above range of thickness provides high antireflection effect.
The most common baking method is performed on a hot plate. The baking may also be performed by irradiating with infrared rays. A hot plate may be used for baking at a high temperature of 400° C. or higher, while a furnace which can heat several hundred wafers in a batch manner has an advantage of throughput.
In the case of the 3-layer process, as shown in FIG. 1A, a resist under layer film 3 is formed on a layer to be processed 2 laminated on a substrate 1, a silicon-containing middle layer film 4 is formed thereon, and a resist upper layer film 5 is formed thereon.
In addition, a resist top coat may be formed on the resist upper layer film. The resist top coat is often formed for the purpose of preventing elution of additives such as an acid generator from the resist upper layer film and improving water-sliding property in the liquid immersion exposure. The resist top coat may have antireflection function. The resist top coat can be classified into water-soluble one and water-insoluble one. The water-insoluble resist top coat is further classified into a material that is soluble in an alkali developer and a material that is insoluble in an alkali developer and removable with an organic solvent. The former is preferable because of process advantage that the top coat can be removed at the time of development of the resist. In the case of forming a negative pattern by organic solvent development, the latter solvent-removable top coat can be removed at the time of development. When the top coat is soluble in an alkali developer, a solution in which a polymer having α-trifluoromethylhydroxyl group is dissolved in a higher alcohol having 4 or more carbon atoms or an ether compound having 8 to 12 carbon atoms is used.
As to the method for forming the resist top coat, a top coat composition is applied onto the resist upper layer film by spin coating after prebaking. The film thickness of the resist top coat is preferably 10 to 200 nm. After drying or liquid immersion exposure, post exposure baking (PEB) is performed, followed by development with an alkali developer for 10 to 300 seconds. Usually, a 2.38 mass % tetramethylammonium hydroxide aqueous solution is widely used as the alkali developer. When a resist top coat soluble in the developer is used, removal of the resist top coat and development of the resist upper layer film can be performed at the same time.
A resist pattern of the resist upper layer film can be formed according to the conventional method. A resist pattern can be obtained by exposure of a pattern circuit region of the resist upper layer film, PEB, and development. When a silicon-containing middle layer film which contains a polymer having silicon-containing acid-labile pendants and an acid generator is used, the resist pattern and a pattern of the silicon-containing middle layer film can be obtained at the same time by exposure and development.
Here, if water remains on the resist upper layer film before PEB, the water absorbs acid in the resist upper layer film during PEB, impeding pattern formation. To fully remove water on the resist top coat before PEB, water on the film is preferably dried or recovered by suitable means, for example, spin drying prior to PEB, purging of the film surface with dry air or nitrogen, or optimizing the water recovery nozzle configuration or process on a stage after the exposure.
First, a pattern circuit region 6 of the resist upper layer film 5 is exposed (FIG. 1B), and PEB and development are carried out to form a resist pattern in the resist upper layer film 5 (FIG. 1C). By using the obtained resist patter as a mask, the silicon-containing middle layer film 4 is etched with CF-based gas to transfer the pattern to the silicon-containing middle layer film 4 (FIG. 1D).
The development is carried out by, for example, the puddle method or the dip method with an alkali aqueous solution. In particular, the puddle method with a 2.38 mass % tetramethylammonium hydroxide aqueous solution is preferable. The film is treated with an developer at room temperature for 10 seconds to 300 seconds, then rinsed with pure water and dried by spin drying, nitrogen blowing or other method. The exposed part is dissolved by alkali development in the case of positive resist, or insolubilized in the case of negative resist.
A negative pattern can also be formed by organic solvent development. The solvent to be used in this development is one or more solvents selected from 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutylketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxy-isobutyrate, ethyl 2-hydroxy-isobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate.
Then, the pattern is transferred to the resist under layer film 3 by dry etching with oxygen plasma or the like (FIG. 1E) using the resist pattern and the pattern of the silicon-containing middle layer film as a mask. The resist under layer film formed from the inventive resist under layer film composition is preferably dry etched with an etching gas containing an oxygen gas or a hydrogen gas. In addition to the oxygen gas or hydrogen gas, an inert gas such as He and Ar or a gas such as CO, CO2, NH3, SO2, N2, and NO2 may be added.
Moreover, it is preferred that the resist upper layer film composition do not contain a polymer having a silicon atom, and the etching of the resist under layer film be performed with an etching gas containing an oxygen gas or a hydrogen gas. Use of such an etching gas enables the removal of the resist upper layer film and the etching of the resist under layer film to be performed at the same time.
Once the pattern of the silicon-containing middle layer film is removed, the layer to be processed 2 is etched by using the pattern of the resist under layer film as a mask to form the pattern (FIG. 1F). Here, when the layer to be processed 2 is made of SiO2 or SiN, an etching gas containing fluorocarbon-based gas is preferable, and when the layer is made of polysilicon (p-Si), Al, or W, an etching gas containing chlorine-based gas or bromine-based gas is preferable. If ions are implanted, the substrate to be processed does not necessarily need to be processed, and the ions are implanted by using the pattern of the resist under layer film as a mask. Before or after ion implantation, the silicon-containing middle layer film and the resist under layer film are removed. This removal may be performed by dry stripping with CF gas or O2 gas or wet stripping with water containing sulfuric acid and hydrogen peroxide or water containing ammonia and hydrogen peroxide.
When an inorganic hard mask intermediate film is formed instead of the silicon-containing middle layer film, etching of the inorganic hard mask intermediate film may be carried out according to the conventional method.
In the case of 4-layer process, etching of the organic antireflection film may be carried out according to the conventional method. The etching of the organic antireflection film and the inorganic hard mask intermediate film may be carried out successively, or after the organic antireflection film is etched alone, an etching apparatus may be changed to etch the inorganic hard mask intermediate film.
In the case of 5-layer process, etching of the hydrocarbon film may be carried out according to the conventional method.
As mentioned above, the inventive patterning process using the inventive resist under layer film composition allows a substrate to be sufficiently embedded, prevents generation of outgas, and thus significantly reduces defects at fine processing in the manufacturing process of a semiconductor apparatus and the like. Accordingly, the resist under layer film composition and the patterning process of the present invention are especially suitable for manufacturing a three-dimension device such as Fin-FET, which requires filling a trench pattern having narrow pitch and inhibiting generation of outgas during baking of the resist under layer film that may cause defects.
EXAMPLES
Hereinafter, the present invention will be specifically explained with reference to examples and comparative examples, but the present invention is not limited thereto.
Synthesis of Novolak Resin Having Repeating Unit Shown by Formula (2)
Synthesis Example 1-1
45 g of 6,6′-(9H-fluoren-9,9-diyl)di(2-naphthol), 120 g of a 37 mass % formalin aqueous solution, 5 g of oxalic acid, and 50 g of dioxane were mixed and stirred at 100° C. for 24 hours. After reaction, the reaction product was dissolved in 500 mL of methylisobutyl ketone, and the catalyst and metal impurities were removed by sufficiently washing with water. Then, the pressure was reduced to 2 mmHg at 150° C., and moisture and the solvent were thus removed under reduced pressure to obtain Novolak resin 2-1 shown below.
Novolak Resin 2-1
Molecular weight (Mw)=3,100
Dispersity (Mw/Mn)=3.88




Synthesis Example 1-2
45 g of α-naphtholphthalein, 120 g of a 37 mass % formalin aqueous solution, 5 g of oxalic acid, and 50 g of dioxane were mixed, and Novolak resin 2-2 shown below was obtained in the same manner as in Synthesis example 1-1.
Novolak Resin 2-2
Molecular weight (Mw)=2,100
Dispersity (Mw/Mn)=3.67




Synthesis Example 1-3
45 g of naphthofluorescein, 120 g of a 37 mass % formalin aqueous solution, 5 g of oxalic acid, and 50 g of dioxane were mixed, and Novolak resin 2-3 shown below was obtained in the same manner as in Synthesis example 1-1.
Novolak Resin 2-3
Molecular weight (Mw)=2,600
Dispersity (Mw/Mn)=3.55




Synthesis Example 1-4
45 g of 6,6′-(9H-fluoren-9,9-diyl)di(2-naphthol), 60 g of a 37 mass % formalin aqueous solution, 5 g of oxalic acid, and 50 g of dioxane were mixed and stirred at 80° C. for 24 hours. After reaction, the reaction product was dissolved in 500 mL of methylisobutyl ketone, and the catalyst and metal impurities were removed by sufficiently washing with water. Then, the pressure was reduced to 2 mmHg at 150° C., and moisture and the solvent were thus removed under reduced pressure to obtain Novolak resin 2-4 shown below.
Novolak Resin 2-4
Molecular weight (Mw)=1,100
Dispersity (Mw/Mn)=3.86




Synthesis of Novolak Resin Having Repeating Unit Shown by Formula (1)
Synthesis Example 2-1
A mixture of 4.6 g of Novolak resin 2-1, 2.2 g of 4,5-epoxy-1,1,1-trifluoropentane, 40 g of 1-methoxy-2-propanol, 0.2 g of water containing 25 mass % caustic soda was stirred at room temperature for 24 hours. The mixture was diluted with ethyl acetate and washed with dilute nitric acid and ultrapure water, and the solvent was distilled off under reduced pressure to obtain 6.8 g of Novolak resin 1-1 shown below. The obtained Novolak resin 1-1 was analyzed by 13C, 1H-nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC), giving the following result.
Novolak Resin 1-1
Molecular weight (Mw)=4,000
Dispersity (Mw/Mn)=3.95




Synthesis Example 2-2
A mixture of 4.6 g of Novolak resin 2-1, 4.3 g of 3,3,3-trifluoropropionic anhydride, 30 g of ethyl acetate, 0.2 g of methanesulfonic acid was stirred at 70° C. for 24 hours. After cooling, the mixture was washed with dilute ammonia water and ultrapure water, and the solvent was distilled off under reduced pressure to obtain 6.6 g of Novolak resin 1-2 shown below. The obtained Novolak resin 1-2 was analyzed as above, giving the following result.
Novolak Resin 1-2
Molecular weight (Mw)=3,600
Dispersity (Mw/Mn)=3.90




Synthesis Example 2-3
A mixture of 4.6 g of Novolak resin 2-1, 5.0 g of trifluoromethanesulfinic anhydride, 40 g of N,N-dimethylformamide, and 3.0 g of triethylamine was stirred at 70° C. for 24 hours. After cooling, the mixture was diluted with ethyl acetate and washed with ultrapure water, and the solvent was distilled off under reduced pressure to obtain 6.9 g of Novolak resin 1-3 shown below. The obtained Novolak resin 1-3 was analyzed as above, giving the following result.
Novolak Resin 1-3
Molecular weight (Mw)=3,400
Dispersity (Mw/Mn)=3.89




Synthesis Example 2-4
10.2 g of Novolak resin 1-4 shown below was obtained from a mixture of 4.6 g of Novolak resin 2-1, 6.4 g of nonafluorobutanesulfonic acid chloride, 40 g of N,N-dimethylformamide, and 3.0 g of triethylamine in the same manner as in Synthesis example 2-1. The obtained Novolak resin 1-4 was analyzed as above, giving the following result.
Novolak Resin 1-4
Molecular weight (Mw)=4,200
Dispersity (Mw/Mn)=4.25




Synthesis Example 2-5
4.0 g of Novolak resin 2-1 was dissolved in 40 mL of tetrahydrofuran, followed by adding 0.01 g of methanesulfonic acid and 1.7 g of 2,2,2-trifluoroethylvinyl ether to react the mixture at room temperature for 1 hour. Then, 0.25 g of 30 mass % ammonia water was added to quench the reaction. The obtained reaction solution was poured into 1 L of acetic acid water for crystallization and precipitation. A white solid obtained by washing twice with water and filtration was dried under reduced pressure at 40° C. to obtain a white polymer shown below. The obtained polymer named Novolak resin 1-5 was analyzed as above, giving the following result.
Novolak Resin 1-5
Molecular weight (Mw)=3,800
Dispersity (Mw/Mn)=4.00




Examples 1-1 to 1-10, Comparative Examples 1-1 and 1-2
Preparation of Resist Under Layer Film Composition
Novolak resins 1-1 to 1-5, Novolak resins 2-1 to 2-4, and Monomers 1 to 6 shown below were dissolved in an organic solvent containing 0.1 mass % of FC-4430 (available from Sumitomo 3M Ltd.) with the proportion shown in Table 1. The solution was filtered through a 0.1-μm filter made of a fluorine resin to prepare resist under layer film compositions (Under layer film compositions 1 to 10, Comparative under layer film compositions 1 and 2).
Monomers 1 to 6







(Refractive Index Measurement)

The resist under layer film compositions (Under layer film compositions 1 to 10, Comparative under layer film compositions 1 and 2) thus prepared were each applied onto a silicon (Si) substrate, and baked at 350° C. for 60 seconds to form a resist under layer film with a thickness of 100 nm. After formation of the resist under layer film, refractive index (n, k) at 193 nm wavelength was measured by a spectroscopic ellipsometer with a variable incident light angle (VASE) manufactured by J. A. Woollam Co., Inc. The result is given in Table 1.













TABLE 1









Organic




Resist under
Polymer 1
Polymer 2
Additive
solvent


layer film
(parts by
(parts by
(parts by
(parts by
n-
k-


composition
mass)
mass)
mass)
mass)
value
value





















Under layer
Novolak resin
Novolak resin
Monomer 1
PGMEA
1.38
0.46


film
1-1 (7)
2-1 (43)
(50)
(2500)


composition 1


Under layer
Novolak resin
Novolak resin
Monomer 1
PGMEA
1.40
0.45


film
1-2 (7)
2-1 (43)
(50)
(2500)


composition 2


Under layer
Novolak resin
Novolak resin
Monomer 1
PGMEA
1.41
0.46


film
1-3 (7)
2-1 (43)
(50)
(2500)


composition 3


Under layer
Novolak resin
Novolak resin
Monomer 1
PGMEA
1.37
0.45


film
1-4 (7)
2-1 (43)
(50)
(2500)


composition 4


Under layer
Novolak resin
Novolak resin
Monomer 2
PGMEA
1.44
0.43


film
1-5 (15)
2-2 (25)
(60)
(2500)


composition 5


Under layer
Novolak resin
Novolak resin
Monomer 3
PGMEA
1.44
0.42


film
1-1 (20)
2-3 (20)
(60)
(2500)


composition 6


Under layer
Novolak resin
Novolak resin
—
PGMEA
1.40
0.45


film
1-1 (15)
2-4 (85)

(2500)


composition 7


Under layer
Novolak resin
—
Monomer 4
PGMEA
1.38
0.46


film
1-1 (20)

(80)
(2500)


composition 8


Under layer
Novolak resin
—
Monomer 5
PGMEA
1.40
0.45


film
1-2 (7)

(80)
(2500)


composition 9


Under layer
Novolak resin
—
Monomer 6
PGMEA
1.41
0.45


film
1-2 (7)

(30)
(2500)


composition


Monomer 1


10


(50)


Comparative
—
Novolak resin
Monomer 1
PGMEA
1.40
0.48


under layer

2-1 (50)
(50)
(4000)


film


composition 1


Comparative
—
Novolak resin
—
PGMEA
1.39
0.49


under layer

2-1 (100)

(4000)


film


composition 2





PGMEA: propylene glycol monomethyl ether acetate






(Sublimate Measurement)

The prepared resist under layer film compositions (Under layer film compositions 1 to 10, Comparative under layer film compositions 1 and 2) were each applied onto a Si substrate, and baked under conditions shown in Table 2. The number of particles with a size of 0.3 μm or 0.5 μm generated in a hot plate oven under baking was measured with a particle counter KR-11A, manufactured by RION Co., Ltd. The result is given in Table 2.












TABLE 2







Resist under
Baking
0.3-μm
0.5-μm



layer film
temperature
particles
particles



composition
(° C.)
(number)
(number)




















Example 1-1
Under layer film
350
15
2



composition 1


Example 1-2
Under layer film
350
12
1



composition 2


Example 1-3
Under layer film
350
16
1



composition 3


Example 1-4
Under layer film
320
6
0



composition 4


Example 1-5
Under layer film
320
13
2



composition 5


Example 1-6
Under layer film
360
11
2



composition 6


Example 1-7
Under layer film
400
5
1



composition 7


Example 1-8
Under layer film
350
19
6



composition 8


Example 1-9
Under layer film
350
21
5



composition 9


Example 1-10
Under layer film
350
24
7



composition 10


Comparative
Comparative
350
102
29


example 1-1
under layer film



composition 1


Comparative
Comparative
350
25
8


example 1-2
under layer film



composition 2









The result shows that Under layer film compositions 1 to 10 and Comparative under layer film composition 2 caused less particles at baking than Comparative under layer film composition 1. Thus, it was revealed that these compositions reduced generation of outgas and hardly contaminated an oven for baking. Moreover, it was also revealed that all under layer film compositions had adequate heat resistance.
(Evaluation of Filling Property on Substrate Having Gaps)
Examples 2-1 to 2-10, Comparative Examples 2-1 and 2-2
A Si substrate on which a SiO2 film with a thickness of 500 nm having a dense hole pattern with a size of 160 nm and a pitch of 320 nm has been formed was used as a substrate having gaps. The prepared resist under layer film compositions (Under layer film compositions 1 to 10, Comparative under layer film compositions 1 and 2) were each applied onto the SiO2 film of the substrate having gaps under a condition where a film 95 nm thick can be formed on a flat Si substrate. Then, the wafer was cut to observe whether the bottoms of the holes were filled with the resist under layer film composition by a scanning electron microscope (SEM). The result is given in Table 3.











TABLE 3








Baking




Resist under layer
temperature
Filling state of hole



film composition
(° C.)
pattern



















Example 2-1
Under layer film
350
Under layer film filled



composition 1

the bottoms of holes,





and no void occurred


Example 2-2
Under layer film
350
Under layer film filled



composition 2

the bottoms of holes,





and no void occurred


Example 2-3
Under layer film
350
Under layer film filled



composition 3

the bottoms of holes,





and no void occurred


Example 2-4
Under layer film
320
Under layer film filled



composition 4

the bottoms of holes,





and no void occurred


Example 2-5
Under layer film
320
Under layer film filled



composition 5

the bottoms of holes,





and no void occurred


Example 2-6
Under layer film
360
Under layer film filled



composition 6

the bottoms of holes,





and no void occurred


Example 2-7
Under layer film
400
Under layer film filled



composition 7

the bottoms of holes,





and no void occurred


Example 2-8
Under layer film
360
Under layer film filled



composition 8

the bottoms of holes,





and no void occurred


Example 2-9
Under layer film
360
Under layer film filled



composition 9

the bottoms of holes,





and no void occurred


Example 2-10
Under layer film
360
Under layer film filled



composition 10

the bottoms of holes,





and no void occurred


Comparative
Comparative
350
Under layer film filled


example 2-1
under layer film

the bottoms of holes,



composition 1

and no void occurred


Comparative
Comparative
350
Voids occurred in the


example 2-2
under layer film

bottoms of holes



composition 2









The result of Table 3 shows that Under layer film compositions 1 to 10 had good filling property even in a substrate having gaps with high aspect ratio, and the combination with Table 2 indicates that these compositions inhibited generation of outgas. By contrast, Comparative under layer film compositions 1 and 2 could not accomplish both the achievement of filling property and the reduction in outgas.
Examples 3-1 to 3-10, Comparative Examples 3-1 and 3-2
Preparation of Silicon-Containing Middle Layer Film Composition
A silicon-containing polymer and an acid generator PAG1 shown below were dissolved in an organic solvent containing 0.1 mass % FC-4430 (available from Sumitomo 3M Ltd.) with the proportion shown in Table 4. The solution was filtered through a 0.1-μm filter made of a fluorine resin to prepare a silicon-containing middle layer film composition. The prepared silicon-containing middle layer film composition was applied onto a Si substrate, and baked at 200° C. for 60 seconds to form a silicon-containing middle layer film with a thickness of 40 nm. After formation of the silicon-containing middle layer film, refractive index (n, k) at 193 nm wavelength was measured by a spectroscopic ellipsometer with a variable incident light angle (VASE) manufactured by J. A. Woollam Co., Inc. The result is given in Table 4.


















TABLE 4








Acid
Organic






Polymer
generator
solvent



(parts by
(parts by
(parts by
Water (parts by
n-
k-



mass)
mass)
mass)
mass)
value
value






















Silicon-
Silicon-
PAG1 (2.0)
PGEE
Water
1.62
0.21


containing
containing

(4000)
(60)


middle layer
polymer (100)


film


composition





PGEE: propylene glycol ethyl ether






Preparation of Resist Upper Layer Film Composition
A resist polymer, an acid generator PAG2, and a quencher shown below were dissolved in an organic solvent containing 0.1 mass % FC-4430 (available from Sumitomo 3M Ltd.) with the proportion shown in Table 5. The solution was filtered through a 0.1-μm filter made of a fluorine resin to prepare a resist upper layer film composition (ArF Resist film composition).











TABLE 5









Organic


Resist upper


Quencher
solvent


layer film
Polymer
Acid generator
(parts by
(parts by


composition
(parts by mass)
(parts by mass)
mass)
mass)







ArF resist film
Resist polymer
PAG2 (6.0)
Quencher
PGMEA


composition
(100)

(5.0)
(2000)









Resist Polymer

Molecular weight (Mw)=7,500
Dispersity (Mw/Mn)=1.92




[Pattern Etching Test]

The produced resist under layer film compositions (Under layer film compositions 1 to 10, Comparative under layer film compositions 1 and 2) were each applied onto a 300-mm Si wafer having a SiO2 film 80 nm thick, and baked at 350° C. for 60 seconds to form a resist under layer film having a thickness of 100 nm. The baking atmosphere of the resist under layer film was in air. The prepared silicon-containing middle layer film composition was applied thereon and baked at 200° C. for 60 seconds to form a silicon-containing middle layer film having a thickness of 35 nm, and the ArF resist film composition was applied thereon and baked at 105° C. for 60 seconds to form an ArF resist film having a thickness of 100 nm.
Then, the Si wafer substrate on which the 3-layer film has been formed as mentioned above was exposed to light with an ArF liquid immersion exposure apparatus (NSR-S610C manufactured by Nikon Corporation, NA: 1.30, σ: 0.98/0.65, 35° dipole s-polarized illumination, 6% halftone phase shift mask), baked at 100° C. for 60 seconds (PEB), and developed with a 2.38 mass % tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds to obtain a 43 nm 1:1 positive line and space pattern.
Then, the pattern was transferred to the silicon-containing middle layer film by dry etching using the formed resist pattern as a mask with an etching apparatus Telius manufactured by Tokyo Electron Ltd. In the same manner, the pattern was transferred to the resist under layer film by dry etching using the silicon-containing middle layer film having the transferred pattern as a mask. The pattern was further transferred to the SiO2 film by dry etching using the resist under layer film having the transferred pattern as a mask.
The etching condition was as follows.
Transferring Condition to Silicon-Containing Middle Layer Film

















Chamber pressure
10.0
Pa



RF power
1,500
W



CF4 gas flow rate
15
sccm (mL/min)



O2 gas flow rate
75
sccm (mL/min)



Time
15
sec










Transferring Condition to Resist Under Layer Film


















Chamber pressure
2.0
Pa



RF power
500
W



Ar gas flow rate
75
sccm (mL/min)



O2 gas flow rate
45
sccm (mL/min)



Time
120
sec










Transferring Condition to SiO2 Film


















Chamber pressure
2.0
Pa



RF power
2,200
W



C5F12 gas flow rate
20
sccm (mL/min)



C2F6 gas flow rate
10
sccm (mL/min)



Ar gas flow rate
300
sccm (mL/min)



O2 gas flow rate
60
sccm (mL/min)



Time
90
sec










Then, the wafer after etching was cut, and cross-section of the pattern was observed with an electron microscope (S-4700) manufactured by Hitachi, Ltd., to compare pattern profiles after etching in each etching step and wiggling of the pattern after etching of the SiO2 film. The result is given in Table 6.














TABLE 6









Profile
Profile

Wiggling of





after
after
Profile
pattern




Pattern
etching for
etching for
after
after



Resist under
profile
transfer to
transfer to
etching for
etching for



layer film
after
middle
under layer
transfer to
transfer to



composition
development
layer film
film
substrate
substrate






















Example 3-1
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 1


Example 3-2
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 2


Example 3-3
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 3


Example 3-4
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 4


Example 3-5
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 5


Example 3-6
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 6


Example 3-7
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 7


Example 3-8
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 8


Example 3-9
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition 9


Example 3-10
Under layer
Vertical
Vertical
Vertical
Vertical
None



film
profile
profile
profile
profile



composition



10


Comparative
Comparative
Vertical
Vertical
Vertical
Vertical
None


example 3-1
under layer
profile
profile
profile
profile



film



composition 1


Comparative
Comparative
Vertical
Vertical
Vertical
Vertical
None


example 3-2
under layer
profile
profile
profile
profile



film



composition 2









The result shown in Table 6 demonstrates that the inventive resist under layer film composition enabled an good pattern to be formed even after dry etching, as well as the conventional resist under layer film. In addition, it was revealed that all under layer film compositions had adequate dry-etching resistance.

## Claims

1. A resist under layer film composition comprising a novolak resin having a repeating unit shown by the formula (1) and either or both of a novolak resin having a repeating unit shown by the formula (2) and a bisnaphthol derivative shown by the formula (3),




wherein R1 and R2 represent a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms, in which the alkyl group, the alkenyl group, the aryl group, and the aralkyl group may contain a fluorine atom(s) and may further contain a hydroxyl group, an alkoxy group, an acyl group, a sulfoxide group, a sulfo group, or an ester bond, and 10% or more of a total of R1 and R2 are groups containing at least one fluorine atom; R3, R4, R11, and R12 represent a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, in which the alkyl group, the alkenyl group, and the aryl group may contain a hydroxyl group, an alkoxy group, an acyloxy group, an ether group, or a sulfide group; R18 and R19 represent a halogen atom or the same group as R3, R4, R11, and R12; R5, R6, R13, R14, R20, and R21 represent a hydrogen atom, or R5, R13, and R20 may bond to R6, R14, and R21 respectively to form an ether bond; R7 and R15 represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms, in which the alkyl group, the alkenyl group, and the aryl group may contain a hydroxyl group, an alkoxy group, an acyloxy group, an ether group, a sulfide group, a chloro group, or a nitro group; R9, R10, R16, and R17 represent a hydrogen atom, an acid-labile group, a glycidyl group, or a linear, branched, or cyclic alkyl, acyl, or alkoxycarbonyl group having 1 to 10 carbon atoms; X1, X2, and X3 represent a single bond or a linear, branched, or cyclic divalent hydrocarbon group having 1 to 38 carbon atoms and optionally containing a hydroxyl group, a carboxyl group, an ether group, or a lactone ring, when X1 is a divalent hydrocarbon group, R5 and R6 may bond to carbon atoms in X1 to form an ether bond, when X2 is a divalent hydrocarbon group, R13 and R14 may bond to carbon atoms in X2 to form an ether bond, and when X3 is a divalent hydrocarbon group, R20 and R21 may bond to carbon atoms in X3 to form an ether bond; and a, b, c, d, g, h, i, j, k, l, m, and n are each 1 or 2.

2. The resist under layer film composition according to claim 1, comprising the novolak resin having the repeating unit shown by the formula (1), the novolak resin having the repeating unit shown by the formula (2), and the bisnaphthol derivative shown by the formula (3).

3. The resist under layer film composition according to claim 1, wherein the novolak resin having the repeating unit shown by the formula (1) contains one or more groups selected from the formulae (4)-1 to (4)-5 as R1 and/or R2 in the formula (1),




wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R0 represents a hydrogen atom, a methyl group, an acetyl group, or a trifluoroacetyl group; Rf represents a fluorine atom, a linear, branched, or cyclic alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon, an aralkyl group having 7 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, in which these groups contain at least one fluorine atom and may further contain a hydroxyl group or an alkoxy group; R22 represents a hydrogen atom, a methyl group, or an ethyl group; and R23 and R24 represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

4. The resist under layer film composition according to claim 2, wherein the novolak resin having the repeating unit shown by the formula (1) contains one or more groups selected from the formulae (4)-1 to (4)-5 as R1 and/or R2 in the formula (1),




wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R0 represents a hydrogen atom, a methyl group, an acetyl group, or a trifluoroacetyl group; Rf represents a fluorine atom, a linear, branched, or cyclic alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 10 carbon, an aralkyl group having 7 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, in which these groups contain at least one fluorine atom and may further contain a hydroxyl group or an alkoxy group; R22 represents a hydrogen atom, a methyl group, or an ethyl group; and R23 and R24 represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

5. The resist under layer film composition according to claim 2, wherein a total amount of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3) is 5 to 100 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1).

6. The resist under layer film composition according to claim 3, wherein a total amount of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3) is 5 to 100 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1).

7. The resist under layer film composition according to claim 4, wherein a total amount of the novolak resin having the repeating unit shown by the formula (2) and the bisnaphthol derivative shown by the formula (3) is 5 to 100 parts by mass with respect to 1 part by mass of the novolak resin having the repeating unit shown by the formula (1).

8. The resist under layer film composition according to claim 1, further comprising an organic solvent.

9. The resist under layer film composition according to claim 1, further comprising an acid generator and/or a crosslinking agent.

10. A patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the resist under layer film composition according to claim 1; forming a silicon-containing middle layer film on the resist under layer film by using a silicon-containing middle layer film composition; forming a resist upper layer film on the silicon-containing middle layer film by using a resist upper layer film composition; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the silicon-containing middle layer film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the silicon-containing resist middle layer film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.

11. A patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the resist under layer film composition according to claim 1; forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film on the resist under layer film; forming a resist upper layer film on the inorganic hard mask intermediate film by using a resist upper layer film composition; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the inorganic hard mask intermediate film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the inorganic hard mask intermediate film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.

12. A patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the resist under layer film composition according to claim 1; forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film on the resist under layer film; forming an organic antireflection film on the inorganic hard mask intermediate film; forming a resist upper layer film on the organic antireflection film by using a resist upper layer film composition, thereby forming a 4-layer resist film; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the organic antireflection film and the inorganic hard mask intermediate film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the resist under layer film by etching using the inorganic hard mask intermediate film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.

13. A patterning process for forming a pattern in a substrate by lithography, comprising: forming a resist under layer film on a substrate to be processed by using the resist under layer film composition according to claim 1; forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon carbide film, a polysilicon film, a titanium nitride film, a titanium oxide film, a titanium carbide film, a zirconium oxide film, and a hafnium oxide film on the resist under layer film; forming a hydrocarbon film on the inorganic hard mask intermediate film by using a hydrocarbon film composition by spin coating; forming a silicon-containing middle layer film on the hydrocarbon film by using a silicon-containing middle layer film composition; forming a resist upper layer film on the silicon-containing middle layer film by using a resist upper layer film composition, thereby forming a 5-layer resist film; forming a resist pattern in the resist upper layer film by exposure of a pattern circuit region of the resist upper layer film and development; transferring the pattern to the silicon-containing middle layer film by etching using the resist upper layer film having the formed resist pattern as a mask; transferring the pattern to the hydrocarbon film by etching using the silicon-containing middle layer film having the transferred pattern as a mask; transferring the pattern to the inorganic hard mask intermediate film by etching using the hydrocarbon film having the transferred pattern as a mask; transferring the pattern to the resist under layer film by etching using the inorganic hard mask intermediate film having the transferred pattern as a mask; forming the pattern in the substrate to be processed by etching using the resist under layer film having the transferred pattern as a mask.

14. The patterning process according to claim 11, wherein the inorganic hard mask intermediate film is formed by a CVD method, an ALD method, or a sputtering method.

15. The patterning process according to claim 10, wherein the resist upper layer film composition does not contain a polymer having a silicon atom, and the etching of the resist under layer film using the silicon-containing middle layer film as a mask is performed with an etching gas containing an oxygen gas or a hydrogen gas.

16. The patterning process according to claim 11, wherein the resist upper layer film composition does not contain a polymer having a silicon atom, and the etching of the resist under layer film using the inorganic hard mask intermediate film as a mask is performed with an etching gas containing an oxygen gas or a hydrogen gas.