Composition for forming resist underlayer film, pattern forming method, and method for forming resist underlayer film

Abstract

To provide a composition for forming a resist underlayer film which functions as an antireflection film and has excellent resistance to an alkaline hydrogen peroxide solution, good embedding / flattening characteristics and dry etching characteristics, and to provide a pattern forming method and a method for forming a resist underlayer film using the composition.SOLUTION: A composition for forming a resist underlayer film, comprising: (A) a polymer compound having a specific structure and having an epoxy group and an oxetanyl group; (B) a crosslinking agent represented by the following formula (B-1); and (C) an organic solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a resist underlayer film used in fine patterning by a multilayer resist method in the manufacturing process of a semiconductor device, a pattern formation method using the composition for forming a resist underlayer film, and a method for forming a resist underlayer film. [Background technology]

[0002] In the manufacture of semiconductor devices, microfabrication using photoresist is performed through lithography. Microfabrication involves forming a thin film of photoresist on a semiconductor substrate, such as a silicon wafer, irradiating it with active light such as ultraviolet light through a mask pattern bearing a device pattern, developing the photoresist, and then etching the substrate using the resulting photoresist pattern as a protective film, thereby forming fine irregularities on the substrate surface corresponding to the pattern. However, with the recent trend toward higher device integration, the wavelength of the exposure light used has tended to be shortened from KrF excimer lasers (wavelength 248 nm) to ArF excimer lasers (wavelength 193 nm). However, these photolithography processes can cause problems, such as standing waves caused by reflection of the exposure light from the substrate and diffuse reflection of the exposure light due to unevenness in the substrate, resulting in reduced dimensional accuracy of the photoresist pattern. To address this issue, methods for imparting anti-reflective coating (Bottom Anti-Reflective Coating, BARC) functionality to the resist underlayer film provided between the photoresist and the substrate have been widely investigated.

[0003] These resist underlayer films are often formed using a thermally crosslinkable composition to prevent intermixing with the photoresist applied thereon. As a result, the formed resist underlayer film becomes insoluble in the alkaline developer used to develop the photoresist. Therefore, removal of the antireflective coating prior to semiconductor substrate processing must be performed by dry etching (e.g., Patent Document 1). However, when the resist underlayer film is dry-etched, the photoresist is also dry-etched. This makes it difficult to ensure the photoresist film thickness required for substrate processing. This is a serious problem, especially when a thin photoresist is used to improve resolution. Therefore, there is a need for a resist underlayer film that has a faster dry-etching rate than the photoresist film.

[0004] The ion implantation process in semiconductor device manufacturing is a process in which impurities are introduced into a semiconductor substrate using a photoresist pattern as a template. Until now, the photoresist pattern used as a template in the ion implantation process has a wide line width and is less susceptible to the effects of standing waves caused by reflection of exposure light from the substrate or diffuse reflection of exposure light due to steps in the substrate. Therefore, problems caused by reflection have been solved by using dye-containing photoresists or anti-reflective coatings on top of the photoresist (Patent Document 2). However, with the recent trend toward miniaturization, finer patterns are now required for the photoresists used in the ion implantation process, which has created the need for anti-reflective coatings underneath the photoresist.

[0005] Meanwhile, in recent years, active research has been conducted into the manufacture of semiconductor devices with novel structures, such as multi-gate structures. In response to this trend, the demand for resist underlayer films with superior planarization and filling properties has increased. For example, when the underlying substrate has micropattern structures, such as holes, trenches, and fins, the resist underlayer film must be able to fill the pattern without gaps (gap-filling). Furthermore, when the underlying substrate has unevenness or when densely patterned areas and unpatterned areas exist on the same wafer, the resist underlayer film must planarize the film surface. Planarizing the underlayer film surface reduces film thickness variations in the resist middle film and resist top film deposited on top of it, thereby preventing reductions in lithography focus margins and margins in subsequent processing steps of the substrate. Furthermore, substrate processing using wet etching with chemicals may be required. In such cases, the resist underlayer film, which serves as a processing mask, must also be resistant to wet etchants.

[0006] Here, we will explain in detail the background behind the demand for materials compatible with wet etching processes in relation to multilayer resist methods. To improve the performance of semiconductor devices, cutting-edge semiconductor devices use technologies such as three-dimensional transistors and through-hole wiring. Patterning using the multilayer resist method is also performed in the patterning process used to form structures within such semiconductor devices. For example, a process is being considered in which a resist underlayer film is used as an etching mask to wet-etch a workpiece substrate such as titanium nitride using alkaline hydrogen peroxide water.

[0007] As a resist underlayer film material for semiconductor device manufacturing that has a high dry etching rate and can planarize uneven substrates, Patent Document 3, for example, proposes a material containing a polymer compound such as polyglycidyl methacrylate. Furthermore, as a resist underlayer film material for semiconductor device manufacturing that has a high dry etching rate, Patent Document 4 proposes a material containing a copolymer produced using monomers such as (meth)acrylic acid and glycidyl (meth)acrylate, and Patent Document 5 proposes a material containing a copolymer produced using monomers such as hydroxypropyl methacrylate and a crosslinker. Patent Document 6 proposes a resin composition containing any of a phenolic hydroxyl group, a carboxyl group, a sulfonic acid group, or a sulfonylamic acid group. However, these known materials have the problem of insufficient resistance to alkaline hydrogen peroxide solution.

[0008] Furthermore, Patent Document 7 proposes a material containing a polymer having an epoxy group and a carboxyl group (acetal-protected ester) protected with a vinyl ether compound as a resist underlayer film material having alkaline hydrogen peroxide resistance. Patent Document 8 also proposes a material containing a polymer having an epoxy group and a carboxyl group protected with a tertiary alkyl group as a resist underlayer film having excellent dry etching properties, good alkaline hydrogen peroxide resistance, and excellent planarization properties. However, these known materials have insufficient planarization properties and are not suitable for patterning substrates having unevenness or steps, which is particularly required in cutting-edge processes. Furthermore, the alkaline hydrogen peroxide resistance of these materials is still insufficient for practical use.

[0009] As described above, there is a need for a resist underlayer film material for use in semiconductor device manufacturing that has anti-reflection properties, high compatibility with wet etching processes (i.e., resistance to alkaline hydrogen peroxide solution), and also has good filling / planarization properties and dry etching properties, and a pattern formation method using the same. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] U.S. Patent No. 6,156,479 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-197606 [Patent Document 3] Japanese Patent Application Laid-open No. 61-180241 [Patent Document 4] Japanese Patent Application Publication No. 6-118656 [Patent Document 5] Special Publication No. 2002-502982 [Patent Document 6] Japanese Patent Application Laid-Open No. 2009-098651 [Patent Document 7] WO2015 / 030060 publication [Patent Document 8] Japanese Patent Application Laid-Open No. 2016-185999 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composition for forming a resist underlayer film that functions as an antireflective film and has excellent alkaline hydrogen peroxide solution resistance, good filling / planarization properties, and dry etching properties, a pattern formation method using the same, and a method for forming a resist underlayer film. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention provides: A composition for forming a resist underlayer film, (A) A polymer compound having a structural unit (a1) represented by the following formula (A-1) and at least one structural unit (a2) selected from the structural units represented by the following formulas (A-2) to (A-4): (B) a crosslinking agent represented by the following formula (B-1): (C) organic solvent, The present invention provides a composition for forming a resist underlayer film, which comprises: [ka] (In the formula, R 01 is a hydrogen atom or a methyl group, and R 02 is a monovalent organic group containing a group selected from groups represented by the following formulas (R2-1) to (R2-3): [ka] (In the formula, R a represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the dashed line represents a bond. [ka] (In formula (A-2), X represents an aromatic ring having 6 to 20 carbon atoms or a single bond, and R 03 is a hydrogen atom or a methyl group, and R 04 is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and R 04 When R is an alkyl group, a hydrogen atom constituting the alkyl group may be substituted with a hydroxyl group. 05 is a hydrogen atom or a methyl group, and R 06 is a divalent linking group having 2 to 10 carbon atoms and containing a single bond or an ester group, and R 07 is a tertiary alkyl group having 4 to 20 carbon atoms or a tertiary alkenyl group having 5 to 20 carbon atoms. 05 , R 06 has the same meaning as in formula (A-3), and R 08 is a hydrogen atom or a monovalent primary alkyl group having 1 to 10 carbon atoms. [ka] (In the formula, R 5 represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following (B-2), and R 1 , R 3 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 2 , R 4 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group. [ka] (In the formula, R 7 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 6 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and R 2 , R 4 When is a hydrogen atom, R 6 is also a hydrogen atom.)

[0013] Such a composition for forming a resist underlayer film can have good alkaline hydrogen peroxide resistance, excellent filling / planarization properties, and excellent dry etching properties in addition to anti-reflection properties.

[0014] In the formula (B-1), R 1 , R 3 , R 7 Preferably, two or more of the groups are naphthoyl groups or anthranoyl groups.

[0015] A composition for forming a resist underlayer film containing such a crosslinking agent can be made to be capable of absorbing exposure light such as that from a KrF excimer laser, thereby reducing the effects of standing waves caused by reflection of the exposure light from the substrate and diffuse reflection of the exposure light due to step portions in a stepped substrate, thereby improving the resolution of the resist overlayer film during lithography.

[0016] In addition, in the formula (B-1), R 2 , R 4 , R 5 It is preferred that either one of the above has an unsaturated bond other than an aromatic bond.

[0017] A composition for forming a resist underlayer film containing such a crosslinking agent can improve fluidity and provide even better filling and flattening properties.

[0018] The content of the (B) crosslinking agent contained in the composition for forming a resist underlayer film is preferably in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the (A) polymer compound.

[0019] A composition for forming a resist underlayer film having a crosslinker content within this range can have anti-reflection properties as well as good alkaline hydrogen peroxide resistance, excellent filling / planarization properties, and excellent dry etching properties. It can also suppress the generation of sublimates during heat curing and prevent equipment contamination by the sublimates. Furthermore, it can suppress the occurrence of coating defects and achieve even better filling / planarization properties.

[0020] The (A) polymer compound preferably has a structural unit (a1) represented by the formula (A-1) and at least two structural units (a2) selected from the structural units represented by the formulas (A-2) to (A-4).

[0021] If the polymer compound contains such a repeating unit, it becomes possible to adjust the etching properties such as the etching rate and the post-etching pattern shape in accordance with customer requirements without deteriorating the optical properties of the composition for forming a resist underlayer film containing the polymer compound.

[0022] In the (A) polymer compound, it is preferred that the content of the structural unit (a1) is 20 mol % or more and 90 mol % or less of all repeating units, and the total content of the structural unit (a2) is 10 mol % or more and 80 mol % or less.

[0023] When the content is within this range, the composition for forming a resist underlayer film containing this polymer compound as a base resin can be made even more excellent in alkaline hydrogen peroxide resistance, thermosetting properties, filling / planarization properties, and dry etching properties.

[0024] The weight average molecular weight of the (A) polymer compound is preferably 1,000 to 20,000.

[0025] If the weight-average molecular weight of component (A) is 1,000 or more, it has good film-forming properties and is free from the risk of equipment contamination due to an increase in sublimates during heat curing. Furthermore, if the weight-average molecular weight is 20,000 or less, coating defects do not occur and fluidity is good, resulting in sufficient planarization and filling properties.

[0026] The polydispersity of the polymer compound (A), expressed as weight average molecular weight / number average molecular weight, is preferably 3.0 or less.

[0027] By setting the dispersity of the polymer compound within this range, excellent film-forming properties can be obtained, and the generation of sublimates during heat curing can be suppressed, thereby preventing contamination of the apparatus.

[0028] The composition for forming a resist underlayer film of the present invention preferably contains at least one selected from (D) an acid generator and (E) a surfactant.

[0029] The composition for forming a resist underlayer film of the present invention may contain additives such as those described above for the purposes of accelerating a crosslinking reaction due to heat or the like, and improving the coatability, curability, and planarization / filling properties in spin coating, and the resolution in patterning in multilayer lithography.

[0030] The composition for forming a resist underlayer film preferably provides a resist underlayer film that is resistant to an ammonia-containing aqueous hydrogen peroxide solution.

[0031] Such a composition for forming a resist underlayer film can form a resist underlayer film having good resistance to alkaline hydrogen peroxide solution, and therefore can be applied to a wet etching process using alkaline hydrogen peroxide solution.

[0032] In the present invention, there is provided a method for forming a pattern on a substrate to be processed, comprising the steps of: (I-1) a step of applying the composition for forming a resist underlayer film described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a composition for forming a resist upper layer film; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the resist underlayer film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; The present invention provides a pattern forming method comprising the steps of:

[0033] The present invention also provides a method for forming a pattern on a substrate to be processed, comprising the steps of: (II-1) a step of applying the composition for forming a resist underlayer film described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (II-2) forming a silicon atom-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon atom-containing resist intermediate film using a composition for forming a resist upper layer film; (II-4) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (II-5) a step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the silicon atom-containing resist intermediate film to which the pattern has been transferred as a mask; The present invention provides a pattern forming method comprising the steps of:

[0034] Furthermore, the present invention provides a method for forming a pattern on a substrate to be processed, comprising the steps of: (III-1) a step of applying the composition for forming a resist underlayer film described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (III-2) forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film; (III-3) forming an organic anti-reflective coating on the inorganic hard mask; (III-4) forming a resist upper layer film on the organic antireflective film using a composition for forming a resist upper layer film; (III-5) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (III-6) a step of transferring a pattern to the organic anti-reflective film and the inorganic hard mask by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (III-7) a step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask to which the pattern has been transferred as a mask; The present invention provides a pattern forming method comprising the steps of:

[0035] As described above, the pattern formation method of the present invention makes it possible to form fine patterns using a multilayer resist method (two-layer resist process, three-layer resist process, or four-layer resist process), and also makes it possible to fill in steps on the substrate to be processed and flatten the substrate to be processed by forming a resist underlayer film.

[0036] Furthermore, the pattern forming method described above may further include, after the step (I-4), the step (II-6), or the step (III-7), a step of transferring a pattern to the workpiece substrate by wet etching using an alkaline hydrogen peroxide solution, using the resist underlayer film to which the pattern has been transferred as a mask.

[0037] The resist underlayer film formed using the composition for forming a resist underlayer film of the present invention has good resistance to alkaline hydrogen peroxide solution, and therefore, as described above, can be subjected to pattern transfer onto a substrate to be processed by wet etching using alkaline hydrogen peroxide solution.

[0038] The pattern formation method described above may further include, after the step (I-4), the step (II-6), or the step (III-7), a step of patterning the workpiece substrate by performing ion implantation using the resist underlayer film to which the pattern has been transferred as a mask.

[0039] Such a pattern forming method is particularly suitable for ion implantation processing of a substrate having an uneven surface.

[0040] It is preferable to use a composition for forming a resist underlayer film that has a higher dry etching rate than the dry etching rate of the resist upper layer film.

[0041] By using such a composition for forming a resist underlayer film, the resist underlayer film used as a mask can be removed by dry etching without leaving any residue, making it possible to manufacture a semiconductor device with fewer defects.

[0042] In this case, it is preferable to use a substrate having a structure or step having a height of 30 nm or more as the substrate to be processed.

[0043] The resist underlayer film formed using the composition for forming a resist underlayer film of the present invention has excellent filling / planarizing properties, and therefore a flat resist underlayer film without voids can be formed even on a substrate having structures or steps with a height of 30 nm or more.

[0044] The present invention provides a method for forming a resist underlayer film used in the manufacturing process of a semiconductor device, which comprises spin-coating the composition for forming a resist underlayer film described above onto a substrate to be processed, and heat-treating the substrate coated with the composition for forming a resist underlayer film at a temperature of 100°C or higher and 300°C or lower for 10 to 600 seconds to form a resist underlayer film.

[0045] This method for forming a resist underlayer film can form a resist underlayer film that has good alkaline hydrogen peroxide resistance, excellent filling / planarization properties, and excellent dry etching properties. Furthermore, by appropriately adjusting the baking temperature and time within the above ranges, it is possible to obtain planarization / filling properties and curing properties suitable for the application. [Effects of the Invention]

[0046] As described above, the composition for forming a resist underlayer film of the present invention can form a resist underlayer film that has, in addition to antireflection properties, good alkaline hydrogen peroxide solution resistance, excellent filling / planarization properties, and excellent dry etching properties. Furthermore, the pattern formation method of the present invention makes it possible to form a fine pattern using a multilayer resist method (two-layer resist process, three-layer resist process, or four-layer resist process), and also makes it possible to fill steps on a substrate to be processed and planarize the substrate to be processed by forming a resist underlayer film. Therefore, the pattern formation method of the present invention is suitably used in a wet etching process, a planarization process using an underlayer film, and a process for removing an underlayer film using dry etching, and is extremely useful as a pattern formation method used in a multilayer resist process applied to fine patterning for manufacturing semiconductor devices. Furthermore, the method for forming a resist underlayer film of the present invention makes it possible to form a resist underlayer film that has good alkaline hydrogen peroxide resistance, excellent filling / planarization properties, and excellent dry etching properties. [Brief explanation of the drawings]

[0047] [Figure 1] 1A to 1C are explanatory diagrams illustrating an example of a pattern formation method using a three-layer resist process according to the present invention. [Figure 2] FIG. 1 is an explanatory diagram of a method for evaluating filling characteristics in Examples and Comparative Examples. [Figure 3] 1A and 1B are explanatory diagrams of a method for evaluating flattening characteristics in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0048] As described above, there has been a demand for a composition for forming a resist underlayer film that has a good antireflection function, excellent resistance to alkaline hydrogen peroxide solution, and good filling / planarization properties and dry etching properties, as well as a pattern formation method and a resist underlayer film formation method using the same.

[0049] The present inventors have searched for various compositions for forming resist underlayer films and pattern formation methods in order to realize wet etching processing in multilayer lithography using resist underlayer films, and preferably to enable both filling and planarization by forming an underlayer film and dry etching removal of the underlayer film at the same time. As a result, they have found that a composition for forming resist underlayer films, mainly composed of a polymer compound with a specific structure and a crosslinker with a specific structure, and a pattern formation method using the same, are very effective, and have completed the present invention.

[0050] That is, the present invention provides: A composition for forming a resist underlayer film, (A) A polymer compound having a structural unit (a1) represented by the following formula (A-1) and at least one structural unit (a2) selected from the structural units represented by the following formulas (A-2) to (A-4): (B) a crosslinking agent represented by the following formula (B-1): (C) organic solvent, The composition for forming a resist underlayer film is characterized by comprising: [ka] (In the formula, R 01 is a hydrogen atom or a methyl group, and R 02 is a monovalent organic group containing a group selected from groups represented by the following formulas (R2-1) to (R2-3): [ka] (In the formula, R a represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the dashed line represents a bond. [ka] (In formula (A-2), X represents an aromatic ring having 6 to 20 carbon atoms or a single bond, and R 03 is a hydrogen atom or a methyl group, and R 04 is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and R 04 When R is an alkyl group, a hydrogen atom constituting the alkyl group may be substituted with a hydroxyl group. 05 is a hydrogen atom or a methyl group, and R 06 is a divalent linking group having 2 to 10 carbon atoms and containing a single bond or an ester group, and R 07 is a tertiary alkyl group having 4 to 20 carbon atoms or a tertiary alkenyl group having 5 to 20 carbon atoms. 05 , R 06 has the same meaning as in formula (A-3), and R 08 is a hydrogen atom or a monovalent primary alkyl group having 1 to 10 carbon atoms. [ka] (In the formula, R 5 represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following (B-2), and R 1 , R 3 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 2 , R 4 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group. [ka] (In the formula, R 7 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 6 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and R 2 , R 4 When is a hydrogen atom, R 6 is also a hydrogen atom.)

[0051] The present invention will be explained in more detail below, but the present invention is not limited thereto.

[0052] [Resist Underlayer Film Materials] The composition for forming a resist underlayer film of the present invention is a composition for forming a resist underlayer film used in a multi-layer resist method, (A) A polymer compound characterized by having a structural unit (a1) represented by the following formula (A-1) and, in addition, at least one structural unit (a2) represented by the following formulas (A-2) to (A-4): (B) a crosslinking agent represented by the following formula (B-1): (C) organic solvent, The composition for forming a resist underlayer film is characterized by comprising: [ka] (In the formula, R 01 is a hydrogen atom or a methyl group, and R 02 is a monovalent organic group containing a group selected from the following formulas (R2-1) to (R2-3): [ka] (In the formula, R a represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the dashed line represents a bond. [ka] (In formula (A-2), X represents an aromatic ring having 6 to 20 carbon atoms or a single bond, and R 03 is a hydrogen atom or a methyl group, and R 04 is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and R 04 When R is an alkyl group, a hydrogen atom constituting the alkyl group may be substituted with a hydroxyl group. 05 is a hydrogen atom or a methyl group, and R 06 is a divalent linking group having 2 to 10 carbon atoms and containing a single bond or an ester group, and R 07 is a tertiary alkyl group having 4 to 20 carbon atoms or a tertiary alkenyl group having 5 to 20 carbon atoms.05 , R 06 has the same meaning as in formula (A-3), and R 08 is a hydrogen atom or a monovalent primary alkyl group having 1 to 10 carbon atoms. [ka] (In the formula, R 5 represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following (B-2), and R 1 , R 3 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 2 , R 4 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group. [ka] (In the formula, R 7 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 6 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and R 2 , R 4 When is a hydrogen atom, R 6 is also a hydrogen atom.)

[0053] [(A) Polymer compound] The polymer compound (A) is a polymer compound having a structural unit (a1) represented by the above formula (A-1) and at least one structural unit (a2) selected from the structural units represented by the above formulas (A-2) to (A-4). The repeating unit structure (a1) represented by the above formula (A-1) imparts sufficient thermosetting properties to the polymer and also prevents intermixing with the upper layer film. It is also thought to contribute to a certain degree to alkaline hydrogen peroxide resistance.

[0054] In the above formula (A-1), R 01 is a hydrogen atom or a methyl group. 01When R is a hydrogen atom, the polymer compound (A-1) may have excellent fluidity, resulting in excellent flattening / filling properties, or may have a low carbon content, resulting in an excellent etching rate. 01 When R is a methyl group, the resist underlayer film material of the present invention may have excellent film-forming applicability. 02 is a monovalent organic group containing a group selected from the groups represented by the above formulas (R2-1) to (R2-3).

[0055] The polymer compound (A) may contain only one type of repeating unit (a) represented by the formula (A-1), or may contain two or more types. Specific examples of the repeating unit represented by the formula (A-1) are as follows: [ka]

[0056] The polymer compound (A) preferably has a repeating unit structure (a1) represented by the above formula (A-1) and, in addition, at least one structural unit (a2) represented by the above formulas (A-2) to (A-3).

[0057] In the formula (A-2), X is an aromatic ring having 6 to 20 carbon atoms or a single bond. X is more preferably a benzene ring, a naphthalene ring, or a single bond. By using a structure with a relatively small molecular weight as described above, the number of hydrogen bond donors per unit molecular weight increases, resulting in excellent coatability on hydrophobic surfaces.

[0058] In the formula (A-2), R 03 is a hydrogen atom or a methyl group. However, when X is an aromatic ring, from the viewpoint of polymerization reactivity during raw material synthesis, R 03 is more preferably a hydrogen atom. When X is a single bond, R 03 Whether the group is a hydrogen atom or a methyl group, the polymerization reactivity during raw material synthesis is sufficient, and the polymerization reactivity can be suitably adjusted by selecting this structure.

[0059] In the formula (A-2), R 04is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and R 04 When R is an alkyl group, a hydrogen atom constituting the alkyl group may be substituted with a hydroxyl group. 04 is more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and even more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

[0060] R in the above formula (A-2) 04 Specific examples of alkyl groups include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, a cyclopentyl group, a cyclohexyl group, and organic groups in which a hydrogen atom constituting these alkyl groups has been substituted with a hydroxyl group.

[0061] In the formula (A-2), OR 04 The structure is released during baking, generating carbocations. These carbocations react with other structures and bond, resulting in cross-linking. 04 By making the molecular weight small, it is possible to suppress film shrinkage during baking, and to prevent coating errors during baking. 04 If the molecular weight is made large, the resin structure becomes bulky, which increases the viscosity of the resin during application, and it is possible to suppress the occurrence of application errors during spin drying. 04 It is more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and even more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

[0062] Preferred examples of the repeating unit represented by the above formula (A-2) include the following structures: 03 is the same as above.

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] The structural unit represented by formula (A-2) functions as a crosslinking group and an adhesive group to the underlayer. Because it contains a nitrogen-hydrogen bond that acts as a hydrogen bond donor, it efficiently forms hydrogen bonds even on a hydrophobic underlayer film, thereby suppressing the occurrence of coating errors. Meanwhile, because this structural unit itself has crosslinking properties, the curability of the film is not impaired even if a large amount of this unit is introduced into the resin.

[0067] In the formula (A-3), R 05 is a hydrogen atom or a methyl group. 05 is preferably a hydrogen atom. In the formula (A-3), R 06 R is a single bond or a divalent linking group containing an ester group and having 2 to 10 carbon atoms. 06 Specific examples include a single bond, -CO2CH2-, -CO2CH2CH2-, -CO2CH2CH2CH2-, -CO2CH(CH3)-, -CO2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2CH2CH2-, -CO2CH2CH2O-, -CO2CH2CH2OCH2CH2OCH2CH2OCH2CH2O-, etc. Among these, -CO2CH2-, -CO2CH2CH2-, -CO2CH2CH2-, -CO2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2- and -CO2CH2CH2CH2CH2CH2- are particularly preferred.

[0068] In the above formula (A-3), R 07R is a tertiary alkyl group having 4 to 20 carbon atoms or a tertiary alkenyl group having 5 to 20 carbon atoms. 07 Specific examples of the structure include, but are not limited to, the following structures: The dashed lines indicate bonds.

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] When a resist underlayer film is formed from a polymer compound containing a repeating unit represented by the above formula (A-3), the tertiary alkyl group R 07 The elimination and decomposition reaction of the above proceeds to generate a carboxylic acid. The polarity of this carboxylic acid improves the adhesion to the resist pattern, improves the rectangularity of the pattern, and prevents the generation of residues in the spaces of the pattern.

[0073] In addition, the carboxylic acid generated from (A-3) may undergo a ring-opening addition reaction with the repeating unit represented by formula (A-1) to form a hydroxy ester crosslinked structure. A typical example of this reaction is shown below. In the following formula, R in the repeating unit (A-3) 07 The state in which the alkyl group is eliminated to form a carboxylic acid is (A-3'), and the state in which the alkyl group is subjected to a ring-opening addition reaction with (A-1'), which is an example of the above formula (A-1), to form a hydroxy ester crosslinked structure is (A-3''). In this way, a hydroxy ester crosslinked structure is formed by this crosslinking reaction. [ka]

[0074] The crosslinking reaction that forms this hydroxyester crosslink structure accelerates the curing of the resist underlayer film. Sufficient curing results in the formation of a dense film, preventing intermixing between the resist underlayer film and the resist overlayer film, thereby preventing residues from forming in the spaces of the pattern and enabling the formation of highly rectangular patterns.

[0075] Furthermore, the hydroxy ester crosslinked structure is a polar group and interacts with the resist pattern, so the presence of the repeating unit (A-3) also contributes to preventing the resist pattern from collapsing.

[0076] In the above formula (A-4), R 05 and R 06 is the same as in the above formula (A-3), and R 08 is a hydrogen atom or a monovalent primary alkyl group having 1 to 10 carbon atoms. 08 is more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and even more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

[0077] R in the above formula (A-4) 08 Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group.

[0078] When the (A) polymer compound contains a structural unit represented by the above formula (A-4), the flowability of the polymer compound can be improved, and the composition for forming a resist underlayer film can have excellent filling / planarization properties.

[0079] In the present invention, the content of the structural unit (a1) in the polymer compound (A) relative to all repeating units is preferably 20 mol % or more and 90 mol % or less, more preferably 25 mol % or more and 80 mol % or less. If it is 20% or more, sufficient curing ability is obtained. If it is 90% or less, sufficient etching properties are obtained. The content of the structural unit (a2) relative to all repeating units is preferably 10 mol % to 80 mol %, more preferably 20 mol % to 75 mol %. If it is 10% or more, sufficient resolution is obtained during upper layer resist lithography, and if it is 80% or less, sufficient filling / planarization properties are obtained.

[0080] In order to ensure the fluidity of the polymer compound from the viewpoint of filling and planarization properties, it is preferable that the repeating unit of the (A) polymer compound does not contain an aromatic group with a large molecular weight, such as a naphthalene or anthracene structure. If a naphthalene or anthracene structure is introduced into the repeating unit of the (A) polymer compound from the viewpoint of imparting anti-reflection properties, the filling and planarization properties will deteriorate. On the other hand, in the present invention, by introducing an aromatic compound unit (ultraviolet absorbing group) into the crosslinking group component, it is possible to achieve both anti-reflection properties and filling / planarization properties. Furthermore, by combining a specific crosslinking group component with the polymer compound in a certain ratio range, it is possible to achieve both alkaline hydrogen peroxide resistance and resistance.

[0081] The (A) polymer compound preferably has a weight-average molecular weight of 1,000 to 20,000. The weight-average molecular weight is based on the value measured by gel permeation chromatography (tetrahydrofuran solvent, polystyrene standard). The weight-average molecular weight of the (A) polymer compound is preferably 1,000 to 20,000, more preferably 1,500 to 15,000, and even more preferably 2,000 to 10,000. If the weight-average molecular weight of the (A) component is 1,000 or more, the film-forming properties are good and there is no risk of equipment contamination due to an increase in sublimates during heat curing. Furthermore, if the weight-average molecular weight is 20,000 or less, coating defects do not occur and the fluidity is good, resulting in sufficient planarization / filling properties.

[0082] In addition, in the resist underlayer film material of the present invention, the GPC dispersity of the polymer compound (A) is preferably 3.0 or less, and more preferably 2.0 or less. A composition for forming a resist underlayer film containing such a polymer compound (A) generates less sublimate during resist underlayer film formation, can suppress equipment contamination, and is highly practical.

[0083] The (A) polymer compound preferably has a structural unit (a1) represented by the formula (A-1) and at least two structural units (a2) selected from the structural units represented by the formulas (A-2) to (A-4).

[0084] If the polymer compound contains such a repeating unit, it becomes possible to adjust the etching properties such as the etching rate and the post-etching pattern shape in accordance with customer requirements without deteriorating the optical properties of the composition for forming a resist underlayer film containing the polymer compound.

[0085] Specific examples of the polymer compound (A) in the composition for forming a resist underlayer film of the present invention include, but are not limited to, the following polymers: t Bu represents a t-butyl group, and so on. Specific examples include (A1) to (A6) shown in the synthesis examples in the Examples.

[0086] [ka]

[0087] One method for synthesizing the (A) polymeric compound involves mixing monomers having polymerizable unsaturated bonds corresponding to each repeating unit, adding a radical initiator in a solvent, and carrying out thermal polymerization, thereby obtaining a polymeric compound. Polymerization conditions can be selected from a variety of options depending on the monomers used, the target molecular weight, and other factors, and are not particularly limited. Specific examples of solvents used during polymerization include toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, 2-butanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, cyclohexanone, γ-butyrolactone, ethyl acetate, and butyl acetate. Examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. Furthermore, thiols such as octanethiol and 2-mercaptoethanol may be added as chain transfer agents during polymerization. The polymerization reaction can be carried out by heating, preferably at 40°C to the boiling point of the reaction solvent. The reaction time is 0.5 to 100 hours, preferably 1 to 48 hours.

[0088] For example, by using compounds having a polymerizable double bond represented by the following formulae (1a), (2a), (3a), and (4a) as monomers and carrying out the polymerization as described above, polymer compounds having repeating units represented by the formulae (A-1), (A-2), (A-3), and (A-4) can be synthesized. [ka] (In the above formulas (1a), (2a), (3a), and (4a), R 01 ~R 08 , X is the same as above.)

[0089] During polymerization, all raw materials may be mixed and then heated, or the remaining raw materials may be added all at once or gradually to a portion of the raw materials that have been heated in advance, either individually or as a mixture. For example, a polymerization method in which only the polymerization solvent is heated and the monomer solution and the initiator solution are added separately and gradually to the heated solvent is particularly preferred, since it can produce a relatively homogeneous polymer compound and can prevent abnormal reactions such as runaway reactions.

[0090] The polymerization liquid obtained as described above may be blended directly into a composition for forming a resist underlayer film, or may be purified, as necessary, using conventional methods such as crystallization, separation, filtration, and concentration to remove residual monomers, residual solvents, reaction by-products, and other impurities. When purifying the (A) polymer compound, a crystallization method in which a poor solvent such as water, a water-containing alcohol, or a saturated hydrocarbon is added to the polymerization liquid and the resulting precipitate is collected by filtration, or a separation method in which a poor solvent layer is separated and removed, is preferred, with the separation method being particularly preferred. Purifying the polymer compound by a separation method allows efficient removal of low-molecular-weight components from the polymerization liquid, thereby reducing the generation of sublimates when forming a resist underlayer film from a composition for forming a resist underlayer film containing the polymer compound, which is preferred from the viewpoint of preventing contamination of the film-forming equipment.

[0091] [(B) Crosslinking agent] The crosslinking agent used in the composition for forming a resist underlayer of the present invention has a structure represented by the above formula (B-1). [ka] (In the formula, R 5 represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following (B-2), and R 1 , R 3 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 2 , R 4 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group. [ka] (In the formula, R 7represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 6 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and R 2 , R 4 When is a hydrogen atom, R 6 is also a hydrogen atom.)

[0092] A composition for forming a resist underlayer film containing such a crosslinking agent can absorb ultraviolet light and suppress reflection, particularly in a lithography process using an ultraviolet laser such as an ArF laser or a KrF laser, and exhibits good adhesion to a resist pattern formed thereon. In addition to the anti-reflection function, the composition can also have good resistance to alkaline hydrogen peroxide solution, excellent filling / planarization properties, and excellent dry etching properties.

[0093] R in the above formula (B-1) 1 , R 3 The benzoyl group, toluoyl group, naphthoyl group, and anthranoyl group are groups that absorb ultraviolet light (hereinafter also referred to as ultraviolet absorbing groups). In terms of absorption wavelength, those containing a benzoyl group or a toluoyl group are preferred for ArF (193 nm) exposure, and those containing a naphthoyl group or anthranoyl group are preferred for KrF (248 nm) exposure.

[0094] In the present invention, in order to achieve high-level filling / planarization properties and ensure fluidity, benzoyl, toluoyl, naphthoyl, and anthranoyl groups are introduced into the crosslinking agent (B), which is a monomolecular compound, rather than into the polymer compound (A). The substituent on the aromatic ring of the benzoyl group, toluoyl group, naphthoyl group, and anthranoyl group is preferably a non-polar substituent such as an alkyl group, and more preferably is unsubstituted. For example, the polarity of the monomolecular compound (B-1) increases when polar groups such as amide or hydroxyl groups are introduced as substituents. This leads to an increase in viscosity when forming the underlayer film, leading to a deterioration in filling and planarization properties. Furthermore, if the polymer compound contains hydroxyl groups that are highly reactive with the crosslinking units, the temperature at which the curing reaction occurs becomes lower, preventing the benefits of thermal flow and leading to a deterioration in filling and planarization properties.

[0095] R in the above formula (B-1) 1 , R 3 , R 7 Preferably, two or more of these are benzoyl, toluoyl, naphthoyl or anthranoyl groups, and from the viewpoint of suppressing reflected light from the substrate, they are preferably either naphthoyl or anthranoyl groups.

[0096] R in the above formula (B-1) 2 , R 4 is preferably any one of a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and from the viewpoint of embedding / flattening, is more preferably any one of an acetyl group, an acryloyl group, or a methacryloyl group.

[0097] R in the above formula (B-1) 5 represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or any of the above formula (B-2).

[0098] In addition, in the formula (B-1), R 2 , R 4 , R 5 It is preferred that either one of the above has an unsaturated bond other than an aromatic bond.

[0099] A composition for forming a resist underlayer film containing such a crosslinking agent can improve fluidity and provide even better filling and flattening properties.

[0100] R in the above formula (B-1) 5From the viewpoint of embedding / planarization, is more preferably any one of a methyl group, an ethyl group, a propyl group, an allyl group and a propargyl group, and further preferably any one of an allyl group and a propargyl group.

[0101] In the above formula (B-2), R 7 represents any one of a benzoyl group, a toluoyl group, a naphthoyl group, and anthranoyl group. 1 , R 3、 R 7 are preferably the same substituents.

[0102] In the above formula (B-2), R 6 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and R 2 , R 4 When is a hydrogen atom, R 6 is also a hydrogen atom.

[0103] Specific examples of the compound represented by the above formula (B-1) include the following compounds. [ka]

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] The molecular weight of the (B) crosslinking agent is preferably 500 to 1500, more preferably 600 to 100. A molecular weight within this range can impart embeddability and flatness, and further, there is no outgassing due to a molecular weight that is too small, or degradation of embeddability and flatness due to a molecular weight that is too large.

[0114] The molecular weight distribution of the (B) crosslinking agent (the ratio Mw / Mn of the weight average molecular weight Mw in terms of polystyrene equivalent by gel permeation chromatography to the number average molecular weight Mn) is preferably 1.00≦Mw / Mn≦1.25. Strictly speaking, if the compound is a monomolecular compound, the molecular weight distribution will be 1.00. However, it is difficult to achieve 1.00 because of the measurement conditions of the device for measuring the molecular weight distribution, the polarity of the molecule used in the crosslinking agent, and the possibility of using a compound with multiple terminal group structures. Therefore, in order to define that the compound is not a high molecular weight compound, the above molecular weight distribution range is used as a preferred range in the present invention as a numerical value that reinforces the fact that the compound is a monomolecular compound.

[0115] The blending amount of the (B) crosslinking agent is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the (A) polymer compound.

[0116] When the amount of (B) crosslinking agent is 1 part by mass or more, the composition for forming a resist underlayer film can absorb ultraviolet light and suppress reflection, particularly in lithography processes using ultraviolet lasers such as ArF lasers and KrF lasers. In addition to the anti-reflection function, the composition also exhibits good resistance to alkaline hydrogen peroxide solutions and excellent filling and planarization properties. When the blending amount of (B) crosslinking agent is 50 parts by mass or less, when used in a composition for forming a resist underlayer film, the composition exhibits good adhesion to the resist pattern, and can improve filling / planarization properties without deteriorating the etching rate.

[0117] [(C) Solvent] The component (C) in the composition for forming a resist underlayer film of the present invention is an organic solvent. The organic solvent (C) that can be used in the resist underlayer film material of the present invention is not particularly limited as long as it can dissolve the polymer compound (A) and the crosslinking agent (B), and is preferably one that can also dissolve the acid generator (D) and surfactant (E) described below. Specifically, the solvents described in paragraphs (0091) and (0092) of JP 2007-199653 A can be added. Among them, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,6-hexanediol diacetate, γ-butyrolactone, and mixtures of two or more thereof are preferably used. The amount of the organic solvent to be added is preferably adjusted depending on the intended thickness of the resist underlayer film. Generally, the amount of the organic solvent to be added is 500 to 1000 parts by mass per 100 parts by mass of the polymer compound (A).000 parts by mass.

[0118] [(D) Acid generator] In the composition for forming a resist underlayer film of the present invention, an acid generator (D) can be added to further promote the crosslinking reaction due to heat, etc. Acid generators include those that generate an acid by thermal decomposition and those that generate an acid by light irradiation, and either can be added.

[0119] Examples of the acid generator (D) that can be used in the composition for forming a resist underlayer film of the present invention include: i. Onium salts, including those represented by the following formula (P1a-1), (P1a-2), (P1a-3) or (P1b): ii. Diazomethane derivatives, including those of formula (P2): iii. Glyoxime derivatives, also including those of formula (P3): iv. Bis-sulfone derivatives, including those of formula (P4): v. Sulfonic acid esters of N-hydroxyimide compounds, including those represented by formula (P5): vi. β-ketosulfonic acid derivatives, vii. Disulfone derivatives, viii. Nitrobenzyl sulfonate derivatives, ix. Sulfonic acid ester derivatives etc.

[0120] [ka] (In the formula, R 101a , R 101b , R 101c each independently represents a linear, branched, or cyclic alkyl group, alkenyl group, oxoalkyl group, or oxoalkenyl group having 1 to 12 carbon atoms; an aryl group having 6 to 20 carbon atoms; or an aralkyl group or aryloxoalkyl group having 7 to 12 carbon atoms. Some or all of the hydrogen atoms in these groups may be substituted with alkoxy groups or the like. 101b and R 101c may form a ring, and when a ring is formed, R 101b , R101c Each represents an alkylene group having 1 to 6 carbon atoms. - represents a non-nucleophilic counter ion. 101d , R 101e , R 101f , R 101g is a hydrogen atom or R 101a , R 101b , R 101c It has the same definition as R 101d and R 101e , R 101d and R 101e and R 101f may form a ring, and when a ring is formed, R 101d and R 101e and R 101d and R 101e and R 101f represents an alkylene group having 3 to 10 carbon atoms, or a heteroaromatic ring having a nitrogen atom in the ring.

[0121] Above R 101a , R 101b , R 101c , R 101d , R 101e , R 101f , R 101gmay be the same or different, and specific examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl. Examples of alkenyl groups include vinyl, allyl, propenyl, butenyl, hexenyl, and cyclohexenyl. Examples of oxoalkyl groups include 2-oxocyclopentyl and 2-oxocyclohexyl groups, such as 2-oxopropyl, 2-cyclopentyl-2-oxoethyl, 2-cyclohexyl-2-oxoethyl, and 2-(4-methylcyclohexyl)-2-oxoethyl. Examples of the oxoalkenyl group include a 2-oxo-4-cyclohexenyl group and a 2-oxo-4-propenyl group. Examples of the aryl group include a phenyl group, a naphthyl group, and the like; alkoxyphenyl groups such as a p-methoxyphenyl group, a m-methoxyphenyl group, an o-methoxyphenyl group, an ethoxyphenyl group, a p-tert-butoxyphenyl group, and a m-tert-butoxyphenyl group; alkylphenyl groups such as a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, an ethylphenyl group, a 4-tert-butylphenyl group, a 4-butylphenyl group, and a dimethylphenyl group; alkylnaphthyl groups such as a methylnaphthyl group and an ethylnaphthyl group; alkoxynaphthyl groups such as a methoxynaphthyl group and an ethoxynaphthyl group; dialkylnaphthyl groups such as a dimethylnaphthyl group and a diethylnaphthyl group; and dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group. Examples of aralkyl groups include benzyl, phenylethyl, and phenethyl groups. Examples of aryloxoalkyl groups include 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl groups. -Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkyl sulfonates such as triflate, 1,1,1-trifluoroethanesulfonate, and nonafluorobutanesulfonate; aryl sulfonates such as tosylate, benzenesulfonate, 4-fluorobenzenesulfonate, and 1,2,3,4,5-pentafluorobenzenesulfonate; alkyl sulfonates such as mesylate and butanesulfonate; imido acids such as bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and bis(perfluorobutylsulfonyl)imide; methide acids such as tris(trifluoromethylsulfonyl)methide and tris(perfluoroethylsulfonyl)methide; and sulfonates substituted with fluorocarbons at the α-position as shown in the following formula (K-1) and sulfonates substituted with fluorocarbons at the α- and β-positions as shown in the following formula (K-2).

[0122] [ka]

[0123] [ka]

[0124] In formula (K-1), R 102K is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an acyl group, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aryloxy group. 103K is a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0125] Also, R 101d , R 101e , R 101f , R 101gIn the formula, the heteroaromatic ring having a nitrogen atom in the ring includes imidazole derivatives (e.g., imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, etc.), pyrazole derivatives, furazan derivatives, pyrroline derivatives (e.g., pyrroline, 2-methyl-1-pyrroline, etc.), pyrrolidine derivatives (e.g., pyrrolidine, N-methylpyrrolidine, pyrrolidinone, N-methylpyrrolidone, etc.), imidazoline derivatives, imidazolidine derivatives, pyridine derivatives (e.g., pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone, Examples include 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2-(1-ethylpropyl)pyridine, aminopyridine, dimethylaminopyridine, etc.), pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives, pyrazoline derivatives, pyrazolidine derivatives, piperidine derivatives, piperazine derivatives, morpholine derivatives, indole derivatives, isoindole derivatives, 1H-indazole derivatives, indoline derivatives, quinoline derivatives (e.g., quinoline, 3-quinolinecarbonitrile, etc.), isoquinoline derivatives, cinnoline derivatives, quinazoline derivatives, quinoxaline derivatives, phthalazine derivatives, purine derivatives, pteridine derivatives, carbazole derivatives, phenanthridine derivatives, acridine derivatives, phenazine derivatives, 1,10-phenanthroline derivatives, adenine derivatives, adenosine derivatives, guanine derivatives, guanosine derivatives, uracil derivatives, uridine derivatives, and the like.

[0126] (P1a-1) and (P1a-2) have the effect of both a photoacid generator and a thermal acid generator, while (P1a-3) acts only as a thermal acid generator.

[0127] [ka] (In the formula, R 102a , R102b R represents a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. 103 represents a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms. 104a , R 104b Each represents a 2-oxoalkyl group having 3 to 7 carbon atoms. - represents a non-nucleophilic counterion.)

[0128] Above R 102a , R 102b Specific examples of the alkyl group of R include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, and a cyclohexylmethyl group. 103 Examples of the alkylene group in R include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a 1,4-cyclohexylene group, a 1,2-cyclohexylene group, a 1,3-cyclopentylene group, a 1,4-cyclooctylene group, and a 1,4-cyclohexanedimethylene group. 104a , R 104b Examples of the 2-oxoalkyl group include a 2-oxopropyl group, a 2-oxocyclopentyl group, a 2-oxocyclohexyl group, and a 2-oxocycloheptyl group. - Examples of the groups are the same as those described for the formulae (P1a-1), (P1a-2) and (P1a-3).

[0129] [ka] (In the formula, R 105 , R 106 represents a linear, branched or cyclic alkyl group or halogenated alkyl group having 1 to 12 carbon atoms, an aryl group or halogenated aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms.

[0130] R 105 , R106 Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, an amyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a norbornyl group, and an adamantyl group. Examples of the halogenated alkyl group include a trifluoromethyl group, a 1,1,1-trifluoroethyl group, a 1,1,1-trichloroethyl group, and a nonafluorobutyl group. Examples of the aryl group include alkoxyphenyl groups such as a phenyl group, a p-methoxyphenyl group, a m-methoxyphenyl group, an o-methoxyphenyl group, an ethoxyphenyl group, a p-tert-butoxyphenyl group, and a m-tert-butoxyphenyl group, and alkylphenyl groups such as a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, an ethylphenyl group, a 4-tert-butylphenyl group, a 4-butylphenyl group, and a dimethylphenyl group. Examples of halogenated aryl groups include a fluorophenyl group, a chlorophenyl group, a 1,2,3,4,5-pentafluorophenyl group, etc. Examples of aralkyl groups include a benzyl group, a phenethyl group, etc.

[0131] [ka] (In the formula, R 107 , R 108 , R 109 R represents a linear, branched, or cyclic alkyl group or halogenated alkyl group having 1 to 12 carbon atoms, an aryl group or halogenated aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. 108 , R 109 may be bonded to each other to form a cyclic structure, and when a cyclic structure is formed, R 108 , R 109 R represents a linear or branched alkylene group having 1 to 6 carbon atoms. 105 is the same as that in equation (P2).

[0132] R 107 , R 108 , R 109The alkyl group, halogenated alkyl group, aryl group, halogenated aryl group, and aralkyl group are R 105 , R 106 The same groups as those explained in the above are exemplified. 108 , R 109 Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, and a hexylene group.

[0133] [ka] (In the formula, R 101a , R 101b is the same as above.)

[0134] [ka] (In the formula, R 110 R represents an arylene group having 6 to 10 carbon atoms, an alkylene group having 1 to 6 carbon atoms, or an alkenylene group having 2 to 6 carbon atoms, and some or all of the hydrogen atoms in these groups may be further substituted with a linear or branched alkyl group or alkoxy group having 1 to 4 carbon atoms, a nitro group, an acetyl group, or a phenyl group. 111 represents a linear, branched or substituted alkyl, alkenyl or alkoxyalkyl group having 1 to 8 carbon atoms, a phenyl group, or a naphthyl group, and some or all of the hydrogen atoms of these groups may be further substituted with an alkyl or alkoxy group having 1 to 4 carbon atoms; a phenyl group which may be substituted with an alkyl, alkoxy group, nitro or acetyl group having 1 to 4 carbon atoms; a heteroaromatic group having 3 to 5 carbon atoms; or a chlorine atom or a fluorine atom.

[0135] where R 110 Examples of the arylene group include a 1,2-phenylene group and a 1,8-naphthylene group, examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a phenylethylene group, and a norbornane-2,3-diyl group, and examples of the alkenylene group include a 1,2-vinylene group, a 1-phenyl-1,2-vinylene group, and a 5-norbornene-2,3-diyl group. 111The alkyl group of R 101a ~R 101c Examples of alkenyl groups include vinyl, 1-propenyl, allyl, 1-butenyl, 3-butenyl, isoprenyl, 1-pentenyl, 3-pentenyl, 4-pentenyl, dimethylallyl, 1-hexenyl, 3-hexenyl, 5-hexenyl, 1-heptenyl, 3-heptenyl, 6-heptenyl, and 7-octenyl groups; examples of alkoxyalkyl groups include methoxymethyl, ethoxymethyl, propoxymethyl, butoxymethyl, and the like. Examples of such alkyl groups include ethyl, pentyloxymethyl, hexyloxymethyl, heptyloxymethyl, methoxyethyl, ethoxyethyl, propoxyethyl, butoxyethyl, pentyloxyethyl, hexyloxyethyl, methoxypropyl, ethoxypropyl, propoxypropyl, butoxypropyl, methoxybutyl, ethoxybutyl, propoxybutyl, methoxypentyl, ethoxypentyl, methoxyhexyl, and methoxyheptyl groups.

[0136] Examples of the alkyl group having 1 to 4 carbon atoms which may be further substituted include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, and a tert-butoxy group. Examples of the phenyl group which may be substituted with an alkyl group, an alkoxy group, a nitro group, or an acetyl group having 1 to 4 carbon atoms include a phenyl group, a tolyl group, a p-tert-butoxyphenyl group, a p-acetylphenyl group, and a p-nitrophenyl group. Examples of the heteroaromatic group having 3 to 5 carbon atoms include a pyridyl group and a furyl group.

[0137] The above-mentioned other acid generators will be described in detail below. i. Examples of onium salts include tetramethylammonium trifluoromethanesulfonate, tetramethylammonium nonafluorobutanesulfonate, triethylammonium nonafluorobutanesulfonate, pyridinium nonafluorobutanesulfonate, triethylammonium camphorsulfonate, pyridinium camphorsulfonate, tetra-n-butylammonium nonafluorobutanesulfonate, tetraphenylammonium nonafluorobutanesulfonate, tetramethylammonium p-toluenesulfonate, diphenyliodonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, (p-tert-butoxyphenyl)phenyliodonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonate, tri tris(p-tert-butoxyphenyl)sulfonium, triphenylsulfonium p-toluenesulfonate, diphenylsulfonium p-toluenesulfonate, bis(p-tert-butoxyphenyl)phenylsulfonium p-toluenesulfonate, tris(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium butanesulfonate, trimethylsulfonium trifluoromethanesulfonate, p-toluene Trimethylsulfonium sulfonate, cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, cyclohexylmethyl(2-oxocyclohexyl)sulfonium p-toluenesulfonate, dimethylphenylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate, trinaphthylsulfonium trifluoromethanesulfonate,Examples of onium salts include (2-norbornyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, ethylene bis[methyl(2-oxocyclopentyl)sulfonium trifluoromethanesulfonate], 1,2'-naphthalenecarbonylmethyltetrahydrothiophenium triflate, triethylammonium nonaflate, tributylammonium nonaflate, tetraethylammonium nonaflate, tetrabutylammonium nonaflate, triethylammonium bis(trifluoromethylsulfonyl)imide, and triethylammonium tris(perfluoroethylsulfonyl)methide.

[0138] ii. Diazomethane derivatives include bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(xylenesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(cyclopentylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane, bis(n-propylsulfonyl)diazomethane, bis(isopropylsulfonyl)diazomethane, bis(tert-butylsulfonyl)diazomethane, Examples of diazomethane derivatives include bis(n-amylsulfonyl)diazomethane, bis(n-amylsulfonyl)diazomethane, bis(isoamylsulfonyl)diazomethane, bis(sec-amylsulfonyl)diazomethane, bis(tert-amylsulfonyl)diazomethane, 1-cyclohexylsulfonyl-1-(tert-butylsulfonyl)diazomethane, 1-cyclohexylsulfonyl-1-(tert-amylsulfonyl)diazomethane, and 1-tert-amylsulfonyl-1-(tert-butylsulfonyl)diazomethane.

[0139] iii. Glyoxime derivatives include bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-O-(p-toluenesulfonyl)-α-diphenylglyoxime, bis-O-(p-toluenesulfonyl)-α-dicyclohexylglyoxime, bis-O-(p-toluenesulfonyl)-2,3-pentanedione glyoxime, and bis-O-(p-toluenesulfonyl)-2-methyl-3,4-pentanedione. Glyoxime, bis-O-(n-butanesulfonyl)-α-dimethylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-dicyclohexylglyoxime, bis-O-(n-butanesulfonyl)-2,3-pentanedione glyoxime, bis-O-(n-butanesulfonyl)-2-methyl-3,4-pentanedione glyoxime, bis-O-(methane ...α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-dicyclohexylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-(n-butanesulfonyl)-α-diphenylglyoxime, bis-O-( Examples of glyoxime derivatives include bis-O-(trifluoromethanesulfonyl)-α-dimethylglyoxime, bis-O-(1,1,1-trifluoroethanesulfonyl)-α-dimethylglyoxime, bis-O-(tert-butanesulfonyl)-α-dimethylglyoxime, bis-O-(perfluorooctanesulfonyl)-α-dimethylglyoxime, bis-O-(cyclohexanesulfonyl)-α-dimethylglyoxime, bis-O-(benzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime, bis-O-(p-tert-butylbenzenesulfonyl)-α-dimethylglyoxime, bis-O-(xylenesulfonyl)-α-dimethylglyoxime, and bis-O-(camphorsulfonyl)-α-dimethylglyoxime.

[0140] iv. Examples of bissulfone derivatives include bisnaphthylsulfonylmethane, bistrifluoromethylsulfonylmethane, bismethylsulfonylmethane, bisethylsulfonylmethane, bispropylsulfonylmethane, bisisopropylsulfonylmethane, bis-p-toluenesulfonylmethane, and bisbenzenesulfonylmethane.

[0141] v Examples of sulfonate derivatives of N-hydroxyimide compounds include N-hydroxysuccinimide methanesulfonate ester, N-hydroxysuccinimide trifluoromethanesulfonate ester, N-hydroxysuccinimide ethanesulfonate ester, N-hydroxysuccinimide 1-propanesulfonate ester, N-hydroxysuccinimide 2-propanesulfonate ester, N-hydroxysuccinimide 1-pentanesulfonate ester, N-hydroxysuccinimide 1-octane sulfonate ester, N-hydroxysuccinimide p-toluenesulfonate ester, N-hydroxysuccinimide p-methoxybenzenesulfonate ester, N-hydroxysuccinimide 2-chloroethanesulfonate ester, N-hydroxysuccinimide benzenesulfonate ester, N-hydroxysuccinimide-2,4,6-trimethylbenzenesulfonate ester, N-hydroxysuccinimide 1-naphthalenesulfonate ester, N-hydroxysuccinimide 2-naphthalenesulfonate ester, and N-hydroxy-2-phenylsuccinimide metasulfonate. N-hydroxymaleimide methanesulfonate, N-hydroxymaleimide ethanesulfonate, N-hydroxy-2-phenylmaleimide methanesulfonate, N-hydroxyglutarimide methanesulfonate, N-hydroxyglutarimide benzenesulfonate, N-hydroxyphthalimide methanesulfonate, N-hydroxyphthalimide benzenesulfonate, N-hydroxyphthalimide trifluoromethanesulfonate, N-hydroxyphthalimide Examples of sulfonate ester derivatives of N-hydroxyimide compounds include N-hydroxyimide p-toluenesulfonate, N-hydroxynaphthalimide methanesulfonate, N-hydroxynaphthalimide benzenesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide methanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide trifluoromethanesulfonate, and N-hydroxy-5-norbornene-2,3-dicarboximide p-toluenesulfonate.

[0142] vi. Examples of β-ketosulfone derivatives include β-ketosulfone derivatives such as 2-cyclohexylcarbonyl-2-(p-toluenesulfonyl)propane and 2-isopropylcarbonyl-2-(p-toluenesulfonyl)propane.

[0143] vii. Examples of disulfone derivatives include diphenyl disulfone derivatives, dicyclohexyl disulfone derivatives, and the like.

[0144] viii. Examples of nitrobenzyl sulfonate derivatives include 2,6-dinitrobenzyl p-toluenesulfonate, 2,4-dinitrobenzyl p-toluenesulfonate, and the like.

[0145] ix. Examples of sulfonate derivatives include sulfonate derivatives such as 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene.

[0146] Among these, particularly preferred are triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium p-toluenesulfonate, tris(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate, trinaphthyl trifluoromethanesulfonate, Onium salts such as thiolsulfonium, cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, (2-norbornyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, 1,2'-naphthalenecarbonylmethyltetrahydrothiophenium triflate; bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane diazomethane derivatives such as bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; bissulfone derivatives such as bisnaphthylsulfonylmethane; N-hydroxysuccinimide methanesulfonate, ... Sulfonate ester derivatives of N-hydroxyimide compounds such as N-hydroxysuccinimide trifluoromethanesulfonate ester, N-hydroxysuccinimide 1-propanesulfonate ester, N-hydroxysuccinimide 2-propanesulfonate ester, N-hydroxysuccinimide 1-pentanesulfonate ester, N-hydroxysuccinimide p-toluenesulfonate ester, N-hydroxynaphthalimide methanesulfonate ester, and N-hydroxynaphthalimide benzenesulfonate ester are preferably used.

[0147] The acid generators may be used alone or in combination of two or more. The amount of acid generator added is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the base resin. If the amount is 0.05 parts by mass or more, the amount of acid generated is sufficient to allow the crosslinking reaction to proceed sufficiently, while if the amount is 50 parts by mass or less, there is little risk of the mixing phenomenon occurring due to the acid migrating to the upper resist layer.

[0148] [(E) Surfactant] The composition for forming a resist underlayer film of the present invention may contain a surfactant (E) to improve the coating properties in spin coating. Examples of the surfactant that can be used include those described in paragraphs (0142) to (0147) of JP-A No. 2009-269953. The amount of surfactant added is preferably 0.001 to 20 parts by mass, and more preferably 0.01 to 10 parts by mass, per 100 parts by mass of the base resin.

[0149] As described above, the composition for forming a resist underlayer film of the present invention preferably contains at least one selected from (D) an acid generator and (E) a surfactant. The composition for forming a resist underlayer film of the present invention can contain the additives described above for the purposes of accelerating a crosslinking reaction due to heat or the like, and improving the coatability, curability, planarization / filling properties in spin coating, and resolution in patterning in multilayer lithography.

[0150] The composition for forming a resist underlayer film of the present invention preferably provides a resist underlayer film that is resistant to an ammonia-containing aqueous hydrogen peroxide solution. Such a composition for forming a resist underlayer film can form a resist underlayer film that has good resistance to an alkaline aqueous hydrogen peroxide solution, and therefore can be applied to a wet etching process using an alkaline aqueous hydrogen peroxide solution.

[0151] Alkaline hydrogen peroxide solution is commonly used for cleaning semiconductor wafers. In particular, a mixture of 5 parts by weight of deionized water, 1 part by weight of 29% ammonia water, and 1 part by weight of 30% hydrogen peroxide solution is called SC1 (Standard Clean-1) and is a standard chemical solution for cleaning and removing organic impurities and fine particles from wafer surfaces. In addition, alkaline hydrogen peroxide solution can be used to strip or etch some metals and metal compounds, as well as silicon-containing resist intermediate films designed for wet stripping. The composition of the alkaline hydrogen peroxide solution used in these processes is not particularly limited, but it is typically a mixture of deionized water, hydrogen peroxide, and ammonia. In this case, the hydrogen peroxide concentration is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, and the ammonia concentration is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight. The treatment temperature is preferably 0 to 90°C, more preferably 20 to 80°C.

[0152] Here, we will explain the alkaline hydrogen peroxide resistance test for resist underlayer films. First, a resist underlayer film material is formed on a silicon wafer cut into 3 cm squares to a film thickness of approximately 100 nm according to the film formation conditions described below. This wafer piece is immersed in 1.0 mass % hydrogen peroxide solution containing 0.5 mass % ammonia at 70°C for 5 minutes, and then rinsed with deionized water. The resist underlayer film can then be visually inspected for peeling from the wafer. If part or all of the resist underlayer film peels off, exposing the silicon wafer surface, the resist underlayer film used in the test is deemed to have insufficient alkaline hydrogen peroxide resistance.

[0153] That is, it is preferable that the resist underlayer film formed from the composition for forming a resist underlayer film of the present invention is one in which peeling of the resist underlayer film is not observed when a silicon substrate on which the resist underlayer film has been formed is immersed in a 1.0 mass % hydrogen peroxide solution containing 0.5 mass % ammonia at 70°C for 5 minutes.

[0154] In the present invention, the thickness of the resist underlayer film is appropriately selected, but is preferably 5 to 20,000 nm, particularly 50 to 15,000 nm. In the case of a resist underlayer film for a three-layer resist process, a silicon-containing resist intermediate film or a silicon-free resist top layer film can be formed thereon. In the case of a resist underlayer film for a two-layer resist process, a silicon-containing resist top layer film or a silicon-free resist top layer film can be formed thereon.

[0155] (Method for forming a resist underlayer film) The present invention provides a method for forming a resist underlayer film, which comprises coating the above-mentioned composition for forming a resist underlayer film on a substrate to be processed, and heat-treating the composition for forming a resist underlayer film at a temperature of 100°C or higher and 300°C or lower for 10 seconds to 600 seconds, thereby forming a cured film. This method for forming a resist underlayer film can form a resist underlayer film that has good alkaline hydrogen peroxide resistance, excellent filling / planarization properties, and excellent dry etching properties. Furthermore, by appropriately adjusting the baking temperature and time within the above ranges, it is possible to obtain planarization / filling properties and curing properties suitable for the application.

[0156] In the method for forming a resist underlayer film of the present invention, the above-mentioned composition for forming a resist underlayer film is coated onto a substrate to be processed by a method such as spin coating, followed by evaporation of the solvent and baking to prevent mixing with the resist top layer film or resist intermediate film or to promote a crosslinking reaction. By using a method such as spin coating in this manner, good filling / planarization properties can be obtained.

[0157] Baking is performed at a temperature range of 100°C to 500°C, preferably 100°C to 300°C, and more preferably 150°C to 300°C, for 10 to 600 seconds, preferably 10 to 300 seconds. By appropriately adjusting the baking temperature and time within the above ranges, planarization, embedding, and curing characteristics suitable for the application can be obtained. A baking temperature of 100°C or higher ensures sufficient curing, eliminating the risk of mixing with the upper layer or intermediate film. A baking temperature of 300°C or lower prevents significant thermal decomposition of the base resin, eliminating the risk of film thickness reduction or unevenness of the film surface.

[0158] The resist underlayer film forming method of the present invention is also preferably used with a substrate having a structure or step having a height of 30 nm or more as the substrate to be processed, and is particularly useful when forming a void-free planarizing organic film on a substrate having a structure or step having a height of 30 nm or more.

[0159] (Pattern formation method) The present invention provides a pattern formation method using the above-mentioned composition for forming a resist underlayer film. The pattern formation method of the present invention is suitable for use in multilayer resist processes such as a silicon-containing two-layer resist process, a three-layer resist process using a silicon-containing intermediate layer film, a four-layer resist process using a silicon-containing intermediate layer film and an organic antireflective coating, or a silicon-free two-layer resist process.

[0160] That is, in the present invention, a pattern formation method by a two-layer resist process is a method for forming a pattern on a substrate to be processed, (I-1) a step of applying the composition for forming a resist underlayer film described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a composition for forming a resist upper layer film; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the resist underlayer film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; The present invention provides a pattern forming method comprising the steps of:

[0161] Further, in the present invention, a pattern formation method by a three-layer resist process is a method for forming a pattern on a substrate to be processed, comprising the steps of: (II-1) a step of applying the composition for forming a resist underlayer film described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (II-2) forming a silicon atom-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon atom-containing resist intermediate film using a composition for forming a resist upper layer film; (II-4) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (II-5) a step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the silicon atom-containing resist intermediate film to which the pattern has been transferred as a mask; The present invention provides a pattern forming method comprising the steps of:

[0162] Further, in the present invention, a pattern formation method by a four-layer resist process is a method for forming a pattern on a substrate to be processed, comprising the steps of: (III-1) a step of applying the composition for forming a resist underlayer film described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (III-2) forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film; (III-3) forming an organic anti-reflective coating on the inorganic hard mask; (III-4) forming a resist upper layer film on the organic antireflective film using a composition for forming a resist upper layer film; (III-5) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (III-6) a step of transferring a pattern to the organic anti-reflective film and the inorganic hard mask by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (III-7) a step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask to which the pattern has been transferred as a mask; The present invention provides a pattern forming method comprising the steps of:

[0163] The pattern forming method of the present invention will be described below using as an example a three-layer resist process using a resist interlayer containing silicon atoms (silicon-containing resist interlayer), but is not limited to this.

[0164] In this case, a resist underlayer film is formed on a substrate to be processed using the above-mentioned composition for forming a resist underlayer film, a resist intermediate film is formed on the resist underlayer film using a resist intermediate film material containing silicon atoms, a resist upper layer film is formed on the resist intermediate film using a photoresist material to form a multilayer resist film, the pattern circuit area of ​​the resist upper layer film is exposed (pattern exposed) and then developed with a developer to form a pattern in the resist upper layer film, the resist upper layer film on which the pattern has been formed is used as a mask to etch the resist intermediate film to transfer the pattern, the resist underlayer film is used as a mask to etch the resist intermediate film to transfer the pattern, and further the substrate to be processed is processed using the resist underlayer film on which the pattern has been transferred as a mask to form a pattern on the substrate to be processed.

[0165] In a three-layer resist process, the resist underlayer film can be formed by applying the above-described resist underlayer film material to a substrate to be processed using a method such as spin coating, followed by evaporation of the solvent and baking to prevent mixing with the resist toplayer film or resist middle film or to promote a crosslinking reaction. By using a method such as spin coating, excellent embedding characteristics can be obtained. The formation of this underlayer film can be carried out using the resist underlayer film formation method of the present invention described above.

[0166] A resist intermediate film containing silicon atoms exhibits resistance to etching by oxygen gas or hydrogen gas, and therefore, as described above, etching of the resist underlayer film using the resist intermediate film as a mask is preferably carried out using an etching gas mainly containing oxygen gas or hydrogen gas.

[0167] In a three-layer resist process, a polysilsesquioxane-based interlayer is preferably used as the silicon-containing resist interlayer. Polysilsesquioxane-based interlayers are easily imparted with anti-reflection properties, which can suppress reflected light during pattern exposure of the resist top layer, resulting in excellent resolution. For 193 nm exposure in particular, using a material containing many aromatic groups as the resist bottom layer increases the k value and substrate reflection, but suppressing reflection with a resist interlayer can reduce substrate reflection to 0.5% or less. For 248 nm and 157 nm exposure, anthracene is preferred, while for 193 nm exposure, polysilsesquioxane is preferred, which has pendant light-absorbing groups containing phenyl groups or silicon-silicon bonds and is crosslinked by acid or heat.

[0168] In this case, forming a silicon-containing resist intermediate film by spin coating is easier and more cost-effective than forming it by CVD.

[0169] The resist top layer film in the three-layer resist process may be either positive or negative, and the same photoresist compositions as those commonly used can be used. When forming a single-layer resist top layer film using the photoresist composition, a spin coating method is preferably used, as in the case of forming the resist underlayer film. After spin coating the photoresist composition, pre-baking is performed, preferably at 60 to 180°C for 10 to 300 seconds. Thereafter, exposure, post-exposure baking (PEB), and development are performed according to conventional methods to obtain a resist pattern. The thickness of the resist top layer film is not particularly limited, but is preferably 30 to 500 nm, more preferably 50 to 400 nm. Examples of exposure light include high energy rays with a wavelength of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, and X-rays.

[0170] Next, etching is performed using the obtained resist pattern as a mask. In the three-layer resist process, etching of the resist intermediate film is performed using a fluorocarbon-based gas as a mask. Next, etching of the resist underlayer film is performed using oxygen gas or hydrogen gas as a mask.

[0171] The next step, etching of the substrate to be processed, can also be done using standard methods; for example, if the substrate is made of SiO2, SiN, or a silica-based low-k dielectric insulating film, etching is done primarily with fluorocarbon-based gases, while for p-Si, Al, or W, etching is done primarily with chlorine- or bromine-based gases. If the substrate is etched with fluorocarbon-based gases, the resist interlayer (silicon-containing resist interlayer) in the three-layer resist process is stripped at the same time as the substrate is processed. If the substrate is etched with chlorine- or bromine-based gases, the silicon-containing resist interlayer must be stripped separately by dry etching using fluorocarbon-based gases after the substrate is processed.

[0172] The substrate to be processed has a layer to be processed formed on it. The substrate is not particularly limited, and may be made of a material different from the layer to be processed, such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, or Al. The layer to be processed may be a low-k film or a stopper film thereof, such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, TiN, W-Si, Al, Cu, or Al-Si, and is typically formed to a thickness of 50 to 10,000 nm, and particularly 100 to 5,000 nm.

[0173] Here, if the pattern forming method of the present invention is applied, in addition to the above-mentioned general processing processes, it becomes possible to establish various special processing processes, and this has great industrial value.

[0174] First, as described above, dry etching is generally required to strip the silicon-containing resist intermediate film, but in the pattern formation method of the present invention, because the resist underlayer film is resistant to alkaline hydrogen peroxide, wet stripping of only the silicon-containing resist intermediate film using alkaline hydrogen peroxide is also an option. That is, in the pattern formation method using the three-layer resist process of the present invention, after the above step (II-6), a step of removing the resist intermediate film to which the pattern has been transferred by wet etching using alkaline hydrogen peroxide may be added.

[0175] Furthermore, when the substrate to be processed is made of W, TiN, etc., wet etching of the substrate with alkaline hydrogen peroxide water can also be an option when the pattern formation method of the present invention is applied. That is, in the pattern formation method using the two-layer, three-layer, or four-layer resist process of the present invention, after the above step (I-4), step (II-6), or step (III-7), a step of transferring a pattern to the substrate to be processed by wet etching with alkaline hydrogen peroxide water may be added, using the resist underlayer film to which the pattern has been transferred as a mask.

[0176] In one example of such a process, a resist underlayer film is first formed on a substrate to be processed, and then a resist intermediate film is formed thereon as necessary, followed by a resist upper layer film. The resist upper layer film is then patterned by a conventional method, and the pattern is then transferred to the resist underlayer film by etching. Finally, the substrate to be processed can be patterned by wet etching using the resist underlayer film as a mask.

[0177] In the present invention, after the step (I-4), the step (II-6), or the step (III-7), a step of transferring a pattern to the workpiece substrate by dry etching using the resist underlayer film to which the pattern has been transferred as a mask may be further added.

[0178] Furthermore, in the pattern formation method using the two-layer, three-layer, or four-layer resist process of the present invention, after the above-mentioned step (I-4), step (II-6), or step (III-7), a step of patterning the substrate to be processed by ion implantation using the resist underlayer film to which the pattern has been transferred as a mask may be added. In this case, after the step of patterning the substrate to be processed by ion implantation, a step of removing the resist intermediate film to which the pattern has been transferred by wet etching using alkaline hydrogen peroxide water may be added.

[0179] The pattern forming method of the present invention is also suitable for processing a stepped substrate having structures or steps with a height of 30 nm or more. An example of such a process will be described below.

[0180] First, a resist underlayer film is formed on a stepped substrate, followed by filling and planarization, and if necessary, a resist intermediate film is formed, followed by a resist toplayer film. Next, the resist toplayer film is patterned using conventional methods, and the pattern is subsequently transferred to the resist underlayer film by etching. Next, the substrate can be patterned by ion implantation using the resist underlayer film as a mask. The remaining resist intermediate film can be removed by either dry etching or wet etching, as required. Finally, the resist underlayer film can be removed by dry etching.

[0181] In this case, it is preferable to use a composition for forming a resist underlayer film having a dry etching rate higher than that of the resist upper layer film. Use of such a resist underlayer film material (i.e., if the dry etching rate of the resist underlayer film to be formed is high) makes it possible to remove the resist underlayer film without leaving any residue by dry etching even in areas that are generally difficult to remove, such as corners of steps on the substrate, which is more preferable.

[0182] Furthermore, in the pattern formation method of the present invention, at least a resist underlayer film is formed on a substrate to be processed using the composition for forming a resist underlayer film, an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the resist underlayer film, a resist upper layer film is formed on the inorganic hard mask intermediate film using a photoresist material, a pattern circuit region of the resist upper layer film is exposed to light and then developed with a developer to form a pattern in the resist upper layer film, the inorganic hard mask intermediate film is etched using the resist upper layer film on which the pattern has been formed as a mask to transfer the pattern, the resist underlayer film is etched using the inorganic hard mask intermediate film on which the pattern has been transferred as a mask to transfer the pattern, and the substrate to be processed is processed using the resist underlayer film on which the pattern has been transferred as a mask to form a pattern on the substrate to be processed.

[0183] As described above, when an inorganic hard mask intermediate film is formed on a resist underlayer film, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) is formed by a CVD method, an ALD method, or the like. Methods for forming nitride films are described in JP 2002-334869 A and WO 2004 / 066377 A. The thickness of the inorganic hard mask is 5 to 200 nm, preferably 10 to 100 nm, and among these, a SiON film is most preferably used because of its high anti-reflection effect.

[0184] The present invention can also be suitably applied to a four-layer resist process using an organic antireflective film. In this case, at least a resist underlayer film is formed on a substrate to be processed using the above-mentioned composition for forming a resist underlayer film, an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the resist underlayer film, an organic antireflective film is formed on the inorganic hard mask intermediate film, a resist upper layer film is formed on the organic antireflective film using a photoresist material, the pattern circuit region of the resist upper layer film is exposed to light, and then developed with a developer to form a pattern on the resist upper layer film, the organic antireflective film and the inorganic hard mask intermediate film are etched using the resist upper layer film with the pattern formed as a mask to transfer the pattern, the resist underlayer film is etched using the inorganic hard mask intermediate film with the pattern transferred as a mask to transfer the pattern, and the substrate to be processed is processed using the resist underlayer film with the pattern transferred as a mask to form a pattern on the substrate to be processed.

[0185] A photoresist film can be formed as a resist top layer on top of the resist interlayer, or, as mentioned above, an organic anti-reflective coating (BARC) can be formed on top of the resist interlayer by spin coating, and then a photoresist film can be formed on top of that. When a SiON film is used as the resist interlayer, the two-layer anti-reflective coating of the SiON film and the BARC film can suppress reflection even in immersion lithography with a high NA exceeding 1.0. Another advantage of forming a BARC is that it reduces the footing of the photoresist pattern directly above the SiON.

[0186] An example of a three-layer resist process is specifically shown below with reference to FIG. In the case of a three-layer resist process, as shown in FIG. 1(A), a resist underlayer film 3 is formed on a processable layer 2 stacked on a substrate 1, then a resist intermediate film 4 is formed, and a resist upper layer film 5 is formed on top of that.

[0187] Next, as shown in FIG. 1(B), a desired portion 6 of the resist top layer is exposed, followed by PEB (post-exposure bake) and development to form a resist pattern 5a (FIG. 1(C)). Using the resulting resist pattern 5a as a mask, the resist intermediate film 4 is etched using a CF-based gas to form a resist intermediate film pattern 4a (FIG. 1(D)). After removing the resist pattern 5a, the resist underlayer film 3 is etched with oxygen-based or hydrogen-based plasma using the resulting resist intermediate film pattern 4a as a mask to form a resist underlayer film pattern 3a (FIG. 1(E)). After further removing the resist intermediate film pattern 4a, the workpiece layer 2 is etched using the resist underlayer film pattern 3a as a mask to form a pattern 2a (FIG. 1(F)).

[0188] When an inorganic hard mask intermediate film is used, the resist intermediate film 4 is the inorganic hard mask intermediate film, and when a BARC is laid down, a BARC layer is provided between the resist intermediate film 4 and the resist top layer film 5. The BARC may be etched prior to and subsequently to the etching of the resist intermediate film 4, or the BARC alone may be etched and then the resist intermediate film 4 may be etched by changing the etching equipment. The present invention will be described in detail below, but the present invention is not limited thereto. [Example]

[0189] The polydispersity (Mw / Mn) was calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene.

[0190] Polymer compounds (A1) to (A6) synthesized in the synthesis examples and polymer compounds (R1) to (R4) for comparison are shown below. [ka]

[0191] [Synthesis Example 1] Synthesis of polymer compound (A1) 38.9 g of propylene glycol monomethyl ether acetate (PGMEA) was heated and stirred at 80°C under a nitrogen atmosphere. To this was added a mixture of 29.7 g of glycidyl methacrylate, 8.9 g of tert-butyl acrylate, 11.3 g of benzyl acrylate, and 38.9 g of PGMEA, and a mixture of 4.0 g of dimethyl 2,2-azobis(2-methylpropionate) and 38.9 g of PGMEA, simultaneously and separately, over a period of 4 hours. After heating and stirring for an additional 20 hours, the mixture was cooled to room temperature to obtain a PGMEA solution of the target polymer compound (A1). Analysis revealed that the weight-average molecular weight (Mw) of polymer compound (A1) was 9,500 and the polydispersity (Mw / Mn) was 1.95.

[0192] [Synthesis Examples 2 to 9] Synthesis of polymer compounds (A2) to (A6) and comparative polymer compounds (R1) to (R3) Except for changing the type and molar ratio of the raw material monomers used according to the structure of each polymer compound, PGMEA solutions of polymer compounds (A2) to (A6) and comparative polymer compounds (R1) to (R3) were obtained in the same manner as in Synthesis Example 1. The synthesis method for (R4) was as follows.

[0193] [Synthesis Example 10] Synthesis of comparative polymer compound (R4). [ka] 78.8 g of 2,7-dipropargyloxynaphthalene, 21.6 g of 37% formalin solution, and 250 g of 1,2-dichloroethane were mixed under a nitrogen atmosphere at 70°C to form a homogeneous solution. 5 g of methanesulfonic acid was then slowly added and the mixture was stirred at 80°C for 12 hours. After cooling to room temperature, 500 g of methyl isobutyl ketone was added, and the organic layer was washed five times with 200 g of pure water. The organic layer was then evaporated to dryness under reduced pressure. 300 mL of THF was added to the residue, and the polymer was reprecipitated with 2,000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain polymer compound (R4).

[0194] [Preparation of Compositions for Forming Resist Underlayer Films (UDL-1 to 14, Comparative Examples UDL-1 to 8)] Polymeric compounds (A1)-(A6) within the scope of component (A) of the present invention and (R1)-(R4) outside the scope, crosslinkers (B1)-(B7) within the scope of component (B) of the present invention and (X1), (B8), and (B9) outside the scope, and acid generators (AG1)-(AG3) were dissolved in a solvent containing 0.05% by mass of PF-6320 (OMNOVA, purified in-house) as a surfactant in the proportions shown in Table 1, and the resulting solution was filtered through a 0.1 μm fluororesin filter to prepare resist underlayer film-forming compositions (UDL-1-14 and Comparative Examples UDL-1-8). In Table 1, PGMEA stands for propylene glycol monomethyl ether acetate.

[0195] [Table 1]

[0196] In Table 1 above, the details of crosslinking agents (B1) to (B9) are as follows. (B1) to (B7) are within the scope of formula (B-1) of the present invention. (B8) and (B9) are outside the scope. The Mw and Mw / Mn measured by GPC (eluent: THF) for each compound are shown. [ka]

[0197] [Synthesis of crosslinking agents (B1) to (B8)]

[0198] In Table 1 above, the crosslinking agent (B1) was synthesized as follows. Synthesis of crosslinker (B1) [ka] Under a nitrogen atmosphere, 10.0 g (39.2 mmol) of monomethyl diglycidyl isocyanurate (Shikoku Kasei Co., Ltd.), 13.5 g (78.4 mmol) of 1-naphthoic acid, and 50.0 g of PGME (1-methoxypropanol) were added to a three-neck flask equipped with a thermometer and reflux condenser. The internal temperature was raised to 80 °C to form a homogeneous solution, after which 0.89 g (3.9 mmol) of benzyltriethylammonium chloride was added and the reaction was carried out for 6 hours in an oil bath at 120 °C. After the reaction was stopped, the solution was diluted with 200 ml of toluene, transferred to a separatory funnel, and washed five times with 50 g of 3% aqueous NaHCO3 solution, 50 g of 3% aqueous nitric acid solution, and 50 ml of ultrapure water. The organic phase was recovered and concentrated to dryness to obtain crosslinker (B1). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B1): Mw=620, Mw / Mn=1.01.

[0199] Similarly, for (B2) to (B4), (B6), and (B8), crosslinking agents (B2) to (B4), (B6), and (B8) were obtained in the same manner as for (B1), only by using epoxy compounds and carboxylic acid compounds corresponding to the structural formulas as raw materials.

[0200] Synthesis of crosslinker (B5) [ka] Under a nitrogen atmosphere, 10.0 g (35.6 mmol) of monoallyl diglycidyl isocyanurate (Shikoku Kasei Co., Ltd.), 12.2 g (71.1 mmol) of 2-naphthoic acid, and 50.0 g of PGME (1-methoxypropanol) were added to a three-neck flask equipped with a thermometer and reflux condenser. The internal temperature was raised to 80 °C to form a homogeneous solution, after which 0.81 g (3.6 mmol) of benzyltriethylammonium chloride was added and the reaction was carried out in an oil bath at 120 °C for 6 hours. After the reaction was stopped, the solution was diluted with 200 mL of toluene, transferred to a separatory funnel, and washed four times with 50 mL of 3% aqueous NaHCO3 solution and 50 mL of ultrapure water. The organic phase was collected, concentrated to dryness, and then 60 g of DMF (dimethylformamide) was added to form a homogeneous solution. The DMF solution recovered above and 14.4 g (142.2 mmol) of triethylamine were added to a three-neck flask equipped with a thermometer and reflux condenser under a nitrogen atmosphere and made into a homogeneous solution at room temperature. After the internal temperature was raised to 40°C to make a homogeneous solution, 9.7 g (106.6 mmol) of acrylic acid chloride was slowly added and the reaction was carried out in an oil bath at 40°C for 6 hours. After the reaction was stopped, 20 g of water was added to quench the reaction. The mixture was diluted with 200 ml of MIBK (methyl isobutyl ketone), transferred to a separatory funnel, and washed twice with 50 g of 3% aqueous NaHCO3 solution, twice with 50 g of 3% aqueous nitric acid solution, and five times with 50 ml of ultrapure water. The organic phase was recovered and concentrated to dryness to obtain crosslinker (B5). The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, yielding the following results. (B5): Mw=750, Mw / Mn=1.02.

[0201] Synthesis of crosslinker (B7) [ka] Under a nitrogen atmosphere, 10.0 g (33.6 mmol) of triglycidyl isocyanurate (Nissan Chemicals), 22.4 g (100.6 mmol) of 9-anthracenecarboxylic acid, and 70.0 g of PGME (1-methoxypropanol) were added to a three-neck flask equipped with a thermometer and reflux condenser. The internal temperature was raised to 80 °C to form a homogeneous solution, after which 1.15 g (5.0 mmol) of benzyltriethylammonium chloride was added and the reaction was carried out for 6 hours in an oil bath at 120 °C. After the reaction was stopped, the mixture was diluted with 200 mL of toluene, transferred to a separatory funnel, and washed four times with 50 mL of 3% aqueous NaHCO3 solution and 50 mL of ultrapure water. The organic phase was collected, concentrated to dryness, and then 80 g of DMF (dimethylformamide) was added to form a homogeneous solution. The DMF solution recovered above and 13.3 g (167.6 mmol) of pyridine were added to a three-neck flask equipped with a thermometer and reflux condenser under a nitrogen atmosphere and made into a homogeneous solution at room temperature. After the internal temperature was raised to 40 °C to make a homogeneous solution, 13.7 g (134.1 mmol) of acetic anhydride was slowly added and the reaction was carried out in an oil bath at 40 °C for 6 hours. After the reaction was stopped, 20 g of water was added to quench the reaction. The mixture was diluted with 200 ml of MIBK (methyl isobutyl ketone), transferred to a separatory funnel, and washed twice with 50 g of 3% aqueous NaHCO3 solution, twice with 50 g of 3% aqueous nitric acid solution, and five times with 50 ml of ultrapure water. The organic phase was recovered and concentrated to dryness to obtain crosslinker (B7). The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, yielding the following results. (B7): Mw=1150, Mw / Mn=1.03.

[0202] [Synthesis of comparative crosslinker (B9)] [ka] Under a nitrogen atmosphere, 10.0 g of HP-4700 (DIC, epoxy equivalent weight 165 g / eq.) (corresponding to 60.6 mmol of epoxy groups), 13.5 g (60.6 mmol) of 9-anthracenecarboxylic acid, and 70.0 g of PGME (1-methoxypropanol) were added to a three-neck flask equipped with a thermometer and reflux condenser. The internal temperature was raised to 80 °C to form a homogeneous solution, after which 0.69 g (3.0 mmol) of benzyltriethylammonium chloride was added and the reaction was carried out in an oil bath at 120 °C for 6 hours. After the reaction was stopped, the mixture was diluted with 200 mL of MIBK, transferred to a separatory funnel, and washed four times with 50 g of 3% NaHCO3 aqueous solution and 50 mL of ultrapure water. The organic phase was collected, concentrated to dryness, and then 80 g of DMF (dimethylformamide) was added to form a homogeneous solution. The DMF solution recovered above and 6.2 g (78.8 mmol) of pyridine were added to a three-neck flask equipped with a thermometer and reflux condenser under a nitrogen atmosphere and made into a homogeneous solution at room temperature. After the internal temperature was raised to 40°C to make a homogeneous solution, 7.4 g (72.7 mmol) of acetic anhydride was slowly added and the reaction was carried out in an oil bath at 40°C for 6 hours. After the reaction was stopped, 20 g of water was added to quench the reaction. The mixture was diluted with 200 ml of MIBK and transferred to a separatory funnel. The mixture was washed twice with 50 g of 3% aqueous NaHCO3 solution, twice with 50 g of 3% aqueous nitric acid solution, and five times with 50 ml of ultrapure water. The organic phase was recovered and concentrated to dryness to obtain crosslinker (B9). The weight-average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, yielding the following results. (B9): Mw=1930, Mw / Mn=1.27.

[0203] In Table 1 above, the details of the acid generators (AG1) to (AG3) and the comparative crosslinking agent (X1) are as follows: [ka]

[0204] [ka]

[0205] [Solvent Resistance and Optical Constant Measurements (Examples 1-1 to 1-14, Comparative Examples 1-1 to 1-8)] The resist underlayer film materials (UDL-1 to 14, comparative examples UDL-1 to 8) prepared above were coated onto silicon substrates and baked for 60 seconds at the temperatures listed in Table 2. The film thickness was then measured, PGMEA solvent was dispensed onto the substrate, the substrate was left for 30 seconds, spin-dried, and baked at 100°C for 60 seconds to evaporate the PGMEA solvent. The film thickness was then measured again, and the difference in film thickness before and after PGMEA treatment was determined to evaluate solvent resistance. The optical constants (refractive index n, extinction coefficient k) of the deposited resist underlayer films at a wavelength of 193 nm, as determined using a JA Woollam variable angle spectroscopic ellipsometer (VASE), are also listed in Table 2 below.

[0206] [Table 2]

[0207] It was found that all of the resist underlayer film compositions (UDL-1 to 14) of the present invention have good film-forming properties, undergo almost no film loss due to solvent treatment, and produce films with good solvent resistance. Furthermore, while the optical constants depend on factors such as the film thickness and the type of overlying film, they generally have an n value of 1.5 to 1.9 and a k value of 0.1 to 0.5, which allows for considerable suppression of reflected light from the substrate and makes them suitable for use as underlayer films for photoresist patterning. In the above examples, the optical constants were all within suitable ranges, making them suitable for use as underlayer films for photoresist patterning.

[0208] [Dry etching test using N2 / H2-based gas (Examples 2-1 to 2-14, Comparative Examples 2-1 to 2-9)] The resist underlayer film formed as above and the resist upper layer film formed as below were subjected to a dry etching test using an N2 / H2-based gas. The results are shown in Table 4.

[0209] The resist top layer material (ArF photoresist) used for patterning was prepared by dissolving a polymer (resin) designated as ArF single-layer resist polymer 1, an acid generator PAG1, and a base compound amine 1 in a solvent containing 0.1 mass% FC-4430 (manufactured by Sumitomo 3M Limited) in the proportions shown in Table 3, and filtering the solution through a 0.1 μm fluororesin filter.

[0210] [Table 3]

[0211] The ArF single layer resist polymer 1, PAG1, and amine 1 used are shown below.

[0212] [ka]

[0213] [ka]

[0214] The resist top layer film material (PR-1) prepared above was applied onto a silicon substrate and baked at 120° C. for 60 seconds to form a photoresist film with a thickness of approximately 200 nm.

[0215] The dry etching test using N2 / H2 gas was carried out under the following conditions.

[0216] Etching conditions Chamber pressure 2.7Pa RF power 1,000W N2 gas flow rate: 500 mL / min H2 gas flow rate: 30 mL / min Time 20sec

[0217] Table 4 shows the dry etching rate calculated by dividing the difference in film thickness before and after dry etching measured using a Telius etching system manufactured by Tokyo Electron by the etching time.

[0218] [Table 4]

[0219] The above results show that the resist underlayer film compositions (UL-1 to UL-14) of the present invention all have higher dry etching rates than the resist toplayer film (Comparative Example 2-9). Compared to Comparative Example 2-1, which does not contain the crosslinking agents (B1) to (B6) of the present invention having specific structures, the etching rates are significantly improved. This shows that the resist underlayer film-forming composition of the present invention is preferable, particularly in a processing process that includes removing the resist underlayer film by dry etching after substrate processing, because it can suppress residues after removing the resist underlayer film. In Comparative Example 2-5, the dry etching rate was lower than that of the resist top layer film, and it was found that residues were likely to be generated when the resist bottom layer film was removed by dry etching. In Comparative Example 2-4 (Comparative Example UDL-4), the etching rate was presumably lowered because a polymer compound (R3) containing an anthracene ring as an ultraviolet absorbing group in the repeating unit structure was used.

[0220] [Evaluation of Filling Characteristics (Examples 3-1 to 3-14, Comparative Examples 3-1 to 3-8)] Each of the resist underlayer film-forming compositions was applied to a SiO2 wafer substrate with a dense hole pattern (hole diameter 0.16 μm, hole depth 0.50 μm, center-to-center distance between adjacent holes 0.32 μm) and baked at 250°C for 60 seconds to form a resist underlayer film. The substrate used was a base substrate 7 (SiO2 wafer substrate) with a dense hole pattern as shown in Figure 2(G) (overhead view) and (H) (cross-sectional view). The cross-sectional shape of each wafer substrate was observed using a scanning electron microscope (SEM) to confirm whether the holes were filled with the resist underlayer film without voids. The results are shown in Table 5. When a resist underlayer film material with poor filling properties was used, voids were generated within the holes in this evaluation. When a resist underlayer film material with good filling properties was used, the holes were filled with the resist underlayer film 8 without voids, as shown in Figure 2(I).

[0221] [Table 5]

[0222] From the above results, it was found that in Examples 3-1 to 3-14, which used resist underlayer film-forming compositions (UDL-1 to 14) that employed crosslinkers (B1) to (B7) within the range of formula (B-1) of the present invention, hole patterns could be filled without voids. On the other hand, voids were observed in Comparative Example 3-1, which used a resist underlayer film-forming composition that did not contain a crosslinker (Comparative Example UDL-1), and in Comparative Examples 3-6 to 3-8, which used resist underlayer film-forming compositions that contained crosslinkers outside the range of formula (B-1) of the present invention (Comparative Examples UDL-6, UDL-7, and UDL-8). This suggests that the crosslinker with a specific structure of the present invention contributes to the fluidity of the resist underlayer film-forming composition. It is speculated that the reason for this is that crosslinker (B8) has hydroxyl groups and is highly curable, which reduces the thermal fluidity during baking, while crosslinker (B9) has many aromatic structures, which reduces the fluidity of the composition. When polymer compounds (R1) to (R4) outside the scope of formula (A-1) of the present invention were used as component (A), voids were also observed in combination with crosslinkers (B1) to (B3) within the scope of formula (B-1) of the present invention as component B (Comparative examples UDL-2 to UDL-5 for resist underlayer film formation). This is presumably due to the poor fluidity of polymer compounds (R2) to (R4), which resulted in poor embedding ability. Although the detailed mechanism of the above results is unclear, it is presumed that the fluidity of the polymer compound is improved by having the structural unit (a1) represented by formula (A-1) and, in addition, at least one of the structural units (a2) represented by formulas (A-2) to (A-4), and that the combination of this polymer compound with a crosslinker having a specific structure represented by formula (B-1) enables the formation of a resist underlayer film with excellent embedding ability.

[0223] [Evaluation of Planarization Characteristics (Examples 4-1 to 4-14, Comparative Examples 4-1 to 4-8)] Each of the resist underlayer film-forming compositions was applied to a base substrate 9 (SiO2 wafer substrate) having a giant isolated trench pattern (Figure 3(J), trench width 10 μm, trench depth 0.1 μm) and baked at 250°C. After that, the difference in film thickness between the trench portion and the non-trench portion of the resist underlayer film 10 (delta 10 in Figure 3(K)) was observed using an atomic force microscope (AFM). The results are shown in Table 6. In this evaluation, the smaller the difference in film thickness, the better the planarization characteristics.

[0224] [Table 6]

[0225] From the above results, it was found that the resist underlayer film-forming compositions of the present invention (UDL-1 to 14) have a smaller difference in film thickness between the trench portion and the non-trench portion of the resist underlayer film than the comparative resist underlayer film-forming compositions (Comparative Examples UDL-1 to 8), and are therefore superior in planarization properties. Focusing on the structure of the crosslinking agent, compositions for forming resist underlayer films (Examples UDL-3 to UDL-5) containing crosslinking agents (B3 to B5) having a non-aromatic unsaturated carbon bond showed excellent planarization properties. In contrast, the resist underlayer-forming compositions (Comparative Examples UDL-2 to UDL-5) containing comparative polymeric compounds (R1) to (R4) as component (A) exhibited poor planarization properties. This is presumably because (R2) to (R4) contain aromatic rings in their repeating unit structures, which reduces fluidity. Furthermore, in the comparative examples UDL-1, which does not contain a crosslinking agent corresponding to component (B), and the comparative examples UDL-6, UDL-7, and UDL-8, which are compositions for forming resist underlayer films that use, as component (B), crosslinking agents (X1), (B8), and (B9) outside the scope of formula (B-1) of the present invention, the planarization properties were insufficient. It is presumed that the high curing properties of the crosslinking agents reduce the thermal fluidity during baking, resulting in poor planarization.

[0226] [Evaluation of alkaline hydrogen peroxide solution resistance (Examples 5-1 to 5-14, Comparative Examples 5-1 to 5-4)] The resist underlayer film material was deposited on a silicon wafer cut into 3 cm squares, baking at 250°C to a thickness of approximately 100 nm. The wafer pieces were immersed in a 1.0% by weight hydrogen peroxide solution containing 0.5% by weight ammonia at 70°C for 5 minutes, then rinsed with deionized water. The resist underlayer film was visually inspected for peeling from the wafer. If the resist underlayer film peeled partially or completely, exposing the silicon wafer surface, the resist underlayer film tested was deemed to have insufficient alkaline hydrogen peroxide resistance. The results are shown in Table 7.

[0227] [Table 7]

[0228] The above results demonstrate that the resist underlayer film materials of the examples (UDL-1 to 14) are superior in alkaline hydrogen peroxide resistance to the resist underlayer film materials of the comparative examples (Comparative UDL-1 to 4).

[0229] From the above, it has become clear that the resist underlayer film-forming composition, pattern formation method, and resist underlayer film-forming method of the present invention can be suitably used in a multilayer resist process for fine patterning in the manufacture of semiconductor devices, and in particular, since they have good alkaline hydrogen peroxide resistance, excellent filling / planarization properties, and excellent dry etching properties in addition to antireflection function, they can also be applied to multilayer resist processes including wet etching processing and ion implantation processes, and are extremely useful industrially.

[0230] This specification includes the following inventions. [1]: A composition for forming a resist underlayer film, (A) A polymer compound having a structural unit (a1) represented by the following formula (A-1) and at least one structural unit (a2) selected from the structural units represented by the following formulas (A-2) to (A-4): (B) a crosslinking agent represented by the following formula (B-1): (C) organic solvent, A composition for forming a resist underlayer film, comprising: [ka] (In the formula, R 01 is a hydrogen atom or a methyl group, and R 02 is a monovalent organic group containing a group selected from groups represented by the following formulas (R2-1) to (R2-3): [ka] (In the formula, R a represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the dashed line represents a bond. [ka] (In formula (A-2), X represents an aromatic ring having 6 to 20 carbon atoms or a single bond, and R 03 is a hydrogen atom or a methyl group, and R 04 is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and R 04 When R is an alkyl group, a hydrogen atom constituting the alkyl group may be substituted with a hydroxyl group. 05 is a hydrogen atom or a methyl group, and R 06 is a divalent linking group having 2 to 10 carbon atoms and containing a single bond or an ester group, and R 07 is a tertiary alkyl group having 4 to 20 carbon atoms or a tertiary alkenyl group having 5 to 20 carbon atoms. 05 , R 06 has the same meaning as in formula (A-3), and R 08 is a hydrogen atom or a monovalent primary alkyl group having 1 to 10 carbon atoms. [ka] (In the formula, R 5 represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following (B-2), and R 1 , R 3 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 2 , R 4 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group. [ka] (In the formula, R 7 represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. 6 represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group, and R 2 , R 4 When is a hydrogen atom, R 6 is also a hydrogen atom.) [2]: R in the formula (B-1) 1 , R 3 , R 7The composition for forming a resist underlayer film according to [1], wherein two or more of the groups are naphthoyl groups or anthranoyl groups. [3]: R in the formula (B-1) 2 , R 4 , R 5 The composition for forming a resist underlayer film according to [1] or [2], wherein either one of the above has a non-aromatic unsaturated bond. [4]: The composition for forming a resist underlayer film according to any one of [1] to [3], wherein the content of the (B) crosslinking agent contained in the composition for forming a resist underlayer film is in the range of 1 to 50 parts by mass per 100 parts by mass of the (A) polymer compound. [5]: The composition for forming a resist underlayer film according to any one of [1] to [4], wherein the polymer compound (A) has a structural unit (a1) represented by the formula (A-1) and at least two structural units (a2) selected from the structural units represented by the formulas (A-2) to (A-4). [6]: The composition for forming a resist underlayer film according to any one of [1] to [5], wherein in the polymer compound (A), the content of the structural unit (a1) is 20 mol % or more and 90 mol % or less, and the total content of the structural unit (a2) is 10 mol % or more and 80 mol % or less, based on all repeating units. [7]: The composition for forming a resist underlayer film according to any one of [1] to [6], wherein the weight-average molecular weight of the polymer compound (A) is 1,000 to 20,000. [8]: The composition for forming a resist underlayer film according to any one of [1] to [7], wherein the dispersity of the polymer compound (A), expressed as weight average molecular weight / number average molecular weight, is 3.0 or less. [9]: The composition for forming a resist underlayer film according to any one of [1] to [8], which comprises at least one selected from (D) an acid generator and (E) a surfactant.

[10] : The composition for forming a resist underlayer film according to any one of [1] to [9], wherein the composition for forming a resist underlayer film provides a resist underlayer film that exhibits resistance to an ammonia-containing hydrogen peroxide solution.

[11] : A method for forming a pattern on a workpiece substrate, (I-1) a step of applying the composition for forming a resist underlayer film according to any one of [1] to

[10] onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a composition for forming a resist upper layer film; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the resist underlayer film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; A pattern forming method comprising the steps of:

[12] : A method for forming a pattern on a workpiece substrate, (II-1) A step of applying the composition for forming a resist underlayer film according to any one of [1] to

[10] onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (II-2) forming a silicon atom-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon atom-containing resist intermediate film using a composition for forming a resist upper layer film; (II-4) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (II-5) a step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the silicon atom-containing resist intermediate film to which the pattern has been transferred as a mask; A pattern forming method comprising the steps of:

[13] : A method for forming a pattern on a workpiece substrate, (III-1) A step of applying the composition for forming a resist underlayer film according to any one of [1] to

[10] onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (III-2) forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film; (III-3) forming an organic anti-reflective coating on the inorganic hard mask; (III-4) forming a resist upper layer film on the organic antireflective film using a composition for forming a resist upper layer film; (III-5) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (III-6) a step of transferring a pattern to the organic anti-reflective film and the inorganic hard mask by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (III-7) a step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask to which the pattern has been transferred as a mask; A pattern forming method comprising the steps of:

[14] : The pattern forming method according to any one of

[11] to

[13] , further comprising, after the step (I-4), the step (II-6), or the step (III-7), a step of transferring a pattern to the workpiece substrate by wet etching using an alkaline hydrogen peroxide solution, using the resist underlayer film to which the pattern has been transferred as a mask.

[15] : The pattern formation method according to any one of

[11] to

[13] , characterized in that after the step (I-4), the step (II-6), or the step (III-7), a step of patterning the substrate to be processed by ion implantation using the resist underlayer film to which the pattern has been transferred as a mask is further included.

[16] : The pattern forming method according to any one of

[11] to

[13] , wherein the composition for forming the resist underlayer film has a dry etching rate higher than the dry etching rate of the resist upper layer film.

[17] The pattern formation method according to any one of

[11] to

[13] , wherein a substrate having a structure or step having a height of 30 nm or more is used as the substrate to be processed.

[18] : A method for forming a resist underlayer film used in a manufacturing process of a semiconductor device, comprising spin-coating a substrate to be processed with the composition for forming a resist underlayer film according to any one of [1] to

[10] , and heat-treating the substrate coated with the composition for forming a resist underlayer film at a temperature of 100°C or higher and 300°C or lower for 10 to 600 seconds to form a resist underlayer film.

[0231] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0232] 1...substrate, 2...processed layer, 2a...pattern formed on substrate, 3...resist underlayer film, 3a...resist underlayer film pattern, 4...resist intermediate film, 4a...resist intermediate film pattern, 5...resist upper layer film, 5a...resist pattern, 6...desired portion, 7...Base substrate having a dense hole pattern, 8...Resist underlayer film, 9...Base substrate having a huge isolated trench pattern, 10...Resist underlayer film, Delta 10: Difference in thickness between the resist underlayer film in the trench area and the non-trench area.

Claims

1. A composition for forming a resist underlayer film, (A) a polymeric compound having a structural unit (a1) represented by the following formula (A-1) and at least one structural unit (a2) selected from structural units represented by the following formulas (A-2) to (A-4): (B) a crosslinking agent represented by the following formula (B-1): (C) an organic solvent, A composition for forming a resist underlayer film, comprising: 【Chemistry 1】 (In the formula, R ０１ is a hydrogen atom or a methyl group, and R ０２ is expressed by the following formula (R ２ -1) to (R ２ -3) is a monovalent organic group containing a group selected from the groups represented by 【Chemistry 2】 (In the formula, R ａ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the dashed line represents a bond. 【Transformation 3】 (In formula (A-2), X is an aromatic ring having 6 to 20 carbon atoms or a single bond, and R ０３ is a hydrogen atom or a methyl group, and R ０４ is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms, and R ０４ When R is an alkyl group, a hydrogen atom constituting the alkyl group may be substituted with a hydroxyl group. ０５ is a hydrogen atom or a methyl group, and R ０６ is a divalent linking group having 2 to 10 carbon atoms and containing a single bond or an ester group, and R ０７ is a tertiary alkyl group having 4 to 20 carbon atoms or a tertiary alkenyl group having 5 to 20 carbon atoms. ０５ , R ０６ has the same meaning as in formula (A-3), and R ０８ is a hydrogen atom or a monovalent primary alkyl group having 1 to 10 carbon atoms. 【Chemistry 4】 (In the formula, R ５ represents a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following (B-2), and R １ , R ３ represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. ２ , R ４ represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group. 【Transformation 5】 (In the formula, R ７ represents a benzoyl group, a toluoyl group, a naphthoyl group, or an anthranoyl group. ６ represents a hydrogen atom, an acetyl group, an acryloyl group, or a methacryloyl group; R ２ , R ４ When is a hydrogen atom, R ６ is also a hydrogen atom.)

2. In the formula (B-1), R １ , R ３ , R ７ 2. The composition for forming a resist underlayer film according to claim 1, wherein two or more of the following are naphthoyl groups or anthranoyl groups.

3. In the formula (B-1), R ２ , R ４ , R ５ 2. The composition for forming a resist underlayer film according to claim 1, wherein any one of the following has an unsaturated bond other than an aromatic bond.

4. 2. The composition for forming a resist underlayer film according to claim 1, wherein the content of the (B) crosslinking agent contained in the composition for forming a resist underlayer film is in the range of 1 to 50 parts by mass relative to 100 parts by mass of the (A) polymer compound.

5. The composition for forming a resist underlayer film according to claim 1, wherein the polymer compound (A) has a structural unit (a1) represented by formula (A-1) and at least two structural units (a2) selected from the structural units represented by formulas (A-2) to (A-4).

6. 2. The composition for forming a resist underlayer film according to claim 1, wherein, in the polymer compound (A), a content of the structural unit (a1) is 20 mol % or more and 90 mol % or less, and a total content of the structural unit (a2) is 10 mol % or more and 80 mol % or less, based on all repeating units.

7. 2. The composition for forming a resist underlayer film according to claim 1, wherein the polymer compound (A) has a weight average molecular weight of 1,000 to 20,000.

8. 2. The composition for forming a resist underlayer film according to claim 1, wherein the polymer compound (A) has a dispersity expressed as weight average molecular weight / number average molecular weight of 3.0 or less.

9. 2. The composition for forming a resist underlayer film according to claim 1, further comprising at least one selected from the group consisting of (D) an acid generator and (E) a surfactant.

10. 2. The composition for forming a resist underlayer film according to claim 1, which provides a resist underlayer film that exhibits resistance to an ammonia-containing hydrogen peroxide solution.

11. A method for forming a pattern on a workpiece substrate, comprising: (I-1) a step of applying the composition for forming a resist underlayer film according to claim 1 onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a composition for forming a resist upper layer film; (I-3) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (I-4) a step of transferring the pattern to the resist underlayer film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; A pattern forming method comprising the steps of:

12. A method for forming a pattern on a workpiece substrate, comprising: (II-1) a step of applying the composition for forming a resist underlayer film according to claim 1 onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (II-2) forming a silicon atom-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon atom-containing resist intermediate film using a composition for forming a resist upper layer film; (II-4) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (II-5) a step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the silicon atom-containing resist intermediate film to which the pattern has been transferred as a mask; A pattern forming method comprising the steps of:

13. A method for forming a pattern on a workpiece substrate, comprising: (III-1) A step of applying the composition for forming a resist underlayer film according to claim 1 onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (III-2) forming an inorganic hard mask selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film; (III-3) forming an organic anti-reflective coating on the inorganic hard mask; (III-4) forming a resist upper layer film on the organic antireflective film using a composition for forming a resist upper layer film; (III-5) a step of pattern-exposing the resist upper layer film and then developing it with a developer to form a circuit pattern on the resist upper layer film; (III-6) a step of transferring a pattern to the organic anti-reflective film and the inorganic hard mask by dry etching using the resist upper layer film on which the circuit pattern has been formed as a mask; (III-7) transferring the pattern to the resist underlayer film by dry etching using the inorganic hard mask to which the pattern has been transferred as a mask; A pattern forming method comprising the steps of:

14. 14. The pattern forming method according to claim 11, further comprising, after the step (I-4), the step (II-6), or the step (III-7), a step of transferring a pattern to the workpiece substrate by wet etching using an alkaline hydrogen peroxide solution, using the resist underlayer film to which the pattern has been transferred as a mask.

15. 14. The pattern formation method according to claim 11, further comprising, after the step (I-4), the step (II-6), or the step (III-7), a step of patterning the workpiece substrate by performing ion implantation using the resist underlayer film to which the pattern has been transferred as a mask.

16. 14. The pattern formation method according to claim 11, wherein the composition for forming the resist underlayer film has a dry etching rate higher than a dry etching rate of the resist upper layer film.

17. 14. The pattern formation method according to claim 11, wherein the substrate to be processed has a structure or step having a height of 30 nm or more.

18. A method for forming a resist underlayer film used in a manufacturing process of a semiconductor device, comprising spin-coating the composition for forming a resist underlayer film according to any one of claims 1 to 10 onto a substrate to be processed, and heat-treating the substrate coated with the composition for forming a resist underlayer film at a temperature of 100°C or higher and 300°C or lower for 10 to 600 seconds, thereby forming a resist underlayer film.

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