Resist underlayer film material, pattern forming method, and resist underlayer film forming method

Abstract

To provide a resist underlayer film material which enables formation of a resist underlayer film excellent in flatness and film-forming property even on a processed substrate having a wide trench structure, especially, a part that is difficult to be flattened, in a fine patterning process by a multilayer resist method in a semiconductor device manufacturing process, and gives a resist underlayer film having appropriate etching characteristics, and a pattern forming method using the material and a resist underlayer film forming method.SOLUTION: A resist underlayer film material contains (A) a compound containing a phenolic hydroxyl group or a resin, (B) a base generator, and (C) an organic solvent.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resist underlayer film material that can be used for fine patterning by a multilayer resist method in a semiconductor device manufacturing process, a pattern forming method using the material, and a resist underlayer film forming method.

Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern dimensions has been rapidly progressing. Along with this miniaturization, lithography technology has achieved the formation of fine patterns by shortening the wavelength of the light source and appropriately selecting a resist composition for it. At the center of this is a positive photoresist composition used in a single layer. This single-layer positive photoresist composition has a skeleton in the resist resin that has etching resistance against dry etching with chlorine-based or fluorine-based gas plasmas, and has a switching mechanism such that the exposed portion dissolves. By dissolving the exposed portion to form a pattern and using the remaining resist pattern as an etching mask to dry-etch the substrate to be processed.

[0003] However, when the film thickness of the photoresist film used is directly miniaturized, that is, when the pattern width is made smaller, the resolution performance of the photoresist film decreases. Also, when trying to develop the photoresist film into a pattern with a developer, the so-called aspect ratio becomes too large, and as a result, a problem occurs in that pattern collapse occurs. For this reason, the photoresist film has been thinned as the pattern is miniaturized.

[0004] On one hand, for processing a substrate to be processed, usually, a method of processing the substrate by dry etching using a photoresist film with a pattern formed thereon as an etching mask is employed. However, in reality, there is no dry etching method that can achieve perfect etching selectivity between the photoresist film and the substrate to be processed. Therefore, during the processing of the substrate, the resist film is also damaged and collapses, resulting in the problem that the resist pattern cannot be accurately transferred to the substrate to be processed. Thus, with the miniaturization of patterns, higher dry etching resistance has been required for resist compositions. However, on the other hand, in order to improve the resolution, resins used in photoresist compositions have been required to have low light absorption at the exposure wavelength. Therefore, as the exposure light has become shorter in wavelength, such as i-line, KrF, and ArF, the resins have also changed from novolak resins, polyhydroxystyrene, to resins having an aliphatic polycyclic skeleton. However, in reality, the etching rate under the dry etching conditions during substrate processing has become faster, and recent photoresist compositions with high resolution tend to have weaker etching resistance.

[0005] From this, it becomes necessary to dry-etch the substrate to be processed with a thinner and less etching-resistant photoresist film, and it is important to ensure the materials and processes in this processing step.

[0006] As one method to solve such problems, there is a multilayer resist method. This method involves interposing an intermediate film with different etching selectivity between the photoresist film (i.e., the resist upper layer film) and the substrate to be processed. After obtaining a pattern on the resist upper layer film, the resist upper layer film pattern is used as a dry etching mask to transfer the pattern to the intermediate film by dry etching, and further, the intermediate film is used as a dry etching mask to transfer the pattern to the substrate to be processed by dry etching.

[0007] One of the multilayer resist methods is a three-layer resist method that can be performed using a general resist composition used in the single-layer resist method. In this three-layer resist method, for example, an organic film made of novolak resin or the like is formed as a resist underlayer film on a substrate to be processed, a silicon-containing film is formed as a resist intermediate film thereon, and a normal organic photoresist film is formed as a resist upper layer film thereon. When performing dry etching with a fluorine-based gas plasma, the organic resist upper layer film has a good etching selectivity with respect to the silicon-containing resist intermediate film, so the resist upper layer film pattern can be transferred to the silicon-containing resist intermediate film by dry etching with a fluorine-based gas plasma. According to this method, even when using a resist composition that is difficult to form a pattern with a sufficient film thickness for directly processing the substrate to be processed or a resist composition that does not have sufficient dry etching resistance for substrate processing, a pattern can be transferred to the silicon-containing film (resist intermediate film), and then, by performing pattern transfer by dry etching with an oxygen-based or hydrogen-based gas plasma, a pattern of an organic film (resist underlayer film) made of novolak resin or the like that has sufficient dry etching resistance for substrate processing can be obtained. As the resist underlayer film as described above, many are already known, such as those described in Patent Document 1, for example.

[0008] In recent years, the manufacturing study of semiconductor devices having new structures such as multi-gate structures has been actively carried out. In response to this, the requirements for better planarization characteristics and embedding characteristics than before have been increasing for the resist underlayer film. For example, when there are minute pattern structures such as holes, trenches, and fins on the underlying substrate to be processed, the resist underlayer film needs to have the property of filling the inside of the pattern with a film without voids (gap-filling). Also, when there are steps on the underlying substrate to be processed, or when a pattern-dense portion and a patternless region exist on the same wafer, it is necessary to planarize the film surface with the resist underlayer film. By planarizing the surface of the underlayer film, the film thickness variation of the resist intermediate film and the resist upper layer film formed thereon can be suppressed, and the focus margin of lithography and the margin reduction in the subsequent processing steps of the substrate to be processed can be suppressed.

[0009] Moreover, the organic film material excellent in embedding / planarization characteristics is not limited to the underlayer film for multilayer resist, and can be widely applied as a planarization material for semiconductor device manufacturing, such as substrate planarization prior to patterning by nanoimprinting. Further, the CMP process is currently generally used for global planarization in the semiconductor device manufacturing process, but CMP is a high-cost process, and it is also expected as a material responsible for an alternative global planarization method.

[0010] For forming a planarization film to planarize a semiconductor substrate with irregularities, a resist underlayer film material containing a compound with low viscosity and high heat fluidity has been proposed (Patent Document 2). However, this material has problems such as significantly reduced wettability to a hydrophobic substrate treated with, for example, hexamethyldisilazane (hereinafter referred to as HMDS), and an increased tendency to generate pinholes and film edge recession. Furthermore, in state-of-the-art devices, as the upper resist film becomes thinner due to pattern miniaturization, the lower resist film also becomes thinner, making it more difficult to ensure wettability. To improve the wettability of the underlayer film material, it is effective to improve the adhesion to the substrate, and a resist underlayer film material having an amide structure as a constituent component of a polar functional group has been proposed (Patent Document 3). However, although this resist underlayer film material has both wettability and flatness on a silicon substrate, its wettability to a hydrophobic substrate is insufficient. Thus, there is a need for an underlayer film material that combines excellent planarization characteristics, wettability to a hydrophobic substrate, and sufficient etching resistance, and a patterning method using the same.

[0011] Also, as described above, the structure of the substrate to be processed has become more complex, and furthermore, new materials with high electron mobility such as strained silicon and gallium arsenide, and ultrathin polysilicon controlled in angstrom units are also being considered for the surface of the substrate to be processed, and it is assumed that film formation will be performed on various substrate surface shapes and materials. Therefore, in order to ensure a process margin, not only excellent planarization characteristics but also the ability to form a film without depending on the material and shape of the substrate to be processed are important characteristics.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0013] The present invention has been made in view of the above circumstances, and in a fine patterning process by a multilayer resist method in a semiconductor device manufacturing process, even on a substrate to be processed having a particularly difficult-to-flatten portion such as a wide trench structure, a resist underlayer film excellent in flatness and film-forming property can be formed, and further, a resist underlayer film material that provides a resist underlayer film having appropriate etching characteristics, and a pattern forming method and a resist underlayer film forming method using the material are provided.

Means for Solving the Problems

[0014] In order to solve the above problems, in the present invention, (A) a compound or resin containing a phenolic hydroxyl group, (B) a base generator, and (C) an organic solvent A resist underlayer film material characterized by containing the above is provided.

[0015] With such a resist underlayer film material, in a fine patterning process by a multilayer resist method, even on a substrate to be processed having a difficult-to-flatten portion, a resist underlayer film excellent in flatness and film-forming property can be formed, and this underlayer film further has appropriate etching characteristics. For example, a resist underlayer film excellent in film-forming property on a hydrophobic substrate treated with HMDS can be formed.

[0016] Further, it is preferable that the polystyrene-reduced weight average molecular weight of the component (A) is 3,000 or less.

[0017] With such a resist underlayer film material, since it has low viscosity and high heat fluidity, a resist underlayer film excellent in flatness and compatible with film-forming property on a hydrophobic substrate can be formed.

[0018] Furthermore, it is preferable that the (B) base generator is a compound that exhibits basicity by thermal decomposition.

[0019] For such a resist underlayer film material, it is assumed that the film-forming property is excellent because the phenolic hydroxyl group has ionic properties during film baking and the interaction with the substrate increases. By adjusting the addition amount, it is possible to achieve both thermal fluidity and interaction with the substrate.

[0020] Furthermore, it is preferable that the (B) base generator is any one of the following general formulas (1), (2), and (3). [Chemical formula] (In the above formula, R 01 ~R 03 each independently represents a linear, branched, or cyclic alkyl group or alkenyl group having 1 to 10 carbon atoms which may be substituted with a heteroatom or may have a heteroatom intervening, or represents an aryl group or aralkyl group having 6 to 18 carbon atoms which may be substituted with a heteroatom or may have a heteroatom intervening. Also, any two of R 01 , R 02 and R 03 may be bonded to each other to form a ring together with the sulfur atom in the formula. X - represents an organic or inorganic anion that serves as a counterion. However, X - does not include OH - . R 04 and R 05 each independently represents an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms thereof may be substituted with a linear, branched, or cyclic alkyl group or alkoxy group having 1 to 10 carbon atoms. Also, R 04 and R 05 may be bonded to each other to form a ring together with the iodine atom in the formula. R 06 , R 07 , R 08 and R 09 each independently represents a hydrogen atom, or a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms which may be substituted with a heteroatom or may have a heteroatom intervening.Or Alkenyl group represents an aryl group or an aralkyl group having 6 to 18 carbon atoms which may be substituted with a heteroatom or may have a heteroatom intervening therebetween. Further, R 06 , R 07 , R 08 and R 09 may be bonded to each other to form a ring together with the nitrogen atom in the formula.)

[0021] Furthermore, X - in the general formulas (1), (2) and (3) is more preferably a structure represented by any of the following general formulas (4), (5) and (6), and an anion selected from the group consisting of chloride ion, bromide ion, iodide ion, fluoride ion, cyanide ion, nitrate ion, and nitrite ion. [Chemical formula] (In the above formula, R 10 represents a linear, branched or cyclic alkyl group, alkenyl group, aralkyl group or aryl group having 1 to 20 carbon atoms which may contain an ether group, an ester group or a carbonyl group, and one or more hydrogen atoms of these groups may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. R 11 represents an aryl group having 1 to 20 carbon atoms. One or more hydrogen atoms of the aryl group may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. R 12 , R 13 , R 14 each independently represents a hydrogen atom, a halogen atom other than fluorine, or a linear, branched or cyclic alkyl group, alkenyl group, aralkyl group or aryl group having 1 to 20 carbon atoms which may contain an ether group, an ester group or a carbonyl group, and one or more hydrogen atoms of these groups may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. Further, two or more of R 12 , R 13 , R 14 may be bonded to each other to form a ring.)

[0022] Furthermore, it is more preferable that the boiling point of the conjugate acid X-H of X in the general formulas (1), (2) and (3) is 200 °C or lower. - By appropriately selecting a base generator (thermal base generator) that exhibits basicity through such thermal decomposition, it is possible to exhibit basicity in accordance with the firing temperature of the resist underlayer film material, and it is possible to achieve both film formability and flatness. In addition, since the entire amount decomposes or evaporates during firing and does not remain in the film after firing, it does not adversely affect the performance other than film formability. In this specification, the boiling point is the value at 1 atmosphere (1013 hPa).

[0023] Moreover, it is preferable that the compound containing a phenolic hydroxyl group in (A) is represented by the following general formula (7).

[0024]

Chemical formula

Chemical formula

Chemical formula

[0025] ​With such a resist underlayer film material, even on a substrate to be processed having a particularly difficult-to-flatten portion such as a wide trench structure, a resist underlayer film excellent in flatness and film-forming property can be formed. Further, if the resist underlayer film material satisfies the above relationship between a and b, it becomes possible to form a resist underlayer film having both flatness and film-forming property.

[0026] Furthermore, it is preferable that A in the general formula (8) is -OCH2-.

[0027] With such a resist underlayer film material, shrinkage of the film due to thermosetting can be suppressed, and a resist underlayer film excellent in flatness can be formed.

[0028] Furthermore, it is preferable that the general formula (8) is any one of the following general formulas (10), (11), and (12).

Chemical formula

[0029] With such a resist underlayer film material, not only the flatness improvement effect due to shrinkage suppression but also various properties such as heat resistance and etching resistance can be imparted, and a resist underlayer film excellent in process margin can be formed.

[0030] Furthermore, it is preferable that the general formula (9) is any one of the following general formulas (13) or (14).

Chemical formula

[0031] By introducing such a terminal group structure into the resist underlayer film material, adhesion to the substrate is imparted, and by combining with a thermal base generator, a greater film-forming property improvement effect can be obtained. In particular, it is effective in suppressing the recession of the film edge.

[0032] Further, it is preferable that W in the general formula (7) is represented by the following general formula (15).

Chemical formula

[0033] Furthermore, it is more preferable that W in the general formula (15) has a structure represented by any of the following formulas. 1

Chemical formula

Chemical formula

[0034]

Chemical formula

[0035] With such a resist underlayer film material, a resist underlayer film excellent in film formability and flatness can be formed, and it can be manufactured particularly easily.

[0036] Further, it is preferable that the organic solvent (C) is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher.

[0037] With such a resist underlayer film material, the flatness of the formed resist underlayer film can be further improved regardless of the design of the substrate to be processed such as pattern density.

[0038] Furthermore, the resist underlayer film material of the present invention can contain one or more of (D) a surfactant, (E) a crosslinking agent, (F) a plasticizer, and (G) a pigment.

[0039] Thus, in the resist underlayer film material of the present invention, (D) a surfactant can be added to improve coatability in spin coating, (E) a crosslinking agent can be added to further promote the crosslinking and curing reaction, (F) a plasticizer can be added to further improve the embedding / planarization characteristics, and (G) a dye can be added to adjust the light absorption characteristics. By the presence / selection of these various additives, fine adjustment of performance according to requirements such as film-forming property, curability, embeddability, and optical properties becomes possible, which is practically preferable.

[0040] Further, it is preferable that the (E) crosslinking agent is a compound represented by the following general formula (16). [Chemical formula] (In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 16 is hydrogen or an alkyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5.)

[0041] With such a crosslinking agent, the crosslinking reaction proceeds even without containing an acid generator, so that the curability can be improved without impairing the effect of improving the film-forming property of the base generator. Further, since the crosslinking agent of the general formula (16) itself also contains a phenolic hydroxyl group, a higher effect of improving the film-forming property is expected by the action of the base generator.

[0042] The present invention also relates to a method for forming a pattern on a substrate to be processed, comprising: (I-1) a step of forming a resist underlayer film by applying the above resist underlayer film material on the substrate to be processed and then performing heat treatment; (I-2) a step of forming a resist upper layer film on the resist underlayer film using a photoresist material; (I-3) a step of forming a pattern on the resist upper layer film by pattern exposure and then developing with a developer; (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 pattern is formed as a mask, and (I-5) A step of processing the substrate to be processed using the resist underlayer film on which the above pattern is formed as a mask to form a pattern on the substrate to be processed. Provided is a pattern forming method characterized by having the above.

[0043] Further, the present invention is a method for forming a pattern on a substrate to be processed, comprising: (II-1) A step of forming a resist underlayer film by applying the above resist underlayer film material on the substrate to be processed and then performing heat treatment. (II-2) A step of forming a resist intermediate film on the resist underlayer film. (II-3) A step of forming a resist upper layer film using a photoresist material on the resist intermediate film. (II-4) A step of performing pattern exposure on the resist upper layer film and then developing with a developer to form a pattern on the resist upper layer film. (II-5) A step of transferring the pattern to the resist intermediate film by dry etching using the resist upper layer film on which the pattern is formed as a mask. (II-6) A step of transferring the pattern to the resist underlayer film by dry etching using the resist intermediate film on which the pattern is transferred as a mask, and (II-7) A step of processing the substrate to be processed using the resist underlayer film on which the above pattern is formed as a mask to form a pattern on the substrate to be processed. Provided is a pattern forming method characterized by having the above.

[0044] Further, the present invention is a method for forming a pattern on a substrate to be processed, comprising: (III-1) A step of forming a resist underlayer film by applying the above resist underlayer film material on the substrate to be processed and then performing heat treatment. (III-2) A step of forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film. (III-3) A step of forming an organic thin film on the inorganic hard mask intermediate film. (III-4) A step of forming an upper resist film on the organic thin film using a photoresist material. (III-5) After pattern exposure of the upper resist film, developing with a developer to form a pattern in the upper resist film. (III-6) Using the upper resist film with the pattern formed as a mask, transferring the pattern to the organic thin film and the inorganic hard mask intermediate film by dry etching. (III-7) Using the inorganic hard mask intermediate film with the pattern transferred as a mask, transferring the pattern to the lower resist film by dry etching, and (III-8) Using the lower resist film with the pattern formed as a mask to process the substrate to be processed and form a pattern on the substrate to be processed. provided is a pattern formation method characterized by having the above steps.

[0045] Thus, the lower resist film material of the present invention can be suitably used in various pattern formation methods such as a two-layer resist process, a three-layer resist process using a resist intermediate film, and a four-layer resist process using an organic thin film in addition to these. With these pattern formation methods, the unevenness and steps of the substrate to be processed can be effectively alleviated by forming the lower resist film, and it is suitable for photolithography of the upper resist film.

[0046] Further, in the pattern formation method of the present invention, the inorganic hard mask intermediate film can be formed by a CVD method or an ALD method.

[0047] In the pattern formation method of the present invention, a combination of an inorganic hard mask intermediate film formed by a CVD method or an ALD method and a lower resist film formed by a spin coating method is possible.

[0048] Further, in the pattern formation method of the present invention, as the substrate to be processed, it is possible to use a substrate having a structure or step with a height of 30 nm or more.

[0049] Furthermore, in the pattern formation method of the present invention, it is possible to use a substrate having a static contact angle with respect to water of 50° or more as the substrate to be processed.

[0050] Since the resist underlayer film material of the present invention is excellent in embedding / planarizing characteristics and film-forming properties on a hydrophobic substrate, it is particularly useful for microfabrication of a substrate having such a structure or step.

[0051] The present invention also provides a method for forming a resist underlayer film that functions as an organic planarizing film used in the manufacturing process of a semiconductor device. The method includes spin-coating the above-described resist underlayer film material on a substrate to be processed, and heat-treating the substrate coated with the resist underlayer film material at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds to cure and form a resist underlayer film.

[0052] The present invention also provides a method for forming a resist underlayer film that functions as an organic planarizing film used in the manufacturing process of a semiconductor device. The method includes spin-coating the above-described resist underlayer film material on a substrate to be processed, and heat-treating the substrate coated with the resist underlayer film material in an atmosphere having an oxygen concentration of 1% by volume or more and 21% by volume or less to cure and form a resist underlayer film.

[0053] By such a method, the crosslinking reaction during the formation of the resist underlayer film can be promoted, and mixing with the upper layer film can be more highly suppressed. Further, by appropriately adjusting the heat treatment temperature, time, and oxygen concentration within the above ranges, the embedding / planarizing characteristics and curing characteristics of a resist underlayer film suitable for the application can be obtained.

[0054] The present invention also provides a method for forming a resist underlayer film that functions as an organic planarizing film used in the manufacturing process of a semiconductor device. The method includes spin-coating the above-described resist underlayer film material on a substrate to be processed, and heat-treating the substrate coated with the resist underlayer film material in an atmosphere having an oxygen concentration of less than 1% by volume to cure and form a resist underlayer film.

[0055] By such a method, even when the substrate to be processed contains a material that is unstable to heating in an oxygen atmosphere, it is useful because it can promote the crosslinking reaction during the formation of the resist underlayer film without causing deterioration of the substrate to be processed, and can more highly suppress mixing with the upper layer film.

[0056] Further, as the substrate to be processed, a substrate having a structure or step with a height of 30 nm or more can be used.

[0057] Furthermore, as the substrate to be processed, a substrate having a static contact angle with respect to water of 50° or more can be used.

[0058] The method for forming a resist underlayer film of the present invention uses the resist underlayer film material of the present invention capable of forming a resist underlayer film excellent in embedding / planarization characteristics and film formability on a hydrophobic substrate, and is particularly suitable for forming a resist underlayer film on a substrate having such a structure or step.

Advantages of the Invention

[0059] As described above, the resist underlayer film material, pattern forming method, and resist underlayer film forming method of the present invention are particularly preferably used in a multilayer resist process including planarization of a substrate to be processed having steps and unevenness, and are extremely useful in fine patterning for manufacturing semiconductor devices. In particular, in a fine patterning process by a multilayer resist method in a semiconductor device manufacturing process, even on a substrate to be processed having a particularly difficult-to-planarize portion such as a wide trench structure without containing an acid generator, it is possible to form a resist underlayer film excellent in flatness and capable of film formation without substrate dependence, and further provide a resist underlayer film material having appropriate etching characteristics and optical characteristics, a pattern forming method using the material, and a resist underlayer film forming method. In particular, since the base generated by baking or the like acts on the phenolic hydroxyl group to increase its ionic property and strengthen the interaction with the substrate surface, even when forming a resist underlayer film on a hydrophobized wafer such as by HMDS treatment, the occurrence of pinholes and edge shrinkage (receding) can be suppressed.

Brief Description of the Drawings

[0060]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0061] As described above, in the fine patterning process by the multilayer resist method in the semiconductor device manufacturing process, even on a substrate to be processed having a particularly difficult - to - planarize portion such as a wide trench structure, it is possible to form a resist underlayer film excellent in film - forming property and flatness. Furthermore, a resist underlayer film material having excellent embedding properties, appropriate etching properties and optical properties, a pattern formation method using the said material, and a resist underlayer film formation method have been demanded.

[0062] The present inventor has searched for various resist underlayer film materials and pattern formation methods in order to realize high - level embedding / planarization and excellent film - forming property by forming an underlayer film in multilayer lithography using a resist underlayer film. As a result, it has been found that a resist underlayer film material mainly composed of a compound or resin containing a phenolic hydroxyl group and a base generator, a pattern formation method using the said material, and a resist underlayer film formation method are very effective, and the present invention has been completed.

[0063] That is, the present invention is (A) A compound or resin containing a phenolic hydroxyl group, (B) A base generator, and, (C) An organic solvent characterized by comprising a resist underlayer film material.

[0064] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0065] <Resist underlayer film material> The resist underlayer film material of the present invention is a resist underlayer film material that can be used in the multilayer resist method as described above, and (A) A compound or resin containing a phenolic hydroxyl group, (B) A base generator, and (C) An organic solvent is included.

[0066] [(A) Compound or resin containing a phenolic hydroxyl group] Since the resist underlayer film material of the present invention contains a compound or resin containing a phenolic hydroxyl group, it has excellent substrate affinity, so it is considered that a resist underlayer film having excellent film-forming properties can be formed even on a substrate to be processed having a complex fine structure and various surface materials. In particular, it has excellent film-forming properties in forming a film on a hydrophobic substrate treated with HMDS.

[0067] The formula weight of the compound (A) containing a phenolic hydroxyl group is preferably 300 to 3,000, and particularly preferably 500 to 2,500. If the molecular weight is 300 or more, the film-forming property is excellent, and there is no problem of contaminating the apparatus due to an increase in the sublimation product during curing. If the molecular weight is 3,000 or less, the complex viscosity of the resin decreases during firing, showing high thermal fluidity and excellent planarization / embedding characteristics. In the present invention, the molecular weight can be the weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent. The number average molecular weight (Mn) and the dispersity (Mw / Mn) can also be determined in this way. The dispersity of the component (A) can be 1.0 to 2.5, but the dispersity of the compound containing a phenolic hydroxyl group is preferably 1.0 to 1.5.

[0068] Examples of the compound containing the phenolic hydroxyl group (A) include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, hydroquinone, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-butyl-5-methylphenol, pyrogallol, thymol, isothymol, 4,4'-(9H-fluorene-9-ylidene)bisphenol, 2,2'dimethyl-4,4'-(9H-fluorene-9-ylidene)bisphenol, 2,2'diallyl-4,4'-(9H-fluorene-9-ylidene)bisphenol, 2,2'difluoro-4,4'-(9H-fluorene-9-ylidene)bisphenol, 2,2'diphenyl-4,4'-(9H-fluorene-9-ylidene)bisphenol, 2,2'dimethoxy-4,4'-(9H-fluorene-9-ylidene)bisphenol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, and dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, hydroxyanthracene, bisphenol, trisphenol, and compounds containing these partial structures, etc.Examples of the resin containing a phenolic hydroxyl group include novolak resins prepared from the above compounds, polyhydroxystyrene polymers, naphthol dicyclopentadiene copolymers described in JP-A-2004-205685, fluorene bisphenol novolak resins described in JP-A-2005-128509, fullerenes having a phenol group described in JP-A-2006-227391, bisphenol compounds and their novolak resins described in JP-A-2006-293298, novolak resins of adamantane phenol compounds described in JP-A-2006-285095, bisnaphthol compounds and their novolak resins described in JP-A-2010-122656, and the like.

[0069] Furthermore, the compound (A) containing a phenolic hydroxyl group is preferably represented by the following general formula (7).

Chemical formula

Chemical formula

Chemical formula

[0070] In the general formula (8) above, the dashed line represents a bond. Z represents an (m + 1)-valent aromatic group having 6 to 20 carbon atoms. Z is an (m + 1)-valent group having a structure obtained by removing (m + 1) hydrogen atoms from an aromatic compound having 6 to 20 carbon atoms. Examples of the aromatic compound having 6 to 20 carbon atoms at this time include benzene, naphthalene, phenanthrene, anthracene, pyrene, biphenyl, toluene, xylene, methylnaphthalene, fluorene, etc., and benzene and naphthalene are preferred from the viewpoints of imparting thermal fluidity and ease of obtaining raw materials. m is an integer of 1 to 5, and in order to obtain good flatness, m is preferably 1 to 3. A is a single bond or -O-(CH2) p -, p is an integer from 1 to 10, and in order to obtain good flatness, -OCH2- with p = 1 is preferably used.

[0071] Examples of the preferred structure of the general formula (8) include the following.

Chemical formula

[0072] Examples of the particularly preferred structure of the general formula (8) include the following formulas (10) to (12).

Chemical formula

[0073] In the resist lower layer film material of the present invention, the terminal group structure of the general formula (8) functions as a thermosetting group. When the substituent A satisfies the relationship of p = 1 and is in the beta position of naphthalene as exemplified by the formulas (10) to (12) which are particularly preferred structures, a mechanism of thermosetting through a ring structure as shown in the following reaction formula is presumed. In this case, before curing, it contributes as a substituent that imparts thermal fluidity, but during curing, a curing reaction occurs via a rigid ring structure, so it becomes possible to achieve both contradictory properties of thermal fluidity and heat resistance. Since the curing reaction proceeds even without an acid generator, the effect of the base generator can be maximized.

Chemical formula

[0074] In the general formula (9) above, the dashed line represents a bond. L represents a single bond or -(CH2) r -, and a single bond or r = 1 is preferred. l is 2 or 3, and from the viewpoint of achieving both flatness and adhesion, it is preferred that l is 2.

[0075] Examples of the preferred structure of the general formula (9) include the following.

Chemical formula

[0076] Examples of the particularly preferred structure of the general formula (9) include the following formulas (13) and (14).

Chemical formula

[0077] In the resist underlayer film material of the present invention, the terminal group structure of the general formula (9) functions as an adhesion group and a film-forming auxiliary group. When having the catechol-type terminal structure of the formulas (13) and (14) exemplified as particularly preferred structures, good flatness is exhibited due to the improved affinity with the substrate, and also, the adhesion to the substrate is improved, thereby during film formation preventing the occurrence of pinholes in the film, peeling from the substrate, and recession (shrinkage) of the film edge.

[0078] Furthermore, when the ratios of the terminal group structures of the general formulas (8) and (9) constituting the terminal group Y in the general formula (7) are a and b, respectively, the relationship a + b = 1.0, 0.70 ≤ a ≤ 0.99, 0.01 ≤ b ≤ 0.30 (when a + b = 100, 70 ≤ a ≤ 99, 1 ≤ b ≤ 30) must be satisfied. More preferably, 0.75 ≤ a ≤ 0.97, 0.03 ≤ b ≤ 0.25, and even more preferably, 0.80 ≤ a ≤ 0.95, 0.05 ≤ b ≤ 0.20. By adjusting the terminal group ratio within the above range, it is possible to achieve both flatness and film-forming properties while maintaining thermosetting properties. The terminal group ratio can be calculated by 1H NMR with respect to the triple bond-containing terminal group / phenolic hydroxyl group-containing terminal group.

[0079] In the general formula (7), since W is an n-valent organic group having 2 to 50 carbon atoms and n is an integer of 1 to 10, W is a 1- to 10-valent organic group having a structure obtained by removing 1 to 10 hydrogen atoms from an organic compound having 2 to 50 carbon atoms. A compound having an organic group W having 2 to 50 carbon atoms with 1 to 10 hydrogen atoms added thereto has at least one or more of each of the terminal structures represented by the general formulas (8) and (9). The organic group represented by W may contain a linear, branched or cyclic saturated or unsaturated hydrocarbon group, aromatic group, heteroaromatic group, ether group, hydroxyl group, ester group, ketone group, amino group, halogen group, sulfide group, carboxyl group, sulfo group, imide group, cyano group, aldehyde group, imino group, urea group, carbamate group, carbonate group, nitro group, sulfone group, etc. In order to achieve both good flatness and sufficient thermosetting properties, n is more preferably 2 to 4.

[0080] Depending on the application, by appropriately selecting W, Y, and n in the compound of the general formula (7), properties such as etching resistance, heat resistance, optical properties, polarity, and flexibility of the resist underlayer film material can be adjusted. Among these, regarding the optical properties, when the resist underlayer film material has appropriate optical properties at a wavelength of 193 nm, the reflected light during exposure in multilayer ArF lithography can be suppressed, and excellent resolution can be achieved. In addition, in order to suppress the reflected light, as the optical constants of the resist underlayer film material, it is generally preferable that the refractive index n is in the range of 1.4 to 1.9 and the extinction coefficient k is in the range of 0.1 to 0.5.

[0081] Furthermore, it is preferable that W in the general formula (7) is an organic group represented by the following general formula (15).

Chemical formula

[0082] Since W in the general formula (7) has the partial structure represented by the general formula (15), thermal fluidity is imparted to the resist underlayer film material of the present invention, and thus good flatness can be imparted.

[0083] In the general formula (15), R 15Examples include a hydrogen atom, a methyl group, a methoxymethyl group, a 1-ethoxyethyl group, a 1-(2-ethylhexyloxy)ethyl group, a 2-tetrahydropyranyl group, an allyl group, a benzyl group, a propargyl group, a formyl group, an acetyl group, a propionyl group, a butyryl group, a hexanoyl group, an icosanoyl group, an acryloyl group, a methacryloyl group, a propioloyl group, a methoxyacetyl group, a benzoyl group, a 4-acetamidobenzoyl group, a carbamoyl group, an N-methylcarbamoyl group, an N,N-dimethylcarbamoyl group, etc. Among these, a hydrogen atom, an acetyl group, and an acryloyl group are preferred, and a hydrogen atom is particularly preferred.

[0084] In the general formula (15), Y 1 represents a single bond or a carbonyl group, and Y 1 is more preferably a carbonyl group.

[0085] W in the general formula (15) 1 is an n-valent organic group having 1 to 47 carbon atoms. The organic group having 1 to 47 carbon atoms of W 1 may be a linear, branched or cyclic saturated or unsaturated hydrocarbon group, an aromatic group, a heteroaromatic group, an ether group, a hydroxyl group, an ester group, a keto group, an amino group, a halogen group, a sulfide group, a carboxyl group, a sulfo group, an imide group, a cyano group, an aldehyde group, an imino group, a urea group, a carbamate group, a carbonate group, a nitro group, or a sulfone group. n is an integer of 1 to 10, and in order to achieve both good flatness and sufficient thermosetting properties, n is more preferably 2 to 4.

[0086] W in the general formula (15) 1 can preferably exemplify structures such as the following formula.

Chemical formula

[0087]

Chemical formula

[0088] Depending on the required performance and application of the present invention, R 15 , W 1 , Y 1 , and n can be appropriately selected to adjust properties such as etching resistance, heat resistance, optical constants, polarity, flexibility, and curability.

[0089] In the present invention, the compound of the general formula (7) may be used alone or in combination of two or more. It may also be used as a mixture containing the compound represented by the general formula (7). When used as a mixture, it is preferably that the compound represented by the general formula (7) occupies 10% by mass or more, more preferably 20% by mass or more, in the total solid content excluding the solvent of the resist underlayer film material. When it is 10% by mass or more, a sufficient blending effect can be obtained.

[0090] For such a resist underlayer film material, the effect of the combination with the base generator can be sufficiently obtained, so that a resist underlayer film excellent in flatness and film-forming property can be formed, and it can be manufactured particularly easily.

[0091] In addition to the compound represented by the general formula (7), another substance can be further blended in the resist underlayer film material of the present invention. The blending substance has a role of mixing with the compound represented by the general formula (7) and improving the film-forming property of spin coating and the embedding property on a substrate having a step. In that case, as the substance that may be mixed, known substances can be used without particular limitation. Specifically, acrylic resins, styrene resins, phenol resins, polyether resins, epoxy resins, and compounds having phenolic hydroxyl groups are preferable. The blending amount of the above blending substance is preferably 1 to 100 parts by mass, more preferably 2 to 50 parts by mass, with respect to 100 parts by mass of the compound represented by the general formula (7). Note that the blending amount of the component (A) in the resist underlayer film material of the present invention can be 3 to 15% by mass.

[0092] [(B) Base generator] The resist underlayer film material of the present invention contains a base generator, and thus can form a resist underlayer film having excellent film-forming properties even on a hydrophobic substrate treated with HMDS, for example. In order to maximize the effect of the base generator, it is preferably not accompanied by an acid generator.

[0093] In the present invention, the base generator refers to a substance whose chemical structure changes upon external stimuli such as light and heat to generate a base, and is also called a "latent base", "base precursor", etc. The generated base may be not only a general base such as ammonia or amine, but also a chemical species having a function of enhancing the ionic property of the phenolic hydroxyl group of component (A).

[0094] (B) The base generator of the component is not particularly limited, and a known base generator can be used as necessary. However, when forming a film using the resist underlayer film material of the present invention, it is assumed that the film-forming property is improved by heating and the ionic property of the phenolic hydroxyl group of component (A) increases the interaction with the substrate during heating. Therefore, it is preferable that the (B) base generator is a compound that exhibits basicity by thermal decomposition. This is because the resist underlayer film material containing such a component (B) can achieve both the thermal fluidity of the film and the interaction with the substrate by adjusting the addition amount of the component (B).

[0095] When a base generator that exhibits basicity by thermal decomposition (also referred to as a thermal base generator) is used as the component (B) in this way, the generated base is the cation that has become excessive in the system due to the evaporation or decomposition of the anion. Specifically, examples include triphenylsulfonium cation and tetrabutylammonium cation. Due to these, the ionic property (polarity) of the phenolic hydroxyl group of the component (A) is enhanced, and even on a substrate that has been hydrophobized by treatment such as HMDS treatment, it interacts with polar groups such as silanol groups present on its surface, improving the wettability of the resist underlayer film material to the substrate and suppressing the occurrence of phenomena such as film edge shrinkage. On the other hand, before heating, that is, before the base is generated, the above-mentioned action does not occur, so the fluidity of the resist underlayer film material itself is maintained. In this way, a resist underlayer film having excellent film-forming properties can be formed.

[0096] Further, it is more preferable that the component (B) base generator is represented by the following general formulas (1), (2), and (3). [Chemical formula] (In the above formula, R 01 ~R 03 each independently represents a linear, branched, or cyclic alkyl group or alkenyl group having 1 to 10 carbon atoms which may be substituted with a heteroatom or in which a heteroatom may be interposed, or an aryl group or aralkyl group having 6 to 18 carbon atoms which may be substituted with a heteroatom or in which a heteroatom may be interposed. Also, any two of R 01 , R 02 and R 03 may be bonded to each other to form a ring together with the sulfur atom in the formula. X - represents an organic or inorganic anion that serves as a counterion. However, X - does not contain OH - . R 04 and R 05is, independently of each other, an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms thereof may be substituted with a linear, branched or cyclic alkyl group or alkoxy group having 1 to 10 carbon atoms. Also, R 04 and R 05 may be bonded to each other to form a ring together with the iodine atom in the formula. R 06 、R 07 、R 08 and R 09 are, independently of each other, a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms which may be substituted with a heteroatom and in which a heteroatom may be interposed, Or alkenyl group as shown, or an aryl group or aralkyl group having 6 to 18 carbon atoms which may be substituted with a heteroatom and in which a heteroatom may be interposed. Also, any two or more of R 06 、R 07 、R 08 and R 09 may be bonded to each other to form a ring together with the nitrogen atom in the formula.)

[0097] R 01 、R 02 and R 03Specific examples of the alkyl group include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups such as a vinyl group, an allyl group, a propenyl group, a butenyl group, a hexenyl group, and a cyclohexenyl group; aryl groups such as a phenyl group, a naphthyl group, and a thienyl group; and aralkyl groups such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group, with an aryl group being preferred. In addition, some of the hydrogen atoms of these groups may be replaced with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms and halogen atoms, or heteroatoms such as oxygen atoms, sulfur atoms and nitrogen atoms may be present, resulting in the formation or presence of a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc.

[0098] R 01 , R 02 and R 03 When any two of the above are bonded to each other directly or via an oxygen atom, a methylene group, a sulfone group, or a carbonyl group, examples of the partial structures include, but are not limited to, a dibenzothiophene skeleton, a phenoxathiin skeleton, and the following partial structures. In the following formula, a substituent may be present at any position on the aromatic ring. [ka]

[0099] More specifically, examples of the sulfonium cation include triphenylsulfonium, 4-hydroxyphenyldiphenylsulfonium, bis(4-hydroxyphenyl)phenylsulfonium, tris(4-hydroxyphenyl)sulfonium, 4-tert-butoxyphenyldiphenylsulfonium, bis(4-tert-butoxyphenyl)phenylsulfonium, tris(4-tert-butoxyphenyl)sulfonium, 3-tert-butoxyphenyldiphenylsulfonium, bis(3-tert-butoxyphenyl)phenylsulfonium, tris(3-tert-butoxyphenyl)sulfonium, 4-tert-butylphenyldiphenylsulfonium, tris(4-tert-butylphenyl)sulfonium, 3,4-di-tert-butoxyphenyldiphenylsulfonium, bis(3,4-di-tert-butoxyphenyl)phenylsulfonium, tris(3,4-di-tert-butoxyphenyl)sulfonium, diphenyl(4-thiophenoxyphenyl)sulfonium, 10-phenylphenoxathiinylium, S-phenyldibenzothiophenium, 4-tert-butoxycarbonylmethyloxyphenyldiphenylsulfonium, tris(4-tert-butoxycarbonylmethyloxyphenyl)sulfonium, (4-tert-butoxyphenyl)bis(4-dimethylaminophenyl)sulfonium, tris(4-dimethylaminophenyl)sulfonium, 2-naphthyldiphenylsulfonium, (4-hydroxy-3,5-dimethylphenyl)diphenylsulfonium, (4-n-hexyloxy-3,5-dimethylphenyl)diphenylsulfonium, and the like. Further examples include 4-methacryloyloxyphenyldiphenylsulfonium, 4-acryloyloxyphenyldiphenylsulfonium, 4-methacryloyloxyphenyldimethylsulfonium, 4-acryloyloxyphenyldimethylsulfonium, (4-methacryloyloxy-3,5-dimethylphenyl)diphenylsulfonium, (4-acryloyloxy-3,5-dimethylphenyl)diphenylsulfonium, and the like.More preferably, triphenylsulfonium, 4-tert-butylphenyldiphenylsulfonium, 4-tert-butoxyphenyldiphenylsulfonium, 10-phenylphenoxathiinylium, S-phenyldibenzothiophenium, etc. may be mentioned. Among these, triphenylsulfonium, 4-tert-butylphenyldiphenylsulfonium, and 4-tert-butoxyphenyldiphenylsulfonium are more preferable.

[0100] R in the general formula (2) 04 and R 05 Specific examples include a phenyl group, a naphthyl group, and the substitution position of the substituent is arbitrary, but a tolyl group, a xylyl group, a trimethylphenyl group, an ethylphenyl group, an isopropylphenyl group, a tert-butylphenyl group, a 1-adamantylphenyl group, a triisopropylphenyl group, a tricyclohexylphenyl group, a methoxyphenyl group, an ethoxyphenyl group, a butoxyphenyl group, a hydroxyphenyl group, a dihydroxyphenyl group, a trimethoxyphenyl group, a methylthiophenyl group, a biphenyl group, a fluorophenyl group, a difluorophenyl group, a bromophenyl group, an iodophenyl group, an N,N-diphenylaminophenyl group, an acetoxyphenyl group, an acetylaminophenyl group, a 2,2,2-trifluoroethoxyphenyl group, a (2-methoxyethoxy)phenyl group, a hydroxynaphthyl group, a dihydroxynaphthyl group, a 2,2,2-trifluoroethoxynaphthyl group, a (2-methoxyethoxy)naphthyl group, etc., but are not limited thereto.

[0101] R 04 and R 05 Preferably, it is an unsubstituted phenyl group or a phenyl group having a substituent selected from a halogen atom, an alkyl group, and an alkoxy group at the para-position of an iodine atom. In particular, a phenyl group, a 4-tert-butylphenyl group, a 4-fluorophenyl group, etc. are preferable.

[0102] R 04 and R 05When they are directly bonded to each other or bonded via an oxygen atom, a methylene group, a sulfone group or a carbonyl group, the partial structures shown below can be exemplified, but are not limited thereto. In the following formulae, a substituent may be present at any position on the aromatic ring.

Chemical formula

[0103] More specifically, examples of the iodonium cation include, but are not limited to, those shown below. In the following formulae, tBu is a tert-butyl group and Ph is a phenyl group.

Chemical formula

[0104] Examples of the ammonium cation represented by the general formula (3) include ammonium cations obtained by proton addition to a nitrogen atom of ammonia, primary, secondary and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, etc., and quaternary ammonium cations.

[0105] Specifically, examples of primary aliphatic ammonium compounds include methylammonium, ethylammonium, n-propylammonium, isopropylammonium, n-butylammonium, isobutylammonium, sec-butylammonium, tert-butylammonium, pentylammonium, tert-amylammonium, cyclopentylammonium, hexylammonium, cyclohexylammonium, heptylammonium, octylammonium, nonylammonium, decylammonium, dodecylammonium, cetylammonium, aminomethylammonium, 2-aminoethylammonium, etc. Examples of secondary aliphatic ammonium compounds include dimethylammonium, diethylammonium, di-n-propylammonium, diisopropylammonium, di-n-butylammonium, diisobutylammonium, di-sec-butylammonium, dipentylammonium, dicyclopentylammonium, dihexylammonium, dicyclohexylammonium, diheptylammonium, dioctylammonium, dinonylammonium, didecylammonium, didodecylammonium, dicetylammonium, methyl(methylamino)methylammonium, methyl-2-(methylamino)ethylammonium, etc. Examples of tertiary aliphatic ammonium compounds include trimethylammonium, triethylammonium, tri-n-propylammonium, triisopropylammonium, tri-n-butylammonium, triisobutylammonium, tri-sec-butylammonium, tripentylammonium, tricyclopentylammonium, trihexylammonium, tricyclohexylammonium, triheptylammonium, trioctylammonium, trinonylammonium, tridecylammonium, tridodecylammonium, tricetylammonium, dimethyl(dimethylamino)methylammonium, dimethyl(2-dimethylaminoethyl)ammonium, etc.

[0106] Examples of the mixed ammonium compounds include dimethylethylammonium, methylpropylammonium, benzylammonium, phenethylammonium, benzyldimethylammonium and the like. Specific examples of the aromatic ammonium compounds and the heterocyclic ammonium compounds include anilinium derivatives (e.g., anilinium, N-methylanilinium, N-ethylanilinium, N-propylanilinium, N,N-dimethylanilinium, 2-methylanilinium, 3-methylanilinium, 4-methylanilinium, ethylanilinium at any substitution position, propylanilinium at any substitution position, trimethylanilinium at any substitution position, 2-nitroanilinium, 3-nitroanilinium, 4-nitroanilinium, 2,4-dinitroanilinium, 2,6-dinitroanilinium, 3,5-dinitroanilinium, N,N-dimethyltoluidinium at any substitution position), diphenyl(p-tolyl)ammonium, methyldiphenylammonium, triphenylammonium, aminophenylammonium at any substitution position, naphthylammonium, aminonaphthylammonium at any substitution position, pyrrolinium derivatives (e.g., pyrrolinium, 2H-pyrrolinium, 1-methylpyrrolinium, 2,4-dimethylpyrrolinium, 2,5-dimethylpyrrolinium, N-methylpyrrolinium, etc.), oxazolium derivatives (e.g., oxazolium, isoxazolium, etc.), thiazolium derivatives (e.g., thiazolium, isothiazolium, etc.), imidazolium derivatives (e.g., imidazolium, 4-methylimidazolium, 4-methyl-2-phenylimidazolium, etc.), pyrazolium derivatives, furazanium derivatives, pyrrolinium derivatives (e.g., pyrrolinium, 2-methyl-1-pyrrolinium, etc.), pyrrolidinium derivatives (e.g., pyrrolidinium, N-methylpyrrolidinium, pyrrolidinonium, N-methylpyrrolidonium, etc.), imidazolinium derivatives, imidazolidinium derivatives, pyridinium derivatives (e.g., pyridinium, methylpyridinium, ethylpyridinium, propylpyridinium, butylpyridinium, 4-(1-butylpentyl)pyridinium, dimethylpyridinium, trimethylpyridinium, triethylpyridinium, phenylpyridinium, 3-methyl-2-phenylpyridinium, 4-tert-butylpyridinium, diphenylpyridinium, benzylpyridinium, methoxypyridinium, butoxypyridinium, dimethoxypyridinium, 4-pyrrolidinopyridinium, 2-(1-ethylpropyl)pyridinium, aminopyridinium, dimethylaminopyridinium, etc.), pyridazinium derivatives, pyrimidinium derivatives, pyrazinium derivatives, pyrazolinium derivatives, pyrazolidinium derivatives, piperidinium derivatives, piperazinium derivatives, morpholinium derivatives, indolinium derivatives, isoindolinium derivatives, 1H-indazolinium derivatives, indolinium derivatives, quinolinium derivatives (e.g., quinolinium), isoquinolinium derivatives, cinnolinium derivatives, quinazolinium derivatives, quinoxalinium derivatives, phthalazinium derivatives, purinium derivatives, pteridinium derivatives, carbazolium derivatives, phenanthridinium derivatives, acridinium derivatives, phenazinium derivatives, 1,10-phenanthrolinium derivatives, etc. are exemplified.,

[0107] Furthermore, examples of the nitrogen-containing compound having a carboxy group include carboxyphenylammonium, carboxyindolinium, amino acid derivatives (e.g., proton addition products such as nicotinic acid, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine, methionine, phenylalanine, threonine, lysine, 3-aminopyrazine-2-carboxylic acid, methoxyalanine, etc.), and examples of the nitrogen-containing compound having a sulfonyl group include 3-pyridinium sulfonic acid. Examples of the nitrogen-containing compound having a hydroxy group, the nitrogen-containing compound having a hydroxyphenyl group, and the alcoholic nitrogen-containing compound include 2-hydroxypyridinium, hydroxyanilinium at any substitution position, hydroxy - methyl - anilinium, hydroxyquinolinium, dihydroxyquinolinium, 2-hydroxyethylammonium, bis(2-hydroxyethyl)ammonium, tris(2-hydroxyethyl)ammonium, ethylbis(2-hydroxyethyl)ammonium, diethyl(2-hydroxyethyl)ammonium, hydroxypropylammonium, bis(hydroxypropyl)ammonium, tris(hydroxypropyl)ammonium, 4-(2-hydroxyethyl)morpholinium, 2-(2-hydroxyethyl)pyridinium, 1-(2-hydroxyethyl)piperazinium, 1-[2-(2-hydroxyethoxy)ethyl]piperazinium, (2-hydroxyethyl)piperazinium, 1-(2-hydroxyethyl)pyrrolidinium, 1-(2-hydroxyethyl)-2-pyrrolidino niu m, 2,3-dihydroxypropylpiperidinium, 2,3-dihydroxypropyl pyro lysidinium, 8-hydroxyhylidinium, 3-hydroxyquinuclidinium, etc. are exemplified.

[0108] Specific examples of the quaternary ammonium salt include tetramethylammonium, triethylmethylammonium, tetraethylammonium, tetrabutylammonium, tetraoctylammonium, didecyldimethylammonium, tridecylmethylammonium, hexadecyltrimethylammonium, stearyltrimethylammonium, benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, 2-hydroxyethyltrimethylammonium, and the like.

[0109] As the ammonium cation, a quaternary ammonium cation is preferred, and particularly a tetramethylammonium cation, a tetraethylammonium cation, and a tetrabutylammonium cation are preferred.

[0110] At this time, X in the general formulas (1), (2), and (3) - is more preferably a structure represented by any of the following general formulas (4), (5), and (6), or any one of chloride ion, bromide ion, iodide ion, fluoride ion, cyanide ion, nitrate ion, and nitrite ion.

Chemical formula

[0111] Specific examples of the carboxylic acid anion represented by the general formula (4) include formate anion, acetate anion, propionate anion, butyrate anion, isobutyrate anion, valerate anion, isovalerate anion, pivalate anion, hexanoate anion, octanoate anion, cyclohexanecarboxylate anion, cyclohexylacetate anion, laurate anion, myristate anion, palmitate anion, stearate anion, phenylacetate anion, diphenylacetate anion, phenoxyacetate anion, mandelate anion, benzoylformate anion, cinnamate anion, dihydrocinnamate anion, benzoate anion, methylbenzoate anion, salicylate anion, naphthalenecarboxylate anion, anthracenecarboxylate anion, anthraquinonecarboxylate anion, hydroxyacetate anion, pivalinate anion, lactate anion, methoxyacetate anion, 2-(2-methoxyethoxy)acetate anion, 2-(2-(2-methoxyethoxy)ethoxy)acetate anion, diphenolate anion, monochloroacetate anion, dichloroacetate anion, trichloroacetate anion, trifluoroacetate anion, pentafluoropropionate anion, heptafluorobutyrate anion, 2-hydroxy-2,2-bis(trifluoromethyl)acetate anion, etc. Also, monoanions of dicarboxylic acids such as succinic acid, tartaric acid, glutaric acid, pimelic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid can be exemplified.

[0112] Specific examples of the arenesulfonate anion represented by the general formula (5) include benzenesulfonate, 4-toluenesulfonate, 2-toluenesulfonate, xylenesulfonate at any substitution position, trimethylbenzenesulfonate, mesitylenesulfonate, 4-methoxybenzenesulfonate, 4-ethylbenzenesulfonate, 2,4,6-triisopropylbenzenesulfonate, 1-naphthalenesulfonate, 2-naphthalenesulfonate, anthraquinone-1-sulfonate, anthraquinone-2-sulfonate, 4-(4-methylbenzenesulfonyloxy)benzenesulfonate, 3,4-bis(4-methylbenzenesulfonyloxy)benzenesulfonate, 6-(4-methylbenzenesulfonyloxy)naphthalene-2-sulfonate, 4-phenyloxybenzenesulfonate, 4-diphenylmethylbenzenesulfonate, 2,4-dinitrobenzenesulfonate, dodecylbenzenesulfonate, and the like.

[0113] Specific examples of the alkanesulfonate anion represented by the general formula (6) include methanesulfonate, ethanesulfonate, propanesulfonate, butanesulfonate, pentanesulfonate, hexanesulfonate, cyclohexanesulfonate, octanesulfonate, 10-camphorsulfonate, and the like.

[0114] Furthermore, X in the general formulas (1), (2) and (3) - is more preferably such that the boiling point of the conjugate acid X-H thereof is 200 °C or lower.

[0115] X in the general formulas (1), (2) and (3) - is particularly preferably a trifluoroacetate anion, a pentafluoropropionate anion, a 2-hydroxy-2,2-bis(trifluoromethyl)acetate anion, a chloride ion, or a nitrate ion.

[0116] Examples of the (B) base generator include, but are not limited to, any combination of the specific examples of the cations and anions described above. Further, preferred structures include those shown below. In the following formulas, tBu represents a tert-butyl group. [Chemical formula]

[0117] The (B) base generator can be used alone or in combination of two or more to exhibit basicity in accordance with the firing temperature of the resist underlayer film material, and can appropriately adjust the balance between film-forming properties and flatness on a hydrophobic substrate. When adding a base generator, the addition amount is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 3 parts by mass, based on 100 parts by mass of the compound or resin ((A) component) of (A). If the addition amount of the base generator is within the above range, a sufficient film-forming property improvement effect can be obtained, and there is no fear of problems such as deterioration of in-plane uniformity of the film due to decomposition and sublimation or a decrease in the curability of the compound or resin due to basicity.

[0118] [(C) Organic solvent] The (C) organic solvent that can be used in the resist underlayer film material of the present invention is not particularly limited as long as it can dissolve one or more of (A) a compound or resin containing a phenolic hydroxyl group and (B) a base generator, and preferably can dissolve (D) a surfactant, (E) a crosslinking agent, (F) a plasticizer, and (G) a pigment described later.

[0119] Specifically, the solvents described in paragraphs

[0091] to

[0092] of JP-A-2007-199653 can be added. More specifically, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and γ-butyrolactone, or a mixture containing one or more of these is preferably used.

[0120] The blending amount of the organic solvent is preferably adjusted according to the set film thickness of the resist underlayer film. Usually, it is in the range of 100 to 50,000 parts by mass with respect to 100 parts by mass of the compound or resin ((A) component) containing a phenolic hydroxyl group ((A) component).

[0121] In the resist underlayer film material of the present invention, it is preferable that the (C) organic solvent is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher (hereinafter also referred to as "high-boiling solvent").

[0122] Specific examples of the organic solvent having a boiling point of less than 180°C include propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, and cyclohexanone.

[0123] As the organic solvent having a boiling point of 180°C or higher, there are no particular restrictions as long as it can dissolve each component of the resist underlayer film material of the present invention, such as hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc. Specific examples include 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, ethylene glycolMonohexyl 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, triethylene glycol diacetate, γ-butyrolactone, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, dibutyl adipate, etc. can be exemplified, and these may be used alone or in combination.

[0124] Organic solvents with a boiling point of 180°C or higher can be appropriately selected from the above-mentioned ones according to the temperature for heat-treating the resist underlayer film material of the present invention. The boiling point of the organic solvent with a boiling point of 180°C or higher is preferably 180°C to 300°C, and more preferably 200°C to 300°C. With such a boiling point, there is no fear that the volatilization during baking (heat treatment) will be too fast due to too low a boiling point, so sufficient heat fluidity can be obtained during film formation, and it is considered that a resist underlayer film excellent in embedding / planarization characteristics can be formed. Also, with such a boiling point, there is no fear that it will remain in the film without volatilizing even after baking because the boiling point is too high, which may adversely affect the film physical properties such as etching resistance.

[0125] In addition, when using an organic solvent with a boiling point of 180°C or higher, the blending amount is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the organic solvent with a boiling point of less than 180°C. With such a blending amount, there is no fear that the blending amount is too small to impart sufficient heat fluidity during baking, or that the blending amount is too large and remains in the film, leading to deterioration of film physical properties such as etching resistance, which is preferable.

[0126] [(D) Surfactant] (D) Surfactant can be added to the resist underlayer film material of the present invention to improve the coatability in spin coating. As the surfactant, for example, those described in

[0142] to

[0147] in JP-A-2009-269953 can be used. When adding the surfactant, the addition amount is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the component (A).

[0127] [(E) Crosslinking agent] In addition, in order to enhance the curability and further suppress the intermixing with the upper layer film, a (E) crosslinking agent can also be added to the resist underlayer film material of the present invention. The crosslinking agent is not particularly limited, and various known types of crosslinking agents can be widely used. As an example, melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, phenol-based crosslinking agents (for example, methylol or alkoxymethyl type crosslinking agents of polynuclear phenols) can be exemplified. When adding the crosslinking agent, the addition amount is preferably 1 to 60 parts by mass, more preferably 10 to 50 parts by mass, based on 100 parts by mass of the component (A).

[0128] As melamine-based crosslinking agents, specifically, hexamethoxymethylmelamine, hexabutoxymethylmelamine, their alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified. As glycoluril-based crosslinking agents, specifically, tetramethoxymethylglycoluril, tetrabutoxymethylglycoluril, their alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified. As benzoguanamine-based crosslinking agents, specifically, tetramethoxymethylbenzoguanamine, tetrabutoxymethylbenzoguanamine, their alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified. As urea-based crosslinking agents, specifically, dimethoxymethyldimethoxyethyleneurea, its alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified. As β-hydroxyalkylamide-based crosslinking agents, specifically, N,N,N’,N’-tetra(2-hydroxyethyl)adipic acid amide can be exemplified. As isocyanurate-based crosslinking agents, specifically, triglycidyl isocyanurate, triallyl isocyanurate can be exemplified. As aziridine-based crosslinking agents, specifically, 4,4’-bis(ethyleneiminocarbonylamino)diphenylmethane, 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] can be exemplified. As oxazoline-based crosslinking agents, specifically, 2,2’-isopropylidenebis(4-benzyl-2-oxazoline), 2,2’-isopropylidenebis(4-phenyl-2-oxazoline), 2,2’-isopropylidenebis(4-phenyl-2-oxazoline), 2,2’-methylenebis-4,5-diphenyl-2-oxazoline, 2,2’-methylenebis-4-phenyl-2-oxazoline, 2,2’-methylenebis-4-tert-butyl-2-oxazoline, 2,2’-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), 2-isopropenyl oxazoline copolymer can be exemplified.Specific examples of the epoxy crosslinking agent include diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, poly(glycidyl methacrylate), trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0129] In order to maximize the effect of the base generator, a polynuclear phenol crosslinking agent that can proceed with the crosslinking reaction even without an acid generator is more preferable. Furthermore, since the polynuclear phenol crosslinking agent itself also contains phenolic hydroxyl groups, a higher film-forming property improvement effect is expected by the action of the base generator. Specific examples of the polynuclear phenol crosslinking agent include compounds represented by the following general formula (16).

Chemical formula

[0130] Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. q is an integer of 1 to 5, and more preferably 2 or 3. Specific examples of Q include groups obtained by removing q hydrogen atoms from methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane. R 16is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, an octyl group, an ethylhexyl group, a decyl group, and an eicosanyl group. A hydrogen atom or a methyl group is preferred.

[0131] As examples of the compound represented by the general formula (16), specifically, the following compounds can be exemplified. Among these, hexamethoxymethylated products of triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred from the viewpoints of curability of the resist underlayer film and improvement in film thickness uniformity.

[0132] [Chemical formula]

[0133] [Chemical formula] (In the formula, R 16 is the same as described above)

[0134] [(F) Plasticizer] In addition, a (F) plasticizer can be added to the resist underlayer film material of the present invention in order to further improve the planarization / embedding characteristics. The plasticizer is not particularly limited, and various known types of plasticizers can be widely used. As an example, low molecular compounds such as phthalic acid esters, adipic acid esters, phosphoric acid esters, trimellitic acid esters, and citric acid esters, and polymers such as polyether-based, polyester-based, and polyacetal-based polymers described in JP-A 2013-253227 can be exemplified. The addition amount when adding the plasticizer is preferably 5 to 500 parts by mass, more preferably 10 to 200 parts by mass, based on 100 parts by mass of the component (A).

[0135] [(G) Dye] In addition, in order to further improve the resolution during patterning of multilayer lithography, a (G) dye can be added to the resist underlayer film material of the present invention. The dye is not particularly limited as long as it is a compound having appropriate absorption at the exposure wavelength, and various known compounds can be widely used. As an example, benzenes, naphthalenes, anthracenes, phenanthrenes, pyrenes, isocyanuric acids, and triazines can be exemplified. When adding the dye, the addition amount is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the component (A).

[0136] <Pattern formation method> In addition, in the present invention, a method for forming a pattern on a substrate to be processed, (I-1) A step of forming a resist underlayer film by applying the above resist underlayer film material on a substrate to be processed and then performing a heat treatment, (I-2) A step of forming a resist upper layer film using a photoresist material on the above resist underlayer film, (I-3) A step of forming a pattern on the above resist upper layer film by pattern exposure and then developing with a developer, (I-4) A step of transferring the pattern to the above resist underlayer film by dry etching using the resist upper layer film on which the pattern is formed as a mask, and (I-5) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed A pattern formation method having the above steps (two-layer resist process) is provided.

[0137] Furthermore, a method for forming a pattern on a substrate to be processed, (II-1) A step of forming a resist underlayer film by applying the above resist underlayer film material on a substrate to be processed and then performing a heat treatment, (II-2) A step of forming a resist intermediate film on the above resist underlayer film, (II-3) A step of forming a resist upper layer film using a photoresist material on the above resist intermediate film, (II-4) After pattern-exposing the resist upper layer film, developing it with a developer to form a pattern in the resist upper layer film; (II-5) Using the resist upper layer film on which the pattern has been formed as a mask, transferring the pattern to the resist intermediate film by dry etching; (II-6) Using the resist intermediate film to which the pattern has been transferred as a mask, transferring the pattern to the resist lower layer film by dry etching, and (II-7) Using the resist lower layer film on which the pattern has been formed as a mask to process the substrate to be processed and form a pattern on the substrate to be processed To provide a pattern forming method (three-layer resist process) having the above steps.

[0138] In addition, a method for forming a pattern on a substrate to be processed, comprising: (III-1) After coating the resist lower layer film material on the substrate to be processed, heat-treating to form a resist lower layer film; (III-2) Forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist lower layer film; (III-3) Forming an organic thin film on the inorganic hard mask intermediate film; (III-4) Using a photoresist material to form a resist upper layer film on the organic thin film; (III-5) After pattern-exposing the resist upper layer film, developing it with a developer to form a pattern in the resist upper layer film; (III-6) Using the resist upper layer film on which the pattern has been formed as a mask, transferring the pattern to the organic thin film and the inorganic hard mask intermediate film by dry etching; (III-7) Using the inorganic hard mask intermediate film to which the pattern has been transferred as a mask, transferring the pattern to the resist lower layer film by dry etching, and (III-8) Using the resist lower layer film on which the pattern has been formed as a mask to process the substrate to be processed and form a pattern on the substrate to be processed To provide a pattern formation method (four-layer resist process) having

[0139] The thickness of the resist underlayer film used in the present invention is appropriately selected, but it is preferably 2 to 20,000 nm, particularly preferably 50 to 15,000 nm. In the case of a resist underlayer film for a three-layer process, a resist intermediate film (intermediate layer film) containing silicon and a resist upper layer film not containing silicon can be formed thereon. In the case of a resist underlayer film for a two-layer process, a resist upper layer film containing silicon or a resist upper layer film not containing silicon can be formed thereon.

[0140] The pattern formation method of the present invention is suitably used for multi-layer resist processes such as a silicon-containing two-layer resist process, a three-layer resist process using a silicon-containing intermediate film, or a four-layer resist process using a silicon-containing intermediate film and an organic thin film, and a two-layer resist process not containing silicon.

[0141] [Three-layer resist process] Regarding the pattern formation method of the present invention, the three-layer resist process will be described below as an example, but it is not limited to this process. In this case, a resist underlayer film is formed on a substrate using the above resist underlayer film material, a resist intermediate film is formed on the resist underlayer film using a resist intermediate film material containing silicon atoms, and a resist upper layer film is formed on the resist intermediate film using a resist upper layer film material of a photoresist composition to form a multi-layer resist film. After exposing the pattern circuit region of the resist upper layer film, it is developed with a developer to form a resist pattern on the resist upper layer film. The resist intermediate film is etched using the resist upper layer film on which the pattern is formed as a mask, the resist underlayer film is etched using the resist intermediate film on which the pattern is formed as a mask, and further, the substrate can be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate.

[0142] Since the resist intermediate film containing silicon atoms exhibits etching resistance to oxygen gas or hydrogen gas, as described above, it is preferable to perform the etching of the resist underlayer film using the resist intermediate film as a mask with an etching gas mainly composed of oxygen gas or hydrogen gas.

[0143] Also, in the pattern formation method of the present invention, at least, a resist underlayer film is formed on a substrate using the above resist underlayer film material, 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 resist upper layer film material composed of a photoresist composition, after exposing the pattern circuit region of the resist upper layer film, developing with a developer to form a resist pattern on the resist upper layer film, using the obtained resist pattern as an etching mask to etch the inorganic hard mask intermediate film, using the obtained inorganic hard mask intermediate film pattern as an etching mask to etch the resist underlayer film, and using the obtained resist underlayer film pattern as a mask to process the substrate to form a pattern on the substrate.

[0144] As described above, when forming an inorganic hard mask intermediate film on the 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. As a method for forming the nitride film, it is described in JP-A-2002-334869 and WO2004 / 066377. The film thickness of the inorganic hard mask is 5 to 200 nm, preferably 10 to 100 nm, and among them, the SiON film having a high effect as an antireflection film is most preferably used for ArF exposure applications.

[0145] As the silicon-containing resist intermediate film in a three-layer resist process, a polysilsesquioxane-based intermediate film can be preferably used. The polysilsesquioxane-based intermediate film can easily provide an antireflection effect in excimer exposure, thereby suppressing reflected light during pattern exposure of the resist upper layer film and having the advantage of excellent resolution. In particular, for 193 nm exposure, when a material containing a large amount of aromatic groups is used as the resist lower layer film, the k value increases and the substrate reflection increases. However, by suppressing reflection with the resist intermediate film, the substrate reflection can be reduced to 0.5% or less. As the resist intermediate film having an antireflection effect, anthracene for 248 nm and 157 nm exposure, and a polysilsesquioxane having an absorptive group having a phenyl group or a silicon-silicon bond pendant and crosslinked by an acid or heat is preferably used for 193 nm exposure.

[0146] In this case, forming the silicon-containing resist intermediate film by spin coating is simpler and more cost-effective than by CVD method.

[0147] The resist upper layer film in the three-layer resist film can be either positive or negative, and the same photo resist composition as the commonly used one can be used. When forming the resist upper layer film with the above photo resist composition, the spin coating method is preferably used in the same manner as when forming the above resist lower layer film. After spin coating the photo resist composition, pre-baking is performed, and the range of 60 to 180 °C for 10 to 300 seconds is preferred. Thereafter, exposure is performed according to a conventional method, post-exposure bake (PEB) and development are performed to obtain a resist pattern. The thickness of the resist upper layer film is not particularly limited, but 30 to 500 nm, particularly 50 to 400 nm is preferred.

[0148] In addition, as the exposure light, high energy rays with a wavelength of 300 nm or less can be mentioned, specifically, excimer lasers of 248 nm, 193 nm, 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays with a wavelength of less than 3 nm, etc.

[0149] Next, etching is performed using the obtained resist pattern as a mask. The etching of the resist intermediate film in the three-layer process is performed using a fluorocarbon-based gas with the resist pattern as a mask. Next, using the resist intermediate film pattern as a mask, the lower resist film is etched using oxygen gas or hydrogen gas.

[0150] The etching of the next substrate to be processed can also be performed by a conventional method. For example, if the substrate is SiO2, SiN, or a silica-based low dielectric constant insulating film, etching mainly using a fluorocarbon-based gas is performed. For p-Si, Al, or W, etching mainly using a chlorine-based or bromine-based gas is performed. When the substrate is etched with a fluorocarbon-based gas, the silicon-containing intermediate film in the three-layer process is peeled off simultaneously with the substrate processing. When the substrate is etched with a chlorine-based or bromine-based gas, it is necessary to separately perform dry etching peeling with a fluorocarbon-based gas or the like after the substrate processing to peel off the silicon-containing intermediate film.

[0151] Note that as the substrate to be processed, a processed layer is formed on the substrate. The substrate is not particularly limited, and materials different from the processed layer such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, and Al are used. As the processed layer, various Low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, TiN, W-Si, Al, Cu, and Al-Si, and their stopper films are used, and they are usually formed to a thickness of 50 to 10,000 nm, particularly 100 to 5,000 nm. Furthermore, as the substrate to be processed, a substrate having a static contact angle with water of 50° or more can be preferably used.

[0152] The pattern formation method of the present invention is also suitable for processing a stepped substrate having a structure or step with a height of 30 nm or more. By forming the lower resist film of the present invention on the stepped substrate and performing embedding and planarization, it becomes possible to make the film thicknesses of the subsequently formed resist intermediate film and resist upper layer film uniform. Therefore, it is easy to secure the depth of focus margin (DOF) during photolithography, which is very preferable. Furthermore, it is also useful when a substrate having a static contact angle with water of 50° or more is used as the substrate to be processed.

[0153] An example of a three-layer resist process is specifically shown as follows with reference to FIG. 1. In the case of a three-layer resist process, as shown in FIG. 1(A), after forming a lower resist film 3 on a layer to be processed 2 laminated on a substrate 1, a middle resist film 4 is formed, and then an upper resist film 5 is formed thereon.

[0154] Next, as shown in FIG. 1(B), a required portion 6 of the upper resist film is exposed, and PEB (post-exposure bake) and development are performed to form an upper resist film pattern 5a (FIG. 1(C)). Using this obtained upper resist film pattern 5a as a mask, the middle resist film 4 is etched using a CF-based gas to form a middle resist film pattern 4a (FIG. 1(D)). After removing the upper resist film pattern 5a, using this obtained middle resist film pattern 4a as a mask, the lower resist film 3 is etched with oxygen-based or hydrogen-based plasma to form a lower resist film pattern 3a (FIG. 1(E)). Further, after removing the middle resist film pattern 4a, using the lower resist film pattern 3a as a mask, the layer to be processed 2 is etched to form a pattern 2a (FIG. 1(F)).

[0155] When using an inorganic hard mask intermediate film, the middle resist film 4 is an inorganic hard mask intermediate film, and when laying an organic thin film, an organic thin film layer is provided between the middle resist film 4 and the upper resist film 5. The etching of the organic thin film may be performed continuously prior to the etching of the middle resist film 4, or the organic thin film alone may be etched and then the etching of the middle resist film 4 may be performed by changing the etching apparatus or the like.

[0156] [Four-Layer Resist Process] Furthermore, the present invention can also be suitably used in a four-layer resist process using an organic thin film. In this case, at least, a resist underlayer film is formed on a substrate using the above resist underlayer film material, 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 thin film is formed on the inorganic hard mask intermediate film, a resist upper layer film is formed on the organic thin film using a resist upper layer film material composed of a photoresist composition. After exposing the pattern circuit region of the resist upper layer film, it is developed with a developer to form a resist pattern on the resist upper layer film. The obtained resist pattern is used as an etching mask to etch the organic thin film and the inorganic hard mask intermediate film, the obtained inorganic hard mask intermediate film pattern is used as an etching mask to etch the resist underlayer film, and the obtained resist underlayer film pattern is used as a mask to process the substrate to form a pattern on the substrate.

[0157] A photoresist film may be formed as a resist upper layer film on the resist intermediate film. However, as described above, an organic thin film may be spin-coated on the resist intermediate film and a photoresist film may be formed thereon. When a SiON film is used as the resist intermediate film and an organic antireflection film (BARC) having an absorption group at the exposure wavelength is used as the organic thin film, it is possible to suppress reflection even in immersion lithography with a high NA exceeding 1.0 by the two-layer antireflection films of the SiON film and the organic thin film in excimer exposure. Another merit of forming the organic thin film is that it has an effect of reducing the footing of the photoresist pattern directly on the SiON. Also, when an adhesion film (ADL) excellent in affinity with the upper photoresist is used as the organic thin film, it is also an advantage that the pattern collapse of the photoresist can be suppressed.

[0158] <Resist Underlayer Film Forming Method> The present invention provides a method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process. The method includes spin-coating the above-described resist underlayer film material on a substrate to be processed, and curing the substrate coated with the resist underlayer film material by heat treatment at a temperature in the range of 100°C or higher and 600°C or lower for 10 to 600 seconds to form a resist underlayer film (cured film).

[0159] Further, the present invention provides a method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process. The method includes spin-coating the above-described resist underlayer film material on a substrate to be processed, and curing the substrate coated with the resist underlayer film material by heat treatment in an atmosphere having an oxygen concentration of 1% by volume or more and 21% by volume or less to form a resist underlayer film (cured film).

[0160] Alternatively, the present invention provides a method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process. The method includes spin-coating the above-described resist underlayer film material on a substrate to be processed, and curing the substrate coated with the resist underlayer film material by heat treatment in an atmosphere having an oxygen concentration of less than 1% by volume to form a resist underlayer film (cured film).

[0161] In the method for forming a resist underlayer film of the present invention, the above-mentioned resist underlayer film material is coated on a substrate to be processed using a spin coating method or the like. By using a spin coating method or the like, good embedding characteristics can be obtained. After spin coating, the solvent is evaporated, and baking is performed to promote the crosslinking reaction in order to prevent mixing with the resist upper layer film or the resist intermediate film. The baking is carried out within a temperature range of 100°C or higher and 600°C or lower, preferably 100°C or higher and 300°C or lower, more preferably 150°C or higher and 280°C or lower, and is carried out for 10 seconds to 600 seconds, preferably within the range of 10 to 300 seconds. By appropriately adjusting the baking temperature and time within the above range, flattening / embedding characteristics and curing characteristics suitable for the application can be obtained. When the baking temperature is 100°C or higher, curing proceeds sufficiently and mixing with the upper layer film or the intermediate film does not occur. If the baking temperature is 600°C or lower, thermal decomposition of the base resin can be suppressed, the film thickness does not decrease, and the film surface becomes uniform.

[0162] As the atmosphere during baking, either an oxygen-containing atmosphere such as in air (oxygen concentration 1% by volume to 21% by volume) or a non-oxygen atmosphere such as in nitrogen can be selected as needed. For example, when the substrate to be processed is easily oxidized by air, damage to the substrate can be suppressed by heat-treating in an atmosphere with an oxygen concentration of less than 1% by volume (non-oxygen atmosphere) to form a cured film.

[0163] Also, in the method for forming a resist underlayer film of the present invention, it is also preferable to use, as the substrate to be processed, a substrate having a structure or step with a height of 30 nm or more. The method for forming a resist underlayer film of the present invention is particularly useful when forming a flat organic film without voids on a substrate having a structure or step with a height of 30 nm or more. Furthermore, it is also useful when using, as the substrate to be processed, a substrate having a static contact angle with water of 50° or more.

Examples

[0164] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited by these descriptions. The measurement of molecular weight and dispersity was carried out by the following methods. The weight average molecular weight (Mw) in terms of polystyrene and the dispersity (Mw / Mn) were determined by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent. The introduction ratio of the end group was calculated by 1H NMR.

[0165] Synthesis Example: Synthesis of Compounds for Resist Lower Layer Film Material For the synthesis of the compounds (D1) to (D12) for the resist underlayer film material and the compound (R1) for the comparative example, the following triple bond-containing compounds: compound groups A (A1) to (A3), phenolic hydroxyl group-containing carboxylic acid compounds: compound groups B (B1) to (B4), and epoxy compounds: compound groups C (C1) to (C5) were used.

[0166] [Chemical formula]

[0167] [Chemical formula]

[0168] [Chemical formula]

[0169] [Synthesis Example 1] Synthesis of Compound (D1) [Chemical formula] 12.44 g of a triple bond-containing carboxylic acid compound (A1), 1.46 g of a phenolic hydroxyl group-containing carboxylic acid compound (B1), 16.10 g of an epoxy compound (C1) and 60 g of 2-methoxy-1-propanol were stirred at an internal temperature of 100 °C under a nitrogen atmosphere to form a homogeneous solution. Then, 1.00 g of benzyltriethylammonium chloride was added, and the mixture was stirred at an internal temperature of 110 °C for 12 hours. After cooling to room temperature, 200 ml of methyl isobutyl ketone was added, and the mixture was washed twice with 100 g of 1 wt% aqueous ammonia solution, twice with 100 g of 3% aqueous nitric acid solution, and five times with 100 g of ultrapure water in this order. The organic layer was dried under reduced pressure to obtain compound (D1). When the weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, Mw = 980 and Mw / Mn = 1.03. The terminal group ratio calculated by 1H NMR was triple bond-containing terminal group / phenolic hydroxyl group-containing terminal group = 90.8 / 9.2.

[0170] [Synthesis Examples 2 to 13] Synthesis of Compounds (D2) to (D12) and Comparative Compound (R1) Compounds (D2) to (D12) and (R1) as shown in Table 2 were obtained as products under the same conditions as in Synthesis Example 1, except that the compound groups A, B, and C shown in Table 1 were used. The weight average molecular weight (Mw), dispersity (Mw / Mn), and terminal group ratio (triple bond-containing group / phenolic hydroxyl group-containing group) of these compounds were determined and shown in Table 2.

[0171] [Table 1]

[0172] [Table 2]

[0173] [Synthesis Example 14] Synthesis of Comparative Compound (R2) [Chemical Formula] 19.86 g of a triple bond-containing carboxylic acid compound (A2), 1.54 g of acetylglycine, 10.00 g of an epoxy compound (C5), and 60 g of 2-methoxy-1-propanol were stirred at an internal temperature of 100 °C under a nitrogen atmosphere to form a homogeneous solution. Then, 1.00 g of benzyltriethylammonium chloride was added, and the mixture was stirred at an internal temperature of 110 °C for 12 hours. After cooling to room temperature, 200 ml of methyl isobutyl ketone was added, and the mixture was washed successively with 100 g of 1 wt% aqueous ammonia solution twice, 100 g of 3% aqueous nitric acid solution twice, and 100 g of ultrapure water five times. The organic layer was dried under reduced pressure to obtain a comparative compound (R2). When the weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, Mw = 1100 and Mw / Mn = 1.04. The terminal group ratio calculated by 1H NMR was triple bond-containing terminal group / amide group-containing terminal group = 87.5 / 12.5.

[0174] [Synthesis Example 15] Synthesis of Comparative Polymer (R3) [Chemical formula] 78.8 g of 2,7-dipropargyloxy naphthalene, 21.6 g of 37% formalin solution, and 250 g of 1,2-dichloroethane were made into a homogeneous solution at a liquid temperature of 70 °C under a nitrogen atmosphere. Then, 5 g of methanesulfonic acid was slowly added, and the mixture was stirred at a liquid temperature of 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. Then, the organic layer was dried under reduced pressure. 300 mL of THF was added to the residue, and the polymer was reprecipitated with 2000 mL of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain a comparative polymer (R3). When the weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, Mw = 2700 and Mw / Mn = 1.54.

[0175] Preparation of Resist Lower Layer Films (UDL-1 to 15, Comparative UDL-1 to 6) The above-mentioned compounds and polymers (D1) to (D12), (R1) to (R3), (X1) as a cross-linking agent, (BG1) to (BG3) as a base generator, and tripropylene glycol monomethyl ether (TPM) with a boiling point of 242 °C, 1,6-diacetoxyhexane (1,6-DAH) with a boiling point of 260 °C, and propylene glycol monomethyl ether acetate (PGMEA) containing 0.1% by mass of PF6320 (manufactured by OMNOVA) were dissolved at the ratios shown in Table 3, and then filtered through a 0.1-μm fluororesin filter to prepare resist underlayer film materials (UDL-1 to 15, Comparative UDL-1 to 6), respectively. [Chemical formula]

[0176] [Table 3]

[0177] Example 1: Film Formation Property Evaluation (Examples 1-1 to 1-15, Comparative Examples 1-1 to 1-6) The resist underlayer film materials (UDL-1 to 15, Comparative UDL-1 to 6) prepared above were coated on a Bare-Si substrate, a SiON-treated substrate, and a hexamethyldisilazane (HMDS)-treated substrate shown in Table 4, and baked at 250 °C for 60 seconds to form a resist underlayer film with a thickness of 100 nm. After formation, the organic film was observed using an optical microscope (ECLIPSE L200 manufactured by Nikon) to check for any coating abnormalities. The HMDS treatment was carried out under two conditions: 90 °C × 60 seconds and 120 °C × 120 seconds. As a result of measuring the water contact angle of each substrate using a contact angle meter (DM-701R manufactured by Kyowa Interface Science Co., Ltd.), the Bare-Si substrate was less than 15°, the SiON-treated substrate was 46°, the HMDS-treated (90 °C × 60 seconds) substrate was 58°, and the HMDS-treated (120 °C × 120 seconds) substrate was 66°. The HMDS treatment is a condition where it is difficult to ensure hydrophobicity and film-forming properties for substrates treated at high temperatures for a long time. Also, in this evaluation, the film thickness was made thin to evaluate the coating performance, resulting in severe evaluation conditions where film-forming abnormalities are likely to occur.

[0178]

Table 4

[0179] As shown in Table 4, the resist underlayer film material of the present invention was able to form a uniform resist underlayer film without coating abnormalities on the SiON-treated substrate and the HMDS-treated (90°C × 60 seconds) substrate. In Examples 1-1, 1-3, and 1-11 having no catechol-type terminal structure, slight pinholes occurred on the HMDS-treated (120°C × 120 seconds) substrate, but in other Examples having a catechol-type terminal structure, good film-forming properties were shown regardless of the substrate. Also, in Examples 1-1, 1-3, and 1-11, the film-forming property on the HMDS-treated (120°C × 120 seconds) substrate was improved compared with Comparative Examples 1-5 and 1-6, and the usefulness of combining a phenolic hydroxyl group-containing compound and a base generator could be confirmed. In Comparative Examples 1-1 and 1-2 where the base generator did not act during film baking, innumerable pinholes occurred on the HMDS-treated (120°C × 120 seconds) substrate, and the effect of improving the film-forming property was not confirmed. On the other hand, in Comparative Examples 1-3 and 1-4 containing a polymer, films could be formed on the SiON-treated substrate and the HMDS substrate regardless of the presence or absence of the base generator.

[0180] Example 2: Edge Retreating Property Evaluation (Examples 2-1 to 2-15, Comparative Examples 2-1 to 2-6) The resist underlayer film materials (UDL-1 to 15, Comparative UDL-1 to 6) prepared above were each applied onto a 12-inch Bare-Si substrate and a HMDS-treated (120°C × 120 seconds) substrate with an edge cut width of 2 mm, and baked at 250°C for 60 seconds to form a resist underlayer film with a film thickness of 100 nm (7 in Fig. 2(G)). The formed organic film was measured for film thickness using a film thickness measuring device (Atlas-XP manufactured by Onto Innovation Co., Ltd.) +Using [apparatus name], four measurements were taken for each substrate at 0.1 mm intervals in the range of 145 mm to 149 mm from the center 9 of the substrate (8 in Fig. 2(G)). Fig. 2(H) shows the average film thickness plot 10 on the Bare-Si substrate and the average film thickness plot 11 on the HMDS substrate. As shown here, the point where the average film thickness becomes 0 was defined as the film edge 12, and the difference in the film edge positions between the Bare-Si substrate and the HMDS-treated substrate was confirmed as the edge recession distance 13. The results are shown in Table 5. It is considered that the smaller the edge recession distance 13, the better the coatability on the HMDS substrate.

[0181]

Table 5

[0182] As shown in Table 5, in the examples having a catechol-type terminal structure, the edge recession distance of the resist underlayer film material of the present invention is generally 0.1 mm or less, and considering the error in film thickness measurement, it is considered that there is almost no recession of the film edge. In Examples 2-1, 2-3, and 2-11 that do not have a catechol-type terminal structure, the edge recession distance is 0.4 mm or less and there is a slight recession, but a clear improvement is recognized compared with Comparative Example 2-6, and the usefulness of combining a phenolic hydroxyl group-containing compound and a base generator can be confirmed. In Comparative Examples 2-1 and 2-2 where the base generator does not act during film baking, the recession of the film edge on the HMDS-treated substrate is very large and the film edge could not be confirmed within the measurement range. On the other hand, in Comparative Examples 2-3 and 2-4 containing a polymer, no recession of the film edge on the HMDS substrate occurred regardless of the presence or absence of the base generator.

[0183] Example 3: Embedding Property Evaluation (Examples 3-1 to 3-15, Comparative Examples 3-1 to 3-6) The resist underlayer film materials (UDL-1 to 15, Comparative UDL-1 to 6) prepared above were each applied onto a SiO2 wafer substrate having a dense hole pattern (hole diameter 0.16 μm, hole depth 0.50 μm, distance between the centers of two 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 14 (SiO2 wafer substrate) having a dense hole pattern as shown in FIGS. 3(I) (plan view) and (J) (cross-sectional view). The cross-sectional shape of each obtained wafer substrate was observed using a scanning electron microscope (SEM) to confirm whether the hole was filled with the resist underlayer film 15 without voids (gaps) inside the hole. The results are shown in Table 6. When a resist underlayer film material with poor embedding characteristics was used, voids occurred inside the holes in this evaluation. When a resist underlayer film material with good embedding characteristics was used, the hole was filled with the resist underlayer film without voids as shown in FIG. 3(K) in this evaluation.

[0184]

Table 6

[0185] As shown in Table 6, it was found that all of the resist underlayer film materials of the present invention were capable of filling the hole pattern without voids and had excellent embedding characteristics. On the other hand, in Comparative Examples 3-3 and 3-4, embedding defects were considered to occur due to insufficient thermal fluidity because they contained polymers.

[0186] Example 4: Planarization Property Evaluation (Examples 4-1 to 4-15, Comparative Examples 4-1 to 4-6) The resist underlayer film materials (UDL-1 to 15, Comparative UDL-1 to 6) prepared above were each applied onto a lower base substrate 16 (SiO2 wafer substrate) having a large isolated trench pattern (Figure 4(L), trench width 10 μm, trench depth 0.1 μm), baked at 250 °C for 60 seconds, and the step (delta 17 in Figure 4(M)) of the resist underlayer film 17 between the trench portion and the non-trench portion was observed using an NX10 atomic force microscope (AFM) manufactured by Park Systems. The results are shown in Table 7. In this evaluation, it can be said that the smaller the step, the better the planarization characteristics. Note that in this evaluation, a trench pattern with a depth of 0.10 μm was planarized using a resist underlayer film material with a film thickness of approximately 0.2 μm, and the evaluation conditions are strict in order to evaluate the superiority or inferiority of the planarization characteristics.

[0187]

Table 7

[0188] As shown in Table 7, it can be seen that the resist underlayer film material of the present invention has a smaller step between the trench portion and the non-trench portion of the resist underlayer film and is excellent in planarization characteristics compared to Comparative Examples 4-3 and 4-4 containing a polymer. Also, when comparing Example 4-10 with Comparative Example 4-5, or Example 4-11 with Comparative Example 4-6, it can be confirmed that there is no change in flatness and the addition of a base generator does not cause deterioration of flatness.

[0189] Example 5: Pattern Formation Test (Examples 5-1 to 5-10, Comparative Examples 5-1 to 5-6) The UDL-2, 6 to 10, 12 to 15 prepared above (Comparative Example UDL-1 to 6) were applied onto a SiO2 substrate having a trench pattern (trench width: 10 μm, trench depth: 0.10 μm) with a SiO2 film of 200 nm thickness formed by HMDS treatment (120 °C × 120 seconds), and baked at 250 °C for 60 seconds in the air on a Bare Si substrate to form a resist underlayer film so that the film thickness became 200 nm. A silicon-containing resist intermediate film material (SOG-1) was applied thereon and baked at 220 °C for 60 seconds to form a resist intermediate film with a film thickness of 35 nm. A resist upper layer film material (SL resist for ArF) was applied and baked at 105 °C for 60 seconds to form a resist upper layer film with a film thickness of 100 nm. A liquid immersion protective film (TC-1) was applied onto the resist upper layer film and baked at 90 °C for 60 seconds to form a protective film with a film thickness of 50 nm.

[0190] As the resist upper layer film material (SL resist for ArF), a polymer (RP1), an acid generator (PAG1), and a basic compound (Amine1) were dissolved in a solvent containing 0.1 mass% of FC-430 (manufactured by Sumitomo 3M Limited) at the ratios shown in Table 8, and filtered through a 0.1-μm fluororesin filter.

[0191]

Table 8

[0192] The structural formulas of the polymer (RP1), the acid generator (PAG1), and the basic compound (Amine1) used are shown below.

Chemical formula

[0193] As the liquid immersion protective film material (TC-1), a protective film polymer (PP1) was dissolved in an organic solvent at the ratios shown in Table 9, and filtered through a 0.1-μm fluororesin filter.

[0194]

Table 9

[0195] The structural formula of the polymer (PP1) used is shown below. [Chemical formula]

[0196] As the silicon-containing resist intermediate film material (SOG-1), a polymer represented by an ArF silicon-containing intermediate film polymer (SiP1) and a crosslinking catalyst (CAT1) were dissolved in an organic solvent containing 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M Limited) at the ratios shown in Table 10, and filtered through a fluororesin filter with a pore size of 0.1 μm to prepare the silicon-containing resist intermediate film material (SOG-1).

[0197] [Table 10]

[0198] The structural formulas of the ArF silicon-containing intermediate film polymer (SiP1) and the crosslinking catalyst (CAT1) used are shown below. [Chemical formula]

[0199] Next, exposure was performed while changing the exposure amount using an ArF immersion exposure apparatus (manufactured by Nikon Corporation; NSR-S610C, NA1.30, σ0.98 / 0.65, 35-degree dipole s-polarized illumination, 6% halftone phase shift mask), baking (PEB) was performed at 100 °C for 60 seconds, and development was performed for 30 seconds with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) to obtain a positive line-and-space pattern with a resist line width ranging from 50 nm to 30 nm at a pitch of 100 nm.

[0200] Next, using an etching apparatus Telius manufactured by Tokyo Electron, processing of the silicon-containing intermediate film was performed with the resist pattern by dry etching as a mask, processing of the lower layer film was performed with the silicon-containing intermediate film as a mask, and processing of the SiO2 film was performed with the lower layer film as a mask.

[0201] The etching conditions are as shown below. Transfer conditions of the resist pattern to the SOG film. Chamber pressure: 10.0 Pa RF power: 1,500 W CF4 gas flow rate: 15 sccm O2 gas flow rate: 75 sccm Time: 15 sec

[0202] Transfer conditions of the SOG film pattern to the underlying film. Chamber pressure: 2.0 Pa RF power: 500 W Ar gas flow rate: 75 sccm O2 gas flow rate: 45 sccm Time: 120 sec

[0203] Transfer conditions of the underlying film pattern to the SiO2 film. Chamber pressure: 2.0 Pa RF power: 2,200 W C5F 12 Gas flow rate: 20 sccm C2F6 gas flow rate: 10 sccm Ar gas flow rate: 300 sccm O2 gas flow rate: 60 sccm Time: 90 sec

[0204] The cross-section of the pattern was observed with an electron microscope (S-4700) manufactured by Hitachi, Ltd., and the shapes were compared and summarized in Table 11.

[0205]

Table 11

[0206] As shown in Table 11, as a result of the resist underlayer film materials (Examples 5-1 to 5-10) of the present invention, in all cases, the resist upper layer film pattern was finally successfully transferred to the substrate, and it was confirmed that the resist underlayer film materials of the present invention are suitably used for microfabrication by the multilayer resist method. On the other hand, in Comparative Examples 5-1, 5-2, 5-5, and 5-6, as shown by the results of the film-forming property evaluation of Example 1, during film formation pattern collapse occurred during pattern processing due to pinholes generated in the film, and patterns could not be formed. In Comparative Examples 5-3 and 5-4, as in Examples 3 and 4, since the embedding property and planarization property were inferior, pattern collapse occurred during pattern processing and patterns could not be formed.

[0207] From the above, the resist underlayer film material of the present invention has good film-forming properties and excellent embedding / planarization properties, so it is extremely useful as an organic film material used in the multilayer resist method. Also, in the pattern forming method of the present invention using this material, it has become clear that even if the object to be processed is a substrate having steps, fine patterns can be formed with high precision. Furthermore, the resist underlayer film material of the present invention does not need to contain an acid generator, can avoid problems such as pattern defects caused by decomposition products of the acid generator, and can maximize the effect of the base generator.

[0208] This specification includes the following aspects. [1]: A resist underlayer film material characterized by containing (A) a compound or resin containing a phenolic hydroxyl group, (B) a base generator, and (C) an organic solvent . [2]: The resist underlayer film material according to [1], wherein the polystyrene-reduced weight average molecular weight of the component (A) is 3,000 or less. [3]: The resist underlayer film material according to [1] or [2], wherein the base generator (B) is a compound that exhibits basicity by thermal decomposition. [4]: The resist underlayer film material according to any one of [1] to [3], characterized in that the (B) base generator is any one represented by the following general formulas (1), (2) and (3).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[10] : The resist underlayer film material according to any one of [7] to [9], wherein the general formula (9) is any one of the following general formulas (13) or (14).

Chemical formula

[11] : The resist underlayer film material according to any one of [7] to

[10] , wherein W in the general formula (7) is represented by the following general formula (15). [Chemical formula] (In the formula, the broken line represents a bond. R 15 is a hydrogen atom, or an alkyl group or an acyl group which may contain an oxygen atom or a nitrogen atom and has 1 to 20 carbon atoms. W 1 is an n-valent organic group having 1 to 47 carbon atoms. Y 1 is a single bond or a carbonyl group. n is an integer of 1 to 10.)

[12] : The resist underlayer film material according to

[11] , wherein W in the general formula (15) 1 has a structure represented by any of the following formulas. [Chemical formula] [Chemical formula] (In the formula, the broken line indicates a bond.)

[13] : The resist underlayer film material according to any one of [1] to

[12] , wherein the (C) organic solvent is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher.

[14] : The resist underlayer film material according to any one of [1] to

[13] , further containing one or more of (D) a surfactant, (E) a crosslinking agent, (F) a plasticizer, and (G) a pigment.

[15] : The resist underlayer film material according to

[14] , wherein the (E) crosslinking agent is a compound represented by the following general formula (16). [Chemical formula] (In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 16 is hydrogen or an alkyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5.)

[16] : A method for forming a pattern on a substrate to be processed, comprising (I-1) A step of forming a resist underlayer film by applying the resist underlayer film material according to any one of [1] to

[15] on a substrate to be processed and then performing heat treatment. (I-2) A step of forming a resist upper layer film on the resist underlayer film using a photoresist material. (I-3) A step of performing pattern exposure on the resist upper layer film and then developing it with a developer to form a 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 pattern is formed as a mask, and (I-5) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed. A pattern formation method characterized by comprising the above steps.

[17] : A method of forming a pattern on a substrate to be processed, (II-1) A step of forming a resist underlayer film by applying the resist underlayer film material according to any one of [1] to

[15] on a substrate to be processed and then performing heat treatment. (II-2) A step of forming a resist intermediate film on the resist underlayer film. (II-3) A step of forming a resist upper layer film on the resist intermediate film using a photoresist material. (II-4) A step of performing pattern exposure on the resist upper layer film and then developing it with a developer to form a pattern on the resist upper layer film. (II-5) A step of transferring the pattern to the resist intermediate film by dry etching using the resist upper layer film on which the pattern is formed as a mask. (II-6) A step of transferring the pattern to the resist underlayer film by dry etching using the resist intermediate film on which the pattern is transferred as a mask, and (II-7) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed. A pattern formation method characterized by comprising the above steps.

[18] : A method of forming a pattern on a substrate to be processed, (III-1) A step of forming a resist underlayer film by applying the resist underlayer film material according to any one of [1] to

[15] on a substrate to be processed and then performing heat treatment. (III-2) A step of forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film. (III-3) A step of forming an organic thin film on the inorganic hard mask intermediate film. (III-4) A step of forming a resist upper layer film on the organic thin film using a photoresist material. (III-5) A step of performing pattern exposure on the resist upper layer film and then developing it with a developer to form a pattern on the resist upper layer film. (III-6) A step of transferring the pattern to the organic thin film and the inorganic hard mask intermediate film by dry etching using the resist upper layer film on which the pattern is formed as a mask. (III-7) A step of transferring the pattern to the resist underlayer film by dry etching using the inorganic hard mask intermediate film on which the pattern is transferred as a mask, and (III-8) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed. A pattern forming method, characterized by comprising the above steps.

[19] : The pattern forming method according to

[18] , characterized in that the inorganic hard mask intermediate film is formed by a CVD method or an ALD method.

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

[16] to

[19] , characterized in that a substrate having a structure or step with a height of 30 nm or more is used as the substrate to be processed.

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

[16] to

[20] , characterized in that a substrate having a static contact angle with respect to water of 50° or more is used as the substrate to be processed.

[22] : A method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process, comprising spin-coating a resist underlayer film material described in any one of [1] to

[15] on a substrate to be processed, and curing the substrate coated with the resist underlayer film material by heat treatment at a temperature in the range of 100°C or higher and 600°C or lower for 10 to 600 seconds to form a resist underlayer film. A resist underlayer film forming method characterized by the above.

[23] : A method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process, comprising spin-coating a resist underlayer film material described in any one of [1] to

[15] on a substrate to be processed, and curing the substrate coated with the resist underlayer film material by heat treatment in an atmosphere with an oxygen concentration of 1% by volume or higher and 21% by volume or lower to form a resist underlayer film. A resist underlayer film forming method characterized by the above.

[24] : A method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process, comprising spin-coating a resist underlayer film material described in any one of [1] to

[15] on a substrate to be processed, and curing the substrate coated with the resist underlayer film material by heat treatment in an atmosphere with an oxygen concentration of less than 1% by volume to form a resist underlayer film. A resist underlayer film forming method characterized by the above.

[25] : The resist underlayer film forming method according to any one of

[22] to

[24] , characterized in that a substrate having a structure or step with a height of 30 nm or more is used as the substrate to be processed.

[26] : The resist underlayer film forming method according to any one of

[22] to

[25] , characterized in that a substrate having a static contact angle with respect to water of 50° or more is used as the substrate to be processed.

[0209] Note that the present invention is not limited to the above-described embodiments. The above-described embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Explanation of symbols

[0210] 1… Substrate, 2… Layer to be processed, 2a… Pattern formed on the layer to be processed, 3… Underlayer resist film, 3a… Underlayer resist film pattern, 4… Intermediate resist film, 4a… Intermediate resist film pattern, 5… Upperlayer resist film, 5a… Upperlayer resist film pattern, 6… Portion used (exposed portion), 7… Substrate coated with underlayer resist film, 8… Film thickness measurement positions (4 positions), 9… Center of the substrate, 10… Plot of average film thickness on Bare-Si substrate, 11… Plot of average film thickness on HMDS substrate, 12… Film edge, 13… Edge recession distance, 14… Substrate with dense hole pattern, 15… Underlayer resist film, 16… Substrate with large isolated trench pattern, 17… Underlayer resist film, delta 17… Step of underlayer resist film between trench portion and non-trench portion.

Claims

1. (A) A compound containing a phenolic hydroxyl group, (B) A base generator, and (C) An organic solvent which contains, and is characterized in that the compound (A) containing a phenolic hydroxyl group is represented by the following general formula (7). 【Chemical 1】 (In the formula, W is an n-valent organic group having 2 to 50 carbon atoms. Y is either a terminal group structure represented by the following general formula (8) or a terminal group structure represented by either of the following general formulas (13) or (14). When the proportions of the structures represented by the following general formula (8) and either of the structures represented by the following general formulas (13) or (14) constituting Y are a and b, respectively, a + b = 1.0, 0.70 ≤ a ≤ 0.99, and 0.01 ≤ b ≤ 0.

30. n is an integer from 1 to 10.) 【Chemical Formula 2】 (In the formula, the dashed line represents a bond. Z represents an (m + 1)-valent aromatic group having 6 to 20 carbon atoms. A is a single bond or -O-(CH₂)p-. m is an integer from 1 to 5. p is an integer from 1 to 10.) [Chemical Formula 3] (In the formula, the dashed line represents a bond.)

2. The resist lower layer film material according to claim 1, characterized in that the polystyrene-reduced weight average molecular weight of the component (A) is 3,000 or less.

3. The resist lower layer film material according to claim 1, characterized in that the base generator (B) is a compound that exhibits basicity upon thermal decomposition.

4. The resist lower layer film material according to claim 3, characterized in that the base generator (B) is any one of those represented by the following general formulas (1), (2), and (3). [Chemical Formula 4] (In the above formula, R ０１ ~R ０３ each independently represents a linear, branched or cyclic alkyl or alkenyl group having 1 to 10 carbon atoms which may be substituted with a heteroatom and may have a heteroatom intervening, or an aryl group or aralkyl group having 6 to 18 carbon atoms which may be substituted with a heteroatom and may have a heteroatom intervening. Also, any two of R ０１ , R ０２ and R ０３ may be bonded to each other to form a ring together with the sulfur atom in the formula. X － represents an organic or inorganic anion that serves as a counterion. However, X － does not contain OH － . R ０４ and R ０５ each independently represent an aryl group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms thereof may be substituted with a linear, branched or cyclic alkyl or alkoxy group having 1 to 10 carbon atoms. Also, R ０４ and R ０５ may be bonded to each other to form a ring together with the iodine atom in the formula. R ０６ , R ０７ , R ０８ and R ０９ each independently represent a hydrogen atom, or a linear, branched or cyclic alkyl or alkenyl group having 1 to 20 carbon atoms which may be substituted with a heteroatom and may have a heteroatom intervening, or an aryl group or aralkyl group having 6 to 18 carbon atoms which may be substituted with a heteroatom and may have a heteroatom intervening. Also, any two or more of R ０６ , R ０７ , R ０８ and R ０９ may be bonded to each other to form a ring together with the nitrogen atom in the formula.)

5. X in the general formulas (1), (2) and (3) above － is a structure represented by any of the following general formulas (4), (5) and (6), and an anion selected from the group consisting of chloride ion, bromide ion, iodide ion, fluoride ion, cyanide ion, nitrate ion, and nitrite ion. The resist underlayer film material according to claim 4, characterized in that. [Chemical Formula 5] (In the above formula, R １０ represents a linear, branched, or cyclic alkyl group, alkenyl group, aralkyl group, or aryl group having 1 to 20 carbon atoms which may contain an ether group, an ester group, or a carbonyl group, and one or more hydrogen atoms of these groups may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group, or a cyano group. R １１ represents an aryl group having 1 to 20 carbon atoms. One or more hydrogen atoms of the aryl group may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group, or a cyano group. R １２ , R １３ , R １４ each independently represents a hydrogen atom, a halogen atom other than fluorine, or a linear, branched, or cyclic alkyl group, alkenyl group, aralkyl group, or aryl group having 1 to 20 carbon atoms which may contain an ether group, an ester group, or a carbonyl group, and one or more hydrogen atoms of these groups may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group, or a cyano group. Further, two or more of R １２ , R １３ , R １４ may be bonded to each other to form a ring.)

6. X in the general formulas (1), (2) and (3) above － The resist underlayer film material according to claim 4, characterized in that the boiling point of the conjugate acid X-H of is 200°C or lower.

7. A in the general formula (8) is -OCH ２ - The resist underlayer film material according to claim 1, characterized in that it is so.

8. The resist lower layer film material according to claim 1, characterized in that the general formula (8) is any one of the following general formulas (10), (11), and (12). 【Chemical Formula 6】 (In the formula, the dashed line represents a bond.)

9. The resist lower layer film material according to claim 1, characterized in that W in the general formula (7) is represented by the following general formula (15). [Chemical Formula 7] (In the formula, the broken line represents a bond. R １５ is a hydrogen atom, or an alkyl group or an acyl group which may contain an oxygen atom or a nitrogen atom and has 1 to 20 carbon atoms. W １ is an n-valent organic group having 1 to 47 carbon atoms. Y １ is a single bond or a carbonyl group. n is an integer of 1 to 10.)

10. W in the general formula (15) above １ The resist underlayer film material according to claim 9, wherein W has a structure represented by any of the following formulas. 【Chemical Formula 8】 【Chemical Formula 9】 (In the formula, the dashed line indicates a bond.)

11. The resist lower layer film material according to claim 1, characterized in that the organic solvent (C) is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher.

12. The resist lower layer film material according to claim 1, further containing one or more of (D) a surfactant, (E) a crosslinking agent, (F) a plasticizer, and (G) a pigment.

13. The resist underlayer film material according to claim 12, wherein the (E) crosslinking agent is a compound represented by the following general formula (16). 【Chemical Formula 10】 (In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R １６ is hydrogen or an alkyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5.)

14. A method of forming a pattern on a substrate to be processed, comprising: (I-1) A step of forming a resist underlayer film by applying the resist underlayer film material according to any one of claims 1 to 13 on the substrate to be processed and then performing a heat treatment. (I-2) A step of forming a resist upper layer film on the resist underlayer film using a photoresist material. (I-3) A step of forming a pattern on the resist upper layer film by subjecting the resist upper layer film to pattern exposure and then developing it with a developer. (I-4) A step of transferring the pattern to the resist underlayer film by dry etching using the resist upper layer film having the pattern as a mask, and (I-5) A step of processing the substrate to be processed using the resist underlayer film having the pattern as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by comprising the above steps.

15. A method of forming a pattern on a substrate to be processed, comprising: (II-1) A step of forming a resist underlayer film by applying the resist underlayer film material according to any one of claims 1 to 13 on the substrate to be processed and then performing a heat treatment. (II-2) A step of forming a resist intermediate film on the resist underlayer film. (II-3) A step of forming a resist upper layer film on the resist intermediate film using a photoresist material. (II-4) A step of forming a pattern on the resist upper layer film by subjecting the resist upper layer film to pattern exposure and then developing it with a developer. (II-5) A step of transferring the pattern to the resist intermediate film by dry etching using the resist upper layer film having the pattern as a mask. (II-6) A step of transferring the pattern to the resist underlayer film by dry etching using the resist intermediate film having the pattern transferred thereto as a mask, and (II-7) A step of processing the substrate to be processed using the resist underlayer film having the pattern as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by comprising the above steps.

16. A method of forming a pattern on a substrate to be processed, comprising: (III-1) A step of forming a resist underlayer film by applying the resist underlayer film material according to any one of claims 1 to 13 on the substrate to be processed and then performing a heat treatment. (III-2) A step of forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist lower layer film; (III-3) A step of forming an organic thin film on the inorganic hard mask intermediate film; (III-4) A step of forming a resist upper layer film on the organic thin film using a photoresist material; (III-5) After pattern exposure of the resist upper layer film, developing with a developer to form a pattern in the resist upper layer film; (III-6) A step of transferring the pattern to the organic thin film and the inorganic hard mask intermediate film by dry etching using the resist upper layer film having the pattern as a mask; (III-7) A step of transferring the pattern to the resist lower layer film by dry etching using the inorganic hard mask intermediate film having the pattern transferred as a mask, and (III-8) A step of processing the substrate to be processed using the resist lower layer film having the pattern formed as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by comprising the above steps.

17. The pattern forming method according to claim 16, wherein the inorganic hard mask intermediate film is formed by a CVD method or an ALD method.

18. The pattern forming method according to claim 14, wherein a substrate having a structure or step with a height of 30 nm or more is used as the substrate to be processed.

19. The pattern forming method according to claim 14, wherein a substrate having a static contact angle with respect to water of 50° or more is used as the substrate to be processed.

20. A method for forming a resist lower layer film that functions as an organic planarizing film in a semiconductor device manufacturing process, wherein the resist lower layer film material according to any one of claims 1 to 13 is spin-coated on a substrate to be processed, and the substrate coated with the resist lower layer film material is heat-treated at a temperature in the range of 100°C or more and 600°C or less for 10 to 600 seconds to be cured to form a resist lower layer film.

21. A method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process, comprising spin-coating a resist underlayer film material according to any one of claims 1 to 13 on a substrate to be processed, and heat-treating the substrate coated with the resist underlayer film material in an atmosphere having an oxygen concentration of 1% by volume or more and 21% by volume or less to cure and form a resist underlayer film.

22. A method for forming a resist underlayer film that functions as an organic planarizing film used in a semiconductor device manufacturing process, comprising spin-coating a resist underlayer film material according to any one of claims 1 to 13 on a substrate to be processed, and heat-treating the substrate coated with the resist underlayer film material in an atmosphere having an oxygen concentration of less than 1% by volume to cure and form a resist underlayer film.

23. The method for forming a resist underlayer film according to claim 20, wherein a substrate having a structure or step with a height of 30 nm or more is used as the substrate to be processed.

24. The method for forming a resist underlayer film according to claim 20, wherein a substrate having a static contact angle with respect to water of 50° or more is used as the substrate to be processed.

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