Composition for forming resist underlayer film and patterning process

Abstract

To provide a composition for forming a resist underlayer film having an excellent filling property and adhesiveness to a substrate, and a patterning formation method using the same.SOLUTION: A composition for forming a resist underlayer film, applied for a multilayer resist method, contains (A) a resin, (B) a base generator, and (C) an organic solvent, wherein weight-average molecular weight of (A) the resin is 3,000 to 10,000, (A) the resin is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying a phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying a phenolic hydroxyl group, and (A) the resin satisfies relations of a+b=1, 0.1≤a≤0.5, and 0.5≤b≤0.9, wherein "a" is a proportion of a phenolic hydroxyl group and "b" is a proportion of a group obtained by modifying a phenolic hydroxyl group contained in (A) the resin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a composition for forming a resist underlayer film and a method for forming a pattern. [Background technology]

[0002] As LSIs become more highly integrated and faster, pattern dimensions are becoming finer. Lithography technology has achieved the formation of finer patterns by shortening the wavelength of light sources and selecting appropriate resist compositions to match them, in line with this trend. The core of this technology is a positive photoresist composition used in a single layer. This single-layer positive photoresist composition has a skeleton in the resist resin that is resistant to dry etching using chlorine- or fluorine-based gas plasma, and also has a switching mechanism that dissolves the exposed areas, forming a pattern by dissolving the exposed areas, and then dry etching the substrate using the remaining resist pattern as an etching mask.

[0003] However, when the thickness of the photoresist film used is made finer, that is, when the pattern width is made smaller, the resolution performance of the photoresist film is reduced, and when an attempt is made to develop the photoresist film into a pattern using a developer, the so-called aspect ratio becomes too large, resulting in problems such as pattern collapse. For this reason, photoresist films have been made thinner as patterns become finer.

[0004] On the other hand, in processing a substrate to be processed, a method is usually used in which a photoresist film on which a pattern is formed is used as an etching mask to process the substrate by dry etching, but in reality, there is no dry etching method that can obtain perfect etching selectivity between the photoresist film and the substrate to be processed. Therefore, there is a problem that the resist film is also damaged and collapsed during processing of the substrate, and the resist pattern cannot be accurately transferred to the substrate to be processed. Therefore, with the miniaturization of patterns, a higher dry etching resistance has been required for the resist composition. However, on the other hand, in order to increase the resolution, a resin with low light absorption at the exposure wavelength has been required for the resin used in the photoresist composition. Therefore, as the exposure light has become shorter in wavelength from i-line to KrF and ArF, the resin has also changed to novolac resin, polyhydroxystyrene, and resin with an aliphatic polycyclic skeleton, but in reality, the etching speed under dry etching conditions during substrate processing has become faster, and recent photoresist compositions with high resolution tend to have weaker etching resistance.

[0005] For this reason, it has become necessary to dry etch the substrate to be processed using a thinner photoresist film with a weaker etching resistance, and securing the materials and processes for this processing step has become an urgent need.

[0006] One method for solving such problems is the multi-layer resist method, in which a resist underlayer film having etching selectivity different from that of a photoresist film (i.e., a resist upper layer film) is interposed between the resist upper layer film and a substrate to be processed, a pattern is obtained in the resist upper layer film, and then the pattern is transferred to the resist underlayer film by dry etching using the resist upper layer film pattern as a dry etching mask, and the pattern is further transferred to the substrate to be processed by dry etching using the resist underlayer film as a dry etching mask.

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

[0008] On the other hand, in recent years, 3D-NAND memory, which makes memory three-dimensional, is becoming mainstream, and the manufacturing of this 3D-NAND memory requires the formation of a thick resist underlayer film in a single process in the multi-layer resist method. Therefore, it is necessary to make the resin concentration in the resist underlayer film material a high value of 10 mass% or more. In addition, the high stacking of 3D-NAND memory has been active recently, and in response to this, the resist underlayer film is required to have better performance than ever before in terms of the gap-filling property of filling the pattern with a film without voids.

[0009] As a resist underlayer film material capable of forming a thick resist underlayer film, for example, Patent Document 2 proposes a material containing a crosslinking agent in an olefin polymer or a novolac polymer. However, with the above material, there is a concern that voids may occur due to the large amount of hydroxyl groups contained in the polymer structure, which reduces fluidity when embedding in a substrate having deep patterns used in cutting-edge processes.

[0010] On the other hand, as a resist underlayer film material containing a compound having a structure in which a hydroxyl group contained in a polymer is protected, a material in which a hydroxyl group contained in a novolac polymer is protected with a group containing a triple bond is known (Patent Document 3). However, the above material has insufficient adhesion to the substrate to be processed, and there is a concern that defects such as peeling may occur during processing.

[0011] As described above, in the manufacture of 3D-NAND memories, which are becoming increasingly highly stacked, there is a demand for a resist underlayer film material for use in manufacturing semiconductor devices that has good filling characteristics without the occurrence of defects such as voids or peeling, and a pattern formation method using the same. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2004-205685 A [Patent Document 2] Patent No. 6550760 [Patent Document 3] Patent No. 5821694 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a composition for forming a resist underlayer film having excellent embedding properties and substrate adhesion, and a pattern forming method using the same. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides a composition for forming a resist underlayer film used in a multi-layer resist method, the composition comprising (A) a resin, (B) a base generator, and (C) an organic solvent, The weight average molecular weight of the (A) resin is 3,000 to 10,000, the (A) resin is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying the phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying the phenolic hydroxyl group, The present invention provides a composition for forming a resist underlayer film, which satisfies the relationships a+b=1, 0.1≦a≦0.5, and 0.5≦b≦0.9, where a is the proportion of phenolic hydroxyl groups contained in the (A) resin, and b is the proportion of groups modified with the phenolic hydroxyl groups.

[0015] A composition for forming a resist underlayer film containing such a structure can have excellent filling properties and substrate adhesion, and by adjusting the proportion of the structure within the above range, it is possible to both eliminate voids and suppress substrate peeling when filling the substrate to be processed.

[0016] In the present invention, the (A) resin preferably contains any one of a styrene unit, a novolac type phenol unit, and a novolac type naphthol unit.

[0017] By containing such a resin, it is possible to provide a composition for forming a resist underlayer film that has excellent filling properties and etching resistance.

[0018] In the present invention, the (A) resin is preferably a resin having a structural unit represented by the following general formula (1-1) or the following general formula (1-2). [ka] (In the general formula (1-1), R 00 is a hydrogen atom or a methyl group, and R 01is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R 02 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, 02 In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationships a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 are satisfied. m1 is an integer of 0 to 4, n1 is an integer of 1 to 5, and m1+n1 is an integer of 1 or more and 5 or less. [ka] (In the general formula (1-2), R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R 02 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, 02 In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationships a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 are satisfied. X is a divalent organic group having 1 to 30 carbon atoms, p is 0 or 1, and when p is 0, m2 is an integer of 0 to 3, n2 is an integer of 1 to 4, and m2+n2 is an integer of 1 or more and 4 or less, and when p is 1, m2 is an integer of 0 to 5, n2 is an integer of 1 to 6, and m2+n2 is an integer of 1 or more and 6 or less.)

[0019] A composition for forming a resist underlayer film containing such a resin can achieve a high degree of both embedding properties and substrate adhesion, and can form a thick resist underlayer film without causing film formation defects such as cracks.

[0020] In the present invention, in the general formulas (1-1) and (1-2), 02 is preferably any one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a structure represented by the following general formula (8). [ka] (In the general formula (8), * represents a bonding site to an oxygen atom, and R Arepresents an optionally substituted divalent organic group having 1 to 10 carbon atoms; R B is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms.

[0021] A composition for forming a resist underlayer film containing such a resin can further improve the embedding properties.

[0022] In the present invention, it is preferable that p is 0 in the general formula (1-2).

[0023] In the present invention, it is preferable that n1 is 1 in the general formula (1-1).

[0024] In the present invention, n2 is preferably 1 in the general formula (1-2).

[0025] A composition for forming a resist underlayer film containing such a resin can further improve the filling properties.

[0026] In the present invention, it is preferable that a and b satisfy the relationships a+b=1, 0.15≦a≦0.4, and 0.6≦b≦0.85.

[0027] A composition for forming a resist underlayer film containing such a resin can achieve both excellent embedding properties and excellent substrate adhesion to a higher degree.

[0028] In the present invention, the (B) base generator is preferably a compound that develops basicity through thermal decomposition.

[0029] It is expected that such a composition for forming a resist underlayer film will have excellent film-forming properties because the phenolic hydroxyl groups contained in the resin (A) will have ionic properties during film baking, increasing the interaction with the substrate. By adjusting the content of the phenolic hydroxyl groups in the resin (A) and the amount of the base generator (B) added, it is possible to achieve both embedding properties and substrate adhesion.

[0030] Furthermore, the base generator (B) is preferably any one of those represented by the following general formulas (2), (3) and (4). [ka] (In the above formula, R 01 ~R 03 each independently represents a linear, branched or cyclic alkyl group, alkenyl group or aralkyl group having 1 to 10 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. 01 , R 02 and R 03 Any two of X may be bonded to each other to form a ring together with the sulfur atom in the formula. - represents an organic or inorganic counterion. - OH - Does not include R 04 and R 05 are each independently an aryl group having 6 to 20 carbon atoms which may be substituted or interposed with a heteroatom, and some or all of the hydrogen atoms in the aryl group may be substituted with a linear, branched or cyclic alkyl or alkoxy group having 1 to 10 carbon atoms. 04 and R 05 may be bonded to each other to form a ring together with the iodine atom in the formula. 06 , R 07 , R 08 and R 09 each independently represents a hydrogen atom, or a linear, branched or cyclic alkyl group or alkenyl group having 1 to 20 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aralkyl group having 7 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. 06 , R 07 , R 08 and R 09 Any two or more of may be bonded to each other to form a ring together with the nitrogen atom in the formula.

[0031] Furthermore, X in the general formulas (2), (3) and (4) - is more preferably any one of a structure represented by any one of the following general formulas (5), (6), and (7), and an anion selected from the group consisting of a chloride ion, a bromide ion, an iodide ion, a fluoride ion, a cyanide ion, a nitrate ion, and a nitrite ion. [ka] (In the above formula, R 10 R represents an ether group, an ester group, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, 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. 11 R represents an aryl group having 6 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. 12 , R 13 , R 14 each independently represents a hydrogen atom, a halogen atom other than a fluorine atom, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain an ether group, an ester group or a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, in which one or more hydrogen atoms may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. 12 , R 13 , R 14 Two or more of may be bonded to each other to form a ring.)

[0032] By appropriately selecting such a base generator (thermal base generator) that exhibits basicity by thermal decomposition, it is possible to exhibit basicity in accordance with the baking temperature of the composition for forming a resist underlayer film, and it is possible to achieve both embedding properties and substrate adhesion. In addition, since the entire amount is decomposed or evaporated during baking and does not remain in the film after baking, there is no adverse effect on performance other than film formability.

[0033] The ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn of the (A) resin, as calculated using polystyrene standards by gel permeation chromatography, is preferably 2.00≦Mw / Mn≦5.00.

[0034] A composition for forming a resist underlayer film containing such a resin can suppress the generation of sublimates during film baking, so that a resist underlayer film having excellent film thickness uniformity and defect suppression can be formed. In addition, the composition has excellent thermal fluidity, so that the embedding property can be further improved.

[0035] In the present invention, the content of the resin (A) in the composition for forming a resist underlayer film is preferably 20% by mass or more.

[0036] If the concentration of the (A) resin contained in the composition for forming a resist underlayer film is within the above range, a resist underlayer film with a large thickness can be formed by one coating, which is preferable from the viewpoint of device productivity.

[0037] In the present invention, the composition for forming a resist underlayer film may contain (D) a crosslinking agent.

[0038] By including the crosslinking agent (D) in the composition for forming the resist underlayer film, the curing properties can be improved, which is advantageous in thermally curing a thick resist underlayer film.

[0039] In addition, in the present invention, the composition for forming a resist underlayer film can contain (E) a flowability promoter that has a weight loss rate of less than 30% from 30°C to 190°C and a weight loss rate of 98% or more from 30°C to 350°C.

[0040] The (E) flowability promoter preferably contains one or more compounds selected from the following general formulas (i) to (iii). [ka] (In the formula, R 1 are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms. 1 W is a phenylene group or a divalent group represented by the following general formula (i-1). 2 , W 3 is a single bond or a divalent group represented by the following general formula (i-2): 1 is an integer from 1 to 10, and n 1 is an integer between 0 and 5.) [ka] (In the formula, * indicates a bond position, and R 10 , R 11 , R 12 , R 13 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. 10 , W 11 Each of m is independently a single bond or a carbonyl group. 10 , m 11 is an integer from 0 to 10, and m 10 +m 11 ≧1.) [ka] (In the formula, * indicates the bond position.) [ka] (In the formula, R 2are each independently a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms. 4 W is a divalent group represented by the following general formula (ii-1). 5 is a single bond or a divalent group represented by the following general formula (ii-2): 2 is an integer from 2 to 10, and n 3 is an integer between 0 and 5.) [ka] (In the formula, * indicates a bond position, and R 20 , R 21 , R 22 , R 23 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. 20 , m 21 is an integer from 0 to 10, and m 20 +m 21 ≧1.) [ka] (In the formula, * indicates the bond position.) [ka] (In the formula, R 3 , R 4 R is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and may be bonded to each other to form a cyclic structure. 5 , R 6 is an organic group having 1 to 10 carbon atoms, R 5 is a group containing either an aromatic ring or a divalent group represented by the following general formula (iii-1): 6 , W 7 is a single bond or a divalent group represented by the following general formula (iii-2), and at least one of them is a divalent group represented by (iii-2). [ka] (In the formula, * indicates a bond position, and W 30 is an organic group having 1 to 4 carbon atoms. [ka] (In the formula, * indicates the bond position.)

[0041] By including such a flow promoter (E), the thermal flow property of the resin (A) is promoted, and therefore the embedding characteristics can be further improved.

[0042] In the present invention, the composition for forming a resist underlayer film may further contain one or more of (F) a surfactant and (G) a plasticizer.

[0043] In the composition for forming a resist underlayer film of the present invention, depending on the necessity, the presence or absence / selection of the above-mentioned additives enables fine adjustment of performance according to requirements, such as coating film formability by spin coating, curing temperature, embedding / planarization characteristics, and optical characteristics (light absorption characteristics), which is preferable from a practical standpoint.

[0044] The present invention also provides a method for forming a pattern on a workpiece substrate, comprising the steps of: (I-1) a step of applying the composition for forming a resist underlayer film of the present invention onto a substrate to be processed, and then heat-treating the composition to form a resist underlayer film; (I-2) 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-exposing the resist upper layer film and then developing the resist upper layer film 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 pattern has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0045] The present invention also provides a method for forming a pattern on a workpiece substrate, comprising the steps of: (II-1) a step of applying the composition for forming a resist underlayer film of the present invention onto a substrate to be processed, and then heat-treating the composition to form a resist underlayer film; (II-2) forming a resist intermediate film on the resist underlayer film; (II-3) 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 pattern-exposing the resist upper layer film and then developing the resist upper layer film 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 on which the pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the resist intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0046] The present invention also provides a method for forming a pattern on a workpiece substrate, comprising the steps of: (III-1) a step of applying the composition for forming a resist underlayer film of the present invention onto a substrate to be processed, and then heat-treating the composition to form a resist underlayer 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 underlayer film; (III-3) forming an organic thin film on the inorganic hard mask intermediate film; (III-4) forming a resist top layer film on the organic thin film using a photoresist material; (III-5) a step of forming a pattern on the resist upper layer film by pattern-exposing the resist upper layer film and then developing the resist upper layer film with a developer; (III-6) a step of transferring a 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 has been formed as a mask; (III-7) a step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0047] In this way, the composition for forming a resist underlayer film 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 silicon-containing resist intermediate film, and in addition to these, a four-layer resist process using an organic thin film. In these pattern formation methods, the formation of a resist underlayer film can effectively reduce unevenness and steps on the processed substrate, and is suitable for photolithography of a resist upper layer film.

[0048] In the above-mentioned pattern formation method, the resist underlayer film preferably has a thickness of at least 2 μm.

[0049] In the above-mentioned pattern forming method, the method for forming the resist underlayer film preferably comprises applying the composition for forming a resist underlayer film of the present invention once to a thickness of at least 2 μm.

[0050] Such a pattern formation method is preferable from the viewpoint of device productivity since it is possible to form a thick resist underlayer film by a single coating. Effect of the Invention

[0051] As described above, the resist underlayer film forming composition and the pattern forming method of the present invention are particularly suitable for use in a multilayer resist process, including filling / flattening a substrate to be processed having steps and irregularities, and are extremely useful in fine patterning for manufacturing semiconductor devices. In particular, in a fine patterning process using a multilayer resist method in a semiconductor device manufacturing process, a resist underlayer film can be formed with excellent filling characteristics without causing defects such as voids or peeling, even on a substrate to be processed having a large aspect ratio and particularly difficult to fill, such as a 3D-NAND memory that is becoming increasingly highly stacked, and further has suitable flattening characteristics, etching characteristics, and optical characteristics, and a pattern forming method using the composition can be provided. [Brief description of the drawings]

[0052] [Figure 1] FIG. 1 is an explanatory diagram of an example of the pattern forming method of the present invention (three-layer resist process). [Diagram 2] FIG. 2 is an explanatory diagram of a method for evaluating embedding characteristics. [Diagram 3] FIG. 3 is a set of SEM images showing the cross-sectional shapes of a resist underlayer film and a substrate formed using a composition of the present invention and a resist underlayer film and a substrate formed using a comparative composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] As described above, in a fine patterning process using a multilayer resist method in a semiconductor device manufacturing process, there has been a demand for a composition for forming a resist underlayer film and a pattern forming method that can form a resist underlayer film with excellent filling characteristics and without defects such as voids or peeling, even on a substrate to be processed that has a large aspect ratio and is particularly difficult to fill, such as a 3D-NAND memory that is becoming increasingly highly stacked.

[0054] The present inventors have been searching for various resist underlayer film materials and pattern formation methods in order to realize high-level embedding on a substrate to be processed having a portion with a large aspect ratio, such as that of a 3D-NAND memory, which is particularly difficult to embed, and to simultaneously achieve adhesion to the substrate to be processed when a thick resist underlayer film is formed, in multilayer lithography using a resist underlayer film. As a result, the inventors have found that a composition for forming a resist underlayer film, which contains a resin having a specific structure and a base generator, and a pattern formation method are very effective, and have completed the present invention.

[0055] That is, the present invention relates to a composition for forming a resist underlayer film used in a multi-layer resist method, the composition comprising (A) a resin, (B) a base generator, and (C) an organic solvent, The weight average molecular weight of the (A) resin is 3,000 to 10,000, the (A) resin is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying the phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying the phenolic hydroxyl group, The composition for forming a resist underlayer film is characterized in that, when the ratio of phenolic hydroxyl groups contained in the (A) resin is a and the ratio of groups to which the phenolic hydroxyl groups have been modified is b, the composition satisfies the relationships a+b=1, 0.1≦a≦0.5, and 0.5≦b≦0.9.

[0056] The present invention will be described in detail below, but the present invention is not limited thereto.

[0057] [Composition for forming resist underlayer film] The composition for forming a resist underlayer film of the present invention is a composition for forming a resist underlayer film used in a multilayer resist method as described above, and contains (A) a resin, (B) a base generator, and (C) an organic solvent, The weight average molecular weight of the (A) resin is 3,000 to 10,000, the (A) resin is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying the phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying the phenolic hydroxyl group, The composition for forming a resist underlayer film is characterized in that, when the ratio of phenolic hydroxyl groups contained in the (A) resin is a and the ratio of groups to which the phenolic hydroxyl groups have been modified is b, the composition satisfies the relationships a+b=1, 0.1≦a≦0.5, and 0.5≦b≦0.9.

[0058] The (A) resin contains groups modified with phenolic hydroxyl groups in the above-mentioned range, which gives the composition for forming a resist underlayer film excellent thermal fluidity, and therefore a resist underlayer film with excellent embedding properties can be formed. Also, the (A) resin contains phenolic hydroxyl groups in the above-mentioned range, which acts with the (B) base generator to form a resist underlayer film with excellent substrate adhesion.

[0059] Furthermore, the composition for forming a resist underlayer film of the present invention contains (A) a resin, (B) a base generator, and (C) an organic solvent, and the content of (A) the resin is preferably 20 mass % or more, more preferably 25 mass % or more, and even more preferably 30 mass % or more.

[0060] When the composition for forming a resist underlayer film contains the resin (A) in the above-mentioned ratio, a thick resist underlayer film can be formed by a single coating.

[0061] [(A) Resin] The (A) resin contained in the composition for forming a resist underlayer film of the present invention is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying the phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying the phenolic hydroxyl group, When the ratio of phenolic hydroxyl groups contained in the resin is a and the ratio of groups modified with phenolic hydroxyl groups is b, the relationship of a+b=1, 0.1≦a≦0.5, 0.5≦b≦0.9 is satisfied. The relationship between a and b is preferably a+b=1, 0.1≦a≦0.5, 0.5≦b<0.9, and more preferably a+b=1, 0.15≦a≦0.4, 0.6≦b≦0.85. When the ratio of b is less than 0.5, the contribution of hydrogen bonds of phenolic hydroxyl groups becomes large, and the complex viscosity of the resin increases, so that there is a concern that the resin shows lower fluidity and the embedding characteristics are deteriorated. When the ratio of b is more than 0.9, the ratio of phenolic hydroxyl groups in the resin becomes low, and the action with the base generator (B) becomes weak, so that there is a concern that the adhesion to the substrate to be processed is deteriorated. The (A) resin preferably contains any one of a styrene unit, a novolac type phenol unit, and a novolac type naphthol unit.

[0062] In particular, a resin having a structural unit represented by the following general formula (1-1) or the following general formula (1-2) is preferred. [ka] (In the general formula (1-1), R 00 is a hydrogen atom or a methyl group, and R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R 02 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, 02 In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationships a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 are satisfied. m1 is an integer of 0 to 4, n1 is an integer of 1 to 5, and m1+n1 is an integer of 1 or more and 5 or less. [ka] (In the general formula (1-2), R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R 02is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, 02 In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationships a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 are satisfied. X is a divalent organic group having 1 to 30 carbon atoms, p is 0 or 1, and when p is 0, m2 is an integer of 0 to 3, n2 is an integer of 1 to 4, and m2+n2 is an integer of 1 or more and 4 or less, and when p is 1, m2 is an integer of 0 to 5, n2 is an integer of 1 to 6, and m2+n2 is an integer of 1 or more and 6 or less.)

[0063] The (A) resin is a resin having a structural unit represented by general formula (1-1) or general formula (1-2), so that a composition for forming a resist underlayer film having excellent thermal fluidity and substrate affinity can be provided. In addition, a thick resist underlayer film having excellent etching resistance can be formed without causing film formation defects such as cracks.

[0064] In the above general formulas (1-1) and (1-2), R 01 Examples of the optionally substituted saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms and represented by the formula (I) include monovalent saturated hydrocarbon groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, and a tert-pentyl group; and monovalent unsaturated chain hydrocarbon groups such as an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, an ethynyl group, and a propynyl group. monovalent monocyclic unsaturated cyclic hydrocarbon groups such as a cyclobutenyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, or a cyclooctyl group; monovalent polycyclic cyclic hydrocarbon groups such as a norbornyl group or an adamantyl group; and monovalent aromatic hydrocarbon groups such as a phenyl group, a methylphenyl group, a naphthyl group, a methylnaphthyl group, an anthryl group, or a methylanthryl group.

[0065] Above R 01Examples of the organic group represented by the formula (I) include alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, and an n-hexyloxy group; and alkoxycarbonyl groups such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, an i-butoxycarbonyl group, a sec-butoxycarbonyl group, a t-butoxycarbonyl group, an n-pentyloxycarbonyl group, and an n-hexyloxycarbonyl group.

[0066]

[0043] Some or all of the hydrogen atoms in the above-mentioned saturated hydrocarbon groups, unsaturated chain hydrocarbon groups, monocyclic saturated cyclic hydrocarbon groups, monocyclic unsaturated cyclic hydrocarbon groups, polycyclic cyclic hydrocarbon groups, aromatic hydrocarbon groups, alkoxy groups, alkoxycarbonyl groups and the like may be substituted, and examples of the substituent include halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxyl group, a cyano group, a carboxy group, a nitro group, an amino group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an alkoxycarbonyloxy group, an aryl group, an aliphatic heterocyclic group such as a lactone group, and an aromatic heterocyclic group such as a furyl group or a pyridyl group.

[0067] From the viewpoint of embedding characteristics and raw material availability, 01 The organic group represented by the formula (I) is preferably a methyl group.

[0068] In the above general formula (1-2), examples of the divalent organic group having 1 to 30 carbon atoms represented by X include alkanediyl groups such as methylene group, ethanediyl group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, octanediyl group, and decanediyl group; monocyclic cycloalkanediyl groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group, cycloheptanediyl group, cyclooctanediyl group, cyclodecanediyl group, methylcyclohexanediyl group, and ethylcyclohexanediyl group; bicyclo[2.2.1]heptanediyl group, bicyclo[2.2.2]octanediyl group, tricyclo[5.2.1.0]diyl group, and the like. 2,6 ]Decanediyl group (dicyclopentylene group), tricyclo[3.3.1.1 3,7 ]decanediyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Polycyclic cycloalkanediyl groups such as dodecanediyl group and adamantanediyl group; arenediyl groups such as phenylene group and naphthylene group.

[0069] Examples of the alkanediyloxy group represented by X include groups in which the alkanediyl group and an oxygen atom are combined, and examples of the cycloalkanediyloxy group represented by X include groups in which the cycloalkanediyl group and an oxygen atom are combined.

[0070] A part or all of the hydrogen atoms of the alkanediyl group, cycloalkanediyl group, alkanediyloxy group, cycloalkanediyloxy group, and arenediyl group may be substituted. Examples of the substituent include the above-mentioned R 01 The examples of the substituent that may be possessed by the organic group represented by the following formula include the same groups as those mentioned above.

[0071] Examples of the organic group represented by X include groups represented by the following formulas. [ka] (In the above formula, * represents a bond.)

[0072] From the viewpoints of embedding properties and availability of raw materials, the organic group represented by X is preferably a methylene group.

[0073] In the above general formulas (1-1) and (1-2), R 02 is a hydrogen atom or an optionally substituted saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, R 02 Preferred examples of the structure include a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and any of the structures represented by the following general formula (8). [ka] (In the above general formula (8), * represents a bonding site to an oxygen atom, and R A is a divalent organic group having 1 to 10 carbon atoms which may be substituted; R B is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms.

[0074] In the above general formula (8), R A Examples of the divalent organic group having 1 to 10 carbon atoms represented by the formula (1) include alkanediyl groups such as a methylene group, an ethanediyl group, a propanediyl group, a butanediyl group, a pentanediyl group, a hexanediyl group, an octanediyl group, and a decanediyl group, and arenediyl groups such as a benzenediyl group, a methylbenzenediyl group, and a naphthalenediyl group.

[0075] In the above general formula (8), R B Examples of the monovalent organic group having 1 to 10 carbon atoms represented by the formula (1) include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, and an n-decyl group, and aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group.

[0076] A part or all of the hydrogen atoms of the alkanediyl group, arenediyl group, alkyl group, aryl group, etc. may be substituted. Examples of the substituent include the above-mentioned R01 The examples of the substituent that may be possessed by the organic group represented by the following formula include the same groups as those mentioned above.

[0077] Particularly preferred examples include the structure shown below. When the composition has such a structure, the flowability is improved, and the embedding and flattening properties are improved. In addition, the heat resistance and film-forming properties are improved, and the generation of sublimates during heat curing is suppressed, the contamination of the device due to the sublimates is suppressed, and the occurrence of coating defects can be suppressed. [ka] (In the above formula, * represents the bonding site to the oxygen atom.)

[0078] In the resin having the structural unit represented by the general formula (1-1), 02 Specific examples of the structure in which is represented by a monovalent organic group include, but are not limited to, the following. [ka] (In the above formula, R 00 is the same as above.)

[0079] In the resin having the structural unit represented by the above general formula (1-2), 02 Specific examples of the structure in which is represented by a monovalent organic group include, but are not limited to, the following. [ka]

[0080] Furthermore, in the above general formula (1-1) and general formula (1-2), 02In the structure constituting the present invention, when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', a' and b' satisfy the relationship of a'+b'=1, 0.1≦a'≦0.5, 0.5≦b'≦0.9. The relationship between a' and b' is preferably a'+b'=1, 0.1≦a'≦0.5, 0.5≦b'<0.9, more preferably a'+b'=1, 0.15≦a'≦0.4, 0.6≦b'≦0.85. When the ratio of b' is less than 0.5, the contribution of hydrogen bonds of phenolic hydroxyl groups increases, and the complex viscosity of the resin increases, resulting in a lower fluidity and a concern that the embedding characteristics may be deteriorated. When the ratio of b' is more than 0.9, the ratio of phenolic hydroxyl groups in the resin decreases, and the action with the base generator (B) becomes weak, resulting in a concern that the adhesion to the substrate to be processed may be deteriorated.

[0081] For example, when forming a thick resist underlayer film on a substrate to be processed, a resin with a low complex viscosity is preferable because it shows excellent film-forming properties and can reduce the consumption of chemicals. On the other hand, when the resin is hydrophobized to reduce the complex viscosity of the resin, a problem occurs in that the adhesion to the substrate to be processed is reduced. The composition for forming a resist underlayer film of the present invention can form a resist underlayer film with extremely excellent adhesion to the substrate by combining (A) resin with excellent fluidity and adhesion to the substrate and (B) base generator that has the effect of further improving the adhesion of the resin to the substrate.

[0082] Furthermore, in the above general formula (1-1), n1 is an integer of 1 to 5, preferably 1 or 2, and more preferably 1. Furthermore, in the above general formula (1-2), p is 0 or 1, and when p is 0, n2 is an integer of 1 to 4, and when p is 1, n2 is an integer of 1 to 6, and it is preferable that p is 0 and n2 is 1. A composition for forming a resist underlayer film containing such a structure exhibits extremely excellent filling properties even for a substrate to be processed having a large aspect ratio and a portion that is particularly difficult to fill, and can form a resist underlayer film that does not generate voids or peel off from the substrate to be processed.

[0083] Furthermore, in the above general formula (1-1), m1 is an integer of 0 to 4, and m1+n1 is an integer of 1 or more and 5 or less. Furthermore, in the above general formula (1-2), when p is 0, m2 is an integer of 0 to 3, and m2+n2 is an integer of 1 or more and 4 or less, and when p is 1, m2 is an integer of 0 to 5, and m2+n2 is an integer of 1 or more and 6 or less.

[0084] The weight average molecular weight of the (A) resin is 3,000 to 10,000. The weight average molecular weight is based on the value measured by gel permeation chromatography (tetrahydrofuran solvent, polystyrene standard). The weight average molecular weight of the (A) resin having the structural units represented by the general formula (1-1) and the general formula (1-2) is 3,000 to 10,000, preferably 4,000 to 9,500. If the weight average molecular weight is less than 3,000, the device is contaminated due to an increase in sublimates during film baking. On the other hand, if the weight average molecular weight exceeds 10,000, the thermal fluidity becomes insufficient and the embedding properties become poor. In this way, by adjusting the molecular weight of the resin to an appropriate range, it is possible to achieve both of the contradictory performances of the deterioration of embedding properties due to the deterioration of thermal fluidity associated with the increase in the molecular weight of the resin and the increase in sublimates due to low molecular weight components in the resin associated with the decrease in the molecular weight.

[0085] In addition, the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn of the (A) resin in terms of polystyrene by gel permeation chromatography is preferably 2.00≦Mw / Mn≦5.00, more preferably 2.50≦Mw / Mn≦4.00. If Mw / Mn is 5.00 or less, the device is not contaminated by an increase in sublimates during film firing. On the other hand, if the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn is 2.00 or more, the resin contains low molecular weight components, thereby exhibiting sufficient thermal fluidity and providing excellent embedding properties. In this way, by adjusting the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn of the resin to an appropriate range, it is possible to achieve both of the contradictory performances of the deterioration of embedding properties due to the deterioration of thermal fluidity caused by the monodispersion of the resin and the increase in sublimates due to the low molecular weight components in the resin caused by polydispersion.

[0086] In the present invention, the (A) resin may be used alone or in a mixture of two or more kinds. Alternatively, resins not containing the structural units represented by the above general formula (1-1) and general formula (1-2) may be used in a mixture. In this case, the resin that may be mixed is not particularly limited, and known resins may be used, but specifically, acrylic resins, styrene resins, phenolic resins, polyether resins, and epoxy resins are preferred.

[0087] The resist underlayer film forming composition of the present invention can be blended with other compounds or polymers depending on the purpose. The blending compound or blending polymer is mixed with a resin having the structural units represented by the above general formula (1-1) and general formula (1-2) and plays a role in improving the film forming properties of spin coating and the embedding properties on a substrate having a step. In addition, the blending compound or blending polymer is preferably a compound having a phenolic hydroxyl group.

[0088] Such materials 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, Phenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-t ert-Butyl-5-methylphenol, pyrogallol, thymol, isothymol, 4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-dimethyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-diallyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-difluoro-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-diphenyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'-dimethoxy-4,4'-(9H -fluoren-9-ylidene)bisphenol, 2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 3,3,3',3',4,4'-hexamethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 2,3,2',3'-tetrahydro-(1,1')-spirobiindene-5,5'-diol, 5,5'-dimethyl-3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene, 3-hydroxynaphthalene-2-methyl carboxylate, indene, hydroxyindene, benzofuran, hydroxyanthracene, acenaphthylene, and biphenyl. Examples of the novolak resins include bisphenol, trisphenol, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, norbornadiene, 5-vinylnorborn-2-ene, α-pinene, β-pinene, and limonene; polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyacenaphthylene, polynorbornene, polycyclodecene, polytetracyclododecene, polynortricyclene, poly(meth)acrylate, and copolymers thereof. In addition, naphthol dicyclopentadiene copolymers described in JP-A-2004-205685, fluorene bisphenol novolac resins described in JP-A-2005-128509, acenaphthylene copolymers described in JP-A-2005-250434, fullerenes having phenol groups described in JP-A-2006-227391, bisphenol compounds and novolac resins described in JP-A-2006-293298, adamantanephenol compounds and novolac resins described in JP-A-2006-285095, bisnaphthol compounds and novolac resins described in JP-A-2010-122656, and fullerene resin compounds described in JP-A-2008-158002 can also be blended.

[0089] [(B) Base generator] The composition for forming a resist underlayer film of the present invention contains the base generator (B), and therefore has good adhesion to the substrate to be processed, even when a thick resist underlayer film is formed, and the resist underlayer film can be formed without problems such as substrate peeling during dry etching. In order to maximize the effect of the base generator, it is preferable not to use an acid generator.

[0090] In the present invention, the base generator refers to a substance whose chemical structure changes in response to an external stimulus such as light or heat to generate a base, and is also called a "latent base", a "base precursor", etc. The base generated may be not only a general base such as ammonia or an amine, but also a chemical species having a function of increasing the ionicity of the phenolic hydroxyl group in the (A) resin.

[0091] The base generator of the component (B) is not particularly limited, and a known base generator can be used as necessary, but since it is assumed that when forming a film using the composition for forming a resist underlayer film of the present invention, heating is performed, and the phenolic hydroxyl group in the resin (A) becomes ionic during heating, and the interaction with the substrate is increased, thereby improving the film formability, it is preferable that the base generator (B) is a compound that develops basicity through thermal decomposition. This is because the composition for forming a resist underlayer film containing such a component (B) can achieve both the thermal fluidity of the film and the interaction with the substrate by adjusting the amount of the component (B) added.

[0092] In this way, when a base generator (also called a thermal base generator) that develops basicity by thermal decomposition is used as the (B) component, the generated base is a cation that becomes excessive in the system due to the evaporation or decomposition of an anion, specifically, triphenylsulfonium cation, tetrabutylammonium cation, etc. are mentioned. As a result, the ionicity (polarity) of the phenolic hydroxyl group in the (A) resin is increased, and even if the substrate is subjected to a hydrophobic treatment such as HMDS treatment, the adhesion between the composition for forming a resist underlayer film and the substrate is improved by interacting with polar groups such as silanol groups present on the surface. On the other hand, before heating, i.e., before base generation, the above-mentioned action does not occur, so the fluidity of the composition for forming a resist underlayer film itself is maintained. In this way, a resist underlayer film with excellent film-forming properties can be formed.

[0093] The base generator (B) is more preferably any one of those represented by the following general formulas (2), (3) and (4). [ka] (In the above formula, R 01 ~R 03 each independently represents a linear, branched or cyclic alkyl group, alkenyl group or aralkyl group having 1 to 10 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. 01 , R 02 and R 03 Any two of X may be bonded to each other to form a ring together with the sulfur atom in the formula. - represents an organic or inorganic counterion. - OH - Does not include R 04 and R 05are each independently an aryl group having 6 to 20 carbon atoms which may be substituted or interposed with a heteroatom, and some or all of the hydrogen atoms in the aryl group may be substituted with a linear, branched or cyclic alkyl or alkoxy group having 1 to 10 carbon atoms. 04 and R 05 may be bonded to each other to form a ring together with the iodine atom in the formula. 06 , R 07 , R 08 and R 09 each independently represents a hydrogen atom, or a linear, branched or cyclic alkyl group or alkenyl group having 1 to 20 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aralkyl group having 7 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. 06 , R 07 , R 08 and R 09 Any two or more of may be bonded to each other to form a ring together with the nitrogen atom in the formula.

[0094] R in the general formula (2) 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.

[0095] 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]

[0096] More specifically, the sulfonium cations 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, Examples of such sulfonium include 4-di-tert-butoxyphenyl)phenylsulfonium, tris(3,4-di-tert-butoxyphenyl)sulfonium, diphenyl(4-thiophenoxyphenyl)sulfonium, 10-phenylphenoxathiinium, 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, and (4-n-hexyloxy-3,5-dimethylphenyl)diphenylsulfonium. Further examples include 4-methacryloyloxyphenyl diphenyl sulfonium, 4-acryloyloxyphenyl diphenyl sulfonium, 4-methacryloyloxyphenyl dimethyl sulfonium, 4-acryloyloxyphenyl dimethyl sulfonium, (4-methacryloyloxy-3,5-dimethylphenyl)diphenyl sulfonium, and (4-acryloyloxy-3,5-dimethylphenyl)diphenyl sulfonium.More preferred are triphenylsulfonium, 4-tert-butylphenyldiphenylsulfonium, 4-tert-butoxyphenyldiphenylsulfonium, 10-phenylphenoxathiinium, S-phenyldibenzothiophenium, etc. Among these, more preferred are triphenylsulfonium, 4-tert-butylphenyldiphenylsulfonium, and 4-tert-butoxyphenyldiphenylsulfonium.

[0097] R in the general formula (3) 04 and R 05 Specific examples of the aryl group include a phenyl group, a naphthyl group, and the substitution position of the substituent is arbitrary. Examples of the aryl group include, but are not limited to, 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, and the like.

[0098] R 04 and R 05 As the aryl group, 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 the iodine atom is preferred, with a phenyl group, a 4-tert-butylphenyl group, a 4-fluorophenyl group and the like being particularly preferred.

[0099] R 04 and R 05When are bonded to each other directly or 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 to these. In addition, in the following formula, a substituent may be present at any position on the aromatic ring. [ka]

[0100] More specifically, examples of iodonium cations include, but are not limited to, those shown below. In the following formula, tBu is a tert-butyl group, and Ph is a phenyl group. [ka]

[0101] Examples of the ammonium cation represented by the general formula (4) include ammonium cations in which a proton is added to a nitrogen atom of ammonia, primary, secondary, or tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, a nitrogen-containing compound having a carboxy group, a nitrogen-containing compound having a sulfonyl group, a nitrogen-containing compound having a hydroxyl group, a nitrogen-containing compound having a hydroxyphenyl group, an alcoholic nitrogen-containing compound, or the like, and quaternary ammonium cations.

[0102] Specific examples of primary aliphatic amines 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, and 2-aminoethylammonium. Examples of secondary aliphatic amines include dimethylammonium, diethylammonium, di-n-propylammonium, diisopropylammonium, di-n-butylammonium, diisobutylammonium, di-sec-butylammonium, dipentylammonium, dicyclopentylammonium, dihex ... Examples of tertiary aliphatic amines 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, and dimethyl(2-dimethylaminoethyl)ammonium.

[0103] Examples of mixed amines include dimethylethylammonium, methylpropylammonium, benzylammonium, phenethylammonium, and benzyldimethylammonium. Specific examples of aromatic amines and heterocyclic amines 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, and N,N-dimethyltoluidinium at any substitution position), diphenyl(p-tolyl)ammonium, methyldiphenylammonium, triphenylammonium, aminophenylammonium at any substitution position, naphthylammonium, and 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, 2-methyl-1-pyrrolinium, pyrrolidinium derivatives (e.g. pyrrolidinium, N-methylpyrrolidinium, pyrrolidinonium, N-methylpyrrolidinium, 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, Examples include pyridinium, 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, quinolinium derivatives (e.g. quinolinium), isoquinolinium derivatives, cinnolinium derivatives, quinazolinium derivatives, quinoxalinium derivatives, phthalazinium derivatives, prenium derivatives, pteridinium derivatives, carbazolium derivatives, phenanthridinium derivatives, acridinium derivatives, phenazinium derivatives, 1,10-phenanthrolinium derivatives, etc.,

[0104] Further, examples of nitrogen-containing compounds having a carboxy group include carboxyphenylammonium, carboxyindolinium, and amino acid derivatives (e.g., proton addition products of nicotinic acid, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine, methionine, phenylalanine, threonine, lysine, 3-aminopyrazine-2-carboxylic acid, and methoxyalanine, etc.). Examples of nitrogen-containing compounds having a sulfonyl group include 3-pyridinium sulfonic acid, etc. Examples of nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, and alcoholic nitrogen-containing compounds include 2-hydroxypyridinium, hydroxyanilinium at any substitution position, hydroxy-methyl-anilinium at any substitution position, hydroxyquinolinium, dihydroxyquinolinium, 2-hydroxyethylammonium, biphenyl, phenylalanine ... Examples of the ammonium nitrile include 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-pyrrolidinonium, 2,3-dihydroxypropylpiperidinium, 2,3-dihydroxypropylpiperolidinium, 8-hydroxyyurolidinium, and 3-hydroxyquinuclidinium.

[0105] Specific examples of quaternary ammonium salts include tetramethylammonium, triethylmethylammonium, tetraethylammonium, tetrabutylammonium, tetraoctylammonium, didecyldimethylammonium, tridecylmethylammonium, hexadecyltrimethylammonium, stearyltrimethylammonium, benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, and 2-hydroxyethyltrimethylammonium.

[0106] As the ammonium cation, a quaternary ammonium cation is preferred, and in particular, a tetramethylammonium cation, a tetraethylammonium cation, or a tetrabutylammonium cation is preferred.

[0107] In this case, X in the general formulas (2), (3) and (4) - is more preferably any one of a structure represented by any one of the following general formulas (5), (6), and (7), a chloride ion, a bromide ion, an iodide ion, a fluoride ion, a cyanide ion, a nitrate ion, and a nitrite ion.

[0108] [ka] (In the above formula, R 10 R represents an ether group, an ester group, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, 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. 11 R represents an aryl group having 6 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. 12 , R 13 , R 14each independently represents a hydrogen atom, a halogen atom other than a fluorine atom, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain an ether group, an ester group or a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, in which one or more hydrogen atoms may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. 12 , R 13 , R 14 Two or more of may be bonded to each other to form a ring.)

[0109] Specific examples of the carboxylate anion represented by the general formula (5) include a formate anion, an acetate anion, a propionate anion, a butyrate anion, an isobutyrate anion, a valerate anion, an isovalerate anion, a pivalate anion, a hexanoate anion, an octanoate anion, a cyclohexanecarboxylate anion, a cyclohexylacetate anion, a laurate anion, a myristic acid anion, a palmitate anion, a stearate anion, a phenylacetate anion, a diphenylacetate anion, a phenoxyacetate anion, a mandelate anion, a benzoylformate anion, a cinnamate anion, a dihydrocinnamate anion, a benzoate anion, a methylbenzoate anion, a salicylate anion, a naphthalenecarboxylate anion, an anthracenecarboxylate anion, and an anthraquinone anion. Examples of the anion include a carboxylate anion, a hydroxyacetate anion, a pivalate anion, a lactate anion, a methoxyacetate anion, a 2-(2-methoxyethoxy)acetate anion, a 2-(2-(2-methoxyethoxy)ethoxy)acetate anion, a diphenolate anion, a monochloroacetate anion, a dichloroacetate anion, a trichloroacetate anion, a trifluoroacetate anion, a pentafluoropropionate anion, a heptafluorobutyrate anion, and a 2-hydroxy-2,2-bis(trifluoromethyl)acetate anion. Examples of the anion include a monoanion of a dicarboxylic acid such as succinic acid, tartaric acid, glutaric acid, pimelic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, and cyclohexenedicarboxylic acid.

[0110] Specific examples of the arenesulfonate anion represented by the general formula (6) 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, and dodecylbenzenesulfonate.

[0111] Specific examples of the alkane sulfonate anion represented by the general formula (7) include methanesulfonate, ethanesulfonate, propanesulfonate, butanesulfonate, pentanesulfonate, hexanesulfonate, cyclohexanesulfonate, octanesulfonate, and 10-camphorsulfonate.

[0112] Furthermore, X in the general formulas (2), (3) and (4) - It is more preferable that the boiling point of the conjugate acid XH is not higher than 200° C. In this specification, the boiling point is the value at 1 atmospheric pressure (1013 hPa).

[0113] X in the general formulas (2), (3) and (4) - Particularly preferred are trifluoroacetate anion, pentafluoropropionate anion, 2-hydroxy-2,2-bis(trifluoromethyl)acetate anion, chloride ion, and nitrate ion.

[0114] The base generator (B) may be any combination of the specific examples of the cations and the specific examples of the anions described above, but is not limited thereto. In addition, preferred structures include those shown below. In the following formula, tBu is a tert-butyl group. [ka]

[0115] The (B) base generator can be used alone or in combination of two or more to exhibit basicity in accordance with the baking temperature of the composition for forming a resist underlayer film, and the balance between film formability on a hydrophobic substrate and flatness can be appropriately adjusted. When the (B) base generator is added, the amount of the (B) base generator is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, relative to 100 parts by mass of the (A) resin. When the (B) base generator is added in an amount within the above range, a sufficient film formability improving effect can be obtained, and problems such as deterioration of the in-plane uniformity of the film due to decomposition and sublimation and deterioration of the curability of the compound or resin due to basicity do not occur.

[0116] The base generator (B) used in the composition for forming a resist underlayer film of the present invention is more preferably one represented by the above general formula (2) or general formula (4), and particularly preferably one represented by the above general formula (2).

[0117] [(C) Organic solvent] The (C) organic solvent that can be used in the composition for forming a resist underlayer film of the present invention is not particularly limited as long as it can dissolve or disperse the (A) resin and the (B) base generator, and is preferably one that can also dissolve or disperse the (D) crosslinking agent, (E) flow promoter, (F) surfactant, and (G) plasticizer, which will be described later.

[0118] Specifically, the organic solvents described in paragraphs

[0091] to

[0092] of JP 2007-199653 A 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, γ-butyrolactone, or a mixture containing one or more of these is preferably used.

[0119] The amount of the organic solvent is preferably adjusted according to the set film thickness of the resist underlayer film, but is usually preferably in the range of 100 to 50,000 parts by mass relative to 100 parts by mass of the (A) resin, and in order to form a thick resist underlayer film, it is more preferably 100 to 400 parts by mass, further preferably 100 to 300 parts by mass, particularly preferably 100 to 250 parts by mass, and most preferably 100 to 200 parts by mass. By using such an amount of the organic solvent, it is possible to form a thicker resist underlayer film, and the composition for forming the resist underlayer film of the present invention, which has excellent filling properties and substrate adhesion, can be more preferably used.

[0120] [(D) Crosslinking agent] In addition, a crosslinking agent (D) can be added to the resist underlayer film forming composition of the present invention. The crosslinking agent used is not particularly limited, and various known crosslinking agents can be widely used. Examples include methylol or alkoxymethyl type crosslinking agents of polynuclear phenols (polynuclear phenol crosslinking agents), melamine crosslinking agents, glycoluril crosslinking agents, benzoguanamine crosslinking agents, urea crosslinking agents, β-hydroxyalkylamide crosslinking agents, isocyanurate crosslinking agents, aziridine crosslinking agents, oxazoline crosslinking agents, and epoxy crosslinking agents. Among these, polynuclear phenol crosslinking agents are particularly preferred. The amount of the crosslinking agent added is preferably 1 to 50 parts by mass, more preferably 5 to 30 parts by mass, based on 100 parts by mass of the (A) resin.

[0121] The resist underlayer film forming composition of the present invention contains the above-mentioned (D) crosslinking agent, which improves the thermosetting property of the (A) resin, and is effective in eliminating the generation of voids due to the residual solvent in the resin, which is a problem when filling a high aspect ratio pattern, and is preferable for improving the filling property. In particular, a polynuclear phenol-based crosslinking agent is preferable because it acts with the (B) base generator contained in the resist underlayer film forming composition of the present invention and contributes to improving adhesion.

[0122] Specific examples of the melamine-based crosslinking agent include hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0123] Specific examples of glycoluril crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy and / or hydroxy substituted products thereof, and partial self-condensates thereof.

[0124] Specific examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof.

[0125] Specific examples of the urea-based crosslinking agent include dimethoxymethylated dimethoxyethyleneurea, its alkoxy and / or hydroxyl substituted derivatives, and partial self-condensates thereof.

[0126] A specific example of the β-hydroxyalkylamide crosslinking agent is N,N,N',N'-tetra(2-hydroxyethyl)adipamide.

[0127] Specific examples of the isocyanurate crosslinking agent include triglycidyl isocyanurate and triallyl isocyanurate.

[0128] Specific examples of the aziridine crosslinking agent include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate].

[0129] Specific examples of the oxazoline-based crosslinking agent include 2,2'-isopropylidenebis(4-benzyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis4,5-diphenyl-2-oxazoline, 2,2'-methylenebis-4-phenyl-2-oxazoline, 2,2'-methylenebis-4-tertbutyl-2-oxazoline, 2,2'-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyloxazoline copolymer.

[0130] Specific examples of epoxy crosslinking agents 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.

[0131] Specific examples of polynuclear phenol-based crosslinking agents include compounds represented by the following general formula (XL-1). [ka] (In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5.)

[0132] 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 is 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. R3 is 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, and a hydrogen atom or a methyl group is preferred.

[0133] Specific examples of the compound represented by the above general formula (XL-1) include the following compounds. Among these, from the viewpoint of improving the curability and thickness uniformity of the organic film, hexamethoxymethylated triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred. R3 is the same as above. [ka]

[0134] [ka]

[0135] [(E) Flow enhancer] Furthermore, the composition for forming a resist underlayer film of the present invention can contain (E) a flowability promoter that has a weight loss rate of less than 30% at temperatures from 30°C to 190°C and a weight loss rate of 98% or more at temperatures from 30°C to 350°C.

[0136] A flowability promoter that has a weight loss rate of less than 30% from 30° C. to 190° C. and a weight loss rate of 98% or more from 30° C. to 350° C. is preferred because evaporation during heat treatment is suppressed, thereby maintaining a low viscosity sufficiently, the flowability promoter is excellent in thermal fluidity, and little flowability promoter remains in the resist underlayer film after baking. In this specification, the weight loss rate is based on a value determined by TG (thermogravimetry) measurement using a differential thermobalance.

[0137] The upper limit of the temperature range in which the weight loss rate of the (E) fluidity promoter is less than 30% is more preferably 210° C., and even more preferably 230° C. By setting the temperature range in which the weight loss rate of the fluidity promoter is less than 30% within the above temperature range, the filling / planarization characteristics can be further improved.

[0138] The upper limit of the temperature range at which the weight loss rate of the (E) fluidity promoter is 98% or more is more preferably 330° C., and particularly preferably 310° C. By setting the temperature at which the weight loss rate of the fluidity promoter is 98% or more within the above temperature range, it is possible to further reduce the amount of fluidity promoter remaining in the resist underlayer film after baking.

[0139] By incorporating the above-mentioned (E) flowability promoter, the thermal flowability of the composition for forming a resist underlayer film is improved from the start of heat treatment to curing by crosslinking reaction, resulting in excellent filling / planarization properties. On the other hand, the (E) flowability promoter is reduced by evaporation or the like during heat treatment, so that etching resistance and optical properties are not impaired.

[0140] More preferred embodiments of the above (E) flow promoter include one or more compounds selected from the following general formulas (i) to (iii). [ka] (In the formula, R 1 are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms. 1 W is a phenylene group or a divalent group represented by the following general formula (i-1).2 , W 3 is a single bond or a divalent group represented by the following general formula (i-2): 1 is an integer from 1 to 10, and n 1 is an integer between 0 and 5.) [ka] (In the formula, * indicates a bond position, and R 10 , R 11 , R 12 , R 13 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. 10 , W 11 Each of m is independently a single bond or a carbonyl group. 10 , m 11 is an integer from 0 to 10, and m 10 +m 11 ≧1.) [ka] (In the formula, * indicates the bond position.) [ka] (In the formula, R 2 are each independently a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms. 4 W is a divalent group represented by the following general formula (ii-1). 5 is a single bond or a divalent group represented by the following general formula (ii-2): 2 is an integer from 2 to 10, and n 3 is an integer between 0 and 5.) [ka] (In the formula, * indicates a bond position, and R 20 , R 21 , R 22 , R 23 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. 20 , m 21 is an integer from 0 to 10, and m 20 +m21 ≧1.) [ka] (In the formula, * indicates the bond position.) [ka] (In the formula, R 3 , R 4 R is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and may be bonded to each other to form a cyclic structure. 5 , R 6 is an organic group having 1 to 10 carbon atoms, R 5 is a group containing either an aromatic ring or a divalent group represented by the following general formula (iii-1): 6 , W 7 is a single bond or a divalent group represented by the following general formula (iii-2), and at least one of them is a divalent group represented by (iii-2). [ka] (In the formula, * indicates a bond position, and W 30 is an organic group having 1 to 4 carbon atoms. [ka] (In the formula, * indicates the bond position.)

[0141] In the above general formula (i), R 1 are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms. Here, in the present invention, the term "organic group" means a group containing at least one carbon atom, and may further contain a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, a halogen atom, or the like.

[0142] R 1 R may be a single type or a mixture of multiple types. 1More specifically, examples of the alkyl group include a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a vinyl group, a 2,2,2-trifluoroethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, a s-butyl group, a t-butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a cyclohexenyl group, a decyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a s-butoxy group, a t-butoxy group, a norbornyl group, an adamantyl group, a phenyl group, a toluyl group, a xylyl group, a naphthyl group, a benzyl group, a 2-furanyl group, and a 2-tetrahydrofuranyl group. Among these, a hydrogen atom is more preferable.

[0143] W 1 is a phenylene group or a divalent group represented by the above general formula (i-1). 2 , W 3 is a single bond or a divalent group represented by the above general formula (i-2). 1 is an integer from 1 to 10, and n 1 each independently represents an integer of 0 to 5.

[0144] R 10 , R 11 , R 12 , R 13 More specifically, it is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. More specifically, it is possible to exemplify a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a vinyl group, a 2,2,2-trifluoroethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, a s-butyl group, a t-butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a cyclohexenyl group, a decyl group, a methoxy group, an ethoxy group, a propoxy group, a isopropoxy group, a butoxy group, a s-butoxy group, a t-butoxy group, a norbornyl group, an adamantyl group, a phenyl group, a toluyl group, a xylyl group, a naphthyl group, a benzyl group, a 2-furanyl group, and a 2-tetrahydrofuranyl group. Among these, a hydrogen atom and a methyl group are more preferred, and a hydrogen atom is even more preferred.

[0145] W 10 , W 11Each of m is independently a single bond or a carbonyl group. 10 , m 11 is an integer from 0 to 10, and m 10 +m 11 ≧1.

[0146] In the above general formula (ii), R 2 are each independently a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms.

[0147] R 2 R may be a single type or a mixture of multiple types. 2 More specifically, examples of the alkyl group include a hydrogen atom, a methyl group, an ethyl group, a vinyl group, a 2,2,2-trifluoroethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, a s-butyl group, a t-butyl group, an isobutyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a cyclohexenyl group, a decyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a s-butoxy group, a t-butoxy group, a norbornyl group, an adamantyl group, a phenyl group, a toluyl group, a xylyl group, a naphthyl group, a benzyl group, a 2-furanyl group, and a 2-tetrahydrofuranyl group. Among these, a hydrogen atom is more preferable.

[0148] W 4 is a divalent group represented by the above general formula (ii-1). 5 is a single bond or any divalent group represented by the above general formula (ii-2). 2 is an integer from 2 to 10, and n 3 is an integer between 0 and 5.

[0149] R 20 , R 21 , R 22 , R 23More specifically, hydrogen atom, hydroxyl group, methyl group, ethyl group, vinyl group, 2,2,2-trifluoroethyl group, propyl group, isopropyl group, allyl group, butyl group, s-butyl group, t-butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclohexenyl group, decyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, s-butoxy group, t-butoxy group, norbornyl group, adamantyl group, phenyl group, toluyl group, xylyl group, naphthyl group, benzyl group, 2-furanyl group, 2-tetrahydrofuranyl group can be exemplified. Among these, hydrogen atom and methyl group are more preferable, and hydrogen atom is more preferable.

[0150] m 20 , m 21 is an integer from 0 to 10, and m 20 +m 21 ≧1.

[0151] In the above general formula (iii), R 3 , R 4 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and may be bonded to each other to form a cyclic structure. More specifically, hydrogen atom, hydroxyl group, methyl group, ethyl group, vinyl group, 2,2,2-trifluoroethyl group, propyl group, isopropyl group, allyl group, butyl group, s-butyl group, t-butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, cyclohexenyl group, decyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, s-butoxy group, t-butoxy group, norbornyl group, adamantyl group, phenyl group, toluyl group, xylyl group, naphthyl group, benzyl group, 2-furanyl group, and 2-tetrahydrofuranyl group can be exemplified. Among these, hydrogen atom is more preferable.

[0152] R 5 R is an organic group having 1 to 10 carbon atoms and containing either an aromatic ring or a divalent group represented by the above general formula (iii-1). 6is an organic group having 1 to 10 carbon atoms. The organic group having 1 to 10 carbon atoms includes the above R 3 , R 4 Examples of the groups include those mentioned above.

[0153] W 6 , W 7 is either a single bond or a divalent group represented by the above general formula (iii-2), and at least one of these is a divalent group represented by the above general formula (iii-2).

[0154] W 30 is an organic group having 1 to 4 carbon atoms. More specific examples include a methylene group, an ethylene group, a propylene group, a butylene group, a trimethylene group, and a tetramethylene group. Among these, an ethylene group is more preferable.

[0155] More specific examples of the compound represented by the above general formula (i) include, but are not limited to, the following. [ka]

[0156] More specific examples of the compound represented by the above general formula (ii) include, but are not limited to, the following. [ka]

[0157] More specific examples of the compound represented by the above general formula (iii) include, but are not limited to, the following: [ka]

[0158]

[0113] In consideration of the film-forming properties in the composition for forming a resist underlayer film, the performance of embedding / planarizing the substrate, and the like, the flowability promoter (E) used in the composition for forming a resist underlayer film of the present invention is preferably an aromatic-containing compound having a benzyl group or a benzoyl group, and in particular, the following aromatic-containing compounds are preferable. (i) (Poly)ethylene glycol dibenzoate (ii) (Poly)ethylene glycol dibenzyl ether (iii) (Poly)propylene glycol dibenzyl ether (iv) (Poly)butylene glycol dibenzyl ether (v) Dibenzyl linear aliphatic dicarboxylate (vi) (Poly)ethylene glycol monobenzyl ether (vii) (Poly)phenyl ethers

[0159] [ka] In the above formula, n is an integer that results in a molecular weight in the range of 500 or less, and is only applicable within this formula.

[0160] The (E) fluidity promoter used in the composition for forming a resist underlayer film of the present invention preferably has a structure having both a hydrophobic part consisting of an aromatic ring and a hydrophilic part consisting of the following (E-1) structure. Such a (E) fluidity promoter has excellent compatibility with the (A) resin, the (B) base generator, the (C) organic solvent and other additives, and can improve the fluidity of the composition without impairing the film-forming property or storage stability. [ka] (In the formula, * indicates a bonding position, and W is an organic group having 1 to 4 carbon atoms.)

[0161] The blending amount of the (E) fluidity promoter is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, based on 100 parts by mass of the (A) resin. When the blending amount of the (E) fluidity promoter based on the (A) resin is 5 parts by mass or more, the effect of improving the thermal fluidity of the resist underlayer film is sufficiently obtained. On the other hand, when the blending amount of the (E) fluidity promoter is 100 parts by mass or less, the film formability and dry etching resistance of the obtained coating film are good.

[0162] As the (E) flow promoter, the above aromatic-containing compounds can be used alone or in combination of two or more.

[0163] In addition, it is preferable that the composition for forming a resist underlayer film further contains at least one of (F) a surfactant and (G) a plasticizer.

[0164] [(F) Surfactant] To improve the coating property in spin coating, a surfactant (F) can be added to the resist underlayer film forming composition of the present invention. For example, the surfactants described in paragraphs

[0142] to

[0147] of JP2009-269953A can be used as the surfactant (F). When the surfactant (F) is added, the amount of the surfactant is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the resin (A).

[0165] [(G) Plasticizer] In addition, in order to further improve the planarization / filling properties, a plasticizer (G) can be added to the composition for forming a resist underlayer film of the present invention. The plasticizer (G) is not particularly limited, and various known plasticizers can be widely used. Examples include low molecular weight compounds such as phthalates, adipic esters, phosphates, trimellitates, and citrates, polyethers, polyesters, and polymers such as the polyacetal polymers described in JP-A-2013-253227. When a plasticizer (G) is added, the amount of the plasticizer is preferably 1 to 100 parts by mass, more preferably 5 to 30 parts by mass, based on 100 parts by mass of the resin (A).

[0166] In addition, in the composition for forming a resist underlayer film of the present invention, as an additive for imparting filling / flattening properties in the same manner as a plasticizer, for example, a liquid additive having a polyethylene glycol or polypropylene glycol structure, or a thermally decomposable polymer having a weight loss rate of 40% by mass or more between 30° C. and 250° C. and a weight average molecular weight of 300 to 200,000 is preferably used. This thermally decomposable polymer preferably contains a repeating unit having an acetal structure represented by the following general formula (DP1) or (DP1a).

[0167] [ka] (In the formula, R6 is a hydrogen atom or an optionally substituted saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms. Y is a saturated or unsaturated divalent organic group having 2 to 30 carbon atoms.)

[0168] [ka] (In the formula, R 6a is an alkyl group having 1 to 4 carbon atoms. a is a saturated or unsaturated divalent hydrocarbon group having 4 to 10 carbon atoms, which may have an ether bond; and n represents the average number of repeating units and is 3 to 500.

[0169] [Pattern formation method using composition for forming resist underlayer film] In addition, in the present invention, there is provided a method for forming a pattern by a two-layer resist process using the composition for forming a resist underlayer film, comprising the steps of: (I-1) a step of applying the composition for forming a resist underlayer film onto a substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a photoresist material; (I-3) a step of forming a pattern on the resist upper layer film by pattern-exposing the resist upper layer film and then developing the resist upper layer film 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 pattern has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0170] The resist upper layer film in the two-layer resist process is preferably a photosensitive organometallic oxide film. The photosensitive organometallic oxide film exhibits resistance to etching by oxygen-based gas, so that in the two-layer resist process, the dry etching of the resist lower layer film using the resist upper layer film as a mask is preferably performed using an etching gas mainly containing oxygen-based gas.

[0171] In addition, in the present invention, a method for forming a pattern by a three-layer resist process using such a composition for forming a resist underlayer film is provided, (II-1) a step of applying the composition for forming a resist underlayer film onto a substrate to be processed, followed by heat treatment to form a resist underlayer film; (II-2) forming a resist intermediate film on the resist underlayer film; (II-3) 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 pattern-exposing the resist upper layer film and then developing the resist upper layer film 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 on which the pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the resist intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of:

[0172] The resist intermediate film in the above three-layer resist process can be a silicon-containing resist intermediate film, which exhibits resistance to etching by oxygen-based gas. Therefore, in the above three-layer resist process, it is preferable that the dry etching of the resist underlayer film performed using the silicon-containing resist intermediate film as a mask is performed using an etching gas mainly composed of an oxygen-based gas.

[0173] A pattern formation method by a three-layer resist process will be described with reference to Fig. 1. In the present invention, as a pattern formation method by a three-layer resist process using such a resist underlayer film formation method, as shown in Fig. 1(A), a resist underlayer film 3 is formed on a processable layer 2 on a processable substrate 1 using the above-mentioned resist underlayer film forming composition, a silicon-containing resist intermediate film 4 is formed on the resist underlayer film using a silicon-containing resist intermediate film material, and a resist upper layer film 5 is formed on the silicon-containing resist intermediate film using a photoresist material. Subsequently, as shown in FIG. 1(B), an exposed portion 6 of the resist top layer film is exposed to a pattern, and then, as shown in FIG. 1(C), it is developed with a developer to form a resist top layer film pattern 5a on the resist top layer film. As shown in FIG. 1(D), using the patterned resist top layer film as a mask, a silicon-containing resist intermediate film pattern 4a is transferred to the silicon-containing resist intermediate film by dry etching. As shown in FIG. 1(E), using the patterned silicon-containing resist intermediate film as a mask, a resist underlayer film pattern 3a is transferred to the resist underlayer film by dry etching. As shown in FIG. 1(F), a pattern forming method is provided in which the processable layer on the processable substrate is processed by using the patterned resist underlayer film as a mask to form a pattern 2a on the processable substrate 1.

[0174] As the silicon-containing resist intermediate film in the above three-layer resist process, a polysiloxane-based intermediate film is also preferably used. By imparting an anti-reflection effect to the silicon-containing resist intermediate film, reflection can be suppressed. In particular, for 193 nm exposure, if a material containing many aromatic groups and having high etching selectivity with the substrate is used as the resist underlayer film, the k value becomes high and the substrate reflection becomes high, but by imparting absorption to the silicon-containing resist intermediate film so that the k value becomes appropriate, it is possible to suppress reflection, and the substrate reflection can be reduced to 0.5% or less. As the silicon-containing resist intermediate film having an anti-reflection effect, anthracene is preferably used for 248 nm and 157 nm exposure, and polysiloxane with a pendant light-absorbing group having a phenyl group or a silicon-silicon bond and crosslinked by acid or heat is preferably used for 193 nm exposure.

[0175] In addition, in the present invention, a pattern forming method by a four-layer resist process using such a composition for forming a resist underlayer film is provided, forming a resist underlayer film on a substrate to be processed using the composition for forming a resist underlayer film; forming a silicon-containing resist intermediate film on the resist underlayer film using a silicon-containing resist intermediate film material; forming an organic antireflective coating (BARC) or an adhesion film on the silicon-containing resist intermediate film; forming a resist top layer film on the BARC or the adhesion film using a photoresist material; The resist upper layer film is exposed to a pattern and then developed with a developer to form a pattern on the resist upper layer film; Using the resist top layer film on which the pattern is formed as a mask, a pattern is transferred to the BARC or the adhesion film and the silicon-containing resist intermediate film by dry etching; using the silicon-containing resist intermediate film to which the pattern has been transferred as a mask, transferring the pattern to the resist underlayer film by dry etching; The present invention provides a pattern forming method, comprising the 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.

[0176] In addition, an inorganic hard mask intermediate film may be formed instead of the silicon-containing resist intermediate film. In this case, (III-1) a step of applying the composition for forming a resist underlayer film onto a substrate to be processed, and then heat-treating the composition to form a resist underlayer 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 underlayer film; (III-3) forming an organic thin film on the inorganic hard mask intermediate film; (III-4) forming a resist top layer film on the organic thin film using a photoresist material; (III-5) a step of forming a pattern on the resist upper layer film by pattern-exposing the resist upper layer film and then developing the resist upper layer film with a developer; (III-6) a step of transferring a 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 has been formed as a mask; (III-7) a step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. The present invention provides a pattern forming method comprising the steps of: forming a semiconductor device circuit pattern on a substrate;

[0177] As described above, when forming an inorganic hard mask intermediate film on a resist underlayer film, a silicon oxide film, a silicon nitride film, and a silicon oxide nitride film (SiON film) can be formed by a CVD method, an ALD method, or the like. For example, methods for forming a silicon nitride film are described in JP-A-2002-334869 and WO-A-2004 / 066377. The thickness of the inorganic hard mask intermediate film is preferably 5 to 200 nm, more preferably 10 to 100 nm. In addition, a SiON film, which has a high effect as an anti-reflection film, is most preferably used as the inorganic hard mask intermediate film. Since the substrate temperature when forming the SiON film is 300 to 500°C, the resist underlayer film needs to withstand a temperature of 300 to 500°C. The composition for forming the resist underlayer film used in the present invention has high heat resistance and can withstand high temperatures of 300 to 500°C, so that it is possible to combine an inorganic hard mask intermediate film formed by a CVD method or an ALD method with a resist underlayer film formed by a spin coating method.

[0178] As described above, a photoresist film may be formed on the inorganic hard mask intermediate film as a resist top layer, but an organic anti-reflective coating (BARC) or adhesion film may be formed on the inorganic hard mask intermediate film by spin coating, and a photoresist film may be formed on top of that. In particular, when a SiON film is used as the inorganic hard mask intermediate film, the two-layer anti-reflective coating of the SiON film and the BARC makes it possible to suppress reflection even in immersion exposure with a high NA exceeding 1.0. Another advantage of forming the BARC is that it has the effect of reducing the tailing of the photoresist pattern directly above the SiON film.

[0179] In the above pattern forming method, the resist upper layer film may be either positive or negative, and may be the same as a commonly used photoresist composition. The photoresist composition may contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, and Zn. When the resist upper layer film is formed using the above photoresist composition, it may be formed by a spin coating method or a deposition process using a CVD method or an ALD method.

[0180] When forming a photoresist composition by spin coating, the resist is prebaked after coating, preferably at 60 to 180° C. for 10 to 300 seconds. Thereafter, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist pattern. The thickness of the resist top layer is not particularly limited, but is preferably 10 to 500 nm, particularly preferably 20 to 400 nm.

[0181] When forming a photoresist composition by deposition processing using a CVD method or an ALD method, the resist composition is preferably an EUV photosensitive metal oxide film, and the metal is selected from Sn, Zr, Hf, Ti, Bi, Sb, etc., and among them, Sn, which has excellent EUV photosensitivity, is preferred. The metal oxide-containing film may be a photosensitive organometallic oxide film such as an organotin oxide (e.g., haloalkyl Sn, alkoxyalkyl Sn, or amidoalkyl Sn). Some specific examples of suitable precursors include trimethyltin chloride, dimethyltin dichloride, methyltin trichloride, tris(dimethylamino)methyltin(IV), and (dimethylamino)trimethyltin(IV).

[0182] Metal oxide films may be deposited by PECVD or PEALD, for example using a Lam Vector® tool, where the Sn oxide precursor can be separated from the O precursor / plasma in the ALD embodiment. The deposition temperature is preferably in the range of 50° C. to 600° C. The deposition pressure is preferably between 100 and 6,000 mTorr. The flow rate of the metal oxide-containing film precursor liquid (e.g., organotin oxide precursor) may be 0.01 to 10 cmm, and the gas flow rate (CO2, CO, Ar, N2) may be 100 to 10,000 sccm. The plasma power may be 200 to 1,000 W per 300 mm wafer station using a high frequency plasma (e.g., 13.56 MHz, 27.1 MHz, or higher). The deposition thickness is preferably 100 to 2,000 Å.

[0183] Examples of the exposure light include high energy rays with a wavelength of 300 nm or less, specifically, excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, and X-rays.

[0184] The method for forming the pattern on the resist upper layer film is preferably photolithography with a wavelength of 5 nm or more and 300 nm or less, direct drawing with an electron beam, nanoimprinting, or a combination of these.

[0185] In the pattern forming method, the development method is preferably alkaline development or development using an organic solvent.

[0186] Next, etching is performed using the obtained resist pattern as a mask. In the three-layer resist process, etching of the silicon-containing resist intermediate film and the inorganic hard mask intermediate film is performed using a fluorocarbon-based gas as a mask for the upper resist pattern. This forms a silicon-containing resist intermediate film pattern and an inorganic hard mask intermediate film pattern.

[0187] Next, the resist underlayer film is etched using the silicon-containing resist intermediate film pattern or the inorganic hard mask intermediate film pattern as a mask. The etching of the resist underlayer film is preferably carried out using an etching gas mainly containing an oxygen-based gas.

[0188] The next etching of the workpiece can also be done by a normal method, for example, if the workpiece is SiO2, SiN, or a silica-based low dielectric constant insulating film, etching can be done mainly with fluorocarbon gases. When etching the substrate with fluorocarbon gases, the silicon-containing resist intermediate film pattern in the three-layer resist process is peeled off at the same time as the substrate is processed.

[0189] The resist underlayer film obtained from the composition for forming a resist underlayer film of the present invention is characterized by excellent etching resistance when etching the workpiece.

[0190] The workpiece (substrate) is not particularly limited, and may be a substrate such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, or Al, or a substrate on which a layer to be processed is formed. As the layer to be processed, various low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, or Al-Si and their stopper films are used, and may be formed to a thickness of usually 50 to 10,000 nm, particularly 100 to 5,000 nm. When forming a layer to be processed, the substrate and the layer to be processed are made of different materials.

[0191] [Method for forming resist underlayer film] The present invention can provide a method for forming a resist underlayer film that functions as an organic embedded film used in a manufacturing process of a semiconductor device, comprising spin-coating the composition for forming a resist underlayer film described above onto a substrate to be processed, and heat-treating the substrate to which the composition for forming a resist underlayer film has been applied at a temperature of 100° C. or higher and 600° C. or lower for 10 to 600 seconds to form a cured film.

[0192] In addition, there can be provided a method for forming a resist underlayer film that functions as an organic embedded film used in a manufacturing process of a semiconductor device, comprising spin-coating the composition for forming a resist underlayer film described above onto a substrate to be processed, and heat-treating the substrate to which the composition for forming a resist underlayer film has been applied in an atmosphere with an oxygen concentration of 1% or more and 21% or less to form a cured film.

[0193] Alternatively, there can be provided a method for forming a resist underlayer film that functions as an organic embedded film used in a manufacturing process of a semiconductor device, the method comprising spin-coating the composition for forming a resist underlayer film described above onto a substrate to be processed, and heat-treating the substrate to which the composition for forming a resist underlayer film has been applied in an atmosphere with an oxygen concentration of less than 1%, thereby forming a cured film.

[0194] In the method for forming a resist underlayer film of the present invention, the composition for forming a resist underlayer film 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 properties can be obtained. After spin coating, the solvent is evaporated, and baking is performed to promote a crosslinking reaction in order to prevent mixing with the resist top layer film or the silicon-containing resist intermediate film. Baking is preferably performed at a temperature range of 100°C to 600°C, more preferably 100°C to 400°C, and even more preferably 150°C to 350°C, and is preferably performed within a range of 10 seconds to 600 seconds, and more preferably 10 to 300 seconds. By appropriately adjusting the baking temperature and time within the above ranges, planarization, embedding properties, and hardening properties suitable for the application can be obtained. A baking temperature of 100°C or higher is preferable because hardening proceeds sufficiently and mixing with the resist top layer film or the silicon-containing resist intermediate film does not occur. A bake temperature of 600° C. or less is preferable because it is possible to suppress thermal decomposition of the base resin, the film thickness is not reduced, and the film surface becomes uniform.

[0195] The resist underlayer film preferably has a thickness of at least 2 μm, more preferably at least 3 μm, and even more preferably at least 5 μm.

[0196] Such a resist underlayer film is advantageous in filling high aspect ratio patterns because it can further improve the filling characteristics, and is also preferable because it can exhibit excellent transfer performance in transferring a pattern to a substrate to be processed.

[0197] Furthermore, in the pattern forming method of the present invention, the resist underlayer film is preferably formed by a spin coating method, and the method for forming the resist underlayer film is preferably such that the composition for forming a resist underlayer film of the present invention is applied once to coat the resist underlayer film to a thickness of at least 2 μm, more preferably at least 3 μm, and even more preferably at least 5 μm.

[0198] Such a pattern formation method is preferable from the viewpoint of device productivity since it is possible to form a thick resist underlayer film by a single coating.

[0199] The atmosphere during baking can be selected as necessary from either an oxygen-containing atmosphere such as air (oxygen concentration 1% to 21%) or an oxygen-free atmosphere such as nitrogen. For example, if the substrate to be processed is susceptible to air oxidation, substrate damage can be suppressed by forming a hardened film by performing heat treatment in an atmosphere with an oxygen concentration of less than 1%.

[0200] The pattern forming method of the present invention also preferably uses, as the substrate to be processed, a substrate having a structure or steps with an aspect ratio of 5 or more. The pattern forming method of the present invention is particularly useful when forming a resist underlayer film without voids on a substrate having a structure or steps with an aspect ratio of 5 or more, particularly an aspect ratio of 10 or more. EXAMPLES

[0201] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these descriptions. The molecular weight and dispersity were measured by the following method. The weight average molecular weight (Mw) and dispersity (Mw / Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent.

[0202] Resins (X-1) to (X-12) of the composition for forming a resist underlayer film and resins (R-2), (R-3), (R-5), and (R-7) for comparative examples were synthesized by synthesizing intermediate resins (A-1) to (A-8) using resin raw materials (b-1) to (b-9) shown below, and controlling the reaction rate using modifying agents (c-1) to (c-3). Resin (R-1) for comparative examples was resin (A-1), resin (R-4) for comparative examples was resin (A-3), and resin (R-6) for comparative examples was resin (A-4). Resin raw material (b-8) was used as a raw material using a 37% aqueous solution.

[0203] Resin raw material: [ka]

[0204] Resins used as intermediates: [ka]

[0205] Modifiers: [ka]

[0206] The above-described resins (A-1) to (A-8) were synthesized as follows.

[0207] Synthesis of Resin (A-1) [ka] In a nitrogen atmosphere, 100.0 g of resin raw material (b-1), 3.85 g of V-601 (2,2'-azobis(isobutyric acid) dimethyl, manufactured by Wako Pure Chemical Industries, Ltd.), and 340 g of PGMEA (propylene glycol monomethyl ether acetate) were weighed in a 1 L graduated cylinder, and the mixture was degassed while stirring to prepare a monomer-polymerization initiator solution. 60 g of PGMEA was weighed in another 1 L flask in a nitrogen atmosphere, and the mixture was degassed while stirring, and then heated until the internal temperature reached 80°C. The monomer-polymerization initiator solution was added dropwise over 4 hours, and the polymerization liquid was stirred for 16 hours while maintaining the temperature at 80°C, and then cooled to room temperature. The obtained polymerization liquid was added dropwise to 5,000 g of vigorously stirred hexane, and the precipitated polymer was filtered off. The resulting polymer was washed twice with 600 g of hexane and then vacuum dried at 50° C. for 20 hours to obtain a white powdery resin (A-1). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-1): Mw = 8,500, Mw / Mn = 2.50

[0208] Synthesis of resin (A-2) [ka] In a nitrogen atmosphere, 188.2 g of resin raw material (b-2), 81.3 g of resin raw material (b-8), 9.0 g of oxalic acid, and 100 g of dioxane were added and reacted for 24 hours at an internal temperature of 100°C. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was collected, and the pressure was reduced to 2 mmHg at an internal temperature of 150°C to remove moisture, solvent, and residual monomers under reduced pressure, obtaining resin (A-2). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-2): Mw = 2,500, Mw / Mn = 2.87

[0209] Synthesis of resin (A-3) [ka] In a nitrogen atmosphere, 216.3 g of resin raw material (b-3), 81.3 g of resin raw material (b-8), 10.8 g of oxalic acid, and 200 g of dioxane were added and reacted for 24 hours at an internal temperature of 100°C. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was collected, and the pressure was reduced to 2 mmHg at an internal temperature of 150°C to remove moisture, solvent, and residual monomers under reduced pressure, obtaining resin (A-3). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-3): Mw = 3,300, Mw / Mn = 3.50

[0210] Synthesis of resin (A-4) [ka] In a nitrogen atmosphere, 144.2 g of resin raw material (b-4), 53.2 g of resin raw material (b-8), and 250 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 3.0 g of paratoluenesulfonic acid monohydrate and 7.1 g of PGME, which had been mixed and homogenized in advance, was slowly added dropwise, and the reaction was carried out at an internal temperature of 120°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was dried under reduced pressure to obtain resin (A-4). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-4): Mw = 2,900, Mw / Mn = 2.26

[0211] Synthesis of Resin (A-4') [ka] In a nitrogen atmosphere, 144.2 g of resin raw material (b-4), 95.8 g of resin raw material (b-8), and 250 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 3.0 g of paratoluenesulfonic acid monohydrate and 7.1 g of PGME, which had been mixed and homogenized in advance, was slowly added dropwise, and the reaction was carried out at an internal temperature of 120°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was dried under reduced pressure to obtain resin (A-4'). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-4'): Mw = 8,500, Mw / Mn = 2.65

[0212] Synthesis of resin (A-5) [ka] In a nitrogen atmosphere, 144.2 g of resin raw material (b-5), 40.6 g of resin raw material (b-8), and 250 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 3.0 g of paratoluenesulfonic acid monohydrate and 7.1 g of PGME, which had been mixed and homogenized in advance, was slowly added dropwise, and the reaction was carried out at an internal temperature of 120°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was then dried under reduced pressure to obtain resin (A-5). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-5): Mw = 3,300, Mw / Mn = 2.26

[0213] Synthesis of resin (A-6) [ka] In a nitrogen atmosphere, 160.2 g of resin raw material (b-6), 40.6 g of resin raw material (b-8), and 250 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 3.2 g of paratoluenesulfonic acid monohydrate and 8.0 g of PGME, which had been mixed and homogenized in advance, was slowly added dropwise, and the reaction was carried out at an internal temperature of 120°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was then dried under reduced pressure to obtain resin (A-6). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-6): Mw = 3,400, Mw / Mn = 2.54

[0214] Synthesis of resin (A-7) [ka] In a nitrogen atmosphere, 160.2 g of resin raw material (b-7), 40.6 g of resin raw material (b-8), and 300 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 3.2 g of paratoluenesulfonic acid monohydrate and 8.0 g of PGME, which had been mixed and homogenized in advance, was slowly added dropwise, and the reaction was carried out at an internal temperature of 120°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was dried under reduced pressure to obtain resin (A-7). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-7): Mw = 3,300, Mw / Mn = 2.41

[0215] Synthesis of resin (A-8) [ka] In a nitrogen atmosphere, 94.1 g of resin raw material (b-2), 89.8 g of resin raw material (b-9), and 400 g of dichloromethane were added to obtain a uniform dispersion at an internal temperature of 30°C. Then, 211 g of methanesulfonic acid was added over 2 hours, and the reaction was carried out at an internal temperature of 30°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water, and the organic layer was dried under reduced pressure. 300 g of THF was added to the residue to obtain a uniform solution, which was then crystallized in 2,000 g of hexane. The precipitated crystals were separated by filtration, washed twice with 500 g of hexane, and collected. The collected crystals were dried in a vacuum at 70°C to obtain resin (A-8). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-8): Mw = 6,300, Mw / Mn = 3.11

[0216] Synthesis of resins (X-1) to (X-12) and comparative resins (R-2), (R-3), (R-5), and (R-7)

[0217] [Synthesis Example 1] Synthesis of Resin (X-1) [ka] In a nitrogen atmosphere, 20.0 g of resin (A-1), 11.5 g of potassium carbonate, and 100 g of DMF were added to obtain a uniform dispersion at an internal temperature of 50°C. 10.2 g of modifying agent (c-1) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and then the separated aqueous layer was removed. The resulting organic layer was added to 1500 g of hexane, and the upper layer was removed. The resin was then dissolved again in 300 ml of methyl isobutyl ketone, washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and the organic layer was dried under reduced pressure to obtain resin (X-1). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (X-1): Mw = 9,000, Mw / Mn = 2.75

[0218] [Synthesis Examples 2 to 19] Synthesis of Resins (X-2) to (X-12) and Comparative Resins (R-2), (R-3), (R-5), and (R-7) Resins (X-2) to (X-12) and comparative resins (R-2), (R-3), (R-5), and (R-7) shown in Tables 1 to 3 were obtained as products under the same reaction conditions as in Synthesis Example 1, except that resins (A-1) to (A-8), modifying agents (c-1) to (c-3), and potassium carbonate were used in the amounts shown in Tables 1 to 3. The weight average molecular weight (Mw) and dispersity (Mw / Mn) of these resins were determined and are shown in Table 4. The values ​​for (R-1), (R-4), and (R-6) are also shown.

[0219] [Table 1]

[0220] [Table 2]

[0221] [Table 3]

[0222] [Synthesis Examples 20-21] Synthesis of Comparative Resins (R-8) and (R-9)

[0223] The following resin raw materials were used for the synthesis of comparative resins (R-8) and (R-9). Resin raw material: [ka]

[0224] [Synthesis Example 20] Synthesis of Comparative Resin (R-8) [ka] In a nitrogen atmosphere, 90.1 g of resin raw material (A-9), 9.7 g of resin raw material (b-8), and 270 g of 2-methoxy-1-propanol were added, and the mixture was made into a homogeneous solution at a liquid temperature of 80°C. Then, 18 g of a 20% solution of paratoluenesulfonic acid in 2-methoxy-1-propanol was slowly added, and the mixture was stirred at a liquid temperature of 110°C for 8 hours. After cooling to room temperature, 600 g of methyl isobutyl ketone was added, and the organic layer was washed five times with 200 g of pure water, and then the organic layer was dried under reduced pressure. 320 g of THF was added to the residue, and the polymer was reprecipitated with 1,350 g of hexane. The precipitated polymer was separated by filtration and dried under reduced pressure to obtain a comparative resin (R-8). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (R-8): Mw = 3,460, Mw / Mn = 4.60

[0225] [Synthesis Example 21] Synthesis of Comparative Resin (R-9) [ka] In a nitrogen atmosphere, 15.4 g of resin raw material (A-10), 13.6 g of resin raw material (A-11), 1.0 g of resin raw material (A-12) and 60 g of 2-methoxy-1-propanol were stirred at an internal temperature of 100 ° C. to obtain a homogeneous solution, and then 1.00 g of benzyltriethylammonium chloride was added and 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 that order. The organic layer was dried under reduced pressure to obtain a comparative resin (R-9). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (R-9): Mw = 910, Mw / Mn = 1.03

[0226] [Table 4]

[0227] Preparation of compositions for forming resist underlayer film (UL-1 to 14, Comparative Examples UL-1 to 11) Resins (X-1) to (X-12), (R-1) to (R-9), base generators (B-1) to (B-4), crosslinking agent (D-1), and flow promoter (E-1) were dissolved in an organic solvent containing 0.1 mass % of FC-4430 (manufactured by 3M Corporation, refined in-house) in the ratios shown in Tables 6 and 7, and the solution was filtered through a 0.1 μm fluorine resin filter to prepare compositions for forming resist underlayer films (UL-1 to 14, Comparative Examples UL-1 to 11).

[0228] [(B) Base generator] The base generators (B-1) to (B-4) used in the composition for forming a resist underlayer film are shown below. [ka]

[0229] [Crosslinking agent] The crosslinking agent (D-1) used in the composition for forming the resist underlayer film is shown below. [ka]

[0230] [Flow enhancer] The flowability promoter (E-1) used in the composition for forming the resist underlayer film is shown in Table 5 below. [Table 5]

[0231] [Table 6]

[0232] [Table 7]

[0233] [Solvent Resistance Evaluation and Film Thickness Uniformity Evaluation (Examples 1-1 to 1-14, Comparative Examples 1-1 to 1-11)] The resist underlayer film forming compositions (UL-1 to 14, Comparative Examples UL-1 to 11) prepared above were applied onto silicon substrates and baked at each baking temperature for 60 seconds, after which the film thickness from the center to the outer periphery of the substrate was measured to calculate the average film thickness (a [nm]). Next, PGMEA solvent was dispensed onto the substrate, left for 30 seconds, spin-dried, and baked at 100°C for 60 seconds to evaporate the PGMEA, and the film thickness (b [nm]) was measured. The film thickness difference before and after PGMEA treatment (residual film ratio: (b / a) x 100) was calculated. In addition, for the films fired under each condition, the film thickness was measured from the center to the outer periphery of the substrate, and the film thickness uniformity was evaluated as "A" (good) if the difference between the maximum and minimum film thicknesses was less than 3% of the average film thickness (a), "B" (fairly good) if it was 3% or more but less than 5%, and "C" (poor) if it was 5% or more. Furthermore, the film formability of the resist underlayer film prepared was observed with an optical microscope, and the film formability was evaluated as "good" if there were no defects such as cracks or wrinkles, and "poor" if cracks or wrinkles were observed. The results of Examples 1-1 to 1-14 are shown in Table 8 below, and the results of Comparative Examples 1-1 to 1-11 are shown in Table 9 below.

[0234] [Table 8]

[0235] [Table 9]

[0236] As shown in Table 8, Examples 1-1 to 1-14 using the resist underlayer film forming compositions UL-1 to 14 of the present invention exhibit good film formability and film thickness uniformity when forming a thick film. In addition, the remaining film rate ((b / a)×100) after PGMEA rinsing treatment was 99% or more, which indicates that a crosslinking reaction occurred and sufficient solvent resistance was exhibited. On the other hand, in the case of Comparative Examples 1-1, 1-4, and 1-6 using Comparative Examples UL-1, UL-4, and UL-6, which have phenolic hydroxyl modified groups outside the range of the present invention, deterioration in film thickness uniformity was observed, possibly due to high resin viscosity and insufficient fluidity during spin coating. It is presumed that Comparative Example 1-8 using Comparative Example UL-8 containing a resin (R-6) with a molecular weight of less than 3,000 had insufficient heat resistance of the low molecular weight component, resulting in a large amount of sublimate and further deterioration in film thickness uniformity. In Comparative Example 1-10 using Comparative Example UL-10 containing resin (R-8) having a rigid cardo structure, and Comparative Example 1-11 using Comparative Example UL-11 containing resin (R-9), cracks were observed on the surface of the resist underlayer film after baking the substrate. Also, deterioration of the film thickness uniformity was confirmed due to the presence of cracks. When forming a thick film of 3 μm or more, it can be said that it is preferable to use a resin containing any of styrene units, novolac type phenol units, and novolac type naphthol units.

[0237] [Embedding characteristics (Examples 2-1 to 2-14, Comparative Examples 2-1 to 2-9)] The resist underlayer film forming compositions (UL-1 to 14 and Comparative Examples UL-1 to 9) used in the solvent resistance evaluation were applied onto a SiO2 wafer substrate 7 having a dense hole pattern (hole diameter 0.45 μm, hole depth 11.0 μm, distance between the centers of two adjacent holes 1.00 μm) as shown in FIG. 2(G) (plan view) and (H) (cross-sectional view), respectively, and baked for 60 seconds at temperatures listed in Tables 8 and 9 to form a resist underlayer film 8 as shown in FIG. 2(I). The cross-sectional shape of each of the obtained wafer substrates was observed using a scanning electron microscope (SEM) to confirm whether there were no voids inside the holes, and whether there was no peeling at the interface between the pattern sidewalls and the resist underlayer film, and whether the resist underlayer film was filled in. The results are shown in Table 10. When a resist underlayer film forming composition with poor filling properties was used, voids were generated inside the holes in this evaluation. Furthermore, when a composition for forming a resist underlayer film with poor adhesion is used, peeling occurs on the pattern sidewall or at the interface between the substrate and the resist underlayer film in this evaluation. When a composition for forming a resist underlayer film with good filling properties and adhesion is used, the resist underlayer film 8 is filled in the hole without voids or peeling, as shown in FIG. 2(I).

[0238] [Table 10]

[0239] As shown in Table 10, Examples 2-1 to 2-14, which use UL-1 to 14, which are compositions for forming resist underlayer films of the present invention, are capable of filling hole patterns without voids or peeling, and are found to have excellent filling properties and adhesion. On the other hand, in Comparative Examples 2-1, 2-4, 2-6, and 2-8, which used Comparative Examples UL-1, UL-4, UL-6, and UL-8, it is believed that the large amount of hydroxyl groups in the resin caused insufficient fluidity, resulting in the generation of voids due to poor filling. In Comparative Examples 2-2 and 2-5, which used Comparative Examples UL-2 and UL-5, no voids were generated, but peeling due to insufficient adhesion was observed. This is presumably due to an insufficient amount of hydroxyl groups in the resin. In Comparative Example 2-7 using Comparative Example UL-7, no voids were generated, but peeling due to insufficient adhesion was observed. This is presumably because the composition does not contain a base generator, and therefore adhesion was not improved. Comparative Example 2-3, which used Comparative Example UL-3, is a composition containing a base generator, but it is presumed that the adhesion did not improve because the amount of hydroxyl groups in the resin was insufficient. In Comparative Example 2-9, which used Comparative Example UL-9, not only peeling from the substrate was observed, but also voids were observed. It is presumed that the occurrence of voids was due to the large molecular weight of the resin and insufficient thermal fluidity. From the viewpoint of film thickness uniformity and filling characteristics, it can be said that the molecular weight of the resin needs to be 3,000 to 10,000.

[0240] [Pattern Forming Method (Examples 3-1 to 3-12, 4-1 to 4-12, Comparative Examples 3-1 to 3-7)] The resist underlayer film forming compositions (UL-1 to 12 and Comparative Examples UL-1 to 7) were each applied onto a silicon wafer substrate on which an SiO2 film had been formed by HMDS treatment (90°C x 60 seconds), and baked in air at 250°C for 60 seconds to form a resist underlayer film with a thickness of 3,000 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 thickness of 45 nm, and an ArF single-layer resist of the resist upper layer film material was applied thereon and baked at 105°C for 60 seconds to form a photoresist film with a thickness of 100 nm.

[0241] Silicon-containing resist intermediate film material (SOG-1) was prepared by dissolving a polymer represented by ArF silicon-containing intermediate film polymer (SiP1) and a thermal crosslinking catalyst (CAT1) in an organic solvent containing 0.1 mass % of FC-4430 (manufactured by Sumitomo 3M) in the ratios shown in Table 11, and filtering the solution through a fluorine resin filter having a pore size of 0.1 μm.

[0242] [Table 11]

[0243] The structural formulae of the ArF silicon-containing intermediate film polymer (SiP1) and thermal crosslinking catalyst (CAT1) used are shown below. [ka]

[0244] The resist top layer film material (ArF single layer resist) was prepared by dissolving a polymer (RP1), an acid generator (PAG1), and a basic compound (Amine1) in a solvent containing 0.1 mass % of a surfactant FC-4430 (Sumitomo 3M Limited) in the ratios shown in Table 12, and filtering the solution through a 0.1 μm fluororesin filter.

[0245] [Table 12]

[0246] The polymer (RP1), acid generator (PAG1), and basic compound (Amine1) used in the resist top layer material (ArF single layer resist) are shown below. [ka]

[0247] Next, the resist was exposed using an ArF immersion exposure tool (Nikon Corporation; NSR-S610C, NA 0.85, σ 0.75, conventional, 6% halftone phase shift mask), baked at 100°C for 60 seconds (PEB), and developed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) to obtain a 5 μm, 1:1 positive line and space pattern (resist pattern).

[0248] Next, the resist intermediate film was etched by dry etching using a Tokyo Electron etching device Telius with the resist pattern as a mask to form a resist intermediate film pattern, and the resist underlayer film was etched using the resist intermediate film pattern as a mask to form a resist underlayer film pattern. The etching conditions are as shown below.

[0249] Transfer conditions of the resist pattern to the resist interlayer. Chamber pressure: 80mT RF power (top): 500W RF power (bottom): 300W CF4 gas flow rate: 150sccm CHF3 gas flow rate: 50sccm Time: 35sec

[0250] Transfer conditions of the resist intermediate film pattern to the resist underlayer film. Chamber pressure: 80mT RF power (top): 500W RF power (bottom): 300W CO2 gas flow rate: 320sccm N2 gas flow rate: 80sccm Time:900sec

[0251] The cross section of the pattern was observed using an electron microscope (S-4700) manufactured by Hitachi, Ltd. The results are shown in Table 13. [Table 13]

[0252] As shown in Table 13, in Examples 3-1 to 3-12 in which the resist underlayer film-forming compositions UL-1 to 12 of the present invention were used, the resist pattern was successfully transferred to the resist underlayer film in each case. In addition, no abnormality such as peeling was observed at the interface between the resist underlayer film and the substrate. On the other hand, in the above-mentioned embedding characteristic evaluation, in Comparative Examples 3-2, 3-3, 3-5, and 3-7, which used Comparative Examples UL-2, UL-3, UL-5, and UL-7, which were confirmed to have insufficient adhesion to the substrate, it was confirmed that gaps occurred at the interface between the resist underlayer film and the substrate after the dry etching treatment of the resist underlayer film. The cross-sectional shape of Example 3-10 is shown in FIG. 3(J), and the cross-sectional shape of Comparative Example 3-3 is shown in FIG. 3(K).

[0253] Next, the resist underlayer film was etched using the composition for forming the resist underlayer film (UL-1 to 12) of the present invention in the same manner as in the above evaluation, and the SiO2 film was then processed using the resist underlayer film as a mask.

[0254] Transfer conditions of resist underlayer film pattern onto SiO2 film. Chamber pressure: 10mT RF Power (Top): 100W RF power (bottom): 800W CF4 gas flow rate: 25sccm CHF3 gas flow rate: 15sccm O2 gas flow rate: 5sccm Time:900sec

[0255] The cross section of the pattern was observed using an electron microscope (S-4700) manufactured by Hitachi, Ltd. The results are shown in Table 14. [Table 14]

[0256] As shown in Table 14, in Examples 4-1 to 4-12 in which the resist underlayer film-forming compositions UL-1 to UL-12 of the present invention were used, the resist pattern was successfully transferred to the SiO2 film in all cases.

[0257] From the above, it has become clear that the composition for forming a resist underlayer film of the present invention has both high embedding properties and substrate adhesion, and is therefore extremely useful as a resist underlayer film material for use in a multilayer resist method, and that the pattern formation method of the present invention using this composition makes it possible to form a fine pattern with high precision even if the workpiece is a substrate having steps.

[0258] The present specification includes the following aspects. [1]: A composition for forming a resist underlayer film used in a multi-layer resist method, comprising (A) a resin, (B) a base generator, and (C) an organic solvent; The weight average molecular weight of the (A) resin is 3,000 to 10,000, the (A) resin is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying the phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying the phenolic hydroxyl group, A composition for forming a resist underlayer film, characterized in that, when a is a ratio of phenolic hydroxyl groups contained in the (A) resin and b is a ratio of groups modified with the phenolic hydroxyl groups, the composition satisfies the relationships a+b=1, 0.1≦a≦0.5, and 0.5≦b≦0.9. [2]: The composition for forming a resist underlayer film according to the above [1], wherein the (A) resin contains any one of a styrene unit, a novolac-type phenol unit, and a novolac-type naphthol unit. [3]: The composition for forming a resist underlayer film according to the above [1] or [2], wherein the (A) resin is a resin having a structural unit represented by the following general formula (1-1) or the following general formula (1-2): [ka] (In the above general formula (1-1), R 00 is a hydrogen atom or a methyl group, and R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R 02 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, 02In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationships a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 are satisfied. m1 is an integer of 0 to 4, n1 is an integer of 1 to 5, and m1+n1 is an integer of 1 or more and 5 or less. [ka] (In the general formula (1-2), R 01 is a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R 02 is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, 02 In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationships a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 are satisfied. X is a divalent organic group having 1 to 30 carbon atoms, p is 0 or 1, and when p is 0, m2 is an integer of 0 to 3, n2 is an integer of 1 to 4, and m2+n2 is an integer of 1 or more and 4 or less, and when p is 1, m2 is an integer of 0 to 5, n2 is an integer of 1 to 6, and m2+n2 is an integer of 1 or more and 6 or less.) [4]: In the general formulas (1-1) and (1-2), the R 02 is any one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a structure represented by the following general formula (8): [ka] (In the general formula (8), * represents a bonding site to an oxygen atom, and R A represents an optionally substituted divalent organic group having 1 to 10 carbon atoms; R B is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms. [5]: The composition for forming a resist underlayer film according to the above [3] or [4], wherein, in the general formula (1-2), p is 0. [6]: The composition for forming a resist underlayer film according to any one of the above [3] to [5], wherein in the general formula (1-1), n1 is 1. [7]: The composition for forming a resist underlayer film according to any one of the above [3] to [6], wherein in the general formula (1-2), n2 is 1. [8]: The composition for forming a resist underlayer film according to any one of [1] to [7] above, wherein a and b satisfy the relationships: a+b=1, 0.15≦a≦0.4, and 0.6≦b≦0.85. [9]: The composition for forming a resist underlayer film according to any one of [1] to [8] above, wherein the (B) base generator is a compound that exhibits basicity through thermal decomposition.

[10] : The composition for forming a resist underlayer film according to any one of [1] to [9] above, wherein the base generator (B) is any one of those represented by the following general formulas (2), (3) and (4): [ka] (In the above formula, R 01 ~R 03 each independently represents a linear, branched or cyclic alkyl group, alkenyl group or aralkyl group having 1 to 10 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. 01 , R 02 and R 03 Any two of X may be bonded to each other to form a ring together with the sulfur atom in the formula. - represents an organic or inorganic counterion. - OH - Does not include R 04 and R 05 are each independently an aryl group having 6 to 20 carbon atoms which may be substituted or interposed with a heteroatom, and some or all of the hydrogen atoms in the aryl group may be substituted with a linear, branched or cyclic alkyl or alkoxy group having 1 to 10 carbon atoms. 04 and R 05 may be bonded to each other to form a ring together with the iodine atom in the formula.06 , R 07 , R 08 and R 09 each independently represents a hydrogen atom, or a linear, branched or cyclic alkyl group or alkenyl group having 1 to 20 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aralkyl group having 7 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. 06 , R 07 , R 08 and R 09 Any two or more of may be bonded to each other to form a ring together with the nitrogen atom in the formula.

[11] : X in the general formulas (2), (3) and (4) - is a structure represented by any one of the following general formulas (5), (6), and (7), and is any one of anions selected from the group consisting of chloride ion, bromide ion, iodide ion, fluoride ion, cyanide ion, nitrate ion, and nitrite ion. [ka] (In the above formula, R 10 R represents an ether group, an ester group, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, 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. 11 R represents an aryl group having 6 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. 12 , R 13 , R 14each independently represents a hydrogen atom, a halogen atom other than a fluorine atom, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain an ether group, an ester group or a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, in which one or more hydrogen atoms may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. 12 , R 13 , R 14 Two or more of may be bonded to each other to form a ring.)

[12] : The composition for forming a resist underlayer film according to any one of [1] to

[11] above, characterized in that the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn of the (A) resin, as determined by a gel permeation chromatography method in terms of polystyrene, is 2.00≦Mw / Mn≦5.00.

[13] : The composition for forming a resist underlayer film according to any one of [1] to

[12] above, wherein the content of the (A) resin in the composition for forming a resist underlayer film is 20 mass% or more.

[14] : The composition for forming a resist underlayer film according to any one of [1] to

[13] above, characterized in that the composition for forming a resist underlayer film contains (D) a crosslinking agent.

[15] : The composition for forming a resist underlayer film according to any one of [1] to

[14] above, characterized in that the composition for forming a resist underlayer film contains (E) a flowability promoter, characterized in that the weight loss rate at temperatures from 30°C to 190°C is less than 30% and the weight loss rate at temperatures from 30°C to 350°C is 98% or more.

[16] : The composition for forming a resist underlayer film according to the above

[15] , wherein the (E) flowability promoter comprises one or more compounds selected from the following general formulas (i) to (iii): [ka] (In the formula, R 1 are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms.1 W is a phenylene group or a divalent group represented by the following general formula (i-1). 2 , W 3 is a single bond or a divalent group represented by the following general formula (i-2): 1 is an integer from 1 to 10, and n 1 is an integer between 0 and 5.) [ka] (In the formula, * indicates a bond position, and R 10 , R 11 , R 12 , R 13 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. 10 , W 11 Each of m is independently a single bond or a carbonyl group. 10 , m 11 is an integer from 0 to 10, and m 10 +m 11 ≧1.) [ka] (In the formula, * indicates the bond position.) [ka] (In the formula, R 2 are each independently a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms. 4 W is a divalent group represented by the following general formula (ii-1). 5 is a single bond or a divalent group represented by the following general formula (ii-2): 2 is an integer from 2 to 10, and n 3 is an integer between 0 and 5.) [ka] (In the formula, * indicates a bond position, and R 20 , R 21 , R 22 , R 23 is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms.20 , m 21 is an integer from 0 to 10, and m 20 +m 21 ≧1.) [ka] (In the formula, * indicates the bond position.) [ka] (In the formula, R 3 , R 4 R is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and may be bonded to each other to form a cyclic structure. 5 , R 6 is an organic group having 1 to 10 carbon atoms, R 5 is a group containing either an aromatic ring or a divalent group represented by the following general formula (iii-1): 6 , W 7 is a single bond or a divalent group represented by the following general formula (iii-2), and at least one of them is a divalent group represented by (iii-2). [ka] (In the formula, * indicates a bond position, and W 30 is an organic group having 1 to 4 carbon atoms. [ka] (In the formula, * indicates the bond position.)

[17] : The composition for forming a resist underlayer film according to any one of [1] to

[16] above, further comprising one or more of (F) a surfactant and (G) a plasticizer.

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

[17] onto a substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a photoresist material; (I-3) a step of forming a pattern on the resist upper layer film by pattern-exposing the resist upper layer film and then developing the resist upper layer film 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 pattern has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

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

[17] onto a substrate to be processed, followed by heat treatment to form a resist underlayer film; (II-2) forming a resist intermediate film on the resist underlayer film; (II-3) 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 pattern-exposing the resist upper layer film and then developing the resist upper layer film 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 on which the pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the resist intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

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

[17] onto a substrate to be processed, followed by heat treatment to form a resist underlayer 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 underlayer film; (III-3) forming an organic thin film on the inorganic hard mask intermediate film; (III-4) forming a resist top layer film on the organic thin film using a photoresist material; (III-5) a step of forming a pattern on the resist upper layer film by pattern-exposing the resist upper layer film and then developing the resist upper layer film with a developer; (III-6) a step of transferring a 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 has been formed as a mask; (III-7) a step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

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

[18] to

[20] above, wherein the resist underlayer film has a thickness of at least 2 μm.

[22] : The method for forming a pattern according to any one of the above

[18] to

[21] , characterized in that the resist underlayer film is formed by applying the composition for forming a resist underlayer film according to any one of the above [1] to

[17] once to a thickness of at least 2 μm.

[0259] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0260] 1...Substrate to be processed, 2...Layer to be processed, 2a... pattern (pattern formed on a processing layer), 3... resist underlayer film, 3a...resist underlayer film pattern, 4...silicon-containing resist intermediate film, 4a...silicon-containing resist intermediate film pattern, 5...resist upper layer film, 5a: resist upper layer film pattern; 6: exposed portion; 7...SiO2 wafer substrate having a dense hole pattern; 8...resist underlayer film;

Claims

1. A composition for forming a resist underlayer film used in a multi-layer resist method, comprising (A) a resin, (B) a base generator, and (C) an organic solvent, The weight average molecular weight of the (A) resin is 3,000 to 10,000, the resin (A) is (A-1) a resin containing a phenolic hydroxyl group and a group obtained by modifying the phenolic hydroxyl group, or (A-2) a mixture of a resin containing a phenolic hydroxyl group and a resin containing a group obtained by modifying the phenolic hydroxyl group, A composition for forming a resist underlayer film, characterized in that, when a is a ratio of phenolic hydroxyl groups contained in the (A) resin and b is a ratio of groups modified with the phenolic hydroxyl groups, the composition satisfies the relationships: a+b=1, 0.1≦a≦0.5, and 0.5≦b≦0.

9.

2. 2. The composition for forming a resist underlayer film according to claim 1, wherein the resin (A) contains any one of a styrene unit, a novolac-type phenol unit, and a novolac-type naphthol unit.

3. The composition for forming a resist underlayer film according to claim 1, wherein the resin (A) is a resin having a structural unit represented by the following general formula (1-1) or the following general formula (1-2): 【Chemistry 1】 (In the general formula (1-1), R ００ is a hydrogen atom or a methyl group, R ０１ represents a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R ０２ is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, ０２ In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationship of a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 is satisfied. １ is an integer from 0 to 4, n １ is an integer from 1 to 5, m １ +n １ is an integer between 1 and 5.) 【Chemistry 2】 (In the general formula (1-2), R ０１ represents a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms; R ０２ is a hydrogen atom or a saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms which may be substituted, ０２ In the structure constituting the formula (1), when the ratio of hydrogen atoms is a' and the ratio of monovalent organic groups is b', the relationship of a'+b'=1, 0.1≦a'≦0.5, and 0.5≦b'≦0.9 is satisfied. X is a divalent organic group having 1 to 30 carbon atoms, p is 0 or 1, and when p is 0, m ２ is an integer from 0 to 3, n ２ is an integer from 1 to 4, m ２ +n ２ is an integer of 1 to 4, and when p is 1, m ２ is an integer from 0 to 5, n ２ is an integer from 1 to 6, m ２ +n ２ is an integer between 1 and 6.)

4. In the general formulas (1-1) and (1-2), the R ０２ is any one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a structure represented by the following general formula (8): 【Chemistry 3】 (In the above general formula (8), * represents a bonding site to an oxygen atom, and R Ａ represents an optionally substituted divalent organic group having 1 to 10 carbon atoms; R Ｂ is a hydrogen atom or an optionally substituted monovalent organic group having 1 to 10 carbon atoms.

5. The composition for forming a resist underlayer film according to claim 3, wherein p is 0 in the general formula (1-2).

6. In the general formula (1-1), n １ The composition for forming a resist underlayer film according to claim 3 , wherein

7. In the general formula (1-2), n ２ The composition for forming a resist underlayer film according to claim 3 , wherein

8. 2. The composition for forming a resist underlayer film according to claim 1, wherein a and b satisfy the relationships: a+b=1, 0.15≦a≦0.4, and 0.6≦b≦0.

85.

9. 2. The composition for forming a resist underlayer film according to claim 1, wherein the base generator (B) is a compound that develops basicity by thermal decomposition.

10. 2. The composition for forming a resist underlayer film according to claim 1, wherein the base generator (B) is any one of those represented by the following general formulas (2), (3) and (4): 【Chemistry 4】 (In the above formula, R ０１ ~R ０３ each independently represents a linear, branched or cyclic alkyl group, alkenyl group or aralkyl group having 1 to 10 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. ０１ , R ０２ and R ０３ Any two of X may be bonded to each other to form a ring together with the sulfur atom in the formula. － represents an organic or inorganic anion serving as a counter ion. － OH － Does not include. ０４ and R ０５ are each independently an aryl group having 6 to 20 carbon atoms which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, and some or all of the hydrogen atoms in the aryl group may be substituted with a linear, branched or cyclic alkyl or alkoxy group having 1 to 10 carbon atoms. ０４ and R ０５ may be bonded to each other to form a ring together with the iodine atom in the formula. ０６ , R ０７ , R ０８ and R ０９ each independently represents a hydrogen atom, or a linear, branched or cyclic alkyl group, alkenyl group or aralkyl group having 1 to 20 carbon atoms which may be substituted with a heteroatom or may have a heteroatom interposed therebetween, or an aryl group having 6 to 18 carbon atoms which may be substituted with a heteroatom or may have a heteroatom interposed therebetween. ０６ , R ０７ , R ０８ and R ０９ Any two or more of may be bonded to each other to form a ring together with the nitrogen atom in the formula.)

11. In the general formulas (2), (3) and (4), X － is any one of a structure represented by any one of the following general formulas (5), (6), and (7), and an anion selected from the group consisting of a chloride ion, a bromide ion, an iodide ion, a fluoride ion, a cyanide ion, a nitrate ion, and a nitrite ion. 【Chemistry 5】 (In the above formula, R １０ R represents an ether group, an ester group, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, 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. １１ R represents an aryl group having 6 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. １２ , R １３ , R １４ each independently represents a hydrogen atom, a halogen atom other than a fluorine atom, or a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, which may contain an ether group, an ester group or a carbonyl group, an alkenyl group, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, in which one or more hydrogen atoms may be substituted with a halogen atom, a hydroxyl group, a carboxyl group, an amino group or a cyano group. １２ , R １３ , R １４ Two or more of may be bonded to each other to form a ring.

12. 2. The composition for forming a resist underlayer film according to claim 1, wherein the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn of the resin (A) in terms of polystyrene as determined by a gel permeation chromatography method is 2.00≦Mw / Mn≦5.

00.

13. 2. The composition for forming a resist underlayer film according to claim 1, wherein the content of the resin (A) in the composition for forming a resist underlayer film is 20% by mass or more.

14. 2. The composition for forming a resist underlayer film according to claim 1, further comprising (D) a crosslinking agent.

15. The composition for forming a resist underlayer film according to claim 1, further comprising (E) a flowability promoter, which is characterized in that the composition for forming a resist underlayer film has a weight loss rate of less than 30% at temperatures from 30° C. to 190° C. and a weight loss rate of 98% or more at temperatures from 30° C. to 350° C.

16. The composition for forming a resist underlayer film according to claim 15, wherein the flowability promoter (E) comprises one or more compounds selected from the following general formulas (i) to (iii): 【Chemistry 6】 (In the formula, R １ are each independently a hydrogen atom, a hydroxyl group, or an optionally substituted organic group having 1 to 10 carbon atoms. １ W is a phenylene group or a divalent group represented by the following general formula (i-1): ２ , W ３ is a single bond or a divalent group represented by the following general formula (i-2): １ is an integer from 1 to 10, n １ is an integer from 0 to 5. 【Chemistry 7】 (In the formula, * indicates a bond position, R １０ , R １１ , R １２ , R １３ is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. １０ , W １１ Each of m is independently a single bond or a carbonyl group. １０ , m １１ is an integer from 0 to 10, m １０ +m １１ ≧1.) 【Chemistry 8】 (In the formula, * indicates the bond position.) 【Chemistry 9】 (In the formula, R ２ are each independently a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms. ４ is a divalent group represented by the following general formula (ii-1): ５ is a single bond or a divalent group represented by the following general formula (ii-2): ２ is an integer from 2 to 10, and n ３ is an integer from 0 to 5. 【Chemistry 10】 (In the formula, * indicates a bond position, R ２０ , R ２１ , R ２２ , R ２３ is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms. ２０ , m ２１ is an integer from 0 to 10, m ２０ +m ２１ ≧1.) 【Chemistry 11】 (In the formula, * indicates the bond position.) 【Chemistry 12】 (In the formula, R ３ , R ４ R is a hydrogen atom, a hydroxyl group, or an organic group having 1 to 10 carbon atoms which may be substituted, and may be bonded to each other to form a ring structure. ５ , R ６ is an organic group having 1 to 10 carbon atoms, R ５ is a group containing either an aromatic ring or a divalent group represented by the following general formula (iii-1): ６ , W ７ is a single bond or a divalent group represented by the following general formula (iii-2), and at least one of them is a divalent group represented by (iii-2). 【Chemistry 13】 (In the formula, * indicates a bond position, W ３０ is an organic group having 1 to 4 carbon atoms. 【Chemistry 14】 (In the formula, * indicates the bond position.)

17. 2. The composition for forming a resist underlayer film according to claim 1, further comprising at least one of (F) a surfactant and (G) a plasticizer.

18. A method for forming a pattern on a workpiece substrate, comprising the steps of: (I-1) A step of applying the composition for forming a resist underlayer film according to any one of claims 1 to 17 onto a substrate to be processed, and then heat-treating the composition to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a photoresist material; (I-3) a step of pattern-exposing 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 has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

19. A method for forming a pattern on a workpiece substrate, comprising the steps of: (II-1) A step of applying the composition for forming a resist underlayer film according to any one of claims 1 to 17 onto a substrate to be processed, and then heat-treating the composition to form a resist underlayer film; (II-2) forming a resist intermediate film on the resist underlayer film; (II-3) 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 pattern-exposing the resist upper layer film and then developing the resist upper layer film with a developer; (II-5) a step of transferring a pattern to the resist intermediate film by dry etching using the resist upper layer film on which the pattern has been formed as a mask; (II-6) a step of transferring a pattern to the resist underlayer film by dry etching using the resist intermediate film to which the pattern has been 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 has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method comprising the steps of:

20. A method for forming a pattern on a workpiece substrate, comprising the steps of: (III-1) A step of forming a resist underlayer film by applying the composition for forming a resist underlayer film according to any one of claims 1 to 17 onto a substrate to be processed and then heat-treating the composition; (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 underlayer film; (III-3) forming an organic thin film on the inorganic hard mask intermediate film; (III-4) forming a resist top layer film on the organic thin film using a photoresist material; (III-5) a step of pattern-exposing the resist upper layer film and then developing the same with a developer to form a pattern on the resist upper layer film; (III-6) a step of transferring a 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 has been formed as a mask; (III-7) A step of transferring a pattern to the resist underlayer film by dry etching using the inorganic hard mask intermediate film to which the pattern has been 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 comprising the steps of:

21. 20. The pattern forming method according to claim 18, wherein the resist underlayer film has a thickness of at least 2 μm.

22. 20. The method for forming a pattern according to claim 18, wherein the resist underlayer film is formed by applying the composition for forming a resist underlayer film according to any one of claims 1 to 17 once to a thickness of at least 2 μm.

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