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

Abstract

To provide: a resist underlayer film material having excellent filling property and adhesiveness, and favorable planarizing property; and a patterning method and a method for forming a resist underlayer film each of which uses the resist underlayer film material.SOLUTION: The present invention provides a resist underlayer film material used in a multilayer resist process, the material containing: (A) a resin having a structural unit represented by the following general formula (1); and (B) an organic solvent. The resin content is 20 mass% or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resist underlayer film material, a pattern forming method, and a method for forming a resist underlayer film. [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 an intermediate film having a different etching selectivity from the photoresist film (i.e., resist top layer film) is interposed between the resist top layer film and the substrate to be processed, and after a pattern is obtained in the resist top layer film, the pattern is transferred to the intermediate film by dry etching using the resist top 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 intermediate 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, this material has a high amount of hydroxyl groups in the polymer structure, which reduces fluidity when embedded in a substrate having deep patterns used in cutting-edge processes, and there is a concern that voids may occur.

[0010] On the other hand, a material in which the hydroxyl groups contained in a novolac polymer are protected with a group containing a triple bond is known as a resist underlayer film material containing a compound having a structure in which the hydroxyl groups contained in the polymer are protected (Patent Document 3). However, this 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 resist underlayer film material having excellent filling properties, adhesion, and good planarization properties, a pattern formation method using the same, and a method for forming a resist underlayer film. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides a resist underlayer film material for use in a multi-layer resist method, the resist underlayer film material comprising (A) a resin having a structural unit represented by the following general formula (1) and (B) an organic solvent, the resin content being 20 mass % or more: [ka] (In the above general formula (1), R 01 is an optionally substituted 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, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1.

[0015] A resist underlayer film material containing such a structure can have excellent filling properties, adhesion, and good planarization properties, and by adjusting the ratio of the structure within the above range, it is possible to both eliminate voids and suppress peeling when filling a substrate to be processed. Furthermore, if the content of the resin is 20 mass% or more, a thick resist underlayer film can be formed in a single process.

[0016] In addition, in the general formula (1), 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 (2). [ka] (In the above general formula (2), * represents a bonding site to an oxygen atom, and R Ais 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.

[0017] A resist underlayer film material containing such a structure can have even better filling / planarization properties.

[0018] In this case, it is preferable that in the general formula (1), a and b satisfy the relationships a+b=1, 0.15≦a≦0.4, and 0.6≦b≦0.85.

[0019] By adjusting the proportion of the structure within such a range, it is possible to particularly effectively eliminate voids and suppress peeling when filling a substrate to be processed.

[0020] In this case, it is preferable that p is 0 in the general formula (1).

[0021] A resist underlayer film material containing such a structure can have particularly excellent filling properties.

[0022] In this case, it is preferable that n is 1 in the general formula (1).

[0023] A resist underlayer film material containing such a structure can have extremely excellent filling properties.

[0024] In this case, the weight average molecular weight of the (A) resin is preferably 3,000 to 10,000.

[0025] If the molecular weight is within this range, the resist underlayer film material containing this resin has good film-forming properties, and can suppress the generation of sublimates during heat curing, thereby suppressing contamination of the device due to the sublimates.Furthermore, the generation of coating defects can be suppressed, and the material can have even better filling / planarization properties.

[0026] In this case, the resist underlayer film material preferably contains a crosslinking agent (C).

[0027] In this case, it is preferable that the resist underlayer film composition further contains one or more of (D) an acid generator, (E) a surfactant, (F) a plasticizer, and (G) a dye.

[0028] In the resist underlayer film material 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.

[0029] 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 resist underlayer film composition described above onto the substrate to be processed, followed by heat treatment to form a resist underlayer film; (I-2) forming a resist upper layer film on the resist underlayer film using a 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:

[0030] The present invention also provides a method for forming a pattern on a workpiece substrate, comprising the steps of: (II-1) forming a resist underlayer film by applying the resist underlayer film composition described above onto the substrate to be processed and then subjecting the substrate to a heat treatment; (II-2) forming a silicon-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon-containing 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 silicon-containing 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 silicon-containing 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:

[0031] The present invention also provides a method for forming a pattern on a workpiece substrate, comprising the steps of: (III-1) forming a resist underlayer film by applying the resist underlayer film composition described above onto the substrate to be processed and then heat-treating the applied 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:

[0032] In this way, the resist underlayer film material of the present invention can be suitably used in various pattern formation methods such as a two-layer resist process, a three-layer resist process using a 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 the resist underlayer film can effectively reduce unevenness and steps on the processed substrate, making it suitable for photolithography of the resist upper layer film.

[0033] In the pattern formation method of the present invention, the substrate to be processed may be a substrate having a structure with an aspect ratio of 10 or more or a step.

[0034] The pattern formation method of the present invention uses the resist underlayer film material of the present invention, which can form a resist underlayer film having high filling / planarization properties, and is therefore particularly useful for microfabrication of a substrate having such a structure or step.

[0035] The present invention also provides a method for forming a resist underlayer film that functions as an organic embedding film used in a manufacturing process of a semiconductor device, comprising spin-coating the resist underlayer film material described above onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds to form a hardened film.

[0036] The present invention also provides 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 resist underlayer film material described above onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied in an atmosphere with an oxygen concentration of 1% or more and 21% or less to form a hardened film.

[0037] By using such a method, the crosslinking reaction during the formation of the resist underlayer film can be promoted, and mixing with the resist upper layer film can be more effectively suppressed. In addition, by appropriately adjusting the heat treatment temperature, time, and oxygen concentration within the above ranges, the resist underlayer film can have filling / planarization properties and curing properties suitable for the intended use.

[0038] The present invention also provides 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 resist underlayer film material described above onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied in an atmosphere with an oxygen concentration of less than 1%, thereby forming a hardened film.

[0039] This method is useful because it promotes the crosslinking reaction during the formation of the resist underlayer film and more effectively suppresses mixing with the resist toplayer film without causing deterioration of the substrate to be processed, even if the substrate contains a material that is unstable when heated in an oxygen atmosphere.

[0040] In this case, the substrate to be processed may be a substrate having a structure with an aspect ratio of 10 or more or a step.

[0041] The resist underlayer film forming method of the present invention uses the resist underlayer film material of the present invention, which can form a resist underlayer film having high filling / planarization properties, and is therefore particularly suitable for forming a resist underlayer film on a substrate having such a structure or step. Effect of the Invention

[0042] As described above, the resist underlayer film material, the pattern forming method, and the resist underlayer film 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, even on a substrate to be processed having a large aspect ratio and parts that are particularly difficult to fill, such as a 3D-NAND memory that is becoming increasingly highly stacked, a resist underlayer film can be formed with excellent filling characteristics without causing defects such as voids or peeling, and further has suitable flattening characteristics, etching characteristics, and optical characteristics, and a pattern forming method using the material and a method for forming a resist underlayer film can be provided. [Brief description of the drawings]

[0043] [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 an explanatory diagram of a method for evaluating flattening characteristics. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The present invention will be described in more detail below. 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 resist underlayer film material that has excellent filling characteristics, is capable of forming a resist underlayer film without causing defects such as voids or peeling, and has suitable planarization characteristics, even on a substrate to be processed that has a large aspect ratio and particularly difficult to fill portions, such as a 3D-NAND memory that is becoming increasingly highly stacked, and further has a demand for a pattern forming method using the material and a method for forming a resist underlayer film.

[0045] The present inventors have been searching for various resist underlayer film materials and pattern formation methods in order to realize a high level of filling by forming an underlayer film in multilayer lithography using a resist underlayer film, and preferably to simultaneously achieve a high level of planarization by forming an underlayer film and excellent film formability. As a result, they have found that a resist underlayer film material containing a resin with a specific structure as a main component and a pattern formation method are very effective, and have completed the present invention.

[0046] That is, the present invention relates to a resist underlayer film material for use in a multi-layer resist method, comprising (A) a resin having a structural unit represented by the following general formula (1) and (B) an organic solvent, in which the content of the resin is 20 mass % or more: [ka] (In the above general formula (1), R 01 is an optionally substituted 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, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1.

[0047] The present invention will be described in detail below, but the present invention is not limited thereto.

[0048] <Resist Underlayer Film Materials> The resist underlayer film material of the present invention is a resist underlayer film material used in the multilayer resist method as described above, which contains (A) a resin having a structural unit represented by the following general formula (1) and (B) an organic solvent, and the content of the resin is 20 mass % or more. [ka] (In the above general formula (1), R 01 is an optionally substituted 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, m is an integer of 0 to 5, n is an integer of 1 to 6, m+n is an integer of 1 or more and 6 or less, and p is 0 or 1.

[0049] [(A) Resin having a structural unit represented by general formula (1)] The resist underlayer film material of the present invention contains the resin represented by the above general formula (1), and thus has excellent fluidity and substrate affinity. By adjusting the structural ratio within the above range, it is possible to both eliminate voids and suppress peeling when filling a substrate to be processed. If the content of the resin is less than 20% by mass, a resist underlayer film with a large thickness cannot be formed. From this, it is considered that even on a substrate to be processed having a large aspect ratio and a portion that is particularly difficult to fill, a resist underlayer film can be formed with excellent filling characteristics and without defects such as voids or peeling.

[0050] In the above general formula (1), R 01Examples 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.

[0051] Above R 01 Examples 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.

[0052]

[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.

[0053] In order to achieve both good filling and planarization characteristics, the above R 01 The organic group represented by the formula (I) is preferably a methyl group.

[0054] In the above general formula (1), 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.

[0055] 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.

[0056] 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.

[0057] Examples of the organic group represented by X include groups represented by the following formulas. [ka] (In the above formula, * represents a bond.)

[0058] In order to achieve both good filling properties and good planarization properties, the organic group represented by X is preferably a methylene group.

[0059] In the above general formula (1), 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 structures include a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and any of the structures represented by the following general formula (2). [ka] (In the above general formula (2), * 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.

[0060] In the above general formula (2), R AExamples 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.

[0061] In the above general formula (2), 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.

[0062] 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 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.

[0063] 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.)

[0064] In the resin having the structural unit represented by the above general formula (1), specific examples of the structure represented by the proportion b include, but are not limited to, the following. [ka]

[0065] Furthermore, in the above general formula (1), 02 In the structure constituting the compound, when the ratio of hydrogen atoms is a and the ratio of monovalent organic groups is b, a and b satisfy the relationships of a+b=1, 0.1≦a≦0.5, and 0.5≦b≦0.9. The relationship between a and b is preferably a+b=1, 0.15≦a≦0.4, and 0.6≦b≦0.85. If the ratio of the structure is outside the above range, it is not possible to simultaneously eliminate voids and suppress peeling when filling a substrate to be processed having a large aspect ratio and particularly difficult to fill portions.

[0066] Furthermore, in the above general formula (1), p is 0 or 1, n is an integer from 1 to 6, and preferably p is 0 and n is 1. A resist underlayer film material containing such a structure exhibits extremely excellent filling properties even in a substrate to be processed having a large aspect ratio and a portion that is particularly difficult to fill, and enables filling without voids or peeling.

[0067] Furthermore, in the above general formula (1), m is an integer of 0 to 5, and m+n is an integer of 1 or more and 6 or less.

[0068] (A) The resin having the structural unit represented by the general formula (1) preferably has a weight average molecular weight of 3,000 to 10,000. The weight average molecular weight is based on a value measured by gel permeation chromatography (tetrahydrofuran solvent, polystyrene standard). (A) The resin having the structural unit represented by the general formula (1) preferably has a weight average molecular weight of 3,000 to 10,000, more preferably 4,000 to 9,500. If the weight average molecular weight is 3,000 or more, the film-forming property is not inferior, and the device is not contaminated due to an increase in sublimates during heat curing. On the other hand, if the weight average molecular weight is 10,000 or less, coating defects are not generated, and the flattening / embedding properties are not inferior due to deterioration of fluidity.

[0069] In the present invention, (A) the resin having the structural unit represented by the above general formula (1) may be used alone or in combination of two or more. Alternatively, a resin not containing the structural unit represented by the above general formula (1) may be used in combination. 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.

[0070] The resist underlayer film material of the present invention can further be blended with other compounds or polymers. The blending compound or blending polymer is mixed with a resin having a structural unit represented by the above general formula (1) 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.

[0071] 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, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-Butyl-5-methylphenol, pyrogallol, thymol, isothymol, 4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'dimethyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'diallyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'difluoro-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'diphenyl-4,4'-(9H-fluoren-9-ylidene)bisphenol, 2,2'dimethoxy-4,4'-(9H- fluoren-9-ylidene) bisphenol, 2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 3,3,3',3',4,4'-hexamethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 2,3,2',3'-tetrahydro-(1,1')-spirobiindene-5,5'-diol, 5,5'-dimethyl-3,3,3',3'-tetramethyl-2,3,2',3'-tetrahydro-(1,1')-spirobiindene-6,6'-diol, 1-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 thereof described in JP-A-2006-293298, novolac resins of adamantanephenol compounds described in JP-A-2006-285095, bisnaphthol compounds and novolac resins thereof described in JP-A-2010-122656, and fullerene resin compounds described in JP-A-2008-158002 can also be blended.

[0072] Furthermore, a phenol compound represented by the following general formula (2A) or (3A) may be blended. [ka] (In the formula, R is a single bond or an organic group having 1 to 50 carbon atoms, X' is a group represented by the following general formula (2B), and m2 is an integer satisfying 1≦m2≦5.) [ka] (In the formula, n3 is 0 or 1, n4 is 1 or 2, and X 4 is a group represented by the following general formula (2C), and n6 is 0, 1, or 2. [ka] (In the formula, R 11 is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the hydrogen atom on the benzene ring in the formula may be substituted with a methyl group or a methoxy group.

[0073] In general formula (2A), R is a single bond or an organic group having 1 to 50 carbon atoms, X' is a group represented by general formula (2B) above, and m2 is an integer satisfying 1≦m2≦5.

[0074] In the general formula (2B), n3 is 0 or 1, n4 is 1 or 2, and X 4 is a group represented by the above general formula (2C), and n6 is 0, 1, or 2.

[0075] In general formula (2C), R 11 is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the hydrogen atom on the benzene ring in the formula may be substituted with a methyl group or a methoxy group.

[0076] [ka] (In the formula, R 101 , R 102 , R 103 , R 104 are each independently a hydroxyl group, m100 is 1, 2, or 3, R 100represents a hydrogen atom or a hydroxyl group when m100 is 1, a single bond or a group represented by the following general formula (3B) when m100 is 2, and a group represented by the following general formula (3C) when m100 is 3, in which the hydrogen atom on the aromatic ring may be substituted with a methyl group, a methoxy group, a hydroxymethyl group, or a methoxymethyl group. m101 is 0 or 1, m102 is 1 or 2, m103 is 0 or 1, m104 is 1 or 2, and m105 is 0 or 1. When m101 is 0, n101 and n102 are integers that satisfy 0≦n101≦3, 0≦n102≦3, and 1≦n101+n102≦4, and when m101 is 1, n101, n102, n103, and n104 are integers that satisfy 0≦n101≦2, 0≦n102≦2, 0≦n103≦2, 0≦n104≦2, and 2≦n101+n102+n103+n104≦8. [ka] (In the formula, * indicates a bond position, and R 106 , R 107 is a hydrogen atom or an organic group having 1 to 24 carbon atoms, and R 106 and R 107 may be bonded to each other to form a ring structure together with the carbon atoms to which they are attached. [ka] (In the formula, * indicates a bond position, and R 108 is a hydrogen atom or an organic group having 1 to 15 carbon atoms.

[0077] In general formula (3A), R 101 , R 102 , R 103 , R 104 are each independently a hydroxyl group, m100 is 1, 2, or 3, R 100represents a hydrogen atom or a hydroxyl group when m100 is 1, a single bond or a group represented by the following general formula (3B) when m100 is 2, and a group represented by the following general formula (3C) when m100 is 3, in which the hydrogen atom on the aromatic ring may be substituted with a methyl group, a methoxy group, a hydroxymethyl group, or a methoxymethyl group. m101 is 0 or 1, m102 is 1 or 2, m103 is 0 or 1, m104 is 1 or 2, and m105 is 0 or 1. When m101 is 0, n101 and n102 are integers that satisfy 0≦n101≦3, 0≦n102≦3, and 1≦n101+n102≦4, and when m101 is 1, n101, n102, n103, and n104 are integers that satisfy 0≦n101≦2, 0≦n102≦2, 0≦n103≦2, 0≦n104≦2, and 2≦n101+n102+n103+n104≦8.

[0078] In formula (3B), * indicates a bond position, and R 106 , R 107 is a hydrogen atom or an organic group having 1 to 24 carbon atoms, and R 106 and R 107 may be bonded to each other to form a ring structure together with the carbon atoms to which they are attached.

[0079] In formula (3C), * indicates a bond position, and R 108 is a hydrogen atom or an organic group having 1 to 15 carbon atoms.

[0080] Examples of the compound represented by the general formula (2A) include the following compounds. Any hydrogen atom on the aromatic ring of the following compounds may be substituted with a methyl group, a methoxy group, a hydroxymethyl group, or a methoxymethyl group. [ka]

[0081] [ka]

[0082] Examples of the compound represented by the general formula (3A) include the following compounds. Any hydrogen atom on the aromatic ring of the following compounds may be substituted with a methyl group, a methoxy group, a hydroxymethyl group, or a methoxymethyl group. [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] The blending amount of the blending compound or blending polymer is preferably 5 to 100 parts by mass, and more preferably 5 to 50 parts by mass, per 100 parts by mass of (A) the resin having a structural unit represented by the general formula (1).

[0087] [(B) Organic solvent] The (B) organic solvent that can be used in the resist underlayer film material of the present invention is not particularly limited as long as it can dissolve (A) the resin having a structural unit represented by the general formula (1), and is preferably one that can also dissolve the (C) crosslinking agent, (D) acid generator, (E) surfactant, (F) plasticizer, and (G) dye, which will be described later.

[0088] 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.

[0089] The amount of the organic solvent to be added is desirably adjusted depending on the set film thickness of the resist underlayer film, but is usually within the range of 100 to 50,000 parts by mass per 100 parts by mass of the resin of the above general formula (1).

[0090] In addition, in the resist underlayer film material of the present invention, the (B) organic solvent may be used as a mixture of one or more organic solvents having a boiling point of less than 180 degrees and one or more organic solvents having a boiling point of 180 degrees or higher (hereinafter also referred to as "high boiling point solvents").

[0091] Specific examples of organic solvents having a boiling point of less than 180° C. include propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, and cyclohexanone.

[0092] The organic solvent having a boiling point of 180° C. or more is not particularly limited as long as it can dissolve each component of the resist underlayer film material of the present invention, and may be, for example, a hydrocarbon, an alcohol, a ketone, an ester, an ether, or a chlorine-based solvent. Specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,Examples of the diethyl ester include 6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, and dibutyl adipate. These may be used alone or in combination.

[0093] The organic solvent having a boiling point of 180° C. or more may be appropriately selected from the above-mentioned ones according to the temperature at which the resist underlayer film material of the present invention is heat-treated. The boiling point of the organic solvent having a boiling point of 180° C. or more is preferably 180° C. to 300° C., more preferably 200° C. to 300° C. If the boiling point is so low that the volatilization during baking (heat treatment) is not too fast, it is considered that sufficient thermal fluidity can be obtained during film formation, and a resist underlayer film having excellent filling / flattening properties can be formed. In addition, if the boiling point is so high that the solvent does not volatilize after baking and remains in the film, it does not adversely affect the film properties such as etching resistance.

[0094] When an organic solvent having a boiling point of 180° C. or more is used, the blending amount is preferably 1 to 30 parts by mass per 100 parts by mass of an organic solvent having a boiling point of less than 180° C. Such a blending amount is preferable because it is not too small to impart sufficient thermal fluidity during baking, nor is it too large to remain in the film and lead to deterioration of film properties such as etching resistance.

[0095] [(C) Crosslinking agent] In addition, a crosslinking agent (C) may be added to the resist underlayer film material of the present invention in order to enhance the curability and further suppress intermixing with the resist upper layer film. The crosslinking agent is not particularly limited, and various known crosslinking agents can be widely used. Examples include melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, and phenol-based crosslinking agents (e.g., methylol or alkoxymethyl-type crosslinking agents of polynuclear phenols). When a crosslinking agent is added, the amount of the crosslinking agent is preferably 1 to 50 parts by mass, more preferably 10 to 40 parts by mass, based on 100 parts by mass of the resin having the structural unit represented by the general formula (1).

[0096] 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. Specific examples of glycoluril crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy and / or hydroxy substituted products thereof, and partial self-condensates thereof. Specific examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and / or hydroxy-substituted products thereof, and partial self-condensates thereof. Specific examples of the urea-based crosslinking agent include dimethoxymethylated dimethoxyethyleneurea, its alkoxy and / or hydroxyl substituted derivatives, and partial self-condensates thereof. A specific example of the β-hydroxyalkylamide crosslinking agent is N,N,N',N'-tetra(2-hydroxyethyl)adipamide. Specific examples of the isocyanurate crosslinking agent include triglycidyl isocyanurate and triallyl isocyanurate. Specific examples of the aziridine crosslinking agent include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate]. Specific examples of the oxazoline crosslinking agent include 2,2'-isopropylidenebis(4-benzyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis-4,5-diphenyl-2-oxazoline, 2,2'-methylenebis-4-phenyl-2-oxazoline, 2,2'-methylenebis-4-tertbutyl-2-oxazoline, 2,2'-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyloxazoline copolymer. 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.

[0097] Specific examples of polynuclear phenol-based crosslinking agents include compounds represented by the following general formula (10). [ka] (In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R 2 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5.

[0098] 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. R 2 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 preferable.

[0099] Specific examples of the compound represented by the above general formula (10) include the following compounds. Among these, from the viewpoint of improving the curability and thickness uniformity of the resist underlayer film, hexamethoxymethylated products of triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred.

[0100] [ka] (In the formula, R 2 is the same as above)

[0101] [ka] (In the formula, R 2 is the same as above)

[0102] [(D) Acid generator] In the resist underlayer film material of the present invention, an acid generator (D) can be added to further promote the curing reaction. The acid generator may be one that generates an acid by thermal decomposition or one that generates an acid by light irradiation, and any of these may be added. Specifically, the materials described in paragraphs

[0061] to

[0085] of JP-A-2007-199653 may be added, but are not limited thereto.

[0103] The acid generators can be used alone or in combination of two or more. When an acid generator is added, the amount of the acid generator is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the resin having the structural unit represented by the general formula (1).

[0104] In order to obtain better filling properties, it is preferable not to add the acid generator.

[0105] [(E) Surfactant] A surfactant (E) can be added to the resist underlayer film material of the present invention in order to improve the coating property in spin coating. As the surfactant, for example, those described in

[0142] to

[0147] of JP-A-2009-269953 can be used. Examples include nonionic surfactants and fluorine-based surfactants. When a surfactant is added, the amount of the surfactant added is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 10 parts by mass, based on 100 parts by mass of the resin having the structural unit represented by the general formula (1).

[0106] [(F) Plasticizer] In addition, in order to further improve the planarization / filling properties, a plasticizer (F) can be added to the resist underlayer film material of the present invention. The plasticizer 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, and polymers such as polyethers, polyesters, and polyacetal polymers described in JP-A-2013-253227. When a plasticizer is added, the amount of the plasticizer is preferably 5 to 500 parts by mass, more preferably 10 to 200 parts by mass, based on 100 parts by mass of the resin having the structural unit represented by the general formula (1).

[0107] [(G)Dye] In addition, the resist underlayer film material of the present invention may contain a dye (G) in order to further improve the resolution during patterning in multilayer lithography. The dye is not particularly limited as long as it is a compound having a suitable absorption at the exposure wavelength, and various known compounds may be widely used. Examples include benzenes, naphthalenes, anthracenes, phenanthrenes, pyrenes, isocyanuric acids, and triazines. When a dye is added, the amount of the dye is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the resin having the structural unit represented by the general formula (1).

[0108] <Pattern formation method> The present invention also provides a method for forming a pattern on a workpiece substrate, comprising the steps of: (I-1) a step of forming a resist underlayer film by applying the resist underlayer film material onto the substrate to be processed and then heat-treating the applied 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. (two-layer resist process).

[0109] There is also provided a method for forming a pattern on a workpiece substrate, comprising the steps of: (II-1) forming a resist underlayer film by applying the resist underlayer film material onto the substrate to be processed and then heat-treating the applied resist underlayer film; (II-2) forming a silicon-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon-containing 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 silicon-containing 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 silicon-containing 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. (three-layer resist process).

[0110] Additionally, there is provided a method for forming a pattern on a processed substrate, comprising the steps of: (III-1) forming a resist underlayer film by applying the resist underlayer film material onto the substrate to be processed and then heat-treating the applied 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. (four-layer resist process).

[0111] The thickness of the resist underlayer film used in the present invention is appropriately selected, but is preferably 1,000 to 20,000 nm, particularly 1,500 to 15,000 nm. In the case of a resist underlayer film for a three-layer process, a silicon-containing resist intermediate film containing silicon or a silicon-free resist top layer film can be formed thereon. In the case of a resist underlayer film for a two-layer process, a silicon-containing resist top layer film or a silicon-free resist top layer film can be formed thereon.

[0112] The pattern forming method of the present invention is suitably used for multilayer resist processes such as a silicon-containing two-layer resist process, a three-layer resist process using a silicon-containing resist intermediate film, a four-layer resist process using an inorganic hard mask intermediate film and an organic thin film, and a silicon-free two-layer resist process.

[0113] [3-layer resist process] The pattern forming method of the present invention will be described below with a three-layer resist process as an example, but is not limited to this process.In this case, the resist underlayer film is formed on a substrate using the above-mentioned resist underlayer film material, the silicon-containing resist intermediate film is formed on the resist underlayer film using the silicon-containing resist intermediate film material containing silicon atoms, the resist upper layer film is formed on the silicon-containing resist intermediate film using the resist upper layer film material of the photoresist composition to form a multi-layer resist film, the pattern circuit area of ​​the resist upper layer film is exposed, and then developed with a developer to form a resist pattern on the resist upper layer film, the resist upper layer film with the pattern formed is used as a mask to etch the silicon-containing resist intermediate film, the silicon-containing resist intermediate film with the pattern formed is used as a mask to etch the resist underlayer film, and the resist underlayer film with the pattern formed is used as a mask to process the substrate to form a pattern on the substrate.

[0114] Since a silicon-containing resist intermediate film containing silicon atoms exhibits resistance to etching by oxygen gas or hydrogen gas, as described above, the etching of the resist underlayer film is preferably carried out using the silicon-containing resist intermediate film as a mask with an etching gas mainly composed of oxygen gas or hydrogen gas.

[0115] In addition, in the pattern formation method of the present invention, at least a resist underlayer film is formed on a substrate using the resist underlayer film material, an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the resist underlayer film, a resist upperlayer film is formed on the inorganic hard mask intermediate film using a resist upperlayer film material consisting of a photoresist composition, a pattern circuit region of the resist upperlayer film is exposed to light and then developed with a developer to form a resist pattern on the resist upperlayer film, the inorganic hard mask intermediate film is etched using the obtained resist pattern as an etching mask, the resist underlayer film is etched using the obtained inorganic hard mask intermediate film pattern as an etching mask, and the substrate is processed using the obtained resist underlayer film pattern as a mask to form a pattern on the substrate.

[0116] As described above, when an inorganic hard mask intermediate layer is formed on a resist underlayer film, a silicon oxide film, a silicon nitride film, or a silicon oxide nitride film (SiON film) is formed by a CVD method, an ALD method, or the like. Methods for forming nitride films are described in JP-A-2002-334869 and WO2004 / 066377. The thickness of the inorganic hard mask is 5 to 3,000 nm, preferably 10 to 2,000 nm, and among them, a SiON film, which has a high effect as an anti-reflection film, is most preferably used for ArF exposure applications.

[0117] As the silicon-containing resist intermediate film in the three-layer resist process, a polysilsesquioxane-based intermediate film can be suitably used. The polysilsesquioxane-based intermediate film can easily be made to have an anti-reflection effect in excimer exposure, which can suppress reflected light during pattern exposure of the resist upper layer film, and has the advantage of excellent resolution. In particular, for 193 nm exposure, if a material containing a large amount of aromatic groups is used as the resist underlayer film, the k value becomes high and the substrate reflection becomes high, but the reflection can be suppressed with the silicon-containing resist intermediate film to reduce the substrate reflection 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 polysilsesquioxane is preferably used for 193 nm exposure, which is pendant with a light-absorbing group having a phenyl group or a silicon-silicon bond and crosslinked with acid or heat.

[0118] In this case, forming the silicon-containing resist intermediate film by spin coating is easier and more cost-effective than forming it by CVD.

[0119] The resist upper layer film in the three-layer resist film may be either positive or negative, and may be the same as the photoresist composition that is commonly used. When forming the resist upper layer film using the photoresist composition, a spin coating method is preferably used, as in the case of forming the resist underlayer film. After spin coating the photoresist composition, pre-baking is performed, preferably at 60 to 180°C for 10 to 300 seconds. Thereafter, exposure 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 upper layer film is not particularly limited, but is preferably 10 to 500 nm, particularly preferably 20 to 400 nm.

[0120] 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.

[0121] Next, the obtained resist pattern is used as a mask to perform etching. In the three-layer process, the silicon-containing resist intermediate film is etched using a fluorocarbon-based gas, with the resist pattern as a mask. Then, the silicon-containing resist intermediate film is used as a mask to perform etching of the resist underlayer film using oxygen gas or hydrogen gas.

[0122] The next step, etching of the substrate to be processed, can also be done by standard methods; for example, if the substrate is SiO2, SiN, or a silica-based low dielectric constant insulating film, etching is done mainly with fluorocarbon gases, while for p-Si, Al, or W, etching is done mainly with chlorine- or bromine-based gases. If the substrate is etched with fluorocarbon gases, the silicon-containing resist intermediate film of the three-layer process is stripped at the same time as the substrate is processed. If the substrate is etched with chlorine- or bromine-based gases, the silicon-containing resist intermediate film must be stripped separately after substrate processing by dry etching stripping with fluorocarbon gases or the like.

[0123] The substrate to be processed has a layer to be processed formed on it. The substrate is not particularly limited, and may be made of a material different from the layer to be processed, such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, or Al. The layer to be processed may be made of various low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, TiN, W-Si, Al, Cu, or Al-Si, and their stopper films, and is usually formed to a thickness of 50 to 15,000 nm, particularly 100 to 10,000 nm.

[0124] The pattern formation method of the present invention is also suitable for processing a stepped substrate, using as the processed substrate a substrate having a structure or steps with an aspect ratio of 10 or more. By forming the resist underlayer film of the present invention on a stepped substrate and carrying out burying and planarization, it becomes possible to uniform the film thicknesses of the silicon-containing resist intermediate film and resist top layer film that are subsequently formed, which is highly preferable since it becomes easy to ensure the exposure depth margin (DOF) during photolithography.

[0125] An example of a three-layer resist process is specifically shown below with reference to Figure 1. In the three-layer resist process, as shown in Figure 1(A), a resist underlayer film 3 is formed on a processable layer 2 laminated on a substrate 1, and then a silicon-containing resist intermediate film 4 is formed on top of that, and a resist upper layer film 5 is formed thereon.

[0126] Next, as shown in FIG. 1(B), the exposed portion 6 of the resist top layer film is exposed, and PEB (post-exposure bake) and development are performed to form a resist top layer film pattern 5a (FIG. 1(C)). Using the obtained resist top layer film pattern 5a as a mask, the silicon-containing resist intermediate film 4 is etched using a CF-based gas to form a silicon-containing resist intermediate film pattern 4a (FIG. 1(D)). After removing the resist top layer film pattern 5a, the resist underlayer film 3 is etched with oxygen-based or hydrogen-based plasma using the obtained silicon-containing resist intermediate film pattern 4a as a mask to form a resist underlayer film pattern 3a (FIG. 1(E)). Furthermore, after removing the silicon-containing resist intermediate film pattern 4a, the processed layer 2 is etched using the resist underlayer film pattern 3a as a mask to form a pattern 2a to be formed on the substrate (FIG. 1(F)).

[0127] When an inorganic hard mask intermediate film is used, the silicon-containing resist intermediate film 4 is the inorganic hard mask intermediate film, and when an organic thin film is laid, an organic thin film layer is provided between the silicon-containing resist intermediate film 4 and the resist upper layer film 5. The etching of the organic thin film may be performed consecutively prior to the etching of the silicon-containing resist intermediate film 4, or the etching of the silicon-containing resist intermediate film 4 may be performed by changing the etching device after etching only the organic thin film.

[0128] [4-layer resist process] The present invention can also be suitably used in a four-layer resist process using an organic thin film. In this case, at least a resist underlayer film is formed on a substrate using the resist underlayer film material, an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the resist underlayer film, an organic thin film is formed on the inorganic hard mask intermediate film, and a resist upperlayer film is formed on the organic thin film using a resist upperlayer film material consisting of a photoresist composition. A pattern circuit region of the resist upperlayer film is exposed to light, and then developed with a developer to form a resist upperlayer film pattern on the resist upperlayer film. The organic thin film and the inorganic hard mask intermediate film are etched using the obtained resist upperlayer film pattern as an etching mask, the resist underlayer film is etched using the obtained inorganic hard mask intermediate film pattern as an etching mask, and the substrate is processed using the obtained resist underlayer film pattern as a mask to form a pattern on the substrate.

[0129] A photoresist film may be formed on the inorganic hard mask intermediate film as a resist upper layer film, or as described above, an organic thin film may be formed on the inorganic hard mask intermediate film by spin coating, and a photoresist film may be formed on the organic thin film. When a SiON film is used as the inorganic hard mask intermediate film and an organic anti-reflective coating (BARC) having an absorbing group at the exposure wavelength is used as the organic thin film, it is possible to suppress reflection even in immersion exposure with a high NA exceeding 1.0 in excimer exposure by using two layers of anti-reflective coatings, a SiON film and an organic thin film. Another advantage of forming an organic thin film is that it has the effect of reducing the tailing of the photoresist pattern directly above the SiON. Another advantage is that when an adhesion film (ADL) having excellent affinity with the upper photoresist is used as the organic thin film, the pattern collapse of the photoresist can be suppressed.

[0130] <Method for forming resist underlayer film> The present invention provides a method for forming a resist underlayer film that functions as an organic embedding film used in the manufacturing process of a semiconductor device, comprising spin-coating the resist underlayer film material described above onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds to form a hardened film.

[0131] The present invention also provides a method for forming a resist underlayer film that functions as an organic embedded film used in the manufacturing process of a semiconductor device, comprising spin-coating the resist underlayer film material described above onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied in an atmosphere with an oxygen concentration of 1% or more and 21% or less to form a hardened film.

[0132] Alternatively, there is provided a method for forming a resist underlayer film that functions as an organic embedded film used in the manufacturing process of a semiconductor device, comprising spin-coating the resist underlayer film material described above onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied in an atmosphere with an oxygen concentration of less than 1%, thereby forming a hardened film.

[0133] In the method for forming the resist underlayer film of the present invention, the resist underlayer film material is coated on the 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 the 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 for 10 seconds to 600 seconds, more preferably 10 to 300 seconds. By appropriately adjusting the baking temperature and time within the above range, flattening, embedding properties, and hardening properties suitable for the application can be obtained. At a baking temperature of 100°C or higher, hardening proceeds sufficiently and mixing with the resist top layer film or the silicon-containing resist intermediate film does not occur. If the baking temperature is 600°C or lower, the thermal decomposition of the base resin can be suppressed, the film thickness does not decrease, and the film surface becomes uniform.

[0134] 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%.

[0135] In addition, the method for forming a resist underlayer film of the present invention preferably uses, as the substrate to be processed, a substrate having a structure or steps with an aspect ratio of 10 or more. The method for forming a resist underlayer film of the present invention is particularly useful when forming a planarizing organic film without voids on a substrate having a structure or steps with an aspect ratio of 10 or more. EXAMPLES

[0136] 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.

[0137] Resins (X-1) to (X-16) for resist underlayer film materials and resins (R-2) to (R-4) for comparative examples were synthesized by synthesizing intermediate resins (A-1) to (A-6) using resin raw materials (B-1) to (B-6) shown below, and controlling the reaction rate using modifying agents (C-1) to (C-3). Resin (R-1) for comparative examples was made by using resin (A-3) as the comparative resin (R-1). Resin raw material (B-6) was used as a raw material using a 37% aqueous solution.

[0138] Resin raw material: [ka]

[0139] Resins used as intermediates: [ka]

[0140] Modifiers: [ka]

[0141] The above-described resins (A-1) to (A-6) were synthesized as follows.

[0142] (Synthesis example A-1) Synthesis of Resin (A-1) [ka] In a nitrogen atmosphere, 188.2 g of resin raw material (B-1), 113.6 g of resin raw material (B-5), 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, thereby obtaining 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 = 6,500, Mw / Mn = 2.87

[0143] (Synthesis example A-2) Synthesis of resin (A-2) [ka] In a nitrogen atmosphere, 94.1 g of resin raw material (B-1), 89.8 g of resin raw material (B-6), 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-2). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-2): Mw = 6,300, Mw / Mn = 3.11

[0144] (Synthesis example A-3) Synthesis of resin (A-3) [ka] In a nitrogen atmosphere, 216.3 g of resin raw material (B-2), 113.6 g of resin raw material (B-5), 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, to obtain 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 = 7,000, Mw / Mn = 3.50

[0145] (Synthesis example A-4) Synthesis of resin (A-4) [ka] In a nitrogen atmosphere, 108.2 g of resin raw material (B-2), 89.8 g of resin raw material (B-6), 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 vacuum dried at 70°C 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 = 6,900, Mw / Mn = 3.34

[0146] (Synthesis example A-5) Synthesis of resin (A-5) [ka] In a nitrogen atmosphere, 144.2 g of resin raw material (B-3), 56.8 g of resin raw material (B-5), and 300 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 7.1 g of paratoluenesulfonic acid monohydrate and 7.1 g of PGME, which had been mixed and homogenized in advance, was slowly dropped and reacted at an internal temperature of 100°C for 8 hours. After the reaction was completed, it 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 make a homogenous solution, and then it was 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-5). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-5): Mw = 2,900, Mw / Mn = 2.26

[0147] (Synthesis example A-6) Synthesis of resin (A-6) [ka] In a nitrogen atmosphere, 160.2 g of resin raw material (B-4), 56.8 g of resin raw material (B-5), and 300 g of PGME (propylene glycol monomethyl ether) were added and homogenized at an internal temperature of 100°C. Then, a mixture of 8.0 g of paratoluenesulfonic acid monohydrate and 8.0 g of PGME, which had been mixed and homogenized in advance, was slowly dropped and reacted at an internal temperature of 80°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, and the organic layer was dried under reduced pressure. 300 g of THF was added to the residue to make a homogenous solution, and 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-6). The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the results were as follows: (A-6): Mw = 3,300, Mw / Mn = 2.54

[0148] Synthesis of Resins (X-1) to (X-16) and Comparative Resins (R-2) to (R-4)

[0149] [Synthesis Example 1] Synthesis of Resin (X-1) [ka] Under a nitrogen atmosphere, 20.0 g of resin (A-1), 31.3 g of potassium carbonate, and 100 g of DMF were added to obtain a uniform dispersion at an internal temperature of 50°C. 16.2 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 organic layer was further 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 = 8,200, Mw / Mn = 2.93

[0150] [Synthesis Examples 2 to 20] Synthesis of Resins (X-2) to (X-16) and Comparative Resins (R-2) to (R-4) Resins (X-2) to (X-16) and comparative resins (R-2) to (R-4) 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-6), 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. (X-1) and (R-1) are also shown.

[0151] [Table 1]

[0152] [Table 2]

[0153] [Table 3]

[0154] [Table 4]

[0155] Preparation of resist underlayer film materials (UL-1 to 18, comparative UL-1 to 4) Resins (X-1) to (X-16), (R-1) to (R-4), and crosslinker (C1) 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 the table below, and the solution was filtered through a 0.1 μm fluororesin filter to prepare resist underlayer film materials (UL-1 to 18, comparative UL-1 to 4).

[0156] [Table 5] PGMEA: Propylene glycol monomethyl ether acetate

[0157] [Table 6] PGMEA: Propylene glycol monomethyl ether acetate

[0158] In Table 6, the details of the crosslinking agent (C1) are as follows. [ka]

[0159] Solvent Resistance Measurement (Examples 1-1 to 1-18, Comparative Examples 1-1 to 1-4) The resist underlayer film materials (UL-1 to 18, comparative UL-1 to 4) prepared above were applied onto silicon substrates and baked for 60 seconds at the temperatures listed in the table below, after which the film thickness was measured, 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 solvent, the film thickness was measured again, and the difference in film thickness before and after PGMEA treatment was calculated to evaluate the solvent resistance. The results are shown in the table below.

[0160] [Table 7]

[0161] It can be seen that in the pattern formation method of the present invention, all resist underlayer film materials have good film-forming properties, are hardly thinned by solvent treatment, and provide films with good solvent resistance.

[0162] Filling characteristic evaluation (Examples 2-1 to 2-18, Comparative Examples 2-1 to 2-4) The above resist underlayer film materials were each applied onto a SiO2 wafer substrate 7 having a dense hole pattern (hole diameter 0.16 μm, hole depth 2.0 μm, distance between the centers of two adjacent holes 0.40 μm) and baked for 60 seconds at the temperature shown in the table below to form a resist underlayer film 8. The substrate used was a SiO2 wafer substrate having a dense hole pattern as shown in Figure 2 (G) (bird's-eye view) and (H) (cross-sectional view). The cross-sectional shape of each obtained wafer substrate was observed using a scanning electron microscope (SEM) to confirm whether there were no voids inside the holes, no peeling at the interface between the pattern sidewalls and the resist underlayer film material, and whether the holes were filled with the resist underlayer film. The results are shown in the table below. When a resist underlayer film material with poor filling properties was used, voids were generated inside the holes in this evaluation. Furthermore, when a resist underlayer film material with poor adhesion was used, peeling occurred at the interface between the pattern sidewalls and the resist underlayer film material in this evaluation. When a resist underlayer film material with good filling properties and adhesion is used, in this evaluation, the resist underlayer film is filled into the hole without any voids or peeling, as shown in FIG. 2(I).

[0163] [Table 8]

[0164] From the above results, it can be seen that the resist underlayer film materials of the examples (UL-1 to 18) can fill hole patterns without voids or peeling, and have excellent filling properties and adhesion. On the other hand, in the resist underlayer film materials of the comparative examples (Comparative UL-1 and Comparative UL-4), it is believed that voids occurred due to poor filling because of insufficient fluidity caused by a large amount of hydroxyl groups in the resin. In addition, in the resist underlayer film materials of the comparative examples (Comparative UL-2 and Comparative UL-3), although no voids occurred, it is believed that peeling occurred due to insufficient adhesion because the modification rate of hydroxyl groups was too high, resulting in an insufficient amount of hydroxyl groups in the resin.

[0165] Planarization characteristic evaluation (Examples 3-1 to 3-18, Comparative Example 3-1) The resist underlayer film materials were each diluted with PGMEA to a film thickness of 0.2 μm, then coated onto a SiO2 wafer substrate 9 having a giant isolated trench pattern (Figure 3(J), trench width 10 μm, trench depth 0.1 μm) and baked under the conditions shown in the table below to form a resist underlayer film 10. The difference in film thickness between the trench and non-trench parts of the resist underlayer film (delta 10 in Figure 3(K)) was then observed using a scanning electron microscope (SEM). The results are shown in the table below. In this evaluation, the smaller the difference in film thickness, the better the planarization characteristics.

[0166] [Table 9]

[0167] From the above results, it can be seen that the resist underlayer film materials of the examples (UL-1 to 18) have a smaller difference in film thickness between the trench portion and the non-trench portion of the resist underlayer film compared to the resist underlayer film material of the comparative example (Comparative UL-1), and are excellent in planarization characteristics. It is considered that the resist underlayer film material of the comparative example (Comparative UL-1), which has a low modification rate of hydroxyl groups, has a deteriorated thermal fluidity, and therefore the planarization characteristics are deteriorated. On the other hand, a high modification rate of hydroxyl groups is preferable for improving the planarization characteristics, but as mentioned above, if the modification rate is too high, there is a concern that peeling from the substrate to be processed may occur. With the present invention, by appropriately controlling the modification rate of hydroxyl groups, it is possible to achieve both good planarization characteristics and embedding characteristics.

[0168] Evaluation of in-plane uniformity of film thickness (Examples 4-1 to 4-18, Comparative Examples 4-1 to 4-4) The above resist underlayer film materials were each coated on a silicon substrate at three levels of evaluation film thickness: evaluation film thickness 1 (1000 nm), evaluation film thickness 2 (1500 nm), and evaluation film thickness 3 (3000 nm), and baked at 250°C for 60 seconds. After that, the film thickness was measured over the entire wafer, and the maximum, minimum, and average film thickness values ​​were calculated to evaluate the film thickness uniformity across the wafer. When the difference in film thickness (maximum - minimum) was divided by the average film thickness, it was evaluated as "A" (very good) if it was less than 2%, "B" (good) if it was 2% or more but less than 5%, and "C" (poor) if it was 5% or more. The results are shown in the table below.

[0169] [Table 10]

[0170] From the above results, it can be seen that the resist underlayer film materials of the examples (UL-1 to 18) have excellent in-plane thickness uniformity. In the resist underlayer film materials of the comparative examples (Comparative UL-1 and Comparative UL-4) with a low hydroxyl group modification rate, the in-plane thickness uniformity tended to deteriorate as the evaluated film thickness increased, possibly due to a decrease in fluidity, but the resist underlayer film materials of the examples (UL-1 to 14, 17, 18) with appropriately controlled modification rates showed stable and excellent in-plane thickness uniformity at all evaluated film thicknesses.

[0171] As described above, the resist underlayer film material, pattern formation method, and resist underlayer film formation method of the present invention can be suitably used in a multilayer resist process for fine patterning in semiconductor device manufacturing, and are particularly applicable to a multilayer resist process using a processed substrate having a large aspect ratio and portions that are particularly difficult to fill, such as 3D-NAND memories that are becoming increasingly highly stacked, and are therefore extremely useful industrially.

[0172] 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]

[0173] 1...substrate; 2...processed layer; 2a...pattern formed on substrate; 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; 9...SiO2 wafer substrate having a giant isolated trench pattern; 10...resist underlayer film, Delta 10: Difference in thickness between the resist underlayer film in the trench area and the non-trench area.

Claims

1. A resist underlayer film material used in a multilayer resist method, comprising: (A) a resin having a structural unit represented by the following general formula (1); and (B) an organic solvent, wherein the content of the resin is 20 mass % or more: 【Chemistry 1】 (In the above general formula (1), R ０１ is an optionally substituted saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms, 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 (2), 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, 0.2≦a≦0.5, and 0.5≦b≦0.8 are satisfied. X is a divalent organic group having 1 to 30 carbon atoms, m is an integer of 0 to 3, n is an integer of 1 to 4, m+n is an integer of 1 or more and 4 or less, and p is 0. 【Chemistry 2】 (In the above general formula (2), * represents a bonding site to an oxygen atom, R A is a divalent organic group having 1 to 10 carbon atoms which may be substituted, and R B is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms which may be substituted.)

2. 2. The resist underlayer film material according to claim 1, wherein in the general formula (1), a and b satisfy the relationships a+b=1, 0.2≦a≦0.4, and 0.6≦b≦0.

8.

3. 3. The resist underlayer film material according to claim 1, wherein n is 1 in the general formula (1).

4. 4. The resist underlayer film material according to claim 1, wherein the weight average molecular weight of the resin (A) is 3,000 to 10,000.

5. The resist underlayer film material according to claim 1 , further comprising (C) a crosslinking agent.

6. 6. The resist underlayer film material according to claim 1, further comprising at least one of (D) an acid generator, (E) a surfactant, (F) a plasticizer, and (G) a dye.

7. A method for forming a pattern on a workpiece substrate, comprising the steps of: (I-1) a step of forming a resist underlayer film by applying a resist underlayer film composition according to any one of claims 1 to 6 onto the substrate to be processed and then heat-treating the applied 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:

8. A method for forming a pattern on a workpiece substrate, comprising the steps of: (II-1) A step of forming a resist underlayer film by applying a resist underlayer film composition according to any one of claims 1 to 6 onto the substrate to be processed and then heat-treating the applied resist underlayer film; (II-2) forming a silicon-containing resist intermediate film on the resist underlayer film; (II-3) forming a resist upper layer film on the silicon-containing 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 silicon-containing 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 silicon-containing 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:

9. 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 a resist underlayer film composition according to any one of claims 1 to 6 onto the substrate to be processed and then heat-treating the substrate; (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:

10. 10. The pattern formation method according to claim 7, wherein a substrate having a structure or steps with an aspect ratio of 10 or more is used as the substrate to be processed.

11. A method for forming a resist underlayer film that functions as an organic embedding film used in a manufacturing process of a semiconductor device, comprising spin-coating the resist underlayer film material according to any one of claims 1 to 6 onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied at a temperature of 100°C or higher and 600°C or lower for 10 to 600 seconds to form a hardened film.

12. 7. A method for forming a resist underlayer film that functions as an organic embedding film used in a manufacturing process of a semiconductor device, comprising spin-coating a resist underlayer film material according to any one of claims 1 to 6 onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied in an atmosphere with an oxygen concentration of 1% or more and 21% or less to form a hardened film.

13. 7. A method for forming a resist underlayer film that functions as an organic embedding film used in a manufacturing process of a semiconductor device, comprising spin-coating a resist underlayer film material according to any one of claims 1 to 6 onto a substrate to be processed, and heat-treating the substrate to which the resist underlayer film material has been applied in an atmosphere with an oxygen concentration of less than 1%, thereby forming a hardened film.

14. 14. The method for forming a resist underlayer film according to claim 11, wherein a substrate having a structure or steps with an aspect ratio of 10 or more is used as the substrate to be processed.

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