Method for forming a resist underlayer film, method for forming a pattern

Abstract

To provide: a method for forming a resist underlayer film that contains metal and that exhibits both a high filling property and high dry etching resistance; and a patterning method using the same.SOLUTION: A method for forming a resist underlayer film includes: a coating step of coating a substrate with a composition for forming a resist underlayer film containing a metal compound having a metal-oxygen covalent bond and an organic solvent; and a heating step of heating the coated substrate in an atmosphere having an oxygen concentration of less than 1 vol.% at a temperature from 450°C to 800°C inclusive. A compound comprising at least one or more crosslinking groups represented by general formulas (a-1) to (a-4) in the figure and specific formulas is used as the metal compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern dimensions is progressing rapidly. Lithography technology has achieved the formation of fine patterns in line with this miniaturization by shortening the wavelength of the light source and appropriately selecting the resist composition. At the heart of this is the single-layer positive photoresist composition. This single-layer positive photoresist composition has a framework in the resist resin that is resistant to dry etching with chlorine-based or fluorine-based gas plasma, and also has a switching mechanism that causes the exposed area to dissolve, thereby forming a pattern by dissolving the exposed area, and the remaining resist pattern is used as an etching mask to dry etch the substrate to be processed.

[0003] However, when the thickness of the photoresist film used was kept the same while miniaturization was achieved, i.e., the pattern width was reduced, the resolution performance of the photoresist film decreased. Furthermore, when attempting to develop the photoresist film using a developer, the aspect ratio became too large, resulting in pattern collapse. For this reason, as patterns became smaller, the photoresist film was made thinner.

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

[0005] From this, it becomes necessary to dry-etch the substrate to be processed with a thinner and weaker etching-resistant photoresist film, and ensuring the materials and processes in this processing step has become an urgent matter.

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

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

[0008] On the other hand, in recent years, the miniaturization of DRAM memory has accelerated, and the need for further improvements in dry etching resistance and resist underlayers with excellent embedding and planarization properties has increased. Examples of coated resist underlayer materials with excellent embedding and planarization properties include those described in Patent Document 2. Furthermore, Patent Document 3 reports that the dry etching resistance of resist underlayer materials can be improved by heat treatment at a temperature of 450 to 800°C in an atmosphere with an oxygen concentration of 1% by volume or less. However, when considering applications in the advanced generation, there are concerns about the dry etching resistance of resist underlayer materials, and the applicability limits of conventional coated resist underlayer materials are approaching.

[0009] To address the above challenges, development using materials containing metal elements in the resist underlayer film is being considered. Patent document 4 reports that materials using Ti compounds exhibit excellent dry etching resistance to CHF3 / CF4 gases and CO2 / N2 gases.

[0010] On the other hand, one challenge when using metal compounds as underlayer films for resists is their embedding properties. Although Patent Document 4 does not mention embedding properties, metal compounds generally exhibit significant thermal shrinkage during baking, and high-temperature baking induces a significant deterioration in their filling properties. Therefore, there are concerns that they may be insufficient as underlayer materials for resists that require high levels of planarization, embedding, and heat resistance.

[0011] Patent documents 5 and 6 report that metal compounds modified with specific ligands exhibit excellent embedding properties. However, the bake temperature used in the embedding evaluations is a low 150°C, raising concerns that this is insufficient for resist underlayers that require heat resistance (e.g., properties against heat treatments that may be applied after the formation of the resist underlayer). [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2004-205685 [Patent Document 2] Patent No. 6714493 [Patent Document 3] Patent No. 6711104 [Patent Document 4] Patent No. 6189758 [Patent Document 5] Patent No. 6786391 [Patent Document 6] Patent No. 7050137 [Overview of the project] [Problems that the invention aims to solve]

[0013] This invention has been made in view of the above circumstances, and aims to provide a method for forming a resist underlayer film containing a metal that achieves a high level of both embedding ability and dry etching resistance, and a method for forming a pattern using the same. [Means for solving the problem]

[0014] To solve the above problems, the present invention provides a method for forming a resist underlayer film, A coating step involves applying a resist underlayer film formation composition containing a metal compound having a metal-oxygen covalent bond and an organic solvent to a substrate, The process includes a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume at a temperature of 450°C to 800°C. The present invention provides a method for forming a resist underlayer film using a metal compound that contains at least one crosslinking group represented by the following general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3). [ka] (In general formulas (a-1) to (a-4), R a (where is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) [ka] (In general formulas (b-1) to (b-4), R b R is a hydrogen atom or a methyl group, and in the same formula they may be the same or different from each other. c (where * represents a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and * represents a bond.) [ka] (In general formulas (c-1) to (c-3), Y1 is a divalent organic group having 1 to 20 carbon atoms, R is a hydrogen atom, a substituted or unsubstituted saturated or unsaturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and R1 is an organic group whose protecting group is removed by the action of either or both of the following general formula (1) and / or heat, generating one or more hydroxyl or carboxyl groups, and * represents a bond.) [ka] (In general formula (1), R2 is an organic group whose protecting group is removed by the action of acid, heat, or both, and * represents the bond with Y1.)

[0015] This resist underlayer formation method significantly improves the dry etching resistance of metal-containing materials with excellent embedding properties, making it possible to form a resist underlayer containing metal that achieves a high level of both embedding and dry etching resistance, which was difficult to achieve with conventional techniques.

[0016] Furthermore, in the present invention, it is preferable that the oxygen concentration be 0.1% by volume or less.

[0017] By using this oxygen concentration, it is possible to improve dry etching resistance without impairing the embedding properties of the resist underlayer film.

[0018] Furthermore, in the present invention, it is preferable that the temperature be 500°C or higher and 600°C or lower.

[0019] Heating at such temperatures improves dry etching resistance without impairing the embedding properties of the resist underlayer.

[0020] Furthermore, in the present invention, it is preferable that the metal contained in the metal compound be titanium, zirconium, hafnium, or a combination thereof.

[0021] By including the above-mentioned metals, the resistance to dry etching during substrate processing can be further improved.

[0022] Furthermore, in the present invention, it is preferable to use a metal compound that further contains a ligand derived from a silicon compound represented by the following general formula (2). [ka] (In general formula (2), R 3A , R 3B and R 3C This is one of the following organic groups: an organic group having 2 to 30 carbon atoms having a bridging group in any of the structures shown by the general formulas (d-1) to (d-3) below; a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; and an aryl group having 6 to 20 carbon atoms. [ka] (In general formulas (d-1) to (d-3), R3 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.)

[0023] If a resist underlayer film formation method using a metal compound containing the aforementioned silicon-containing compound is used, it is possible to form a resist underlayer film with superior embedding properties.

[0024] Furthermore, the present invention provides a method for forming a pattern on a substrate to be processed, (I-1) A step of forming a resist underlayer film on a substrate to be processed using the resist underlayer film formation method described above, (I-2) A step of forming a silicon-containing resist interlayer on the resist underlayer, (I-3) A step of forming a resist upper layer film on the silicon-containing resist interlayer film using a photoresist material, (I-4) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (I-5) A step of transferring the pattern to the silicon-containing resist interlayer by dry etching, using the resist upper layer on which the pattern is formed as a mask. (I-6) A step of transferring the pattern to the resist underlayer film by dry etching, using the silicon-containing resist interlayer film on which the pattern has been transferred as a mask, and (I-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 having the following characteristics.

[0025] The above pattern formation method makes it possible to form fine patterns on a workpiece with high precision.

[0026] Furthermore, the present invention provides a method for forming a pattern on a substrate to be processed, (II-1) A step of forming a resist underlayer film on a substrate to be processed using the resist underlayer film formation method described above, (II-2) A step of forming an inorganic hard mask interlayer film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film, (II-3) A step of forming an organic thin film on the inorganic hard mask interlayer, (II-4) A step of forming a resist upper layer film on the organic thin film using a photoresist material, (II-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (II-6) A step of transferring the pattern to the organic thin film and the inorganic hard mask interlayer film by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (II-7) A step of transferring the pattern to the resist underlayer film by dry etching using the inorganic hard mask interlayer film on which the pattern has been transferred as a mask, and (II-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 having the following characteristics.

[0027] The above pattern formation method makes it possible to form fine patterns on a workpiece with high precision.

[0028] Furthermore, the present invention provides a method for forming a pattern on a substrate to be processed, (III-1) A step of forming a resist underlayer on a substrate to be processed using the resist underlayer formation method described above, (III-2) A step of forming an organic interlayer on the resist underlayer film, (III-3) A step of forming a combination of an organic thin film and an inorganic hard mask interlayer selected from a silicon-containing resist interlayer, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the organic interlayer. (III-4) A step of forming a resist upper layer film on the silicon-containing resist interlayer film or the organic thin film using a photoresist material, (III-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (III-6) A step of transferring the pattern to a silicon-containing resist interlayer or the organic thin film and the inorganic hard mask interlayer by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (III-7) A step of transferring the pattern to the organic interfilm by dry etching, using the silicon-containing resist interfilm or inorganic hard mask interfilm on which the pattern has been transferred as a mask. (III-8) A step of transferring the pattern to the resist underlayer film by dry etching using the organic interlayer film on which the pattern has been transferred as a mask, and (III-9) 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 having the following characteristics.

[0029] The above pattern formation method makes it possible to form fine patterns on a workpiece with high precision.

[0030] Furthermore, the present invention provides a method for forming a resist underlayer film, A coating step of applying a resist underlayer film formation composition containing metals belonging to the 3rd to 7th periods of Groups 3 to 15 of the periodic table to a substrate, The present invention provides a method for forming a resist underlayer film, comprising a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume% at a temperature of 450°C to 800°C.

[0031] This resist underlayer formation method significantly improves the dry etching resistance of metal-containing materials with excellent embedding properties, making it possible to form a resist underlayer containing metal that achieves a high level of both embedding and dry etching resistance, which was difficult to achieve with conventional techniques.

[0032] In this case, it is preferable to use a composition for forming the resist underlayer film that contains a metal compound having a metal-oxygen covalent bond or a metal compound having a metal-carbon covalent bond.

[0033] This method for forming a resist underlayer film makes it possible to create a resist underlayer film that achieves a high level of both embedding ability and dry etching resistance, which was difficult to achieve with conventional techniques. [Effects of the Invention]

[0034] As described above, the resist underlayer film formation method and pattern formation method of the present invention are particularly suitable for use in multilayer resist processes, including embedding / planarization of workpiece substrates with steps and irregularities, and are extremely useful in fine patterning for semiconductor device manufacturing. In particular, in fine patterning processes using the multilayer resist method in semiconductor device manufacturing processes, even on workpiece substrates that have areas that are difficult to embed / planarize, such as densely packed areas of high aspect ratio fine pattern structures represented by miniaturized DRAM memory, it is possible to embed without producing defects such as voids or peeling, and to form a resist underlayer film with excellent flatness characteristics. Furthermore, it exhibits superior etching resistance compared to conventional resist underlayer film formation methods, and this effect can be particularly achieved by heating at a temperature of 450°C to 800°C in an atmosphere with an oxygen concentration of less than 1 volume%. Therefore, fine patterns can be formed on the workpiece with even greater precision. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 is an explanatory diagram of an example of the pattern formation method of the present invention (3-layer resist process). [Figure 2] Figure 2 is an explanatory diagram of the embedding characteristics evaluation method. [Modes for carrying out the invention]

[0036] As described above, in the fine patterning process using the multilayer resist method, there has been a need for the development of a resist underlayer film formation method that can transfer resist patterns to the workpiece with higher precision, and a pattern formation method using this resist underlayer film formation method.

[0037] Generally, metal oxide compounds exhibit significant thermal shrinkage during baking, and after high-temperature baking, they induce a significant deterioration in filling properties. Therefore, there are concerns that they are insufficient as resist underlayer materials requiring advanced planarization, embedding, and heat resistance properties. Patent document 5 reports a metal-containing material with excellent embedding properties, but because it contains many organic components, it is considered to have insufficient dry etching resistance during substrate processing, which is a strength of metallic materials. There is a trade-off relationship between the embedding properties and dry etching resistance of metallic materials, and a breakthrough was needed. The inventors have developed a method for embedding carbon bonds contained in the metal-containing film after filling in steps. Solution We hypothesized that we could improve dry etching resistance without degrading embedding properties by promoting separation and recombination, and we conducted extensive research. As a result, we found that a resist underlayer formation method in which the metal-containing resist underlayer film is heated at a temperature of 450°C to 800°C in an atmosphere with an oxygen concentration of less than 1 volume% significantly improves the dry etching resistance during substrate processing without impairing the embedding properties of the resist underlayer film, thus completing the present invention.

[0038] In other words, the present invention is a method for forming a resist underlayer film, A coating step involves applying a resist underlayer film formation composition containing a metal compound having a metal-oxygen covalent bond and an organic solvent to a substrate, The process includes a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume at a temperature of 450°C to 800°C. This method for forming a resist underlayer film uses a metal compound that contains at least one crosslinking group represented by the following general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3). [ka] (In general formulas (a-1) to (a-4), R a (where is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) [ka] (In general formulas (b-1) to (b-4), R b is a hydrogen atom or a methyl group, and in the same formula, they may be the same as or different from each other. R c is a hydrogen atom, a substituted or unsubstituted monovalent organic group having 1 to 20 carbon atoms, which may be saturated or unsaturated, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and * represents a bonding site.)

Chemical formula

Chemical formula

[0039] Further, the present invention is a method for forming a resist underlayer film, comprising: a coating step of coating a substrate with a composition for forming a resist underlayer film containing a metal belonging to the 3rd to 15th groups and the 3rd to 7th periods of the periodic table; a heating step of heating the coated substrate at a temperature of 450 °C or higher and 800 °C or lower in an atmosphere with an oxygen concentration of less than 1% by volume. This is a method for forming a resist underlayer film.)

[0040] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0041] <Method for forming a resist underlayer film> The present invention relates to a method for forming a resist underlayer film, A coating step of applying a resist underlayer film formation composition containing metals belonging to the 3rd to 7th periods of Groups 3 to 15 of the periodic table to a substrate, The method for forming a resist underlayer film comprises a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume% at a temperature of 450°C to 800°C.

[0042] This method for forming a resist underlayer film allows for the creation of a resist underlayer film with excellent etching resistance during substrate processing without compromising embedding properties.

[0043] In this case, it is preferable to use a composition for forming the resist underlayer film that contains a metal compound having a metal-oxygen covalent bond or a metal compound having a metal-carbon covalent bond.

[0044] This method for forming a resist underlayer film makes it possible to create a resist underlayer film that achieves a high level of both embedding ability and dry etching resistance, which was difficult to achieve with conventional techniques.

[0045] Furthermore, the present invention relates to a method for forming a resist underlayer film, A coating step involves applying a resist underlayer film formation composition containing a metal compound having a metal-oxygen covalent bond and an organic solvent to a substrate, The process includes a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume at a temperature of 450°C to 800°C. This method for forming a resist underlayer film uses a metal compound that contains at least one crosslinking group represented by the following general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3). [ka] (In general formulas (a-1) to (a-4), R a (where is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) [ka] (In general formulas (b-1) to (b-4), R b R is a hydrogen atom or a methyl group, and in the same formula they may be the same or different from each other. c (where * represents a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and * represents a bond.) [ka] (In general formulas (c-1) to (c-3), Y1 is a divalent organic group having 1 to 20 carbon atoms, R is a hydrogen atom, a substituted or unsubstituted saturated or unsaturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and R1 is an organic group whose protecting group is removed by the action of either or both of the following general formula (1) and / or heat, generating one or more hydroxyl or carboxyl groups, and * represents a bond.) [ka] (In general formula (1), R2 is an organic group whose protecting group is removed by the action of acid, heat, or both, and * represents the bond with Y1.)

[0046] This method for forming a resist underlayer film allows for the creation of a resist underlayer film with excellent etching resistance during substrate processing without compromising embedding properties.

[0047] The oxygen concentration during heating is less than 1 volume percent in the atmosphere, preferably 0.1 volume percent or less, more preferably 0.01 volume percent or less, and even more preferably 0.005 volume percent or less.

[0048] By performing heat treatment at the above oxygen concentration, rapid volume shrinkage of the resist underlayer film can be suppressed, and organic components in the resist underlayer film can be gently removed, thereby improving dry etching resistance without impairing embedding properties. Furthermore, even if the substrate to be processed is susceptible to air oxidation, substrate damage can be suppressed by forming the resist underlayer film by heat treatment in an atmosphere with an oxygen concentration of less than 1 volume%.

[0049] The bake temperature of the resist underlayer film is between 450°C and 800°C, preferably between 450°C and 650°C, and more preferably between 500°C and 600°C. The bake time is preferably in the range of 10 seconds to 7,200 seconds, and more preferably in the range of 30 seconds to 600 seconds.

[0050] By appropriately adjusting the bake temperature and time within the above range, planarization and embedding characteristics suitable for the application, as well as curing characteristics such as dry etching resistance and heat resistance, can be obtained. By performing baking within a temperature range of 450°C to 800°C, the organic components in the resist underlayer film are decomposed, and modification to a metal oxide film is promoted, thus forming a resist underlayer film with excellent dry etching resistance. If the bake temperature is below 450°C, the organic components in the film cannot be reduced. If the bake temperature exceeds 800°C, the crystallization of the metal-containing film cannot be suppressed. Heating can also be performed in multiple stages (step baking).

[0051] <Composition for forming a resist underlayer film> The resist underlayer film formation composition used in the resist underlayer film formation method of the present invention is a resist underlayer film formation composition containing a metal belonging to the 3rd to 7th periods of Groups 3 to 15 of the periodic table.

[0052] Metals belonging to the 3rd to 7th periods of the periodic table, Groups 3 to 15, include: Examples of Group 3 metals include scandium, yttrium, lanthanum, and cerium. Examples of Group 4 metals include titanium, zirconium, and hafnium. Examples of Group 5 metals include vanadium, niobium, and tantalum. Examples of metals in Group 6 include chromium, molybdenum, and tungsten. Metals in Group 7 include manganese and rhenium, Metals in Group 8 include iron, ruthenium, and osmium. Metals in Group 9 include cobalt, rhodium, and iridium. Metals in Group 10 include nickel, palladium, and platinum. Metals in Group 11 include copper, silver, and gold. Metals in Group 12 include zinc, cadmium, and mercury. Metals in Group 13 include aluminum, gallium, and indium. Metals in Group 14 include germanium, tin, and lead. Examples of metals in Group 15 include antimony and bismuth.

[0053] Metals from Groups 4-6 and 13-15 are more preferred, with titanium, zirconium, and hafnium being even more preferred.

[0054] Such a resist underlayer formation composition can provide a resist underlayer film exhibiting extremely excellent dry etching resistance. The resist underlayer formation method of the present invention can improve dry etching resistance without degrading the embedding properties of the resist underlayer film.

[0055] In this case, it is preferable to use a composition for forming the resist underlayer film that contains a metal compound having a metal-oxygen covalent bond or a metal compound having a metal-carbon covalent bond.

[0056] This method for forming a resist underlayer film makes it possible to create a resist underlayer film that achieves a high level of both embedding ability and dry etching resistance, which was difficult to achieve with conventional techniques.

[0057] Furthermore, the resist underlayer film formation composition used in the resist underlayer film formation method of the present invention is a resist underlayer film formation composition containing (A) a metal compound and (B) an organic solvent.

[0058] Such a resist underlayer film formation composition contains a metal compound that exhibits a high degree of both thermal fluidity and thermosetting properties, thus providing a resist underlayer film that shows excellent embedding / planarization characteristics and, when subjected to high-temperature baking treatment, exhibits extremely excellent dry etching resistance. Because it can form a resist underlayer film with excellent heat resistance, dry etching resistance can be improved without degrading the embedding characteristics through high-temperature baking treatment.

[0059] [(A) Metal compound] The metal compound contained in the resist underlayer forming composition used in the resist underlayer forming method of the present invention has a metal-oxygen covalent bond and contains at least one crosslinking group represented by the following general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3). [ka] (In general formulas (a-1) to (a-4), R a (where is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) [ka] (In general formulas (b-1) to (b-4), R b R is a hydrogen atom or a methyl group, and in the same formula they may be the same or different from each other. c (where * represents a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and * represents a bond.) [ka] (In general formulas (c-1) to (c-3), Y1 is a divalent organic group having 1 to 20 carbon atoms, R is a hydrogen atom, a substituted or unsubstituted saturated or unsaturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and R1 is an organic group whose protecting group is removed by the action of either or both of the following general formula (1) and / or heat, generating one or more hydroxyl or carboxyl groups, and * represents a bond.) [ka] (In general formula (1), R2 is an organic group whose protecting group is removed by the action of acid, heat, or both, and * represents the bond with Y1.)

[0060] The metal compound has high etching resistance because it contains a metal-oxygen covalent bond.

[0061] The metal compound contains at least one crosslinking group represented by the general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3), thereby forming a resist underlayer film with excellent embedding properties. Furthermore, since a resist underlayer film with excellent heat resistance can be formed, baking within a temperature range of 450°C to 800°C can improve dry etching resistance without degrading embedding properties.

[0062] The ligands coordinating to the metal compound are not particularly limited as long as one or more ligands having a bridging group represented by the general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3) are coordinated. However, from the viewpoint of stability, carboxylates, acetyl acetates, polyhydric alcohols, etc., are preferred.

[0063] Examples of ligands containing the bridging group shown in the above general formulas (a-1) to (a-4) include, but are not limited to, the following compounds. [ka] (In the above formula, R 1A (This represents an organic group selected from substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, and aryl groups having 6 to 20 carbon atoms.)

[0064] [ka]

[0065] [ka] (In the above formula, X1 and X2 represent hydrocarbon groups having 1 to 20 carbon atoms or alkoxy groups having 1 to 20 carbon atoms.)

[0066] [ka] (In the above formula, X1 and X2 represent hydrocarbon groups having 1 to 20 carbon atoms or alkoxy groups having 1 to 20 carbon atoms.)

[0067] [ka] (In the above formula, R 1A X1 represents an organic group selected from substituted or unsubstituted C1-C20 alkyl groups and C6-C20 aryl groups, while X1 and X2 represent C1-C20 hydrocarbon groups or C1-C20 alkoxy groups.

[0068] [ka] (In the above formula, R 1A R represents one of the organic groups selected from substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, and aryl groups having 6 to 20 carbon atoms. a (This represents a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms.)

[0069] [ka]

[0070] [ka] (In the above formula, X1 and X2 represent hydrocarbon groups having 1 to 20 carbon atoms or alkoxy groups having 1 to 20 carbon atoms.)

[0071] [ka] (In the above formula, X1 and X2 represent hydrocarbon groups having 1 to 20 carbon atoms or alkoxy groups having 1 to 20 carbon atoms.)

[0072] [ka] (In the above formula, X1 and X2 represent hydrocarbon groups having 1 to 20 carbon atoms or alkoxy groups having 1 to 20 carbon atoms.)

[0073] [ka] (In the above formula, Y is a divalent organic group having 1 to 10 carbon atoms.)

[0074] Examples of ligands containing the bridging group shown in the above general formulas (b-1) to (b-4) include, but are not limited to, the following compounds.

[0075] [ka] (In the above formula, R c (This can be a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms.)

[0076] [ka] (In the above formula, Rc X1 is a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; X1 and X2 represent a hydrocarbon group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; and Y is a divalent organic group having 1 to 10 carbon atoms.

[0077] Examples of ligands containing the bridging group shown in the above general formulas (c-1) to (c-3) include, but are not limited to, the following compounds. [ka]

[0078] In the above general formulas (c-1) to (c-3), one or more hydroxyl groups or carboxyl groups generated by the elimination of a protecting group due to the action of acid, heat, or both function as a bridging group.

[0079] The metal contained in the above metal compound is preferably titanium, zirconium, hafnium, or a combination thereof.

[0080] By including a metal compound containing the above-mentioned metal in the resist underlayer film formation composition, the dry etching resistance during substrate processing can be further improved.

[0081] It is preferable to use a metal compound that further contains a ligand derived from a silicon compound represented by the following general formula (2). [ka] (In general formula (2), R 3A , R 3B and R 3C This is one of the following organic groups: an organic group having 2 to 30 carbon atoms having a bridging group in any of the structures shown by the general formulas (d-1) to (d-3) below; a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; and an aryl group having 6 to 20 carbon atoms. [ka] (In general formulas (d-1) to (d-3), R3 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.)

[0082] In the above general formula (2), R 3A , R 3B and R 3C The C2-C30 organic group having a bridging group in any of the structures represented by the general formulas (d-1) to (d-3) above, a substituted or unsubstituted C1-C20 alkyl group, and an aryl group having 6 to 20 carbon atoms are selected from these organic groups, with the C2-C30 organic group having a bridging group in any of the structures represented by the general formulas (d-1) to (d-3) above, or an unsubstituted C1-C10 alkyl group being more preferred. Among the unsubstituted C1-C10 alkyl groups, a methyl group or an ethyl group is more preferred.

[0083] In the general formulas (d-1) to (d-3) above, R3 is independently a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and q is independently 0 or 1.

[0084] By including a ligand derived from the silicon compound represented by the general formula (2) above in the above metal compound, the stability of the metal compound in the resist underlayer film forming composition is improved, and the fluidity of the resist underlayer film forming composition can be improved.

[0085] From the viewpoint of thermosetting properties, it is more preferable that the ligand derived from the silicon compound represented by the above general formula (2) has one of the structures represented by the following general formula (2A). [ka] (In general formula (2A), R 3D and R 3E (where R3 is an organic group selected from substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms and aryl groups having 6 to 20 carbon atoms, R3 is the same as above, and s is 1 to 10.)

[0086] In the above general formula (2A), R 3D and R 3E From the perspective of raw material availability, it is more preferable that it be a methyl group.

[0087] If, in addition to ligands containing crosslinking groups represented by the general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3) above, the ligands derived from the silicon compound also contain crosslinking groups, the thermosetting properties of the resist underlayer film formation composition can be further improved. When this composition is used for forming a resist underlayer film, it becomes possible to form a resist underlayer film with excellent embedding / planarization properties.

[0088] The above metal compound can be modified with multiple ligands of different structures or ligands derived from silicon compounds, as long as it has one or more ligands containing bridging groups represented by the general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3), and can be appropriately adjusted according to the required properties. Furthermore, the above metal compound may have ligands other than those containing bridging groups represented by the general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3) and ligands derived from silicon compounds. For example, it may contain ligands derived from alkyl groups having 1 to 10 carbon atoms.

[0089] In the above metal compounds, the content of ligands containing the bridging groups represented by the above general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3) is preferably 10 mol% to 100 mol%, and more preferably 20 mol% to 80 mol%, of the total amount of ligands coordinating to the metal atoms. Ligands derived from silicon compounds are preferably 0 mol% to 90 mol%, and more preferably 20 mol% to 80 mol%, of the total amount of ligands coordinating to the metal atoms. Ligands other than those derived from silicon compounds and those containing the crosslinking group represented by the general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3) above, such as ligands derived from alkyl groups having 1 to 10 carbon atoms, are preferably present in an amount of 0 mol% to 50 mol%, and more preferably 0 mol% to 20 mol%, of the total amount of ligands coordinating to the metal atom.

[0090] The following describes the components included in the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention, other than the metal compounds (A) described above.

[0091] <(B) Organic solvents> The (B) organic solvent that can be used in the resist underlayer forming composition used in the resist underlayer forming method of the present invention is not particularly limited as long as it dissolves or disperses the (A) metal compound described above, and, if included, the (C) crosslinking agent, (E) surfactant, (F) acid generator, and other additives described later.

[0092] Specifically, organic solvents described in paragraphs

[0091] to

[0092] of Japanese Patent Publication No. 2007-199653 can be added. More specifically, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, and γ-butyrolactone, or a mixture containing one or more of these, are preferably used.

[0093] The amount of organic solvent blended is preferably in the range of 200 to 10,000 parts by mass, more preferably 250 to 5,000 parts by mass, per 100 parts by mass of (A) metal compound.

[0094] The resist underlayer film forming composition may contain one or more of the above-mentioned (A) metal compounds and (B) organic solvents, and may optionally contain (C) a crosslinking agent, (E) a surfactant, and (F) an acid generator. The following describes the components included in the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention, other than the metal compounds (A) described above.

[0095] <(B1) High boiling point solvent> In the resist underlayer film forming composition used in the resist underlayer film forming method 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°C and one or more organic solvents having a boiling point of 180°C or higher ((B1) high-boiling point solvents).

[0096] (B1) As for the high boiling point solvent, there are no particular restrictions on hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc., as long as it can dissolve or disperse each component of the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention. 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 Dibutyl 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 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, which may be used individually or in combination.

[0097] (B1) The high-boiling point solvent can be appropriately selected from the above, for example, according to the temperature at which the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention is heat-treated. The boiling point of the high-boiling point solvent is preferably 180°C to 300°C, and more preferably 200°C to 300°C. With such a boiling point, there is no risk of excessive volatilization during baking (heat treatment), so sufficient thermal fluidity can be obtained during film formation, and it is thought that a resist underlayer film with excellent embedding / planarization properties can be formed. Furthermore, with such a boiling point, there is no risk of residual solvent in the film after baking without volatilization, so there is no risk of adverse effects on film properties such as etching resistance.

[0098] Furthermore, when using (B1) a high-boiling point solvent, the amount blended is preferably 1 to 30 parts by mass per 100 parts by mass of an organic solvent with a boiling point of less than 180°C. Such a blending amount is preferable because it provides sufficient thermal fluidity during baking, does not remain in the film, and does not lead to deterioration of film properties such as etching resistance.

[0099] [(C) Crosslinking agent] Furthermore, the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention may further contain a (C) crosslinking agent in order to enhance the curability of the metal compound and further suppress intermixing with the resist upper layer film. The (C) crosslinking agent is not particularly limited, and various known types of crosslinking agents can be widely used. Examples include melamine-based crosslinking agents, acrylate-based crosslinking agents, glycoluryl-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 (for example, methylol or alkoxymethyl type crosslinking agents of polynuclear phenols). The content of the (C) crosslinking agent is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, per 100 parts by mass of the (A) metal compound.

[0100] Examples of melamine-based crosslinking agents include hexamethoxymethylated melamine, hexasubtoxicmethylated melamine, alkoxy and / or hydroxy-substituted derivatives thereof, and partially self-condensed derivatives thereof. As an example of an acrylate-based crosslinking agent, dipentaerythritol hexaacrylate can be cited. Examples of glycoluryl crosslinking agents include tetramethoxymethylated glycoluryl, tetrabutoxymethylated glycoluryl, their alkoxy and / or hydroxy substituted derivatives, and their partial self-condensates. Examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, their alkoxy and / or hydroxy-substituted derivatives, and their partial self-condensed derivatives. Examples of urea-based crosslinking agents include dimethoxymethylated dimethoxyethyleneurea, its alkoxy and / or hydroxy-substituted derivatives, and partially self-condensed derivatives thereof. A specific example of a β-hydroxyalkylamide crosslinking agent is N,N,N',N'-tetra(2-hydroxyethyl)adipamide. Examples of isocyanurate-based crosslinking agents include triglycidyl isocyanurate and triallyl isocyanurate. Examples of aziridine-based crosslinking agents include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate]. Examples of oxazoline-based crosslinking agents include 2,2'-isopropylidenebis(4-benzyl-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 copolymers. 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.

[0101] Examples of polynuclear phenolic crosslinking agents include the compound represented by the following general formula (XL-1). [ka] (In the general formula (XL-1), Q is a single bond or a q'-valent hydrocarbon group having 1 to 20 carbon atoms. R'3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. q' is an integer from 1 to 5.)

[0102] Q is a single bond or a q'-valent hydrocarbon group having 1 to 20 carbon atoms. q' is an integer from 1 to 5, more preferably 2 or 3. Examples of Q include methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane, with q' hydrogen atoms removed. R'3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. Examples of alkyl groups having 1 to 20 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, octyl, ethylhexyl, decyl, and eicosanyl groups, with hydrogen atoms or methyl groups being preferred.

[0103] As examples of compounds represented by the above general formula (XL-1), the following compounds can be specifically exemplified. Among these, triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and hexamethoxymethylated tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferred from the viewpoint of improving the curability and uniformity of the resist underlayer film. R'3 is the same as above. [ka]

[0104] [ka]

[0105] <(E) Surfactants> The resist underlayer film forming composition used in the resist underlayer film forming method of the present invention may contain (E) surfactant to improve the coatability in spin coating. As the (E) surfactant, for example, those described in paragraphs

[0142] to

[0147] of Japanese Patent Application Publication No. 2009-269953 can be used. When adding the (E) surfactant, the amount to be added is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the (A) metal compound.

[0106] <(F) Acid Generator> In the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention, an (F) acid generator can be added to further promote the curing reaction of the (A) metal compound. The (F) acid generator may be one that generates acid by thermal decomposition or one that generates acid by light irradiation, and either type can be added. Specifically, the materials described in paragraphs

[0061] to

[0085] of Japanese Patent Application Publication No. 2007-199653 can be added, but are not limited to these.

[0107] The above (F) acid generating agent can be used individually or in combination of two or more types. When adding the (F) acid generating agent, the amount to be added is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the above (A) metal compound.

[0108] <Other additives> Furthermore, the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention preferably includes, for example, a liquid additive having a polyethylene glycol or polypropylene glycol structure, or a pyrolytic polymer having a mass loss rate of 40% by mass or more between 30°C and 250°C and a weight-average molecular weight of 300 to 200,000, as an additive to impart embedding / planarization properties. This pyrolytic polymer preferably contains repeating units having an acetal structure represented by the following general formulas (DP1) and (DP1a).

[0109] [ka] (In the general formula (DP1), R6 is a hydrogen atom or a monovalent saturated or unsaturated organic group having 1 to 30 carbon atoms, which may be substituted. Y2 is a divalent saturated or unsaturated organic group having 2 to 30 carbon atoms.)

[0110] [ka] (In general formula (DP1a), R 6a Y is an alkyl group having 1 to 4 carbon atoms. a (where n is a saturated or unsaturated divalent hydrocarbon group having 4 to 10 carbon atoms, and may have an ether bond. n represents the average number of repeating units, ranging from 3 to 500.)

[0111] <Flow enhancer (BP)> Furthermore, a fluidity enhancer (BP) may be added to the resist underlayer film formation composition used in the resist underlayer film formation method of the present invention as an additive to impart embedding / planarization properties. The fluidity enhancer (BP) preferably has an organic group represented by the following general formula (3) and an aromatic ring. [ka] (In general formula (3), * represents a bonding site to the oxygen atom, R B R is a divalent organic group with 1 to 10 carbon atoms. A (This refers to a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.)

[0112] The fluidity enhancer (BP) having the organic group of the general formula (3) above can impart thermal fluidity and thermosetting properties to the resist underlayer film forming composition. Furthermore, the fluidity enhancer (BP) having an aromatic ring can mitigate the deterioration of the dry etching resistance of the resist underlayer film forming composition.

[0113] The aforementioned fluidity enhancer (BP) preferably has at least one constituent unit represented by the following general formulas (BP-1), (BP-2), (BP-3), (BP-4), and (BP-5). (Component units: BP-1, BP-2, and BP-3) [ka] (In general formulas (BP-1) and (BP-2), W1 and W2 are independently a benzene ring or a naphthalene ring, and the hydrogen atoms in the benzene ring and naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. a (4) is the group represented by formula (4) below. Y3 is the group represented by formula (5) below. n1 is 0 or 1, n2 is 1 or 2, and V independently represents a hydrogen atom or a linkage. [ka] (In the general formula (BP-3), Z1 is the base shown in the general formula (6) below, R a This is the group represented by formula (4) below. n4 is 0 or 1, n5 is 1 or 2, and V independently represents a hydrogen atom or a linkage. [ka] (In equation (4), * represents the bond with the oxygen atom.) [ka] (In equation (5), * represents a bond.) [ka] (In general formula (6), W1, W2, Y3, and n1 are the same as described above.)

[0114] Resins having the constituent units shown by the above general formulas (BP-1), (BP-2), and (BP-3) have excellent heat resistance because they incorporate high-carbon-density condensed carbon rings including a cardi structure. Due to these characteristics, even when subjected to high-temperature baking treatment, a resist underlayer film can be formed that can fill stepped substrates without generating voids. Furthermore, because it also has excellent dry etching resistance, when added to the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention, it can impart heat resistance and thermal fluidity without significantly degrading the excellent dry etching resistance of the metal compound.

[0115] The resin having the constituent units represented by the above general formulas (BP-1), (BP-2), and (BP-3) may be the compound represented by the following general formulas (bp-1), (bp-2), and / or (bp-3). [ka] (In general formulas (bp-1) and (bp-2), W1, W2, R a (Y3, n1, and n2 are the same as above.)

[0116] In the above general formulas (bp-1) and (bp-2), W1, W2, R a Y3, n1, and n2 are as explained above for general formulas (BP-1) and (BP-2).

[0117] [ka] (In general formula (bp-3), Z1, R a n4 and n5 are the same as above.

[0118] In the above general formula (bp-3), Z1, R a n4 and n5 are as explained above for the general formula (BP-3).

[0119] Examples of resins having the constituent units represented by the above general formulas (bp-1), (bp-2), and (bp-3) include, but are not limited to, the following compounds. [ka] (In the formula, R a (This is the same as above.)

[0120] The above compounds (bp-1), (bp-2), and (bp-3) are preferably such that the ratio Mw / Mn (i.e., degree of dispersion) of the weight-average molecular weight Mw to the number-average molecular weight Mn, measured by gel permeation chromatography in terms of polystyrene, is within the range of 1.00 ≤ Mw / Mn ≤ 1.25, and more preferably 1.00 ≤ Mw / Mn ≤ 1.10.

[0121] If the compound has a dispersion degree within this range, the thermal fluidity of the resist underlayer film formation composition will be even better, and when incorporated into the resist underlayer film formation composition, it will be possible to provide a resist underlayer film formation composition with superior embedding / planarization properties.

[0122] The resin having the constituent units represented by the above general formulas (BP-1), (BP-2), and (BP-3) may be a polymer having repeating units represented by the following general formulas (bp-4), (bp-5), and / or (bp-6). [ka] (In general formulas (bp-4) and (bp-5), W1, W2, R a Y3, n1, and n2 are the same as described above, and L is a divalent organic group with 1 to 40 carbon atoms.

[0123] In the above general formulas (bp-4) and (bp-5), W1, W2, R a Y3, n1, and n2 are as explained above for general formulas (BP-1) and (BP-2).

[0124] [ka] (In general formula (bp-6), Z1, R a n4 and n5 are the same as described above, and L is a divalent organic group with 1 to 40 carbon atoms.

[0125] In the above general formula (bp-6), Z1, R a n4 and n5 are as explained above for the general formula (BP-3).

[0126] These polymers are obtained using compounds represented by the above general formulas (bp-1), (bp-2), and (bp-3), and because they use these compounds, they exhibit excellent dry etching resistance and heat resistance. Furthermore, because they are polymers with repeating units rather than monomers, they have fewer outgassing components, and because they are polymers with a molecular weight distribution, their crystallinity is relaxed, and improved film-forming properties can be expected.

[0127] The linking group L that constitutes the repeating units of the above general formulas (bp-4), (bp-5), and (bp-6) is a divalent organic group having 1 to 40 carbon atoms, and the following are some specific examples. [ka]

[0128] Furthermore, it is preferable that the linking group L of the polymer is of the following general formula (10). [ka] (In general formula (10), R'1 is an organic group containing a hydrogen atom or an aromatic ring with 6 to 20 carbon atoms, and the dashed lines represent bonding.)

[0129] The following are some specific examples of the above general formula (10), and among them, a methylene group, i.e., R'1 being a hydrogen atom, is preferred due to the ease of obtaining the raw materials. [ka]

[0130] Furthermore, the weight-average molecular weight (Mw) of the polymer having the repeating structural units represented by the above general formulas (bp-4), (bp-5), and (bp-6) in terms of polystyrene, as determined by gel permeation chromatography, is preferably 1,000 to 12,000, and more preferably Mw is 2,000 to 10,000.

[0131] Within this molecular weight range, solubility in organic solvents can be ensured, and sublimation during baking can be suppressed. Furthermore, the thermal fluidity of the resist underlayer film forming composition is good, so when incorporated into the resist underlayer film forming composition, it is possible to provide a resist underlayer film forming composition with superior embedding / planarization properties.

[0132] (Component unit: BP-4) [ka] (In general formula (BP-4), m3 and m4 represent 1 or 2, and Z is either a single bond or one of the structures shown in general formula (7) below. x (This is one of the structures shown in the following general formula (8).) [ka] (In general formula (7), * represents an association, l represents an integer from 0 to 3, and R' a ~R' f Each of these independently represents a hydrogen atom or a C1-C10 alkyl group, phenyl group, or phenylethyl group which may be substituted with fluorine, and R' a and R' b (They may combine to form a cyclic compound.) [ka] (In general formula (8), * represents the bonding site to the aromatic ring, and Q1 is Number of carbon atoms It consists of 1 to 30 linear saturated hydrocarbon groups, or a structure represented by the general formula (9) below. [ka] (In general formula (9), * represents the bonding site to the carbonyl group, R i R is the group shown in formula (4) above. j This includes linear or branched hydrocarbon groups having 1 to 10 carbon atoms, halogen atoms, nitro groups, amino groups, nitrile groups, alkoxycarbonyl groups having 2 to 10 carbon atoms, or carbon atoms 2 Represents up to 10 alkanoyloxy groups. n'3 and n'4 represent the number of substituents on the aromatic ring, each an integer from 0 to 7. However, n'3 + n'4 is between 0 and 7 (inclusive). n'5 represents 0 to 2.

[0133] In the above general formula (BP-4), m3 and m4 represent 1 or 2, and Z is either a single bond or one of the structures shown in the above general formula (7). x is one of the structures shown in the general formula (8) above.

[0134] From the viewpoint of dry etching resistance and heat resistance, it is preferable that Z in the above general formula (BP-4) is either a single bond or a structure represented by the following general formula (4A). [ka] (In general formula (4A), * represents a bond, and l is the same as above.)

[0135] In the above general formula (8), * represents the bonding site to the aromatic ring, and Q1 is Number of carbon atoms Q1 is a linear saturated hydrocarbon group having 1 to 30 carbon atoms, or a structure represented by the general formula (9) above. When Q1 represents a linear hydrocarbon group having 1 to 30 carbon atoms, the methylene group constituting Q1 may be substituted with an oxygen atom or a carbonyl group. From the viewpoint of dry etching resistance and heat resistance, the structure represented by the general formula (9) above is preferred for Q1.

[0136] In the above general formula (9), * represents the bonding site to the carbonyl group, and R i R is the group shown in formula (4) above. jThis includes linear or branched hydrocarbon groups having 1 to 10 carbon atoms, halogen atoms, nitro groups, amino groups, nitrile groups, alkoxycarbonyl groups having 2 to 10 carbon atoms, or carbon atoms 2 Represents up to 10 alkanoyloxy groups. n'3 and n'4 represent the number of substituents on the aromatic ring, each representing an integer from 0 to 7. However, n'3 + n'4 is between 0 and 7. n'5 represents 0 to 2.

[0137] Compounds containing the constituent units shown in the above general formula (BP-4) have a structure in which aromatic rings are linked by single bonds or general formula (7), and therefore have a high carbon density. As a result, compositions for forming resist underlayer films containing these compounds have excellent heat resistance. Furthermore, as shown in the above general formula (7), the linking group Z can be appropriately selected from various linking groups to match the desired performance. In particular, by introducing the structure shown in the above general formula (4A) as Z, heat resistance / etching resistance can be imparted without impairing film formation properties. In addition, the highly flexible terminal portion R x Because it has a rigid aromatic ring structure, it is possible to form a thick film of the resist underlayer film-forming composition without generating defects such as cracks. Furthermore, terminal portion R x The compound contains terminal groups Q1 that impart thermal fluidity. As terminal groups Q1, a flexible hydrocarbon structure that contributes to improved thermal fluidity and a rigid aromatic ring structure that contributes to etching resistance and heat resistance can be introduced in any proportion to suit the required performance. As described above, the resist underlayer film formation composition with these compounds added can achieve a high level of both embedding / planarization properties and heat resistance, and thick film formation is possible according to the required properties.

[0138] (Component unit: BP-5) [ka] (In general formula (BP-5), R 1 R is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, and R ais the base shown in equation (4) above. p is an integer between 0 and 5, q1 is an integer between 1 and 6, p+q1 is an integer between 1 and 6 (inclusive), and q2 is either 0 or 1.

[0139] In the above general formula (BP-5), the divalent organic group having 1 to 30 carbon atoms represented by X is, for example, an alkanediyl group such as methylene group, ethanediyl group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, octanediyl group, decanediyl group, etc.; a monocyclic cycloalkanediyl group such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group, cycloheptanediyl group, cyclooctanediyl group, cyclodecanediyl group, methylcyclohexanediyl group, ethylcyclohexanediyl group, etc.; bicyclo[2.2.1]heptanediyl group, bicyclo[2.2.2]octanediyl group, tricyclo[5.2.1.0 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 Examples include polycyclic cycloalkanediyl groups such as dodecanediyl and adamantanediyl groups, and arenediyl groups such as phenylene and naphthylene groups.

[0140] Examples of the alkanediyloxy group represented by X above include a group formed by combining the alkanediyl group with an oxygen atom. Similarly, examples of the cycloalkanediyloxy group represented by X above include a group formed by combining the cycloalkanediyl group with an oxygen atom.

[0141] Some or all of the hydrogen atoms in the above-mentioned alkanediyl group, cycloalkanediyl group, alkanediyloxy group, cycloalkanediyloxy group, and arenediyl group may be substituted, and examples of substituents include the above-mentioned R a Examples of substituents that the organic group represented by [the symbol] may have include groups similar to those mentioned above.

[0142] Examples of the organic group represented by X above include groups represented by the following formulae. [Chemical formula] (In the formula, * represents a bond.)

[0143] From the perspective of raw material availability, X above preferably includes a methylene group.

[0144] Specific examples of the resin having the structural unit represented by the general formula (BP-5) above include the following. [Chemical formula] (In the formula, R a is the same as above.)

[0145] [Chemical formula] (In the formula, R a is the same as above.)

[0146] Since the polymer containing the structural unit represented by the general formula (BP-5) above has a structure in which aromatic rings are connected by the organic group X, it has a high carbon density. Therefore, the resist underlayer film-forming composition containing these polymers exhibits high dry etching resistance and excellent heat resistance. Furthermore, since the organic group having the structure represented by the above formula (4), which contributes to the improvement of thermal fluidity, is directly bonded to the aromatic ring, which is the mother nucleus structure of the resin, through an oxygen atom, the resist underlayer film-forming composition added with these polymers can achieve high-dimensional compatibility between embedding / flattening characteristics and heat resistance / etching resistance. In addition, since the aromatic ring structure of the mother nucleus is not too rigid and forms a repeating structure through the organic group X, which is a linking group, it is possible to form a resist underlayer film without generating defects such as cracks.

[0147] In the resist underlayer film forming composition used in the resist underlayer film forming method of the present invention, the fluidity accelerator (BP) is preferably contained in an amount of 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, per 100 parts by mass of the metal compound.

[0148] The amount of fluidity enhancer added can be adjusted to any ratio according to the required characteristics of the process using the resist underlayer film formation composition used in the resist underlayer film formation method of the present invention. If you want to minimize the degradation of dry etching resistance, reduce the proportion of the fluidity enhancer. If you want to tolerate some degradation of dry etching resistance and further improve the embedding / planarization characteristics, increase the proportion of the fluidity enhancer.

[0149] <Pattern formation method using a resist underlayer film formation method> Furthermore, in the present invention, as a pattern formation method by a two-layer resist process using the above resist underlayer film formation method, A resist underlayer film is formed on the substrate to be processed using the above resist underlayer film formation method. A resist upper layer film is formed on the resist lower layer film using a photoresist material. After pattern exposure of the resist upper layer film, it is developed with a developer to form a pattern on the resist upper layer film. Using the resist upper layer film on which the pattern is formed as a mask, the pattern is transferred to the resist lower layer film by dry etching. The present invention provides a pattern forming method for forming a pattern on a substrate by processing the substrate using the resist underlayer film on which the pattern is formed as a mask.

[0150] Since the upper resist film of the above two-layer resist process exhibits etching resistance to chlorine-based gases, it is preferable to perform the dry etching of the lower resist film, which is carried out using the upper resist film as a mask, with an etching gas mainly composed of chlorine-based gases in the above two-layer resist process.

[0151] Furthermore, the present invention provides a method for forming a pattern on a workpiece substrate using a three-layer resist process with such a resist underlayer film formation method, (I-1) A step of forming a resist underlayer film on a substrate to be processed using the resist underlayer film formation method described above, (I-2) A step of forming a silicon-containing resist interlayer on the resist underlayer, (I-3) A step of forming a resist upper layer film on the silicon-containing resist interlayer film using a photoresist material, (I-4) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (I-5) A step of transferring the pattern to the silicon-containing resist interlayer by dry etching, using the resist upper layer on which the pattern is formed as a mask. (I-6) A step of transferring the pattern to the resist underlayer film by dry etching, using the silicon-containing resist interlayer film on which the pattern has been transferred as a mask, and (I-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 having the following characteristics.

[0152] A pattern formation method using a three-layer resist process will be explained with reference to Figure 1. In the present invention, as a pattern formation method using a three-layer resist process with such a resist underlayer film formation method, a resist underlayer film 3 is formed on a workpiece layer 2 on a workpiece substrate 1 using the above resist underlayer film formation method, as shown in Figure 1(A), a silicon-containing resist interlayer film 4 is formed on the resist underlayer film using a silicon-containing resist interlayer material, and a resist upper layer film 5 is formed on the silicon-containing resist interlayer film using a photoresist material. The present invention provides a pattern formation method in which, as shown in Figure 1(B), the exposed portion 6 of the resist upper layer film is pattern-exposed, and as shown in Figure 1(C), it is developed with a developer to form a resist upper layer film pattern 5a on the resist upper layer film, as shown in Figure 1(D), the silicon-containing resist interlayer film pattern 4a is transferred to the silicon-containing resist interlayer film by dry etching using the resist upper layer film with the pattern formed on it as a mask, as shown in Figure 1(E), the resist lower layer film pattern 3a is transferred to the resist lower layer film by dry etching using the silicon-containing resist interlayer film with the transferred pattern as a mask, and as shown in Figure 1(F), the workpiece layer on the workpiece is processed using the resist lower layer film with the pattern formed on it as a mask to form a pattern 2a on the workpiece substrate 1.

[0153] Since the silicon-containing resist interlayer in the above three-layer resist process exhibits etching resistance to chlorine-based gases, it is preferable to perform the dry etching of the resist underlayer using the silicon-containing resist interlayer as a mask in the above three-layer resist process using an etching gas mainly composed of chlorine-based gases.

[0154] As the silicon-containing resist intermediate film in the above three-layer resist process, a polysiloxane-based intermediate film is also preferably used. By imparting an antireflection effect to the silicon-containing resist intermediate film, reflection can be suppressed. Particularly for 193 nm exposure, when a material with a large number of aromatic groups as an organic film and high etching selectivity with respect to the substrate is used, the k value becomes high and the substrate reflection becomes high. However, by providing absorption such that the k value becomes appropriate as the silicon-containing resist intermediate film, it becomes possible to suppress reflection and reduce the substrate reflection to 0.5% or less. As the silicon-containing resist intermediate film having an antireflection effect, polysiloxane having an anthracene pendant for 248 nm and 157 nm exposure, and a phenyl group or an absorbing group having a silicon-silicon bond pendant for 193 nm exposure and crosslinked by an acid or heat is preferably used.

[0155] In addition, in the present invention, as a pattern forming method by a four-layer resist process using such a resist underlayer film forming method, a resist underlayer film is formed on the substrate to be processed using the above resist underlayer film forming method, a silicon-containing resist intermediate film is formed on the resist underlayer film using a silicon-containing resist intermediate film material, an organic antireflection film (BARC) or an adhesion film is formed on the silicon-containing resist intermediate film, a resist upper layer film is formed on the BARC or the adhesion film using a photoresist material, after the resist upper layer film is pattern-exposed, it is developed with a developer to form a pattern in the resist upper layer film, using the resist upper layer film in which the pattern is formed as a mask, the pattern is transferred to the BARC or the adhesion film and the silicon-containing resist intermediate film by dry etching, using the silicon-containing resist intermediate film in which the pattern is transferred as a mask, the pattern is transferred to the resist underlayer film by dry etching, A pattern forming method is provided, which includes a step of processing the substrate to be processed using the resist underlayer film in which the pattern is formed as a mask to form a pattern on the substrate to be processed.

[0156] Alternatively, an inorganic hard mask interlayer may be formed instead of a silicon-containing resist interlayer. In this case, at least the resist underlayer is formed on the workpiece using the resist underlayer formation method of the present invention. An inorganic hard mask interlayer film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film is formed on the resist underlayer film. A resist upper layer film is formed on the inorganic hard mask interlayer film using a photoresist composition, and a circuit pattern is formed on the resist upper layer film. Using the resist upper layer film on which the aforementioned pattern is formed as a mask, the inorganic hard mask interlayer film is etched. The resist underlayer film is etched using the inorganic hard mask interlayer film on which the aforementioned pattern is formed as a mask. Furthermore, by using the resist underlayer film on which the pattern is formed as a mask to etch the workpiece and form a pattern on the workpiece, a semiconductor device circuit pattern can be formed on the substrate.

[0157] As described above, when forming an inorganic hard mask interlayer on a resist underlayer, silicon oxide films, silicon nitride films, and silicon oxynitride films (SiON films) can be formed by CVD or ALD methods. For example, a method for forming a silicon nitride film is described in Japanese Patent Application Publication No. 2002-334869 and International Publication No. 2004 / 066377. The thickness of the inorganic hard mask interlayer is preferably 5 to 200 nm, and more preferably 10 to 100 nm. Furthermore, as the inorganic hard mask interlayer, a SiON film with high anti-reflective properties is most preferably used. Since the substrate temperature when forming the SiON film is 300 to 500°C, the resist underlayer needs to withstand temperatures of 300 to 500°C. The resist underlayer formation composition used in the present invention has high heat resistance and can withstand high temperatures of 300 to 500°C, so it is possible to combine an inorganic hard mask interlayer formed by CVD or ALD with a resist underlayer formed by rotary coating.

[0158] As described above, a photoresist film may be formed as a resist top layer on an inorganic hard mask interlayer, or an organic anti-reflective coating (BARC) or adhesion film may be formed on the inorganic hard mask interlayer by spin coating, and then a photoresist film may be formed on top of that. In particular, when a SiON film is used as the inorganic hard mask interlayer, the two layers of anti-reflective coatings, the SiON film and BARC, make it possible to suppress reflection even in immersion lithography with high NA values ​​exceeding 1.0. Another advantage of forming BARC is that it has the effect of reducing the trailing of the photoresist pattern directly above the SiON film.

[0159] Furthermore, the present invention provides a method for forming a pattern on a substrate to be processed, (II-1) A step of forming a resist underlayer film on a substrate to be processed using the resist underlayer film formation method described above, (II-2) A step of forming an inorganic hard mask interlayer film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film, (II-3) A step of forming an organic thin film on the inorganic hard mask interlayer, (II-4) A step of forming a resist upper layer film on the organic thin film using a photoresist material, (II-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (II-6) A step of transferring the pattern to the organic thin film and the inorganic hard mask interlayer film by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (II-7) A step of transferring the pattern to the resist underlayer film by dry etching using the inorganic hard mask interlayer film on which the pattern has been transferred as a mask, and (II-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 having the following characteristics.

[0160] In the pattern formation method described above, the resist upper layer film may be either positive or negative type, and the same photoresist composition as commonly used can be used. Furthermore, the photoresist composition may contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, and Zn. When forming the resist upper layer film using the above photoresist composition, the method may be spin coating, CVD, or ALD deposition.

[0161] When forming a resist upper layer film by spin coating, pre-baking is performed after coating the photoresist composition, preferably at a temperature of 60 to 180°C for 10 to 300 seconds. Subsequently, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain the resist upper layer film pattern. The thickness of the resist upper layer film is not particularly limited, but 10 to 500 nm, and especially 20 to 400 nm, is preferred.

[0162] When a resist upper layer film is formed by vapor deposition using the CVD or ALD method, the photoresist composition is an EUV-sensitive metal oxide-containing film, the metal being selected from Sn, Zr, Hf, Ti, Bi, Sb, etc., with Sn being preferred due to its excellent EUV photosensitivity. The metal oxide-containing film may be a photosensitive organometallic oxide film such as an organotin oxide (e.g., haloalkylSn, alkoxyalkylSn, or amidealkylSn). Some specific examples of suitable precursors include trimethyltin chloride, dimethyltin dichloride, methyltin trichloride, tris(dimethylamino)methyltin(IV), and (dimethylamino)trimethyltin(IV).

[0163] The metal oxide-containing film may be deposited by PECVD or PEALD using, for example, a Lam Vector® tool, and in the ALD example, the Sn oxide precursor is separated from the O precursor / plasma. The deposition temperature is preferably in the range of 50°C to 600°C. The deposition pressure is preferably between 100 and 6,000 mTorr. The flow rate of the metal oxide-containing film precursor liquid (e.g., organotin oxide precursor) may be 0.01 to 10 cm, and the gas flow rate (CO2, CO, Ar, N2) may be 100 to 10,000 sccm. The plasma power may be 200 to 1,000 W per 300 mm wafer station using a high-frequency plasma (e.g., 13.56 MHz, 27.1 MHz, or higher frequency). The deposition thickness is preferably 100 to 2,000 Å.

[0164] Examples of exposure light include high-energy rays with wavelengths of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays, electron beams, and X-rays with wavelengths of 3 to 20 nm.

[0165] As a method for forming the pattern of the resist upper layer film described above, it is preferable to use photolithography with a wavelength of 5 nm to 300 nm, direct writing with an electron beam, nanoimprinting, or a combination thereof to form the pattern.

[0166] Furthermore, it is preferable that the development method in the pattern formation method be alkaline development or development with an organic solvent.

[0167] Next, etching is performed using the obtained resist upper layer pattern as a mask. In the three-layer resist process, etching of the silicon-containing resist interlayer and inorganic hard mask interlayer is performed using a fluorocarbon gas with the resist upper layer pattern as a mask. This forms the silicon-containing resist interlayer pattern and the inorganic hard mask interlayer pattern.

[0168] Next, the resist underlayer is etched using the obtained silicon-containing resist interlayer pattern or inorganic hard mask interlayer pattern as a mask. It is preferable to use an etching gas mainly composed of chlorine-based gas for the etching of the resist underlayer.

[0169] The etching of the next workpiece can also be performed by conventional methods. For example, if the workpiece is made of SiO2, SiN, or silica-based low dielectric constant insulating film, etching is performed primarily using a fluorocarbon gas. When the substrate is etched with a fluorocarbon gas, the silicon-containing resist interlayer pattern in the three-layer resist process is peeled off simultaneously with the substrate processing.

[0170] The resist underlayer film obtained by the resist underlayer film formation method of the present invention has the characteristic of excellent etching resistance when these workpieces are etched.

[0171] The workpiece (workpiece substrate) is not particularly limited and can be any substrate such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, Al, or a substrate on which the workpiece layer has been deposited. Various low-k films and their stopper films can be used as the workpiece layer, typically with a thickness of 50 to 10,000 nm, and especially 100 to 5,000 nm. When depositing the workpiece layer, the substrate and the workpiece layer are made of different materials.

[0172] The pattern formation method using the resist underlayer formation method of the present invention preferably uses a workpiece substrate having a structure or step with a height of 30 nm or more. As described above, the resist underlayer formation composition used in the resist underlayer formation method of the present invention has excellent embedding / planarization characteristics, so even if the workpiece substrate has a structure or step (unevenness) with a height of 30 nm or more, a flat resist underlayer can be formed. The height of the structure or step on the workpiece substrate is preferably 30 nm or more, more preferably 50 nm or more, and even more preferably 100 nm or more. In the method of processing a stepped substrate having a pattern of the above height, by forming the resist underlayer formation composition used in the resist underlayer formation method of the present invention and performing embedding / planarization, it is possible to make the film thickness of the silicon-containing resist interlayer and resist upper layer that are subsequently formed uniform, which makes it easier to secure the depth of exposure margin (DOF) during photolithography and is highly preferable.

[0173] Furthermore, in the present invention, as a pattern formation method using a four-layer resist process employing such a resist underlayer film formation method, A resist underlayer film is formed on the substrate to be processed using the resist underlayer film formation method described above. An organic interlayer is formed on the resist underlayer using an organic interlayer material. A silicon-containing resist interlayer is formed on the aforementioned organic interlayer using a silicon-containing resist interlayer material. If necessary, an organic anti-reflective coating (BARC) or an adhesion coating is formed on the silicon-containing resist interlayer. A resist upper layer film is formed on the silicon-containing resist interlayer film or on the BARC or the adhesion film using a photoresist material. After pattern exposure of the resist upper layer film, it is developed with a developer to form a pattern on the resist upper layer film. Using the resist upper layer film on which the pattern is formed as a mask, the pattern is transferred to the BARC or the adhesion film and the silicon-containing resist interlayer film by dry etching. Using the silicon-containing resist interlayer on which the aforementioned pattern has been transferred as a mask, the pattern is transferred to the organic interlayer by dry etching. The pattern is transferred to the resist underlayer film using the organic interlayer film on which the pattern is formed as a mask. The present invention provides a pattern formation method comprising the step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed.

[0174] Furthermore, the present invention provides a method for forming a pattern on a workpiece substrate using a four-layer resist process with such a resist underlayer film formation method, (III-1) A step of forming a resist underlayer on a substrate to be processed using the resist underlayer formation method described above, (III-2) A step of forming an organic interlayer on the resist underlayer film, (III-3) A step of forming a combination of an organic thin film and an inorganic hard mask interlayer selected from a silicon-containing resist interlayer, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the organic interlayer. (III-4) A step of forming a resist upper layer film on the silicon-containing resist interlayer film or the organic thin film using a photoresist material, (III-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (III-6) A step of transferring the pattern to a silicon-containing resist interlayer or the organic thin film and the inorganic hard mask interlayer by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (III-7) A step of transferring the pattern to the organic interfilm by dry etching, using the silicon-containing resist interfilm or inorganic hard mask interfilm on which the pattern has been transferred as a mask. (III-8) A step of transferring the pattern to the resist underlayer film by dry etching using the organic interlayer film on which the pattern has been transferred as a mask, and (III-9) 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 having the following characteristics.

[0175] As organic interlayer materials that can be used for the above-mentioned organic interlayer, in addition to those already known as underlayers for the 3-layer resist method or the 2-layer resist method using a silicon resist composition, a large number of resins including novolac resins can be used, such as the 4,4'-(9-fluorenylidene)bisphenol novolac resin (molecular weight 11,000) described in Japanese Patent Application Publication No. 2005-128509, as well as those known as underlayer materials for resists in the 2-layer resist method and the 3-layer resist method. Furthermore, if it is desired to increase the heat resistance compared to ordinary novolac, a polycyclic skeleton such as 6,6'-(9-fluorenylidene)-di(2-naphthol) novolac resin can be incorporated, and polyimide resins can also be selected (for example, Japanese Patent Application Publication No. 2004-153125).

[0176] The above-mentioned organic interfilm can be formed on a substrate using a composition solution by a spin coating method or the like, similar to the photoresist composition. After forming the organic interfilm by a spin coating method or the like, it is desirable to bake it to evaporate the organic solvent. The baking temperature is preferably in the range of 80 to 400°C, and the baking time is preferably in the range of 10 to 300 seconds.

[0177] Instead of the organic interlayer described above, it is also possible to apply an organic hard mask formed by CVD or ALD.

[0178] Since the organic interlayer in the above multilayer resist process exhibits etching resistance to chlorine-based gases, it is preferable to perform the dry etching of the resist underlayer using the organic interlayer as a mask in the above multilayer resist process using an etching gas mainly composed of chlorine-based gases. [Examples]

[0179] The present invention will be described in more detail below with reference to synthesis examples, comparative synthesis examples, examples, and comparative examples, but the present invention is not limited thereto.

[0180] [Example of combination] The following synthesis examples used the organic group raw materials G: (G1) to (G20) and the silicon-containing organic group raw materials H: (H1) to (H5) shown below. The organic raw material group G: (G1) to (G20) is shown below. [ka]

[0181] The silicon-containing organic raw material group H:(H1)~(H5) is shown below. [ka]

[0182] The following metal compounds were used as the metal raw material M. (M1): Titanium tetraisopropoxide (Sigma-Aldrich Corp, 377996) (M2): Titanium butoxide tetramer (Fujifilm Wako Pure Chemical Corporation) (M3):Zr(OBu)4:Zirconium(IV) tetrabutoxide (80% by mass 1-butanol solution) (Tokyo Chemical Industries, Ltd., Z0016) (M4):Hf(OBu)4:Hafnium(IV)n-butoxide (Sigma-Aldrich Corp, 667943) (M5):Ti(OBu)4:Tetrabutyl orthotitanate (Tokyo Chemical Industries, Ltd., B0742) (M6): Titanium(IV) diisopropoxybis(2,4-pentanedionate) (75% by mass isopropyl alcohol solution) (Tokyo Chemical Industries, Ltd., B3395)

[0183] [Synthesis Example 1] Synthesis of Compound (A-1) for Forming a Resist Underlayer Film Under a nitrogen atmosphere, 12.1 g of IPA solution containing 33.4 g of titanium tetraisopropoxide (M1) was stirred, and 24.2 g of IPA solution containing 1.6 g of deionized water was added dropwise over 2 hours at room temperature. 16.6 g of organic raw material group (G1) was added to the resulting solution and stirred at room temperature for 30 minutes. This solution was concentrated under reduced pressure at 30°C, then heated to 60°C, and continued under reduced pressure until no more distillate was observed. Once no distillate was observed, 69.0 g of PGMEA / PGME (mass ratio 70 / 30) solution was added, and the mixture was heated at 40°C under reduced pressure until no more IPA distilled, yielding a PGMEA / PGME solution of the resist underlayer film forming compound (A-1). The concentration of components other than the solvent in the solution was 20% by mass.

[0184] [Synthesis Examples 2-4] Synthesis of Compounds (A-2)-(A-4) for Resist Underlayer Film Formation Compounds for forming the resist underlayer film shown in Table 1 (A-2) to (A-4) were obtained under the same reaction conditions as in Synthesis Example 1, except that the above-mentioned metal raw material M and organic group raw material group G were used in the amounts shown in Table 1. [Table 1]

[0185] [Synthesis Example 5] Synthesis of Compound (A-5) for Forming a Resist Underlayer Film Under a nitrogen atmosphere, 11.8 g of tetrabutyl orthotitanate (M5) was dissolved in 20.6 g of PGMEA / PGME (mass ratio 70 / 30) solution, and the reaction temperature was raised to 50°C while stirring. 6.5 g of silicon-containing organic raw material group (H1) was then added dropwise to the solution. After addition, the reaction temperature was increased to 60°C and stirring was continued for 2 hours. Next, a mixture of 4.8 g of organic raw material group (G5) suspended in 8.6 g of PGMEA / PGME (mass ratio 70 / 30) solution was added to the reaction system, and stirring was continued at a reaction temperature of 60°C for 1 hour. After cooling to room temperature, the resulting reaction solution was filtered through a 0.45 μm PTFE filter to obtain a PGMEA / PGME solution of the resist underlayer film forming compound (A-5). The concentration of components other than the solvent in the solution was 23% by mass.

[0186] [Synthesis Examples 6-20] Synthesis of Compounds (A-6)-(A-20) for Forming Underlayer Films of Resists Compounds for forming the resist underlayer film shown in Table 2 (A-6) to (A-20) were obtained under the same reaction conditions as in Synthesis Example 5, except that the above metal raw material M, above organic group raw material group G, and above silicon-containing organic group raw material group H were used in the amounts shown in Table 2. [Table 2]

[0187] [Synthesis of resin (R-1) for forming a resist underlayer film for comparative examples] Under a nitrogen atmosphere, 160.2 g of 1,5-dihydroxynaphthalene, 56.8 g of formaldehyde, 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 p-toluenesulfonic acid monohydrate and 8.0 g of PGME, which had been pre-mixed and homogenized, was slowly added dropwise, and the reaction was carried out at an internal temperature of 80°C for 8 hours. After the reaction was complete, the mixture was cooled to room temperature, 2,000 ml of MIBK was added, and the mixture was washed six times with 500 ml of pure water. The organic layer was dried under reduced pressure. 300 g of THF was added to the residue to make a homogeneous 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 recovered. The recovered crystals were vacuum-dried at 70°C to obtain a resin (R-1) for forming a resist underlayer film for comparative examples. The weight-average molecular weight (Mw) and dispersion (Mw / Mn) were determined by gel permeation chromatography (GPC) using tetrahydrofuran as the eluent, and the following results were obtained. (R-1): Mw=3,300, Mw / Mn=2.54 [ka]

[0188] [Preparation of composition for forming a resist underlayer film (UDL-1)] A resist underlayer film forming composition (UDL-1) was prepared by dissolving the resist underlayer film forming compound (A-1) in a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) containing 0.5% by mass of the surfactant FC-4430 (manufactured by Sumitomo 3M Co., Ltd.) in the proportions shown in Table 3, and filtering the mixture through a 0.02 μm membrane filter.

[0189] [Preparation of resist underlayer film formation compositions (UDL-2 to 20) and comparative resist underlayer film formation compositions (comparative example UDL-1)] Each composition was prepared in the same manner as UDL-1, except that the type and content of each component were as shown in Table 3. In Table 3, "-" indicates that the corresponding component was not used. The following formula (F-1) was used as the acid generator (TAG).

[0190] [Acid Generator] The acid generator (F-1) used in the resist underlayer film formation composition is shown below. [ka]

[0191] [Table 3]

[0192] [Evaluation of embedding characteristics (Examples 1-1 to 1-17, Comparative Examples 1-1 to 1-2)] The compositions prepared above (UDL-1 to 17, and Comparative Example UDL-1) were each coated onto an SiO2 wafer substrate having a dense line and space pattern (line width 60 nm, line depth 100 nm, distance between the centers of two adjacent lines 120 nm), heated at 350°C for 60 seconds using a hot plate, and then heated at 500°C for 60 seconds under a nitrogen atmosphere (oxygen concentration 0.01 vol%) to form a resist underlayer film with a thickness of 80 nm. In Comparative Examples 1-2, a resist underlayer film was formed by heating at 500°C for 60 seconds in an air atmosphere.

[0193] The substrate used was a base substrate 7 (SiO2 wafer substrate) having a dense line and space pattern as shown in Figure 2(G) (overhead view) and (H) (cross-sectional view). The cross-sectional shape of each wafer substrate obtained in the embedding characteristic evaluation was observed using an electron microscope (S-4700) manufactured by Hitachi, Ltd. to confirm whether there were any voids (gaps) inside the resist underlayer film that filled the spaces between the lines. The results are shown in Table 4. When a resist underlayer film formation composition with poor embedding characteristics was used, voids were generated inside the resist underlayer film that filled the spaces between the lines in this evaluation. When a resist underlayer film formation composition with good embedding characteristics was used, a resist underlayer film 8 without voids was filled inside the resist underlayer film that filled the spaces between the lines of the base substrate 7 having a dense line and space pattern as shown in Figure 2(I) in this evaluation.

[0194] [Table 4]

[0195] As shown in Table 4, in Examples 1-1 to 1-17 using the resist underlayer film formation method of the present invention, it was possible to fill dense line and space patterns without generating voids even after baking at 500°C by controlling the oxygen concentration, and it was confirmed that good filling characteristics were maintained even under high-temperature baking conditions. In Comparative Examples 1-2, where a resist underlayer film was formed by heating at 500°C for 60 seconds in an atmospheric environment, voids were observed at the bottom of the pattern. Even when using the resist underlayer film formation composition UDL-1, which contains a resist underlayer film formation compound (A-1) having an organic crosslinking group, high-temperature baking in an atmospheric environment results in significant volume shrinkage, which is undesirable from the viewpoint of embedding ability.

[0196] [Etching resistance evaluation (Examples 2-1 to 2-20, Comparative Example 2-1)] The resist underlayer film formation compositions (UDL-1 to 20, and Comparative Example UDL-1) were applied to a silicon substrate and heated at 350°C for 60 seconds using a hot plate. death, A resist underlayer film with a thickness of 80 nm was formed (film thickness a). Separately from the above evaluation, a substrate coated with the above composition and heated at 350°C for 60 seconds was further heated at 500°C for 60 seconds under a nitrogen atmosphere (oxygen concentration 0.01 vol%) to form a resist underlayer film with a thickness of 80 nm (film thickness a). Next, etching was performed using CF4 gas under the following conditions with a ULVAC CE-300I etching system, and the film thickness b was measured. The etching rate (nm / min) was calculated from the film thickness etched per minute (film thickness a - film thickness b) over a specified time using each gas. The results are shown in Table 5.

[0197] Dry etching conditions with CF4 gas Pressure: 1 Pa Antenna RF power: 100W Bias RF Power: 15W CF4 gas flow rate: 15 sccm Time: 30sec

[0198] [Table 5]

[0199] As shown in Table 5, Examples 2-1 to 2-20 using the resist underlayer film formation method of the present invention showed extremely superior etching resistance to CF4 gas compared to Comparative Example 2-1, which used Comparative Example UDL-1, a resist underlayer film formation composition containing the comparative example resist underlayer film formation resin (R-1). Furthermore, it was found that etching resistance improved with high-temperature baking under controlled oxygen concentration. Compared to Examples 2-18 to 2-20, which used resist underlayer film formation compositions UDL-1 to UDL-17, which contain resist underlayer film formation compounds (A-1) to (A-17) containing organic crosslinking groups, Examples 2-1 to 2-17 showed a greater improvement in etching resistance with 500°C baking. The reason for this is not clear, but it is possible that the organic crosslinking components in the resist underlayer film are cleaved and re-crosslinked by high-temperature baking, causing densification of the film.

[0200] [Pattern formation method (Examples 3-1 to 3-17, Comparative Example 3-1)] The above resist underlayer formation compositions (UDL-1 to 17, Comparative Example UDL-1) were each applied to an SiO2 wafer substrate, baked in air at 350°C for 60 seconds, and then baked again at 500°C for 60 seconds in an oxygen concentration of 0.01 volume% to form a resist underlayer with a thickness of 80 nm. A silicon atom-containing resist interlayer material (SOG-1) was applied on top of this and baked at 220°C for 60 seconds to form a resist interlayer with a thickness of 50 nm. An ArF single-layer resist, which is a resist toplayer material, was applied on top of this and baked at 105°C for 60 seconds to form a photoresist film with a thickness of 100 nm. An immersion protective film material (TC-1) was applied on top of the photoresist film and baked at 90°C for 60 seconds to form a protective film with a thickness of 50 nm.

[0201] As a silicon atom-containing resist interlayer material (SOG-1), a polymer represented by ArF silicon-containing interlayer polymer (SiP1) and a thermal crosslinking catalyst (CAT1) were dissolved in an organic solvent containing 0.1% by mass of FC-4430 (manufactured by Sumitomo 3M Co., Ltd.) in the proportions shown in Table 6, and the mixture was filtered through a fluororesin filter with a pore size of 0.1 μm to prepare the silicon atom-containing resist interlayer material (SOG-1).

[0202] [Table 6]

[0203] The structural formulas of the ArF silicon-containing interlayer polymer (SiP1) and thermal crosslinking catalyst (CAT1) used are shown below. [ka]

[0204] The resist upper layer material (single-layer resist for ArF) was prepared by dissolving a polymer (RP1), an acid generator (PAG1), and a basic compound (Amine1) in the proportions shown in Table 7 in a solvent containing 0.1% by mass of the surfactant FC-4430 (manufactured by Sumitomo 3M Co., Ltd.), and filtering the mixture through a 0.1 μm fluororesin filter.

[0205] [Table 7]

[0206] The polymer (RP1), acid generator (PAG1), and basic compound (Amine1) used in the resist upper layer material (single-layer resist for ArF) are shown below. [ka]

[0207] The immersion protective film material (TC-1) was prepared by dissolving the protective film polymer (PP1) in an organic solvent in the proportions shown in Table 8 and filtering it through a 0.1 μm fluororesin filter.

[0208] [Table 8]

[0209] The protective film polymer (PP1) used in the immersion protective film material (TC-1) is shown below. [ka]

[0210] Next, the sample was exposed using an ArF immersion lithography system (Nikon Corporation; NSR-S610C, NA 1.30, σ 0.98 / 0.65, 35-degree dipole s polarized illumination, 6% halftone phase shift mask), baked (PEB) at 100°C for 60 seconds, and developed with a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds to obtain a 55 nm 1:1 positive-type line-and-space pattern (resist upper layer pattern).

[0211] Next, a hard mask pattern was formed by dry etching, using the resist upper layer pattern as a mask to etch the resist interlayer. The resulting hard mask pattern was then used as a mask to etch the resist lower layer to form the resist lower layer pattern. Finally, the resulting resist lower layer pattern was used as a mask to etch the SiO2 film. The etching conditions are as follows.

[0212] Transfer conditions for the resist upper layer pattern to the resist interlayer. Dry etching conditions with CF4 gas Pressure: 1 Pa Antenna RF power: 100W Bias RF Power: 15W CF4 gas flow rate: 15 sccm Time: 60sec

[0213] Transfer conditions for hard mask patterns to the resist underlayer film. Dry etching conditions with Cl2 gas Pressure: 1 Pa Antenna RF power: 320W Bias RF Power: 30W Cl2 gas flow rate: 25 sccm Time: 45 sec

[0214] Transfer conditions for resist underlayer film patterns onto SiO2 film. Dry etching conditions with CF4 gas Pressure: 1 Pa Antenna RF power: 100W Bias RF Power: 15W CF4 gas flow rate: 15 sccm Time: 60sec

[0215] Table 9 shows the results of observing the pattern cross-section using an electron microscope (S-4700) manufactured by Hitachi, Ltd.

[0216] [Table 9]

[0217] As shown in Table 9, in all cases, the pattern formation method of the present invention (Examples 3-1 to 3-17) successfully transferred the resist upper film pattern to the substrate, confirming its suitability for microfabrication using the multilayer resist method. On the other hand, Comparative Example 3-1, which used Comparative Example UDL-1, which showed insufficient performance in the dry etching resistance evaluation, resulted in distortion of the pattern shape during pattern processing, and ultimately failed to obtain a good pattern.

[0218] Based on the above, the resist underlayer film formation method and pattern formation method of the present invention are particularly suitable for use in multilayer resist processes that include embedding / planarization of workpieces with steps and irregularities, and are extremely useful in fine patterning for semiconductor device manufacturing.

[0219] This specification includes the following embodiments: [1] A method for forming a resist underlayer film, A coating step involves applying a resist underlayer film formation composition containing a metal compound having a metal-oxygen covalent bond and an organic solvent to a substrate, The process includes a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume at a temperature of 450°C to 800°C. A method for forming a resist underlayer film, characterized in that the aforementioned metal compound contains at least one crosslinking group represented by the following general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3). [ka] (In general formulas (a-1) to (a-4), R a (where is a hydrogen atom or a monovalent organic group with 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) [ka] (In general formulas (b-1) to (b-4), R b R is a hydrogen atom or a methyl group, and in the same formula they may be the same or different from each other. c (where * represents a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and * represents a bond.) [ka] (In general formulas (c-1) to (c-3), Y1 is a divalent organic group having 1 to 20 carbon atoms, R is a hydrogen atom, a substituted or unsubstituted saturated or unsaturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and R1 is an organic group whose protecting group is removed by the action of either or both of the following general formula (1) and / or heat, generating one or more hydroxyl or carboxyl groups, and * represents a bond.) [ka] (In general formula (1), R2 is an organic group whose protecting group is removed by the action of acid, heat, or both, and * represents the bond with Y1.) [2]: The resist underlayer film formation method according to [1], characterized in that the oxygen concentration is 0.1 volume% or less. [3]: The resist underlayer film formation method according to [1] or [2] above, characterized in that the temperature is 500°C or more and 600°C or less. [4]: A method for forming a resist underlayer film according to any one of the above [1] to [3], characterized in that the metal contained in the metal compound is titanium, zirconium, hafnium, or a combination thereof. [5]: A method for forming a resist underlayer film according to any one of the above [1] to [4], characterized in that the metal compound further contains a ligand derived from a silicon compound represented by the following general formula (2). [ka] (In general formula (2), R 3A , R 3B and R 3C This is one of the following organic groups: an organic group having 2 to 30 carbon atoms having a bridging group in any of the structures shown by the general formulas (d-1) to (d-3) below; a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms; and an aryl group having 6 to 20 carbon atoms. [ka] (In general formulas (d-1) to (d-3), R3 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) [6]: A method for forming a pattern on a substrate to be processed, (I-1) A step of forming a resist underlayer on a substrate to be processed by any one of the resist underlayer forming methods described in [1] to [5] above, (I-2) A step of forming a silicon-containing resist interlayer on the resist underlayer, (I-3) A step of forming a resist upper layer film on the silicon-containing resist interlayer film using a photoresist material, (I-4) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (I-5) A step of transferring the pattern to the silicon-containing resist interlayer by dry etching, using the resist upper layer on which the pattern is formed as a mask. (I-6) A step of transferring the pattern to the resist underlayer film by dry etching, using the silicon-containing resist interlayer film on which the pattern has been transferred as a mask, and (I-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 characterized by having the following features. [7] A method for forming a pattern on a substrate to be processed, (II-1) A step of forming a resist underlayer on a substrate to be processed by any one of the resist underlayer forming methods described in [1] to [5] above, (II-2) A step of forming an inorganic hard mask interlayer film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film, (II-3) A step of forming an organic thin film on the inorganic hard mask interlayer, (II-4) A step of forming a resist upper layer film on the organic thin film using a photoresist material, (II-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (II-6) A step of transferring the pattern to the organic thin film and the inorganic hard mask interlayer film by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (II-7) A step of transferring the pattern to the resist underlayer film by dry etching using the inorganic hard mask interlayer film on which the pattern has been transferred as a mask, and (II-8) A step of processing the substrate to be processed using the resist underlayer film on which the pattern has been formed as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by having the following features. [8] A method for forming a pattern on a substrate to be processed, (III-1) A step of forming a resist underlayer on a substrate to be processed by any one of the resist underlayer forming methods described in [1] to [5] above, (III-2) A step of forming an organic interlayer on the resist underlayer film, (III-3) A step of forming a combination of an organic thin film and an inorganic hard mask interlayer selected from a silicon-containing resist interlayer, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the organic interlayer. (III-4) A step of forming a resist upper layer film on the silicon-containing resist interlayer film or the organic thin film using a photoresist material, (III-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (III-6) A step of transferring the pattern to a silicon-containing resist interlayer or the organic thin film and the inorganic hard mask interlayer by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (III-7) A step of transferring the pattern to the organic interfilm by dry etching, using the silicon-containing resist interfilm or inorganic hard mask interfilm on which the pattern has been transferred as a mask. (III-8) A step of transferring the pattern to the resist underlayer film by dry etching using the organic interlayer film on which the pattern has been transferred as a mask, and (III-9) 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 characterized by having the following features. [9] A method for forming a resist underlayer film, A coating step of applying a resist underlayer film formation composition containing metals belonging to the 3rd to 7th periods of Groups 3 to 15 of the periodic table to a substrate, A method for forming a resist underlayer film, characterized by comprising a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume% at a temperature of 450°C to 800°C.

[10] : The resist underlayer film formation method according to [9], characterized in that the resist underlayer film formation composition includes a metal compound having a metal-oxygen covalent bond or a metal compound having a metal-carbon covalent bond.

[0220] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0221] 1...Substrate to be processed, 2...Layer to be processed, 2a...Pattern (pattern formed on the processed layer), 3...Resist underlayer film, 3a…Resist underlayer pattern, 4…Silicon-containing resist interlayer, 4a...Silicon-containing resist interlayer pattern, 5...Resist top layer, 5a…Resist upper layer pattern, 6…Exposed area, 7…Underlayment substrate with densely packed lines and spaces, 8…Resist underlayer film.

Claims

1. A method for forming a resist underlayer film, A coating step involves applying a resist underlayer film formation composition containing a metal compound having a metal-oxygen covalent bond and an organic solvent to a substrate, The process includes a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume percent at a temperature of 450°C to 800°C. A method for forming a resist underlayer film, characterized in that the aforementioned metal compound contains at least one crosslinking group represented by the following general formulas (a-1) to (a-4), (b-1) to (b-4), and (c-1) to (c-3). 【Chemistry 1】 (In general formulas (a-1) to (a-4), R ａ (where is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.) 【Chemistry 2】 (In general formulas (b-1) to (b-4), R ｂ R is a hydrogen atom or a methyl group, and in the same formula they may be the same or different from each other. ｃ (where * represents a hydrogen atom, a substituted or unsubstituted saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and * represents a bond.) 【Transformation 3】 (In general formulas (c-1) to (c-3), Y １ R is a divalent organic group having 1 to 20 carbon atoms, R is a hydrogen atom, a substituted or unsubstituted saturated or unsaturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, R １ This refers to an organic group represented by the following general formula (1) in which a protecting group is removed by the action of either an acid, heat, or both, generating one or more hydroxyl groups or carboxyl groups, where * represents a bond. 【Chemistry 4】 (In general formula (1), R ２ * is an organic group whose protecting group is removed by the action of acid, heat, or both, and * is Y １ (This represents the connection point.)

2. The method for forming a resist underlayer film according to claim 1, characterized in that the oxygen concentration is 0.1 volume% or less.

3. The method for forming a resist underlayer film according to claim 1, characterized in that the temperature is 500°C or higher and 600°C or lower.

4. The method for forming a resist underlayer film according to claim 1, characterized in that the metal contained in the metal compound is titanium, zirconium, hafnium, or a combination thereof.

5. The method for forming a resist underlayer film according to claim 1, characterized in that the aforementioned metal compound further includes a ligand derived from a silicon compound represented by the following general formula (2). 【Transformation 5】 (In general formula (2), R ３Ａ , R ３Ｂ and R ３Ｃ is any one of organic groups having 2 to 30 carbon atoms and having a crosslinking group of a structure represented by the following general formulas (d-1) to (d-3), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms.)) 【Transformation 6】 (In general formulas (d-1) to (d-3), R ３ (where is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, q represents 0 or 1, and * represents a bond.)

6. A method for forming a pattern on a substrate to be processed, (I-1) A step of forming a resist underlayer film on a substrate to be processed by the resist underlayer film formation method described in any one of claims 1 to 5. (I-2) A step of forming a silicon-containing resist interlayer on the resist underlayer, (I-3) A step of forming a resist upper layer film on the silicon-containing resist interlayer film using a photoresist material. (I-4) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (I-5) A step of transferring the pattern to the silicon-containing resist interlayer by dry etching, using the resist upper layer on which the pattern is formed as a mask. (I-6) A step of transferring the pattern to the resist underlayer film by dry etching using the silicon-containing resist interlayer film on which the pattern has been transferred as a mask, and (I-7) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by having the following features.

7. A method for forming a pattern on a substrate to be processed, (II-1) A step of forming a resist underlayer film on a substrate to be processed by the resist underlayer film formation method described in any one of claims 1 to 5. (II-2) A step of forming an inorganic hard mask interlayer film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film, (II-3) A step of forming an organic thin film on the inorganic hard mask interlayer, (II-4) A step of forming a resist upper layer film on the organic thin film using a photoresist material, (II-5) After pattern exposure of the resist upper layer film, develop it with a developer to form a pattern on the resist upper layer film. (II-6) A step of transferring the pattern to the organic thin film and the inorganic hard mask interlayer film by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (II-7) A step of transferring the pattern to the resist underlayer film by dry etching using the inorganic hard mask interlayer film on which the pattern has been transferred as a mask, and (II-8) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by having the following features.

8. A method for forming a pattern on a substrate to be processed, (III-1) A step of forming a resist underlayer film on a substrate to be processed by the resist underlayer film forming method described in any one of claims 1 to 5. (III-2) A step of forming an organic interlayer on the resist underlayer, (III-3) A step of forming a combination of an inorganic hard mask interlayer selected from a silicon-containing resist interlayer, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film, and an organic thin film on the organic interlayer. (III-4) A step of forming a resist upper layer film on the silicon-containing resist interlayer film or the organic thin film using a photoresist material. (III-5) A step of forming a pattern on the resist upper layer film by pattern exposure followed by development with a developer solution. (III-6) A step of transferring the pattern to a silicon-containing resist interlayer or the organic thin film and the inorganic hard mask interlayer by dry etching, using the resist upper layer film on which the pattern is formed as a mask. (III-7) A step of transferring the pattern to the organic interlayer by dry etching, using the silicon-containing resist interlayer or inorganic hard mask interlayer on which the pattern has been transferred as a mask. (III-8) A step of transferring the pattern to the resist underlayer film by dry etching using the organic interlayer film on which the pattern has been transferred as a mask, and (III-9) A step of processing the substrate to be processed using the resist underlayer film on which the pattern is formed as a mask to form a pattern on the substrate to be processed. A pattern forming method characterized by having the following features.

9. A method for forming a resist underlayer film, A coating step of applying a resist underlayer film formation composition containing metals belonging to the 3rd to 7th periods of Groups 3 to 15 of the periodic table to a substrate, A method for forming a resist underlayer film, characterized by comprising a heating step of heating the coated substrate in an atmosphere with an oxygen concentration of less than 1 volume% at a temperature of 450°C to 800°C.

10. The method for forming a resist underlayer film according to claim 9, characterized in that the resist underlayer film forming composition includes a metal compound having a metal-oxygen covalent bond or a metal compound having a metal-carbon covalent bond.

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