Composition for forming adhesive film and patterning process

Abstract

To provide a composition for forming an adhesive film, which is used to form an adhesive film capable of contributing to sensitivity enhancement while effectively suppressing pattern collapse.SOLUTION: A composition for forming an adhesive film comprising (A) an organic polymer, (B) a metal source, and (C) an organic solvent, wherein the organic polymer (A) is a polymer compound containing one or both of repeating units represented by formula (1) and formula (2), and the metal source (B) is a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi with a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal with a β-diketone.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern rules has been rapidly progressing. In particular, logic devices used in smartphones and the like have been driving miniaturization, and logic devices with a 10 nm node are being mass-produced using a multiple exposure (multi-patterning lithography) process by ArF lithography.

[0003] In the next lithography for the 7 nm node and 5 nm node, problems such as high cost due to multiple exposures and overlay accuracy problems in multiple exposures have become apparent, and the advent of EUV lithography capable of reducing the number of exposures has been expected.

[0004] Extreme ultraviolet light (EUV) with a wavelength of 13.5 nm has a wavelength that is 1 / 10 or less shorter than that of an ArF excimer laser with a wavelength of 193 nm. Therefore, EUV lithography is expected to have high contrast of light and high resolution. Since EUV has a short wavelength and a high energy density, an acid generator is sensitized by a small amount of photons. The number of photons in EUV exposure is said to be 1 / 14 of that in ArF exposure. In EUV exposure, a phenomenon in which line width roughness (LWR) and critical dimension uniformity (CDU) of holes deteriorate due to photon variation has been regarded as a problem (Non-Patent Document 1). Furthermore, the possibility of uneven distribution and aggregation of the base polymer and acid generator, and the influence of acid diffusion generated from the acid generator have also been pointed out.

[0005] As a countermeasure, for example, it is possible to reduce the LWR by lowering the post-exposure bake (PEB) temperature, but the sensitivity of the EUV resist will decrease. Furthermore, increasing the amount of quencher added also reduces the LWR, but this method also results in decreased sensitivity. In order to put EUV resist into practical use, it is necessary to break the trade-off relationship between sensitivity and LWR.

[0006] In order for EUV lithography to be put into practical use as a mass production process for semiconductor devices, many issues need to be solved. Among them, the characteristic that particularly requires improvement is to increase the sensitivity while maintaining the LWR. In Patent Document 1, a method of forming an underlayer film containing a sensitizer that absorbs EUV light and generates secondary electrons has been reported. In Patent Document 2, it has been reported that a thermosetting silicon-containing material containing iodine can contribute to improving the sensitivity while maintaining the LWR of the upper layer resist. However, in the above material design, the introduction rate of elements with high light absorption is limited, and it is considered that a material design that contributes more to improving the sensitivity of the resist is required.

[0007] Regarding the above problems, a method of introducing a metal element with a large EUV light absorption coefficient into the resist underlayer film can be considered. In Patent Document 3, a composition of a spin-on material containing metal oxide nanoparticles and an organic polymer has been reported. Although the pattern formation evaluation of the EUV resist is not described, it is assumed that an underlayer film containing a large amount of a metal element with high light absorption can be formed. However, since the film formed using metal nanoparticles has crystallinity, when nanoparticles are used for the resist underlayer film material, there is a risk of deteriorating the line width roughness (LWR) of the pattern when the substrate to be processed is etched.

[0008] In Patent Document 4, a resist composition containing a polymer having a repeating unit having a carboxyl group or phenolic hydroxyl group substituted with an acid-labile group, an acid generator, and a carboxylate or β-diketone complex of various metals has been proposed. In this case, the acid generated from the acid generator is trapped by ion-exchanging with the carboxylate or β-diketone complex of various metals. The carboxylate or β-diketone complex of a metal functions as a quencher for an acid catalyst and is effective for controlling acid diffusion, but does not actively improve sensitivity. A breakthrough for controlling acid diffusion while increasing sensitivity has been desired.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0010]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention has been made in view of the above circumstances, and is an adhesion film forming material for an adhesion film formed between a silicon-containing intermediate film and a resist upper layer film, and can contribute to improving sensitivity while effectively suppressing pattern collapse. An object is to provide an adhesion film forming composition used for forming an adhesion film, and a pattern forming method using this composition.

Means for Solving the Problems

[0012] In order to solve the above problems, in the present invention, A composition for forming an adhesion film formed between a silicon-containing intermediate film and an upper resist film, The composition contains (A) an organic polymer, (B) a metal source, and (C) an organic solvent, and The (A) organic polymer is a high molecular compound containing one or both of the repeating units represented by the following formulas (1) and (2), The (B) metal source is a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal and β-diketones. A composition for forming an adhesion film is provided. [Chemical formula] (In the formula, R1 is a hydrogen atom or a methyl group, R2 is a monovalent organic group having 2 to 20 carbon atoms containing a heterocyclic structure, and R3 is a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms.)

[0013] With such a composition for forming an adhesion film, while maintaining the LWR of the upper resist, it can contribute to improving the sensitivity while effectively suppressing pattern collapse, and can form an adhesion film having excellent adhesion to the upper resist film.

[0014] Further, it is preferable that the heterocyclic structure of R2 in the formulas (1) and (2) is a heterocyclic structure containing an oxygen atom.

[0015] By using such a composition for forming an adhesion film, it becomes possible to improve the adhesion to the resist pattern and prevent the collapse of fine patterns.

[0016] Further, it is preferable that R2 in the formulas (1) and (2) is a monovalent organic group containing a group selected from the following formulas (R2-1) to (R2-3). [Chemical formula] (In the formula, R4 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the dashed line indicates a bond.)

[0017] Further, it is preferable that the (A) organic polymer is a high molecular compound containing any one of the repeating units represented by the following formula (3a) or formula (3b). [Chemical formula] (In the formula, R F1 is a monovalent organic group having 1 to 20 carbon atoms containing at least one F atom, R F2 is an F atom or a monovalent organic group having 1 to 10 carbon atoms containing one or more F atoms, R1 is the same as in the above formula (1), and n represents 1 to 5.)

[0018] By containing such a repeating unit, an organic polymer having excellent adhesiveness is likely to be unevenly distributed on the surface layer of the adhesion film, which is more preferable.

[0019] Further, it is preferable that the (A) organic polymer is a high molecular compound having a weight average molecular weight of 6,000 to 50,000.

[0020] Further, it is preferable that the (A) organic polymer is a high molecular compound having a dispersity represented by weight average molecular weight / number average molecular weight of 3.0 or less.

[0021] By setting the weight average molecular weight and / or dispersity of the high molecular compound contained in the composition for forming an adhesion film within such a range, excellent film-forming properties can be obtained, and the generation of sublimates during heat curing can be suppressed to prevent contamination of the apparatus.

[0022] Further, it is preferable that the (B) metal source is a salt of the metal and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms.

[0023] With such a composition for forming an adhesion film, an adhesion film that can contribute to improving the sensitivity while maintaining the LWR of the upper-layer resist can be formed.

[0024] Further, it is preferable that the (B) metal source has a structure represented by the following formula (B-1). [Chemical formula] (In the formula, M is selected from any of Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi; R1 is a monovalent organic group having 1 to 30 carbon atoms; and n is an integer of 1 to 4.)

[0025] With such a composition for forming an adhesion film, an adhesion film that can contribute to improving the sensitivity while maintaining the LWR of the upper-layer resist can be formed.

[0026] At this time, it is preferable that R1 in the formula (B-1) is a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms.

[0027] With such a (B) metal source, when used in the composition for forming an adhesion film, the solubility in an organic solvent becomes good, the film-forming property is excellent, and an adhesion film with few defects can be formed.

[0028] At this time, it is preferable that R1 in the formula (B-1) is a branched alkyl group having 3 to 10 carbon atoms.

[0029] With such a (B) metal source, when used in the composition for forming an adhesion film, the solubility in an organic solvent becomes good, the film-forming property is excellent, and an adhesion film with few defects can be formed.

[0030] Further, it is preferable that the metal of the (B) metal source is Sn.

[0031] With such a composition for forming an adhesion film, an adhesion film that can contribute to improving the sensitivity while maintaining the LWR of the upper-layer resist can be formed.

[0032] Furthermore, the composition for forming an adhesion film of the present invention preferably contains at least one or more of (D) a thermal acid generator, (E) a photoacid generator, (F) a crosslinking agent, and (G) a surfactant.

[0033] By the presence or absence and selection of these various additives, it becomes possible to finely adjust the performance according to customer requirements in terms of film-forming properties, reduction of sublimates, and further various properties of resist patterning, which is practically preferable.

[0034] It is preferable that the organic solvent (C) is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher ((C-1) high-boiling solvent).

[0035] By including such a high-boiling solvent, sufficient thermal fluidity can be obtained during film formation. Therefore, when forming an adhesion film, it is possible to highly achieve both the pattern adhesion of the (A) organic polymer and the etching selectivity of the (B) metal source without forming a sea-island structure.

[0036] In addition, in the present invention, a method for forming a pattern on a substrate to be processed, (I-1) a step of forming a resist underlayer film on the substrate to be processed, (I-2) a step of forming a silicon-containing resist intermediate film on the resist underlayer film, (I-3) a step of forming an adhesion film by applying the above composition for forming an adhesion film on the silicon-containing resist intermediate film and then performing heat treatment, (I-4) a step of forming a resist upper layer film on the adhesion film using a photoresist material, (I-5) a step of forming a pattern on the resist upper layer film by performing pattern exposure on the resist upper layer film and then developing with a developer, (I-6) a step of transferring the pattern to the adhesion film by dry etching using the resist upper layer film on which the pattern is formed as a mask, (I-7) a step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the adhesion film on which the pattern is formed as a mask, (I-8) A step of transferring a pattern onto the resist lower layer film by dry etching using the silicon-containing resist intermediate film onto which the pattern has been transferred as a mask, and (I-9) A step of transferring a pattern onto the substrate to be processed by dry etching using the resist lower layer film onto which the pattern has been transferred as a mask, provided is a pattern forming method having the above steps.

[0037] By the above pattern forming method using a four-layer resist process, a fine pattern can be formed on a workpiece (substrate to be processed).

[0038] Further, in the present invention, a method for forming a pattern on a substrate to be processed, comprising: (II-1) A step of forming a resist lower layer film on the substrate to be processed, (II-2) A step of forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist lower layer film, (II-3) A step of forming an adhesion film by applying the above composition for forming an adhesion film on the inorganic hard mask intermediate film and then performing heat treatment, (II-4) A step of forming a resist upper layer film using a photoresist material on the adhesion film, (II-5) A step of forming a pattern on the resist upper layer film by pattern exposure and then developing with a developer, (II-6) A step of transferring a pattern onto the adhesion film by dry etching using the resist upper layer film on which the pattern has been formed as a mask, (II-7) A step of transferring a pattern onto the inorganic hard mask intermediate film by dry etching using the adhesion film on which the pattern has been formed as a mask, (II-8) A step of transferring a pattern onto the resist lower layer film by dry etching using the inorganic hard mask intermediate film onto which the pattern has been transferred as a mask, and (II-9) A step of transferring a pattern onto the substrate to be processed by dry etching using the resist lower layer film onto which the pattern has been transferred as a mask, provided is a pattern forming method having the above steps.

[0039] By the pattern formation method using the above four-layer resist process, a fine pattern can be formed on a workpiece with high precision.

[0040] In addition, in the step (I-5), it is preferable to perform the pattern exposure using EUV light.

[0041] In addition, in the step (II-5), it is preferable to perform the pattern exposure using EUV light.

[0042] Since the composition for forming an adhesion film of the present invention contains metal atoms with high light absorption, in EUV lithography, an adhesion film that can contribute to improving sensitivity while maintaining the LWR of the upper layer resist can be formed. In addition, since it contains an organic polymer having excellent adhesion to the resist upper layer film, pattern collapse can be effectively suppressed, it is suitable for photolithography of the resist upper layer film, and it is possible to transfer the resist upper layer film pattern to the workpiece with high precision.

Advantages of the Invention

[0043] As described above, the present invention provides a composition for forming an adhesion film that has high adhesion to a resist upper layer film, has an effect of suppressing collapse of a fine pattern, and can contribute to improving sensitivity while maintaining the LWR of the upper layer resist in EUV lithography. In addition, this composition for forming an adhesion film has high adhesion, has an effect of suppressing collapse of a fine pattern, and gives a pattern shape of a resist upper layer film with high rectangularity to a workpiece, so it is extremely useful in a multilayer resist process.

Brief Description of the Drawings

[0044]

Fig. 1

Embodiments for Carrying Out the Invention

[0045] As described above, in the fine patterning process in the semiconductor device manufacturing process, there has been a demand for the development of a composition for forming an adhesion film that has high adhesion to the resist upper layer film and provides an adhesion film that suppresses the collapse of fine patterns, and that can contribute to improving the sensitivity while maintaining LWR in EUV lithography, and a pattern forming method using the composition.

[0046] As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by a composition for forming an adhesion film containing a polymer compound having a specific structure and a metal source, and a pattern forming method using this composition for forming an adhesion film, and have completed the present invention.

[0047] That is, the present invention is a composition for forming an adhesion film for forming an adhesion film formed between a silicon-containing intermediate film and a resist upper layer film, the composition comprising: (A) an organic polymer; (B) a metal source; and (C) an organic solvent, and the (A) organic polymer is a polymer compound containing one or both of the repeating units represented by the following formulas (1) and (2), and the (B) metal source is a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal and β-diketones.

Chemical formula

[0048] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0049] <Composition for forming adhesion film> The present invention relates to an adhesion film forming composition for forming an adhesion film formed between a silicon-containing intermediate film and a resist upper layer film, the composition comprising: (A) an organic polymer, (B) a metal source, and (C) an organic solvent, and the (A) organic polymer is a high molecular compound containing one or both of the repeating units represented by the following formula (1) and formula (2), and the (B) metal source is a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal and β-diketones.

Chemical formula

[0050] For such an adhesion film forming composition, the metal salt structure decomposes by heat treatment and metal ions are desorbed to form a metal oxide, so that an adhesion film with a high metal content can be provided. Since the film contains many metal atoms with a large light absorption, it has the characteristic that the sensitization effect by secondary electrons generated during exposure can be expected in EUV lithography. Furthermore, since the above metal atoms have a large atomic weight, they have a high effect of suppressing acid diffusion from the upper resist into the adhesion film, and have the characteristic that high sensitivity can be achieved while maintaining the LWR performance originally possessed by the resist upper layer film. In addition, since it has an organic polymer containing any of the repeating units represented by formula (1) or formula (2) and having excellent adhesion to the resist upper layer film pattern, it is effective in suppressing the collapse of fine patterns, and in lithography using EUV light, an extremely effective pattern forming method can be provided.

[0051] In the composition for forming an adhesion film of the present invention, as the (A) organic polymer, (B) metal source, and (C) organic solvent, each one kind of component may be used alone, or two or more kinds of components may be used in combination. Further, the composition for forming an adhesion film may contain components other than the above components (A), (B), and (C). Each component will be described below.

[0052] [(A) Organic Polymer] The (A) organic polymer contained in the composition for forming an adhesion film of the present invention is a high molecular compound containing one or both of the repeating units represented by the following general formula (1) and the repeating unit represented by the following general formula (2).

[0053] [Chemical formula] (In the formula, R1 is a hydrogen atom or a methyl group, R2 is a monovalent organic group having 2 to 20 carbon atoms containing a heterocyclic structure, and R3 is a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms.)

[0054] For such an (A) organic polymer, since the surface energy is lower than that of the (B) metal source, when an adhesion film is formed, it is possible to highly achieve both the pattern adhesion of the (A) organic polymer and the etching selectivity of the (B) metal source without forming a sea-island structure.

[0055] It is preferable that the above R3 is a hydrogen atom.

[0056] It is preferable that the heterocyclic structure contained in R2 of the repeating units represented by the above general formula (1) and formula (2) is a heterocyclic structure containing an oxygen atom.

[0057] By including such a heterocyclic structure, higher adhesion with the resist pattern can be obtained, which is more effective for preventing the collapse of the fine resist pattern.

[0058] It is preferable that the above R2 is a monovalent organic group containing a group selected from the following formulas (R2-1) to (R2-3).

[0059] [Chemical formula] (In the formula, R4 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the broken line indicates a bond.)

[0060] By including such a heterocyclic structure, the epoxy or oxetane structure undergoes a ring-opening reaction during heat film formation to cure the film. In addition, the hydroxyl groups generated by this ring-opening reaction also contribute to improving the adhesion to the resist upper layer film.

[0061] In the above (R2-3), R4 is preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably an ethyl group.

[0062] Specific examples of the repeating units represented by the above formulas (1) and (2) can preferably include the following structures.

[0063] [Chemical formula] (R1 and R4 are the same as above.)

[0064] Note that the repeating units represented by the above general formula (1) and the above general formula (2) may be contained only one kind in the high molecular compound of the (A) organic polymer, or may be contained two or more kinds.

[0065] The content rate of the repeating units represented by the above general formula (1) and the above general formula (2) in the high molecular compound contained in the above (A) organic polymer is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more with respect to all repeating units.

[0066] In addition, the content rate of the repeating units represented by the above general formula (1) and formula (2) in the high molecular compound contained in the above (A) organic polymer is preferably 95 mol% or less, and more preferably 90 mol% or less with respect to all repeating units.

[0067] By setting the repeating units represented by the general formula (1) and the general formula (2) to such a content ratio, the polarity of the polymer compound is adjusted, and the adhesion to the resist pattern becomes good. Further, since the epoxy or oxetane structure of the general formulas (1) and (2) undergoes a ring-opening reaction during heat-assisted film formation to cure the film, a dense adhesion film can be formed, and it becomes possible to prevent intermixing between the adhesion film and the resist upper layer film. As a result, generation of residues in the space portion of the pattern can be prevented, and a pattern with high rectangularity can be obtained. Therefore, in the above (A) organic polymer, it is preferable that the content ratio of the repeating units represented by the general formula (1) and the general formula (2) is 30 mol% or more and 95 mol% or less, particularly 50 mol% or more and 90 mol% or less, with respect to all the repeating units.

[0068] It is preferable that the (A) organic polymer is a polymer compound further containing any one of the repeating units represented by the following formula (3a) or formula (3b).

[0069]

Chemical formula

[0070] It is more preferable that the polymer compound contains any one of the repeating units represented by the formula (3a) or formula (3b) because the (A) organic polymer tends to be unevenly distributed on the surface layer of the adhesion film.

[0071] Specific examples of the repeating units represented by the formula (3a) and the formula (3b) can preferably include the following structures.

[0072]

Chemical formula

[0073] In addition, the repeating units represented by the general formula (3a) and the general formula (3b) may be contained only in one kind in the (A) organic polymer, or may be contained in two or more kinds.

[0074] For the polymer compound which is the above (A) organic polymer, with respect to all the repeating units, the content of the repeating units represented by the general formula (1) and the general formula (2) is more preferably 30 mol% or more and 95 mol% or less, 50 mol% or more and 90 mol% or less. The content of the repeating units represented by the general formula (3a) and the general formula (3b) is more preferably 5 mol% or more and 70 mol% or less, 10 mol% or more and 50 mol% or less.

[0075] It is preferable that the (A) organic polymer is a polymer compound further containing any of the repeating units represented by the following formula (4a).

[0076] [Chemical formula] (In the formula, R 01 is a hydrogen atom or a methyl group, R 02 is an alkyl group having 1 to 3 carbon atoms, m is an integer of 1 or 2, n represents an integer of 0 to 4, and m + n is an integer of 1 or more and 5 or less. X represents a single bond or an alkylene group which may contain an oxygen atom having 1 to 10 carbon atoms.)

[0077] In the general formula (4a), R 01 is a hydrogen atom or a methyl group, R 02 is an alkyl group having 1 to 3 carbon atoms, m is an integer of 1 or 2, n represents an integer of 0 to 4, m + n is an integer of 1 or more and 5 or less, preferably, m is an integer of 1 or 2, n is an integer of 0 or 1, and m + n is an integer of 1 or more and 3 or less. More preferably, m is 1, n is 0, and m + n is 1.

[0078] In the general formula (4a), X is a single bond or an alkylene group which may contain an oxygen atom and has 1 to 10 carbon atoms. The oxygen atom in X can form a carbonyl group, a hydroxyl group, or an ether bond. For example, an ester bond is an alkylene group containing an oxygen atom with 1 carbon atom.

[0079] Specific examples of X include, but are not limited to, the following.

[0080]

Chemical formula

[0081] R in the general formula (4a) 02 Examples include a methyl group, an ethyl group, a propyl group, and an isopropyl group. From the perspective of adhesion to the resist upper layer film, a methyl group is preferred.

[0082] Specific examples of the resin represented by the general formula (4a) include, but are not limited to, the following. In the following formula, R 01 is the same as described above.

[0083]

Chemical formula

[0084]

Chemical formula

[0085] For a composition for forming an adhesion film containing these resins, an adhesion film with excellent film-forming properties can be formed on the silicon-containing resist intermediate film.

[0086] In addition, the above (A) organic polymer preferably further has a repeating unit represented by the following general formula (A-1).

[0087]

Chemical formula

[0088] In the general formula (A-1) above, R5 is a single bond or a divalent linking group having 2 to 10 carbon atoms containing an ester group. Specifically, as R5, a single bond, -CO2CH2-, -CO2CH2CH2-, -CO2CH2CH2CH2-, -CO2CH(CH3)-, -CO2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2CH2CH2CH2CH2-, -CO2CH2CH2O-, -CO2CH2CH2OCH2CH2O-, -CO2CH2CH2OCH2CH2OCH2CH2O-, etc. can be exemplified. Among these, in particular, -CO2CH2-, -CO2CH2CH2-, -CO2CH2CH2CH2-, -CO2CH2CH2CH2CH2-, -CO2CH2CH2CH2CH2CH2- are preferable.)

[0089] Specific examples of R6 in the repeating unit represented by the general formula (A-1) above include, but are not limited to, the following structures. The dashed line indicates a bond.)

[0090] [Chemical formula]

[0091] [Chemical formula]

[0092] [Chemical formula]

[0093] When forming an adhesion film from a composition for forming an adhesion film containing a polymer compound containing a repeating unit represented by the above general formula (A-1), due to the action of heat and / or an acid generated from an acid generator described below, the elimination decomposition reaction of the tertiary alkyl group R6 proceeds to generate a carboxylic acid. Due to the polarity of this carboxylic acid, the adhesion to the resist pattern is improved, the rectangularity of the pattern is improved, or the generation of residues in the space portion of the pattern is prevented.

[0094] In addition, the generated carboxylic acid may undergo a ring-opening addition reaction with the repeating units represented by the above general formulas (1) and (2) to form a hydroxyester crosslinked structure. A typical example of the reaction is shown below. In the following formula, the state where R6 in the repeating unit (A-1) has been eliminated to form a carboxylic acid is (A-2), and the state where a hydroxyester crosslinked structure is formed by a ring-opening addition reaction with (1”) which is an example of the above general formulas (1) and (2) is (A-3). Also, the portion surrounded by the dotted line is the hydroxyester crosslinked structure formed by this reaction.

[0095]

Chemical formula

[0096] The formation of this hydroxyester crosslinked structure is a crosslinking reaction and promotes the curing of the adhesion film. By sufficient curing, a dense film is formed, and the intermixing between the adhesion film and the resist upper layer film is prevented, so that residues in the space portion of the pattern can be prevented, and a pattern with high rectangularity can be obtained.

[0097] In addition, the above hydroxyester crosslinked structure is a polar group and has an interaction with the resist pattern. Therefore, the presence of the repeating unit (A-1) also contributes to preventing the collapse of the resist pattern.

[0098] In addition, the repeating unit represented by the general formula (A-1) may be contained only in one kind in the high molecular compound of the (A) organic polymer, or may be contained in two or more kinds.

[0099] When the high molecular compound of the (A) organic polymer contains the repeating unit represented by the above formula (A-1), the content of the repeating unit represented by the formula (A-1) with respect to all the repeating units of the high molecular compound of the (A) organic polymer is preferably 1 mol% or more and 30 mol% or less, and preferably 5 mol% or more and 15 mol% or less.

[0100] The weight average molecular weight of the (A) organic polymer is preferably 6,000 to 50,000, and the dispersity represented by the weight average molecular weight / number average molecular weight is preferably 3.0 or less.

[0101] Here, the "weight average molecular weight" is a value measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent and polystyrene as a standard substance. When the weight average molecular weight and dispersity of the high molecular compound used for the (A) organic polymer contained in the adhesive film-forming composition are in such ranges, excellent film-forming properties can be obtained during spin coating, and the generation of sublimates can be suppressed during heat curing, so that contamination of the apparatus can be prevented. In particular, when forming an adhesive film as a resist intermediate film, if the composition contains components with a low molecular weight and high volatility, the film thickness distribution within the surface of the substrate to be processed is likely to vary. However, if the molecular weight and dispersity of the high molecular compound used are set as described above and the amount of low molecular weight components in the composition is controlled, the film thickness distribution within the surface of the substrate to be processed can be suppressed to be small. Therefore, the weight average molecular weight of the high molecular compound contained in the (A) organic polymer used in the adhesive film-forming composition of the present invention is preferably 6,000 to 50,000, particularly preferably 8,000 to 40,000. The dispersity is preferably 3.0 or less.

[0102] The content rate of the (A) organic polymer contained in the composition for forming an adherent film is preferably 1 to 50 parts by mass, more preferably 5 to 30 parts by mass, with respect to 100 parts by mass of the (B) metal source.

[0103] With such a content rate, it is possible to further highly balance the pattern adhesion of the (A) organic polymer and the etching selectivity of the (B) metal source.

[0104] As a method for synthesizing the high molecular compound of the (A) organic polymer, for example, there is a method in which monomers having polymerizable unsaturated bonds corresponding to each repeating unit are mixed, and a radical polymerization initiator is added in a solvent and heated for polymerization.

[0105] The polymerization conditions can be variously selected according to the monomers used, the target molecular weight, etc., and are not particularly limited. Specifically, as the solvent used during polymerization, toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, 2-butanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, cyclohexanone, γ-butyrolactone, ethyl acetate, butyl acetate, diacetone alcohol, etc. can be exemplified. Examples of the radical polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. Also, during polymerization, thiols such as octanethiol and 2-mercaptoethanol may be added as a chain transfer agent. The polymerization reaction can preferably be carried out by heating to 40°C to the boiling point of the reaction solvent. The reaction time is preferably 0.5 to 100 hours, more preferably 1 to 48 hours.

[0106] For example, by using the compounds having polymerizable double bonds represented by the following general formulas (1'), (2'), and (A-1') as monomers and performing the polymerization as described above, a high molecular compound containing the repeating units represented by the above general formulas (1), (2), and (A-1) can be synthesized.

[0107] [Chemical formula] (In the formula, R1 to R3, R5 to R6, and R1 ’ are the same as described above.)

[0108] At the time of polymerization, after mixing all the raw materials, heating may be performed, or the remaining raw materials may be individually or mixed and added all at once or gradually to a part of the raw materials that have been pre-heated. For example, a polymerization method in which only the polymerization solvent is heated and the monomer solution and the polymerization initiator solution are gradually added separately thereto is particularly preferable because a relatively homogeneous polymer compound can be obtained and abnormal reactions such as a runaway reaction can be prevented.

[0109] The polymer compound solution obtained as described above may be directly blended into the composition for forming an adherent film, or if necessary, it may be purified using conventional methods such as crystallization, liquid separation, filtration, and concentration to remove residual monomers, residual solvents, reaction by-products, and other impurities. When purifying the polymer compound, a crystallization method in which a poor solvent such as water, hydrous alcohol, or saturated hydrocarbon is added to the solution of the polymer compound and the resulting precipitate is collected by filtration, or a liquid separation method in which the poor solvent layer is separated and removed is suitable, and among these, the liquid separation method is particularly suitable. When the polymer compound is purified by the liquid separation method, low molecular weight components in the polymer compound solution can be efficiently removed, so that the generation of sublimates is reduced when forming an adherent film from the composition for forming adhesiveness containing this polymer compound, and as a result, contamination of the film forming apparatus can be prevented.

[0110] <(B) Metal source> The (B) metal source contained in the composition for forming an adherent film of the present invention is a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal and β-diketones.

[0111] Preferred carboxylates can be exemplified as follows.

[0112] [Chemical formula] (In the formula, R 1 is a hydrogen atom which may be the same or different, a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, preferably 2 to 20 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, preferably 2 to 20 carbon atoms, or an aryl group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, and these may have a hydroxy group, an ether group, an ester group, an amino group, an amide group, a sulfonate ester group, a halogen atom, a cyano group, a nitro group, a carbonate group, a carbamate group, a thiol group, a sulfide group, a thioketone group, or a heteroaromatic ring. R 2 is a single bond, or a linear, branched or cyclic alkylene group, alkenylene group, alkynylene group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, or an arylene group having 6 to 30 carbon atoms, preferably 6 to 20 carbon atoms, and these may have a hydroxy group, an ether group, an ester group, an amino group, an amide group, a sulfonate ester group, a halogen atom, a cyano group, a nitro group, a carbonate group, a carbamate group, a thiol group, a sulfide group, a thioketone group, or a heteroaromatic ring. R 3 is a group obtained by removing one hydrogen atom from the alkylene group, arylene group, alkenylene group, or alkynylene group of the above R 2 . R 4 is a group obtained by removing two hydrogen atoms from the alkylene group, arylene group, alkenylene group, or alkynylene group of the above R 2 .)

[0113] The carboxylic acid ions for forming the carboxylate in the above general formula are specifically exemplified below.

[0114]

Chemical formula

[0115]

Chemical formula

[0116]

Chem.

[0117]

Chem.

[0118]

Chem.

[0119]

Chem.

[0120]

Chem.

[0121]

Chem.

[0122]

Chem.

[0123]

Chem.

[0124]

Chem.

[0125] The carboxylic acid ions for forming the carboxylate are preferably those in which the larger the number of carbon atoms in the carboxylic acid, the more easily soluble in the organic solvent. Also, if the number of carbon atoms in the carboxylic acid is not too large, the shrinkage amount when forming the resist film becomes small, and the outgas component amount also becomes small. From the above viewpoints, the carboxylic acid ions preferably have a linear or branched alkyl group having 3 to 10 carbon atoms.

[0126] Preferred β-diketone complexes can be exemplified as follows.

[0127] [Chemical formula] (In the formula, R 1 , R 2 are the same or different linear, branched or cyclic alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, or aryl groups having 6 to 20 carbon atoms, and these may have a hydroxy group, an alkoxy group, an ether group, an ester group, an amino group, an amide group, a sulfonic acid ester group, a halogen atom, a cyano group, a nitro group, a carbonate group, a carbamate group, a thiol group, a sulfide group, a thioketone group, or a heteroaromatic ring.)

[0128] The β-diketones in the above general formula are substituted or unsubstituted acetylacetones, and specifically, they are exemplified as follows.

[0129] [Chemical formula]

[0130] [Chemical formula]

[0131] [Chemical formula]

[0132] [Chemical formula]

[0133]

Chem.

[0134]

Chem.

[0135] R 1 and R 2 are generally the same β-diketones, but may be different as described in JP-A-2004-175755. R 1 and R 2 Acetylacetone in which both are methyl groups is the most common, but it has the drawback of poor solubility in organic solvents. R 1 and R 2 The total number of carbon atoms of is preferably 3 or more, more preferably 4 or more.

[0136] The hydrogen atoms of acetylacetone are substituted, and the larger the number of carbon atoms of the substituent, the easier it is to dissolve in an organic solvent, which is preferable. The larger the number of carbon atoms of the substituent, the more the uniformity of the film thickness improves when the composition for forming an adherent film is spin-coated. Also, if the number of carbon atoms of the carboxylic acid is not too large, the shrinkage amount when forming an adherent film decreases, and the amount of outgas components also decreases.

[0137] Acetylacetone forms a complex with a metal by enolization as shown below.

[0138]

Chem.

[0139] The (B) metal source used in the composition for forming an adhesion film of the present invention is preferably a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms. Specifically, it more preferably has a structure represented by the following formula (B-1).

[0140]

Chemical formula

[0141] From the viewpoints of solubility in an organic solvent, the amount of outgas components during baking, and productivity, R1 in the above formula (B-1) is more preferably a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and even more preferably a branched alkyl group having 3 to 10 carbon atoms.

[0142] From the viewpoint of improving the exposure sensitivity of the resist upper layer film in EUV lithography, M in the above formula (B-1) is more preferably Ti, Hf, Sn, or Bi, and even more preferably Sn.

[0143] The content of the (B) metal source in the composition for forming an adhesion film is preferably 1 to 200 parts by mass, more preferably 5 to 100 parts by mass, and even more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the (A) organic polymer. When the content of the (B) metal source is 1 part by mass or more, the contribution to improving the exposure sensitivity of the resist upper layer film in EUV lithography becomes sufficient. When the content of the (B) metal source is 200 parts by mass or less, the adhesion to the resist upper layer film pattern becomes sufficient, and the collapse of the pattern of the resist upper layer film can be suppressed. These can be appropriately adjusted according to the required characteristics when used in the composition for forming an adhesion film.

[0144] <(C) Organic solvent> As the (C) organic solvent that can be used in the composition for forming an adhesion film of the present invention, as long as it can dissolve or disperse the above-mentioned (A) organic polymer, (B) metal source, and, when included, the following (D) thermal acid generator, (E) photoacid generator, (F) crosslinking agent, and (G) surfactant, and other additives, there is no particular limitation.

[0145] Specifically, they are monoalkyl ethers such as ethylene glycol, diethylene glycol, and triethylene glycol, and monoalkyl ethers such as propylene glycol and dipropylene glycol. Specifically, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, diacetone alcohol, 2-heptanone, cyclopentanone, cyclohexanone, and γ-butyrolactone, or a mixture containing one or more of these is preferably used.

[0146] The blending amount of the organic solvent is preferably 200 to 10,000 parts, more preferably 250 to 5,000 parts, relative to 100 parts by mass of the (B) metal source.

[0147] <(C-1) High-boiling solvent> In the composition for forming an adhesion film of the present invention, the (C) organic solvent may contain a (C-1) high-boiling solvent.

[0148] The (C-1) high-boiling organic solvent can be one or more organic solvents having a boiling point of 180 degrees (°C) or higher.

[0149] For example, as the (C) organic solvent, 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 ((C-1) high-boiling solvent) may be used.

[0150] (C-1) As the high-boiling solvent, there are no particular restrictions as long as it can dissolve or disperse each component of the composition for forming an adhesion film of the present invention, and examples include hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc. Specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3 - hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol - n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4 - butanediol diacetate, 1,3 - butylene glycol diacetate, 1,Examples thereof 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, dibutyl adipate, triethanolamine, etc., and these may be used alone or in combination.

[0151] (C - 1) The high - boiling solvent may be appropriately selected from, for example, the above - mentioned ones according to the temperature for heat - treating the composition for forming an adhesion film of the present invention. The boiling point of the high - boiling solvent is preferably 180°C to 300°C, and more preferably 200°C to 300°C. With such a boiling point, there is no fear that the volatilization during baking (heat - treatment) will be too fast, so that the occurrence of defects due to drying during film formation can be suppressed. Also, with such a boiling point, it will not remain in the film without volatilizing after baking, so there is no fear of adversely affecting the film physical properties such as etching resistance.

[0152] Also, when using the (C - 1) high - boiling solvent, the blending amount is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the organic solvent having a boiling point of less than 180°C. With such a blending amount, sufficient heat fluidity can be imparted during baking, and it will not remain in the film and lead to deterioration of film physical properties such as etching resistance, so it is preferable.

[0153] <Other Components> The above composition for forming an adhesion film may optionally contain at least one or more of (D) a thermal acid generator, (E) a photoacid generator, (F) a cross - linking agent, and (G) a surfactant.

[0154] Hereinafter, components other than the above (A) organic polymer, (B) metal source, and (C) organic solvent that can be contained in the composition for forming an adhesion film of the present invention will be described.

[0155] [(D) Thermal Acid Generator] In the composition for forming an adhesion film of the present invention, it is preferable to add (D) a thermal acid generator in order to accelerate the crosslinking reaction by heat.

[0156] Examples of the thermal acid generator (D) that can be used in the composition for forming an adhesion film of the present invention include the following general formula (7).

[0157] [Chemical formula] (In the formula, X A - represents a non-nucleophilic counter ion. R 70 , R 71 , R 72 , and R 73 each represent a hydrogen atom or a linear, branched, or cyclic alkyl group, alkenyl group, oxoalkyl group, or oxoalkenyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group, or aryloxoalkyl group having 7 to 12 carbon atoms, and a part or all of the hydrogen atoms of these groups may be substituted by an alkoxy group or the like. Further, R 70 and R 71 , or R 70 , R 71 and R 72 may form a ring, and when forming a ring, R 70 and R 71 , or R 70 , R 71 and R 72 represent an alkylene group having 3 to 10 carbon atoms or a heteroaromatic ring having a nitrogen atom in the formula in the ring.)

[0158] In the above, R 70 , R 71 , R 72 , and R 73They may be the same as or different from each other. Specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, an adamantyl group, and the like.

[0159] Examples of the alkenyl group include a vinyl group, an allyl group, a propenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and the like.

[0160] Examples of the oxoalkyl group include a 2-oxocyclopentyl group, a 2-oxocyclohexyl group, a 2-oxopropyl group, a 2-cyclopentyl-2-oxoethyl group, a 2-cyclohexyl-2-oxoethyl group, a 2-(4-methylcyclohexyl)-2-oxoethyl group, and the like.

[0161] Examples of the oxoalkenyl group include a 2-oxo-4-cyclohexenyl group, a 2-oxo-4-propenyl group, and the like.

[0162] Examples of the aryl group include a phenyl group, a naphthyl group, and alkoxyphenyl groups such as a p-methoxyphenyl group, an m-methoxyphenyl group, an o-methoxyphenyl group, an ethoxyphenyl group, a p-tert-butoxyphenyl group, an m-tert-butoxyphenyl group; alkylphenyl groups such as a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, an ethylphenyl group, a 4-tert-butylphenyl group, a 4-butylphenyl group, a dimethylphenyl group; alkylnaphthyl groups such as a methylnaphthyl group, an ethylnaphthyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group; dialkylnaphthyl groups such as a dimethylnaphthyl group, a diethylnaphthyl group; and dialkoxynaphthyl groups such as a dimethoxynaphthyl group, a diethoxynaphthyl group, and the like.

[0163] Examples of the aralkyl group include a benzyl group, a phenylethyl group, and a phenethyl group.

[0164] Examples of the aryloxoalkyl group include 2-aryl-2-oxoethyl groups such as a 2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0165] Also, R 70 and R 71 , or R 70 , R 71 and R 72When forming a heteroaromatic ring having a nitrogen atom in the ring in the formula, imidazole derivatives (e.g., imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, etc.), pyrazole derivatives, furazan derivatives, pyrroline derivatives (e.g., pyrroline, 2-methyl-1-pyrroline, etc.), pyrrolidine derivatives (e.g., pyrrolidine, N-methylpyrrolidine, pyrrolidinone, N-methylpyrrolidone, etc.), imidazoline derivatives, imidazolidine derivatives, pyridine derivatives (e.g., pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone, 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2-(1-ethylpropyl)pyridine, aminopyridine, dimethylaminopyridine, etc.), pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives, pyrazoline derivatives, pyrazolidine derivatives, piperidine derivatives, piperazine derivatives, morpholine derivatives, indole derivatives, isoindole derivatives, 1H-indazole derivatives, indoline derivatives, quinoline derivatives (e.g., quinoline, 3-quinolinecarbonitrile, etc.), isoquinoline derivatives, cinnoline derivatives, quinazoline derivatives, quinoxaline derivatives, phthalazine derivatives, purine derivatives, pteridine derivatives, carbazole derivatives, phenanthridine derivatives, acridine derivatives, phenazine derivatives, 1,10-phenanthroline derivatives, adenine derivatives, adenosine derivatives, guanine derivatives, guanosine derivatives, uracil derivatives, uridine derivatives, etc. are exemplified.

[0166] The above, X A -Examples of the non-nucleophilic counter ions include halide ions such as chloride ions and bromide ions, fluoroalkyl sulfonates such as triflate, 1,1,1-trifluoroethanesulfonate, and nonafluorobutanesulfonate, aryl sulfonates such as tosylate, benzenesulfonate, 4-fluorobenzenesulfonate, and 1,2,3,4,5-pentafluorobenzenesulfonate, alkyl sulfonates such as mesylate and butanesulfonate, imidic acids such as bis(trifluoromethylsulfonyl)imide, bis(perfluoroethylsulfonyl)imide, and bis(perfluorobutylsulfonyl)imide, methidic acids such as tris(trifluoromethylsulfonyl)methide and tris(perfluoroethylsulfonyl)methide, and furthermore, sulfonates with a fluoro substitution at the α-position represented by the following general formula (8), and sulfonates with fluoro substitutions at the α- and β-positions represented by the following general formula (9).

[0167] [Chemical formula]

[0168] In the above general formula (8), R 81 is a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 23 carbon atoms, an acyl group, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aryloxy group. In the above general formula (9), R 91 is a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0169] Specific examples of the above thermal acid generator can be illustrated below, but are not limited thereto.

[0170] [Chemical formula]

[0171] The (D) thermal acid generator contained in the composition for forming an adhesion film of the present invention can be used alone or in combination of two or more. The addition amount of the thermal acid generator is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the above (A) organic polymer. If it is 0.05 parts by mass or more, the amount of acid generated and the crosslinking reaction will be sufficient, and if it is 30 parts by mass or less, there is little risk of a mixing phenomenon due to the migration of acid to the upper layer resist.

[0172] [(E) photoacid generator] In the composition for forming an adhesion film of the present invention, an (E) photoacid generator can be added in order to appropriately adjust the pattern shape, exposure sensitivity, etc. of the resist upper layer film. The photoacid generator can be used alone or in combination of two or more. As the photoacid generator, for example, those described in paragraphs

[0160] to

[0179] of JP-A-2009-126940 can be used. The addition amount of the photoacid generator is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the above (A) organic polymer. If the addition amount of the photoacid generator is within the above range, the resolution is good, and there is no risk of problems with foreign matters during or after resist development or peeling.

[0173] <(F) crosslinking agent> In addition, an (F) crosslinking agent can also be added to the composition for forming an adhesion film of the present invention in order to enhance the curability and further suppress the intermixing with the resist upper layer film.

[0174] The crosslinking agent is not particularly limited, and various known types of crosslinking agents can be widely used. As an example, melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, and epoxy-based crosslinking agents can be exemplified. The above (F) crosslinking agent can be used alone or in combination of two or more. When adding the crosslinking agent, the addition amount is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, based on 100 parts by mass of the above (A) organic polymer. If the addition amount is 5 parts by mass or more, sufficient curability can be exhibited, and intermixing with the resist upper layer film can be suppressed. On the other hand, if the addition amount is 50 parts by mass or less, there is no risk of deterioration of dry etching resistance due to a low ratio of the (B) metal source in the composition.

[0175] As the melamine-based crosslinking agent, specifically, hexamethoxymethylated melamine, hexabutoxymethylated melamine, their alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified.

[0176] As the glycoluril-based crosslinking agent, specifically, tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, their alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified.

[0177] As the benzoguanamine-based crosslinking agent, specifically, tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, their alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified.

[0178] As the urea-based crosslinking agent, specifically, dimethoxymethylated dimethoxyethyleneurea, its alkoxy and / or hydroxy-substituted products, and their partial self-condensates can be exemplified.

[0179] Specific examples of the β-hydroxyalkylamide-based crosslinking agent include N,N,N’,N’-tetra(2-hydroxyethyl) adipic acid amide.

[0180] Specific examples of the isocyanurate-based crosslinking agent include triglycidyl isocyanurate and triallyl isocyanurate.

[0181] Specific examples of the aziridine-based crosslinking agent include 4,4’-bis(ethyleneiminocarbonylamino) diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl) propionate].

[0182] Specific examples of the oxazoline-based crosslinking agent include 2,2’-isopropylidene bis(4-benzyl-2-oxazoline), 2,2’-isopropylidene bis(4-phenyl-2-oxazoline), 2,2’-isopropylidene bis(4-phenyl-2-oxazoline), 2,2’-methylene bis 4,5-diphenyl-2-oxazoline, 2,2’-methylene bis-4-phenyl-2-oxazoline, 2,2’-methylene bis-4-tert butyl-2-oxazoline, 2,2’-bis(2-oxazoline), 1,3-phenylene bis(2-oxazoline), 1,4-phenylene bis(2-oxazoline), and 2-isopropenyl oxazoline copolymer.

[0183] Specific examples of the epoxy-based crosslinking agent include diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, poly(glycidyl methacrylate), trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0184] Examples of the epoxy-based crosslinking agent and oxetane-based crosslinking agent include, but are not limited to, those shown below.

[0185] [Chemical formula]

[0186] The above compounds can be purchased, but epoxy crosslinking agents and oxetane crosslinking agents can also be obtained by reacting hydroxyl groups with epibromohydrin, 3-bromomethyloxetane, etc. as shown in the following formula. In the following formula, R5 is a substituted or unsubstituted monovalent organic group with 1 to 20 carbon atoms that is saturated or has 2 to 20 carbon atoms and is unsaturated, a substituted or unsubstituted aryl group with 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group with 7 to 31 carbon atoms. Also, it is possible to leave some hydroxyl groups unreacted. At this time, it is preferable that the number of epoxy + oxetane > the number of hydroxyl groups, and more preferably the number of epoxy + oxetane > the number of hydroxyl groups * 2.

[0187] Also, the content of these compounds is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, based on 100 parts by mass of the above-mentioned (B) metal source.

[0188] [Chemical formula]

[0189] Specific examples of the compounds having hydroxyl groups that can be used in the above reaction include, but are not limited to, the following.

[0190] [Chemical formula]

[0191] [(G) Surfactant] In the composition for forming an adhesion film of the present invention, a (G) surfactant can be added to improve the coatability in spin coating. The surfactant can be used alone or in combination of two or more. As the surfactant, for example, those described in paragraphs

[0142] to

[0147] of JP-A-2009-269953 can be used. When adding the surfactant, the addition amount is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the above (A) organic polymer. If it is within such a range, the coatability is surely improved and a thin and uniform adhesion film can be formed.

[0192] [Plasticizer] Further, a plasticizer can be added to the composition for forming an adhesion film of the present invention. The plasticizer is not particularly limited, and various known types of plasticizers can be widely used. As an example, low molecular compounds such as phthalic acid esters, adipic acid esters, phosphoric acid esters, trimellitic acid esters, citric acid esters, polymers such as polyether-based, polyester-based, and polyacetal-based polymers described in JP-A-2013-253227 can be exemplified. The addition amount of the plasticizer is preferably 1 part by mass to 500 parts by mass with respect to 100 parts by mass of the above (A) organic polymer. If the addition amount is within such a range, the pattern embedding and averaging will be excellent.

[0193] <Adhesion film forming method> In the present invention, using the above-described composition for forming an adhesion film, for example, an adhesion film formed between a silicon-containing intermediate film and a resist upper layer film of a multilayer resist film used in lithography can be formed.

[0194] In the method for forming an adhesion film using the composition for forming an adhesion film of the present invention, the above composition for forming an adhesion film is coated on a substrate to be processed by a spin coating method or the like. After spin coating, the solvent is evaporated, and baking (heat treatment) is performed to promote the crosslinking reaction in order to prevent mixing with the resist upper layer film. The baking is preferably performed in the range of 100°C or higher and 450°C or lower for 10 to 600 seconds, more preferably in the range of 200°C or higher and 300°C or lower for 10 to 300 seconds. Considering the influence on device damage and wafer deformation, the upper limit of the heating temperature in the wafer process of lithography is preferably 450°C or lower, more preferably 300°C or lower.

[0195] Also, in the method for forming an adhesion film using the composition for forming an adhesion film of the present invention, the composition for forming an adhesion film of the present invention is coated on a substrate to be processed by the spin coating method or the like as described above, and the composition for forming an adhesion film is baked and cured in an atmosphere having an oxygen concentration of 0.1% by volume or more and 21% by volume or less to form an adhesion film.

[0196] By baking the composition for forming an adhesion film of the present invention in such an oxygen atmosphere, a sufficiently cured film can be obtained. The atmosphere during baking may be air, but it is preferable to enclose an inert gas such as N2, Ar, or He to reduce oxygen in order to prevent oxidation of the adhesion film. In order to prevent oxidation, it is necessary to control the oxygen concentration, preferably 1000 ppm or less, more preferably 100 ppm or less (volume basis). Preventing oxidation of the adhesion film during baking is preferable because it does not increase absorption or reduce etching resistance.

[0197] Alternatively, using the above-described composition for forming an adhesion film, for example, a resist intermediate film can be formed as an intermediate film of a multilayer resist film used in lithography.

[0198] <Pattern Forming Method> In the present invention, as a pattern formation method by a four-layer resist process using the composition for forming an adhesion film of the present invention, a method for forming a pattern on a substrate to be processed, (I-1) A step of forming a resist lower layer film on the substrate to be processed, (I-2) A step of forming a silicon-containing resist intermediate film on the resist lower layer film, (I-3) A step of forming an adhesion film by applying the composition for forming an adhesion film of the present invention on the silicon-containing resist intermediate film and then performing heat treatment, (I-4) A step of forming a resist upper layer film using a photoresist material on the adhesion film, (I-5) A step of forming a pattern on the resist upper layer film by performing pattern exposure on the resist upper layer film and then developing with a developer, (I-6) A step of transferring the pattern to the adhesion film by dry etching using the resist upper layer film having the pattern as a mask, (I-7) A step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the adhesion film having the pattern as a mask, (I-8) A step of transferring the pattern to the resist lower layer film by dry etching using the silicon-containing resist intermediate film to which the pattern has been transferred as a mask, and (I-9) A step of transferring the pattern to the substrate to be processed by dry etching using the resist lower layer film to which the pattern has been transferred as a mask, A pattern formation method having the above steps is provided.

[0199] In the present invention, as a pattern formation method by a four-layer resist process using the composition for forming an adhesion film of the present invention, a method for forming a pattern on a substrate to be processed, (II-1) A step of forming a resist lower layer film on the substrate to be processed, (II-2) A step of forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist lower layer film, (II-3) A step of forming an adhesion film by applying the composition for forming an adhesion film of the present invention on the inorganic hard mask intermediate film and then performing heat treatment. (II-4) A step of forming an upper resist film using a photoresist material on the adhesion film. (II-5) After pattern-exposing the upper resist film, developing it with a developer to form a pattern in the upper resist film. (II-6) A step of transferring the pattern to the adhesion film by dry etching using the upper resist film with the pattern formed as a mask. (II-7) A step of transferring the pattern to the inorganic hard mask intermediate film by dry etching using the adhesion film with the pattern formed as a mask. (II-8) A step of transferring the pattern to the lower resist film by dry etching using the inorganic hard mask intermediate film with the pattern transferred as a mask, and (II-9) A step of transferring the pattern to the substrate to be processed by dry etching using the lower resist film with the pattern transferred as a mask. To provide a patterning method having the above steps.

[0200] Here, an example of a pattern formation method by the four-layer resist method of the present invention is shown in FIGS. 1(A) to 1(F). In the case of the four-layer resist method, as shown in FIG. 1(A), after forming the organic resist lower layer film 3 on the processed layer 2 formed on the processed substrate 1 using the organic resist lower layer film composition, a silicon-containing resist intermediate film 4 is formed, and thereon, an adhesion film 5 is formed using the composition for forming an adhesion film of the present invention, and further, a resist upper layer film 6 is formed thereon. Next, as shown in FIG. 1(B), the exposed portion 7 of the resist upper layer film 6 is exposed and PEB (post-exposure bake) is performed. Next, as shown in FIG. 1(C), development is carried out to form a resist upper layer film pattern 6a. Next, as shown in FIG. 1(D), using the fluorocarbon gas, the adhesion film 5 and the silicon-containing resist intermediate film 4 are dry-etched using the resist upper layer film pattern 6a as a mask to form an adhesion film pattern 5a and a silicon-containing resist intermediate film pattern 4a. Next, as shown in FIG. 1(E), after removing the resist upper layer film pattern 6a and the adhesion film pattern 5a, the organic resist lower layer film 3 is etched with oxygen plasma using the silicon-containing resist intermediate film pattern 4a as a mask to form an organic resist lower layer film pattern 3a. Further, as shown in FIG. 1(F), after removing the silicon-containing resist intermediate film pattern 4a, the processed layer 2 is etched using the organic resist lower layer film pattern 3a as a mask to form a pattern 2a.

[0201] When forming an inorganic hard mask intermediate film, the silicon-containing resist intermediate film 4 may be changed to an inorganic hard mask intermediate film.

[0202] In the above four-layer resist process, since the upper resist film exhibits etching resistance to fluorine-based gas or chlorine-based gas, in the above four-layer resist process, dry etching of the adhesion film using the upper resist film as a mask is preferably performed using an etching gas mainly composed of fluorine-based gas or chlorine-based gas. Dry etching of the silicon-containing resist intermediate film or inorganic hard mask intermediate film using the upper resist film and the adhesion film as masks is preferably performed using an etching gas mainly composed of fluorine-based gas. Since the silicon-containing resist intermediate film and the inorganic hard mask intermediate film exhibit etching resistance to oxygen-based gas, dry etching of the organic resist lower layer film using the silicon-containing resist intermediate film or the inorganic hard mask intermediate film as a mask is preferably performed using an etching gas mainly composed of oxygen-based gas. Since the organic resist lower layer film exhibits etching resistance to fluorine-based gas, dry etching of the substrate to be processed using the organic resist lower layer film as a mask is preferably performed using an etching gas mainly composed of fluorine-based gas.

[0203] In order to shorten the process time of dry etching, the adhesion film of the present invention is preferably a thin film. The thickness of the adhesion film is preferably 20 nm or less, more preferably 15 nm or less, still more preferably 10 nm or less, and particularly preferably 5 nm or less.

[0204] In the above pattern forming method, the upper resist film can be either positive or negative, and the same photoresist composition commonly used can be used. When forming the upper resist film with the above photoresist composition, the spin coating method is preferred.

[0205] When forming the upper resist film using the photoresist composition by the spin coating method, pre-baking is performed after resist coating, and the range of 60 to 180 °C for 10 to 300 seconds is preferred. Thereafter, exposure is performed according to a conventional method, post-exposure bake (PEB), and development are performed to obtain a resist pattern. The thickness of the upper resist film is not particularly limited, but 10 to 500 nm, particularly 20 to 400 nm is preferred.

[0206] As the exposure light, high-energy rays with a wavelength of 300 nm or less can be mentioned, specifically, far ultraviolet rays, KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), F2 laser light (157 nm), Kr2 laser light (146 nm), Ar2 laser light (126 nm), soft X-rays (EUV) of 3 to 20 nm, electron beam (EB), ion beam, X-rays, and the like.

[0207] It is preferable to perform the pattern exposure using EUV light in the step (I-5) or the step (II-5).

[0208] As the method for forming the pattern on the resist upper layer film, it is preferable to form a pattern by photolithography with a wavelength of 5 nm or more and 300 nm or less, direct drawing by an electron beam, nanoimprinting, or a combination thereof.

[0209] In addition, it is preferable that the developing method in the pattern forming method is development with an alkali or development with an organic solvent.

[0210] As the silicon-containing resist intermediate film in the four-layer resist process described above, for example, a polysiloxane-based intermediate film is preferably used. By providing an antireflection effect to the silicon-containing resist intermediate film, reflection can be suppressed. Particularly for 193 nm exposure, when a material having a high etching selectivity with the substrate and containing many aromatic groups as an organic film is used, the k value becomes high and the substrate reflection becomes high. However, by providing absorption such that an appropriate k value is obtained 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, anthracene is used for 248 nm and 157 nm exposure, and a polysiloxane having a phenyl group or an absorptive group having a silicon-silicon bond pendant and crosslinked by an acid or heat is preferably used for 193 nm exposure.

[0211] When forming an inorganic hard mask intermediate film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, or the like. For example, as a method for forming a silicon nitride film, it is described in Japanese Patent Application Laid-Open No. 2002-334869 and International Publication No. 2004 / 066377. The film thickness of the inorganic hard mask is preferably 5 to 200 nm, more preferably 10 to 100 nm. Further, as the inorganic hard mask, a SiON film having a high effect as an antireflection film is most preferably used. Since the substrate temperature when forming the SiON film is 300 to 500°C, the resist underlayer film needs to withstand a temperature of 300 to 500°C. The resist underlayer film used in the present invention has high heat resistance and can withstand a high temperature of 300°C to 500°C. Therefore, a combination of an inorganic hard mask intermediate film formed by a CVD method or an ALD method and a resist underlayer film formed by a spin coating method is possible.

[0212] Examples of the organic resist underlayer film materials that can be used for the above resist underlayer film include those that are already known as the underlayer films for the three-layer resist method or the two-layer resist method using a silicon resist composition. For example, the resins and compositions disclosed in JP-A-2012-1687, JP-A-2012-77295, JP-A-2004-264710, JP-A-2005-043471, JP-A-2005-250434, JP-A-2007-293294, JP-A-2008-65303, JP-A-2004-205685, JP-A-2007-171895, JP-A-2009-14816, JP-A-2007-199653, JP-A-2008-274250, JP-A-2010-122656, JP-A-2012-214720, JP-A-2014-29435, International Publication WO2012 / 077640, International Publication WO2010 / 147155, International Publication WO2012 / 176767, JP-A-2005-128509, JP-A-2006-259249, JP-A-2006-259482, JP-A-2006-293298, JP-A-2007-316282, JP-A-2012-145897, JP-A-2017-119671, JP-A-2019-44022, etc. can be exemplified.

[0213] For example, the above resist underlayer film can be formed on a substrate to be processed by a spin coating method or the like using a composition solution containing the above organic resist underlayer film material, similar to a photoresist composition. After forming the organic resist underlayer film 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 100 to 600 °C, and the baking time is preferably in the range of 10 to 300 seconds.

[0214] Instead of the above organic resist underlayer film material, it is also possible to apply an organic hard mask formed by CVD method or ALD method.

[0215] Note that the workpiece (workpiece substrate) is not particularly limited, and substrates such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, Al, etc., or those with a processed layer formed on the substrate are used. As the processed layer, various Low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si, etc., and their stopper films are used, and can usually be formed with a thickness of 50 to 10,000 nm, particularly 100 to 5,000 nm. When forming the processed layer, the substrate and the processed layer are made of different materials.

Example

[0216] Hereinafter, synthesis examples, comparative synthesis examples, examples, and comparative examples are shown to more specifically explain the present invention, but the present invention is not limited thereto.

[0217] [Synthesis of (A) organic polymer] (A) As the high molecular compounds of the organic polymer, (A-1) to (A-15) and comparative high molecular compounds (R-1) to (R-2) were synthesized. The following monomers (J1) to (J14) were used for the preparation of these high molecular compounds.

[0218]

Chemical formula

[0219] [Synthesis Example 1] Synthesis of high molecular compound (A-1) 100 g of monomer 1 (raw material J1) and 290.0 g of propylene glycol monomethyl ether acetate (hereinafter referred to as "PGMEA") were weighed into a 500 ml flask, and degassing was carried out while stirring to prepare a monomer solution. 2.9 g of dimethyl 2,2-azobis(2-methylpropionate) (V-601 manufactured by Wako Pure Chemical Industries, Ltd.) and 50.0 g of PGMEA were weighed into another 500 ml flask, and degassing was carried out while stirring to prepare an initiator solution. Further, 60 g of PGMEA was weighed into a 1 L flask under a nitrogen atmosphere, degassing was carried out while stirring, and then it was heated until the internal temperature reached 80°C. The monomer solution and the initiator solution were added simultaneously and separately over 4 hours. After heating and stirring for 16 hours, it was cooled to room temperature. The obtained polymerization solution was dropped into 1,500 g of stirred hexane, and the precipitated polymer was separated by filtration. Furthermore, the obtained polymer was washed twice with 600 g of hexane and then vacuum dried at 50°C for 20 hours to obtain a white powdery polymer (A-1). As a result of GPC analysis, the weight average molecular weight (Mw) of the high molecular compound (A-1) was 10,000, and the dispersity (Mw / Mn) was 2.0.

[0220] [Synthesis of Compounds (A-2) to (A-15)] Compounds (A-2) to (A-15) and (R-1) to (R-2) shown in Table 1 were obtained under the same reaction conditions as in Synthesis Example 1, except that monomer 1, monomer 2, and monomer 3 were used in the charged amounts shown in Table 1.

[0221] [Table 1]

[0222] [(B) Metal Sources (M-1) to (M-17)] The following metal compounds were used as the metal source (metal salt). (M-1): Titanium(IV) 2-ethylhexanoate (M-2): Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)chromium(III) (M-3): Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)manganese(III) (M-4): Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)iron(III) (M-5): Cobalt(II) 2-ethylhexanoate (M-6): Bis(hexafluoroacetylacetonato)nickel(II) (M-7): Copper(I) 2-ethylhexanoate (M-8): Zinc(II) 4-vinylbenzoate (M-9): Tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)zirconium(IV) (M-10): Molybdenum(IV) 2-ethylhexanoate (M-11): Indium(III) ethylbutyrate (M-12): Tin(II) acetate (M-13): Tin(II) 2-ethylhexanoate (M-14): Tin(II) acetylacetonate (M-15): Tin(II) 4-fluorobenzoate (M-16): Hafnium(IV) carboxyethyl acrylate (M-17): Bismuth(III) 2-ethylhexanoate

[0223] Preparation of the composition for forming the contact film (UDL-1 to 31, Comparative Example UDL-1 to 4) For the preparation of the adhesion film-forming composition, the above polymer compounds (A-1) to (A-15), (R-1) to (R-2), metal sources (M-1) to (M-17), thermal acid generators (AG1) to (AG3), photoacid generators (AG4) to (AG5), crosslinking agents (XL1) to (XL2), and high-boiling solvent (C1: ethylene glycol dibenzyl ether: boiling point 364°C) were used. After dissolving them in an organic solvent containing 0.001% by mass of PF636 (manufactured by OMNOVA) at the ratios shown in Tables 2-1 to 2-2, the adhesion film-forming compositions (UDL-1 to 31, Comparative Example UDL-1 to 4) were each prepared by filtering through a 0.1-μm fluororesin filter.

[0224]

Chemical formula

[0225]

Table 2-1

[0226]

Table 2-2

[0227] [Examples 1-1 to 1-31, Comparative Examples 1-1 to 1-4: Solvent Resistance Evaluation] The composition for forming an adhesion film (UDL-1 to 31, Comparative Example UDL-1 to 4) prepared above was applied onto a silicon substrate, baked at 250 °C for 60 seconds, and then the film thickness from the center part to the outer peripheral part of the substrate was measured to calculate the average film thickness (a [nm]). Subsequently, PGMEA solvent was dispensed thereon, left standing for 30 seconds, spin-dried, baked at 100 °C for 60 seconds to evaporate PGMEA, and the film thickness (b [nm]) was measured. The film thickness difference before and after PGMEA treatment (remaining film ratio: (b / a) × 100) was determined.

[0228]

Table 3

[0229] As shown in Table 3, it can be seen that all of the compositions for forming an adhesion film (UDL-1 to 31) of the present invention have good film-forming properties, and there is almost no film reduction due to solvent treatment, and a film with good solvent resistance is obtained. Further, it can be seen that the solvent resistance becomes even better by using an acid generator.

[0230] [Examples 2-1 to 2-31, Comparative Examples 2-1 to 2-4: Patterning Test (Sensitivity Evaluation)] On a silicon wafer coated with 100 nm of SiO2, as an organic underlayer film, a SOC film (ODL-306 carbon content 61 atomic%) manufactured by Shin-Etsu Chemical Co., Ltd. was used, spin-coated, and baked at 350 °C for 60 seconds to produce a carbon film with a thickness of 40 nm. Next, on the organic resist underlayer film, an SOG film (SHB-A940 Si content 25 atomic%) manufactured by Shin-Etsu Chemical Co., Ltd. was used, spin-coated, and baked at 220 °C for 60 seconds to produce a carbon film with a thickness of 20 nm. The above adhesion film-forming composition (UDL-1 to 31 and Comparative Example UDL-1 to 4) was applied and heated at 220 °C for 60 seconds using a hot plate to form an adhesion film with a thickness of 10 nm.

[0231] Subsequently, the resist materials shown in Table 4 were spin-coated on the above adhesion film and pre-baked at 105 °C for 60 seconds using a hot plate to produce a resist film with a thickness of 35 nm. This was exposed using an EUV scanner NXE3300 (NA0.33, σ0.9 / 0.6, quadrupole illumination, L / S pattern with a wafer size pitch of 44 nm) manufactured by ASML, PEB was performed on a hot plate at 100 °C for 60 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds to obtain a pattern with a line dimension of 22 nm.

[0232] The line dimension was measured using a length measurement SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, and pattern collapse was observed. When no pattern collapse was seen, it was evaluated as good, and when pattern collapse was seen, it was evaluated as bad. Also, the cross-sectional shape was observed with an electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation. When no trailing shape was seen, it was evaluated as good, and when an obvious trailing shape was seen, it was evaluated as bad.

[0233] In addition, when the line dimension was made thinner by increasing the exposure dose, the minimum dimension at which the line resolved without collapsing was determined and defined as the collapse limit (nm). The smaller the numerical value, the higher the collapse resistance and the more preferable.

[0234] Also, the exposure dose that can obtain a line dimension of 22 nm was evaluated as the sensitivity, and it was determined that the smaller the exposure dose, the more it contributed to the high sensitivity of the resist upper layer film.

[0235] The results are shown in Table 5.

[0236]

Chemical formula

[0237]

Chemical formula

[0238] Surfactant: FC-4430 manufactured by 3M

[0239]

Table 4

[0240]

Table 5

[0241] As shown in Table 5, in Examples 2-1 to 2-31 using the composition for forming an adhesion film of the present invention, in the formation of a line width 22 nm pattern using EUV exposure, a vertical pattern cross-section could be obtained, and it was confirmed that there was no pattern collapse. On the other hand, in Comparative Example 2-4 using Comparative Example UDL-4 that does not contain an organic polymer, collapse of the resist pattern was observed. Also, in Comparative Examples 2-2 and 2-3 using Comparative Examples UDL-2 and 3 containing a polymer compound that does not contain any of the repeating units represented by the following formulas (1) and (2), it was found that the effect of suppressing the collapse of the fine line pattern was small compared to Examples 2-1 to 2-31.

[0242] Furthermore, when the composition for forming an adhesion film of the present invention is used as an adhesion film, it is found that a resist pattern can be formed with high sensitivity (Examples UDL-1 to 31). In Examples 2-16 to 2-31 in which the organic polymer of the composition for forming an adhesion film was fixed to A3 and various (B) metal sources were added, Examples 2-27 to 2-30 using a composition for forming an adhesion film containing Sn as the (B) metal source showed particularly excellent sensitivity. On the other hand, in Comparative Example 2-1 where no (B) metal source was added, the result was inferior in sensitivity.

[0243] As described above, since the present invention has excellent adhesion to the upper resist, it has a high effect of suppressing the collapse of fine line patterns, and can further form an adhesion film that can contribute to the improvement of the sensitivity of the upper resist. Therefore, it has high utility value in the field of EUV lithography.

[0244] This specification includes the following inventions.

[0245] [1]: A composition for forming an adhesion film formed between a silicon-containing intermediate film and a resist upper layer film, the composition comprising (A) an organic polymer, (B) a metal source, and (C) an organic solvent, and the (A) organic polymer being a high molecular compound containing one or both of the repeating units represented by the following formulas (1) and (2), and the (B) metal source being a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal and β-diketones. A composition for forming an adhesion film, characterized in that.

Chemical formula

[0246] [2]: The composition for forming an adhesion film according to [1] above, wherein the heterocyclic structure of R2 in the formulas (1) and (2) is a heterocyclic structure containing an oxygen atom.

[0247] [3]: The composition for forming an adhesion film according to [1] or [2] above, wherein R2 in the formulas (1) and (2) is a monovalent organic group containing a group selected from the following formulas (R2-1) to (R2-3).

Chemical formula

[0248] [4]: The composition for forming an adhesion film according to any one of [1] to [3] above, wherein the (A) organic polymer is a high molecular compound containing any one of the repeating units represented by the following formula (3a) or formula (3b).

Chemical formula

[0249] [5]: The composition for forming an adhesion film according to any one of [1] to [4] above, wherein the (A) organic polymer is a high molecular compound having a weight average molecular weight of 6,000 to 50,000.

[0250] [6]: The composition for forming an adhesion film according to any one of [1] to [5] above, wherein the (A) organic polymer is a high molecular compound having a dispersity represented by weight average molecular weight / number average molecular weight of 3.0 or less.

[0251] [7]: The composition for forming an adhesion film according to any one of [1] to [6] above, wherein the (B) metal source is a salt of the metal and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms.

[0252] [8]: The composition for forming an adhesion film according to any one of [1] to [7] above, wherein the (B) metal source has a structure represented by the following formula (B-1). [Chemical formula] (In the formula, M is selected from any one of Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi; R1 is a monovalent organic group having 1 to 30 carbon atoms; and n is an integer of 1 to 4.)

[0253] [9]: The composition for forming an adhesion film according to [8] above, wherein R1 in the formula (B-1) is a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms.

[0254]

[10] : The composition for forming an adhesion film according to [8] or [9] above, wherein R1 in the formula (B-1) is a branched alkyl group having 3 to 10 carbon atoms.

[0255]

[11] : The composition for forming an adhesion film according to any one of [1] to

[10] above, wherein the metal of the (B) metal source is Sn.

[0256]

[12] : The composition for forming an adhesion film according to any one of [1] to

[11] above, further containing at least one or more of (D) a thermal acid generator, (E) a photoacid generator, (F) a crosslinking agent, and (G) a surfactant.

[0257]

[13] : The composition for forming an adhesion film according to any one of [1] to

[12] above, wherein the (C) organic solvent is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher ((C-1) high-boiling solvent).

[0258]

[14] : A method for forming a pattern on a substrate to be processed, comprising: (I-1) a step of forming a resist underlayer film on the substrate to be processed; (I-2) a step of forming a silicon-containing resist intermediate film on the resist underlayer film; (I-3) a step of forming an adhesion film by applying the composition for forming an adhesion film according to any one of [1] to

[13] above on the silicon-containing resist intermediate film and then performing heat treatment; (I-4) a step of forming a resist upper layer film using a photoresist material on the adhesion film; (I-5) a step of forming a pattern in the resist upper layer film by subjecting the resist upper layer film to pattern exposure and then developing it with a developer; (I-6) a step of transferring the pattern to the adhesion film by dry etching using the resist upper layer film having the pattern formed thereon as a mask; (I-7) a step of transferring the pattern to the silicon-containing resist intermediate film by dry etching using the adhesion film having the pattern formed thereon as a mask; (I-8) a step of transferring the pattern to the resist underlayer film by dry etching using the silicon-containing resist intermediate film having the pattern transferred thereto as a mask; and (I-9) a step of transferring the pattern to the substrate to be processed by dry etching using the resist underlayer film having the pattern transferred thereto as a mask. A pattern forming method characterized by comprising these steps.

[0259]

[15] : A method for forming a pattern on a substrate to be processed, comprising: (II-1) forming a resist underlayer film on the substrate to be processed; (II-2) forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film; (II-3) applying the composition for forming an adhesion film according to any one of [1] to

[13] above on the inorganic hard mask intermediate film and then performing heat treatment to form an adhesion film; (II-4) forming a resist upper layer film using a photoresist material on the adhesion film; (II-5) performing pattern exposure on the resist upper layer film and then developing with a developer to form a pattern on the resist upper layer film; (II-6) using the resist upper layer film on which the pattern is formed as a mask and transferring the pattern to the adhesion film by dry etching; (II-7) using the adhesion film on which the pattern is formed as a mask and transferring the pattern to the inorganic hard mask intermediate film by dry etching; (II-8) using the inorganic hard mask intermediate film on which the pattern is transferred as a mask and transferring the pattern to the resist underlayer film by dry etching; and (II-9) using the resist underlayer film on which the pattern is transferred as a mask and transferring the pattern to the substrate to be processed by dry etching. A pattern forming method characterized by comprising the above steps.

[0260]

[16] : The pattern forming method according to

[14] above, characterized in that in the step (I-5), the pattern exposure is performed using EUV light.

[0261]

[17] : The pattern forming method according to

[15] above, characterized in that in the step (II-5), the pattern exposure is performed using EUV light.

[0262] Note that the present invention is not limited to the above embodiments. The above embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Explanation of Reference Numerals

[0263] 1…Substrate to be processed, 2…Layer to be processed, 2a…Pattern (pattern formed on the layer to be processed), 3…Lower organic resist film, 3a…Lower organic resist film pattern, 4…Silicon-containing resist intermediate film, 4a…Silicon-containing resist intermediate film pattern, 5…Adhesion film, 5a…Adhesion film pattern, 6…Upper resist film, 6a…Upper resist film pattern, 7…Exposed part.

Claims

1. An adhesion film forming composition for forming an adhesion film formed between a silicon-containing intermediate film and a resist upper layer film, wherein the composition contains (A) an organic polymer, (B) a metal source, and (C) an organic solvent, and the (A) organic polymer is a high molecular compound containing one or both of the repeating units represented by the following formula (1) and formula (2), the (B) metal source is a salt of a metal selected from Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms, or a complex of the metal and β-diketones, and is characterized by an adhesion film forming composition. 【Chemical Formula 1】 (wherein, R １ is a hydrogen atom or a methyl group, and R ２ is a monovalent organic group having 2 to 20 carbon atoms containing a heterocyclic structure, and R ３ is a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms.)

2. R in the formulas (1) and (2) above ２ The composition for forming an adherent film according to claim 1, wherein the heterocyclic structure of ２ is a heterocyclic structure containing an oxygen atom.

3. R in the formulas (1) and (2) above ２ is a monovalent organic group containing a group selected from the following formulas (R ２ -1) to (R ２ -3), and the composition for forming an adhesion film according to claim 1, characterized in that. 【Chemical 2】 (wherein R ４ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the broken line indicates a bond.)

4. The adhesion film forming composition according to claim 1, wherein the (A) organic polymer is a high molecular compound further containing any one of the repeating units represented by the following formula (3a) or formula (3b). [Chemical Formula 3] (wherein R Ｆ１ is a monovalent organic group having 1 to 20 carbon atoms containing at least one F atom, and R Ｆ２ is an F atom or a monovalent organic group having 1 to 10 carbon atoms containing one or more F atoms, and R １ is the same as the above formula (1), and n represents 1 to 5.)

5. The adhesion film forming composition according to claim 1, wherein the (A) organic polymer is a high molecular compound having a weight average molecular weight of 6,000 to 50,000.

6. The adhesion film forming composition according to claim 1, wherein the (A) organic polymer is a high molecular compound having a dispersity represented by weight average molecular weight / number average molecular weight of 3.0 or less.

7. The adhesion film forming composition according to claim 1, wherein the (B) metal source is a salt of the metal and a monovalent to tetravalent carboxylic acid having 1 to 30 carbon atoms.

8. The adhesion film forming composition according to claim 1, wherein the (B) metal source has a structure represented by the following formula (B-1). 【Chemical 4】 (In the formula, M is selected from any of Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Hf, and Bi, and R １ is a monovalent organic group having 1 to 30 carbon atoms, and n is an integer of 1 to 4.)

9. R in the formula (B-1) １ The composition for forming an adhesion film according to claim 8, wherein R is a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms.

10. R in the formula (B-1) １ The composition for forming an adhesion film according to claim 8, wherein R is a branched alkyl group having 3 to 10 carbon atoms.

11. The adhesion film forming composition according to claim 1, wherein the metal of the (B) metal source is Sn.

12. Furthermore, it contains at least one or more of (D) a thermal acid generator, (E) a photoacid generator, (F) a crosslinking agent, and (G) a surfactant, and is characterized by the adhesion film forming composition according to claim 1.

13. The adhesion film forming composition according to claim 1, wherein the (C) organic solvent is a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher ((C-1) high boiling point solvent).

14. A method for forming a pattern on a substrate to be processed, (I-1) A step of forming a resist lower layer film on the substrate to be processed, Step (I-2): Forming a silicon-containing resist intermediate film on the resist underlayer film; Step (I-3): Applying the composition for forming an adhesion film according to any one of claims 1 to 13 on the silicon-containing resist intermediate film and then performing heat treatment to form an adhesion film; Step (I-4): Forming a resist upper layer film using a photoresist material on the adhesion film; Step (I-5): After pattern-exposing the resist upper layer film, developing it with a developer to form a pattern in the resist upper layer film; Step (I-6): Using the resist upper layer film on which the pattern is formed as a mask and transferring the pattern to the adhesion film by dry etching; Step (I-7): Using the adhesion film on which the pattern is formed as a mask and transferring the pattern to the silicon-containing resist intermediate film by dry etching; Step (I-8): Using the silicon-containing resist intermediate film onto which the pattern is transferred as a mask and transferring the pattern to the resist underlayer film by dry etching; and Step (I-9): Using the resist underlayer film onto which the pattern is transferred as a mask and transferring the pattern to the substrate to be processed by dry etching; A pattern forming method, characterized by comprising the above steps.

15. A method for forming a pattern on a substrate to be processed, comprising: Step (II-1): Forming a resist underlayer film on the substrate to be processed; Step (II-2): Forming an inorganic hard mask intermediate film selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film on the resist underlayer film; Step (II-3): Applying the composition for forming an adhesion film according to any one of claims 1 to 13 on the inorganic hard mask intermediate film and then performing heat treatment to form an adhesion film; Step (II-4): Forming a resist upper layer film using a photoresist material on the adhesion film; Step (II-5): After pattern-exposing the resist upper layer film, developing it with a developer to form a pattern in the resist upper layer film; Step (II-6): Using the resist upper layer film on which the pattern is formed as a mask and transferring the pattern to the adhesion film by dry etching; Step (II-7): Using the adhesion film on which the pattern is formed as a mask and transferring the pattern to the inorganic hard mask intermediate film by dry etching; Step (II-8): Using the inorganic hard mask intermediate film onto which the pattern is transferred as a mask and transferring the pattern to the resist underlayer film by dry etching; and Step (II-9): Transferring the pattern to the substrate to be processed by dry etching using the resist underlayer film onto which the pattern has been transferred as a mask. A pattern forming method, characterized by comprising the above steps. **Claim 16** The pattern forming method according to claim 14, wherein in the step (I-5), the pattern exposure is performed using EUV light. **Claim 17** The pattern forming method according to claim 15, wherein in the step (II-5), the pattern exposure is performed using EUV light.

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