Pattern forming method

Abstract

The invention relates to a pattern forming method. The invention provides a pattern forming method capable of forming a fine pattern with a non-rough edge. A pattern forming method includes the steps of: sequentially laminating an organic underlayer film, a silicon-containing hard mask, a silicon-containing antireflection film, and a photoresist film on a substrate to be processed, forming a resist pattern on the photoresist film, forming a hard mask intermediate film pattern, forming an organic underlayer film pattern, and forming a pattern on the substrate to be processed; the silicon-containing anti-reflective film is formed using a composition for forming a silicon-containing anti-reflective film, which contains a crosslinking agent and a polysiloxane that contains at least one of a repeating unit represented by general formula (Sx-1), a repeating unit represented by general formula (Sx-2), and a partial structure represented by general formula (Sx-3). # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a patterning method using a silicon-containing antireflection film. Background Art

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

[0003] However, when miniaturization is carried out while maintaining the film thickness of the photoresist film used, that is, when the pattern width is reduced to a smaller size, the resolution performance of the photoresist film decreases. Also, when attempting to develop the pattern of the photoresist film using a developer, the aspect ratio becomes too large, resulting in a problem of pattern collapse. Therefore, along with the miniaturization of the pattern, the photoresist film has gradually become thinner.

[0004] On the other hand, for the processing of the substrate to be processed, the following method is usually used: using the patterned photoresist film as an etching mask and performing dry etching on the substrate; however, in reality, there is no dry etching method that can achieve complete etching selectivity between the photoresist film and the substrate to be processed. Therefore, in the processing of the substrate, the photoresist film is also damaged and collapses, and the resist pattern cannot be correctly transferred to the substrate to be processed. Thus, along with the miniaturization of the pattern, the resist composition has also gradually sought higher dry etching resistance. However, on the other hand, in order to improve the resolution, the resin used in the photoresist composition has gradually sought a resin with low light absorption at the exposure wavelength. Therefore, as the exposure light wavelength has become shorter to i-ray, KrF, ArF, the resin has gradually changed to novolak resin, polyhydroxystyrene, and a resin having an aliphatic polycyclic skeleton. However, in reality, the etching rate in the dry etching conditions during substrate processing has gradually become faster, and the latest photoresist compositions with high resolution tend to have weaker etching resistance.

[0005] Considering this situation, it has become necessary to perform dry etching on the substrate to be processed using a thinner photoresist film with weaker etching resistance, and ensuring the materials and processes in this processing step have gradually become an urgent matter.

[0006] The multi-layer resist method is one of the methods to solve such problems. In this method, a lower layer film having a different etching selectivity from the photoresist film (i.e., the upper resist film) is interposed between the upper resist film and the substrate to be processed. After a pattern is obtained on the upper resist film, the pattern on the upper resist film is used as a dry etching mask, and the pattern is transferred to the lower layer film by dry etching. Then, using the lower layer film as a dry etching mask, the pattern is transferred to the substrate to be processed by dry etching.

[0007] Among the multi-layer resist methods, there is a three-layer resist method that can be implemented using a general resist composition used in the single-layer resist method. For example, in this three-layer resist method, an organic film derived from a novolak resin or the like is formed on the substrate to be processed as the lower resist film, a silicon-containing resist intermediate film is formed thereon as the resist intermediate film, and then a normal organic photoresist film is formed thereon as the upper resist film. When performing dry etching using a fluorine-based gas plasma, since the organic upper resist film can obtain a better etching selectivity ratio compared to the silicon-containing resist intermediate film, the pattern of the upper resist film can be transferred to the silicon-containing resist intermediate film by dry etching using the fluorine-based gas plasma. According to this method, even when using a resist composition that is difficult to form a pattern with a sufficient film thickness for directly processing the substrate to be processed, or a resist composition that does not have sufficient dry etching resistance for processing the substrate, the pattern of the upper resist film can still be transferred to the silicon-containing resist intermediate film (resist intermediate film). Then, by performing dry etching using an oxygen-based or hydrogen-based gas plasma for the transfer of the organic film pattern, an organic film (lower resist film) derived from a novolak resin or the like that has sufficient dry etching resistance for processing the substrate can be obtained. As described above, the lower resist film, such as those described in Patent Document 1, etc., are well-known.

[0008] As the silicon-containing resist intermediate film used in the three-layer resist method as described above, a silicon-containing inorganic film obtained by CVD is used, such as a SiO 2 film (e.g., Patent Document 2, etc.), a SiON film (e.g., Patent Document 3, etc.), etc., a silicon-containing hard mask, a SOG (spin-on glass) film (e.g., Patent Document 4, and Non-Patent Document 1, etc.) obtained as a film by spin coating, a crosslinkable silsesquioxane film (e.g., Japanese Patent Document 5, etc.), etc., and a polysilane film (e.g., Patent Document 6, etc.) can also be used. In an advanced three-layer resist method, a SOG film is often used to easily adjust the antireflection effect.

[0009] There are some problems with the SOG film used in the three-layer resist method. For example, when optical lithography is used to form a resist pattern, it is known that the exposure light will be reflected on the substrate and interfere with the incident light, causing the so-called standing wave problem. In order to obtain a fine pattern with smooth edges of the resist film under the most advanced ArF immersion / high NA exposure conditions, the intermediate film must have an anti-reflection effect. In addition, in the most advanced semiconductor processing as mentioned above, because the photoresist is thinner, the intermediate film is also required to be thinner. In the next generation of exposure processing, it is required to give the intermediate film an anti-reflection effect with a film thickness of less than 30nm. In addition, in order to improve the etching selectivity ratio between the SOG film and the lower film, the smaller the dry etching speed of the oxygen plasma generally used in the processing of the resist lower film, the better. Considering the trend of thin film, the dry etching resistance of the SOG film is sought to be improved.

[0010] In the three-layer resist method, it is difficult to develop a SOG film that has both antireflection effect and dry etching resistance in a high dimension. In order to improve the antireflection effect, it is necessary to use polysiloxane with an organic group with a high refractive index, but if the introduction rate of the organic group is increased, the silicon component in the film decreases, and the dry etching resistance to oxygen deteriorates. On the other hand, there is a four-layer resist method with two films that have different effects on antireflection and dry etching resistance. Patent document 7 reports a four-layer resist method consisting of an organic lower layer film, a silicon-containing hard mask, an organic antireflection film, and a photoresist.

[0011] Anti-reflective film needs to have functions as a layer to prevent the interaction between the processed substrate and the photoresist, a layer to prevent the material used in the photoresist or the substance generated when the photoresist is exposed from causing adverse effects on the substrate, a layer to prevent the substance generated from the substrate from diffusing to the upper photoresist during heating and firing, and a barrier layer to reduce the poisoning of the photoresist layer caused by the dielectric layer of the semiconductor substrate, etc. However, organic anti-reflective film is not ideal in terms of these functions and is considered to need further improvement.

[0012] Patent document 8 reports a four-layer resist method using a silicon-containing antireflection film. It reports that it is effective in suppressing the poisoning of the organic antireflection film, but it is a technology that corresponds to a pattern rule of 65nm. It is predicted that advanced semiconductor manufacturing that requires technology that corresponds to pattern rules below 15nm will need further improvement.

[0013] For example, in microfabrication using an ArF excimer laser (wavelength 193 nm) and an EUV excimer laser (wavelength 13 nm), etc., the wiring width is narrowed, and thus pattern collapse of a photoresist (also simply referred to as a resist) occurs. Also, in order to prevent pattern collapse of the resist, as the wiring width decreases, the thickness of the resist layer also decreases. When such a thin-film resist is used, the underlying resist film thereof seeks to further improve the dry etching rate. However, for an organic-based underlying resist film (organic underlayer film), film loss of the organic-based resist film may occur due to dry etching gases (e.g., fluorine-based gases, oxygen, etc.) of the organic-based underlying resist film. When a silicon-containing resist intermediate film is used under the organic-based resist film, when the silicon-containing resist intermediate film is dry-etched with a fluorine-based gas using the resist pattern as an etching mask, if it is a fluorine-based gas, the film loss of the organic-based resist film (the resist film having the resist pattern formed) is small, and the resist pattern formed by the thin-film resist can be correctly transferred to the silicon-containing resist intermediate film. Further, if the pattern of the silicon-containing resist intermediate film is used as an etching mask and the organic underlayer film is dry-etched with an oxygen-based dry etching gas, the film loss of the silicon-containing resist intermediate film is small, and the resist pattern can be correctly transferred to the organic underlayer film. By using the organic underlayer film having the resist pattern transferred thereto as an etching mask, the semiconductor substrate can be processed with a fluorine-based gas.

[0014] However, for the three-layer treatment of the organic underlayer film, the silicon-containing resist intermediate film, and the resist film on the semiconductor substrate shown above, there is a problem in that it is technically difficult to balance high refractive index and dry etching resistance of the silicon-containing resist intermediate film.

[0015] Also, due to thinning for preventing pattern collapse of the resist film, thinning is also required for the silicon-containing resist intermediate film. Thus, for the most advanced ArF immersion / high NA exposure conditions, in order to further improve the anti-reflection effect, the silicon-containing resist intermediate film needs to have a high refractive index. In order to form a silicon-containing resist intermediate film having a high refractive index, generally, a SOG material containing a polysiloxane having an organic group with a high refractive index is used. However, since the introduction rate of the organic group in these materials is high and the silicon component in the film decreases, the dry etching resistance to oxygen becomes insufficient. In order to transfer a fine pattern with a non-rough edge with high precision onto the substrate to be processed, a silicon-containing resist intermediate film having excellent dry etching resistance is required.

[0016] Furthermore, Patent Document 9 discloses some pattern formation methods. For example, it describes forming an organic film on a workpiece and forming a silicon-containing resist underlayer film on the organic film, and forming a resist upper layer film on the silicon-containing resist underlayer film. In another example, it describes forming a hard mask mainly composed of carbon on a workpiece, forming a silicon-containing resist underlayer film on the hard mask, and forming a resist upper layer film on the silicon-containing resist underlayer film. However, these processes have insufficient antireflection effects under advanced ArF immersion / high NA exposure conditions, and it is considered that a new method capable of forming fine patterns with non-rough edges is required.

[0017] Prior Art Documents

[0018] Patent Documents

[0019] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2004-205685

[0020] [Patent Document 2] Japanese Unexamined Patent Application Publication No. 7-183194

[0021] [Patent Document 3] Japanese Unexamined Patent Application Publication No. 7-181688

[0022] [Patent Document 4] Japanese Unexamined Patent Application Publication No. 5-291208

[0023] [Patent Document 5] Japanese Patent Application Laid-Open No. 2005-520354

[0024] [Patent Document 6] Japanese Unexamined Patent Application Publication No. 11-60735

[0025] [Patent Document 7] Japanese Patent No. 5057107 Specification

[0026] [Patent Document 8] Japanese Patent No. 4481902 Specification

[0027] [Patent Document 9] Japanese Unexamined Patent Application Publication No. 2022-90309

[0028] Non-Patent Documents

[0029] [Non-Patent Document 1] J.Appl.Polym.Sci., Vol.88, 636-640(2003) Summary of the Invention

[0030] [Problems to be Solved by the Invention]

[0031] The present invention has been made to solve the above problems, and an object thereof is to provide a pattern formation method capable of forming fine patterns with non-rough edges.

[0032] [Means for Solving the Problems]

[0033] In order to solve the above problems, the present invention provides a pattern forming method, which is characterized by including the following steps:

[0034] (1) On a substrate to be processed, (A) an organic underlayer film, (B) a silicon-containing hard mask, (C) a silicon-containing antireflection film, and (D) a photoresist film are sequentially laminated.

[0035] (2) The pattern circuit region of the aforementioned (D) photoresist film is exposed to form an exposed pattern, and then the aforementioned exposed pattern is developed with a developer to form a resist pattern on the aforementioned (D) photoresist film.

[0036] (3) Using the obtained resist pattern as an etching mask, the aforementioned (C) silicon-containing antireflection film and the aforementioned (B) silicon-containing hard mask are etched to form an intermediate hard mask pattern.

[0037] (4) Using the obtained intermediate hard mask pattern as an etching mask, the aforementioned (A) organic underlayer film is etched to form an organic underlayer film pattern, and

[0038] (5) Using the obtained organic underlayer film pattern as an etching mask, the aforementioned substrate to be processed is etched to form a pattern on the aforementioned substrate to be processed.

[0039] The aforementioned (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film containing a polysiloxane containing any one or more of a repeating unit represented by the following general formula (Sx-1), a repeating unit represented by the following general formula (Sx-2), and a partial structure represented by the following general formula (Sx-3), and a crosslinking agent.

[0040] [Chemical formula 1]

[0041]

[0042] In the formula, R a , R b and R c are each independently a monovalent organic group having 1 to 30 carbon atoms, which may be the same or different.

[0043] If such a pattern forming method is used, by the combination of the (B) silicon-containing hard mask and the (C) silicon-containing antireflection film, a high antireflection effect can be exhibited under ArF immersion / high NA exposure conditions, and thus a fine pattern with a non-rough edge can be obtained. Further, since the composition for forming a silicon-containing antireflection film contains a crosslinking agent, it can exhibit an excellent poisoning inhibition effect compared with a known antireflection film, and thus has good adhesion to the resist pattern and can also exhibit an effect of preventing the collapse of the fine pattern. Therefore, the pattern forming method of the present invention can transfer the resist pattern shape onto the substrate to be processed with high precision.

[0044] Further, regarding the aforementioned (B) silicon-containing hard mask, it is preferable to form a layer selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxynitride film.

[0045] By using such a (B) silicon-containing hard mask, the shape of the resist pattern can be transferred onto the substrate to be processed with higher precision. Further, by combining with the (C) silicon-containing antireflection film, an excellent antireflection effect can be achieved.

[0046] In the aforementioned general formulas (Sx-1) to (Sx-3), it is preferable to form the aforementioned (C) silicon-containing antireflection film using a polysiloxane in which at least one of R a ~R c is an organic group having one or more carbon-oxygen single bonds or carbon-oxygen double bonds.

[0047] By using such a (C) silicon-containing resist antireflection film, the adhesion to the resist pattern can be further improved, and the collapse of fine patterns can be more reliably prevented.

[0048] It is preferable to form the aforementioned (C) silicon-containing antireflection film using a compound containing an isocyanuric acid structure as the aforementioned crosslinking agent.

[0049] By using such a (C) silicon-containing antireflection film, the denseness of the silicon-containing antireflection film is improved, and the ability to suppress the poisoning that may occur when the basic components generated from the (C) silicon-containing hard mask move to the (D) photoresist film and reduce the sensitivity and resolution of the resist can be further improved. Further, the adhesion to the resist pattern can be further improved, and the collapse of fine patterns can be more reliably prevented. Moreover, the refractive index of the (C) silicon-containing antireflection film can be increased, and a more excellent antireflection effect can be imparted.

[0050] It is preferable to form the aforementioned (A) organic underlayer film by CVD method.

[0051] Thus, by forming the (A) organic underlayer film, compared with the pattern formation method using a spin-coated organic underlayer film, the shape of the resist pattern can be transferred onto the substrate to be processed with higher precision.

[0052] Regarding the aforementioned (A) organic underlayer film, it is preferable to form a film containing any one of a graphene film, an amorphous carbon film, and a diamond-like carbon film.

[0053] By using such an (A) organic underlayer film, it shows high resistance to fluorine-based gases used in dry etching of the substrate to be processed, so the shape of the resist pattern can be transferred onto the substrate to be processed with higher precision.

[0054] It is preferable to form the aforementioned (B) silicon-containing hard mask and the aforementioned (C) silicon-containing antireflection film so that the film thickness FTb of the (B) silicon-containing hard mask and the film thickness FTc of the (C) silicon-containing antireflection film satisfy the relationship of FTb>FTc.

[0055] By using the silicon-containing antireflection film having such a film thickness range, the resist pattern shape can be transferred onto the silicon-containing antireflection film at high speed, and thus a pattern shape with smaller roughness can be transferred onto the substrate to be processed.

[0056] It is preferable to form the above-mentioned silicon-containing antireflection film so that the film thickness of the silicon-containing antireflection film is 15 nm or less.

[0057] By using the silicon-containing antireflection film having such a film thickness range, the resist pattern shape can be transferred onto the silicon-containing antireflection film at high speed, and thus a pattern shape with smaller roughness can be transferred onto the substrate to be processed.

[0058] [Effects of the Invention]

[0059] As described above, in the pattern forming method of the present invention, a fine pattern with non-rough edges can be obtained in a state where poisoning is suppressed. Description of the Drawings

[0060] Figure 1 (A) to (F) are explanatory views of an example (four-layer resist process) of the pattern forming method of the present invention.

[0061] Figure 2 (G) to (L) are explanatory views of an example (three-layer resist process) of the pattern forming method for a comparative example.

[0062] Figure 3 is an explanatory view of the reflectivity calculation of the pattern forming method. Detailed Description of the Invention

[0063] As described above, there is a need to develop a pattern forming method using a multilayer resist method that has an excellent antireflection effect capable of forming a fine pattern with non-rough edges and a processing selectivity capable of transferring the resist pattern shape onto the substrate to be processed with high precision in the fine patterning process using ArF immersion / high NA exposure conditions in the semiconductor device manufacturing process.

[0064] Also, as described above, in the three-layer process of the organic underlayer film, the silicon-containing hard mask, and the resist film on the semiconductor substrate, there is a problem that it is technically difficult to balance the high refractive index of the silicon-containing hard mask and the dry etching resistance.

[0065] In the face of such problems, some people have explored whether the above problems can be solved by providing a silicon-containing antireflection film between the silicon-containing hard mask (B) and the photoresist film (D). However, the silicon-containing antireflection film disclosed in Patent Document 8 has problems in suppressing the poisoning of the underlying layer of the resist by the photoresist film, and efforts have been made to explore the silicon-containing antireflection film. As a result, it has been found that if the silicon-containing antireflection film (C) is formed from a composition containing a polysiloxane containing any one or more of the repeating units and structures represented by the above formulas (Sx-1) to (Sx-3) and a crosslinking agent, both excellent poisoning suppression effect and antireflection effect can be achieved, so that poisoning can be sufficiently suppressed and fine patterns with smooth edges can be transferred.

[0066] Moreover, the inventors of the present application have found that the above problems can be solved by a patterning method including the following steps, and thus completed the present invention: on a semiconductor substrate, layers of an organic underlayer film (A), a silicon-containing hard mask (B), the above silicon-containing antireflection film (C), and a photoresist film (D) are sequentially stacked, the photoresist film (D) is exposed and developed to form a resist pattern, and each layer is processed based on the resist pattern, and finally a resist transfer pattern is formed on the processed substrate.

[0067] That is, the present invention is a patterning method including the following steps:

[0068] (1) On a processed substrate, an organic underlayer film (A), a silicon-containing hard mask (B), a silicon-containing antireflection film (C), and a photoresist film (D) are sequentially stacked.

[0069] (2) The patterned circuit region of the aforementioned photoresist film (D) is exposed to form an exposed pattern, and then the exposed pattern is developed with a developer to form a resist pattern on the aforementioned photoresist film (D).

[0070] (3) Using the obtained resist pattern as an etching mask, the aforementioned silicon-containing antireflection film (C) and the aforementioned silicon-containing hard mask (B) are etched to form a hard mask intermediate film pattern.

[0071] (4) Using the obtained hard mask intermediate film pattern as an etching mask, the aforementioned organic underlayer film (A) is etched to form an organic underlayer film pattern, and

[0072] (5) Using the obtained organic underlayer film pattern as an etching mask, the aforementioned processed substrate is etched to form a pattern on the aforementioned processed substrate.

[0073] The aforementioned silicon-containing antireflection film (C) is formed from a composition for forming a silicon-containing antireflection film containing a polysiloxane containing any one or more of the repeating units represented by the following general formula (Sx-1), the repeating units represented by the following general formula (Sx-2), and the partial structure represented by the following general formula (Sx-3), and a crosslinking agent.

[0074] [Chemical formula 2]

[0075]

[0076] In the formula, R a 、R b and R c are monovalent organic groups having 1 to 30 carbon atoms, which may be the same or different from each other.

[0077] The present invention will be described in detail below, but the present invention is not limited thereto.

[0078] <Pattern forming method>

[0079] The present invention is a pattern forming method, which is characterized by including the following steps:

[0080] (1) On a substrate to be processed, an (A) organic underlayer film, a (B) silicon-containing hard mask, a (C) silicon-containing antireflection film, and a (D) photoresist film are sequentially laminated.

[0081] (2) The pattern circuit region of the aforementioned (D) photoresist film is exposed to form an exposed pattern, and then the exposed pattern is developed with a developer to form a resist pattern on the aforementioned (D) photoresist film.

[0082] (3) Using the obtained resist pattern as an etching mask, the aforementioned (C) silicon-containing antireflection film and the aforementioned (B) silicon-containing hard mask are etched to form a hard mask intermediate film pattern.

[0083] (4) Using the obtained hard mask intermediate film pattern as an etching mask, the aforementioned (A) organic underlayer film is etched to form an organic underlayer film pattern, and

[0084] (5) Using the obtained organic underlayer film pattern as an etching mask, the aforementioned substrate to be processed is etched to form a pattern on the aforementioned substrate to be processed.

[0085] The aforementioned (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film containing a polysiloxane containing any one or more of a repeating unit represented by the following general formula (Sx-1), a repeating unit represented by the following general formula (Sx-2), and a partial structure represented by the following general formula (Sx-3), and a crosslinking agent.

[0086] [Chemical formula 3]

[0087]

[0088] In the formula, R a 、R b and R c are monovalent organic groups having 1 to 30 carbon atoms, which may be the same or different from each other.

[0089] In the above-described pattern forming method, by combining a (C) silicon-containing antireflection film having excellent antireflection properties and a (B) silicon-containing hard mask having excellent dry etching resistance, in the fine patterning process using ArF immersion / high NA exposure conditions in the semiconductor device manufacturing process, an antireflection pattern shape with a non-rough edge can be accurately transferred onto the substrate to be processed while sufficiently suppressing poisoning.

[0090] The following describes each step of the pattern forming method of the present invention in more detail.

[0091] [(1) Lamination step]

[0092] This (1) step is a step of sequentially laminating an (A) organic underlayer film (A layer), a (B) silicon-containing hard mask (B layer), a (C) silicon-containing antireflection film (C layer), and a (D) photoresist film (D layer) on the substrate to be processed. The pattern forming method of the present invention forms at least the above four layers.

[0093] [<(A) Organic underlayer film (A layer)>]

[0094] As the organic underlayer film material that can be used for the (A) organic underlayer film (A layer), for example, those known as the underlayer films for the three-layer resist method or the two-layer resist method using a silicon resist composition. For example, resins or compositions shown in Japanese Patent Application Laid-Open No. 2012-1687, Japanese Patent Application Laid-Open No. 2012-77295, Japanese Patent Application Laid-Open No. 2004-264710, Japanese Patent Application Laid-Open No. 2005-043471, Japanese Patent Application Laid-Open No. 2005-250434, Japanese Patent Application Laid-Open No. 2007-293294, Japanese Patent Application Laid-Open No. 2008-65303, Japanese Patent Application Laid-Open No. 2004-205685, Japanese Patent Application Laid-Open No. 2007-171895, Japanese Patent Application Laid-Open No. 2009-14816, Japanese Patent Application Laid-Open No. 2007-199653, Japanese Patent Application Laid-Open No. 2008-274250, Japanese Patent Application Laid-Open No. 2010-122656, Japanese Patent Application Laid-Open No. 2012-214720, Japanese Patent Application Laid-Open No. 2014-29435, International Publication WO2012 / 077640, International Publication WO2010 / 147155, International Publication WO2012 / 176767, Japanese Patent Application Laid-Open No. 2005-128509, Japanese Patent Application Laid-Open No. 2006-259249, Japanese Patent Application Laid-Open No. 2006-259482, Japanese Patent Application Laid-Open No. 2006-293298, Japanese Patent Application Laid-Open No. 2007-316282, Japanese Patent Application Laid-Open No. 2012-145897, Japanese Patent Application Laid-Open No. 2017-119671, Japanese Patent Application Laid-Open No. 2019-44022, etc.

[0095] The above-mentioned (A) organic lower layer film, for example, a composition solution containing the above-mentioned organic lower layer film material can be used and formed on a substrate to be processed by a spin coating method or the like. After forming the organic lower layer film by a spin coating method or the like, it is preferable to perform baking in order 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.

[0096] An organic hard mask formed by a CVD method or an ALD method instead of the coating method such as the above-mentioned spin coating method can also be adopted as the organic lower layer film. In the pattern forming method of the present invention, it is preferable that the organic lower layer film is formed by a CVD method.

[0097] By adopting an organic hard mask formed by a CVD method for the organic lower layer film, the resist pattern shape can be transferred to the substrate to be processed with higher precision. The organic hard mask formed by a CVD method shows higher resistance to dry etching using a fluorine-based gas compared to the organic lower layer film formed of a coating-type organic lower layer film material, so it is more useful for forming fine patterns.

[0098] The above-mentioned organic lower layer film is preferably formed of a film containing any one of a graphene film, an amorphous carbon film, and a diamond-like carbon film. Such a film can be formed by a CVD method, for example.

[0099] In the case of the pattern forming method using the above-mentioned organic lower layer film, compared to the organic lower layer film formed of a coating-type organic lower layer film material, it shows higher resistance to the fluorine-based gas used when dry etching the substrate to be processed, so the resist pattern shape can be transferred to the substrate to be processed with higher precision.

[0100] The thickness of the above-mentioned organic lower layer film is preferably 10 to 1,000 nm, more preferably 15 nm to 100 nm, and even more preferably 20 nm to 50 nm.

[0101] <(B) Silicon-containing hard mask (B layer)>

[0102] In the pattern forming method of the present invention, as the silicon-containing hard mask material that can be used for forming the (B) silicon-containing hard mask (B layer), for example, a polysiloxane-based resist intermediate film material can be used. For example, the materials described in Japanese Patent Publication No. 471603 and the like.

[0103] For known silicon-containing hard mask materials, in order to have an antireflection effect, it is preferable to use polysiloxanes in which phenyl groups, light-absorbing groups containing silicon-silicon bonds, etc. are suspended and crosslinked with an acid or heat. In the pattern formation method of the present invention, by making the silicon-containing antireflection film have an antireflection effect, reflection can be suppressed. For the silicon-containing hard mask material, a design that minimizes the organic groups that may deteriorate the dry etching resistance when dry etching the organic underlayer film with an oxygen-based gas and may deteriorate the pattern shape can be adopted, and high-precision processing of the substrate to be processed can be achieved.

[0104] For the above-mentioned silicon-containing hard mask, for example, a composition solution containing the above-mentioned silicon-containing hard mask material can be used, and it can be formed on the substrate to be processed by a spin coating method or the like. After forming the silicon-containing hard mask by a spin coating method or the like, it is preferable to perform baking to evaporate the organic solvent. Conditions within a baking temperature range of 100 to 600 °C and a baking time range of 10 to 300 seconds are preferable.

[0105] Alternatively, instead of using the above spin coating method or the like, a (B) silicon-containing hard mask (inorganic hard mask) can be formed by CVD method or ALD method. Specifically, it is preferable to form a layer selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxynitride film for the (B) silicon-containing hard mask. For example, examples of the formation method of a silicon nitride film are described in Japanese Patent Laid-Open No. 2002-334869 and International Publication No. 2004 / 066377.

[0106] In the pattern formation method of the present invention, it is preferable that the (B) silicon-containing hard mask is an inorganic hard mask formed by CVD method (a layer selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film).

[0107] If it is a pattern formation method of forming the above inorganic hard mask by CVD method as the (B) silicon-containing hard mask, it shows high resistance to the oxygen-based gas used for dry etching the organic underlayer film, so the resist pattern shape can be transferred to the substrate to be processed with high precision. Also, in the pattern formation method of the present invention, when using the above inorganic hard mask, it will exert an excellent effect from the viewpoint of suppressing the poisoning of the organic underlayer film and the substrate to be processed as the base to the photoresist layer, so it is useful for the formation of fine patterns.

[0108] It is preferable that the film thickness FTb of the (B) silicon-containing hard mask is in the range of 5 to 200 nm, and more preferably in the range of 10 to 100 nm.

[0109] Also, for the (B) silicon-containing hard mask, it is most preferable to use a silicon oxynitride film (SiON) with a high antireflection film effect. Since the substrate temperature when forming the SiON film is 300 to 500 °C, the organic underlayer film needs to be able to withstand a temperature of 300 to 500 °C.

[0110] <(C) Silicon-containing antireflection film (C layer)>

[0111] In the pattern forming method of the present invention, the silicon-containing antireflection film (C layer) (C) is formed using a composition for forming a silicon-containing antireflection film containing polysiloxane (Sx) and a crosslinking agent described in detail below.

[0112] (Polysiloxane (Sx))

[0113] The polysiloxane (Sx) contains any one or more of the repeating units represented by the following general formula (Sx-1), the repeating units represented by the following general formula (Sx-2), and the partial structure represented by the following general formula (Sx-3). Such a polysiloxane (Sx) is also called a thermally crosslinkable polysiloxane.

[0114] [Chemical formula 4]

[0115]

[0116] In the formula, R a , R b and R c are each independently a monovalent organic group having 1 to 30 carbon atoms.

[0117] The above polysiloxane (Sx) can be obtained, for example, by hydrolytic condensation of the following hydrolyzable monomers (Sm).

[0118] Hydrolyzable monomer (Sm), specifically, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, trimethoxysilane, triethoxysilane, tripropoxysilane, triisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane, propyltriisopropoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, isopropyltripropoxysilane, isopropyltriisopropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltripropoxysilane, butyltriisopropoxysilane, sec-butyltrimethoxysilane, sec-butyltriethoxysilane, sec-butyltripropoxysilane, sec-butyltriisopropoxysilane, tert-butyltrimethoxysilane, tert-butyltriethoxysilane, tert-butyltripropoxysilane, tert-butyltriisopropoxysilane, cyclopropyltrimethoxysilane, cyclopropyltriethoxysilane, cyclopropyltripropoxysilane, cyclopropyltriisopropoxysilane, cyclobutyltrimethoxysilane, cyclobutyltriethoxysilane, cyclobutyltripropoxysilane, cyclobutyltriisopropoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, cyclopentyltripropoxysilane, cyclopentyltriisopropoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexyltripropoxysilane, cyclohexyltriisopropoxysilane, cyclohexenyltrimethoxysilane, cyclohexenyltriethoxysilane, cyclohexenyltripropoxysilane, cyclohexenyltriisopropoxysilane, cyclohexenylethyltrimethoxysilane, cyclohexenylethyltriethoxysilane, cyclohexenylethyltripropoxysilane, cyclohexenylethyltriisopropoxysilane, cyclooctyltrimethoxysilane, cyclooctyltriethoxysilane, cyclooctyltripropoxysilane, cyclooctyltriisopropoxysilane, cyclopentadienylpropyltrimethoxysilane, cyclopentadienylpropyltriethoxysilane, cyclopentadienylpropyltripropoxysilane, cyclopentadienylpropyltriisopropoxysilane, bicycloheptenyltrimethoxysilane, bicycloheptenyltriethoxysilane, bicycloheptenyltripropoxysilane, bicycloheptenyltriisopropoxysilane, bicycloheptyltrimethoxysilane, bicycloheptyltriethoxysilane, bicycloheptyltripropoxysilane, bicycloheptyltriisopropoxysilane, adamantyltrimethoxysilane, adamantyltriethoxysilane, adamantyltripropoxysilane, adamantyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyltriisopropoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, benzyltripropoxysilane, benzyltriisopropoxysilane, anisyltrimethoxysilane, anisyltriethoxysilane, anisyltripropoxysilane,Anisyltriisopropoxysilane, Tolyltrimethoxysilane, Tolyltriethoxysilane, Tolyltripropoxysilane, Tolyltriisopropoxysilane, Phenethyltrimethoxysilane, Phenethyltriethoxysilane, Phenethyltripropoxysilane, Phenethyltriisopropoxysilane, Naphthyltrimethoxysilane, Naphthyltriethoxysilane, Naphthyltripropoxysilane, Naphthyltriisopropoxysilane, Dimethyldimethoxysilane, Dimethyldiethoxysilane, Methylethyldimethoxysilane, Methylethyldiethoxysilane, Dimethyldipropoxysilane, Dimethyldiisopropoxysilane, Diethyldimethoxysilane, Diethyldiethoxysilane, Diethyldipropoxysilane, Diethyldiisopropoxysilane, Dipropyldimethoxysilane, Dipropyldiethoxysilane, Dipropyldipropoxysilane, Dipropyldiisopropoxysilane, Diisopropyldimethoxysilane, Diisopropyldiethoxysilane, Diisopropyldipropoxysilane, Diisopropyldiisopropoxysilane, Dibutyldimethoxysilane, Dibutyldiethoxysilane, Dibutyldipropoxysilane, Dibutyldiisopropoxysilane, Di-sec-butyldimethoxysilane, Di-sec-butyldiethoxysilane, Di-sec-butyldipropoxysilane, Di-sec-butyldiisopropoxysilane, Di-tert-butyldimethoxysilane, Di-tert-butyldiethoxysilane, Di-tert-butyldipropoxysilane, Di-tert-butyldiisopropoxysilane, Dicyclopropyldimethoxysilane, Dicyclopropyldiethoxysilane, Dicyclopropyldipropoxysilane, Dicyclopropyldiisopropoxysilane, Dicyclobutyldimethoxysilane, Dicyclobutyldiethoxysilane, Dicyclobutyldipropoxysilane, Dicyclobutyldiisopropoxysilane, Dicyclopentyldimethoxysilane, Dicyclopentyldiethoxysilane, Dicyclopentyldipropoxysilane, Dicyclopentyldiisopropoxysilane, Dicyclohexyldimethoxysilane, Dicyclohexyldiethoxysilane, Dicyclohexyldipropoxysilane, Dicyclohexyldiisopropoxysilane, Dicyclohexenyldimethoxysilane, Dicyclohexenyldiethoxysilane, Dicyclohexenyldipropoxysilane, Dicyclohexenyldiisopropoxysilane, Dicyclohexenylethyldimethoxysilane, Dicyclohexenylethyldiethoxysilane, Dicyclohexenylethyldipropoxysilane, Dicyclohexenylethyldiisopropoxysilane, Dicyclooctyldimethoxysilane, Dicyclooctyldiethoxysilane, Dicyclooctyldipropoxysilane, Dicyclooctyldiisopropoxysilane, Dicyclopentadienylpropyldimethoxysilane, Dicyclopentadienylpropyldiethoxysilane, Dicyclopentadienylpropyldipropoxysilane, Dicyclopentadienylpropyldiisopropoxysilane, Bis(bicycloheptenyl)dimethoxysilane, Bis(bicycloheptenyl)diethoxysilane, Bis(bicycloheptenyl)dipropoxysilane, Bis(bicycloheptenyl)diisopropoxysilane, Bis(bicycloheptyl)dimethoxysilane, Bis(bicycloheptyl)diethoxysilane, Bis(bicycloheptyl)dipropoxysilane, Bis(bicycloheptyl)diisopropoxysilane, Diadamantyldimethoxysilane, Diadamantyldiethoxysilane, Diadamantyldipropoxysilane,Diadamantyl diisopropoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldipropoxysilane, diphenyldiisopropoxysilane, trimethylmethoxysilane, trimethylethoxysilane, dimethylethylmethoxysilane, dimethylethylethoxysilane, dimethylphenylmethoxysilane, dimethylphenylethoxysilane, dimethylbenzylmethoxysilane, dimethylbenzylethoxysilane, dimethylphenethylmethoxysilane, and dimethylphenethylethoxysilane, etc.

[0119] Desirable hydrolyzable monomers (Sm), such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexenyltrimethoxysilane, cyclohexenyltriethoxysilane, phenyltrimethoxysilane, phenyldiethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, phenethyltrimethoxysilane, phenethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, dipropyldimethoxysilane, dibutyldimethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, trimethylmethoxysilane, dimethylethylmethoxysilane, dimethylphenylmethoxysilane, dimethylbenzylmethoxysilane, and dimethylphenethylmethoxysilane, etc.

[0120] And regarding the above-mentioned R corresponding to the hydrolyzable monomer (Sm) in the compounds exemplified above a 、R b 、and R c For other examples of the organic groups represented, organic groups having one or more carbon-oxygen single bonds or carbon-oxygen double bonds can be cited. Specifically, organic groups having one or more groups selected from the group consisting of an ether bond, an ester bond, an alkoxy group, and a hydroxyl group, etc. Examples thereof are those represented by the following general formula (Sm-R).

[0121] (P-Q 1 -(S 1 ) v1 -Q 2 -) u -(T) v2 -Q 3-(S 2 ) v3 -Q 4 -

[0122] (Sm-R)

[0123] In the general formula (Sm-R), P is a hydrogen atom, a cyclic ether group, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an alkylcarbonyloxy group having 1 to 6 carbon atoms, or an alkylcarbonyl group having 1 to 6 carbon atoms, and Q 1 、Q 2 、Q 3 、and Q 4 are each independently -C q H (2q-p) P p -(wherein, P is as described above, p is an integer from 0 to 3, q is an integer from 0 to 10 (however, q = 0 represents a single bond).), u is an integer from 0 to 3, and S 1 and S 2 each independently represent -O-, -CO-, -OCO-, -COO-, or -OCOO-. v1, v2, and v3 each independently represent 0 or 1. T is a divalent group selected from the group consisting of divalent atoms other than carbon, alicyclic rings, aromatic rings, or heterocyclic rings. Examples of alicyclic rings, aromatic rings, or heterocyclic rings that may contain heteroatoms such as oxygen atoms for T are shown below. The positions where and Q 2 are bonded to Q 3 are not particularly limited, and can be appropriately selected considering factors such as reactivity due to steric factors and availability of commercially available reagents used in the reaction.

[0124] [Chemical formula 5]

[0125]

[0126] Ideal examples of organic groups having one or more carbon-oxygen single bonds or carbon-oxygen double bonds in the general formula (Sm-R) are listed below. Also, in the following formulas, (Si) is described to show the bonding position to Si.

[0127] [Chemical formula 6]

[0128]

[0129] [Chemical formula 7]

[0130]

[0131] Also, examples of the organic groups of R a 、R b 、and R c can also use organic groups containing a silicon-silicon bond. Specifically, they are listed below.

[0132] [Chemical formula 8]

[0133]

[0134] Further, for the organic groups of R a 、R b and R c Examples of the organic groups, organic groups having a protecting group decomposable by an acid can also be used. Specifically, for example, the organic groups described in paragraphs

[0043] to

[0048] of Japanese Patent Application Laid-Open No. 2013-167669, and the organic groups obtained from a silicon compound disclosed in paragraph

[0056] of Japanese Patent Application Laid-Open No. 2013-224279.

[0135] Further, for the organic groups of R a 、R b 、and R c Examples of the organic groups, organic groups having a fluorine atom can also be used. Specifically, the organic groups obtained from a silicon compound disclosed in paragraphs

[0059] to

[0065] of Japanese Patent Application Laid-Open No. 2012-53253 can be cited.

[0136] In the above hydrolyzable monomer (Sm), one, two, or three hydrolyzable groups such as chlorine, bromine, iodine, acetoxy, methoxy, ethoxy, propoxy, or butoxy are bonded to the silicon represented by (Si) in the above partial structure.

[0137] [Synthesis method of polysiloxane (Sx)]

[0138] (Synthesis method 1: Acid catalyst)

[0139] The polysiloxane (Sx) used in the pattern forming method of the present invention can be produced, for example, by subjecting a mixture of one or more hydrolyzable monomers (Sm) to hydrolysis condensation in the presence of an acid catalyst.

[0140] The acid catalyst used at this time is, for example, an organic acid such as formic acid, acetic acid, oxalic acid, maleic acid, methanesulfonic acid, benzenesulfonic acid, or toluenesulfonic acid, or an inorganic acid such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, perchloric acid, or phosphoric acid. The amount of the catalyst used can be 1×10 -6 to 10 moles, preferably 1×10 -5 to 5 moles, and more preferably 1×10 -4 to 1 mole, per 1 mole of the monomer.

[0141] When obtaining the polysiloxane (Sx) by hydrolysis condensation from these monomers, the amount of water can be added, for example, 0.01 to 100 moles, more preferably 0.05 to 50 moles, and still more preferably 0.1 to 30 moles, per 1 mole of the hydrolyzable substituent bonded to the monomer. If it is 100 moles or less, the apparatus used for the reaction is reduced, and there is economy.

[0142] Operating method, for example: monomers can be added to an aqueous solution of a catalyst to initiate a hydrolysis condensation reaction. At this time, an organic solvent can be added to the aqueous solution of the catalyst, the monomers can be diluted with an organic solvent, or both can be carried out. The reaction temperature can be set, for example, at 0 to 100 °C, preferably 5 to 80 °C. A method in which the temperature is maintained at 5 to 80 °C during the monomer addition and then aged at 20 to 80 °C is preferred.

[0143] Those that can be added to the aqueous solution of the catalyst or the organic solvent that can dilute the monomers are preferably methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, acetonitrile, tetrahydrofuran, toluene, hexane, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl amyl ketone, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monoterbutyl ether acetate, γ-butyrolactone, and mixtures thereof.

[0144] Among these solvents, water-soluble solvents are more desirable. For example: alcohols such as methanol, ethanol, 1-propanol, 2-propanol, polyols such as ethylene glycol and propylene glycol, polyol condensate derivatives such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl ether, acetone, acetonitrile, tetrahydrofuran, etc. Particularly desirable among them are solvents with a boiling point of 100 °C or lower.

[0145] Also, the amount of the organic solvent used can be set, for example, at 0 to 1,000 ml, particularly preferably 0 to 500 ml, relative to 1 mole of the monomers. If the amount of the organic solvent used is small, the reaction vessel can be reduced, which is economical.

[0146] After that, if necessary, a neutralization reaction of the catalyst is carried out to obtain an aqueous solution of the reaction mixture. At this time, the amount of the basic substance that can be used for neutralization is preferably 0.1 to 2 equivalents relative to the acid used as the catalyst. As long as this basic substance is basic in water, it can be any substance.

[0147] Then, it is preferable to remove by-products such as alcohols generated in the hydrolysis condensation reaction from the reaction mixture by reduced pressure or the like. At this time, the temperature at which the reaction mixture is heated depends on the types of the added organic solvents and the alcohols generated by the reaction, preferably 0 to 100°C, more preferably 10 to 90°C, and still more preferably 15 to 80°C. Also, the degree of reduced pressure at this time varies depending on the types of the organic solvents and alcohols to be removed, the exhaust device, the condensation device, and the heating temperature, preferably below atmospheric pressure, more preferably below an absolute pressure of 80 kPa, and still more preferably below an absolute pressure of 50 kPa. The amount of alcohol removed at this time is difficult to accurately determine, but it is desirable to remove 80 mass% or more of the generated alcohols and the like.

[0148] Then, the acid catalyst used in the hydrolysis condensation can also be removed from the reaction mixture. The method for removing the acid catalyst is to mix water with the polysiloxane solution and extract the polysiloxane with an organic solvent. The organic solvent used at this time is preferably one that can dissolve the polysiloxane and will form two layers when mixed with water. Specific examples of the organic solvent include, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl amyl ketone, butylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butylene glycol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monoterbutyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, cyclopentyl methyl ether, and mixtures thereof.

[0149] Alternatively, a mixture of a water-soluble organic solvent and a water-insoluble organic solvent can also be used. For example: methanol-ethyl acetate mixture, ethanol-ethyl acetate mixture, 1-propanol-ethyl acetate mixture, 2-propanol-ethyl acetate mixture, ethylene glycol monomethyl ether acetate-ethyl acetate mixture, propylene glycol monomethyl ether acetate-ethyl acetate mixture, ethylene glycol monomethyl ether-ethyl acetate mixture, ethylene glycol monoethyl ether acetate-ethyl acetate mixture, propylene glycol monoethyl ether acetate-ethyl acetate mixture, ethylene glycol monoethyl ether-ethyl acetate mixture, ethylene glycol monopropyl ether acetate-ethyl acetate mixture, propylene glycol monopropyl ether acetate-ethyl acetate mixture, ethylene glycol monopropyl ether-ethyl acetate mixture, methanol-methyl isobutyl ketone mixture, ethanol-methyl isobutyl ketone mixture, 1-propanol-methyl isobutyl ketone mixture, 2-propanol-methyl isobutyl ketone mixture, propylene glycol monomethyl ether acetate-methyl isobutyl ketone mixture, ethylene glycol monomethyl ether-methyl isobutyl ketone mixture, propylene glycol monoethyl ether acetate-methyl isobutyl ketone mixture, ethylene glycol monoethyl ether-methyl isobutyl ketone mixture, propylene glycol monopropyl ether acetate-methyl isobutyl ketone mixture, ethylene glycol monopropyl ether-methyl isobutyl ketone mixture, methanol-cyclopentyl methyl ether mixture, ethanol-cyclopentyl methyl ether mixture, 1-propanol-cyclopentyl methyl ether mixture, 2-propanol-cyclopentyl methyl ether mixture, propylene glycol monomethyl ether acetate-cyclopentyl methyl ether mixture, ethylene glycol monomethyl ether-cyclopentyl methyl ether mixture, propylene glycol monoethyl ether acetate-cyclopentyl methyl ether mixture, ethylene glycol monoethyl ether-cyclopentyl methyl ether mixture, propylene glycol monopropyl ether acetate-cyclopentyl methyl ether mixture, ethylene glycol monopropyl ether-cyclopentyl methyl ether mixture, methanol-propylene glycol methyl ether acetate mixture, ethanol-propylene glycol methyl ether acetate mixture, 1-propanol-propylene glycol methyl ether acetate mixture, 2-propanol-propylene glycol methyl ether acetate mixture, propylene glycol monomethyl ether-propylene glycol methyl ether acetate mixture, ethylene glycol monomethyl ether-propylene glycol methyl ether acetate mixture, propylene glycol monoethyl ether-propylene glycol methyl ether acetate mixture, ethylene glycol monoethyl ether-propylene glycol methyl ether acetate mixture, propylene glycol monopropyl ether-propylene glycol methyl ether acetate mixture, ethylene glycol monopropyl ether-propylene glycol methyl ether acetate mixture, etc. are preferred, but the combination is not limited to these.

[0150] Alternatively, the mixing ratio of the water-soluble organic solvent and the water-insoluble organic solvent can be appropriately selected. For 100 parts by mass of the water-insoluble organic solvent, for example, the water-soluble organic solvent can be set to 0.1 to 1,000 parts by mass, preferably 1 to 500 parts by mass, and more preferably 2 to 100 parts by mass.

[0151] Then, it can also be washed with neutral water. This water is usually deionized water or ultrapure water. The amount of this water is preferably 0.01 to 100 L, more preferably 0.05 to 50 L, and even more preferably 0.1 to 5 L relative to 1 L of the thermally crosslinkable polysiloxane solution. For this washing method, the two can be placed in the same container, stirred and mixed, and then left standing to separate the water layer. The number of washing times can be 1 or more, but since washing 10 or more times may not necessarily achieve the corresponding washing effect, it is preferably about 1 to 5 times.

[0152] Other methods for removing the acid catalyst include, for example, using an ion exchange resin, or neutralizing with an epoxide such as ethylene oxide or propylene oxide and then removing it. These methods can be appropriately selected according to the acid catalyst used in the reaction.

[0153] During the water washing operation at this time, a part of the thermally crosslinkable polysiloxane will escape into the water layer, and sometimes an effect substantially equivalent to the fractionation operation can be obtained. Therefore, the number of water washing times and the amount of washing water can be appropriately selected according to the catalyst removal effect and the fractionation effect.

[0154] In either case of the thermally crosslinkable polysiloxane solution with the acid catalyst remaining and the polysiloxane solution with the acid catalyst removed, by adding the final solvent and performing solvent exchange under reduced pressure, a desired polysiloxane solution can be obtained. At this time, the temperature of the solvent exchange depends on the types of the reaction solvent and the extraction solvent to be removed, and is preferably 0 to 100 °C, more preferably 10 to 90 °C, and even more preferably 15 to 80 °C. Also, the degree of reduced pressure at this time varies depending on the type of the extraction solvent to be removed, the exhaust device, the condensation device, and the heating temperature, and is preferably below atmospheric pressure, more preferably 80 kPa or less in terms of absolute pressure, and even more preferably 50 kPa or less in terms of absolute pressure.

[0155] At this time, the thermally crosslinkable polysiloxane may become unstable when the solvent is changed. This occurs depending on the compatibility of the final solvent with the polysiloxane. To prevent this, a monohydric or polyhydric alcohol having a cyclic ether as a substituent described in paragraphs (0181) to (0182) of Japanese Patent Application Laid-Open No. 2009-126940 can also be added as a stabilizer. The addition amount is 0 to 25 parts by mass, preferably 0 to 15 parts by mass, more preferably 0 to 5 parts by mass, relative to 100 parts by mass of the thermally crosslinkable polysiloxane in the solution before the solvent exchange, but when added, it is preferably 0.5 part by mass or more. If necessary, a monohydric or polyhydric alcohol having a cyclic ether as a substituent can also be added to the solution before the solvent exchange, and then the solvent exchange operation can be carried out.

[0156] If the polysiloxane is concentrated above a certain concentration, there is a concern that the condensation reaction will proceed further and change to a state where it is no longer soluble in organic solvents. Therefore, it is advisable to prepare a solution state with an appropriate concentration in advance. Also, if it is too dilute, the amount of solvent becomes excessive. Therefore, it is more economical and ideal to prepare a solution state with an appropriate concentration in advance. The concentration at this time should be 0.1 to 20% by mass.

[0157] The final solvent added to the thermally crosslinkable polysiloxane solution should be an alcohol-based solvent. Particularly ideal ones are, for example, monoalkyl ether derivatives such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and butanediol. Specifically, for example, butylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butylene glycol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, diacetone alcohol, etc.

[0158] If these solvents are the main components, a non-alcohol-based solvent can also be added as an auxiliary solvent. Examples of the auxiliary solvent include acetone, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl amyl ketone, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monoterbutyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, cyclopentyl methyl ether, etc.

[0159] Also, in another reaction operation using an acid catalyst, water or a water-containing organic solvent can be added to the monomer or the organic solution of the monomer to start the hydrolysis reaction. At this time, the catalyst can be added to the monomer or the organic solution of the monomer, or can be added to the water or the water-containing organic solvent. The reaction temperature is, for example, 0 to 100 °C, preferably 10 to 80 °C. A method of heating to 10 to 50 °C when dropping water and then raising the temperature to 20 to 80 °C for aging is preferred.

[0160] When using an organic solvent, it should be water-soluble, and examples include: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, tetrahydrofuran, acetonitrile, butylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butylene glycol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butylene glycol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and polyol condensate derivatives such as propylene glycol monopropyl ether and mixtures thereof.

[0161] The amount of the organic solvent used is 0 to 1,000 ml, preferably 0 to 500 ml, per mole of monomer 1. When the amount of the organic solvent used is small, the reaction vessel is smaller and more economical. The post-treatment of the obtained reaction mixture can be carried out in the same manner as the above method to obtain a polysiloxane.

[0162] (Synthesis method 2: base catalyst)

[0163] In addition, the polysiloxane (Sx) can be produced by subjecting a mixture of one or more hydrolyzable monomers (Sm) to hydrolysis and condensation in the presence of a base catalyst.

[0164] The base catalyst used at this time is, for example, methylamine, ethylamine, propylamine, butylamine, ethylenediamine, hexamethylenediamine, dimethylamine, diethylamine, ethylmethylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, cyclohexylamine, dicyclohexylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicyclooctane, diazabicyclononene, diazabicycloundecene, hexamethylenetetramine, aniline, N,N-dimethylaniline, pyridine, N,N-dimethylaminopyridine, pyrrole, piperazine, pyrrolidine, piperidine, methylpyridine, tetramethylammonium hydroxide, choline hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, ammonia, lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, etc. The amount of the catalyst used is, for example, 1×10 -6 moles to 10 moles, preferably 1×10 -5 moles to 5 moles, and more preferably 1×10 -4 moles to 1 mole, per mole of the silicon monomer.

[0165] When obtaining a thermally crosslinkable polysiloxane by hydrolysis and condensation from the above monomers, the amount of water is preferably 0.1 to 50 moles per 1 mole of the hydrolyzable substituent bonded to the monomer. If it is 50 moles or less, the apparatus used for the reaction is smaller and more economical.

[0166] The operation method is to add the monomer to the catalyst aqueous solution to start the hydrolysis and condensation reaction. At this time, an organic solvent can also be added to the catalyst aqueous solution, the monomer can be diluted with an organic solvent, or both can be carried out. The reaction temperature can be set, for example, at 0 to 100 °C, preferably 5 to 80 °C. A method in which the temperature is maintained at 5 to 80 °C during the dropwise addition of the monomer and then aged at 20 to 80 °C is preferred.

[0167] The organic solvent that can be added to the base catalyst aqueous solution or the organic solvent that can dilute the monomer is preferably the same as those exemplified as the organic solvents that can be added to the acid catalyst aqueous solution. In addition, in order to carry out the reaction economically, the amount of the organic solvent used is preferably 0 to 1,000 ml per mole of the monomer.

[0168] Thereafter, if necessary, a neutralization reaction of the catalyst is carried out to obtain an aqueous solution of the reaction mixture. At this time, the amount of the acidic substance that can be used for neutralization is preferably 0.1 to 2 equivalents relative to the basic substance used for the catalyst. If the acidic substance is acidic in water, it can be any substance.

[0169] Then, by-products such as alcohols generated by the hydrolysis condensation reaction are preferably removed from the reaction mixture by means of reduced pressure removal or the like. At this time, the temperature for heating the reaction mixture depends on the types of the organic solvent added and the alcohol generated by the reaction, but it is preferably 0 to 100°C, more preferably 10 to 90°C, and still more preferably 15 to 80°C. Also, the degree of reduced pressure at this time varies depending on the types of the organic solvent and alcohol to be removed, the exhaust device, the condensation device, and the heating temperature, and it is preferably below atmospheric pressure, more preferably 80 kPa or less in terms of absolute pressure, and still more preferably 50 kPa or less in terms of absolute pressure. Although it is not easy to correctly know the amount of alcohol removed at this time, it is desirable to remove about 80% by mass or more of the generated alcohol.

[0170] Then, in order to remove the catalyst used for hydrolysis condensation, the polysiloxane is extracted with an organic solvent. The organic solvent used at this time is preferably one that can dissolve the polysiloxane and will separate into two layers when mixed with water. Examples of the organic solvent include: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monoter-butyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, cyclopentyl methyl ether, and mixtures thereof, etc.

[0171] A mixture of a water-soluble organic solvent and a water-insoluble organic solvent can also be used.

[0172] Specific examples of the organic solvent used for removing the base catalyst can be the above-mentioned organic solvents specifically exemplified as those used for removing the acid catalyst, or those similar to the mixture of the water-soluble organic solvent and the water-insoluble organic solvent.

[0173] In addition, the mixing ratio of the water-soluble organic solvent and the water-insoluble organic solvent can be appropriately selected. The water-soluble organic solvent can be 0.1 to 1,000 parts by mass, preferably 1 to 500 parts by mass, and more preferably 2 to 100 parts by mass relative to 100 parts by mass of the water-insoluble organic solvent.

[0174] Then, it is washed with neutral water. This water may be what is commonly called deionized water, ultrapure water, etc. The amount of this water is, for example, 0.01 to 100 L, preferably 0.05 to 50 L, and more preferably 0.1 to 5 L relative to 1 L of the thermally crosslinkable polysiloxane solution. The washing method may be to put the two into the same container, stir, and then let it stand to separate the water layer. The number of washing times may be 1 or more. Even if it is washed more than 10 times, no corresponding washing effect can be obtained. Therefore, it is preferably about 1 to 5 times.

[0175] Add the final solvent to the washed polysiloxane solution and perform solvent exchange under reduced pressure to obtain the desired polysiloxane solution. At this time, the temperature of the solvent exchange depends on the type of extraction solvent to be removed, and is preferably 0 to 100 °C, more preferably 10 to 90 °C, and even more preferably 15 to 80 °C. Also, the degree of reduced pressure at this time varies depending on the type of extraction solvent to be removed, the exhaust device, the condensation device, and the heating temperature, and is preferably below atmospheric pressure, more preferably 80 kPa or less in terms of absolute pressure, and even more preferably 50 kPa or less in terms of absolute pressure.

[0176] The final solvent added to the polysiloxane solution is preferably an alcohol-based solvent, and particularly preferably monoalkyl ethers such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, etc. 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, etc. are preferred.

[0177] Another reaction operation using an alkali catalyst is to add water or a water-containing organic solvent to the monomer or the organic solution of the monomer to start the hydrolysis reaction. At this time, the catalyst can be added to the monomer or the organic solution of the monomer, or can be added to the water or the water-containing organic solvent. The reaction temperature can be set, for example, to 0 to 100 °C, preferably 10 to 80 °C. A method of heating to 10 to 50 °C during the dropwise addition of water and then raising the temperature to 20 to 80 °C for aging is preferred.

[0178] The organic solvent that can be used as the organic solution or the water-containing organic solvent of the monomer is preferably water-soluble, and examples include: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, tetrahydrofuran, acetonitrile, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether, etc., polyol condensate derivatives, and mixtures thereof.

[0179] The molecular weight of the polysiloxane obtained by using the above synthesis method 1 or 2 can be adjusted not only by the selection of monomers, but also by controlling the reaction conditions during polymerization. It is preferably used with a weight average molecular weight (Mw) of 100,000 or less, more preferably 200 to 50,000, and still more preferably 300 to 30,000. When using a weight average molecular weight of 100,000 or less, there will be no generation of foreign substances and no occurrence of coating unevenness. In addition, the data related to the above weight average molecular weight is represented by polystyrene conversion using gel permeation chromatography (GPC) with RI as the detector and tetrahydrofuran as the elution solvent, and using polystyrene as the standard substance.

[0180] The physical properties of the thermally crosslinkable polysiloxane used in the present invention vary depending on the type of acid or base catalyst used during hydrolysis and condensation and the reaction conditions. Therefore, it can be appropriately selected according to the performance of the resist underlayer film as the purpose.

[0181] Furthermore, a mixture of one or more hydrolyzable monomers (Sm) and a hydrolyzable metal compound represented by the following general formula (Mm) can be used as a component of the composition for forming a resist underlayer film, which is prepared under the conditions of using the aforementioned acid or base catalyst.

[0182] [Chemical formula 9]

[0183] U(OR 7 ) m7 (OR 8 ) m8 (Mm)

[0184] In the formula, R 7 and R 8 are each independently an organic group having 1 to 30 carbon atoms, m7 + m8 is the same number as the valence determined by the type of U, m7 and m8 are integers of 0 or more, and U is an element of Group III, IV, or V of the periodic table excluding carbon and silicon.

[0185] The hydrolyzable metal compound represented by the above general formula (Mm) includes, for example, metal alkoxides such as boron, aluminum, gallium, yttrium, germanium, titanium, and hafnium. Specifically, those described in

[0107] to

[0123] of Japanese Patent Application Laid-Open No. 2020-118960 can be used.

[0186] (Crosslinking agent)

[0187] In the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention, a crosslinking agent is added in order to improve the denseness of the antireflection film, prevent the movement of alkali components that may be generated from the silicon-containing hard mask to the photoresist film, and reduce the sensitivity and resolution of the resist and enhance the poisoning inhibition effect.

[0188] There are no special restrictions on the crosslinking agent, and various well-known crosslinking agents for various systems can be widely used. For example, melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, and phenol-based crosslinking agents. The above crosslinking agents can be used alone or in combination of two or more. The addition amount of the crosslinking agent when added is preferably 5 to 50 parts, more preferably 10 to 40 parts, and still more preferably 10 to 30 parts, relative to 100 parts of the composition for forming the silicon-containing antireflection film. If the addition amount is 5 parts or more, sufficient hardening properties will be exhibited, and poisoning of the photoresist film can be suppressed. On the other hand, if the addition amount is 50 parts or less, there is no risk of deterioration of dry etching resistance due to a decrease in the ratio of silicon in the composition.

[0189] The above crosslinking agent is preferably a compound containing an isocyanuric acid structure, and the structure of the following formula (A-1) is more preferable.

[0190] [Chemical formula 10]

[0191]

[0192] In the above formula, X 1 , X 2 and R 3 each independently represent a methyl group, an ethyl group, a propyl group, an allyl group, a propargyl group, or a group represented by the following formula (A-2).

[0193] [Chemical formula 11]

[0194]

[0195] In the above formula, R 1 represents a methyl group, an ethyl group, a propyl group, an allyl group, or a propargyl group, R 2 represents a hydrogen atom, an acetyl group, an acryloyl group, a methacryloyl group, a benzoyl group, a naphthoyl group, or an anthraniloyl group, and * represents the bonding site.

[0196] If the crosslinking agent is a compound containing the above structure, when added to the composition for forming the silicon-containing antireflection film, it can be crosslinked with polysiloxane by baking, thereby forming a dense film. Therefore, a silicon-containing antireflection film (C) showing an excellent poisoning suppression effect can be formed. Moreover, the adhesion to the photoresist film (upper resist film) can be further improved, the collapse suppression effect of ultra-fine patterns is higher, and a resist pattern with a better pattern shape can be formed.

[0197] Specifically, the following structures can be cited as ideal structures. R 3 As described above.

[0198] [Chemical formula 12]

[0199]

[0200] [Chemical formula 13]

[0201]

[0202] [Chemical formula 14]

[0203]

[0204] [Chemical formula 15]

[0205]

[0206] [Chemical formula 16]

[0207]

[0208] Examples of the structure represented by the above general formula (A-2) include the following, etc.

[0209] [Chemical formula 17]

[0210]

[0211] [Chemical formula 18]

[0212]

[0213] Ideal examples of the compound represented by the above general formula (A-1) include the following, etc. Specifically, R 1 is preferably allyl or propargyl, R 2 is preferably a hydrogen atom, acetyl group, or acrylic group, R 3 is preferably allyl or a group represented by the above general formula (A-2), R 1 is more preferably allyl or propargyl, R 2 is more preferably a hydrogen atom or acetyl group, R 3 is more preferably allyl.

[0214] [Chemical formula 19]

[0215]

[0216] [Chemical formula 20]

[0217]

[0218] (Acid generator)

[0219] In the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention, one or more acid generators may be further incorporated. As the acid generator, any substance that acts as an acid precursor such as a thermal acid generator, a photoacid generator, or an acid proliferator can be used. However, in the present invention, the incorporated acid generator is preferably a sulfonium salt and a photoacid generator that generates acid by the action of high-energy rays. Specifically, the materials described in paragraphs

[0061] to

[0085] of Japanese Patent Application Laid-Open No. 2007-199653 can be added, but are not limited thereto.

[0220] The above acid generators can be used alone or in combination of two or more. When adding the acid generator, the addition amount is preferably 0.05 to 50 parts, more preferably 0.1 to 10 parts, relative to 100 parts of the thermally crosslinkable polysiloxane.

[0221] 〔Other components〕

[0222] (Crosslinking catalyst)

[0223] In the present invention, a crosslinking catalyst (Xc) may also be incorporated into the composition for forming a silicon-containing antireflection film. Examples of the crosslinking catalyst that can be incorporated include compounds represented by the following general formula (Xc0).

[0224] L a H b A(Xc0)

[0225] In the formula, L is lithium, sodium, potassium, rubidium, cesium, sulfonium, iodonium, phosphonium, or ammonium. A is a non-nucleophilic counterion. a is an integer of 1 or more, b is 0 or an integer of 1 or more, and a + b is the valence of the non-nucleophilic counterion.

[0226] Specifically, for the crosslinking catalyst (Xc0) that can be used in the present invention, examples include sulfonium salts having a structure represented by the following general formula (Xc-1), iodonium salts having the following general formula (Xc-2), phosphonium salts having the following general formula (Xc-3), ammonium salts having the following general formula (Xc-4), alkali metal salts, etc., and polysiloxanes of ammonium salts, sulfonium salts, phosphonium salts, and iodonium salts (Xc-10). Specifically, the materials described in paragraphs

[0124] to

[0163] of Japanese Patent Application Laid-Open No. 2020-118960 can be added.

[0227] [Chemical formula 21]

[0228]

[0229] [Chemical formula 22]

[0230]

[0231] In the above formula, R 204 、R 205 、R 206, and R 207 each represents a linear, branched or cyclic alkyl, alkenyl, oxoalkyl or oxoalkenyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or an aralkyl or aryloxoalkyl group having 7 to 12 carbon atoms, and part or all of the hydrogen atoms of these groups may also be substituted with alkoxy groups or the like. Also, R 205 and R 206 may also form a ring. When forming a ring, R 205 and R 206 each represents an alkylene group having 1 to 6 carbon atoms. A - represents a non-nucleophilic counterion. R 208 , R 209 , R 210 , and R 211 and R 204 , R 205 , R 206 , and R 207 are the same, but may also be hydrogen atoms. R 208 and R 209 , or R 208 , R 209 , and R 210 may also form a ring. When forming a ring, R 208 and R 209 , or R 208 , R 209 , and R 210 represent an alkylene group having 3 to 10 carbon atoms.

[0232] The above crosslinking catalysts (Xc-1), (Xc-2), (Xc-3), (Xc-4), and (Xc-10) can be used alone or in combination of two or more. The addition amount of the crosslinking catalyst is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, based on 100 parts by mass of the base polymer (for example, the thermally crosslinkable polysiloxane (Sx) obtained by the above method).

[0233] In the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention, the following raw materials may also be further incorporated.

[0234] (Organic acid)

[0235] In order to improve the stability of the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention, it is preferable to add a monovalent or divalent or higher organic acid having 1 to 30 carbon atoms. The acids added at this time include, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, stearic acid, linoleic acid, linolenic acid, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, trifluoroacetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, oxalic acid, malonic acid, methylmalonic acid, ethylmalonic acid, propylmalonic acid, butylmalonic acid, dimethylmalonic acid, diethylmalonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, citric acid, etc. In particular, oxalic acid, maleic acid, formic acid, acetic acid, propionic acid, citric acid, etc. are preferable. Also, in order to ensure stability, two or more acids may be mixed and used.

[0236] The addition amount of the organic acid is, for example, 0.001 to 25 parts by mass, preferably 0.01 to 15 parts by mass, and more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the thermally crosslinkable polysiloxane contained in the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention.

[0237] Alternatively, the above organic acid may be blended so that the pH of the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention is preferably 0 ≤ pH ≤ 7, more preferably 0.3 ≤ pH ≤ 6.5, and even more preferably 0.5 ≤ pH ≤ 6.

[0238] (Water)

[0239] Water can be added to the composition for forming a silicon-containing antireflection film of the present invention. If water is added, the polysiloxane compound in the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention will be hydrated, thus improving the lithography performance. In the solvent component of the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention, the water content rate is preferably more than 0 mass% and less than 50 mass%, particularly preferably 0.3 to 30 mass%, and even more preferably 0.5 to 20 mass%. If the addition amount of water is within the above range, the uniformity of the silicon-containing antireflection film is good, there is no risk of forming eye holes, and there is no risk of reducing the lithography performance.

[0240] The usage amount of all the solvents containing water can be, for example, 100 to 100,000 parts by mass relative to 100 parts by mass of the base polymer polysiloxane (Sx), and particularly preferably 200 to 50,000 parts by mass.

[0241] (Stabilizer)

[0242] Furthermore, a stabilizer can be added to the composition for forming a silicon-containing antireflection film in the present invention. As the stabilizer, for example, a monohydric or polyhydric alcohol having a cyclic ether as a substituent can be added. In particular, if the stabilizer described in paragraphs

[0181] to

[0182] of Japanese Patent Application Laid-Open No. 2009-126940 is added, the stability of the composition for forming a silicon-containing antireflection film can be improved.

[0243] The addition amount of the stabilizer can be, for example, 0.001 to 50 parts by mass, particularly preferably 0.01 to 40 parts by mass, relative to 100 parts by mass of the base polymer polysiloxane (Sx).

[0244] (Surfactant)

[0245] Furthermore, a surfactant can be incorporated into the composition for forming a silicon-containing antireflection film as needed in the present invention. As such a surfactant, specifically, the material described in paragraph

[0185] of Japanese Patent Application Laid-Open No. 2009-126940 can be added.

[0246] The addition amount of the surfactant can be set to, for example, 0.001 to 5 parts by mass, particularly preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the base polymer polysiloxane (Sx).

[0247] (High-boiling solvent)

[0248] Furthermore, a high-boiling solvent having a boiling point of 180 °C or higher can be added to the composition for forming a silicon-containing antireflection film as needed in the present invention. Such high-boiling solvents include, for example, 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propanediol, 1,3-butanediol, 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, glycerol, γ-butyrolactone, tripropylene glycol monomethyl ether, diacetone alcohol, n-nonyl acetate, ethylene glycol monoethyl ether acetate, 1,2-diacetoxyethane, 1-acetoxy-2-methoxyethane, 1,2-diacetoxypropane, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monon-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, etc.

[0249] The addition amount of the high-boiling solvent can be, for example, 5 to 200 parts by mass, particularly preferably 10 to 100 parts by mass, relative to 100 parts by mass of the base polymer polysiloxane (Sx).

[0250] The above-mentioned (C) silicon-containing antireflection film, for example, the composition for forming the above-mentioned silicon-containing antireflection film can be used to form it on the (B) silicon-containing hard mask by spin coating or the like. After forming the (C) silicon-containing antireflection film by spin coating or the like, it is preferable to perform baking to evaporate the organic solvent. The baking temperature is preferably 100 to 600 °C, more preferably 150 °C to 350 °C. The baking time is preferably 10 to 300 seconds, more preferably 30 seconds to 180 seconds.

[0251] It is preferable that the thickness FTc of the (C) silicon-containing antireflection film (C layer) is thinner than the film thickness FTb of the (B) silicon-containing hard mask (B layer) (FTb > FTc). Specifically, the film thickness is preferably 1 to 15 nm, more preferably 1 to 12 nm, and even more preferably 1 to 10 nm. That is, it is advisable to form the (C) silicon-containing antireflection film so that the film thickness FTc of the (C) silicon-containing antireflection film is 15 nm or less.

[0252] If the silicon-containing antireflection film is within the above film thickness range, when the resist pattern formed on the (D) photoresist film is used as a mask to process the (C) silicon-containing antireflection film by dry etching using a fluorine-based gas, the film loss of the resist pattern can be minimized. Therefore, in the next step, when the pattern including the (D) photoresist film and the (C) silicon-containing antireflection film is used as a mask to process the (B) silicon-containing hard mask by dry etching using a fluorine-based gas, the resist pattern can be transferred to the (B) silicon-containing hard mask with high precision.

[0253] The proportion (b) of silicon in the (C) silicon-containing antireflection film measured by RBS (Rutherford backscattering spectrometry) is preferably 5 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 5 to 20% by mass. If the proportion (b) of silicon in the (C) silicon-containing antireflection film is 5% by mass or more, a film with a high refractive index can be formed, and the antireflection effect can be improved. If the proportion (b) of silicon in the (C) silicon-containing antireflection film is 30% by mass or less, the high-speed etching rate of the fluorine-based gas can be suppressed, and the selectivity with the (B) silicon-containing hard mask (B layer) can be improved.

[0254] If it is the above manufacturing method, the etching rate of the (C) silicon-containing antireflection film (C layer) with respect to the fluorine-based gas is slower than that of the (B) silicon-containing hard mask (B layer). Therefore, the resist pattern shape can be transferred to the (B) silicon-containing hard mask (B layer) with high precision.

[0255] <(D) photoresist film (D layer)>

[0256] In the pattern formation method of the present invention, the composition for a photoresist film used to form a photoresist film is not particularly limited, and it is preferably composed of a chemically amplified photoresist composition. Also, in the present invention, either positive development with an alkaline developer or negative development with a developer using an organic solvent can be employed. Therefore, a positive photoresist film material or a negative photoresist film material can be appropriately selected according to the development method.

[0257] (D) The thickness of the film is not particularly limited, and is preferably 10 to 500 nm, particularly preferably 20 to 200 nm.

[0258] Also, the composition for a photoresist film may also contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, Zn. When forming a photoresist film using the above composition for a photoresist film, the forming method may be a spin coating method or a method of forming by vapor deposition treatment using CVD or ALD.

[0259] When forming the (D) photoresist film by vapor deposition treatment using CVD or ALD, the above composition for a photoresist film is an EUV-sensitive metal oxide film, and the above metals are selected from Sn, Zr, Hf, Ti, Bi, Sb, etc., and Sn with excellent EUV sensitivity is preferably used. The film containing a metal oxide may be a photosensitive organometallic oxide film such as an organotin oxide (e.g., haloalkyl Sn, alkoxyalkyl Sn, or amidoalkyl Sn). Some specific examples of suitable precursors include trimethyltin chloride, dimethylditin dichloride, methyltin trichloride, tris(dimethylamino)methyltin(IV), and (dimethylamino)trimethyltin(IV).

[0260] For the metal oxide film, for example, a Lam Vector (registered trademark) tool can be used, and vapor deposition can be carried out using PECVD or PEALD. In the ALD example, the Sn oxide precursor is separated from the O precursor / plasma. The vapor deposition temperature is preferably in the range of 50 °C to 600 °C. The vapor deposition pressure is preferably between 100 and 6000 mTorr. The flow rate of the precursor liquid of the film containing a metal oxide (e.g., the organotin oxide precursor) can be 0.01 to 10 cmm, and the gas flow rate (CO 2 、CO、Ar、N 2 etc.) can be 100 to 10000 sccm. For the plasma power, high-frequency plasma (e.g., 13.56 MHz, 27.1 MHz, or higher frequency) can be used, and for a 300 mm wafer station, it is 200 to 1000 W. The vapor deposition thickness is preferably 100 to 2000 Å.

[0261] [(2) Step of forming a resist pattern]

[0262] In this step, the patterned circuit region of the (D) photoresist film is exposed to form an exposed pattern, and then the exposed pattern is developed with a developer to form a resist pattern on the (D) photoresist film.

[0263] In the positive pattern forming method, a (D) photoresist film is formed, exposed after heat treatment, and usually developed with an alkaline developer to obtain a positive resist pattern. Also, it is preferable to perform post-exposure bake (PEB) after exposure.

[0264] Regarding this alkaline developer, an aqueous solution of tetramethylammonium hydroxide (TMAH) etc. can be used.

[0265] Also, in the negative pattern forming method, a (D) photoresist is formed, exposed after heat treatment, and usually developed with an organic solvent to obtain a negative resist pattern. Also, it is preferable to perform PEB after exposure.

[0266] As the developer of this organic solvent, a developer containing one or more selected from 4-methyl-2-pentanol, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, phenyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. can be used.

[0267] The exposure light, for example: high-energy rays with a wavelength of 300 nm or less, specifically, excimer lasers of 248 nm, 193 nm, 157 nm, soft X-rays of 3 - 20 nm, electron beams, X-rays, etc.

[0268] Regarding the above method for forming a pattern of the resist upper layer film, it is preferable to form a pattern by optical lithography with a wavelength of 5 nm or more and 300 nm or less, direct drawing using an electron beam, nanoimprinting, or a combination of these.

[0269] [(3) Step of forming a pattern of the hard mask intermediate film]

[0270] In this step, the obtained resist pattern is used as an etching mask to etch the (C) silicon-containing antireflection film and the (B) silicon-containing hard mask intermediate film to form a pattern of the hard mask intermediate film.

[0271] In this step, for example, the resist pattern can be used as an etching mask to dry-etch the silicon-containing antireflection film (layer C) and the hard mask (layer B) using a fluorine-based gas.

[0272] [(4) Step of forming the organic underlayer film pattern]

[0273] In this step, the obtained hard mask intermediate film pattern is used as an etching mask to etch the (A) organic underlayer film to form an organic underlayer film pattern.

[0274] In this step, for example, the rigid mask pattern is used as an etching mask to dry-etch the (A) organic underlayer film (layer A) using an oxygen-based gas.

[0275] [(5) Step of forming a pattern on the substrate to be processed]

[0276] In this step, the obtained organic underlayer film pattern is used as an etching mask to pattern the substrate to be processed and form a pattern on the substrate to be processed.

[0277] In this step, for example, the organic underlayer film pattern can be used as an etching mask to process the substrate to be processed by dry-etching using a fluorine-based gas.

[0278] In the present invention, the object to be processed (substrate to be processed) is not particularly limited, and substrates such as Si, α-Si, p-Si, SiO 2 , SiN, SiON, W, TiN, Al, etc., or those with a processed layer formed on the substrate can be used. The processed layer can use various Low-k films such as Si, SiO 2 , SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si, etc. and their barrier films, and generally a thickness of 30 to 10,000 nm, particularly 50 to 5,000 nm can be formed. Also, when forming the processed layer, different materials can be used for the substrate and the processed layer.

[0279] Here, Figure 1 , an example of a pattern formation method using the above three-layer resist process is described. In this example, first, as Figure 1 (A), an organic underlayer film 3 is formed on the processed layer 2 of the substrate to be processed 10 composed of the substrate 1 and the processed layer 2 thereon using an organic underlayer film material. Next, a silicon-containing hard mask 4 is formed on the organic underlayer film 3. Next, a silicon-containing antireflection film 5 is formed on the silicon-containing hard mask 4 using a composition for forming a silicon-containing antireflection film. Next, a resist upper layer film 6 is formed on the silicon-containing antireflection film 5 using a photoresist material. Then, as Figure 1 (B), the exposed portion 7 of the photoresist film 6 is pattern-exposed. Then, as Figure 1of (C), develop with a developer solution, and form a resist pattern 6a on the upper layer of the resist. Then, as shown in Figure 1 of (D), use the resist pattern 6a as a mask, and transfer the pattern to the silicon-containing anti-reflection film 5 and the silicon-containing hard mask 4 by dry etching to obtain an anti-reflection film pattern 5a and a hard mask intermediate film pattern 4a. Then, as shown in Figure 1 of (E), use the hard mask intermediate film pattern 4a as a mask, and transfer the pattern to the organic lower layer film 3 by dry etching to obtain an organic lower layer film pattern 3a. And, as shown in Figure 1 of (F), use the organic lower layer film pattern 3a as a mask, process the processed layer 2 on the substrate 1, and form a pattern 2a on the processed substrate 10.

[0280] Also, Figure 2 is an example of a pattern formation method using a three-layer resist process for a comparative example. Figure 2 The pattern formation method of the example shown has a significant difference from the pattern formation method of the example in that a silicon-containing anti-reflection film is not formed and Figure 1 of the example. As shown in Figure 2 the three-layer process shown has a problem that it is technically difficult to balance the high refractive index of the silicon-containing hard mask and the dry etching resistance.

[0281] [Examples]

[0282] The following gives synthesis examples, examples, and comparative examples for a more specific description of the present invention, but the present invention is not limited by these.

[0283] [Synthesis Example] Synthesis of Thermally Crosslinkable Polysiloxanes (C1) to (C3)

[0284] (Synthesis Example 1)

[0285] Synthesis of Polysiloxane (C1) for Silicon-Containing Anti-Reflection Film

[0286] [Chemical Formula 23]

[0287]

[0288] Add 120 g of methanol, 0.1 g of 10% nitric acid, and 60 g of ultrapure water, and prepare a homogeneous solution at 40°C under a nitrogen atmosphere. Then, slowly dropwise add a mixture of 38.1 g of tetramethoxysilane, 30.6 g of methyltrimethoxysilane, and 5.9 g of 3-glycidoxypropyltrimethoxysilane to the homogeneous solution. After the dropwise addition, carry out a hydrolysis and condensation reaction at 40°C for 12 hours. After the reaction is completed, add 600 g of PGEE (propylene glycol ethyl ether), distill off the water and by-produced alcohol, and recover 440 g of a PGEE solution of the polysiloxane compound (C1) (compound concentration 10%). Measure the polystyrene-equivalent molecular weight of the polysiloxane compound (C1), and the result is Mw = 2900.

[0289] (Synthesis Example 2)

[0290] Synthesis of polysiloxane (C2) for silicon-containing antireflection film

[0291] [Chemical Formula 24]

[0292]

[0293] 1400 g of ethanol, 700 g of ultrapure water, and 50 g of 25% tetramethylammonium hydroxide were added and made into a homogeneous solution at 40°C under a nitrogen atmosphere. Then, a mixture of 138.6 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 37.2 g of phenyltrimethoxysilane was slowly added dropwise to the homogeneous solution, and the reaction was carried out at 40°C for 2 hours. After the reaction was completed, 35 g of acetic acid was added to stop the reaction, and ethanol was distilled off under reduced pressure. 2000 ml of ethyl acetate was added to the solution after distillation, the aqueous layer was separated, the organic layer was washed twice with 400 ml of ultrapure water, and then 1000 g of PGMEA (propylene glycol monomethyl ether acetate) was added, and water and low-boiling solvents were distilled off to recover 600 g of a PGMEA solution of polysiloxane compound (C2) (compound concentration 20%). The polystyrene-equivalent molecular weight of the polysiloxane compound (C2) was measured, and the result was Mw = 2800.

[0294] (Synthesis Example 3)

[0295] Synthesis of polysiloxane (C3) for silicon-containing antireflection film

[0296] [Chemical Formula 25]

[0297]

[0298] A mixture of 20.4 g of methyltrimethoxysilane, 45.7 g of tetramethoxysilane, and 20.1 g of the following compound (Formula C3-1) was added to a mixture of 120 g of methanol, 0.1 g of 10% nitric acid, and 60 g of deionized water, and the mixture was maintained at 40°C for 12 hours to carry out hydrolysis and condensation. After the reaction was completed, 500 g of propylene glycol ethyl ether (PGEE) was added, and the water for hydrolysis and condensation and the by-produced alcohol were distilled off under reduced pressure to obtain 450 g of a PGEE solution of polysiloxane compound (C3) (compound concentration 10%). The polystyrene-equivalent molecular weight of the polysiloxane compound (C3) was measured, and the result was Mw = 2,200.

[0299] [Chemical Formula 26]

[0300]

[0301] [Preparation of Composition for Forming Silicon-Containing Antireflection Film for Examples and Comparative Examples]

[0302] The compounds (C1) to (C3) obtained in the above synthesis examples, a crosslinking agent, a crosslinking catalyst, an acid generator, an acid (maleic acid), a solvent, and water were mixed in the proportions shown in Table 1, and filtered through a 0.1-μm fluororesin filter to prepare solutions of the silicon-containing antireflection film-forming composition, which were named UDL-1 to UDL-12 and Comparative Example UDL-1, respectively.

[0303] [Table 1]

[0304]

[0305] The crosslinking agents used are as follows.

[0306] [Chemical formula 27]

[0307]

[0308] The crosslinking catalysts used are as follows. TPSNO 3 ··· Triphenylsulfonium nitrate QBANO 3 ··· Tetrabutylammonium nitrate The solvents used are as follows.

[0309] PGEE ··· Propylene glycol ether

[0310] PGMEA ··· Propylene glycol methyl ether acetate

[0311] The acid generators PAG1 to PAG3 used are listed in Table 2 below, and the acid generator TAG1 is as follows.

[0312] [Table 2]

[0313]

[0314] [Chemical formula 28]

[0315]

[0316] [Preparation of the composition for forming the antireflection film for comparative example]

[0317] Comparative Example UDL-2 (Table 3) and Comparative Example UDL-3 (Table 4) were used as the compositions for forming the antireflection film for comparative example.

[0318] For Comparative Example UDL-2, the following polymer (P1), a thermal acid generator (TAG1), and a solvent were used in the composition described in Table 3.

[0319] [Chemical formula 29]

[0320]

[0321] [Chemical formula 30]

[0322]

[0323] [Table 3]

[0324]

[0325] Comparative Example UDL-3 used the above crosslinking agent (A1) and solvent in the composition described in Table 4.

[0326] [Table 4]

[0327]

[0328] [Example 1 and Comparative Example 1: Solvent Resistance Evaluation and Optical Constant Evaluation]

[0329] The above-prepared silicon-containing antireflection film-forming compositions (UDL-1 to 12, Comparative Example UDL-1) and the comparative antireflection film-forming compositions (Comparative Examples UDL2 and 3) were respectively coated on silicon substrates. After the coated films were fired at 220°C for 60 seconds to form antireflection films, the film thickness from the center to the outer periphery of the substrate was measured, and the average film thickness (a [nm]) was calculated. Then, PGMEA solvent was dropped thereon, left for 30 seconds and spun dry, and 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 obtained.

[0330] Also, the above-prepared silicon-containing antireflection film-forming compositions (UDL-1 to 12, Comparative Example UDL-1) and the comparative antireflection film-forming compositions (Comparative Examples UDL2 and 3) were respectively coated on silicon substrates. After the coated films were fired at 220°C for 60 seconds to form antireflection films, the optical constants (refractive index n, extinction coefficient k) of each antireflection film at a wavelength of 193 nm were obtained using a variable incident angle spectroscopic ellipsometer (VASE) manufactured by J.A. Wollam Company.

[0331] Also, the silicon content in the above-prepared silicon-containing antireflection film was determined using RBS (Rutherford backscattering analysis).

[0332] The results are shown in Table 5 below.

[0333] [Table 5]

[0334]

[0335] Examples 1-1 to 1-12 of the silicon-containing antireflection film used in the pattern formation method of the present invention had a residual film ratio ((b / a)×100) of 99% or more after PGMEA rinsing treatment, indicating that crosslinking reaction occurred and sufficient solvent resistance was exhibited. In Comparative Example 1-1 using Comparative Example UDL-1 without a crosslinking agent, the solvent resistance was less than 99% probably due to slightly insufficient thermosetting property. Also, in Comparative Example UDL-3 using Compound A1 which is a crosslinking agent of the silicon-containing antireflection film alone, the solvent resistance was 0% probably due to insufficient thermosetting property.

[0336] Also, the optical constants of Examples 1-1 to 1-12 of the silicon-containing antireflection film used in the pattern formation method of the present invention were all between an n value of 1.79 to 1.82 and a k value of 0.3 to 0.35. Regarding the optical constants, they also depend on factors such as film thickness and the type of laminated film, but generally, if the n value is between 1.75 to 2.05 and the k value is between 0.2 to 0.4, even when forming a metal-containing film with a thin film of 10 nm or less, the reflected light from the substrate during ArF immersion / high NA exposure can be suppressed to a considerable extent and can be used as an antireflection film for photoresist patterning ( Figure 3 ). In the above Examples 1-1 to 1-12, the optical constants were all within an ideal range, indicating that they are suitable as an underlayer film for a photoresist for photoresist patterning.

[0337] [Examples 2 and Comparative Examples 2: ArF Patterning Test]

[0338] On a silicon wafer on which a silicon oxide film with a film thickness of 200 nm had been formed, an amorphous carbon film (ACL, carbon content 73 atomic%) or a SOC film (ODL-306, carbon content 61 atomic%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed as an organic underlayer film with a film thickness of 35 nm. Then, on the organic underlayer film, a silicon oxynitride film (SiON) was formed as a silicon-containing hard mask with a film thickness of 15 nm. On top of this, a composition for forming an antireflection film (UDL-1 to 12, Comparative Examples UDL-1 to 2) was respectively coated on the above SiON film and heated at 220°C for 60 seconds to form an antireflection film with a film thickness of 10 nm.

[0339] Then, a negative-tone developing ArF resist solution (PR1) containing the following ArF resist polymer, acid generator, amine quencher, surfactant, and solvent as described in Table 6 was coated on the above silicon-containing antireflection film and baked at 110°C for 60 seconds to form an upper resist film (photoresist film) with a film thickness of 70 nm. Thus, a laminate was obtained.

[0340] [Chemical Formula 31]

[0341]

[0342] [Photoacid generator]

[0343] (PAG-A): Triphenylsulfonium 2-(adamantane-1-carbonyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonate (a compound described in JP-A-2007-145797)

[0344] [Amine quencher]

[0345] (Q-1): 2-Morpholinoethyl laurate

[0346] [Surfactant]

[0347] Base-soluble surfactant (F-1): Poly(3,3,3-trifluoro-2-hydroxy-1,1-dimethyl-2-trifluoromethylpropyl methacrylate / methacrylic acid = 1,1,1-trifluoro-2-hydroxy-6-methyl-2-trifluoromethylhept-4-yl methacrylate) (a compound described in JP-A-2008-122932)

[0348] Weight-average molecular weight (Mw) = 7,300, Dispersity (Mw / Mn) = 1.86

[0349] [Chemical formula 32]

[0350]

[0351] [Table 6]

[0352]

[0353] [Organic solvent]

[0354] PGMEA: Propylene glycol monomethyl ether acetate

[0355] CyHO: Cyclohexanone

[0356] For the photoresist film of the laminate obtained by the above method, using an ArF immersion excimer laser stepper (manufactured by ASML, XT1900i, NA1.35, σ0.98 / 0.80, crosspole aperture 30 degrees, 6% half-tone phase shift mask), exposure was performed using a mask arranged with hole patterns having a pitch of 90 nm and a width of 36 nm on the wafer. After exposure, a heat treatment (PEB) of 60 seconds was performed, and while rotating the development nozzle at 30 rpm, butyl acetate was sprayed for 3 seconds, and then, standing immersion development was performed for 27 seconds to obtain a negative resist pattern.

[0357] The pore size of the resist pattern formed under the above conditions was measured using an electron microscope (CG5000) manufactured by Hitachi High-Technologies Corporation. Also, the cross-sectional shape (pattern shape) was observed using an electron microscope (S-4800) manufactured by Hitachi High-Technologies Corporation. When no trailing shape or undercut shape was observed, it was rated as good, and when an obvious trailing shape or undercut shape was observed, it was rated as bad.

[0358] The reflectance was calculated using PROLITH 2020a (LITHO TECH JAPAN Corporation). The film thickness of the antireflection film was fixed at 10 nm, and the reflectance of the antireflection film with n ranging from 1.60 to 2.10 and k ranging from 0.20 to 0.40 was calculated. The results are as Figure 3 shown. It is preferable that the optical constant (n / k) of the reflected light from the substrate during pattern exposure can be reduced to 1.0% or less.

[0359] Using the above resist pattern (layer D) as a mask, the antireflection film (layer C) and the silicon-containing hard mask (layer B) were dry-etched under the following conditions (1), and then the pattern was transferred to the organic underlayer film (layer A) under the following conditions (2). Finally, the pattern was transferred to the oxide film (substrate to be processed) under the following conditions (3).

[0360] (1) Processing conditions for the antireflection film (layer C) and the silicon-containing hard mask (layer B)

[0361] Equipment: Dry etching equipment Telius SP manufactured by Tokyo Electron Limited

[0362] Etching conditions (1):

[0363] Chamber pressure: 80 mT

[0364] RF power (upper): 500 W

[0365] RF power (lower): 300 W

[0366] CF 4 Gas flow rate: 150 sccm

[0367] CHF 3 Gas flow rate: 50 sccm

[0368] Time: 15 sec

[0369] (2) Processing conditions for the organic underlayer film (layer A)

[0370] Chamber pressure: 80 mT

[0371] RF power (upper): 500 W

[0372] RF power (lower): 300 W

[0373] CO 2 Gas flow rate: 320 sccm

[0374] N 2 Gas flow rate: 80 sccm

[0375] Time: 45 sec

[0376] (3) Processing conditions of the oxide film (substrate to be processed)

[0377] Chamber pressure: 10 mT

[0378] RF power (upper part): 100 W

[0379] RF power (lower part): 800 W

[0380] CF 4 Gas flow rate: 25 sccm

[0381] CHF 3 Gas flow rate: 15 sccm

[0382] O 2 Gas flow rate: 5 sccm

[0383] Time: 60 sec

[0384] The pore size of the pattern fabricated under the above conditions was measured using a Hitachi High-Technologies Corporation electron microscope (CG5000). Also, the pore diameters at 50 different locations within the same exposure range were measured, and the 3σ value of the size deviation was obtained and defined as CDU. The results are shown in Table 7. The smaller the CDU value, the better the size controllability and thus the more ideal it is.

[0385] [Table 7]

[0386]

[0387]

[0388] From the results in Table 7, it can be seen that for the examples (Examples 2-1 to 2-13) of the pattern formation method of the present invention, the cross-sectional pattern shape after exposure is good, and the processed substrate shows good CDU after processing. In particular, Examples 2-1 to 2-12 using the ACL film for the organic underlayer film (A layer) show excellent CDU. It is speculated that compared with the spin-coated organic underlayer film (SOC film), the ACL film shows dry etching resistance to fluorine-based gases during the processing of the substrate to be processed, so excellent pattern transferability is shown.

[0389] In Comparative Example 2-1, the cross-sectional pattern shape after exposure was an undercut shape. It is speculated that since the silicon-containing antireflection film was not used, the alkaline components generated from the SiON film moved to the photoresist film, resulting in a decrease in the resolution of the resist. In addition, due to insufficient reflection light suppression effect, it is speculated that the CDU of the resist pattern deteriorated after exposure, and the CDU of the processed substrate after processing was also insufficient.

[0390] In Comparative Example 2-2, the cross-sectional pattern shape after exposure was an undercut shape. It is speculated that because the poisoning suppression effect of Comparative Example UDL-1 used as the silicon-containing antireflection was insufficient, the alkaline components generated from the SiON film moved to the photoresist film, resulting in a decrease in the resolution of the resist. From the above results, it can be said that in order to improve the denseness of the film, it is better to form the silicon-containing antireflection film used in the present invention using a composition containing polysiloxane and a crosslinking agent.

[0391] In Comparative Example 2-3, the cross-sectional pattern shape after exposure was an undercut shape. The reason is speculated to be insufficient poisoning suppression effect of the organic antireflection film (Comparative Example UDL-2) used as the antireflection film. In addition, due to insufficient reflection light suppression effect, it is speculated that the CDU of the resist pattern deteriorated after exposure, and the CDU of the processed substrate after processing was also insufficient.

[0392] From the above, it can be seen that the pattern formation method using the silicon-containing antireflection film of the present invention has a high adhesion with the resist pattern and an effect of suppressing the collapse of fine patterns, and also has excellent antireflection effect and an effect of suppressing the poisoning of the organic underlayer film to the photoresist film, and can give a resist upper layer film pattern shape with high rectangularity. Therefore, it is particularly suitable for multilayer resist processing and is extremely useful for fine patterning in the manufacture of semiconductor devices.

[0393] This specification includes the following aspects.

[0394] [1] A pattern formation method, characterized by comprising the following steps:

[0395] (1) On a substrate to be processed, sequentially stack (A) an organic underlayer film, (B) a silicon-containing hard mask, (C) a silicon-containing antireflection film, and (D) a photoresist film,

[0396] (2) Expose the pattern circuit region of the aforementioned (D) photoresist film to form an exposure pattern, and then develop the aforementioned exposure pattern with a developer to form a resist pattern on the aforementioned (D) photoresist film,

[0397] (3) Use the obtained aforementioned resist pattern as an etching mask to etch the aforementioned (C) silicon-containing antireflection film and the aforementioned (B) silicon-containing hard mask to form a hard mask intermediate film pattern,

[0398] (4) Using the obtained hard mask intermediate film pattern as an etching mask, etch the aforementioned (A) organic lower layer film to form an organic lower layer film pattern, and

[0399] (5) Using the obtained organic lower layer film pattern as an etching mask, etch the aforementioned substrate to be processed to form a pattern on the substrate to be processed.

[0400] The aforementioned (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film containing a polysiloxane containing any one or more of a repeating unit represented by the following general formula (Sx-1), a repeating unit represented by the following general formula (Sx-2), and a partial structure represented by the following general formula (Sx-3), and a crosslinking agent.

[0401] [Chemical formula 33]

[0402]

[0403] In the formula, R a , R b and R c are each independently a monovalent organic group having 1 to 30 carbon atoms, which may be the same or different.

[0404] [2] As in the pattern forming method of [1], form a layer selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxynitride film as the aforementioned (B) silicon-containing hard mask.

[0405] [3] As in the pattern forming method of [1] or [2], use the polysiloxane in which at least one of R a to R c in the aforementioned general formulas (Sx-1) to (Sx-3) is an organic group having one or more carbon-oxygen single bonds or carbon-oxygen double bonds to form the aforementioned (C) silicon-containing antireflection film.

[0406] [4] As in the pattern forming method of any one of [1] to [3], use a compound containing an isocyanuric acid structure as the aforementioned crosslinking agent to form the aforementioned (C) silicon-containing antireflection film.

[0407] [5] As in the pattern forming method of any one of [1] to [4], wherein the aforementioned (A) organic lower layer film is formed by CVD method.

[0408] [6] As in the pattern forming method of any one of [1] to [5], form a film containing any one of a graphene film, an amorphous carbon film, and a diamond-like carbon film as the aforementioned (A) organic lower layer film.

[0409] [7] The pattern forming method according to any one of [1] to [6], wherein the silicon-containing hard mask (B) and the silicon-containing anti-reflection film (C) are formed so that the film thickness FTb of the silicon-containing hard mask (B) and the film thickness FTc of the silicon-containing anti-reflection film (C) satisfy the relationship FTb > FTc.

[0410] [8] The pattern forming method according to any one of [1] to [7], wherein the silicon-containing anti-reflection film (C) is formed so that the film thickness of the silicon-containing anti-reflection film (C) is 15 nm or less.

[0411] Furthermore, the present invention is not limited to the above-described embodiments. The above-described embodiments are illustrative, and those having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effects are all included within the technical scope of the present invention.

[0412] Explanation of reference numerals

[0413] 1: Substrate

[0414] 2: Layer to be processed

[0415] 2a: Pattern (pattern formed on the layer to be processed)

[0416] 3: Organic underlayer film

[0417] 3a: Organic underlayer film pattern

[0418] 4: Silicon-containing hard mask film

[0419] 4a: Hard mask intermediate film pattern

[0420] 5: Silicon-containing anti-reflection film

[0421] 5a: Silicon-containing anti-reflection film pattern

[0422] 6: Photoresist film

[0423] 6a: Resist pattern

[0424] 7: Exposed portion

[0425] 10: Substrate to be processed

Claims

1. A pattern forming method, characterized in that The following steps are involved: (1) stacking (A) an organic lower layer film, (B) a silicon-containing hard mask film, (C) a silicon-containing antireflection film, and (D) a photoresist film in order on a substrate to be processed, (2) exposing the pattern circuit region of the (D) photoresist film to form an exposure pattern, and then developing the exposure pattern with a developer to form a resist pattern on the (D) photoresist film, (3) using the obtained resist pattern as an etching mask, etching the (C) silicon-containing antireflection film and the (B) silicon-containing hard mask film to form a hard mask intermediate film pattern, (4) using the obtained hard mask intermediate film pattern as an etching mask to etch the (A) organic underlayer film to form an organic underlayer film pattern, and (5) using the obtained organic lower film pattern as an etching mask to etch the substrate to form a pattern on the substrate to be processed, The silicon-containing antireflection film (C) is formed using a silicon-containing antireflection film-forming composition containing a polysiloxane containing at least one of a repeating unit represented by the following general formula (Sx-1), a repeating unit represented by the following general formula (Sx-2), and a partial structure represented by the following general formula (Sx-3), and a crosslinking agent. In the formula, R a , R b and R c They are monovalent organic groups having 1 to 30 carbon atoms, which may be the same or different.

2. The pattern forming method according to claim 1, wherein a layer selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxide nitride film is formed as the (B) silicon-containing hard mask film.

3. The pattern forming method according to claim 1, wherein R a ~R c The (C) silicon-containing antireflection film is formed by using the polysiloxane in which at least one of the organic groups is an organic group having one or more carbon-oxygen single bonds or carbon-oxygen double bonds. 4 . The pattern forming method according to claim 1 , wherein the (C) silicon-containing antireflection film is formed by using a compound containing an isocyanuric acid structure as the crosslinking agent.

5. The pattern forming method according to claim 1, wherein: The (A) organic underlayer film is formed by a CVD method. 6 . The pattern forming method according to claim 1 , wherein a film including any one of a graphene film, an amorphous carbon film and a diamond-like carbon film is formed as the (A) organic underlayer film.

7. The pattern forming method according to claim 1, wherein: The (B) silicon-containing hard mask and the (C) silicon-containing anti-reflection film are formed so that the film thickness FTb of the (B) silicon-containing hard mask and the film thickness FTc of the (C) silicon-containing anti-reflection film satisfy the relationship FTb>FTc.

8. The pattern forming method according to any one of claims 1 to 7, wherein: The (C) silicon-containing antireflection film is formed so that the film thickness of the (C) silicon-containing antireflection film is 15 nm or less.

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