Patterning process

Abstract

To provide a patterning process capable of forming a fine pattern without edge roughness.SOLUTION: A patterning process includes the steps of: stacking an organic underlayer film, a silicon-containing hard mask, a silicon-containing antireflective film and a photoresist film in this order on a substrate to be processed; forming a resist pattern in the photoresist film; forming a hard mask middle film pattern; forming an organic underlayer film pattern; and forming a pattern in the substrate to be processed. The silicon-containing antireflective film is formed using a silicon-containing antireflective film-forming composition containing a crosslinking agent and a polysiloxane containing any one or more of a repeating unit represented by the specified general formula (Sx-1), a repeating unit represented by the specified general formula (Sx-2), and a partial structure represented by the specified general formula (Sx-3).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for forming a pattern using a silicon-containing antireflection film.

Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern dimensions 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 a resist composition therefor. The core of this has been the positive photoresist composition used in a single layer. This single-layer positive photoresist composition has a skeleton in the resist resin that has etching resistance against dry etching with chlorine-based or fluorine-based gas plasmas, and has a switching mechanism such that the exposed portion dissolves, thereby dissolving the exposed portion to form a pattern and dry-etching the substrate to be processed using the remaining resist pattern as an etching mask.

[0003] However, when the film thickness of the photoresist film used is directly miniaturized, that is, when the pattern width is made smaller, the resolution performance of the photoresist film deteriorates, and when attempting to develop the photoresist film into a pattern with a developer, the so-called aspect ratio becomes too large, resulting in a problem that pattern collapse occurs. For this reason, the photoresist film has been thinned as the pattern is miniaturized.

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

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

[0006] As one method to solve such problems, there is a multilayer resist method. In this method, a resist intermediate film with different etching selectivity from the photoresist film (i.e., the resist upper layer film) is interposed between the resist upper layer film and the substrate to be processed. After obtaining a pattern (resist pattern) on the resist upper layer film, the resist intermediate film is dry-etched using the resist pattern as a dry etching mask to transfer the pattern (resist intermediate film pattern) to the resist intermediate film. Further, using the resist intermediate film pattern as a dry etching mask, the substrate to be processed is dry-etched to transfer the pattern to the substrate to be processed.

[0007] One of the multilayer resist methods is a three-layer resist method that can be performed using a general resist composition used in the single-layer resist method. In this three-layer resist method, for example, an organic film made of novolak resin or the like is formed as a resist lower layer film on a substrate to be processed, a silicon-containing resist intermediate film is formed as a resist intermediate film thereon, and a normal organic photoresist film is formed as a resist upper layer film thereon. When performing dry etching with a fluorine-based gas plasma, the organic resist upper layer film has a good etching selectivity with respect to the silicon-containing resist intermediate film, so the resist upper layer film pattern can be transferred to the silicon-containing resist intermediate film by dry etching with a 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 substrate processing, the resist upper layer film pattern can be transferred to the silicon-containing resist intermediate film (resist intermediate film), and then, if pattern transfer to the organic film by dry etching with an oxygen-based or hydrogen-based gas plasma is performed, a pattern of an organic film (resist lower layer film) made of novolak resin or the like that has sufficient dry etching resistance for substrate processing can be obtained. As the resist lower layer film as described above, many are already known, such as those described in Patent Document 1 for example.

[0008] As the silicon-containing resist intermediate film used in the three-layer resist method as described above, a silicon-containing inorganic film by CVD, such as a SiO 2 film (for example, Patent Document 2 etc.), a silicon-containing hard mask such as a SiON film (for example, Patent Document 3 etc.), and as those obtained by spin coating, a SOG (spin-on glass) film (for example, Patent Document 4, and Non-Patent Document 1 etc.), a crosslinkable silsesquioxane film (for example, Patent Document 5 etc.) etc. are used, and a polysilane film (for example, Patent Document 6 etc.) may also be used. In the advanced three-layer resist method, a SOG film is often used because it is easy to adjust the antireflection function.

[0009] There are several problems with the SOG film that has been conventionally used in such a three-layer resist method. For example, when attempting to form a resist pattern by photolithography, it is well known that the exposure light is reflected by the substrate and interferes with the incident light, causing the so-called standing wave problem. In order to obtain a fine pattern without edge roughness of the resist film under the state-of-the-art ArF immersion and high-NA exposure conditions, it is essential to have an antireflection function as an intermediate film. Furthermore, in the state-of-the-art semiconductor processes as described above, since the photoresist is becoming thinner and thinner, the intermediate film is also required to be thinned. In the next-generation exposure process, it is required to impart an antireflection effect with a film thickness of 30 nm or less to the intermediate film. In addition, the dry etching rate with respect to oxygen gas plasma, which is generally used when processing the resist underlayer film, is preferably smaller in order to increase the etching selectivity between the SOG film and the underlayer film. From the trend of thinning, improvement of dry etching resistance is required for the SOG film.

[0010] In the three-layer resist method, it is difficult to develop a SOG film having both an antireflection function and dry etching resistance in a high dimension. In order to improve the antireflection function, it is necessary to use polysiloxane having an organic group with a high refractive index. However, when the introduction rate of the organic group is increased, the silicon component in the film decreases, so the dry etching resistance to oxygen gas deteriorates. On the other hand, there is a four-layer resist method in which the functions of antireflection and dry etching resistance are imparted to two different films. In Patent Document 7, a four-layer resist method composed of an organic underlayer film, a silicon-containing hard mask, an organic antireflection film, and a photoresist has been reported.

[0011] The antireflection film requires functions such as a layer for preventing the interaction between the substrate to be processed and the photoresist, a layer having a function of preventing the adverse effect of the material used for the photoresist or the substance generated during exposure of the photoresist on the substrate, a layer having a function of preventing the diffusion of the substance generated from the substrate during heat baking to the upper photoresist, and a function as a barrier layer for reducing the poisoning of the photoresist layer by the semiconductor substrate dielectric layer. However, these functions are insufficient in the organic antireflection film, and further improvement is considered necessary.

[0012] In Patent Document 8, a four-layer resist method using a silicon-containing antireflection film has been reported. Although it has been reported to be effective in suppressing poisoning against an organic antireflection film, it is a technology corresponding to a 65 nm pattern rule, and further improvement is expected in advanced semiconductor manufacturing that requires a technology corresponding to a pattern rule of 15 nm or less.

[0013] For example, in microfabrication using an ArF excimer laser (wavelength 193 nm), an EUV excimer laser (wavelength 13 nm), etc., the wiring width becomes narrow, and thus pattern collapse of a photoresist (also simply referred to as a resist) occurs. Further, in order to prevent pattern collapse of the resist, the thickness of the resist layer has also been decreasing as the wiring width decreases. When such a thin-film resist is used, further improvement in the dry etching rate is required for the resist underlayer film as well. However, for an organic resist underlayer film (organic underlayer film) with respect to an organic resist, film loss of the organic resist film occurs due to a dry etching gas for the organic resist underlayer film (for example, a fluorine-based gas, an oxygen gas, etc.). On the other hand, when a silicon-containing resist intermediate film is used under the organic resist film, when dry etching the silicon-containing resist intermediate film with a fluorine-based gas using the resist pattern as an etching mask, film loss of the organic resist film (the resist film on which the resist pattern is formed) is small with the fluorine-based gas, and the resist pattern formed by the thin-film resist can be accurately transferred to the silicon-containing resist intermediate film. Further, if the organic underlayer film is dry-etched with an oxygen-based dry etching gas using the silicon-containing resist intermediate film pattern as an etching mask, film loss of the silicon-containing resist intermediate film is small, and the resist pattern can be accurately transferred to the organic underlayer film, and the semiconductor substrate can be processed with a fluorine-based gas by using the organic underlayer film to which the resist pattern has been transferred as an etching mask.

[0014] However, in the three-layer process of the organic lower layer film, the silicon-containing resist intermediate film, and the resist film on the semiconductor substrate shown above, there has been a problem that it is technically difficult to achieve both high refractive index and dry etching resistance of the silicon-containing resist intermediate film.

[0015] In addition, due to the thinning of the resist film for the purpose of preventing pattern collapse, the silicon-containing resist intermediate film is also required to be thinned. As a result, under the state-of-the-art ArF immersion and high-NA exposure conditions, in order to further improve the antireflection effect, it is necessary to increase the refractive index of the silicon-containing resist intermediate film. In order to form a silicon-containing resist intermediate film with a high refractive index, generally, a SOG material containing polysiloxane with an organic group having a high refractive index is used. However, since these have a high introduction rate of organic groups and the silicon component in the film decreases, the dry etching resistance to oxygen gas becomes insufficient. In order to accurately transfer a fine pattern without edge roughness onto the substrate to be processed, a silicon-containing resist intermediate film with excellent dry etching resistance is required.

[0016] Note that Patent Document 9 discloses several pattern formation methods. As an example, it describes forming an organic film on a workpiece, forming a silicon-containing resist lower layer film on the organic film, and forming a resist upper layer film on the silicon-containing resist lower layer film. As another example, it describes forming a hard mask mainly composed of carbon on a workpiece, forming a silicon-containing resist lower layer film on the hard mask, and forming a resist upper layer film on the silicon-containing resist lower layer film. However, these processes have insufficient antireflection effects under state-of-the-art ArF immersion and high-NA exposure conditions, and a new method capable of forming a fine pattern without edge roughness is considered necessary.

Prior Art Documents

Patent Documents

[0017]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Non-Patent Document

[0018]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0019] The present invention has been made to solve the above problems, and an object thereof is to provide a patterning method capable of forming a fine pattern without edge roughness.

Means for Solving the Problems

[0020] In order to solve the above problems, in the present invention, there is provided a patterning method, (1) A step of laminating (A) an organic underlayer film, (B) a silicon-containing hard mask, (C) a silicon-containing antireflection film, and (D) a photoresist film on a substrate to be processed in this order; (2) A step of exposing a 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 antireflective film and the (B) silicon-containing hard mask to form an intermediate hard mask film pattern; (4) Using the obtained intermediate hard mask film pattern as an etching mask, etching the (A) organic underlayer film to form an organic underlayer film pattern; (5) Using the obtained organic underlayer film pattern as an etching mask, etching the substrate to be processed to form a pattern on the substrate to be processed; comprising The (C) silicon-containing antireflective film is formed using a composition for forming a silicon-containing antireflective film comprising 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. A pattern forming method is provided. [Chemical formula] (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.)

[0021] With such a pattern forming method, due to the combination of the (B) silicon-containing hard mask and the (C) silicon-containing antireflective film, a high antireflective effect can be exhibited under ArF immersion and high NA exposure conditions, so that a fine pattern without edge roughness can be obtained. In addition, since the composition for forming a silicon-containing antireflective film contains a crosslinking agent, it can exhibit an excellent poisoning suppression effect compared to conventional antireflective films, and has good adhesion to the resist pattern, so it can also be effective in preventing the collapse of fine patterns. Therefore, the pattern forming method of the present invention can transfer the resist pattern shape onto the substrate to be processed with high precision.

[0022] Further, as the (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.

[0023] By using such a (B) silicon-containing hard mask, the resist pattern shape 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 function can be provided.

[0024] In the general formulas (Sx-1) to (Sx-3), it is preferable to form the (C) silicon-containing antireflection film using the 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.

[0025] By using such a (C) silicon-containing resist antireflection film, it becomes possible to further improve the adhesion to the resist pattern and more reliably prevent the collapse of the fine pattern.

[0026] It is preferable to form the (C) silicon-containing antireflection film using a compound containing an isocyanuric acid structure as the crosslinking agent.

[0027] By using such a (C) silicon-containing antireflection film, the denseness of the silicon-containing antireflection film is improved, the basic components that may be generated from the (C) silicon-containing hard mask are prevented from migrating to the (D) photoresist film, and the ability to suppress the poisoning that reduces the sensitivity and resolution of the resist can be further improved. Further, it becomes possible to further improve the adhesion to the resist pattern and more reliably prevent the collapse of the fine pattern. Furthermore, it becomes possible to improve the refractive index of the (C) silicon-containing antireflection film and impart a more excellent antireflection function.

[0028] It is preferable to form the (A) organic underlayer film by CVD method.

[0029] By forming the (A) organic underlayer film in this way, it is possible to transfer the resist pattern shape onto the substrate to be processed with higher accuracy than in the pattern formation method using a coating-type organic underlayer film.

[0030] As the (A) organic underlayer film, it is preferable to form one containing any of a graphene film, an amorphous carbon film, and a diamond-like carbon film.

[0031] By using such an (A) organic underlayer film, since it shows high resistance to the fluorine-based gas used when processing the substrate to be processed by dry etching, it is possible to transfer the resist pattern shape onto the substrate to be processed with higher accuracy.

[0032] It is preferable to form the (B) silicon-containing hard mask and the (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 FTb > FTc.

[0033] By using the (C) silicon-containing antireflection film having such a film thickness range, it becomes possible to transfer the resist pattern shape onto the (C) silicon-containing antireflection film at high speed, so that a pattern shape with smaller roughness can be transferred onto the substrate to be processed.

[0034] It is preferable to form the (C) silicon-containing antireflection film so that the film thickness of the (C) silicon-containing antireflection film becomes 15 nm or less.

[0035] By using the (C) silicon-containing antireflection film having such a film thickness range, it becomes possible to transfer the resist pattern shape onto the (C) silicon-containing antireflection film at high speed, so that a pattern shape with smaller roughness can be transferred onto the substrate to be processed.

Advantages of the Invention

[0036] As described above, according to the pattern formation method of the present invention, it is possible to obtain a fine pattern without edge roughness while suppressing poisoning.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0038] As described above, in the fine patterning process using ArF immersion and high-NA exposure conditions in the semiconductor device manufacturing process, there has been a demand for the development of a pattern formation method using a multilayer resist method that has an excellent antireflection function capable of forming a fine pattern without edge roughness and has a processing selectivity capable of transferring the resist pattern shape onto the substrate to be processed with high accuracy.

[0039] Also, as described above, in the three-layer process of the organic underlayer film, silicon-containing hard mask, and resist film on the semiconductor substrate, there has been a problem that it is technically difficult to achieve both a high refractive index and dry etching resistance of the silicon-containing hard mask.

[0040] In view of such problems, it was investigated whether the above problems could be solved by providing a silicon-containing antireflection film between the (B) silicon-containing hard mask and the (D) photoresist film. On the other hand, in the silicon-containing antireflection film as disclosed in Patent Document 8, there are problems in suppressing poisoning from the resist underlayer to the photoresist film, and intensive studies were repeatedly conducted on the silicon-containing antireflection film. As a result, it was found that a (C) silicon-containing antireflection film formed using 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 has both an excellent poisoning suppression effect and an antireflection effect, and thus it is possible to transfer a fine pattern without edge roughness while sufficiently suppressing poisoning.

[0041] Then, the present inventors found that the above problems can be solved by a pattern formation method including a step of laminating each layer in the order of (A) an organic underlayer film, (B) a silicon-containing hard mask, the above (C) silicon-containing antireflection film, and (D) a photoresist film on a semiconductor substrate, a step of exposing and developing the (D) photoresist film to form a resist pattern, and a step of processing each layer based on the resist pattern and finally transferring the resist pattern onto the substrate to be processed, thereby completing the present invention.

[0042] That is, the present invention is a pattern formation method, comprising: (1) a step of laminating, in this order, an (A) organic underlayer film, a (B) silicon-containing hard mask, a (C) silicon-containing antireflection film, and a (D) photoresist film on a substrate to be processed; (2) a step of exposing a 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 in the (D) photoresist film; (3) a step of using the obtained resist pattern as an etching mask to etch the (C) silicon-containing antireflection film and the (B) silicon-containing hard mask to form a hard mask intermediate film pattern; (4) Using the obtained hard mask intermediate film pattern as an etching mask, etching the (A) organic lower layer film to form an organic lower layer film pattern; (5) Using the obtained organic lower layer film pattern as an etching mask, etching the substrate to be processed to form a pattern on the substrate to be processed; comprising: The (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film comprising 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. A pattern forming method characterized by the above.

Chemical formula

[0043] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0044] <Pattern Forming Method> The present invention relates to a pattern forming method, (1) A step of laminating an (A) organic lower layer film, a (B) silicon-containing hard mask, a (C) silicon-containing antireflection film, and a (D) photoresist film on a substrate to be processed in this order; (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 to form a hard mask intermediate film pattern; (4) Using the obtained hard mask intermediate film pattern as an etching mask, etching the (A) organic lower layer film to form an organic lower layer film pattern; (5) Using the obtained organic lower layer film pattern as an etching mask, etching the substrate to be processed to form a pattern on the substrate to be processed; comprising: The (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film comprising 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. A pattern forming method characterized by the above. [Chemical formula] (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.)

[0045] In the above pattern forming method, by combining a (C) silicon-containing antireflection film excellent in antireflection function and a (B) silicon-containing hard mask excellent in dry etching resistance, even in a fine patterning process using ArF immersion and high NA exposure conditions in the semiconductor device manufacturing process, it is possible to transfer a resist pattern shape without edge roughness onto the substrate to be processed with high precision while sufficiently suppressing poisoning.

[0046] Hereinafter, each step of the pattern forming method of the present invention will be described in more detail.

[0047] [(1) Laminating step] This step (1) is a step of laminating an (A) organic lower layer 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 in this order. The pattern forming method of the present invention forms at least the above four layers.

[0048] <(A) Organic underlayer film (A layer)> (A) As the organic underlayer film material that can be used for the organic underlayer film (A layer), for example, those known as the underlayer film for the three-layer resist method or the two-layer resist method using a silicon resist composition can be exemplified. For example, the resins or compositions shown in JP-A-2012-1687, JP-A-2012-77295, JP-A-2004-264710, JP-A-2005-043471, JP-A-2005-250434, JP-A-2007-293294, JP-A-2008-65303, JP-A-2004-205685, JP-A-2007-171895, JP-A-2009-14816, JP-A-2007-199653, JP-A-2008-274250, JP-A-2010-122656, JP-A-2012-214720, JP-A-2014-29435, International Publication WO2012 / 077640, International Publication WO2010 / 147155, International Publication WO2012 / 077640, International Publication WO2010 / 147155, International Publication WO2012 / 176767, JP-A-2005-128509, JP-A-2006-259249, JP-A-2006-259482, JP-A-2006-293298, JP-A-2007-316282, JP-A-2012-145897, JP-A-2017-119671, JP-A-2019-44022, etc. can be exemplified.

[0049] The above (A) organic underlayer film can be formed on a substrate to be processed, for example, by using a composition solution containing the above organic underlayer film material and a spin coating method or the like. After forming the organic underlayer film by a spin coating method or the like, it is desirable to bake it to evaporate the organic solvent. The baking temperature is preferably in the range of 100 to 600 °C, and the baking time is preferably in the range of 10 to 300 seconds.

[0050] Instead of the coating method using the above spin coating method or the like, it is also possible to apply an organic hard mask formed by CVD method or ALD method as the organic underlayer film. In the pattern forming method of the present invention, it is preferable to form the organic underlayer film by CVD method.

[0051] By using an organic hard mask formed by CVD method for the organic underlayer film, it becomes possible to transfer the resist pattern shape to the substrate to be processed with higher accuracy. The organic hard mask formed by CVD method shows higher resistance to dry etching using fluorine-based gas than the organic underlayer film formed of a coating type organic underlayer film material, and thus is useful for forming fine patterns.

[0052] As the above organic underlayer film, it is preferable to form one containing any of graphene film, amorphous carbon film and diamond-like carbon film. Such a film can be formed, for example, by CVD method.

[0053] In the pattern forming method using the above organic underlayer film, since it shows higher resistance to fluorine-based gas used when processing the substrate to be processed by dry etching than the organic underlayer film formed using a coating type organic underlayer film material, it becomes possible to transfer the resist pattern shape to the substrate to be processed with higher accuracy.

[0054] The thickness of the above organic underlayer film is preferably 10 to 1,000 nm, more preferably 15 nm to 100 nm, and still more preferably 20 nm to 50 nm.

[0055] <(B) Silicon-containing hard mask (B layer)> As the silicon-containing hard mask material that can be used for forming (B) the silicon-containing hard mask (B layer) in the pattern forming method of the present invention, a polysiloxane-based resist intermediate film material can be exemplified. For example, those described in Japanese Patent No. 471603 can be mentioned.

[0056] In conventional silicon-containing hard mask materials, polysiloxanes having pendant groups such as phenyl groups or light-absorbing groups having silicon-silicon bonds to provide an antireflection effect and crosslinking with an acid or heat are preferably used. On the other hand, in the pattern formation method of the present invention, since reflection can be suppressed by providing an antireflection function to the silicon-containing antireflection film, the silicon-containing hard mask material can minimize organic groups that can deteriorate the dry etching resistance when dry etching the organic lower layer film with an oxygen-based gas and deteriorate the pattern shape, enabling high-precision processing of the substrate to be processed.

[0057] The above silicon-containing hard mask can be formed on a substrate to be processed by, for example, a spin coating method or the like using a composition solution containing the above silicon-containing hard mask material. After forming the silicon-containing hard mask by a spin coating method or the like, it is desirable to bake it to evaporate the organic solvent. The baking temperature is preferably in the range of 100 to 600°C, and the baking time is preferably in the range of 10 to 300 seconds.

[0058] Alternatively, instead of the spin coating method or the like, it is also possible to form (B) a silicon-containing hard mask (inorganic hard mask) by a CVD method or an ALD method. Specifically, as (B) the 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. For example, examples of the method for forming a silicon nitride film are described in JP-A-2002-334869 and WO 2004 / 066377.

[0059] In the pattern formation method of the present invention, it is preferable to apply an inorganic hard mask (a layer selected from a silicon oxide film, a silicon nitride film, and a silicon oxynitride film) formed by a CVD method as (B) the silicon-containing hard mask.

[0060] (B) If the pattern formation method is to form the inorganic hard mask as a silicon-containing hard mask by CVD method, since it shows high resistance to the oxygen-based gas used when processing the organic underlayer film by dry etching, it is possible to transfer the resist pattern shape to the substrate to be processed with high precision. Further, the pattern formation method of the present invention, when using the inorganic hard mask, exhibits excellent effects from the viewpoint of suppressing poisoning from the organic underlayer film and the substrate to be processed as the base to the photoresist layer, and thus is useful in forming fine patterns.

[0061] (B) It is preferable that the film thickness FTb of the silicon-containing hard mask is in the range of 5 to 200 nm, and more preferably in the range of 10 to 100 nm.

[0062] Also, as the (B) silicon-containing hard mask, a silicon oxynitride film (SiON) having a high effect as an antireflection film is most preferably used. Since the substrate temperature when forming the SiON film is 300 to 500 °C, the organic underlayer film needs to be able to withstand a temperature of 300 to 500 °C.

[0063] <(C) Silicon-containing antireflection film (C layer)> In the pattern formation method of the present invention, the (C) silicon-containing antireflection film (C layer) is formed using a composition for forming a silicon-containing antireflection film containing polysiloxane (Sx) and a crosslinking agent, which will be described in detail below.

[0064] (Polysiloxane (Sx)) Polysiloxane (Sx) contains 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). Such polysiloxane (Sx) can also be called a thermally crosslinkable polysiloxane.

[0065]

Chemical formula

[0066] The polysiloxane (Sx) can be produced, for example, by hydrolytic condensation of the following hydrolyzable monomer (Sm).

[0067] Specific examples of the hydrolyzable monomer (Sm) include 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, t-butyltrimethoxysilane, t-butyltriethoxysilane, t-butyltripropoxysilane, t-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-t-butyldimethoxysilane, di-t-butyldiethoxysilane, di-t-butyldipropoxysilane, di-t-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,Examples thereof include bis(bicycloheptenyl)diisopropoxysilane, bis(bicycloheptyl)dimethoxysilane, bis(bicycloheptyl)diethoxysilane, bis(bicycloheptyl)dipropoxysilane, bis(bicycloheptyl)diisopropoxysilane, diadamantyldimethoxysilane, diadamantyldiethoxysilane, diadamantyldipropoxysilane, diadamantyldiisopropoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldipropoxysilane, diphenyldiisopropoxysilane, trimethylmethoxysilane, trimethylethoxysilane, dimethylethylmethoxysilane, dimethylethylethoxysilane, dimethylphenylmethoxysilane, dimethylphenylethoxysilane, dimethylbenzylmethoxysilane, dimethylbenzylethoxysilane, dimethylphenethylmethoxysilane, and dimethylphenethylethoxysilane, etc.

[0068] Preferred hydrolyzable monomers (Sm) include 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, phenyltriethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, phenethyltrimethoxysilane, phenethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, dipropyldimethoxysilane, dibutyldimethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, trimethylmethoxysilane, dimethylethylmethoxysilane, dimethylphenylmethoxysilane, dimethylbenzylmethoxysilane, and dimethylphenethylmethoxysilane, etc.

[0069] As the hydrolyzable monomer (Sm), the above R corresponding to the compounds exemplified above a , R b , and R c Another example of the organic group represented by can include an organic group having one or more carbon-oxygen single bonds or carbon-oxygen double bonds. Specifically, it is an organic group having one or more groups selected from the group consisting of an ether bond, an ester bond, an alkoxy group, and a hydroxy group. Examples of this include those represented by the following general formula (Sm-R).

[0070] (P-Q1 -(S 1 ) v1 -Q 2 -) u -(T) v2 -Q 3 -(S 2 ) v3 -Q 4 - (Sm-R) (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 alkycarbonyloxy 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 the same as above, p is an integer from 0 to 3, q is an integer from 0 to 10 (provided that q = 0 indicates 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 are shown below. In T, the positions where Q 2 and Q 3 are bonded are not particularly limited, but can be appropriately selected considering factors such as reactivity due to steric factors and availability of commercially available reagents used in the reaction.)

[0071]

Chemical formula

[0072] Preferred examples of the organic group having one or more carbon-oxygen single bonds or carbon-oxygen double bonds in the general formula (Sm-R) include the following. In the following formulas, (Si) is described to indicate the bonding position to Si.

[0073]

Chem.

[0074]

Chem.

[0075] Also, as examples of the organic groups of R a , R b , and R c , organic groups containing a silicon-silicon bond can also be used. Specifically, the following can be mentioned.

[0076]

Chem.

[0077] Also, as examples of the organic groups of R a , R b and R c , organic groups having a protecting group decomposable by an acid can also be used. Specifically, the organic groups described in paragraphs

[0043] to

[0048] of JP-A No. 2013-167669 and the organic groups obtained from the silicon compounds described in paragraph

[0056] of JP-A No. 2013-224279 can be mentioned.

[0078] Furthermore, as examples of the organic groups of R a , R b , and R c , organic groups having a fluorine atom can also be used. Specifically, the organic groups obtained from the silicon compounds described in paragraphs

[0059] to

[0065] of JP-A No. 2012-53253 can be mentioned.

[0079] In the above hydrolyzable monomer (Sm), one, two, or three chlorine, bromine, iodine, acetoxy group, methoxy group, ethoxy group, propoxy group, or butoxy group, etc. are bonded as hydrolyzable groups to the silicon shown in the above partial structure (Si).

[0080] [Synthesis method of polysiloxane (Sx)] (Synthesis method 1: Acid catalyst) As the polysiloxane (Sx) used in the pattern forming method of the present invention, for example, it can be produced by subjecting one or a mixture of two or more hydrolyzable monomers (Sm) to hydrolysis and condensation in the presence of an acid catalyst.

[0081] The acid catalysts used at this time include organic acids such as formic acid, acetic acid, oxalic acid, maleic acid, methanesulfonic acid, benzenesulfonic acid, and toluenesulfonic acid, and inorganic acids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, perchloric acid, and phosphoric acid. The amount of the catalyst used can be 1×10 -6 ~10 moles per mole of the monomer, preferably 1×10 -5 ~5 moles, more preferably 1×10 -4 ~1 mole.

[0082] When obtaining the polysiloxane (Sx) by hydrolysis and condensation from these monomers, the amount of water can be, for example, 0.01 to 100 moles per mole of the hydrolyzable substituent bonded to the monomer, more preferably 0.05 to 50 moles, and still more preferably 0.1 to 30 moles. If it is 100 moles or less, the apparatus used for the reaction becomes smaller and more economical.

[0083] As an operation method, for example, the monomer can be added to the aqueous catalyst solution to initiate the hydrolysis and condensation reaction. At this time, an organic solvent may be added to the aqueous catalyst solution, or the monomer may be diluted with an organic solvent, or both may be done. The reaction temperature can be, for example, 0 to 100 °C, preferably 5 to 80 °C. A method of maintaining the temperature at 5 to 80 °C during the dropping of the monomer and then aging at 20 to 80 °C is preferable.

[0084] Examples of organic solvents that can be added to the catalyst aqueous solution or can dilute the monomer include 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, butanediol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butanediol 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, t-butyl propionate, propylene glycol mono t-butyl ether acetate, γ-butyrolactone, and mixtures thereof, etc. are preferred.

[0085] Among these solvents, preferred ones are water-soluble ones. For example, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, polyhydric alcohols such as ethylene glycol, propylene glycol, polyhydric alcohol condensate derivatives such as butanediol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, acetone, acetonitrile, tetrahydrofuran, etc. can be mentioned. Among these, particularly preferred are those having a boiling point of 100 °C or lower.

[0086] Incidentally, the amount of the organic solvent used can be, for example, 0 to 1,000 ml per mole of the monomer, and particularly preferably 0 to 500 ml. When the amount of the organic solvent used is reduced, the reaction vessel becomes smaller and it is economical.

[0087] 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 alkaline substance that can be used for neutralization is preferably 0.1 to 2 equivalents relative to the acid used in the catalyst. Any substance may be used as long as it shows alkalinity in water.

[0088] Subsequently, it is preferable to remove by-products such as alcohol produced by the hydrolysis condensation reaction from the reaction mixture by distillation under reduced pressure or the like. The temperature at which the reaction mixture is heated at this time depends on the types of the added organic solvent and the alcohol generated by the reaction, etc., but 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, but is preferably below atmospheric pressure, more preferably 80 kPa or less in absolute pressure, and still more preferably 50 kPa or less in absolute pressure. Although it is difficult to accurately know the amount of alcohol removed at this time, it is desirable that approximately 80 mass% or more of the generated alcohol or the like is removed.

[0089] Next, the acid catalyst used for hydrolysis condensation may be removed from the reaction mixture. As a method for removing the acid catalyst, water and a polysiloxane solution are mixed, and the polysiloxane is extracted with an organic solvent. The organic solvent used at this time is preferably one that can dissolve the polysiloxane and separates into 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, butanediol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol 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, t-butyl acetate, t-butyl propionate, propylene glycol mono-t-butyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, cyclopentyl methyl ether, and mixtures thereof, etc.

[0090] Furthermore, it is also possible to use a mixture of a water-soluble organic solvent and a water-insoluble organic solvent. For example, methanol-ethyl acetate mixture, ethanol-ethyl acetate mixture, 1-propanol-ethyl acetate mixture, 2-propanol-ethyl acetate mixture, butanediol monomethyl ether-ethyl acetate mixture, propylene glycol monomethyl ether-ethyl acetate mixture, ethylene glycol monomethyl ether-ethyl acetate mixture, butanediol monoethyl ether-ethyl acetate mixture, propylene glycol monoethyl ether-ethyl acetate mixture, ethylene glycol monoethyl ether-ethyl acetate mixture, butanediol monopropyl ether-ethyl acetate mixture, propylene glycol monopropyl ether-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-methyl isobutyl ketone mixture, ethylene glycol monomethyl ether-methyl isobutyl ketone mixture, propylene glycol monoethyl ether-methyl isobutyl ketone mixture, ethylene glycol monoethyl ether-methyl isobutyl ketone mixture, propylene glycol monopropyl ether-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-cyclopentyl methyl ether mixture, ethylene glycol monomethyl ether-cyclopentyl methyl ether mixture, propylene glycol monoethyl ether-cyclopentyl methyl ether mixture, ethylene glycol monoethyl ether-cyclopentyl methyl ether mixture, propylene glycol monopropyl ether-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 thereto.

[0091] In addition, the mixing ratio of the water-soluble organic solvent and the water-insoluble organic solvent is appropriately selected. For example, it can be 0.1 to 1,000 parts by mass of the water-soluble organic solvent with respect to 100 parts by mass of the water-insoluble organic solvent, preferably 1 to 500 parts by mass, and more preferably 2 to 100 parts by mass.

[0092] Subsequently, it may be washed with neutral water. As this water, what is usually called deionized water or ultrapure water may be used. The amount of this water is preferably 0.01 to 100 L, more preferably 0.05 to 50 L, and still more preferably 0.1 to 5 L with respect to 1 L of the thermally crosslinkable polysiloxane solution. For this washing method, both may be put in the same container, stirred, and then left standing to separate the aqueous layer. The number of washing times may be 1 or more, but since washing more than 10 times does not necessarily result in the effect of just washing, it is preferably about 1 to 5 times.

[0093] As other methods for removing the acid catalyst, methods using an ion exchange resin and methods of neutralizing with an epoxy compound such as ethylene oxide or propylene oxide and then removing can be mentioned. These methods can be appropriately selected according to the acid catalyst used in the reaction.

[0094] In the water washing operation at this time, a part of the thermally crosslinkable polysiloxane may escape into the aqueous layer, and in some cases, an effect equivalent to a fractionation operation may be obtained. Therefore, the number of water washing times and the amount of washing water may be appropriately selected in view of the catalyst removal effect and the fractionation effect.

[0095] In both the polysiloxane solution in which the acid catalyst remains and the polysiloxane solution from which the acid catalyst has been removed, the final solvent is added and solvent exchange is performed under reduced pressure to obtain a desired polysiloxane solution. The temperature of the solvent exchange at this time depends on the type of reaction solvent or extraction solvent to be removed, but 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 type of extraction solvent to be removed, the exhaust device, the condensation device, and the heating temperature, but is preferably below atmospheric pressure, more preferably 80 kPa or less in absolute pressure, and still more preferably 50 kPa or less in absolute pressure.

[0096] At this time, the thermally crosslinkable polysiloxane may become unstable due to the change of the solvent. This is caused by the compatibility between the final solvent and the polysiloxane. To prevent this, as a stabilizer, a monohydric or polyhydric alcohol having a cyclic ether described in paragraphs

[0181] to

[0182] of JP-A-2009-126940 as a substituent may be added. The amount to be added is, for example, 0 to 25 parts by mass, preferably 0 to 15 parts by mass, more preferably 0 to 5 parts by mass, based on 100 parts by mass of the thermally crosslinkable polysiloxane in the solution before solvent exchange. However, when adding, 0.5 part by mass or more is preferable. If necessary, a monohydric or polyhydric alcohol having a cyclic ether as a substituent may be added to the solution before solvent exchange, and the solvent exchange operation may be performed.

[0097] When polysiloxane is concentrated above a certain concentration, the condensation reaction may further proceed, and there is a risk of changing to a state where it is no longer soluble in an organic solvent. Therefore, it is preferable to keep it in a solution state with an appropriate concentration. Also, if it is too dilute, the amount of solvent becomes excessive, so it is economically preferable to keep it in a solution state with an appropriate concentration. The concentration at this time is preferably 0.1 to 20% by mass.

[0098] The preferred final solvent to be added to the thermally crosslinkable polysiloxane solution is an alcohol-based solvent. Particularly preferred are, for example, monoalkyl ether derivatives such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and butanediol. Specifically, butanediol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol monopropyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, diacetone alcohol, etc. can be mentioned.

[0099] If these solvents are the main components, it is also possible to add a non-alcohol-based solvent as an auxiliary solvent. Examples of this 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, t-butyl acetate, t-butyl propionate, propylene glycol mono-t-butyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, cyclopentyl methyl ether, etc.

[0100] As another reaction operation using an acid catalyst, water or a water-containing organic solvent may be added to a monomer or an organic solution of the monomer to initiate a hydrolysis reaction. At this time, the catalyst may be added to the monomer or the organic solution of the monomer, or may be added to water or the water-containing organic solvent. The reaction temperature can be, for example, 0 to 100°C, preferably 10 to 80°C. A method of heating to 10 to 50°C during the dropping of water and then raising the temperature to 20 to 80°C for aging is preferred.

[0101] When using an organic solvent, a water-soluble one is preferred, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, acetone, tetrahydrofuran, acetonitrile, butanediol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, butanediol monoethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, butanediol 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 polyhydric alcohol condensate derivatives such as propylene glycol monopropyl ether and mixtures thereof.

[0102] The amount of the organic solvent used can be, for example, 0 to 1,000 ml per mole of the monomer, and particularly preferably 0 to 500 ml. When the amount of the organic solvent used is smaller, the reaction vessel becomes smaller and it is more economical. The post-treatment of the obtained reaction mixture is the same as the above method for post-treatment to obtain polysiloxane.

[0103] (Synthesis Method 2: Alkali Catalyst) In addition, polysiloxane (Sx) can also be produced by performing hydrolysis and condensation of one or a mixture of two or more hydrolyzable monomers (Sm) in the presence of an alkali catalyst.

[0104] The alkali catalysts used at this time include 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, picoline, 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 can be, for example, 1×10 -6 mol to 10 mol per 1 mol of the silicon monomer, preferably 1×10 -5 mol to 5 mol, more preferably 1×10 -4 mol to 1 mol.

[0105] When obtaining the thermally crosslinkable polysiloxane by hydrolysis and condensation from the above monomers, it is preferable to add 0.1 to 50 mol of water per 1 mol of the hydrolyzable substituent bonded to the monomer. If it is 50 mol or less, the apparatus used for the reaction becomes smaller and more economical.

[0106] As an operation method, for example, the monomer is added to the aqueous catalyst solution to initiate the hydrolysis and condensation reaction. At this time, an organic solvent may be added to the aqueous catalyst solution, or the monomer may be diluted with an organic solvent, or both may be done. The reaction temperature can be, for example, 0 to 100°C, preferably 5 to 80°C. A method of maintaining the temperature at 5 to 80°C during the dropping of the monomer and then aging at 20 to 80°C is preferable.

[0107] As the organic solvent that can be added to the aqueous alkali catalyst solution or can dilute the monomer, those similar to the organic solvents exemplified as those that can be added to the aqueous acid catalyst solution are preferably used. Note that, in order to carry out the reaction economically, the amount of the organic solvent used is preferably 0 to 1,000 ml per 1 mol of the monomer.

[0108] Thereafter, if necessary, a neutralization reaction of the catalyst is carried out to obtain an aqueous reaction mixture solution. 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 alkaline substance used as the catalyst. Any substance may be used as long as it shows acidity in water.

[0109] Subsequently, it is preferable to remove by-products such as alcohol generated by the hydrolysis condensation reaction from the reaction mixture by means of reduced pressure removal or the like. At this time, the temperature at which the reaction mixture is heated depends on the types of the added organic solvent and the alcohol generated by the reaction, but 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, but is preferably below atmospheric pressure, more preferably 80 kPa or less in absolute pressure, and still more preferably 50 kPa or less in absolute pressure. Although it is difficult to accurately know the amount of alcohol removed at this time, it is desirable that approximately 80 mass% or more of the generated alcohol is removed.

[0110] Next, in order to remove the alkali catalyst used in the hydrolysis condensation, the polysiloxane is extracted with an organic solvent. As the organic solvent to be used at this time, those that can dissolve the polysiloxane and separate into two layers when mixed with water are preferred. 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 amyl ketone, 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, t-butyl acetate, t-butyl propionate, propylene glycol mono-t-butyl ether acetate, γ-butyrolactone, methyl isobutyl ketone, cyclopentyl methyl ether, and mixtures thereof.

[0111] Furthermore, it is also possible to use a mixture of a water-soluble organic solvent and a water-insoluble organic solvent.

[0112] Specific examples of the organic solvent used when removing the alkali catalyst can be the above-mentioned organic solvents specifically exemplified as those used when removing the acid catalyst, and the same ones as the mixture of the water-soluble organic solvent and the water-insoluble organic solvent can be used.

[0113] Note that the mixing ratio of the water-soluble organic solvent and the water-insoluble organic solvent is appropriately selected. For example, it can be 0.1 to 1,000 parts by mass of the water-soluble organic solvent with respect to 100 parts by mass of the water-insoluble organic solvent, preferably 1 to 500 parts by mass, and more preferably 2 to 100 parts by mass.

[0114] Subsequently, wash with neutral water. As this water, what is usually called deionized water or ultrapure water may be used. The amount of this water is, for example, 0.01 to 100 L, preferably 0.05 to 50 L, more preferably 0.1 to 5 L with respect to 1 L of the thermally crosslinkable polysiloxane solution. As for the method of this washing, both may be put in the same container, stirred, and then left to stand to separate the aqueous layer. The number of washing times may be one or more, but even if washed 10 times or more, the effect of just washing is not always obtained, so preferably it is about 1 to 5 times.

[0115] Add the final solvent to the washed polysiloxane solution and perform solvent exchange under reduced pressure to obtain the desired polysiloxane solution. The temperature of the solvent exchange at this time depends on the type of extraction solvent to be removed, but is preferably 0 to 100 °C, more preferably 10 to 90 °C, still 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, but is preferably below atmospheric pressure, more preferably 80 kPa or less in absolute pressure, still more preferably 50 kPa or less in absolute pressure.

[0116] A preferable final solvent to be added to the polysiloxane solution is an alcohol-based solvent, and particularly preferable ones are monoalkyl ethers such as ethylene glycol, diethylene glycol, and triethylene glycol, and monoalkyl ethers such as propylene glycol and dipropylene glycol. Specifically, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, diacetone alcohol, etc. are preferable.

[0117] As another reaction operation using an alkali catalyst, for example, water or a water-containing organic solvent is added to a monomer or an organic solution of the monomer to initiate a hydrolysis reaction. At this time, the catalyst may be added to the monomer or the organic solution of the monomer, or may be added to the water or the water-containing organic solvent. The reaction temperature can be, 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.

[0118] The organic solvent that can be used as the organic solution of the monomer or the water-containing organic solvent is preferably water-soluble. For example, 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, and other polyhydric alcohol condensate derivatives and mixtures thereof can be mentioned.

[0119] The molecular weight of the polysiloxane obtained by the above synthesis method 1 or 2 can be adjusted by controlling the reaction conditions during polymerization as well as by the selection of the monomer. However, the weight average molecular weight is preferably 100,000 or less, more preferably 200 to 50,000, and still more preferably 300 to 30,000. If the weight average molecular weight is 100,000 or less, the generation of foreign substances and coating spots will not occur. The data regarding the above weight average molecular weight is represented by the molecular weight in terms of polystyrene using gel permeation chromatography (GPC) with RI as the detector and tetrahydrofuran as the elution solvent, using polystyrene as the standard substance.

[0120] The physical properties of the thermosetting polysiloxane used in the present invention vary depending on the type of acid or alkali catalyst used during hydrolysis and condensation and the reaction conditions. Therefore, it can be appropriately selected according to the performance of the target resist underlayer film.

[0121] Furthermore, a polysiloxane derivative produced from a mixture of one or more hydrolyzable monomers (Sm) and a hydrolyzable metal compound represented by the following general formula (Mm) under conditions using the above-mentioned acid or alkali catalyst can be used as a component of the resist underlayer film-forming composition.

Chemical formula

[0122] Examples of the hydrolyzable metal compound represented by the above general formula (Mm) include certain metal alkoxides such as boron, aluminum, gallium, yttrium, germanium, titanium, hafnium, etc. Specifically, those described in

[0107] to

[0123] of JP-A No. 2020-118960 can be used.

[0123] (Crosslinking agent) In the silicon-containing antireflection film-forming composition used in the pattern formation method of the present invention, a crosslinking agent is added to enhance the denseness of the antireflection film and prevent the base component that may be generated from the silicon-containing hard mask from migrating to the photoresist film and reducing the sensitivity and resolution of the resist, thereby improving the poisoning suppression effect.

[0124] The crosslinking agent is not particularly limited, and various known types of crosslinking agents can be widely used. Examples include melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, and phenol-based crosslinking agents. The above crosslinking agents can be used alone or in combination of two or more. When adding the crosslinking agent, the addition amount is preferably 5 to 50 parts, more preferably 10 to 40 parts, and still more preferably 10 to 30 parts with respect to 100 parts of the above silicon-containing antireflection film-forming composition. If the addition amount is 5 parts or more, sufficient curability can 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 low ratio of (A) silicon in the composition.

[0125] It is preferable that the above crosslinking agent is a compound containing an isocyanuric acid structure, and more preferably has the structure of the following formula (A-1).

[0126]

Chemical formula

[0127]

Chemical formula

[0128] When the crosslinking agent is a compound containing the above structure, when added to the composition for forming a silicon-containing antireflection film, it can form a dense film by crosslinking with polysiloxane by baking. Therefore, it is possible to form a silicon-containing antireflection film (C) that exhibits an excellent poisoning suppression effect. In addition, it is possible to further improve the adhesion to the photoresist film (resist upper layer film), and it has a higher effect of suppressing the collapse of ultra-fine patterns, and a resist pattern with a better pattern shape can be formed.

[0129] Specifically, the following structure can be exemplified as a preferable structure. R 3 is the same as above.

[0130]

Chemical formula

[0131]

Chemical formula

[0132]

Chemical formula

[0133]

Chemical formula

[0134]

Chemical formula

[0135] Examples of the structure represented by the above general formula (A-2) include the following.

[0136]

Chemical formula

[0137]

Chemical formula

[0138] Preferred examples of the compound represented by the above general formula (A-1) include the following. Specifically, R 1 is preferably an allyl group or a propargyl group, and R 2 is preferably a hydrogen atom, an acetyl group, or an acrylic group, and R 3 is preferably an allyl group or a group represented by the above general formula (A-2), and R 1 is more preferably an allyl group or a propargyl group, and R 2 is more preferably a hydrogen atom or an acetyl group, and R 3 is more preferably an allyl group.

[0139] [Chemical formula]

[0140] [Chemical formula]

[0141] (Acid generator) One or more acid generators may be further added to the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention. 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 may be used. However, in the present invention, it is more preferable that the acid generator to be added is a sulfonium salt and is a photoacid generator that generates an acid by the action of high-energy rays. Specifically, the materials described in paragraphs

[0061] to

[0085] of JP-A No. 2007-199653 can be added, but are not limited thereto.

[0142] The above acid generators can be used alone or in combination of two or more. When adding an acid generator, the addition amount is preferably 0.05 to 50 parts, more preferably 0.1 to 10 parts, per 100 parts of the thermally crosslinkable polysiloxane.

[0143] 〔Other components〕 (Crosslinking catalyst) In the present invention, a crosslinking catalyst (Xc) may 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). L a H b A (Xc0) (In the formula, L is lithium, sodium, potassium, rubidium, cesium, sulfonium, iodonium, phosphonium or ammonium. A is a non-nucleophilic counter ion. 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 counter ion.)

[0144] Specific crosslinking catalysts that can be used in the present invention as (Xc0) include, for example, sulfonium salts of the following general formula (Xc-1), iodonium salts of the following general formula (Xc-2), phosphonium salts of the following general formula (Xc-3), ammonium salts of the following general formula (Xc-4), alkali metal salts, etc., and polysiloxanes (Xc-10) having a sulfonium salt, iodonium salt, phosphonium salt, or iodonium salt as part of the structure. Specifically, materials described in paragraphs

[0124] to

[0163] of JP-A No. 2020-118960 can be added.

[0145]

Chemical formula

[0146]

Chemical formula

[0147] (In the above formula, R 204 、R 205 、R 206 、and R 207each represents a linear, branched or cyclic alkyl group, alkenyl group, oxoalkyl group or oxoalkenyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or an aralkyl group or aryloxoalkyl group having 7 to 12 carbon atoms, and some or all of the hydrogen atoms of these groups may be substituted with an alkoxy group or the like. Further, R 205 and R 206 may form a ring, and when forming a ring, R 205 and R 206 each represent an alkylene group having 1 to 6 carbon atoms. A - represents a non-nucleophilic counter ion. R 208 , R 209 , R 210 , and R 211 are the same as R 204 , R 205 , R 206 , and R 207 , but may be a hydrogen atom. R 208 and R 209 , or R 208 , R 209 and R 210 may form a ring, and 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.)

[0148] 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).

[0149] The composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention may further contain the following raw materials.

[0150] (organic acid) 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. Examples of the acid to be added at this time include formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic 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. Further, in order to maintain stability, two or more kinds of acids may be mixed and used.

[0151] 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, more preferably 0.1 to 5 parts by mass, based on 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.

[0152] Alternatively, when the above organic acid is converted to the pH of the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention, it is preferably formulated so that 0 ≦ pH ≦ 7, more preferably 0.3 ≦ pH ≦ 6.5, and still more preferably 0.5 ≦ pH ≦ 6.

[0153] (Water) In the present invention, water may be added to the composition for forming a silicon-containing antireflection film. When 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 is hydrated, so that the lithography performance is improved. The water content in the solvent component of the composition for forming a silicon-containing antireflection film used in the pattern forming method of the present invention is preferably more than 0% by mass and less than 50% by mass, particularly preferably 0.3 to 30% by mass, and still more preferably 0.5 to 20% by mass. If the added amount of water is within the above range, the uniformity of the silicon-containing antireflection film is good, there is no fear of repelling, and there is no fear of deterioration of lithography performance.

[0154] The amount of the total solvent containing water can be, for example, 100 to 100,000 parts by mass with respect to 100 parts by mass of the polysiloxane (Sx) which is the base polymer, and particularly 200 to 50,000 parts by mass is suitable.

[0155] (Stabilizer) Furthermore, in the present invention, a stabilizer can be added to the composition for forming a silicon-containing antireflection film. As the stabilizer, for example, a monohydric or polyhydric alcohol having a cyclic ether as a substituent can be added. In particular, adding the stabilizer described in paragraphs

[0181] to

[0182] of JP-A-2009-126940 can improve the stability of the composition for forming a silicon-containing antireflection film.

[0156] The added amount of the stabilizer can be, for example, 0.001 to 50 parts by mass with respect to 100 parts by mass of the polysiloxane (Sx) which is the base polymer, and particularly 0.01 to 40 parts by mass is suitable.

[0157] (Surfactant) Furthermore, in the present invention, a surfactant can be blended into the composition for forming a silicon-containing antireflection film as necessary. Specifically, the materials described in paragraph

[0185] of JP-A-2009-126940 can be added.

[0158] The addition amount of the surfactant can be, for example, 0.001 to 5 parts by mass, particularly preferably 0.01 to 1 part by mass, based on 100 parts by mass of the polysiloxane (Sx) which is the base polymer.

[0159] (High-boiling solvent) Furthermore, in the present invention, it is also possible to add a high-boiling solvent having a boiling point of 180°C or higher to the composition for forming a silicon-containing antireflection film, if necessary. Examples of such high-boiling solvents include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, gamma-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 mono-n-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.

[0160] 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, based on 100 parts by mass of the polysiloxane (Sx) which is the base polymer.

[0161] The above-mentioned (C) silicon-containing antireflection film can be formed, for example, on the (B) silicon-containing hard mask by a spin coating method or the like using the composition for forming the silicon-containing antireflection film. After forming the (C) silicon-containing antireflection film by a spin coating method or the like, it is desirable to bake 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.

[0162] The thickness FTc of the (C) silicon-containing antireflection film (C layer) is preferably thinner (FTb > FTc) than the film thickness FTb of the (B) silicon-containing hard mask (B layer). As a specific film thickness, 1 to 15 nm is preferable, 1 to 12 nm is more preferable, and 1 to 10 nm is even more preferable. That is, it is preferable 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.

[0163] If the silicon-containing antireflection film is within the above film thickness range, when processing the (C) silicon-containing antireflection film by dry etching using a fluorine-based gas with the resist pattern formed on the (D) photoresist film as a mask, it is possible to minimize the film overhang of the resist pattern. Therefore, in the next step, when processing the (B) silicon-containing hard mask by dry etching using a fluorine-based gas with the pattern including the (D) photoresist film and the (C) silicon-containing antireflection film as a mask, it becomes possible to transfer the resist pattern to the (B) silicon-containing hard mask with high precision.

[0164] The ratio (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 ratio (b) of silicon in the (C) silicon-containing antireflection film is 5% by mass or more, a high-refractive-index film can be formed, and the antireflection function can be improved. If the ratio (b) of silicon in the (C) silicon-containing antireflection film is 30% by mass or less, the acceleration of the etching rate with respect to the fluorine-based gas can be suppressed, and the selectivity ratio with the (B) silicon-containing hard mask (B layer) can be improved.

[0165] In the manufacturing method as described above, since 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), it becomes possible to transfer the resist pattern shape to the (B) silicon-containing hard mask (B layer) with high precision.

[0166] <(D) photoresist film (D layer)> In the pattern formation method of the present invention, the composition for a photoresist film used for forming a photoresist film is not particularly limited, but it is preferably composed of a chemically amplified photoresist composition. In the present invention, since either positive development using an alkaline developer or negative development using an organic solvent developer can be adopted, a positive-type photoresist film material or a negative-type photoresist film material may be appropriately selected according to the development method.

[0167] The thickness of the (D) photoresist film is not particularly limited, but is preferably 10 to 500 nm, particularly preferably 20 to 200 nm.

[0168] Also, the composition for a photoresist film may contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, and Zn. When forming a photoresist film with 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 by CVD or ALD.

[0169] When forming the (D) photoresist film by a deposition process such as CVD or ALD, the composition for the photoresist film is an EUV-sensitive metal oxide film, and the metal is selected from Sn, Zr, Hf, Ti, Bi, Sb, etc., and among them, Sn which is excellent in EUV sensitivity is preferable. The metal oxide-containing film may be a photosensitive organometallic oxide film such as an organotin oxide (for example, haloalkyl Sn, alkoxyalkyl Sn, or amidoalkyl Sn). Some specific examples of suitable precursors include trimethyltin chloride, dimethyltin dichloride, methyltin trichloride, tris(dimethylamino)methyltin(IV), and (dimethylamino)trimethyltin(IV).

[0170] The metal oxide film may be deposited, for example, by PECVD or PEALD using a Lam Vector (registered trademark) tool. In the ALD example, the Sn oxide precursor is separated from the O precursor / plasma. The deposition temperature preferably ranges from 50°C to 600°C. The deposition pressure preferably ranges between 100 and 6000 mTorr. The flow rate of the precursor liquid of the metal oxide-containing film (for example, an organotin oxide precursor) may be 0.01 to 10 cmm, and the gas flow rate (CO 2 , CO, Ar, N 2 etc.) may be 100 to 10000 sccm. The plasma power may be 200 to 1000 W per 300 mm wafer station using a high-frequency plasma (for example, 13.56 MHz, 27.1 MHz, or a higher frequency). The deposition thickness is preferably 100 to 2000 Å.

[0171] [(2) Step of forming a resist pattern] In this step, the pattern circuit region of the (D) photoresist film is exposed to form an exposure pattern, and then the exposure pattern is developed with a developer to form a resist pattern on the (D) photoresist film.

[0172] In the positive pattern formation method, after forming a (D) photoresist film and performing heat treatment, exposure is carried out, and then alkali development is performed using a normal alkali developer to obtain a positive resist pattern. It is also preferable to perform post-exposure baking (PEB) after exposure.

[0173] As the alkali developer, an aqueous solution of tetramethylammonium hydroxide (TMAH) or the like can be used.

[0174] In the negative pattern formation method, after forming a (D) photoresist and performing heat treatment, exposure is carried out, and then organic solvent development is usually performed using an organic solvent to obtain a negative resist pattern. It is also preferable to perform PEB after exposure.

[0175] As the developer for the organic solvent, a developer containing at least one 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, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate can be used.

[0176] Examples of the exposure light include high-energy rays having a wavelength of 300 nm or less, specifically, excimer lasers of 248 nm, 193 nm, and 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays, and the like.

[0177] As the method for forming the pattern of the resist upper layer film, it is preferable to form a pattern by photolithography with a wavelength of 5 nm or more and 300 nm or less, direct drawing by an electron beam, nanoimprinting, or a combination thereof.

[0178] [(3) Step of forming a hard mask intermediate film pattern] 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 hard mask intermediate film pattern.

[0179] In this step, for example, the resist pattern can be used as an etching mask to process the (C) silicon-containing antireflection film (C layer) and the (B) hard mask (B layer) by dry etching using a fluorine-based gas.

[0180] [(4) Step of forming an organic lower layer film pattern] In this step, the obtained hard mask intermediate film pattern is used as an etching mask to etch the (A) organic lower layer film to form an organic lower layer film pattern.

[0181] In this step, for example, the hard mask pattern can be used as an etching mask to process the (A) organic lower layer film (A layer) by dry etching using an oxygen-based gas.

[0182] [(5) Step of forming a pattern on a substrate to be processed] In this step, the obtained organic lower layer film pattern is used as an etching mask to etch the substrate to be processed to form a pattern on the substrate to be processed.

[0183] In this step, for example, the organic lower layer film pattern can be used as an etching mask to process the substrate to be processed by dry etching using a fluorine-based gas.

[0184] In the present invention, the workpiece (workpiece substrate) 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 are used. As the processed layer, various Low-k films such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si and their stopper films are used, and can usually be formed with a thickness of 30 to 10,000 nm, particularly 50 to 5,000 nm. When forming the processed layer, the substrate and the processed layer are made of different materials.

[0185] Here, with reference to FIG. 1, an example of a pattern formation method by the above three-layer resist process will be described. In this example, first, as shown in FIG. 1(A), an organic lower layer film 3 is formed on the processed layer 2 of the processed substrate 10 composed of the substrate 1 and the processed layer 2 thereon using an organic lower layer film material. Next, a silicon-containing hard mask 4 is formed on the organic lower layer 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. Subsequently, as shown in FIG. 1(B), the exposed portion 7 of the photoresist film 6 is pattern-exposed. Next, as shown in FIG. 1(C), it is developed with a developer to form a resist pattern 6a on the resist upper layer film. Next, as shown in FIG. 1(D), using the resist pattern 6a as a mask, the pattern is transferred to the silicon-containing antireflection film 5 and the silicon-containing hard mask 4 by dry etching to obtain an antireflection film pattern 5a and a hard mask intermediate film pattern 4a. Next, as shown in FIG. 1(E), using the hard mask intermediate film pattern 4a as a mask, the pattern is transferred to the organic lower layer film 3 by dry etching to obtain an organic lower layer film pattern 3a. Then, as shown in FIG. 1(F), using the organic lower layer film pattern 3a as a mask, the processed layer 2 on the substrate 1 is processed to form a pattern 2a on the processed substrate 10.

[0186] Further, FIG. 2 shows an example of a pattern formation method by a three-layer resist process for a comparative example. The pattern formation method of the example shown in FIG. 2 is significantly different from the pattern formation method of the example in FIG. 1 in that a silicon-containing antireflection film is not formed. In the three-layer process as shown in FIG. 2, there is a problem that it is technically difficult to achieve both high refractive index and dry etching resistance of the silicon-containing hard mask.

Example

[0187] Hereinafter, synthesis examples, examples, and comparative examples will be shown to more specifically explain the present invention, but the present invention is not limited thereto.

[0188] [Synthesis Example] Synthesis of Thermally Crosslinkable Polysiloxanes (C1) to (C3)

[0189] (Synthesis Example 1) Synthesis of Polysiloxane (C1) for Silicon-Containing Antireflection Film

Chemical formula

[0190] 120 g of methanol, 0.1 g of 10% nitric acid, and 60 g of ultrapure water were added and made into a homogeneous solution at 40°C under a nitrogen atmosphere. Then, a mixture of 38.1 g of tetramethoxysilane, 30.6 g of methyltrimethoxysilane, and 5.9 g of 3-glycidoxypropyltrimethoxysilane was slowly dropped into the homogeneous solution. After the dropping, a hydrolysis condensation reaction was carried out at 40°C for 12 hours. After the reaction was completed, 600 g of PGEE (propylene glycol ethyl ether) was added, and water and by-produced alcohol were distilled off, and 440 g of a PGEE solution of polysiloxane compound (C1) (compound concentration 10%) was recovered. When the polystyrene-equivalent molecular weight of polysiloxane compound (C1) was measured, Mw = 2900.

[0191] (Synthesis Example 2) Synthesis of Polysiloxane (C2) for Silicon-Containing Antireflection Film

Chemical formula

[0192] 1400 g of ethanol, 700 g of ultrapure water, and 50 g of 25% tetramethylammonium hydroxide were added, and a homogeneous solution was obtained 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 completion of the reaction, 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, 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%). When the polystyrene-reduced molecular weight of polysiloxane compound (C2) was measured, Mw = 2800.

[0193] (Synthesis Example 3) Synthesis of Polysiloxane (C3) for Silicon-Containing Antireflection Film

Chemical formula

[0194] To a mixture of 120 g of methanol, 0.1 g of 10% nitric acid, and 60 g of deionized water, 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, and the mixture was maintained at 40°C for 12 hours for hydrolysis and condensation. After completion of the reaction, 500 g of propylene glycol ethyl ether (PGEE) was added, and water and by-product alcohol used for hydrolysis and condensation were distilled off under reduced pressure to obtain 450 g of a PGEE solution of polysiloxane compound 1 (compound concentration 10%). When the polystyrene-reduced molecular weight of polysiloxane compound (C3) was measured, Mw = 2,200.

Chemical formula

[0195] [Preparation of Silicon-Containing Anti-Reflection Film Forming Compositions for Examples and Comparative Examples] The compounds (C1) to (C3) obtained in the above synthesis example, a crosslinking agent, a crosslinking catalyst, an acid generator, an acid (maleic acid), a solvent, and water were mixed at the ratios shown in Table 1 and filtered through a 0.1 μm fluororesin filter to prepare solutions of silicon-containing anti-reflection film forming compositions, designated as UDL-1 to UDL-12 and Comparative Example UDL-1, respectively.

[0196] [Table 1]

[0197] The crosslinking agent used is as follows.

[0198] [Chemical formula]

[0199] The crosslinking catalyst used is as follows. TPSNO 3 ... Triphenylsulfonium nitrate QBANO 3 ... Tetrabutylammonium nitrate

[0200] The solvent used is as follows. PGEE... Propylene glycol ethyl ether PGMEA... Propylene glycol methyl ether acetate

[0201] The acid generators PAG1 to PAG3 used are as shown in Table 2 below, and the acid generator TAG1 is as follows.

[0202] [Table 2]

[0203] [Chemical formula]

[0204] [Preparation of Composition for Forming Anti-Reflection Film for Comparative Example] As the composition for forming the anti-reflection film for the comparative example, Comparative Example UDL-2 (Table 3) and Comparative Example UDL-3 (Table 4) were used.

[0205] For Comparative Example UDL-2, a composition containing the following polymer (P1), a thermal acid generator (TAG1), and a solvent in the composition described in Table 3 was used.

[0206] [Chemical Formula]

[0207] [Chemical Formula]

[0208] [Table 3]

[0209] For Comparative Example UDL-3, a composition containing the above cross-linking agent (A1) and a solvent in the composition described in Table 4 was used.

[0210] [Table 4]

[0211] [Example 1 and Comparative Example 1: Solvent Resistance Evaluation and Optical Constant Evaluation] Each of the silicon-containing antireflection film-forming compositions (UDL-1 to 12, Comparative Example UDL-1) prepared above and the antireflection film-forming compositions for comparative examples (Comparative Examples UDL2 and 3) was applied onto a silicon substrate. After the coating film was baked at 220 °C for 60 seconds to form an antireflection film, the film thickness from the center part to the outer peripheral part of the substrate was measured to calculate the average film thickness (a [nm]). Subsequently, PGMEA solvent was dispensed thereon, left standing for 30 seconds, spin-dried, baked at 100 °C for 60 seconds to evaporate PGMEA, and the film thickness (b [nm]) was measured. The film thickness difference before and after PGMEA treatment (remaining film ratio: (b / a)×100) was determined.

[0212] Also, each of the silicon-containing antireflection film-forming compositions (UDL-1 to 12, Comparative Example UDL-1) prepared above and the antireflection film-forming compositions for comparative examples (Comparative Examples UDL2 and 3) was applied onto a silicon substrate. After the coating film was baked at 220 °C for 60 seconds to form an antireflection film, the optical constants (refractive index n, extinction coefficient k) of each antireflection film at a wavelength of 193 nm were determined using a variable angle spectroscopic ellipsometer (VASE) manufactured by J.A. Woollam Co., Ltd.

[0213] Also, the content of silicon contained in the silicon-containing antireflection film prepared above was determined by RBS (Rutherford backscattering spectrometry).

[0214] Each result is shown in Table 5 below.

[0215]

Table 5

[0216] Examples 1-1 to 1-12 using the silicon-containing antireflection film used in the pattern formation method of the present invention had a remaining film ratio ((b / a)×100) of 99% or more after PGMEA rinse treatment, indicating that a crosslinking reaction occurred and sufficient solvent resistance was exhibited. On the other hand, Comparative Example 1-1 using Comparative Example UDL-1 without a crosslinking agent had a solvent resistance of 99% or less, presumably because the thermosetting property was somewhat insufficient. Also, Comparative Example UDL-3 using Compound A1 used as the crosslinking agent for the silicon-containing antireflection film alone had a solvent resistance of 0%, presumably because the thermosetting property was insufficient.

[0217] Also, the optical constants of Examples 1-1 to 1-12 using 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. Although the optical constants also depend on the film thickness, the type of laminated film, etc., 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 in ArF immersion and high-NA exposure can be suppressed to a considerable extent, and it can be applied as an antireflection film for photoresist patterning (Figure 3). In the above Examples 1-1 to 1-12, the optical constants were all in a suitable range, indicating that they can be applied to photoresist patterning as a resist underlayer film.

[0218] [Examples 2 and Comparative Example 2: ArF Patterning Test] On a silicon wafer on which a silicon oxide film with a thickness of 200 nm was formed, as an organic underlayer film, 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 with a thickness of 35 nm. Next, on the organic underlayer film, as a silicon-containing hard mask, a silicon oxynitride film (SiON) was formed with a thickness of 15 nm. On top of that, each of the antireflection film-forming compositions (UDL-1 to 12, Comparative Examples UDL-1 to 2) was applied onto the SiON film and heated at 220°C for 60 seconds to form an antireflection film with a thickness of 10 nm.

[0219] Subsequently, an ArF resist solution for negative development (PR1) containing the following ArF resist polymer, acid generator, amine quencher, surfactant, and solvent in the composition shown in Table 6 was applied onto the silicon-containing antireflection film, and baked at 110°C for 60 seconds to form a resist upper layer film (photoresist film) with a film thickness of 70 nm. Thereby, a laminate was obtained.

[0220] [Chemical formula]

[0221] [Photoacid generator] (PAG-A): Triphenylsulfonium = 2-(adamantan-1-carbonyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonate (compound described in JP 2007-145797 A)

[0222] [Amine quencher] (Q-1): 2-Morpholinoethyl laurate

[0223] [Surfactant] Alkali-soluble surfactant (F-1): Poly(methacrylic acid = 3,3,3-trifluoro-2-hydroxy-1,1-dimethyl-2-trifluoromethylpropyl · methacrylic acid = 1,1,1-trifluoro-2-hydroxy-6-methyl-2-trifluoromethylhept-4-yl) (compound described in JP 2008-122932 A) Weight average molecular weight (Mw) = 7,300, dispersity (Mw / Mn) = 1.86

[0224] [Chemical formula]

[0225] [Table 6]

[0226] [Organic solvent] PGMEA: Propylene Glycol Monomethyl Ether Acetate CyHO: Cyclohexanone

[0227] For the photoresist film of the laminate obtained as described above, using an ArF immersion excimer laser stepper (manufactured by ASML, XT1900i, NA 1.35, σ 0.98 / 0.80, cross-pole aperture 30 degrees, 6% halftone phase shift mask), exposure was performed using a mask with hole patterns arranged on the wafer with a pitch of 90 nm and a width of 36 nm. After performing a heat treatment (PEB) for 60 seconds after exposure, butyl acetate was ejected from the development nozzle while rotating at 30 rpm for 3 seconds, and then stationary paddle development was performed for 27 seconds to obtain a negative resist pattern.

[0228] The hole dimensions of the resist pattern created under the above conditions were 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, and it was considered good when no trailing shape or undercut shape was observed, and was evaluated as bad when an obvious trailing shape or undercut shape was observed.

[0229] The reflectivity was calculated using PROLITH 2020a (Lithotech Japan Co., Ltd.). The film thickness of the antireflection film was fixed at 10 nm, and the results of calculating the reflectivity when the n of the antireflection film was 1.60 - 2.10 and the k was 0.20 - 0.40 are shown in Figure 3. An optical constant (n / k) that can reduce the reflected light from the underlying substrate during pattern exposure to 1.0% or less is preferable.

[0230] Using the above resist pattern (D layer) as a mask, the antireflection film (C layer) and the silicon-containing hard mask (B layer) were processed by dry etching under the following condition (1), and then the pattern was transferred to the organic underlayer film (A layer) under the following condition (2). Finally, the pattern was transferred to the oxide film (substrate to be processed) under the following condition (3).

[0231] (1) Processing conditions of the antireflection film (C layer) and the silicon-containing hard mask (B layer) Equipment: Dry etching equipment Telius SP manufactured by Tokyo Electron Limited Etching conditions (1): Chamber pressure: 80 mT RF power (upper): 500 W RF power (lower): 300 W CF 4 Gas flow rate: 150 sccm CHF 3 Gas flow rate: 50 sccm Time: 15 sec

[0232] (2) Processing conditions of the organic lower layer film (A layer) Chamber pressure: 80 mT RF power (upper): 500 W RF power (lower): 300 W CO 2 Gas flow rate: 320 sccm N 2 Gas flow rate: 80 sccm Time: 45 sec

[0233] (3) Processing conditions of the oxide film (substrate to be processed) Chamber pressure: 10 mT RF power (upper): 100 W RF power (lower): 800 W CF 4 Gas flow rate: 25 sccm CHF 3 Gas flow rate: 15 sccm O 2 Gas flow rate: 5 sccm Time: 60 sec

[0234] The hole dimensions of the pattern created under the above conditions were measured with an electron microscope (CG5000) manufactured by Hitachi High-Technologies Corporation. Also, the hole diameters at 50 different locations within the same exposure shot were measured, and the 3σ value of the dimensional variation was defined as CDU. The results are shown in Table 7. A smaller CDU value indicates better dimensional controllability and is preferable.

[0235]

Table 7

[0236] From the results in Table 7, it was found that in the examples (Examples 2-1 to 2-13) of the pattern formation method of the present invention, the cross-sectional pattern shape after exposure was good, and good CDU was shown after processing the substrate to be processed. In particular, Examples 2-1 to 2-12 using the ACL film for the organic underlayer film (A layer) showed excellent CDU. It is presumed that the ACL film has excellent pattern transferability because it has dry etching resistance to fluorine-based gas during processing of the substrate to be processed compared to the coating-type organic underlayer film (SOC film).

[0237] In Comparative Example 2-1, the cross-sectional pattern shape after exposure was an undercut shape. It is presumed that since the silicon-containing antireflection film was not used, the basic component generated from the SiON film migrated to the photoresist film, resulting in a decrease in the resolution of the resist. Also, combined with the insufficient reflection light suppression effect, it is presumed that the CDU of the resist pattern after exposure deteriorated, and the CDU after processing the substrate to be processed was also insufficient.

[0238] In Comparative Example 2-2, the cross-sectional pattern shape after exposure was an undercut shape. It is presumed that the poisoning suppression effect of Comparative Example UDL-1 used as the silicon-containing antireflection was insufficient, and the basic component generated from the SiON film migrated to the photoresist film, resulting in a decrease in the resolution of the resist. From the above results, it can be said that the silicon-containing antireflection film used in the present invention is preferably formed using a composition containing polysiloxane and a crosslinking agent in order to improve the denseness of the film.

[0239] In Comparative Example 2-3, the cross-sectional pattern shape after exposure was an undercut shape. It is presumed that this was because the poisoning suppression effect of the organic antireflection film (Comparative Example UDL-2) used for the antireflection film was insufficient. Also, combined with the insufficient reflection light suppression effect, it is presumed that the CDU of the resist pattern after exposure deteriorated, and the CDU after processing the substrate to be processed was also insufficient.

[0240] From the above, the pattern formation method using the silicon-containing antireflection film of the present invention has high adhesion to the resist pattern, has an effect of suppressing the collapse of fine patterns, has excellent antireflection effect and an effect of suppressing poisoning from the organic underlayer film to the photoresist film, and gives a pattern shape of a resist upper layer film with high rectangularity. Therefore, it is particularly preferably used in a multilayer resist process and is extremely useful in fine patterning for manufacturing semiconductor devices.

[0241] This specification includes the following aspects. [1] A pattern formation method, comprising: (1) A step of laminating (A) an organic underlayer film, (B) a silicon-containing hard mask, (C) a silicon-containing antireflection film, and (D) a photoresist film on a substrate to be processed in this order; (2) A step of exposing a 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) A step of using the obtained resist pattern as an etching mask to etch the (C) silicon-containing antireflection film and the (B) silicon-containing hard mask to form a hard mask intermediate film pattern; (4) A step of 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; (5) A step of using the obtained organic underlayer film pattern as an etching mask to etch the substrate to be processed to form a pattern on the substrate to be processed; and the (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film 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. A pattern formation method characterized by that.

Chemical formula

[0242] Note that the present invention is not limited to the above-described embodiments. The above embodiments are examples, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Explanation of Reference Numerals

[0243] 1... substrate, 2... layer to be processed, 2a... pattern (pattern formed in the layer to be processed), 3... organic underlayer film, 3a... organic underlayer film pattern, 4... silicon-containing hard mask film, 4a... hard mask intermediate film pattern, 5... silicon-containing antireflection film, 5a... silicon-containing antireflection film pattern, 6... photoresist film, 6a... resist pattern, 7... exposed portion, 10... substrate to be processed.

Claims

1. A pattern formation method, comprising: (1) a step of laminating, in this order, (A) an organic underlayer film, (B) a silicon-containing hard mask, (C) a silicon-containing antireflection film, and (D) a photoresist film on a substrate to be processed; (2) a step of exposing a 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) a step of using the obtained resist pattern as an etching mask to etch the (C) silicon-containing antireflection film and the (B) silicon-containing hard mask to form an intermediate hard mask film pattern; (4) a step of using the obtained intermediate hard mask film pattern as an etching mask to etch the (A) organic underlayer film to form an organic underlayer film pattern; (5) a step of using the obtained organic underlayer film pattern as an etching mask to etch the substrate to be processed to form a pattern on the substrate to be processed; characterized in that the (C) silicon-containing antireflection film is formed using a composition for forming a silicon-containing antireflection film 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. 【Chemical 1】 (wherein 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.)

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

3. In the general formulas (Sx-1) to (Sx-3), R ａ ~R ｃ The pattern forming method according to claim 1, wherein the silicon-containing antireflection film (C) is formed using the polysiloxane in which at least one of them is an organic group having one or more carbon-oxygen single bonds or carbon-oxygen double bonds.

4. The pattern formation method according to claim 1, wherein the (C) silicon-containing antireflection film is formed using a compound containing an isocyanuric acid structure as the crosslinking agent.

5. The pattern formation method according to claim 1, wherein the (A) organic underlayer film is formed by a CVD method.

6. The pattern formation method according to claim 1, wherein the (A) organic underlayer film is formed to contain any one of a graphene film, an amorphous carbon film, and a diamond-like carbon film.

7. The method for forming a pattern according to claim 1, wherein the (B) silicon-containing hard mask and the (C) silicon-containing antireflection film are formed such 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 FTb > FTc.

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

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