JP4220361B2 - Photoresist underlayer film forming material and pattern forming method - Google Patents

Description

The present invention relates to an underlayer film forming material effective as an antireflection film material used for microfabrication in a manufacturing process of a semiconductor element or the like, and far ultraviolet light, KrF excimer laser light, ArF excimer laser light (193 nm), F ₂ using the material. The present invention relates to a resist pattern forming method suitable for exposure to laser light (157 nm), Kr ₂ laser light (146 nm), and Ar ₂ laser light (126 nm).

  In recent years, with the increasing integration and speed of LSIs, there is a need for finer pattern rules. In lithography using light exposure, which is currently used as a general-purpose technology, the essence derived from the wavelength of the light source The resolution limit is approaching.

  As a light source for lithography used in forming a resist pattern, light exposure using a mercury lamp g-line (436 nm) or i-line (365 nm) as a light source is widely used, and as a means for further miniaturization, A method of shortening the wavelength of exposure light has been considered effective. For this reason, a short wavelength KrF excimer laser (248 nm) was used as an exposure light source in place of the i-line (365 nm) in the mass production process of the 64-Mbit DRAM processing method. However, in order to manufacture a DRAM having a degree of integration of 1G or more, which requires a finer processing technique (processing dimension is 0.13 μm or less), a light source with a shorter wavelength is required, and in particular, an ArF excimer laser (193 nm) is used. Lithography has been studied.

  On the other hand, conventionally, it is known that a two-layer resist method is excellent for forming a pattern with a high aspect ratio on a stepped substrate, and further, a two-layer resist film is developed with a general alkaline developer. Requires a high molecular silicone compound having a hydrophilic group such as a hydroxy group or a carboxyl group.

As the silicone-based chemically amplified positive resist material, a part of the phenolic hydroxyl group of polyhydroxybenzylsilsesquioxane, which is a stable alkali-soluble silicone polymer, is protected with a t-Boc group (t-butoxycarbonyl group). A silicone-based chemically amplified positive resist material for KrF excimer laser, which is used as a base resin and is combined with an acid generator, has been proposed (Patent Document 1, Non-Patent Document 1, etc.). For ArF excimer lasers, positive resists based on silsesquioxane in which cyclohexyl carboxylic acid is substituted with an acid labile group have been proposed (Patent Documents 2 to 3, Non-Patent Document 2). . Further, a positive resist based on silsesquioxane having hexafluoroisopropanol as a soluble group has been proposed for F ₂ laser (Patent Document 4). The polymer contains a polysilsesquioxane having a ladder skeleton formed by condensation polymerization of trialkoxysilane or trihalogenated silane in the main chain.

  As a resist base polymer in which silicon is pendant on a side chain, a silicon-containing (meth) acrylic ester-based polymer has been proposed (Patent Document 5 and Non-Patent Document 3).

  The lower layer film of the two-layer resist method is a hydrocarbon compound that can be etched with oxygen gas, and further serves as a mask when etching the underlying substrate, and therefore needs to have high etching resistance. In oxygen gas etching, it is necessary to be composed only of hydrocarbons that do not contain silicon atoms. In addition, in order to improve the line width controllability of the upper-layer silicon-containing resist and reduce pattern sidewall irregularities and pattern collapse due to standing waves, it also has a function as an antireflection film, specifically the lower layer It is necessary to suppress the reflectance from the film into the resist film to 1% or less.

  Here, when the underlying antireflection film for the single layer resist process is a highly reflective substrate such as polysilicon or aluminum, a material having an optimum refractive index (n value) and extinction coefficient (k value) is appropriately used. By setting the film thickness to a small value, reflection from the substrate can be reduced to 1% or less, and a very large effect can be exhibited. For example, at a wavelength of 193 nm, the refractive index of the resist is 1.7, the refractive index of the lower antireflection film (real part of refractive index) n = 1.5, and the extinction coefficient (imaginary part of refractive index) k = 0.5. If the film thickness is 42 nm, the reflectance is 0.5% or less (see FIG. 2). However, when there is a step on the base, the thickness of the antireflection film varies greatly on the step. The antireflection effect of the base uses not only the absorption of light but also the interference effect by setting the optimum film thickness, so the first base of 40 to 45 nm where the interference effect is strong also has a high antireflection effect. However, the reflectivity greatly varies depending on the film thickness. A material has been proposed in which the molecular weight of the base resin used for the antireflection film material is increased to suppress the film thickness fluctuation on the step and the conformal property is improved (Patent Document 6). There are problems such as pinholes that tend to occur after coating, problems that cannot be filtered, problems that the viscosity fluctuates over time and the film thickness changes, and problems that crystals deposit on the tip of the nozzle. Formality can be exhibited only at steps with relatively low height.

  Next, in a method employing a film thickness of the third base or more (170 nm or more) in which the reflectance variation due to film thickness variation is relatively small, the k value is between 0.2 and 0.3 and the film thickness is 170 nm. If it is above, the fluctuation | variation of the reflectance with respect to the change of a film thickness is small, and also a reflectance can be restrained to 1.5% or less. However, considering the etching load of the upper layer resist, there is a limit to increasing the thickness of the antireflection film, and at most, increasing the thickness of the second bottom of about 100 nm or less is the limit.

  When the base of the antireflection film is a transparent film such as an oxide film or a nitride film, and there is a step under the transparent film, the film thickness of the transparent film is not limited even if the surface of the transparent film is flattened by CMP or the like. Fluctuates. In this case, it is possible to make the film thickness of the antireflection film thereover constant, but if the film thickness of the base transparent film of the antireflection film varies, the thickness of the minimum reflection film shifts by the film thickness of the transparent film. It will be. Even if the film thickness of the antireflection film is set to the minimum reflection film thickness when the base is a reflection film, the reflectance may increase due to the film thickness variation of the transparent film.

  Antireflection film materials can be broadly classified into inorganic and organic materials. An inorganic system is a SiON film. This is formed by CVD using a mixed gas of silane and ammonia, and has a large etching selection ratio with respect to the resist. Therefore, there is an advantage that the etching load on the resist is small. is there. Since it is a basic substrate containing nitrogen atoms, there is a disadvantage that it tends to have a footing in a positive resist and an undercut profile in a negative resist.

  Organic systems can be spin-coated, do not require special equipment such as CVD or sputtering, can be peeled off at the same time as the resist, do not cause tailing, have a straight shape, and have good adhesion to the resist. There is an advantage, and antireflection films based on many organic materials have been proposed. For example, a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in Patent Document 7, an alkali-soluble resin and a light absorbent, or a maleic anhydride copolymer and a diamine type light absorbent described in Patent Document 8 A reaction product, a resin binder described in Patent Document 9 and a methylolmelamine-based thermal crosslinking agent, an acrylic resin-based type having a carboxylic acid group, an epoxy group, and a light-absorbing group in the same molecule, Patent Examples include those composed of methylolmelamine and a benzophenone-based light absorber described in Document 11, and those obtained by adding a low-molecular light absorber to the polyvinyl alcohol resin described in Patent Document 12. All of these take the method of adding a light absorber to the binder polymer or introducing it into the polymer as a substituent. However, since many of the light-absorbing agents have aromatic groups or double bonds, the addition of the light-absorbing agent increases the dry etching resistance and has a drawback that the dry etching selectivity with the resist is not so high. As the miniaturization progresses and the thinning of the resist is accelerated, the resist resistance of etching is reduced because the next generation ArF exposure uses acrylic or alicyclic polymer as the resist material. To do. Further, as described above, there is a problem that the thickness of the antireflection film must be increased. For this reason, etching is a serious problem, and there is a demand for an antireflection film having a high etching selectivity with respect to a resist, that is, a high etching speed.

  On the other hand, the function required as an antireflection film in the lower layer film for the two-layer resist process is different from that of the single-layer resist. Since the lower layer film for the two-layer resist process serves as a mask when etching the substrate, it must have high etching resistance under the conditions of substrate etching. As an antireflection film in a single layer resist process, a high etching rate is required to lighten the load on the single layer resist, whereas the reverse characteristics are required. Further, in order to ensure sufficient substrate etching resistance, the thickness of the lower layer film must be increased to 300 nm or more, which is equal to or higher than that of the single layer resist. When the film thickness is 300 nm or more, the change in reflectance due to the change in film thickness almost converges, and the antireflection effect by phase difference control cannot be expected.

  Here, the results of calculating the reflectance up to a maximum film thickness of 500 nm are shown in FIGS. Assuming that the exposure wavelength is 193 nm, the n value of the upper layer resist is 1.74, and the k value is 0.02, the k value of the lower layer film is fixed at 0.3 in FIG. -2.0, the horizontal axis represents the substrate reflectance when the film thickness is varied in the range of 0 to 500 nm. Assuming a lower layer film for a two-layer resist having a film thickness of 300 nm or more, the reflectance can be reduced to 1% or less in the range of 1.6 to 1.9, which is the same as or slightly higher than the upper layer resist. An optimal value exists.

  FIG. 4 shows the reflectance when the n value is fixed at 1.5 and the k value is varied in the range of 0.1 to 0.8. The reflectance can be reduced to 1% or less when the k value is in the range of 0.24 to 0.15. On the other hand, the optimum k value of the antireflection film for a single layer resist used in a thin film of about 40 nm is 0.4 to 0.5, which is different from the optimum k value of the lower layer for a two layer resist of 300 nm or more. It has been shown that a lower layer for a two-layer resist requires a lower k value, that is, a higher transparent lower layer film.

  Here, as an underlayer film forming material for 193 nm, a copolymer of polyhydroxystyrene and acrylic has been studied as introduced in Non-Patent Document 4. Polyhydroxystyrene has a very strong absorption at 193 nm, and the k value alone is a high value of around 0.6. Therefore, the k value is adjusted to around 0.25 by copolymerizing with acrylic whose k value is almost zero.

  However, with respect to polyhydroxystyrene, the etching resistance of acrylic on the substrate etching is weak, and in order to lower the k value, a considerable proportion of acrylic must be copolymerized, resulting in a considerable decrease in the resistance of substrate etching. To do. The resistance to etching appears not only in the etching rate but also in the occurrence of surface roughness after etching. The increase in surface roughness after etching becomes more prominent as a result of acrylic copolymerization.

  One of the ones having higher transparency at 193 nm and higher etching resistance than a benzene ring is a naphthalene ring. Patent Document 13 proposes a lower layer film having a naphthalene ring and an anthracene ring. However, the k value of naphthol co-condensed novolak resin and polyvinyl naphthalene resin is between 0.3 and 0.4, and the target transparency of 0.1 to 0.3 has not been achieved. I have to raise it. Further, the n value at 193 nm of the naphthol co-condensed novolak resin and the polyvinyl naphthalene resin is low, and as a result of measurement by the present inventors, it is 1.4 for the naphthol co-condensed novolak resin and 1.2 for the polyvinyl naphthalene resin. . Also in the acenaphthylene polymer shown by patent documents 14-15, the n value in 193 nm is low compared with wavelength 248 nm, k value is high, and both have not reached the target value. There is a need for a lower layer film that has a high n value, a low k value, is transparent, and has high etching resistance.

JP-A-6-118651 Japanese Patent Laid-Open No. 10-324748 JP-A-11-302382 JP 2002-55456 A JP-A-9-110938 Japanese Patent Laid-Open No. 10-69072 Japanese Patent Publication No. 7-69611 US Pat. No. 5,294,680 Japanese Patent Laid-Open No. 6-118631 JP-A-6-118656 JP-A-8-87115 JP-A-8-179509 JP 2002-14474 A JP 2001-40293 A JP 2002-214777 A JP 2000-294504 A SPIE vol. 1925 (1993) p377 SPIE vol. 3333 (1998) p62 J. et al. Photopolymer Sci. and Technol. Vol. 9 No. 3 (1996) p435-446 SPIE Vol. 4345 (2001) p50 Proc. SPIE Vol. 2195, p225-229 (1994)

  The problem to be solved by the present invention is that it functions as an excellent antireflection film, particularly as a lower layer film for a silicon-containing two-layer resist process, and corresponds to all wavelengths of 248 nm, 193 nm, and 157 nm. It is an object of the present invention to provide an underlayer film forming material and a pattern forming method that have optimum n and k values than novolak, naphthol novolak, etc., and have excellent etching resistance in substrate processing.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have found that in a substituted polyhydroxystyrene substituted with a predetermined substituent, an optimum n is obtained at 248 nm, 193 nm, and 157 nm depending on the type of substituent and the substitution rate. It has been found that the material is a promising material as a lower layer film for a silicon-containing two-layer resist process having a value and a k value and excellent in etching resistance, and has led to the present invention.

  That is, the present invention is a novel lower layer film applicable to a silicon-containing bilayer process, and is particularly excellent in an antireflection effect with a film thickness of 200 nm or more at wavelengths of 248 nm, 193 nm, and 157 nm, and is excellent in etching resistance. This material proposes a material based on a substituted polystyrene substituted with, which can suppress substrate reflection at a film thickness of 200 nm or more by having an optimum n value and k value. It is characterized by excellent etching resistance under conditions.

（一般式（１）中、Ｒ^１は水素原子又はメチル基を表し、Ｒ^２は水素原子、炭素数１〜１０のアルキル基、炭素数１〜１０のヒドロキシ基含有アルキル基、炭素数１〜１０のアシル基、又はグリシジル基を表し、Ｒ^３は一般式（２）で示される１価の有機基である。一般式（２）中、Ｒ^４は炭素数１〜４のアルキレン基を表し、Ｒ^５は炭素数４〜２０の直鎖状、分岐状もしくは環状のアルキル基（直鎖状、分岐状は参考例）又は炭素数６〜２０のアリール基を表し、ヒドロキシ基、エーテル基又はエステル基を含んでいてもよい。ｍは１又は２、ｎは１又は２である。）
また、この材料を用いて基板上に下層膜を形成するステップと、該下層膜の上にフォトレジスト組成物を用いてフォトレジスト膜を形成するステップと、該フォトレジスト膜のパターン回路領域を露光するステップと、その後の現像液で現像して該フォトレジスト膜にレジストパターンを形成するステップと、該レジストパターンが形成されたフォトレジスト膜をマスクにして該下層膜及び該基板をエッチングするステップを含んでなるパターン形成方法を提供する。
さらに、この材料を用いて基板上に下層膜を形成するステップと、該下層膜の上にフォトレジスト組成物を用いてフォトレジスト膜を形成するステップと、該フォトレジスト膜のパターン回路領域を露光するステップと、その後の現像液で現像して該フォトレジスト膜にレジストパターンを形成するステップと、該レジストパターンが形成されたフォトレジスト膜をマスクにして該下層膜をエッチングするステップと、さらにパターンが形成された下層膜をマスクにして該基板をエッチングして該基板にパターンを形成するステップを含んでなるパターン形成方法を提供する。
なお、露光は、好ましくは波長３００ｎｍ以下の高エネルギー線又は電子線を用い、より好ましくは、遠紫外線、ＫｒＦエキシマレーザー光、ＡｒＦエキシマレーザー光（１９３ｎｍ）、Ｆ_２レーザー光（１５７ｎｍ）、Ｋｒ_２レーザー光（１４６ｎｍ）、Ａｒ_２レーザー光（１２６ｎｍ）を用いる。
Accordingly, the present invention provides the following pattern forming method and a lower layer film forming material used therefor.
Provided is a photoresist underlayer film forming material for forming an underlayer film of a photoresist layer, which contains a polymer comprising a repeating unit represented by the following general formula (1).

(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a hydroxy group-containing alkyl group having 1 to 10 carbon atoms, or 1 to 1 carbon atom. 10 represents an acyl group or a glycidyl group, and R ³ is a monovalent organic group represented by the general formula (2), wherein R ⁴ represents an alkylene group having 1 to ⁴ carbon atoms. , R ⁵ represents a linear, branched or cyclic alkyl group having 4 to 20 carbon atoms (linear or branched is a reference example) or an aryl group having 6 to 20 carbon atoms, a hydroxy group, an ether group or (It may contain an ester group. M is 1 or 2, and n is 1 or 2.)
Also, a step of forming a lower layer film on the substrate using the material, a step of forming a photoresist film using a photoresist composition on the lower layer film, and exposing a pattern circuit region of the photoresist film A step of developing with a developing solution to form a resist pattern on the photoresist film, and a step of etching the lower layer film and the substrate using the photoresist film on which the resist pattern is formed as a mask. A pattern forming method is provided.
Further, a step of forming a lower layer film on the substrate using the material, a step of forming a photoresist film using a photoresist composition on the lower layer film, and exposing a pattern circuit region of the photoresist film A step of developing with a developing solution to form a resist pattern on the photoresist film, a step of etching the lower layer film using the photoresist film on which the resist pattern is formed as a mask, and a pattern A pattern forming method comprising a step of etching the substrate using the lower layer film on which is formed as a mask to form a pattern on the substrate.
The exposure is preferably performed using a high energy beam or electron beam having a wavelength of 300 nm or less, and more preferably far ultraviolet light, KrF excimer laser light, ArF excimer laser light (193 nm), F ₂ laser light (157 nm), or Kr _2. Laser light (146 nm) and Ar ₂ laser light (126 nm) are used.

The underlayer film forming material of the present invention has a refractive index n value of 1.5 to 1.9, k value of 0.15 to 0.4, and a sufficient antireflection effect with a film thickness of 200 nm or more. It has an extinction coefficient that can be exhibited, and the etching rate of CF ₄ / CHF ₃ gas and Cl ₂ / BCl ₃ gas used for substrate processing is comparable to that of novolak resin and has high etching resistance. Also, the resist shape after patterning is good.

Hereinafter, the present invention will be described in more detail.
In the pattern forming method of the present invention, a photoresist underlayer film containing a substituted polystyrene substituted with a predetermined substituent is applied as a photoresist underlayer film on a substrate, and a layer of a photoresist composition is applied over the underlayer film. Then, the pattern circuit region is irradiated with radiation, developed with a developing solution to form a resist pattern, and the lower layer film layer and the substrate are processed using a photoresist layer as a mask with a dry etching apparatus. The lower layer film forming material used here has (A) a substituted polystyrene substituted with a predetermined substituent as an essential component, preferably from (B) an organic solvent, (C) a crosslinking agent, and (D) an acid generator. It contains one or more selected from the group.

As substituted polystyrene substituted by the predetermined substituent of the said (A) component, what is represented by the said General formula (1) is preferable.
Hydroxystyrene for obtaining the repeating unit listed in the general formula (1) is o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, α-methyl-p-hydroxystyrene, p-acetoxystyrene, p-pivalloy. Examples include loxystyrene, p-ethoxyethoxystyrene, pt butoxystyrene, pt amyloxystyrene, and the like.
Specific examples of the substituent —R ⁴ —R ⁵ represented by the general formula (2) include the following.

  Among these, an anthracene methyl group is most preferably used for 248 nm. In order to improve etching resistance and transparency at 193 nm, those having an alicyclic structure and those having a naphthalene structure are preferably used. On the other hand, since the benzene ring has a window with improved transparency at a wavelength of 157 nm, it is necessary to increase the absorption by shifting the absorption wavelength. The furan ring has a shorter absorption than the benzene ring and slightly improves the absorption at 157 nm, but the effect is small. Naphthalene rings, anthracene rings, and pyrene rings are preferably used because absorption increases when the absorption wavelength is increased, and these aromatic rings also have an effect of improving etching resistance.

Examples of the method of introducing the substituent of the general formula (2) include a method of introducing an alcohol represented by the following general formula (3) into the ortho position of the hydroxy group of the phenol in the presence of an acid catalyst.

  The substituent of General formula (2) can be introduce | transduced into the monomer before superposition | polymerization, and can also be introduce | transduced into the polymer after superposition | polymerization.

Although the present invention is based on a polymer of substituted styrene, it may be copolymerized with other monomers. Examples of the copolymerizable monomer include indene, indole, acrylic derivative, methacryl derivative, norbornadiene derivative, norbornene derivative, maleic anhydride, maleimide derivative, acenaphthylene derivative, vinyl naphthalene derivative, vinyl anthracene derivative, vinyl ether derivative, allyl ether derivative, acetic acid. Examples thereof include vinyl, acrylonitrile, methacrylonitrile, vinyl pyrrolidone, tetrafluoroethylene, and the like, and a binary or higher copolymer including these may be used.
It is also possible to copolymerize hydroxystyrene in which the substituent of the general formula (2) is not pendant.
When a copolymer is used, the substituted styrene monomer of the present invention is preferably a polymer containing 5 mol% or more and less than 100 mol%.

The copolymer used in the present invention preferably contains a repeating unit selected from the following general formulas (4) to (6) in addition to the repeating units of the general formulas (1) and (2).

In general formulas (4) to (6), R ⁶ and R ⁷ independently represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, R ⁸ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a hydroxy group, or an alkoxycarbonyl group, X represents a methylene group, an oxygen atom, or a sulfur atom, and p and q is each independently 0 or an integer of 1-4.

  In order to synthesize these polymer compounds, one method is to carry out heat polymerization by adding a radical initiator to a hydroxystyrene monomer in an organic solvent. Monomers containing a hydroxy group can be copolymerized, but the molecular weight is narrowly dispersed by replacing the acetoxy group with an acetoxy group and subjecting the resulting polymer compound to alkali hydrolysis in an organic solvent to deprotect the acetoxy group. There is an advantage that can be realized.

  Examples of the organic solvent used at the time of polymerization include toluene, benzene, tetrahydrofuran, diethyl ether, dioxane and the like. As polymerization initiators, 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2-azobis (2-methylpropionate) ), Benzoyl peroxide, lauroyl peroxide, and the like, preferably polymerized by heating to 50 to 80 ° C. The reaction time is 2 to 100 hours, preferably 5 to 20 hours. Ammonia water, triethylamine, etc. can be used as the base during the alkali hydrolysis. The reaction temperature is −20 to 100 ° C., preferably 0 to 60 ° C., and the reaction time is 0.2 to 100 hours, preferably 0.5 to 20 hours.

  The weight average molecular weight of the polymer used in the present invention is preferably in the range of 1,500 to 200,000, more preferably in the range of 2,000 to 100,000, in terms of polystyrene using gel permeation chromatography (GPC). The molecular weight distribution is not particularly limited, and low molecular weight and high molecular weight substances can be removed by fractionation to reduce the degree of dispersion. The weight of two or more general formulas (1) having different molecular weights and degrees of dispersion can be reduced. Two or more polymers of the general formula (1) having different composition ratios may be mixed.

  Hydrogenation can be performed in order to further improve the transparency at 193 nm of the resin of the general formula (1) of the present invention. A preferable hydrogenation ratio is 80 mol% or less of an aromatic group such as phenol.

  The base resin for the underlayer film-forming material of the present invention is characterized by containing specific substituent-containing polystyrene, but can also be blended with conventional polymers mentioned as the above-mentioned antireflection film material. Substituted polyhydroxystyrene has a glass transition point of 150 ° C. or higher, and this alone may have poor deep hole filling characteristics such as via holes. In order to embed holes without generating voids, a technique is adopted in which a polymer having a low glass transition point is used and resin is embedded in the bottom of the holes while heat-flowing at a temperature lower than the crosslinking temperature (Patent Document 16). . Polymers having a low glass transition point, especially polymers having a glass transition point of 180 ° C. or lower, particularly 100 to 170 ° C., such as acrylic derivatives, vinyl alcohol, vinyl ethers, allyl ethers, styrene derivatives, allylbenzene derivatives, ethylene, propylene, butadiene By blending with olefins such as the above, polymers by metathesis ring-opening polymerization, etc., the glass transition point can be lowered, and the via hole filling properties can be improved.

As another method for lowering the glass transition point, a hydroxyl group of a hydroxy group of a substituted polyhydroxystyrene is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a t-butyl group, a t-amyl group. A group, an acid labile group such as acetal, an acetyl group, a pivaloyl group, and the like.
The substitution rate at this time is in the range of 10 to 60 mol%, preferably 15 to 50 mol% of the hydroxyl group of the substituted polyhydroxystyrene.

  One of the performances required for the lower layer film including the antireflection film is that there is no intermixing with the resist and that no low molecular component diffuses into the resist layer (Non-Patent Document 5). In order to prevent these problems, a method is generally employed in which thermal crosslinking is performed by baking after spin coating of the antireflection film. Therefore, when a crosslinking agent is added as a component of the antireflection film material, a method of introducing a crosslinkable substituent into the polymer may be used.

  Specific examples of the crosslinking agent that can be used in the present invention include a melamine compound, a guanamine compound, a glycoluril compound, or a urea compound substituted with at least one group selected from a methylol group, an alkoxymethyl group, and an acyloxymethyl group. Examples of the compound include a double bond such as an epoxy compound, a thioepoxy compound, an isocyanate compound, an azide compound, and an alkenyl ether group. These may be used as additives, but may be introduced as pendant groups in the polymer side chain. A compound containing a hydroxy group is also used as a crosslinking agent.

Among the various compounds that can be used as the crosslinking agent, examples of the epoxy compound include tris (2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triethylolethane triglycidyl ether, and the like. Is exemplified.
Specific examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, and a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, Examples thereof include compounds in which 1 to 6 methylol groups of hexamethylolmelamine are acyloxymethylated, or a mixture thereof.
Examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated, and a mixture thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, and tetramethylolguanamine. Examples include compounds in which 4 methylol groups are acyloxymethylated and mixtures thereof.
Examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethylglycoluril, a compound in which 1 to 4 of the methylol groups of tetramethylolglycoluril are methoxymethylated, or a mixture thereof, tetramethylolglycoluril Or a mixture thereof in which 1 to 4 of the methylol groups are acyloxymethylated.
Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated, or a mixture thereof, tetramethoxyethyl urea, and the like.

  Examples of the compound containing an alkenyl ether group that can be used as a crosslinking agent include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, Neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, trimethylolpropane trivinyl ether, etc. Is mentioned.

When the hydroxy group of the phenol-dicyclopentadiene resin of the general formula (1) is substituted with a glycidyl group, it is effective to add a compound containing a hydroxy group. Particularly preferred are compounds containing two or more hydroxy groups in the molecule. For example, naphthol novolak, m- and p-cresol novolak, naphthol-dicyclopentadiene novolak, m- and p-cresol-dicyclopentadiene novolak, 4,8-bis (hydroxymethyl) tricyclo [5.2.1.0. ^2,6 ] -decane, pentaerythritol, 1,2,6-hexanetriol, 4,4 ′, 4 ″ -methylidenetriscyclohexanol, 4,4 ′-[1- [4- [1- (4 -Hydroxycyclohexyl) -1-methylethyl] phenyl] ethylidene] biscyclohexanol, [1,1'-bicyclohexyl] -4,4'-diol, methylenebiscyclohexanol, decahydronaphthalene-2,6-diol, Alcohols such as [1,1′-bicyclohexyl] -3,3 ′, 4,4′-tetrahydroxy Group-containing compounds, bisphenol, methylene bisphenol, 2,2′-methylene bis [4-methylphenol], 4,4′-methylidene-bis [2,6-dimethylphenol], 4,4 ′-(1-methyl-ethylidene ) Bis [2-methylphenol], 4,4′-cyclohexylidene bisphenol, 4,4 ′-(1,3-dimethylbutylidene) bisphenol, 4,4 ′-(1-methylethylidene) bis [2, 6-dimethylphenol], 4,4′-oxybisphenol, 4,4′-methylenebisphenol, bis (4-hydroxyphenyl) methanone, 4,4′-methylenebis [2-methylphenol], 4,4′- [1,4-phenylenebis (1-methylethylidene)] bisphenol, 4,4 ′-(1,2-ethanediyl) bisphenol, 4 4 ′-(diethylsilylene) bisphenol, 4,4 ′-[2,2,2-trifluoro-1- (trifluoromethyl) ethylidene] bisphenol, 4,4 ′, 4 ″ -methylidenetrisphenol, 4 , 4 ′-[1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, 2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol, 4, , 4 ′, 4 ″ -Ethyridinetris [2-methylphenol], 4,4 ′, 4 ″ -Ethiridinetrisphenol, 4,6-bis [(4-hydroxyphenyl) methyl] 1,3- Benzenediol, 4,4 ′-[(3,4-dihydroxyphenyl) methylene] bis [2-methylphenol], 4,4 ′, 4 ″, 4 ′ ″-(1,2-ethanediylidene) tetra Sphenol, 4,4 ′, 4 ″, 4 ′ ″-ethanediylidene) tetrakis [2-methylphenol], 2,2′-methylenebis [6-[(2-hydroxy-5-methylphenyl) methyl]- 4-methylphenol], 4,4 ′, 4 ″, 4 ′ ″-(1,4-phenylenedimethylidine) tetrakisphenol, 2,4,6-tris (4-hydroxyphenylmethyl) 1,3- Benzenediol, 2,4 ′, 4 ″ -methylidenetrisphenol, 4,4 ′, 4 ′ ″-(3-methyl-1-propanyl-3-ylidene) trisphenol, 2,6-bis [( 4-hydroxy-3-fluorophenyl) methyl] -4-fluorophenol, 2,6-bis [4-hydroxy-3-fluorophenyl] methyl] -4-fluorophenol, 3,6-bis "(3,5 -Dimethyl- 4-hydroxyphenyl) methyl "1,2-benzenediol, 4,6-bis" (3,5-dimethyl-4-hydroxyphenyl) methyl "1,3-benzenediol, p-methylcalix [4] arene, 2,2′-methylenebis [6-[(2,5 / 3,6-dimethyl-4 / 2-hydroxyphenyl) methyl] -4-methylphenol, 2,2′-methylenebis [6-[(3,5 -Dimethyl-4-hydroxyphenyl) methyl] -4-methylphenol, 4,4 ′, 4 ″, 4 ′ ″-tetrakis [(1-methylethylidene) bis (1,4-cyclohexylidene)] phenol 6,6′-methylenebis [4- (4-hydroxyphenylmethyl) -1,2,3-benzenetriol, 3,3 ′, 5,5′-tetrakis [(5-methyl-2-hydroxypheny ) Methyl] - [(1,1'-biphenyl) -4,4'-diol] phenol low nuclear bodies and the like.

  The blending amount of the crosslinking agent in the present invention is preferably 5 to 50 parts by weight, particularly preferably 10 to 40 parts by weight, based on 100 parts by weight of the base resin (total resin). If it is less than 5 parts by weight, it may cause mixing with the resist. If it exceeds 50 parts by weight, the antireflection effect may be reduced, or the film after crosslinking may be cracked.

  In the present invention, an acid generator for further promoting the crosslinking reaction by heat can be added. There are acid generators that generate an acid by thermal decomposition and those that generate an acid by light irradiation, and any of them can be added.

As the acid generator used in the present invention,
i. An onium salt of the following general formula (P1a-1), (P1a-2), (P1a-3) or (P1b),
ii. A diazomethane derivative of the following general formula (P2):
iii. A glyoxime derivative of the following general formula (P3):
iv. A bissulfone derivative of the following general formula (P4):
v. A sulfonic acid ester of an N-hydroxyimide compound of the following general formula (P5),
vi. β-ketosulfonic acid derivatives,
vii. Disulfone derivatives,
viii. Nitrobenzyl sulfonate derivatives,
ix. Examples thereof include sulfonic acid ester derivatives.

(In the above formula, each of R ^101a , R ^101b and R ^101c is a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, an alkenyl group, an oxoalkyl group or an oxoalkenyl group, and having 6 to 20 carbon atoms. An aryl group, an aralkyl group having 7 to 12 carbon atoms, or an aryloxoalkyl group, part or all of hydrogen atoms of which may be substituted with an alkoxy group, etc. R ^101b and R ^101c and may form a ring, when they form a ring, R ^101b, .K indicating each is R ^101c alkylene group having 1 to 6 carbon atoms ^- .R ^101d is representative of a non-nucleophilic counter ion R ^101e , R ^101f and R ^101g are represented by adding a hydrogen atom to R ^101a , R ^101b and R ^101c , R ^101d and R ^101e , or R ^101d and R ^101e and R ^101f form a ring. In the case of forming a ring, R ^101d and R ^101e or R ^101d And R ^101e and R ^101f represent a C3-C10 alkylene group or a heteroaromatic ring having a nitrogen atom in the formula (P1a-3) in the ring.

R ^101a , R ^101b , R ^101c , R ^101d , R ^101e , R ^101f and R ^101g may be the same as or different from each other. Specifically, as the alkyl group, a methyl group, an ethyl group, Propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclopropylmethyl group, 4- Examples thereof include a methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, an adamantyl group and the like. Examples of the alkenyl group include a vinyl group, an allyl group, a propenyl group, a butenyl group, a hexenyl group, and a cyclohexenyl group. Examples of the oxoalkyl group include 2-oxocyclopentyl group, 2-oxocyclohexyl group, and the like. 2-oxopropyl group, 2-cyclopentyl-2-oxoethyl group, 2-cyclohexyl-2-oxoethyl group, 2- (4 -Methylcyclohexyl) -2-oxoethyl group and the like can be mentioned. Examples of the aryl group include a phenyl group, a naphthyl group, a p-methoxyphenyl group, an m-methoxyphenyl group, an o-methoxyphenyl group, an ethoxyphenyl group, a p-tert-butoxyphenyl group, and an m-tert-butoxyphenyl group. Alkylphenyl groups such as alkoxyphenyl groups, 2-methylphenyl groups, 3-methylphenyl groups, 4-methylphenyl groups, ethylphenyl groups, 4-tert-butylphenyl groups, 4-butylphenyl groups, dimethylphenyl groups, etc. Alkyl naphthyl groups such as methyl naphthyl group and ethyl naphthyl group, alkoxy naphthyl groups such as methoxy naphthyl group and ethoxy naphthyl group, dialkyl naphthyl groups such as dimethyl naphthyl group and diethyl naphthyl group, dimethoxy naphthyl group and diethoxy naphthyl group Dialkoxynaphthyl group And the like. Examples of the aralkyl group include a benzyl group, a phenylethyl group, and a phenethyl group. As the aryloxoalkyl group, 2-aryl-2-oxoethyl group such as 2-phenyl-2-oxoethyl group, 2- (1-naphthyl) -2-oxoethyl group, 2- (2-naphthyl) -2-oxoethyl group and the like Groups and the like.

Non-nucleophilic counter ions of K ⁻ include halide ions such as chloride ions and bromide ions, triflate, fluoroalkyl sulfonates such as 1,1,1-trifluoroethanesulfonate, nonafluorobutanesulfonate, tosylate, and benzene. Examples thereof include aryl sulfonates such as sulfonate, 4-fluorobenzene sulfonate and 1,2,3,4,5-pentafluorobenzene sulfonate, and alkyl sulfonates such as mesylate and butane sulfonate.

Further, R ^101d , R ^101e , R ^101f and R ^{101g each} have a heteroaromatic ring having a nitrogen atom in the formula (P1a-3) in the ring, such as an imidazole derivative (for example, imidazole, 4-methylimidazole, 4-methyl -2-phenylimidazole, etc.), pyrazole derivatives, furazane derivatives, pyrroline derivatives (eg pyrroline, 2-methyl-1-pyrroline etc.), pyrrolidine derivatives (eg pyrrolidine, N-methylpyrrolidine, pyrrolidinone, N-methylpyrrolidone etc.), Imidazoline derivatives, imidazolidine derivatives, pyridine derivatives (eg pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4- (1-butylpentyl) pyridine, dimethylpyridine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl -2- Phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone, 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2- ( 1-ethylpropyl) pyridine, aminopyridine, dimethylaminopyridine, etc.), pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives, pyrazoline derivatives, pyrazolidine derivatives, piperidine derivatives, piperazine derivatives, morpholine derivatives, indole derivatives, isoindole derivatives, 1H-indazole Derivatives, indoline derivatives, quinoline derivatives (eg quinoline, 3-quinolinecarbonitrile, etc.), isoquinoline derivatives, cinnoline derivatives, quinazoline derivatives, quinoxaline derivatives Conductor, phthalazine derivative, purine derivative, pteridine derivative, carbazole derivative, phenanthridine derivative, acridine derivative, phenazine derivative, 1,10-phenanthroline derivative, adenine derivative, adenosine derivative, guanine derivative, guanosine derivative, uracil derivative, uridine derivative, etc. Is exemplified.

  (P1a-1) and (P1a-2) have the effects of both a photoacid generator and a thermal acid generator, while (P1a-3) acts as a thermal acid generator.

(In the above formula, R ^102a and R ^102b each independently represents a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms. R ¹⁰³ is a linear or branched structure having 1 to 10 carbon atoms. Or a cyclic alkylene group, R ^104a and R ^104b each independently represents a 2-oxoalkyl group having 3 to 7 carbon atoms, and K ⁻ represents a non-nucleophilic counter ion.)

Specific examples of R ^102a and R ^102b include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl. Group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group and the like.

R ¹⁰³ is methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, 1,4-cyclohexylene group, 1,2-cyclohexylene. Group, 1,3-cyclopentylene group, 1,4-cyclooctylene group, 1,4-cyclohexanedimethylene group and the like.

^{Examples of} R ^104a and R ^104b include a 2-oxopropyl group, a 2-oxocyclopentyl group, a 2-oxocyclohexyl group, and a 2-oxocycloheptyl group.

Examples of K ⁻ are the same as those described in the formulas (P1a-1), (P1a-2), and (P1a-3).

(In the above formula, R ¹⁰⁵ and R ¹⁰⁶ are each independently a linear, branched or cyclic alkyl group or halogenated alkyl group having 1 to 12 carbon atoms, aryl group or halogenated aryl group having 6 to 20 carbon atoms. Or an aralkyl group having 7 to 12 carbon atoms.)

^Examples of the alkyl group represented by R ¹⁰⁵ and R ¹⁰⁶ include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, Examples include amyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, norbornyl group, adamantyl group and the like. Examples of the halogenated alkyl group include a trifluoromethyl group, a 1,1,1-trifluoroethyl group, a 1,1,1-trichloroethyl group, and a nonafluorobutyl group.

^Examples of the aryl group of R ¹⁰⁵ and R ¹⁰⁶ include phenyl group, p-methoxyphenyl group, m-methoxyphenyl group, o-methoxyphenyl group, ethoxyphenyl group, p-tert-butoxyphenyl group, m-tert-butoxyphenyl. Alkylphenyl such as alkoxyphenyl group such as 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, ethylphenyl group, 4-tert-butylphenyl group, 4-butylphenyl group and dimethylphenyl group Groups. Examples of the halogenated aryl group include a fluorophenyl group, a chlorophenyl group, and 1,2,3,4,5-pentafluorophenyl group.
^Examples of the aralkyl group for R ¹⁰⁵ and R ¹⁰⁶ include a benzyl group and a phenethyl group.

(In the above formula, R ¹⁰⁷ , R ¹⁰⁸ and R ¹⁰⁹ are independently a linear, branched or cyclic alkyl group or halogenated alkyl group having 1 to 12 carbon atoms, aryl group or halogen having 6 to 20 carbon atoms. An aryl group or an aralkyl group having 7 to 12 carbon atoms, R ¹⁰⁸ and R ¹⁰⁹ may be bonded to each other to form a cyclic structure, and when forming a cyclic structure, R ¹⁰⁸ and R ¹⁰⁹ are each independently And represents a linear or branched alkylene group having 1 to 6 carbon atoms.)

Examples of the alkyl group, halogenated alkyl group, aryl group, halogenated aryl group, and aralkyl group of R ¹⁰⁷ , R ¹⁰⁸ , and R ¹⁰⁹ include the same groups as those described for R ¹⁰⁵ and R ¹⁰⁶ . ^Examples of the alkylene group for R ¹⁰⁸ and R ¹⁰⁹ include a methylene group, an ethylene group, a propylene group, a butylene group, and a hexylene group.

（上式中、Ｒ^101a、Ｒ^101bは上記と同様である。）

(In the above formula, R ^101a and R ^101b are the same as above.)

(In the above formula, R ¹¹⁰ represents an arylene group having 6 to 10 carbon atoms, an alkylene group having 1 to 6 carbon atoms, or an alkenylene group having 2 to 6 carbon atoms, and some or all of the hydrogen atoms of these groups are further It may be substituted with a linear or branched alkyl or alkoxy group having 1 to 4 carbon atoms, a nitro group, an acetyl group, or a phenyl group, and R ¹¹¹ is a linear or branched group having 1 to 8 carbon atoms. Or a substituted alkyl group, an alkenyl group or an alkoxyalkyl group, a phenyl group, or a naphthyl group, and some or all of the hydrogen atoms of these groups are further an alkyl group or an alkoxy group having 1 to 4 carbon atoms; A phenyl group optionally substituted with an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group or an acetyl group; a heteroaromatic group having 3 to 5 carbon atoms; or a chlorine atom or a fluorine atom Replace It may be.)

^Examples of the arylene group for R ¹¹⁰ include a 1,2-phenylene group and a 1,8-naphthylene group. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a phenylethylene group, and a norbornane- 2,3-diyl group etc. are mentioned, As the alkenylene group, 1,2-vinylene group, 1-phenyl-1,2-vinylene group, 5-norbornene-2,3-diyl group and the like can be mentioned.

^Examples of the alkyl group of R ¹¹¹ include the same groups as R ^{101a to} R ^101c, and examples of the alkenyl group include a vinyl group, 1-propenyl group, allyl group, 1-butenyl group, 3-butenyl group, isoprenyl group, 1-pentenyl group, 3-pentenyl group, 4-pentenyl group, dimethylallyl group, 1-hexenyl group, 3-hexenyl group, 5-hexenyl group, 1-heptenyl group, 3-heptenyl group, 6-heptenyl group, 7 -Octenyl group and the like, and as the alkoxyalkyl group, methoxymethyl group, ethoxymethyl group, propoxymethyl group, butoxymethyl group, pentyloxymethyl group, hexyloxymethyl group, heptyloxymethyl group, methoxyethyl group, Ethoxyethyl group, propoxyethyl group, butoxyethyl group, pentyloxyethyl group, hexyloxyethyl , Methoxypropyl, ethoxypropyl, propoxypropyl group, butoxy propyl group, methoxybutyl group, ethoxybutyl group, propoxybutyl group, a methoxy pentyl group, an ethoxy pentyl group, a methoxy hexyl group, a methoxy heptyl group.

Examples of the optionally substituted alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. Examples of the alkoxy group having 1 to 4 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, and a tert-butoxy group.
Examples of the phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group or an acetyl group include a phenyl group, a tolyl group, a p-tert-butoxyphenyl group, p -Acetylphenyl group, p-nitrophenyl group, etc. are mentioned, As a C3-C5 heteroaromatic group, a pyridyl group, a furyl group, etc. are mentioned.

  Specifically, examples of onium salts include tetramethylammonium trifluoromethanesulfonate, tetramethylammonium nonafluorobutanesulfonate, triethylammonium nonafluorobutanesulfonate, pyridinium nonafluorobutanesulfonate, triethylammonium camphorsulfonate, camphorsulfone. Pyridinium acid, tetra-n-butylammonium nonafluorobutanesulfonate, tetraphenylammonium nonafluorobutanesulfonate, tetramethylammonium p-toluenesulfonate, diphenyliodonium trifluoromethanesulfonate, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) ) Phenyliodonium, p-toluenesulfonic acid diphenyliodonium, p-to Ensulfonic acid (p-tert-butoxyphenyl) phenyliodonium, trifluoromethanesulfonic acid triphenylsulfonium, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, trifluoromethanesulfonic acid bis (p-tert-butoxyphenyl) Phenylsulfonium, trifluoromethanesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, p-toluenesulfonic acid triphenylsulfonium, p-toluenesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, p-toluenesulfonic acid bis ( p-tert-butoxyphenyl) phenylsulfonium, p-toluenesulfonic acid tris (p-tert-butoxyphenyl) sulfonium Nonafluorobutanesulfonic acid triphenylsulfonium, butanesulfonic acid triphenylsulfonium, trifluoromethanesulfonic acid trimethylsulfonium, p-toluenesulfonic acid trimethylsulfonium, trifluoromethanesulfonic acid cyclohexylmethyl (2-oxocyclohexyl) sulfonium, p-toluenesulfonic acid Cyclohexylmethyl (2-oxocyclohexyl) sulfonium, dimethylphenylsulfonium trifluoromethanesulfonate, dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfonium trifluoromethanesulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate, trinaphthyl trifluoromethanesulfonate Sulfonium, triflu Cyclohexylmethyl (2-oxocyclohexyl) sulfonium olomethanesulfonate, trifluoromethanesulfonate (2-norbornyl) methyl (2-oxocyclohexyl) sulfonium, ethylenebis [methyl (2-oxocyclopentyl) sulfonium trifluoromethanesulfonate], 1 , 2'-naphthylcarbonylmethyltetrahydrothiophenium triflate and the like.

  Diazomethane derivatives include bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (xylenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (cyclopentylsulfonyl) diazomethane, bis (n-butylsulfonyl) diazomethane Bis (isobutylsulfonyl) diazomethane, bis (sec-butylsulfonyl) diazomethane, bis (n-propylsulfonyl) diazomethane, bis (isopropylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, bis (n-amylsulfonyl) diazomethane Bis (isoamylsulfonyl) diazomethane, bis (sec-amylsulfonyl) diazomethane, bis (tert-amylsulfur) Nyl) diazomethane, 1-cyclohexylsulfonyl-1- (tert-butylsulfonyl) diazomethane, 1-cyclohexylsulfonyl-1- (tert-amylsulfonyl) diazomethane, 1-tert-amylsulfonyl-1- (tert-butylsulfonyl) diazomethane Etc.

  Examples of glyoxime derivatives include bis-O- (p-toluenesulfonyl) -α-dimethylglyoxime, bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime, bis-O- (p-toluenesulfonyl)- α-dicyclohexylglyoxime, bis-O- (p-toluenesulfonyl) -2,3-pentanedione glyoxime, bis-O- (p-toluenesulfonyl) -2-methyl-3,4-pentanedione glyoxime, Bis-O- (n-butanesulfonyl) -α-dimethylglyoxime, bis-O- (n-butanesulfonyl) -α-diphenylglyoxime, bis-O- (n-butanesulfonyl) -α-dicyclohexylglyoxime Bis-O- (n-butanesulfonyl) -2,3-pentanedione glyoxime, bis-O- ( -Butanesulfonyl) -2-methyl-3,4-pentanedione glyoxime, bis-O- (methanesulfonyl) -α-dimethylglyoxime, bis-O- (trifluoromethanesulfonyl) -α-dimethylglyoxime, bis -O- (1,1,1-trifluoroethanesulfonyl) -α-dimethylglyoxime, bis-O- (tert-butanesulfonyl) -α-dimethylglyoxime, bis-O- (perfluorooctanesulfonyl)- α-dimethylglyoxime, bis-O- (cyclohexanesulfonyl) -α-dimethylglyoxime, bis-O- (benzenesulfonyl) -α-dimethylglyoxime, bis-O- (p-fluorobenzenesulfonyl) -α- Dimethylglyoxime, bis-O- (p-tert-butylbenzenesulfonyl) α- dimethylglyoxime, bis -O- (xylene sulfonyl)-.alpha.-dimethylglyoxime, bis -O- (camphorsulfonyl)-.alpha.-dimethylglyoxime, and the like.

  Examples of bissulfone derivatives include bisnaphthylsulfonylmethane, bistrifluoromethylsulfonylmethane, bismethylsulfonylmethane, bisethylsulfonylmethane, bispropylsulfonylmethane, bisisopropylsulfonylmethane, bis-p-toluenesulfonylmethane, and bisbenzenesulfonylmethane. Can be mentioned.

  Examples of the β-ketosulfone derivative include 2-cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane and 2-isopropylcarbonyl-2- (p-toluenesulfonyl) propane.

  Examples of the nitrobenzyl sulfonate derivative include 2,6-dinitrobenzyl p-toluenesulfonate and 2,4-dinitrobenzyl p-toluenesulfonate.

  Examples of sulfonic acid ester derivatives include 1,2,3-tris (methanesulfonyloxy) benzene, 1,2,3-tris (trifluoromethanesulfonyloxy) benzene, 1,2,3-tris (p-toluenesulfonyloxy). Examples include benzene.

  Examples of sulfonic acid ester derivatives of N-hydroxyimide compounds include N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester, N-hydroxysuccinimide ethanesulfonic acid ester, N-hydroxysuccinimide 1-propanesulfonic acid. Ester, N-hydroxysuccinimide 2-propanesulfonic acid ester, N-hydroxysuccinimide 1-pentanesulfonic acid ester, N-hydroxysuccinimide 1-octanesulfonic acid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester, N-hydroxysuccinimide p-methoxybenzenesulfonic acid ester, N-hydroxysuccinimide 2-chloroethanesulfonic acid ester N-hydroxysuccinimide benzenesulfonic acid ester, N-hydroxysuccinimide-2,4,6-trimethylbenzenesulfonic acid ester, N-hydroxysuccinimide 1-naphthalenesulfonic acid ester, N-hydroxysuccinimide 2-naphthalenesulfonic acid ester, N- Hydroxy-2-phenylsuccinimide methanesulfonate, N-hydroxymaleimide methanesulfonate, N-hydroxymaleimide ethanesulfonate, N-hydroxy-2-phenylmaleimide methanesulfonate, N-hydroxyglutarimide methanesulfonate Ester, N-hydroxyglutarimide benzenesulfonic acid ester, N-hydroxyphthalimide methanesulfonic acid ester, N-hydro Siphthalimidobenzenesulfonic acid ester, N-hydroxyphthalimide trifluoromethanesulfonic acid ester, N-hydroxyphthalimide p-toluenesulfonic acid ester, N-hydroxynaphthalimide methanesulfonic acid ester, N-hydroxynaphthalimide benzenesulfonic acid ester, N- Hydroxy-5-norbornene-2,3-dicarboximide methanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide trifluoromethanesulfonate, N-hydroxy-5-norbornene-2,3 -Dicarboximide p-toluenesulfonic acid ester

  Preferably, triphenylsulfonium trifluoromethanesulfonate, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, trifluoromethanesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, p-toluenesulfonic acid triphenylsulfonium, p-Toluenesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, p-toluenesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, trifluoromethanesulfonic acid trinaphthylsulfonium, trifluoromethanesulfonic acid cyclohexylmethyl (2-oxo (Cyclohexyl) sulfonium, trifluoromethanesulfonic acid (2-norbornyl) methyl (2-oxocyclohexyl) sulfurate Onium salts such as nium, 1,2'-naphthylcarbonylmethyltetrahydrothiophenium triflate, bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (n-butylsulfonyl) ) Diazomethane derivatives such as diazomethane, bis (isobutylsulfonyl) diazomethane, bis (sec-butylsulfonyl) diazomethane, bis (n-propylsulfonyl) diazomethane, bis (isopropylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, bis- Glyoxime derivatives such as O- (p-toluenesulfonyl) -α-dimethylglyoxime, bis-O- (n-butanesulfonyl) -α-dimethylglyoxime, bis Bissulfone derivatives such as butylsulfonylmethane, N-hydroxysuccinimide methanesulfonate, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide 1-propanesulfonate, N-hydroxysuccinimide 2-propanesulfonate, N-hydroxysuccinimide 1-pentanesulfonic acid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester, N-hydroxynaphthalimide methanesulfonic acid ester, N-hydroxynaphthalimide benzenesulfonic acid ester, etc. Acid ester derivatives are used.

The said acid generator can be used individually by 1 type or in combination of 2 or more types.
The addition amount of the acid generator is preferably 0.1 to 50 parts by weight, and more preferably 0.5 to 40 parts by weight with respect to 100 parts by weight of the base resin. If the amount is less than 0.1 part by weight, the amount of acid generated is small and the crosslinking reaction may be insufficient. If the amount exceeds 50 parts by weight, a mixing phenomenon may occur due to the acid moving to the upper resist.

Furthermore, the lower layer film-forming material of the present invention can be blended with a basic compound for improving storage stability.
As a basic compound, it plays the role of the quencher with respect to an acid in order to prevent the acid which generate | occur | produced in trace amount from the acid generator to advance a crosslinking reaction.

  Examples of such basic compounds include primary, secondary, and tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, and sulfonyl groups. A nitrogen-containing compound having a hydroxyl group, a nitrogen-containing compound having a hydroxyl group, a nitrogen-containing compound having a hydroxyphenyl group, an alcoholic nitrogen-containing compound, an amide derivative, an imide derivative, and the like.

  Specifically, primary aliphatic amines include ammonia, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, pentylamine, tert- Examples include amylamine, cyclopentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, dodecylamine, cetylamine, methylenediamine, ethylenediamine, tetraethylenepentamine and the like.

  Secondary aliphatic amines include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine, dicyclopentylamine, dihexylamine, Examples include dicyclohexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, didodecylamine, dicetylamine, N, N-dimethylmethylenediamine, N, N-dimethylethylenediamine, N, N-dimethyltetraethylenepentamine and the like.

  Tertiary aliphatic amines include trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-sec-butylamine, tripentylamine, tricyclopentylamine, tri Hexylamine, tricyclohexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, tridodecylamine, tricetylamine, N, N, N ′, N′-tetramethylmethylenediamine, N, N, Examples thereof include N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethyltetraethylenepentamine and the like.

  Examples of hybrid amines include dimethylethylamine, methylethylpropylamine, benzylamine, phenethylamine, and benzyldimethylamine.

  Specific examples of aromatic amines and heterocyclic amines include aniline derivatives (eg, aniline, N-methylaniline, N-ethylaniline, N-propylaniline, N, N-dimethylaniline, 2-methylaniline, 3- Methylaniline, 4-methylaniline, ethylaniline, propylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5- Dinitroaniline, N, N-dimethyltoluidine, etc.), diphenyl (p-tolyl) amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, pyrrole derivatives (eg pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4-dim Lupyrrole, 2,5-dimethylpyrrole, N-methylpyrrole, etc.), oxazole derivatives (eg oxazole, isoxazole etc.), thiazole derivatives (eg thiazole, isothiazole etc.), imidazole derivatives (eg imidazole, 4-methylimidazole, 4 -Methyl-2-phenylimidazole, etc.), pyrazole derivatives, furazane derivatives, pyrroline derivatives (eg pyrroline, 2-methyl-1-pyrroline etc.), pyrrolidine derivatives (eg pyrrolidine, N-methylpyrrolidine, pyrrolidinone, N-methylpyrrolidone etc.) ), Imidazoline derivatives, imidazolidine derivatives, pyridine derivatives (eg pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4- (1-butylpentyl) pyridine, dimethyl) Lysine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone, 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2- (1-ethylpropyl) pyridine, aminopyridine, dimethylaminopyridine, etc.), pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives, pyrazoline derivatives, pyrazolidine derivatives, piperidine Derivatives, piperazine derivatives, morpholine derivatives, indole derivatives, isoindole derivatives, 1H-indazole derivatives, indoline derivatives, quinoline derivatives (eg quinoline, 3-quinoline carbo Nitriles), isoquinoline derivatives, cinnoline derivatives, quinazoline derivatives, quinoxaline derivatives, phthalazine derivatives, purine derivatives, pteridine derivatives, carbazole derivatives, phenanthridine derivatives, acridine derivatives, phenazine derivatives, 1,10-phenanthroline derivatives, adenine derivatives, adenosine Examples include derivatives, guanine derivatives, guanosine derivatives, uracil derivatives, uridine derivatives and the like.

  Furthermore, examples of the nitrogen-containing compound having a carboxy group include aminobenzoic acid, indolecarboxylic acid, amino acid derivatives (for example, nicotinic acid, alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, glycylleucine, leucine, methionine. , Phenylalanine, threonine, lysine, 3-aminopyrazine-2-carboxylic acid, methoxyalanine) and the like.

  Examples of the nitrogen-containing compound having a sulfonyl group include 3-pyridinesulfonic acid and pyridinium p-toluenesulfonate.

  As a nitrogen-containing compound having a hydroxyl group, a nitrogen-containing compound having a hydroxyphenyl group, and an alcoholic nitrogen-containing compound, 2-hydroxypyridine, aminocresol, 2,4-quinolinediol, 3-indolemethanol hydrate, monoethanolamine, Diethanolamine, triethanolamine, N-ethyldiethanolamine, N, N-diethylethanolamine, triisopropanolamine, 2,2'-iminodiethanol, 2-aminoethanol, 3-amino-1-propanol, 4-amino-1 -Butanol, 4- (2-hydroxyethyl) morpholine, 2- (2-hydroxyethyl) pyridine, 1- (2-hydroxyethyl) piperazine, 1- [2- (2-hydroxyethoxy) ethyl] piperazine, piperidine ethanol 1- (2-hydroxyethyl) pyrrolidine, 1- (2-hydroxyethyl) -2-pyrrolidinone, 3-piperidino-1,2-propanediol, 3-pyrrolidino-1,2-propanediol, 8-hydroxyurolo Lysine, 3-cuincridinol, 3-tropanol, 1-methyl-2-pyrrolidine ethanol, 1-aziridine ethanol, N- (2-hydroxyethyl) phthalimide, N- (2-hydroxyethyl) isonicotinamide, etc. Illustrated.

  Examples of amide derivatives include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide and the like. Examples of imide derivatives include phthalimide, succinimide, maleimide and the like.

  The compounding amount of the basic compound is preferably 0.001 to 2 parts by weight, particularly 0.01 to 1 part by weight based on 100 parts by weight of the total base resin. If the blending amount is less than 0.001 part by weight, the blending effect may not be obtained. If the blending amount exceeds 2 parts by weight, all of the acid generated by heat may be trapped and may not be crosslinked.

  The organic solvent that can be used in the lower layer film-forming material of the present invention is not particularly limited as long as the base resin, the acid generator, the cross-linking agent, and other additives can be dissolved. Specific examples thereof include ketones such as cyclohexanone and methyl-2-amyl ketone; 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol and the like. Alcohols: ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl 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, lactic acid Ethyl, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate , Tert-butyl acetate, tert-butyl propionate, propylene glycol monomethyl ether acetate, propylene glycol mono tert-butyl ether acetate and the like, and one or more of these can be used in combination. It is not limited. In the present invention, among these organic solvents, diethylene glycol dimethyl ether, 1-ethoxy-2-propanol, ethyl lactate, propylene glycol monomethyl ether acetate and mixed solvents thereof are preferably used.

  The blending amount of the solvent is preferably 200 to 10,000 parts by weight, particularly preferably 300 to 5,000 parts by weight with respect to 100 parts by weight of the total base resin.

  The present invention includes a step of forming a lower layer film on a substrate using the photoresist lower layer film forming material, a step of forming a photoresist film using a photoresist composition on the lower layer film, and the photoresist. A step of exposing a pattern circuit region of the film, a step of developing with a developing solution thereafter to form a resist pattern on the photoresist film, and the lower layer film and the photoresist film on which the resist pattern is formed as a mask There is provided a pattern forming method comprising the step of etching the substrate.

  The present invention also includes a step of forming a lower layer film on a substrate using a photoresist film forming material, a step of forming a photoresist film using a photoresist composition on the lower layer film, and the photoresist. A step of exposing a pattern circuit region of the film; a step of developing with a developer thereafter to form a resist pattern on the photoresist film; and a step of forming the lower layer film using the photoresist film on which the resist pattern is formed as a mask. There is provided a pattern forming method including an etching step and a step of forming a pattern on the substrate by etching the substrate using a lower layer film on which a pattern is formed as a mask.

These pattern forming methods will be described with reference to FIG.
The lower layer film 10 of the present invention can be formed on a substrate to be processed by a spin coat method or the like, similar to a photoresist. After spin coating, it is desirable to evaporate the solvent and bake to accelerate the crosslinking reaction in order to prevent mixing with the upper layer resist. The baking temperature is preferably in the range of 80 to 300 ° C. and in the range of 10 to 300 seconds. Although the thickness of this lower layer film is appropriately selected, it is preferably 100 to 20,000 nm, particularly 150 to 15,000 nm. After producing the lower layer film, a photoresist film 11 is produced thereon.

  As a photoresist composition for forming this resist layer, a well-known thing can be used. From the point of resistance to oxygen gas etching, preferably, a positive type containing a silicon atom-containing polymer such as a polysilsesquioxane derivative or a vinylsilane derivative as a base polymer, and further containing an organic solvent, an acid generator, and a basic compound as necessary. The photoresist composition is used. The polysilsesquioxane derivative is preferably a silsesquioxane having a ladder skeleton repeating unit pendant of a carboxylate substituted with an acid labile group, and the vinylsilane derivative is preferably (a ) Vinyl silane, (b) maleic anhydride, (c) methacrylate substituted with acid labile groups, acrylate substituted with acid labile groups and norbornyl carboxylate substituted with acid labile groups A terpolymer with one selected from a group. As a silicon atom containing polymer, it is not limited to this, The well-known polymer used for this kind of resist composition can be used. The type and amount of the organic solvent, acid generator, and basic compound used in the resist composition are, for example, the organic solvent that is (B) of the lower layer film forming material, the acid generator that is (D) component, and the basic compound. It is the same. Moreover, the addition amount of the base resin in the resist composition is, for example, the same as the addition amount of the polymer of the general formula (1) that is the component (A) of the lower layer film forming material.

  When forming the resist film 11 with the said photoresist composition, a spin coat method is used preferably similarly to the case where the lower layer film 10 is formed. Pre-baking is performed after spin-coating the resist, and a range of 10 to 300 seconds at 80 to 180 ° C. is preferable. Thereafter, exposure is performed according to a conventional method, post-exposure baking (PEB), and development is performed to obtain a resist pattern (FIG. 1A). The thickness of the resist film is not particularly limited, but is preferably 30 to 500 nm, particularly 50 to 400 nm.

Next, using the obtained resist pattern as a mask, dry etching is preferably performed, more preferably etching mainly using oxygen gas. This etching can be performed by a conventional method. At this time, in addition to the oxygen gas, an inert gas such as He or Ar, or CO, CO ₂ , NH ₃ , SO ₂ , N ₂ , or NO ₂ gas can be added. In particular, the latter gas is used for side wall protection for preventing undercut of the pattern side wall.

The next substrate 12 can be etched by a conventional method, preferably dry etching. For example, if the substrate 12a to be processed on the base substrate 12b is SiO ₂ or SiN, etching mainly using a fluorocarbon gas, p- For Si, Al, and W, etching is performed mainly using a chlorine-based or bromine-based gas. The pattern pattern after the substrate dry etching is shown in FIG. The underlayer film of the present invention is characterized by excellent etching resistance of the substrate to be processed 12a.

The substrate to be processed 12a is formed on the base substrate 12b.
There is no particular limitation on the substrate, and Si, α-Si, p-Si, SiO ₂ , SiN, SiON, W, TiN, Al, etc. may be made of a material different from the film to be processed (substrate to be processed). Used. Various low-k films such as Si, SiO ₂ , SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si, and their stopper films are used as the work film. Usually, it can be formed to a thickness of 50 to 10,000 nm, particularly 100 to 5,000 nm.

EXAMPLES Hereinafter, although a synthesis example, a polymerization example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited by these description.
Synthesis example 1
In a 300 mL flask, 120 g of poly-p-hydroxystyrene having a weight average molecular weight (Mw) of 14000 and a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 1.67 and 41 g of 9-anthracenemethanol are dissolved in a THF solvent. Then, 0.5 g of tosylic acid was added, and the mixture was stirred at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 155 g of Polymer 1.
The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, the ratio of anthracene methyl groups in the polymer was determined by ¹ H-NMR analysis, and the following results were obtained.
Copolymerization composition ratio p-hydroxy-m-anthracenemethylstyrene: p-hydroxystyrene (molar ratio) = 0.20: 0.80,
Weight average molecular weight (Mw) = 15,000
The molecular weight distribution (Mw / Mn) = 1.70.

Synthesis example 2
To a 500 mL flask, 80 g of 4-hydroxystyrene, 45 g of methyl 2,5-norbornadiene-2-carboxylate, and 40 g of toluene as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen flow were repeated three times. After raising the temperature to room temperature, 4.1 g of AIBN was added as a polymerization initiator, and the temperature was raised to 80 ° C. and reacted for 24 hours. This reaction solution was concentrated to 1/2, precipitated in a mixed solution of 300 mL of methanol and 50 mL of water, and the obtained white solid was filtered and dried under reduced pressure at 60 ° C. to obtain 98 g of a white polymer.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio 4-hydroxystyrene: methyl 2,5-norbornadiene-2-carboxylate = 0.67: 0.33
Weight average molecular weight (Mw) = 8120
Molecular weight distribution (Mw / Mn) = 1.96
Next, 98 g of poly-4-hydroxystyrene-2,5-norbornadiene-2-carboxylate and 33 g of 9-anthracenemethanol obtained by the above method were dissolved in a THF solvent in a 300 mL flask, and 0.5 g of tosylic acid was added. In addition, the mixture was stirred at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 124 g of polymer 2.
When the ¹ H-NMR and GPC measurement of the obtained polymer was carried out, the following analysis results were obtained.
Copolymerization composition ratio p-hydroxy-m-anthracene methylstyrene: 4-hydroxystyrene: methyl 2,5-norbornadiene-2-carboxylate = 0.23: 0.37: 0.33
Weight average molecular weight (Mw) = 9100
Molecular weight distribution (Mw / Mn) = 1.88

Synthesis example 3
In a 300 mL flask, 98 g of methyl poly-4-hydroxystyrene-2,5-norbornadiene-2-carboxylate and 78 g of 1-adamantane methanol were dissolved in a THF solvent, 0.5 g of tosylic acid was added, and the mixture was stirred at 80 ° C. for 24 hours. I let you. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 124 g of Polymer 3.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio p-hydroxy-m-adamantane methylstyrene: 4-hydroxystyrene: methyl 2,5-norbornadiene-2-carboxylate = 0.58: 0.09: 0.33
Weight average molecular weight (Mw) = 9200
Molecular weight distribution (Mw / Mn) = 1.86

Synthesis example 4
In a 300 mL flask, 114 g of poly-4-hydroxystyrene in which 20 mol% of a weight average molecular weight (Mw) of 13300 and a molecular weight distribution (Mw / Mn) of 1.55 was hydrogenated and 78 g of 1-adamantane methanol were dissolved in a THF solvent. Then, 0.5 g of tosylic acid was added, and the mixture was stirred at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 153 g of polymer 4.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio p-hydroxy-m-adamantane methylstyrene: 4-hydroxystyrene: hydrogenated 4-hydroxystyrene = 0.85: 0.15: 0.20
Weight average molecular weight (Mw) = 14300
Molecular weight distribution (Mw / Mn) = 1.56

Synthesis example 5
To a 500 mL flask, 80 g of 4-hydroxystyrene, 64 g of 2-acrylic acid-1-adamantane, and 40 g of toluene as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen flow were repeated three times. After raising the temperature to room temperature, 4.1 g of AIBN was added as a polymerization initiator, and the temperature was raised to 80 ° C. and reacted for 24 hours. This reaction solution was concentrated to 1/2, precipitated in a mixed solution of 300 mL of methanol and 50 mL of water, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain 134 g of a white polymer.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio 4-hydroxystyrene: 2-acrylic acid-1-adamantane = 0.69: 0.31
Weight average molecular weight (Mw) = 11600
Molecular weight distribution (Mw / Mn) = 1.71
Next, 134 g of poly-hydroxystyrene-2-acrylic acid-1-adamantane and 88 g of 1-adamantane methanol obtained by the above method were dissolved in a THF solvent in a 300 mL flask, 0.5 g of tosylic acid was added, and the mixture was stirred at 80 ° C. for 24 hours. Stir for hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 178 g of polymer 5.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio p-hydroxy-m-adamantane methylstyrene: 4-hydroxystyrene: 2-acrylic acid-1-adamantane = 0.53: 0.18: 0.32
Weight average molecular weight (Mw) = 12900
Molecular weight distribution (Mw / Mn) = 1.68

Synthesis Example 6
To a 500 mL flask, 80 g of 4-hydroxystyrene, 68 g of vinylnaphthalene, and 40 g of toluene as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen flow were repeated three times. After raising the temperature to room temperature, 4.1 g of AIBN was added as a polymerization initiator, and the temperature was raised to 80 ° C. and reacted for 24 hours. This reaction solution was concentrated to 1/2, precipitated in a mixed solution of 300 mL of methanol and 50 mL of water, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain 139 g of a white polymer.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio 4-hydroxystyrene: vinylnaphthalene = 0.52: 0.48
Weight average molecular weight (Mw) = 10900
Molecular weight distribution (Mw / Mn) = 1.71
In a 500 mL flask, 120 g of the above poly-4-hydroxystyrene-vinylnaphthalene and 88 g of 1-adamantane methanol were dissolved in a THF solvent, 0.5 g of tosylic acid was added, and the mixture was stirred at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 188 g of polymer 6.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio p-hydroxy-m-adamantane methylstyrene: 4-hydroxystyrene: vinylnaphthalene = 0.44: 0.08: 0.48
Weight average molecular weight (Mw) = 15,100
Molecular weight distribution (Mw / Mn) = 1.68

Synthesis example 7
In a 300 mL flask, 120 g of poly-p-hydroxystyrene having Mw 14000 and Mw / Mn 1.67 and 62 g of 1-pyrenemethanol were dissolved in a THF solvent, 0.5 g of tosylic acid was added, and the mixture was stirred at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 166 g of polymer 7.
When molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the ratio of anthracene methyl groups in the polymer was determined by ¹ H-NMR analysis, the following results were obtained.
Copolymerization composition ratio p-hydroxy-m-pyrenemethylstyrene: p-hydroxystyrene (molar ratio) = 0.23: 0.77
Weight average molecular weight (Mw) = 15,900
Molecular weight distribution (Mw / Mn) = 1.70

Synthesis example 8
In a 300 mL flask, 120 g of poly-p-hydroxystyrene-co-indene 70:30 having Mw 8,000 and Mw / Mn 2.01 and 41 g of 9-anthracenemethanol were dissolved in THF solvent, 0.5 g of tosylic acid was added, Stir at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 153 g of polymer 8. It should be noted that the expression “poly-monomer 1-co-monomer 2” represents a copolymer comprising monomers 1 and 2.
The molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the ratio of anthracene methyl groups in the polymer was determined by ¹ H-NMR analysis as follows.
Polymer 1; p-hydroxy-m-anthracenemethylstyrene: p-hydroxystyrene: indene (molar ratio) = 0.20: 0.50: 0.3 Mw8,800, Mw / Mn2.06

Synthesis Example 9
In a 300 mL flask, 120 g of poly-p-hydroxystyrene-co-acenaphthylene 70:30 having Mw 7,000 and Mw / Mn 2.11 and 41 g of 9-anthracenemethanol were dissolved in THF solvent, 0.5 g of tosylic acid was added, Stir at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 156 g of polymer 9.
The molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the ratio of anthracene methyl groups in the polymer was determined by ¹ H-NMR analysis as follows.
Polymer 1; p-hydroxy-m-anthracene methylstyrene: p-hydroxystyrene: acenaphthylene (molar ratio) = 0.20: 0.50: 0.3 Mw 7,900, Mw / Mn 2.13

Synthesis Example 10
Dissolve 120 g of poly-p-hydroxystyrene-co-2,5-norbornadiene-2-carboxylate 70:30 with Mw 7,600 and Mw / Mn 2.05 in a 300 mL flask and 41 g of 9-anthracenemethanol in THF solvent. And 0.5 g of tosylic acid was added and allowed to stir at 80 ° C. for 24 hours. The catalyst and metal impurities were removed by washing with water, and THF was removed under reduced pressure to obtain 151 g of polymer 10.
The molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the ratio of anthracene methyl groups in the polymer was determined by ¹ H-NMR analysis as follows.
Polymer 1; p-hydroxy-m-anthracene methylstyrene: p-hydroxystyrene: methyl 2,5-norbornadiene-2-carboxylate (molar ratio) = 0.20: 0.50: 0.3 Mw8,500, Mw / Mn 2.16

Comparative Synthesis Example 1
To a 500 mL flask, 96 g of 4-hydroxystyrene, 55 g of 2-methacrylic acid-1-anthracenemethyl, and 40 g of toluene as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen flow were repeated three times. After raising the temperature to room temperature, 4.1 g of AIBN was added as a polymerization initiator, and the temperature was raised to 80 ° C. and reacted for 24 hours. This reaction solution was concentrated to 1/2, precipitated in a mixed solution of 300 mL of methanol and 50 mL of water, and the resulting white solid was filtered and dried under reduced pressure at 60 ° C. to obtain 140 g of a white polymer.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio 4-hydroxystyrene: 2-methacrylic acid-1-anthracenemethyl = 79: 21
Weight average molecular weight (Mw) = 13200
Molecular weight distribution (Mw / Mn) = 1.75

Comparative Synthesis Example 2
To a 500 mL flask, 40 g of 4-hydroxystyrene, 160 g of 2-methacrylic acid-1-adamantane, and 40 g of toluene as a solvent were added. The reaction vessel was cooled to −70 ° C. in a nitrogen atmosphere, and vacuum degassing and nitrogen flow were repeated three times. After raising the temperature to room temperature, 4.1 g of AIBN was added as a polymerization initiator, and the temperature was raised to 80 ° C. and reacted for 24 hours. This reaction solution was concentrated to 1/2, precipitated in a mixed solution of 300 mL of methanol and 50 mL of water, and the obtained white solid was filtered and dried under reduced pressure at 60 ° C. to obtain 188 g of a white polymer.
When the obtained polymer was measured by ¹ H-NMR and GPC, the following analysis results were obtained.
Copolymerization composition ratio 4-hydroxystyrene: 2-methacrylic acid-1-adamantane = 0.32: 0.68
Weight average molecular weight (Mw) = 10900
Molecular weight distribution (Mw / Mn) = 1.77

Examples, Comparative Examples Resins represented by polymers 1 to 10, resins represented by comparative examples 1 and 2, polymers for silicon-containing intermediate layers, acid generators represented by AG1 and 2, and crosslinking agents represented by CR1 and 2. , FC-430 (manufactured by Sumitomo 3M) dissolved in a solvent containing 0.1% by weight at a ratio shown in Table 1, and filtered through a filter made of 0.1 μm fluororesin to form a lower layer membrane solution and an intermediate layer membrane Each solution was prepared.
A solution of a lower layer film forming material and a solution of an intermediate layer film solution are applied on a silicon substrate and baked at 200 ° C. for 60 seconds to form a lower layer film having a thickness of 500 nm (hereinafter abbreviated as UDL 1 to 11). A silicon-containing film having a thickness of 100 nm is formed (hereinafter abbreviated as SOG 1 and 2). A. Refractive indexes (n, k) of UDL 1 to 11 and SOG 1 and 2 at wavelengths of 248 nm, 193 nm, and 157 nm were obtained using a spectroscopic ellipsometer with variable incident angle (VASE) manufactured by Woollam, and the results are shown in Table 1.

The lower layer film forming material solution (UDL-1, 2, 7, 8) was applied on a 300 nm thick SiO ₂ substrate and baked at 200 ° C. for 60 seconds to form a lower layer film having a thickness of 500 nm. A KrF silicon-containing resist solution 1 having a composition shown in Table 2 and comprising a KrF silicon-containing polymer 1, an acid generator PAG1, a base additive TMMEA, and a solvent was prepared. This resist solution was applied onto the lower layer films UDL-1, 2, and 7 and baked at 120 ° C. for 60 seconds to form a silicon-containing resist film layer having a thickness of 200 nm. Next, exposure was performed with a KrF exposure apparatus (Nikon Corp .; S203B, NA 0.68, σ0.75, 2/3 ring illumination, Cr mask), baked at 130 ° C. for 90 seconds (PEB), and 2.38 wt%. Development was performed with an aqueous tetramethylammonium hydroxide (TMAH) solution for 60 seconds to obtain a positive pattern. Observing the pattern shape of 0.15 μmL / S of the obtained pattern, as shown in Table 3, there is no skirting, undercut, or intermixing phenomenon near the substrate, and a rectangular pattern is obtained It was confirmed.
The lower layer film-forming material solution (UDL-3, 4, 5, 6) was applied onto a 300 nm thick SiO ₂ substrate and baked at 200 ° C. for 60 seconds to form a lower film having a thickness of 500 nm. ArF silicon-containing resist solutions 1 and 2 comprising ArF silicon-containing polymers 1 and 2, acid generator PAG1, base additive TAEA, and solvent having the composition shown in Table 2 were prepared. This resist solution was applied onto the lower layers UDL-3, 4, 5, and 6 and baked at 110 ° C. for 60 seconds to form a 200-nm-thick silicon-containing resist film layer. Next, the film was exposed with an ArF exposure apparatus (Nikon Corp .; S305B, NA 0.68, σ 0.85, 2/3 ring illumination, Cr mask), baked at 110 ° C. for 90 seconds (PEB), and 2.38 wt%. Development was performed with an aqueous tetramethylammonium hydroxide (TMAH) solution for 60 seconds to obtain a positive pattern. Observe the pattern shape of 0.12 μmL / S of the obtained pattern, and as shown in Table 3, there is no skirting, undercut, or intermixing phenomenon near the substrate, and a rectangular pattern is obtained It was confirmed.
A lower layer film-forming material solution (UDL-8) was applied onto a 300 nm thick SiO ₂ substrate and baked at 200 ° C. for 60 seconds to form a lower film having a thickness of 500 nm. A silicon-containing intermediate layer material solution SOG1 was applied thereon and baked at 200 ° C. for 60 seconds to form an intermediate layer having a thickness of 100 nm. A KrF resist 5 solution having the composition shown in Table 2 was prepared. This resist solution was applied onto the intermediate layer SOG1 and baked at 120 ° C. for 60 seconds to form a single-layer resist film layer having a thickness of 200 nm. Next, exposure was performed with a KrF exposure apparatus (Nikon Corp .; S203B, NA 0.68, σ0.75, 2/3 ring illumination, Cr mask), baked at 120 ° C. for 90 seconds (PEB), and 2.38 wt%. Development was performed with an aqueous tetramethylammonium hydroxide (TMAH) solution for 60 seconds to obtain a positive pattern. Observing the pattern shape of 0.15 μmL / S of the obtained pattern, as shown in Table 3, there is no skirting, undercut, or intermixing phenomenon near the substrate, and a rectangular pattern is obtained It was confirmed.
The lower layer film forming material solution (UDL-9, 10) was applied onto a 300 nm thick SiO ₂ substrate and baked at 200 ° C. for 60 seconds to form a lower layer film having a thickness of 500 nm. A silicon-containing intermediate layer material solution SOG2 was applied thereon and baked at 200 ° C. for 60 seconds to form an intermediate layer having a thickness of 100 nm. An ArF resist 6 solution having the composition shown in Table 2 was prepared. This resist solution was applied onto the intermediate layer SOG1 and baked at 120 ° C. for 60 seconds to form a single-layer resist film layer having a thickness of 200 nm. Next, the film was exposed with an ArF exposure apparatus (Nikon Corp .; S305B, NA 0.68, σ 0.85, 2/3 ring illumination, Cr mask), baked at 120 ° C. for 90 seconds (PEB), and 2.38% by weight. Development was performed with an aqueous tetramethylammonium hydroxide (TMAH) solution for 60 seconds to obtain a positive pattern. Observe the pattern shape of 0.25 μmL / S of the obtained pattern, and as shown in Table 3, there is no skirting, undercut, or intermixing phenomenon near the substrate, and a rectangular pattern is obtained It was confirmed.

Next, a dry etching resistance test was performed. First, the same lower layer films (UDL1 to 11) used for the refractive index measurement were prepared, and these lower layer films were tested under the following conditions (1) as an etching test with a CHF ₃ / CF ₄ gas. In this case, the difference in film thickness between the lower layer film and the resist before and after etching was measured using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited. The results are shown in Table 4.
(1) Etching test with CHF ₃ / CF ₄ gas Etching conditions are as shown below.
Chamber pressure 40.0Pa
RF power 1,300W
Gap 9mm
CHF ₃ gas flow rate 30ml / min
CF ₄ gas flow rate 30ml / min
Ar gas flow rate 100ml / min
60 sec

Further, an etching test using a Cl ₂ / BCl ₃ gas was performed using the lower layer films (UDL 1 to 11) under the following condition (2). In this case, the thickness difference of the polymer film before and after etching was determined using a dry etching apparatus L-507D-L manufactured by Nidec Anelva Corporation. The results are shown in Table 5.
(2) Etching test with Cl ₂ / BCl ₃ gas Etching conditions are as shown below.
Chamber pressure 40.0Pa
RF power 300W
Gap 9mm
Cl ₂ gas flow rate 30ml / min
BCl ₃ gas flow rate 30ml / min
CHF ₃ gas flow rate 100ml / min
O ₂ gas flow rate 2ml / min
60 sec

On the other hand, a silicon-containing resist having a 0.10 μmL / S pattern obtained after the ArF exposure and development was etched with oxygen gas.
Etching conditions are as shown below.
Chamber pressure 450mTorr
RF power 600W
Ar gas flow rate 40sccm
O ₂ gas flow rate 60sccm
Gap 9mm
Time 20sec

Next, etching with a CHF ₃ / CF ₄ gas was performed under the conditions shown in (1) to process the SiO ₂ substrate.
After development, a two-layer process, after the oxygen gas etching, the cross section of the pattern after CHF ₃ / CF ₄ based gas etching of the substrate processing, three-layer case of the process, CF ₄ based processing of silicon-containing intermediate layer After gas etching and oxygen gas etching for lower layer processing, pattern cross sections after substrate processing CHF ₃ / CF ₄ gas etching were observed with an electron microscope (S-4700) manufactured by Hitachi, Ltd., and the shapes were compared. The results are summarized in Table 6. After development, the cross-sectional shape of the silicon-containing resist was observed, and the cross-sectional shape of the lower layer film was observed after oxygen etching and after CHF ₃ / CF ₄ etching.

As shown in Table 1, the n value of the refractive index of the lower layer film of the present invention is 1.5 to 1.9 and the k value is in the range of 0.15 to 0.4, which is a film thickness of 200 nm or more. Optimum refractive index (n) and extinction coefficient (k) sufficient to exhibit a sufficient antireflection effect, and as shown in Tables 5 and 6, CF ₄ / CHF ₃ gas and Cl ₂ / BCl ₃ gas The etching rate is similar to that of the novolak resin, and the etching rate is lower than that of polyhydroxystyrene / hydroxyethyl acrylate copolymer, and the etching resistance is high. Further, as shown in Tables 3 and 4, it was confirmed that the resist shape after development, the shape of the lower layer film after the oxygen etching, and the substrate processing etching were also good.

It is description regarding the pattern formation method of this invention, (a) The resist pattern after image development, (b) The pattern after board | substrate dry etching is shown. It is a graph which shows the relationship between the film thickness of an antireflection film, and a reflectance. It is a graph which shows the relationship between the film thickness of a lower layer film, and the reflectance which changed n value in the range of 1.0-2.0, with lower layer film refractive index k value being fixed to 0.3. It is a graph which shows the relationship between the film thickness of a lower layer film, and the reflectance which changed n value in the range of 0.1-1.0, with lower layer film refractive index n value being fixed to 1.5.

Explanation of symbols

10 Underlayer Film 11 Photoresist Film 12 Substrate 12a Substrate 12b Substrate Substrate

Claims (8)

A material for forming a lower layer film of a photoresist layer, which contains a polymer comprising a repeating unit represented by the following general formula (1).

(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a hydroxy group-containing alkyl group having 1 to 10 carbon atoms, or 1 to 1 carbon atom. 10 represents an acyl group or a glycidyl group, and R ³ is a monovalent organic group represented by the general formula (2), wherein R ⁴ represents an alkylene group having 1 to ⁴ carbon atoms. , R ⁵ represents a ring-shaped alkyl group or an aryl group having 6 to 20 carbon atoms having 4 to 20 carbon atoms, hydroxy groups, optionally .m also contain ether groups or ester groups is 1 or 2, n is 1 or 2)
The material for forming an underlayer film according to claim 1, wherein the polymer further comprises a repeating unit selected from the following general formulas (4) to (6).

(In the general formulas (4) to (6), R ⁶ and R ⁷ independently represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. , R ⁸ represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a hydroxy group, or an alkoxycarbonyl group, X represents a methylene group, an oxygen atom, or a sulfur atom, p And q are each independently 0 or an integer of 1 to 4.)   Furthermore, the lower layer film forming material of Claim 1 or Claim 2 containing an organic solvent and an acid generator.   Furthermore, the lower layer film forming material in any one of Claims 1-3 containing a crosslinking agent.   A step of forming a lower layer film on a substrate using the material according to any one of claims 1 to 4, a step of forming a photoresist film using a photoresist composition on the lower layer film, and the photo A step of exposing a pattern circuit region of the resist film, a step of developing with a developing solution to form a resist pattern on the photoresist film, and a lower layer film using the photoresist film on which the resist pattern is formed as a mask And a pattern forming method comprising the step of etching the substrate.   A step of forming a lower layer film on a substrate using the material according to any one of claims 1 to 4, a step of forming a photoresist film using a photoresist composition on the lower layer film, and the photo A step of exposing a pattern circuit region of the resist film, a step of developing with a developing solution to form a resist pattern on the photoresist film, and a lower layer film using the photoresist film on which the resist pattern is formed as a mask And a step of etching the substrate using the lower layer film on which the pattern is formed as a mask to form a pattern on the substrate.   The pattern forming method according to claim 5, wherein the photoresist composition comprises a silicon atom-containing polymer.   The pattern forming method according to claim 6, wherein the step of etching the lower layer film using the photoresist film as a mask includes oxygen gas etching, and the step of forming a pattern using the lower layer film as a mask includes dry etching. .

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