TW201026754A - Composition for forming sidewall - Google Patents

Abstract

A composition for forming a side wall, which is suitable for forming a side wall in contact with a photoresist pattern. Specifically disclosed is a composition for forming a side wall for lithography, which contains a silicon-containing polymer, which has a silanol group at an end while containing structural units represented by formula (1a) and formula (1b) (wherein R3 represents an organic group), and a solvent mainly composed of a specific organic solvent. Also specifically disclosed is a composition for forming a side wall for lithography, which contains a silicon-containing polymer, which has a silanol group or alternatively a silanol group and a hydrogen atom at an end while containing at least one structural unit represented by formula (2) and/or formula (3) (wherein R2 and R1 each represents an organic group), and a solvent mainly composed of a specific organic solvent.

Description

201026754 VI. Description of the Invention: [Technical Field] The present invention relates to a lithography technique used in the process of a semiconductor device, and is used to contact a photoresist pattern to form a composition of a sidewall. [Prior Art] In recent years, with the high integration of semiconductor elements, it is required to refine the pattern of wiring φ or the like. In order to form a fine pattern, the light source for exposure uses a short-wavelength light such as an ArF excimer laser (having a wavelength of about 193 nm) to form a photoresist pattern. The larger the aspect ratio (height/width) of the photoresist pattern, the easier it is to produce pattern dumping. In order to prevent the pattern from falling over, it is necessary to thin the film thickness of the photoresist. However, when the film to be processed is dry-etched using the photoresist pattern as a mask, the photoresist pattern formed by the photoresist having a small film thickness disappears. Therefore, in recent years, as a method of forming a fine pattern, various lithography processes called φ double pattern forming method or double exposure method have been examined. One of its known methods is the so-called sidewall method. The side wall is known to be formed by using a ruthenium oxide film formed by a CVD apparatus, but a film formed by a coating solution may be used instead of the film formed by the CVD apparatus. Patent Documents 1 to 4 propose a method of forming a sidewall having a specific width on a side surface of a resist pattern and then removing the photoresist pattern, thereby forming a fine pattern formed by the sidewall. The side walls described in these prior documents are formed by coating a composition comprising a ruthenium-containing polymer and an organic solvent on a photoresist pattern-5-201026754 to form a ruthenium-containing polymerization. a layer of a layer, followed by exposure and baking to form a crosslinked bonding layer at the interface between the photoresist pattern and the germanium-containing polymer layer, and then removing the germanium-containing polymer layer without forming a cross-linking bond, and The uranium is returned to the crosslinked bonding layer to expose the upper portion of the photoresist pattern. In the above-mentioned prior art, it is described that the above-mentioned ruthenium-containing polymer has an epoxy group as an action group capable of forming a cross-linking bond, and exemplifies a polysiloxane compound or a polysesquioxane compound as the aforementioned ruthenium-containing compound. Polymer. However, in these prior documents, the specific structural unit of the aforementioned polyoxyalkylene@ compound or the aforementioned polysilsesquioxane compound is not explicitly or proposed, and further, the aforementioned polyoxyalkylene compound or the aforementioned polysulfide oxide Since the alkane compound contains an oxygen atom in addition to a ruthenium atom in the main chain, when the polyoxy siloxane compound or the polysilsesquioxane compound has an epoxy group, the ruthenium content of the ruthenium-containing polymer is increased. It is even more unfavorable. Further, in the above-mentioned prior art, it is described that when the content of the ruthenium molecule is 40% by weight or more based on the total weight of the polymer, it is difficult to uniformly apply the ruthenium-containing polymer layer to the photoresist pattern. . However, for the improvement of 涂布 coatability, no investigation was made except for adjusting the yttrium content. Patent Document 1: Japanese Laid-Open Patent Publication No. Hei. No. 2008-72097. Patent Document 3: U.S. Patent Application Publication No. 2008/006421 No. 3 Patent Document 4: U.S. Patent Application Publication The invention is based on the above-mentioned circumstances, and the object to be solved is to provide an object even if it contains bismuth. The polymer does not have an epoxy group as an action group capable of forming a cross-linking bond, and can also remarkably improve the coating property with respect to the substrate on which the photoresist pattern is formed and the coating property with respect to the photoresist pattern φ type. And a composition for forming a side wall which is less mixed with the photoresist pattern. In addition, the surface of the photoresist underlayer film and the side surface of the photoresist pattern are provided without voids, and the dry etching rate with respect to the oxygen-based gas is small, and the dry etching rate with respect to the fluorine-based gas is large. The side walls formed by the composition. (Means for Solving the Problem) The inventors of the present invention have carefully studied the above problems in order to solve the above problems. In other words, the first aspect of the present invention is a composition for forming a side wall for a lithography technique, comprising: a polymer containing ruthenium and a solvent containing a specific organic solvent as a main component; and the polymerization containing ruthenium And having a sterol group ' at its end and having the structural unit represented by the following formula (la) and formula (lb); [Chemical Formula 1] R3 (1b) - (-βιΌ-ι.δ^—(1a) -^-Si〇2.〇*)~ 201026754 (wherein R3 represents a methyl group, an ethyl group or a phenyl group). The above formula (la) is a structural unit in which one atomic group and three oxygen atoms are bonded to each of the ruthenium atoms. On the other hand, the above formula (lb) is represented by a structural unit in which each of the ruthenium atoms is bonded with four oxygen atoms. When the raw material monomer does not use a 4-functional decane compound typified by tetraethoxy decane, it does not have the structural unit represented by the above formula (lb). The ruthenium-containing polymer described in the present specification is not limited to a polymer, and includes an oligomer. Therefore, the above ruthenium-containing polymer may be a polymer or an oligomer. The second aspect of the present invention is a composition for forming a side wall for a lithography technique, comprising: a polymer containing ruthenium and a solvent containing a specific organic solvent as a main component; and the ruthenium-containing polymer is The terminal has a sterol group or the sterol group and a hydrogen atom, and has at least one of the structural units represented by the following formula (2) and/or the following formula (3);

(In the formula, R2 each independently represents a methyl group, an ethyl group or a phenyl group, and R1 represents a hydrogen atom, a methyl group, an ethyl group, an OH group or a phenyl group). Advantageous Effects of Invention The composition for forming a side wall of the present invention is excellent in coatability with respect to a substrate on which a resist pattern is formed, and coating property with respect to the resist pattern is -8 - 201026754. Therefore, the composition for forming a side wall of the present invention can be applied by easily applying a photoresist pattern by a spin coating method. Further, the side wall formed by the side wall forming composition of the present invention is excellent in dry uranium engraving characteristics with respect to a fluorine-based gas and an oxygen-based gas. Further, in the side wall forming composition of the present invention, even if the ruthenium-containing polymer does not have an epoxy group as an action group capable of forming a cross-linking bond, a desired side wall can be formed. And the baking temperature required for the formation of the side wall can be set to a condition that φ is relatively low temperature of not more than 150 °C. [Embodiment] The polydecane is a polymer or oligomer in which the main chain is formed by Si-Si bonding, and a specific example of the structural unit is as follows. However, the structural unit of polydecane is not limited to these examples. [Chemical 3]

201026754

In order to increase the ruthenium content of the polydecane, R2 of the above formula (2) or the above formula (3) is preferably a methyl group or an ethyl group which is independently independent, and R1 of the above formula (2) is preferably an argon atom, a methyl group or Ethyl. The main chain of the above polydecane may be either a linear type or a branched type. The solvent containing the organic solvent as a main component contained in the composition for forming a side wall of the present invention contains the organic solvent in an amount of more than 50% by mass, for example, 60% by mass to 1% by mass. Such organic solvents, for example, 4-methyl-2-pentanol, 1-butanol, propylene glycol n-propyl ether, propylene glycol n-butyl ether, propylene glycol phenyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, two Propylene glycol dimethyl ether, tripropylene glycol methyl ether, propylene glycol diacetate, cyclohexanol acetate, and cyclohexanol. The optimum organic solvent can be selected from the above-mentioned organic solvent by the type of organic photoresist used for forming the photoresist pattern. For example, when using the organic photosensitive material manufactured by Sumitomo Chemical Co., Ltd. under the trade name of P AR8 5 5, the above organic solvent is preferably, for example, 4-methyl-2-pentanol, propylene glycol n-butyl ether or propylene glycol phenyl ether. , dipropylene glycol, acrylic acid, dipropylene glycol n-butyl ether, tripropylene glycol formic acid, and cyclohexanol. Further, the solvent component is, for example, dipropylene glycol formic acid, tripropylene glycol n-butyl ether, dipropylene glycol methyl ether acetate, 1,3-butanediol diacetate vinegar, -10-201026754 methyl acetate, ethyl acetate, acetic acid Isopropyl ester, n-propanol 'n-propyl acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol Alcohol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 1,3-butylene glycol, triacetin, B Glycol monomethyl ether acetate, ethylene glycol monoacetic acid, ethylene glycol monoethyl ether acetate, ethyl lactate, and cyclohexanone. φ The solvent described above must have almost no intermixing with the photoresist pattern, and the coating property with respect to the substrate on which the photoresist pattern is formed is good. An organic solvent having a boiling point of 100 ° C or less at 1 atm (101.3 kPa) is easily volatilized during coating, and the surface tension of water is high and it is difficult to apply uniformly. Therefore, when such a solvent is used as a main component At the time, the coating property with respect to the substrate was not good. However, an organic solvent having a boiling point of 100 ° C or less or less may be contained as an auxiliary component of the solvent. The ruthenium-containing polymeric ruthenium contained in the composition for forming a side wall of the present invention has a sterol group at its terminal. By analyzing the composition using an FT-NIR (Fourier Transform Near Infrared) spectrometer, the presence of a sterol group can be inferred. The composition for forming a side wall of the present invention may further contain a surfactant. The surfactant can enhance the coating property of the coating film composition with respect to the substrate. For example, a nonionic surfactant or a fluorine-based surfactant can be used. Further, the composition for forming a side wall of the present invention may further contain an organic acid. The organic acid is advantageous for enhancing the storage stability of the composition for forming a side wall of the present invention. -11 - 201026754 Such organic acids, for example, maleic acid, cis-5-norbornene-endo-2,3-dicarboxylic acid, cis-5-norbornene-exo-2,3-di a cis-dicarboxylic acid such as a carboxylic acid or cis-1,2-cyclohexanedicarboxylic acid. When the component obtained by removing the solvent from the side wall forming composition of the present invention is regarded as a solid portion, the ratio of the solid content to the composition is, for example, 1% by mass to 30% by mass. Further, the ratio of the organic acid to the solid content is, for example, 0.1% by mass to 10% by mass. Further, the ratio of the surfactant to the solid content can be, for example, 1% by mass to 2% by mass. The composition for forming a side wall of the present invention is applied by coating a photoresist pattern formed on a semiconductor substrate, and the photoresist pattern is formed using an organic photoresist. The organic photoresist may be either a positive photoresist or a negative photoresist, and is a photoacid generator. Chemically amplified photoresists capable of sensitizing KrF excimer lasers, ArF excimer lasers, and EUV (Ultra Ultraviolet) can be used. In the present specification, "organic photoresist" is defined as a photoresist containing no ruthenium based on a polymer such as polysiloxane or polydecane. The photoresist pattern is preferably formed on the semiconductor substrate by a light-shielding film of one or more layers. The semiconductor substrate, typically a germanium wafer, may also use an SOI (Silicon On Insulator) substrate, or gallium arsenide (GaAs), indium phosphide (InP), or gallium phosphide (GaP). ) Compound semiconductor wafers. An insulating film formed of a hafnium oxide film, a niobium oxide film (SiON film) containing nitrogen, a hafnium oxide film containing carbon (SiOC film), a hafnium oxide film containing fluorine (SiOF film), or a low-k may be used. A semiconductor substrate of a film (low specific dielectric constant film). -12- 201026754 EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to those described in the following examples. The average molecular weight of the polymer shown in the following synthesis examples of the present specification is a result of measurement by gel permeation chromatography (hereinafter abbreviated as GPC; Gel Permeation Chromatography). The devices, conditions, etc. used by φ are as follows. GPC device: HLC-8220GPC (manufactured by Tosoh Co., Ltd.) GPC Pipe column: Shodex (registered trademark) KF8 03 L, KF802, KF801 (manufactured by Showa Denko Co., Ltd.) Column temperature: 40 ° C Solvent: Tetrahydrofuran (ΤΗF) Flow rate: 1.0 ml/min Standard sample: Polystyrene (manufactured by Showa Denko KK) &lt;Synthesis Example 1 &gt; 20.31 g of tetraethoxy decane, 1.49 g of phenyltrimethoxydecane, and methyltriethoxydecane 8.02 33.34 g of g and ethanol were placed in a 100 ml flask and dissolved, and then 3 g of guanidine hydrochloride was dissolved in an aqueous solution of 9.83 g of ion-exchanged water, and the mixture was dropped into the flask at room temperature and stirred. Then, reflux was carried out for 2 hours, and the resulting reaction solution was cooled to room temperature. Then, 100 g of 4-methyl-2-pentanol was added to the reaction solution, and methanol and ethanol as reaction by-products, and water and hydrochloric acid were distilled off under reduced pressure to obtain a hydrolysis condensate solution -13 - 201026754. The average molecular weight of the obtained polymer or oligomer based on GPC is, in terms of standard polystyrene, a weight average molecular weight of 55 00. &lt;Synthesis Example 2 &gt; 76.76 g of tetraethoxynonane, 8.12 g of phenyltrimethoxydecane, and 84.8 8 g of 4-methyl-2-pentanol were placed in a 300 ml flask and dissolved, and then 1.49 g of butenedioic acid was dissolved in an aqueous solution of 28.75 g of ion-exchanged water, and the mixture was dropped into the flask at room temperature and stirred. Then, the reaction was carried out for 1 hour at 1 ° C, and the resulting reaction solution was cooled to room temperature. Next, 200 g of propylene glycol monomethyl ether acetate was added to the reaction solution, and methanol, ethanol, and water as reaction by-products were distilled off under reduced pressure to obtain a hydrolysis condensate solution. The average molecular weight of the obtained polymer or oligomer measured by GPC is, in terms of standard polystyrene, a weight average molecular weight of 4,500. &lt;Synthesis Example 3 &gt; 5.66 g of tetraethoxydecane 3, 17.85 g of methyltriethoxydecane, and 0.27 g of ethanol 8 were placed in a 300 ml flask and dissolved, and then 0.01 mol/L hydrochloric acid was added. 16.99 g of an aqueous solution was dropped into the above flask at room temperature and stirred. Then, reflux was carried out for 4 hours, and the resulting reaction solution was cooled to room temperature. Then, 100 g of 4-methyl-2-pentanol was added to the reaction solution, and ethanol of the reaction by-product, and water and hydrochloric acid from the aqueous hydrochloric acid solution were distilled off under reduced pressure to obtain a hydrolysis condensate solution. The average molecular weight of the obtained polymer or oligomer based on GPC was calculated by standard polystyrene to have a weight average molecular weight of 1400. 201026754 &lt;Synthesis Example 4 &gt; 30-31 g of tetraethoxydecane, 35.42 g of methyltriethoxydecane, and 98.59 g of ethanol were placed in a 300 ml flask and dissolved, and then 〇.〇1 mol/L hydrochloric acid was added. 21.44 g of an aqueous solution was dropped into the above flask at room temperature and stirred. Then, reflux was carried out for 4 hours, and the resulting reaction solution was cooled to room temperature. Next, 4-methyl-2-pentanol l〇〇g is added to the reaction solution, and the ethanol of the anti-φ by-product, and the water and hydrochloric acid from the aqueous hydrochloric acid solution are distilled off under reduced pressure to obtain a hydrolysis condensate. Solution. The average molecular weight of the obtained polymer or oligomer based on GPC was calculated by standard polystyrene to have a weight average molecular weight of 1,800. &lt;Synthesis Example 5 &gt; 14.26 g of tetraethoxydecane, 8.8 8 g of methyltriethoxydecane, and 79.73 g of ethanol were placed in a 300 ml flask and dissolved, and then 0.01 mol of φ / L aqueous hydrochloric acid solution was added. 17.78 g was dropped into the above flask at room temperature and stirred. Then, reflux was carried out for 4 hours, and the resulting reaction solution was cooled to room temperature. Then, 100 g of 4-methyl-2-pentanol was added to the reaction solution, and ethanol of the reaction by-product, and water and hydrochloric acid from the aqueous hydrochloric acid solution were distilled off under reduced pressure to obtain a hydrolysis condensate solution. The average molecular weight of the obtained polymer or oligomer based on GPC was calculated by standard polystyrene to have a weight average molecular weight of 2,100. &lt;Example 1&gt; -15-201026754 4-methyl-2-pentanol was added to 25 g of the solution obtained in Synthesis Example 1 to prepare a 4.0% by mass solution. Then, it was filtered using a polyethylene microfilter having a pore diameter of 0.02 m to prepare a composition for forming a side wall (solution). <Example 2 &gt; 0.10 g of maleic acid and a surfactant (manufactured by DIC Corporation) Product name: Megafac R-30) 0.02 g of 25 g of the solution obtained in Synthesis Example 1 was added, followed by the addition of 4-methyl-2-pentanol to form a 4.0% by mass solution. Then, it was filtered using a polyethylene microfilter having a pore size of 〇.〇2/zm to prepare a composition (solution) for forming a side wall. &lt;Example 3 &gt; [Chemical 4]

The polypot compound represented by the above formula (16) is prepared (wherein, r each independently represents a hydrogen atom, a methyl group, an ethyl group, an OH group or a phenyl group, and the X system independently represents an OH group or a hydrazine H group and hydrogen. Atomic) (manufactured by Osaka Gas Chemicals Co., Ltd., weight average molecular weight 5900, number average molecular weight 1 800, respectively, containing structural units A and structural units B' at a ratio of 3 3 mol%/6 4 mol% The terminal has at least a sterol group). Next, 4_methyl-2-pentanol was added to a solution of hexanol in a concentration of 2% by mass of the 4-methyl-2-pentanol compound containing the polydecane compound to form a 4.0% by mass solution. Then, it was filtered using a polyethylene microfilter having a pore size of 〇·〇2 to prepare a composition (solution) for forming a side wall of -16 to 201026754. In the present embodiment, the polydecane compound to be used is not inhibited from containing the branched structure represented by the above formula (3) described in the present specification. In the polydecane compounds used in Examples 4 to 8 described below, 'the same as in the present example, the branched structure was not hindered. &lt;Example 4 &gt; ❿ [Chemical 5]

(17) The polydecane compound represented by the above formula (17) is prepared (wherein R represents a hydrogen atom, a methyl group, an ethyl group, an OH group or a phenyl group, and the X system independently represents an OH group or an OH group and a hydrogen atom, respectively. (Osaka Gas Chemicals Co., Ltd., having a weight average molecular weight of 5,900, a number average molecular weight of 1,500, and at least a sterol group at the φ end). Then, 4-methyl-2-pentanol was added to a solution of a 4-methyl-2-pentanol solution of the polydecane compound at a concentration of 20% by mass to form a solution of 4.0% by mass. Then, it was filtered using a polyethylene microfilter having a pore diameter of 0.02 // m to prepare a composition (solution) for forming a side wall. &lt;Example 5 &gt; 201026754 [Chem. 6]

The polydecane compound represented by the above formula (16) is prepared (wherein R each independently represents a hydrogen atom, a methyl group, an ethyl group, an OH group or a phenyl group, and the X system independently represents an OH group or an OH group and a hydrogen atom) (Osaka Gas Chemicals Co., Ltd., having a weight average molecular weight of 7,200 and a number average molecular weight of 1,800, respectively containing structural units A and structural units B in a ratio of 20 mol% and 80 mol% different from Example 3, at least at the end Has a sterol group). Then, 4-methyl-2-pentanol was added to 165.0 g of a 4-methyl-2-pentanol solution containing the polydecane compound at a concentration of 20% by mass to form a solution of 4.% by mass. Then, it was filtered using a polyethylene microfilter having a pore size of 〇.〇2 //m to prepare a composition (solution) for forming a side wall. &lt;Example 6 &gt; [Chem. 7]

Η3 士 C丨s, IR

Ηδ 2 c—0S—R 6

+/C 8)

The polydecane compound represented by the above formula (18) is prepared (wherein R represents independently a hydrogen atom, a methyl group, an ethyl group, a hydrazine H group or a phenyl group), and the X system independently represents a hydrazine H group or an OH group and hydrogen. Atom) (Osaka Gas

Chemicals Co., Ltd., weight average molecular weight 14000 'quantitative average -18- 201026754 molecular weight 2000 ' contains structural unit A, structural unit 8 and structural unit c in a ratio of 35 mol%, 60 mol%, and 5 mol%, respectively. It has at least a sterol group at the end. Then, 4-methyl-2-pentanol was added to 165.0 g of a 4-methyl-2-pentanol solution containing the polydecane compound at a concentration of 20% by mass to prepare a 4.0% by mass solution. Then, it was filtered using a polyethylene microfilter having a pore size 〇 2 in m to prepare a side wall forming composition (solution). <Example 7 &gt; [Chemical 8]

The polydecane compound represented by the above formula (18) is prepared (wherein R each independently represents a hydrogen atom, a methyl group, an ethyl group, an OH group or a phenyl group, and the X system

Made by Chemicals AG, having a weight average molecular weight of 5,500 and a number average molecular weight of 1,500, respectively, at 15 moles different from Example 6. /. The ratio of 80 mol% to 5 mol% contains the structural unit A, the structural unit B, and the structural unit C, and has at least a sterol group at the terminal. Further, 4_methyl-2-pentanol was added to 165.0 g of a 4-methyl-2-pentanol solution containing the polydecane compound at a concentration of 20% by mass to form a 4.0% by mass solution. Then, it was filtered using a polyethylene microfilter having a pore size of 〇·〇2 # m to prepare a composition for forming a side wall (solution). -19 - 201026754 &lt;Example 8 &gt; [Chem. 9]

The polydecane compound represented by the above formula (18) is prepared (wherein RQ each independently represents a hydrogen atom, a methyl group, an ethyl group, an OH group or a phenyl group, and the X system independently represents an OH group or a hydrazine H group and a hydrogen atom, respectively. (manufactured by Osaka Gas Chemicals Co., Ltd., having a weight average molecular weight of 5,500 and a number average molecular weight of 1,500, respectively, in a ratio of 15 mol%, 75 mol%, and 10 mol% different from Examples 6 and 7, respectively. Unit A, structural unit B, and structural unit C have at least a sterol group at the end. Then, 4-methyl-2-pentanol was added to 165.0 g of a 4-methyl-2-pentanol solution containing the polydecane compound at a concentration of 20% by mass to form a 4.0% by mass solution. Then, 9 was filtered with a polyethylene microfilter having a pore diameter of 0.02 to prepare a side wall forming composition (solution). [Dry Etching Speed] For the tantalum wafer, the film corresponding to the sidewall formed by the side wall forming composition (solution) prepared in Example 1 and Example 3 was used, and the organic photoresist was used (Sumitomo Chemical Co., Ltd.) The photoresist film formed by the company, product name, and PAR8 55) was dry-etched using 〇?4 or 〇2 as an etching gas-20-201026754, and the dry etching rate was measured. The apparatus used for the dry etching was RIE-10NR (manufactured by Samco Co., Ltd.). This film corresponding to the side wall was formed by spin-coating the above-described composition for forming a side wall (solution) and baking at 150 ° C for 60 seconds. The first table shows the results of obtaining the ratio of the dry etching rate of the film corresponding to the side wall to the dry etching rate of the resist film (corresponding to the film of the side wall/resist film). 〇 [Table 1] Table 1 dry etching rate ratio cf4 〇 2 Example 1 1.47 0.10 Example 3 1.45 0.03 [Example of use of the side wall forming composition of the present invention] o The above formula has a content, The circular crystal structure of the aggregate is located in the single 10] - Λ 匕 [&lt; 9 Table 2 IIJp. H3\ cue - cuoncuo H2 C-H20=

HC-HC

Η H

Ho c—c—c—oIcIc—c H3 H2

H , 3 3 H . i c—c·-c—o—:HI Jl p Ho H2C, 21

VU/ 9

Q 201026754 Crosslinking agent (made by Japan Cytec Industries Co., Ltd., trade name: POWDERLINK (registered trademark) 1174) and p-toluenesulfonic acid pyridinium salt, forming a photoresist base film 102, and using organic photoresist (Sumitomo Chemical Co., Ltd.) Company name, product name: PAR855), as shown in Fig. 1 (A), a photoresist pattern 103 is formed thereon. Target process line width (

Critical Dimension) is 80nm, L/S = 80/240, and an ArF excimer laser is used as the light source during exposure. The photoresist pattern 103 contains a photoacid &amp; (4) ° and then the sidewall forming composition prepared in Example 1 is spin-coated in a manner of coating the photoresist pattern 103 (1 500 rpin, 60). Second), as shown in Fig. 1(B), the coating layer 104 is formed. No baking was done at this time. Then, as shown in Fig. 1(C), UV irradiation is performed on the entire surface of the coating layer 104 to expose. For the light source used in this exposure, an ArF quasi-molecular laser can be used. The irradiation energy of UV or the like is in the range of 10 mJ/cm 2 to 100 mJ/cm 2 , and the irradiation time is, for example, 2 seconds to 60 seconds. Then, sidewalls 1 〇 5 were formed around the photoresist pattern by baking at 150 ° C for 60 seconds. The baking temperature is from 80 ° C to 200 ° C, preferably from 80 ° C to 150 ° C, and must be set so that the photoresist pattern is softened and does not flow. The heating means used in baking is not particularly limited, and for example, a hot plate can be used. Next, 4-methyl-2-pentanol is used to remove the coating layer 104 where the sidewalls 105 are not formed. If only the coating layer 1〇4 can be selectively removed, 4-methyl-2-pentanol can also be used, but propylene glycol monomethyl ether (PGME) or propylene glycol monomethyl ether acetate (PGMEA) cannot be used. The solvent of PGMEA and PGME and the tetramethylammonium hydroxide (TMAH) water-soluble -22-201026754 solution were mixed at a ratio of 3:7. The state after removal is as shown in Fig. 2(A). The residual 4-methyl-2-pentanol was then removed by spin drying (3 Torr rpm, 30 sec). Further, the sidewalls 1〇5 are dry-etched using CF4 as an etching gas, whereby the upper portion of the photoresist pattern 103 is exposed as shown in Fig. 2(B). For the dry etching apparatus, RIE-10NR (manufactured by Samco Co., Ltd.) was used. In the dry etching, the exposed portion of the photoresist underlayer film, that is, the portion where the photoresist pattern 103 and the sidewall 105 are not formed, may be etched. φ Finally, dry etching for removing the photoresist pattern 103 is performed using 〇2 as an etching gas, and the sidewall 105 is left as shown in Fig. 2(C). For the dry etching apparatus, RIE-1 ONR (manufactured by Samco Co., Ltd.) was used. In the dry etching, a portion of the surface of the photoresist underlayer film 102 where the sidewalls 105 are not formed may also be etched. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a step of forming a side wall. β Fig. 2 is a schematic view showing a step of forming a side wall. [Main component symbol description] 1 〇 1 : 矽 wafer 102 : photoresist underlayer film 103 : photoresist pattern 104 : coating layer 105 : sidewall state _______________ -23-

Claims (1)

201026754 VII. Patent application: 1 · A composition for forming a sidewall for lithography, which comprises: a polymer containing sand and a solvent containing an organic solvent as a main component; It has a sterol group at its end and has a structural unit represented by the following formula (1 a ) and formula (1 b ); [Chemical Formula 1] R3 — (1a) (1b) (wherein R 3 represents a methyl group, Ethyl or phenyl); The above organic solvent is selected from the group consisting of 4-methyl-2-pentanol, propylene glycol n-butyl ether, propylene glycol phenyl ether 'dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, ring At least one selected from the group consisting of alcohol, 1-butanol, propylene glycol n-propyl ether, dipropylene glycol dimethyl ether, propylene glycol diacetate, and cyclohexanol acetate. (2) A composition for forming a side wall for lithography, comprising: a polymer containing ruthenium and a solvent containing an organic solvent as a main component; and the ruthenium-containing polymer having a sterol group at a terminal thereof Or the sterol group and the hydrogen atom, and having at least one of the structural units represented by the following formula (2) and/or the following formula (3); [Chemical 2] (wherein R 2 represents independently methyl, ethyl or phenyl, R 1 represents a hydrogen atom, methyl, ethyl, OH or phenyl); -24- 201026754 Base-2-pentanol, propylene glycol n-butyl ether, propylene glycol phenyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, cyclohexanol, 1-butanol, propylene glycol n-propyl ether, dipropylene glycol At least one of the group consisting of methyl ether, propylene glycol diacetate, and cyclohexanol acetate. 3. A composition for forming a side wall for lithography according to claim 1 or 2, which further comprises an organic acid. The composition for forming a side wall for lithography according to any one of claims 1 to 3, which further comprises a surfactant. -25-