JP2006178004A - Radiation sensitive composition and method for manufacturing electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation sensitive composition giving a high-resolution positive pattern having reduced edge roughness, and to provide a method for manufacturing an electronic device using the same. <P>SOLUTION: The radiation sensitive composition contains as a principal component a compound or resin having a structure in which at least two or more polynuclear phenolic compounds having five or more benzene rings and five or more hydroxyl groups, wherein the number of hydroxyl groups bonding to one benzene ring is two or less, link through an acid decomposable group, wherein the purity of the polynuclear phenolic compounds is ≥90% with respect to a ratio of a peak area corresponding to the principal component measured by gel permeation chromatography. By using the positive radiation sensitive composition as a resist, a high-resolution positive pattern having reduced edge roughness is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a manufacturing technique of an electronic device such as a semiconductor integrated circuit, an optical disk, and a hard disk, and particularly relates to a radiation-sensitive composition used in a lithography process for accurately forming a fine pattern.

In recent years, with the high integration and miniaturization of semiconductor integrated circuits, the exposure light source is also changed from i-line (365 nm) to KrF excimer laser (248 nm), ArF excimer laser (193 nm), and F ₂ excimer laser (157 nm). Shortening of the wavelength has been promoted, and lithography using extreme ultraviolet (EUV), electron beam, and X-ray is also being studied. At present, resist patterns having a minimum processing dimension of 0.2 μm to 0.1 μm are actively formed, and some advanced researches target pattern formation of 0.1 μm or less.

  As a resist used for the fine processing as described above, in addition to high resolution, sensitivity and a good pattern shape are required. As resists that satisfy these requirements, chemical amplification resists that cause a reaction that changes the solubility in a developing solution by the catalytic action of acid generated by exposure have attracted attention, and many chemical amplification resist compositions have been proposed. Yes.

  The positive chemically amplified resist composition includes a three-component system including a matrix resin, a compound that changes to a development medium affinity substance by an acid-catalyzed reaction induced by exposure, and an acid generator that generates acid by exposure. There are two-component systems including a resin in which the matrix resin itself changes to affinity for the development medium and an acid generator that generates an acid upon exposure.

  Examples of the compound that changes to the development medium affinity substance include phenolic compound derivatives in which some or all of the hydroxyl groups are protected with acid-decomposable groups such as acetal, ketal, and t-butoxycarbonyl group. Examples of the resin whose matrix resin itself changes to development medium affinity include, for example, a resin in which the hydroxyl group of polyhydroxystyrene is protected with an acid-decomposable group, and the alkali-soluble group (hydroxyl group, copolymer of vinylphenol and acrylic monomer). There are resins in which a carboxyl group) is protected with an acid-decomposable group, and resins in which alkali-soluble groups of alicyclic compounds and acrylic monomers are protected with an acid-decomposable group.

  However, the above-described conventional resist has a problem that edge roughness becomes apparent as the size is reduced. The edge roughness (or line edge roughness) is that the edge of the interface between the resist line pattern and the substrate exhibits a shape that varies irregularly in a direction perpendicular to the line direction. When this pattern is observed from directly above, the edges appear uneven, and the size of the unevenness reaches several nanometers to several tens of nanometers. Since the unevenness is transferred from the resist pattern to the circuit pattern by etching, the electrical characteristics of the circuit pattern are deteriorated and the yield is reduced. At present, the size of the unevenness is required to be 10% or less of the line pattern width. For example, when forming a 90 nm wide line pattern, it is required to reduce the line edge roughness to 9 nm or less.

  Since the conventional positive radiation sensitive composition uses a polymer resin (weight average molecular weight of 5000 or more) for the resist matrix, if the size of one molecule of the resin is regarded as the mean square of the distance between both ends of the Gaussian chain, It can be estimated to be several nanometers to several tens of nanometers. Furthermore, the polymer resin is composed of polymers having various molecular weights. Since polymers having different molecular weights have different solubility in a developing solution, it is very difficult to reduce edge roughness as long as they are used as a matrix.

  Therefore, it has been proposed to use a low molecular material for the resist matrix. As described in Patent Document 1 (Japanese Patent Laid-Open No. 2000-305270) as a positive-type radiation-sensitive composition, a low molecular weight compound in which the hydroxyl group of polynuclear phenol is protected with an acid-decomposable group is used as a resist matrix. Proposed. Thus, since the low molecular weight material can reduce the molecular size and molecular weight distribution compared to the polymer resin, it can be expected to improve the edge roughness to some extent.

  However, in the low molecular weight material of the above-mentioned patent document, when a compound in which the alkali-soluble group of the molecular material is protected with an acid-decomposable group is used as a positive resist matrix, the resist film is easily crystallized and the composition is uniform. Thus, there is a problem in that a film distributed in the region cannot be obtained, sufficient resist characteristics (resolution, sensitivity, edge roughness) cannot be obtained, and in addition, the resist pattern is a low-molecular compound, so that the heat resistance is poor.

Therefore, as a composition that meets the demand for reducing the roughness of a positive resist, Patent Document 2 (Japanese Patent Laid-Open No. 2000-292927) proposes a high-performance matrix resin of a molecular weight change type. As this resin, a resin in which a polynuclear phenol compound excellent in alkali solubility and a resin having a low polydispersity are bonded via an acid-decomposable group is used. As for the molecular weight change type resin, an original low molecular weight resin and a resin having a low polydispersity are regenerated by an acid-catalyzed reaction. Accordingly, the solubility of the exposed portion can be improved, the molecular weight appearing in the exposed portion can be reduced and the molecular weight can be reduced, and a positive pattern with high resolution and small edge roughness can be formed.
JP 2000-305270 A JP 2000-292927 A

  However, even if a molecular weight change type resin as described in Patent Document 2 is used, it is difficult to satisfy the demand for fine edge line edge roughness of 0.1 μm or less, and further improvement is required.

  The polynuclear phenol compound contains a certain proportion of side reaction products (impurities) during synthesis. For example, in the synthesis of a hydroxybenzyl group adduct to monodispersed trisphenols described in Patent Document 2, the resulting polynuclear phenol compound contains 3 to 36% impurities.

  According to recent studies by the present inventors, it has been clarified that the impurities are an obstacle to the reduction of edge roughness because the chemical structure and alkali solubility are different from the low molecular weight material as the main component.

  An object of the present invention is to provide a radiation-sensitive composition capable of obtaining a high-resolution positive pattern with reduced edge roughness.

  Another object of the present invention is to provide a method for producing an electronic device using the radiation sensitive composition.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  As a result of intensive studies, the present inventors have found that the sensitivity and edge roughness of a resist using a molecular weight changing resin greatly change depending on the purity of the polynuclear phenol compound, and have reached the present invention.

  That is, the above first object of the present invention is to provide a hydroxyl group having 5 or more benzene rings, 5 or more hydroxyl groups, and one benzene ring in a radiation-sensitive composition whose molecular weight is reduced by irradiation. Is a radiation-sensitive composition comprising as a main component a compound or resin having a structure in which at least two polynuclear phenol compounds having 2 or less are bonded via an acid-decomposable group, and the purity of the polynuclear phenol compound is a gel This is achieved by a composition characterized in that the ratio of the peak area corresponding to the main component measured by permeation chromatography is 90% or more and a pattern forming method using this composition.

  As the polynuclear phenol compound of the present invention, those having 5 or more benzene rings, 5 or more hydroxyl groups, and 2 or less hydroxyl groups in one benzene ring are preferable. When the number of benzene rings and hydroxyl groups is smaller than this, the molecular weight of the compound bonded via the acid-decomposable group is small, so that the solubility in an alkaline aqueous solution is high, and a resolution of 0.1 μm or less is obtained. Becomes difficult.

  Examples of the polynuclear phenol compound used in the present invention include 2,2-bis (4-hydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, tris (4-hydroxyphenyl) ethane, α, α, α′-tris. (4-hydroxyphenyl) -1-ethyl-4-isopropylbenzene, 2,6-bis [(2-hydroxy-5-methylphenyl) methyl] -4-methylphenol, 2,2′-methylenebis [6- [ (2-hydroxy-5-methylphenyl) methyl] -4-methylphenol], 2,4,6-tris (4-hydroxyphenylmethyl) 1,3-benzenediol, 4- [bis (4-hydroxyphenyl) Methyl] -2-methoxyphenol, α, α, α′-tris (4-hydroxy-3-methylphenyl] -1-ethyl-4- Sopropylbenzene, 4,4 ′-[(4-hydroxyphenyl) methylene] bis [2-cyclohexyl-5-methylphenol], 4,4 ′, 4 ″, 4 ′ ″-(1,2-ethanediylidene ) Tetrakisphenol, 4,4 ′, 4 ″, 4 ′ ″-(1,2-ethanediylidene) tetrakis [2-methylphenol], 2,6-bis [(4-hydroxyphenyl) methyl] -4- A compound in which at least one selected from a hydroxybenzyl group, a hydroxyalkylbenzyl group, and a dihydroxybenzyl group is substituted with methylphenol, 2,2-bis (4-hydroxyphenyl) propane, etc. in the range of 3-6, Hydroxybenzyl, hydroxyalkylbenzyl, dihydroxybenzyl, hydroxyphenyl ether , A compound obtained by adding at least one selected from a hydroxyalkylphenyl ether group and a dihydroxyphenyl ether group in the range of 3 to 12, and 4,4′-methylenebis [2- [di (4-hydroxy-2,5-dimethyl Phenyl)] methyl] phenol and compounds obtained by substituting at least one selected from a hydroxybenzyl group, a hydroxyalkylbenzyl group and a dihydroxybenzyl group in the range of 3-6.

  In the synthesis of adducts of the above-mentioned hydroxybenzyl group, hydroxyalkylbenzyl group, and dihydroxybenzyl group, dimers and multimers of polynuclear phenol are produced as by-products in addition to the target compound. The synthesis is performed by reacting polynuclear phenol with formalin under a base catalyst to produce a methylolated polynuclear phenol, and then reacting the methylol with a phenol compound under an acid catalyst. In the reaction under the acid catalyst, methylols are condensed with each other to produce dinuclear and multimeric polynuclear phenols.

  These by-products differ from the target adduct in chemical structure and alkali solubility. Therefore, the purity of the polynuclear phenol is preferably 90% or more. When a molecular weight change type resin is formed from polynuclear phenol containing more by-products than this, the efficiency and alkali solubility of the acid-catalyzed decomposition reaction are non-uniform, and the resist sensitivity is lowered and the edge roughness is increased. Further, since the resist scum increases, the dimensional variation in etching increases, which is not preferable.

  As the compound capable of binding at least two polynuclear phenol compounds, a compound having at least two vinyl ether groups in one molecule is preferable. A molecular weight change type resin can be obtained by the above-mentioned vinyl ether compound, polynuclear phenol and acid catalyst addition reaction. For example, phenols having two or more phenolic hydroxyl groups such as resorcinol, catechol and hydroquinone, phenols having three or more phenolic hydroxyl groups such as pyrogallol and hydroxyhydroquinone, 2,2-bis (4-hydroxyphenyl) propane, etc. Compounds in which some or all of the hydrogen atoms of the hydroxyl groups of bisphenols, trisphenols, trinuclear phenols, and tetrakisphenols are substituted with at least one selected from ethyl vinyl ether groups, methyl vinyl ether groups, and vinyl ether groups Is preferred. Furthermore, aromatic carboxylic acids having a carboxy group, for example, compounds in which all of trimesic acid is substituted with at least one selected from an ethyl vinyl ether group, a methyl vinyl ether group, and a vinyl ether group are preferred.

  Further, some or all of the hydrogen atoms of the hydroxyl group of cycloalkanes, biphenyls, naphthalenes, and anthracenes having two or more hydroxyl groups or glycoloyl groups are ethyl vinyl ether groups, methyl vinyl ether groups, vinyl ether groups. A compound substituted with at least one selected from can also be used.

  The radiation-sensitive composition of the present invention is one that is dissolved in a solvent that dissolves each of the above components and applied onto a substrate. Examples of usable solvents include methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol. Examples include, but are not limited to, monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl methoxypropionate, methyl ethoxypropionate, ethyl lactate, diacetone alcohol, cyclohexanone, and 2-heptanone.

  The resist composition of the present invention includes, for example, a surfactant for preventing striation (coating unevenness) and improving developability, bisphenols for adjusting the resin dissolution rate, trisphenol alkanes, Low molecular phenolic compounds such as trinuclear phenols and tetrakisphenols, compounds or polymers containing protecting groups (acetal groups, ketal groups, t-butoxycarbonyl groups, etc.) that are deprotected (separated) by acid catalysts, resists A storage stabilizer for the solution, a basic compound for suppressing diffusion of the acid catalyst to the non-exposed portion, an ion dissociative compound such as onium halide, and a humectant such as tetraethylene glycol can be blended as necessary. .

  In addition, the polynuclear phenol has a small interaction between molecules and has no polymer chain entanglement like a conventional resist, so it can have solubility in nonpolar supercritical fluids such as carbon dioxide. .

  Carbon dioxide is known to be in a supercritical state at a pressure and temperature above the critical point (temperature critical point of carbon dioxide: 31 ° C., 73 atm) and to have a dissolving power comparable to hexane. However, this dissolving power increases the pressure and can be made stronger depending on the increase in fluid density. Therefore, a matrix resin insoluble in a supercritical fluid is formed by a structure in which at least two polynuclear phenol compounds are bonded via an acid-decomposable group. In the chemically amplified resist using this resin, the original polynuclear phenol is regenerated in the exposed area and becomes soluble in the supercritical fluid, so that a positive pattern can be obtained. The polynuclear phenol may have a low-polarity acid-decomposable group (for example, a tetrahydropyranyl group or a perfluoroalkyl acetal group) or an alkyl, if necessary, before forming a structure in which at least two or more are bonded via an acid-decomposable group A hydroxyl group can be protected with an ether group or a perfluoroalkyl ether group.

  A radiation-sensitive composition containing as a main component a compound or resin having a structure in which at least two polynuclear phenol compounds are bonded via an acid-decomposable group is developed, for example, as follows (see FIG. 1). The resist exposure is performed by a conventional lithography apparatus, the exposed wafer is set in a supercritical developing apparatus, and development-rinse-drying is performed. Carbon dioxide is released as a gas during drying. A specific development process is shown in FIG. It is a graph which shows the pressure in a container when using carbon dioxide as a supercritical fluid, and the relationship of time. When the temperature is 31 ° C., the liquid carbon dioxide reaches a critical pressure at 73 atm and becomes a supercritical fluid. Development is performed for a predetermined time at a pressure higher than this, preferably 100 to 300 atm. After that, rinsing is performed at 73 atm, and further depressurization changes the state of supercritical carbon dioxide into a gas, which is released to the outside of the container. This completes the drying of the resist pattern.

  The method for manufacturing an electronic device of the present invention includes a step of forming a resist pattern on a substrate by the above-described pattern forming method, and etching the substrate using the resist pattern as a mask. Examples of the etching process used in the method for manufacturing an electronic device according to the present invention include dry etching methods such as plasma etching and reactive ion etching. In addition, as a substrate processed in the method for manufacturing an electronic device of the present invention, a silicon dioxide film formed by a CVD method or a thermal oxidation method, an oxide film such as a coating type glass film, or a nitride film such as a silicon nitride film is used. Can be mentioned. Moreover, aluminum, its alloy, various metal films, such as tungsten, polycrystalline silicon, etc. are mentioned.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  Resist patterns with high resolution and small edge roughness can be formed for exposure to active actinic radiation, particularly light, ultraviolet, far ultraviolet, vacuum ultraviolet, extreme ultraviolet, X-ray, ion beam, or electron beam. Further, a positive resist pattern can be formed by developing the resist film subjected to pattern exposure in a supercritical fluid. In addition, since there is no need to worry about wastewater treatment of water and developer and environmental pollution, it is preferably used in a fine process for manufacturing semiconductor devices such as IC and LSI.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these. First, synthesis examples of materials used in the present invention will be shown.

(Resin synthesis example 1)
As a polynuclear phenol raw material, α, α, α′-tris (4-hydroxy-3-methylphenyl) -1-ethyl-4-isopropylbenzene to 4-hydroxybenzyl group hexaadduct (manufactured by Honshu Chemical Industry Co., Ltd.) (Trade name TPPA-1000P (molecular weight = 1060)) for the polynuclear phenol compound. The purity of the polynuclear phenol was measured using a gel permeation chromatography (GPC) system L-6000 (manufactured by Hitachi) using a differential refractometer L-3310 (manufactured by Hitachi) as a detector. The GPC column has a configuration in which gel packs A-140, A-120, and A-110 (manufactured by Hitachi Chemical) are connected in this order. Tetrahydrofuran (Wako Pure Chemical Industries, Ltd.) was used as the developing solvent. As a result, the ratio of the peak area corresponding to the main component was 73%. 150 g of this polynuclear phenol was dissolved in 450 g of anisole, 675 g of xylene was added and stirred for 2 hours, and then allowed to stand for 24 hours. The supernatant was concentrated under reduced pressure to precipitate a solid in hexane, filtered and vacuum dried to obtain 10 g of product. The purity of the resulting polynuclear phenol (α, α, α′-tris (4-hydroxy-3-methylphenyl) -1-ethyl-4-isopropylbenzene to 4-hydroxybenzyl group hexaadduct) is 98%. there were. FIG. 3 shows the molecular weight distribution.

  This high-purity polynuclear phenol compound: 8 g, as a vinyl ether compound, 1,3,5-tris (2-vinyloxy) ethoxy) benzene (a compound in which all three hydrogen atoms of phloroglucin are substituted with ethyl vinyl ether): 1. 6 g was dissolved in 70 ml of ethyl acetate. To this, 0.3 g of 2-ethylhexyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added and reacted at 50 ° C. for 5 hours. Thereafter, the reaction solution was transferred to a separatory funnel, washed by adding 100 ml of 3N potassium hydroxide, and washed with water until neutrality. The ethyl acetate solution washed with water was concentrated under reduced pressure to precipitate a solid in hexane, filtered and dried in vacuo to give the product. This product was a resin having a polystyrene-reduced weight average molecular weight (Mw): 5940 and polydispersity: 3.3 by GPC.

Example 1
The resin of Resin Synthesis Example 1 was dissolved in 2-heptanone to prepare a solution having a solid content concentration of 7% by weight. The above resist solution was dropped on a silicon wafer, heat-treated at 110 ° C. for 2 minutes after spin coating, and a resist film having a thickness of 0.15 μm was obtained. This resist film was immersed in an aqueous solution containing 2.38% by weight of tetramethylammonium hydroxide (TMAH) in a developing solution, and the dissolution rate (nm / second) was determined from the time required for the coating to dissolve. As a result, the dissolution rate of the coating film was 1. Onm / sec. Next, 100 parts by weight of resin in a resin synthesis example, and 4 parts by weight of triphenylsulfonium trifluorobutanesulfonate as a compound that generates an acid upon exposure, a resist prepared by dissolving in 2-heptanone to a solid content concentration of 7% by weight The solution was dropped onto a silicon wafer and spin-coated, and then heat treated at 110 ° C. for 2 minutes to obtain a resist film having a thickness of 0.15 μm. Next, using an electron beam lithography apparatus (acceleration voltage of the electron beam is 30 kV), this substrate is irradiated with an electron beam in a stepwise manner, and then subjected to heat treatment at 90 ° C. for 2 minutes to form a latent image portion of the resist film. Promoted the reaction to increase the solubility in. After the heat treatment described above, development was carried out by immersing in an aqueous solution containing 1.2% by weight of TMAH for 60 seconds. As a result, the sensitivity curve was as high as 3.5 μC / cm ² and the film was not reduced, and high contrast was obtained. Further, the radiation-sensitive composition was applied to the substrate in the same manner as described above, and after irradiation with a patterned electron beam with an electron beam drawing apparatus (electron beam acceleration voltage was 75 kV), the resist was subjected to heat treatment at 90 ° C. for 2 minutes. The reaction to increase the solubility of the latent image portion of the film in an aqueous alkaline solution was promoted. After the above heat treatment, development was performed by immersing in an aqueous solution containing 1.2% by weight of TMAH for 60 seconds. As a result, a fine pattern of 80 nm lines / intervals was formed at an electron beam irradiation dose of 17 μC / cm ² . As a result of measuring the line width of this pattern at 32 points using a scanning electron microscope, it was found that the variation in line width (3σ) was as high as 5.3 nm.

(Comparative Example 1)
Instead of the high-purity polynuclear phenol used in Resin Synthesis Example 1, 4-hydroxybenzyl group hexa to α, α, α′-tris (4-hydroxy-3-methylphenyl) -1-ethyl-4-isopropylbenzene The adduct (trade name TPPA-1000P (molecular weight = 1060) for the polynuclear phenol compound manufactured by Honshu Chemical Industry Co., Ltd.) was used as it was, and the resin synthesized in the same manner as in Resin Synthesis Example 1 was used (polystyrene conversion by GPC). Weight average molecular weight (Mw): 10100, polydispersity: 4.5). As a result of measuring the dissolution rate of the coating film of this resin in the same manner as in Example 1, the dissolution rate of the coating film was 1.0 nm / sec. Further, a resist solution was prepared in the same manner as in Example 1, and the sensitivity at 30 kV was measured. As a result, the sensitivity was 7 μC / cm ² . Furthermore, as a result of forming an 80 nm line / spacing pattern using an electron beam drawing apparatus (electron beam acceleration voltage is 75 kV), the line width variation (3σ) is 8.2 nm with a sensitivity of 25 μC / cm ^2. there were.

(Example 2)
In place of the 4-hydroxybenzyl group hexa adduct of α, α, α′-tris (4-hydroxy-3-methylphenyl) -1-ethyl-4-isopropylbenzene used in Resin Synthesis Example 1, 4′-methylenebis [2- [di (4-hydroxy-2,5-dimethylphenyl)] methyl] phenol (purity 98%) was used, and a resin synthesized in the same manner as in Resin Synthesis Example 1 was used (GPC). By weight average molecular weight in terms of polystyrene (Mw): 3970, polydispersity: 1.9). As a result of measuring the dissolution rate of the coating film of this resin in the same manner as in Example 1, the dissolution rate of the coating film was 1.0 nm / sec. Further, a resist solution was prepared in the same manner as in Example 1, and the sensitivity at 30 kV was measured. As a result, the sensitivity was ² μC / em ² . Furthermore, as a result of forming an 80 nm line / spacing pattern using an electron beam drawing apparatus (electron beam acceleration voltage is 75 kV), the line width variation (3σ) is 6.0 nm with a sensitivity of 16 μC / cm ^2. there were.

(Example 3)
4,4′-methylenebis [2- [di (4-hydroxy-2,5-dimethylphenyl)] methyl] phenol having a hydroxyl group substituted with a trifluoroethyl ether group (the substitution rate of the trifluoroethyl ether group is 50%) ) Was used for polynuclear phenol, and a resin synthesized in the same manner as in Resin Synthesis Example 1 was used (weight average molecular weight (Mw) in terms of polystyrene by GPC: 2100, polydispersity: 1.3).

  100 parts by weight of this resin and 10 parts by weight of diphenyliodonium triflate as an acid generator were dissolved in methyl cellosolve to prepare a resist solution having a solid concentration of 8% by weight. The above-mentioned resist was dropped on a silicon wafer, heat-treated at 110 ° C. for 2 minutes after spin coating, and a resist film having a thickness of 0.15 μm was obtained. Using an electron beam lithography system (acceleration voltage of the electron beam is 30 kV), this substrate is irradiated with an electron beam in a stepwise manner, and then heat treated at 90 ° C. for 2 minutes to dissolve the latent image portion of the resist film. Promoted reactions that increase sex.

  After the above heat treatment, the wafer was processed using the supercritical developing apparatus shown in FIG. In the developing device, a high-pressure carbon dioxide gas container 401 and a high-pressure pump 402 are connected by a pipe 403 to a high-pressure container 405 that can fix a wafer. In the middle of the pipe 403 is a valve 404 that controls the flow rate of carbon dioxide. A temperature regulator 406 is attached around the high-pressure vessel 405. Carbon dioxide introduced into the high-pressure vessel 405 is discharged from the discharge port 408. Here, the carbon dioxide that has been vaporized and discharged is recovered and regenerated as liquefied carbon dioxide so that it can be reused, and measures are taken to prevent the influence on the environment.

  The discharge amount of carbon dioxide is controlled by a valve 407. The pressure in the high-pressure vessel 405 can be changed by controlling the carbon dioxide introduction valve 404 and the discharge valve 407. The exposed substrate 409 was fixed and sealed in a high-pressure vessel 405 having a temperature of 36 ° C. (this temperature was used as a temperature near the critical temperature of 31 ° C.). Thereafter, the high-pressure pump 402 was operated, the valve 404 was opened, and carbon dioxide was introduced into the high-pressure vessel 405 at a flow rate of 400 ml / min. At this time, the pressure in the high-pressure vessel is set by making the introduction amount excessive compared to the discharge amount while discharging carbon dioxide from the vessel.

After the inside of the container was raised to 200 atm and developed for 2 minutes, the pressure was reduced to 73 atm while maintaining the inside of the developing container at 36 ° C., and rinsed for 5 minutes. Note that the pressure reduction reduced the injection amount from the introduction valve 404 and increased the discharge amount from the discharge valve 407 to 73 atm. In addition, a new fluid was introduced into the rinse, and the used fluid was discharged from the high-pressure vessel. After rinsing, the introduction valve 404 was closed, carbon dioxide was discharged at a flow rate of 1 liter / min while maintaining 36 ° C., and the pressure was reduced to atmospheric pressure. After the above development processing, the residual film thickness in the exposed area was measured. When the electron beam sensitivity was determined from the relationship between the residual film thickness and the exposure dose, a high sensitivity of ² μC / cm ² was obtained.

Using an electron beam drawing apparatus (acceleration voltage of electron beam is 75 kV) on a substrate coated with the pattern forming material of the present invention with a film thickness of 0.15 μm, a line and space pattern of 0.1 μm at an irradiation dose of 12 μC / cm ^2. Drawn. As a result of developing in the same process as described above, a pattern having a dimension could be formed without pattern collapse, and the variation in line width (3σ) was 8.5 nm.

(Embodiment 1)
FIG. 5 shows an embodiment in which the radiation-sensitive composition and pattern forming method of the present invention are applied to a process of processing an interlayer insulating film of a silicon semiconductor using an electron beam drawing technique.

First, a field insulating film 502 for element isolation made of SiO ₂ is provided on a semiconductor substrate 501 made of p-type silicon single crystal. In an active region (not shown) surrounded by the field insulating film 502, a semiconductor element such as a MOS transistor or a bipolar transistor is provided. A first layer aluminum wiring 503 is patterned on the field insulating film 502, and an interlayer insulating film 504 is further provided on the aluminum wiring 503. This interlayer insulating film 504 is made of, for example, SiO ₂ . On the layer insulating film 504, a coating film 505 of the radiation-sensitive composition of the present invention (Example 1) is formed (FIG. 5A).

  Next, an electron beam 506 is irradiated at a predetermined position to form a latent image on the resist film 505, and then heat treated at 90 ° C. for 2 minutes to increase the solubility of the latent image portion of the resist in an alkaline aqueous solution. The reaction was accelerated (FIG. 5 (b)). After the above heat treatment, development was performed by immersing in an aqueous solution containing 1.2% by weight of TMAH for 60 seconds to form a resist pattern 507 (FIG. 5C).

  Next, the interlayer insulating film 504 is etched using the resist film 507 as a mask, and then the resist film 507 is removed, whereby conduction between the first layer aluminum wiring 503 and the second layer aluminum wiring formed in the next process is achieved. A through hole 508 for taking was formed.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention is applied to the manufacture of electronic devices such as semiconductor integrated circuits, optical disks, and hard disks, and can be used particularly in a lithography process for forming fine patterns with high accuracy.

It is process drawing of the process of a supercritical fluid development type resist. It is a relationship diagram of time and pressure in a resist development process using a supercritical fluid according to the present invention. It is a molecular weight distribution map of the polynuclear phenol of the present invention. 1 is a configuration diagram of a resist developing apparatus according to an embodiment of the present invention. (A)-(d) is process sectional drawing for demonstrating embodiment of this invention.

Explanation of symbols

401 High-pressure carbon dioxide gas container 402 High-pressure pump 403 Piping 404 Flow control valve 405 High-pressure container 406 Temperature regulator 407 Discharge control valve 408 Discharge port 409 Substrate 501 Semiconductor substrate 502 Field insulating film 503 Aluminum wiring 504 Interlayer insulating film 505 Resist film 506 Electron beam 507 Resist pattern 508 after development Through hole

Claims (5)

A structure in which at least two polynuclear phenol compounds having 5 or more benzene rings and 5 or more hydroxyl groups and having 2 or less hydroxyl groups bonded to one benzene ring are bonded via an acid-decomposable group. A radiation-sensitive composition comprising a compound or resin as a main component, the molecular weight of which decreases by irradiation with radiation,
The radiation-sensitive composition according to claim 1, wherein the polynuclear phenol compound has a purity of 90% or more in terms of a peak area corresponding to the main component measured by gel permeation chromatography.   The polynuclear phenol compound has a structure in which 5 to 22 benzene rings are bonded to each other via one or more of methylene carbon, methine carbon, and quaternary carbon. Radiation sensitive composition. (A) The process of apply | coating the resist film which has a radiation sensitive composition as a main component on the board | substrate for electronic device manufacture,
(B) forming a latent image of a predetermined pattern by irradiating the resist film with radiation through a mask of a predetermined pattern;
(C) forming a resist film having a predetermined pattern on the substrate by developing the resist film on which the latent image having the predetermined pattern is formed;
(D) etching the substrate using the resist film of the predetermined pattern obtained in the step (c) as a mask,
In the radiation-sensitive composition, the polynuclear phenol compound having 5 or more benzene rings and 5 or more hydroxyl groups and having 2 or less hydroxyl groups bonded to one benzene ring is present at least via an acid-decomposable group. A radiation-sensitive composition comprising as a main component a compound or resin having a structure in which two or more are bonded, and having a molecular weight reduced by irradiation with radiation,
The purity of the polynuclear phenol compound is 90% or more in terms of the ratio of the peak area corresponding to the main component measured by gel permeation chromatography.   4. The method of manufacturing an electronic device according to claim 3, wherein the development in the step (c) is performed by exposing the resist film to a supercritical carbon dioxide atmosphere.   4. The method of manufacturing an electronic device according to claim 3, wherein the radiation is an electron beam, an X-ray, or extreme ultraviolet rays having a wavelength of 5 to 15 nm.

Images