WO2017169807A1 - レジストパターン形成方法及びレジスト - Google Patents
レジストパターン形成方法及びレジスト Download PDFInfo
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- WO2017169807A1 WO2017169807A1 PCT/JP2017/010518 JP2017010518W WO2017169807A1 WO 2017169807 A1 WO2017169807 A1 WO 2017169807A1 JP 2017010518 W JP2017010518 W JP 2017010518W WO 2017169807 A1 WO2017169807 A1 WO 2017169807A1
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- radiation
- resist
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- alkali
- resist pattern
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/038—Macromolecular compounds which are rendered insoluble or differentially wettable
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/20—Exposure; Apparatus therefor
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/38—Treatment before imagewise removal, e.g. prebaking
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- H10P76/00—
Definitions
- the present invention relates to a resist pattern forming method and a resist, and more particularly to a resist pattern forming method capable of forming a resist pattern having a reverse tapered section, and a resist having a resist pattern having a reverse tapered section. .
- a resist material capable of forming a resist pattern having a reverse taper in cross section may be required.
- a pattern is formed by a lift-off method and a case where an electrically insulating partition wall of an organic EL display element is formed.
- a metal wiring material is deposited on the outermost surface and the bottom of the resist pattern having a reverse taper cross section. The resist pattern is removed together with the metal wiring material deposited on the surface.
- the cross section of the resist pattern is a reverse taper shape, it is possible to suppress the metal wiring material from being deposited on the side walls constituting the reverse taper shape when the metal wiring material is deposited.
- a wiring pattern made of a wiring material can be satisfactorily formed.
- the photoresist composition according to Patent Document 1 includes an alkali-soluble resin, two types of photoacid generators, a crosslinking agent, and a solvent. More specifically, two types of photoacid generators contained in such a photoresist composition are halogen-containing photoacids, one of which is likely to be distributed on top of a coating film obtained by applying a photoresist composition on a substrate. The other is a triazine photoacid generator that can improve the sensitivity of the photoresist composition in the exposure and development steps.
- the halogen-containing photoacid generator is unevenly distributed on the upper part of the coating, and a relatively large amount of acid is generated on the upper part of the coating by exposure or heat treatment to form a relatively large number of crosslinked structures on the upper part of the coating.
- a resist pattern having a good reverse taper shape could be formed.
- the process of depositing the metal wiring material on the resist pattern is generally performed in a high temperature environment. Therefore, the resist pattern is required to have excellent heat resistance. Therefore, conventionally, a radiation-sensitive resin composition that is excellent in heat resistance and capable of forming a resist pattern having a cross-section with a reverse taper has been proposed (for example, see Patent Document 2).
- the radiation sensitive resin composition by patent document 2 contains the specific alkali-soluble resin, the crosslinking component which bridge
- such a resin composition has realized high heat resistance by using a resin having a specific composition as an alkali-soluble resin.
- JP 2013-527940 A Japanese Patent Laid-Open No. 2005-316412
- the angle formed by the side walls constituting the reverse taper shape of the resist pattern with respect to the resist surface is made sharper, that is, the taper angle (the angle formed by the side walls) is made obtuse. is necessary.
- the photoresist composition disclosed in Patent Document 1 and the radiation-sensitive resin composition disclosed in Patent Document 2 a taper angle is sufficiently large, and a favorable reverse taper-shaped resist pattern is formed. There is room for improvement in terms of maintaining such a good reverse taper shape even in a high temperature environment.
- the present invention provides a resist pattern forming method capable of forming a resist pattern having a good reverse taper shape with a sufficiently large taper angle and capable of maintaining a good reverse taper shape even in a high temperature environment.
- Another object of the present invention is to provide a resist having a resist pattern having a good reverse taper shape with a sufficiently large taper angle and capable of maintaining a good reverse taper shape even in a high temperature environment. To do.
- the present inventors have intensively studied for the purpose of solving the above problems. Then, the present inventors blended a compound that absorbs a predetermined amount or more of active radiation with respect to the radiation-sensitive resin composition, and further, in forming a resist pattern using such a radiation-sensitive composition, By forming a resist pattern under a predetermined temperature condition, it is possible to form a resist pattern with a sufficiently large taper angle and a good reverse taper shape and maintain such a good reverse taper shape even in a high temperature environment. We have found that this is possible and have completed the present invention.
- the present invention aims to advantageously solve the above-mentioned problems, and the resist pattern forming method of the present invention comprises a preparation step for preparing a radiation-sensitive resin composition, and the above-mentioned sensitivity on a substrate.
- An application process for forming a coating film by applying and drying the radiation resin composition a first heat treatment process for heating the coating film at a first temperature, and a resist film obtained through the first heat treatment process
- the radiation-sensitive resin composition includes an exposure step of irradiating actinic radiation, and a second heat treatment step of maintaining the resist film under a second temperature condition after the start of the exposure step.
- a crosslinking component (b) that crosslinks the alkali-soluble resin by irradiation with an alkali-soluble resin (a), actinic radiation, or irradiation with actinic radiation and subsequent heat treatment, and a compound (c) that absorbs the actinic radiation Contains (1)
- the crosslinking component (b) is a compound that generates an acid upon irradiation with the active radiation, and the alkali-soluble resin (with the acid generated by the active radiation as a catalyst).
- a) is a combination with a compound that crosslinks, and (2) the compound (c) that absorbs actinic radiation is more than 1.0 part by mass with respect to 100 parts by mass of the alkali-soluble resin (a), and The first temperature is equal to or higher than the second temperature.
- the radiation-sensitive resin composition containing more than 1.0 parts by mass of the compound (c) that absorbs active radiation with respect to 100 parts by mass of the alkali-soluble resin (a). If the resist pattern is formed by setting the first temperature, which is the heating temperature, to be equal to or higher than the second temperature in the second heat treatment step after the start of the exposure step, a good reverse taper shape can be obtained, and good in a high temperature environment.
- reverse taper shape means that the open area on the resist surface is larger than the open area on the resist bottom in addition to the standard taper shape constituted by the surface inclined toward the apex of the taper. Including small, overhang-shaped structures.
- the radiation-sensitive resin composition further contains a basic compound (d). This is because, if the radiation-sensitive resin composition contains a basic compound, the allowable range for the second temperature variation can be expanded, and the flexibility of the resist pattern forming method can be improved.
- Resist of this invention is alkali-soluble resin (a), irradiation of actinic radiation, or irradiation of actinic radiation, and heat processing after that.
- a radiation-sensitive resin composition containing a crosslinking component (b) for crosslinking the alkali-soluble resin and a compound (c) that absorbs the actinic radiation, wherein (1) the crosslinking component (b) It is a combination of a compound that generates an acid upon irradiation with the actinic radiation and a compound that crosslinks the alkali-soluble resin (a) using the acid generated by the actinic radiation as a catalyst, and (2) a compound that absorbs the actinic radiation (C) is formed using a radiation-sensitive resin composition containing more than 1.0 part by mass with respect to 100 parts by mass of the alkali-soluble resin (a).
- the ratio Wb / Wt of the line width Wt on the exposed surface to the line width Wb on the non-exposed surface is less than 0.7, and a 120 ° C.
- the angle formed by the side wall of the line constituting the inversely tapered shape of the resist pattern after heating for 1 minute under a temperature condition is less than 90 °.
- Such a resist has a good taper shape and excellent heat resistance.
- the present invention it is possible to form a resist pattern that has a good reverse taper shape and that can maintain such a good reverse taper shape even in a high temperature environment.
- ADVANTAGE OF THE INVENTION According to this invention, while having a reverse taper shape favorable, the resist which has a resist pattern excellent in heat resistance can be provided.
- the resist pattern forming method of the present invention can be used when a semiconductor device manufacturing process or an electrically insulating partition wall of an organic EL display element is formed.
- the resist pattern forming method of the present invention relates to a resist pattern having a reverse taper shape, and the resist of the present invention can be formed by the resist pattern forming method of the present invention.
- the resist pattern forming method of the present invention includes a preparation step of preparing a radiation-sensitive resin composition, a coating step of coating and drying the resin composition on a substrate to form a coating film, A first heat treatment step for heating at a temperature; an exposure step for irradiating active radiation to the resist film obtained through the first heat treatment step; and after the start of the exposure step, the resist film is subjected to a second temperature condition. And a second heat treatment step to be held.
- the radiation-sensitive resin composition prepared in the preparation step includes an alkali-soluble resin (a), a crosslinking component (b) that crosslinks the alkali-soluble resin by irradiation with actinic radiation, or irradiation with actinic radiation and subsequent heat treatment, and Contains compound (c) that absorbs actinic radiation.
- the crosslinking component (b) is a combination of a compound that generates an acid upon irradiation with actinic radiation and a compound that crosslinks an alkali-soluble resin using the acid generated by the actinic radiation as a catalyst.
- a resin composition contains more than 1.0 mass part of compounds (c) which absorb actinic radiation with respect to 100 mass parts of alkali-soluble resin (a).
- the resist pattern forming method of the present invention may include a developing step of developing the resist film that has undergone the second heat treatment step.
- the resist pattern forming method of the present invention is characterized in that the first temperature (so-called pre-bake temperature) is equal to or higher than the second temperature (so-called post-bake temperature).
- the heating temperature in the first heat treatment step before the exposure step is set to be equal to or higher than the second temperature in the second heat treatment step after the start of the exposure step.
- a reverse taper shape is good, and a resist pattern that can maintain such a good reverse taper shape even in a high temperature environment can be formed. The reason is not clear, but it is assumed that it is as follows.
- the heating temperature in the first heat treatment step before the exposure step is generally lower than the heating temperature in the second heat treatment step after the exposure treatment. This was to increase the exposure amount in the exposure step and to increase the definition of the resulting resist pattern without reducing the resist sensitivity.
- the compounding amount of the compound (c) that absorbs active radiation is 1.0 part by mass with respect to 100 parts by mass of the alkali-soluble resin (a). It is characterized by being super and more than conventional. If the compounding amount of the compound (c) that absorbs actinic radiation is large, the probability that the compound (c) is unevenly distributed without being uniformly dispersed in the coating film formed using the resin composition in the coating process may be increased. is assumed.
- a coating film formed using a resin composition containing a large amount of compound (c) is heat-treated at a pre-baking temperature equal to or higher than the post-baking temperature, so that a high content of compound (c) is uniform. It is presumed that a resist film dispersed in can be formed. Furthermore, the pre-bake temperature is set to be higher than the post-bake temperature, in other words, the post-bake temperature is not higher than the pre-bake temperature, so that various components uniformly dispersed in the resist film by the post-bake are dispersed in the resist film. It is presumed that the state is maintained, and as a result, a good reverse taper shape can be formed.
- each process included in the resist pattern forming method of the present invention will be described.
- the radiation-sensitive resin composition includes an alkali-soluble resin (a), a crosslinking component (b), and a compound (c) that absorbs active radiation, and optionally further includes a basic compound (d) and other components.
- the radiation sensitive resin composition can be obtained, for example, by mixing the components (a) to (d).
- the obtained radiation-sensitive resin composition can be used for the coating process as it is.
- the radiation-sensitive resin composition solution can be prepared by adding and dissolving the components (a) to (d) in a solvent and optionally performing a filtration treatment or the like.
- the radiation-sensitive resin composition (hereinafter also simply referred to as “resin composition”) used in the resist pattern forming method of the present invention is an alkali-soluble resin (a), irradiation with actinic radiation, or irradiation with actinic radiation and thereafter By the heat treatment, a crosslinking component (b) for crosslinking the alkali-soluble resin and a compound (c) for absorbing actinic radiation are contained. Further, in the resin composition, the crosslinking component (b) is a combination of a compound that generates an acid upon irradiation with actinic radiation and a compound that crosslinks an alkali-soluble resin using the acid generated by the actinic radiation as a catalyst.
- the resin composition is characterized by containing more than 1.0 part by mass of the compound (c) that absorbs actinic radiation with respect to 100 parts by mass of the alkali-soluble resin (a).
- the resin composition contains a compound (c) in an amount exceeding 1.0 part by mass, thereby forming a good reverse taper-shaped resist pattern and maintaining such a good reverse taper shape even in a high temperature environment. it can. The reason is not clear, but it is assumed that it is as follows.
- the compound (c) that absorbs actinic radiation irradiates the resist film obtained by applying the resin composition on the substrate when the resist composition having a resist pattern is formed using the resin composition. It functions to absorb actinic radiation in the exposure process. Accordingly, a gradient is formed in the dose of active radiation that reaches from the side closer to the exposure surface in the thickness direction of the resist film toward the surface opposite to the exposure surface of the resist film. Specifically, the dose that reaches the side closer to the exposure surface increases, and the dose that reaches the lower surface as the surface approaches the surface opposite to the exposure surface decreases.
- the resin composition contains, as a crosslinking component (b), a compound that generates an acid upon irradiation with actinic radiation and a compound that crosslinks an alkali-soluble resin using an acid generated by actinic radiation as a catalyst.
- a crosslinking component (b) a compound that generates an acid upon irradiation with actinic radiation and a compound that crosslinks an alkali-soluble resin using an acid generated by actinic radiation as a catalyst.
- the content rate of the compound (c) in a resin composition was more than 1.0 mass part with respect to 100 mass parts of alkali-soluble resin (a).
- Such a content ratio is higher than the content ratio that has been conventionally employed for compounds that absorb actinic radiation.
- the cross-linking formation in the vicinity of the exposed surface of the resist is stronger than the bottom of the resist, even if the resist is placed in a high temperature environment, the heat effect at the bottom of the resist is more robust in the cross-linking formation. Since it can be compensated by the resist in the vicinity of the exposed surface, it is presumed that as a result, a good reverse taper shape can be maintained even in a high temperature environment. Furthermore, since the resist formed using the resin composition has a stronger cross-linked structure near the exposed surface of the resist than the cross-linked structure near the bottom of the resist, it occurs near the bottom of the resist in a high temperature environment. It is assumed that the distortion can be compensated by the resist near the exposure surface. In the present specification, the “angle formed by the side wall with respect to the resist surface” refers to an acute angle formed by the side wall forming the inverse tapered structure and the resist surface.
- the alkali-soluble resin is not particularly limited, and an alkali-soluble resin that can be generally used for forming a resist can be used.
- the “alkali-soluble resin” is a resin having solubility in a developer, particularly preferably an alkali developer, used in a development processing step of a negative photosensitive resin composition containing the component. Note that “having solubility in an alkali developer” means that a transparent mixed solution can be obtained visually when the alkali developer and the resin solution are mixed.
- alkali-soluble refers to a resin having an insoluble content of less than 0.1 mass% when dissolved in a solution having a pH of 8 or higher.
- the alkali-soluble resin include novolak resin, polyvinyl phenol resin, polyvinyl alcohol resin, resol resin, acrylic resin, styrene-acrylic acid copolymer resin, hydroxystyrene polymer resin, polyvinyl hydroxybenzoate, and mixed resins thereof. Etc. Among these, it is preferable to use the novolac resin alone or in combination with other resins.
- novolak resin a commercially available novolak resin or a novolak resin obtained by reacting phenols with aldehydes or ketones in the presence of an acidic catalyst (for example, oxalic acid) can be used.
- an acidic catalyst for example, oxalic acid
- phenols examples include phenol, orthocresol, metacresol, paracresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4- Dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, 2-methylresorcinol 4-methylresorcinol, 5-methylresorcinol, 4-t-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 2- Me Carboxymethyl-5-methylphenol, 2-t-butyl-5-methylphenol, thymol, and the like Isochimoru. These can be used alone or in combination of two or more.
- aldehydes include formaldehyde, formalin, paraformaldehyde, trioxane, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, ⁇ -phenylpropylaldehyde, ⁇ -phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p- Hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde, terephthalaldehyde, etc. It is done.
- ketones include acetone, ace
- a novolak resin by using metacresol and paracresol together and subjecting these to formaldehyde, formalin or paraformaldehyde for condensation reaction.
- the charging ratio of metacresol to paracresol is usually 80:20 to 20:80, preferably 70:30 to 40:60, based on mass.
- the average molecular weight of the novolak resin is a weight average molecular weight in terms of monodisperse polystyrene measured by gel permeation chromatography (Gel Permeation Chromatography: GPC), and is usually 1000 or more, preferably 2000 or more, more preferably 2500 or more, usually 10,000. Hereinafter, it is preferably 7000 or less, more preferably 6000 or less.
- GPC Gel Permeation Chromatography
- polyvinylphenol resin examples include a homopolymer of vinyl phenol and a copolymer of vinyl phenol and a monomer copolymerizable therewith.
- the monomer copolymerizable with the vinylphenol resin examples include isopropenylphenol, acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, and vinyl acetate.
- a homopolymer of vinylphenol is preferable, and a homopolymer of p-vinylphenol is more preferable.
- the average molecular weight of the polyvinyl phenol resin is a weight average molecular weight (Mw) in terms of monodisperse polystyrene measured by GPC, and is usually 1000 or more, preferably 1500 or more, more preferably 2000 or more, usually 20000 or less, preferably 10,000 or less. Preferably it is 15000 or less. If the weight average molecular weight of the polyvinylphenol resin is not less than the above lower limit, when a crosslinking reaction occurs in the exposed portion of the resist film, a sufficient molecular weight increasing effect can be obtained, and the exposed portion is insoluble in the developer. It can be raised enough. If the weight average molecular weight of polyvinylphenol is not more than the above upper limit value, a sufficient resist pattern can be obtained by ensuring a sufficient difference in solubility in an alkaline developer between an exposed area and an unexposed area in the resist.
- Mw weight average molecular weight
- the weight average molecular weights of the novolac resin and the polyvinylphenol resin can be controlled within a desired range by adjusting the synthesis conditions.
- the weight average molecular weight of each resin can be adjusted by adjusting the amount of reaction raw material added during the production of the novolak resin or polyvinylphenol resin. More specifically, the weight average molecular weight of the resulting novolak resin can be increased by increasing the amount of formaldehyde, formalin or paraformaldehyde added for the condensation reaction.
- the weight average molecular weight of the obtained polyvinylphenol resin can be increased by reducing the amount of the polymerization initiator added during polymerization of the polyvinylphenol resin.
- the weight average molecular weight of each resin obtained can be increased by increasing the reaction time during synthesis of the novolak resin or the polyvinylphenol resin.
- a method of pulverizing a resin obtained by synthesis or a commercially available resin, and solid-liquid extraction with an organic solvent having an appropriate solubility (2) a resin obtained by synthesis or a commercially available resin Can be dissolved in a good solvent and dropped into a poor solvent, or the weight average molecular weight can be controlled by a method of solid-liquid or liquid-liquid extraction by dropping a poor solvent.
- a crosslinking component is a component which bridge
- the crosslinking component (b) includes a compound that generates an acid upon irradiation with actinic radiation (hereinafter also referred to as “photoacid generator”) and a compound that crosslinks an alkali-soluble resin using an acid generated by light as a catalyst (acid-sensitive substance). : Hereinafter referred to as “acid crosslinking agent”). Both of these compounds are preferred in that they are excellent in compatibility with alkali-soluble resins and can provide a cross-linked chemically amplified resist having good sensitivity when combined with alkali-soluble resins.
- the photoacid generator which is a compound that generates an acid by actinic radiation is not particularly limited as long as it is a substance that generates a Bronsted acid or a Lewis acid when irradiated with actinic radiation, and is an onium salt or a halogenated organic compound.
- Known compounds such as quinonediazide compounds, sulfone compounds, organic acid ester compounds, organic acid amide compounds, and organic acid imide compounds can be used.
- These photoacid generators are preferably selected from the viewpoint of spectral sensitivity in accordance with the wavelength of the light source that exposes the pattern.
- onium salts include diazonium salts, ammonium salts, iodonium salts such as diphenyliodonium triflate, sulfonium salts such as triphenylsulfonium triflate, phosphonium salts, arsonium salts, and oxonium salts.
- Halogenated organic compounds include halogen-containing oxadiazole compounds, halogen-containing triazine compounds, halogen-containing acetophenone compounds, halogen-containing benzophenone compounds, halogen-containing sulfoxide compounds, halogen-containing sulfone compounds, halogen-containing thiazole compounds.
- halogenated organic compound examples include tris (2,3-dibromopropyl) phosphate, tris (2,3-dibromo-3-chloropropyl) phosphate, tetrabromochlorobutane, 2- [2- (3,4 -Dimethoxyphenyl) ethenyl] -4,6-bis (trichloromethyl) -S-triazine, 2- [2- (4-methoxyphenyl) ethenyl] -4,6-bis (trichloromethyl) -S-triazine, hexa Chlorobenzene, hexabromobenzene, hexabromocyclododecane, hexabromocyclododecene, hexabromobiphenyl, allyltribromophenyl ether, tetrachlorobisphenol A, tetrabromobisphenol A, bis (ch
- quinonediazide compound examples include 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,1 Sulfonic acid esters of quinonediazide derivatives such as naphthoquinonediazide-4-sulfonic acid ester, 2,1-benzoquinonediazide-5-sulfonic acid ester; 1,2-benzoquinone-2-diazide-4-sulfonic acid chloride, 1, 2-naphthoquinone-2-diazide-4-sulfonic acid chloride, 1,2-naphthoquinone-2-diazide-5-sulfonic acid chloride, 1,2-naphthoquinone-1-diazide-6-sulfonic acid chloride, 1,2- Benzoquinone-1-d
- sulfone compound examples include sulfone compounds and disulfone compounds having an unsubstituted, symmetrically or asymmetrically substituted alkyl group, alkenyl group, aralkyl group, aromatic group, or heterocyclic group.
- organic acid esters include carboxylic acid esters, sulfonic acid esters, and phosphoric acid esters.
- Organic acid amides include carboxylic acid amides, sulfonic acid amides, phosphoric acid amides, and the like. Examples thereof include carboxylic acid imide, sulfonic acid imide, and phosphoric acid imide.
- cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate dicyclohexyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, 2-oxocyclohexyl (2-norbornyl) sulfonium trifluoromethanesulfonate, 2-cyclohexylsulfonylcyclohexanone Dimethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, N-hydroxysuccinimide trifluoromethanesulfonate, phenylparatoluenesulfonate, and the like.
- the photoacid generator is usually in a proportion of 0.1 to 10 parts by weight, preferably 0.3 to 8 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the alkali-soluble resin (a). Used in. If the ratio of the photoacid generator is too small or too large, the shape of the resist pattern may be deteriorated.
- An acid crosslinking agent is a compound (acid-sensitive substance) that can crosslink an alkali-soluble resin in the presence of an acid generated by irradiation (exposure) with actinic radiation.
- acid cross-linking agents include known acid cross-linking compounds such as alkoxymethylated urea resins, alkoxymethylated melamine resins, alkoxymethylated uron resins, alkoxymethylated glycoluril resins, and alkoxymethylated amino resins. Can be mentioned.
- acid crosslinking agents include alkyl etherified melamine resins, benzoguanamine resins, alkyl etherified benzoguanamine resins, urea resins, alkyl etherified urea resins, urethane-formaldehyde resins, resol type phenol formaldehyde resins, alkyl etherified resole type phenol formaldehydes. Examples thereof include resins and epoxy resins.
- the acid crosslinking agent is preferably a resin having a weight average molecular weight of 300 or more.
- alkoxymethylated melamine resins are preferable, and specific examples thereof include methoxymethylated melamine resins, ethoxymethylated melamine resins, n-propoxymethylated melamine resins, and n-butoxymethylated melamine resins. it can.
- a methoxymethylated melamine resin such as hexamethoxymethylmelamine is particularly preferable in terms of good resolution.
- alkoxymethylated melamine resins include, for example, PL-1170, PL-1174, UFR65, CYMEL (registered trademark) 300, CYMEL (registered trademark) 303 (above, manufactured by Mitsui Cytec), BX-4000, Nicarak MW-30 and MX290 (manufactured by Sanwa Chemical Co., Ltd.).
- the acid crosslinking agent may be blended in an amount of usually 0.5 to 60 parts by mass, preferably 1 to 50 parts by mass, more preferably 2 to 40 parts by mass with respect to 100 parts by mass of the alkali-soluble resin (a). preferable. If the blending amount of the acid crosslinking agent is not less than the above lower limit value, the crosslinking reaction is sufficiently advanced to reduce the residual film ratio of the resist pattern after development using an alkali developer, or the resist pattern is swollen or meandered. It is possible to avoid the occurrence of such deformation. If the compounding amount of the acid crosslinking agent is not more than the above upper limit, the resulting resist pattern can have high resolution.
- the compound (c) that absorbs actinic radiation absorbs actinic radiation irradiated to the resist film.
- a reverse taper-shaped resist pattern can be formed.
- the shape of the resist pattern can also be affected by the fact that the active radiation applied to the resist film is reflected by the substrate, the ITO film formed on the substrate, etc. through the resist film. Therefore, the shape of the resist pattern can be favorably controlled by absorbing the active radiation reflected by the compound (c) contained in the resin composition.
- a resin composition using a combination of a photoacid generator and an acid crosslinking agent as a crosslinking component is a cross-linked chemical amplification resist, and the acid generated by light irradiation diffuses in the resist film, and light is emitted. Since the cross-linking reaction is caused to a non-contact region, the presence of the compound (c) that absorbs active radiation makes it possible to satisfactorily control the shape of the resist pattern.
- “absorbing actinic radiation” means having at least one maximum absorption wavelength ⁇ max in any wavelength range of 13.5 nm to 450 nm.
- Examples of the compound (c) that absorbs actinic radiation include bisazide compounds, azo dyes, methine dyes, azomethine dyes, natural compounds such as curcumin and xanthone, cyanovinylstyrene compounds, 1-cyano-2- (4-dialkyl) Aminophenyl) ethylenes, p- (halogen-substituted phenylazo) -dialkylaminobenzenes, 1-alkoxy-4- (4′-N, N-dialkylaminophenylazo) benzenes, dialkylamino compounds, 1,2-dicyano Ethylene, 9-cyanoanthracene, 9-anthrylmethylenemalononitrile, N-ethyl-3-carbazolylmethylenemalononitrile, 2- (3,3-dicyano-2-propenylidene) -3-methyl-1,3- Examples include thiazoline.
- the compound (c) it is preferable to use a bisazide compound having an azide group at both ends. Furthermore, it is particularly preferable to use a bisazide compound that absorbs actinic radiation in the wavelength region of 200 to 500 nm.
- bisazide compound examples include 4,4′-diazidochalcone, 2,6-bis (4′-azidobenzal) cyclohexanone, 2,6-bis (4′-azidobenzal) -4-methylcyclohexanone, 2,6- Bis (4'-azidobenzal) -4-ethylcyclohexanone, sodium 4,4'-diazidostilbene-2,2'-disulfonate, 4,4'-diazidodiphenyl sulfide, 4,4'-diazidobenzophenone, 4,4'-diazidodiphenyl, 2,7-diazidofluorene, 4,4'-diazidophenylmethane.
- the resin composition contains the compound (c) in an amount of more than 1 part by weight, preferably 1.2 parts by weight or more, more preferably 1.5 parts by weight or more with respect to 100 parts by weight of the alkali-soluble resin (a). More preferably 1.8 parts by weight or more, usually 10.0 parts by weight or less, preferably 8.0 parts by weight or less, more preferably 5.0 parts by weight or less, and even more preferably 3.5 parts by weight or less. Including. If the compounding amount of the compound (c) in the resin composition is more than 1 part by mass with respect to 100 parts by mass of the alkali-soluble resin (a), the resist formed using the resin composition has a good reverse taper shape.
- the heat resistance of the resist formed using the resin composition can be further improved by setting the compounding amount of the compound (c) to the upper limit value or less. Furthermore, in general, when the resist film thickness is large, actinic radiation hardly penetrates the resist film, so that the compounding amount of the compound (c) may be relatively small. preferable.
- a basic compound is blended with the resin composition.
- the basic compound means a compound capable of capturing an acid derived from a photoacid generator. This is because if the basic compound is blended, the storage stability of the resin composition can be improved and the temperature tolerance range (PEB temperature margin) of the heat treatment temperature in the second heat treatment step can be expanded. Since the temperature tolerance range of the heat treatment temperature in the second heat treatment step is expanded, manufacturing variations of the resist pattern can be suppressed, so that the flexibility of the resist pattern forming method of the present invention can be enhanced.
- the basic compound (d) include inorganic basic compounds and organic basic compounds.
- an organic basic compound is more preferable because of its high solubility in an organic solvent. This is because the uniformity of the coating film formed by applying the resin composition solution on the substrate can be improved.
- the organic basic compound include nitrogen-containing basic compounds, organic halides, alkoxides, phosphazene derivatives, and Verkade bases. Among these, as the basic compound, it is preferable to use a nitrogen-containing basic compound. This is because the storage stability of the resin composition can be improved.
- nitrogen-containing basic compounds include aliphatic primary amines, aliphatic secondary amines, aliphatic tertiary amines, amino alcohols, aromatic amines, quaternary ammonium hydroxides, and alicyclic amines. Is mentioned.
- an aliphatic primary amine, an aliphatic secondary amine, and an aliphatic tertiary amine are blended as the nitrogen-containing basic compound.
- nitrogen-containing basic compound examples include butylamine, hexylamine, ethanolamine, diethanolamine, triethanolamine, 2-ethylhexylamine, 2-ethylhexyloxypropylamine, methoxypropylamine, diethylaminopropylamine, N-methylaniline, N-ethylaniline, N-propylaniline, dimethyl-N-methylaniline, diethyl-N-methylaniline, diisopropyl-N-dimethylaniline, N-methylaminophenol, N-ethylaminophenol, N, N-dimethylaniline, N, N-diethylaniline, N, N-dimethylaminophenol, tetrabutylammonium hydroxide, tetramethylammonium hydroxide, 1,8-diazabicyclo [5.4.0] unde 7-ene, 1,5-diazabicyclo [4.3.0] non-5-ene, and the like
- the basic compound (d) is preferably a basic compound having a relatively high boiling point.
- the basic compound (d) preferably has a boiling point of 60 ° C. or higher, more preferably 100 ° C. or higher, further preferably 150 ° C. or higher, and usually 500 ° C. or lower. is there. If the boiling point of the basic compound (d) is high, volatilization in the first heat treatment step and the second heat treatment step, which will be described later, decreases, and the basic compound (d) remains in the obtained resist film after the post-exposure baking step. The amount is close to the blending ratio of the basic compound (d) in the resin composition.
- the boiling point of the basic compound is determined by the heat treatment temperature in the first heat treatment step (hereinafter also referred to as “pre-bake temperature”) and the heat treatment temperature in the second heat treatment step (hereinafter also referred to as “post-exposure bake temperature”). It is preferably 10 ° C. or higher, more preferably 30 ° C. or higher, and even more preferably 50 ° C. or higher. Furthermore, the basic compound is preferably a compound having a weight average molecular weight of less than 300.
- the basic compound (d) is usually 0.001 to 10 parts by weight, preferably 0.005 to 8 parts by weight, more preferably 0.005 parts by weight with respect to 100 parts by weight of the alkali-soluble resin (a). It can be contained in an amount of 01 to 5 parts by mass. If content of a basic compound (d) is more than the said lower limit, the storage stability of a resin composition can be improved and a PEB temperature margin can be expanded. Furthermore, when the content of the basic compound (d) exceeds the above upper limit value, the effect of improving storage stability is saturated and the resist characteristics may be adversely affected.
- the compounding amount of the basic compound (d) in the resin composition is preferably 0.001 times or more, more preferably 0.050 times or more, more preferably 0.200 times the compounding amount of the photoacid generator on a mass basis.
- the above is more preferable, less than 3.500 times is preferable, less than 2.000 times is more preferable, and less than 0.500 times is more preferable.
- the compounding quantity of a basic compound (d) below the said upper limit, it can avoid inhibiting the progress of a crosslinking reaction by excessively neutralizing the acid produced by exposure. Thereby, the reverse taper shape of the resist pattern formed using the resin composition can be made favorable. Moreover, the sensitivity of the resist formed using the resin composition can be improved by making the compounding quantity of a basic compound (d) below into the said upper limit.
- a surfactant can be optionally added to the resin composition.
- the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenol ether, and other polyoxyethylene alkyl ethers.
- Oxyethylene aryl ethers such as polyethylene glycol dilaurate and ethylene glycol distearate; EFTOP EF301, EF303, EF352 (manufactured by Shin-Akita Kasei), Megafax F171, F172, F173, F177 (Dainippon) Ink), Florard FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, S Fluorosurfactants such as C-101, SC-102, SC-103, SC-104, SC-105, SC-106 (Asahi Glass Co., Ltd.); Organosiloxane polymer KP341 (Shin-Etsu Chemical Co., Ltd.); Acrylic acid type Or methacrylic acid (co) polymer polyflow No.
- the compounding amount of these surfactants is usually 2 parts by mass or less, preferably 1 part by mass or less, per 100 parts by mass of the solid content of the resin composition.
- solvent An organic solvent is preferably used as a solvent for dissolving the above-described components.
- the organic solvent is used in an amount sufficient to uniformly dissolve or disperse each component as described above.
- the solid content concentration in the resin composition solution is usually about 5 to 50% by mass, preferably about 10 to 40% by mass.
- organic solvent examples include alcohols such as n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, and cyclohexyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; propyl formate, Esters such as butyl formate, ethyl acetate, propyl acetate, butyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, ethyl ethoxypropionate, ethyl pyruvate; tetrahydrofuran, Cyclic ethers such as dioxane; cellosolves such as methyl cellosolve, ethyl cellosolve, butyl
- the resin composition obtained in the preparation step is coated on a substrate and dried to form a coating film.
- the substrate is not particularly limited as long as it is a general substrate that can be used as a semiconductor substrate, and may be, for example, a silicon substrate, a glass substrate, an ITO film formation substrate, a chromium film formation substrate, or a resin substrate.
- a general coating method such as spin coating, spraying, brush coating, or dip coating can be employed.
- the coating film formed in the coating step is heated at a first temperature.
- the pre-baking temperature that is the first temperature is preferably higher than the post-baking temperature that is the second temperature, more preferably 5 ° C. or more, and even more preferably 10 ° C. or more. If the pre-baking temperature is higher than the post-baking temperature, the reverse taper shape of the resulting resist pattern can be made better, and such a good reverse taper shape can be better maintained even in a high temperature environment.
- the pre-bake temperature, which is the first temperature is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 105 ° C. or higher, preferably 130 ° C.
- the time for the first heat treatment step may be 10 seconds or more and 200 seconds or less.
- the first heat treatment step is not particularly limited, and can be performed by placing a substrate on which a coating film is formed on a heating mechanism such as a hot plate provided in a general baking apparatus, The pre-baking temperature can be controlled by changing the set temperature of the hot plate. And the film thickness of the resist film obtained through the 1st heat processing process is 0.1 to 15 micrometer normally.
- the resist film obtained through the first heat treatment step is irradiated with actinic radiation.
- the active radiation has a wavelength of 13.5 nm or more and 450 nm or less, and specifically includes ultraviolet rays, far ultraviolet rays, excimer laser light, X-rays, electron beams, extreme ultraviolet light (Extreme Ultra Violet), and the like.
- the exposure light source is not particularly limited as long as it is a light source capable of irradiating actinic radiation.
- an ultraviolet light source for example, an ultraviolet light source, a semiconductor laser irradiation device, a metal halide lamp, a high-pressure mercury lamp, an excimer laser (KrF, ArF, F2)
- Examples include an irradiation apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, and an EUV exposure apparatus.
- the exposure amount is usually 10 mJ / cm 2 or more and 2000 mJ / cm 2 or less
- the exposure time is usually 1 second or more and 180 seconds or less.
- the resist film after the start of the exposure step is held under the second temperature condition.
- the second heat treatment step can be performed by the same apparatus as the first heat treatment step.
- the sample stage of the exposure device is a hot plate-like one. It preferably has a function.
- the second temperature is not higher than the first temperature, preferably 20 ° C. or higher, more preferably 80 ° C. or higher, usually 130 ° C. or lower, preferably 120 ° C.
- the time for the second heat treatment step is usually 10 seconds or longer, preferably 60 seconds or longer, more preferably 100 seconds or longer, and usually 200 seconds or shorter.
- the cross-linking reaction of the cross-linking component (b) can be promoted by maintaining the resist film that has undergone the exposure step under the second temperature condition.
- the resist film is “heated” in the second heat treatment step. Instead, it may be held for a predetermined time in an atmosphere of about room temperature (for example, 25 ° C.).
- the resist pattern is developed using an alkaline developer by a general development method such as paddle development, spray development, and dip development.
- the alkaline developer used in the development process may be an alkaline aqueous solution having a pH of 8 or higher.
- alkali examples include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate and ammonia; primary amines such as ethylamine and propylamine; secondary amines such as diethylamine and dipropylamine; trimethylamine and triethylamine Tertiary amines such as; alcohol amines such as diethylethanolamine and triethanolamine; quaternary such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide Ammonium hydroxides; and the like.
- inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate and ammonia
- primary amines such as ethylamine and propylamine
- secondary amines such as diethylamine and dipropylamine
- a water-soluble organic solvent such as methyl alcohol, ethyl alcohol, propyl alcohol, and ethylene glycol, a surfactant, a resin dissolution inhibitor, and the like can be added to the alkaline aqueous solution.
- a metal wiring material is vapor-deposited on the entire surface of the substrate to form various films such as a metal vapor deposition film. Thereafter, the resist pattern is removed together with the film formed thereon to leave a film such as a metal vapor deposition film formed on the substrate.
- an organic EL display element an organic EL material is vapor-deposited on the resist pattern obtained by development, and then a metal such as aluminum is vapor-deposited. In this case, the resist pattern is left without being removed.
- the resist of the present invention comprises an alkali-soluble resin (a), irradiation with actinic radiation, or a crosslinking component (b) that crosslinks the alkali-soluble resin by irradiation with actinic radiation and subsequent heat treatment, and a compound that absorbs actinic radiation ( a radiation-sensitive resin composition containing c), wherein (1) the crosslinking component (b) is a compound capable of generating an acid upon irradiation with actinic radiation and an alkali-soluble resin (catalyst) using the acid generated by the actinic radiation as a catalyst.
- Radiation sensitivity which is a combination with a compound that crosslinks a), and includes (2) compound (c) that absorbs actinic radiation in excess of 1.0 part by mass with respect to 100 parts by mass of alkali-soluble resin (a).
- the resist width is set to the line width Wb on the non-exposed surface.
- the ratio Wb / Wt of the line width Wt on the exposed surface is less than 0.7, preferably less than 0.6, and forms a reverse tapered shape of the resist pattern after heating for 1 minute at a temperature of 120 ° C. Is less than 90 ° with respect to the resist surface.
- Such a resist is obtained by the resist pattern forming method of the present invention, and has a resist pattern that has a sufficiently large taper angle and can maintain a good reverse taper shape even in a high temperature environment.
- a resist contains at least an alkali-soluble resin (a), a crosslinking component (b), and a compound (c) that absorbs active radiation, and optionally, a basic compound (d) and other compounds. Contains ingredients. Each component contained in the resist was contained in the radiation-sensitive resin composition, and a suitable abundance ratio thereof was a suitable abundance ratio of each component in the resin composition. The same. Further, in the resist, the alkali-soluble resin (a) exists in a state of being cross-linked with each other.
- the resist of the present invention can satisfactorily form a fine wiring pattern when used for forming a wiring pattern.
- the resist of the present invention is excellent in heat resistance, it can maintain a tapered shape even when the resist pattern is heated.
- the resist of the present invention is generally used for forming a wiring pattern by metal vapor deposition performed in a high temperature environment. In this case, a fine wiring pattern can be formed satisfactorily.
- ⁇ Reverse taper shape> For the resist pattern formed in the examples and comparative examples, consisting of lines (parts that remain undissolved after the development process) and spaces (parts in which the resist film dissolves and becomes voids in the development process), the resist film lower surface ( That is, the line width (bottom line width) on the substrate side) and the line width (top line width) on the upper surface of the resist film were measured under observation with a scanning electron microscope (SEM). The obtained bottom line width was divided by the top line width and evaluated according to the following criteria.
- the substrate on which the resist pattern was formed in Examples and Comparative Examples was further heated at 120 ° C. for 1 minute on a hot plate.
- the cross-sectional shape of the substrate on which the resist pattern was formed was observed using an SEM, the angle formed by the resist sidewalls constituting the inverse tapered shape with respect to the resist surface was measured, and the heat resistance was evaluated according to the following criteria. .
- this evaluation method it can be evaluated that a good reverse taper shape having a sufficiently large taper angle can be maintained after further heating after the development step. That is, it is possible to evaluate whether or not the formed resist pattern can maintain a good reverse taper shape even when it is heated by being subjected to a vapor deposition process of a metal wiring material or the like.
- Example 1 Preparation of radiation-sensitive resin composition solution (preparation process)> A novolak resin having a weight average molecular weight of 3000 obtained by dehydrating and condensing 70 parts of m-cresol and 30 parts of p-cresol with 19 parts of formaldehyde was used as the alkali-soluble resin (a).
- the radiation sensitive resin composition solution was apply
- a silicon wafer having a coating film on the surface was placed on a hot plate set at a first temperature (pre-baking temperature) of 110 ° C., and held for 90 seconds to perform a first heat treatment (pre-baking) step.
- the film thickness of the obtained resist film was 4 ⁇ m.
- the resist film was exposed with a parallel light mask aligner (manufactured by Canon, trade name “PLA501F”, ultraviolet light source, irradiation wavelength 365 nm to 436 nm) using a 20 ⁇ m line & space (L & S) pattern mask.
- the exposure amount was an exposure amount at which the ratio of the width of the line portion to the width of the space portion was 1: 1 (exposure process).
- the second temperature post-bake temperature
- a silicon wafer with a resist film was placed on the hot plate, and the second heat treatment (post-bake) process was performed by holding for 100 seconds .
- Example 2 A resist pattern was formed in the same manner as in Example 1 except that 0.5 parts of triethanolamine (TEOA) was further added as a basic compound (d) in preparing the radiation-sensitive resin composition solution.
- Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.
- Example 3 In preparing the radiation-sensitive resin composition solution, a resist pattern was formed in the same manner as in Example 1 except that the amount of compound (c) that absorbs active radiation was changed as shown in Table 1. Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.
- Example 5 In forming the resist pattern, the combination of the first temperature in the first heat treatment (pre-baking) step and the combination of the second temperature in the second heat treatment (post-baking) step was changed as shown in Table 1, respectively. In the same manner as in Example 1, a resist pattern was formed. Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.
- Example 3 In forming the resist pattern, the same procedure as in Example 1 was conducted except that the second temperature in the second heat treatment (post-baking) step was set higher than the first temperature in the first heat treatment (pre-baking) step. A resist pattern was formed. Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.
- Example 4 In forming the resist pattern, the first temperature in the first heat treatment (pre-baking) step and the second temperature in the second heat treatment (post-baking) step are set to the same temperature, and actinic radiation is absorbed. A resist pattern was formed in the same manner as in Example 1 except that the amount of compound (c) was changed to 1 part by mass. Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.
- the compound (c) was used in a resin composition containing more than 1.0 part by mass with respect to 100 parts by mass of the alkali-soluble resin (a), and the pre-baking temperature was higher than the post-baking temperature. It can be seen that a resist pattern having a reverse taper shape can be formed, and a good reverse taper shape can be maintained even in a high temperature environment.
- the present invention it is possible to form a resist pattern having a good reverse taper shape and further excellent heat resistance.
- the resist of the present invention has a good reverse taper shape of the resist pattern and is excellent in heat resistance.
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Abstract
Description
しかし、特許文献1に開示されたフォトレジスト組成物、及び特許文献2に開示された感放射線性樹脂組成物では、テーパー角度が十分に大きい、良好な逆テーパー形状のレジストパターンを形成するとともに、高温環境下でもかかる良好な逆テーパー形状を維持するという点に関して、改善の余地があった。
ここで、本明細書において、「逆テーパー形状」とは、テーパー頂点に向かって傾斜する面により構成される標準的なテーパー形状に加えて、レジスト表面における開放面積がレジスト底部における開放面積よりも小さい、オーバーハング形状の構造も含むものとする。
本発明によれば、逆テーパー形状が良好であると共に、耐熱性に優れるレジストパターンを有するレジストを提供することができる。
本発明のレジストパターン形成方法は、感放射線性樹脂組成物を調製する調製工程と、基板上に、樹脂組成物を塗布及び乾燥して塗膜を形成する塗布工程と、塗膜を第1の温度で加熱する第1熱処理工程と、第1熱処理工程を経て得られたレジスト膜に対して、活性放射線を照射する露光工程と、露光工程の開始以降に、レジスト膜を第2の温度条件下に保持する第2熱処理工程と、を含む。調製工程で調製する感放射線性樹脂組成物は、アルカリ可溶性樹脂(a)、活性放射線の照射、又は、活性放射線の照射及びその後の熱処理により、アルカリ可溶性樹脂を架橋する架橋成分(b)、及び活性放射線を吸収する化合物(c)を含有する。さらに、樹脂組成物は、架橋成分(b)が、活性放射線の照射によって酸を発生する化合物と、活性放射線によって発生した酸を触媒としてアルカリ可溶性樹脂を架橋する化合物との組み合わせであることを特徴とする。さらにまた、樹脂組成物は、活性放射線を吸収する化合物(c)を、アルカリ可溶性樹脂(a)100質量部に対して、1.0質量部超含む。
加えて、本発明のレジストパターン形成方法は、第2熱処理工程を経たレジスト膜を現像する現像工程を含みうる。
そして、本発明のレジストパターン形成方法は、第1の温度(いわゆる、プリベーク温度)が第2の温度(いわゆる、ポストベーク温度)以上であることを特徴とする。このように、樹脂組成物を用いてレジストパターンを形成するに当たり、露光工程前の第1熱処理工程における加熱温度を、露光工程開始以降の第2熱処理工程における第2の温度以上とすることで、逆テーパー形状が良好であり、更にかかる良好な逆テーパー形状を高温環境下でも維持することができるレジストパターンを形成することができる。その理由は明らかではないが、以下の通りであると推察される。
以下、本発明のレジストパターン形成方法に含まれる各工程について説明する。
調製工程では、アルカリ可溶性樹脂(a)、架橋成分(b)、及び活性放射線を吸収する化合物(c)を含み、任意で塩基性化合物(d)及びその他の成分をさらに含む感放射線性樹脂組成物を調製する。感放射線性樹脂組成物は、例えば、成分(a)~(d)を混合することによって得られる。得られた感放射線性樹脂組成物は、そのまま塗布工程に供されうる。或いは、溶剤に対して、上記成分(a)~(d)を添加して溶解させ、任意でろ過処理等を実施することで、感放射線性樹脂組成物溶液を調製することができる。成分(a)~(d)の混合、或いは(a)~(d)の溶剤への溶解に際して、ボールミル、サンドミル、ビーズミル、顔料分散機、らい潰機、超音波分散機、ホモジナイザー、プラネタリーミキサー、フィルミックスなどの既知の混合機を用いることができる。また、濾過に際して、フィルター等のろ材を用いた一般的なろ過方法を採用することができる。以下、感放射線性樹脂組成物に含有されうる各成分、及び感放射線性樹脂組成物溶液の調製に際して使用しうる溶剤について説明する。
本発明のレジストパターン形成方法で使用する感放射線性樹脂組成物(以下、単に「樹脂組成物とも称する」)は、アルカリ可溶性樹脂(a)、活性放射線の照射、又は、活性放射線の照射及びその後の熱処理により、アルカリ可溶性樹脂を架橋する架橋成分(b)、及び活性放射線を吸収する化合物(c)を含有する。さらに、樹脂組成物は、架橋成分(b)が、活性放射線の照射によって酸を発生する化合物と、活性放射線によって発生した酸を触媒としてアルカリ可溶性樹脂を架橋する化合物との組み合わせであることを特徴とする。さらにまた、樹脂組成物は、活性放射線を吸収する化合物(c)を、アルカリ可溶性樹脂(a)100質量部に対して、1.0質量部超含むことを特徴とする。樹脂組成物は、特に、化合物(c)を1.0質量部超含むことで、良好な逆テーパー形状のレジストパターンを形成するとともに、高温環境下でもかかる良好な逆テーパー形状を維持することができる。その理由は明らかではないが、以下の通りであると推察される。
なお、本明細書において、「側壁がレジスト表面に対してなす角度」は、逆テーパー構造を形成する側壁とレジスト表面とがなす、鋭角側の角度をいう。
アルカリ可溶性樹脂としては、特に限定されることなく、レジストの形成に一般的に用いられうるアルカリ可溶性樹脂を用いることができる。本明細書において「アルカリ可溶性樹脂」とは、当該成分を含むネガ型感光性樹脂組成物の現像処理工程において用いられる現像液、特に好ましくはアルカリ現像液に対して溶解性を有する樹脂である。なお、「アルカリ現像液に対して溶解性を有する」とは、アルカリ現像液と樹脂溶液とを混合した際に、目視で透明な混合溶液が得られることを意味する。より具体的には、本明細書において「アルカリ可溶性」とは、pH8以上の溶液に溶解したときに、不溶分率が0.1質量%未満である樹脂をいう。例えば、アルカリ可溶性樹脂としては、ノボラック樹脂、ポリビニルフェノール樹脂、ポリビニルアルコール樹脂、レゾール樹脂、アクリル樹脂、スチレン-アクリル酸共重合体樹脂、ヒドロキシスチレン重合体樹脂、及びポリビニルヒドロキシベンゾエート、並びにこれらの混合樹脂等が挙げられる。中でも、ノボラック樹脂を単独で、或いは他の樹脂と混合して用いることが好ましい。
ノボラック樹脂としては、市販のノボラック樹脂や、例えば、フェノール類とアルデヒド類またはケトン類とを酸性触媒(例えば、シュウ酸)の存在下で反応させることにより得たノボラック樹脂を使用することができる。
ポリビニルフェノール樹脂としては、例えば、ビニルフェノールの単独重合体、及びビニルフェノールとこれと共重合可能な単量体との共重合体などが挙げられる。ビニルフェノール樹脂と共重合可能な単量体としては、例えば、イソプロペニルフェノール、アクリル酸、メタクリル酸、スチレン、無水マレイン酸、マレイン酸イミド、酢酸ビニルが挙げられる。ポリビニルフェノール樹脂としては、ビニルフェノールの単独重合体が好ましく、p-ビニルフェノールの単独重合体がより好ましい。
ノボラック樹脂及びポリビニルフェノール樹脂の重量平均分子量は、合成条件を調整することにより、所望の範囲に制御することができる。例えば、ノボラック樹脂又はポリビニルフェノール樹脂の製造時に添加する反応原料の添加量を調節することにより各樹脂の重量平均分子量を調節することができる。より具体的には、縮合反応のために添加するホルムアルデヒド、ホルマリンまたはパラホルムアルデヒドの配合量を多くすることで、得られるノボラック樹脂の重量平均分子量を大きくすることができる。また、例えば、ポリビニルフェノール樹脂の重合時に添加する重合開始剤の量を少なくすることにより、得られるポリビニルフェノール樹脂の重量平均分子量を大きくすることができる。さらには、例えば、ノボラック樹脂又はポリビニルフェノール樹脂の合成時の反応時間を長くすることによっても、得られる各樹脂の重量平均分子量を大きくしうる。
この他、例えば、(1)合成により得られた樹脂や市販の樹脂を粉砕し、適当な溶解度を持つ有機溶剤で固-液抽出する方法、(2)合成により得られた樹脂や市販の樹脂を良溶剤に溶解させ、貧溶剤中に滴下するか、または貧溶剤を滴下して、固-液もしくは液-液抽出する方法などにより、重量平均分子量を制御することができる。
架橋成分は、活性放射線の照射、又は、活性放射線の照射及びその後の熱処理によってアルカリ可溶性樹脂(a)を架橋する成分である。この架橋成分の作用によりレジストの露光領域にて架橋構造が形成されることで、露光領域のアルカリ可溶性樹脂の分子量が大きくなって、アルカリ現像液に対する溶解速度が極端に低下する。それによって、樹脂組成物は、アルカリ現像液による現像が可能なネガ型レジスト材料として機能する。
活性放射線によって酸を発生する化合物である光酸発生剤としては、活性放射線を照射されると、ブレンステッド酸またはルイス酸を発生する物質であれば特に制限はなく、オニウム塩、ハロゲン化有機化合物、キノンジアジド化合物、スルホン化合物、有機酸エステル化合物、有機酸アミド化合物、有機酸イミド化合物など公知のものを用いることができる。これらの光酸発生剤は、パターンを露光する光源の波長に応じて、分光感度の面から選択することが好ましい。
酸架橋剤は、活性放射線の照射(露光)によって生じた酸の存在下で、アルカリ可溶性樹脂を架橋しうる化合物(感酸物質)である。このような酸架橋剤としては、例えば、アルコキシメチル化尿素樹脂、アルコキシメチル化メラミン樹脂、アルコキシメチル化ウロン樹脂、アルコキシメチル化グリコールウリル樹脂、アルコキシメチル化アミノ樹脂などの周知の酸架橋性化合物を挙げることができる。
なお、酸架橋剤は、重量平均分子量が300以上の樹脂であることが好ましい。
活性放射線を吸収する化合物(c)は、レジスト膜に対して照射された活性放射線を吸収する。これにより、逆テーパー形状のレジストパターンを形成することができる。さらに、レジストパターンの形状は、レジスト膜に対して照射された活性放射線が、レジスト膜を通過して基板や基板上に形成されたITO膜などにより反射されることによっても影響されうる。そこで、樹脂組成物に含有される化合物(c)が反射された活性放射線を吸収することによって、レジストパターンの形状を良好に制御することができる。特に架橋成分として光酸発生剤と酸架橋剤との組み合わせを用いた樹脂組成物は、架橋型の化学増幅レジストであって、光の照射により生成した酸がレジスト膜内で拡散し、光が当たらない領域にまで架橋反応を起こすため、活性放射線を吸収する化合物(c)を存在させることにより、レジストパターンの形状を良好に制御することができる。
なお、本明細書にて「活性放射線を吸収する」とは、波長13.5nm以上450nmの範囲の何れかの波長域において、少なくとも一つの極大吸収波長λmaxをもつことをいう。
樹脂組成物は、化合物(c)を、アルカリ可溶性樹脂(a)100質量部に対して、1質量部超含み、好ましくは1.2質量部以上含み、より好ましくは1.5質量部以上含み、さらに好ましくは1.8質量部以上含み、通常、10.0質量部以下、好ましくは8.0質量部以下、より好ましくは5.0質量部以下、さらにより好ましくは3.5質量部以下含む。樹脂組成物における化合物(c)の配合量がアルカリ可溶性樹脂(a)100質量部に対して、1質量部超であれば、かかる樹脂組成物を用いて形成したレジストにおいて良好な逆テーパー形状のレジストパターンを形成するとともに、高温環境下でもかかる良好な逆テーパー形状を維持することができる。さらに、化合物(c)の配合量を上記上限値以下とすることで、樹脂組成物を用いて形成したレジストの耐熱性を一層向上させることができる。さらに、一般に、レジスト膜厚が厚い場合には、活性放射線がレジスト膜を透過し難いので、化合物(c)の配合量が比較的少なくてもよく、薄い場合には、比較的多く用いることが好ましい。
好ましくは、樹脂組成物に対して、塩基性化合物を配合する。本明細書において、塩基性化合物とは、光酸発生剤に由来する酸を捕捉しうる化合物を意味する。塩基性化合物を配合すれば、樹脂組成物の保存安定性を向上させるとともに、第2熱処理工程における熱処理温度の温度許容範囲(PEB温度マージン)を拡大することができるからである。第2熱処理工程における熱処理温度の温度許容範囲が拡大することで、レジストパターンの製造ばらつきを抑制することができるため、本発明のレジストパターン形成方法の柔軟性を高めることができる。塩基性化合物(d)としては、無機塩基性化合物及び有機塩基性化合物が挙げられる。樹脂組成物を用いたレジストの形成にあたり、有機溶媒への溶解性が高いことから、有機塩基性化合物がより好ましい。樹脂組成物溶液を基板上に塗布して形成した塗膜の均一性を向上させることができるからである。有機塩基性化合物としては、例えば、含窒素塩基性化合物、有機ハロゲン化物、アルコキシド、フォスファゼン誘導体、及びVerkade塩基などが挙げられる。中でも、塩基性化合物としては、含窒素塩基性化合物を用いることが好ましい。樹脂組成物の保存安定性を向上させることができるからである。
さらに、塩基性化合物(d)としては、比較的沸点が高い塩基性化合物が好ましい。具体的には、塩基性化合物(d)は、沸点が60℃以上であることが好ましく、100℃以上であることがより好ましく、150℃以上であることがさらに好ましく、通常、500℃以下である。塩基性化合物(d)の沸点が高ければ、後述する第1熱処理工程や第2熱処理工程における揮発が少なくなり、得られたポスト露光ベーク工程済みのレジスト膜中における塩基性化合物(d)の残存量が、樹脂組成物中における塩基性化合物(d)の配合比率に近い量となる。これにより、樹脂組成物を調製時に設計した通りの塩基性化合物(d)による酸の中和効果を、実際のレジストにて発揮させて、架橋反応が過剰に進行することを抑制して、レジストパターンが太くなることを、設計通りに、効果的に抑制することができる。かかる効果に鑑みて、塩基性化合物の沸点は、第1熱処理工程における熱処理温度(以下、「プリベーク温度」とも称する)及び第2熱処理工程における熱処理温度(以下、「ポスト露光ベーク温度」とも称する)よりも10℃以上高いことが好ましく、30℃以上高いことがより好ましく、50℃以上高いことがさらに好ましい。
さらにまた、塩基性化合物は、重量平均分子量が300未満の化合物であることが好ましい。
樹脂組成物は、塩基性化合物(d)を、アルカリ可溶性樹脂(a)100質量部に対して、通常0.001~10質量部、好ましくは0.005~8質量部、より好ましくは0.01~5質量部含有することができる。塩基性化合物(d)の含有量が上記下限値以上であれば、樹脂組成物の保存安定性を向上させるとともにPEB温度マージンを拡大することができる。さらに、塩基性化合物(d)の含有量が上記上限値超えとなると、保存安定性の改善効果が飽和すると共に、レジスト特性に悪影響を及ぼす虞がある。
さらに、樹脂組成物における塩基性化合物(d)の配合量は、質量基準で、光酸発生剤の配合量の0.001倍以上が好ましく、0.050倍以上がより好ましく、0.200倍以上がさらに好ましく、3.500倍未満が好ましく、2.000倍未満がより好ましく、0.500倍未満がさらに好ましい。光酸発生剤に対して塩基性化合物(d)を上記下限値以上の比率で配合することで、PEB温度マージンの許容範囲を拡大することができる。また、塩基性化合物(d)の配合量を上記上限値以下とすることで、露光により生じた酸を過剰に中和して架橋反応の進行を阻害することを回避することができる。これにより、樹脂組成物を用いて形成したレジストパターンの逆テーパー形状を良好なものとすることができる。また、塩基性化合物(d)の配合量を上記上限値以下とすることで、樹脂組成物を用いて形成したレジストの感度を向上させることができる。
樹脂組成物に対して、任意で、界面活性剤を添加することができる。界面活性剤としては、例えば、ポリオキシエチレンラウリルエーテル、ポリオキシエチレンステアリルエーテル、ポリオキシエチレンオレイルエーテル等のポリオキシエチレンアルキルエーテル類;ポリオキシエチレンオクチルフェニルエーテル、ポリオキシエチレンノニルフェノルエーテルなどのポリオキシエチレンアリールエーテル類;ポリエチレングリコールジラウレート、エチレングリコールジステアレート等のポリエチレングリコールジアルキルエステル類;エフトップ EF301、EF303、EF352(新秋田化成社製)、メガファックス F171、F172、F173、F177(大日本インキ社製)、フロラードFC430、FC431(住友スリーエム社製)、アサヒガード AG710、サーフロン S-382、SC-101、SC-102、SC-103、SC-104、SC-105、SC-106(旭硝子社製)等のフッ素界面活性剤;オルガノシロキサンポリマー KP341(信越化学工業社製);アクリル酸系またはメタクリル酸系(共)重合体ポリフローNo.75、No.95(共栄社油脂化学工業社製)が挙げられる。これらの界面活性剤の配合量は、樹脂組成物の固形分100質量部当り、通常2質量部以下、好ましくは1質量部以下である。
上述した各成分を溶解させる溶剤としては、有機溶剤を用いることが好ましい。有機溶剤は、上述したような各成分を均一に溶解または分散し得るために十分な量で用いられる。樹脂組成物溶液中の固形分濃度は、通常5~50質量%、好ましくは10~40質量%程度である。
塗布工程では、調製工程で得られた樹脂組成物を基板上に塗布及び乾燥して塗膜を形成する。また、基板は、半導体基板として使用されうる一般的な基板であれば特に限定されることなく、例えば、シリコン基板、ガラス基板、ITO膜形成基板、クロム膜形成基板、樹脂基板でありうる。また、塗布方法としては、スピンコーティング、スプレー、ハケ塗り等により塗布する方法、ディップコーティング等の一般的な塗布方法を採用することができる。
第1熱処理工程では、塗布工程にて形成した塗膜を第1の温度で加熱する。ここで、第1の温度であるプリベーク温度は、第2の温度であるポストベーク温度よりも高いことが好ましく、5℃以上高いことがより好ましく、10℃以上高いことがさらに好ましい。プリベーク温度がポストベーク温度よりも高ければ、得られるレジストパターンの逆テーパー形状を一層良好なものとするとともに、かかる良好な逆テーパー形状を高温環境下でも一層良好に維持することができる。なお、第1の温度であるプリベーク温度は80℃以上が好ましく、100℃以上がより好ましく、105℃以上がさらに好ましく、130℃以下が好ましく、125℃以下がより好ましい。また、第1熱処理工程の時間は、10秒以上200秒以下でありうる。また、第1熱処理工程は、特に限定されることなく、一般的なベーク装置に備えられたホットプレート等の加熱機構上に塗膜を形成した基板を載置することにより、実施可能であり、プリベーク温度は、ホットプレートの設定温度を変更することにより、制御することができる。そして、第1熱処理工程を経て得られたレジスト膜の膜厚は、通常0.1μm以上15μm以下である。
露光工程では、第1熱処理工程を経て得られたレジスト膜に対して、活性放射線を照射する。活性放射線は、波長13.5nm以上450nm以下であり、具体的には、紫外線、遠紫外線、エキシマレーザー光、X線、電子線、極端紫外光(Extreme Ultra Violet)などが挙げられる。露光光源としては、活性放射線を照射することが可能な光源であれば特に限定されることなく、例えば、紫外線光源、半導体レーザー照射装置、メタルハライドランプ、高圧水銀灯、エキシマレーザー(KrF,ArF,F2)照射装置、X線露光装置、電子線露光装置、及びEUV露光装置等が挙げられる。
そして、露光量は、通常、10mJ/cm2以上、2000mJ/cm2以下であり、露光時間は、通常、1秒以上180秒以下である。
第2熱処理工程では、露光工程開始後のレジスト膜を第2の温度条件下に保持する。具体的には、第2熱処理工程は露光工程の開始後であれば、露光工程が完了する前に開始しても良いし、露光工程が完了した後に開始しても良い。第2熱処理工程は、第1熱処理工程と同様の装置により実施することができるが、露光工程が完了する前に第2熱処理工程を開始する場合には、露光装置の試料台がホットプレート様の機能を有することが好ましい。第2の温度は、第1の温度以下であり、好ましくは20℃以上、より好ましくは80℃以上、通常130℃以下、好ましくは120℃以下、より好ましくは115℃以下でありうる。また、第2熱処理工程の時間は、通常10秒以上、好ましくは、60秒以上、より好ましくは100秒以上であり、通常200秒以下である。第2熱処理工程にて、露光工程を経たレジスト膜を第2の温度条件下に保持することで、架橋成分(b)の架橋反応を促進することができる。なお、活性放射線の照射のみにより十分な架橋反応が生じるアルカリ可溶性樹脂(a)及び架橋成分(b)の組み合わせを採用した場合にあっては、第2熱処理工程では、レジスト膜を「加熱」せずに、室温程度(例えば、25℃)の雰囲気下にて所定時間保持しても良い。
アルカリ現像液を用いて、パドル現像、スプレー現像、及びディップ現像等の一般的な現像方法により、レジストパターンを現像する。現像工程にて使用するアルカリ現像液は、pH8以上のアルカリ水溶液でありうる。アルカリとしては、水酸化ナトリウム、水酸化カリウム、ケイ酸ナトリウム、アンモニアなどの無機アルカリ;エチルアミン、プロピルアミンなどの第一級アミン類;ジエチルアミン、ジプロピルアミンなどの第二級アミン類;トリメチルアミン、トリエチルアミンなどの第三級アミン類;ジエチルエタノールアミン、トリエタノールアミンなどのアルコールアミン類;テトラメチルアンモニウムヒドロキシド、テトラエチルアンモニウムヒドロキシド、トリエチルヒドロキシメチルアンモニウムヒドロキシド、トリメチルヒドロキシエチルアンモニウムヒドロキシドなどの第四級アンモニウムヒドロキシド類;などが挙げられる。また、必要に応じて、アルカリ水溶液には、メチルアルコール、エチルアルコール、プロピルアルコール、エチレングリコールなどの水溶性有機溶剤、界面活性剤、樹脂の溶解抑制剤などを添加することができる。
本発明のレジストは、アルカリ可溶性樹脂(a)、活性放射線の照射、又は、活性放射線の照射及びその後の熱処理により、アルカリ可溶性樹脂を架橋する架橋成分(b)、及び活性放射線を吸収する化合物(c)を含有する感放射線性樹脂組成物であって、(1)架橋成分(b)が、活性放射線の照射によって酸を発生する化合物と、活性放射線によって発生した酸を触媒としてアルカリ可溶性樹脂(a)を架橋する化合物との組み合わせであり、(2)活性放射線を吸収する化合物(c)を、アルカリ可溶性樹脂(a)100質量部に対して、1.0質量部超含む、感放射線性樹脂組成物を用いて形成され、ライン及びスペースからなる、断面が逆テーパー形状のレジストパターンを形成した場合に、非露光面におけるライン幅Wbに対する露光面におけるライン幅Wtの比率Wb/Wtが、0.7未満、好ましくは0.6未満であり、120℃の温度条件下で1分間加熱した後にレジストパターンの逆テーパー形状を構成するラインの側壁がレジスト表面に対してなす角度が、90°未満である。かかるレジストは、本発明のレジストパターン形成方法により得られ、テーパー角度が十分に大きく、さらに高温環境下においた場合であっても良好な逆テーパー形状を維持することができるレジストパターンを有する。そして、かかるレジストには、少なくとも、アルカリ可溶性樹脂(a)、架橋成分(b)、及び活性放射線を吸収する化合物(c)が含有されており、任意で、塩基性化合物(d)及びその他の成分が含有されている。なお、レジスト中に含まれている各成分は、上記感放射線性樹脂組成物に含有されていたものであり、それらの好適な存在比は、樹脂組成物中の各成分の好適な存在比と同じである。さらに、レジスト中では、アルカリ可溶性樹脂(a)が相互に架橋された状態で存在する。本発明のレジストは、配線パターンの形成に用いた場合に、微細な配線パターンを良好に形成することができる。また、本発明のレジストは、耐熱性に優れるため、レジストパターンを加熱してもテーパー形状を維持することでき、例えば、一般的に高温環境下で行われる金属蒸着による配線パターンの形成に用いた場合に、微細な配線パターンを良好に形成することができる。
実施例および比較例において、レジストの逆テーパー形状及び耐熱性は、それぞれ、以下のようにして測定及び評価した。また、実施例及び比較例に用いたアルカリ可溶性樹脂の重量平均分子量の測定条件は以下の通りとした。
実施例、比較例で形成した、ライン(現像工程後に溶解せずに残る部分)とスペース(現像工程にてレジスト膜が溶解し、空隙となった部分)からなるレジストパターンについて、レジスト膜下面(即ち、基板側)におけるライン幅(ボトム線幅)と、レジスト膜上面におけるライン幅(トップ線幅)とを走査型電子顕微鏡(SEM)観察下でそれぞれ測定した。得られたボトム線幅をトップ線幅で除して、以下の基準に従って評価した。ボトム線幅/トップ線幅の値が大きいほど、ライン(現像工程後に溶解せずに残る部分)の逆台形の上底及び下底の長さの差が大きく、レジストパターンのテーパー角度が大きいことを意味する。
A:ボトム線幅/トップ線幅の値が0.6未満
B:ボトム線幅/トップ線幅の値が0.6以上0.7未満
C:ボトム線幅/トップ線幅の値が0.7以上
<耐熱性>
実施例、比較例でレジストパターンを形成した基板を、更に、ホットプレート上で120℃ で1分間加熱した。その後、レジストパターンを形成した基板について、SEMを用いて断面形状を観察し、逆テーパー形状を構成するレジストの側壁がレジスト表面に対してなす角度を測定し、以下の基準に従って耐熱性を評価した。本評価方法によれば、現像工程後に更に加熱した後にテーパー角が十分に大きい良好な逆テーパー形状を維持することができたことを評価することができる。即ち、形成されたレジストパターンが、例えば、金属配線材料等の蒸着工程に供されて加熱された場合であっても、良好な逆テーパー形状を維持しうるか評価することができる。
A:側壁がレジスト表面に対してなす角度が70°以下
B:側壁がレジスト表面に対してなす角度が70°超80°以下
C:側壁がレジスト表面に対してなす角度が80°超90°以下
C:側壁がレジスト表面に対してなす角度が90°超
-条件-
装置 :HLC-8120GPC(東ソー製)
カラム:TSKgel G5000HXL、内径7.8mm×長さ30cm(東ソー製)の2連
温度 :40℃
溶媒 :テトラヒドロフラン(THF)
流速 :1.0ml/分
試料 :濃度0.05~0.1質量%の試料を0.05~0.2ml注入
-検量線-
分子量がそれぞれ、5.0×102、2.5×103、9.83×103、3.72×104、1.89×105、7.07×105、1.11×106である、7種の東ソー製単分散ポリスチレン標準試料を用いて作成した分子量校正曲線を使用した。
<感放射線性樹脂組成物溶液の調製(調製工程)>
m-クレゾール70部及びp-クレゾール30部を、ホルムアルデヒド19部と脱水縮合して得た重量平均分子量3000のノボラック樹脂をアルカリ可溶性樹脂(a)として用いた。
かかるアルカリ可溶性樹脂(a)100部と、架橋成分(b)としての、ハロゲン含有トリアジン系光酸発生剤(みどり化学製、商品名「TAZ110」)2部、メラミン系架橋剤(酸架橋剤:三井サイテック製、商品名「サイメル303」)8部と、活性放射線を吸収する化合物(c)としてのビスアジド化合物(東洋合成工業製、商品名「BAC-M」)2部とを、有機溶剤としてのプロピレングリコールモノメチルエーテルアセテート(PGMEA)176部中に溶解させた。得られた感放射線性樹脂組成物の分散液を、孔径0.1μmのポリテトラフルオロエチレン製メンブランフィルターで濾過して、固形分濃度が39質量%の感放射線性樹脂組成物溶液を調製した。
基材としてのシリコンウェハ上に、スピンコーターを用いて感放射線性樹脂組成物溶液を塗布及び乾燥させて塗膜を形成した(塗布工程)。次いで、第1の温度(プリベーク温度)110℃に設定したホットプレート上に、表面に塗膜を有するシリコンウェハを載置し、90秒間保持して第1熱処理(プリベーク)工程を実施した。得られたレジスト膜の膜厚は4μmであった。
このレジスト膜の上から、20μmのライン&スペース(L&S)パターンのマスクを用いて、パラレルライトマスクアライナー(キャノン製、商品名「PLA501F」、紫外線光源、照射波長365nm~436nm)で露光した。露光量は、ライン部分の幅とスペース部分の幅との比率が1:1となる露光量とした(露光工程)。露光工程後、第2の温度(ポストベーク温度)100℃に設定してホットプレート上にレジスト膜付きのシリコンウェハを載置し、100秒間保持して第2熱処理(ポストベーク)工程を実施した。第2熱処理工程後、2.38質量%のテトラメチルアンモニウムヒドロキシド(TMAH)水溶液で、70秒間パドル現像し、L&Sのレジストパターンを得た。レジストパターンの断面形状は、逆テーパー形状であった。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
感放射線性樹脂組成物溶液の調製にあたり塩基性化合物(d)として、トリエタノールアミン(TEOA)0.5部をさらに配合した以外は、実施例1と同様として、レジストパターンを形成した。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
感放射線性樹脂組成物溶液の調製にあたり、活性放射線を吸収する化合物(c)の配合量を表1に示す通りに変更した以外は実施例1と同様にして、レジストパターンを形成した。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
レジストパターンの形成にあたり、それぞれ、第1熱処理(プリベーク)工程における第1の温度及び第2熱処理(ポストベーク)工程における第2の温度の組み合わせをそれぞれ表1に示す通りに変更した以外は、実施例1と同様にして、レジストパターンを形成した。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
レジストパターンの形成にあたり、それぞれ、第1熱処理(プリベーク)工程における第1の温度よりも、第2熱処理(ポストベーク)工程における第2の温度を高く設定した以外は、実施例1と同様にして、レジストパターンを形成した。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
レジストパターンの形成にあたり、それぞれ、第1熱処理(プリベーク)工程における第1の温度と、第2熱処理(ポストベーク)工程における第2の温度とを同一温度に設定し、且つ、活性放射線を吸収する化合物(c)の配合量を1質量部に変更した以外は、実施例1と同様にして、レジストパターンを形成した。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
レジストパターンの形成にあたり、第1熱処理(プリベーク)工程における第1の温度を、第2熱処理(ポストベーク)工程における第2の温度よりも高く設定したが、活性放射線を吸収する化合物(c)の配合量は1質量部に変更した。この点以外は、実施例1と同様にして、レジストパターンを形成した。そして、得られたレジストパターンについて上述の方法に従って評価を行った結果を表1に示す。
また、本発明のレジストは、レジストパターンの逆テーパー形状が良好であり、耐熱性に優れる。
Claims (3)
- 感放射線性樹脂組成物を調製する調製工程と、
基板上に、前記感放射線性樹脂組成物を塗布及び乾燥して塗膜を形成する塗布工程と、
前記塗膜を第1の温度で加熱する第1熱処理工程と、
前記第1熱処理工程を経て得られたレジスト膜に対して、活性放射線を照射する露光工程と、
前記露光工程の開始以降に、前記レジスト膜を第2の温度条件下に保持する第2熱処理工程と、を含み、
前記感放射線性樹脂組成物が、アルカリ可溶性樹脂(a)、活性放射線の照射、又は、活性放射線の照射及びその後の熱処理により、前記アルカリ可溶性樹脂を架橋する架橋成分(b)、及び前記活性放射線を吸収する化合物(c)を含有する感放射線性樹脂組成物であって、(1)前記架橋成分(b)が、前記活性放射線の照射によって酸を発生する化合物と、前記活性放射線によって発生した酸を触媒として前記アルカリ可溶性樹脂(a)を架橋する化合物との組み合わせであり、(2)前記活性放射線を吸収する化合物(c)を、前記アルカリ可溶性樹脂(a)100質量部に対して、1.0質量部超含み、且つ、
前記第1の温度が前記第2の温度以上である、レジストパターン形成方法。 - 前記感放射線性樹脂組成物が、塩基性化合物(d)をさらに含む、請求項1に記載のレジストパターン形成方法。
- アルカリ可溶性樹脂(a)、活性放射線の照射、又は、活性放射線の照射及びその後の熱処理により、前記アルカリ可溶性樹脂を架橋する架橋成分(b)、及び前記活性放射線を吸収する化合物(c)を含有する感放射線性樹脂組成物であって、(1)前記架橋成分(b)が、前記活性放射線の照射によって酸を発生する化合物と、前記活性放射線によって発生した酸を触媒として前記アルカリ可溶性樹脂(a)を架橋する化合物との組み合わせであり、(2)前記活性放射線を吸収する化合物(c)を、前記アルカリ可溶性樹脂(a)100質量部に対して、1.0質量部超含む、感放射線性樹脂組成物を用いて形成され、
ライン及びスペースからなる、断面が逆テーパー形状のレジストパターンを形成した場合に、非露光面におけるライン幅Wbに対する露光面におけるライン幅Wtの比率Wb/Wtが、0.7未満であり、
120℃の温度条件下で1分間加熱した後に前記レジストパターンの逆テーパー形状を構成する前記ラインの側壁がレジスト表面に対してなす角度が、90°未満である、レジスト。
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| CN105404418B (zh) * | 2015-11-03 | 2018-09-04 | 京东方科技集团股份有限公司 | 触控屏及其制备方法、显示面板和显示装置 |
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- 2017-03-15 CN CN201780010236.5A patent/CN108700835B/zh active Active
- 2017-03-15 JP JP2018508999A patent/JP7044058B2/ja active Active
- 2017-03-15 WO PCT/JP2017/010518 patent/WO2017169807A1/ja not_active Ceased
- 2017-03-15 KR KR1020187023664A patent/KR102417026B1/ko active Active
- 2017-03-21 TW TW106109290A patent/TWI781094B/zh active
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| JPH02106919A (ja) * | 1988-10-17 | 1990-04-19 | Toshiba Corp | 逆テーパ形状のフォトレジストパターンの形成方法 |
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| WO2019129613A1 (en) * | 2017-12-28 | 2019-07-04 | Merck Patent Gmbh | A negative tone lift off resist composition comprising an alkali soluble resin and cross linkers and a method for manufacturing metal film patterns on a substrate |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108700835A (zh) | 2018-10-23 |
| KR20180132042A (ko) | 2018-12-11 |
| CN108700835B (zh) | 2022-05-27 |
| TW201800877A (zh) | 2018-01-01 |
| KR102417026B1 (ko) | 2022-07-05 |
| TWI781094B (zh) | 2022-10-21 |
| JPWO2017169807A1 (ja) | 2019-02-14 |
| JP7044058B2 (ja) | 2022-03-30 |
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