JPWO2017169807A1 - Resist pattern forming method and resist - Google Patents

Abstract

The resist pattern forming method of the present invention is a radiation-sensitive resin composition containing an alkali-soluble resin (a), a crosslinking component (b), and a compound (c) that absorbs actinic radiation, the resin (a) 100 A preparation step of preparing a radiation-sensitive resin composition containing more than 1.0 part by weight of compound (c) with respect to parts by weight, and a coating step of forming a coating film of the radiation-sensitive resin composition on a substrate A first heat treatment step for heating the coating film at a first temperature, an exposure step for irradiating the obtained resist film with actinic radiation, and after the exposure step starts, the resist film is subjected to a second temperature condition. And a second heat treatment step held at Here, the first temperature is equal to or higher than the second temperature.

Description

  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. .

  In the photolithography technique, a resist material that can form a resist pattern having a reverse taper in cross section may be required. Specifically, there are a case where 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. For example, when a wiring is formed by a lift-off method using a resist pattern having a reverse taper cross section, 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. If 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.

  Therefore, conventionally, there has been proposed a photoresist composition having a good reverse taper shape and capable of forming a highly sensitive resist pattern (see, for example, Patent Document 1). 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. In particular, 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 As a result, a resist pattern having a good reverse taper shape could be formed.

  Here, 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 (see, for example, Patent Document 2). The radiation sensitive resin composition by patent document 2 contains the specific alkali-soluble resin, the crosslinking component which bridge | crosslinks alkali-soluble resin, and the compound which absorbs actinic radiation. In particular, 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

In recent years, it is necessary to further miniaturize the wiring pattern of a semiconductor device. In miniaturization of the wiring pattern, 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.
However, in 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.

  Therefore, 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. For the purpose. 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.

That is, 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 In contrast, 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. In the first heat treatment step before the exposure step, 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. A reverse taper shape can be maintained.
Here, in this specification, the “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.

  Furthermore, in the resist pattern forming method of the present invention, it is preferable that the radiation-sensitive resin composition further includes 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.

  Moreover, this invention aims at solving the said subject advantageously, 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 by 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 temperature of 120 ° C. The angle formed by the side wall of the line constituting the reverse tapered shape of the resist pattern after heating for 1 minute under the conditions is less than 90 °. Such a resist has a good taper shape and excellent heat resistance.

According to 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.

  Hereinafter, embodiments of the present invention will be described in detail. 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. In particular, 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.

(Resist pattern formation method)
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. 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. And Furthermore, 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).
In addition, 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). Thus, in forming the resist pattern using the resin composition, 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.

Conventionally, 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. Here, in the radiation sensitive resin composition prepared in the preparation step, in particular, 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. Therefore, in the present invention, 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.
Hereinafter, each process included in the resist pattern forming method of the present invention will be described.

<Preparation process>
In the preparation step, 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. Prepare the product. 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. Alternatively, the radiation-sensitive resin composition solution can be prepared by adding the components (a) to (d) to the solvent and dissolving them, and optionally performing a filtration treatment or the like. When mixing components (a) to (d) or dissolving (a) to (d) in a solvent, a ball mill, a sand mill, a bead mill, a pigment disperser, a grinder, an ultrasonic disperser, a homogenizer, a planetary mixer A known mixer such as a fill mix can be used. Moreover, the general filtration method using filter media, such as a filter, can be employ | adopted at the time of filtration. Hereinafter, each component that can be contained in the radiation-sensitive resin composition and a solvent that can be used in preparing the radiation-sensitive resin composition solution will be described.

[Radiation sensitive resin composition]
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. And Furthermore, 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). In particular, 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.

  First, 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. Here, 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. For this reason, if there is a gradient in the dose of actinic radiation that reaches in the thickness direction of the resist film, more crosslinks are formed in the vicinity of the exposure surface where the dose is high, and the crosslinks that are formed as the distance from the exposure surface increases. Decrease. For this reason, the resist film in the vicinity of the exposed surface is difficult to be removed in the development process, and on the contrary, the solubility of the resist film in the developer increases as the surface approaches the surface opposite to the exposed surface. In this manner, a resist having a reverse tapered resist pattern can be formed.

And in this invention, 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. Increasing the difference between the amount of crosslink formation near the exposed surface and the amount of crosslink formation on the surface opposite to the exposed surface by including the compound (c) in such a high content ratio in the resin composition. It is inferred that In other words, it is possible to form an excellent reverse taper shape by sharpening the angle formed by the side walls constituting the reverse taper shape of the resist pattern with respect to the resist surface. If 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.

[[Alkali-soluble resin (a)]]
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. In the present specification, 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. More specifically, in the present specification, “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. For example, examples of 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.

-Novolac resin-
As the 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.

  Examples of phenols 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- Meto Shi-5-methylphenol, 2-t-butyl-5-methylphenol, thymol, and the like Isochimoru. These can be used alone or in combination of two or more.

  Examples of aldehydes include formaldehyde, formalin, paraformaldehyde, trioxane, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-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. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, and diphenyl ketone. These can be used alone or in combination of two or more.

  Among the above-mentioned, it is preferable to prepare a novolak resin by using metacresol and paracresol together and subjecting these to formaldehyde, formalin or paraformaldehyde to condensation reaction. This is because the molecular weight distribution of the polymer constituting the novolak resin can be easily controlled, so that the sensitivity of the resist can be easily controlled. The charging ratio of metacresol and paracresol is usually 80:20 to 20:80, preferably 70:30 to 40:60 on a mass basis.

  The average molecular weight of the novolak resin is a weight average molecular weight in terms of monodisperse polystyrene measured by 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. When the weight average molecular weight of the novolak resin is less than the above lower limit value, the effect of increasing the molecular weight is small even when a crosslinking reaction occurs in the exposed area, and the novolak resin is easily dissolved in the developer. When the weight average molecular weight of the novolak resin exceeds the above upper limit, the difference in solubility in the alkaline developer between the exposed and unexposed areas in the resist becomes small, making it difficult to obtain a good resist pattern.

-Polyvinylphenol resin-
Examples of the polyvinyl phenol resin include a homopolymer of vinyl phenol and a copolymer of vinyl phenol and a monomer copolymerizable therewith. Examples of the monomer copolymerizable with the vinylphenol resin include isopropenylphenol, acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, and vinyl acetate. As a polyvinyl phenol resin, the homopolymer of vinylphenol is preferable and the 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.

-Method for adjusting the weight average molecular weight of each resin-
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. For example, 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. For example, 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. Furthermore, for example, 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.
In addition, for example, (1) 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 a poor solvent can be dropped into a solid-liquid or liquid-liquid extraction to control the weight average molecular weight.

[[Crosslinking component (b)]]
A crosslinking component is a component which bridge | crosslinks alkali-soluble resin (a) by irradiation of actinic radiation, or irradiation of actinic radiation, and subsequent heat processing. By forming a crosslinked structure in the exposed region of the resist by the action of the crosslinking component, the molecular weight of the alkali-soluble resin in the exposed region is increased, and the dissolution rate in the alkaline developer is extremely reduced. Thereby, the resin composition functions as a negative resist material that can be developed with an alkaline developer.

  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.

[[[Photoacid generator]]]
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.

  Examples of 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. Halogen-containing oxazole compounds, halogen-containing triazole compounds, halogen-containing 2-pyrone compounds, other halogen-containing heterocyclic compounds, halogen-containing aliphatic hydrocarbon compounds, halogen-containing aromatic hydrocarbon compounds, sulfenyl halide compounds, etc. Is mentioned.

  Specific examples of the halogenated organic compound 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 (chloroethyl) ether of tetrachlorobisphenol A, tetrabromo Bisf Bis (bromoethyl) ether of diol A, bis (2,3-dichloropropyl) ether of bisphenol A, bis (2,3-dibromopropyl) ether of bisphenol A, bis (2,3-dichloropropyl) of tetrachlorobisphenol A ) Ether, bis (2,3-dibromopropyl) ether of tetrabromobisphenol A, tetrachlorobisphenol S, tetrabromobisphenol S, bis (chloroethyl) ether of tetrachlorobisphenol S, bis (bromoethyl) ether of tetrabromobisphenol S Bis (2,3-dichloropropyl) ether of bisphenol S, bis (2,3-dibromopropyl) ether of bisphenol S, tris (2,3-dibromopropyl) isocyanurate, 2,2- And halogen-based flame retardants such as bis (4-hydroxy-3,5-dibromophenyl) propane and 2,2-bis (4- (2-hydroxyethoxy) -3,5-dibromophenyl) propane; .

  Specific examples of the quinonediazide compound 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-diazide-5-sulfonic acid chloride, etc. Sulfonic acid chloride quinonediazide derivative; and the like.

  Specific examples of the sulfone compounds include sulfone compounds and disulfone compounds having unsubstituted, symmetrically or asymmetrically substituted alkyl groups, alkenyl groups, aralkyl groups, aromatic groups, or heterocyclic groups.

  Examples of 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.

  In addition, 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.

  A photo-acid generator is 0.1-10 mass parts normally with respect to 100 mass parts of alkali-soluble resin (a), Preferably it is 0.3-8 mass parts, More preferably, it is a ratio of 0.5-5 mass parts. Used in. If the ratio of the photoacid generator is too small or too large, the shape of the resist pattern may be deteriorated.

[[[Acid crosslinking agent]]]
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. Examples of such 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.

In addition, as an acid crosslinking agent, alkyl etherified melamine resin, benzoguanamine resin, alkyl etherified benzoguanamine resin, urea resin, alkyl etherified urea resin, urethane-formaldehyde resin, resol type phenol formaldehyde resin, alkyl etherified resole type phenol formaldehyde 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.

  Among these, 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. Among these, a methoxymethylated melamine resin such as hexamethoxymethylmelamine is particularly preferable in terms of good resolution. Commercially available products of alkoxymethylated melamine resins include, for example, PL-1170, PL-1174, UFR65, CYMEL (registered trademark) 300, CYMEL (registered trademark) 303 (manufactured by Mitsui Cytec), BX-4000, Nicarak Examples thereof include MW-30 and MX290 (manufactured by Sanwa Chemical Co., Ltd.).

  These acid crosslinking agents can be used alone or in combination of two or more. 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.

[[Compound that absorbs actinic radiation (c)]]
The compound (c) that absorbs actinic radiation absorbs actinic radiation irradiated to the resist film. Thereby, a reverse taper-shaped resist pattern can be formed. Furthermore, 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. In particular, 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.
In the present specification, “absorbing actinic radiation” means having at least one maximum absorption wavelength λmax in any wavelength range of 13.5 nm to 450 nm.

  Examples of the compound (c) that absorbs active 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. These can be used singly or in combination. Among them, as 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.

  Examples of the bisazide compound 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.

-Content of compound (c) that absorbs actinic radiation-
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. While forming a resist pattern, it is possible to maintain such a good reverse tapered shape even under a high temperature environment. Furthermore, 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.

[[Basic compounds]]
Preferably, a basic compound is blended with the resin composition. In the present specification, 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. Examples of the basic compound (d) include inorganic basic compounds and organic basic compounds. In forming a resist using the resin composition, 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. Examples of 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.

  Examples of 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. Preferably, an aliphatic primary amine, an aliphatic secondary amine, and an aliphatic tertiary amine are blended as the nitrogen-containing basic compound. Specific examples of the nitrogen-containing basic compound 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. Of these, triethanolamine is preferable.

-Properties of basic compound (d)-
Furthermore, the basic compound (d) is preferably a basic compound having a relatively high boiling point. Specifically, 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. As a result, the neutralization effect of the acid by the basic compound (d) as designed at the time of preparing the resin composition is exhibited in the actual resist, and it is possible to prevent the crosslinking reaction from proceeding excessively. A thick pattern can be effectively suppressed as designed. In view of such effects, 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.

-Blending amount of basic compound (d) (based on 100 parts by mass of alkali-soluble resin (a))-
A resin composition is 0.001-10 mass parts normally with respect to 100 mass parts of alkali-soluble resin (a), Preferably 0.005-8 mass parts, More preferably, a basic compound (d) is 0.00. It can contain 01-5 mass parts. 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.

-Blending amount of basic compound (d) (based on photoacid generator)-
Furthermore, 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. By adding the basic compound (d) to the photoacid generator at a ratio equal to or higher than the above lower limit, the allowable range of the PEB temperature margin can be expanded. Moreover, by making 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.

[[Other additives]]
A surfactant can be optionally added to the resin composition. Examples of 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; polyethylene glycol dialkyl esters such as polyethylene glycol dilaurate and ethylene glycol distearate; EFTOP EF301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafax F171, F172, F173, F177 (Dainippon) Ink), Florard FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S-382, S Fluorine surfactants such as C-101, SC-102, SC-103, SC-104, SC-105, SC-106 (Asahi Glass Co., Ltd.); organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.); acrylic acid type Or methacrylic acid (co) polymer polyflow No. 75, no. 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.). 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 5 to 50% by mass, preferably about 10 to 40% by mass.

  Examples of the organic solvent 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 cellosolve; ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate Cellosolve acetates such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and other alcohol ethers; propylene glycol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl acetate, propylene glycol Propylene glycols such as monobutyl ether; diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether and diethylene glycol diethyl ether; lactones such as γ-butyrolactone; halogenated hydrocarbons such as trichloroethylene; toluene, Aromatic hydrocarbons such as xylene; polar organic solvents such as dimethylacetamide, dimethylformamide, N-methylacetamide; mixed solvents of two or more of these.

<Application process>
In the coating step, 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. In addition, as a coating method, a general coating method such as spin coating, spraying, brush coating, or dip coating can be employed.

<First heat treatment step>
In the first heat treatment step, the coating film formed in the coating step is heated at a first temperature. Here, 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. or lower, and more preferably 125 ° C. or lower. The time for the first heat treatment step may be 10 seconds or more and 200 seconds or less. Further, 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.

<Exposure process>
In the exposure step, 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. 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, and the exposure time is usually 1 second or more and 180 seconds or less.

<Second heat treatment step>
In the second heat treatment step, the resist film after the start of the exposure step is held under the second temperature condition. Specifically, as long as the second heat treatment step is after the start of the exposure step, it may be started before the exposure step is completed, or may be started after the exposure step is completed. The second heat treatment step can be performed by the same apparatus as the first heat treatment step. However, when the second heat treatment step is started before the exposure step is completed, 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. or lower, more preferably 115 ° C. or lower. 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. In the second heat treatment step, 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. When a combination of an alkali-soluble resin (a) and a crosslinking component (b) that cause a sufficient crosslinking reaction only by irradiation with actinic radiation is employed, 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 (eg, 25 ° C.).

<Development process>
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. Examples of the alkali 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. If necessary, 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.

  When the resist pattern obtained through the development process is used in the lift-off method, 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. When producing 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.

(Resist)
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). When a resist pattern formed of a resin composition and made of lines and spaces and having a cross-section with a reverse taper is formed, 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. Such 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. In addition, since the resist of the present invention is excellent in heat resistance, it can maintain a tapered shape even when the resist pattern is heated. For example, 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.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the following description, “%” and “part” representing amounts are based on mass unless otherwise specified.
In the examples and comparative examples, the reverse taper shape and heat resistance of the resist were measured and evaluated as follows. Moreover, the measurement conditions of the weight average molecular weight of alkali-soluble resin used for the Example and the comparative example were as follows.

<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 larger the bottom line width / top line width value, the greater the difference in length between the upper and lower bases of the inverted trapezoid of the line (the portion that remains undissolved after the development process), and the greater the taper angle of the resist pattern. Means.
A: Bottom line width / top line width value of less than 0.6 B: Bottom line width / top line width value of 0.6 or more and less than 0.7 C: Bottom line width / top line width value of 0. 7 or more <Heat resistance>
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. Thereafter, 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. . According to 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.
A: Angle formed by the side wall with respect to the resist surface is 70 ° or less B: Angle formed by the side wall with respect to the resist surface is more than 70 ° and less than 80 ° C: Angle formed by the side wall with respect to the resist surface is more than 80 ° and 90 ° C: Angle formed by the side wall with respect to the resist surface exceeds 90 °

<Measurement of weight average molecular weight>
-conditions-
Apparatus: HLC-8120GPC (manufactured by Tosoh)
Column: TSKgel G5000HXL, inner diameter 7.8 mm × length 30 cm (manufactured by Tosoh Corp.) Temperature: 40 ° C.
Solvent: Tetrahydrofuran (THF)
Flow rate: 1.0 ml / min Sample: 0.05-0.2 ml of a sample having a concentration of 0.05-0.1% by mass is injected.
-Calibration curve-
The molecular weights are 5.0 × 10 ² , 2.5 × 10 ³ , 9.83 × 10 ³ , 3.72 × 10 ⁴ , 1.89 × 10 ⁵ , 7.07 × 10 ⁵ , 1.11 ×, respectively. A molecular weight calibration curve prepared using 7 types of Tosoh monodisperse polystyrene standard samples, 10 ⁶ , was used.

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).
100 parts of the alkali-soluble resin (a), 2 parts of a halogen-containing triazine photoacid generator (manufactured by Midori Chemical, trade name “TAZ110”) as a crosslinking component (b), a melamine-based crosslinking agent (acid crosslinking agent: 8 parts of Mitsui Cytec, trade name “Cymel 303”) and 2 parts of a bisazide compound (trade name “BAC-M”, manufactured by Toyo Gosei Co., Ltd.) as the compound (c) that absorbs active radiation, as an organic solvent In 176 parts of propylene glycol monomethyl ether acetate (PGMEA). The obtained dispersion of the radiation sensitive resin composition was filtered through a polytetrafluoroethylene membrane filter having a pore size of 0.1 μm to prepare a radiation sensitive resin composition solution having a solid content concentration of 39% by mass.

<Formation of resist pattern>
On the silicon wafer as a base material, the radiation sensitive resin composition solution was apply | coated and dried using the spin coater, and the coating film was formed (application | coating process). Next, 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 μm.
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 μm 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). After the exposure process, the second temperature (post-bake temperature) was set to 100 ° C., 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. . After the second heat treatment step, paddle development was performed for 70 seconds with a 2.38 mass% aqueous tetramethylammonium hydroxide (TMAH) solution to obtain an L & S resist pattern. The cross-sectional shape of the resist pattern was a reverse taper shape. Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.

(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.

(Examples 3 to 4)
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.

(Examples 5 to 9)
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.

(Comparative Examples 1-3)
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.

(Comparative 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.

(Comparative Example 5)
In forming the resist pattern, the first temperature in the first heat treatment (pre-baking) step was set higher than the second temperature in the second heat treatment (post-baking) step, but the compound (c) that absorbs active radiation is used. The blending amount was changed to 1 part by mass. Except for this point, a resist pattern was formed in the same manner as in Example 1. Table 1 shows the results of evaluating the obtained resist pattern according to the above-described method.

  From Table 1, it is a radiation-sensitive resin composition containing an alkali-soluble resin (a), a photoacid generator and an acid crosslinking agent as a crosslinking component (b), and a compound (c) that absorbs active radiation. In Examples 1 to 9, in which the pre-baking temperature is equal to or higher than the post-baking temperature, using a resin composition containing more than 1.0 part by weight of the compound (c) with respect to 100 parts by weight of the alkali-soluble resin (a) 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. On the other hand, in Comparative Examples 1 to 3 in which the pre-baking temperature is lower than the post-baking temperature and Comparative Examples 4 to 5 in which the content of the compound (c) is 1 part by mass or less, both a good taper shape and heat resistance are achieved. I can't understand.

According to the present invention, it is possible to form a resist pattern having a good reverse taper shape and further excellent heat resistance.
In addition, the resist of the present invention has a good reverse taper shape of the resist pattern and is excellent in heat resistance.

Claims (3)

A preparation step of preparing a radiation-sensitive resin composition;
On the substrate, an application step of applying and drying the radiation sensitive resin composition to form a coating film,
A first heat treatment step of heating the coating film at a first temperature;
An exposure step of irradiating actinic radiation to the resist film obtained through the first heat treatment step;
A second heat treatment step of holding the resist film under a second temperature condition after the start of the exposure step,
The radiation-sensitive resin composition comprises an alkali-soluble resin (a), actinic radiation, or a crosslinking component (b) that crosslinks the alkali-soluble resin by irradiation with actinic radiation and subsequent heat treatment, and the actinic radiation. A radiation-sensitive resin composition containing a compound (c) that absorbs the radiation, wherein (1) the crosslinking component (b) is generated by the active radiation and the compound that generates an acid upon irradiation with the active radiation It is a combination with a compound that crosslinks the alkali-soluble resin (a) using an acid as a catalyst, and (2) the compound (c) that absorbs active radiation is added to 100 parts by mass of the alkali-soluble resin (a). More than 1.0 parts by weight, and
A resist pattern forming method, wherein the first temperature is equal to or higher than the second temperature.   The resist pattern formation method of Claim 1 with which the said radiation sensitive resin composition further contains a basic compound (d). Contains alkali-soluble resin (a), actinic radiation, or a crosslinking component (b) that crosslinks alkali-soluble resin by irradiation with actinic radiation and subsequent heat treatment, and compound (c) that absorbs actinic radiation (1) The alkali-soluble resin (1) wherein the crosslinking component (b) is a compound that generates an acid upon irradiation with the active radiation and an acid generated by the active radiation as a catalyst. a combination with a compound that crosslinks a), and (2) a compound (c) that absorbs active radiation contains more than 1.0 part by mass with respect to 100 parts by mass of the alkali-soluble resin (a). Formed using a radiation resin composition,
When a resist pattern having a cross section with a reverse taper shape formed of lines and spaces is formed, 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,
A resist in which an angle formed by a side wall of the line constituting an inversely tapered shape of the resist pattern with respect to a resist surface after heating for 1 minute under a temperature condition of 120 ° C. is less than 90 °.