Photosensitive composition and pattern formation method

Abstract

To provide a high sensitivity and high resolution photosensitive composition corresponding to the miniaturization requirements of circuit patterns, and a pattern formation method using the photosensitive composition.SOLUTION: A photosensitive composition contains a tri-substituted organic tin compound with pyridine dicarboxylic acid as a ligand. A pattern formation method includes a process of forming a photosensitive layer on a substrate using this photosensitive composition, a process of exposing a specific area of the photosensitive layer to chemical radiation for pattern exposure, and a process of developing the exposed photosensitive layer with a developer to selectively remove the exposed or unexposed portions of the photosensitive layer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photosensitive composition suitable for use in ultra-microlithography processes such as the manufacture of ultra-LSIs and high-capacity microchips, and other photofabrication processes, and a pattern forming method using the photosensitive composition. More specifically, the present invention relates to a photosensitive composition suitable for use in the microfabrication of semiconductor elements using electron beams, X-rays, and EUV light (wavelength: about 13 nm), and a pattern forming method using the photosensitive composition. [Background technology]

[0002] Conventionally, in the manufacturing process of semiconductor devices such as ICs and LSIs, microfabrication is carried out by lithography using a photoresist composition. In recent years, with the increasing integration of integrated circuits, there has been a demand for ultrafine pattern formation in the submicron region or quarter-micron region. Accordingly, there is a trend toward shorter wavelengths of exposure light, from g-line to i-line, and further to KrF excimer laser light. Furthermore, at present, in addition to excimer laser light, lithography using electron beams, X-rays, or EUV light is also being developed.

[0003] Electron beam, X-ray, or EUV photolithography is positioned as the next-generation or next-next-generation pattern formation technology, and resists with high sensitivity and high resolution are desired. In particular, increasing sensitivity is a very important issue in order to shorten wafer processing times. However, the pursuit of higher sensitivity not only results in a decrease in resolution, but also in deterioration of line width roughness, and there is a strong demand for the development of a resist that satisfies both of these characteristics. Here, line width roughness refers to the phenomenon in which the edge of the resist pattern and the substrate interface fluctuates irregularly in the direction perpendicular to the line direction due to the characteristics of the resist, so that the edge appears uneven when the pattern is viewed from directly above. This unevenness is transferred during the etching process using the resist as a mask, degrading the electrical characteristics and reducing the yield.

[0004] There is a trade-off between high sensitivity, high resolution, good pattern shape, and good line width roughness, and it is very important to find a way to simultaneously satisfy all of these requirements. There are two types of resist compositions: "positive-type" resist compositions, which use a resin that is poorly soluble or insoluble in a developer and form a pattern by making the exposed area soluble in the developer through exposure to radiation, and "negative-type" resist compositions, which use a resin that is soluble in a developer and form a pattern by making the exposed area poorly soluble or insoluble in the developer through exposure to radiation.

[0005] As resists suitable for lithography processes using such electron beams, X-rays, or EUV light, chemically amplified positive resists that mainly utilize acid catalysis have been considered from the viewpoint of increasing sensitivity.

[0006] On the other hand, in the manufacture of semiconductor devices, etc., there is a demand for the formation of various patterns such as lines, trenches, holes, etc. In order to meet the demands for the formation of various patterns, not only positive resist compositions but also negative resist compositions have been developed. For example, Patent Documents 1 and 2 disclose a negative chemically amplified resist composition for electron beams or X-rays, and a pattern formation method in which a film formed by the composition is exposed to light and then developed with an alkaline developer.

[0007] In the formation of ultrafine patterns, there is a demand for further improvements in terms of resolution and line width roughness. Also known are pattern formation methods that utilize the direct cleavage of a resin main chain by exposure to light. For example, Patent Documents 3 and 4 disclose non-chemically amplified positive resist compositions containing PMMA (polymethyl methacrylate) or a copolymer of α-methyl α-chloroacrylate and α-methylstyrene, in which polymer chains are cleaved by exposure to radiation such as an electron beam, the molecular weight is reduced, and the dissolution rate in an organic solvent as a developer increases, forming a pattern. However, in the ultrafine region, high sensitivity, high resolution, good pattern shape, and good line width roughness cannot be simultaneously satisfied at the present time.

[0008] In semiconductor photolithography technology, according to Moore's Law, circuit patterns become smaller as semiconductor devices become finer, and further miniaturization is desired. Photolithography is roughly divided into the shortening of the wavelength of the light source of the exposure device and the photoresist that reacts to it. Photoresists are required to satisfy all of high resolution, low roughness, and high sensitivity, and it is thought that conventional resists containing photoacid generators, called chemically amplified types, cannot accommodate ultra-fine patterns because the diffusion of acid leads to a decrease in resolution. In recent years, non-chemically amplified photoresists mainly composed of compounds containing metal elements such as Zn and Sn have been proposed, and it has been reported that fine patterns can be formed with next-generation exposure devices using EUV (extreme ultraviolet) light (Patent Documents 5 to 7). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2002-148806 A [Patent Document 2] JP 2008-268935 A [Patent Document 3] Japanese Patent Application Publication No. 62-175739 [Patent Document 4] JP 2006-227174 A [Patent Document 5] Special Publication No. 2021-503482 [Patent Document 6] Patent No. 6805244 [Patent Document 7] Patent No. 6902849 Summary of the Invention [Problem to be solved by the invention]

[0010] In photolithography, particularly in semiconductor photolithography, there is a demand for photosensitive compositions and pattern forming methods that are excellent in resolution as resists and can realize finer circuit patterns.

[0011] The present invention has been made in view of the above-mentioned conventional techniques, and has an object to provide a photosensitive composition having high sensitivity and high resolution in response to the demand for finer circuit patterns, and a pattern forming method using the photosensitive composition. [Means for solving the problem]

[0012] As a result of extensive research, the present inventors have found that a photoresist containing a specific metal-containing low molecular weight compound that forms a Metal-Organic Flamework functions well as a photoresist suitable for ultrafine patterns, and have completed the present invention. That is, the present invention relates to the following.

[0013] [1] A photosensitive composition comprising a tri-substituted organotin compound having a pyridinedicarboxylic acid as a ligand.

[0014] [2] The tri-substituted organotin compound is SnR 1 R 2 R 3 It is expressed as R 1 ~R 3 each independently represents a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

[0015] [3] The photosensitive composition according to [1] or [2], wherein the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is a compound represented by the following formula (1):

[0016] [ka]

[0017] (In formula (1), R 1 ~R 3 are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, each of which may have a substituent; G is not present, or if present, G is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms; M is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, an aromatic group having 3 to 10 carbon atoms, or a substituent represented by the following formula (2), and n is an integer of 1 or more.

[0018] [ka]

[0019] (In formula (2), R 4 ~R 6 are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

[0020] [4] R 1 ~R 3 The photosensitive composition according to [2] or [3], wherein the hydrocarbon bonded to Sn is methylene.

[0021] [5] The photosensitive composition according to [3] or [4], wherein n in the formula (1) is 1 to 10.

[0022] [6] R 1 ~R 3 each independently represents a linear saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms.

[0023] [7] The photosensitive composition according to any one of [1] to [6], further comprising a photoacid generator that generates an acid by the action of actinic radiation.

[0024] [8] The photosensitive composition according to any one of [1] to [7], wherein the molecular weight of the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is 300 to 8,000.

[0025] [9] The photosensitive composition according to any one of [1] to [8], wherein the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is soluble in an organic solvent.

[0026]

[10] The photosensitive composition according to any one of [1] to [9], which is for use in exposure to actinic radiation having a wavelength of 6.5 to 13.5 nm.

[0027]

[11] A pattern formation method comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive composition according to any one of [1] to

[10] ; irradiating predetermined regions of the photosensitive layer with actinic radiation to perform pattern exposure; and developing the exposed photosensitive layer with a developer to selectively remove exposed or unexposed regions of the photosensitive layer.

[0028]

[12] The pattern formation method according to

[11] , wherein the developer is an organic solvent having a solubility parameter (SP value) of 7.5 to 11. Effect of the Invention

[0029] The photosensitive composition of the present invention has high sensitivity and high resolution, and can satisfy the high sensitivity and high resolution requirements in the ultrafine region. According to the pattern forming method of the present invention using such a photosensitive composition of the present invention, it becomes possible to fully meet the recent demand for finer circuit patterns. According to the present invention, the stability in the solution is improved, and the reproducibility of the pattern formation is also improved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, the embodiments of the present invention will be described in detail, however, the present invention is not limited to the following embodiments and can be practiced in various modified forms within the scope of the gist of the present invention.

[0031] [Photosensitive composition] The photosensitive composition of the present invention is a photosensitive composition containing a tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand. Preferably, the tri-substituted organotin compound is SnR 1 R 2 R 3 (where R 1 ~R 3 are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

[0032] Above R 1 ~R 3 The chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group, specific examples of which include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and other linear alkyl groups.

[0033] R 1 ~R 3 The chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms is preferably a linear or branched chain unsaturated aliphatic hydrocarbon group having 3 to 5 carbon atoms, more preferably a linear alkenyl group. Specific examples thereof include a 1-propenyl group, a 1-butenyl group, a 2-butenyl group, a 1-pentenyl group, a 2-pentenyl group, a 3-pentenyl group, a 1-hexenyl group, a 2-hexenyl group, a 3-hexenyl group, and a 4-hexenyl group.

[0034] Also, R 1 ~R 3The aromatic group having 3 to 10 carbon atoms may be an aromatic heterocyclic group or an aromatic hydrocarbon group. It may also be a monocyclic group or a condensed ring group. The aromatic heterocyclic group may be an aromatic heterocyclic group having 3 to 9 carbon atoms, specifically, a pyrrolyl group, a thiophenyl group, a furanyl group, a pyridinyl group, a pyrrolopyrrolyl group, a thienothiophenyl group, a cyclopentadithiophenyl group, an indolyl group, a benzothiadiazolyl group, a benzpyrrolyl group, etc. The aromatic hydrocarbon group may be an aromatic hydrocarbon group having 6 to 10 carbon atoms, specifically, a phenyl group, a naphthyl group, etc. These may have a substituent such as a methyl group or an ethyl group.

[0035] Among these, R 1 ~R 3 are preferably each independently a linear or branched chain saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, a linear or branched chain unsaturated aliphatic hydrocarbon group having 3 to 5 carbon atoms, or an aromatic hydrocarbon group having 3 to 10 carbon atoms. 1 ~R 3 are each independently a linear or branched chain saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic hydrocarbon group having 3 to 10 carbon atoms, and more preferably R 1 ~R 3 are each independently a chain saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, and particularly preferably R 1 ~R 3 are each independently an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a tert-butyl group. 1 ~R 3 Since these groups have high electron donating properties to Sn, the reactivity when irradiated with actinic radiation tends to be high.

[0036] These R 1 ~R 3 Examples of the substituent that the chain saturated aliphatic hydrocarbon group, the chain unsaturated aliphatic hydrocarbon group, or the aromatic group may have include those exemplified as the following substituent group Q. 1 ~R 3The chain saturated aliphatic hydrocarbon group, the chain unsaturated aliphatic hydrocarbon group, or the aromatic group may have only one of these substituents, or may have two or more of the same or different substituents.

[0037] <Substituent group Q> Examples of the substituent Q include a hydroxy group, a nitro group, a carboxy group, an acyl group, an alkoxy group, an amino group, a sulfonyl group, a phosphonic acid group, etc. For an aromatic group, an alkyl group can be further exemplified as a substituent.

[0038] Among the above-mentioned substituent group Q, R 1 ~R 3 The substituents which the chain-like saturated aliphatic hydrocarbon group, the chain-like unsaturated aliphatic hydrocarbon group or the aromatic group may have are preferably a hydroxy group, an alkoxy group, an amino group, a nitro group, a carboxy group, an acyl group, a sulfonyl group or a phosphonic acid group, more preferably an amino group, an alkoxy group or a hydroxy group. In the case of an aromatic group, an alkyl group is also preferred. However, from the viewpoint of ease of synthesis, R 1 ~R 3 It is preferred that the chain saturated aliphatic hydrocarbon group, the chain unsaturated aliphatic hydrocarbon group or the aromatic group does not have a substituent.

[0039] The tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand according to the present invention preferably contains a compound represented by the following formula (1) (hereinafter sometimes referred to as "compound (1)").

[0040] [ka]

[0041] (In formula (1), R 1 ~R 3are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, each of which may have a substituent; G is not present, or if present, G is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms; M is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, an aromatic group having 3 to 10 carbon atoms, or a substituent represented by the following formula (2), and n is an integer of 1 or more.

[0042] [ka]

[0043] (In formula (2), R 4 ~R 6 are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

[0044] [Compound (1)] R in formula (1) representing compound (1) 1 ~R 3 The chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, the chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or the aromatic group having 3 to 10 carbon atoms may have a substituent such as SnR 1 R 2 R 3 R in 1 ~R 3 The same is true for the preferred ones.

[0045] From the viewpoint of electron donating property, the hydrocarbon bonded to Sn in formula (1) is preferably methylene. 1 ~R 3 are each preferably independently a chain saturated aliphatic hydrocarbon group, i.e., an alkyl group.

[0046] In the formula (1) representing the compound (1), G is not present, or if present, G is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms. Among these, the chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, the chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, and the aromatic group having 3 to 10 carbon atoms are preferably R 1 ~R 3 Examples of the chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, the chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, and the aromatic group having 3 to 10 carbon atoms include those exemplified above.

[0047] Of these, it is preferable that G does not exist from the viewpoint of compound stability and ease of synthesis.

[0048] In formula (1) representing compound (1), M is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, an aromatic group having 3 to 10 carbon atoms, or a substituent represented by the following formula (2).

[0049] [ka]

[0050] (In formula (2), R 4 ~R 6 are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

[0051] M is a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, and is preferably R 1 ~R 3 Examples of the chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, the chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, and the aromatic group having 3 to 10 carbon atoms include those exemplified above. The chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms for M is preferably a linear or branched chain saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, and specific examples thereof include linear or branched alkyl groups such as an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

[0052] Among these, the tin-containing substituent represented by the above formula (2) is preferred as M from the viewpoint of electron donating ability and ease of synthesis. 4 ~R 6 The chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, the chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or the aromatic group having 3 to 10 carbon atoms, which may have a substituent, is preferably R 1 ~R 3 Examples of the chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, the chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, and the aromatic group having 3 to 10 carbon atoms are those exemplified above. 4 ~R 6 are each independently preferably a chain saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic group having 3 to 10 carbon atoms, more preferably a chain saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms, and particularly preferably an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a tert-butyl group. 4 ~R 6 These groups have a high electron donating property to Sn, and therefore tend to have a high reactivity when irradiated with actinic radiation.

[0053] In formula (1) representing compound (1), n ​​is an integer of 1 or more. If n is too large, the solubility in organic solvents tends to decrease. Therefore, n is preferably 1 to 10, more preferably 3 to 10.

[0054] The molecular weight of the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is preferably 300 to 8000. When the molecular weight of compound (1) is 300 or more, relatively high compound stability is obtained. When the molecular weight of compound (1) is 8000 or less, high solubility in organic solvents is obtained. The molecular weight of compound (1) herein refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0055] In addition, the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is preferably soluble in an organic solvent. Examples of the organic solvent include the organic solvents exemplified below as solvents for preparing the photosensitive composition of the present invention. Being soluble in these organic solvents means that it dissolves in the organic solvent at a concentration of 1% by mass or more at a temperature of 25° C. without forming any insoluble matter, and this solubility is more preferably 5% by mass or more.

[0056] Specific examples of tri-substituted organotin compounds having pyridinedicarboxylic acid as a ligand are shown below, but the tri-substituted organotin compounds having pyridinedicarboxylic acid as a ligand according to the present invention are not limited to the following examples.

[0057] [ka]

[0058] [ka]

[0059] Such a tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand can be synthesized specifically by the method described in the Examples section below.

[0060] The photosensitive composition of the present invention may contain only one type of such tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand, or may contain two or more types.

[0061] The content of the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand in the photosensitive composition of the present invention is usually 30 to 100 mass %, preferably 40 to 80 mass %, and particularly preferably 50 to 60 mass %, based on the total mass of the components of the photosensitive composition other than the solvent. When the content of compound (1) in the photosensitive composition is equal to or more than the above lower limit, the composition has reactivity and thus provides exposure sensitivity, whereas when the content is equal to or less than the above upper limit, the composition has good film-forming properties when coated.

[0062] [Photoacid generator] The photosensitive composition of the present invention can also function by containing a photoacid generator that generates an acid upon the action of actinic radiation, together with the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand. Examples of actinic radiation include the bright line spectrum of a mercury lamp, far ultraviolet light represented by an excimer laser, extreme ultraviolet light (EUV light), X-rays, and electron beams. From the viewpoint of resolution, it is preferable that the exposure wavelength is small, and EUV light that emits light with a wavelength of 6.5 to 13.5 nm is preferred.

[0063] Such a photoacid generator that generates an acid when exposed to chemical radiation is not particularly limited as long as it is a known compound, but is preferably a compound that generates an organic acid, such as at least one of sulfonic acid, bis(alkylsulfonyl)imide, and tris(alkylsulfonyl)methide, when exposed to chemical radiation. More preferred examples include compounds represented by the following formulae (ZI), (ZII) and (ZIII).

[0064] [ka]

[0065] In the above formula (ZI), R 201 , R 202 and R 203 each independently represents an organic group. R 201 , R 202 and R 203The organic group as the substituent generally has 1 to 30 carbon atoms, and preferably 1 to 20 carbon atoms.

[0066] R 201 , R 202 and R 203 Examples of the organic group include an aryl group, an alkyl group, and a cycloalkyl group. R 201 , R 202 and R 203 The aryl group generally has 6 to 20 carbon atoms, preferably 6 to 10 carbon atoms, and is more preferably a phenyl group or a naphthyl group, and even more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom, etc. Examples of the heterocyclic structure include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.

[0067] R 201 , R 202 and R 203 The alkyl group and cycloalkyl group are preferably a linear or branched alkyl group having 1 to 10 carbon atoms and a cycloalkyl group having 3 to 10 carbon atoms. The alkyl group is more preferably a 2-oxoalkyl group and an alkoxycarbonylmethyl group. The cycloalkyl group is more preferably a 2-oxocycloalkyl group.

[0068] The 2-oxoalkyl group may be either linear or branched, and preferably includes the above alkyl groups having >C=O at the 2-position. A preferred 2-oxocycloalkyl group is the above cycloalkyl group having >C=O at the 2-position.

[0069] R 201 , R 202 and R 203 may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, a nitro group, or the like. Also, R 201 ~R203 Two of these may be bonded to form a ring structure (preferably a 3- to 15-membered ring), and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. 201 ~R 203 Examples of the group formed by combining two of these include an alkylene group (eg, a butylene group, a pentylene group). Z - represents a non-nucleophilic anion (an anion that has a significantly reduced ability to undergo nucleophilic reactions).

[0070] Examples of non-nucleophilic anions include sulfonate anions (aliphatic sulfonate anions, aromatic sulfonate anions, camphorsulfonate anions, etc.), carboxylate anions (aliphatic carboxylate anions, aromatic carboxylate anions, aralkyl carboxylate anions, etc.), sulfonylimide anions, bis(alkylsulfonyl)imide anions, tris(alkylsulfonyl)methide anions, etc.

[0071] The aliphatic moiety in the aliphatic sulfonate anion and the aliphatic carboxylate anion may be an alkyl group or a cycloalkyl group, and preferred examples include linear or branched alkyl groups having 1 to 30 carbon atoms and cycloalkyl groups having 3 to 30 carbon atoms.

[0072] The aromatic group in the aromatic sulfonate anion and aromatic carboxylate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, or a naphthyl group.

[0073] The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Specific examples of such groups include a nitro group, a halogen atom such as a fluorine atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having 1 to 15 carbon atoms), a cycloalkyl group (preferably having 3 to 15 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbon atoms), an acyl group (preferably having 2 to 12 carbon atoms), an alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), an alkylsulfonyl group (preferably having 1 to 15 carbon atoms), an alkyliminosulfonyl group (preferably having 2 to 15 carbon atoms), an aryloxysulfonyl group (preferably having 6 to 20 carbon atoms), an alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), a cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), an alkyloxyalkyloxy group (preferably having 5 to 20 carbon atoms), and a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms). The aryl group and ring structure of each group may further include an alkyl group (preferably having 1 to 15 carbon atoms) as a substituent.

[0074] The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, or a naphthylbutyl group.

[0075] An example of the sulfonylimide anion is a saccharin anion.

[0076] The alkyl group in the bis(alkylsulfonyl)imide anion and the tris(alkylsulfonyl)methide anion is preferably an alkyl group having a carbon number of 1 to 5. Examples of the substituent of these alkyl groups include a halogen atom, an alkyl group substituted with a halogen atom, an alkoxy group, an alkylthio group, an alkyloxysulfonyl group, an aryloxysulfonyl group, and a cycloalkylaryloxysulfonyl group, and a fluorine atom or an alkyl group substituted with a fluorine atom is preferred. In addition, the alkyl groups in the bis(alkylsulfonyl)imide anion may be bonded to each other to form a ring structure, which increases the acid strength.

[0077] Other non-nucleophilic anions include, for example, phosphorus fluorides (e.g., PF6 - ), boron fluorides (e.g. BF4 - ), antimony fluorides (e.g. SbF6 - ) etc.

[0078] As the non-nucleophilic anion, an aliphatic sulfonate anion in which at least the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion in which a fluorine atom or a group having a fluorine atom is substituted, a bis(alkylsulfonyl)imide anion in which an alkyl group is substituted with a fluorine atom, and a tris(alkylsulfonyl)methide anion in which an alkyl group is substituted with a fluorine atom are preferred. As the non-nucleophilic anion, a perfluoroaliphatic sulfonate anion (more preferably having 4 to 8 carbon atoms), a benzenesulfonate anion having a fluorine atom, and even more preferably a nonafluorobutanesulfonate anion, a perfluorooctane sulfonate anion, a pentafluorobenzenesulfonate anion, and a 3,5-bis(trifluoromethyl)benzenesulfonate anion are more preferred.

[0079] From the viewpoint of acid strength, it is preferable for the pKa of the generated acid to be −1 or less in order to improve sensitivity.

[0080] As a preferred embodiment of the non-nucleophilic anion, there can be mentioned an anion represented by the following formula (AN1).

[0081] [ka]

[0082] In formula (AN1), each Xf independently represents a fluorine atom or an alkyl group substituted with at least one fluorine atom. R A , R B each independently represents a group selected from a hydrogen atom, a fluorine atom, and an alkyl group, A , R B may be the same or different. L represents a divalent linking group, and when a plurality of L's are present, they may be the same or different. A represents a group having a cyclic structure. x represents an integer of 1 to 20, y represents an integer of 0 to 10, and z represents an integer of 0 to 10.

[0083] Formula (AN1) will now be described in further detail. The alkyl group in the alkyl group substituted with a fluorine atom of Xf preferably has a carbon number of 1 to 10, more preferably a carbon number of 1 to 4. In addition, the alkyl group substituted with a fluorine atom of Xf is preferably a perfluoroalkyl group. Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms. Specifically, Xf is a fluorine atom, CF3, C2F5, C3F7, C4F9, C5F 11 , C6F 13 , C7F 15 , C8F 17 , CH2CF3, CH2CH2CF3, CH2C2F5, CH2CH2C2F5, CH2C3F7, CH2CH2C3F7, CH2C4F9, and CH2CH2C4F9, among which a fluorine atom and CF3 are preferred. It is particularly preferred that both Xf are fluorine atoms.

[0084] RA , R B The alkyl group in R may have a substituent (preferably a fluorine atom) and is preferably one having 1 to 4 carbon atoms, more preferably a perfluoroalkyl group having 1 to 4 carbon atoms. A , R B Specific examples of the alkyl group having a substituent include CF3, C2F5, C3F7, C4F9, and C5F 11 , C6F 13 , C7F 15 , C8F 17 , CH2CF3, CH2CH2CF3, CH2C2F5, CH2CH2C2F5, CH2C3F7, CH2CH2C3F7, CH2C4F9, and CH2CH2C4F9, of which CF3 is preferred. R A , R B is preferably a fluorine atom or CF3. x is preferably an integer of 1 to 10, and more preferably an integer of 1 to 5. y is preferably 0 to 4, and more preferably 0. z is preferably an integer of 0 to 5, and more preferably an integer of 0 to 3. The divalent linking group of L is not particularly limited, and examples thereof include -COO-, -OCO-, -CO-, -O-, -S-, -SO-, -SO2-, an alkylene group, a cycloalkylene group, an alkenylene group, or a linking group in which a plurality of these are linked together, and a linking group having a total carbon number of 12 or less is preferred. Among these, -COO-, -OCO-, -CO-, -O-, and -SO2- are preferred, and -COO-, -OCO-, and -SO2- are more preferred.

[0085] The group having a cyclic structure for A is not particularly limited as long as it has a cyclic structure, and examples thereof include an alicyclic group, an aryl group, and a group having a heterocyclic structure (including not only those having aromaticity but also those having no aromaticity). The alicyclic group may be monocyclic or polycyclic, and is preferably a monocyclic cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, or a cyclooctyl group, or a polycyclic cycloalkyl group such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group. Among them, an alicyclic group having a bulky structure with 7 or more carbon atoms, such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, or an adamantyl group, is preferred from the viewpoint of suppressing in-film diffusibility in a post-exposure heating step and improving MEEF. The aryl group includes a benzene ring, a naphthalene ring, a phenanthrene ring, and an anthracene ring. Examples of the group having a heterocyclic structure include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Of these, a furan ring, a thiophene ring, and a pyridine ring are preferred. The group having a cyclic structure may have a substituent, and examples of the substituent include an alkyl group (which may be linear, branched, or cyclic, and preferably has 1 to 12 carbon atoms), an aryl group (which preferably has 6 to 14 carbon atoms), a hydroxy group, an alkoxy group (which preferably has 1 to 12 carbon atoms), a ureido group, a sulfonamide group (which preferably has 0 to 12 carbon atoms), or a group having an ester group, an amide group, a urethane group, a thioether group, or a sulfonate ester group (which preferably has 1 to 12 carbon atoms).

[0086] R 201 , R 202 and R 203Among these, at least one is preferably an aryl group, and more preferably all three are aryl groups. The aryl group may be a phenyl group, a naphthyl group, or a heteroaryl group such as an indole residue or a pyrrole residue. These aryl groups may further have a substituent. Examples of the substituent include a nitro group, a halogen atom such as a fluorine atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having 1 to 15 carbon atoms), a cycloalkyl group (preferably having 3 to 15 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbon atoms), an acyl group (preferably having 2 to 12 carbon atoms), and an alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), but are not limited thereto.

[0087] Also, R 201 ~R 203 When two of these are bonded to form a ring structure, it is preferable that the ring structure be a structure represented by the following formula (A1).

[0088] [ka]

[0089] In formula (A1), R 1a ~R 13a each independently represents a hydrogen atom, a halogen atom, a nitro group, or an organic group. R 1a ~R 13a Among these, it is preferable that 1 to 3 are not hydrogen atoms, and R 9a ~R 13a It is more preferable that any one of these is not a hydrogen atom. Za is a single bond or a divalent linking group. X - is Z in formula (ZI). - is synonymous with.

[0090] R 1a ~R 13aSpecific examples of when is not a hydrogen atom include a halogen atom, a nitro group, a linear, branched, or cyclic alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a carboxyl group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino group (including an anilino group), an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an alkyl and arylsulfonylamino group, an alkylthio group, an arylthio group, a heterocyclic thio group, an alkyl and arylsulfinyl group, an alkyl and arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an aryl and heterocyclic azo group, a phosphinylamino group, a silyl group, a ureido group, and other known organic groups. R 1a ~R 13a When is not a hydrogen atom, it is preferably a linear, branched or cyclic alkyl group substituted with a hydroxyl group.

[0091] The divalent linking group of Za is an alkylene group, an arylene group, a carbonyl group, a sulfonyl group, a carbonyloxy group, a carbonylamino group, a sulfonylamido group, -O-, -S-, an amino group, a disulfide group, -(CH2) n -CO-, -(CH2) n Examples thereof include -SO2-, -CH=CH-, an aminocarbonylamino group, and an aminosulfonylamino group (n is an integer of 1 to 3).

[0092] In addition, R 201 , R 202 and R 203Among these, preferred structures in which at least one is not an aryl group include the compounds exemplified as formulae (I-1) to (I-70) in paragraphs

[0046] and

[0047] of JP-A-2004-233661, and paragraphs

[0040] to

[0046] of JP-A-2003-35948, and the compounds exemplified as formulae (I-1) to (I-70) in U.S. Patent Application Publication No. 2003 / 0224288A1, and the compounds exemplified as formulae (IA-1) to (IA-54) and formulae (IB-1) to (IB-24) in U.S. Patent Application Publication No. 2003 / 0077540A1. An example is a thione structure.

[0093] In formulas (ZII) and (ZIII), R 204 ~R 207 each independently represents an aryl group, an alkyl group, or a cycloalkyl group.

[0094] R 204 ~R 207 As the aryl group, alkyl group, and cycloalkyl group, R 201 ~R 203 The same applies to the aryl group, alkyl group, and cycloalkyl group in the above. R 204 ~R 207 The aryl group, alkyl group, and cycloalkyl group may have a substituent. The substituent may also be R 201 ~R 203 The aryl group, alkyl group and cycloalkyl group may have any of the above groups.

[0095] Z - represents a non-nucleophilic anion, and Z in formula (ZI) - Examples of the non-nucleophilic anions include those similar to those of the above.

[0096] Further examples of the photoacid generator include compounds represented by the following formulas (ZIV), (ZV) and (ZVI).

[0097] [ka]

[0098] In formulae (ZIV) to (ZVI), Ar3 and Ar4 each independently represent an aryl group. R 208 , R 209 and R 210 each independently represents an alkyl group, a cycloalkyl group, or an aryl group. A represents an alkylene group, an alkenylene group, or an arylene group.

[0099] Ar3, Ar4, R 208 , R 209 and R 210 Specific examples of the aryl group include R 201 , R 202 and R 203 Specific examples of the aryl group as mentioned above include the same as those mentioned above. R 208 , R 209 and R 210 Specific examples of the alkyl group and cycloalkyl group include R 201 , R 202 and R 203 Specific examples of the alkyl group and cycloalkyl group as mentioned above include the same as those mentioned above. Examples of the alkylene group of A include alkylene groups having 1 to 12 carbon atoms (e.g., a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, etc.), examples of the alkenylene group of A include alkenylene groups having 2 to 12 carbon atoms (e.g., an ethynylene group, a propenylene group, a butenylene group, etc.), and examples of the arylene group of A include arylene groups having 6 to 10 carbon atoms (e.g., a phenylene group, a tolylene group, a naphthylene group, etc.).

[0100] Among the photoacid generators, particularly preferred examples are given below.

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] The photoacid generator may be used alone or in combination of two or more. When two or more types are used in combination, for example, (1) two types of photoacid generators with different acid strengths are used in combination, or (2) two types of photoacid generators with different sizes (molecular weight or carbon number) of generated acid are used in combination, etc. are preferred. Examples of the embodiment of (1) include a combined use of a fluorine-containing sulfonic acid generator and a tris(fluoroalkylsulfonyl)methide acid generator, a combined use of a fluorine-containing sulfonic acid generator and a non-fluorine-containing sulfonic acid generator, and a combined use of an alkylsulfonic acid generator and an arylsulfonic acid generator. As an embodiment of (2), for example, two types of acid generators whose generated acid anions differ in the number of carbon atoms by 4 or more may be used in combination.

[0107] In particular, the photosensitive composition of the present invention is preferably a photosensitive composition for use with actinic radiation. If the photosensitive composition reacts with actinic radiation, the developing speed in a developer changes, and therefore a pattern can be formed after a certain period of development, which is preferable. As the actinic radiation, a shorter light wavelength is preferable since higher resolution can be obtained, and light with a wavelength of 6.5 to 13.5 nm, that is, EUV light, is preferable. That is, the photosensitive composition of the present invention is preferably a photosensitive composition that reacts with light having a wavelength of 6.5 to 13.5 nm.

[0108] In the photosensitive composition, the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is photosensitive and reacts even when used alone. When a photoacid generator is added, it is photosensitive in synergy with the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand in the photosensitive composition, so that the photosensitivity of the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand can be increased. Therefore, when the photosensitivity of a photosensitive composition composed only of a tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is insufficient for the required specifications, it is preferable to add a photoacid generator. When the photosensitive composition of the present invention contains a photoacid generator, the content of the photoacid generator in the photosensitive composition of the present invention (the total amount when a plurality of photoacid generators are used in combination) is preferably 0.1 to 30 mass %, more preferably 0.5 to 20 mass %, and even more preferably 1 to 15 mass %, based on the total of the components other than the solvent in the photosensitive composition. When the content of the photoacid generator in the photosensitive composition is equal to or more than the above-mentioned lower limit, the effect of enhancing photosensitivity can be obtained, and when the content is equal to or less than the above-mentioned upper limit, good film-forming properties based on the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand can be obtained, which is preferable.

[0109] [solvent] The photosensitive composition of the present invention usually contains a solvent for preparing the composition. The solvent for preparing the photosensitive composition is not particularly limited as long as it dissolves each component, and examples thereof include alkylene glycol monoalkyl ether carboxylates (propylene glycol monomethyl ether acetate (PGMEA; 1-methoxy-2-acetoxypropane) and the like), alkylene glycol monoalkyl ethers (propylene glycol monomethyl ether (PGME; 1-methoxy-2-propanol) and the like), alkyl lactate esters (ethyl lactate, methyl lactate and the like), cyclic lactones (γ-butyrolactone and the like, preferably having 4 to 10 carbon atoms), linear or cyclic ketones (2-heptanone, cyclohexanone and the like, preferably having 4 to 10 carbon atoms), alkylene carbonates (ethylene carbonate, propylene carbonate and the like), alkyl carboxylates (butyl acetate and other alkyl acetates are preferred), and alkoxy alkyl acetates (ethyl ethoxypropionate). Other usable solvents include, for example, the solvents described in US Patent Application Publication No. 2008 / 0248425A1, starting from

[0244] .

[0110] Of the above, alkylene glycol monoalkyl ether carboxylates and alkylene glycol monoalkyl ethers are preferred.

[0111] These solvents may be used alone or in combination of two or more. When two or more are mixed, it is preferable to mix a solvent having a hydroxyl group with a solvent not having a hydroxyl group. As the solvent having a hydroxyl group, an alkylene glycol monoalkyl ether is preferred, and as the solvent not having a hydroxyl group, an alkylene glycol monoalkyl ether carboxylate is preferred.

[0112] The content of the solvent in the total amount of the photosensitive composition of the present invention can be appropriately adjusted depending on the thickness of the pattern film to be formed, etc., but is generally adjusted so that the total concentration of components other than the solvent in the photosensitive composition is 0.5 to 30 mass %, preferably 1.0 to 20 mass %, more preferably 1.5 to 10 mass %, and even more preferably 1.5 to 5 mass %.

[0113] [Surfactants] The photosensitive composition of the present invention preferably further contains a surfactant, preferably a fluorine-based and / or silicone-based surfactant. Examples of surfactants that fall into this category include Megafac F176 and Megafac R08 manufactured by Dainippon Ink and Chemicals, Inc., PF656 and PF6320 manufactured by OMNOVA, Troysol S-366 manufactured by Troy Chemical Co., Ltd., Fluorad FC430 manufactured by Sumitomo 3M Limited, and polysiloxane polymer KP-341 manufactured by Shin-Etsu Chemical Co., Ltd. Moreover, surfactants other than fluorine-based and / or silicon-based surfactants can also be used, more specifically, polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, etc.

[0114] Other known surfactants may be used as appropriate. Examples of usable surfactants include those described in U.S. Patent Application Publication No. 2008 / 0248425A1, paragraphs

[0273] and thereafter.

[0115] The surfactants may be used alone or in combination of two or more kinds. The content of the surfactant is preferably from 0.0001 to 2% by mass, and more preferably from 0.001 to 1% by mass, based on the total of all components other than the solvent in the photosensitive composition.

[0116] [Other additives] In addition to the components described above, the photosensitive composition of the present invention may contain, as appropriate, carboxylic acids, onium salts of carboxylic acids, dissolution inhibiting compounds having a molecular weight of 3,000 or less as described in, for example, Proceeding of SPIE, 2724, 355 (1996), dyes, plasticizers, photosensitizers, light absorbers, antioxidants, and the like. In particular, carboxylic acids are preferably used to improve performance. As the carboxylic acid, aromatic carboxylic acids such as benzoic acid and naphthoic acid are preferred. The content of the carboxylic acid is preferably from 0.01 to 10% by mass, more preferably from 0.01 to 5% by mass, and even more preferably from 0.01 to 3% by mass, based on the total of all components other than the solvent in the photosensitive composition.

[0117] [Method of producing photosensitive composition] The photosensitive composition of the present invention can be produced by dissolving the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand, a photoacid generator used as required, and other components in a solvent for preparation of the solution, and filtering the solution through a filter as required. The filter is preferably made of polytetrafluoroethylene, polyethylene, or nylon with a pore size of 0.1 microns or less, more preferably 0.05 microns or less, and even more preferably 0.03 microns or less. It is presumed that the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand contained in the photosensitive composition exists in a state where the ligand and the tin compound are ionized when dissolved in the preparation solvent.

[0118] [Pattern Forming Method] The pattern formation method of the present invention includes the steps of forming a photosensitive layer on a substrate using the photosensitive composition of the present invention, irradiating predetermined regions of the photosensitive layer with actinic radiation to perform pattern exposure, and developing the exposed photosensitive layer with a developer to selectively remove exposed or unexposed regions of the photosensitive layer.

[0119] [Photosensitive layer formation process] The photosensitive layer can be formed by applying the photosensitive composition of the present invention onto a substrate (e.g., silicon, silicon dioxide coated) such as that used in the manufacture of integrated circuit elements by a suitable application method such as a spinner, and then drying at 50 to 150°C. In this case, if necessary, a commercially available inorganic or organic anti-reflective film can be used, and further, an anti-reflective film can be applied to the lower layer of the resist.

[0120] The tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand contained in the photosensitive layer is presumed to exist in a polymer-like state as shown below, with the pyridinedicarboxylic acid ligand coordinated to two tin atoms.

[0121] [ka]

[0122] [Exposure process] In the present invention, unless otherwise specified, "exposure" includes not only exposure to far ultraviolet light such as mercury lamps and excimer lasers, X-rays, EUV light, and the like, but also drawing with particle beams such as electron beams and ion beams. The exposure can be carried out by irradiating the formed photosensitive layer with chemical radiation through a predetermined mask in a predetermined area to perform pattern exposure, or by irradiating the layer with an electron beam to perform pattern exposure by drawing (direct drawing) without using a mask. The actinic radiation is not particularly limited, but examples include KrF excimer laser, ArF excimer laser, EUV light, and electron beams, with EUV light and electron beams being preferred, and as described above, EUV light that emits light with a wavelength of 6.5 to 13.5 nm being preferred.

[0123] After the exposure, baking (heating) may or may not be performed before development. When baking (heating) is performed, the heating temperature is preferably 50 to 150°C, more preferably 60 to 150°C, and further preferably 80 to 140°C. When baking (heating) is performed, the heating time is preferably from 30 to 300 seconds, more preferably from 30 to 180 seconds, and even more preferably from 30 to 90 seconds. Heating can be carried out by a means provided in a normal exposure / developing machine, and may also be carried out using a hot plate or the like.

[0124] [Development process] After exposure, development is carried out using a developer to selectively remove the exposed or unexposed areas of the photosensitive layer.

[0125] <Developer> As the developer, an organic solvent is preferably used, preferably an organic solvent having a vapor pressure of 5 kPa or less, more preferably 3 kPa or less, and particularly preferably 2 kPa or less at 20° C. By making the vapor pressure of the organic solvent 5 kPa or less, evaporation of the developer on the substrate or in the developing cup is suppressed, improving the temperature uniformity within the surface of the pattern-formed substrate, and as a result, improving the dimensional uniformity within the surface of the pattern-formed substrate.

[0126] As the organic solvent used as the developer, various organic solvents are widely used. For example, at least one solvent selected from ester-based solvents, ketone-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, hydrocarbon-based solvents, and the like can be used. In particular, the developer preferably contains at least one solvent selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, and ether-based solvents.

[0127] Examples of ester-based solvents include alkyl carboxylate solvents such as methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, ethyl-3-ethoxypropionate, propylene glycol diacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, and propyl lactate; alkylene glycol monoalkyl ether carboxylate solvents such as propylene glycol monomethyl ether acetate (PGMEA; also known as 1-methoxy-2-acetoxypropane), ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and propylene glycol monoethyl ether acetate; and more preferably, butyl acetate, amyl acetate, ethyl lactate, and propylene glycol monomethyl ether acetate.

[0128] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, isophorone, and propylene carbonate. Of these, alkyl ketone solvents, such as methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, and cyclohexanone, are more preferred.

[0129] Examples of the alcohol-based solvent include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, hexyl alcohols such as n-hexyl alcohol, heptyl alcohols such as n-heptyl alcohol, octyl alcohols such as n-octyl alcohol, and decanols such as n-decanol; glycol-based solvents such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 1,4-butylene glycol; and ethyl Examples of suitable solvents include alkylene glycol monoalkyl ether solvents such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME; also known as 1-methoxy-2-propanol), ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monoethyl ether; glycol ether solvents such as methoxymethylbutanol and propylene glycol dimethyl ether; and phenol solvents such as phenol and cresol. Of these, 1-hexanol, 2-hexanol, 1-octanol, 2-ethyl-hexanol, propylene glycol monomethyl ether, and cresol are more preferred.

[0130] Examples of the amide solvent that can be used include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, and 1,3-dimethyl-2-imidazolidinone.

[0131] Examples of the ether solvent include the alkylene glycol monoalkyl ether solvents and glycol ether solvents described above, as well as dioxane, tetrahydrofuran, tetrahydropyran, and the like.

[0132] Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane, and dodecane.

[0133] The developer preferably contains one or more solvents selected from alkylene glycol monoalkyl ether carboxylate solvents, alkylene glycol monoalkyl ether solvents, alkyl carboxylate solvents, and alkyl ketone solvents, and more preferably contains one or more solvents selected from propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, ethyl lactate, and butyl acetate.

[0134] The developer used is preferably one containing at least one organic solvent selected from the group consisting of ester solvents having no hydroxyl groups in the molecule, ketone solvents having no hydroxyl groups in the molecule, and ether solvents having no hydroxyl groups in the molecule.

[0135] The organic solvent used as the developer in the present invention is preferably an organic solvent having a solubility parameter (SP value) of 7.5 to 11. An organic solvent having a solubility parameter of 7.5 or more is preferred because it increases the development speed of the dissolved portion, while an organic solvent having a solubility parameter of 11 or less is preferred because it can suppress the development speed of the pattern forming portion. The solubility parameter of the organic solvent in the developer is more preferably 8 to 11.

[0136] In the present invention, the solubility parameter (SP value) is calculated by the method proposed by Fedors et al. Specifically, the value is determined by referring to "POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (pages 147-154)". The SP value is a physical property value determined by the content of hydrophobic and hydrophilic groups in the molecule, and when a mixed solvent is used, it means the value of the mixture.

[0137] Examples of organic solvents that satisfy the above SP values ​​include diethylene glycol monomethyl ether (SP value = 10.7), triethylene glycol monomethyl ether (SP value = 10.7), ethylene glycol monoisopropyl ether (SP value = 10.9), ethylene glycol monobutyl ether (SP value = 10.2), diethylene glycol monobutyl ether (SP value = 10.0), triethylene glycol monobutyl ether (SP value = 10.0), ethylene glycol monoisobutyl ether (SP value = 9.1), ethylene glycol monohexyl ether (SP value = 9.9), diethylene glycol monohexyl ether (SP value = 9.7), diethylene glycol mono 2-ethylhexyl ether (SP value = 9.3), ethylene glycol monoallyl ether (SP value = 10.8), ethylene glycol monophenyl ether (SP value = 10.8), ethylene glycol monobenzyl ether (SP value = 10.9), propylene glycol monomethyl ether (SP value = 10.0), di ... propylene glycol monomethyl ether (SP value = 9.7), tripropylene glycol monomethyl ether (SP value = 9.4), propylene glycol monopropyl ether (SP value = 9.6), dipropylene glycol monopropyl ether (SP value = 9.8), propylene glycol monobutyl ether (SP value = 9.0), dipropylene glycol monobutyl ether (SP value = 9.6), ethylene glycol monomethyl ether acetate (SP value = 10.0), ethylene glycol monoethyl ether acetate ether acetate (SP value = 9.6), ethylene glycol monobutyl ether acetate (SP value = 8.9), diethylene glycol monoethyl ether acetate (SP value = 9.4), diethylene glycol monobutyl ether acetate (SP value = 9.0), propylene glycol monomethyl ether acetate (SP value = 9.4), propylene glycol monoethyl ether acetate (SP value = 9.0), and dipropylene glycol monomethyl ether acetate (SP value = 9.2).

[0138] The organic solvents mentioned above may be used in combination, or may be used in combination with a solvent other than the above or with water.

[0139] The concentration of the organic solvent (total when a plurality of organic solvents are mixed) in the developer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. Particularly preferred is a developer that is essentially made up of an organic solvent. The developer that is essentially made up of an organic solvent includes a developer that contains a small amount of a surfactant, an antioxidant, a stabilizer, an antifoaming agent, etc.

[0140] The water content in the developer is preferably 10% by mass or less, more preferably 5% by mass or less, particularly preferably 3% by mass or less, and most preferably substantially free of water. By keeping the water content at 10% by mass or less, good development characteristics can be obtained.

[0141] If necessary, a suitable amount of a surfactant may be added to the developer used in the present invention. As the surfactant, the same surfactants as those described above for use in the photosensitive composition of the present invention can be used. The amount of the surfactant used is usually from 0.001 to 5% by mass, preferably from 0.005 to 2% by mass, and more preferably from 0.01 to 0.5% by mass, based on the total amount of the developer.

[0142] <Developing method> Development methods that can be applied include, for example, a method in which the substrate is immersed in a tank filled with developer for a certain period of time (dip method), a method in which the developer is piled up on the substrate surface by surface tension and left to stand for a certain period of time (paddle method), a method in which the developer is sprayed onto the substrate surface (spray method), and a method in which the developer is continuously dispensed by scanning a developer dispensing nozzle at a constant speed over a substrate rotating at a constant speed (dynamic dispense method). After the development step, a step of stopping the development while replacing the solvent with another solvent may be carried out. The development time is preferably a time required for the compound (1) and the like in the unexposed or exposed portion of the photosensitive layer to be sufficiently dissolved, and is usually preferably from 10 to 300 seconds, more preferably from 20 to 120 seconds. The temperature of the developer is preferably from 0 to 50°C, and more preferably from 15 to 35°C. The amount of developer can be appropriately adjusted depending on the developing method.

[0143] [Rinse process] The pattern forming method of the present invention may include a step of washing with a rinsing liquid containing an organic solvent after the developing step.

[0144] <Rinse solution> The organic solvent used in the rinse liquid preferably has a vapor pressure of 0.05 kPa to 5 kPa, more preferably 0.1 kPa to 5 kPa, and most preferably 0.12 kPa to 3 kPa at 20° C. By setting the vapor pressure of the organic solvent used in the rinse liquid to 0.05 kPa to 5 kPa, the temperature uniformity within the wafer surface is improved, and further swelling caused by the penetration of the rinse liquid is suppressed, improving the dimensional uniformity within the wafer surface.

[0145] As the rinse solution, various organic solvents can be used. For compound (1), it is preferable to use a rinse solution containing at least one organic solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents, or water. More preferably, after development, a step of washing is performed using a rinse solution containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, and hydrocarbon solvents. Even more preferably, after development, a step of washing is performed using a rinse solution containing at least one organic solvent selected from the group consisting of alcohol solvents and hydrocarbon solvents. Specific examples of the ketone-based solvent, ester-based solvent, alcohol-based solvent, amide-based solvent, ether-based solvent, and hydrocarbon-based solvent used as the rinsing liquid are the same as those described above for the developer. It is particularly preferable to use a rinse solution containing at least one organic solvent selected from the group consisting of monohydric alcohol solvents and hydrocarbon solvents.

[0146] Here, examples of the monohydric alcohol solvent used in the rinsing step after development include linear, branched and cyclic monohydric alcohols. Specifically, 1-butanol, 2-butanol, 3-methyl-1-butanol, tert-butyl alcohol, isopropyl alcohol, cyclopentanol, cyclohexanol and the like can be used, with 1-butanol, 2-butanol, 3-methyl-1-butanol and isopropyl alcohol being preferred. Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents such as octane, decane, and dodecane.

[0147] The above-mentioned components may be used in combination in plural numbers, or may be used in combination with an organic solvent other than those mentioned above.

[0148] The organic solvent may be mixed with water, but the water content in the rinse solution is usually 30% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. Most preferably, the rinse solution does not contain water. By making the water content 30% by mass or less, good development characteristics can be obtained.

[0149] The rinse solution may contain a suitable amount of a surfactant. As the surfactant, the same surfactants as those described above for use in the photosensitive composition can be used, and the amount of the surfactant used is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the rinse solution.

[0150] <Rinse method> In the rinsing step, the developed pattern-formed substrate is washed with a rinsing liquid containing the organic solvent. The cleaning method is not particularly limited, but may be, for example, a method of continuously applying the rinse solution onto a substrate rotating at a constant speed (spin coating method), a method of immersing the substrate in a tank filled with the rinse solution for a certain period of time (dip method), or a method of spraying the rinse solution onto the substrate surface (spray method). Among these, it is preferable to perform the cleaning process by the spin coating method, rotate the substrate at a rotation speed of 2000 to 4000 rpm after cleaning, and remove the rinse solution from the substrate. The rotation time of the substrate can be set within a range that achieves removal of the rinse solution from the substrate depending on the rotation speed, but is usually 10 seconds to 3 minutes. It is preferable to perform rinsing at room temperature. The rinsing time is preferably set so that the developing solvent does not remain on the substrate, and is usually preferably from 10 to 300 seconds, more preferably from 20 to 120 seconds. The temperature of the rinse liquid is preferably from 0 to 50°C, and more preferably from 15 to 35°C. The amount of the rinse solution can be appropriately adjusted depending on the rinse method.

[0151] [Post-processing process] After the development treatment or rinsing treatment, a treatment can be carried out in which the developer or rinsing liquid adhering to the pattern is removed by using a supercritical fluid. Furthermore, after the development treatment, rinsing treatment, or treatment with a supercritical fluid, a heat treatment can be performed to remove the solvent remaining in the pattern. The heating temperature and time are not particularly limited as long as a good resist pattern can be obtained, and are usually 40 to 160°C and 10 seconds to 3 minutes. The heat treatment may be performed multiple times.

[0152] [Application] The photosensitive composition and the pattern forming method of the present invention are suitable for use in the production of semiconductor microcircuits, such as the manufacture of ultra-large scale integration (ULSI) and high-capacity microchips. During the production of semiconductor microcircuits, the resist film on which the pattern is formed is subjected to circuit formation and etching, and the remaining resist film portion is finally removed with a solvent or the like. Therefore, unlike so-called permanent resists used in printed circuit boards and the like, the resist film derived from the photosensitive composition of the present invention does not remain in the final product such as a microchip. EXAMPLES

[0153] The present invention will be described in more detail below with reference to examples, but the contents of the present invention are not limited thereto.

[0154] [Synthesis Example 1] Under a nitrogen atmosphere, tributyltin chloride (24.0 g, 73.7 mmol) dissolved in tetrahydrofuran (550 ml) was placed in a reaction vessel, 16 M aqueous sodium hydroxide solution (360 ml) was added, and the mixture was stirred at room temperature overnight. Ethyl acetate was added, and the mixture was separated, and the aqueous layer was re-extracted with ethyl acetate. The combined organic layer was washed successively with water and saturated saline, dried over magnesium hydroxide, filtered, and concentrated under reduced pressure to obtain bis(tributyltin) oxide (21.7 g, 99% yield).

[0155] In a nitrogen atmosphere, bis(tri-n-butyltin) oxide (11.7 g, 19.6 mmol, 1.0 equivalent), 2,5-pyridinedicarboxylic acid (3.28 g, 19.6 mmol, 1.0 equivalent), toluene (1460 ml), and methanol (290 ml) were placed in a reaction vessel and refluxed for 17 hours. The mixture was cooled to room temperature, filtered to remove insoluble matter, and the filtrate was concentrated under reduced pressure to obtain 14.8 g of crude product. Three times the amount of dichloromethane (45 ml) was added, and the insoluble matter was removed by suction filtration. The filtrate was concentrated under reduced pressure, washed with diisopropyl ether, and suction filtered to recover the solid on the filter paper, obtaining compound 1 (2,5-pyridinedicarboxylic acid coordinated tri-n-butyltin) (10.41 g, yield 71%) of the following structure. 1 H NMR(CDCl3,ppm):0.82(t,18H,CH3),1.39-1.83(m,36H,CH2CH2CH2),7.45-7.95(pyridine). 119 SnNMR(CDCl3,ppm):δ-129.6 Also, 1 From the proton ratio of H NMR, it was found that compound 1 was composed of 2,5-pyridinedicarboxylic acid and tri-n-butyltin in a ratio of 3:4.

[0156] [ka]

[0157] Here, the ratio of x to y in the above structure is 4:3.

[0158] [Synthesis Example 2] In a nitrogen atmosphere, bis(tri-n-butyltin)oxide (10.0 g, 16.8 mmol, 1.0 equivalent), 2,6-pyridinedicarboxylic acid (2.80 g, 16.8 mmol, 1.0 equivalent), toluene (1250 ml), and methanol (250 ml) were placed in a reaction vessel and refluxed for 16 hours with stirring. The mixture was cooled to room temperature, filtered to remove insoluble matter, and the filtrate was concentrated under reduced pressure. Acetonitrile (100 ml) was added and concentrated under reduced pressure to obtain compound 2 (9.56 g, 73%) of the following structure. 1 H NMR(CDCl3,ppm):δ8.98(s,H2O);7.56-8.07(pyridine),0.86(t,36H,CH3),1.31-1.86(m,72H,CH2CH2CH2),1.96(s,3H,CH3CN). 119 Sn NMR(CDCl3,ppm):δ-116.8,82.5. Also, 1 From the proton ratio of H NMR, it was found that compound 2 was composed of 2,6-pyridinedicarboxylic acid and tri-n-butyltin in a ratio of 3:4.

[0159] [ka]

[0160] [Examples 1-2] <Preparation of photosensitive composition (resist solution)> Compound 1 synthesized as described above was dissolved in cyclohexanone, and compound 2 was dissolved in ethyl lactate at a concentration of 2.5 mass %, respectively, and filtered through a 0.2 μm filter to prepare a resist solution.

[0161] <Resist film formation and pattern drawing> The prepared resist solution was applied to a pattern forming substrate (silicon wafer) by spin coating to form a resist film with a thickness of about 50 nm. The resist film thus obtained was subjected to pattern drawing using an electron beam lithography system (electron beam accelerating voltage: 100 keV) after baking at 90°C for 90 seconds or without post-exposure heating.

[0162] <Development> After the pattern was written, development was performed with cyclohexanone (vapor pressure at 20° C.: 0.47 kPa, SP value: 8.2) (25° C., 60 seconds) to obtain a negative pattern.

[0163] <Sensitivity measurement> Electron beam writing was performed with different doses of irradiation, and the film thickness of the developed pattern was measured with a contact step gauge. The dose of electron beam irradiation at which the amount of change in film thickness was maximized was determined as the sensitivity. The results are shown in Table 1.

[0164] [Table 1]

[0165] From the results in Table 1, it was found that the sensitivity was ranked in the order of Example 1, followed by Example 2, with Example 1 being higher.

[0166] <Resolution evaluation> The resolution of Example 1 was evaluated using an electron beam lithography device. The resolution was evaluated by drawing line and space (line:space=1:1) patterns with hp (half pitch) of 100 nm, hp 50 nm, and hp 30 nm, developing the patterns, and observing each pattern with a scanning electron microscope to determine whether the drawn patterns were present or not (◯ / ×). The results are shown in Table 2.

[0167] [Comparative Example 1] Polyhydroxystyrene (PHS, weight average molecular weight 11000) manufactured by Aldrich was dissolved in propylene glycol monomethyl ether acetate at a concentration of 2% by mass, and the solution was filtered through a 0.2 μm filter to prepare a resist solution.

[0168] [Comparative Example 2] Polystyrene (PS, weight average molecular weight 4000) manufactured by Aldrich was dissolved in propylene glycol monomethyl ether acetate at a concentration of 2% by mass, and the solution was filtered through a 0.2 μm filter to prepare a resist solution.

[0169] The resist solutions of Comparative Examples 1 and 2 were subjected to a resolution evaluation in the same manner as in Example 1, and the results are shown in Table 2.

[0170] [Table 2]

[0171] As is clear from the above results, the use of the photosensitive composition of the present invention can improve the resolution. In addition, considering the photosensitive reaction mechanism of lithography resist, it can be inferred that the resolution is also high with respect to exposure to EUV light (13.5 nm).

[0172] As described above, the photosensitive composition of the present invention has excellent dissolution stability, and can achieve good pattern shape and reproducibility in ultrafine regions, as well as good line width roughness. Therefore, it will be possible to form resist patterns with reduced roughness even in future EUV lithography, and the industrial value of the composition will be enormous.

Claims

1. A photosensitive composition comprising a tri-substituted organotin compound having a pyridinedicarboxylic acid as a ligand.

2. The tri-substituted organotin compound is SnR １ R ２ R ３ and R １ ~R ３ each independently represents a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

3. 3. The photosensitive composition according to claim 1, wherein the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is a compound represented by the following formula (1): 【Chemistry 1】 (In formula (1), R １ ~R ３ are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent; G is absent, or if present, G is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms; M is a hydrogen atom, a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, an aromatic group having 3 to 10 carbon atoms, or a substituent represented by the following formula (2), and n is an integer of 1 or more. 【Chemistry 2】 (In formula (2), R ４ ~R ６ are each independently a chain saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, a chain unsaturated aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an aromatic group having 3 to 10 carbon atoms, which may have a substituent.

4. The R １ ~R ３ 4. The photosensitive composition according to claim 2, wherein the hydrocarbon bonded to Sn in the formula (I) is methylene.

5. 5. The photosensitive composition according to claim 3, wherein n in formula (1) is 1 to 10.

6. The R １ ~R ３ The photosensitive composition according to any one of claims 2 to 5, wherein each of the groups independently represents a linear saturated aliphatic hydrocarbon group having 1 to 5 carbon atoms.

7. 7. The photosensitive composition according to claim 1, further comprising a photoacid generator which generates an acid by the action of actinic radiation.

8. 8. The photosensitive composition according to claim 1, wherein the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand has a molecular weight of 300 to 8,000.

9. 9. The photosensitive composition according to claim 1, wherein the tri-substituted organotin compound having pyridinedicarboxylic acid as a ligand is soluble in an organic solvent.

10. The photosensitive composition according to any one of claims 1 to 9, which is for use with actinic radiation having a wavelength of 6.5 to 13.5 nm.

11. 11. A pattern forming method comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive composition according to claim 1; irradiating predetermined regions of the photosensitive layer with actinic radiation to perform pattern exposure; and developing the exposed photosensitive layer with a developer to selectively remove exposed or unexposed regions of the photosensitive layer.

12. 12. The pattern formation method according to claim 11, wherein the developer is an organic solvent having a solubility parameter (SP value) of 7.5 to 11.

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