JP2005075767A - Photoresist base and method for refining the same, and photoresist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoresist base enabling ultra-fine processing with extreme ultraviolet radiation or the like, and to provide a method for refining the same, and to provide a photoresist composition. <P>SOLUTION: The photoresist base comprises an extreme ultraviolet radiation-reactive organic compound of the general formula(1)( wherein, A is a central structure composed of 1-50C aliphatic group(s), 6-50C aromatic group(s), organic group(s) containing these groups at the same time or a cyclic-structured organic group where these groups are repeated; B to D are each an extreme ultraviolet radiation-reactive group, a group reactive to the action of a chromophore active to extreme ultraviolet radiation, a 1-50C aliphatic group or 6-50 aromatic group each containing these reactive groups, an organic group containing the above aliphatic or aromatic group at the same time or a substituent of branched structure; X to Z are each a single bond or ether linkage; l to n are each an integer of 0-5 meeting the relationship:l+m+n≥1; wherein A to D may each contain a heteroatom-bearing substituent ). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photoresist base material used in electrical / electronic fields such as semiconductors and optical fields, a purification method thereof, and a photoresist composition.

  Lithography using extreme ultraviolet light (EUV), vacuum ultraviolet light, electron beam, ion beam, etc., especially lithography using extreme ultraviolet light or electron beam is a highly productive ultra-fine processing method in the manufacture of semiconductors and the like. Useful. In addition, it is required to develop a high-sensitivity and high-resolution photoresist corresponding to processing of 100 nm or less, particularly 50 nm or less by extreme ultraviolet light or an electron beam. It is indispensable to improve the sensitivity of the photoresist used in these lithography from the viewpoint of the productivity and resolution of the desired fine pattern.

  Examples of the photoresist used at the time of ultrafine processing using extreme ultraviolet light include chemically amplified polyhydroxystyrene-based photoresists used at the time of ultrafine processing using a known KrF laser. This resist is known to be capable of fine processing up to about 50 nm (for example, see Non-Patent Document 1). However, with this resist, when a pattern of 50 nm or less, which is the greatest merit of ultra-fine processing using extreme ultraviolet light, is created, there are problems such as low contrast, large line edge roughness, low resist sensitivity, and many resist outgases. Therefore, it cannot be said that the original performance of extreme ultraviolet light is sufficiently extracted. Against this background, it has been demanded to develop a higher performance extreme ultraviolet light photoresist.

  In response to this demand, a method using a chemically amplified positive photoresist having a higher concentration of photoacid generating compound than other resist compounds has been proposed (see, for example, Patent Document 1). However, in this method, in the examples, a substrate comprising a terpolymer consisting of hydroxystyrene / styrene / t-butyl acrylate, at least about 5% by weight of di (t-butylphenyl) iodonium ortho-tri in total solids. Specific results for photoacid generators composed of fluoromethylsulfonate, photoresists composed of tetrabutylammonium hydroxide lactate and ethyl lactate, such as sensitivity, line edge roughness, and production line width when using extreme ultraviolet light Was not illustrated. Therefore, for these results, it was considered that the processing up to 100 nm exemplified in the case of using an electron beam was the limit from the viewpoint of line edge roughness. This is presumed to be caused by the excessive reaction of the substrate due to the excessive addition of the photoacid generator, that is, the excessive diffusion of the acid to the non-exposed area.

  On the other hand, microfabrication with an electron beam is inferior to extreme ultraviolet light in terms of productivity, but it is not necessary to use a mask, and is suitable for manufacturing a special semiconductor with a small number of lifetime production. Various types of positive and negative photoresists for electron beams have been proposed. If an electron beam irradiation apparatus having a sufficiently small converging radius is used, it is possible to create an isolated line having a width of 8 nm. However, the line edge roughness at that time cannot be said to be sufficiently small because the molecular shape of the polymer compound contained as the base material is reflected.

With the progress of miniaturization of semiconductor processing, the required value of line edge roughness has become stricter. However, as described above, in the conventional photoresist using a polymer compound as a base material, the molecular shape is reflected in the line edge roughness. Therefore, in the ultrafine processing region of 50 nm or less, for example, processing with the line edge roughness suppressed to 3 nm or less is when a polymer compound having a molecular size of about several tens of nm is used as a substrate. Was theoretically difficult.
“Next Generation EUVL (Extreme Ultra-Violet Lithography) Technology Research”, 2000 Survey Report New Energy and Industrial Technology Development Organization Consignment Project JP 2002-055557 A

The present invention has been made in view of the above circumstances, and provides a photoresist base material, a purification method thereof, and a photoresist capable of performing ultrafine processing with extreme ultraviolet light or the like with high sensitivity, high contrast, and low line edge roughness. An object is to provide a composition.
In order to achieve the above object, the present inventors have made extensive studies, and as a result, they have been used in the synthesis, and remain basic, such as ammonia, alkali metal ions, alkaline earth metal ions, etc. that are mixed in from the human body or the environment. The inventors have found out that impurities are caused by a decrease in sensitivity of the photoresist.
In particular, in the case of photoresist, when the extreme ultraviolet light has a high absorbance when passing through the photoresist layer and the intensity of the light source is low, the photoacid generator may be highly concentrated. If even a small amount of impurities is mixed, the proton generated from the acid generator is neutralized, so that the desired reaction does not proceed.
The present inventors have synthesized a novel excellent photoresist base material and have already filed an application in Japanese Patent Application No. 2003-112458. Furthermore, the present inventors have found that the sensitivity is dramatically increased when these photoresist substrates are purified to remove basic impurities to a certain value or less, and the present invention has been completed.

［式中、Ａは、炭素数１〜５０の脂肪族基、炭素数６〜５０の芳香族基、これら脂肪族基及び芳香族基を同時に含む有機基、又はこれらの基が繰り返された環状構造の有機基からなる中心構造であり、Ｂ、Ｃ及びＤは、相互に独立な、極端紫外光反応性基、極端紫外光に活性なクロモフォアの作用に対し反応性を有する基、又はこれらの反応性基を含む、炭素数１〜５０の脂肪族基、炭素数６〜５０の芳香族基、これら脂肪族基及び芳香族基を同時に含む有機基、分岐構造からなる置換基であり、Ｘ、Ｙ及びＺは、相互に独立な、単結合又はエーテル結合であり、ｌ、ｍ及びｎは、相互に独立な、ｌ＋ｍ＋ｎ≧１を満たす０〜５の整数であり、Ａ、Ｂ、Ｃ及びＤは、ヘテロ原子を有する置換基を含んでいてもよい。］ According to the first aspect of the present invention, there is provided a photoresist base material comprising an extreme ultraviolet light-reactive organic compound represented by the following general formula (1), wherein the basic impurity content is 10 ppm or less. .

[In the formula, A is an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing these aliphatic groups and aromatic groups simultaneously, or a cyclic structure in which these groups are repeated. A central structure consisting of organic groups of the structure, B, C and D are mutually independent extreme ultraviolet light reactive groups, groups reactive to the action of chromophores active in extreme ultraviolet light, or these An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing these aliphatic groups and an aromatic group at the same time, and a substituent having a branched structure, , Y and Z are mutually independent single bonds or ether bonds, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D may contain a substituent having a hetero atom. ]

［式中、Ａは、

で表される有機基であり、
Ｂ、Ｃ及びＤは、相互に独立な、

［Ｐは、炭素数６〜２０の（ｒ＋１）価の芳香族基であり、Ｑは、炭素数４〜３０の有機基であり、ｒは、１〜１０の整数であり、ｓは、０〜１０の整数である。］
で表される有機基であり、ｌ＋ｍ＋ｎ＝３又は８である。］ According to the 2nd aspect of this invention, the photoresist base material which consists of a radiation sensitive organic compound represented by following General formula (1) whose content of a basic impurity is 10 ppm or less is provided.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ]

  According to the third aspect of the present invention, there is provided a photoresist composition comprising a solid containing the above-mentioned photoresist base material and a solvent.

［式中、Ａは、炭素数１〜５０の脂肪族基、炭素数６〜５０の芳香族基、前記脂肪族基及び芳香族基を同時に含む有機基、又はこれらの基が繰り返された環状構造の有機基からなる中心構造であり、Ｂ、Ｃ及びＤは、相互に独立な、極端紫外光反応性基、極端紫外光に活性なクロモフォアの作用に対し反応性を有する基、又はこれらの反応性基を含む、炭素数１〜５０の脂肪族基、炭素数６〜５０の芳香族基、前記脂肪族基及び芳香族基を同時に含む有機基、分岐構造からなる置換基であり、Ｘ、Ｙ及びＺは、相互に独立な、単結合又はエーテル結合であり、ｌ、ｍ及びｎは、相互に独立な、ｌ＋ｍ＋ｎ≧１を満たす０〜５の整数であり、Ａ、Ｂ、Ｃ及びＤは、ヘテロ原子を有する置換基を含んでいてもよい。］ According to the fourth aspect of the present invention, a photoresist base is prepared by washing a photoresist base material composed of an extreme ultraviolet light-reactive organic compound represented by the following general formula (1) with an acidic aqueous solution and treating it with an ion exchange resin. A method for purifying the material is provided.

[In the formula, A represents an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, or a cyclic structure in which these groups are repeated. A central structure consisting of organic groups of the structure, B, C and D are mutually independent extreme ultraviolet light reactive groups, groups reactive to the action of chromophores active in extreme ultraviolet light, or these An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, and a substituent having a branched structure, , Y and Z are mutually independent single bonds or ether bonds, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D may contain a substituent having a hetero atom. ]

［式中、Ａは、

で表される有機基であり、
Ｂ、Ｃ及びＤは、相互に独立な、

［Ｐは、炭素数６〜２０の（ｒ＋１）価の芳香族基であり、Ｑは、炭素数４〜３０の有機基であり、ｒは、１〜１０の整数であり、ｓは、０〜１０の整数である。］
で表される有機基であり、ｌ＋ｍ＋ｎ＝３又は８である。］ According to the fifth aspect of the present invention, a photoresist substrate comprising a radiation sensitive organic compound represented by the following general formula (1) is washed with an acidic aqueous solution and treated with an ion exchange resin. A purification method is provided.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ]

［式中、Ａは、炭素数１〜５０の脂肪族基、炭素数６〜５０の芳香族基、前記脂肪族基及び芳香族基を同時に含む有機基、又はこれらの基が繰り返された環状構造の有機基からなる中心構造であり、Ｂ、Ｃ及びＤは、相互に独立な、極端紫外光反応性基、極端紫外光に活性なクロモフォアの作用に対し反応性を有する基、又はこれらの反応性基を含む、炭素数１〜５０の脂肪族基、炭素数６〜５０の芳香族基、前記脂肪族基及び芳香族基を同時に含む有機基、分岐構造からなる置換基であり、Ｘ、Ｙ及びＺは、相互に独立な、単結合又はエーテル結合であり、ｌ、ｍ及びｎは、相互に独立な、ｌ＋ｍ＋ｎ≧１を満たす０〜５の整数であり、Ａ、Ｂ、Ｃ及びＤは、ヘテロ原子を有する置換基を含んでいてもよい。］ According to the sixth aspect of the present invention, radiation of a photoresist base material composed of an extreme ultraviolet light-reactive organic compound represented by the following general formula (1) by setting the content of basic impurities to 10 ppm or less. A sensitivity enhancement method is provided.

[In the formula, A represents an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, or a cyclic structure in which these groups are repeated. A central structure consisting of organic groups of the structure, B, C and D are mutually independent extreme ultraviolet light reactive groups, groups reactive to the action of chromophores active in extreme ultraviolet light, or these An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, and a substituent having a branched structure, , Y and Z are mutually independent single bonds or ether bonds, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D may contain a substituent having a hetero atom. ]

［式中、Ａは、

で表される有機基であり、
Ｂ、Ｃ及びＤは、相互に独立な、

［Ｐは、炭素数６〜２０の（ｒ＋１）価の芳香族基であり、Ｑは、炭素数４〜３０の有機基であり、ｒは、１〜１０の整数であり、ｓは、０〜１０の整数である。］
で表される有機基であり、ｌ＋ｍ＋ｎ＝３又は８である。］ According to the seventh aspect of the present invention, the radiation sensitivity of a photoresist substrate made of a radiation-sensitive organic compound represented by the following general formula (1) is improved by setting the content of basic impurities to 10 ppm or less. A method is provided.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ]

  According to an eighth aspect of the present invention, there is provided a microfabrication method by lithography using the above photoresist composition.

  According to a ninth aspect of the present invention, there is provided a semiconductor device manufactured using the above photoresist composition.

［式中、Ａは、

で表される有機基であり、
Ｂ、Ｃ及びＤは、相互に独立な、

［Ｐは、炭素数６〜２０の（ｒ＋１）価の芳香族基であり、Ｑは、炭素数４〜３０の有機基であり、ｒは、１〜１０の整数であり、ｓは、０〜１０の整数である。］
で表される有機基であり、ｌ＋ｍ＋ｎ＝３又は８である。］ According to the tenth aspect of the present invention, there is provided an organic compound represented by the following general formula (1), wherein the content of basic impurities is 10 ppm or less.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ]

［式中、Ａは、

で表される有機基であり、
Ｂ、Ｃ及びＤは、相互に独立な、

［Ｐは、炭素数６〜２０の（ｒ＋１）価の芳香族基であり、Ｑは、炭素数４〜３０の有機基であり、ｒは、１〜１０の整数であり、ｓは、０〜１０の整数である。］
で表される有機基であり、ｌ＋ｍ＋ｎ＝３又は８である。］ According to the eleventh aspect of the present invention, there is provided a method for purifying an organic compound in which an organic compound represented by the following general formula (1) is washed with an acidic aqueous solution and treated with an ion exchange resin.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ]

  According to the present invention, it is possible to provide a photoresist base material, a purification method thereof, and a photoresist composition capable of performing ultrafine processing with extreme ultraviolet light or the like with high sensitivity, high contrast, and low line edge roughness. .

Hereinafter, the photoresist base material of the present invention will be described.
The photoresist base material of the present invention comprises an organic compound represented by the following general formula (1). This compound is radiation sensitive.
Here, the radiation means ultraviolet light having a wavelength of 10 to 300 nm, specifically, extreme ultraviolet light and vacuum ultraviolet light, an electron beam, an ion beam, or the like.
The compound used in the present invention is preferably extreme ultraviolet light and / or electron beam reactive, more preferably extreme ultraviolet light reactive. These compounds can also react with other general radiation (for example, infrared light, visible light ultraviolet light, ultraviolet light (g-ray, i-ray, etc.), X-ray, etc.).

[In the formula, A is an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing these aliphatic groups and aromatic groups simultaneously, or a cyclic structure in which these groups are repeated. B, C and D are independent of each other, a radiation-sensitive group, a group reactive to the action of a radiation-active chromophore, or these reactive groups. An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group simultaneously containing these aliphatic groups and aromatic groups, and a substituent having a branched structure, X, Y and Z Is a single bond or an ether bond independent of each other, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D are heterogeneous. It may contain a substituent having an atom. ]

  In the central structure A, examples of the aliphatic group having 1 to 50 carbon atoms include linear aliphatic groups such as a methyl group, a methylene group, an ethyl group, and a dodecyl group, an isopropyl group, an isobutyl group, and a tert-butyl group. And a branched aliphatic group such as a branched aliphatic group, a cyclohexyl group, a norbornenyl group, an adamantyl group, a diadamantyl group, and a biadamantyl group. Examples of the aromatic group having 6 to 50 carbon atoms include a phenyl group, a phenylene group, a naphthyl group, a naphthylene group, a fluorene group, and an alkyl aromatic group. Examples of the organic group containing an aliphatic group and an aromatic group at the same time include a group containing an adamantyl group and a methylene group, an adamantyl group and a phenylene group at the same time. Examples of the organic group having a cyclic structure in which these groups are repeated include calixarenes such as calix- [4] -resorcinalene. Examples of the substituent having a hetero atom include 1-tetrahydropyranyl group, 1-tetrahydrofuranyl group, acetal group such as methoxymethyl group, ethoxyethyl group, carbonyl group, hydroxyl group, carboxyl group, t-butyl ester group , Alkoxy groups, cyano groups, amino groups, amide groups, imide groups, pyridyl groups, and the like. The central structure A may be composed of a single organic group, or may be composed of a group in which a plurality of the same or different organic groups are bonded.

Specific examples of the central structure A include the organic groups shown below.

B to D are substituents (reactive groups) that are reactive when irradiated with radiation, groups that are reactive with respect to the action of radiation-active chromophore, or substituents containing these. In these substituents B to D, as an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing these aliphatic group and aromatic group at the same time, and a substituent having a hetero atom Is the same group as in the central structure A. In addition, examples of the substituent having a branched structure include groups represented by dendrons. The substitution position on the central structure A of the substituents B to D is not particularly limited.
Of B, C and D, at least one is preferably a hydrogen atom.

［Ａｒは、ＲＯ−及び／又はＲＯＣＯ−（Ｒ、ＲＯ−及びＲＯＣＯ−は、感放射線性基又は放射線に活性なクロモフォアの作用に対し反応性を有する基である）で置換されたフェニル基又はナフチル基である。］ Specific examples of the substituents B to D include organic groups shown below, and a radiation-sensitive group described later, or groups R, RO-, and ROCO-, which are reactive to the action of a radiation-active chromophore. .

[Ar is a phenyl group substituted with RO- and / or ROCO- (R, RO- and ROCO- are groups that are reactive to the action of a radiation-sensitive group or a radiation-active chromophore) or Naphthyl group. ]

  Specific examples of the compound used in the present invention include compounds of the following formulas (2) to (17) and their positional isomers.

  In the above formulas (2) to (14), the substituent Ar includes a group R, RO- and ROCO- (described later) having reactivity to the action of a radiation-sensitive group or radiation-active chromophore. Any of these can be suitably used. Specific examples include the substituents shown below and substituents of these positional isomers. Substituent Ar may be used alone or in combination of two or more thereof within a range not impairing the effects of the present invention.

  In the above formulas (15) to (17) and the substituent Ar, the substituents R, RO-, and ROCO- are groups that are reactive to the action of a radiation-sensitive group or radiation-active chromophore. Any of these can be suitably used. Specifically, as R, for example, hydrogen; tertiary hydrocarbon group such as tert-butyl group and adamantyl group; substituent such as tert-butoxycarbonyl group where RO-group constitutes a carbonate group; methoxymethyl In addition to the substituent in which the RO- group constitutes an acetal group, such as a group, 1-ethoxyethyl group, 1-phenoxyethyl group, the following substituents are shown as R. The substituent R may be used singly or in combination of two or more, as long as the effects of the present invention are not impaired.

［式中、Ｒ’、Ｒ’’及びＲ’’’は、相互に独立な、炭素数１〜１０の脂肪族炭化水素基又は芳香族基であり、Ｐは、炭素数６〜２０の（ｒ＋１）価の芳香族基であり、Ｑは、炭素数４〜３０の有機基であり、ｒは、１〜１０の整数であり、ｓは、０〜１０の整数である。］

Wherein R ′, R ″ and R ′ ″ are mutually independent aliphatic hydrocarbon groups or aromatic groups having 1 to 10 carbon atoms, and P is a group having 6 to 20 carbon atoms ( r + 1) valent aromatic group, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is an integer of 0 to 10. ]

で表される有機基において、芳香族基Ｐ、有機基Ｑの炭素数は、好ましくは、それぞれ６〜１０、４〜２０であり、ｒ、ｓは、それぞれ好ましくは、１〜５、０〜３である。
具体的には、以下の有機基が挙げられる。

In the organic group represented by the formula (1), the carbon number of the aromatic group P and the organic group Q is preferably 6 to 10 and 4 to 20 respectively, and r and s are preferably 1 to 5 and 0 to 0, respectively. 3.
Specific examples include the following organic groups.

The compound used in the present invention has a content of basic impurities (for example, alkali metal ions such as ammonia, Li, Na and K, alkaline earth metal ions such as Ca and Ba, etc.) of 10 ppm or less, preferably 2 ppm or less. is there.
By making the content of basic impurities 10 ppm or less, the sensitivity of the photoresist base material made of this compound to radiation is dramatically improved, and as a result, a fine pattern by lithography of the photoresist composition is suitably produced. It becomes possible.

The compound used in the present invention is preferably in an amorphous state at room temperature, and the average diameter of the molecules is smaller than the desired pattern size, preferably 5 nm or less, more preferably 2 nm or less.
The mean diameter is the structure obtained by optimizing the structure using the AM1 method of the semi-empirical orbit method program package MOPAC97, and assuming that the volume based on the van der Waals radius of the space occupied by the structure is a true sphere. Is defined as the diameter of

The compound used in the present invention can be synthesized by combining known reactions. At this time, when an impurity is contained in the compound, it can be appropriately separated and purified by a known method.
In the present invention, this compound is washed with an acidic aqueous solution, treated with an ion exchange resin and purified, whereby the content of basic impurities can be reduced to 10 ppm or less. At this time, the types of the acidic aqueous solution and the ion exchange resin can be appropriately selected according to the amount and type of basic impurities to be removed or the type of compound to be treated. In the present invention, an aqueous acetic acid solution having a concentration of 0.01 to 10 mol / liter is preferably used as the acidic aqueous solution, and a cation exchange resin is used as the ion exchange resin. Particularly preferably, after washing with an aqueous acetic acid solution as an acidic aqueous solution, the solution is purified by treatment with a cation exchange resin.

Such a compound is useful as a photoresist base material, particularly as a photoresist base material used in ultra-fine processing using extreme ultraviolet light or an electron beam.
That is, the compound used in the present invention is in an amorphous state as described above under the conditions for use as a photoresist substrate, usually at room temperature. It is preferable in terms of strength as a resist film.
Further, as described above, the compound used in the present invention has an average molecular diameter larger than the line edge roughness value required for a desired pattern size, specifically, a size of 100 nm or less, particularly 50 nm or less. small. Therefore, when used as a substrate, the line edge roughness is suppressed to 2 nm, preferably 1 nm or less (3σ) when used for processing of 20 to 50 nm, which is a feature of ultrafine processing using extreme ultraviolet light or an electron beam. be able to.

  When such a compound is used as a photoresist base material, it may be used alone or in combination of two or more without departing from the effects of the present invention. Furthermore, a compound formed by combining a plurality of substituents with any substituent may be used alone, or two or more compounds may be used in combination as long as the effects of the present invention are not impaired.

The photoresist base material of the present invention can be used as one component of a photoresist composition.
The composition of the present invention is a liquid composition containing a solid content containing a photoresist base material comprising the above-described compound and a solvent for dissolving the solid content. In the present invention, it is necessary to form a liquid composition in order to uniformly apply a photoresist to a substrate to be subjected to ultrafine processing.

  The base material containing the radiation-sensitive group of the present invention contains a chromophore active against radiation, and can exhibit the ability as a photoresist alone, so an additive is particularly added to the solid content. Although it is not necessary, if it is better to enhance the performance as a photoresist, or when using a substrate containing a group reactive to the action of radiation-active chromophore, etc., if necessary, As the chromophore, a photoacid generator (PAG), a photobase generator (PBG), or the like can be added.

  As the PAG, in addition to known compounds exemplified by the following structures, compounds having the same action can be generally used. These can be appropriately selected according to the type of substrate, the shape and size of the desired fine pattern, and the like.

  As PBG, in addition to known compounds exemplified by the following structures, compounds having the same action can be generally used. These can be appropriately selected according to the type of substrate, the shape and size of the desired fine pattern, and the like. In addition, when using PBG as a chromophore, the amount of basic impurities contained in the base material is taken into consideration, and the amount of PBG is appropriately adjusted so that the reactivity cannot be controlled due to excessive PBG addition. Can be adjusted.

  In the present invention, in addition to PAG and PBG, a base such as tetrabutylammonium hydroxide and a salt thereof, an anti-light agent, a plasticizer, a speed accelerator, and a photosensitizer as long as the effect is not impaired. Further, a sensitizer, an acid growth functional material, an etching resistance enhancer, and the like can be added.

  Each component in the solid content may be a single component, a mixture of components having the same or different functions, or a mixture of precursors of these components. Moreover, about the composition of solid content, and the compounding ratio of each component in solid content, it can adjust suitably according to the shape, size, etc. of a desired fine pattern. In general, the mixing ratio may be the same as that of a conventional photoresist.

  As the solvent, those generally used as a solvent for photoresist can be used. Specifically, glycols such as 2-methoxyethyl ether, ethylene glycol monomethyl ether (2-methoxyethanol), propylene glycol monomethyl ether and 1-methoxy-2-propanol acetate, and lactate esters such as ethyl lactate and methyl lactate , Propionates such as methyl propionate and ethyl propionate, cellosolve esters such as methyl cellosolve acetate, aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone, cyclohexanone and 2-heptanone Can be mentioned. These can be appropriately selected depending on the solubility of the base material in the solvent, film-forming properties, and the like.

  The ratio of the solid content in the composition is generally 1 to 40% by weight of the total weight of the composition. However, this ratio can be appropriately adjusted according to the type of substrate.

The composition of the present invention is uniformly applied on a substrate such as a silicon wafer or an arbitrary work layer formed on the silicon wafer, for example, by a method such as spin coating, dip coating, or painting. After application, in order to remove the solvent, it is generally heated and dried at, for example, 80 to 160 ° C. until the photoresist coating layer becomes a non-adhesive layer. However, the heating conditions can be appropriately adjusted according to the type of the substrate.
Next, the substrate on which the photoresist coating layer has become tack free is exposed through radiation through a photomask to create or improve the solubility difference between the exposed and unexposed areas of the photoresist coating layer. In order to form a relief image, the film is baked after exposure, and then developed with an alkali developer or the like to form a relief image. By such an operation, an ultrafinely processed pattern is formed on the substrate.

When ultrafine processing using extreme ultraviolet light or an electron beam is performed using the photoresist base material and the composition of the present invention, an isolated line of 100 nm or less, particularly 50 nm or less, line / space (L / S) = 1. / 1, patterns such as holes can be formed with high sensitivity, high contrast, and low line edge roughness.
Thereby, the performance of a semiconductor device such as ULSI can be dramatically improved.

  EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples. In addition, the average diameter of the base material was calculated | required by said method.

Example 1
[Photoresist substrate]
(1) Synthesis of calix- [4] -resorcinalene In a three-necked flask (capacity 500 ml) equipped with a dripping funnel sufficiently substituted with nitrogen gas, a Jim Roth condenser, and a thermometer, under a nitrogen stream, After enclosing resorcinol (33 g, 300 mmol) and acetaldehyde (17 ml, 300 mmol), distilled methanol (300 ml) was added under slightly pressurized nitrogen to prepare a methanol solution. The methanol solution was heated to 75 ° C. with stirring in an oil bath. Next, 75 ml of concentrated hydrochloric acid was gradually added while dropping from a dropping funnel, and then the heating and stirring were continued at 75 ° C. for 2 hours. After the completion of the reaction, the mixture was allowed to cool and allowed to reach room temperature, and then cooled in an ice bath. After standing for 1 hour, white target crude crystals were produced, which were filtered off. This crude crystal is washed twice with pure water (100 ml), purified by recrystallization from a mixed solution of ethanol and water, and dried under reduced pressure, whereby all of R in the above formula (15) are hydrogen atoms. Calix- [4] -resorcinalene (16 g, yield 40.2%) was obtained. The structure of this compound was determined by performing NMR measurement, IR measurement, elemental analysis, and the like. In addition, this compound had an average diameter of 0.88 nm and was in an amorphous state at room temperature.

(2) Synthesis of calix- [4] -resorcinalene derivative Obtained in (1) above into a two-necked flask (capacity: 100 ml) equipped with a fully dried, nitrogen-substituted Jim Roth condenser and thermometer. The resulting calix- [4] -resorcinalene (2.07 g, 3.8 mmol), potassium carbonate (7.32 g, 30 mmol), 18-crown-6 (0.52 g, 0.94 mmol), Replaced with nitrogen. Next, 38 ml of acetone was added to make a solution, tert-butyl bromoacetate (3.51 g, 18 mmol) was added, and the mixture was refluxed with stirring in an oil bath at 75 ° C. for 24 hours under a nitrogen atmosphere. . After the completion of the reaction, the mixture was allowed to cool and allowed to reach room temperature, and then ice water was poured into the reaction solution and stirred for 1 hour to obtain a white precipitate. This was filtered off and dried under reduced pressure to obtain a crude calix- [4] -resorcinalene derivative in which 50% of R in the above formula (15) was a tert-butyloxycarbonylmethyl group and 50% was a hydrogen atom. The product (3.04 g, yield 80%) was obtained. Subsequently, in order to remove a small amount of potassium carbonate, it was dissolved in acetone (10 ml) and poured into an acetic acid aqueous solution (1 mol / liter, 300 ml) to obtain white crystals. This was filtered off and dried under reduced pressure to obtain the purified derivative (2.58 g, purification yield 85%). The structure of this compound was determined by performing TGA (weight of tert-butyloxycarbonylmethyl group eliminated at around 170 ° C.), NMR measurement, IR measurement, elemental analysis and the like. Further, this compound had an average diameter of 1.10 nm and was in an amorphous state at room temperature. Furthermore, the amount of potassium ions contained in this compound was 1,000 to 1,500 ppm as a result of quantitative analysis using an inductively coupled plasma mass spectrometer.

(3) Purification of calix- [4] -resorcinalene derivative The calix- [4] -resorcinalene derivative (2 g) obtained in (2) above was charged into an acetic acid aqueous solution (100 mL) adjusted to 1 mol / L, and Under stirring, the mixture was stirred for 3 hours. This was filtered and washed three times with pure water (100 mL). The washed solid was dried under reduced pressure at 80 ° C. to obtain a derivative treated with an acetic acid aqueous solution.
Next, a cation exchange resin (Amberlyst 15J-HG Dry, manufactured by Organo) substituted with acetone in advance is packed in a glass column, and the acetone solution of the treated derivative is passed therethrough, and the acetone solution is concentrated under reduced pressure. By re-precipitation by putting in pure water and further drying under reduced pressure at 80 ° C., 1.5 g (purification yield: 75%) of the derivative subjected to ion exchange treatment was obtained. This was used as a photoresist base material. The amount of potassium ions contained in this derivative was 0.5 to 1.5 ppm as a result of quantitative analysis using an inductively coupled plasma mass spectrometer.

Example 2
[Photoresist composition]
The solid content consisting of 100 parts by weight of the base material produced and purified in Example 1 and 10 parts by weight of (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene) -2-methylphenylacetonitrile (PAG) Was dissolved in 2-methoxyethanol (solvent) to prepare a photoresist solution (photoresist composition). This photoresist solution was spin-coated (1,000 rpm, 60 seconds) on a silicon wafer and heated at 90 ° C. for 180 seconds to form a film having a thickness of 1.2 μm. Next, the substrate having this coating was irradiated with UV light at 80 mJ / cm ² using a g-ray exposure apparatus (M-1S (trade name) manufactured by Mikasa Co., Ltd.). Thereafter, it was baked at 100 ° C. for 60 seconds and treated with a 0.25N aqueous tetrabutylammonium hydroxide solution. As a result of measuring the dissolution rate from the decrease in the film thickness, it was 1,350 nm / second.

Example 3
[Photoresist composition]
In Example 2, it implemented like Example 2 except the exposure amount of UV light by a g-line exposure apparatus having been 5 mJ / cm < ² >. As a result of measuring the dissolution rate from the decrease in film thickness, it was 120 nm / second.

Comparative Example 1
[Photoresist composition]
100 parts by weight, (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene) -2-methylphenylacetonitrile (PAG) based on the calix- [4] -resorcinalene derivative produced in Example 1 (2) A solid content of 20 parts by weight was dissolved in ethyl lactate (solvent) so that the ratio was 20% by weight to prepare a photoresist solution (photoresist composition). This photoresist solution was spin-coated (1,000 rpm, 60 seconds) on a silicon wafer and heated at 90 ° C. for 180 seconds to form a film having a thickness of 1.2 μm. Next, the substrate having this coating was irradiated with 100 mJ / cm ² of UV light using the g-ray exposure apparatus described above. Thereafter, it was baked at 100 ° C. for 30 seconds and treated with a 0.25N aqueous tetrabutylammonium hydroxide solution. As a result of measuring the dissolution rate from the decrease in film thickness, it was 28 nm / second.

Example 4
[Photoresist composition]
The solid content consisting of 100 parts by weight of the base material produced and purified in Example 1 and 2 parts by weight of (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene) -2-methylphenylacetonitrile (PAG) Was dissolved in 2-methoxyethanol so as to be 20 weight percent to prepare a photoresist solution (photoresist composition). This photoresist solution was spin-coated (1,000 rpm, 60 seconds) on a silicon wafer, and heated at 100 ° C. for 180 seconds to form a film having a thickness of 1.2 μm. Next, the substrate having this coating was irradiated with UV light using the g-ray exposure apparatus described above. Thereafter, it was baked at 110 ° C. for 60 seconds and treated with a 2.38 wt% aqueous tetrabutylammonium hydroxide solution for 60 seconds. A solubility curve was prepared by changing the exposure intensity of UV light. When the sensitivity and contrast of the resist were estimated from these curves, they were 19.2 mJ / cm ² and 5.0, respectively. Further, when UV light was irradiated at 5 mJ / cm ² using a mask, an image having a line width of 6 μm could be obtained.

Example 5
[Photoresist composition]
The same procedure as in Example 1 (2) was conducted except that the ratio of potassium carbonate to tert-butyl bromoacetate was changed to 4/5 in Example 1 (2). 40% of R in the above formula (15) A calix- [4] -resorcinalene derivative (average diameter: 1.06 nm, amorphous state at room temperature) in which is a tert-butyroxycarbonylmethyl group and 60% is a hydrogen atom was synthesized in Example 1 (3) A photoresist solution was prepared in the same manner as in Example 4 using a material purified by the same method as in Example 4, and a sensitivity curve was prepared. As a result, the sensitivity of the resist was estimated from this curve and found to be 10.0 mJ / cm ² .

Example 6
[Photoresist composition]
The same procedure as in Example 1 (2) was performed except that the ratio of potassium carbonate to tert-butyl bromoacetate was 3/5 in Example 1 (2). A calix- [4] -resorcinalene derivative (average diameter: 1.00 nm, amorphous state at room temperature) in which 27% is a tert-butyloxycarbonylmethyl group and 73% is a hydrogen atom was synthesized in Example 1 ( Using a material purified by the same method as 3) as a substrate, a photoresist solution was prepared by the same method as in Example 4, and its sensitivity curve was prepared. As a result, the sensitivity of the resist was estimated from this curve and found to be 2.4 mJ / cm ² .

  The photoresist base material and the composition thereof of the present invention are suitably used in the electric / electronic field and the optical field such as semiconductor devices.

Claims (20)

A photoresist base material comprising an extreme ultraviolet light-reactive organic compound represented by the following general formula (1), wherein the basic impurity content is 10 ppm or less.

[In the formula, A represents an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, or a cyclic structure in which these groups are repeated. A central structure consisting of organic groups of the structure, B, C and D are mutually independent extreme ultraviolet light reactive groups, groups reactive to the action of chromophores active in extreme ultraviolet light, or these An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, and a substituent having a branched structure, , Y and Z are mutually independent single bonds or ether bonds, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D may contain a substituent having a hetero atom. ] The photoresist substrate according to claim 1, wherein the extreme ultraviolet light-reactive organic compound is in an amorphous state at room temperature and has an average molecular diameter of 2 nm or less. A is

An organic group represented by
Wherein B, C and D are groups reactive to extreme ultraviolet light reactive groups, chromophore active to extreme ultraviolet light, or

[Ar is substituted with RO- and / or ROCO- (R, RO- and ROCO- are groups reactive to the action of extreme ultraviolet light reactive groups or chromophores active on extreme ultraviolet light) A phenyl group or a naphthyl group. ]
An organic group represented by
The photoresist substrate according to claim 1, wherein X, Y, and Z are ether bonds. A is

An organic group represented by
B, C and D are a hydrogen atom, a tert-butyl group, a tert-butyloxycarbonylmethyl group, a tert-butyloxycarbonyl group, a 1-tetrahydropyranyl group, a 1-tetrahydrofuranyl group, a 1-ethoxyethyl group, 1-phenoxyethyl group,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
Or an organic group represented by

[Ar is RO- and / or ROCO- (R is hydrogen, tert-butyl group, tert-butyoxycarbonylmethyl group, tert-butyoxycarbonyl group, 1-tetrahydropyranyl group, 1-tetrahydrofuranyl group, 1-ethoxyethyl group, 1-phenoxyethyl group, or

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
A phenyl group or a naphthyl group substituted with an organic group represented by ]
An organic group represented by
The photoresist substrate according to claim 3, wherein X, Y, and Z are ether bonds. A is

An organic group represented by
B, C and D are a hydrogen atom, a tert-butyl group, a tert-butyloxycarbonylmethyl group, a tert-butyloxycarbonyl group, a 1-tetrahydropyranyl group, a 1-tetrahydrofuranyl group, a 1-ethoxyethyl group, 1-phenoxyethyl group, or

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
An organic group represented by
The photoresist base material according to claim 4, wherein X, Y and Z are ether bonds. The photoresist base material which consists of a radiation sensitive organic compound represented by following General formula (1) whose content of a basic impurity is 10 ppm or less.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ] Said

The organic group represented by is 4- (tert-butoxycarbonyloxy) benzyl group or 3,5-di (tert-butoxycarbonyloxy) benzyl group. Photo resist substrate. The photoresist base material according to claim 6 or 7, wherein the radiation is extreme ultraviolet light or an electron beam. The photoresist base material according to claim 1, wherein at least one of the B, C, and D is a hydrogen atom, and the X, Y, and Z are ether bonds. The photoresist composition containing the solid content containing the photoresist base material as described in any one of Claims 1-9, and a solvent. Furthermore, the photoresist composition of Claim 10 containing a photo-acid generator. A method for purifying a photoresist base material, comprising washing a photoresist base material composed of an extreme ultraviolet light-reactive organic compound represented by the following general formula (1) with an acidic aqueous solution and treating with an ion exchange resin.

[In the formula, A represents an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, or a cyclic structure in which these groups are repeated. A central structure consisting of organic groups of the structure, B, C and D are mutually independent extreme ultraviolet light reactive groups, groups reactive to the action of chromophores active in extreme ultraviolet light, or these An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, and a substituent having a branched structure, , Y and Z are mutually independent single bonds or ether bonds, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D may contain a substituent having a hetero atom. ] A method for purifying a photoresist base material, comprising washing a photoresist base material comprising a radiation-sensitive organic compound represented by the following general formula (1) with an acidic aqueous solution and treating with an ion exchange resin.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ] The method for purifying a photoresist substrate according to claim 12 or 13, wherein the acidic aqueous solution is an acetic acid aqueous solution. A method for improving the radiation sensitivity of a photoresist substrate made of an extreme ultraviolet light-reactive organic compound represented by the following general formula (1) by setting the content of basic impurities to 10 ppm or less.

[In the formula, A represents an aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, or a cyclic structure in which these groups are repeated. A central structure consisting of organic groups of the structure, B, C and D are mutually independent extreme ultraviolet light reactive groups, groups reactive to the action of chromophores active in extreme ultraviolet light, or these An aliphatic group having 1 to 50 carbon atoms, an aromatic group having 6 to 50 carbon atoms, an organic group containing the aliphatic group and the aromatic group at the same time, and a substituent having a branched structure, , Y and Z are mutually independent single bonds or ether bonds, l, m and n are mutually independent integers of 0 to 5 satisfying l + m + n ≧ 1, and A, B, C and D may contain a substituent having a hetero atom. ] A method for improving the radiation sensitivity of a photoresist base material comprising a radiation-sensitive organic compound represented by the following general formula (1) by setting the content of basic impurities to 10 ppm or less.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ] A fine processing method by lithography using the photoresist composition according to claim 10. A semiconductor device manufactured using the photoresist composition according to claim 10. An organic compound represented by the following general formula (1), wherein the content of basic impurities is 10 ppm or less.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ] A method for purifying an organic compound, in which an organic compound represented by the following general formula (1) is washed with an acidic aqueous solution and treated with an ion exchange resin.

[Wherein A is

An organic group represented by
B, C and D are mutually independent,

[P is an (r + 1) -valent aromatic group having 6 to 20 carbon atoms, Q is an organic group having 4 to 30 carbon atoms, r is an integer of 1 to 10, and s is 0 It is an integer of -10. ]
In which 1 + m + n = 3 or 8. ]