JP6680292B2 - Polymer, positive resist composition, and method for forming resist pattern - Google Patents
Polymer, positive resist composition, and method for forming resist pattern Download PDFInfo
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- 229920000642 polymer Polymers 0.000 title claims description 137
- 239000000203 mixture Substances 0.000 title claims description 61
- 238000000034 method Methods 0.000 title claims description 31
- AOGQPLXWSUTHQB-UHFFFAOYSA-N hexyl acetate Chemical compound CCCCCCOC(C)=O AOGQPLXWSUTHQB-UHFFFAOYSA-N 0.000 claims description 92
- 239000002904 solvent Substances 0.000 claims description 28
- 238000009826 distribution Methods 0.000 claims description 26
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical group CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 claims description 24
- 239000010408 film Substances 0.000 description 80
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 36
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 34
- 238000000746 purification Methods 0.000 description 24
- 239000012046 mixed solvent Substances 0.000 description 23
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 22
- 239000000178 monomer Substances 0.000 description 21
- 238000004090 dissolution Methods 0.000 description 17
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 17
- 238000006116 polymerization reaction Methods 0.000 description 16
- 239000003505 polymerization initiator Substances 0.000 description 14
- 230000005865 ionizing radiation Effects 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- 238000010894 electron beam technology Methods 0.000 description 10
- 229920001577 copolymer Polymers 0.000 description 9
- 238000011156 evaluation Methods 0.000 description 9
- 238000005259 measurement Methods 0.000 description 9
- 229940072049 amyl acetate Drugs 0.000 description 8
- PGMYKACGEOXYJE-UHFFFAOYSA-N anhydrous amyl acetate Natural products CCCCCOC(C)=O PGMYKACGEOXYJE-UHFFFAOYSA-N 0.000 description 8
- MNWFXJYAOYHMED-UHFFFAOYSA-M heptanoate Chemical compound CCCCCCC([O-])=O MNWFXJYAOYHMED-UHFFFAOYSA-M 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 239000010703 silicon Substances 0.000 description 7
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 6
- 238000005227 gel permeation chromatography Methods 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 5
- RDOXTESZEPMUJZ-UHFFFAOYSA-N anisole Chemical compound COC1=CC=CC=C1 RDOXTESZEPMUJZ-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000003776 cleavage reaction Methods 0.000 description 4
- BGTOWKSIORTVQH-UHFFFAOYSA-N cyclopentanone Chemical compound O=C1CCCC1 BGTOWKSIORTVQH-UHFFFAOYSA-N 0.000 description 4
- 230000018109 developmental process Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 238000001226 reprecipitation Methods 0.000 description 4
- 230000001629 suppression Effects 0.000 description 4
- 125000001309 chloro group Chemical group Cl* 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 230000007017 scission Effects 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- UZKWTJUDCOPSNM-UHFFFAOYSA-N methoxybenzene Substances CCCCOC=C UZKWTJUDCOPSNM-UHFFFAOYSA-N 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- 238000012887 quadratic function Methods 0.000 description 2
- SZTBMYHIYNGYIA-UHFFFAOYSA-N 2-chloroacrylic acid Chemical group OC(=O)C(Cl)=C SZTBMYHIYNGYIA-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 150000001733 carboxylic acid esters Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 238000004440 column chromatography Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 125000004051 hexyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- AWJZTPWDQYFQPQ-UHFFFAOYSA-N methyl 2-chloroprop-2-enoate Chemical group COC(=O)C(Cl)=C AWJZTPWDQYFQPQ-UHFFFAOYSA-N 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000012788 optical film Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000007870 radical polymerization initiator Substances 0.000 description 1
- 230000007261 regionalization Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
- C08F212/02—Monomers containing only one unsaturated aliphatic radical
- C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
- C08F212/06—Hydrocarbons
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/22—Esters containing halogen
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/039—Macromolecular compounds which are photodegradable, e.g. positive electron resists
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/20—Exposure; Apparatus therefor
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- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Medicinal Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Materials For Photolithography (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Description
本発明は、重合体およびポジ型レジスト組成物、並びに、レジストパターン形成方法に関するものである。特には、本発明は、ポジ型レジストとして好適に使用し得る重合体および当該重合体を含むポジ型レジスト組成物、並びに、当該ポジ型レジスト組成物を用いたレジストパターン形成方法に関するものである。 The present invention relates to a polymer and a positive resist composition, and a method for forming a resist pattern. In particular, the present invention relates to a polymer that can be preferably used as a positive resist, a positive resist composition containing the polymer, and a method for forming a resist pattern using the positive resist composition.
従来、半導体製造等の分野において、電子線などの電離放射線や紫外線などの短波長の光（以下、電離放射線と短波長の光とを合わせて「電離放射線等」と称することがある。）の照射により主鎖が切断されて現像液に対する溶解性が増大する重合体が、主鎖切断型のポジ型レジストとして使用されている。 Conventionally, in the field of semiconductor manufacturing and the like, short-wavelength light such as ionizing radiation such as electron beams and ultraviolet rays (hereinafter, ionizing radiation and short-wavelength light may be collectively referred to as “ionizing radiation and the like”). A polymer whose main chain is cleaved by irradiation to increase its solubility in a developing solution is used as a main chain cleaving positive resist.
そして、例えば特許文献１には、高感度な主鎖切断型のポジ型レジストとして、α−メチルスチレン単位とα−クロロアクリル酸メチル単位とを含有するα−メチルスチレン・α−クロロアクリル酸メチル共重合体よりなるポジ型レジストが開示されている。 And, for example, in Patent Document 1, as a highly sensitive main chain cleavage type positive resist, α-methylstyrene / α-chloromethyl acrylate containing α-methylstyrene unit and α-methyl chloroacrylate unit. A positive resist made of a copolymer is disclosed.
なお、α−メチルスチレン・α−クロロアクリル酸メチル共重合体よりなるポジ型レジストを用いて形成したレジスト膜を使用したレジストパターンの形成は、電離放射線等を照射した露光部と、電離放射線等を照射していない未露光部との現像液に対する溶解速度の差を利用して行われる。そして、現像液としては、例えば、酢酸アミルや酢酸ヘキシルなどのアルキル基を有するカルボン酸エステル溶剤が広く用いられている（例えば、特許文献２参照）。 In addition, the formation of a resist pattern using a resist film formed by using a positive resist made of α-methylstyrene / α-methyl chloroacrylate copolymer is performed by exposing a portion exposed to ionizing radiation, etc. It is carried out by utilizing the difference in the dissolution rate with respect to the developing solution from the unexposed area not irradiated with. As the developing solution, for example, a carboxylic acid ester solvent having an alkyl group such as amyl acetate or hexyl acetate is widely used (see, for example, Patent Document 2).
ここで、露光部と未露光部との間の現像液に対する溶解速度の差を利用してレジストパターンを形成する場合、高解像度のレジストパターンを良好に形成するためには、露光部の現像液への溶解性を高めつつ、未露光部の現像液への溶解を抑制することが求められる。 Here, in the case of forming a resist pattern by utilizing the difference in dissolution rate between the exposed portion and the unexposed portion with respect to the developing solution, in order to form a high-resolution resist pattern favorably, It is required to suppress the dissolution of the unexposed portion in the developing solution while increasing the solubility in the developing solution.
しかし、主鎖切断型のポジ型レジストを用いたレジストパターンの形成においては、露光部および未露光部の現像液に対する溶解性は、ポジ型レジストとして用いる重合体の性状と、現像液の種類との影響を受けて変化する。そして、特許文献１，２に記載のα−メチルスチレン・α−クロロアクリル酸メチル共重合体よりなるポジ型レジストと、酢酸アミルまたは酢酸ヘキシルからなる現像液とを組み合わせて用いる従来のレジストパターン形成方法では、十分に高い解像度のレジストパターンを良好に形成することができなかった。 However, in the formation of a resist pattern using a main chain cleavage type positive resist, the solubility of the exposed portion and the unexposed portion in a developing solution depends on the properties of the polymer used as a positive type resist and the type of the developing solution. Change under the influence of. Then, a conventional resist pattern formation using a positive resist made of α-methylstyrene / α-methyl chloroacrylate copolymer described in Patent Documents 1 and 2 and a developer made of amyl acetate or hexyl acetate in combination The method could not successfully form a resist pattern having a sufficiently high resolution.
そのため、α−メチルスチレン・α−クロロアクリル酸メチル共重合体よりなるポジ型レジストを用いたレジストパターンの形成においては、α−メチルスチレン・α−クロロアクリル酸メチル共重合体の性状と、現像液の種類とを適切に組み合わせ、高解像度のレジストパターンを良好に形成し得るようにすることが求められていた。 Therefore, in the formation of a resist pattern using a positive resist made of α-methylstyrene / α-chloromethyl acrylate copolymer, the properties of α-methylstyrene / α-chloromethyl acrylate copolymer and There has been a demand for an appropriate combination with the type of liquid so that a high-resolution resist pattern can be satisfactorily formed.
本発明者は、高解像度のレジストパターンを良好に形成することを目的として、α−メチルスチレン・α−クロロアクリル酸メチル共重合体の性状と、現像液の種類との組み合わせについて鋭意検討を行った。そして、本発明者は、所定の性状を有するα−メチルスチレン・α−クロロアクリル酸メチル共重合体が、現像液として酢酸ヘキシルを用いた際に、露光部の現像液への溶解性の向上と、未露光部の現像液への溶解抑制とを高いレベルで両立し得るポジ型レジストとして良好に使用できることを見出し、本発明を完成させた。 The present inventor, for the purpose of satisfactorily forming a high-resolution resist pattern, has made earnest studies on the combination of the properties of the α-methylstyrene / α-methyl chloroacrylate copolymer and the type of developer. It was The present inventors have found that when an α-methylstyrene / α-methyl chloroacrylate copolymer having predetermined properties uses hexyl acetate as a developing solution, the solubility of the exposed part in the developing solution is improved. The present invention has been completed based on the finding that it can be favorably used as a positive resist capable of achieving a high level of both the suppression of dissolution of an unexposed portion in a developer and a high level.
即ち、この発明は、上記課題を有利に解決することを目的とするものであり、本発明の重合体は、α−メチルスチレン単位と、α−クロロアクリル酸メチル単位とを含有し、分子量が６０００未満の成分の割合が８％以上であり、分子量分布（Ｍｗ／Ｍｎ）が１．２５未満であることを特徴とする。分子量が６０００未満の成分の割合が８％以上であり、且つ、分子量分布（Ｍｗ／Ｍｎ）が１．２５未満のα−メチルスチレン・α−クロロアクリル酸メチル共重合体は、ポジ型レジストとして使用した際に、酢酸ヘキシルを現像液として用いることで、露光部の現像液への溶解性の向上と、未露光部の現像液への溶解抑制とを高いレベルで両立することができる。従って、ポジ型レジストとして良好に使用することができる。
ここで、本発明において、「分子量分布（Ｍｗ／Ｍｎ）」とは、数平均分子量（Ｍｎ）に対する重量平均分子量（Ｍｗ）の比を指す。そして、本発明において、「数平均分子量（Ｍｎ）」および「重量平均分子量（Ｍｗ）」は、ゲル浸透クロマトグラフィーを用いて測定することができる。また、本発明において、「分子量が６０００未満の成分の割合」は、ゲル浸透クロマトグラフィーによって得られるクロマトグラムを使用し、クロマトグラム中のピークの総面積（Ａ）に対するクロマトグラム中の分子量が６０００未満の成分のピークの面積の合計（Ｂ）の割合（＝（Ｂ／Ａ）×１００％）を算出することにより求めることができる。That is, the present invention is intended to advantageously solve the above problems, the polymer of the present invention contains an α-methylstyrene unit and α-methyl chloroacrylate unit, the molecular weight is The ratio of the components less than 6000 is 8% or more, and the molecular weight distribution (Mw / Mn) is less than 1.25. An α-methylstyrene / α-methyl chloroacrylate copolymer having a molecular weight ratio of less than 6000 of 8% or more and a molecular weight distribution (Mw / Mn) of less than 1.25 is used as a positive resist. By using hexyl acetate as a developing solution when used, it is possible to improve the solubility of the exposed area in the developing solution and suppress dissolution of the unexposed area in the developing solution at a high level. Therefore, it can be favorably used as a positive resist.
Here, in the present invention, “molecular weight distribution (Mw / Mn)” refers to the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In the present invention, the "number average molecular weight (Mn)" and "weight average molecular weight (Mw)" can be measured by gel permeation chromatography. In addition, in the present invention, the "ratio of components having a molecular weight of less than 6000" uses a chromatogram obtained by gel permeation chromatography, and the molecular weight in the chromatogram relative to the total area (A) of peaks in the chromatogram is 6000. It can be obtained by calculating the ratio (= (B / A) × 100%) of the total (B) of the peak areas of the components less than.
ここで、本発明の重合体は、分子量が２００００超の成分の割合が４０％以下であることが好ましい。分子量が２００００超の成分の割合が４０％以下であれば、ポジ型レジストとして使用した際に、露光部の酢酸ヘキシルへの溶解性を更に向上させることができるからである。
ここで、本発明において、「分子量が２００００超の成分の割合」は、ゲル浸透クロマトグラフィーによって得られるクロマトグラムを使用し、クロマトグラム中のピークの総面積（Ａ）に対するクロマトグラム中の分子量が２００００超の成分のピークの面積の合計（Ｃ）の割合（＝（Ｃ／Ａ）×１００％）を算出することにより求めることができる。Here, the polymer of the present invention preferably has a ratio of components having a molecular weight of more than 20,000 of 40% or less. This is because if the proportion of the component having a molecular weight of more than 20,000 is 40% or less, the solubility of the exposed portion in hexyl acetate can be further improved when used as a positive resist.
Here, in the present invention, the "ratio of components having a molecular weight of more than 20,000" uses a chromatogram obtained by gel permeation chromatography, and the molecular weight in the chromatogram with respect to the total area (A) of the peaks in the chromatogram is It can be determined by calculating the ratio (= (C / A) × 100%) of the total (C) of the peak areas of the components exceeding 20,000.
そして、本発明の重合体は、重量平均分子量（Ｍｗ）が１５０００以下であることが好ましい。重量平均分子量（Ｍｗ）が１５０００以下であれば、ポジ型レジストとして使用した際に、露光部の酢酸ヘキシルへの溶解性を更に向上させることができるからである。 The polymer of the present invention preferably has a weight average molecular weight (Mw) of 15,000 or less. This is because when the weight average molecular weight (Mw) is 15,000 or less, the solubility of the exposed portion in hexyl acetate can be further improved when used as a positive resist.
また、この発明は、上記課題を有利に解決することを目的とするものであり、本発明のポジ型レジスト組成物は、上述した重合体の何れかと、溶剤とを含むことを特徴とする。上述した重合体をポジ型レジストとして含有すれば、酢酸ヘキシルを現像液として用いることで、露光部の現像液への溶解性の向上と、未露光部の現像液への溶解抑制とを高いレベルで両立させ、高解像度のレジストパターンを良好に形成することができる。 Moreover, this invention aims at solving the said subject advantageously, and the positive resist composition of this invention is characterized by including any of the above-mentioned polymers, and a solvent. When the above-mentioned polymer is contained as a positive resist, by using hexyl acetate as a developing solution, the solubility of the exposed area in the developing solution is improved and the dissolution of the unexposed area in the developing solution is suppressed to a high level. In both cases, a high-resolution resist pattern can be satisfactorily formed.
更に、この発明は、上記課題を有利に解決することを目的とするものであり、本発明のレジストパターン形成方法は、上述したポジ型レジスト組成物を用いてレジスト膜を形成することと、前記レジスト膜を露光することと、前記露光されたレジスト膜を現像することとを含み、前記現像を、酢酸ヘキシルを９０質量％以上含有する現像液を用いて行うことを特徴とする。上述したポジ型レジスト組成物を用いて形成したレジスト膜と、酢酸ヘキシルを９０質量％以上含有する現像液とを組み合わせて用いれば、高解像度のレジストパターンを良好に形成することができる。
なお、本発明において、現像液中の酢酸ヘキシルの濃度は、ガスクロマトグラフィーにより測定することができる。Furthermore, the present invention has an object to advantageously solve the above-mentioned problems, and a method for forming a resist pattern of the present invention comprises forming a resist film using the positive resist composition described above, It is characterized in that it comprises exposing the resist film and developing the exposed resist film, and the developing is carried out using a developing solution containing 90% by mass or more of hexyl acetate. A high-resolution resist pattern can be satisfactorily formed by using a resist film formed using the positive resist composition described above and a developing solution containing hexyl acetate in an amount of 90% by mass or more in combination.
In the present invention, the concentration of hexyl acetate in the developing solution can be measured by gas chromatography.
本発明の重合体によれば、露光部の現像液への溶解性の向上と、未露光部の現像液への溶解抑制とを高いレベルで両立することができるポジ型レジストを提供することができる。
また、本発明のポジ型レジスト組成物によれば、高解像度のレジストパターンを良好に形成することができる。
更に、本発明のレジストパターン形成方法によれば、高解像度のレジストパターンを良好に形成することができる。According to the polymer of the present invention, it is possible to provide a positive resist capable of achieving both high solubility of exposed areas in a developing solution and suppression of dissolution of unexposed areas in a developing solution at a high level. it can.
Further, according to the positive resist composition of the present invention, a high resolution resist pattern can be satisfactorily formed.
Furthermore, according to the resist pattern forming method of the present invention, a high resolution resist pattern can be satisfactorily formed.
以下、本発明の実施形態について詳細に説明する。
ここで、本発明の重合体は、電子線などの電離放射線や紫外線などの短波長の光の照射により主鎖が切断されて低分子量化する、主鎖切断型のポジ型レジストとして良好に使用することができる。また、本発明のポジ型レジスト組成物は、ポジ型レジストとして本発明の重合体を含むものであり、本発明のレジストパターン形成方法を用いてレジストパターンを形成する際に用いることができる。そして、本発明のレジストパターン形成方法は、例えばビルドアップ基板などのプリント基板を製造する際などに好適に用いることができる。Hereinafter, embodiments of the present invention will be described in detail.
Here, the polymer of the present invention, the main chain is cut by irradiation with light having a short wavelength such as ionizing radiation such as an electron beam or ultraviolet rays to have a low molecular weight, which is favorably used as a main chain cleavage type positive resist. can do. The positive resist composition of the present invention contains the polymer of the present invention as a positive resist, and can be used when forming a resist pattern using the resist pattern forming method of the present invention. The resist pattern forming method of the present invention can be preferably used when manufacturing a printed circuit board such as a build-up circuit board.
（重合体）
本発明の重合体は、α−メチルスチレン単位と、α−クロロアクリル酸メチル単位とを含有するα−メチルスチレン・α−クロロアクリル酸メチル共重合体である。また、本発明の重合体は、分子量が６０００未満の成分の割合が８％以上であり、且つ、分子量分布（Ｍｗ／Ｍｎ）が１．２５未満であることを特徴とする。(Polymer)
The polymer of the present invention is an α-methylstyrene / α-chloromethyl acrylate copolymer containing α-methylstyrene units and α-methyl chloroacrylate units. Further, the polymer of the present invention is characterized in that the proportion of components having a molecular weight of less than 6000 is 8% or more and the molecular weight distribution (Mw / Mn) is less than 1.25.
そして、本発明の重合体は、α位にクロロ基（−Ｃｌ）を有するα−クロロアクリル酸メチルに由来する構造単位（α−クロロアクリル酸メチル単位）を含んでいるので、電離放射線等（例えば、電子線、ＫｒＦレーザー、ＡｒＦレーザー、ＥＵＶレーザーなど）が照射されると、主鎖が容易に切断されて低分子量化する。また、本発明の重合体は、分子量が６０００未満の成分の割合が８％以上であり、且つ、分子量分布（Ｍｗ／Ｍｎ）が１．２５未満であるので、レジストパターンの形成において現像液として使用され得る酢酸ヘキシルに対する溶解性が、電離放射線等の照射の前後で大きく異なる。具体的には、本発明の重合体は、電離放射線等が照射されなければ酢酸ヘキシルに対する溶解性は低いが、電離放射線等が照射されると酢酸ヘキシルに対して高い溶解性を示す。従って、本発明の重合体は、主鎖切断型のポジ型レジストとして用いた際に、現像液として酢酸ヘキシルを用いることで、露光部の現像液への溶解性の向上と、未露光部の現像液への溶解抑制とを高いレベルで両立させることができる。従って、ポジ型レジストとして良好に使用することができる。 And since the polymer of the present invention contains a structural unit (α-methyl chloroacrylate unit) derived from α-methyl chloroacrylate having a chloro group (-Cl) at the α-position, ionizing radiation etc. For example, when irradiated with an electron beam, a KrF laser, an ArF laser, an EUV laser, etc.), the main chain is easily cleaved to lower the molecular weight. Further, since the polymer of the present invention has a ratio of components having a molecular weight of less than 6000 of 8% or more and a molecular weight distribution (Mw / Mn) of less than 1.25, it is used as a developer in forming a resist pattern. Solubility in hexyl acetate that can be used greatly differs before and after irradiation with ionizing radiation or the like. Specifically, the polymer of the present invention has low solubility in hexyl acetate unless irradiated with ionizing radiation or the like, but exhibits high solubility in hexyl acetate when irradiated with ionizing radiation or the like. Therefore, when the polymer of the present invention is used as a main chain scission-type positive resist, by using hexyl acetate as a developing solution, the solubility of the exposed area in the developing solution is improved and the unexposed area is improved. It is possible to achieve a high level of both suppression of dissolution in a developing solution. Therefore, it can be favorably used as a positive resist.
＜α−メチルスチレン単位＞
ここで、α−メチルスチレン単位は、α−メチルスチレンに由来する構造単位である。そして、本発明の重合体は、α−メチルスチレン単位を有しているので、ポジ型レジストとして使用した際に、ベンゼン環の保護安定性により優れた耐ドライエッチング性を発揮する。
なお、本発明の重合体は、α−メチルスチレン単位を３０ｍｏｌ％以上７０ｍｏｌ％以下の割合で含有することが好ましい。<Α-methylstyrene unit>
Here, the α-methylstyrene unit is a structural unit derived from α-methylstyrene. Since the polymer of the present invention has an α-methylstyrene unit, it exhibits excellent dry etching resistance due to the protection stability of the benzene ring when used as a positive resist.
The polymer of the present invention preferably contains the α-methylstyrene unit in a proportion of 30 mol% or more and 70 mol% or less.
＜α−クロロアクリル酸メチル単位＞
また、α−クロロアクリル酸メチル単位は、α−クロロアクリル酸メチルに由来する構造単位である。そして、本発明の重合体は、α−クロロアクリル酸メチル単位を有しているので、電離放射線等が照射されると、塩素原子が脱離し、β開裂反応によって主鎖が容易に切断される。従って、本発明の重合体よりなるポジ型レジストは、高い感度を示す。
なお、本発明の重合体は、α−クロロアクリル酸メチル単位を３０ｍｏｌ％以上７０ｍｏｌ％以下の割合で含有することが好ましい。<Methyl α-chloroacrylate unit>
Further, the α-methyl chloroacrylate unit is a structural unit derived from α-methyl chloroacrylate. Since the polymer of the present invention has an α-methyl chloroacrylate unit, when exposed to ionizing radiation or the like, the chlorine atom is eliminated and the main chain is easily cleaved by the β-cleavage reaction. . Therefore, the positive resist comprising the polymer of the present invention exhibits high sensitivity.
The polymer of the present invention preferably contains the α-chloroacrylate unit in a proportion of 30 mol% or more and 70 mol% or less.
＜分子量分布＞
そして、本発明の重合体の分子量分布（Ｍｗ／Ｍｎ）は、１．２５未満であることが必要であり、１．２０以下であることが好ましく、１．１８以下であることが更に好ましい。重合体の分子量分布（Ｍｗ／Ｍｎ）が１．２５以上の場合、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、露光部の現像液への溶解性を十分に向上させることができず、高解像度のレジストパターンを良好に形成することができない。なお、重合体の調製の容易性の観点からは、本発明の重合体の分子量分布（Ｍｗ／Ｍｎ）は、１．１０以上であることが好ましい。<Molecular weight distribution>
Further, the molecular weight distribution (Mw / Mn) of the polymer of the present invention needs to be less than 1.25, preferably 1.20 or less, and more preferably 1.18 or less. When the molecular weight distribution (Mw / Mn) of the polymer is 1.25 or more, the solubility of the exposed portion in the developer is sufficiently improved when the polymer is used as a positive resist in combination with a developer containing hexyl acetate. Therefore, a high-resolution resist pattern cannot be formed well. From the viewpoint of ease of preparation of the polymer, the molecular weight distribution (Mw / Mn) of the polymer of the present invention is preferably 1.10 or more.
［重量平均分子量］
ここで、本発明の重合体の重量平均分子量（Ｍｗ）は、１５０００以下であることが好ましく、１３０００以下であることがより好ましく、９０００以上であることが好ましく、１００００以上であることがより好ましく、１２０００以上であることが更に好ましい。重合体の重量平均分子量（Ｍｗ）が１５０００以下であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、露光部の現像液への溶解性を十分に向上させることができる。また、重合体の重量平均分子量（Ｍｗ）が９０００以上であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、未露光部の現像液への溶解を十分に抑制することができる。[Weight average molecular weight]
Here, the weight average molecular weight (Mw) of the polymer of the present invention is preferably 15,000 or less, more preferably 13,000 or less, preferably 9000 or more, and more preferably 10,000 or more. It is more preferably 12,000 or more. When the weight average molecular weight (Mw) of the polymer is 15,000 or less, the solubility of the exposed part in the developing solution can be sufficiently improved when the polymer is used as a positive resist in combination with the developing solution containing hexyl acetate. it can. Further, when the weight average molecular weight (Mw) of the polymer is 9000 or more, when used as a positive resist in combination with a developing solution containing hexyl acetate, the unexposed portion is sufficiently suppressed from being dissolved in the developing solution. be able to.
［数平均分子量］
また、本発明の重合体の数平均分子量（Ｍｎ）は、１２０００以下であることが好ましく、１１０００以下であることがより好ましく、８０００以上であることが好ましく、９０００以上であることがより好ましく、１００００以上であることが更に好ましい。重合体の数平均分子量（Ｍｎ）が１２０００以下であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、露光部の現像液への溶解性を十分に向上させることができる。また、重合体の数平均分子量（Ｍｎ）が８０００以上であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、未露光部の現像液への溶解を十分に抑制することができる。[Number average molecular weight]
The number average molecular weight (Mn) of the polymer of the present invention is preferably 12,000 or less, more preferably 11,000 or less, preferably 8000 or more, more preferably 9000 or more, It is more preferably 10,000 or more. When the number average molecular weight (Mn) of the polymer is 12,000 or less, the solubility of the exposed part in the developer can be sufficiently improved when the polymer is used as a positive resist in combination with a developer containing hexyl acetate. it can. Further, when the number average molecular weight (Mn) of the polymer is 8000 or more, when it is used as a positive resist in combination with a developing solution containing hexyl acetate, dissolution of an unexposed portion in the developing solution is sufficiently suppressed. be able to.
＜分子量が６０００未満の成分の割合＞
また、本発明の重合体は、分子量が６０００未満の成分の割合が、８％以上であることが必要であり、２５％以下であることが好ましく、２０％以下であることがより好ましく、１０％以下であることが更に好ましい。分子量が６０００未満の成分の割合が８％未満の場合、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、露光部の現像液への溶解性を十分に向上させることができず、高解像度のレジストパターンを良好に形成することができない。一方、分子量が６０００未満の成分の割合が２５％以下であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、未露光部の現像液への溶解を十分に抑制することができる。<Ratio of components having a molecular weight of less than 6000>
Further, in the polymer of the present invention, the ratio of the component having a molecular weight of less than 6000 needs to be 8% or more, preferably 25% or less, more preferably 20% or less, and more preferably 10% or less. % Or less is more preferable. When the proportion of the component having a molecular weight of less than 6000 is less than 8%, the solubility of the exposed part in the developer can be sufficiently improved when used as a positive resist in combination with a developer containing hexyl acetate. Therefore, a high-resolution resist pattern cannot be formed well. On the other hand, when the proportion of the component having a molecular weight of less than 6000 is 25% or less, when it is used as a positive resist in combination with a developer containing hexyl acetate, the unexposed portion is sufficiently suppressed from being dissolved in the developer. be able to.
＜分子量が２００００超の成分の割合＞
更に、本発明の重合体は、分子量が２００００超の成分の割合が、４０％以下であることが好ましく、２０％以下であることがより好ましく、１７％以下であることが更に好ましく、２％以上であることが好ましく、１０％以上であることがより好ましい。分子量が２００００超の成分の割合が４０％以下であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、露光部の現像液への溶解性を十分に向上させ、高解像度のレジストパターンを良好に形成することができる。また、分子量が２００００超の成分の割合が２％以上であれば、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、未露光部の現像液への溶解を十分に抑制することができる。<Ratio of components having a molecular weight of more than 20,000>
Further, in the polymer of the present invention, the proportion of the component having a molecular weight of more than 20,000 is preferably 40% or less, more preferably 20% or less, further preferably 17% or less, and 2%. It is preferably not less than 10%, more preferably not less than 10%. When the proportion of the component having a molecular weight of more than 20,000 is 40% or less, the solubility of the exposed part in the developer is sufficiently improved when used as a positive resist in combination with a developer containing hexyl acetate, and A resist pattern of resolution can be formed well. When the proportion of the component having a molecular weight of more than 20,000 is 2% or more, when it is used as a positive resist in combination with a developer containing hexyl acetate, the unexposed portion is sufficiently suppressed from being dissolved in the developer. be able to.
＜分子量が４００００超の成分の割合＞
また、本発明の重合体は、分子量が４００００超の成分を含有しないことが好ましい。分子量が４００００超の成分を含有しなければ、酢酸ヘキシルを含む現像液と組み合わせてポジ型レジストとして使用した際に、露光部の現像液への溶解性を十分に向上させ、高解像度のレジストパターンを良好に形成することができる。
なお、本発明において、「分子量が４００００超の成分の割合」は、ゲル浸透クロマトグラフィーによって得られるクロマトグラムを使用し、クロマトグラム中のピークの総面積（Ａ）に対するクロマトグラム中の分子量が４００００超の成分のピークの面積の合計（Ｄ）の割合（＝（Ｄ／Ａ）×１００％）を算出することにより求めることができる。<Ratio of components having a molecular weight of over 40,000>
Further, the polymer of the present invention preferably does not contain a component having a molecular weight of more than 40,000. As long as it does not contain a component having a molecular weight of more than 40,000, when it is used as a positive resist in combination with a developer containing hexyl acetate, the solubility of the exposed portion in the developer is sufficiently improved, and a high resolution resist pattern is obtained. Can be satisfactorily formed.
In the present invention, the "ratio of components having a molecular weight of more than 40,000" uses a chromatogram obtained by gel permeation chromatography, and the molecular weight in the chromatogram relative to the total area (A) of peaks in the chromatogram is 40,000. It can be obtained by calculating the ratio (= (D / A) × 100%) of the total (D) of the peak areas of the super component.
（重合体の調製方法）
そして、上述した性状を有する重合体は、例えば、α−メチルスチレンとα−クロロアクリル酸メチルとを含む単量体組成物を重合させた後、得られた重合物を精製することにより調製することができる。
なお、重合体の組成、分子量分布、重量平均分子量および数平均分子量、並びに、重合体中の各分子量の成分の割合は、重合条件および精製条件を変更することにより調整することができる。具体的には、例えば、重量平均分子量および数平均分子量は、重合温度を高くすれば、小さくすることができる。また、重量平均分子量および数平均分子量は、重合時間を短くすれば、小さくすることができる。(Method for preparing polymer)
Then, the polymer having the above-described properties is prepared, for example, by polymerizing a monomer composition containing α-methylstyrene and α-methyl chloroacrylate, and then purifying the obtained polymer. be able to.
The composition of the polymer, the molecular weight distribution, the weight average molecular weight and the number average molecular weight, and the ratio of each molecular weight component in the polymer can be adjusted by changing the polymerization conditions and the purification conditions. Specifically, for example, the weight average molecular weight and the number average molecular weight can be reduced by increasing the polymerization temperature. The weight average molecular weight and the number average molecular weight can be reduced by shortening the polymerization time.
＜単量体組成物の重合＞
ここで、本発明の重合体の調製に用いる単量体組成物としては、α−メチルスチレンおよびα−クロロアクリル酸メチルを含む単量体と、溶媒と、重合開始剤と、任意に添加される添加剤との混合物を用いることができる。そして、単量体組成物の重合は、既知の方法を用いて行うことができる。中でも、溶媒としては、シクロペンタノンなどを用いることが好ましく、重合開始剤としては、アゾビスイソブチロニトリルなどのラジカル重合開始剤を用いることが好ましい。<Polymerization of monomer composition>
Here, as the monomer composition used for the preparation of the polymer of the present invention, a monomer containing α-methylstyrene and α-methyl chloroacrylate, a solvent, a polymerization initiator, and optionally added. Mixtures with other additives can be used. Then, the polymerization of the monomer composition can be performed using a known method. Among them, cyclopentanone or the like is preferably used as the solvent, and radical polymerization initiators such as azobisisobutyronitrile are preferably used as the polymerization initiator.
なお、重合体の組成は、重合に使用した単量体組成物中の各単量体の含有割合を変更することにより調整することができる。また、重合体中に含まれている分子量が高い成分の割合は、重合開始剤の量を変更することにより調整することができ、例えば重合開始剤の量を少なくすれば、分子量が高い成分の割合を増加させることができる。 The composition of the polymer can be adjusted by changing the content ratio of each monomer in the monomer composition used for the polymerization. Further, the ratio of the component having a high molecular weight contained in the polymer can be adjusted by changing the amount of the polymerization initiator. For example, if the amount of the polymerization initiator is reduced, the component having a high molecular weight The rate can be increased.
そして、単量体組成物を重合して得られた重合物は、特に限定されることなく、重合物を含む溶液にテトラヒドロフラン等の良溶媒を添加した後、良溶媒を添加した溶液をメタノール等の貧溶媒中に滴下して重合物を凝固させることにより回収し、以下のようにして精製することができる。 The polymer obtained by polymerizing the monomer composition is not particularly limited, and after adding a good solvent such as tetrahydrofuran to the solution containing the polymer, the solution to which the good solvent is added is methanol or the like. The polymer can be collected by coagulating the polymer by dropping it in the poor solvent, and purified as follows.
＜重合物の精製＞
得られた重合物を精製して上述した性状を有する重合体を得る際に用いる精製方法としては、特に限定されることなく、再沈殿法やカラムクロマトグラフィー法などの既知の精製方法を用いることができる。中でも、精製方法としては、再沈殿法を用いることが好ましい。
なお、重合物の精製は、複数回繰り返して実施してもよい。<Purification of polymer>
The purification method used when purifying the obtained polymer to obtain the polymer having the above-mentioned properties is not particularly limited, and a known purification method such as a reprecipitation method or a column chromatography method may be used. You can Among them, the reprecipitation method is preferably used as the purification method.
The purification of the polymer may be repeated multiple times.
そして、再沈殿法による重合物の精製は、例えば、得られた重合物をテトラヒドロフラン等の良溶媒に溶解した後、得られた溶液を、テトラヒドロフラン等の良溶媒とメタノール等の貧溶媒との混合溶媒に滴下し、重合物の一部を析出させることにより行うことが好ましい。このように、良溶媒と貧溶媒との混合溶媒中に重合物の溶液を滴下して重合物の精製を行えば、良溶媒および貧溶媒の種類や混合比率を変更することにより、得られる重合体の分子量分布、重量平均分子量、数平均分子量および分子量が低い成分の割合を容易に調整することができる。具体的には、例えば、混合溶媒中の良溶媒の割合を高めるほど、混合溶媒中で析出する重合体の分子量を大きくすることができる。 And, the purification of the polymer by the reprecipitation method, for example, after dissolving the obtained polymer in a good solvent such as tetrahydrofuran, the resulting solution is mixed with a good solvent such as tetrahydrofuran and a poor solvent such as methanol. It is preferable to carry out the reaction by dropping it in a solvent and precipitating a part of the polymer. In this way, if the solution of the polymer is added dropwise to the mixed solvent of the good solvent and the poor solvent to purify the polymer, the weight of the polymer obtained by changing the kind and the mixing ratio of the good solvent and the poor solvent can be obtained. The molecular weight distribution, the weight average molecular weight, the number average molecular weight, and the proportion of components having a low molecular weight of the combined product can be easily adjusted. Specifically, for example, the higher the ratio of the good solvent in the mixed solvent, the larger the molecular weight of the polymer precipitated in the mixed solvent.
なお、再沈殿法により重合物を精製する場合、本発明の重合体としては、所望の性状を満たせば、良溶媒と貧溶媒との混合溶媒中で析出した重合体を用いてもよいし、混合溶媒中で析出しなかった重合体（即ち、混合溶媒中に溶解している重合体）を用いてもよい。ここで、混合溶媒中で析出しなかった重合体は、濃縮乾固などの既知の手法を用いて混合溶媒中から回収することができる。 In the case of purifying the polymer by a reprecipitation method, the polymer of the present invention may be a polymer precipitated in a mixed solvent of a good solvent and a poor solvent, if the desired properties are satisfied, A polymer not precipitated in the mixed solvent (that is, a polymer dissolved in the mixed solvent) may be used. Here, the polymer not precipitated in the mixed solvent can be recovered from the mixed solvent by a known method such as concentration to dryness.
（ポジ型レジスト組成物）
本発明のポジ型レジスト組成物は、上述した重合体と、溶剤とを含み、任意に、レジスト組成物に配合され得る既知の添加剤を更に含有する。そして、本発明のポジ型レジスト組成物は、上述した重合体をポジ型レジストとして含有しているので、本発明のポジ型レジスト組成物を塗布および乾燥させて得られるレジスト膜と、酢酸ヘキシルを含む現像液と組み合わせて使用すれば、高解像度のレジストパターンを良好に形成することができる。(Positive resist composition)
The positive resist composition of the present invention contains the above-mentioned polymer and a solvent, and optionally further contains a known additive that can be incorporated into the resist composition. Since the positive resist composition of the present invention contains the above-mentioned polymer as a positive resist, a resist film obtained by coating and drying the positive resist composition of the present invention, and hexyl acetate. A high-resolution resist pattern can be satisfactorily formed by using it in combination with a developing solution containing it.
＜溶剤＞
なお、溶剤としては、上述した重合体を溶解可能な溶剤であれば既知の溶剤を用いることができる。中でも、適度な粘度のポジ型レジスト組成物を得てポジ型レジスト組成物の塗工性を向上させる観点からは、溶剤としてはアニソールを用いることが好ましい。<Solvent>
As the solvent, any known solvent can be used as long as it can dissolve the above-mentioned polymer. Among them, anisole is preferably used as the solvent from the viewpoint of obtaining a positive resist composition having an appropriate viscosity and improving the coatability of the positive resist composition.
（レジストパターン形成方法）
本発明のレジストパターン形成方法は、レジスト膜を形成すること（膜形成工程）と、膜形成工程で形成したレジスト膜を露光すること（露光工程）と、露光工程で露光されたレジスト膜を現像すること（現像工程）とを含む。そして、本発明のレジストパターン形成方法は、膜形成工程において上述したポジ型レジスト組成物を用いてレジスト膜を形成し、現像工程において酢酸ヘキシルを９０質量％以上含有する現像液を用いて現像を行うことを特徴とする。(Method of forming resist pattern)
The resist pattern forming method of the present invention comprises forming a resist film (film forming step), exposing the resist film formed in the film forming step (exposure step), and developing the resist film exposed in the exposure step. Doing (development step). Then, the resist pattern forming method of the present invention forms a resist film using the above-described positive resist composition in the film forming step, and develops it using a developing solution containing 90% by mass or more of hexyl acetate in the developing step. It is characterized by performing.
＜膜形成工程＞
膜形成工程では、例えば基板などのレジストパターンを利用して加工される被加工物の上に上述したポジ型レジスト組成物を塗布し、塗布したポジ型レジスト組成物を乾燥させてレジスト膜を形成する。
ここで、基板としては、特に限定されることなく、プリント基板の製造等に用いられる、絶縁層と、絶縁層上に設けられた銅箔とを有する基板などを用いることができる。また、ポジ型レジスト組成物の塗布方法および乾燥方法としては、特に限定されることなく、レジスト膜の形成に一般的に用いられている方法を用いることができる。<Film formation step>
In the film forming step, for example, the positive resist composition described above is applied onto a workpiece to be processed using a resist pattern such as a substrate, and the applied positive resist composition is dried to form a resist film. To do.
Here, the substrate is not particularly limited, and a substrate having an insulating layer and a copper foil provided on the insulating layer, which is used for manufacturing a printed circuit board or the like, can be used. The method of applying and drying the positive resist composition is not particularly limited, and a method generally used for forming a resist film can be used.
＜露光工程＞
露光工程では、膜形成工程で形成したレジスト膜に対し、電離放射線や光を照射して、所望のパターンを描画する。
なお、電離放射線や光の照射には、電子線描画装置やレーザー描画装置などの既知の描画装置を用いることができる。<Exposure process>
In the exposure step, the resist film formed in the film forming step is irradiated with ionizing radiation or light to draw a desired pattern.
A known drawing device such as an electron beam drawing device or a laser drawing device can be used for irradiation of ionizing radiation or light.
＜現像工程＞
そして、現像工程では、露光工程で露光されたレジスト膜と、酢酸ヘキシルを９０質量％以上含有する現像液とを接触させてレジスト膜を現像し、被加工物上にレジストパターンを形成する。この際、レジスト膜は、上述した重合体よりなるポジ型レジストを含んでいるので、露光部ではレジスト膜が酢酸ヘキシルを含む現像液に良好に溶解する一方で、未露光部ではレジスト膜の現像液への溶解が抑制される。その結果、現像工程では、高解像度のレジストパターンを良好に形成することができる。<Developing process>
Then, in the developing step, the resist film exposed in the exposing step is brought into contact with a developing solution containing 90% by mass or more of hexyl acetate to develop the resist film and form a resist pattern on the workpiece. At this time, since the resist film contains the positive resist made of the above-described polymer, the resist film is well dissolved in the developing solution containing hexyl acetate in the exposed portion, while the resist film is developed in the unexposed portion. Dissolution in the liquid is suppressed. As a result, in the developing step, a high resolution resist pattern can be satisfactorily formed.
ここで、レジスト膜と現像液とを接触させる方法は、特に限定されることなく、現像液中へのレジスト膜の浸漬やレジスト膜への現像液の塗布等の既知の手法を用いることができる。 Here, the method of bringing the resist film into contact with the developing solution is not particularly limited, and a known method such as dipping the resist film in the developing solution or coating the developing solution on the resist film can be used. .
そして、現像工程では、レジスト膜の露光部を現像液に良好に溶解させて高解像度のレジストパターンを良好に形成する観点からは、現像液として、実質的に酢酸ヘキシルのみからなる現像液（換言すれば、製造上不可避的に混入した不純物のみを含む酢酸ヘキシル）を用いることが好ましく、精製処理された酢酸ヘキシルを用いることがより好ましい。 Then, in the developing step, from the viewpoint of satisfactorily dissolving the exposed portion of the resist film in a developing solution to form a high-resolution resist pattern satisfactorily, as the developing solution, a developing solution consisting essentially of hexyl acetate alone (in other words, If so, it is preferable to use hexyl acetate containing only impurities that are unavoidably mixed in the production, and it is more preferable to use purified hexyl acetate.
以下、本発明について実施例に基づき具体的に説明するが、本発明はこれら実施例に限定されるものではない。なお、以下の説明において、量を表す「％」および「部」は、特に断らない限り、質量基準である。
そして、実施例および比較例において、重合体の重量平均分子量、数平均分子量および分子量分布、重合体中の各分子量の成分の割合、並びに、レジスト膜の溶解性は、下記の方法で測定および評価した。Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples. In the following description, “%” and “parts” representing amounts are based on mass unless otherwise specified.
Then, in Examples and Comparative Examples, the weight average molecular weight of the polymer, the number average molecular weight and the molecular weight distribution, the ratio of the components of each molecular weight in the polymer, and the solubility of the resist film is measured and evaluated by the following method. did.
＜重量平均分子量、数平均分子量および分子量分布＞
得られた重合体についてゲル浸透クロマトグラフィーを用いて重量平均分子量（Ｍｗ）および数平均分子量（Ｍｎ）を測定し、分子量分布（Ｍｗ／Ｍｎ）を算出した。
具体的には、ゲル浸透クロマトグラフ（東ソー製、ＨＬＣ−８２２０）を使用し、展開溶媒としてテトラヒドロフランを用いて、重合体の重量平均分子量（Ｍｗ）および数平均分子量（Ｍｎ）を標準ポリスチレン換算値として求めた。そして、分子量分布（Ｍｗ／Ｍｎ）を算出した。
＜重合体中の各分子量の成分の割合＞
ゲル浸透クロマトグラフ（東ソー製、ＨＬＣ−８２２０）を使用し、展開溶媒としてテトラヒドロフランを用いて、重合体のクロマトグラムを得た。そして、得られたクロマトグラムから、ピークの総面積（Ａ）、分子量が６０００未満の成分のピークの面積の合計（Ｂ）、分子量が２００００超の成分のピークの面積の合計（Ｃ）および分子量が４００００超の成分のピークの面積の合計（Ｄ）を求めた。そして、下記式を用いて各分子量の成分の割合を算出した。
分子量が６０００未満の成分の割合（％）＝（Ｂ／Ａ）×１００
分子量が２００００超の成分の割合（％）＝（Ｃ／Ａ）×１００
分子量が４００００超の成分の割合（％）＝（Ｄ／Ａ）×１００
＜レジスト膜の溶解性＞
［未露光のレジスト膜の溶解性］
スピンコーター(ミカサ製、ＭＳ−Ａ１５０)を使用し、ポジ型レジスト組成物を直径４インチのシリコンウェハ上に厚さ５００ｎｍになるように塗布した。そして、塗布したポジ型レジスト組成物を温度１８０℃のホットプレートで３分間加熱して、シリコンウェハ上にレジスト膜を形成した。
そして、酢酸アミルよりなる現像液（日本ゼオン社製、ＺＥＤ−Ｎ５０）と、酢酸ヘキシルよりなる現像液（日本ゼオン社製、ＺＥＤ−Ｎ６０）とのそれぞれについて、レジスト膜を形成したシリコンウェハを温度２３℃の現像液に１分間浸漬し、その後、イソプロピルアルコールでリンスした。その後、未露光残膜率および未露光残膜率差を以下のようにして評価した。
−未露光残膜率−
酢酸アミルよりなる現像液を用いた場合と、酢酸ヘキシルよりなる現像液を用いた場合とのそれぞれについて、未露光残膜率（＝浸漬後のレジスト膜の膜厚／シリコンウェハ上に形成したレジスト膜の膜厚）を求め、以下の基準に従って評価した。未露光残膜率が大きいほど、未露光のレジスト膜の溶解性が低いことを示す。
Ａ：未露光残膜率が０．９８５以上
Ｂ：未露光残膜率が０．９６５以上０．９８５未満
Ｃ：未露光残膜率が０．９６５未満
−未露光残膜率差−
酢酸ヘキシルよりなる現像液を用いた場合の未露光残膜率と、酢酸アミルよりなる現像液を用いた場合の未露光残膜率との差（未露光残膜率差＝未露光残膜率（酢酸ヘキシル）−未露光残膜率（酢酸アミル））を求め、以下の基準に従って評価した。未露光残膜率差と、酢酸ヘキシルよりなる現像液を用いた場合の未露光残膜率との双方が大きいほど、現像液として酢酸ヘキシルを使用した際のレジスト膜の未露光部の溶解抑制効果が高く、酢酸ヘキシルとの組み合わせの有用性が高いことを示す。
Ａ：未露光残膜率差が０．０２５以上
Ｂ：未露光残膜率差が０．０１０以上０．０２５未満
Ｃ：未露光残膜率差が０．０１０未満
［露光したレジスト膜の溶解性］
スピンコーター(ミカサ製、ＭＳ−Ａ１５０)を使用し、ポジ型レジスト組成物を直径４インチのシリコンウェハ上に厚さ５００ｎｍになるように塗布した。そして、塗布したポジ型レジスト組成物を温度１８０℃のホットプレートで３分間加熱して、シリコンウェハ上にレジスト膜を形成した。そして、電子線描画装置（エリオニクス社製、ＥＬＳ−５７００）を用いて、電子線の照射量が互いに異なるパターン（寸法５００μｍ×５００μｍ）をレジスト膜上に複数描画し、レジスト用現像液として酢酸ヘキシルよりなる現像液（日本ゼオン社製、ＺＥＤ−Ｎ６０）を用いて温度２３℃で１分間の現像処理を行った後、イソプロピルアルコールで１０秒間リンスした。なお、電子線の照射量は、４μＣから１５２μＣの範囲内で４μＣずつ異ならせた。次に、描画した部分のレジスト膜の厚みを光学式膜厚計（大日本スクリーン製、ラムダエース）で測定し、電子線の総照射量の常用対数と、現像後のレジスト膜の残膜率（＝現像後のレジスト膜の膜厚／シリコンウェハ上に形成したレジスト膜の膜厚）との関係を示す感度曲線を作成した。そして、得られた感度曲線（横軸：電子線の総照射量の常用対数、縦軸：レジスト膜の残膜率（０≦残膜率≦１．００））の残膜率０.２０〜０.８０の範囲において感度曲線を二次関数にフィッティングし、得られた二次関数（残膜率と総照射量の常用対数との関数）上の残膜率０の点と残膜率０.５０の点とを結ぶ直線（感度曲線の傾きの近似線）を作成した。次いで、得られた直線の残膜率が０となる際の、電子線の総照射量Ｅ０（μＣ／ｃｍ２）を求めた。そして、以下の基準に従って評価した。Ｅ０の値が小さいほど、露光部が現像液に溶解し易いことを示す。
Ａ：Ｅ０が５５μＣ／ｃｍ２未満
Ｂ：Ｅ０が５５μＣ／ｃｍ２以上６５μＣ／ｃｍ２未満
Ｃ：Ｅ０が６５μＣ／ｃｍ２以上７５μＣ／ｃｍ２未満
Ｄ：Ｅ０が７５μＣ／ｃｍ２以上<Weight average molecular weight, number average molecular weight and molecular weight distribution>
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the obtained polymer were measured by gel permeation chromatography, and the molecular weight distribution (Mw / Mn) was calculated.
Specifically, using a gel permeation chromatograph (HLC-8220 manufactured by Tosoh Corporation) and using tetrahydrofuran as a developing solvent, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer are converted into standard polystyrene equivalent values. Sought as. Then, the molecular weight distribution (Mw / Mn) was calculated.
<Ratio of each molecular weight component in the polymer>
A gel permeation chromatograph (HLC-8220 manufactured by Tosoh Corporation) was used, and tetrahydrofuran was used as a developing solvent to obtain a chromatogram of the polymer. Then, from the obtained chromatogram, the total area of the peaks (A), the total area of the peaks of the components having a molecular weight of less than 6000 (B), the total area of the peaks of the components of a molecular weight of more than 20,000 (C), and the molecular weight The total area (D) of the peaks of the components having a value of over 40,000 was determined. Then, the ratio of each molecular weight component was calculated using the following formula.
Ratio (%) of components having a molecular weight of less than 6000 = (B / A) × 100
Ratio (%) of components having a molecular weight of more than 20,000 = (C / A) × 100
Ratio (%) of components having a molecular weight of over 40,000 = (D / A) × 100
<Solubility of resist film>
[Solubility of unexposed resist film]
Using a spin coater (MS-A150, manufactured by Mikasa), the positive resist composition was applied on a silicon wafer having a diameter of 4 inches so as to have a thickness of 500 nm. Then, the applied positive resist composition was heated on a hot plate at a temperature of 180 ° C. for 3 minutes to form a resist film on the silicon wafer.
The temperature of the silicon wafer on which the resist film was formed was changed with respect to each of the developer containing amyl acetate (ZED-N50 manufactured by Zeon Corporation) and the developer containing hexyl acetate (ZED-N60 manufactured by Zeon Corporation). It was immersed in a developer at 23 ° C. for 1 minute, and then rinsed with isopropyl alcohol. Then, the unexposed residual film rate and the difference of the unexposed residual film rate were evaluated as follows.
-Unexposed residual film rate-
Unexposed residual film ratio (= film thickness of resist film after dipping / resist formed on silicon wafer) with and without a developer containing amyl acetate and a developer containing hexyl acetate. The film thickness) was obtained and evaluated according to the following criteria. The higher the unexposed residual film rate, the lower the solubility of the unexposed resist film.
A: Unexposed residual film ratio is 0.985 or more B: Unexposed residual film ratio is 0.965 or more and less than 0.985 C: Unexposed residual film ratio is less than 0.965-Unexposed residual film ratio difference-
The difference between the unexposed residual film rate when a developing solution containing hexyl acetate was used and the unexposed residual film rate when using a developing solution containing amyl acetate (unexposed residual film rate difference = unexposed residual film rate) (Hexyl acetate) -remaining unexposed film thickness (amyl acetate)) was determined and evaluated according to the following criteria. The larger the difference between the unexposed residual film rate and the unexposed residual film rate when a developer containing hexyl acetate is used, the more suppressed the dissolution of the unexposed portion of the resist film when hexyl acetate is used as the developer. It shows that the effect is high and the usefulness of the combination with hexyl acetate is high.
A: Unexposed residual film rate difference of 0.025 or more B: Unexposed residual film rate difference of 0.010 or more and less than 0.025 C: Unexposed residual film rate difference of less than 0.010 [dissolution of exposed resist film] sex]
Using a spin coater (MS-A150, manufactured by Mikasa), the positive resist composition was applied on a silicon wafer having a diameter of 4 inches so as to have a thickness of 500 nm. Then, the applied positive resist composition was heated on a hot plate at a temperature of 180 ° C. for 3 minutes to form a resist film on the silicon wafer. Then, a plurality of patterns (dimensions 500 μm × 500 μm) having different electron beam irradiation doses are drawn on the resist film by using an electron beam drawing device (ELS-5700 manufactured by Elionix Co., Ltd.), and hexyl acetate is used as a resist developing solution. A developing solution (ZED-N60, manufactured by Nippon Zeon Co., Ltd.) was used for development for 1 minute at a temperature of 23 ° C., and then rinsed with isopropyl alcohol for 10 seconds. The electron beam irradiation amount was varied by 4 μC in the range of 4 μC to 152 μC. Next, the thickness of the resist film in the drawn part was measured with an optical film thickness meter (Dainippon Screen, Lambda Ace), and the common logarithm of the total electron beam irradiation and the residual film ratio of the resist film after development were measured. A sensitivity curve showing a relationship with (= thickness of resist film after development / thickness of resist film formed on silicon wafer) was prepared. Then, the remaining film ratio of the obtained sensitivity curve (horizontal axis: common logarithm of total irradiation amount of electron beam, vertical axis: residual film ratio of resist film (0 ≦ remaining film ratio ≦ 1.00)) is from 0.20 to The sensitivity curve was fitted to a quadratic function in the range of 0.80, and a point at which the residual film ratio was 0 and a residual film ratio of 0 on the obtained quadratic function (function of residual film ratio and common logarithm of total irradiation) A straight line (an approximate line of the slope of the sensitivity curve) connecting with the point of .50 was created. Next, the total irradiation dose E 0 (μC / cm 2 ) of the electron beam when the residual film ratio of the obtained straight line becomes 0 was obtained. And it evaluated according to the following criteria. The smaller the value of E 0, the easier the exposed area is to dissolve in the developing solution.
A: E 0 is less than 55 μC / cm 2 B: E 0 is 55 μC / cm 2 or more and less than 65 μC / cm 2 C: E 0 is 65 μC / cm 2 or more and less than 75 μC / cm 2 D: E 0 is 75 μC / cm 2 or more
（実施例１）
＜重合体の調製＞
［単量体組成物の重合］
単量体としてのα−クロロアクリル酸メチル３．０ｇおよびα−メチルスチレン６．８８ｇと、溶媒としてのシクロペンタノン２．４７ｇと、重合開始剤としてのアゾビスイソブチロニトリル０．３２７３１ｇとを含む単量体組成物をガラス容器に入れ、ガラス容器を密閉および窒素置換して、窒素雰囲気下、７８℃の恒温槽内で６．５時間撹拌した。その後、室温に戻し、ガラス容器内を大気解放した後、得られた溶液にテトラヒドロフラン（ＴＨＦ）３０ｇを加えた。そして、ＴＨＦを加えた溶液をメタノール３００ｇ中に滴下し、重合物を析出させた。その後、析出した重合物を含む溶液をキリヤマ漏斗によりろ過し、白色の凝固物（重合物）を得た。得られた重合物の重量平均分子量（Ｍｗ）は８２００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４８であった。また、得られた重合物は、α−メチルスチレン単位とα−クロロアクリル酸メチル単位とを５０ｍｏｌ％ずつ含んでいた。
［重合物の精製］
次いで、得られた重合物を１００ｇのＴＨＦに溶解させ、得られた溶液をＴＨＦ４５０ｇとメタノール（ＭｅＯＨ）５５０ｇとの混合溶媒に滴下し、白色の凝固物（α−メチルスチレン単位およびα−クロロアクリル酸メチル単位を含有する重合体）を析出させた。その後、析出した重合体を含む溶液をキリヤマ漏斗によりろ過し、白色の重合体を得た。そして、得られた重合体について、重量平均分子量、数平均分子量および分子量分布、重合体中の各分子量の成分の割合を測定した。結果を表１に示す。
＜ポジ型レジスト組成物の調製＞
得られた重合体を溶剤としてのアニソールに溶解させ、重合体の濃度が１１質量％であるレジスト溶液（ポジ型レジスト組成物）を調製した。そして、レジスト膜の溶解性を評価した。結果を表１に示す。(Example 1)
<Preparation of polymer>
[Polymerization of monomer composition]
3.0 g of α-methyl chloroacrylate and 6.88 g of α-methyl styrene as monomers, 2.47 g of cyclopentanone as a solvent, and 0.32731 g of azobisisobutyronitrile as a polymerization initiator. The monomer composition containing the above was placed in a glass container, the glass container was closed and the atmosphere was replaced with nitrogen, and the mixture was stirred in a constant temperature bath at 78 ° C. for 6.5 hours under a nitrogen atmosphere. Then, the temperature was returned to room temperature, the inside of the glass container was opened to the atmosphere, and 30 g of tetrahydrofuran (THF) was added to the obtained solution. Then, the solution containing THF was dropped into 300 g of methanol to precipitate a polymer. Then, the solution containing the precipitated polymer was filtered through a Kiriyama funnel to obtain a white coagulated product (polymer). The weight average molecular weight (Mw) of the obtained polymer was 8200, and the molecular weight distribution (Mw / Mn) was 1.48. Further, the obtained polymer contained 50 mol% each of α-methylstyrene unit and α-methyl chloroacrylate unit.
[Purification of polymer]
Next, the obtained polymer was dissolved in 100 g of THF, the obtained solution was added dropwise to a mixed solvent of 450 g of THF and 550 g of methanol (MeOH), and a white coagulated product (α-methylstyrene unit and α-chloroacryl unit) was added. A polymer containing methyl acid units) was deposited. Then, the solution containing the precipitated polymer was filtered through a Kiriyama funnel to obtain a white polymer. And about the obtained polymer, the weight average molecular weight, the number average molecular weight, and the molecular weight distribution, and the ratio of the component of each molecular weight in the polymer were measured. The results are shown in Table 1.
<Preparation of positive resist composition>
The obtained polymer was dissolved in anisole as a solvent to prepare a resist solution (positive resist composition) having a polymer concentration of 11% by mass. Then, the solubility of the resist film was evaluated. The results are shown in Table 1.
（実施例２）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．４３６４１ｇに変更した以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は６７００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４８であった。(Example 2)
Polymer, polymer and positive resist composition were prepared in the same manner as in Example 1 except that the amount of azobisisobutyronitrile used as a polymerization initiator during polymerization of the monomer composition was changed to 0.43641 g. The thing was prepared. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The weight average molecular weight (Mw) of the polymer before purification was 6700, and the molecular weight distribution (Mw / Mn) was 1.48.
（実施例３）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．５４５５２ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ４００ｇとＭｅＯＨ６００ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は５９００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４７であった。(Example 3)
The amount of azobisisobutyronitrile as a polymerization initiator used during the polymerization of the monomer composition was changed to 0.54552 g, and a mixed solvent of 400 g of THF and 600 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The weight average molecular weight (Mw) of the polymer before purification was 5900, and the molecular weight distribution (Mw / Mn) was 1.47.
（比較例１）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．０１０９１ｇに変更し、重合物の精製を実施することなく、単量体組成物を重合した際にろ過により回収した重合物をそのまま重合体として用いてポジ型レジスト組成物を調製した以外は実施例１と同様にして、重合物（α−メチルスチレン単位およびα−クロロアクリル酸メチル単位を含有する重合体）およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。(Comparative Example 1)
When the amount of azobisisobutyronitrile as a polymerization initiator used during the polymerization of the monomer composition was changed to 0.01091 g and the monomer composition was polymerized without carrying out purification of the polymer. The polymer (containing α-methylstyrene unit and α-methyl chloroacrylate unit) was prepared in the same manner as in Example 1 except that the positive resist composition was prepared by directly using the polymer recovered by filtration as the polymer. Polymer) and a positive resist composition were prepared. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
（比較例２）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．０３２７３ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ５５０ｇとＭｅＯＨ４５０ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は２９０００であり、分子量分布（Ｍｗ／Ｍｎ）は１．５６であった。(Comparative example 2)
The amount of azobisisobutyronitrile as a polymerization initiator used during the polymerization of the monomer composition was changed to 0.03273 g, and a mixed solvent of 550 g of THF and 450 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The weight average molecular weight (Mw) of the polymer before purification was 29000, and the molecular weight distribution (Mw / Mn) was 1.56.
（比較例３）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．０４３６４ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ５５０ｇとＭｅＯＨ４５０ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は２４０００であり、分子量分布（Ｍｗ／Ｍｎ）は１．５３であった。(Comparative Example 3)
The amount of azobisisobutyronitrile as a polymerization initiator used during the polymerization of the monomer composition was changed to 0.04364 g, and a mixed solvent of 550 g of THF and 450 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The weight average molecular weight (Mw) of the polymer before purification was 24000, and the molecular weight distribution (Mw / Mn) was 1.53.
（比較例４）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．０６５４６ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ５５０ｇとＭｅＯＨ４５０ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は２００００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４８であった。(Comparative example 4)
The amount of azobisisobutyronitrile used as a polymerization initiator during the polymerization of the monomer composition was changed to 0.06546 g, and a mixed solvent of 550 g of THF and 450 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The weight average molecular weight (Mw) of the polymer before purification was 20,000, and the molecular weight distribution (Mw / Mn) was 1.48.
（比較例５）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．０８７２８ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ５００ｇとＭｅＯＨ５００ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は１７０００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４６であった。(Comparative example 5)
The amount of azobisisobutyronitrile as a polymerization initiator used during the polymerization of the monomer composition was changed to 0.08728 g, and a mixed solvent of 500 g of THF and 500 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The polymer before purification had a weight average molecular weight (Mw) of 17,000 and a molecular weight distribution (Mw / Mn) of 1.46.
（比較例６）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．１０９１０ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ５００ｇとＭｅＯＨ５００ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は１５０００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４２であった。(Comparative example 6)
The amount of azobisisobutyronitrile used as a polymerization initiator during the polymerization of the monomer composition was changed to 0.10910 g, and a mixed solvent of 500 g of THF and 500 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The polymer before purification had a weight average molecular weight (Mw) of 15,000 and a molecular weight distribution (Mw / Mn) of 1.42.
（比較例７）
単量体組成物の重合時に使用する重合開始剤としてのアゾビスイソブチロニトリルの量を０．２１８２１ｇに変更し、重合物の精製時に混合溶媒としてＴＨＦ５００ｇとＭｅＯＨ５００ｇとの混合溶媒を用いた以外は実施例１と同様にして、重合物、重合体およびポジ型レジスト組成物を調製した。そして、実施例１と同様にして測定および評価を行った。結果を表１に示す。
なお、精製前の重合物の重量平均分子量（Ｍｗ）は１００００であり、分子量分布（Ｍｗ／Ｍｎ）は１．４７であった。(Comparative Example 7)
The amount of azobisisobutyronitrile as a polymerization initiator used during the polymerization of the monomer composition was changed to 0.21821 g, and a mixed solvent of 500 g of THF and 500 g of MeOH was used as a mixed solvent during the purification of the polymer. A polymer, a polymer and a positive resist composition were prepared in the same manner as in Example 1. Then, measurement and evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.
The polymer before purification had a weight average molecular weight (Mw) of 10,000 and a molecular weight distribution (Mw / Mn) of 1.47.
表１より、実施例１〜３のレジスト膜では、酢酸アミルを現像液として用いた場合には未露光部の溶解を抑制することができないが、酢酸ヘキシルを用いることで未露光部の溶解を十分に抑制し得ることが分かる。即ち、実施例１〜３のレジスト膜は、酢酸アミルと酢酸ヘキシルの何れを現像液として用いても未露光部の溶解を抑制することができる比較例１〜７のレジスト膜と比較し、酢酸ヘキシルとの組み合わせが特に有用であることが分かる。
また、実施例１〜３のレジスト膜、特に実施例１〜２のレジスト膜では、未露光部の酢酸ヘキシルへの溶解を十分に抑制し得る一方で、露光部を酢酸ヘキシルに良好に溶解させることができるので、酢酸ヘキシルを現像液として用いることで高解像度のレジストパターンを良好に形成し得ることが分かる。一方、表１より、比較例１〜７のレジスト膜では、酢酸ヘキシルを現像液として用いると、露光部の現像液に対する溶解性が低下してしまうことが分かる。From Table 1, in the resist films of Examples 1 to 3, when amyl acetate is used as the developing solution, dissolution of the unexposed area cannot be suppressed, but by using hexyl acetate, dissolution of the unexposed area can be suppressed. It turns out that it can be suppressed sufficiently. That is, the resist films of Examples 1 to 3 were compared with the resist films of Comparative Examples 1 to 7 capable of suppressing dissolution of the unexposed portion by using either amyl acetate or hexyl acetate as a developing solution. The combination with hexyl proves to be particularly useful.
Further, in the resist films of Examples 1 to 3, particularly the resist films of Examples 1 and 2, dissolution of unexposed areas in hexyl acetate can be sufficiently suppressed, while exposed areas are satisfactorily dissolved in hexyl acetate. Therefore, it can be seen that a high-resolution resist pattern can be satisfactorily formed by using hexyl acetate as a developing solution. On the other hand, it can be seen from Table 1 that in the resist films of Comparative Examples 1 to 7, when hexyl acetate is used as the developing solution, the solubility of the exposed area in the developing solution decreases.
本発明の重合体によれば、露光部の現像液への溶解性の向上と、未露光部の現像液への溶解抑制とを高いレベルで両立することができるポジ型レジストを提供することができる。
また、本発明のポジ型レジスト組成物によれば、高解像度のレジストパターンを良好に形成することができる。
更に、本発明のレジストパターン形成方法によれば、高解像度のレジストパターンを良好に形成することができる。According to the polymer of the present invention, it is possible to provide a positive resist capable of achieving both high solubility of exposed areas in a developing solution and suppression of dissolution of unexposed areas in a developing solution at a high level. it can.
Further, according to the positive resist composition of the present invention, a high resolution resist pattern can be satisfactorily formed.
Furthermore, according to the resist pattern forming method of the present invention, a high resolution resist pattern can be satisfactorily formed.
Claims (5)
重量平均分子量（Ｍｗ）が１００００以上１５０００以下であり、
分子量が６０００未満の成分の割合が８％以上であり、
分子量が２００００超の成分の割合が２％以上であり、
分子量分布（Ｍｗ／Ｍｎ）が１．２５未満である、重合体。 Containing α-methylstyrene unit and α-methyl chloroacrylate unit,
The weight average molecular weight (Mw) is 10,000 or more and 15,000 or less,
The proportion of components having a molecular weight of less than 6000 is 8% or more,
The proportion of components having a molecular weight of more than 20,000 is 2% or more,
A polymer having a molecular weight distribution (Mw / Mn) of less than 1.25.
前記レジスト膜を露光することと、
前記露光されたレジスト膜を現像することと、
を含み、
前記現像を、酢酸ヘキシルを９０質量％以上含有する現像液を用いて行う、レジストパターン形成方法。 Forming a resist film using the positive resist composition according to claim 4;
Exposing the resist film,
Developing the exposed resist film,
Including,
A method for forming a resist pattern, wherein the development is performed using a developing solution containing 90% by mass or more of hexyl acetate.
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Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |