JP5557022B2 - Method for evaluating a copolymer for lithography - Google Patents
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Description
本発明はリソグラフィー用共重合体の評価方法に関する。 The present invention relates to a method for evaluating a copolymer for lithography.
半導体素子、液晶素子等の製造工程においては、近年、リソグラフィーによるパターン形成の微細化が急速に進んでいる。微細化の手法としては、照射光の短波長化がある。
最近では、KrFエキシマレーザー(波長:248nm)リソグラフィー技術が導入され、さらなる短波長化を図ったArFエキシマレーザー(波長:193nm)リソグラフィー技術及びEUVエキシマレーザー(波長:13nm)リソグラフィー技術が研究されている。
また、例えば、照射光の短波長化およびパターンの微細化に好適に対応できるレジスト組成物として、酸の作用により酸脱離性基が脱離してアルカリ可溶性となる重合体と、光酸発生剤とを含有する、いわゆる化学増幅型レジスト組成物が提唱され、その開発および改良が進められている。
In the manufacturing process of semiconductor elements, liquid crystal elements, etc., in recent years, pattern formation by lithography has been rapidly miniaturized. As a technique for miniaturization, there is a reduction in wavelength of irradiation light.
Recently, KrF excimer laser (wavelength: 248 nm) lithography technology has been introduced, and ArF excimer laser (wavelength: 193 nm) lithography technology and EUV excimer laser (wavelength: 13 nm) lithography technology for further shortening the wavelength have been studied. .
Further, for example, as a resist composition that can suitably cope with a shorter wavelength of irradiation light and a finer pattern, a polymer in which an acid-eliminable group is eliminated by the action of an acid and becomes alkali-soluble, and a photoacid generator A so-called chemically amplified resist composition containing the above has been proposed, and its development and improvement are underway.
ArFエキシマレーザーリソグラフィーにおいて用いられる化学増幅型レジスト用重合体としては、波長193nmの光に対して透明なアクリル系重合体が注目されている。
例えば下記特許文献1には、単量体として、(A)ラクトン環を有する脂環式炭化水素基がエステル結合している(メタ)アクリル酸エステル、(B)酸の作用により脱離可能な基がエステル結合している(メタ)アクリル酸エステル、および(C)極性の置換基を有する炭化水素基または酸素原子含有複素環基がエステル結合している(メタ)アクリル酸エステルを用いてなるレジスト用の共重合体が記載されている。
As a chemically amplified resist polymer used in ArF excimer laser lithography, an acrylic polymer that is transparent to light having a wavelength of 193 nm has attracted attention.
For example, in the following Patent Document 1, (A) (meth) acrylic acid ester in which an alicyclic hydrocarbon group having a lactone ring is ester-bonded and (B) an acid can be eliminated as a monomer. (Meth) acrylic acid ester having an ester bond, and (C) a (meth) acrylic acid ester having a polar substituent and a hydrocarbon group or oxygen atom-containing heterocyclic group bonded to each other. Copolymers for resist are described.
ところで、レジスト用の共重合体は、これを含有するレジスト組成物を使用して良好なパターンを形成できるかどうかが重要である。かかるレジスト用共重合体の評価は、実際にレジスト組成物を調製して、該レジスト組成物の各種現像特性等を測定する方法が一般的である。
また下記特許文献2、3には、レジスト用共重合体を含む樹脂をレジスト溶剤に溶解させ、該溶液についての動的光散乱を測定して得られる特定のパラメータから、該樹脂を用いたレジスト組成物における現像欠陥の発生度合い、パターン寸法のばらつき(LER)の度合い、または液中異物発生の度合いを予測する方法が記載されている。
By the way, it is important for the copolymer for resists to be able to form a favorable pattern using the resist composition containing this. Such a copolymer for resist is generally evaluated by a method of actually preparing a resist composition and measuring various development characteristics of the resist composition.
In Patent Documents 2 and 3 below, a resist using the resin is obtained from specific parameters obtained by dissolving a resin containing a resist copolymer in a resist solvent and measuring dynamic light scattering of the solution. A method for predicting the degree of occurrence of development defects, the degree of variation in pattern dimension (LER), or the degree of occurrence of foreign matter in the liquid is described.
特許文献2、3のように、実際にレジスト組成物を調製して現像を行わなくても、レジスト用共重合体の、レジスト組成物としたときの性能を評価できる方法は、簡便であるうえ、共重合体以外の成分の影響を排除できるため、共重合体自身の性能を厳密に評価する方法として有用である。
しかしながら、次世代レジスト用共重合体の分子量分布・組成分布は、精密に制御されているところ、かかる方法により得られる僅かな構造の差異や現像特性の差異を有する共重合体同士を評価する場合は、上記特許文献に記載の方法では検出精度に問題があり、各共重合体の差異を検出することができない。よって、次世代に求められる微細パターンに対応した寸法の均一性や現像欠陥の発生頻度を反映する評価方法となっていないのが現状である。
As in Patent Documents 2 and 3, a method for evaluating the performance of a resist copolymer as a resist composition without actually preparing and developing a resist composition is simple. Since the influence of components other than the copolymer can be eliminated, it is useful as a method for strictly evaluating the performance of the copolymer itself.
However, the molecular weight distribution and composition distribution of next-generation resist copolymers are precisely controlled. When evaluating copolymers with slight structural differences and development characteristics obtained by such methods. However, in the method described in the above-mentioned patent document, there is a problem in detection accuracy, and a difference between the copolymers cannot be detected. Therefore, the present situation is that the evaluation method does not reflect the uniformity of dimensions corresponding to the fine pattern required for the next generation and the occurrence frequency of development defects.
また、レジスト用共重合体以外のリソグラフィー用共重合体、例えばリソグラフィー工程において、レジスト膜の上層若しくは下層に形成される反射防止膜、ギャップフィル膜、トップコート膜等の薄膜形成に用いられる共重合体についても同様に、これを含有するリソグラフィー用組成物が、高精度の微細加工を行うための性能(リソグラフィー特性)を備えているかどうかが重要である。そして、実際にリソグラフィー用組成物を調製してリソグラフィー工程を行わなくても、リソグラフィー用共重合体の、リソグラフィー用組成物としたときの性能を評価できる方法が望まれている。 In addition, a copolymer for lithography other than the copolymer for resist, for example, a copolymer used for forming a thin film such as an antireflection film, a gap fill film, a top coat film or the like formed on an upper layer or a lower layer of a resist film in a lithography process. Similarly, for the coalescence, it is important whether or not the lithographic composition containing it has the performance (lithographic properties) for performing high-precision fine processing. And the method which can evaluate the performance when it is set as the composition for lithography of the copolymer for lithography without actually preparing the composition for lithography and performing a lithography process is desired.
本発明は前記事情に鑑みてなされたもので、リソグラフィー用共重合体の、リソグラフィー用組成物としたときのリソグラフィー特性を、実際にリソグラフィー用組成物を調製しなくても評価でき、且つ、樹脂としての解像性や溶解性能の均一性を厳格に評価できる方法を提供することを目的とする。 The present invention has been made in view of the above circumstances, and it is possible to evaluate the lithography characteristics of a lithographic copolymer as a lithographic composition without actually preparing the lithographic composition, and a resin. It is an object of the present invention to provide a method capable of strictly evaluating the resolution and uniformity of dissolution performance.
前記課題を解決するために、本発明の第1の態様は、下記工程を含むリソグラフィー用共重合体の評価方法である。
(1)リソグラフィー用共重合体を溶媒に溶解させて試験溶液を調製する工程;
(2)動的光散乱法を用いて、前記試験溶液の粒径分布における散乱強度を測定する工程;
(3)前記試験溶液に貧溶媒を添加し、動的光散乱法を用いて、前記貧溶媒添加後の試験溶液の粒径分布における散乱強度を測定する工程;
(4)前記(2)工程において測定される、粒径分布の任意のピーク(a)の散乱強度を基準とした場合に、貧溶媒の添加により、前記(3)工程において測定される、前記ピーク(a)の散乱強度が、前記基準に対して所定の強度に減少するまでに要する貧溶媒添加量を求める工程;
(5)前記貧溶媒添加量の差異により、前記リソグラフィー用共重合体を含む組成物のリソグラフィー特性を評価する工程。
In order to solve the above problems, a first aspect of the present invention is a method for evaluating a copolymer for lithography, which includes the following steps.
(1) a step of preparing a test solution by dissolving a copolymer for lithography in a solvent;
(2) a step of measuring the scattering intensity in the particle size distribution of the test solution using a dynamic light scattering method;
(3) adding a poor solvent to the test solution and measuring a scattering intensity in a particle size distribution of the test solution after the poor solvent is added using a dynamic light scattering method;
(4) When the scattering intensity of an arbitrary peak (a) of the particle size distribution measured in the step (2) is used as a reference, the measurement is performed in the step (3) by adding a poor solvent. Obtaining a poor solvent addition amount required for the scattering intensity of the peak (a) to decrease to a predetermined intensity with respect to the reference;
(5) The process of evaluating the lithography characteristic of the composition containing the said copolymer for lithography by the difference in the said poor solvent addition amount.
本発明の方法によれば、リソグラフィー用共重合体を含むリソグラフィー用組成物の特性を、実際にリソグラフィー用組成物を調整しなくても評価することができる。
また、本発明の方法によれば、貧溶媒の添加によって、溶液に対する共重合体の濃度を相対的に上げることで、各共重合体の微小な差を拡大して検出できるため、従来の方法では測定の精度や誤差と同程度になってしまうような微小な差異を有する共重合体を比較することができ、高精度の評価が可能である。
According to the method of the present invention, the characteristics of a lithographic composition containing a lithographic copolymer can be evaluated without actually adjusting the lithographic composition.
In addition, according to the method of the present invention, by adding a poor solvent to relatively increase the concentration of the copolymer relative to the solution, a minute difference between the copolymers can be enlarged and detected. In this case, it is possible to compare copolymers having a minute difference that is almost the same as the accuracy and error of measurement, and high accuracy evaluation is possible.
本明細書において、「(メタ)アクリル酸」は、アクリル酸またはメタクリル酸を意味し、「(メタ)アクリロイルオキシ」は、アクリロイルオキシまたはメタクリロイルオキシを意味する。 In the present specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and “(meth) acryloyloxy” means acryloyloxy or methacryloyloxy.
<リソグラフィー用共重合体>
本発明において評価の対象となるリソグラフィー用共重合体は、リソグラフィー工程に用いられる共重合体であれば、特に限定されずに適用することができる。
例えば、レジスト膜の形成に用いられるレジスト用共重合体、レジスト膜の上層に形成される反射防止膜(TARC)、またはレジスト膜の下層に形成される反射防止膜(BARC)の形成に用いられる反射防止膜用共重合体、ギャップフィル膜の形成に用いられるギャップフィル膜用共重合体、トップコート膜の形成に用いられるトップコート膜用共重合体が挙げられる。
<Copolymer for lithography>
The lithography copolymer to be evaluated in the present invention is not particularly limited as long as it is a copolymer used in the lithography process.
For example, it is used for forming a resist copolymer used for forming a resist film, an antireflection film (TARC) formed on the upper layer of the resist film, or an antireflection film (BARC) formed on the lower layer of the resist film. Examples thereof include a copolymer for antireflection film, a copolymer for gap fill film used for forming a gap fill film, and a copolymer for top coat film used for forming a top coat film.
レジスト用共重合体の例としては、酸脱離性基を有する構成単位の1種以上と、極性基を有する構成単位の1種以上とを含む共重合体が挙げられる。 Examples of the copolymer for resist include a copolymer containing one or more structural units having an acid-eliminable group and one or more structural units having a polar group.
反射防止膜用共重合体の例としては、吸光性基を有する構成単位と、レジスト膜と混合を避けるため、硬化剤などと反応して硬化可能なアミノ基、アミド基、ヒドロキシル基、エポキシ基等の反応性官能基を有する構成単位とを含む共重合体が挙げられる。
吸光性基とは、レジスト組成物中の感光成分が感度を有する波長領域の光に対して、高い吸収性能を有する基であり、具体例としては、アントラセン環、ナフタレン環、ベンゼン環、キノリン環、キノキサリン環、チアゾール環等の環構造(任意の置換基を有していてもよい。)を有する基が挙げられる。特に、照射光として、KrFレーザ光が用いられる場合には、アントラセン環又は任意の置換基を有するアントラセン環が好ましく、ArFレーザ光が用いられる場合には、ベンゼン環又は任意の置換基を有するベンゼン環が好ましい。
Examples of the copolymer for antireflection film include a structural unit having a light-absorbing group and an amino group, an amide group, a hydroxyl group, and an epoxy group that can be cured by reacting with a curing agent to avoid mixing with the resist film. And a copolymer containing a structural unit having a reactive functional group.
The light-absorbing group is a group having high absorption performance with respect to light in a wavelength region where the photosensitive component in the resist composition is sensitive. Specific examples include an anthracene ring, naphthalene ring, benzene ring, quinoline ring. , A group having a ring structure (which may have an arbitrary substituent) such as a quinoxaline ring and a thiazole ring. In particular, when KrF laser light is used as irradiation light, an anthracene ring or an anthracene ring having an arbitrary substituent is preferable, and when ArF laser light is used, a benzene ring or a benzene having an arbitrary substituent A ring is preferred.
上記任意の置換基としては、フェノール性水酸基、アルコール性水酸基、カルボキシ基、カルボニル基、エステル基、アミノ基、又はアミド基等が挙げられる。
これらのうち、吸光性基として、保護された又は保護されていないフェノール性水酸基を有するものが、良好な現像性・高解像性の観点から好ましい。
上記吸光性基を有する構成単位・単量体として、例えば、ベンジル(メタ)アクリレート、p−ヒドロキシフェニル(メタ)アクリレート等が挙げられる。
Examples of the optional substituent include a phenolic hydroxyl group, an alcoholic hydroxyl group, a carboxy group, a carbonyl group, an ester group, an amino group, and an amide group.
Among these, those having a protected or unprotected phenolic hydroxyl group as the light absorbing group are preferable from the viewpoint of good developability and high resolution.
Examples of the structural unit / monomer having the light-absorbing group include benzyl (meth) acrylate and p-hydroxyphenyl (meth) acrylate.
ギャップフィル膜用共重合体の例としては、狭いギャップに流れ込むための適度な粘度を有し、レジスト膜や反射防止膜との混合を避けるため、硬化剤などと反応して硬化可能な反応性官能基を有する構成単位を含む共重合体、具体的にはヒドロキシスチレンと、スチレン、アルキル(メタ)アクリレート、ヒドロキシアルキル(メタ)アクリレート等の単量体との共重合体が挙げられる。
液浸リソグラフィーに用いられるトップコート膜用共重合体の例としては、カルボキシル基を有する構成単位を含む共重合体、水酸基が置換したフッ素含有基を有する構成単位を含む共重合体等が挙げられる。
As an example of a gap fill film copolymer, it has a suitable viscosity for flowing into a narrow gap, and reacts with a curing agent in order to avoid mixing with a resist film or an antireflection film. Examples include a copolymer containing a structural unit having a functional group, specifically, a copolymer of hydroxystyrene and a monomer such as styrene, alkyl (meth) acrylate, or hydroxyalkyl (meth) acrylate.
Examples of the copolymer for the topcoat film used for immersion lithography include a copolymer containing a structural unit having a carboxyl group, a copolymer containing a structural unit having a fluorine-containing group substituted with a hydroxyl group, and the like. .
これらのリソグラフィー用共重合体を分子設計通りに共重合反応させることは容易でなく、分子量や単量体の組成比にばらつきが生じる。また分子設計が同じでも、製造方法が違うと、分子量や単量体の組成比におけるばらつきの度合いが異なり、リソグラフィー工程にあってはかかる製造方法の違いだけでも性能に差が生じ得る。本発明の評価方法によれば、そのような製造方法の違いによる性能の差も評価できるため、リソグラフィー用共重合体は本発明における評価対象の共重合体として好ましい。 It is not easy to copolymerize these lithographic copolymers according to the molecular design, resulting in variations in molecular weight and monomer composition ratio. Even if the molecular design is the same, if the manufacturing method is different, the degree of variation in the molecular weight and the composition ratio of the monomers is different, and in the lithography process, the difference in performance can be caused only by the difference in the manufacturing method. According to the evaluation method of the present invention, the difference in performance due to such a difference in the production method can also be evaluated, so that the copolymer for lithography is preferred as the copolymer to be evaluated in the present invention.
<レジスト用共重合体>
以下、リソグラフィー用共重合体の代表例としてレジスト用共重合体(以下、単に共重合体ということもある。)を挙げて本発明を説明するが、他のリソグラフィー用共重合体も同様に適用できる。
レジスト用共重合体は、レジスト膜の形成に用いられる共重合体であれば、特に限定されずに適用することができる。
<Copolymer for resist>
Hereinafter, the present invention will be described by taking a resist copolymer (hereinafter sometimes simply referred to as a copolymer) as a representative example of a lithography copolymer, but other lithographic copolymers are also applicable. it can.
The resist copolymer is not particularly limited as long as it is a copolymer used for forming a resist film.
具体的には、酸脱離性基を有する構成単位の1種以上と、極性基を有する構成単位の1種以上とを含むレジスト用共重合体が好ましい。該レジスト用共重合体は、酸脱離性基を有する単量体の1種以上と、極性基を有する単量体の1種以上とからなる単量体混合物を重合して得られる。 Specifically, a resist copolymer containing at least one structural unit having an acid leaving group and at least one structural unit having a polar group is preferable. The resist copolymer is obtained by polymerizing a monomer mixture composed of one or more monomers having an acid leaving group and one or more monomers having a polar group.
[酸脱離性基を有する構成単位・単量体]
「酸脱離性基」とは、酸により開裂する結合を有する基であり、該結合の開裂により酸脱離性基の一部または全部が共重合体の主鎖から脱離する基である。
酸脱離性基を有する構成単位を含む共重合体は、レジスト組成物として用いた場合、酸によってアルカリに可溶となり、レジストパターンの形成を可能とする作用を奏する。
酸脱離性基を有する構成単位の含有量は、感度および解像度の点から、共重合体を構成する全構成単位のうち、20モル%以上が好ましく、25モル%以上がより好ましい。また、基板等への密着性の点から、60モル%以下が好ましく、55モル%以下がより好ましく、50モル%以下がさらに好ましい。
[Structural Unit / Monomer Having Acid Leaving Group]
The “acid-leaving group” is a group having a bond that is cleaved by an acid, and a part or all of the acid-leaving group is eliminated from the main chain of the copolymer by cleavage of the bond. .
When used as a resist composition, a copolymer containing a structural unit having an acid-eliminable group is soluble in an alkali by an acid, and has an effect of enabling the formation of a resist pattern.
In view of sensitivity and resolution, the content of the structural unit having an acid leaving group is preferably 20 mol% or more, more preferably 25 mol% or more, of all the structural units constituting the copolymer. Moreover, 60 mol% or less is preferable from the point of the adhesiveness to a board | substrate etc., 55 mol% or less is more preferable, and 50 mol% or less is further more preferable.
酸脱離性基を有する単量体は、酸脱離性基、および重合性多重結合を有する化合物であればよく、公知のものを使用できる。重合性多重結合とは重合反応時に開裂して共重合鎖を形成する多重結合であり、エチレン性二重結合が好ましい。 The monomer having an acid leaving group may be a compound having an acid leaving group and a polymerizable multiple bond, and known ones can be used. The polymerizable multiple bond is a multiple bond that is cleaved during the polymerization reaction to form a copolymer chain, and an ethylenic double bond is preferable.
酸脱離性基を有する単量体の具体例として、炭素数6〜20の脂環式炭化水素基を有し、かつ酸脱離性基を有している(メタ)アクリル酸エステルが挙げられる。該脂環式炭化水素基は、(メタ)アクリル酸エステルのエステル結合を構成する酸素原子と直接結合していてもよく、アルキレン基等の連結基を介して結合していてもよい。
該(メタ)アクリル酸エステルには、炭素数6〜20の脂環式炭化水素基を有するとともに、(メタ)アクリル酸エステルのエステル結合を構成する酸素原子との結合部位に第3級炭素原子を有する(メタ)アクリル酸エステル、または、炭素数6〜20の脂環式炭化水素基を有するとともに、該脂環式炭化水素基に−COOR基(Rは置換基を有していてもよい第3級炭化水素基、テトラヒドロフラニル基、テトラヒドロピラニル基、またはオキセパニル基を表す。)が直接または連結基を介して結合している(メタ)アクリル酸エステルが含まれる。
Specific examples of the monomer having an acid leaving group include (meth) acrylic acid esters having an alicyclic hydrocarbon group having 6 to 20 carbon atoms and having an acid leaving group. It is done. The alicyclic hydrocarbon group may be directly bonded to an oxygen atom constituting an ester bond of (meth) acrylic acid ester, or may be bonded via a linking group such as an alkylene group.
The (meth) acrylic acid ester has an alicyclic hydrocarbon group having 6 to 20 carbon atoms, and a tertiary carbon atom at the bonding site with the oxygen atom constituting the ester bond of the (meth) acrylic acid ester. A (meth) acrylic acid ester having an alicyclic group or an alicyclic hydrocarbon group having 6 to 20 carbon atoms and a -COOR group (R may have a substituent) on the alicyclic hydrocarbon group. (Meth) acrylic acid ester in which a tertiary hydrocarbon group, a tetrahydrofuranyl group, a tetrahydropyranyl group, or an oxepanyl group is bonded directly or via a linking group is included.
特に、波長250nm以下の光で露光するパターン形成方法に適用されるレジスト組成物を製造する場合には、酸脱離性基を有する単量体の好ましい例として、例えば、2−メチル−2−アダマンチル(メタ)アクリレート、2−エチル−2−アダマンチル(メタ)アクリレート、1−(1’−アダマンチル)−1−メチルエチル(メタ)アクリレート、1−メチルシクロヘキシル(メタ)アクリレート、1−エチルシクロヘキシル(メタ)アクリレート、1−メチルシクロペンチル(メタ)アクリレート、1−エチルシクロペンチル(メタ)アクリレート等が挙げられる。
酸脱離性基を有する単量体は、1種を単独で用いてもよく、2種以上を組み合わせて用いてもよい。
In particular, in the case of producing a resist composition that is applied to a pattern forming method that is exposed to light having a wavelength of 250 nm or less, as a preferred example of a monomer having an acid leaving group, for example, 2-methyl-2- Adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, 1- (1′-adamantyl) -1-methylethyl (meth) acrylate, 1-methylcyclohexyl (meth) acrylate, 1-ethylcyclohexyl ( And (meth) acrylate, 1-methylcyclopentyl (meth) acrylate, 1-ethylcyclopentyl (meth) acrylate and the like.
As the monomer having an acid leaving group, one type may be used alone, or two or more types may be used in combination.
[極性基を有する構成単位・単量体]
「極性基」とは、極性を持つ官能基または極性を持つ原子団を有する基であり、具体例としては、ヒドロキシ基、シアノ基、アルコキシ基、カルボキシ基、アミノ基、カルボニル基、フッ素原子を含む基、硫黄原子を含む基、ラクトン骨格を含む基、アセタール構造を含む基、エーテル結合を含む基などが挙げられる。
これらのうちで、波長250nm以下の光で露光するパターン形成方法に適用されるレジスト用共重合体は、極性基を有する構成単位として、ラクトン骨格を有する構成単位を有することが好ましく、さらに後述の親水性基を有する構成単位を有することが好ましい。
[Constitutional unit / monomer having a polar group]
The “polar group” is a group having a polar functional group or a polar atomic group. Specific examples include a hydroxy group, a cyano group, an alkoxy group, a carboxy group, an amino group, a carbonyl group, and a fluorine atom. A group containing a sulfur atom, a group containing a lactone skeleton, a group containing an acetal structure, a group containing an ether bond, and the like.
Among these, the resist copolymer applied to the pattern forming method that is exposed to light having a wavelength of 250 nm or less preferably has a structural unit having a lactone skeleton as the structural unit having a polar group. It is preferable to have a structural unit having a hydrophilic group.
(ラクトン骨格を有する構成単位・単量体)
ラクトン骨格としては、例えば、4〜20員環程度のラクトン骨格が挙げられる。ラクトン骨格は、ラクトン環のみの単環であってもよく、ラクトン環に脂肪族または芳香族の炭素環または複素環が縮合していてもよい。
共重合体がラクトン骨格を有する構成単位を含む場合、その含有量は、基板等への密着性の点から、全構成単位(100モル%)のうち、20モル%以上が好ましく、35モル%以上がより好ましい。また、感度および解像度の点から、60モル%以下が好ましく、55モル%以下がより好ましく、50モル%以下がさらに好ましい。
(Constitutional unit / monomer having a lactone skeleton)
Examples of the lactone skeleton include a lactone skeleton having about 4 to 20 members. The lactone skeleton may be a monocycle having only a lactone ring, or an aliphatic or aromatic carbocyclic or heterocyclic ring may be condensed with the lactone ring.
When the copolymer includes a structural unit having a lactone skeleton, the content thereof is preferably 20 mol% or more of all structural units (100 mol%) from the viewpoint of adhesion to a substrate and the like, and 35 mol%. The above is more preferable. Moreover, from the point of a sensitivity and resolution, 60 mol% or less is preferable, 55 mol% or less is more preferable, and 50 mol% or less is more preferable.
ラクトン骨格を有する単量体としては、基板等への密着性に優れる点から、置換あるいは無置換のδ−バレロラクトン環を有する(メタ)アクリル酸エステル、置換あるいは無置換のγ−ブチロラクトン環を有する単量体からなる群から選ばれる少なくとも1種が好ましく、無置換のγ−ブチロラクトン環を有する単量体が特に好ましい。 As a monomer having a lactone skeleton, a (meth) acrylic acid ester having a substituted or unsubstituted δ-valerolactone ring, a substituted or unsubstituted γ-butyrolactone ring is used because of its excellent adhesion to a substrate or the like. Preferably, at least one selected from the group consisting of monomers having it is preferred, and monomers having an unsubstituted γ-butyrolactone ring are particularly preferred.
ラクトン骨格を有する単量体の具体例としては、β−(メタ)アクリロイルオキシ−β−メチル−δ−バレロラクトン、4,4−ジメチル−2−メチレン−γ−ブチロラクトン、β−(メタ)アクリロイルオキシ−γ−ブチロラクトン、β−(メタ)アクリロイルオキシ−β−メチル−γ−ブチロラクトン、α−(メタ)アクリロイルオキシ−γ−ブチロラクトン、2−(1−(メタ)アクリロイルオキシ)エチル−4−ブタノリド、(メタ)アクリル酸パントイルラクトン、5−(メタ)アクリロイルオキシ−2,6−ノルボルナンカルボラクトン、8−メタクリロキシ−4−オキサトリシクロ[5.2.1.02,6 ]デカン−3−オン、9−メタクリロキシ−4−オキサトリシクロ[5.2.1.02,6 ]デカン−3−オン等が挙げられる。また、類似構造を持つ単量体として、メタクリロイルオキシこはく酸無水物等も挙げられる。
ラクトン骨格を有する単量体は、1種を単独で用いてもよく、2種以上を組み合わせて用いてもよい。
Specific examples of the monomer having a lactone skeleton include β- (meth) acryloyloxy-β-methyl-δ-valerolactone, 4,4-dimethyl-2-methylene-γ-butyrolactone, β- (meth) acryloyl. Oxy-γ-butyrolactone, β- (meth) acryloyloxy-β-methyl-γ-butyrolactone, α- (meth) acryloyloxy-γ-butyrolactone, 2- (1- (meth) acryloyloxy) ethyl-4-butanolide , (Meth) acrylic acid pantoyl lactone, 5- (meth) acryloyloxy-2,6-norbornanecarbolactone, 8-methacryloxy-4-oxatricyclo [5.2.1.0 2,6 ] decane-3 -One, 9-methacryloxy-4-oxatricyclo [5.2.1.0 2,6 ] decan-3-one and the like. Examples of the monomer having a similar structure include methacryloyloxysuccinic anhydride.
Monomers having a lactone skeleton may be used alone or in combination of two or more.
(親水性基を有する構成単位・単量体)
本明細書における「親水性基」とは、−C(CF3)2−OH、ヒドロキシ基、シアノ基、メトキシ基、カルボキシ基およびアミノ基の少なくとも1種である。
これらのうちで、波長250nm以下の光で露光するパターン形成方法に適用されるレジスト用共重合体は、親水性基としてヒドロキシ基、シアノ基を有することが好ましい。
共重合体における親水性基を有する構成単位の含有量は、レジストパターン矩形性の点から、全構成単位(100モル%)のうち、5〜30モル%が好ましく、10〜25モル%がより好ましい。
(Structural unit / monomer having a hydrophilic group)
The “hydrophilic group” in the present specification is at least one of —C (CF 3 ) 2 —OH, a hydroxy group, a cyano group, a methoxy group, a carboxy group, and an amino group.
Among these, it is preferable that the copolymer for resist applied to the pattern formation method exposed with the light of wavelength 250nm or less has a hydroxyl group and a cyano group as a hydrophilic group.
The content of the structural unit having a hydrophilic group in the copolymer is preferably 5 to 30 mol%, more preferably 10 to 25 mol%, of the total structural units (100 mol%) from the viewpoint of resist pattern rectangularity. preferable.
親水性基を有する単量体としては、例えば、末端ヒドロキシ基を有する(メタ)アクリ酸エステル、単量体の親水性基上にアルキル基、ヒドロキシ基、カルボキシ基等の置換基を有する誘導体、環式炭化水素基を有する単量体((メタ)アクリル酸シクロヘキシル、(メタ)アクリル酸1−イソボルニル、(メタ)アクリル酸アダマンチル、(メタ)アクリル酸トリシクロデカニル、(メタ)アクリル酸ジシクロペンチル、(メタ)アクリル酸2−メチル−2−アダマンチル、(メタ)アクリル酸2−エチル−2−アダマンチル等。)が置換基としてヒドロキシ基、カルボキシ基等の親水性基を有する単量体が挙げられる。 As the monomer having a hydrophilic group, for example, a (meth) acrylic acid ester having a terminal hydroxy group, a derivative having a substituent such as an alkyl group, a hydroxy group, or a carboxy group on the hydrophilic group of the monomer, Monomers having a cyclic hydrocarbon group (cyclohexyl (meth) acrylate, 1-isobornyl (meth) acrylate, adamantyl (meth) acrylate), tricyclodecanyl (meth) acrylate, dimethacrylate (meth) acrylate Cyclopentyl, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, etc.) having a hydrophilic group such as a hydroxy group or a carboxy group as a substituent. Can be mentioned.
親水性基を有する単量体の具体例としては、(メタ)アクリル酸、(メタ)アクリル酸2−ヒドロキシエチル、(メタ)アクリル酸3−ヒドロキシプロピル、(メタ)アクリル酸2−ヒドロキシ−n−プロピル、(メタ)アクリル酸4−ヒドロキシブチル、(メタ)アクリル酸3−ヒドロキシアダマンチル、2−または3−シアノ−5−ノルボルニル(メタ)アクリレート、2−シアノメチル−2−アダマンチル(メタ)アクリレート等が挙げられる。基板等に対する密着性の点から、(メタ)アクリル酸3−ヒドロキシアダマンチル、2−または3−シアノ−5−ノルボルニル(メタ)アクリレート、2−シアノメチル−2−アダマンチル(メタ)アクリレート等が好ましい。
親水性基を有する単量体は、1種を単独で用いてもよく、2種以上を組み合わせて用いてもよい。
Specific examples of the monomer having a hydrophilic group include (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxy- (meth) acrylate. -Propyl, 4-hydroxybutyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, 2- or 3-cyano-5-norbornyl (meth) acrylate, 2-cyanomethyl-2-adamantyl (meth) acrylate, etc. Is mentioned. From the viewpoint of adhesion to a substrate or the like, 3-hydroxyadamantyl (meth) acrylate, 2- or 3-cyano-5-norbornyl (meth) acrylate, 2-cyanomethyl-2-adamantyl (meth) acrylate and the like are preferable.
The monomer which has a hydrophilic group may be used individually by 1 type, and may be used in combination of 2 or more type.
<リソグラフィー用共重合体の製造方法>
以下、リソグラフィー用共重合体の製造方法の代表例としてレジスト用共重合体の製造方法を挙げて説明するが、他のリソグラフィー用共重合体も同様に適用できる。
レジスト用共重合体は、ラジカル重合法によって得ることができる。重合方法は特に限定されず、塊状重合法、溶液重合法、懸濁重合法、乳化重合法等の公知の方法を適宜用いることができる。
特に、光線透過率を低下させないために、重合反応終了後に残存する単量体を除去する工程を容易に行える点、重合体の分子量を比較的低くしやすい点から、溶液ラジカル重合法が好ましい。そのうちで、製造ロットの違いによる平均分子量、分子量分布等のばらつきが小さく、再現性のある重合体を簡便に得やすい点から、滴下重合法が更に好ましい。
<Method for producing copolymer for lithography>
Hereinafter, a method for producing a resist copolymer will be described as a representative example of a method for producing a lithographic copolymer, but other lithographic copolymers can be similarly applied.
The resist copolymer can be obtained by radical polymerization. The polymerization method is not particularly limited, and a known method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method can be appropriately used.
In particular, the solution radical polymerization method is preferred from the viewpoint that the step of removing the monomer remaining after the completion of the polymerization reaction can be easily performed and the molecular weight of the polymer can be relatively easily lowered in order not to reduce the light transmittance. Among them, the drop polymerization method is more preferable from the viewpoint that a variation in average molecular weight, molecular weight distribution, etc. due to the difference in production lot is small and a reproducible polymer can be easily obtained.
滴下重合法においては、重合容器内を所定の重合温度まで加熱した後、単量体及び重合開始剤を、各々独立に、又は任意の組み合わせで、重合容器内に滴下する。単量体は、単量体のみで滴下してもよく、又は単量体を溶媒に溶解させた単量体溶液として滴下してもよい。重合容器に予め溶媒を仕込んでもよく、仕込まなくてもよい。重合容器に予め溶媒を仕込まない場合、単量体または重合開始剤は、溶媒がない状態で重合容器中に滴下される。 In the dropping polymerization method, the inside of the polymerization vessel is heated to a predetermined polymerization temperature, and then the monomer and the polymerization initiator are dropped into the polymerization vessel independently or in any combination. A monomer may be dripped only with a monomer, or may be dripped as a monomer solution in which a monomer is dissolved in a solvent. The polymerization vessel may be charged with a solvent in advance or may not be charged. When the solvent is not charged in advance in the polymerization vessel, the monomer or the polymerization initiator is dropped into the polymerization vessel in the absence of the solvent.
上記重合開始剤は、単量体に直接に溶解させてもよく、単量体溶液に溶解させてもよく、又は溶媒のみに溶解させてもよい。単量体及び重合開始剤は、同じ貯槽内で混合した後、重合容器中に滴下してもよく、各々独立した貯槽から重合容器中に滴下してもよい。または、各々独立した貯槽から重合容器に供給する直前で混合して、重合容器中に滴下してもよい。上記単量体及び重合開始剤は、一方を先に滴下した後、遅れて他方を滴下してもよく、両方を同じタイミングで滴下してもよい。
なお、滴下速度は、滴下終了まで一定であってもよく、又は単量体や重合開始剤の消費速度に応じて、多段階に変化させてもよい。滴下は、連続的又は間欠的に行ってもよい。
The polymerization initiator may be dissolved directly in the monomer, dissolved in the monomer solution, or dissolved only in the solvent. The monomer and the polymerization initiator may be dropped into the polymerization vessel after mixing in the same storage tank, or may be dropped from the independent storage tank into the polymerization container. Alternatively, they may be mixed immediately before being supplied from independent storage tanks to the polymerization vessel and dropped into the polymerization vessel. One of the monomers and the polymerization initiator may be dropped first, and then the other may be dropped with a delay, or both may be dropped at the same timing.
The dropping speed may be constant until the dropping is completed, or may be changed in multiple stages according to the consumption speed of the monomer or the polymerization initiator. The dripping may be performed continuously or intermittently.
上記溶液ラジカル重合による滴下重合法を用いる場合、重合初期に重合開始剤及び/又は単量体の供給速度を上げて高分子量体の生成を抑制する方法を用いることができる。
一般的に、滴下重合法において、単量体と重合開始剤を同一滴下時間、かつ均一速度で滴下する場合、重合初期に高分子量体が生成する傾向がある。そこで、重合初期に重合開始剤の供給速度を上げることにより、重合開始剤の分解を促進させて、ラジカルの生成・失活を定常的に発生させ、該ラジカル中に単量体を滴下することで、重合初期における高分子量体の生成を抑制することができる。具体的には、二種以上の滴下液を調製し、各々の滴下液の供給速度を多段階に変化させる方法や、重合容器内に予め溶剤と重合開始剤の一部量又は全量を仕込み、次いで、各種単量体及び/又は残りの重合開始剤等を含有する滴下液を滴下する方法等が挙げられる。
In the case of using the dropping polymerization method based on the solution radical polymerization, a method of suppressing the formation of a high molecular weight body by increasing the supply rate of the polymerization initiator and / or monomer at the initial stage of polymerization can be used.
Generally, in the dropping polymerization method, when the monomer and the polymerization initiator are dropped at the same dropping time and at a uniform rate, a high molecular weight product tends to be formed at the initial stage of polymerization. Therefore, by increasing the supply rate of the polymerization initiator at the initial stage of polymerization, the decomposition of the polymerization initiator is promoted, radical generation / deactivation is constantly generated, and the monomer is dropped into the radical. Thus, the formation of a high molecular weight product in the initial stage of polymerization can be suppressed. Specifically, two or more kinds of dropping liquids are prepared, and a method of changing the supply rate of each dropping liquid in multiple stages, or a solvent and a polymerization initiator are partially or completely charged in advance in a polymerization vessel, Then, the method etc. of dripping the dripping liquid containing various monomers and / or the remaining polymerization initiator, etc. are mentioned.
また一般的に、滴下重合法において、反応性の異なる2種以上の単量体と重合開始剤を同一滴下時間、かつ均一速度で滴下する場合、反応性の高い単量体の重合が先に進行し、その結果、特に重合初期に生成する高分子量体の中に、組成が不均一な共重合体が多く含まれる傾向がある。
かかる重合初期における、組成の不均一な高分子量体の生成を抑制する方法として、例えば、重合に用いられる各単量体の反応性比に応じて、反応器内にモノマーを先仕込みして、重合初期から定常状態で重合させることにより、組成の均一なポリマーを製造する方法がある。
In general, in the dropping polymerization method, when two or more monomers having different reactivity and a polymerization initiator are dropped at the same dropping time and at a uniform rate, the polymerization of the highly reactive monomer is first performed. As a result, the copolymer having a non-uniform composition tends to be included in the high molecular weight product generated particularly at the initial stage of polymerization.
As a method of suppressing the formation of a high molecular weight polymer having a non-uniform composition at the initial stage of polymerization, for example, according to the reactivity ratio of each monomer used for polymerization, a monomer is charged in advance in the reactor, There is a method for producing a polymer having a uniform composition by polymerizing in a steady state from the initial stage of polymerization.
更に、上記重合初期における高分子量体の生成を抑制する方法と、上記重合初期における、組成の不均一な高分子量体の生成を抑制する方法とを組み合わせると、分子量及び組成が更に均一な共重合体を得ることができるため好ましい。 Furthermore, when the method for suppressing the formation of a high molecular weight body in the initial stage of polymerization and the method for suppressing the formation of a high molecular weight body having a non-uniform composition in the initial stage of polymerization are combined, Since coalescence can be obtained, it is preferable.
上記製造方法によれば、共重合体における構成単位の組成比や分子量のばらつきが小さくなりやすい。構成単位の組成比や分子量のばらつきが小さいと、溶媒への溶解性が良好であり、かつレジスト組成物に用いたときに高い感度が得られる。 According to the said manufacturing method, the dispersion | variation in the composition ratio and molecular weight of the structural unit in a copolymer tends to become small. When the variation in the composition ratio and molecular weight of the structural units is small, the solubility in a solvent is good, and high sensitivity is obtained when used in a resist composition.
<評価方法>
本発明の評価方法は、下記工程を含む:
(1)リソグラフィー用共重合体を溶媒に溶解させて試験溶液を調製する工程;
(2)動的光散乱法を用いて、前記試験溶液の粒径分布における散乱強度を測定する工程;
(3)前記試験溶液に貧溶媒を添加し、動的光散乱法を用いて、前記貧溶媒添加後の試験溶液の粒径分布における散乱強度を測定する工程;
(4)前記(2)工程において測定される、粒径分布の任意のピーク(a)の散乱強度を基準とした場合に、貧溶媒の添加により、前記(3)工程において測定される、前記ピーク(a)の散乱強度が、前記基準に対して所定の強度に減少するまでに要する貧溶媒添加量を求める工程;
(5)前記貧溶媒添加濃度の差異により、前記リソグラフィー用共重合体を含む組成物のリソグラフィー特性を評価する工程。
<Evaluation method>
The evaluation method of the present invention includes the following steps:
(1) a step of preparing a test solution by dissolving a copolymer for lithography in a solvent;
(2) a step of measuring the scattering intensity in the particle size distribution of the test solution using a dynamic light scattering method;
(3) adding a poor solvent to the test solution and measuring a scattering intensity in a particle size distribution of the test solution after the poor solvent is added using a dynamic light scattering method;
(4) When the scattering intensity of an arbitrary peak (a) of the particle size distribution measured in the step (2) is used as a reference, the measurement is performed in the step (3) by adding a poor solvent. Obtaining a poor solvent addition amount required for the scattering intensity of the peak (a) to decrease to a predetermined intensity with respect to the reference;
(5) The process of evaluating the lithography characteristic of the composition containing the said copolymer for lithography by the difference in the said poor solvent addition density | concentration.
<(1)工程>
上記試験溶液は、レジスト用共重合体を溶媒に溶解させて調製する。上記溶媒は、良溶媒であることが好ましい。試験溶液中におけるレジスト用共重合体の含有量は、15質量%〜25質量%が好ましく、18質量%〜22質量%が更に好ましい。なお、上記レジスト用共重合体は、良溶媒に完全に溶解していることが好ましい。
本評価方法では、貧溶媒の添加によって、溶液に対する共重合体の濃度を相対的に上げ、良好に溶解する濃度から飽和に近づく変化の様子を観察している。15質量%〜25質量%の濃度であれば、飽和状態に解離しすぎず、近すぎもしないため、貧溶媒の添加による、良好に溶解する状態から飽和状態への変化が最も観察しやすい。
また、本評価方法では、貧溶媒の添加による粒子の増大の様子を観察しているが、重合体が溶媒に完全に溶解していない場合、溶解していない粒子を核として、粒子の増大が生じる場合があり、完全に溶解していない溶液は、本評価方法には望ましくない。
<(1) Process>
The test solution is prepared by dissolving a resist copolymer in a solvent. The solvent is preferably a good solvent. The content of the resist copolymer in the test solution is preferably 15% by mass to 25% by mass, and more preferably 18% by mass to 22% by mass. The resist copolymer is preferably completely dissolved in a good solvent.
In this evaluation method, by adding a poor solvent, the concentration of the copolymer relative to the solution is relatively increased, and a state of change approaching saturation from a concentration that dissolves well is observed. If the concentration is 15% by mass to 25% by mass, it does not dissociate too much into a saturated state, nor is it too close, so the change from a well-dissolved state to a saturated state due to the addition of a poor solvent is most easily observed.
In addition, in this evaluation method, the state of increase in particles due to the addition of a poor solvent is observed. If the polymer is not completely dissolved in the solvent, the increase in particles is caused by using the undissolved particles as nuclei. Solutions that may occur and are not completely dissolved are undesirable for the evaluation method.
本明細書における良溶媒とは、常温(25℃)において、レジスト用共重合体を、5質量倍量以下の溶媒量で完全に溶解できる溶媒をいう。特に3質量倍量以下の溶媒量でレジスト用共重合体を完全に溶解できるものを用いることが好ましい。試験溶液に用いる良溶媒は1種単独の溶媒でもよく2種以上の混合物でもよい。混合溶媒の場合は、混合後に上記良溶媒の条件を満たすものであれば、良溶媒として用いることができる。
なお、本明細書において、「完全に溶解」とは、溶液に溶解しているレジスト用共重合体を用いて形成されたレジスト膜が、透明性を示さない波長を用いて測定された透過率が100%である状態を言う。例えばレジスト用共重合体がアクリル系重合体である場合には、測定波長として可視光領域の波長が好ましく、具体的には380nm〜780nmが好適である。
The good solvent in this specification refers to a solvent that can completely dissolve the resist copolymer in a solvent amount of 5 mass times or less at room temperature (25 ° C.). In particular, it is preferable to use a solvent that can completely dissolve the resist copolymer with a solvent amount of 3 mass times or less. The good solvent used for the test solution may be a single solvent or a mixture of two or more. In the case of a mixed solvent, any solvent can be used as long as it satisfies the above-mentioned good solvent conditions after mixing.
In the present specification, “completely dissolved” refers to a transmittance measured using a wavelength at which a resist film formed using a resist copolymer dissolved in a solution does not exhibit transparency. Is 100%. For example, when the resist copolymer is an acrylic polymer, the wavelength in the visible light region is preferable as the measurement wavelength, and specifically, 380 nm to 780 nm is preferable.
一方、貧溶媒とは、常温(25℃)において、レジスト用共重合体に対し、5質量倍量の単独溶媒を加えて撹拌しても全く溶解しない溶媒をいう。特に10質量倍量の単独溶媒を加えても全く溶解しないものを用いることが好ましい。混合溶媒の場合は、混合後に上記貧溶媒の条件を満たすものであれば、貧溶媒として用いることができる。 On the other hand, the poor solvent means a solvent that does not dissolve at all even when a 5 mass-fold amount of a single solvent is added to the resist copolymer and stirred at room temperature (25 ° C.). In particular, it is preferable to use a solvent that does not dissolve at all even when a 10 mass-fold amount of a single solvent is added. In the case of a mixed solvent, it can be used as a poor solvent as long as it satisfies the above poor solvent conditions after mixing.
良溶媒としては、レジスト組成物を調製する際に用いられる公知のレジスト溶媒から適宜選択して用いることができる。1種単独で用いてもよいし、2種以上を組み合わせて用いてもよい。
好ましい良溶媒の具体例としては、テトラヒドロフラン、1,4―ジオキサン、アセトン、メチルエチルケトン、メチルイソブチルケトン、プロピレングリコールモノメチルエーテル、プロピレングリコールモノメチルエーテルアセテート、乳酸メチル、乳酸エチル、乳酸ブチル、γ−ブチロラクトンなどが挙げられる。
As a good solvent, it can select from the well-known resist solvent used when preparing a resist composition suitably, and can use it. You may use individually by 1 type and may be used in combination of 2 or more type.
Specific examples of preferable good solvents include tetrahydrofuran, 1,4-dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, and γ-butyrolactone. Can be mentioned.
貧溶媒としては、ペンタン、ヘキサン、ヘプタン、オクタン、シクロヘキサン、メチルシクロヘキサン、ベンゼン、トルエン、キシレン、ジエチルエーテル、ジイソプロピルエーテル、メタノール、エタノール、イソプロパノール、水などを用いることができる。貧溶媒は1種単独で用いてもよいし、2種以上を組み合わせて用いてもよい。
特に、評価対象のレジスト用共重合体がアクリル系共重合体である場合、良溶媒としてPGMEA(プロピレングリコールモノメチルエーテルアセテート)、乳酸エチル、THF(テトラヒドロフラン)を用い、貧溶媒としてIPE(ジイソプロピルエーテル)、ヘキサン、ヘプタン、メタノールを用いることが好ましい。
As the poor solvent, pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, diethyl ether, diisopropyl ether, methanol, ethanol, isopropanol, water, and the like can be used. A poor solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
In particular, when the resist copolymer to be evaluated is an acrylic copolymer, PGMEA (propylene glycol monomethyl ether acetate), ethyl lactate, THF (tetrahydrofuran) is used as a good solvent, and IPE (diisopropyl ether) is used as a poor solvent. , Hexane, heptane, and methanol are preferably used.
<(2)工程>
上記試験溶液調整後、動的光散乱法を用いて、前記試験溶液の粒径分布における散乱強度を測定する。なお、一般に粒径分布を測定する方法としては、例えば、レーザー回折法、遠心沈降法、FFF法(Field Flow Fractionation)、電気的検知帯法等が挙げられるが、本発明では、重合体の粒径、溶液状態での測定が可能などの点から、動的光散乱法を用いて評価を行った。
<(2) Process>
After the test solution is prepared, the scattering intensity in the particle size distribution of the test solution is measured using a dynamic light scattering method. In general, examples of the method for measuring the particle size distribution include a laser diffraction method, a centrifugal sedimentation method, an FFF method (Field Flow Fractionation), an electrical detection band method, and the like. Evaluation was performed using the dynamic light scattering method from the point where the measurement in the diameter and the solution state was possible.
粒径分布測定の測定温度は、特に限定されないが、15℃〜35℃が好ましく、より好ましくは、20℃〜30℃である。粒径分布には溶液粘度が関連しており、溶液粘度は温度に敏感であるため、温度が安定しやすい、室温に近い温度で測定を行うことが好ましい。 Although the measurement temperature of particle size distribution measurement is not specifically limited, 15 to 35 degreeC is preferable, More preferably, it is 20 to 30 degreeC. Since the solution viscosity is related to the particle size distribution, and the solution viscosity is sensitive to temperature, it is preferable to perform the measurement at a temperature close to room temperature where the temperature tends to be stable.
<(3)工程>
次いで、上記試験溶液に、貧溶媒を添加した後に、動的光散乱法を用いて、試験溶液の粒径分布における散乱強度を測定する。
<(3) Process>
Next, after adding a poor solvent to the test solution, the scattering intensity in the particle size distribution of the test solution is measured using a dynamic light scattering method.
上記(2)工程同様に、粒径分布測定の測定温度は、特に限定されないが、15℃〜35℃が好ましく、より好ましくは、20℃〜30℃である。粒径分布には溶液粘度が関連しており、溶液粘度は温度に敏感であるため、温度が安定しやすい、室温に近い温度で測定を行うことが好ましい。
また、貧溶媒については、上述のとおりである。
As in the step (2), the measurement temperature for the particle size distribution measurement is not particularly limited, but is preferably 15 ° C to 35 ° C, and more preferably 20 ° C to 30 ° C. Since the solution viscosity is related to the particle size distribution, and the solution viscosity is sensitive to temperature, it is preferable to perform the measurement at a temperature close to room temperature where the temperature tends to be stable.
The poor solvent is as described above.
<(4)工程>
次いで、前記(2)工程において測定される、粒径分布の任意のピーク(a)の散乱強度を基準とした場合に、貧溶媒の添加により、前記(3)工程において測定される、前記ピーク(a)の散乱強度が、前記基準に対する所定の強度に減少するまでに要する貧溶媒添加量を求める。
なお、貧溶媒を徐々に添加することにより、上記散乱強度の減少が生じる理由として、貧溶媒の添加により、高分子量体や組成の不均一な重合体が析出しやすくなり、共重合体粒子の凝集等が生じて、粒径分布に変化が生じるためと考えられる。
上記貧溶媒添加量を求める方法は、特に限定されないが、例えば、下記方法により測定することができる。
<(4) Process>
Next, when the scattering intensity of an arbitrary peak (a) in the particle size distribution measured in the step (2) is used as a reference, the peak measured in the step (3) by adding a poor solvent A poor solvent addition amount required until the scattering intensity of (a) decreases to a predetermined intensity with respect to the reference is obtained.
The reason why the scattering intensity is reduced by gradually adding the poor solvent is that the addition of the poor solvent facilitates precipitation of a polymer having a high molecular weight or a non-uniform composition. This is probably because agglomeration or the like occurs and the particle size distribution changes.
The method for obtaining the amount of the poor solvent added is not particularly limited, but for example, it can be measured by the following method.
[貧溶媒添加量(M値)を求める方法]
上記(2)工程及び(3)工程で測定される、粒径分布の任意のピーク強度(a)は、特に限定されないが、定量性・再現性の観点から、最大の散乱強度を示す粒径におけるピーク(a)を採用することが好ましい。
また、上記(3)工程において測定される、前記ピーク(a)の散乱強度が、前記基準に対して所定の強度に減少するまでに要する貧溶媒添加量を求める場合の「所定の強度」とは、特に限定されないが、定量性・再現性の観点から、上記基準に対して10%〜90%、好ましくは40%〜60%、更に好ましくは50%の強度とすることが好ましい。
以下、本発明の一実施態様について、貧溶媒無添加時の最大の散乱強度を示す粒径におけるピーク(a)を基準とした場合に貧溶媒の添加により、当該ピーク(a)が、当該基準に対して50%に減少するまでに要する貧溶媒添加量(M値:質量%)と称して説明する。
[Method for Determining Poor Solvent Addition Amount (M Value)]
The arbitrary peak intensity (a) of the particle size distribution measured in the steps (2) and (3) is not particularly limited, but from the viewpoint of quantification and reproducibility, the particle diameter showing the maximum scattering intensity. It is preferable to employ the peak (a).
Further, “predetermined intensity” in the case where the amount of anti-solvent added required for the scattering intensity of the peak (a) to be reduced to a predetermined intensity with respect to the reference is measured in the step (3). Is not particularly limited, but from the viewpoint of quantification and reproducibility, the strength is preferably 10% to 90%, preferably 40% to 60%, and more preferably 50% with respect to the above criteria.
Hereinafter, for one embodiment of the present invention, when the peak (a) in the particle diameter showing the maximum scattering intensity when no poor solvent is added is used as a reference, the peak (a) is converted into the reference by adding the poor solvent. The amount of addition of the poor solvent required to decrease to 50% (M value: mass%) will be described.
まず、レジスト用共重合体の試験溶液(例えば、共重合体濃度が20質量%)を調製し、粒径分布測定を行う。得られる粒径分布から、最大の散乱強度を示す粒径Rにおける散乱強度(S0)を求める。 First, a resist copolymer test solution (for example, the copolymer concentration is 20% by mass) is prepared, and the particle size distribution is measured. From the obtained particle size distribution, the scattering intensity (S 0 ) at the particle diameter R showing the maximum scattering intensity is obtained.
続いて、上記試験溶液に、上記試験溶液に対して、m質量%の貧溶媒を添加し、十分に攪拌を行い、粒径分布測定を行う。得られる粒径分布から、貧溶媒無添加時に最大の散乱強度を示した粒径Rにおける散乱強度Smを求める。さらに、粒径Rにおける散乱強度の、貧溶媒添加による減少を示すSm/S0を求める。 Subsequently, m% by mass of a poor solvent is added to the test solution, the mixture is sufficiently stirred, and the particle size distribution is measured. From the obtained particle size distribution, the scattering intensity S m at the particle diameter R showing the maximum scattering intensity when no poor solvent is added is determined. Furthermore, S m / S 0 indicating a decrease in the scattering intensity at the particle size R due to the addition of the poor solvent is obtained.
ここで、貧溶媒の添加量mは、30%<Sm/S0<70%となる範囲で行うのが好ましく、より好ましくは10%<Sm/S0<90%となる範囲で添加するのがよい。また該範囲でmが、好ましくは4点以上、より好ましくは6点以上とれるように、mの添加量を調節するのが好ましい。これらは、測定点を多く、測定範囲を広くすることで、評価の精度を上げるためである。
得られたデータから、上記粒径Rにおける散乱強度が、貧溶媒の添加によって、Sm/S0=50%となる貧溶媒添加量(濃度)を求め、これをM値(質量%)とする。
上記M値は、測定する試験溶液に含まれる共重合体の物性、共重合体の重量平均分子量や組成の相違、溶液の濃度等により値が異なるため、同組成・同分子量で、重合方法の異なる共重合体同士の比較に用いることが好ましい。
Here, the addition amount m of the poor solvent is preferably 30% <S m / S 0 <70%, more preferably 10% <S m / S 0 <90%. It is good to do. Further, it is preferable to adjust the amount of m added so that m is preferably 4 points or more, more preferably 6 points or more in this range. These are for increasing the accuracy of evaluation by increasing the number of measurement points and widening the measurement range.
From the obtained data, the poor solvent addition amount (concentration) at which the scattering intensity at the particle size R becomes S m / S 0 = 50% by the addition of the poor solvent is determined, and this is referred to as M value (mass%). To do.
The M value varies depending on the physical properties of the copolymer contained in the test solution to be measured, the weight average molecular weight and composition of the copolymer, the concentration of the solution, and the like. It is preferable to use for comparison between different copolymers.
上記M値は、後述の実施例に示されるように、レジスト用共重合体をレジスト組成物としたときの感度と相関している。すなわち、共重合体の物性、共重合体の重量平均分子量や組成等の相違がない場合には、上記M値が大きいほど感度が良い。したがって、上記M値を用いて感度の評価を行うことができる。
また、感度が良いということは、レジスト組成物の露光後のアルカリ溶解性が良好であることを意味しており、例えば、現像欠陥(ディフェクト)、およびパターン寸法のばらつき(LER)等の現像特性も良いと推測される。すなわち、感度が良いということは、現像特性等のリソグラフィー特性も良いと推測される。
The M value correlates with the sensitivity when a resist copolymer is used as a resist composition, as shown in the Examples described later. That is, when there is no difference in the physical properties of the copolymer, the weight average molecular weight or composition of the copolymer, the larger the M value, the better the sensitivity. Therefore, sensitivity can be evaluated using the M value.
In addition, high sensitivity means that the alkali solubility after exposure of the resist composition is good. For example, development characteristics such as development defects (defects) and variations in pattern dimensions (LER). It is speculated that it is also good. That is, it is assumed that the high sensitivity means that the lithography characteristics such as the development characteristics are also good.
なお、後述の実施例に示されるように、貧溶媒の添加により粒径の増大を引き起こしやすい成分は、共重合体のうちでも比較的高分子量の成分であり、かつ構成単位の組成が設計値から比較的大きく外れている成分である。このことから、該成分は共重合体の不均一性を増大させる成分であると考えられる。そして本発明におけるM値が大きいほど、かかる共重合体における均一性が高いことを意味し、均一性が高いために感度等の現像特性が良くなっていると考えられる。
したがって、本発明の評価方法を用いることによって、レジスト用組成物の現像特性の評価だけでなく、リソグラフィー用共重合体の均一性によって変動するリソグラフィー特性の評価が可能である。
In addition, as shown in the examples described later, the component that easily causes an increase in particle size due to the addition of a poor solvent is a relatively high molecular weight component in the copolymer, and the composition of the structural unit is the design value. It is a component that deviates relatively greatly. From this, it is thought that this component is a component which increases the heterogeneity of a copolymer. The larger the M value in the present invention, the higher the uniformity in the copolymer. It is considered that the development characteristics such as sensitivity are improved because the uniformity is high.
Therefore, by using the evaluation method of the present invention, it is possible to evaluate not only the development characteristics of the resist composition but also the lithography characteristics that vary depending on the uniformity of the lithography copolymer.
本発明の評価方法におけるM値が大きいリソグラフィー用共重合体およびこれを含有するリソグラフィー組成物は、共重合体全体における分子量の均一性が高い。したがって、共重合体の分子量の均一性が高いと向上するリソグラフィー特性が良好である。 The lithographic copolymer having a large M value in the evaluation method of the present invention and the lithographic composition containing the copolymer have high molecular weight uniformity throughout the copolymer. Therefore, the lithography properties that are improved when the uniformity of the molecular weight of the copolymer is high are good.
なお、本発明の評価方法は、貧溶媒の添加によって、溶液に対する共重合体の濃度を相対的に上げることで、各共重合体の微小な差を拡大して検出できるため、僅かな構造の差異や現像特性の差異を有する共重合体同士を比較する場合でも、評価方法の精度や誤差による影響を抑えることができ、結果として、高精度な評価を行えると推定される。 In the evaluation method of the present invention, by adding a poor solvent to relatively increase the concentration of the copolymer relative to the solution, a minute difference of each copolymer can be enlarged and detected. Even when comparing copolymers having differences and development characteristics, it is presumed that the influence of accuracy and error of the evaluation method can be suppressed, and as a result, highly accurate evaluation can be performed.
また、同様の原理により、共重合体の析出点(曇点)を評価に用いることもできる。
例えば、レジスト用共重合体の試験溶液に貧溶媒を添加していき、共重合体の析出を目視等で確認した時の貧溶媒添加量(質量%)も、共重合体の均一性と相関するので、現像特性やリソグラフィー特性を評価することが可能である。より定量的には、レジスト用共重合体の試験溶液に、例えば、波長450nmにおける透過率が85±3%となるまで貧溶媒を添加すると、この時析出する成分は、共重合体のうちでも比較的高分子量の成分であり、かつ構成単位の組成が設計値から比較的大きく外れている成分である。このことから、該成分は共重合体の不均一性を増大させる成分であると考えられる。そして本発明における曇点が大きいほど、かかる共重合体における均一性が高いことを意味する。よってM値と同様に、共重合体の均一性の評価をすることで、レジスト用組成物の現像特性やリソグラフィー特性を評価することが可能である。
なお、特に限定されないが、再現性・定量性等の観点から、上記曇点評価は、室温で行うことで好ましい。
Moreover, the precipitation point (cloud point) of a copolymer can also be used for evaluation by the same principle.
For example, when a poor solvent is added to the resist copolymer test solution and the precipitation of the copolymer is visually confirmed, the poor solvent addition amount (% by mass) also correlates with the homogeneity of the copolymer. Therefore, it is possible to evaluate development characteristics and lithography characteristics. More quantitatively, when a poor solvent is added to the test solution of the resist copolymer, for example, until the transmittance at a wavelength of 450 nm is 85 ± 3%, the components precipitated at this time are among the copolymers. It is a component having a relatively high molecular weight and having a composition unit whose composition deviates relatively from the design value. From this, it is thought that this component is a component which increases the heterogeneity of a copolymer. And it means that the uniformity in this copolymer is so high that the cloud point in this invention is large. Therefore, like the M value, it is possible to evaluate the development characteristics and lithography characteristics of the resist composition by evaluating the uniformity of the copolymer.
Although not particularly limited, the cloud point evaluation is preferably performed at room temperature from the viewpoint of reproducibility and quantitativeness.
以下に実施例を用いて本発明をさらに詳しく説明するが、本発明はこれら実施例に限定されるものではない。
下記の製造例1〜4では、極性基を有する単量体としてα−メタクリロイルオキシ−γ−ブチロラクトン(α−GBLMA)、およびメタクリル酸3−ヒドロキシアダマンチル(HAdMA)を用い、酸脱離性基を有する単量体として1−エチルシクロヘキシルメタクリレート(ECHMA)を用いた。分子設計における構成単位の組成比はα−GBLMA:ECHMA:HAdMA=40:40:20(モル%)とし、重合の手順を変えて、4種の共重合体A〜Dを製造した。溶剤および重合開始剤は同じものを使用した。
Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
In the following Production Examples 1 to 4, α-methacryloyloxy-γ-butyrolactone (α-GBLMA) and 3-hydroxyadamantyl methacrylate (HAdMA) are used as monomers having a polar group, and an acid leaving group is used. 1-Ethylcyclohexyl methacrylate (ECHMA) was used as a monomer having the same. The composition ratio of the structural units in the molecular design was α-GBLMA: ECHMA: HAdMA = 40: 40: 20 (mol%), and the polymerization procedure was changed to produce four types of copolymers AD. The same solvent and polymerization initiator were used.
なお、重合の手順の違いにより、ほぼ同等の組成・分子量の共重合体であっても、共重合体全体における構成単位の組成比の均一性等に差異を有する共重合体を得ることができる。 In addition, due to the difference in the polymerization procedure, it is possible to obtain a copolymer having a difference in the uniformity of the composition ratio of structural units in the entire copolymer, even if the copolymer has almost the same composition and molecular weight. .
[製造例1]
(工程1A)窒素導入口、攪拌機、コンデンサー、滴下漏斗及び温度計を備えたフラスコに、窒素雰囲気下で、乳酸エチル72.6部を入れ、攪拌しながら湯浴の温度を80℃に上げた。
(工程2A)α−GBLMA30.6部、ECHMA35.3部、HAdMA21.2部、乳酸エチル130.7部、ジメチル−2,2´−アゾビスイソブチレート(和光純薬工業社製、V−601(製品名))2.6部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程3A)次いで、得られた反応溶液を約7倍量のメタノールと水との混合溶媒(メタノール/水=80/20容量比)に撹拌しながら滴下し、白色のゲル状物の沈殿を得た。得られた沈殿を濾別し、再び約7倍量のメタノールと水との混合溶媒(メタノール/水=85/15容量比)に投入した。これを濾別、回収し、減圧下60℃で約40時間乾燥し、共重合体Aの粉末を得た。
[Production Example 1]
(Step 1A) In a flask equipped with a nitrogen inlet, a stirrer, a condenser, a dropping funnel and a thermometer, 72.6 parts of ethyl lactate was placed under a nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring. .
(Step 2A) α-GBLMA 30.6 parts, ECHMA 35.3 parts, HAdMA 21.2 parts, ethyl lactate 130.7 parts, dimethyl-2,2′-azobisisobutyrate (Wako Pure Chemical Industries, V- A mixed solution obtained by mixing 2.6 parts of 601 (product name) was dropped into the flask at a constant rate from a dropping funnel over 4 hours, and then a temperature of 80 ° C. was maintained for 3 hours.
(Step 3A) Next, the obtained reaction solution was added dropwise to a mixed solvent of methanol and water (methanol / water = 80/20 volume ratio) in an amount of about 7 times while stirring to precipitate a white gel. Obtained. The resulting precipitate was separated by filtration and again poured into a mixed solvent of methanol and water in an amount of about 7 times (methanol / water = 85/15 volume ratio). This was separated by filtration, collected, and dried under reduced pressure at 60 ° C. for about 40 hours to obtain a copolymer A powder.
[製造例2]
(工程1A’)製造例1の工程1Aとの違いは滴下漏斗を2個備えたフラスコを用いた点である。
(工程2A)製造例1の工程2Aと同様にして混合溶液を滴下した。
(工程2B)工程2Aにおける混合溶液の滴下開始と同時に、乳酸エチル3.7部、V−601(製品名)1.2部を混合した混合溶液を別の滴下漏斗より0.1時間かけてフラスコ内に滴下し、さらに80℃の温度を6.9時間保持した。
(工程3A)製造例1の工程3Aと同様の操作を行って共重合体Bの粉末を得た。
[Production Example 2]
(Step 1A ′) The difference from Production Example 1 in Step 1A is that a flask equipped with two dropping funnels was used.
(Step 2A) The mixed solution was added dropwise in the same manner as in Step 2A of Production Example 1.
(Step 2B) Simultaneously with the start of dropping of the mixed solution in Step 2A, a mixed solution obtained by mixing 3.7 parts of ethyl lactate and 1.2 parts of V-601 (product name) was added from another dropping funnel over 0.1 hour. The solution was dropped into the flask, and the temperature of 80 ° C. was further maintained for 6.9 hours.
(Step 3A) The same operation as in step 3A of Production Example 1 was performed to obtain a powder of copolymer B.
[製造例3]
(工程1C)滴下漏斗を2個備えたフラスコを用い、滴下前にフラスコ内に単量体を仕込んだ。すなわち、窒素導入口、攪拌機、コンデンサー、滴下漏斗2個及び温度計を備えたフラスコに、窒素雰囲気下で、乳酸エチル88.8部、α−GBLMA3.1部、ECHMA5.5部、HAdMA2.3部を入れ、攪拌しながら湯浴の温度を80℃に上げた。
(工程2A’)製造例1の工程2Aとは、混合溶液の組成が異なる。すなわちα−GBLMA26.8部、ECHMA30.9部、HAdMA18.6部、乳酸エチル112.5部、V−601(製品名)1.9部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程2B’)製造例2の工程2Bとは、混合溶液の組成が異なる。すなわち、工程2A’における混合溶液の滴下開始と同時に、乳酸エチル1.8部、V−601(製品名)0.7部を混合した混合溶液を別の滴下漏斗より0.1時間かけてフラスコ内に滴下し、さらに80℃の温度を6.9時間保持した。
(工程3A)製造例1の工程3Aと同様の操作を行って共重合体Cの粉末を得た。
[Production Example 3]
(Step 1C) Using a flask equipped with two dropping funnels, the monomer was charged into the flask before dropping. That is, in a flask equipped with a nitrogen inlet, a stirrer, a condenser, two dropping funnels and a thermometer, under a nitrogen atmosphere, 88.8 parts of ethyl lactate, 3.1 parts of α-GBLMA, 5.5 parts of ECHMA, 2.3 HAdMA2.3 The temperature of the hot water bath was raised to 80 ° C. while stirring.
(Step 2A ′) The composition of the mixed solution is different from Step 2A in Production Example 1. That is, a mixed solution in which 26.8 parts of α-GBLMA, 30.9 parts of ECHMA, 18.6 parts of HAdMA, 112.5 parts of ethyl lactate, and 1.9 parts of V-601 (product name) were mixed at a constant rate from a dropping funnel for 4 hours. And then dropped into the flask, and then maintained at 80 ° C. for 3 hours.
(Step 2B ′) The composition of the mixed solution is different from Step 2B of Production Example 2. That is, simultaneously with the start of dropping of the mixed solution in Step 2A ′, the mixed solution in which 1.8 parts of ethyl lactate and 0.7 part of V-601 (product name) were mixed was added to the flask over another 0.1 hour from another dropping funnel. It was dripped in and the temperature of 80 degreeC was further hold | maintained for 6.9 hours.
(Step 3A) The same operation as in step 3A of Production Example 1 was performed to obtain a powder of copolymer C.
[製造例4]
(工程1C)製造例3の工程1Cと同様にして、滴下前にフラスコ内に単量体を仕込んだ。
(工程2A”)製造例3の工程2A’とは、乳酸エチルおよびV−601(製品名)の含有量が異なる。すなわち、α−GBLMA26.8部、ECHMA30.9部、HAdMA18.6部、乳酸エチル110.3部、V−601(製品名)0.7部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程2B”)製造例3の工程2B’とは、乳酸エチルおよびV−601(製品名)の含有量が異なる。すなわち、工程2A”の滴下開始と同時に、乳酸エチル4.0部、V−601(製品名)1.4部を混合した混合溶液を別の滴下漏斗より0.1時間かけてフラスコ内に滴下し、さらに80℃の温度を6.9時間保持した。
(工程3A)製造例1の工程3Aと同様の操作を行って共重合体Dの粉末を得た。
[Production Example 4]
(Step 1C) In the same manner as in Step 1C of Production Example 3, a monomer was charged into the flask before dropping.
(Step 2A ″) The content of ethyl lactate and V-601 (product name) is different from Step 2A ′ of Production Example 3. That is, 26.8 parts of α-GBLMA, 30.9 parts of ECHMA, 18.6 parts of HAdMA, A mixed solution in which 110.3 parts of ethyl lactate and 0.7 parts of V-601 (product name) are mixed is dropped into the flask at a constant rate from a dropping funnel over 4 hours, and then maintained at a temperature of 80 ° C. for 3 hours. did.
(Step 2B ″) The contents of ethyl lactate and V-601 (product name) are different from those of Step 2B ′ of Production Example 3. That is, simultaneously with the start of dropping of Step 2A ″, 4.0 parts of ethyl lactate, V A mixed solution in which 1.4 parts of -601 (product name) was mixed was dropped into the flask over another 0.1 hour from another dropping funnel, and the temperature of 80 ° C. was further maintained for 6.9 hours.
(Step 3A) The same operation as in step 3A of Production Example 1 was performed to obtain a powder of copolymer D.
下記の製造例5、6では、極性基を有する単量体としてα−メタクリロイルオキシ−γ−ブチロラクトン(α−GBLMA)、およびメタクリル酸3−ヒドロキシアダマンチル(HAdMA)を用い、酸脱離性基を有する単量体として2−メチル−2−アダマンチルメタクリレート(MAdMA)を用いた。分子設計における構成単位の組成比はα−GBLMA:ECHMA:HAdMA=45:35:20(モル%)とし、重合の手順を変えて、2種の共重合体E、Fを製造した。溶剤および重合開始剤は同じものを使用した。なお、共重合体AとE、DとFは同様の工程により製造している。 In Production Examples 5 and 6 below, α-methacryloyloxy-γ-butyrolactone (α-GBLMA) and 3-hydroxyadamantyl methacrylate (HAdMA) are used as monomers having a polar group, and an acid leaving group is used. 2-Methyl-2-adamantyl methacrylate (MAdMA) was used as the monomer. The composition ratio of the structural units in the molecular design was α-GBLMA: ECHMA: HAdMA = 45: 35: 20 (mol%), and two types of copolymers E and F were produced by changing the polymerization procedure. The same solvent and polymerization initiator were used. Copolymers A and E, D and F are manufactured by the same process.
[製造例5]
(工程1A)窒素導入口、攪拌機、コンデンサー、滴下漏斗及び温度計を備えたフラスコに、窒素雰囲気下で、乳酸エチル76.7部を入れ、攪拌しながら湯浴の温度を80℃に上げた。
(工程2A)α−GBLMA35.6部、MAdMA37.6部、HAdMA18.9部、乳酸エチル138.1部、ジメチル−2,2´−アゾビスイソブチレート(和光純薬工業社製、V−601(製品名))2.8部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程3A)次いで、得られた反応溶液を約7倍量のメタノールと水との混合溶媒(メタノール/水=80/20容量比)に撹拌しながら滴下し、白色のゲル状物の沈殿を得た。得られた沈殿を濾別し、再び約7倍量のメタノールと水との混合溶媒(メタノール/水=9/1容量比)に投入した。これを濾別、回収し、減圧下60℃で約40時間乾燥し、共重合体Eの粉末を得た。
[Production Example 5]
(Step 1A) A flask equipped with a nitrogen inlet, a stirrer, a condenser, a dropping funnel and a thermometer was charged with 76.7 parts of ethyl lactate under a nitrogen atmosphere, and the temperature of the hot water bath was raised to 80 ° C. while stirring. .
(Step 2A) α-GBLMA 35.6 parts, MAdMA 37.6 parts, HAdMA 18.9 parts, ethyl lactate 138.1 parts, dimethyl-2,2′-azobisisobutyrate (manufactured by Wako Pure Chemical Industries, V- A mixed solution in which 2.8 parts of 601 (product name) were mixed was dropped from a dropping funnel into the flask at a constant rate over 4 hours, and then a temperature of 80 ° C. was maintained for 3 hours.
(Step 3A) Next, the obtained reaction solution was added dropwise to a mixed solvent of methanol and water (methanol / water = 80/20 volume ratio) in an amount of about 7 times while stirring to precipitate a white gel. Obtained. The obtained precipitate was separated by filtration and again poured into a mixed solvent of methanol and water in an amount of about 7 times (methanol / water = 9/1 volume ratio). This was filtered and collected, and dried under reduced pressure at 60 ° C. for about 40 hours to obtain a copolymer E powder.
[製造例6]
(工程1C)滴下漏斗を2個備えたフラスコを用い、滴下前にフラスコ内に単量体を仕込んだ。すなわち、窒素導入口、攪拌機、コンデンサー、滴下漏斗2個及び温度計を備えたフラスコに、窒素雰囲気下で、乳酸エチル93.9部、α−GBLMA3.4部、MAdMA6.1部、HAdMA2.0部を入れ、攪拌しながら湯浴の温度を80℃に上げた。
(工程2A”)製造例5の工程2Aとは、混合溶液の組成が異なる。すなわち、α−GBLMA31.1部、MAdMA32.9部、HAdMA16.5部、乳酸エチル116.5部、V−601(製品名)0.6部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程2B”)工程2Aにおける混合溶液の滴下開始と同時に、乳酸エチル4.3部、V−601(製品名)1.4部を混合した混合溶液を別の滴下漏斗より0.1時間かけてフラスコ内に滴下し、さらに80℃の温度を6.9時間保持した。
(工程3A)製造例5の工程3Aと同様の操作を行って共重合体Fの粉末を得た。
[Production Example 6]
(Step 1C) Using a flask equipped with two dropping funnels, the monomer was charged into the flask before dropping. That is, in a flask equipped with a nitrogen inlet, a stirrer, a condenser, two dropping funnels, and a thermometer, 93.9 parts ethyl lactate, 3.4 parts α-GBLMA, 6.1 parts MAdMA, HAdMA 2.0 under a nitrogen atmosphere. The temperature of the hot water bath was raised to 80 ° C. while stirring.
(Step 2A ″) The composition of the mixed solution is different from Step 2A in Production Example 5. That is, 31.1 parts of α-GBLMA, 32.9 parts of MAdMA, 16.5 parts of HAdMA, 116.5 parts of ethyl lactate, V-601 (Product name) A mixed solution in which 0.6 part was mixed was dropped from a dropping funnel into the flask at a constant rate over 4 hours, and then a temperature of 80 ° C was maintained for 3 hours.
(Step 2B ″) Simultaneously with the start of dropping of the mixed solution in Step 2A, a mixed solution obtained by mixing 4.3 parts of ethyl lactate and 1.4 parts of V-601 (product name) was added from another dropping funnel over 0.1 hour. Then, the solution was dropped into the flask, and the temperature of 80 ° C. was further maintained for 6.9 hours.
(Step 3A) The same operation as in step 3A of Production Example 5 was performed to obtain a powder of copolymer F.
下記の製造例7、8では、吸光性基を有する単量体としてベンジルメタクリレート(BzMA)、反応性官能基を有する単量体として2-ヒドロキシエチルメタクリレート(HEMA)、極性基を有する単量体としてα−メタクリロイルオキシ−γ−ブチロラクトン(α−GBLMA)を用いた。分子設計における構成単位の組成比はBzMA:HEMA:α−GBLMA=25:25:50(モル%)とし、重合の手順を変えて、2種の共重合体G、Hを製造した。溶剤および重合開始剤は同じものを使用した。 In the following Production Examples 7 and 8, benzyl methacrylate (BzMA) as a monomer having a light-absorbing group, 2-hydroxyethyl methacrylate (HEMA) as a monomer having a reactive functional group, and a monomer having a polar group Α-methacryloyloxy-γ-butyrolactone (α-GBLMA) was used. The composition ratio of the structural units in the molecular design was BzMA: HEMA: α-GBLMA = 25: 25: 50 (mol%), and the two kinds of copolymers G and H were produced by changing the polymerization procedure. The same solvent and polymerization initiator were used.
[製造例7]
(工程1A)窒素導入口、攪拌機、コンデンサー、滴下漏斗及び温度計を備えたフラスコに、窒素雰囲気下で、プロピレングリコールモノメチルエーテル(PGME)61.9部を入れ、攪拌しながら湯浴の温度を80℃に上げた。
(工程2A)BzMA19.8部、HEMA16.2部、α−GBLMA38.3部、PGME111.5部、ジメチル−2,2´−アゾビスイソブチレート(和光純薬工業社製、V−601(製品名))6.7部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程2G)保持後、反応溶液の50質量%のPGMEをフラスコに投入し、反応溶液を希釈した。
(工程3A)次いで、得られた反応溶液を約4倍量のイソピロピルエーテル(IPE)に撹拌しながら滴下し、白色のゲル状物の沈殿を得た。これを濾別、回収し、減圧下60℃で約40時間乾燥し、共重合体Gの粉末を得た。
[Production Example 7]
(Step 1A) In a flask equipped with a nitrogen inlet, a stirrer, a condenser, a dropping funnel and a thermometer, 61.9 parts of propylene glycol monomethyl ether (PGME) is placed under a nitrogen atmosphere, and the temperature of the hot water bath is adjusted while stirring. Raised to 80 ° C.
(Step 2A) 19.8 parts of BzMA, 16.2 parts of HEMA, 38.3 parts of α-GBLMA, 111.5 parts of PGME, dimethyl-2,2′-azobisisobutyrate (V-601 manufactured by Wako Pure Chemical Industries, Ltd. Product name)) A mixed solution in which 6.7 parts were mixed was dropped from a dropping funnel into the flask at a constant rate over 4 hours, and then a temperature of 80 ° C. was maintained for 3 hours.
(Step 2G) After holding, 50% by mass of PGME of the reaction solution was added to the flask to dilute the reaction solution.
(Step 3A) Next, the obtained reaction solution was added dropwise to about 4 times amount of isopropyl ether (IPE) while stirring to obtain a white gel-like precipitate. This was collected by filtration and dried under reduced pressure at 60 ° C. for about 40 hours to obtain a copolymer G powder.
[製造例8]
(工程1H)窒素導入口、攪拌機、コンデンサー、滴下漏斗2個及び温度計を備えたフラスコに、窒素雰囲気下で、PGME98.3部を入れ、攪拌しながら湯浴の温度を80℃に上げた。
(工程2A”)製造例7の工程2Aとは、混合溶液の組成が異なる。すなわち、BzMA17.8部、HEMA14.6部、α−GBLMA34.5部、PGME67.8部、V−601(製品名)2.1部を混合した混合溶液を滴下漏斗より一定速度で4時間かけてフラスコ中に滴下し、その後、80℃の温度を3時間保持した。
(工程2H)工程2Aにおける混合溶液の滴下開始と同時に、BzMA2.1部、HEMA1.8部、α−GBLMA2.9部、PGME5.9部、V−601(製品名)2.1部を混合した混合溶液を別の滴下漏斗より0.5時間かけてフラスコ内に滴下し、さらに80℃の温度を6.5時間保持した。
(工程2G)保持後、反応溶液の50質量%のPGMEをフラスコに投入し、反応溶液を希釈した。
(工程3A)製造例7の工程3Aと同様の操作を行って共重合体Hの粉末を得た。
[Production Example 8]
(Step 1H) Under a nitrogen atmosphere, 98.3 parts of PGME was placed in a flask equipped with a nitrogen inlet, a stirrer, a condenser, two dropping funnels and a thermometer, and the temperature of the hot water bath was raised to 80 ° C. while stirring. .
(Step 2A ″) The composition of the mixed solution is different from Step 2A of Production Example 7. That is, 17.8 parts of BzMA, 14.6 parts of HEMA, 34.5 parts of α-GBLMA, 67.8 parts of PGME, V-601 (Product) Name) A mixed solution in which 2.1 parts were mixed was dropped from a dropping funnel into the flask at a constant rate over 4 hours, and then a temperature of 80 ° C. was maintained for 3 hours.
(Step 2H) Simultaneously with the start of dropping of the mixed solution in Step 2A, 2.1 parts of BzMA, 1.8 parts of HEMA, 2.9 parts of α-GBLMA, 5.9 parts of PGME, and 2.1 parts of V-601 (product name) are mixed. The mixed solution was dropped into the flask from another dropping funnel over 0.5 hours, and the temperature of 80 ° C. was further maintained for 6.5 hours.
(Step 2G) After holding, 50% by mass of PGME of the reaction solution was added to the flask to dilute the reaction solution.
(Step 3A) A powder of copolymer H was obtained by performing the same operation as in step 3A of Production Example 7.
(レジスト用共重合体の重量平均分子量)
製造例1〜8で得た共重合体A〜Hについて重量平均分子量(Mw)および分子量分布(Mw/Mn)を以下の方法で測定した。
約20mgのサンプルを5mLのTHFに溶解し、0.5μmのメンブランフィルターで濾過して試料溶液を調製し、この試料溶液を東ソー製ゲル・パーミエーション・クロマトグラフィー(GPC)装置:HCL−8220(製品名)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)を求めた。この測定において、分離カラムは、昭和電工社製、Shodex GPC LF−804L(製品名)を3本直列にしたものを用い、溶剤はTHF(テトラヒドロフラン)、流量1.0mL/min、検出器は示差屈折計、測定温度40℃、注入量0.1mLで、標準ポリマーとしてポリスチレンを使用した。測定結果を表1、表3、表5に示す。
(Weight average molecular weight of resist copolymer)
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the copolymers A to H obtained in Production Examples 1 to 8 were measured by the following methods.
About 20 mg of sample was dissolved in 5 mL of THF and filtered through a 0.5 μm membrane filter to prepare a sample solution. This sample solution was prepared by Tosoh gel permeation chromatography (GPC) apparatus: HCL-8220 ( Product name), the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured to obtain the molecular weight distribution (Mw / Mn). In this measurement, the separation column was made by Showa Denko, Shodex GPC LF-804L (product name) in series, the solvent was THF (tetrahydrofuran), the flow rate was 1.0 mL / min, and the detector was a differential. Polystyrene was used as a standard polymer with a refractometer, a measurement temperature of 40 ° C., and an injection amount of 0.1 mL. The measurement results are shown in Table 1, Table 3, and Table 5.
(レジスト用共重合体における構成単位の組成比)
レジスト用共重合体における、各単量体に由来する各構成単位の組成比(単位:モル%)を、1H−NMRの測定により求めた。
この測定において、日本電子(株)製、JNM−GX270型 超伝導FT−NMRを用い、約5質量%のサンプル溶液(溶媒は重水素化ジメチルスルホキシド(A〜F)、重水素化クロロホルム(G、H))を直径5mmφのサンプル管に入れ、観測周波数270MHz、シングルパルスモードにて、1H 64回の積算を行った。測定温度は測定溶媒が重水素化ジメチルスルホキシドの場合は60℃、重水素化クロロホルムの場合は40℃で行った。測定結果を表1、表3、表5に示す。
(Composition ratio of structural units in resist copolymer)
The composition ratio (unit: mol%) of each structural unit derived from each monomer in the resist copolymer was determined by 1 H-NMR measurement.
In this measurement, a JNM-GX270 type superconducting FT-NMR manufactured by JEOL Ltd. was used, and a sample solution of about 5% by mass (solvents were deuterated dimethyl sulfoxide (A to F), deuterated chloroform (G , H)) was put into a sample tube having a diameter of 5 mmφ, and 1 H was integrated 64 times in an observation frequency of 270 MHz and a single pulse mode. The measurement temperature was 60 ° C. when the measurement solvent was deuterated dimethyl sulfoxide, and 40 ° C. when deuterated chloroform was used. The measurement results are shown in Table 1, Table 3, and Table 5.
(粒径分布測定による評価)
製造例1〜6で得た重合体A〜Fに関して、共重合体濃度が20質量%PGMEA(プロピレングリコールモノメチルエーテルアセテート)溶液を調整後十分に撹拌を行い、均一な試験溶液を得た。この試験溶液を0.5μmのフィルター(有機溶媒用)で濾過した後、25.0℃において、動的光散乱測定を行った。得られる粒径分布から、最大の散乱強度を示す粒径Rにおける散乱強度(S0)を求めた。
続いて、該試験溶液に、該試験溶液に対してm質量%の貧溶媒(ヘプタン)を添加し、十分に撹拌を行い、動的光散乱測定を行った。得られる粒径分布から、貧溶媒無添加時に最大の散乱強度を示した粒径Rにおける散乱強度Smを求めた。さらに、粒径Rにおける散乱強度の、貧溶媒添加による減少を示すSm/S0を求めた。
20%<Sm/S0<70%の範囲で、貧溶媒添加量mを8点取って測定を行い、得られたデータから、Sm/S0=50%となる貧溶媒添加量(濃度)を求め、M(質量%)を求めた。
製造例7、8で得た重合体G、Hに関しては、溶媒にTHF(テトラヒドロフラン)、貧溶媒にIPE(イソプロピルエーテル)を用いた。
結果を表2、表4、表6に示す。
(Evaluation by particle size distribution measurement)
With respect to the polymers A to F obtained in Production Examples 1 to 6, the copolymer concentration was adjusted to 20 mass% PGMEA (propylene glycol monomethyl ether acetate), and then sufficiently stirred to obtain a uniform test solution. The test solution was filtered through a 0.5 μm filter (for organic solvent), and then dynamic light scattering measurement was performed at 25.0 ° C. From the obtained particle size distribution, the scattering intensity (S 0 ) at the particle diameter R showing the maximum scattering intensity was determined.
Subsequently, to the test solution, m% by mass of a poor solvent (heptane) was added to the test solution, and the mixture was sufficiently stirred to perform dynamic light scattering measurement. From the obtained particle size distribution, the scattering intensity S m at the particle diameter R that showed the maximum scattering intensity when no poor solvent was added was determined. Furthermore, to determine the S m / S 0 shown in scattering intensity in particle diameter R, the reduction with a poor solvent addition.
In the range of 20% <S m / S 0 <70%, the poor solvent addition amount m was measured by taking 8 points, and from the obtained data, the poor solvent addition amount (S m / S 0 = 50%) ( Density | concentration) was calculated | required and M (mass%) was calculated | required.
Regarding the polymers G and H obtained in Production Examples 7 and 8, THF (tetrahydrofuran) was used as a solvent and IPE (isopropyl ether) was used as a poor solvent.
The results are shown in Table 2, Table 4, and Table 6.
(曇点評価)
製造例1〜6で得た重合体A〜Fに関して、20質量%PGMEA(プロピレングリコールモノメチルエーテルアセテート)溶液を調整後十分に撹拌を行い、均一な試験溶液を得た。この試験溶液を撹拌しながら、(25.0℃において)貧溶媒(ヘプタン)を波長450nmにおける透過率が85±3%となるまで添加し、この時点(曇点)までの貧溶媒添加量(質量%)を求めた。
製造例7、8で得た重合体G、Hに関しては、溶媒にTHF(テトラヒドロフラン)、貧溶媒にIPE(イソプロピルエーテル)を用いた。
結果を表2、表4、表6に示す。
(Cloud point evaluation)
Regarding the polymers A to F obtained in Production Examples 1 to 6, a 20% by mass PGMEA (propylene glycol monomethyl ether acetate) solution was prepared and sufficiently stirred to obtain a uniform test solution. While stirring this test solution, a poor solvent (heptane) was added (at 25.0 ° C.) until the transmittance at a wavelength of 450 nm was 85 ± 3%, and the amount of poor solvent added up to this point (cloud point) ( Mass%).
Regarding the polymers G and H obtained in Production Examples 7 and 8, THF (tetrahydrofuran) was used as a solvent and IPE (isopropyl ether) was used as a poor solvent.
The results are shown in Table 2, Table 4, and Table 6.
(感度評価]
上記レジスト用共重合体A〜Fをそれぞれ用いてリソグラフィー用のレジスト組成物を調製し、これを用いてドライリソグラフィーを行ったときの感度を以下の方法で測定した。
(レジスト組成物の調製)
下記の配合成分を混合してレジスト組成物を得た。
レジスト用共重合体:10部、
光酸発生剤(みどり化学(株)社製、製品名:TPS−105、トリフェニルスルホニウムトリフレート):0.2部、
レベリング剤(日本ユニカー(株)社製、製品名:L−7001):0.2部、
溶媒(PGMEA):90部。
(Sensitivity evaluation)
Resist compositions for lithography were prepared using the resist copolymers A to F, respectively, and the sensitivity when dry lithography was performed using the resist compositions was measured by the following method.
(Preparation of resist composition)
The following compounding components were mixed to obtain a resist composition.
Copolymer for resist: 10 parts,
Photoacid generator (manufactured by Midori Chemical Co., Ltd., product name: TPS-105, triphenylsulfonium triflate): 0.2 part,
Leveling agent (Nihon Unicar Co., Ltd., product name: L-7001): 0.2 parts,
Solvent (PGMEA): 90 parts.
(ドライリソグラフィー)
上記で得たレジスト組成物を、6インチシリコンウエハー上に回転塗布し、ホットプレート上で120℃、60秒間プリベーク(PB)して、厚さ300nmの薄膜を形成した。ArFエキシマレーザー露光装置(リソテックジャパン社製、製品名:VUVES−4500)を用い、露光量を変えて18ショットの露光を行った。1ショットは10mm×10mmの矩形領域に対する全面露光である。次いで110℃、60秒間のポストベーク(PEB)を行った後、レジスト現像アナライザー(リソテックジャパン社製、製品名:RDA−790)を用い、23.5℃にて2.38%水酸化テトラメチルアンモニウム水溶液で65秒間現像し、現像中のレジスト膜厚の経時変化を測定した。各露光量ごとに、初期膜厚に対する、60秒間現像した時点での残存膜厚の割合(以下、残膜率という。単位:%)を求めた。
(Dry lithography)
The resist composition obtained above was spin-coated on a 6-inch silicon wafer and pre-baked (PB) at 120 ° C. for 60 seconds on a hot plate to form a thin film having a thickness of 300 nm. Using an ArF excimer laser exposure apparatus (manufactured by RISOTEC Japan, product name: VUVES-4500), exposure was changed for 18 shots. One shot is the entire surface exposure for a rectangular area of 10 mm × 10 mm. Next, after post-baking (PEB) at 110 ° C. for 60 seconds, using a resist development analyzer (product name: RDA-790, manufactured by RISOTEC Japan), 2.38% tetrahydroxide at 23.5 ° C. Development was carried out with a methylammonium aqueous solution for 65 seconds, and the change over time in the resist film thickness during development was measured. For each exposure amount, the ratio of the remaining film thickness at the time of development for 60 seconds with respect to the initial film thickness (hereinafter referred to as the remaining film ratio, unit:%) was determined.
得られたデータを基に、露光量(mJ/cm2 )の対数と、初期膜厚に対する60秒間現像した時点での残存膜厚率(以下、残膜率という)(%)をプロットした曲線(以下、露光量残膜率曲線という)を作成し、露光量残膜率曲線が残膜率0%と交わる露光量(mJ/cm2)(以下、Ethという)の値を求めた。Ethとは、残膜率0%とするための必要露光量であり、感度を表す。Ethが小さいほど感度が高い。結果を、表2、表4に示す。 A curve plotting the logarithm of the exposure amount (mJ / cm 2 ) and the residual film thickness ratio (hereinafter referred to as the residual film ratio) (%) when developed for 60 seconds with respect to the initial film thickness, based on the obtained data (Hereinafter referred to as exposure amount remaining film rate curve) was prepared, and the value of exposure amount (mJ / cm 2 ) (hereinafter referred to as Eth) at which the exposure amount remaining film rate curve intersected with the remaining film rate 0% was determined. Eth is a necessary exposure amount for achieving a remaining film ratio of 0% and represents sensitivity. The smaller the Eth, the higher the sensitivity. The results are shown in Tables 2 and 4.
[溶解性評価]
上記リソグラフィー用共重合体G、Hをそれぞれ用いて溶解性評価用の溶液を調製し、溶液の温度は常温(25℃)とした。紫外可視分光光度計として、島津製作所社製、UV−3100PC(製品名)を用い、光路長10mmの石英製角型セルに測定用溶液を入れ、波長450nmにおける透過率を測定する方法で、溶解性評価を行った。該透過率が高いほど溶解性が良好であり、基材上に塗膜した際の面内におけるリソグラフィー性能のばらつき低減に結びつく。
(溶解性評価用の溶液調製)
下記の配合成分を混合して評価用溶液を得た。
リソグラフィー用共重合体:20部、
溶媒1(THF):80部、
溶媒2(IPE):8部。
[Solubility evaluation]
A solution for solubility evaluation was prepared using each of the above copolymers G and H for lithography, and the temperature of the solution was room temperature (25 ° C.). Using UV-3100PC (product name) manufactured by Shimadzu Corporation as an ultraviolet-visible spectrophotometer, the measurement solution is put into a quartz square cell having an optical path length of 10 mm, and the transmittance at a wavelength of 450 nm is measured. Sex evaluation was performed. The higher the transmittance, the better the solubility, leading to a reduction in lithographic performance variation in the surface when the film is coated on the substrate.
(Solution preparation for solubility evaluation)
The following formulation components were mixed to obtain an evaluation solution.
Lithographic copolymer: 20 parts,
Solvent 1 (THF): 80 parts
Solvent 2 (IPE): 8 parts.
下記表1に重合体A〜Dの物性を示す。 Table 1 below shows the physical properties of the polymers A to D.
[実施例1〜4]
重合体A〜Dの粒径分布測定による評価結果(貧溶媒添加量)、曇点評価結果(曇点に到達するまでの貧溶媒添加量)を下記表2に示す。
[Examples 1 to 4]
Table 2 below shows the evaluation results (poor solvent addition amount) and the cloud point evaluation results (poor solvent addition amount until reaching the cloud point) by measuring the particle size distribution of the polymers A to D.
下記表3に重合体E、Fの物性を示す。 Table 3 below shows the physical properties of the polymers E and F.
[実施例5、6]
重合体E、Fの粒径分布測定による評価結果(M値:貧溶媒添加量)、曇点評価結果(曇点に到達するまでの貧溶媒添加量)を下記表4に示す。
[Examples 5 and 6]
The evaluation results (M value: poor solvent addition amount) and the cloud point evaluation results (poor solvent addition amount until reaching the cloud point) by the particle size distribution measurement of the polymers E and F are shown in Table 4 below.
下記表3に重合体E、Fの物性を示す。 Table 3 below shows the physical properties of the polymers E and F.
[実施例7、8]
重合体G、Hの粒径分布測定による評価結果(M値:貧溶媒添加量)、曇点評価結果(曇点に到達するまでの貧溶媒添加量)を下記表6に示す。
[Examples 7 and 8]
Table 6 below shows evaluation results (M value: poor solvent addition amount) and cloud point evaluation results (poor solvent addition amount until reaching the cloud point) of the polymers G and H by particle size distribution measurement.
表1に示すとおり、上記共重合体A〜Dは、ほぼ同等の組成・分子量の共重合体であるが、重合方法が異なる共重合体同士である。これらは重合方法の違いにより、共重合体における組成比の均一性等に差異を有する。
同様に、表3に示すとおり、上記共重合体E及びFは、ほぼ同等の組成・分子量共重合体であるが、重合方法が異なる共重合体同士である。これらは重合方法の違いにより、共重合体における組成比の均一性等に差異を有する。
同様に、表5に示すとおり、上記共重合体G及びHは、ほぼ同等の組成・分子量の共重合体であるが、重合方法が異なる共重合体同士である。これらは重合方法の違いにより、共重合体における組成比の均一性等に差異を有する。
なお、上記粒径分布測定による評価や曇点評価では、貧溶媒の添加量が多いほど、共重合体における組成比が均一性等を有することを示す。
上記表2、表4及び表6に示すとおり、上記共重合体同士の比較において、これらの本発明の方法の粒径分布測定による評価結果(貧溶媒添加量)、曇点評価結果(曇点に到達するまでの貧溶媒添加量)は、現像欠陥やLERと関連性のあるEth、または溶解性に関連のある透過率に相関関係が示され、間接的にリソグラフィー特性を評価することができることを確認した。
これらの結果より、本発明の方法は、高精度で、リソグラフィー特性の間接的な評価ができることが確認された。
As shown in Table 1, the copolymers A to D are copolymers having substantially the same composition and molecular weight, but are copolymers having different polymerization methods. These have differences in the uniformity of the composition ratio in the copolymer due to the difference in the polymerization method.
Similarly, as shown in Table 3, the above-mentioned copolymers E and F are substantially the same composition / molecular weight copolymers, but are copolymers having different polymerization methods. These have differences in the uniformity of the composition ratio in the copolymer due to the difference in the polymerization method.
Similarly, as shown in Table 5, the copolymers G and H are copolymers having substantially the same composition and molecular weight, but are copolymers having different polymerization methods. These have differences in the uniformity of the composition ratio in the copolymer due to the difference in the polymerization method.
In addition, in the evaluation by the particle size distribution measurement or the cloud point evaluation, it is shown that the composition ratio in the copolymer has uniformity and the like as the addition amount of the poor solvent increases.
As shown in Table 2, Table 4 and Table 6, in comparison between the copolymers, evaluation results (poor solvent addition amount), cloud point evaluation results (cloud point) of these methods of the present invention. (The amount of poor solvent added until reaching) is correlated with development defects, Eth related to LER, or transmittance related to solubility, and can indirectly evaluate lithography properties It was confirmed.
From these results, it was confirmed that the method of the present invention can indirectly evaluate the lithography characteristics with high accuracy.
Claims (1)
(1)リソグラフィー用共重合体を溶媒に溶解させて試験溶液を調製する工程;
(2)動的光散乱法を用いて、前記試験溶液の粒径分布における散乱強度を測定する工程;
(3)前記試験溶液に貧溶媒を添加し、動的光散乱法を用いて、前記貧溶媒添加後の試験溶液の粒径分布における散乱強度を測定する工程;
(4)前記(2)工程において測定される、粒径分布の任意のピーク(a)の散乱強度を基準とした場合に、貧溶媒の添加により、前記(3)工程において測定される、前記ピーク(a)の散乱強度が、前記基準に対して所定の強度に減少するまでに要する貧溶媒添加量を求める工程;
(5)前記貧溶媒添加量の差異により、前記リソグラフィー用共重合体を含む組成物のリソグラフィー特性を評価する工程。 Lithographic copolymer evaluation method comprising the following steps:
(1) a step of preparing a test solution by dissolving a copolymer for lithography in a solvent;
(2) a step of measuring the scattering intensity in the particle size distribution of the test solution using a dynamic light scattering method;
(3) adding a poor solvent to the test solution and measuring a scattering intensity in a particle size distribution of the test solution after the poor solvent is added using a dynamic light scattering method;
(4) When the scattering intensity of an arbitrary peak (a) of the particle size distribution measured in the step (2) is used as a reference, the measurement is performed in the step (3) by adding a poor solvent. Obtaining a poor solvent addition amount required for the scattering intensity of the peak (a) to decrease to a predetermined intensity with respect to the reference;
(5) The process of evaluating the lithography characteristic of the composition containing the said copolymer for lithography by the difference in the said poor solvent addition amount.
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