JP2005326174A - Method for analyzing distribution of copolymer composition of copolymer for resist - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for analyzing the distribution of a copolymer composition of a copolymer for a resist rapidly, simply and accurately in DUV excimer laser lithography or electron beam lithography. <P>SOLUTION: In the method for analyzing the copolymer composition of the copolymer containing constituent units (A) and (B) using a liquid phase chromatography apparatus, liquid phase chromatography is performed under a preliminarily calculated condition of a combination (condition A) of an elute composition, with which the top point of the elution curve measured by a liquid phase chromatography method of a homopolymer different in the molecular weight of the constituted unit (A) coincides, and the temperature of a column or a combination (condition B) of an elute composition, with which the top point of the elution curve measured by the liquid phase chromatography method of the homopolymer different in the molecular weight of the constituent unit (B) and, on the basis of the obtained elution curve, the composition of a binary copolymer is analyzed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for analyzing a copolymer composition distribution of a resist copolymer, and more particularly to a method for analyzing a copolymer composition distribution of a chemically amplified resist copolymer suitable for fine processing using an excimer laser or an electron beam. .

In the analysis of polymers using high performance liquid phase chromatography (HPLC), a method of eluting the polymers in descending order of molecular weight by JCMoore in 1964, the so-called size exclusion chromatography (SEC) method was first introduced in Reference 1. First of all, adsorption chromatography (AC) method in which the same polar polymer is eluted in ascending order of molecular weight by changing the interaction between the polymer and the stationary phase in the separation column by Teramachi et al. Was introduced in Document 2. In the late 1980s, by preparing conditions such as the separation column, eluent, and measurement temperature, the elution behavior between the SEC method and the AC method described above, that is, the criticality where the sample appears in almost the same elution volume regardless of the molecular weight. A critical adsorption chromatography (LC-CAP) method using a critical adsorption point (CAP) was introduced in References 3 and 4 by Gorshokov et al. Examples of polymer analysis using this LC-CAP method include copolymer composition distributions of styrene-methyl methacrylate block copolymers by Pasch et al. (References 5 and 6), and methacrylic acid (monomethoxy by Murgasova et al.). Polyethylene glycol) -styrene graft copolymer copolymer composition distribution, the number of branches (Document 7), and the like are known.
On the other hand, with the recent miniaturization of patterns, it has become necessary to control the primary structure of the resin used for resist, especially the copolymer composition distribution, in order to satisfy various lithography performances. Establishment is required. However, at present, no method has been reported for analyzing the copolymer composition distribution of the resist copolymer quickly, simply and accurately.
JC Moore, J. Polym. Sci., A2, 835 (1964) S. Teramachi, A. Hasegawa, Y. Shima, M. Akatsuka and M. Nakajima, Macromolecules, 12, 992 (1979) AV Grorshkov and AM Skvortsov, Vyscomol.Soedin, A30, 453 (1988) SG Entelis, VV Evreinov and AV Grorshkov, Adv.Polym.Sce., 76, 129 (1986) H. Pasch, C. Brinkamann and Y. Gallot, Polymer, 34, 4099 (1993) H. Pasch, Y. Gallot and B. Trathnigg, Polymer, 34, 4986 (1993) R. Murgasova, I. Capek, E. Lathova, D. Berek and S. Florian, Eur. Polym. J., 34, 659 (1998)

  An object of the present invention is to provide a method for analyzing a copolymer composition distribution of a resist copolymer quickly, simply and accurately in DUV excimer laser lithography or electron beam lithography.

The inventors of the present invention diligently studied to achieve the above object, and in particular, focused on the copolymer chain structure and distribution of the resist copolymer, and as a result, analyzed the copolymer composition distribution quickly, simply, and accurately. The method has been found and the present invention has been completed.
That is, the first gist of the present invention is a method for analyzing the copolymer composition distribution of a resist copolymer, characterized by using a critical adsorption chromatography method.

The second gist of the present invention is a method for analyzing a copolymer composition of a copolymer containing the structural units (A) and (B) using a liquid phase chromatography apparatus, wherein the structural unit ( A combination of the eluent composition and the column temperature at which the top points of the elution curves measured by the liquid phase chromatography method of homopolymers having different molecular weights in A) coincide with each other (condition A), or the structural unit (B) Obtain either one of the combinations of eluent composition and column temperature (condition B) with which the top points of the elution curves measured by liquid phase chromatography of homopolymers having different molecular weights match, This is a method for analyzing the copolymer composition of a resist copolymer, in which liquid phase chromatography is performed and the composition of the binary copolymer is analyzed based on the obtained elution curve.
The third gist of the present invention is a method for analyzing a copolymer composition of a copolymer containing the structural units (A) and (B) using a liquid phase chromatography apparatus, wherein the structural unit (A) Combination of eluent composition and column temperature at which the top points of elution curves measured by liquid phase chromatography of homopolymers having different molecular weights coincide (condition A), elution time A, and the constitution Obtaining a combination of eluent composition and column temperature (condition B), and elution time B in which the top points of elution curves measured by liquid phase chromatography of homopolymers having different molecular weights of unit (B) coincide. Compare elution time A and elution time B,
When elution time A <elution time B, the condition for starting liquid phase chromatography is condition A, and the eluent composition is changed so that the condition for ending is condition B.
When elution time B <elution time A, the condition for starting liquid phase chromatography is condition B, and the eluent composition and column temperature are changed so that the condition for ending is condition A. Carried out,
This is a method for analyzing the copolymer composition of a copolymer for resist, in which the composition of the binary copolymer is analyzed based on the obtained elution curve.
The fourth gist of the present invention is an analysis of the copolymer composition distribution of the resist copolymer of the previous period in which the structural unit having a lactone skeleton is selected from the group consisting of the following formulas (1-1) to (1-2). Is the method.

（式（１−１）中、Ｒ¹¹は水素原子またはメチル基を表し、Ｒ¹、Ｒ²はそれぞれ独立に水素原子、炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基または炭素数１〜６のアルコールでエステル化されたカルボキシ基を表し、Ａ¹、Ａ²はそれぞれ独立に水素原子、炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基または炭素数１〜６のアルコールでエステル化されたカルボキシ基を表すか、あるいは、Ａ¹とＡ²とが一緒になって−Ｏ−、−Ｓ−、−ＮＨ−または炭素数１〜６のメチレン鎖［−（ＣＨ₂）_k−（ｋは１〜６の整数を表す）］を表す。Ｘ¹は、置換基としてヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコールでエステル化されたカルボキシ基、シアノ基およびアミノ基からなる群より選ばれる少なくとも一つの基を有していてもよい炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基、シアノ基またはアミノ基を表し、ｎ１は０〜４の整数を表す。なお、ｎ１が２以上の場合にはＸ¹として複数の異なる基を有することも含む。
式（１−２）中、Ｒ¹²は水素原子またはメチル基を表し、Ｒ³、Ｒ⁴はそれぞれ独立に水素原子、炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基または炭素数１〜６のアルコールでエステル化されたカルボキシ基を表し、Ａ³、Ａ⁴はそれぞれ独立に水素原子、炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基または炭素数１〜６のアルコールでエステル化されたカルボキシ基を表すか、あるいは、Ａ³とＡ⁴とが一緒になって−Ｏ−、−Ｓ−、−ＮＨ−または炭素数１〜６のメチレン鎖［−（ＣＨ₂）_l−（ｌは１〜６の整数を表す）］を表す。Ｘ²は、置換基としてヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコールでエステル化されたカルボキシ基、シアノ基およびアミノ基からなる群より選ばれる少なくとも一つの基を有していてもよい炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基、シアノ基またはアミノ基を表し、ｎ２は０〜４の整数を表す。なお、ｎ２が２以上の場合にはＸ²として複数の異なる基を有することも含む。）
本発明の第五の要旨は、酸脱離性基を有する構成単位が、下記式（２−１）である前記のレジスト用共重合体の共重合組成分布の分析方法である。

(In formula (1-1), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹ and R ² are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, and a carboxy group. Or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, wherein A ¹ and A ² are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carbon atom. Represents a carboxy group esterified with an alcohol having a number of 1 to 6, or A ¹ and A ² together represent —O—, —S—, —NH—, or a methylene chain having 1 to 6 carbon atoms; [— (CH ₂ ) _k — (k represents an integer of 1 to 6)] X ¹ is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, or a carbon number of 1 to 6 as a substituent. A carboxy group esterified with an alcohol A linear or branched alkyl group having 1 to 6 carbon atoms which may have at least one group selected from the group consisting of an ano group and an amino group, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, Represents an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, a cyano group, or an amino group, and n1 represents an integer of 0 to 4. When n1 is 2 or more Includes a plurality of different groups as X ¹ .
In Formula (1-2), R ¹² represents a hydrogen atom or a methyl group, and R ³ and R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or Represents a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and A ³ and A ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carbon number. Represents a carboxy group esterified with an alcohol of 1 to 6, or A ³ and A ⁴ together form —O—, —S—, —NH— or a methylene chain having 1 to 6 carbon atoms [ - (CH _{2) l} - represents a (l is an integer of 1-6)]. X ² is at least one selected from the group consisting of a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, a cyano group, and an amino group as a substituent. C1-C6 linear or branched alkyl group which may have one group, a hydroxy group, a carboxy group, a C1-C6 acyl group, a C1-C6 alkoxy group, C1-C1 6 represents a carboxy group, a cyano group or an amino group esterified with an alcohol of 6, and n2 represents an integer of 0 to 4. Incidentally, also includes having a plurality of different groups as X ² in the case of n2 is 2 or more. )
The fifth gist of the present invention is a method for analyzing a copolymer composition distribution of the copolymer for resist, wherein the structural unit having an acid leaving group is the following formula (2-1).

（式（２−１）中、Ｒ^３１は水素原子またはメチル基を表し、Ｒ¹は炭素数１〜３のアルキル基を表し、Ｘ¹は、置換基としてヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコールでエステル化されたカルボキシ基およびアミノ基からなる群より選ばれる少なくとも一つの基を有していてもよい炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基またはアミノ基を表し、ｎ１は０〜４の整数を表す。なお、ｎ１が２以上の場合にはＸ¹として複数の異なる基を有することも含む。）

(In the formula ^{(2-1), R 31} represents a hydrogen atom or a methyl group, R ¹ represents an alkyl group having 1 to 3 carbon atoms, X ¹ is hydroxy group as a substituent, a carboxy group, a carbon number 1 A straight chain or branched chain having 1 to 6 carbon atoms, which may have at least one group selected from the group consisting of an acyl group of -6, a carboxy group esterified with an alcohol having 1 to 6 carbons, and an amino group An alkyl group, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group or an amino group esterified with an alcohol having 1 to 6 carbon atoms, and n1 is 0 Represents an integer of ˜4, and when n1 is 2 or more, X ¹ includes a plurality of different groups.

  By the method for analyzing the copolymer composition distribution of the resist copolymer of the present invention, the copolymer composition distribution can be analyzed quickly, simply and accurately.

The analysis method of the copolymer composition distribution of the resist copolymer using the critical adsorption chromatography method of the present invention is based on a liquid phase chromatography (LC) method, and a commercially available LC apparatus can be used.
In the critical adsorption chromatography method, a mixture of a good solvent and a poor solvent (eluent) of a copolymer as a sample is used as a moving layer, inorganic and organic gels are used as a fixed layer, a sample, a gel, a sample, and an eluent In this method, the components are separated and detected by the polar distribution of one polymer chain of the copolymer as a sample, that is, the copolymer composition distribution, utilizing the interaction generated between the two. The eluent serving as the moving layer is pressure-fed at a constant flow rate by a constant-rate liquid feed pump. Inorganic and organic gels, which are fixed layers, are packed in a (analytical) column and used. A typical LC system consists of an eluent tank, a pump, a switching valve, a sampling loop, a switching valve, a guard column, an analytical column, a detector, and a waste liquid tank in the order in which the eluent flows. ing.

  A resist copolymer to be measured for the copolymer composition distribution is dissolved in a solvent in which the copolymer is completely dissolved to prepare a sample. The solvent to be used is not particularly limited as long as it is a good solvent for the resist copolymer or a mixed solvent in which the resist copolymer is completely dissolved in a mixture of the good solvent and the poor solvent. For example, water, methanol, ethanol , Alcohol solvents such as isopropanol, chlorine solvents such as carbon tetrachloride, chloroform, methylene chloride, chlorobenzene and dichlorobenzene, nitrile solvents such as acetonitrile, hydrocarbon solvents such as hexane, heptane and cyclohexane, benzene, toluene, Aromatic solvents such as xylene, acetate solvents such as ethyl acetate and butyl acetate, ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as diethyl ether, diisopropyl ether, 1,4-dioxane, tetrahydrofuran, N, N-dimethyl Formamide, N, N-amide solvent such as dimethylacetamide, sulfo solvents such as dimethyl sulfoxide, nitrogen-containing aromatic solvents such as pyridine, can be used weakly acidic solvent such as acetic acid. These solvents may be deuterated. Further, when preparing the sample, the resist copolymer may be dissolved after being dried in solid form, or the polymer solution after polymerization may be diluted with the above-mentioned solvent. The concentration of the sample is usually 0.05 to 10 mg / mL, preferably 0.1 to 5 mg / mL. If the sample concentration is too low, the detection sensitivity will decrease and the analysis accuracy will decrease, or the sample will be difficult to prepare.If the sample concentration is too high, the signal will exceed the measurement limit of the detector. This is not preferable because the analysis accuracy is lowered due to the excessively high value. The amount of the sample injected into the LC device is usually 5 to 200 μL, preferably 10 to 100 μL. If the amount of sample is too small, there will be a problem that the detection sensitivity will decrease or the accuracy of sample injection will decrease and the analysis accuracy will decrease.If the amount of sample is too large, the signal will exceed the measurement limit of the detector. This is not preferable because the analysis accuracy is lowered due to the excessively high value. The amount of the sample can be set to a desired amount by the LC apparatus.

  The eluent used as the moving layer separates the copolymer composed of two or more kinds of structural units having different polarities according to the chemical composition ratio. It is necessary to use it. Therefore, a good solvent of the resist copolymer to be measured for the copolymer composition distribution or a mixed solvent in which the resist copolymer is completely dissolved in a mixture of the good solvent and the poor solvent is used. The same solvent as that used for preparing the mixture is used, but the mixing composition ratio is not particularly limited when mixed and used. The eluent is usually sent by a metering pump at a flow rate of 0.1 to 2.0 mL / min, preferably 0.2 to 1.0 mL / min. If the flow rate is small, the analysis time becomes long, and if the flow rate is large, the analysis accuracy decreases, which is not preferable. The liquid feeding accuracy of the metering liquid pump is usually within about ± 1.0% to about ± 0.5%. In addition, since the eluent used is a mixture of two or more types of solvents, a quantitative liquid feeding pump capable of mixing two or more types of solvents at an arbitrary ratio or changing the mixing ratio with time. Two or more units are preferably provided. Moreover, in order to mix two or more types of solvents uniformly, it is preferable to provide a mixing column between the metering liquid pump and the switching valve. Furthermore, it is preferable to provide a deaeration device between the eluent tank and the metered liquid feed pump because minute bubbles present in the eluent are removed and the liquid feed speed is stabilized.

The eluent sent out by the fixed liquid feed pump is sent to the analytical column, but there is a sample injection mechanism in front of the analytical column. The sample injection mechanism has a configuration of switching valve + sampling loop + switching valve. The sampling loop is a part for temporarily storing the sample. In a state where the eluent constantly flows, the eluent is sent to the analytical column without passing through the sampling loop. At the time of sample injection, a switching valve provided on both sides of the sampling loop is switched to the sample side, so that the sample in the sampling loop is sent to the analytical column.
In the method for analyzing a copolymer composition distribution of the present invention, the capacity of the sampling loop is usually 10 to 200 μL, preferably 10 to 50 μL. The sampling loop capacity is set by replacing the sampling loop with a desired capacity. For example, 10, 20, 50, 100 and 200 μL sampling loops are commercially available from Tosoh Corporation. The volume of the sampling loop to be used is determined by a ratio to the amount of sample (here, sampling loop volume / sample amount = sampling loop volume ratio). The sampling loop capacity ratio is usually 1 to 10, preferably 1 to 5, and particularly preferably 1 to 3. When the amount of sample, the volume of the sampling loop, and the volume ratio of the sampling loop are within the above ranges, the volume balance is excellent and the analysis accuracy of the copolymer composition distribution of the resist copolymer is good.
A guard column is disposed between the analysis column and the sample injection mechanism as necessary. The guard column is, for example, for removing unnecessary components and foreign matters in the eluent in the sample and preventing the analysis column from deteriorating.

As the fixed layer, an inorganic or organic gel is packed in a column (in the present invention, also referred to as “analysis column” in order to be distinguished from the guard column). The total length of the analytical column is usually 10 to 50 cm, more preferably 10 to 40 cm. For example, when one 15 cm column is used, it is preferably 1 to 3 in series, particularly preferably one. The inner diameter of the column is not particularly limited, but is usually 7 mm or less, preferably 5 mm or less. The inorganic or organic gel can be selected according to the polarity of the sample to be measured, such as silica gel, polyvinyl alcohol gel, polyhydroxyacrylate gel, polyacrylate gel, polystyrene-divinylbenzene gel, alumina, and carbon. Moreover, you may use what gave the chemical modification with a C4-C18 alkyl chain, a phenyl group, a cyano group, an amino group, a sulfo group, diol, a glyceropropyl group, etc. with respect to said stationary phase. . Among these, silica gel, polyacrylate gel, and polystyrene-divinylbenzene gel chemically modified with an alkyl chain having 4 to 18 carbon atoms are preferable from the viewpoint that the analysis accuracy of the copolymer composition distribution of the resist copolymer is good.
The inorganic or organic gel is in the form of particles, but the particle size is usually 20 μm or less, preferably 10 μm or less. The particle size is a value in a tetrahydrofuran (hereinafter sometimes referred to as THF) solvent because the degree of swelling varies depending on the type of eluent. Inorganic or organic gels having such particle sizes are commercially available from liquid phase chromatography equipment companies and the like.

By using the above inorganic or organic gel as a filler over the entire length of the analytical column, the balance of the interaction between the inorganic or organic gel and the resist copolymer is improved, the analytical accuracy is good, and the time required is short. It is possible to analyze the copolymer composition distribution.
Since the sample flowing out from the analytical column is separated by the polarity of one polymer chain of the copolymer, the proportion of each copolymer composition fraction component is detected by detecting this with an appropriate detector. it can. As detectors, UV / Vis absorbance (UV-Vis) detector, fluorescence detector, differential refractive index (RI) detector, multi-wavelength detector, conductivity detector, electrochemical detector, evaporative light scattering detection (ELSD), mass spectrometer (MSD), nuclear magnetic resonance (NMR) apparatus, infrared (IR) spectrophotometer and the like. Among them, ELSD is preferable because it can be used even when the eluent has low light transmittance in the ultraviolet light and visible light regions. Also, NMR is preferred because the copolymer composition can be determined directly. A data processor is connected to the detector, and the copolymer composition distribution is quantified by a method described later, usually using a computer or the like.
The analytical column and preferably the detector are placed in a constant temperature bath and maintained at a constant temperature. This is to eliminate disturbance of measurement accuracy when measuring molecular weight as much as possible and improve analysis accuracy. The column is usually maintained at a temperature slightly higher than room temperature to room temperature, and the temperature control accuracy is preferably ± 0.2 ° C. or less, particularly preferably ± 0.1 ° C. or less.

Next, a method for analyzing the composition distribution of a copolymer using the critical adsorption chromatography method of the present invention will be described. Here, for simplicity, a copolymer UT composed of two types of structural units u and t will be described. explain.
First, polymers (hereinafter referred to as homopolymers) U and T having only three structural units having three or more different mass average molecular weights are prepared. The method for producing the homopolymer is not particularly limited, such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization. However, since the molecular weight control is easy and the molecular weight distribution is relatively narrow, solution polymerization is preferable. In order to remove impurities contained in the homopolymer, a reprecipitation purification operation is preferably performed. Furthermore, in order to obtain samples having different mass average molecular weights, homopolymers having a certain mass average molecular weight may be subjected to molecular weight fractionation by known methods such as solvent fractionation, precipitation fractionation, and chromatographic fractionation. The polymerization initiator, depending on the case, the molecular weight modifier or chain transfer agent, and the polymerization solvent are not particularly limited.

Next, the type and composition ratio of the eluent, the analytical column, and the column temperature are determined so that the top points of the elution curves of the respective homopolymers U having different mass average molecular weights coincide. The measurement conditions (type of eluent, composition ratio, analytical column, column temperature) at this time are defined as critical adsorption conditions for the homopolymer U (hereinafter referred to as CA conditions). Similarly, although the CA conditions for the homopolymer T are determined, the type of eluent and the analytical column are preferably the same as those for the homopolymer U. As the eluent, a solvent that completely dissolves the homopolymers U and T is used. The column temperature is preferably 60 ° C. or lower because the eluent does not decompose or volatilize, and preferably 0 ° C. or higher because the viscosity of the eluent is low.
And among the CA conditions of the homopolymers U and T, the CA conditions of the homopolymer with a slow time at which the top point of the elution curve appears from the CA conditions of the homopolymer with a fast time at which the top point of the elution curve appears. When liquid phase chromatography is performed using a solution of the copolymer UT as a sample under measurement conditions that are changed at a constant rate (hereinafter referred to as “composition distribution measurement conditions”), the copolymer composition ratio of the copolymer UT is obtained. A corresponding elution curve can be obtained.

However, depending on the combination of structural units, it may not be possible to find CA conditions in which both the type of eluent and the analytical column are common. In such a case, it is possible to obtain an elution curve by fixing the measurement under the CA condition of one of the structural units.
The elution curve of the copolymer UT thus obtained can correspond to the elution time and the copolymer composition by any one of the following three methods. The elution curve can be read as a copolymer composition distribution curve.
Method 1: Method using NMR as a detector In this method, a sample of copolymer UT separated by an analytical column is directly introduced into an NMR apparatus, and an NMR spectrum obtained by performing NMR measurement at regular intervals, By obtaining the copolymer composition ratio, the elution time is replaced with the copolymer composition ratio. The interval for NMR measurement is preferably within 30 seconds from the point that the copolymer composition distribution curve becomes smooth.
Method 2: Method for Measuring Copolymerization Composition Ratio of Fractionated Sample by NMR In the above Method 1, a sample of copolymer UT separated by an analytical column was directly introduced into an NMR apparatus. In this method, the sample of the separated copolymer UT is once fractionated into several types, and then the fractionated sample is subjected to NMR measurement to obtain a copolymer composition ratio for each fraction. The elution time is replaced with the copolymer composition ratio. The interval for fraction collection is preferably within 30 seconds from the point that the copolymer composition distribution curve becomes smooth.
Method 3: Using a Sample with a Known Copolymerization Composition Ratio as a Standard Several types of samples with different copolymerization composition ratios (hereinafter referred to as “standard samples”) are measured under the above-described composition distribution measurement conditions and obtained with each standard sample. The time at the top of the elution curve is replaced with the copolymer composition ratio. The standard sample is preferably one having as little copolymer composition distribution as possible.
Of the above three methods, Method 1 or Method 2 is preferable from the viewpoint of more accurate copolymer composition distribution curve, and Method 3 is preferable because no special apparatus is required.
When the elution curve thus obtained is wide, it indicates that the copolymer composition distribution is wide, and conversely, when the elution curve is sharp, it indicates that the copolymer composition distribution is narrow.
The reliability of the measurement is judged by measuring the composition of the eluent sampled at a specific elution time around the apex point three times by NMR, and the error of each component is within ± 0.2%. be able to.
The structural unit of the resist polymer used in the method for analyzing the copolymer composition distribution of the present invention is arbitrary, but it preferably contains a structural unit having a lactone skeleton and a structural unit having an acid-eliminable group. Here, the “acid leaving group” means a group that decomposes or leaves by the action of an acid.

The structural unit having a lactone skeleton will be described.
When the structural unit having a lactone skeleton has a protecting group that is eliminated by an acid, it has better sensitivity. In addition, when the structural unit having a lactone skeleton has a high carbon density, that is, when the ratio of the number of carbon atoms to the total number of atoms in the structural unit is high, it has better dry etching resistance.
As the structural unit having a lactone skeleton, the structural unit represented by the formula (1-1) and the structural unit represented by the formula (1-2) are preferable from the viewpoint of dry etching resistance.
As A ¹ and A ² in the formula (1-1), from the viewpoint of high dry etching resistance, —CH ₂ — and —CH ₂ —CH ₂ — are preferable, and from the viewpoint of high solubility in an organic solvent, -O- is preferred.
R ¹ and R ^{2 in} formula (1-1) are preferably a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group from the viewpoint of high solubility in an organic solvent.
N1 in Formula (1-1) is preferably 0 from the viewpoint of high dry etching resistance.
As A ³ and A ^{4 in} formula (1-2), —CH ₂ — and —CH ₂ —CH ₂ — are preferable from the viewpoint of high dry etching resistance, and from the point of high solubility in organic solvents, -O- is preferred.
R ³ and R ^{4 in} formula (1-2) are preferably a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group from the viewpoint of high solubility in an organic solvent.
N2 in Formula (1-2) is preferably 0 from the viewpoint of high dry etching resistance.
X ² in formula (1-2) is preferably a methoxy group, an ethoxy group, or an isopropoxy group, and n2 is preferably 1 from the viewpoint of high solubility in an organic solvent.
In order to introduce a structural unit having a lactone skeleton into a polymer, a monomer having a lactone skeleton may be copolymerized. Monomers having a lactone skeleton can be used alone or in combination of two or more as required.
Examples of the monomer having a lactone skeleton include (meth) acrylic acid derivatives having a δ-valerolactone ring, (meth) acrylic acid derivatives having a γ-butyrolactone ring, and (meth) acrylic acid having a polycyclic lactone. Derivatives, 2-methylene-4-butanolide, and derivatives having a substituent on the lactone ring of these compounds.
Specific examples of the monomer having a lactone skeleton include monomers represented by the following formulas (10-1) to (10-24). In formulas (10-1) to (10-24), R represents a hydrogen atom or a methyl group.

ラクトン骨格を有する単量体としては、中でも、感度の点から、上記式（１０−３）で表される単量体、上記式（１０−５）で表される単量体、および、その光学異性体がより好ましく、ドライエッチング耐性の点から、上記式（１０−７）で表される単量体、上記式（１０−９）で表される単量体、上記式（１０−１０）で表される単量体、上記式（１０−１２）で表される単量体、上記式（１０−１４）で表される単量体、上記式（１０−２５）で表される単量体、および、これらの幾何異性体、光学異性体がより好ましく、レジスト溶媒への溶解性の点から、上記式（１０−８）で表される単量体、上記式（１０−８）で表される単量体、上記式（１０−１３）で表される単量体、上記式（１０−１９）で表される単量体、上記式（１０−１６）〜（１０−２４）で表される単量体、および、これらの幾何異性体、光学異性体がより好ましい。

Among the monomers having a lactone skeleton, in particular, from the viewpoint of sensitivity, the monomer represented by the above formula (10-3), the monomer represented by the above formula (10-5), and its An optical isomer is more preferable, and from the viewpoint of dry etching resistance, a monomer represented by the above formula (10-7), a monomer represented by the above formula (10-9), and the above formula (10-10) ), A monomer represented by the formula (10-12), a monomer represented by the formula (10-14), and a formula (10-25). Monomers, and geometric isomers and optical isomers thereof are more preferable. From the viewpoint of solubility in a resist solvent, the monomer represented by the above formula (10-8), the above formula (10-8) ), A monomer represented by the above formula (10-13), a monomer represented by the above formula (10-19), the above formula (1) Monomer represented by -16) - (10-24), and, these geometric isomers, optical isomers are more preferred.

Next, the structural unit having an acid leaving group will be described.
The acid leaving group is a group that decomposes under the action of an acid, and the structural unit is represented by the following formulas (2-1), (2-2), (2-3), and (3-5). And the like.

（式（２−１）中、Ｒ³¹は水素原子またはメチル基を表し、Ｒ¹は炭素数１〜３のアルキル基を表し、Ｘ¹は、置換基としてヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基およびアミノ基からなる群より選ばれる少なくとも一つの基を有していてもよい炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基またはアミノ基を表し、ｎ１は０〜４の整数を表す。なお、ｎ１が２以上の場合にはＸ¹として複数の異なる基を有することも含む。
式（２−２）中、Ｒ³²は水素原子またはメチル基を表し、Ｒ²、Ｒ³はそれぞれ独立に炭素数１〜３のアルキル基を表し、Ｘ²は、置換基としてヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基およびアミノ基からなる群より選ばれる少なくとも一つの基を有していてもよい炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基またはアミノ基を表し、ｎ２は０〜４の整数を表す。なお、ｎ２が２以上の場合にはＸ²として複数の異なる基を有することも含む。
式（２−３）中、Ｒ³³は水素原子またはメチル基を表し、Ｒ⁴は炭素数１〜３のアルキル基を表し、Ｘ³は、置換基としてヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基およびアミノ基からなる群より選ばれる少なくとも一つの基を有していてもよい炭素数１〜６の直鎖または分岐アルキル基、ヒドロキシ基、カルボキシ基、炭素数１〜６のアシル基、炭素数１〜６のアルコキシ基、炭素数１〜６のアルコールでエステル化されたカルボキシ基またはアミノ基を表し、ｎ３は０〜４の整数を表し、ｑは０または１を表す。なお、ｎ３が２以上の場合にはＸ³として複数の異なる基を有することも含む。）

(In formula (2-1), R ³¹ represents a hydrogen atom or a methyl group, R ¹ represents an alkyl group having 1 to 3 carbon atoms, and X ¹ represents a hydroxy group, a carboxy group, or a carbon number 1 as a substituent. Carbon which may have at least one group selected from the group consisting of an acyl group having 6 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group A linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms. or an amino group, n1 also includes having a representative. Incidentally, n1 is 2 or more different groups as X ¹ in the case an integer of 0 to 4.
In the formula (2-2), R ³² represents a hydrogen atom or a methyl group, R ² and R ³ each independently represents an alkyl group having 1 to 3 carbon atoms, and X ² represents a hydroxy group, carboxy as a substituent. At least one group selected from the group consisting of a group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group C1-6 linear or branched alkyl group, hydroxy group, carboxy group, C1-6 acyl group, C1-6 alkoxy group, C1-6 alcohol ester Represents a converted carboxy group or amino group, and n2 represents an integer of 0 to 4. Incidentally, also includes having a plurality of different groups as X ² in the case of n2 is 2 or more.
In Formula (2-3), R ³³ represents a hydrogen atom or a methyl group, R ⁴ represents an alkyl group having 1 to 3 carbon atoms, and X ³ represents a hydroxy group, a carboxy group, or 1 to 3 carbon atoms as a substituent. 6 carbon atoms which may have at least one group selected from the group consisting of an acyl group having 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and an amino group A linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or Represents an amino group, n3 represents an integer of 0 to 4, and q represents 0 or 1; In addition, when n3 is 2 or more, it includes having a plurality of different groups as X ³ . )

（式（３−５）中、Ｒ³⁵は水素原子またはメチル基を表す。）
具体的には、以下で示される化合物が挙げられる。

(In the formula (3-5), R ³⁵ represents a hydrogen atom or a methyl group.)
Specifically, the compound shown below is mentioned.

本発明のレジスト用重合体は、さらに、上記以外の構成単位を含有していてもよい。すなわち、本発明のレジスト用重合体は、酸脱離性基を有する単量体およびラクトン骨格を有する単量体以外の共重合可能な他の単量体を共重合したものであってもよい。

The resist polymer of the present invention may further contain structural units other than those described above. That is, the resist polymer of the present invention may be obtained by copolymerizing a monomer having an acid leaving group and another copolymerizable monomer other than a monomer having a lactone skeleton. .

The resist polymer of the present invention can contain, for example, a structural unit having an alicyclic skeleton that does not have an acid leaving group. The structural unit having an alicyclic skeleton is a structural unit having a structure having one or more cyclic hydrocarbon groups. The structural unit having an alicyclic skeleton may be one type or two or more types.
A resist polymer containing a structural unit having an alicyclic skeleton is excellent in dry etching resistance. Furthermore, when these structural units have a hydroxyl group and a cyano group, they have better resist pattern shape stability.
The structural unit having an alicyclic skeleton is represented by the structural unit represented by the following formula (11-1) and the following formula (11-2) from the viewpoint of high dry etching resistance required for the resist. A structural unit, a structural unit represented by the following formula (11-3) is preferred.

（式（１１−１）中、Ｒ^３１、Ｘ^１、ｎ１は、式（２−１）と同義である。
式（１１−２）中、Ｒ^３２、Ｘ^２、ｎ２は、式（２−２）と同義である。
式（１１−３）中、Ｒ^３３、Ｘ^３、ｎ３は、式（２−３）と同義である。）
なお、式（１１−１）、式（１１−２）および式（１１−３）において、Ｘ^１〜Ｘ^３で置換される位置は、環状構造のどの位置であってもよい。
脂環式骨格を有する構成単位を重合体に導入するためには、脂環式骨格を有する単量体を共重合すればよい。脂環式骨格を有する単量体は、１種、あるいは、必要に応じて２種以上を組み合わせて使用することができる。
脂環式骨格を有する単量体としては、例えば、（メタ）アクリル酸シクロヘキシル、（メタ）アクリル酸イソボルニル、（メタ）アクリル酸ノルボルニル、（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タジエニル、および、これらの化合物の環式炭化水素基上に置換基を有する誘導体が好ましい。
脂環式骨格を有する単量体として、具体的には、下記式（１４−１）〜（１４−１４）で表される単量体が挙げられる。式（１４−１）〜（１４−１４）中、Ｒは水素原子またはメチル基を表す。

(In formula (11-1), R ³¹ , X ¹ and n1 have the same meanings as in formula (2-1).
In formula (11-2), R ³² , X ² and n2 have the same meaning as in formula (2-2).
In formula (11-3), R ³³ , X ³ and n3 have the same meaning as in formula (2-3). )
In the formula (11-1), the formula (11-2), and the formula (11-3), the position substituted with X ^{1 to} X ³ may be any position in the cyclic structure.
In order to introduce a structural unit having an alicyclic skeleton into a polymer, a monomer having an alicyclic skeleton may be copolymerized. Monomers having an alicyclic skeleton can be used alone or in combination of two or more as required.
Examples of the monomer having an alicyclic skeleton include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, and tricyclodeca (meth) acrylate. Nyl, dicyclopentadienyl (meth) acrylate, and derivatives having a substituent on the cyclic hydrocarbon group of these compounds are preferred.
Specific examples of the monomer having an alicyclic skeleton include monomers represented by the following formulas (14-1) to (14-14). In formulas (14-1) to (14-14), R represents a hydrogen atom or a methyl group.

また、それ以外の共重合可能な他の単量体としては、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸２−エチルヘキシル、（メタ）アクリル酸ｎ−プロピル、（メタ）アクリル酸イソプロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸イソブチル、（メタ）アクリル酸ｔｅｒｔ−ブチル、（メタ）アクリル酸メトキシメチル、（メタ）アクリル酸ｎ−プロポキシエチル、（メタ）アクリル酸ｉｓｏ−プロポキシエチル、（メタ）アクリル酸ｎ−ブトキシエチル、（メタ）アクリル酸ｉｓｏ−ブトキシエチル、（メタ）アクリル酸ｔｅｒｔ−ブトキシエチル、（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−ｎ−ブチル、（メタ）アクリル酸２−エトキシエチル、（メタ）アクリル酸１−エトキシエチル、（メタ）アクリル酸２,２,２−トリフルオロエチル、（メタ）アクリル酸２,２,３,３−テトラフルオロ−ｎ−プロピル、（メタ）アクリル酸２,２,３,３,３−ペンタフルオロ−ｎ−プロピル、α−（トリ）フルオロメチルアクリル酸メチル、α−（トリ）フルオロメチルアクリル酸エチル、α−（トリ）フルオロメチルアクリル酸２−エチルヘキシル、α−（トリ）フルオロメチルアクリル酸ｎ−プロピル、α−（トリ）フルオロメチルアクリル酸ｉｓｏ−プロピル、α−（トリ）フルオロメチルアクリル酸ｎ−ブチル、α−（トリ）フルオロメチルアクリル酸ｉｓｏ−ブチル、α−（トリ）フルオロメチルアクリル酸ｔｅｒｔ−ブチル、α−（トリ）フルオロメチルアクリル酸メトキシメチル、α−（トリ）フルオロメチルアクリル酸エトキシエチル、α−（トリ）フルオロメチルアクリル酸ｎ−プロポキシエチル、α−（トリ）フルオロメチルアクリル酸ｉｓｏ−プロポキシエチル、α−（トリ）フルオロメチルアクリル酸ｎ−ブトキシエチル、α−（トリ）フルオロメチルアクリル酸ｉｓｏ−ブトキシエチル、α−（トリ）フルオロメチルアクリル酸ｔｅｒｔ−ブトキシエチル等の直鎖または分岐構造を持つ（メタ）アクリル酸エステル；
スチレン、α−メチルスチレン、ビニルトルエン、ｐ−ヒドロキシスチレン、ｐ−ｔｅｒｔ−ブトキシカルボニルヒドロキシスチレン、３,５−ジ−ｔｅｒｔ−ブチル−４−ヒドロキシスチレン、３,５−ジメチル−４−ヒドロキシスチレン、ｐ−ｔｅｒｔ−ぺルフルオロブチルスチレン、ｐ−（２−ヒドロキシ−ｉｓｏ−プロピル）スチレン等の芳香族アルケニル化合物；
アクリル酸、メタクリル酸、マレイン酸、無水マレイン酸、イタコン酸、無水イタコン酸等の不飽和カルボン酸およびカルボン酸無水物；
エチレン、プロピレン、ノルボルネン、テトラフルオロエチレン、アクリルアミド、Ｎ−メチルアクリルアミド、Ｎ,Ｎ−ジメチルアクリルアミド、塩化ビニル、エチレン、フッ化ビニル、フッ化ビニリデン、テトラフルオロエチレン、ビニルピロリドン等が挙げられる。これらの単量体は、必要に応じて１種または２種以上を組み合わせて使用することができる。
他の単量体は、本発明の効果を大きく損なわない範囲内で用いることができる。

Other copolymerizable monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and n-propyl (meth) acrylate. , Isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, methoxymethyl (meth) acrylate, n-propoxyethyl (meth) acrylate, ( Iso-propoxyethyl (meth) acrylate, n-butoxyethyl (meth) acrylate, iso-butoxyethyl (meth) acrylate, tert-butoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, ( (Meth) acrylic acid 3-hydroxypropyl, (meth) acrylic acid 2-hydroxy-n-propyl Pill, 4-hydroxy-n-butyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 1-ethoxyethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, (Meth) acrylic acid 2,2,3,3-tetrafluoro-n-propyl, (meth) acrylic acid 2,2,3,3,3-pentafluoro-n-propyl, α- (tri) fluoromethylacrylic Acid methyl, α- (tri) fluoromethyl acrylate ethyl, α- (tri) fluoromethyl acrylate 2-ethylhexyl, α- (tri) fluoromethyl acrylate n-propyl, α- (tri) fluoromethyl acrylate iso -Propyl, α- (tri) fluoromethyl acrylate n-butyl, α- (tri) fluoromethyl acrylate iso-butyl, α- (tri) fluoromethyl Tert-butyl acrylate, methoxymethyl α- (tri) fluoromethyl acrylate, ethoxyethyl α- (tri) fluoromethyl acrylate, n-propoxyethyl α- (tri) fluoromethyl acrylate, α- (tri) fluoro Iso-propoxyethyl methyl acrylate, n-butoxyethyl α- (tri) fluoromethyl acrylate, iso-butoxyethyl α- (tri) fluoromethyl acrylate, tert-butoxyethyl α- (tri) fluoromethyl acrylate, etc. (Meth) acrylic acid ester having a linear or branched structure of
Styrene, α-methylstyrene, vinyltoluene, p-hydroxystyrene, p-tert-butoxycarbonylhydroxystyrene, 3,5-di-tert-butyl-4-hydroxystyrene, 3,5-dimethyl-4-hydroxystyrene, aromatic alkenyl compounds such as p-tert-perfluorobutylstyrene and p- (2-hydroxy-iso-propyl) styrene;
Unsaturated carboxylic acids and carboxylic anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride;
Examples include ethylene, propylene, norbornene, tetrafluoroethylene, acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, vinyl chloride, ethylene, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, and vinylpyrrolidone. These monomers can be used alone or in combination of two or more as required.
Other monomers can be used as long as the effects of the present invention are not significantly impaired.

There is no restriction | limiting in particular about the manufacturing method of the polymer for resists used for the analysis method of the copolymer composition distribution of this invention.
As the polymerization initiator used in the production of the resist polymer used in the method for analyzing the copolymer composition distribution of the present invention, those that generate radicals efficiently by heat are preferred. Examples of such a polymerization initiator include azo compounds such as 2,2′-azobisisobutyronitrile and dimethyl-2,2′-azobisisobutyrate; 2,5-dimethyl-2,5- And organic peroxides such as bis (tert-butylperoxy) hexane. In addition, when producing a resist polymer used in ArF excimer laser (wavelength: 193 nm) lithography, the light transmittance of the resulting resist polymer (transmittance for light with a wavelength of 193 nm) is not reduced as much as possible. As the polymerization initiator to be used, those having no aromatic ring in the molecular structure are preferable. Furthermore, in consideration of safety during polymerization, the polymerization initiator used preferably has a 10-hour half-life temperature of 60 ° C. or higher.

A chain transfer agent may be used when producing a resist polymer used in the copolymer composition distribution analysis method of the present invention. By using a chain transfer agent, when a low molecular weight polymer is produced, the amount of polymerization initiator used can be reduced, and the molecular weight distribution of the resulting polymer can be reduced.
Suitable chain transfer agents include, for example, 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-decanethiol, 1-tetradecanethiol, cyclohexanethiol, 2-methyl-1-propanethiol, 2-mercapto Examples include ethanol and α-thioglycerol.
In the polymerization reaction, a polymer having a radical at the growth end is generated. However, when a chain transfer agent is used, the radical at the growth end pulls out hydrogen of the chain transfer agent, and the growth end becomes a deactivated polymer. On the other hand, the chain transfer agent from which hydrogen has been extracted becomes a structure having a radical, that is, a radical body, and the monomer is chain-polymerized again starting from this radical body. Therefore, a chain transfer residue exists at the terminal of the obtained polymer. When producing a resist polymer used in ArF excimer laser (wavelength: 193 nm) lithography, the chain used is that the light transmittance (transmittance with respect to light having a wavelength of 193 nm) of the resulting resist polymer is not lowered as much as possible. As the transfer agent, those having no aromatic ring are preferable.

The amount of the polymerization initiator used is not particularly limited, but is preferably 0.3 mol% or more based on the total amount of monomers used for the copolymerization from the viewpoint of increasing the yield of the copolymer. From the viewpoint of narrowing the molecular weight distribution, it is preferably 30 mol% or less based on the total amount of monomers used for copolymerization.
The amount of chain transfer agent used is not particularly limited, but it is preferably 0 mol% or more based on the total amount of monomers used for copolymerization from the viewpoint of narrowing the molecular weight distribution of the copolymer. From the viewpoint of not deteriorating resist performance such as sensitivity and resolution when used as a product, adhesion to a metal surface, etc., 30 mol% or less is preferable.
The method for producing the polymer of the present invention is not particularly limited, but solution polymerization is generally preferred.
Although the polymerization temperature in the solution polymerization method is not particularly limited, it is usually preferably in the range of 50 to 150 ° C.

The organic solvent used in the solution polymerization method is preferably a solvent that can dissolve all of the monomer used, the polymerization initiator and the resulting polymer, and, when a chain transfer agent is used, the chain transfer agent. Examples of such an organic solvent include 1,4-dioxane, isopropyl alcohol, acetone, tetrahydrofuran (hereinafter also referred to as “THF”), methyl ethyl ketone (hereinafter also referred to as “MEK”), methyl isobutyl ketone (hereinafter referred to as “MIBK”). And γ-butyrolactone, propylene glycol monomethyl ether acetate (hereinafter also referred to as “PGMEA”), ethyl lactate, and the like.
The amount of the organic solvent charged into the polymerization vessel is not particularly limited and may be determined as appropriate. Usually, it uses within the range of 30-700 mass% with respect to the monomer whole quantity used for copolymerization.

The polymer solution produced by a method such as solution polymerization can be prepared with a good solvent viscosity such as 1,4-dioxane, acetone, THF, MEK, MIBK, γ-butyrolactone, PGMEA, and ethyl lactate as necessary. Then, it is dropped into a large amount of poor solvent such as methanol or water to precipitate the polymer. This process is generally called reprecipitation and is very effective for removing unreacted monomers, polymerization initiators, and the like remaining in the polymerization solution. If these unreacted substances remain as they are, there is a possibility of adversely affecting the resist performance. Therefore, it is preferable to remove them as much as possible. The reprecipitation process may be unnecessary depending on circumstances. Thereafter, the precipitate is filtered off and sufficiently dried to obtain a polymer used in the method for analyzing a copolymer composition distribution of the present invention.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. In addition, “part” in each example and comparative example means “part by mass” unless otherwise specified.
Moreover, the physical property etc. of the polymer manufactured as follows were measured.
<Mass-Mass Average Molecular Weight of Resist Polymer>
About 20 mg of the resist polymer is dissolved in 5 mL of tetrahydrofuran, and filtered through a 0.5 μm membrane filter to prepare a sample solution. This sample solution is measured using gel permeation chromatography (GPC) manufactured by Tosoh. did. In this measurement, a separation column made of Showa Denko Co., Ltd., Shodex GPC K-805L (trade name) in series was used, the solvent was tetrahydrofuran or chloroform, the flow rate was 1.0 mL / min, and the detector was a differential refractometer. The measurement was performed using polystyrene as a standard polymer at a measurement temperature of 40 ° C. and an injection amount of 0.1 mL.
<Average copolymer composition ratio of resist polymer (mol%)>
^It calculated | required by the measurement of < ¹ > H-NMR. This measurement is performed using JSX Corporation GSX-400 type FT-NMR (trade name), deuterated chloroform, deuterated acetone or deuterated about 5 mass% resist polymer sample. The dimethyl sulfoxide solution was put in a test tube having a diameter of 5 mmφ, and the measurement was carried out 64 times in a single pulse mode at a measurement temperature of 40 ° C., an observation frequency of 400 MHz.
Moreover, using the produced polymer, a resist composition was prepared as follows, and its physical properties and the like were measured.

<Synthesis Example 1>
A resist copolymer comprising a structural unit (A) having a lactone skeleton and a structural unit (B) having an acid-eliminable group was synthesized by the following method.
In a flask equipped with a nitrogen inlet, a stirrer, a condenser, and a thermometer, under a nitrogen atmosphere, 8- or 9-acryloyloxy-4-oxatricyclo [5.2.1] represented by the following formula (51): .0 ^2,6] decan-3-one (hereinafter, referred to as OTDA.) 26.6 parts,

下記式（５２）で表される２−メタクリロイルオキシ−２−エチルアダマンタン（以下、ＥＡｄＭＡと言う。）１９.８部、

19.8 parts of 2-methacryloyloxy-2-ethyladamantane (hereinafter referred to as EAdMA) represented by the following formula (52);

ＰＧＭＥＡ１３９.４部、２,２'−アゾビスイソブチロニトリル（以下、ＡＩＢＮと言う。）２.６２部を全量入れ、攪拌しながら湯浴の温度を８０℃に上げ、その温度で７時間重合させた。次いで、得られた反応溶液をＰＧＭＥＡで約２倍に希釈し、約１０倍量のメタノール中に攪拌しながら滴下し、白色の析出物（共重合体Ｇ）の沈殿を得た。得られた沈殿を濾別し、減圧下６０℃で約４０時間乾燥した。得られた共重合体Ｇの各物性を測定した結果、質量質量平均分子量（Ｍｗ）１３,５００、分子量分布（Ｍｗ／Ｍｎ）２.０３、平均共重合組成比ＯＴＤＡ／ＥＡｄＭＡ＝４４モル％／５６モル％であった。

139.4 parts of PGMEA, 2.62 parts of 2,2′-azobisisobutyronitrile (hereinafter referred to as AIBN) were added in total amount, and the temperature of the hot water bath was raised to 80 ° C. with stirring, and the temperature was maintained for 7 hours. Polymerized. Next, the obtained reaction solution was diluted about 2-fold with PGMEA and dropped into about 10-fold amount of methanol with stirring to obtain a white precipitate (copolymer G). The resulting precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. As a result of measuring each physical property of the obtained copolymer G, mass mass average molecular weight (Mw) 13,500, molecular weight distribution (Mw / Mn) 2.03, average copolymer composition ratio OTDA / EAdMA = 44 mol% / It was 56 mol%.

<Synthesis Example 2>
Synthesis of EAdMA homopolymers having different mass average molecular weights (EM-1, EM-2, EM-3, and EM-4) A flask equipped with a nitrogen inlet, a stirrer, a condenser, and a thermometer under a nitrogen atmosphere Then, 12.4 parts of EAdMA, 23.0 parts of THF, and 0.66 parts of AIBN were added in total, and the temperature of the hot water bath was raised to 65 ° C. with stirring, and polymerization was performed at that temperature for 7 hours. Next, the obtained reaction solution was diluted about 2 times with THF, and dropped into about 10 times amount of methanol with stirring to obtain a precipitate of a white precipitate (homopolymer EM-1). The resulting precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained homopolymer EM-1 was Mw = 2100 and Mw / Mn = 1.46.
Next, a homopolymer EM-2 with Mw = 4700 and Mw / Mn = 1.86 was obtained except that the amount of AIBN used was changed to 0.06 part.
Further, except that the amounts of THF and AIBN used were changed to 15.2 parts and 0.04 parts, respectively, the same operation as described above was carried out to obtain a homopolymer EM-3 having Mw = 8200 and Mw / Mn = 1.96. Obtained.
Then, except that the amounts of THF and AIBN used were changed to 10.1 parts and 0.04 parts, respectively, the same operation as described above was performed, and a homopolymer EM-4 having Mw = 13500 and Mw / Mn = 2.02 was obtained. Obtained.

<Example 1>
1 mg of each of the homopolymers EM-1, EM-2, EM-3, and EM-4, and the copolymer G for resist, and 1 mL of a mixed solvent of chloroform / acetonitrile = 80% by volume / 20% by volume. The sample solution of each homopolymer was prepared by mixing.
One eluent tank filled with chloroform (CLF) / acetonitrile (ATN) = 80 vol% / 20 vol%, which was ultrasonically degassed in advance, and a metered liquid feed pump PU-980 manufactured by JASCO Corporation, GL Sciences column jacket LCD-250 equipped with 100 μL sample loop, switching valve, and column jacket temperature controller NESLAB RTE-111, and Phenomenex column KROMASIL5C4 (fixed layer: alkyl having 4 carbon atoms) It is composed of a separation column unit in which a silica gel chemically modified with a chain having a diameter of 5 μm, a column: length 250 mm × inner diameter 4.6 mm) and an evaporative light scattering detector (ELSD) PL-EMD960 manufactured by Polymer Laboratories. Liquid phase chromatography ( To C) apparatus, and introducing the sample solution 50μL of homopolymer EM-1 of EAdMA, performs LC measurement was obtained elution curve of EM-1 in 20 minutes. The eluent flow rate was 0.2 mL / min, the column oven temperature was 24 ° C., and the ELSD gas flow rate and detection temperature were 7.2 L / min and 65 ° C., respectively.
The elution curves of the homopolymers EM-2, EM-3, and EM-4 were obtained in the same manner as described above for 20 minutes.
The top points of the elution curves of EM-1 to EM-4 coincided, and the above conditions became the critical adsorption conditions (CA conditions) for the homopolymer of EAdMA.
Then, under the CA conditions of the EAdMA homopolymer, an elution curve of the resist copolymer G was obtained in 20 minutes by the same operation as described above.
In order to confirm whether the elution curve of the resist copolymer G obtained here has a distribution corresponding to the copolymer composition, the detector was a nuclear magnetic resonance spectroscopy (NMR) apparatus INOVA750 manufactured by Varian Technologies, Inc. Except that the concentration was 50 mg / mL, an elution curve of the copolymer G homopolymer and a ¹ H-NMR spectrum at each NMR measurement point were obtained in 20 minutes in the same manner as described above. The elution curve of the copolymer G homopolymer obtained by this measurement was the same as the elution curve obtained by the measurement using ELSD as a detector. The detection cell volume was 60 μL, the detection temperature was 55 ° C., the number of spectrum integrations was 8 times, and the NMR measurement interval was 18 seconds. And when the copolymer composition ratio of the copolymer G was calculated | required from the < ¹ > H-NMR spectrum in each measurement point, the relationship between elution time and copolymer composition ratio like Table 1 and FIG. 1 was obtained.

実施例１は、迅速、簡便、正確にレジスト用共重合体の共重合組成分布が測定できる方法であった。

Example 1 was a method by which the copolymer composition distribution of the resist copolymer could be measured quickly, simply and accurately.

Claims (7)

  Analysis method of copolymer composition distribution of resist copolymer by critical adsorption chromatography.   A method for analyzing a copolymer composition of a copolymer containing the structural units (A) and (B) using a liquid phase chromatography apparatus, the single weight of the structural unit (A) having different molecular weights determined in advance. Combinations of eluent composition and column temperature at which the peak points of the elution curves measured by the liquid phase chromatography method of the coalescence match with the column temperature (condition A), or homopolymer liquids having different molecular weights of the structural unit (B) Liquid phase chromatography is performed under the condition of the combination of eluent composition and column temperature (condition B) where the peak points of the elution curves measured by the phase chromatography method match, and the binary system is based on the obtained elution curves A method for analyzing a copolymer composition of a resist copolymer for analyzing the composition of the copolymer. A method for analyzing a copolymer composition of a copolymer containing the structural units (A) and (B) using a liquid phase chromatography apparatus, wherein homopolymers having different molecular weights of the structural unit (A) are previously prepared. Combinations of eluent composition and column temperature at which the top points of the elution curves measured by liquid phase chromatography coincide with each other (condition A), elution time A under the conditions, and molecular weight of the structural unit (B) are different. The combination of eluent composition and column temperature at which the top points of the elution curves measured by the liquid phase chromatography method of the homopolymer coincide with each other (condition B), and the elution time B under the conditions are obtained. And elution time B,
In the case of elution time A <elution time B, the conditions for starting liquid phase chromatography are condition A, and the eluent composition and column temperature are changed so that the condition for ending is condition B.
When elution time B <elution time A, the condition for starting liquid phase chromatography is Condition B, and the liquid phase chromatography is performed by changing the eluent composition and the column temperature so that the condition for ending is Condition A. Carried out,
A method for analyzing a copolymer composition of a resist copolymer, wherein the composition of a binary copolymer is analyzed based on the obtained elution curve.   4. The analysis method according to claim 2, wherein one of the structural units (A) and (B) is a structural unit having a lactone skeleton, and the other is a structural unit having an acid-eliminable group.   The analysis method according to claim 2, wherein the eluent used contains chloroform and tetrahydrofuran. 6. The analysis method according to claim 4, wherein the structural unit having a lactone skeleton is at least one selected from the group consisting of the following formulas (1-1) to (1-2).

(In formula (1-1), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹ and R ² are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, and a carboxy group. Or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, wherein A ¹ and A ² are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or carbon. Represents a carboxy group esterified with an alcohol having a number of 1 to 6, or A ¹ and A ² together represent —O—, —S—, —NH—, or a methylene chain having 1 to 6 carbon atoms; [— (CH ₂ ) _k — (k represents an integer of 1 to 6)] X ¹ is a hydroxy group, a carboxy group, a C 1-6 acyl group, or a C 1-6 as a substituent. Alcohol esterified with alcohol A linear or branched alkyl group having 1 to 6 carbon atoms which may have at least one group selected from the group consisting of a boxy group, a cyano group and an amino group, a hydroxy group, a carboxy group, and a 1 to 6 carbon atoms An acyl group, an alkoxy group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, a cyano group, or an amino group, and n1 represents an integer of 0 to 4. n1 is 2 In the above case, X ¹ includes a plurality of different groups.
In formula (1-2), R ¹² represents a hydrogen atom or a methyl group, and R ³ and R ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or Represents a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, and A ³ and A ⁴ each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carbon number. Represents a carboxy group esterified with an alcohol of 1 to 6, or A ³ and A ⁴ together form —O—, —S—, —NH— or a methylene chain having 1 to 6 carbon atoms [ - _(CH 2) _l - represents a (l is an integer of 1-6)]. X ² is at least one selected from the group consisting of a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, a cyano group, and an amino group as a substituent. C1-C6 linear or branched alkyl group which may have one group, a hydroxy group, a carboxy group, a C1-C6 acyl group, a C1-C6 alkoxy group, C1-C1 6 represents a carboxy group, a cyano group or an amino group esterified with an alcohol of 6, and n2 represents an integer of 0 to 4. Incidentally, also includes having a plurality of different groups as X ² in the case of n2 is 2 or more. ) The analytical method according to any one of claims 4 to 6, wherein the structural unit having an acid leaving group is represented by the following formula (2-1).

(In Formula (2-1), R ³¹ represents a hydrogen atom or a methyl group, R ¹ represents an alkyl group having 1 to 3 carbon atoms, and X ¹ represents a hydroxy group, a carboxy group, or a carbon number 1 as a substituent. A straight chain or branched chain having 1 to 6 carbon atoms, which may have at least one group selected from the group consisting of an acyl group of -6, a carboxy group esterified with an alcohol having 1 to 6 carbons, and an amino group An alkyl group, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxy group or an amino group esterified with an alcohol having 1 to 6 carbon atoms, and n1 is 0 Represents an integer of ˜4, and when n1 is 2 or more, it includes that X ¹ has a plurality of different groups.