JP2003238629A - Polymer for chemically amplified photoresist and photoresist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer for a chemically amplified photoresist suitable for an ArF excimer laser and a photoresist composition. <P>SOLUTION: The polymer for a chemically amplified photoresist is represented by general formula (I). General formula (I) shows a copolymer formed by copolymerizing two monomer components having the numbers of units of (a) and (b), respectively, or by copolymerizing three monomer components having the number of units of (a), (b), and (c), respectively, wherein the bonding state of the two or three monomer components may be either at random or in block. In general formula (I), R<SB>1</SB>, R<SB>2</SB>and R<SB>3</SB>are each a hydrogen atom or a methyl group which may be either the same as or different from each other. R<SB>4</SB>is any of a hydrogen atom, 1-12C alkyl group, cyclic alkyl group, alkoxyalkyl group, cyclic ether group and cyclic ester group and may be alone or a mixture of two or more kinds of groups. The a/(a+b+c) is 0.2-0.8, b/(a+b+c) is 0.05-0.5 and c/(a+b+c) is 0-0.5. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polymer for a chemically amplified photoresist and a photoresist composition.

[0002]

2. Description of the Related Art In general, a positive photoresist uses a sensitizer having a quinonediazide group such as a naphthoquinonediazide compound and an alkali-soluble resin (for example, a novolac phenolic resin). The positive photoresist having such a composition exhibits high resolution when developed with an alkaline solution, and is used for manufacturing semiconductors such as IC and LSI and circuit substrates such as LCD. Further, since the novolac type phenol resin has a structure having many aromatic rings, it has high dry etching resistance and heat resistance against plasma dry etching after exposure. Up to now, many positive photoresists containing a novolac phenolic resin and a naphthoquinonediazide type photosensitizer have been developed and put into practical use, and great results have been achieved in line width processing up to about 0.3 μm to 2 μm.

However, in recent years, as the demand for higher integration of semiconductors has increased year by year, it has become necessary to process finer line widths.
The use of excimer light such as KrF, ArF, and F _{2 having} shorter wavelengths as a light source is under study. These lights are lights having wavelengths of 248 nm, 193 nm, and 157 nm, respectively, and the phenol resin has poor transparency due to absorption of light by its own aromatic ring, and light does not easily reach the bottom of the resist. Therefore, the amount of exposure at the bottom of the resist is reduced, and only a defective pattern with a taper or the like can be obtained after development. Therefore, polyhydroxystyrene for KrF, acrylic resin, cycloolefin resin for ArF, and fluorine resin for F ₂ are used as the base resin, and the acid generated from the photoacid generator is used as a catalyst. Amplification systems are being considered for application.

For the KrF excimer light, application of polyhydroxystyrene has been mainly studied, and its practical application has been advanced. However, studies are underway for further integration of semiconductors, and it is necessary to apply ArF excimer light having a shorter wavelength. In that case, polyhydroxystyrene cannot be used because it has no transparency,
New applications for acrylic resins and cycloolefin resins are being studied. Acrylic resins as photoresist resins are excellent in terms of transparency and sensitivity, but have the drawback of being inferior in dry etching resistance.
When a norbornene / maleic anhydride resin, which is a cycloolefin resin, is used, it is excellent in dry etching resistance, heat resistance, etc., but the ArF wavelength (193
(nm) region, and the difference in dissolution rate (dissolution contrast / resolution) between the exposed portion and the unexposed portion in the alkaline developer is insufficient. Further, a hybrid type polymer in which an acrylic monomer is copolymerized with a cycloolefin polymer has been studied, but a polymer satisfying all the required properties of the photoresist for ArF excimer light has not been found yet. Is the actual situation.

[0005]

The present invention provides a polymer for a chemically amplified photoresist and a photoresist composition which are suitable for ArF excimer light and have excellent resolution, heat resistance, dry etching resistance, sensitivity and transparency. It is a thing.

[0006]

The above objects are achieved by the present invention described in (1) to (6) below. (1) A polymer for a chemically amplified photoresist represented by the general formula (I).

[Chemical 2] The general formula (I) represents a polymer obtained by copolymerizing two kinds of monomer components represented by the number of units a and b, or three kinds of monomer components represented by the number of units a, b, and c. The bonding state of the three kinds or three kinds of monomer components may be random or block. In the general formula (I), R ₁ , R ₂ , and R ₃ represent either a hydrogen atom or a methyl group, and may be the same or different. R ₄ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an alkoxyalkyl group,
Represents one of a cyclic ether group and a cyclic ester group,
You may use individually or in mixture of 2 or more types. a / (a + b + c) is 0.2 to 0.8, b / (a + b +)
c) is 0.05 to 0.5, and c / (a + b + c) is 0 to
It is 0.5. (2) The chemically amplified photoresist polymer is G
Number average molecular weight (Mn) measured by PC is 1000 to 10
And the degree of dispersion (Mw / Mn) is 1.0
The polymer for a chemically amplified photoresist according to (1) above, which is greater than or equal to 2.0. (3) The chemically amplified photoresist polymer is A
The polymer for chemically amplified photoresist according to the above (1) or (2), which is obtained by the TRP method (living radical polymerization method). (4) The polymer for chemically amplified photoresist is a block polymer. The polymer for chemically amplified photoresist according to any one of (1) to (3) above. (5) A chemically amplified photoresist composition containing the following (X) to (Z) as essential components. (X) The polymer for chemically amplified photoresist according to any one of (1) to (4) above, (Y) a compound that generates an acid by the action of light, and (Z) (X), (Y) and A solvent that dissolves (Z). (6) The compound (Y) that generates an acid by the action of light is the (X) polymer 1 for chemically amplified photoresist.
The chemically amplified photoresist composition according to (5) above, which is 1 to 20 parts by weight with respect to 00 parts by weight.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a polymer for a chemically amplified photoresist and a photoresist composition. First, the polymer for chemically amplified photoresist of the present invention will be described.

(X) Polymer for Chemically Amplified Photoresist Polymer for chemically amplified photoresist of the present invention (hereinafter, referred to as
“Polymer” means, as represented by the general formula (I), cyclohexyl (meth) acrylate (hereinafter referred to as “A”).
Unit)) 2-Methyladamantyl (meta)
Of the three types of monomer components of acrylate (hereinafter referred to as "B unit"), (meth) acrylate compound and / or (meth) acrylic acid compound (hereinafter referred to as "C unit"), two types of units, A unit and B unit Alternatively, it has a structure in which all three types of units are copolymerized.

The A unit in the polymer of the present invention is cyclohexyl acrylate or cyclohexyl methacrylate represented by the number of units "a" in the general formula (I), and these can be used alone or in combination. A unit content rate (a / (a + b + c))
Is 0.2 to 0.8, and more preferably 0.3 to
It is 0.7. This can improve the solubility in the photoresist solvent, the dry etching resistance, and the like.

The B unit in the polymer of the present invention is 2-methyladamantyl acrylate or 2-methyladamantyl methacrylate represented by the number of units "b" in the general formula (I), which may be used alone or in a mixture. be able to. B unit content rate (
b / (a + b + c)) is 0.05 to 0.5, and more preferably 0.1 to 0.5. As a result, heat resistance and dry etching resistance can be improved, and resolution and sensitivity can be improved.

The C units in the polymer of the present invention are acrylic acid ester, methacrylic acid ester, acrylic acid and methacrylic acid represented by the number of units "c" in the general formula (I), and these are used alone. Alternatively, they can be mixed and used. As an example of the C unit, R ₄ in the general formula (I) is a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, an alkoxy such as a methoxyethyl group, an ethoxyethyl group or a butoxyethyl group. Cycloalkyl groups such as alkyl groups, cyclopentyl groups, methylcyclopentyl groups, norbornyl groups, and cyclic ether groups such as tetrahydropyranyl groups.
Examples thereof include cyclic ester groups such as a ter group, a γ-butyrolactonyl group, and a mevalonic lactonyl group. They are,
One type or two or more types can be mixed and used in an appropriate ratio depending on the required characteristics of the photoresist. Among these,
R ₄ is a hydrogen atom, a tert-butyl group, a norbornyl group,
It is particularly preferably a mevalonic lactonyl group.
The C unit has a maximum content rate (c / (a + b + c)), if necessary, depending on the types of monomer components used as the A unit and the B unit, the composition of the photoresist composition described below, or the processing conditions such as exposure and development. It can be used up to 0.5. This makes it possible to adjust characteristics such as sensitivity and adhesion of the photoresist. In the polymer represented by the general formula (I), the C unit is not an essential component and may be a polymer consisting of only the A unit and the B unit. However, when the C unit is introduced to adjust the characteristics, the above content is included. 0.01-
It is preferably 0.5, and more preferably 0.0.
It is 3 to 0.45. The ratio of each unit in the polymer of the present invention is the amount of each unit monomer charged at the start of the polymerization reaction, and the concentration of each unit monomer remaining in the reaction solution after the completion of the polymerization reaction is measured by gas chromatography. And the calculated value.

The bonding state of each unit in the polymer of the present invention is not particularly limited. That is,
It may be a random polymer in which the two or three types of units are bonded without having regularity, or a unit may have a portion where the units are continuously bonded in the form of a block polymer. . When synthesizing a polymer,
It is common to charge monomers as raw materials all at once and react them, but by sequentially adding each monomer, it is possible to obtain a block polymer in which each unit component is bonded in a block form. Thereby, the sensitivity and resolution of the photoresist can be further improved. In any of the above cases, it suffices that two or three types of units have the structure and the protecting group and are bonded at a predetermined ratio to form a polymer.

The molecular weight of the polymer of the present invention is not particularly limited, but the number average molecular weight (Mn) is 1,000 to 10,000.
It is preferably 0, more preferably 1500 to
80,000. If the number average molecular weight of the polymer is less than the lower limit, the heat resistance may decrease, and if it exceeds the upper limit, the sensitivity of the polymer may decrease. The number average molecular weight can be controlled by adjusting the amount of monomer added during the synthesis of the polymer, the amount of polymerization initiator, the reaction temperature, and the like. Further, the dispersity (Mw / Mn) is not particularly limited, but is preferably more than 1.0 and 2.0 or less, particularly preferably 1.1 to 1.
8 If the molecular weight distribution exceeds the above upper limit, the dissolution contrast may be affected and the resolution may be reduced. Polymers below the lower limit are theoretically unsynthesizable regions. The number average molecular weight and the molecular weight distribution are GP
It is calculated based on a calibration curve prepared by using a polystyrene standard substance by C (gel permeation chromatography) measurement. For GPC measurement, tetrahydrofuran was used as an elution solvent, and the flow rate was 1.0 ml / min.
The column temperature was 40 ° C. Body: TOSOH
HLC-8020, detector: TOSOH HLC-8
RI detector built in 020, analytical column: SHOWDEX KOD-802 / 1, KF-803 / 1
Book, KF-805 / 1 book, respectively.

Next, the method for polymerizing the polymer of the present invention will be described. The polymer of the composition of the present invention can be synthesized by radical polymerization or ionic polymerization, but in order to further improve the characteristics of the photoresist, the ATR
It is preferable to synthesize by the P method (living radical polymerization method). The ATRP method is capable of producing a polymer having a narrow molecular weight distribution similarly to living anionic polymerization. In living anionic polymerization, it is important and complicated to control the mixing of impurities such as trace amounts of water, whereas the ATRP method
It is very advantageous in scale-up such as industrialization because it is easy to carry out a good reaction with a normal deoxidizing operation. ATRP as a method for polymerizing the polymer of the present invention
When the method is used, a general ATRP method initiator or catalyst can be used. Examples of the initiator include bromides such as ethyl 2-bromo-isobutenoate and 2-bromoethylbenzene, and chlorides such as benzyl chloride and dichloroacetophenone. As the catalyst, cuprous chloride, cuprous bromide, ruthenium 2+, nickel 2+ and iron 2+ complexes can be used. When the solubility of the catalyst in the solvent is a problem, good solubility can be obtained by combining an appropriate ligand. Typical ligands are 2,2'-
Bipyridyl, 4,4'-dihexyl-2,2'-bipyridyl, 4,4'-ditert-butyl-2,2'-bipyridyl, 1,1,4,7,7-pentamethyldiethylenetriamine and the like can be mentioned. . When a ruthenium 2+ complex is used, it is preferable to use a Lewis acid such as triisopropoxyaluminum in combination.

In the synthetic reaction of the polymer of the present invention,
A solvent can be used if necessary. The type of solvent is not particularly limited, but any solvent can be used as long as it dissolves the raw material monomers and polymers and does not promote the termination reaction such as chain transfer and disproportionation. For example, tetrahydrofuran (THF), dimethylformamide (DMF), dimethylacetamide, dimethylsulfoxide (DMSO),
Toluene, PGMEA, ethyl lactate, cyclohexanone and the like can be used. It is difficult to react 100% of the monomers charged during the reaction, but the residual monomer can be removed by a purification operation such as reprecipitation or dialysis.
Further, it is more preferable as a polymer for a chemically amplified photoresist to remove metal impurities through a column such as an adsorbent or an ion exchange resin (if necessary).

Next, the chemically amplified photoresist composition of the present invention (hereinafter referred to as "composition") will be described.
The composition of the present invention, the polymer, a compound that generates an acid by the action of light (hereinafter, referred to as "photoacid generator"), and a solvent that dissolves the polymer and the photoacid generator (hereinafter,
"Solvent") is added as an essential component. When the composition of the present invention is used as a photoresist, the photoacid generator generates an acid upon irradiation with light, and the action of this acid causes a deprotection reaction in the polymer. Specifically, the A unit is a cyclohexyl group and the B unit is 2
When a methyl adamantyl group and a C unit component are copolymerized, R ₄ of the C unit (excluding when R ₄ is a hydrogen atom) is eliminated by the action of an acid. The polymer of the deprotected portion is dissolved in an alkaline developing solution in the subsequent development step, and a clear difference in dissolution rate is generated between the polymer of the portion where the deprotection reaction has not occurred and the target pattern. Can be obtained by development.

(Y) Photo-acid generator The photo-acid generator used in the composition of the present invention is not particularly limited, but a sulfonium salt derivative [sulfonic acid ester (1,2,3-tri (methylsulfonyloxy) benzene] is used. Aryl alkane sulfonates such as C
_6-10 aryl C _1-2 alkane sulfonates); 2,6
Dinitrobenzyltoluene sulfonate, benzoin tosylate nadnoarylbenzene sulfonate (particularly C _6-10 aryltoluene phosphonate optionally having a benzoyl group); 2-benzoyl-2-hydroxy-2
Aralkylbenzene sulfonates such as phenylethyltoluene sulfonate (especially C _6-10 aryl-C _1-4 alkyltoluene sulfonate _optionally having a benzoyl group); disulfonic acid such as diphenyldisulfone; Lewis acid salt (triphenyl Sulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimony, triphenylsulfonium methanesulfonyl and other triarylsulfonium salts (especially triphenylsulfonium salts), etc.)], phosphonium salt derivatives, diarylhalonium salt derivatives [diaryliodonium salts ( Lewis acid salts such as diphenyliodonium hexafluorophosphate, etc.], diazonium salt derivatives (p-nitrophenyldiazonium hexafluorophosphate, etc.) Lewis, etc. salts), such as, diazomethane derivatives, triazine derivatives can be exemplified. In particular, Lewis acid salts (Lewis acid salts such as phosphonium salts) are preferable.

The amount of the photo-acid generator blended is not particularly limited, but is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymer. This improves the sensitivity and resolution of the composition. If the blending amount of the photo-acid generator is less than the lower limit value described above, the deprotection reaction of the polymer is difficult to proceed, so that an image may not be sufficiently formed. On the other hand, if the upper limit is exceeded, the deprotection reaction will proceed rapidly, and the polymer will be more likely to dissolve during development, making it difficult to form an image, and the melting point of the polymer containing the photoacid generator will be low. Therefore, the heat resistance may decrease.

(Z) Solvent The solvent to be added to the composition of the present invention is not particularly limited as long as it dissolves the polymer and the photo-acid generator, but water, alcohols, glycols, cellosolves. ,
Examples thereof include ketones, esters, ethers, amides #, and hydrocarbons. Specifically, propylene glycol monomethyl ether acetate (PGME
A), propylene glycol monoethyl ether acetate, ethyl cellosolve acetate, methyl cellosolve acetate, butyl cellosolve acetate, methoxyethyl propionate, ethoxyethyl propionate,
Examples thereof include methyl lactate, ethyl lactate, butyl lactate, ethyl acetate, butyl acetate, methyl isobutyl ketone, and methyl pentyl ketone. Among these, PGMEA, ethoxyethyl propionate, and ethyl lactate are particularly preferable from the viewpoints of solubility, coating film stability, safety, environmental impact, human impact, and economic efficiency. These are alone or 2
Used as a mixture of two or more species.

In the composition of the present invention, in addition to the components described above, if necessary, stabilizers such as antioxidants, plasticizers, surfactants, adhesion improvers, dissolution accelerators, etc. Various additives may be used.

The polymer of the present invention is synthesized as a polymer for a chemically amplified photoresist, and since 2 to 3 types of units have an appropriate constitutional ratio, it has dry etching resistance, heat resistance and dissolution contrast. (Resolution) and sensitivity could be improved. Further, by using the ATRP method as a method for synthesizing a polymer,
It was possible to further improve these characteristics.

The method for producing the composition of the present invention will be described below. First, (X) polymer and (Y) photoacid generator
(Z) Dissolves in a solvent. At that time, if necessary, a stabilizer such as an antioxidant, a plasticizer, a surfactant, an adhesion improver,
Various additives such as a dissolution accelerator may be added. The above-mentioned components may be dissolved in any order. Normal,
Under a temperature condition of about room temperature, the components are dissolved by stirring for a time sufficient to dissolve each component (for example, 6 to 12 hours). After dissolution, filter (P with a filtration accuracy of 0.1 μm or less
A TFE (polytetrafluoroethylene) filter or the like is preferably used to remove foreign matter, and the product is filled and packed in a container from which foreign matter and metal impurities have been removed in advance. When filling, it is preferable to use a machine such as an automatic filling device that does not involve humans in a clean room of class 100 or less. If necessary, the polymer or composition can be washed with an aqueous acid solution or pure water or demetallized with an ion exchange resin to remove metal impurities.

[0023]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

1. Polymer Synthesis (Example 1) Cyclohexyl Methacrylate (5 g), 2
-Methyl-2-adamantyl methacrylate (5 g), tetrahydrofuran (THF) (23.3 g), and 1-bromoethylbenzene (0.925 g) were charged into a three-necked round bottom flask equipped with a mechanical stirrer and allowed to dissolve well. Then, argon gas was blown thereinto for deoxidation. afterwards,
A nickel complex (dibromo-bis (tributylphosphine)) nickel (II), 0.312 g) was added, the temperature was raised and reflux was continued for 24 hours. The monomer reaction rate determined from the residual monomer concentration measured by gas chromatography was 95% for cyclohexyl methacrylate and 2-methyl-2-
It was 97% of adamantyl methacrylate. A crude polymer was obtained by reprecipitation from hexane. The metal catalyst remaining in the crude polymer was removed by treating the THF solution of the polymer with activated carbon. The THF solution of the polymer to which activated carbon was added was stirred for half a day and then filtered. The filtrate was poured into hexane, the polymer generated as a precipitate was taken out by filtration, and dried at 40 ° C. under reduced pressure for 1 day to obtain a target polymer. The polystyrene-equivalent number average molecular weight of this polymer measured by GPC = 7800, dispersity = 1.
It was 59. The component ratio in the polymer is a / (a + b
+ C) = 0.58 and b / (a + b + c) = 0.42.

Example 2 Cyclohexyl methacrylate (5 g), 2-methyl-2-adamantyl methacrylate (5 g), THF (39 g), and azobisisobutyronitrile (AIBN) (0.3 g) were added to a mechanical stirrer. It was charged in a three-necked round-bottomed flask equipped with-and dissolved well, and then degassed by blowing argon gas. Then, the temperature was raised and the reflux was continued for 6 hours. The monomer reaction rates determined from the residual monomer concentrations measured by gas chromatography were 95% for cyclohexyl methacrylate and 97% for 2-methyl-2-adamantyl methacrylate. Reprecipitation with hexane and drying at 40 ° C. under reduced pressure for 1 day gave the target polymer. The polystyrene-equivalent number average molecular weight of this polymer measured by GPC = 5350, and dispersity = 1.
It was 39. The component ratio in the polymer is a / (a + b
+ C) = 0.58 and b / (a + b + c) = 0.42.

(Example 3) Cyclohexyl methacrylate (5 g), 2-methyl-2-adamantyl methacrylate (5 g), butyl acrylate (2 g), tetrahydrofuran (THF) (23.3 g), and 1-bromoethylbenzene (0.925 g) Was charged into a three-necked round bottom flask equipped with a mechanical stirrer, dissolved well, and then degassed by blowing argon gas. Then, a nickel complex (dibromo-bis (tributylphosphine)) nickel (II), 0.312 g) was added, the temperature was raised and the reflux was continued for 24 hours. The monomer reaction rates determined from the residual monomer concentrations measured by gas chromatography were cyclohexyl methacrylate 95%, 2-methyl-2-adamantyl methacrylate 97%, and butyl acrylate 98%. A crude polymer was obtained by reprecipitating this with hexane. The metal catalyst remaining in the composition polymer was removed by treating the THF solution of the polymer with activated carbon. The THF solution of the polymer to which activated carbon was added was stirred for half a day,
Filtered. The filtrate was poured into hexane, the polymer generated as a precipitate was taken out by filtration, and dried at 40 ° C. under reduced pressure for 1 day to obtain a target polymer. GPC of this polymer
Polystyrene-converted number average molecular weight = 80
00 and dispersity = 1.78. The component ratio in the polymer is a / (a + b + c) = 0.44, b / (a + b +
c) = 0.32 and c / (a + b + c) = 0.24.

(Example 4) Cyclohexyl methacrylate (5 g), 2-methyl-2-adamantyl methacrylate (5 g), tetrahydrofuran (THF) (23.3 g),
Then, 1-bromoethylbenzene (0.925 g) was charged into a three-necked round bottom flask equipped with a mechanical stirrer, dissolved well, and then degassed by blowing argon gas. Then, a nickel complex (dibromo-bis (tributylphosphine)) nickel (II), 0.312 g) was added, the temperature was raised and the reflux was continued for 24 hours. The monomer reaction rate determined from the residual monomer concentration measured by gas chromatography was 95% for cyclohexyl methacrylate and 2% for cyclohexyl methacrylate.
-Methyl-2-adamantyl methacrylate was 97%. Then, butyl acrylate (2 g) was added, the temperature was further raised, and the reflux was continued for 24 hours. The reaction rate was 95% from the residual butyl acrylate concentration measured by gas chromatography. A crude polymer was obtained by reprecipitating this with hexane. The metal catalyst remaining in the composition polymer was removed by treating the polymer THF solution with activated carbon. The THF solution of the polymer to which activated carbon was added was stirred for half a day and then filtered. The filtrate was poured into hexane, the polymer generated as a precipitate was taken out by filtration,
The desired polymer was obtained by drying at 40 ° C. under reduced pressure for 1 day. The polystyrene-equivalent number average molecular weight of this polymer was 9,800 and the polydispersity was 1.85.
The component ratio in the polymer is a / (a + b + c) = 0.4
4, b / (a + b + c) = 0.32, c / (a + b +
c) = 0.24.

Comparative Example 1 2-Methyl-2-adamantyl methacrylate (5 g), butyl acrylate (5 g),
THF (39 g), and azobisisobutyronitrile (A
IBN) (0.3 g) was placed in a three-necked round bottom flask equipped with a mechanical stirrer, dissolved well, and then degassed by blowing argon gas. Then, the temperature was raised and the reflux was continued for 6 hours. The monomer reaction rates determined from the residual monomer concentrations measured by gas chromatography were 2-methyl-2-adamantyl methacrylate 97% and butyl acrylate 95%. This was reprecipitated with hexane and dried at 40 ° C. under reduced pressure for 1 day to obtain a target polymer. The polymer had a number average molecular weight in terms of polysterene measured by GPC of 9000 and a polydispersity of 2.8.
The component ratio in the polymer is b / (a + b + c) = 0.3
6, c / (a + b + c) = 0.64.

(Comparative Example 2) Cyclohexyl methacrylate (5 g), butyl acrylate (5 g), THF (39
g), and azobisisobutyronitrile (AIBN)
(0.3 g) was placed in a three-necked round bottom flask equipped with a mechanical stirrer, dissolved well, and then degassed by blowing argon gas. Then, the temperature was raised and the reflux was continued for 6 hours. The monomer reaction rates determined from the residual monomer concentrations measured by gas chromatography were 95% for cyclohexyl methacrylate and 98% for butyl acrylate. This was reprecipitated with hexane and dried at 40 ° C. under reduced pressure for 1 day to obtain the target polymer. This polymer has a number average molecular weight in terms of polysterene measured by GPC of 8500,
The dispersity was 2.52. The component ratio in the polymer is
a / (a + b + c) = 0.42, c / (a + b + c) =
It was 0.58.

For the polymers obtained in the examples, GP
The number average molecular weight and molecular weight distribution were measured by C, and NMR analysis was performed. Regarding Examples 1 and 2, a GPC chart is shown in FIG. 1 and an NMR chart is shown in FIG.

2. Evaluation of composition (1) Preparation of composition 10 parts by weight of the polymer obtained in each of Examples and Comparative Examples
After dissolving in 0 part by weight of propylene glycol monomethyl ether acetate (PGMEA), 0.2 part by weight of triphenylsulfonium triflate as a photo-acid generator was added and sufficiently dissolved. This was filtered using a PTFE filter (filtration accuracy 0.1 μm).

(2) Evaluation of photoresist performance (2-1) Sensitivity (E _OP ) After the adjusted composition was applied on a silicon wafer by a spin coater so that the film thickness after prebaking would be 0.5 μm. Prebaked at 140 ° C. for 90 seconds on a hot plate. Then, an ArF excimer laser irradiation device manufactured by ISI (lens numerical aperture 0.60, exposure wavelength 19
3 nm) and exposed through a test reticle (mask) having various line widths. Then 1 on the hot plate
After performing post exposure bake (PEB) at 40 ° C. for 90 seconds,
Paddle development was performed for 60 seconds at 23 ° C. with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. Then, it was washed with water and dried to obtain a positive pattern. At that time, an exposure amount capable of forming a line-and-space pattern having a line width of 0.18 μm (a line-space ratio of 1: 1) with a line width of 1: 1 was defined as sensitivity (E _OP ). (2-2) Resolution The minimum dimension of the photoresist pattern resolved when exposed with an exposure amount corresponding to the sensitivity obtained in (2-1) was defined as the resolution. (2-3) tan θ The exposure amount (mJ / cm ² ) is plotted on the horizontal axis and the alkali dissolution rate (nm / s) of the composition is plotted on the vertical axis, and the discrimination curve (discrimina
tion curve) was created. The slope near the inflection point of this curve is represented by tangent (tan θ).

Table 1 shows the measurement results of (2-1) to (2-3).
It was shown to.

[Table 1]

Examples 1 and 2 are two types of monomer units of A and B, and Examples 3 and 4 are polymers which are copolymerized by using three types of monomer units of A, B and C, respectively. The ratio of the monomer units was proper, and the number average molecular weight and dispersity were favorable. Then, the compositions of Examples 5 to 8 using these polymers were excellent in sensitivity and resolution. In particular, Examples 1, 3, 4
Since the polymer was synthesized by the ATRP method, the resolution was further improved. On the other hand, Comparative Example 1 is a polymer copolymerized by using two kinds of monomer units A and C, and Comparative Example 2 is a polymer copolymerized by using two kinds of monomer units B and C, respectively. The compositions of 3 and 4 were inferior in sensitivity and resolution.

[0035]

INDUSTRIAL APPLICABILITY The present invention is a polymer for a chemically amplified photoresist having a structure represented by the general formula (I) and a photoresist composition using the same. The composition of the present invention has sensitivity and resolution. It is an excellent one. Therefore, the present invention is useful as a chemically amplified photoresist polymer for ArF excimer light and a photoresist composition using the same.

[Brief description of drawings]

FIG. 1 is a GPC chart of the polymer obtained in Example 1.

FIG. 2 is an NMR chart of the polymer obtained in Example 1.

Continued front page    F-term (reference) 2H025 AA01 AA02 AA09 AA10 AB16                       AC04 AC08 AD03 BE00 BE10                       BG00 CB14 CB41 CB55 CB56                       CC03 FA17                 4J100 AL03R AL08P AL08Q AL08R                       BA04R BA11R BC03R BC04P                       BC08R BC09Q BC53R CA05                       DA00 DA01 JA38

Claims (6)

[Claims] 1. A polymer for a chemically amplified photoresist represented by the general formula (I). [Chemical 1] The general formula (I) represents a polymer obtained by copolymerizing two kinds of monomer components represented by the number of units a and b, or three kinds of monomer components represented by the number of units a, b, and c. The bonding state of the three kinds or three kinds of monomer components may be random or block. In the general formula (I), R ₁ , R ₂ , and R ₃ represent either a hydrogen atom or a methyl group, and may be the same or different. R ₄ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an alkoxyalkyl group,
Represents one of a cyclic ether group and a cyclic ester group,
You may use individually or in mixture of 2 or more types. a / (a + b + c) is 0.2 to 0.8, b / (a + b +)
c) is 0.05 to 0.5, and c / (a + b + c) is 0 to
It is 0.5. 2. The polymer for chemically amplified photoresist has a number average molecular weight (Mn) of 100 as measured by GPC.
0 to 100,000 and dispersity (Mw / Mn)
Is greater than 1.0 and less than or equal to 2.0. The polymer for chemically amplified photoresist according to claim 1. 3. The polymer for a chemically amplified photoresist according to claim 1, wherein the polymer for a chemically amplified photoresist is obtained by the ATRP method (living radical polymerization method). 4. The polymer for chemically amplified photoresist according to claim 1, wherein the polymer for chemically amplified photoresist is a block polymer. 5. A chemically amplified photoresist composition containing the following (X) to (Z) as essential components. (X) The polymer for chemically amplified photoresist according to any one of claims 1 to 4, (Y) a compound that generates an acid by the action of light, and (Z) (X), (Y) and (Z).
A solvent that dissolves. 6. The compound according to claim 5, wherein the compound (Y) that generates an acid by the action of light is 1 to 20 parts by weight based on 100 parts by weight of the (X) polymer for a chemically amplified photoresist. Chemically amplified photoresist composition.