TW201840527A - Monomer, polymer, and positive resist composition - Google Patents

Abstract

The purpose of the present invention is to provide a polymer which is capable of forming a resist pattern having excellent heat resistance and dry etching resistance when used as a main chain scission type positive resist. A monomer according to the present invention is represented by formula (I). Moreover, a polymer according to the present invention comprises a monomer unit represented by formula (II). In formulas (I) and (II), B is a bridged cyclic saturated hydrocarbon cyclic group which may have a substituent and n is 0 or 1.

Description

Monomer, polymer and positive photoresist composition

The present invention relates to a monomer, a polymer, and a positive photoresist composition, and more particularly, to a polymer suitable as a positive photoresist, a positive photoresist composition containing the polymer, and a polymer used for preparing the polymer. monomer.

In the past, in the fields of semiconductor manufacturing and the like, free radiation such as electron beams or short-wavelength light such as ultraviolet rays (including extreme ultraviolet (EUV)) were used (hereinafter, free radiation and short-wavelength light are also referred to as "free radiation"). A polymer that cuts the main chain and reduces the molecular weight by irradiation is used as a main chain-cutting positive photoresist.

Further, for example, it is reported in Patent Document 1 (Japanese Patent Publication No. S57-969) that a polymer obtained by polymerizing a specific acrylate monomer containing a halogen atom has high sensitivity to free radiation, and furthermore, By using this polymer, a photoresist pattern excellent in heat resistance and resolution and suitable for dry etching can be formed.

However, the positive photoresist made of the polymer described in Patent Document 1 is required to further improve the heat resistance and dry etching resistance of the photoresist pattern.

Accordingly, an object of the present invention is to provide a polymer capable of forming a photoresist pattern having excellent heat resistance and dry etching resistance when used as a main chain-cutting positive photoresist, and a composition of a positive photoresist containing the polymer Thing.

In order to achieve the above-mentioned object, the present inventors devoted themselves to research. Then, the present inventors have found that if a polymer formed using a specific monomer is used as a positive photoresist, a photoresist pattern having excellent heat resistance and dry etching resistance can be formed, and the present invention has been completed.

That is, the object of the present invention is to solve the above problems smoothly, and the monomer of the present invention is represented by the following formula (I): [化 1] [In formula (I), B is a bridged ring saturated cyclic hydrocarbon group which may have a substituent, and n is 0 or 1. ] As a feature.

If a polymer obtained by polymerizing a monomer represented by the above formula (I) (hereinafter referred to as "monomer (a)") is used as a main chain-cutting positive photoresist, the obtained light can be obtained. The resist pattern exhibits excellent heat resistance and dry etching resistance.

Here, in the monomer of the present invention, the aforementioned B may be an adamantyl group which may have a substituent or a nordecyl group which may also have a substituent, and the aforementioned substituent may be at least one of a methyl group and a hydroxyl group. . If B is an unsubstituted adamantyl group or an unsubstituted nordecyl group, or an adamantyl group having at least one of methyl and hydroxyl groups as a substituent or a drop of The alkyl group can fully improve the heat resistance and dry etching resistance of the photoresist pattern.

Furthermore, in the monomer of the present invention, the aforementioned substituent may be made into a hydroxyl group. If B is an unsubstituted adamantyl group or an unsubstituted nordecyl group, or an adamantyl group with a hydroxy group as a substituent or a noralkyl group with a hydroxy group as a substituent, the heat resistance of the photoresist pattern and the photoresist pattern can be sufficiently improved. Dry etching resistance.

The monomer of the present invention is preferably represented by any one of the following formulae (a-1) to (a-5). ［Chemical 2］

A polymer obtained by using at least any one of the monomers represented by the formulae (a-1) to (a-5) (hereinafter referred to as "monomers (a-1) to (a-5)") It is easy to cut the main chain when irradiating free radiation etc. (that is, the sensitivity to free radiation is high). In addition, when the polymer is used, the heat resistance and dry etching resistance of the photoresist pattern can be sufficiently improved.

In addition, an object of the present invention is to solve the above problems smoothly. The polymer of the present invention has a monomer unit (A) represented by the following formula (II): [In formula (II), B is a bridged ring saturated cyclic hydrocarbon group which may have a substituent, and n is 0 or 1. ).

If a polymer having the above-mentioned monomer unit (A) is used as the main chain-cutting positive photoresist, the obtained photoresist pattern can exhibit excellent heat resistance and dry etching resistance.

Here, in the polymer of the present invention, the aforementioned B may be made of an adamantyl group which may have a substituent or a nordecyl group which may also have a substituent, and the aforementioned substituent may be made of at least one of a methyl group and a hydroxyl group. . If B is an unsubstituted adamantyl group or an unsubstituted nordecyl group, or an adamantyl group having at least one of a methyl group and a hydroxyl group as a substituent or a drop of at least one of a methyl group and a hydroxyl group as a substituent The alkyl group can fully improve the heat resistance and dry etching resistance of the photoresist pattern.

In the monomer of the present invention, the aforementioned substituent may be used as a hydroxyl group. If B is an unsubstituted adamantyl group or an unsubstituted nordecyl group, or an adamantyl group with a hydroxy group as a substituent or a noralkyl group with a hydroxy group as a substituent, the heat resistance of the photoresist pattern and the Dry etching resistance.

The polymer of the present invention is preferably represented by any one of the following formulae (A-1) to (A-5) by the aforementioned formula (II). ［Chemical 4］

A polymer having at least any one of the monomer units (hereinafter referred to as "monomers (A-1) to (A-5)") represented by the formulae (A-1) to (A-5), Higher sensitivity to free radiation. In addition, when the polymer is used, the heat resistance and dry etching resistance of the photoresist pattern can be sufficiently improved.

Furthermore, in the polymer of the present invention, the proportion of the monomer unit (A) in the all-monomer units constituting the polymer may be 30 mol% or more.

In addition, an object of the present invention is to solve the above problems smoothly, and the positive photoresist composition of the present invention is characterized by containing any one of the above polymers and a solvent. When a positive photoresist composition containing the polymer is used, a photoresist pattern having excellent heat resistance and dry etching resistance can be formed.

According to the present invention, when used as a main chain-cutting positive photoresist, a polymer capable of forming a polymer having excellent heat resistance and dry etching resistance, and a monomer which can be used for the production of the polymer can be provided.

Furthermore, according to the present invention, a positive photoresist composition capable of forming a photoresist pattern having excellent heat resistance and dry etching resistance can be provided.

The following is a detailed description of the embodiments of the present invention.

In addition, in the present invention, the term "that may have a substituent" means "the one without a substituent or the one having a substituent".

Here, if the monomer composition containing the monomer of this invention is polymerized, the polymer of this invention which can be used as a positive photoresist can be obtained. In addition, the polymer of the present invention can be suitably used as a main chain-cutting type positive photoresist that "cuts the main chain and reduces the molecular weight by irradiation with short-wavelength light such as free radiation such as electron beams and ultraviolet rays." The positive photoresist composition of the present invention contains the polymer of the present invention as a positive photoresist, and can be used, for example, when forming a photoresist pattern in a manufacturing process of a semiconductor, a photomask, a mold, or the like.

(Monomer and polymer)

The monomer of the present invention is represented by the following formula (I): [Chem 5] [In formula (I), B is a bridged ring saturated cyclic hydrocarbon group which may have a substituent, and n is 0 or 1. ] As a feature.

Further, if a monomer composition containing the monomer of the present invention and optionally other monomers is polymerized, a monomer unit (A) represented by the following formula (II) can be obtained: [In formula (II), B and n are the same as formula (I)] The polymer of the present invention.

Furthermore, since the polymer of the present invention contains at least a specific monomer unit (A), if it is irradiated with free radiation or the like (for example, electron beam, hafnium fluoride laser, argon fluoride laser, extreme ultraviolet laser, etc.) , Will cut the main chain and reduce molecular weight. The polymer of the present invention contains a bridged ring saturated cyclic hydrocarbon group in the monomer unit (A). Although the polymer having such a bridged-ring saturated cyclic hydrocarbon group is estimated to be affected by the large and rigid structure of the bridged-ring saturated cyclic hydrocarbon group, the glass transition temperature is high, and it is difficult to use it for dry etching ions. , High-speed neutral particles, free radicals and so on. Therefore, if the polymer of the present invention is used as a main chain-cutting positive photoresist, a photoresist pattern excellent in heat resistance and dry etching resistance can be formed well.

<Single unit (A)>

Here, the monomer unit (A) contained in the polymer of the present invention is derived from the structural unit of the monomer (a) of the present invention. In addition, the proportion of the monomer unit (A) in all the monomer units constituting the polymer may be, for example, 30 mol% or more, 50 mol% or more, 70 mol% or more, and 90 mol. % Or more, it can be 100 mol%.

The so-called "bridged saturated saturated cyclic hydrocarbon group" which constitutes B in formulae (I) and (II) refers to a base composed of a ring structure having at least one bridging group as described below. The bridging group is Among the saturated cyclic hydrocarbons (the largest saturated cyclic hydrocarbons) with the most carbon atoms present in this group, two or more non-adjacent atoms are bridged groups.

Examples of the maximum saturated cyclic hydrocarbon include cyclohexane and cyclooctane.

The bridging group that connects two or more non-adjacent atoms in the largest saturated cyclic hydrocarbon is not particularly limited as long as it is a divalent group, but an alkylene group is preferred, and a methylene group is preferred.

In addition, the bridged cyclic saturated cyclic hydrocarbon group constituting B in the formulae (I) and (II) may have a substituent. The substituent that the bridged cyclic saturated cyclic hydrocarbon group has is not particularly limited, and examples thereof include methyl groups. Alkyl, hydroxy, etc. In the case where the bridged cyclic saturated cyclic hydrocarbon group has a plurality of substituents, the substituents may be the same or different. In addition, when the bridge-ring saturated cyclic hydrocarbon group has a plurality of substituents, two substituents may be bonded together to form a heterocyclic ring such as a γ-butyrolactone ring.

Here, examples of the bridged cyclic saturated cyclic hydrocarbon group which may have a substituent include, for example, an adamantyl group which may have a substituent, and a nordecyl group which may also have a substituent. In addition, from the viewpoint of improving the sensitivity of the polymer to free radiation and sufficiently improving the dry etching resistance of the photoresist pattern, as a bridge-ring saturated cyclic hydrocarbon group which may also have a substituent, an unsubstituted adamantyl group is used. Better.

Furthermore, n in the formulae (I) and (II) is preferably 0 from the viewpoint of increasing the sensitivity of the polymer to free radiation and increasing the glass transition temperature to sufficiently improve the heat resistance of the photoresist pattern.

In addition, in the case where n in formulae (I) and (II) is 0, the carbon atom constituting the bridged saturated saturated cyclic hydrocarbon group of B is not the same as the ester bond (-C (= O) -O-). From the viewpoint of improving the thermal stability of the polymer, the carbon atom to which the carbonyl oxygen atom is bonded is preferably a methyl group which does not have a substituent.

Moreover, in the formulae (I) and (II), the aforementioned B may be an adamantyl group which may have a substituent or a nordecyl group which may also have a substituent, and the aforementioned substituent may be at least a methyl group and a hydroxyl group. One. If B is an unsubstituted adamantyl group or an unsubstituted nordecyl group, or an adamantyl group having at least one of a methyl group and a hydroxyl group as a substituent or a drop of at least one of a methyl group and a hydroxyl group as a substituent The alkyl group can fully improve the heat resistance and dry etching resistance of the photoresist pattern.

In addition, in the formulae (I) and (II), the aforementioned B may be an adamantyl group which may have a substituent or a nordecyl group which may also have a substituent, and the aforementioned substituent may be a hydroxyl group. If B is an unsubstituted adamantyl group or an unsubstituted nordecyl group, or an adamantyl group with a hydroxy group as a substituent or a noralkyl group with a hydroxy group as a substituent, the heat resistance of the photoresist pattern and the photoresist pattern can be sufficiently improved. Dry etching resistance.

In addition, as the monomer (a), the following monomers (a-1) are used from the viewpoint of improving the sensitivity of the polymer to free radiation and the like, and sufficiently improving the heat resistance and dry etching resistance of the photoresist pattern. It is preferable to use at least any one of (a-5), and it is more preferable to use at least any one of (a-1) and (a-2).

［Hua 7］

That is, as the monomer unit (A) derived from the monomer (a), from the viewpoint of improving the sensitivity of the polymer to free radiation, etc., and simultaneously improving the heat resistance and dry etching resistance of the photoresist pattern, It is preferable to use at least any one of the following monomers (A-1) to (A-5), and it is more preferable to use at least any one of (A-1) and (A-2). ［Chem 8］

The method for producing the monomer (a) is not particularly limited. For example, an ester can be obtained by reacting 2,3-dichloropropionic acid with an alcohol having a bridged cyclic saturated cyclic hydrocarbon group which may also have a substituent, and hydrogen chloride can be released from the ester, thereby obtaining a monomer ( a).

〈Other monomer units〉

The polymer of the present invention may have a monomer unit other than the monomer unit (A) in addition to the monomer unit (A). The proportion of other monomer units in the all-monomer unit constituting the polymer may be, for example, 70 mol% or less, 50 mol% or less, 30 mol% or less, 10 mol% or less, or May be 0 mol%.

The other monomer units are not particularly limited, and examples thereof include structural units derived from α-methylstyrene and derivatives thereof.

Here, the weight average molecular weight of the polymer of the present invention is preferably 1,000 or more, more preferably 10,000 or more, more preferably 30,000 or more, and more preferably 1,000,000 or less, preferably 500,000 or less, and 200,000 or less. For the better.

(Method for preparing polymer)

The polymer having the above-mentioned monomer unit (A) can be prepared, for example, by polymerizing a monomer composition containing the monomer (a), and then arbitrarily refining the obtained polymer.

<Polymerization of monomer composition>

Here, as the monomer composition used in the preparation of the polymer of the present invention, a monomer (a) and a monomer component containing other monomers optionally added, an arbitrary solvent, a polymerization initiator, and an optionally added monomer may be used. Mixture of additives. The polymerization of the monomer composition can be performed by a known method. Among them, cyclopentanone is preferably used as a solvent, and a radical polymerization initiator such as azobisisobutyronitrile is preferably used as a polymerization initiator.

In addition, the polymer obtained by polymerizing the monomer composition is not particularly limited, and a good solvent such as tetrahydrofuran is added to a solution containing the polymer, and then the solution containing the good solvent is dropped into a poor solvent such as methanol. The polymer is coagulated and recovered.

<Refining of polymers>

The purification method used when refining the obtained polymer is not particularly limited, and examples thereof include known methods such as a reprecipitation method and a column chromatography method. Among them, as the refining method, reprocessing is used. Precipitation is preferred.

In addition, the refining of the polymer can be carried out repeatedly.

Furthermore, for refining a polymer by a reprecipitation method, for example, it is preferable that the obtained polymer is dissolved in a good solvent such as tetrahydrofuran, and then the obtained solution is dropped to the good solvent such as tetrahydrofuran and methanol In a mixed solvent such as a poor solvent, the polymer is precipitated.

In the case of refining a polymer by a reprecipitation method, as the polymer of the present invention, a polymer precipitated from a mixed solvent of a good solvent and a poor solvent may be used, or a polymer not precipitated from a mixed solvent ( That is, a polymer dissolved in a mixed solvent). Here, the polymer not precipitated from the mixed solvent can be recovered from the mixed solvent by a known method such as concentration and drying.

(Positive Photoresist Composition)

The positive photoresist composition of the present invention contains the above-mentioned polymer and solvent, and more optionally contains known additives to be incorporated in the photoresist composition. In addition, the positive photoresist composition of the present invention contains the polymer as a positive photoresist. Therefore, if the positive photoresist composition of the present invention is used to form a photoresist pattern, heat resistance and dry etching resistance can be formed. Excellent photoresist pattern.

<Solvent>

The solvent is not particularly limited as long as it is a solvent capable of dissolving the polymer. For example, a known solvent such as a solvent described in Japanese Patent No. 5938536 can be used. Among them, from the viewpoint of obtaining a positive photoresist composition with a moderate viscosity to improve the coating property of the positive photoresist composition, anisole, propylene glycol monomethyl ether acetate (PGMEA), and cyclopentanone are used as solvents. Cyclohexanone or methyl 3-methoxypropionate is preferred.

『Examples』

Although the present invention will be specifically described below based on examples, the present invention is not limited to these examples. In addition, in the following description, unless otherwise specified, the "%" and "part" of the quantity are based on quality.

In the examples and comparative examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer, the glass transition temperature (heat resistance), and the sensitivity, as well as the dry etching resistance of the photoresist pattern, It is measured and evaluated by the following method.

<Weight average molecular weight (Mw) and number average molecular weight (Mn)>

The weight average molecular weight (Mw) and the number average molecular weight (Mn) are connected to TSKgel G4000HXL, TSKgel G2000HXL, and TSKgel G1000HXL (all manufactured by TOSOH) as columns using gel permeation chromatography (TOSOH, HLC-8220) Alternatively, it can be determined as a standard polystyrene conversion value using tetrahydrofuran or dimethylformamide as a developing solvent.

<Glass transition temperature (heat resistance)>

About 25 mg of the obtained polymer was subjected to a differential scanning calorimeter (manufactured by Hitachi Advanced Technologies, DSC7000) in a nitrogen gas flow in a range from 40 ° C to 240 ° C twice at a rising temperature of 10 ° C / min. Measure. The intersection of the reference line of the DSC curve measured in the second measurement and the tangent of the inflection point was used as the glass transition temperature (° C) and evaluated in accordance with the following criteria. The higher the glass transition temperature of the polymer, the higher the heat resistance of the obtained photoresist pattern. A: The glass transition temperature exceeds 150 ° C. B: The glass transition temperature is above 130 ° C and below 150 ° C. C: The glass transition temperature is below 130 ° C.

<Sensitivity>

First, the number average molecular weight (Mn0) of the obtained polymer was measured. Furthermore, 0.5 g of a polymer sample taken from the obtained polymer was sealed in a glass test tube in a nitrogen gas stream. Next, the polymer sample was irradiated with γ-rays (cobalt-60 as a radiation source) at four intensity levels (40 kGy, 80 kGy, 120 kGy, 160 kGy), and the polymer sample after γ-ray irradiation was dissolved in Tetrahydrofuran or dimethylformamide was used to measure the number average molecular weight (Mn) after γ-ray irradiation.

Then, from each measurement value (Mn0, Mn) and the following formula (1), "Gs (the number of bonds to be cut when absorbing energy of 100 eV)" was calculated. Specifically, the "reciprocal of the number average molecular weight of the polymer (1 / Mn)" is taken as the vertical axis, and the "γ-ray absorption (Gy)" is plotted on the horizontal axis. "(1 / Mn)" was used to calculate "Gs", and the sensitivity was evaluated according to the following criteria. The larger the value of Gs, the higher the sensitivity. A: Gs is more than 2.0 B: Gs is 1.5 or more and 2.0 or less C: Gs is less than 1.5.

[Number 1] Mn: number average molecular weight after γ-ray irradiation Mn0: number average molecular weight before γ-ray irradiation D: γ-ray absorption (Gy)

<Dry Etching Resistance>

The polymer was dissolved in cyclopentanone, and filtered through a 0.25 μm polyethylene filter to obtain a positive photoresist composition (polymer concentration: 2.5% by mass). The obtained positive photoresist composition was rotated by using The coater was coated on a 4-inch diameter silicon wafer and heated on a hot plate at 180 ° C for 3 minutes to form a photoresist film with a thickness of about 150 nm. Measure the thickness T0 (nm) of the photoresist film. Next, a silicon wafer with a photoresist film is introduced into a sputtering device, and reverse sputtering is performed with an oxygen plasma for one minute. Measure the film thickness T1 (nm) after reverse sputtering. Then, the film reduction rate = T0-T1 (amount of film reduction per minute, unit: nm / min) was calculated, and the dry etching resistance was evaluated according to the following criteria. The smaller the value of the film reduction ratio, the higher the dry etching resistance. A: Film reduction rate is less than 23 nm / min B: Film reduction rate is 23 nm / min or more, and less than 26 nm / min C: Film reduction rate is 26 nm / min or more

(Example 1)

<Synthesis of monomer (a-1)>

In a three-necked flask equipped with a Dean-Stark apparatus, under a nitrogen flow, 56.3 g of 2,3-dichloropropionic acid, 50.0 g of 1-adamantanol, and di-2,4, pentafluorobenzenesulfonic acid were added. After 1.9 g of 6-trimethylammonium salt and 200 ml of toluene, the temperature was raised, and the reaction was performed at 80 ° C. for 12 hours and 110 ° C. for 5 hours for 17 hours, and the generated water was distilled off.

After the reaction solution was cooled to room temperature, 300 mL of hexane was added to cool to 0 ° C. Subsequently, 50 g of triethylamine was slowly dropped, and the temperature was raised to room temperature to perform a reaction for 5 hours. The precipitated salt was filtered through a Tongshan funnel, and the salt was washed twice with 50 ml of hexane. The filtrate and washing solution were subjected to liquid separation operation twice with 1 M hydrochloric acid, twice with a saturated aqueous sodium hydrogen carbonate solution, and twice with a saturated saline solution. Anhydrous magnesium sulfate was added to the organic layer, followed by filtration, and the filtrate was concentrated by an evaporator. Hexane was added to the concentrate, and the mixture was heated to 60 ° C to dissolve it, and then cooled to 0 ° C to precipitate crystals. The crystals were filtered through a Tongshan funnel and dried under reduced pressure at room temperature for 24 hours to obtain a monomer (a-1) having a structure of the following formula.

［Hua 9］ (a-1)

(Synthesis of Polymer 1)

In a glass ampule placed in a stirrer, 1.00 g of monomer (a-1), 0.0136 g of azobisisobutyronitrile as a monomer polymerization initiator, and 4.00 g of cyclopentanone as a solvent were added to Sealed, and then repeatedly pressurized and decompressed 10 times with nitrogen to remove oxygen from the system.

Then, the system was warmed to 78 ° C, and a reaction was performed for 6 hours. Next, 10 g of tetrahydrofuran was added to the system, and the obtained solution was dropped into 300 mL of methanol to precipitate a polymer. After that, the precipitated polymer was recovered by filtration, and then dissolved in 10 g of tetrahydrofuran. The obtained solution was dropped into 300 mL of methanol, and the precipitate formed was collected by filtration, and the pressure was reduced at 50 ° C. By drying for 24 hours, a polymer 1 having a monomer unit (A-1) of 100% or less in the total monomer units was obtained.

［Chem10］ (A-1)

The weight average molecular weight of the obtained polymer 1 was 61,000, and the molecular weight distribution (Mw / Mn) was 3.62. The obtained polymer 1 was then used to evaluate its glass transition temperature (heat resistance), sensitivity, and dry etching resistance. The results are shown in Table 1.

(Example 2)

<Synthesis of monomer (a-2)>

In a three-necked flask equipped with a Dean-Stark device, under a nitrogen flow, 56.3 g of 2,3-dichloropropionic acid, 50.0 g of 2-adamantanol, and di-2,4,5 After 1.9 g of 6-trimethylammonium salt and 200 ml of toluene, the temperature was raised to 120 ° C., and the reaction was performed for 24 hours, and the generated water was distilled off at the same time.

After the reaction solution was cooled to room temperature, 300 mL of hexane was added to cool to 0 ° C. Subsequently, 50 g of triethylamine was slowly dropped, and the temperature was raised to room temperature to perform a reaction for 5 hours. The precipitated salt was filtered through a Tongshan funnel, and the salt was washed twice with 50 mL of hexane. The filtrate and washing solution were separated with 1 M hydrochloric acid twice, twice with a saturated sodium bicarbonate aqueous solution, and twice with a saturated saline solution. Anhydrous magnesium sulfate was added to the organic layer, followed by filtration, and the filtrate was concentrated by an evaporator. Hexane was added to the concentrate, and the mixture was heated to 60 ° C to dissolve it, and then cooled to 0 ° C to precipitate crystals. The crystals were filtered through a Tongshan funnel and dried under reduced pressure at room temperature for 24 hours to obtain a monomer (a-2) having the following structure.

［Chem 11］ (A-2)

<Synthesis of Polymer 2>

In a glass ampule that has been placed in a stirrer, 1.00 g of monomer (a-2), 0.0136 g of azobisisobutyronitrile as a polymerization initiator, and 4.00 g of cyclopentanone as a solvent are added and sealed. The nitrogen was repeatedly pressurized and decompressed 10 times to remove oxygen in the system.

Then, the system was warmed to 78 ° C, and a reaction was performed for 6 hours. Next, 10 g of tetrahydrofuran was added to the system, and the obtained solution was dropped into 300 mL of methanol to precipitate a polymer. After that, the precipitated polymer was recovered by filtration, and then dissolved in 10 g of tetrahydrofuran. The obtained solution was dropped into 300 mL of methanol, and the precipitate formed was collected by filtration, and the pressure was reduced at 50 ° C. By drying for 24 hours, a polymer 2 having a monomer unit (A-2) of 100% or less in the total monomer units was obtained.

［Hua 12］ (A-2)

The weight average molecular weight of the obtained polymer 2 was 38,000, and the molecular weight distribution (Mw / Mn) was 2.79. The obtained polymer 2 was then used to evaluate its glass transition temperature (heat resistance), sensitivity, and dry etching resistance. The results are shown in Table 1.

(Example 3)

<Synthesis of monomer (a-3)>

In a three-necked flask equipped with a Dean-Stark device, under a nitrogen flow, 25.3 g of 2,3-dichloropropionic acid, 24.5 g of 1-adamantane methanol, and di-2,4, pentafluorobenzenesulfonic acid were added. After 0.7 g of 6-trimethylammonium salt and 100 mL of toluene, the temperature was raised, and the reaction was performed at 80 ° C. for 12 hours and 130 ° C. for 4 hours for 16 hours, and the generated water was distilled off.

After the reaction solution was cooled to room temperature, 150 mL of hexane was added to cool to 0 ° C. Subsequently, 22.5 g of triethylamine was slowly dropped, and the temperature was raised to room temperature to perform a reaction for 5 hours. The precipitated salt was filtered through a Tongshan funnel, and the salt was washed twice with 50 mL of hexane. The filtrate and washing solution were subjected to liquid separation operation twice with 1 M hydrochloric acid, twice with a saturated sodium bicarbonate aqueous solution, and twice with saturated saline. Anhydrous magnesium sulfate was added to the organic layer, followed by filtration, and the filtrate was concentrated by an evaporator. A small amount of hexane was added to the concentrate, and it was filtered through a Tongshan funnel and dried under reduced pressure at room temperature for 24 hours to obtain a monomer (a-3) having a structure of the following formula.

［Chemical 13］ (A-3)

(Synthesis of Polymer 3)

In a glass ampule placed in a stirrer, 1.00 g of monomer (a-3), 0.0129 g of azobisisobutyronitrile as a polymerization initiator, and 4.00 g of cyclopentanone as a solvent were added and sealed. The nitrogen was repeatedly pressurized and decompressed 10 times to remove oxygen in the system.

Then, the system was warmed to 78 ° C, and a reaction was performed for 6 hours. Next, 10 g of tetrahydrofuran was added to the system, and the obtained solution was dropped into 300 mL of methanol to precipitate a polymer. After that, the precipitated polymer was recovered by filtration, and then dissolved in 10 g of tetrahydrofuran. The obtained solution was dropped into 300 mL of methanol, and the precipitate formed was collected by filtration, and the pressure was reduced at 50 ° C. By drying for 24 hours, a polymer 3 having a monomer unit (A-3) of 100% or less in the total monomer units was obtained.

［Chem 14］ (A-3)

The weight average molecular weight of the obtained polymer 3 was 30,600, and the molecular weight distribution (Mw / Mn) was 2.76. The obtained polymer 3 was then used to evaluate its glass transition temperature (heat resistance), sensitivity, and dry etching resistance. The results are shown in Table 1.

(Example 4)

<Synthesis of monomer (a-4)>

In a three-necked flask equipped with a Dean-Stark device, under nitrogen flow, 38.6 g of 2,3-dichloropropionic acid, 50.0 g of isoalcohol, and di-2,4,6-trifluorobenzenesulfonic acid were added. After 1.4 g of tolyl ammonium salt and 200 mL of toluene, the temperature was raised, and the reaction was performed at 110 ° C. to 130 ° C. for 12 hours while distilling off the generated water.

After the reaction solution was cooled to room temperature, 300 mL of hexane was added to cool to 0 ° C. Subsequently, 50 g of triethylamine was slowly dropped, and the temperature was raised to room temperature to perform a reaction for 5 hours. The precipitated salt was filtered through a Tongshan funnel, and the salt was washed twice with 50 mL of hexane. The filtrate and washing solution were subjected to liquid separation operation twice with 1 M hydrochloric acid, twice with a saturated sodium bicarbonate aqueous solution, and twice with saturated saline. Anhydrous magnesium sulfate was added to the organic layer, followed by filtration, and the filtrate was concentrated by an evaporator. The concentrate was distilled under reduced pressure to obtain a monomer (a-4) having the following structure.

[Chemized 15] (A-4)

<Synthesis of Polymer 4>

In a glass ampule that has been placed in a stirrer, 1.00 g of the monomer (a-4), 0.0108 g of azobisisobutyronitrile as a polymerization initiator, and 4.00 g of cyclopentanone as a solvent are added and sealed. The nitrogen was repeatedly pressurized and decompressed 10 times to remove oxygen in the system.

Then, the system was warmed to 78 ° C, and a reaction was performed for 6 hours. Next, 10 g of tetrahydrofuran was added to the system, and the obtained solution was dropped into 300 mL of methanol to precipitate a polymer. After that, the precipitated polymer was recovered by filtration, and then dissolved in 10 g of tetrahydrofuran. The obtained solution was dropped into 300 mL of methanol, and the precipitate formed was collected by filtration, and the pressure was reduced at 50 ° C. By drying for 24 hours, a polymer 4 having a monomer unit (A-4) of 100% or less in the total monomer units was obtained.

［Hua 16］ (A-4)

The weight average molecular weight of the obtained polymer 4 was 31,000, and the molecular weight distribution (Mw / Mn) was 1.74. The obtained polymer 4 was then used to evaluate its glass transition temperature (heat resistance), sensitivity, and dry etching resistance. The results are shown in Table 1.

(Example 5)

<Synthesis of monomer (a-5)>

In a three-necked flask equipped with a Dean-Stark apparatus, under a stream of nitrogen, 27.8 g of 2,3-dichloropropionic acid, 25.0 g of hydroxynorbornyl, and di-2,4, pentafluorobenzenesulfonic acid were added. After 1.0 g of 6-trimethylammonium salt and 150 mL of toluene, the temperature was raised to 130 ° C., and the reaction was performed for 24 hours, and the generated water was distilled off at the same time.

After the reaction solution was cooled to room temperature, 150 mL of diethyl ether was added to cool to 0 ° C. Subsequently, 24.6 g of triethylamine was slowly dropped, and the temperature was raised to room temperature to perform a reaction for 5 hours. The precipitated salt was filtered through a Tongshan funnel, and the salt was washed twice with 25 mL of ether. The filtrate and washing solution were subjected to liquid separation operation twice with 1 M hydrochloric acid, twice with a saturated sodium bicarbonate aqueous solution, and twice with saturated saline. Anhydrous magnesium sulfate was added to the organic layer, followed by filtration, and the filtrate was concentrated by an evaporator. The concentrate was dissolved in a small amount of tetrahydrofuran, and then poured into a large amount of hexane to obtain a precipitate. The precipitate was recovered by filtration and dried under reduced pressure at room temperature for 24 hours to obtain a monomer (a-5) having a structure of the following formula.

［Hua 17］ (A-5)

<Synthesis of Polymer 5>

In a glass ampule placed in a stirrer, 1.00 g of monomer (a-5), 0.0136 g of azobisisobutyronitrile as a polymerization initiator, and 4.00 g of cyclopentanone as a solvent were added and sealed. The nitrogen was repeatedly pressurized and decompressed 10 times to remove oxygen in the system.

Then, the system was warmed to 78 ° C, and a reaction was performed for 6 hours. Next, 10 g of tetrahydrofuran was added to the system, and the obtained solution was dropped into 300 mL of methanol to precipitate a polymer. After that, the precipitated polymer was recovered by filtration, and then dissolved in 10 g of tetrahydrofuran. The obtained solution was dropped into 300 mL of methanol, and the precipitate formed was collected by filtration, and the pressure was reduced at 50 ° C. By drying for 24 hours, a polymer 5 having a monomer unit (A-5) ratio of 100% or less in the total monomer units was obtained.

［Hua 18］ (A-5)

The weight average molecular weight of the obtained polymer 5 was 109,600, and the molecular weight distribution (Mw / Mn) was 3.80. The obtained polymer 5 was then used to evaluate its glass transition temperature (heat resistance), sensitivity, and dry etching resistance. The results are shown in Table 1.

(Comparative Example 1)

<Synthesis of Polymer 6>

In a glass ampule placed in a stirrer, 5.00 g of α-chloroacrylic acid-2,2,2-trifluoroethyl ester, 0.087 g of azobisisobutyronitrile as a polymerization initiator, and 5.00 g of cyclopentanone was sealed, and then repeatedly pressurized and decompressed with nitrogen 10 times to remove oxygen in the system.

Then, the system was warmed to 78 ° C, and a reaction was performed for 6 hours. Next, 10 g of tetrahydrofuran was added to the system, and the obtained solution was dropped into 500 mL of methanol to precipitate a polymer. Then, the precipitated polymer was recovered by filtration, and then dissolved in 10 g of tetrahydrofuran. The obtained solution was dropped into 500 mL of methanol, and the precipitate formed was collected by filtration, and the pressure was reduced at 50 ° C. The polymer was dried for 24 hours to obtain a polymer 6 having a ratio of α-chloroacrylic acid-2,2,2-trifluoroethyl units in all monomer units of 100%.

The weight average molecular weight of the obtained polymer 6 was 54,000, and the molecular weight distribution (Mw / Mn) was 1.90. The obtained polymer 6 was then used to evaluate its glass transition temperature (heat resistance), sensitivity, and dry etching resistance. The results are shown in Table 1.

"Table 1"

From Table 1, it can be seen that the polymers of Examples 1 to 5 with monomer (A) can improve the heat resistance and dry type of the photoresist pattern more than the polymer of Comparative Example 1 without monomer (A). Etching resistance.

According to the present invention, it is possible to provide a polymer capable of forming a photoresist pattern having excellent heat resistance and dry etching resistance when used as a main chain-cutting positive photoresist, and a monomer capable of being used for the production of the polymer. .

Furthermore, according to the present invention, a positive photoresist composition capable of forming a photoresist pattern having excellent heat resistance and dry etching resistance can be provided.

no.

no.

Claims (10)

A monomer represented by the following formula (I): [化 1] [In formula (I), B is a bridged ring saturated cyclic hydrocarbon group which may have a substituent, and n is 0 or 1]. The monomer according to claim 1, wherein the B is an adamantyl group which may have a substituent or a noralkyl group which may also have a substituent, and the substituent is at least one of a methyl group and a hydroxyl group. The monomer according to claim 2, wherein the substituent is a hydroxyl group. The monomer according to claim 1, which is represented by any one of the following formulae (a-1) to (a-5): [Chem 2] . A polymer having a monomer unit (A) represented by the following formula (II): [Chem. 3] [In formula (II), B is a bridged ring saturated cyclic hydrocarbon group which may have a substituent, and n is 0 or 1]. The polymer according to claim 5, wherein B is an adamantyl group which may have a substituent or a noralkyl group which may also have a substituent, and the substituent is at least one of a methyl group and a hydroxyl group. The polymer according to claim 6, wherein the substituent is a hydroxyl group. The polymer according to claim 5, which is represented by any one of the following formulae (A-1) to (A-5): [Chem 4] . The polymer according to claim 5, wherein the proportion of the monomer units (A) in all the monomer units constituting the polymer is 30 mol% or more. A positive photoresist composition containing the polymer and a solvent according to any one of claims 5 to 9.