KR100585067B1 - Photosensitive polymer having cyclic backbone and photosensitive copolymer including the polymer - Google Patents

Abstract

Disclosed are a photosensitive polymer having a backbone having an annular structure and containing an alicyclic compound, a photosensitive copolymer comprising the same, and a resist composition obtained therefrom. The photosensitive polymer which concerns on this invention has a following formula, and a weight average molecular weight is 3,000-100,000.

Wherein R, R _1, R ₂ are each ethyl or methoxy group hydrogen, methyl,, R ₃ is a saturated aliphatic or alicyclic compound of a C ₁ ~C _20.

Description

Photosensitive polymer having a cyclic structure of a backbone and a photosensitive copolymer comprising the same {Photosensitive polymer having cyclic backbone and photosensitive copolymer including the polymer}

The present invention relates to a chemically amplified resist composition, and more particularly, to a photosensitive polymer having a backbone having a cyclic structure, a photosensitive copolymer comprising the same, and a resist composition for an ArF excimer laser obtained therefrom.

As the semiconductor manufacturing process becomes complicated and the degree of integration of semiconductor devices increases, fine pattern formation is required. Moreover, in devices with a semiconductor device having a capacity of 1 gigabit or more, a pattern size of 0.2 μm or less is required for the design rule, and thus there is a limit to using a resist material using a conventional KrF excimer laser (248 nm). have. Thus, a lithography technique using ArF excimer laser (193 nm), a new energy exposure source, has emerged.

Such a resist material used in lithography using an ArF excimer laser has many problems to be commercialized compared to conventional resist materials. The most representative problem is the polymer's transmittance and resistance to dry etching.

Acrylic or methacrylic polymers have been mainly used as a general ArF resist known to date. Among them, poly (methyl methacrylate-tert -butyl methacrylate-methacrylic acid) which is an initial terpolymer system of IBM Corporation is representative. A serious problem with these polymers is their poor resistance to dry etching.

Accordingly, in order to increase the resistance to dry etching, an alicyclic compound, for example, an isobornyl group, adamantyl group, or tricyclo, which is a material having strong resistance to dry etching The introduction of the decycloyl group (tricyclodecanyl group) into the backbone of the polymer is also used. However, they are still poorly resistant to dry etching.

Accordingly, an object of the present invention is to provide a photosensitive polymer containing an alicyclic compound while the backbone of the polymer has a cyclic structure so that resistance to dry etching can be sufficiently secured. will be.

Another object of the present invention is to provide photosensitive copolymers comprising the polymer.

It is still another object of the present invention to provide a resist composition comprising the photosensitive polymer described above so as to enhance resistance to dry etching in a lithography process using an ArF excimer laser.

In order to achieve the above object, the present invention has the following formula, and provides a photosensitive polymer having a weight average molecular weight of 3,000 to 100,000.

Wherein R, R _1, R ₂ are each ethyl or methoxy group hydrogen, methyl,, R ₃ is a saturated aliphatic or alicyclic compound of a C ₁ ~C _20.

Preferably, R ₃ is an adamantyl group, adamantylmethyl group, norbornyl group, norbornylmethyl group, isobornyl group, menthyl group, isomentyl group, methyl group or ethyl group.

In order to achieve the above another object, the present invention is selected from the group consisting of the photosensitive polymer defined above and norbornene and (meth) acrylate derivatives having an alcohol, carboxylic acid, tert-butyl, or isobornyl group The photosensitive copolymer which consists of either and consists of comonomers contained in the quantity of 1-30 mol% is provided.

The weight average molecular weight of the said photosensitive copolymer is 3,000-100,000.

For example, norborneneol, norbornenemethanol, norbornenecarboxylic acid, 2-hydroxyethyl 5-norbornene-2-carboxylate, or tert-butyl 5-norbornene-as the comonomer 2-carboxylate may be used, in which case the comonomer may be contained in an amount of 3 to 20 mole percent in the copolymer.

Alternatively, 2-hydroxyethyl (meth) acrylate, tert-butyl (meth) acrylate, or isobornyl (meth) acrylate may be used as the comonomer, in which case the comonomer is used as the copolymer. It may be contained in an amount of 3 to 30 mol% within.

In order to achieve the above another object, the present invention provides a resist composition consisting of the photosensitive polymer as defined above, a photoacid generator (PAG), and an organic base.

The amount of the PAG in the resist composition is 1 to 15% by weight based on the weight of the photosensitive polymer, and the amount of the organic base is 0.01 to 2% by weight based on the weight of the photosensitive polymer.

As the PAG, triarylsulfonium salts, diaryliodonium salts or sulfonates can be used.

Triethylamine, triisobutylamine, triisooctylamine, diethanolamine or triethanolamine can be used as the organic base.

According to the present invention, a sufficient resistance to dry etching can be ensured by providing a photosensitive polymer containing an alicyclic compound while the backbone has a cyclic structure.

Next, preferred embodiments of the present invention will be described in detail.

Example 1

Synthesis of 1-chloromethyl adamantyl ether

In a round flask, sodium hydride (4.8 g, 55% NaH) and 1-adamantanol (15 g, 0.1 mole) were reacted in anhydrous THF (tetrahydrofuran) (150 mL), followed by excess bromo Chloromethane (0.4 mol) was slowly dropped and reacted at room temperature for about 12 hours.

After the reaction was completed, excess THF was volatilized and the reaction was poured into excess water and neutralized with HCl. Thereafter, the mixture was extracted using diethyl ether, and then dried using MgSO ₄ .

After distilling off the solvent, diethyl ether, the product was recovered from the crude product by vacuum distillation (yield 70%).

Example 2

Synthesis of 2-chloropropyl-1-adamantyl ether

After reacting sodium hydride (4.8 g, 55% NaH) with 1-adamantanol (15 g, 0.1 mol) in anhydrous THF (150 mL), 2,2-dichloropropane (45 g, 0.4 mol) was slowly added thereto. Then, the reaction was performed at a temperature of about 45 ° C. for about 12 hours.

After the reaction was completed, the product was recovered in the same manner as in Example 1 (yield 70%).

Example 3

Synthesis of 1-adamantyloxymethyl 5-norbornene-2-carboxylate

In a round flask, 5-norbornene-2-carboxylic acid (0.11 mol) and triethylamine (0.12 mol) were reacted in methylene chloride (150 mL), followed by 1-chloromethyl adamantyl ether (0.1 mol). ) Was slowly dropped and the resulting mixture was reacted at reflux for about 12 hours.

After the reaction was completed, the reaction was poured into excess water and neutralized with HCl. Thereafter, the mixture was extracted using methylene chloride, and purified using Colum chromatography (ethyl acetate: hexane = 1: 3) to recover the product (yield 85%).

Example 4

Synthesis of 2-adamantyloxypropyl 5-norbornene-2-carboxylate

5-norbornene-2-carboxylic acid (0.11 mol) and triethylamine (0.12 mol) were reacted in methylene chloride (150 mL), followed by 2-chloropropyl-1-adamantyl ether (0.1 mol). Was slowly dropped, and the obtained mixture was reacted at room temperature for about 12 hours.

After the reaction was completed, the product was recovered in the same manner as in Example 3 (yield 80%).

Example 5

Synthesis of Menthyloxymethyl 5-norbornene-2-carboxylate

After reacting in the same manner as in Example 3 using chloromethyl menthyl ether (0.1 mol), the product was recovered (yield 75%).

Example 6

Synthesis of Copolymer

The monomer (15 g, 50 mmol) and maleic anhydride (4.9 g, 50 mmol) synthesized in Example 3 were dissolved in dioxane anhydride (8 g) together with AIBN (azobis (isobutyronitrile)) (0.17 g), followed by an ampoule. The degassing was performed by the freezing method. The reaction was then polymerized at a temperature of 70 ° C. for about 24 hours.

After the polymerization was completed, the reactant was precipitated by slowly dropping the excess in n-hexane, and the precipitate was dissolved in THF again and reprecipitated in a co-solvent (n-hexane: isopropyl alcohol = 8: 2). Was carried out to obtain a polymer (yield 40%).

At this time, the weight average molecular weight (Mw) of the obtained product was 13,600, and polydispersity was 1.8.

Example 7

Synthesis of Copolymer

The monomer (50 mmol) synthesized in Example 4 and maleic anhydride (50 mmol) were polymerized in the same manner as in Example 6, and then a polymer was obtained using the same reprecipitation method.

At this time, the weight average molecular weight (Mw) of the obtained product was 12,700, and polydispersity was 1.9.

Example 8

Synthesis of Copolymer

The monomer (50 mmol) synthesized in Example 5 and maleic anhydride (50 mmol) were polymerized in the same manner as in Example 6, and then a polymer was obtained using the same reprecipitation method.

At this time, the weight average molecular weight (Mw) of the obtained product was 13,200, and polydispersity was 1.8.

Example 9

Synthesis of Terpolymer

Example 9-1

Synthesis of Terpolymer (R _One , R ₂ = Hydrogen, R ₃ Adamantyl, R ₄ Hydroxymethyl)

The monomer synthesized in Example 3 (45 mmol), maleic anhydride (50 mmol), and 5-norbornene-2-methanol (5 mmol) with AIBN (1 mol%) were dioxane anhydride (× 0.5 times). After dissolving in, it was degassed by the freezing method using an ampoule and the reaction was polymerized at a temperature of 70 ° C. for about 24 hours.

After the polymerization was completed, the reactant was precipitated by slowly dropping the excess in n-hexane, and the precipitate was dissolved in THF again, and reprecipitated in an auxiliary solvent (n-hexane: isopropyl alcohol = 9: 1) to prepare the polymer. Obtained (yield 40%).

At this time, the weight average molecular weight (Mw) of the obtained product was 12,500, and polydispersity was 1.9.

Example 9-2

Synthesis of Terpolymer (R _One , R ₂ = Hydrogen, R ₃ Adamantyl, R ₄ Carboxylic acid)

After the monomer (50 mmol) synthesized in Example 3, maleic anhydride (55 mmol) and 5-norbornene-2-carboxylic acid (5 mmol) were polymerized in the same manner as in Example 9-1, Reprecipitation was carried out in the same manner as in Example 9-1, to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 12,800, and polydispersity was 2.0.

Example 9-3

Synthesis of terpolymer (R ₁ , R ₂ = hydrogen, R ₃ = adamantyl, R ₄ = 2-hydroxyethyloxycarbonyl )

Monomer (45 mmol) synthesized in Example 3, maleic anhydride (50 mmol) and 2-hydroxyethyl 5-norbornene-2-carboxylate (5 mmol) were prepared in the same manner as in Example 9-1. After the polymerization, the polymer was reprecipitated in the same manner as in Example 9-1 to obtain a polymer.

Example 9-4

Synthesis of terpolymer (R ₁ , R ₂ = methyl, R ₃ = adamantyl, R ₄ = 2-hydroxyethyloxycarbonyl )

Monomer (35 mmol) synthesized in Example 4, maleic anhydride (50 mmol), and 2-hydroxyethyl 5-norbornene-2-carboxylate (15 mmol) were prepared in the same manner as in Example 9-1. After the polymerization, the polymer was reprecipitated in the same manner as in Example 9-1 to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 11,900, and polydispersity was 1.9.

Example 9-5

Synthesis of terpolymers (R ₁ , R ₂ = hydrogen, R ₃ = mentyl, R ₄ = hydroxy )

After the polymerization of the monomer (40 mmol) synthesized in Example 5, maleic anhydride (50 mmol) and 5-norbornene-2-ol (10 mmol) in the same manner as in Example 9-1, Reprecipitation was carried out in the same manner as in 9-1 to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 12,300, and polydispersity was 1.8.

Example 9-6

Synthesis of terpolymers (R ₁ , R ₂ = hydrogen, R ₃ = mentyl, R ₄ = hydroxy )

Monomer (40 mmol) synthesized in Example 5, maleic anhydride (50 mmol) and 2-hydroxyethyl 5-norbornene-2-carboxylate (10 mmol) were prepared in the same manner as in Example 9-1. After the polymerization, the polymer was reprecipitated in the same manner as in Example 9-1 to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 12,300, and polydispersity was 1.8.

Example 10

Synthesis of Terpolymer

Example 10-1

Synthesis of Terpolymer (R _One , R ₂ , R ₄ = Hydrogen, R ₃ Adamantyl, R ₅ Hydroxyethyl)

After the polymerization of the monomer (50 mmol) synthesized in Example 3, maleic anhydride (50 mmol) and 2-hydroxyethyl acrylate (10 mmol) in the same manner as in Example 9-1, Example 9- Reprecipitation was carried out in the same manner as in 1 to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 13,300, and polydispersity was 2.1.

Example 10-2

Synthesis of Terpolymer (R _One , R ₂ = Hydrogen, R ₃ Adamantyl, R ₄ = Methyl, R ₅ = Hydrogen)

The monomer (50 mmol) synthesized in Example 3, maleic anhydride (50 mmol) and methacrylic acid (5 mmol) were polymerized in the same manner as in Example 9-1, and then the same as in Example 9-1. Reprecipitation was carried out by the method to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 14,300, and polydispersity was 2.2.

Example 10-3

Synthesis of Terpolymer (R _One , R ₂ , R ₄ = Hydrogen, R ₃ = Mentyl, R ₅ Hydroxyethyl)

Example 9- After polymerization of the monomer (40 mmol) synthesized in Example 5, maleic anhydride (50 mmol) and 2-hydroxyethyl acrylate (10 mmol) in the same manner as in Example 9-1, Reprecipitation was carried out in the same manner as in 1 to obtain a polymer.

At this time, the weight average molecular weight (Mw) of the obtained product was 14,300, and polydispersity was 2.2.

Example 11

Synthesis of Tetrapolymer

Monomer (30 mmol) synthesized in Example 3, maleic anhydride (50 mmol), 2-hydroxyethyl 5-norbornene-2-carboxylate (10 mmol) and norbornene (10 mmol) It was dissolved in dioxane anhydride (× 0.5 fold) with AIBN (1 mol%), and then degassed by freezing method using ampoules, and the reaction was polymerized at a temperature of 70 ° C. for about 24 hours.

After the polymerization, the reactant was precipitated by slowly dropping the excess in n-hexane, and then the precipitate was dissolved in THF again and reprecipitated in an auxiliary solvent (n-hexane: diethyl ether = 7: 3) to polymerize. Obtained (yield 40%).

At this time, the weight average molecular weight (Mw) of the obtained product was 13,500, and polydispersity was 1.9.

Example 12

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Resist Compositions for Pattern Forming Process

The polymers synthesized in Examples 6 to 11 (1.0 g) were mixed with propylene glycol monomethyl ether acetate (PGMEA) with triphenylsulfonium triflate (20 mg) as PAG and triisobutylamine (2 mg) as organic base. (6.0 g) completely dissolved in solution. Thereafter, the solution was filtered using a 0.2 μm membrane filter to obtain a resist composition. Thereafter, a silicon wafer having a lower film quality formed of a silicon oxide film on the upper surface thereof is prepared, the silicon wafer is treated with hexamethyldisilazane (HMDS), and then the resist composition is applied to the silicon oxide film on the silicon wafer. Coated to a thickness of 0.4 μm.

The wafer coated with the resist composition is pre-baked for 60 to 120 seconds in a temperature range of 100 to 130 ° C., and has a KrF excimer laser having a numerical aperture (NA) of 0.45 or a numerical aperture (NA) of 0.6. After exposure using an ArF excimer laser, PEB (post-exposure baking) was performed for 60 to 120 seconds at a temperature range of 100 to 140 ° C.

Thereafter, development was performed for about 20 to 60 seconds using a 2.38 wt% tetramethylammonium hydroxide (TMAH) solution. The resulting resist pattern was used as a mask, and the lower film quality consisting of the silicon oxide film was etched using a specific etching gas. Subsequently, the resist pattern remaining on the wafer was removed using a stripper to form a desired silicon oxide film pattern.

Example 13

Resist composition

Using the polymer synthesized in Example 6 (1.0 g), a resist composition was prepared in the same manner as in Example 12, and the obtained resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked for 90 seconds at a temperature of 110 ° C, exposed using a KrF excimer laser having a numerical aperture (NA) of 0.45, and then PEB for 90 seconds at a temperature of 110 ° C. Was carried out.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

When the exposure dose amount was set to about 23 mJ / cm ² , it was confirmed that a 0.4 μm line and space pattern was obtained.

Example 14

Resist composition

A resist composition was prepared in the same manner as in Example 12 using the polymer synthesized in Example 8 (1.0 g), triphenylsulfonium triflate (20 mg) as PAG, and triethanolamine (2 mg) as an organic base. The resulting resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked for 90 seconds at a temperature of 110 ° C, exposed using a KrF excimer laser having a numerical aperture (NA) of 0.45, and then PEB for 90 seconds at a temperature of 120 ° C. Was carried out.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

As a result, when the exposure dose amount was set to about 21 mJ / cm ² , it was confirmed that a 0.4 μm line-and-space pattern was obtained.

Example 15

Resist composition

Using the polymer synthesized in Example 9-1 (1.0 g), a resist composition was prepared in the same manner as in Example 12, and the obtained resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked at a temperature of 120 ° C. for 90 seconds, and exposed using an ArF excimer laser having a numerical aperture (NA) of 0.6, followed by 90 seconds at a temperature of 120 ° C. PEB was performed.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

Example 16

Resist composition

Using the polymer synthesized in Example 9-3 (1.0 g), a resist composition was prepared in the same manner as in Example 12, and the obtained resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked at a temperature of 120 ° C. for 90 seconds, and exposed using an ArF excimer laser having a numerical aperture (NA) of 0.6, followed by 90 seconds at a temperature of 110 ° C. PEB was performed.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

It was confirmed that a 0.3 μm line-and-space pattern was obtained when the exposure dose amount was set to about 14 mJ / cm ² .

Example 17

Resist composition

A resist composition was prepared in the same manner as in Example 12, using the polymer synthesized in Example 10-1 (1.0 g), triphenylsulfonium triflate (20 mg) as PAG, and triethanolamine (2 mg) as an organic base. The prepared and obtained resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked at a temperature of 120 ° C. for 90 seconds, and exposed using an ArF excimer laser having a numerical aperture (NA) of 0.6, followed by 90 seconds at a temperature of 110 ° C. PEB was performed.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

As a result, it was confirmed that a 0.3 μm line-and-space pattern was obtained when the exposure dose was set to about 16 mJ / cm ² .

Example 18

Resist composition

Using the polymer synthesized in Example 10-3 (1.0 g), a resist composition was prepared in the same manner as in Example 12, and the obtained resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked at a temperature of 120 ° C. for 90 seconds, and exposed using an ArF excimer laser having a numerical aperture (NA) of 0.6, followed by 90 seconds at a temperature of 120 ° C. PEB was performed.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

Example 19

Resist composition

The polymer synthesized in Example 11 (1.0 g), triphenylsulfonium triflate (10 mg) and methoxydiphenyl iodonium triflate (10 mg), which are PAG, and triisobutylamine (2 mg), which are organic bases, were used. The resist composition was prepared in the same manner as in Example 12, and the obtained resist composition was coated on a wafer. Thereafter, the wafer coated with the resist composition was prebaked at a temperature of 120 ° C. for 90 seconds, and exposed using an ArF excimer laser having a numerical aperture (NA) of 0.6, followed by 90 seconds at a temperature of 110 ° C. PEB was performed.

Thereafter, it was developed for about 60 seconds using a 2.38 wt% TMAH solution to form a resist pattern.

As a result, it was confirmed that a 0.3 μm line-and-space pattern is obtained when the exposure dose is about 13 mJ / cm ² .

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Since the photobone polymer according to the present invention has an alicyclic compound while the backbone has a cyclic structure, resistance to dry etching can be sufficiently secured.

In addition, the polymer according to the present invention may also be present in the form of a homopolymer or a copolymer. Therefore, by incorporating various comonomers to form a copolymer in order to enhance the resist properties, adhesion to the film can be improved, and a resist pattern can be prepared using a general developer, for example, a 2.38 wt% TMAH solution. It is possible to form.

Therefore, the resist composition made of the polymer according to the present invention can ensure sufficient resistance to dry etching, can exhibit very good lithography performance in any type of lithography process, and is very useful for manufacturing next-generation semiconductor devices in the future. It can be usefully used.

The present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention. Do.

Claims (3)

The photosensitive polymer which has a following formula and whose weight average molecular weights are 3,000-100,000.

Wherein R ₁ , R ₂ are each a hydrogen, methyl, ethyl or methoxy group, and R ₃ is a C ₁ to C ₂₀ aliphatic or alicyclic saturated compound. The photosensitive polymer according to claim 1, wherein R ₃ is adamantyl group, adamantanemethyl group, norbornyl group, norbornylmethyl group, isobornyl group, menthyl group, isomentyl group, methyl group or ethyl group. The photosensitive polymer of claim 1, Comonomers composed of alcohol, carboxylic acid, tert-butyl, or any one selected from the group consisting of norbornene and (meth) acrylate derivatives having an isobornyl group and contained in an amount of 1 to 30 mol% ( comonomer).