KR20060002454A - Photoresist Polymer and Photoresist Composition Comprising the Same - Google Patents

Abstract

FIELD OF THE INVENTION The present invention relates to photoresist polymers and photoresist compositions, and specifically relates to excellent transmittance, etch resistance, heat resistance, adhesion, and the like in light sources in the deep amplified deep ultraviolet (DUV) region, such as ArF and VUV light sources. The present invention relates to a photoresist polymer and a photoresist composition having a low light absorbance and having a high affinity for a developer and having a pattern having excellent line edge roughness (LER).

Description

Photoresist polymer and photoresist composition containing same {Photoresist Polymer and Photoresist Composition Containing it}

1 is a photoresist pattern photo formed by Example 7.

2 is a photoresist pattern photo formed by Example 8.

3 is a photoresist pattern photo formed by Example 9.

4 is a photoresist pattern photo formed by Example 10.

5 is a photoresist pattern photo formed by Example 11. FIG.

6 is a photoresist pattern photo formed by Example 12.

FIELD OF THE INVENTION The present invention relates to photoresist polymers and photoresist compositions, and specifically relates to excellent transmittance, etch resistance, heat resistance, adhesion, and the like in light sources in the deep amplified deep ultraviolet (DUV) region, such as ArF and VUV light sources. The present invention relates to a photoresist polymer and a photoresist composition having a low light absorbance and having a high affinity for a developer and having a pattern having excellent line edge roughness (LER).                         

In general, in order to be used as a photoresist material for a light source in the DUV region, the light absorption of the light source should be low, the etching resistance and the adhesion to the substrate should be excellent, and 2.38 wt% and 2.6 wt% of tetramethyl ammonium Many requirements must be met, such as development with an aqueous solution of hydroxide (TMAH). The main direction of research of photoresist materials to date is to develop materials with high transparency in KrF and ArF light sources, and at the same level of etch resistance as novolak resins.

However, since the photoresist formed on the etched layer becomes thinner as the pattern of the semiconductor device becomes more and more fine, most photoresists have excellent LER because the difference in the dissolution rate of the exposed portion and the non-exposed portion of the base resin is reduced. Not only is it difficult to form a pattern, but also a strong absorbance is observed in a VUV light source, which is not suitable as a photoresist for a VUV light source.

The LER is more severely generated in ArF photoresist than conventional KrF or I-line photoresist, since the conventional KrF or I-line photoresist includes acidic alcohol groups therein, Since most of the chemically amplified photoresist for ArF does not contain an acidic alcohol compound therein, the dissolution rate in the basic developer is more severely generated.

In order to solve the above problems, polyethylene and polyacrylate-based resins containing fluorine were used as the photoresist polymer, but polyethylene and polyacrylate-based resins containing fluorine had weak etching resistance, There is a disadvantage that the adhesion to the silicon substrate is greatly reduced.                         

In addition, the polyethylene and polyacrylate-based resin is difficult to mass-produce and high price, which is not suitable for commercial use, and gas is generated when the protecting group of the photoresist polymer is broken during the post-exposure baking process. Lens damage occurs. This phenomenon is indispensable in the pattern forming process using a chemically amplified photoresist, and reduces the device yield by inhibiting the stability of the semiconductor device during the subsequent process.

Accordingly, the present inventors have completed the present invention by developing a new concept of chemically amplified polymer polymer that overcomes the conventional problems while studying the above problems.

An object of the present invention is to provide a photoresist polymer having a low light absorption of a light source in a DUV region and a high dissolution rate for a developer, a photoresist composition comprising the polymer, and a pattern forming method using the same.

In order to achieve the above object,

The present invention provides a photoresist polymer comprising a polymer selected from the group consisting of polymers of the general formula (1) and the following general formula (2).                     

[Formula 1]

[Formula 2]

In Chemical Formulas 1 to 2,

R ₁ is straight or branched alkyl of C _{1 to} C ₅ ,

R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are Each H, C ₁ ~C ₂₀ alkyl, halogen, alkyl or ether group of C ₁ ~C ₂₀ alkyl containing an ether group (-O-) of the C ₁ ~C ₂₀ which has a halogen substituent (-O- ) And C ₁ -C ₂₀ alkyl having a halogen substituent,

R ₇ is H or straight or branched C ₁ -C ₁₀ alkyl,

a is an integer from 0 to 5, o is an integer from 1 to 5,

The relative ratio of m: n is 20-99 mol%: 80-1 mol%,

The relative ratio of p: q is 20-99 mol%: 80-1 mol%.

The polymer of the present invention has a molecular weight of 2,000 to 100,000.

The photoresist polymer of the present invention made of a compound containing an ethylene oxy group as described above has a high etching resistance and a low diffusion of acid during baking after exposure since the protecting group is released at a low temperature after exposure. A pattern having LER can be formed. In addition, since the photoresist polymer of the present invention includes a sultone-based compound, the photoresist polymer has a high adhesion to a silicon substrate, a low absorbance for a light source in a DUV region such as ArF and VUV light sources, and a post-exposure baking ( Out-gassing does not occur during the baking process to prevent damage to the lens.

It is preferable that the polymer of Formula 1 is a polymer represented by the following Formula 1a to Formula 1c.                     

[Formula 1a]

[Formula 1b]

[Formula 1c]

In Chemical Formulas 1a to 1c,

The relative ratio of m: n is 20-99 mol%: 80-1 mol%.

In addition, the polymer of Formula 2 is preferably a polymer represented by the following formula (2a) to (2c).

[Formula 2a]

[Formula 2b]

[Formula 2c]

In Chemical Formulas 2a to 2c,

The relative ratio of p: q is 20-99 mol%: 80-1 mol%.

In addition, in the present invention, in order to obtain the polymer of Formula 1 or Formula 2,

(a) dissolving at least one compound selected from the group consisting of a compound of Formula 3 and a compound of Formulas 4 and 5 in a polymerization solvent; And

(b) providing a polymer production method of a photoresist comprising the step of polymerizing the reaction solution in the presence of a polymerization initiator.

[Formula 3]

[Formula 4]

[Formula 5]

Wherein R ₁ is straight or branched C ₁ -C ₅ alkyl,

R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are Each H, C ₁ a C ₁ ~C ₂₀ having a ~C ₂₀ alkyl, halogen, halogen substituted alkyl, an ether group (-O-) C ₁ ~C ₂₀ alkyl or ether group comprising (-O-) C _{1 ~} C ₂₀ Alkyl containing a halogen substituent,

R ₇ is H or straight or branched C ₁ -C ₁₀ alkyl,

a is an integer of 0-5, o is an integer of 1-5.

Since the polymer of the present invention is produced by radical polymerization, it is also possible to use bulk polymerization or a metal catalyst disclosed in WO 96/37526 (1996.11.28) in addition to the above solution polymerization.

The polymerization solvent is used alone or in combination with a solvent selected from the group consisting of cyclohexanone, cyclopentanone, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, dioxane, methylethylketone, benzene, toluene and xylene do.

The polymerization initiator is 2,2'-azobisisobutyronitrile (AIBN), benzoyl peroxide, acetyl peroxide, lauryl peroxide, t-butyl peracetate, di-t-butyl peroxide and t-butyl hydride One selected from the group consisting of loperoxides is used.

The polymer of the present invention prepared by the above method is further crystallized using a single or mixed solvent such as diethyl ether, petroleum ether, alkane, alcohol, acetone and water.

The polymer of the present invention may further include a vinylene-based or acrylic-based polymer, if necessary, in addition to the polymer of Chemical Formula 1 or 2 above.                     

The present invention also provides a photoresist composition comprising the photoresist polymer of the present invention, a photoacid generator and an organic solvent.

The photoacid generator may be used as long as the compound can generate an acid by light, US 5,212,043 (May 18, 1993), WO 97/33198 (September 12, 1997), WO 96/37526 (1996. 11.28), EP 0794458 (September 10, 1997), EP 0789278 (August 13, 1997), US 5,750,680 (May 12, 1998), US 6,051,678 (April 18, 2000), GB 2,345,286 A (2000) 7. 5), US 6,132,926 (October 17, 2000), US 6,143,463 (11/7/2000), US 6,150,069 (11/21/2000), US 6.180.316 B1 (January 30, 2001), US 6,225,020 B1 (May 1, 2001), US 6,235,448 B1 (May 22, 2001) and US 6,235,447 B1 (May 22, 2001) and the like, and mainly include sulfide-based or onium salt-based compounds, In particular, phthalimidotrifluoromethane sulfonate, dinitrobenzyltosylate, n-decyl disulfone, and naphthylimidotrifluoro have relatively low absorbance at 157 nm and 193 nm. Romethanesulfonate (naphthylimido triflu oromethane sulfonate) is preferably used, together with diphenyl iodo hexafluorophosphate, diphenyl iodo hexafluoro arsenate, diphenyl iodo hexafluoro antimonate, diphenylparame Methoxyphenylsulfonium triflate, diphenylparatoluenylsulfonium triflate, diphenylparaisobutylphenylsulfonium triflate, triphenylsulfonium hexafluoro arsenate, triphenylsulfonium hexafluoro antimonate, It is also possible to use a photoacid generator selected from the group consisting of triphenylsulfonium triflate and dibutylnaphthylsulfonium triflate. The photoacid generator is preferably included in a ratio of 0.05 to 10 parts by weight with respect to 100 parts by weight of the photoresist polymer, when included in an amount of 0.05 parts by weight or less, the sensitivity of the photoresist to light and 10 parts by weight When included, the photoacid generator absorbs a lot of ultraviolet rays, and a large amount of acid is generated to obtain a pattern having a poor cross section.

The organic solvent includes those disclosed in the document, as long as any organic solvent commonly used in the photoresist composition can be used, preferably diethylene glycol diethyl ether, methyl 3-methoxy Methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, cyclohexanon, 2-heptanone or ethyl lac Tate and the like may be included alone or in combination. The organic solvent may be selected in an appropriate amount to obtain a photoresist film having a desired thickness, but is generally included in the ratio of 500 to 2000 parts by weight based on 100 parts by weight of the photoresist polymer. For example, the thickness of the photoresist obtained when 1100 parts by weight of the organic solvent is included with respect to the photoresist polymer is about 0.25 mu m.

The present invention also provides a photoresist pattern forming method comprising the following steps:

(a) applying the above-described photoresist composition of the present invention on the etched layer to form a photoresist film;                     

(b) exposing the photoresist film;

(c) baking the exposed photoresist film; And

(d) developing the resultant to obtain a desired pattern.

In the above process, it may further comprise the step of performing a baking process before exposure, this baking process is carried out at 70 to 200 ℃.

The exposure process may use any light source such as KrF, ArF, VUV, EUV, E-beam, X-ray or ion beam as a light source, preferably using ArF, VUV or EUV light source, 1 to 100mJ / cm ^It is carried out with an exposure energy of ^two .

On the other hand, the development of step (d) is preferably carried out using an alkaline developer, for example 0.01 to 5wt% TMAH aqueous solution.

The present invention also provides a semiconductor device manufactured using the pattern formation method described above.

Hereinafter, the present invention will be described in detail by examples. However, the examples are only to illustrate the invention and the present invention is not limited by the following examples.

I. Preparation of Photoresist Monomer

Preparation Example 1 Preparation of Compound of Formula 3a

2,3,4,4-tetramethyl-1,3-propane sultone (0.1M) was dissolved in anhydrous tetrahydrofuran under nitrogen atmosphere. NaH (0.1M) was added. Then, after stirring for 10 minutes, allyl bromide (0.11M) was added, and the reaction was further performed for 3 hours while adding the temperature to room temperature. After completion of the reaction, the reaction mixture was filtered to remove NaBr, and then crystallized in a dimethyl ether / pentane mixed solution to obtain a pure compound of formula 3a (87%).

[Formula 3a]

Preparation Example 2 Preparation of Compound of Formula 3b

Except for using 2,3,3,4,4-pentamethyl-1,3-propanesultone instead of 2,3,4,4-tetramethyl-1,3-propane sultone of Preparation Example 1, Synthesis was carried out in the same manner as in Preparation Example 1 to obtain a compound of formula 3b (86%).

[Formula 3b]

II. Preparation of Photoresist Polymer

Example 1 Synthesis of Polymer of Formula 1a

The compound of formula 3a (0.1M), the compound of formula 4a (0.01M) and AIBN (0.20 g) of Preparation Example 1 were dissolved in tetrahydrofuran (10 ml), and then reacted at 65 ° C. for 12 hours. After the reaction, the mixture was purified with hexane and dried in vacuo to obtain a photoresist polymer of formula 1a of the present invention (58%).

[Formula 4a]

Example 2. Synthesis of Polymer of Formula 1b

The compound of formula 3a (0.1M), the compound of formula 4b (0.01M) and AIBN (0.20 g) of Preparation Example 1 were dissolved in tetrahydrofuran (10 ml), and then reacted at 65 ° C. for 12 hours. After the reaction, the mixture was purified with hexane and dried in vacuo to obtain a photoresist polymer of formula 1b of the present invention (50%).

[Formula 4b]

Example 3 Synthesis of Polymer of Formula 1c

Compound (B) of Formula 3b (0.1M), Compound 4b (0.01M), and AIBN (0.20 g) of Preparation Example 2 were dissolved in tetrahydrofuran (10 ml), and then reacted at 65 ° C. for 12 hours. After the reaction, the mixture was purified with hexane and dried in vacuo to obtain a photoresist polymer of formula 1c of the present invention (54%).

Example 4. Synthesis of Polymer of Formula 2a

The compound of Formula 3a (0.1M), Formula 5a (0.01M) and AIBN (0.20g) of Preparation Example 1 were dissolved in tetrahydrofuran (10ml), and then reacted at 65 ° C for 12 hours. After the reaction, the mixture was purified with hexane and then dried in vacuo to give a photoresist polymer of formula 2a of the present invention (58%).

[Formula 5a]

Example 5 Synthesis of Polymer of Formula 2b

The compound of Formula 3a of Preparation Example 1 (0.1M), the compound of Formula 5b (0.01M), and AIBN (0.20g) were dissolved in tetrahydrofuran (10ml), and then reacted at 65 ° C for 12 hours. After the reaction, the mixture was purified with hexane and dried in vacuo to obtain a photoresist polymer of formula 2b of the present invention (50%).                     

[Formula 5b]

Example 6 Synthesis of Polymer of Formula 2c

Compound (B) of Formula 3b (0.1M), Formula 5b (0.01M) and AIBN (0.20 g) of Preparation Example 2 were dissolved in tetrahydrofuran (10 ml), and then reacted at 65 ° C. for 12 hours. After the reaction, the mixture was purified with hexane and dried in vacuo to obtain a photoresist polymer of formula 2c of the present invention (54%).

II. Preparation of Photoresist Composition and Forming Photoresist Pattern

Example 7.

The polymer (2 g) prepared in Example 1, phthalimidotrifluoromethanesulfonate (0.024 g) and triphenylsulfonium triflate (0.06 g), which are photoacid generators, were produced by propylene glycol methyl ethyl acetate (PGMEA) (22 g). It was dissolved in and filtered through a 0.20 μm filter to obtain a photoresist composition.

The photoresist composition thus obtained was spin-coated on the etching target layer of the silicon wafer to prepare a photoresist thin film, followed by soft baking for 90 seconds in an oven or hot plate at 130 ° C., and then exposed to light using an ArF laser exposure apparatus, followed by 90 ° at 130 ° C. Bake again for a second. The baked wafer was immersed in a 2.38 wt% TMAH aqueous solution for 40 seconds to develop an L / S pattern of 0.07 μm (see FIG. 1).

Example 8.

A photoresist composition was prepared in the same manner as in Example 7, except that the polymer (2 g) prepared in Example 2 was used instead of the polymer prepared in Example 1, and L was 0.07 μm using the composition. A / S pattern was formed (see FIG. 2).

Example 9.

A photoresist composition was prepared in the same manner as in Example 7, except that the polymer (2 g) prepared in Example 3 was used instead of the polymer prepared in Example 1, and L was 0.07 μm using the composition. A / S pattern was formed (see FIG. 3).

Example 10.

A photoresist composition was prepared in the same manner as in Example 7, except that the polymer (2 g) prepared in Example 4 was used instead of the polymer prepared in Example 1, and L was 0.07 μm using the composition. A / S pattern was formed (see FIG. 4).

Example 11.

A photoresist composition was prepared in the same manner as in Example 7, except that the polymer (2 g) prepared in Example 5 was used instead of the polymer prepared in Example 1, and L was 0.07 μm using the composition. A / S pattern was formed (see FIG. 5).

Example 12.

A photoresist composition was prepared in the same manner as in Example 7, except that the polymer (2 g) prepared in Example 6 was used instead of the polymer prepared in Example 1, and L was 0.07 μm using the composition. A / S pattern was formed (see FIG. 6).

As described above, since the photoresist polymer of the present invention contains a compound of ethylene oxy group, the protecting group is released at a low temperature after exposure, so that the diffusion of acid during the post-exposure baking decreases, thereby improving LER. In addition to obtaining a printed pattern, since it contains a sultone group, it has high adhesion to a silicon substrate, has a low absorbance for a light source in a DUV region such as an ArF and VUV light source, and desorbs in a post-exposure baking process. Out-gassing does not occur to prevent damage to the lens. In addition, it is excellent in durability, etching resistance, reproducibility, and resolution, and can form ultra-fine patterns of 4G and 16G DRAMs as well as DRAMs of 1G or less.

Claims (18)

A photoresist polymer comprising a polymer selected from the group consisting of polymers of Formulas 1 and 2 [Formula 1]

[Formula 2]

(Wherein R ₁ is straight or branched alkyl of C _{1 to} C ₅ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are Each H, C ₁ a C ₁ ~C ₂₀ having a ~C ₂₀ alkyl, halogen, halogen substituted alkyl, an ether group (-O-) C ₁ ~C ₂₀ alkyl or ether group comprising (-O-) C _{1 ~} C ₂₀ Alkyl containing a halogen substituent, R ₇ is H or straight or branched C ₁ -C ₁₀ alkyl, a is an integer from 0 to 5, o is an integer from 1 to 5, The relative ratio of m: n is 20-99 mol%: 80-1 mol%, the relative ratio of p: q is 20-99 mol%: 80-1 mol%). The method of claim 1, The polymer has a molecular weight of 2,000 to 100,000 characterized in that the photoresist polymer. The method of claim 1, The polymer is a photoresist polymer, characterized in that it comprises a polymer of formula 1a to formula 1c: [Formula 1a]

[Formula 1b]

[Formula 1c]

(In Chemical Formulas 1a to 1c the relative ratio of m: n is 20-99 mol%: 80-1 mol%). The method of claim 1, The polymer is a photoresist polymer, characterized in that it comprises a polymer of formula 2a to formula 2c: [Formula 2a]

[Formula 2b]

[Formula 2c]

(In Chemical Formulas 2a to 2c, the relative ratio of p: q is 20-99 mol%: 80-1 mol%). In order to prepare a polymer of Formula 1 or 2, (a) dissolving at least one compound selected from the group consisting of a compound of Formula 3 and a compound of Formulas 4 and 5 in a polymerization solvent; And (b) polymerizing the reaction solution in the presence of a polymerization initiator; [Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

(Wherein R ₁ is straight or branched alkyl of C _{1 to} C ₅ , _{R 2, R 3, R 4} , R 5 and R ₆ is alkyl, halogen, a C ₁ ~C ₂₀ alkyl substituent having a halogen, an ether group (-O-) alkyl, ethers of C ₁ ~C ₂₀ containing C ₁ -C ₂₀ alkyl containing a group (-O-) and having a halogen substituent R ₇ is H or straight or branched C ₁ -C ₁₀ alkyl, a is an integer of 0 to 5, o is an integer of 1 to 5, The relative ratio of m: n is 20-99 mol%: 80-1 mol%, the relative ratio of p: q is 20-99 mol%: 80-1 mol%). The method of claim 5, The polymerization solvent is at least one selected from the group consisting of cyclohexanone, cyclopentanone, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone, benzene, toluene and xylene Method of Making Polymers. The method of claim 5, The polymerization initiator is 2,2'-azobisisobutyronitrile (AIBN), benzoyl peroxide, acetyl peroxide, lauryl peroxide, t-butyl peracetate, di-t-butyl peroxide and t-butyl hydride A method for producing a photoresist polymer, characterized in that selected from the group consisting of loperoxide. The method of claim 5, The polymer is a method for producing a photoresist polymer, characterized in that further comprising the step of crystallization using at least one solvent selected from the group consisting of diethyl ether, petroleum ether, alkane, alcohol, acetone and water. The method of claim 1, The polymer is a photoresist polymer further comprises a vinylene or acrylic polymer. A photoresist composition comprising the photoresist polymer according to claim 1, a photoacid generator and an organic solvent. The method of claim 10, The photoacid generators include phthalimidotrifluoromethane sulfonate, dinitrobenzyltosylate, n-decyl disulfone, and naphthylimidotrifluoromethanesulfonate. trifluoromethane sulfonate) photoresist composition, characterized in that selected from the group consisting of. The method of claim 11, The photoacid generator is diphenyl iodo hexafluorophosphate, diphenyl iodo hexafluoro arsenate, diphenyl iodo hexafluoro antimonate, diphenyl paramethoxyphenylsulfonium triflate, diphenyl paratolue Nylsulfonium triflate, diphenylparaisobutylphenylsulfonium triflate, triphenylsulfonium hexafluoro arsenate, triphenylsulfonium hexafluoro antimonate, triphenylsulfonium triflate and dibutylnaphthylsulfonium A photoresist composition further comprising a compound selected from the group consisting of triflate. The method of claim 10, The photoresist is a photoresist composition, characterized in that contained in a ratio of 0.05 to 10 parts by weight based on 100 parts by weight of the photoresist polymer. The method of claim 10, The organic solvent is diethylene glycol diethyl ether, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl A photoresist composition, characterized in that at least one selected from the group consisting of ether acetate, cyclohexanon, 2-heptanone and ethyl lactate. The method of claim 10, The organic solvent is a photoresist composition, characterized in that contained in a ratio of 500 to 2000 parts by weight based on 100 parts by weight of the photoresist polymer. (a) applying the photoresist composition of claim 10 over the etched layer to form a photoresist film; (b) exposing the photoresist film; (c) baking the exposed photoresist film; And (d) developing the resultant to obtain a desired pattern. The method of claim 16, The exposure process is a photoresist pattern forming method characterized in that the ArF, VUV (Vacuum Ultra Violet) or EUV (Extreme Ultra Violet) light source. A semiconductor device manufactured by the method of claim 16.

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