KR100680427B1 - Photoresist Polymer and Photoresist Composition Containing it - Google Patents

Abstract

The present invention relates to a photoresist polymer and a photoresist composition, wherein the photoresist polymer comprising the moiety of Formula 1 and the photoresist composition of the present invention containing the polymer are not only 248 nm and 157 nm but also 13 nm wavelength. Since it has transmittance, etching resistance, heat resistance, adhesiveness and low light absorption, and high affinity for a developer, line edge roughness (LER) can be improved.

[Formula 1]

Where

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are as defined in the specification.

Description

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

1 is a photoresist pattern photo formed by Example 5.

2 is a photoresist pattern photo formed by Example 6.

3 is a photoresist pattern photo formed by Example 7.

4 is a photoresist pattern photo formed by Example 8.

The present invention relates to a photoresist polymer and a photoresist composition, wherein the photoresist polymer comprising a moiety of the general formula (1) and the photoresist composition of the present invention containing the polymer are not only 248 nm and 157 nm but also 13 Even at the wavelength of nm, the film has transmittance, etching resistance, heat resistance, adhesion, and low light absorption, and has high affinity for a developer, thereby improving line edge roughness (LER).

In general, in order to be used as photoresist for ArF and vacuum ultraviolet light (VUV), the light absorption at the wavelength of 193nm and 157nm should be low, the etching resistance and the adhesion to the substrate should be excellent, and the 2.38wt% and 2.6wt% Many requirements must be met, such as developing with aqueous tetramethyl ammonium hydroxide (TMAH).

The main research direction to date has been to search for resins with high transparency at 248 nm and 193 nm with the same etching resistance as novolak resin.

However, in most of these resists, as the circuit of the device becomes smaller and smaller, the resist thickness is also lowered, thereby improving the LER of the pattern.

The LER is more severely generated in the ArF resist pattern than the conventional KrF or I-line resist pattern. The reason for this is that in the case of the conventional KrF or I-line resist, the acidic alcohol group is included in the resist. Since the ArF resist does not contain an acidic alcohol compound therein, the ArF resist has a low affinity for the basic developer and is more severely generated.

This phenomenon is indispensable in the case of the pattern formation process using a chemically amplified resist, and lowers the stability of the process by inhibiting the stability and yield characteristics of the semiconductor device during the subsequent process.

Therefore, the inventors of the present invention provide a photoresist polymer and a photoresist composition containing the polymer, which have a high transmittance, etching resistance, heat resistance, adhesion, and low light absorption, and have a high affinity for a developer in order to obtain an improved pattern of LER. It aims to provide.

In order to achieve the above object, the present invention provides a polymer comprising an acidic alcohol group and a boron compound, a composition comprising the polymer, and a photoresist pattern forming method using the same.

In the present invention below

The main chain comprises addition polymerization of a cycloolefin compound,

It provides a photoresist polymer having a side chain bonded to the moiety of the formula (1) in the main chain

[Formula 1]

Where

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each an H, F, CF ₃ or C ₁ -C ₅ alkyl group.

The moiety of Chemical Formula 1 is preferably the following Chemical Formulas 1a to 1d.

[Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

In addition, the polymer of the present invention contains 1 to 30 mol%, preferably 5 to 25 mol% of the moiety of the formula (1). At this time, the moiety of the formula (1) is preferably cross-linking defects between the main chain.

It is preferable that the main chain of the said polymer contains the addition polymer of following formula (2).

[Formula 2]

Where

X ₁ and X ₂ are each CH ₂ , O or S,

m is an integer of 0 to 2, n is 0 or 1;

Formula 2 is preferably represented by the following formula (2a).

[Formula 2a]

In addition, the polymer of the present invention preferably comprises a polymerization repeating unit of the following formula (3) or formula (4) comprising the formula (1) and (2).

[Formula 3]

[Formula 4]

In Chemical Formulas 3 and 4

X ₁ and X ₂ are each CH ₂ , O or S,

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each an H, F, CF ₃ or C ₁ -C ₅ alkyl group,

m is an integer from 0 to 2, n is 0 or 1,

o: p is 60 to 90 mol%: 10 to 40 mol%, q: r is 60 to 90 mol%: 10 to 40 mol%.

Since the polymer of the present invention contains an acidic alcohol group, not only has a high affinity for the basic developer, but also contains a fluorine atom in the polymer, and is a hybrid made of an existing acrylate-based and cycloolefin-based. It is possible to reduce the high light absorbency which is a problem of form photoresist.

Preferred examples of the polymerization repeating unit of Chemical Formula 3 are as shown in the following Chemical Formulas 3a to 3d.

[Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

In Chemical Formulas 3a to 3d

The relative ratio of o: p is 60-90 mol%: 10-40 mol%.

In addition, a preferred example of the polymerization repeating unit of the formula (4) is the same as the formula (4a) to 4d.

[Formula 4a]

[Formula 4b]

[Formula 4c]

[Formula 4d]

In Chemical Formulas 4a to 4d

The relative ratio of q: r is 60-90 mol%: 10-40 mol%.

In the present invention,

(a) mixing the addition polymer of Formula 2 and the compound of Formula 1e with an organic solvent; And

(b) providing a method of preparing a photoresist polymer comprising the step of obtaining the polymer of the present invention while refluxing the reactant.

[Formula 1e]

그룹이 탈리되어 상기 중합체가 유기용매에 용해된다.In the above reaction, the homopolymer made of the addition polymer of Chemical Formula 2 is a material in which the developer is soluble, but when a crosslinking reaction occurs by condensation with the moiety of Chemical Formula 1, a homopolymer is produced. This polymer is broken by the acid generated during the exposure process, the -OBO- portion,

The group is detached to dissolve the polymer in the organic solvent.

The polymer of the present invention produced by the condensation reaction is a polymerization repeating unit consisting of the formula (3) and formula (4) is mixed, such a polymer mixture may be included in the photoresist composition, by separating the polymer of the formula (3) and (4) It may also be included in the composition.

In addition, the present invention provides a photoresist composition comprising a photoresist polymer prepared by the condensation reaction, a photoacid generator and an organic solvent.

In this case, the composition may further include a vinylene-based or acrylic polymer.

The photoacid generator may be used as long as it is a compound capable of generating an acid by light, US 5,212,043 (May 18, 1993), WO 97/33198 (Sept. 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 sulfur-based or onium salt-based compounds are used. In particular, low absorbance phthalimidotrifluoromethane sulfonate, dinitrobenzyltosylate, n-decyl disulfone and naphthylimidotrifluoromethane at 157 nm and 193 nm Preference is given to using those selected from the group consisting of naphthylimido trifluoromethane sulfonate, together with diphenylurodoxyl hexafluorophosphate, diphenylurodoxyl hexafluoro arsenate, diphenylurodoxyl hexafluoro antimonate, Diphenylparamethoxyphenylsulfonium triflate, diphenylparatoluenylsulfonium triflate, diphenylparaisobutylphenylsulfonium triflate, triphenylsulfonium hexafluoro arsenate, triphenylsulfonium hexafluoro Antimonate, triphenylsulfonium triflate and dibutylnaphthylsulfonium tri It is also possible to use a photoacid generator selected from the group consisting of plates, it is preferable to use a ratio of 0.05 to 10wt% based on the photoresist polymer. When the photoacid generator is used in an amount of less than 0.05wt%, the sensitivity of the photoresist to light is weak. When the photoacid generator is used above 10wt%, the photoacid generator absorbs a lot of ultraviolet rays and generates a large amount of acid, thereby obtaining a pattern having a bad cross section.

In addition, the organic solvent can be used in any one, US 5,212,043 (May 18, 1993), WO 97/33198 (Sept. 12, 1997), WO 96/37526 (Nov. 28, 1996), EP 0794458 (1997) 9.10), EP 0789278 (August 13, 1997), US 5,750,680 (May 12, 1998), US 6,051,678 (April 18, 2000), GB 2,345,286 A (July 5, 2000), US 6,132,926 ( Oct. 17, 2000, US 6,143,463 (Nov. 7, 2000), US 6,150,069 (Nov. 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, preferably diethylene glycol diethyl ether, methyl 3-methoxyprop Methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, cyclohexanon or 2-heptanone alone Or it can be used in combination, 500 to 2000 for the photoresist polymer It is used in a wt% ratio, which is to obtain a photoresist film of a desired thickness, for example, the photoresist thickness when the organic solvent is 1000 wt% is used for the photoresist polymer is about 0.25 μm.

The present invention also provides a method of forming a photoresist pattern consisting of 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 is performed using an exposure energy of 1 to 100 mJ / cm ² using Ar, as well as KrF, Extreme Ultra Violet (EUV), Vacuum Ultra Violet (VUV), E-beam, X-ray or ion beam. desirable.

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 Polymer

Example 1 Synthesis of Polymers of Formulas 3a and 4a

After dissolving the polymer of the compound of Formula 2a (0.1M) and the compound of Formula 1a (0.01M) in toluene (100ml), and refluxed for 12 hours, a dean-stark device To dehydrate. After the reaction, the mixture was cooled to room temperature to precipitate and filter the polymer, thereby obtaining a polymer in which Chemical Formulas 3a and 4a were mixed (total yield: 97%).

Example 2. Synthesis of Polymers of Formulas 3b and 4b

The polymer (0.1 M) consisting of the compound of Formula 2a and the compound of Formula 1b (0.01 M) were dissolved in toluene (100 ml), and then dehydrated using a Dean-Stark apparatus while refluxing for 12 hours. After the reaction, the mixture was cooled to room temperature to precipitate and filter the polymer, thereby obtaining a polymer in which Chemical Formulas 3b and 4b were mixed (total yield: 96%).

Example 3. Synthesis of Polymers of Formulas 3c and 4c

The polymer (0.1 M) consisting of the compound of Formula 2a and the compound of Formula 1c (0.01 M) were dissolved in toluene (100 ml) and dehydrated using a Dean-Stark apparatus while refluxing for 12 hours. After the reaction, the mixture was cooled to room temperature to precipitate and filter the polymer, thereby obtaining a polymer in which Chemical Formulas 3c and 4c were mixed (total yield: 96%).

Example 4 Synthesis of Polymers of Formulas 3d and 4d

The polymer (0.1M) consisting of the compound of Formula 2a and the compound of Formula 1d (0.01M) were dissolved in toluene (100 ml) and dehydrated using a Dean-Stark apparatus while refluxing for 12 hours. After the reaction, the mixture was cooled to room temperature, and the polymer was precipitated and filtered to obtain a polymer in which Chemical Formulas 3d and 4d were mixed (total yield: 98%).

II. Preparation and Pattern Formation of Photoresist Composition

Example 5.

The polymer (2 g) prepared in Example 1, phthalimidotrifluoromethanesulfonate (0.024 g) and triphenylsulfonium triflate (0.06 g), which are photoacid generators, were propylene glycol methyl ethyl acetate (PGMEA) (30 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 0.08 μm (see FIG. 1).

Example 6.

A photoresist composition was prepared in the same manner as in Example 5, except that the polymer (2 g) prepared in Example 2 was used instead of the polymer prepared in Example 1, and L / S of 0.08 μm was used using the composition. An S pattern was formed (see FIG. 2).

Example 7.

A photoresist composition was prepared in the same manner as in Example 5, except that the polymer (2 g) prepared in Example 3 was used instead of the polymer prepared in Example 1, and the L / s of 0.08 μm was used. An S pattern was formed (see FIG. 3).

Example 8.

A photoresist composition was prepared in the same manner as in Example 5, except that the polymer (2 g) prepared in Example 4 was used instead of the polymer prepared in Example 1, and L / S of 0.08 μm was used using the composition. An S pattern was formed (see FIG. 4).

As described above, since the photoresist composition of the present invention contains an acidic alcohol group, the affinity for the basic developer is high, and the LER is not only improved, but also contains fluorine. In addition, it has a low absorbance in the 157 nm region, and 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 (23)

The main chain comprises an addition polymerization unit of a cycloolefin compound, The photoresist polymer, characterized in that the moiety of the formula (1) is side chain bonded to the main chain. [Formula 1]

Where R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each an H, F, CF ₃ or C ₁ -C ₅ alkyl group. The method of claim 1, The moiety of Formula 1 is a photoresist polymer, characterized in that selected from the group consisting of the formula 1a to 1d: [Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

. The method of claim 1, A photoresist polymer comprising the moiety of the formula (1) at 1 to 30 mol% based on the total mol% of the cycloolefin addition polymerization unit. The method of claim 1, The moiety of Formula 1 is cross-linked between the main chain photoresist polymer. The method of claim 1, The main chain is a photoresist polymer, characterized in that it comprises an addition polymer of the formula [Formula 2]

Where X ₁ and X ₂ are each CH ₂ , O or S, m is an integer of 0 to 2, n is 0 or 1; The method of claim 5, Formula 2 is a photoresist polymer, characterized in that represented by the formula (2a). [Formula 2a]

The method of claim 1, The polymer is a photoresist polymer, characterized in that it comprises a polymerization repeating unit of the formula (3) or (4). [Formula 3]

[Formula 4]

In Chemical Formulas 3 and 4 X ₁ and X ₂ are each CH ₂ , O or S, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each an H, F, CF ₃ or C ₁ -C ₅ alkyl group, m is an integer from 0 to 2, n is 0 or 1, o: p is 60 to 90 mol%: 10 to 40 mol%, q: r is 60 to 90 mol%: 10 to 40 mol%. The method of claim 7, wherein The polymerization repeating unit of Formula 3 is a photoresist polymer, characterized in that selected from the group consisting of the following formula 3a to 3d: [Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

In Chemical Formulas 3a to 3d The relative ratio of o: p is 60-90 mol%: 10-40 mol%. The method of claim 7, wherein The polymerization repeating unit of Formula 4 is a photoresist polymer, characterized in that selected from the group consisting of the following formula 4a to 4d: [Formula 4a]

[Formula 4b]

[Formula 4c]

[Formula 4d]

In Chemical Formulas 4a to 4d The relative ratio of q: r is 60-90 mol%: 10-40 mol%. (a) mixing an addition polymer of Formula 2 with a compound of Formula 1e to an organic solvent; And (b) obtaining a polymer of the present invention while refluxing and reacting the reactants. [Formula 1e]

[Formula 2]

Where X ₁ and X ₂ are each CH ₂ , O or S, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each an H, F, CF ₃ or C ₁ -C ₅ alkyl group, m is an integer of 0 to 2, n is 0 or 1; A photoresist composition comprising the photoresist polymer according to claim 1, a photoacid generator and an organic solvent. The method of claim 11, In addition to the cycloolefin polymer, the composition further comprises a vinylene-based or acrylate-based polymer. The method of claim 11, The photoacid generators are phthalimidotrifluoromethane sulfonate, dinitrobenzyltosylate, n-decyl disulfone, and naphthylimidotrifluoromethanesulfonate (naphthylimido). trifluoromethane sulfonate) photoresist composition, characterized in that selected from the group consisting of. The method of claim 13, In addition to the photoacid generator, diphenyl iodo hexafluorophosphate, diphenyl iodo hexafluoro arsenate, diphenyl iodo hexafluoro antimonate, diphenyl paramethoxyphenylsulfonium triflate, diphenyl paratoluene Nylsulfonium triflate, diphenylparaisobutylphenylsulfonium triflate, triphenylsulfonium hexafluoro arsenate, triphenylsulfonium hexafluoro antimonate, triphenylsulfonium triflate and dibutylnaphthylsulfonium Photoresist composition, characterized in that used together with the one selected from the group consisting of triflate. The method of claim 11, A photoresist composition, characterized in that the photoacid generator is used in a proportion of 0.05 to 10 wt% based on the photoresist polymer. The method of claim 11, The organic solvent is diethylene glycol diethyl ether, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propylene glycol methyl Photoresist composition, characterized in that selected from the group consisting of ether acetate, cyclohexanon (cyclohexanon) and 2-heptanone (n-heptanone). The method of claim 11, The organic solvent is a photoresist composition, characterized in that used in 500 to 2000wt% relative to the photoresist polymer. (a) applying and baking the photoresist composition of claim 11 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. delete The method of claim 18, The baking process is a photoresist pattern forming method, characterized in that performed at 70 to 200 ℃. The method of claim 18, The exposing process is performed using ArF, KrF and EUV (Extreme Ultra Violet), VUV (Vacuum Ultra Violet), E-beam, X-ray or ion beam. The method of claim 18, The exposure process is a photoresist pattern forming method, characterized in that performed with an exposure energy of 0.1 to 100mJ / cm ² . The method of claim 18, The development of the step (d) is a photoresist pattern forming method, characterized in that carried out using an alkaline developer.

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